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  • 51.
    Bröms, Jeanette
    et al.
    Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology). Department of Medical Countermeasures, Swedish Defence Research Agency.
    Forslund, Anna-Lena
    Department of Medical Countermeasures, Swedish Defence Research Agency.
    Forsberg, Åke
    Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology). Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Department of Medical Countermeasures, Swedish Defence Research Agency.
    Francis, Matthew
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology).
    PcrH of Pseudomonas aeruginosa is essential for secretion and assembly of the type III translocon2003In: Journal of Infectious Diseases, ISSN 0022-1899, E-ISSN 1537-6613, Vol. 188, no 12, p. 1909-1921Article in journal (Refereed)
    Abstract [en]

    Pseudomonas aeruginosa harbors a type III secretion system that translocates antihost effectors into an infected eukaryotic cell. PcrH is a key component of type III secretion in this essential virulence strategy. In the absence of PcrH, P. aeruginosa is translocation deficient because of a specific reduction in presecretory stability and subsequent secretion of PopB and PopD, 2 proteins essential for the translocation process. PcrH exerts this chaperone function by binding directly to PopB and PopD. Consistent with the genetic relatedness of PcrH with LcrH of pathogenic Yersinia species, these proteins are functionally interchangeable with respect to their ability to complement the translocation defect associated with either a lcrH or pcrH null mutant, respectively. Thus, the translocator class of chaperones performs a critical function in ensuring the assembly of a translocation competent type III secreton. Finally, unlike the regulatory roles of other translocator-class chaperones (e.g., LcrH, SicA of Salmonella enterica, and IpgC of Shigella species), in vitro regulation of P. aeruginosa type III secretion does not involve PcrH.

  • 52.
    Burman, Lars Å.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Streptococcus pneumoniae: epidemiological, clinical and serological studies1993Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    A retrospective study of invasive pneumococcal disease in patients from Greater Göteborg in 1964- 1980 identified 125 cases of meningitis, 305 of pneumonia, 61 of septicemia with unknown focus, and 17 with other manifestations, all verified by cultures from normally sterile body fluids. The incidence was several times higher in infants and in the elderly than in any other age-group. A wide variety of underlying conditions were present in 23% of the infants, 34% of the children, and 81% of the adults. In adults alcoholism was known in one third of the cases. The case fatality rate was 24% among patients with underlying conditions and 9% among previously healthy individuals. The case fatality rate was 50% in patients with hospital-acquired infection.

    Twohundred-fifteen pneumococcal strains, isolated from blood or CSF from 1971 to 1983 at the laboratories of clinical bacteriology of Göteborg, Malmö, and Umeå were serotyped by coagglutination (COA). Of all isolates, 89% belonged to serotypes represented in the 23-valent vaccine. In a separate study COA was compared with counterimmunoelectrophoresis (CIE). COA was found to have several advantages; rapidity, lower cost, and ability to disclose serotypes with neutral charge, which constituted 19% of all strains.

    In a prospective study the etiology was determined in 196 hospitalized patients with pneumonia, most of them community-acquired. Culture of specimens from blood, transtracheal aspirate (TTA), sputum, and nasopharynx, assays of antigen in sputum, urine, and TTA, and assays of pneumococcal antibodies to capsular polysaccharide, C-polysaccharide, and pneumolysin in paired sera were performed. The etiology was established in 64% of the patients. Streptococcus pneumoniae was the most common agent (32%).

    In a serological study of patients with pneumococcal infection, diagnosed by culture of CSF, TTA, or blood, IgG antibodies against C-polysaccharide and pneumolysin were determined by ELISA. The diagnostic sensitivity was only 51% and 60%, respectively.

    In conclusion, invasive pneumococcal disease is strongly overrepresented at tender and high age and in patients with concomitant conditions, notably alcoholism. S. pneumoniae remains a predominant causative agent of community-acquired pneumonia in adults needing hospitalization. Due to the low sensitivity and/or specificity of individual microbiological techniques, a combined use of several techniques is necessary when trying to assess the relative importance of pneumococci and other agents in pneumonia. Extended use of the currently available pneumococcal vaccine and development of improved pneumococcal vaccines seem highly warranted.

  • 53. Burman, Matthew
    et al.
    Nikolayenskyy, Vladyslav
    Kontsevaya, Irina
    Molina-Moya, Barbara
    Rzhepishevska, Olena
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Guglielmetti, Lorenzo
    Tackling the MDR-TB epidemic in Ukraine: every little helps … and much more needed2018In: Journal of Public Health, ISSN 2198-1833, E-ISSN 1613-2238, Vol. 40, no 1, p. 210-211Article in journal (Refereed)
  • 54.
    Byass, Peter
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Univ Witwatersrand, Fac Hlth Sci, Sch Publ Hlth, MRC Wits Rural Publ Hlth & Hlth Transit Res Unit, Johannesburg, South Africa.
    Interplay between childhood pneumonia and HIV infection2014In: Lancet. Infectious diseases (Print), ISSN 1473-3099, E-ISSN 1474-4457, Vol. 14, no 12, p. 1172-1173Article in journal (Refereed)
  • 55. Campos, Manuel
    et al.
    Cisneros, David A.
    Institut Pasteur, Molecular Genetics Unit, Department of Microbiology, 75015 Paris, France.
    Nivaskumar, Mangayarkarasi
    Francetic, Olivera
    The type II secretion system: a dynamic fiber assembly nanomachine2013In: Research in Microbiology, ISSN 0923-2508, E-ISSN 1769-7123, Vol. 164, no 6, p. 545-555Article in journal (Refereed)
    Abstract [en]

    Type II secretion systems (T2SSs) share common origins and structure with archaeal flagella (archaella) and pili, bacterial competence systems and type IV pili. All of these systems use a conserved ATP-powered machinery to assemble helical fibers that are anchored in the plasma membrane. The T2SSs assemble pseudopili, periplasmic filaments that promote extracellular secretion of folded periplasmic proteins. Comparative analysis of T2SSs and related fiber assembly nanomachines might provide important clues on their functional specificities and dynamics. This review focuses on recent developments in the study of pseudopilus structure and biogenesis, and discusses mechanistic models of pseudopilus function in protein secretion.

  • 56. Campos, Manuel
    et al.
    Nilges, Michaël
    Cisneros, David A.
    Institut Pasteur, Unité de Génétique Moléculaire, Département de Microbiologie, F-75015 Paris, France.
    Francetic, Olivera
    Detailed structural and assembly model of the type II secretion pilus from sparse data2010In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 107, no 29, p. 13081-13086Article in journal (Refereed)
    Abstract [en]

    Many gram-negative bacteria secrete specific proteins via the type II secretion systems (T2SS). These complex machineries share with the related archaeal flagella and type IV pilus (T4P) biogenesis systems the ability to assemble thin, flexible filaments composed of small, initially inner membrane-localized proteins called "pilins." In the T2SS from Klebsiella oxytoca, periplasmic pseudopili that are essential for pullulanase (PulA) secretion extend beyond the bacterial surface and form pili when the major pilin PulG is overproduced. Here, we describe the detailed, experimentally validated structure of the PulG pilus generated from crystallographic and electron microscopy data by a molecular modeling approach. Two intermolecular salt bridges crucial for function were demonstrated using single and complementary charge inversions. Double-cysteine substitutions in the transmembrane segment of PulG led to position-specific cross-linking of protomers in assembled pili. These biochemical data provided information on residue distances in the filament that were used to derive a refined model of the T2SS pilus at pseudoatomic resolution. PulG is organized as a right-handed helix of subunits, consistent with protomer organization in gonococcal T4P. The conserved character of residues involved in key hydrophobic and electrostatic interactions within the major pseudopilin family supports the general relevance of this model for T2SS pseudopilus structure.

  • 57.
    Carré, Helena
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Dermatology and Venerology.
    Lindström, Richard
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Dermatology and Venerology.
    Boman, Jens
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Janlert, Urban
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Lundqvist, Lotta
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Dermatology and Venerology.
    Nylander, Elisabet
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Dermatology and Venerology.
    Asking about condom use: a key to individualized care when screening for chlamydia2011In: International Journal of STD and AIDS (London), ISSN 0956-4624, E-ISSN 1758-1052, Vol. 22, no 8, p. 436-441Article in journal (Refereed)
    Abstract [en]

    Chlamydia trachomatis (CT) infection has been a target for both selective and national screening programmes, and Sweden has an opportunistic approach. A national plan of action states that risk groups should be identified and offered risk reduction counselling. Patients attending a drop-in sexually transmitted infection (STI) clinic reception at the University Hospital, Umeå, Sweden, were invited to complete a questionnaire regarding sociodemographic characteristics, symptoms and sexual risk behaviour; all had a CT test taken. A total of 1305 patients were included, 58% men, mean age 27.8 years. CT prevalence was 11%; 51% of those with CT were ≥ 25 years old. Only 5% used a condom during the entire sexual intercourse with their last new/temporary partner. Sexually active inconsistent condom users comprised 62% of the study population and contributed to 81% of the chlamydia infections. Asking whether a condom was used could quickly triage patients into groups with a 'higher risk' (none or inconsistent use of condoms and at least one new/temporary partners), and 'lower risk' (with more consistent condom use, although not always accurate) allowing for individualized care and counselling when screening for chlamydia. Evaluating whether a condom was used throughout the sexual intercourse did not add any useful information.

  • 58.
    Cava, Felipe
    et al.
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Kuru, Erkin
    Brun, Yves V.
    de Pedro, Miguel A.
    Modes of cell wall growth differentiation in rod-shaped bacteria2013In: Current Opinion in Microbiology, ISSN 1369-5274, E-ISSN 1879-0364, Vol. 16, no 6, p. 731-737Article in journal (Refereed)
    Abstract [en]

    A bacterial cell takes on the challenge to preserve and reproduce its shape at every generation against a substantial internal pressure by surrounding itself with a mechanical support, a peptidoglycan cell wall. The enlargement of the cell wall via net incorporation of precursors into the pre-existing wall conditions bacterial growth and morphology. However, generation, reproduction and/or modification of a specific shape requires that the incorporation takes place at precise locations for a defined time period. Much has been learnt in the past few years about the biochemistry of the peptidoglycan synthesis process, but topological approaches to the understanding of shape generation have been hindered by a lack of appropriate techniques. Recent technological advances are paving the way for substantial progress in understanding the mechanisms of bacterial morphogenesis. Here we review the latest developments, focusing on the impact of new techniques on the precise mapping of cell wall growth sites.

  • 59. Champion, Mia D
    et al.
    Zeng, Qiandong
    Nix, Eli B
    Nano, Francis E
    Keim, Paul
    Kodira, Chinnappa D
    Borowsky, Mark
    Young, Sarah
    Koehrsen, Michael
    Engels, Reinhard
    Pearson, Matthew
    Howarth, Clint
    Larson, Lisa
    White, Jared
    Alvarado, Lucia
    Forsman, Mats
    Totalförsvarets forskninginstitut, Umeå Sweden FOI.
    Bearden, Scott W
    Sjöstedt, Anders
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Titball, Richard
    Michell, Stephen L
    Birren, Bruce
    Galagan, James
    Comparative genomic characterization of Francisella tularensis strains belonging to low and high virulence subspecies2009In: PLoS pathogens, ISSN 1553-7374, Vol. 5, no 5, p. e1000459-Article in journal (Refereed)
    Abstract [en]

    Tularemia is a geographically widespread, severely debilitating, and occasionally lethal disease in humans. It is caused by infection by a gram-negative bacterium, Francisella tularensis. In order to better understand its potency as an etiological agent as well as its potential as a biological weapon, we have completed draft assemblies and report the first complete genomic characterization of five strains belonging to the following different Francisella subspecies (subsp.): the F. tularensis subsp. tularensis FSC033, F. tularensis subsp. holarctica FSC257 and FSC022, and F. tularensis subsp. novicida GA99-3548 and GA99-3549 strains. Here, we report the sequencing of these strains and comparative genomic analysis with recently available public Francisella sequences, including the rare F. tularensis subsp. mediasiatica FSC147 strain isolate from the Central Asian Region. We report evidence for the occurrence of large-scale rearrangement events in strains of the holarctica subspecies, supporting previous proposals that further phylogenetic subdivisions of the Type B clade are likely. We also find a significant enrichment of disrupted or absent ORFs proximal to predicted breakpoints in the FSC022 strain, including a genetic component of the Type I restriction-modification defense system. Many of the pseudogenes identified are also disrupted in the closely related rarely human pathogenic F. tularensis subsp. mediasiatica FSC147 strain, including modulator of drug activity B (mdaB) (FTT0961), which encodes a known NADPH quinone reductase involved in oxidative stress resistance. We have also identified genes exhibiting sequence similarity to effectors of the Type III (T3SS) and components of the Type IV secretion systems (T4SS). One of the genes, msrA2 (FTT1797c), is disrupted in F. tularensis subsp. mediasiatica and has recently been shown to mediate bacterial pathogen survival in host organisms. Our findings suggest that in addition to the duplication of the Francisella Pathogenicity Island, and acquisition of individual loci, adaptation by gene loss in the more recently emerged tularensis, holarctica, and mediasiatica subspecies occurred and was distinct from evolutionary events that differentiated these subspecies, and the novicida subspecies, from a common ancestor. Our findings are applicable to future studies focused on variations in Francisella subspecies pathogenesis, and of broader interest to studies of genomic pathoadaptation in bacteria.

  • 60.
    Chandra, Naresh
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Section of Virology. Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS). Umeå University.
    The glycobiology of human adenovirus infections: implications for tropism and treatment2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Human adenoviruses (HAdVs) are common human pathogens, causing gastrointestinal, ocular, and respiratory infections on a regular basis. Epidemic keratoconjunctivitis (EKC) is a severe ocular infection for which no approved antivirals are available. HAdV-D37 is one of the causative agents of EKC and uses sialic acid (SA)-containing glycans as cellular receptors. HAdV-D37 interacts with SA via the knob domain of the trimeric virus fiber protein, containing three SA-binding sites. HAdV-D37 also bind to glycosaminoglycans (GAGs), but the outcome of this interaction remains unknown. Here, using biochemical and cell-based assays, the impact of GAGs on HAdV-D37 infection (paper I) was investigated. We found that HAdV-D37 interacts with both soluble and cell-surface sulfated GAGs via the knob domain of the viral fiber protein. Remarkably, removal of heparan sulfate (HS; a type of GAG) from human corneal epithelial (HCE) cells by heparinase III enhanced HAdV-D37 infection. We propose that sulfated GAGs in bodily secretions and on plasma membranes function as decoy receptors that prevent the virus from binding to SA-containing receptors and inhibit subsequent virus infection. We also found abundant HS in the basement membrane of the human corneal epithelium. We suggest that this layer of HS functions as a barrier to sub-epithelial infection of HAdV-D37. Based on this finding, we hypothesized that GAG-mimetics may act as artificial decoy receptors and inhibit HAdV-D37 infection. Here, the antiviral effect of suramin (a known GAG-mimetic) and its analogs against HAdV-D37 (paper II) was evaluated. Interestingly, all compounds displayed antiviral effects by inhibiting the binding of HAdV-D37 to HCE cells. The antiviral effect of suramin was HAdV species-specific. We report for the first time that virus binding to cell-surface decoy receptor constitutes a potential target for antiviral drug development.

    HAdVs are the major cause of infectious conjunctivitis, constituting up to 75% of all conjunctivitis cases worldwide. Species B HAdV type 3 (HAdV-B3) causes pharyngoconjunctival fever (PCF), whereas HAdV-D8, -D37, and -D64 cause EKC. Recently, HAdV-D53, -D54, and -D56 have emerged as new EKC-causing agents. HAdV-E4 causes both PCF and EKC. SA-containing glycans have been established as cellular receptors for HAdV-D37. By means of cell-based assays, we investigated if ocular HAdVs other than HAdV-D37 also use SA-containing glycans as receptors on HCE cells (paper III). It was found that SA-containing glycans function as cellular receptors for five (HAdV-D8, -D37, -D53, -D54, and -D64) out of six EKC-causing species D HAdVs. We showed that these viruses interact with SAs via the knob domain of the viral fiber protein. HAdV-E4 and -D56 infection of cells was independent of SAs. Surprisingly, HCE cells were completely refractory to HAdV-B3 infection. A trivalent sialic acid (TSA) derivative ME0462 (compound 17a in paper II), designed to bind to SA-binding sites on HAdV-D37 fiber knob, also showed potent antiviral activity against several EKC-causing HAdVs. This suggests that ME0462 can be used as a broad-spectrum antiviral against known and emerging EKC-causing HAdVs. Surface plasmon resonance (SPR) analysis confirmed a direct interaction between ME0462 and fiber knobs of EKC-causing HAdVs.

    Recently, a TSA derivative (ME0322; designed to bind to SA-binding sites on HAdV-D37 fiber knob) was shown potent antiviral against HAdV-D37 in vitro. To improve the antiviral potency of this compound, six new TSA derivatives were synthesized and their inhibitory effects were evaluated against HAdV-D37 (paper IV). Interestingly, the best compound 17a was found approximately three orders of magnitude more potent (IC50 (binding) = 1.4 nM, IC50 (infection) = 2.9 nM) than ME0322 (IC50 in µM range). SPR data showed that HAdV-D37 fiber knob binds to TSA compounds with high affinities. Structural data revealed the trivalent binding mode of all newly synthesized TSA compounds to HAdV-D37 fiber knob. Ophthalmic toxicity of compound 17a (best compound) was also investigated in rabbits without any sign of toxicity.

    HAdV-D36 is a member of species D HAdV and has the ability to infect a broad range of animals, which is unusual for HAdVs. Another remarkable feature of HAdV-D36 is that this virus induces obesity in experimental animals. Several epidemiological studies highlighted a link between HAdV-D36 and human obesity. There is no information about the cellular receptor usage by HAdV-D36. Using structural biology and cell-based approaches, we investigated the cellular receptor(s) for HAdV-D36 (paper V).  We show that HAdV-D36 attaches to host cells (via the fiber knob) using the coxsackie and adenovirus receptor (CAR), SA-containing glycans, and one or more unknown proteins or glycoproteins. Using glycan microarray, we found that HAdV-D36 displays binding preference to a rare SA-variant: 4-O,5-N-diacetylneuraminic acid (Neu4,5Ac2), over the more common SA (in humans) i.e. 5-N-acetylneuraminic acid (Neu5Ac). Structural analysis of HAdV-D36 fiber knob:Neu4,5Ac2 complex explained this preference. To date, Neu4,5Achas not been detected in humans, although it is synthesized by many domestic and livestock animals. Our results indicate that HAdV-D36 has evolved to utilize a specialized set of cellular receptors that coincide with a unique host range and pathogenicity profile.

    These studies provide insights into multiple roles of glycans in HAdV infection cycle and highlight the therapeutic potential of glycans/glycan-mimetics in HAdV-D37 infection.

  • 61.
    Charpentier, Emmanuelle
    Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Programmable RNA-guided Cas9 endonuclease: a novel tool for genome engineering2014In: Transgenic research, ISSN 0962-8819, E-ISSN 1573-9368, Vol. 23, no 1, p. 188-189Article in journal (Other academic)
  • 62.
    Chorell, Erik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Pilicides and Curlicides: Design, synthesis, and evaluation of novel antibacterial agents targeting bacterial virulence2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    New strategies are needed to counter the growing problem of bacterial resistance to antibiotics. One such strategy is to design compounds that target bacterial virulence, which could work separately or in concert with conventional bacteriostatic or bactericidal antibiotics. Pilicides are a class of compounds based on a ring-fused 2-pyridone scaffold that target bacterial virulence by blocking the chaperone/usher pathway in E. coli and thereby inhibit the assembly of pili. This thesis describes the design, synthesis, and biological evaluation of compounds based on the pilicide scaffold with the goal of improving the pilicides and expanding their utility. Synthetic pathways have been developed to enable the introduction of substituents at the C-2 position of the pilicide scaffold. Biological evaluation of these compounds demonstrated that some C-2 substituents give rise to significant increases in potency. X-ray crystallography was used to elucidate the structural basis of this improved biological activity. Furthermore, improved methods for the preparation of oxygen-analogues and C-7 substituted derivatives of the pilicide scaffold have been developed. These new methods were used in combination with existing strategies to decorate the pilicide scaffold as part of a multivariate design approach to improve the pilicides and generate structure activity relationships (SARs).

    Fluorescent pilicides were prepared using a strategy where selected substituents were replaced with fluorophores having similar physicochemical properties as the original substituents. Many of the synthesized fluorescent compounds displayed potent pilicide activities and can thus be used to study the complex interactions between pilicide and bacteria. For example, when E. coli was treated with fluorescent pilicides, it was found that the compounds were not uniformly distributed throughout the bacterial population, suggesting that the compounds are primarily associated to bacteria with specific properties.

    Finally, by studying compounds designed to inhibit the aggregation of Aβ, it was found that some compounds based on the pilicide scaffold inhibit the formation of the functional bacterial amyloid fibers known as curli; these compounds are referred to as 'curlicides'. Some of the curlicides also prevent the formation of pili and thus exhibit dual pilicide-curlicide activity. The potential utility of such 'dual-action' compounds was highlighted by a study of one of the more potent dual pilicide-curlicides in a murine UTI model were the compound was found to significantly attenuate virulence in vivo.

  • 63.
    Chorell, Erik
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Bengtsson, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sainte-Luce Banchelin, Thomas
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Das, Pralay
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Uvell, Hanna
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sinha, Arun K
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Pinkner, Jerome S
    Department of Molecular Microbiology, Washington University, School of Medicine, St. Louis, Missouri 63110, USA.
    Hultgren, Scott J
    Department of Molecular Microbiology, Washington University, School of Medicine, St. Louis, Missouri 63110, USA.
    Almqvist, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Synthesis and application of a bromomethyl substituted scaffold to be used for efficient optimization of anti-virulence activity2011In: European Journal of Medicinal Chemistry, ISSN 0223-5234, E-ISSN 1768-3254, Vol. 46, no 4, p. 1103-1116Article in journal (Refereed)
    Abstract [en]

    Pilicides are a class of compounds that attenuate virulence in Gram negative bacteria by blocking the chaperone/usher pathway in Escherichia coli. It has also been shown that compounds derived from the peptidomimetic scaffold that the pilicides are based on can prevent both Aβ aggregation and curli formation. To facilitate optimizations towards the different targets, a new synthetic platform has been developed that enables fast and simple introduction of various substituents in position C-7 on the peptidomimetic scaffold. Importantly, this strategy also enables introduction of previously unattainable heteroatoms in this position. Pivotal to the synthetic strategy is the synthesis of a C-7 bromomethyl substituted derivative of the ring-fused dihydrothiazolo 2-pyridone pilicide scaffold. From this versatile and reactive intermediate various heteroatom-linked substituents could be introduced on the scaffold including amines, ethers, amides and sulfonamides. In addition, carbon-carbon bonds could be introduced to the sp(3)-hybridized bromomethyl substituted scaffold by Suzuki-Miyaura cross couplings. Evaluation of the 24 C-7 substituted compounds in whole-bacterial assays provided important structure-activity data and resulted in the identification of a number of new pilicides with activity as good or better than those developed previously.

  • 64.
    Chorell, Erik
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Pinkner, Jerome S.
    Department of Molecular Microbiology, Washington University, School of Medicine, St. Louis, Missouri 63110, USA.
    Bengtsson, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Edvinsson, Sofie
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Cusumano, Corinne K.
    Rosenbaum, Erik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Johansson, Lennart B-Å
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Hultgren, Scott J.
    Department of Molecular Microbiology, Washington University, School of Medicine, St. Louis, Missouri 63110, USA.
    Almqvist, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Design and synthesis of fluorescently labeled pilicides and curlicides: bioactive tools to study bacterial virulence mechanismsManuscript (preprint) (Other academic)
    Abstract [en]

    Pilicides and curlicides block formation of the E. coli virulence factors pili and curli. To facilitate studies of the interaction between these compounds and the pili and curli assembly systems, fluorescent pilicides and curlicides have been synthesized. This was achieved using a strategy where key pilicide and curlicide substituents were replaced by fluorophores having similar physicochemical properties. The resulting fluorescent compounds had improved anti-virulence activities as measured in pili- and curli-dependent biofilm assays. We created fluorescent pilicides and curlicides by introducing both coumarin and 4,4-Difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) fluorophores at two positions on the peptidomimetic pilicide and curlicide scaffold. Fluorescence images of the uropathogenic Escherichia coli (UPEC) strain UTI89 grown in the presence of these compounds shows that the compounds are strongly associated to the bacteria and seem to discriminate between different bacteria in a population.

  • 65.
    Cisneros, David A.
    et al.
    Unité de Génétique moléculaire, Départements de Microbiologie et Biologie Structurale et Chimie, Institut Pasteur, Paris, France.
    Bond, Peter J
    Pugsley, Anthony P
    Campos, Manuel
    Francetic, Olivera
    Minor pseudopilin self-assembly primes type II secretion pseudopilus elongation2012In: EMBO Journal, ISSN 0261-4189, E-ISSN 1460-2075, Vol. 31, no 4, p. 1041-1053Article in journal (Refereed)
    Abstract [en]

    In Gram-negative bacteria, type II secretion systems (T2SS) assemble inner membrane proteins of the major pseudopilin PulG (GspG) family into periplasmic filaments, which could drive protein secretion in a piston-like manner. Three minor pseudopilins PulI, PulJ and PulK are essential for protein secretion in the Klebsiella oxytoca T2SS, but their molecular function is unknown. Here, we demonstrate that together these proteins prime pseudopilus assembly, without actively controlling its length or secretin channel opening. Using molecular dynamics, bacterial two-hybrid assays, cysteine crosslinking and functional analysis, we show that PulI and PulJ nucleate filament assembly by forming a staggered complex in the plasma membrane. Binding of PulK to this complex results in its partial extraction from the membrane and in a 1-nm shift between their transmembrane segments, equivalent to the major pseudopilin register in the assembled PulG filament. This promotes fully efficient pseudopilus assembly and protein secretion. Therefore, we propose that PulI, PulJ and PulK self-assembly is thermodynamically coupled to the initiation of pseudopilus assembly, possibly setting the assembly machinery in motion.

  • 66.
    Cisneros, David A.
    et al.
    Molecular Genetics Unit, Department of Microbiology, Institut Pasteur, 75015, Paris, France; CNRS ERL3526, 75015 Paris, France..
    Pehau-Arnaudet, Gerard
    Francetic, Olivera
    Heterologous assembly of type IV pili by a type II secretion system reveals the role of minor pilins in assembly initiation2012In: Molecular Microbiology, ISSN 0950-382X, E-ISSN 1365-2958, Vol. 86, no 4, p. 805-818Article in journal (Refereed)
    Abstract [en]

    In Gram-negative bacteria, type IV pilus assembly (T4PS) and type II secretion (T2SS) systems polymerize inner membrane proteins called major pilins or pseudopilins respectively, into thin filaments. Four minor pilins are required in both systems for efficient fibre assembly. Escherichia coli K-12 has a set of T4PS assembly genes that are silent under standard growth conditions. We studied the heterologous assembly of the E. coli type IV pilin PpdD by the Klebsiella oxytoca T2SS called the Pul system. PpdD pilus assembly in this context depended on the expression of the K. oxytoca minor pseudopilin genes pulHIJK or of the E. coli minor pilin genes ppdAB-ygdB-ppdC. The E. coli minor pilins restored assembly of the major pseudopilin PulG in a pulHIJK mutant, but not the secretion of the T2SS substrate pullulanase. Thus, minor pilins and minor pseudopilins are functionally interchangeable in initiating major pilin assembly, further extending the fundamental similarities between the two systems. The data suggest that, in both systems, minor pilins activate the assembly machinery through a common self-assembly mechanism. When produced together, PulG and PpdD assembled into distinct homopolymers, establishing major pilins as key determinants of pilus elongation and structure.

  • 67. Cohen, Adam L
    et al.
    Sahr, Philip K
    Treurnicht, Florette
    Walaza, Sibongile
    Groome, Michelle J
    Kahn, Kathleen
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), School of Public Health; INDEPTH Network, Accra, Ghana .
    Dawood, Halima
    Variava, Ebrahim
    Tempia, Stefano
    Pretorius, Marthi
    Moyes, Jocelyn
    Olorunju, Steven A S
    Malope-Kgokong, Babatyi
    Kuonza, Lazarus
    Wolter, Nicole
    von Gottberg, Anne
    Madhi, Shabir A
    Venter, Marietjie
    Cohen, Cheryl
    Parainfluenza Virus Infection Among Human Immunodeficiency Virus (HIV)-Infected and HIV-Uninfected Children and Adults Hospitalized for Severe Acute Respiratory Illness in South Africa, 2009-20142015In: Open forum infectious diseases, ISSN 2328-8957, Vol. 2, no 4Article in journal (Refereed)
    Abstract [en]

    Background. Parainfluenza virus (PIV) is a common cause of acute respiratory tract infections, but little is known about PIV infection in children and adults in Africa, especially in settings where human immunodeficiency virus (HIV) prevalence is high. Methods. We conducted active, prospective sentinel surveillance for children and adults hospitalized with severe acute respiratory illness (SARI) from 2009 to 2014 in South Africa. We enrolled controls (outpatients without febrile or respiratory illness) to calculate the attributable fraction for PIV infection. Respiratory specimens were tested by multiplex real-time reverse-transcription polymerase chain reaction assay for parainfluenza types 1, 2, and 3. Results. Of 18 282 SARI cases enrolled, 1188 (6.5%) tested positive for any PIV type: 230 (19.4%) were type 1; 168 (14.1%) were type 2; 762 (64.1%) were type 3; and 28 (2.4%) had coinfection with 2 PIV types. After adjusting for age, HIV serostatus, and respiratory viral coinfection, the attributable fraction for PIV was 65.6% (95% CI [ confidence interval], 47.1-77.7); PIV contributed to SARI among HIV-infected and -uninfected children < 5 years of age and among individuals infected with PIV types 1 and 3. The observed overall incidence of PIV-associated SARI was 38 (95% CI, 36-39) cases per 100 000 population and was highest in children < 1 year of age (925 [ 95% CI, 864-989] cases per 100 000 population). Compared with persons without HIV, persons with HIV had an increased relative risk of PIV hospitalization (9.4; 95% CI, 8.5-10.3). Conclusions. Parainfluenza virus causes substantial severe respiratory disease in South Africa among children < 5 years of age, especially those that are infected with HIV.

  • 68. Cohen, Cheryl
    et al.
    Walaza, Sibongile
    Moyes, Jocelyn
    Groome, Michelle
    Tempia, Stefano
    Pretorius, Marthi
    Hellferscee, Orienka
    Dawood, Halima
    Chhagan, Meera
    Naby, Fathima
    Haffejee, Summaya
    Variava, Ebrahim
    Kahn, Kathleen
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Nzenze, Susan
    Tshangela, Akhona
    von Gottberg, Anne
    Wolter, Nicole
    Cohen, Adam L.
    Kgokong, Babatyi
    Venter, Marietjie
    Madhi, Shabir A.
    Epidemiology of Viral-associated Acute Lower Respiratory Tract Infection Among Children < 5 Years of Age in a High HIV Prevalence Setting, South Africa, 2009-20122015In: The Pediatric Infectious Disease Journal, ISSN 0891-3668, E-ISSN 1532-0987, Vol. 34, no 1, p. 66-72Article in journal (Refereed)
    Abstract [en]

    Background: Data on the epidemiology of viral-associated acute lower respiratory tract infection (LRTI) from high HIV prevalence settings are limited. We aimed to describe LRTI hospitalizations among South African children aged < 5 years. Methods: We prospectively enrolled hospitalized children with physician-diagnosed LRTI from 5 sites in 4 provinces from 2009 to 2012. Using polymerase chain reaction (PCR), nasopharyngeal aspirates were tested for 10 viruses and blood for pneumococcal DNA. Incidence was estimated at 1 site with available population denominators. Results: We enrolled 8723 children aged < 5 years with LRTI, including 64% < 12 months. The case-fatality ratio was 2% (150/8512). HIV prevalence among tested children was 12% (705/5964). The overall prevalence of respiratory viruses identified was 78% (6517/8393), including 37% rhinovirus, 26% respiratory syncytial virus (RSV), 7% influenza and 5% human metapneumovirus. Four percent (253/6612) tested positive for pneumococcus. The annual incidence of LRTI hospitalization ranged from 2530 to 3173/100,000 population and was highest in infants (8446-10532/100,000). LRTI incidence was 1.1 to 3.0-fold greater in HIV-infected than HIV-uninfected children. In multivariable analysis, compared to HIV-uninfected children, HIV-infected children were more likely to require supplemental-oxygen [odds ratio (OR): 1.3, 95% confidence interval (CI): 1.1-1.7)], be hospitalized > 7 days (OR: 3.8, 95% CI: 2.8-5.0) and had a higher case-fatality ratio (OR: 4.2, 95% CI: 2.6-6.8). In multivariable analysis, HIV-infection (OR: 3.7, 95% CI: 2.2-6.1), pneumococcal coinfection (OR: 2.4, 95% CI: 1.1-5.6), mechanical ventilation (OR: 6.9, 95% CI: 2.7-17.6) and receipt of supplemental-oxygen (OR: 27.3, 95% CI: 13.2-55.9) were associated with death. Conclusions: HIV-infection was associated with an increased risk of LRTI hospitalization and death. A viral pathogen, commonly RSV, was identified in a high proportion of LRTI cases.

  • 69. Cohen, Cheryl
    et al.
    Walaza, Sibongile
    Moyes, Jocelyn
    Groome, Michelle
    Tempia, Stefano
    Pretorius, Marthi
    Hellferscee, Orienka
    Dawood, Halima
    Haffejee, Summaya
    Variava, Ebrahim
    Kahn, Kathleen
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Tshangela, Akhona
    von Gottberg, Anne
    Wolter, Nicole
    Cohen, Adam L.
    Kgokong, Babatyi
    Venter, Marietjie
    Madhi, Shabir A.
    Epidemiology of Severe Acute Respiratory Illness (SARI) among Adults and Children Aged >= 5 Years in a High HIV-Prevalence Setting, 2009-20122015In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 2, article id e0117716Article in journal (Refereed)
    Abstract [en]

    Objective There are few published studies describing severe acute respiratory illness ( SARI) epidemiology amongst older children and adults from high HIV-prevalence settings. We aimed to describe SARI epidemiology amongst individuals aged >= 5 years in South Africa. Methods We conducted prospective surveillance for individuals with SARI from 2009-2012. Using polymerase chain reaction, respiratory samples were tested for ten viruses, and blood for pneumococcal DNA. Cumulative annual SARI incidence was estimated at one site with population denominators. Findings We enrolled 7193 individuals, 9% (621/7067) tested positive for influenza and 9%(600/6519) for pneumococcus. HIV-prevalence was 74% (4663/6334). Among HIV-infected individuals with available data, 41% of 2629 were receiving antiretroviral therapy (ART). The annual SARI hospitalisation incidence ranged from 325-617/100,000 population. HIV-infected individuals experienced a 13-19 times greater SARI incidence than HIV-uninfected individuals (p<0.001). On multivariable analysis, compared to HIV-uninfected individuals, HIV-infected individuals were more likely to be receiving tuberculosis treatment (odds ratio (OR): 1.7; 95% CI:1.1-2.7), have pneumococcal infection (OR 2.4; 95% CI: 1.7-3.3) be hospitalised for >7 days rather than <2 days (OR1.7; 95% CI: 1.2-2.2) and had a higher case-fatality ratio (8% vs 5%; OR1.7; 95% CI: 1.2-2.3), but were less likely to be infected with influenza (OR 0.6; 95% CI: 0.5-0.8). On multivariable analysis, independent risk indicators associated with death included HIV infection (OR 1.8; 95% CI: 1.3-2.4), increasing age-group, receiving mechanical ventilation (OR 6.5; 95% CI: 1.3-32.0) and supplemental-oxygen therapy (OR 2.6; 95% CI: 2.1-3.2). Conclusion The burden of hospitalized SARI amongst individuals aged >= 5 years is high in South Africa. HIV-infected individuals are the most important risk group for SARI hospitalization and mortality in this setting.

  • 70.
    Connolly-Andersen, Anne-Marie
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology. Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Hammargren, Edvin
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Whitaker, Heather
    Eliasson, Mats
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Holmgren, Lars
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Klingstrom, Jonas
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Increased Risk of Acute Myocardial Infarction and Stroke During Hemorrhagic Fever With Renal Syndrome A Self-Controlled Case Series Study2014In: Circulation, ISSN 0009-7322, E-ISSN 1524-4539, Vol. 129, no 12, p. 1295-1302Article in journal (Refereed)
    Abstract [en]

    Background We recently observed that cardiovascular causes of death are common in patients with hemorrhagic fever with renal syndrome (HFRS), which is caused by hantaviruses. However, it is not known whether HFRS is a risk factor for the acute cardiovascular events of acute myocardial infarction (AMI) and stroke. Methods and Results Personal identification numbers from the Swedish HFRS patient database (1997-2012; n=6643) were cross-linked with the National Patient Register from 1987 to 2011. Using the self-controlled case series method, we calculated the incidence rate ratio of AMI/stroke in the 21 days after HFRS against 2 different control periods either excluding (analysis 1) or including (analysis 2) fatal AMI/stroke events. The incidence rate ratios for analyses 1 and 2 for all AMI events were 5.53 (95% confidence interval [CI], 2.6-11.8) and 6.02 (95% CI, 2.95-12.3) and for first AMI events were 3.53 (95% CI, 1.25-9.96) and 4.64 (95% CI, 1.83-11.77). The incidence rate ratios for analyses 1 and 2 for all stroke events were 12.93 (95% CI, 5.62-29.74) and 15.16 (95% CI, 7.21-31.87) and for first stroke events were 14.54 (95% CI, 5.87-36.04) and 17.09 (95% CI, 7.49-38.96). The majority of stroke events occurred in the first week after HFRS. Seasonal effects were not observed, and apart from 1 study, neither sex nor age interacted with the associations observed in this study. Conclusions There is a significantly increased risk for AMI and stroke in the immediate time period after HFRS. Therefore, HFRS patients should be carefully monitored during the acute phase of disease to ensure early recognition of symptoms of impending AMI or stroke.

  • 71.
    Connolly-Andersen, Anne-Marie
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology. Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Sundberg, Erik
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Clinical chemistry. Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Hultdin, Johan
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Clinical chemistry.
    Baudin, Maria
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Larsson, Johanna
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Clinical chemistry.
    Dunne, Eimear
    Clinical Research Centre, Royal College of Surgeons in Ireland, Dublin .
    Kenny, Dermot
    Clinical Research Centre, Royal College of Surgeons in Ireland, Dublin .
    Lindahl, Tomas L.
    Department of Clinical and Experimental Medicine, Linköping University, Sweden.
    Ramström, Sofia
    Department of Clinical and Experimental Medicine, Linköping University, Sweden.
    Nilsson, Sofie
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Clinical chemistry.
    Increased Thrombopoiesis and Platelet Activation in Hantavirus-Infected Patients2015In: Journal of Infectious Diseases, ISSN 0022-1899, E-ISSN 1537-6613, Vol. 212, no 7, p. 1061-1069Article in journal (Refereed)
    Abstract [en]

    Background. Thrombocytopenia is a common finding during viral hemorrhagic fever, which includes hemorrhagic fever with renal syndrome (HFRS). The 2 main causes for thrombocytopenia are impaired thrombopoiesis and/or increased peripheral destruction of platelets. In addition, there is an increased intravascular coagulation risk during HFRS, which could be due to platelet activation. Methods. Thrombopoiesis was determined by quantification of platelet counts, thrombopoietin, immature platelet fraction, and mean platelet volume during HFRS. The in vivo platelet activation was determined by quantification of soluble P-selectin (sP-selectin) and glycoprotein VI (sGPVI). The function of circulating platelets was determined by ex vivo stimulation followed by flow cytometry analysis of platelet surface-bound fibrinogen and P-selectin exposure. Intravascular coagulation during disease was determined by scoring for disseminated intravascular coagulation (DIC) and recording thromboembolic complications. Results. The levels of thrombopoietin, immature platelet fraction, and mean platelet volume all indicate increased thrombopoiesis during HFRS. Circulating platelets had reduced ex vivo function during disease compared to follow-up. Most interestingly, we observed significantly increased in vivo platelet activation in HFRS patients with intravascular coagulation (DIC and thromboembolic complications) as shown by sP-selectin and sGPVI levels. Conclusions. HFRS patients have increased thrombopoiesis and platelet activation, which contributes to intravascular coagulation.

  • 72.
    Connolly-Andersen, Anne-Marie
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Whitaker, Heather
    Klingstrom, Jonas
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Risk of venous thromboembolism following hemorrhagic fever with renal syndrome: a self-controlled case series study2018In: Clinical Infectious Diseases, ISSN 1058-4838, E-ISSN 1537-6591, Vol. 66, no 2, p. 268-273Article in journal (Refereed)
    Abstract [en]

    Background: Bleeding is associated with viral hemorrhagic fevers; however, thromboembolic complications have received less attention. Hemorrhagic fever with renal syndrome (HFRS) is a mild viral hemorrhagic fever caused by Puumala hantavirus. We previously identified HFRS as a risk factor for myocardial infarction and stroke, but the risk for venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), is unknown.

    Methods: Personal identity numbers from the Swedish HFRS database were cross-linked with the National Patient register to obtain information on all causes for hospitalization during 1964 to 2013. The self-controlled case series method was used to calculate the incidence rate ratio (IRR) for first VTE, DVT, and PE during 1998 to 2013.

    Results: From 7244 HFRS patients, there were 146 with a first VTE of which 74 were DVT and 78 were PE, and 6 patients had both DVT and PE. The overall risk for a VTE was significantly higher during the first 2 weeks following HFRS onset, with an IRR of 64.3 (95% confidence interval [CI], 36.3-114). The corresponding risk for a DVT was 45.9 (95% CI, 18-117.1) and for PE, 76.8 (95% CI, 37.1-159). Sex interacted significantly with the association between HFRS and VTE, with females having a higher risk compared with males.

    Conclusions: A significantly increased risk for VTE was found in the time period following HFRS onset. It is important to keep this in mind and monitor HFRS patients, and possibly other viral hemorrhagic fever patients, for early symptoms of VTE.

  • 73.
    Connolly-Andersson, Anne-Marie
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Ahlm, Kristin
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Forensic Medicine.
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Klingström, Jonas
    Puumala virus infections associated with cardiovascular causes of death2013In: Emerging Infectious Diseases, ISSN 1080-6040, E-ISSN 1080-6059, Vol. 19, no 1, p. 126-128Article in journal (Refereed)
    Abstract [en]

    We studied the causes of death of patients in Sweden with diagnoses of hemorrhagic fever with renal syndrome (HFRS) during 1997–2009. Cardiovascular disorders were a common cause of death during acute-phase HFRS and were the cause of death for >50% of those who died during the first year after HFRS.

  • 74. Cupelli, Karolina
    et al.
    Müller, Steffen
    Persson, David B
    Jost, Marco
    Arnberg, Niklas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology. Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Stehle, Thilo
    Structure of adenovirus type 21 knob in complex with CD46 reveals key differences in receptor contacts among species B adenoviruses2010In: Journal of Virology, ISSN 0022-538X, E-ISSN 1098-5514, Vol. 84, no 7, p. 3189-3200Article in journal (Refereed)
    Abstract [en]

    The complement regulation protein CD46 is the primary attachment receptor for most species B adenoviruses (Ads). However, significant variability exists in sequence and structure among species B Ads in the CD46-binding regions, correlating with differences in affinity. Here, we report a structure-function analysis of the interaction of the species B Ad21 knob with the two N-terminal repeats SCR1 and SCR2 of CD46, CD46-D2. We have determined the structures of the Ad21 knob in its unliganded form as well as in complex with CD46-D2, and we compare the interactions with those observed for the Ad11 knob-CD46-D2 complex. Surface plasmon resonance measurements demonstrate that the affinity of Ad21 knobs for CD46-D2 is 22-fold lower than that of the Ad11 knob. The superposition of the Ad21 and Ad11 knob structures in complex with CD46-D2 reveals a substantially different binding mode, providing an explanation for the weaker binding affinity of the Ad21 knob for its receptor. A critical difference in both complex structures is that a key interaction point, the DG loop, protrudes more in the Ad21 knob than in the Ad11 knob. Therefore, the protruding DG loop does not allow CD46-D2 to approach the core of the Ad21 knob as closely as in the Ad11 knob-CD46-D2 complex. In addition, the engagement of CD46-D2 induces a conformational change in the DG loop in the Ad21 knob but not in the Ad11 knob. Our results contribute to a more profound understanding of the CD46-binding mechanism of species B Ads and have relevance for the design of more efficient gene delivery vectors.

  • 75.
    Drobni, Mirva
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, Cariology.
    Li, Tong
    Umeå University, Faculty of Medicine, Department of Odontology, Cariology.
    Krüger, Karina
    Loimaranta, Vuokko
    Umeå University, Faculty of Medicine, Department of Odontology, Cariology.
    Kilian, Mogens
    Hammarström, Lennart
    Jörnvall, Hans
    Bergman, Tomas
    Strömberg, Nicklas
    Umeå University, Faculty of Medicine, Department of Odontology, Cariology.
    A host-derived pentapeptide enhancing host-bacteria commensalisms and communication2006In: Infection and Immunity, ISSN 0019-9567, E-ISSN 1098-5522, Vol. 74, no 11, p. 6293-6299Article in journal (Refereed)
    Abstract [en]

    Salivary proline-rich proteins (PRPs) attach commensal Actinomyces and Streptococcus species to teeth. Here, gel filtration, mass spectrometry and Edman degradation were applied to show the release of a pentapeptide, RGRPQ, from PRP-1 upon proteolysis by Streptococcus gordond. Moreover, synthetic RGRPQ and derivatives were used to investigate associated innate properties and responsible motifs. The RGRPQ peptide increased 2.5-fold the growth rate of S. gordonii via a Q-dependent sequence motif and selectively stimulated oral colonization of this organism in a rat model in vivo. In contrast, the growth of Streptococcus mutans, implicated in caries, was not affected. While the entire RGRPQ sequence was required to block sucrose-induced pH-decrease by S. gordonii and S. mutans, the N-terminal Arg residue mediated the pH increase (i.e., ammonia production) by S. gordonii alone (which exhibits Arg catabolism to ammonia). Strains of commensal viridans streptococci exhibited PR-P degradation and Arg catabolism, whereas cariogenic species did not. The RGRPQ peptide mediated via a differential Q-dependent sequence motif, adhesion inhibition, and desorption of PRP-1-binding strains of A. naeslundii genospecies 2 (5 of 10 strains) but not of S. gordonii (n = 5). The inhibitable A. naeslundii strains alone displayed the same binding profile as S. gordond to hybrid peptides terminating in RGRPQ or GQSPQ, derived from the middle or C-terminal segments of PRP-1. The present findings indicate the presence of a host-bacterium interaction in which a host peptide released by bacterial proteolysis affects key properties in biofilm formation.

  • 76. Dudnyk, Andrii
    et al.
    Rzhepishevska, Olena
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Rogach, Kostiantyn
    Kutsyna, Galyna
    Lange, Christoph
    Multidrug-resistant tuberculosis in Ukraine at a time of military conflict2015In: The International Journal of Tuberculosis and Lung Disease, ISSN 1027-3719, E-ISSN 1815-7920, Vol. 19, no 4, p. 492-493Article in journal (Refereed)
  • 77.
    Duperthuy, Marylise
    et al.
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Sjöström, Annika E.
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Sabharwal, Dharmesh
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Damghani, Fatemeh
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Uhlin, Bernt Eric
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Wai, Sun Nyunt
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Role of the Vibrio cholerae Matrix Protein Bap1 in Cross-Resistance to Antimicrobial Peptides2013In: PLoS Pathogens, ISSN 1553-7366, E-ISSN 1553-7374, Vol. 9, no 10, p. e1003620-Article in journal (Refereed)
    Abstract [en]

    Outer membrane vesicles (OMVs) that are released from Gram-negative pathogenic bacteria can serve as vehicles for the translocation of effectors involved in infectious processes. In this study we have investigated the role of OMVs of the Vibrio cholerae O1 El Tor A1552 strain in resistance to antimicrobial peptides (AMPs). To assess this potential role, we grew V. cholerae with sub-lethal concentrations of Polymyxin B (PmB) or the AMP LL-37 and analyzed the OMVs produced and their effects on AMP resistance. Our results show that growing V. cholerae in the presence of AMPs modifies the protein content of the OMVs. In the presence of PmB, bacteria release OMVs that are larger in size and contain a biofilm-associated extracellular matrix protein (Bap1). We demonstrated that Bap1 binds to the OmpT porin on the OMVs through the LDV domain of OmpT. In addition, OMVs from cultures incubated in presence of PmB also provide better protection for V. cholerae against LL-37 compared to OMVs from V. cholerae cultures grown without AMPs or in presence of LL-37. Using a bap1 mutant we showed that cross-resistance between PmB and LL-37 involved the Bap1 protein, whereby Bap1 on OMVs traps LL-37 with no subsequent degradation of the AMP.

  • 78.
    Edin, Alicia
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Improved diagnosis and prediction of community-acquired pneumonia2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Community-acquired pneumonia (CAP) is a major cause of morbidity and mortality worldwide. Although there is wide variation in the microbial etiology, CAP may manifest with similar symptoms, making institution of proper treatment challenging. Therefore, etiological diagnosis is important to ensure that correct treatment and necessary infection control measures are instituted. This provides a challenge for conventional microbial diagnostic methods, typically based on culture and direct antigen tests. Moreover, existing molecular biomarkers have poor prognostic value. Few studies have investigated the global metabolic response during infection and virtually nothing is known about early responses after the start of antimicrobial treatment. The aim of this work was to improve diagnostic and predictive methods for CAP.

    In paper I, a qPCR panel targeting 15 pathogens known to cause CAP was developed and evaluated. It combined identification of bacterial pathogens and viruses in the same diagnostic platform. The method proved to be robust and the results consistent with those obtained by standard methods. The panel approach, compared to conventional, selective diagnostics, detected a larger number of pathogens. In Paper II, whole blood samples from 65 patients with bacteremic sepsis were analyzed for metabolite profiles. Forty-nine patients with symptoms of sepsis, but later attributed to other diagnoses, were matched according to age and sex and served as a control group. Six metabolites were identified, all of which predicted growth of bacteria in blood culture. One of the metabolites, myristic acid, alone predicted bacteremic sepsis with a sensitivity of 100% and a specificity of 95%. Paper III and IV were based on a clinical study enrolling 35 patients with suspected CAP in need of hospital care. The aim was to study the metabolic response during the early phase of acute infection. The qPCR panel developed in Paper I was used to obtain the microbial etiological diagnosis. Paper IV focused on the global metabolic response and highlighted the dynamics of changes in major metabolic pathways during early recovery. A specific metabolite pattern for M. pneumoniae etiology was found. Four metabolites accurately predicted all but one patient as either M. pneumoniae etiology or not. Paper III looked at phospholipid levels during the first 48 hours after hospital admission. It was found that all major phospholipid species, especially the lysophosphatidyl-cholines, were pronouncedly decreased during acute infection. Levels started to increase the day after admission, reaching statistical significance at 48 hours. Paper II-IV showed that metabolomics might be used to study a number of different aspects of infection, such as etiology, disease progress and recovery. Knowledge of the metabolic profiles of patients may not only be utilized for biomarker discovery, as proposed in this work, but also for the future development of targeted therapies and supportive treatment.

  • 79.
    Edin, Alicia
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology. Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Kauppi, Anna M.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology. Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Müller, Daniel C.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology. Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Gylfe, Åsa
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology. Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Sjöstedt, Anders
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology. Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Johansson, Anders F.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology. Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Metabolomic Analysis of Sera from Patients with Community-Acquired PneumoniaManuscript (preprint) (Other academic)
  • 80.
    Edvinsson, Benjamin
    et al.
    Centre for Microbiological Preparedness, Swedish Institute for Infectious Diseases Control.
    Lappalainen, Maija
    Laboratory Services, Dept Virology, Helsiniki University.
    Anttila, Veli-Jukka
    Div Internal Medicine, Dept Infectious Diseases, Helsinki University.
    Paetau, Anders
    Dept Pathology, Helsinki University.
    Evengård, Birgitta
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Toxoplasmosis in immunocompromized patients2009In: Scandinavian Journal of Infectious Diseases, ISSN 0036-5548, E-ISSN 1651-1980, Vol. 41, no 5, p. 368-371Article in journal (Refereed)
    Abstract [en]

    Infection with the cosmopolitan parasite Toxoplasma gondii is often associated with severe consequences and a high mortality rate in immunocompromized patients. Non-specific symptoms make diagnosis challenging. Monitoring of patients at risk is of value. We here present 8 cases of toxoplasmosis in immunocompromized patients with suggestions for preventive monitoring.

  • 81.
    Elgh, Fredrik
    Patologkliniken, Universitetssjukhuset i Örebro; institutionen för klinisk medicin, Hälsoakademin, Örebro universitet.
    Heltäckande översikt om humaninfektioner orsakade av fågelinfluensa2008In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 105, no 20, p. 1470-1471Article in journal (Refereed)
  • 82.
    Elgh, Fredrik
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Influensapandemiers påverkan på samhället; nödvändig erfarenhetsbakgrund för pandemiplanering2007In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 8, no 104, p. 614-619Article in journal (Refereed)
  • 83.
    Elgh, Fredrik
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Tegnell, Anders
    [The Spanish influenza virus aroused from the dead]2006In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 103, no 24-25, p. 1937-1940Article in journal (Other academic)
  • 84. Elmwall, Jonas
    et al.
    Kwiecinski, Jakub
    Na, Manli
    Ali, Abukar Ahmed
    Osla, Veronica
    Shaw, Lindsey N.
    Wang, Wanzhong
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Sävman, Karin
    Josefsson, Elisabet
    Bylund, Johan
    Jin, Tao
    Welin, Amanda
    Karlsson, Anna
    Galectin-3 Is a Target for Proteases Involved in the Virulence of Staphylococcus aureus2017In: Infection and Immunity, ISSN 0019-9567, E-ISSN 1098-5522, Vol. 85, no 7, article id e00177-17Article in journal (Refereed)
    Abstract [en]

    Staphylococcus aureus is a major cause of skin and soft tissue infection. The bacterium expresses four major proteases that are emerging as virulence factors: aureolysin (Aur), V8 protease (SspA), staphopain A (ScpA), and staphopain B (SspB). We hypothesized that human galectin-3, a beta-galactoside-binding lectin involved in immune regulation and antimicrobial defense, is a target for these proteases and that proteolysis of galectin-3 is a novel immune evasion mechanism. Indeed, supernatants from laboratory strains and clinical isolates of S. aureus caused galectin-3 degradation. Similar proteolytic capacities were found in Staphylococcus epidermidis isolates but not in Staphylococcus saprophyticus. Galectin-3-induced activation of the neutrophil NADPH oxidase was abrogated by bacterium-derived proteolysis of galectin-3, and SspB was identified as the major protease responsible. The impact of galectin-3 and protease expression on S. aureus virulence was studied in a murine skin infection model. In galectin-3 (+)/(+) mice, SspB-expressing S. aureus caused larger lesions and resulted in higher bacterial loads than protease-lacking bacteria. No such difference in bacterial load or lesion size was detected in galectin-3 (+)/(+) mice, which overall showed smaller lesion sizes than the galectin-3 (+)/(+) animals. In conclusion, the staphylococcal protease SspB inactivates galectin-3, abrogating its stimulation of oxygen radical production in human neutrophils and increasing tissue damage during skin infection.

  • 85.
    Engdahl, Cecilia
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Näslund, Jonas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Lindgren, Lena
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Bucht, Göran
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    The Rift Valley Fever virus protein NSm and putative cellular protein interactions2012In: Virology Journal, ISSN 1743-422X, Vol. 9, p. 139-Article in journal (Refereed)
    Abstract [en]

    Rift Valley Fever is an infectious viral disease and an emerging problem in many countries of Africa and on the Arabian Peninsula. The causative virus is predominantly transmitted by mosquitoes and high mortality and abortion rates characterize outbreaks in animals while symptoms ranging from mild to life-threatening encephalitis and hemorrhagic fever are noticed among infected humans. For a better prevention and treatment of the infection, an increased knowledge of the infectious process of the virus is required. The focus of this work was to identify protein-protein interactions between the non-structural protein (NSm), encoded by the M-segment of the virus, and host cell proteins. This study was initiated by screening approximately 26 million cDNA clones of a mouse embryonic cDNA library for interactions with the NSm protein using a yeast two-hybrid system. We have identified nine murine proteins that interact with NSm protein of Rift Valley Fever virus, and the putative protein-protein interactions were confirmed by growth selection procedures and beta-gal activity measurements. Our results suggest that the cleavage and polyadenylation specificity factor subunit 2 (Cpsf2), the peptidyl-prolyl cistrans isomerase (cyclophilin)-like 2 protein (Ppil2), and the synaptosome-associated protein of 25 kDa (SNAP-25) are the most promising targets for the NSm protein of the virus during an infection.

  • 86.
    Engström, Patrik
    et al.
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Bailey, Leslie
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Önskog, Thomas
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Bergström, Sven
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Johansson, Jörgen
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    A comparative study of RNA and DNA as internal gene expression controls early in the developmental cycle of Chlamydia pneumoniae2010In: FEMS Immunology and Medical Microbiology, ISSN 0928-8244, E-ISSN 1574-695X, Vol. 58, no 2, p. 244-253Article in journal (Refereed)
    Abstract [en]

    Many microbial pathogens invade and proliferate within host cells and the molecular mechanism underlying this behavior is currently being revealed for several bacterial species. Testing clinically relevant antibacterial compounds and elucidating their effects on gene expression requires adequate controls, especially when studying genetically intractable organisms such as Chlamydia spp., for which various gene fusions cannot be constructed. Until now, relative mRNA levels in Chlamydia have been measured using different internal gene expression controls, including 16S rRNA, mRNAs, and DNA. Here, we compared the advantages and disadvantages of various internal expression controls during the early phase of Chlamydia pneumoniae development. The relative abundance of target mRNAs varied using the different internal control RNAs. This was partly due to variation in the transcript stability of the RNA species. Also, seven out of nine of the analyzed RNAs increased fivefold or more between 2 and 14 h postinfection, while the amount of DNA and number of cells remained essentially unaltered. Our results suggest that RNA should not be used as a gene expression control during the early phase of Chlamydia development, and that intrinsic bacterial DNA is preferable for that purpose because it is stable, abundant, and its relative amount is generally correlated with bacterial numbers.

  • 87.
    Eriksson, Axel
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine. Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Increased incidence of inflammatory bowel disease after the outbreak of Cryptosporidium hominis in Östersund? - Data from the Swedish Quality Registry for inflammatory bowel disease, SWIBREG2018Independent thesis Basic level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 88. Ermert, David
    et al.
    Zychlinsky, Arturo
    Urban, Constantin
    Fungal and bacterial killing by neutrophils2009In: Host-Pathogen Interactions: Methods and Protocols / [ed] Steffen Rupp, Kai Sohn, Humana Press, 2009, Vol. 470, p. 293-312Chapter in book (Refereed)
    Abstract [en]

    Neutrophils are professional phagocytes of the innate immune system that are essential to control bacterial and fungal infections. These cells engulf and kill invading microbes. Additionally, activated neutrophils are able to release neutrophil extracellular traps (NETs). These fibers consist of chromatin decorated with antimicrobial proteins to trap and kill microbes. Appropriate quantitative methods are required to understand the nature of interactions of neutrophils with pathogens. Here we present assays to measure killing mediated by phagocytosis, by NETs, by a combination of both, and by granular extract. As examples, we use Candida albicans for fungal and Shigella flexneri for bacterial pathogens.

  • 89.
    Evengård, Birgitta
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Marcinkute, Audrone
    Petersen, Eskild
    Northern Europe2011In: A geographic guide to infectious diseases / [ed] Petersen E, Chen LH, Schlaugenhof P, John Wiley & Sons, 2011, 1, p. 218-229Chapter in book (Refereed)
    Abstract [en]

    The most common community-acquired infectious diseases are upper and lower respiratory tract infections, gastroenteritis, and urinary tract infections. Among vector-borne infections, Borrelia dominate but tick-borne encephalitis is found in the Baltic countries and parts of Sweden and a few cases have been reported from Denmark. The most common cause of viral meningitis is enterovirus, and herpes virus is the most common cause of encephalitis. Bacterial meningitis is rare and the most common causes are pneumococci and meningococci type B. Hepatitis A is very rare but local outbreaks are described from single imported cases. Hepatitis B is often sexually transmitted and B and C are usually related to intravenous drug abuse. Gastroenteritis due to virus is seen and food-borne outbreaks are rare but seen regularly due to virus and especially Campylobacter and Salmonella spp. (Campylobacter, the most reported in Sweden.) The prevalence of HIV is below 1% in the population and all patients are offered free antiretroviral treatment. Infections related to immunosuppressed patients like transplant recipients and patients for other reasons receiving immunosuppressive treatment are increasing primarily due to an increasingly aging population. Tuberculosis is still common in the Baltic countries where MDR is also a problem. Parasitic infections are rare, but waterborne outbreaks of Giardia have been described from Norway and Sweden. In the Baltic countries Echinococcus multilocularis seems to be spreading and Trichinella infections from consumption of infected meat has been described.

  • 90.
    Fahlgren, Anna
    et al.
    Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Avican, Kemal
    Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Westermark, Linda
    Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS). Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Nordfelth, Roland
    Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Fällman, Maria
    Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS). Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Colonization of cecum is important for development of persistent infection by Yersinia pseudotuberculosis2014In: Infection and Immunity, ISSN 0019-9567, E-ISSN 1098-5522, Vol. 82, no 8, p. 3471-3482Article in journal (Refereed)
    Abstract [en]

    Yersiniosis is a human disease caused by the bacterium Yersinia pseudotuberculosis or Yersinia enterocolitica. The infection is usually resolved but can lead to postinfectious sequelae, including reactive arthritis and erythema nodosum. The commonly used Yersinia mouse infection model mimics acute infection in humans to some extent but leads to systemic infection and eventual death. Here, we analyzed sublethal infection doses of Y. pseudotuberculosis in mice in real time using bioluminescent imaging and found that infections using these lower doses result in extended periods of asymptomatic infections in a fraction of mice. In a search for the site for bacterial persistence, we found that the cecum was the primary colonization site and was the site where the organism resided during a 115-day infection period. Persistent infection was accompanied by sustained fecal shedding of cultivable bacteria. Cecal patches were identified as the primary site for cecal colonization during persistence. Y. pseudotuberculosis bacteria were present in inflammatory lesions, in localized foci, or as single cells and also in neutrophil exudates in the cecal lumen. The chronically colonized cecum may serve as a reservoir for dissemination of infection to extraintestinal sites, and a chronic inflammatory state may trigger the onset of postinfectious sequelae. This novel mouse model for bacterial persistence in cecum has potential as an investigative tool to unveil a deeper understanding of bacterial adaptation and host immune defense mechanisms during persistent infection.

  • 91. Fearon, Elizabeth
    et al.
    Wiggins, Richard D.
    Pettifor, Audrey E.
    MacPhail, Catherine
    Kahn, Kathleen
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Medical Research Council/Wits University Rural Public Health and Health Transitions Research Unit (Agincourt), School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; INDEPTH Network, Accra, Ghana.
    Selin, Amanda
    Gómez-Olivé, F. Xavier
    Delany-Moretlwe, Sinéad
    Piwowar-Manning, Estelle
    Laeyendecker, Oliver
    Hargreaves, James R.
    Associations between friendship characteristics and HIV and HSV-2 status amongst young South African women in HPTN-0682017In: Journal of the International AIDS Society, ISSN 1758-2652, E-ISSN 1758-2652, Vol. 20, article id e25029Article in journal (Refereed)
    Abstract [en]

    Introduction: Prevalence of HIV among young women in South Africa remains extremely high. Adolescent peer groups have been found to be an important influence on a range of health behaviours. The characteristics of young women's friendships might influence their sexual health and HIV risk via connections to sexual partners, norms around sexual initiation and condom use, or provision of social support. We investigated associations between young women's friendships and their Herpes Simplex Virus Type 2 (HSV-2) and HIV infection status in rural South Africa. Methods: Our study is a cross-sectional, egocentric network analysis. In 2011 to 2012, we tested 13- to 20-year-old young women for HIV and HSV-2, and collected descriptions of five friendships for each. We generated summary measures describing friend socio-demographic characteristics and the number of friends perceived to have had sex. We used logistic regression to analyse associations between friend characteristics and participant HIV and HSV-2 infection, excluding likely perinatal HIV infections. Results: There were 2326 participants included in the study sample, among whom HIV and HSV-2 prevalence were 3.3% and 4.6% respectively. Adjusted for participant and friend socio-demographic characteristics, each additional friend at least one year older than the participant was associated with raised odds of HIV (odds ratio (OR)=1.37, 95% CI 1.03 to 1.82) and HSV-2 (adjusted OR=1.41, 95% CI 1.18 to 1.69). Each additional friend perceived to have ever had sex also raised the odds of HIV (OR=1.29, 95% CI 1.03 to 1.63) and HSV-2 (OR=1.18, 95% CI 1.03 to 1.35). Discussion: We found good evidence that a greater number of older friends and friends perceived to have had sex were associated with increased risk for HSV-2 and HIV infection among young women. Conclusions: The characteristics of young women's friendships could contribute to their risk of HIV infection. The extent to which policies or programmes influence age-mixing and young women's normative environments should be considered.

  • 92. Flentie, Kelly
    et al.
    Harrison, Gregory A.
    Tükenmez, Hasan
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Livny, Jonathan
    Good, James A. D.
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Sarkar, Souvik
    Zhu, Dennis X.
    Kinsella, Rachel L.
    Weiss, Leslie A.
    Solomon, Samantha D.
    Schene, Miranda E.
    Hansen, Mette R.
    Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR). Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Cairns, Andrew G.
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Kulén, Martina
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Wixe, Torbjörn
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Lindgren, Anders E. G.
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Chorell, Erik
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR). Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110.
    Bengtsson, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Krishnan, K. Syam
    Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR). Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Hultgren, Scott J.
    Larsson, Christer
    Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology). Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Almqvist, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Stallings, Christina L.
    Chemical disarming of isoniazid resistance in Mycobacterium tuberculosis2019In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 116, no 21, p. 10510-10517Article in journal (Refereed)
    Abstract [en]

    Mycobacterium tuberculosis (Mtb) killed more people in 2017 than any other single infectious agent. This dangerous pathogen is able to withstand stresses imposed by the immune system and tolerate exposure to antibiotics, resulting in persistent infection. The global tuberculosis (TB) epidemic has been exacerbated by the emergence of mutant strains of Mtb that are resistant to frontline antibiotics. Thus, both phenotypic drug tolerance and genetic drug resistance are major obstacles to successful TB therapy. Using a chemical approach to identify compounds that block stress and drug tolerance, as opposed to traditional screens for compounds that kill Mtb, we identified a small molecule, C10, that blocks tolerance to oxidative stress, acid stress, and the frontline antibiotic isoniazid (INH). In addition, we found that C10 prevents the selection for INH-resistant mutants and restores INH sensitivity in otherwise INH-resistant Mtb strains harboring mutations in the katG gene, which encodes the enzyme that converts the prodrug INH to its active form. Through mechanistic studies, we discovered that C10 inhibits Mtb respiration, revealing a link between respiration homeostasis and INH sensitivity. Therefore, by using C10 to dissect Mtb persistence, we discovered that INH resistance is not absolute and can be reversed.

  • 93. Fontana, Robert J.
    et al.
    Brown, Robert S., Jr.
    Moreno-Zamora, Ana
    Prieto, Martin
    Joshi, Shobha
    Londono, Maria-Carlota
    Herzer, Kerstin
    Chacko, Kristina R.
    Stauber, Rudolf E.
    Knop, Viola
    Jafri, Syed-Mohammed
    Castells, Lluis
    Ferenci, Peter
    Torti, Carlo
    Durand, Christine M.
    Loiacono, Laura
    Lionetti, Raffaella
    Bahirwani, Ranjeeta
    Weiland, Ola
    Mubarak, Abdullah
    ElSharkawy, Ahmed M.
    Stadler, Bernhard
    Montalbano, Marzia
    Berg, Christoph
    Pellicelli, Adriano M.
    Stenmark, Stephan
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Vekeman, Francis
    Ionescu-Ittu, Raluca
    Emond, Bruno
    Reddy, K. Rajender
    Daclatasvir combined with sofosbuvir or simeprevir in liver transplant recipients with severe recurrent hepatitis C infection2016In: Liver transplantation, ISSN 1527-6465, E-ISSN 1527-6473, Vol. 22, no 4, p. 446-458Article in journal (Refereed)
    Abstract [en]

    Daclatasvir (DCV) is a potent, pangenotypic nonstructural protein 5A inhibitor with demonstrated antiviral efficacy when combined with sofosbuvir (SOF) or simeprevir (SMV) with or without ribavirin (RBV) in patients with chronic hepatitis C virus (HCV) infection. Herein, we report efficacy and safety data for DCV-based all-oral antiviral therapy in liver transplantation (LT) recipients with severe recurrent HCV. DCV at 60mg/day was administered for up to 24 weeks as part of a compassionate use protocol. The study included 97 LT recipients with a mean age of 59.3 +/- 8.2 years; 93% had genotype 1 HCV and 31% had biopsy-proven cirrhosis between the time of LT and the initiation of DCV. The mean Model for End-Stage Liver Disease (MELD) score was 13.0 +/- 6.0, and the proportion with Child-Turcotte-Pugh (CTP) A/B/C was 51%/31%/12%, respectively. Mean HCV RNA at DCV initiation was 14.3x6 log(10) IU/mL, and 37% had severe cholestatic HCV infection. Antiviral regimens were selected by the local investigator and included DCV+SOF (n=77), DCV+SMV (n=18), and DCV+SMV+SOF (n=2); 35% overall received RBV. At the end of treatment (EOT) and 12 weeks after EOT, 88 (91%) and 84 (87%) patients, respectively, were HCV RNA negative or had levels <43 IU/mL. CTP and MELD scores significantly improved between DCV-based treatment initiation and last contact. Three virological breakthroughs and 2 relapses occurred in patients treated with DCV+SMV with or without RBV. None of the 8 patient deaths (6 during and 2 after therapy) were attributed to therapy. In conclusion, DCV-based all-oral antiviral therapy was well tolerated and resulted in a high sustained virological response in LT recipients with severe recurrent HCV infection. Most treated patients experienced stabilization or improvement in their clinical status. 

  • 94.
    Forsell, Joakim
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Genetic subtypes in unicellular intestinal parasites with special focus on Blastocystis2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The development of molecular tools for detection and typing of unicellular intestinal parasites has revealed genetic diversities in species that were previously considered as distinct entities. Of great importance is the genetic distinction found between the pathogenic Entamoeba histolytica and the non-pathogenic Entamoeba dispar, two morphologically indistinguishable species. Blastocystis sp. is a ubiquitous intestinal parasite with unsettled pathogenicity. Molecular studies of Blastocystis sp. have identified 17 genetic subtypes, named ST1-17. Genetically, these subtypes could be considered as different species, but it is largely unknown what phenotypic or pathogenic differences exist between them. This thesis explores molecular methods for detection and genetic subtyping of unicellular intestinal parasites, with special focus on Blastocystis.

    We found that PCR-based methods were highly sensitive for detection of unicellular intestinal parasites, but could be partially or completely inhibited by substances present in faeces. A sample transport medium containing guanidinium thiocyanate was shown to limit the occurrence of PCR inhibition.

    The prevalence of Blastocystis in Swedish university students was over 40%, which is markedly higher than what was previously estimated. Blastocystis ST3 and ST4 were the two most commonly found Blastocystis subtypes in Sweden, which is similar to results from other European countries.

    Blastocystis sp. and Giardia intestinalis were both commonly detected in Zanzibar, Tanzania, each with a prevalence exceeding 50%. Blastocystis ST1, ST2, and ST3 were common, but ST4 was absent. While G. intestinalis was most common in the ages 2-5 years, the prevalence of Blastocystis increased with increasing age, at least up to young adulthood. We found no statistical association between diarrhoea and Blastocystis sp., specific Blastocystis subtype or G. intestinalis.

    Metagenomic sequencing of faecal samples from Swedes revealed that Blastocystis was associated with high intestinal bacterial genus richness, possibly signifying gastrointestinal health. Blastocystis was also positively associated with the bacterial genera Sporolactobacillus and Candidatus Carsonella, and negatively associated with the genus Bacteroides.

    Blastocystis ST4 was shown to have limited intra-subtype genetic diversity and limited geographic spread. ST4 was also found to be the major driver behind the positive association between Blastocystis and bacterial genus richness and the negative association with Bacteroides.

  • 95.
    Forsell, Joakim
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Bengtsson-Palme, Johan
    Department of Infectious Diseases, Institute of Biomedicine, The Sahlgrenska Academy, and Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden.
    Angelin, Martin
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Johansson, Anders
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology. Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Evengård, Birgitta
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Granlund, Margareta
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    The relation between Blastocystis and the intestinal microbiota in Swedish travellers2017In: BMC Microbiology, ISSN 1471-2180, E-ISSN 1471-2180, Vol. 17, article id 231Article in journal (Refereed)
    Abstract [en]

    Background: Blastocystis sp. is a unicellular eukaryote that is commonly found in the human intestine. Its ability to cause disease is debated and a subject for ongoing research. In this study, faecal samples from 35 Swedish university students were examined through shotgun metagenomics before and after travel to the Indian peninsula or Central Africa. We aimed at assessing the impact of travel on Blastocystis carriage and seek associations between Blastocystis and the bacterial microbiota.

    Results: We found a prevalence of Blastocystis of 16/35 (46%) before travel and 15/35 (43%) after travel. The two most commonly Blastocystis subtypes (STs) found were ST3 and ST4, accounting for 20 of the 31 samples positive for Blastocystis. No mixed subtype carriage was detected. All ten individuals with a typable ST before and after travel maintained their initial ST. The composition of the gut bacterial community was not significantly different between Blastocystis-carriers and non-carriers. Interestingly, the presence of Blastocystis was accompanied with higher abundances of the bacterial genera Sporolactobacillus and Candidatus Carsonella. Blastocystis carriage was positively associated with high bacterial genus richness, and negatively correlated to the Bacteroides-driven enterotype. These associations were both largely dependent on ST4 – a subtype commonly described from Europe – while the globally prevalent ST3 did not show such significant relationships.

    Conclusions: The high rate of Blastocystis subtype persistence found during travel indicates that long-term carriage of Blastocystis is common. The associations between Blastocystis and the bacterial microbiota found in this study could imply a link between Blastocystis and a healthy microbiota as well as with diets high in vegetables. Whether the associations between Blastocystis and the microbiota are resulting from the presence of Blastocystis, or are a prerequisite for colonization with Blastocystis, are interesting questions for further studies.

  • 96.
    Furberg, Maria
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Anticona Huaynate, Cynthia
    Umeå University, Faculty of Medicine, Department of Epidemiology and Global Health.
    Schumann, Barbara
    Umeå University, Faculty of Medicine, Department of Epidemiology and Global Health.
    Post-infectious fatigue following Puumala virus infection2019In: Infectious Diseases, ISSN 2374-4235, E-ISSN 2374-4243, p. 1-8Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Puumala virus infection or nephropathia epidemica (NE) is common in northern Sweden. NE causes haemorrhagic fever with renal syndrome. Most patients make a full recovery, but a convalescent phase with fatigue has been reported. Although post-infectious fatigue has been demonstrated for other viral infections, it is not well studied in relation to NE. This study assessed recovery time and levels of fatigue in former NE patients, as compared to the general population.

    METHODS: NE patients diagnosed in northern Sweden between 2007 and 2011, together with a comparison sample from the general population, answered a questionnaire on demographic and health-related factors, including the Fatigue Severity Scale (FSS), and characteristics of NE infection. Self-reported recovery time was assessed, and fatigue levels were compared across the two groups by multiple linear regression, stratified by gender.

    RESULTS: In total, 1132 NE patients and 915 comparison group subjects participated. Time to complete recovery was reported to exceed 3 months for 47% and 6 months for 32% of the NE patients. Recovery time differed by gender and age. NE patients had significantly higher FSS scores than the comparison group. Differences were greater among women than men, and adjustments for current illness, body mass index, smoking and current residence only slightly modified the estimates.

    CONCLUSIONS: Individuals with previous NE infection show higher fatigue scores than non-infected individuals, even 5 years following the infection. Full recovery takes half a year or longer for a substantial proportion of former NE patients.

  • 97.
    Furberg, Maria
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Xijia, Liu
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Nystedt, Anders
    Stenmark, Stephan
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Elisasson, Mats
    Sellin, Mats
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Johansson, Andersson
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Tularemia in northern Sweden - sero-prevalence and a case-control study of risk factorsArticle in journal (Refereed)
  • 98. Gebieluca Dabul, Andrei Nicoli
    et al.
    Avaca-Crusca, Juliana Sposto
    Navais, Roberto Barranco
    São Carlos Institute of Physics, University of São Paulo, São Carlos, SP, Brazil.
    Merlo, Thaís Panhan
    Van Tyne, Daria
    Gilmore, Michael S.
    Baratella da Cunha Camargo, Ilana Lopes
    Molecular basis for the emergence of a new hospital endemic tigecycline-resistant Enterococcus faecalis ST103 lineage2019In: Infection, Genetics and Evolution, ISSN 1567-1348, E-ISSN 1567-7257, Vol. 67, p. 23-32Article in journal (Refereed)
    Abstract [en]

    Enterococcus faecalis are a major cause of nosocomial infection worldwide, and the spread of vancomycin resistant strains (VRE) limits treatment options. Tigecycline-resistant VRE began to be isolated from inpatients at a Brazilian hospital within months following the addition of tigecycline to the hospital formulary. This was found to be the result of a spread of an ST103 E. faecalis clone. Our objective was to identify the basis for tigecycline resistance in this lineage. The genomes of two closely related tigecycline-susceptible (MIC = 0.06 mg/L), and three representative tigecycline-resistant (MIC = 1 mg/L) ST103 isolates were sequenced and compared. Further, efforts were undertaken to recapitulate the emergence of resistant strains in vitro. The specific mutations identified in clinical isolates in several cases were within the same genes identified in laboratory-evolved strains. The contribution of various polymorphisms to the resistance phenotype was assessed by trans-complementation of the wild type or mutant alleles, by testing for differences in mRNA abundance, and/or by examining the phenotype of transposon insertion mutants. Among tigecycline-resistant clinical isolates, five genes contained non-synonymous mutations, including two genes known to be related to enterococcal tigecycline resistance (tetM and rpsJ). Finally, within the in vitro-selected resistant variants, mutation in the gene for a MarR-family response regulator was associated with tigecycline resistance. This study shows that E. faecalis mutates to attain tigecycline resistance through the complex interplay of multiple mechanisms, along multiple evolutionary trajectories.

  • 99. Gherasim, Alin
    et al.
    Hjertqvist, Marika
    Lundkvist, Åke
    Kühlmann-Berenzon, Sharon
    Verner Carlson, Jenny
    Stenmark, Stephan
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Widerström, Mikael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology. Department of Communicable Disease Control and Prevention, Jämtland County Council, Östersund, Sweden.
    Österlund, Anders
    Boman, Hans
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Wallensten, Anders
    Risk factors and potential preventive measures for nephropatia epidemica in Sweden 2011-2012: a case-control study2015In: Infection Ecology & Epidemiology, ISSN 2000-8686, E-ISSN 2000-8686, Vol. 5, article id 27698Article in journal (Refereed)
    Abstract [en]

    INTRODUCTION: Nephropatia epidemica (NE), a relatively mild form of hemorrhagic fever with renal syndrome caused by the Puumala virus (PUUV), is endemic in northern Sweden. We aim to study the risk factors associated with NE in this region.

    METHODS: We conducted a matched case-control study between June 2011 and July 2012. We compared confirmed NE cases with randomly selected controls, matched by age, sex, and place of infection or residence. We analyzed the association between NE and several occupational, environmental, and behavioral exposures using conditional logistic regression.

    RESULTS: We included in the final analysis 114 cases and 300 controls, forming 246 case-control pairs. Living in a house with an open space beneath, making house repairs, living less than 50 m from the forest, seeing rodents, and smoking were significantly associated with NE.

    CONCLUSION: Our results could orient public health policies targeting these risk factors and subsequently reduce the NE burden in the region.

  • 100. Gnann, John W, Jr
    et al.
    Sköldenberg, Birgit
    Hart, John
    Aurelius, Elisabeth
    Schliamser, Silvia
    Studahl, Marie
    Eriksson, Britt-Marie
    Hanley, Daniel
    Aoki, Fred
    Jackson, Alan C
    Griffiths, Paul
    Miedzinski, Lil
    Hanfelt-Goade, Diane
    Hinthorn, Daniel
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Aksamit, Allen
    Cruz-Flores, Salvador
    Dale, Ilet
    Cloud, Gretchen
    Jester, Penelope
    Whitley, Richard J
    Herpes Simplex Encephalitis: Lack of Clinical Benefit of Long-term Valacyclovir Therapy2015In: Clinical Infectious Diseases, ISSN 1058-4838, E-ISSN 1537-6591, Vol. 61, no 5, p. 683-691Article in journal (Refereed)
    Abstract [en]

    Background: Despite the proven efficacy of acyclovir (ACV) therapy, herpes simplex encephalitis (HSE) continues to cause substantial morbidity and mortality. Among patients with HSE treated with ACV, the mortality rate is approximately 14%-19%. Among survivors, 45%-60% have neuropsychological sequelae at 1 year. Thus, improving therapeutic approaches to HSE remains a high priority. Methods: Following completion of a standard course of intravenous ACV, 87 adult patients with HSE (confirmed by positive polymerase chain reaction [PCR] for herpes simplex virus DNA in cerebrospinal fluid) were randomized to receive either valacyclovir (VACV) 2 g thrice daily (n = 40) or placebo tablets (n = 47) for 90 days (12 tablets of study medication daily). The primary endpoint was survival with no or mild neuropsychological impairment at 12 months, as measured by the Mattis Dementia Rating Scale (MDRS). Logistic regression was utilized to assess factors related to the primary endpoint. Results: The demographic characteristics of the 2 randomization groups were statistically similar with no significant differences in age, sex, or race. At 12 months, there was no significant difference in the MDRS scoring for VACV-treated vs placebo recipients, with 85.7% and 90.2%, respectively, of patients demonstrating no or mild neuropsychological impairment (P = .72). No significant study-related adverse events were encountered in either treatment group. Conclusions: Following standard treatment with intravenous ACV for PCR-confirmed HSE, an additional 3-month course of oral VACV therapy did not provide added benefit as measured by neuropsychological testing 12 months later in a population of relatively high-functioning survivors.

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