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  • 1.
    Forsell, Joakim
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Granlund, Margareta
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Samuelsson, Linn
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Koskiniemi, Satu
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Edebro, Helen
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Evengård, Birgitta
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    High occurrence of Blastocystis sp subtypes 1-3 and Giardia intestinalis assemblage B among patients in Zanzibar, Tanzania2016In: Parasites & Vectors, ISSN 1756-3305, E-ISSN 1756-3305, Vol. 9, article id 370Article in journal (Refereed)
    Abstract [en]

    Background: Blastocystis is a common intestinal parasite with worldwide distribution but the distribution of Blastocystis and its subtypes in East Africa is largely unknown. In this study, we investigate the distribution of Blastocystis subtypes in Zanzibar, Tanzania and report the prevalence of intestinal parasites using both molecular methods and microscopy.

    Methods: Stool samples were collected from both diarrhoeic and non-diarrhoeic outpatients in Zanzibar. In addition to microscopy, real-time PCR for Blastocystis, Entamoeba histolytica and E. dispar, Giardia intestinalis, Cryptosporidium spp., and Dientamoeba fragilis was used. Blastocystis subtypes were determined by a conventional PCR followed by partial sequencing of the SSU-rRNA gene. Genetic assemblages of Giardia were determined by PCR with assemblage specific primers.

    Results: Intestinal parasites were detected in 85 % of the 174 participants, with two or more parasites present in 56 %. Blastocystis sp. and Giardia intestinalis were the most common parasites, identified by PCR in 61 and 53 % of the stool samples respectively, but no correlation between carriage of Blastocystis and Giardia was found. The Blastocystis subtype distribution was ST1 34.0 %, ST2 26.4 %, ST3 25.5 %, ST7 0.9 %, and 13.2 % were positive only by qPCR (non-typable). The Giardia genetic assemblages identified were A 6.5 %, B 85 %, A + B 4.3 %, and non-typable 4.3 %. The detection rate with microscopy was substantially lower than with PCR, 20 % for Blastocystis and 13.8 % for Giardia. The prevalence of Blastocystis increased significantly with age while Giardia was most prevalent in children two to five years old. No correlation between diarrhoea and the identification of Giardia, Blastocystis, or their respective genetic subtypes could be shown and, as a possible indication of parasite load, the mean cycle threshold values in the qPCR for Giardia were equal in diarrhoeic and non-diarrhoeic patients.

    Conclusions: Carriage of intestinal parasites was very common in the studied population in Zanzibar. The most commonly detected parasites, Blastocystis and Giardia, had different age distributions, possibly indicating differences in transmission routes, immunity, and/or other host factors for these two species. In the Blastocystis subtype analysis ST1-3 were common, but ST4, a subtype quite common in Europe, was completely absent, corroborating the geographical differences in subtype distributions previously reported.

  • 2.
    Forsell, Joakim
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Koskiniemi, Satu
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Hedberg, Ida
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Edebro, Helen
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Evengård, Birgitta
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Granlund, Margareta
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Evaluation of factors affecting real-time PCR performance for diagnosis of Entamoeba histolytica and Entamoeba dispar in clinical stool samples2015In: Journal of Medical Microbiology, ISSN 0022-2615, E-ISSN 1473-5644, Vol. 64, p. 1053-1062Article in journal (Refereed)
    Abstract [en]

    Although PCR offers the potential for sensitive detection of parasites:there are several pitfalls for optimal performance, especially when DNA is extracted from a complex sample material such as stool. With the aid of a sensitive inhibitor control in a duplex real-time PCR (qPCR) for identification of Entamoeba histolytica and Entamoeba dispar we have evaluated factors that influenced the performance of the qPCR and have suggested a rationale to be used in the analysis of clinical samples. Pre-PCR processing was found to be of outmost importance for an optimal amplification since inhibitors caused false-negative results when higher amounts of sample were used. Stool sampling with a flocked swab (ESwab, Copan), yielding on average 173 mg, gave positive qPCR results in samples with cysts of E. dispar that were negative in serially diluted stool samples. The degree of inhibition found varied between samples and was not an on-off phenomenon. Even low-grade inhibition, shown as an increase of two cycles in the qPCR for the inhibitor control, could lead to false negativity in samples with low amounts of parasites. Lack of amplification in the qPCR due to inhibition could be overcome by dilution of the extracted DNA by 1/10-1/20. We also describe the use of guanidinium thiocyanate buffer for transport and storage of samples as well as a time-saving semi-automated DNA extraction method in an Arrow instrument (Nordiag) preceded by bead beating.

  • 3.
    Lai, Xin-He
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Wang, S-Y
    Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology).
    Edebro, Helene
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Sjöstedt, Anders
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Francisella strains express hemolysins of distinct characteristics2003In: FEMS Microbiology Letters, ISSN 0378-1097, E-ISSN 1574-6968, Vol. 224, no 1, p. 91-95Article in journal (Refereed)
    Abstract [en]

    Historically, Francisella strains have been described as nonhemolytic. In this study, we show by use of solid and liquid hemolysis assays that some Francisella strains have hemolytic properties. The Francisella novicida type strain U112 is hemolytic to horse erythrocytes and Francisella philomiragia type strain FSC144 is hemolytic towards both human and horse erythrocytes. The F. novicida strain U112 released a protein (novilysin A) into the culture supernatant which cross-reacted with antiserum against Escherichia coli HlyA whereas there was no similar protein detectable with this cross-reactive property from the supernatant of the F. philomiragia strain.

  • 4. Saffari, Fereshteh
    et al.
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Gurram, Bharat Kumar
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Edebro, Helen
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Hojabri, Zoya
    Monsen, Tor
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Molecular and Phenotypic Characterization of Multidrug-Resistant Clones of Staphylococcus epidermidis in Iranian Hospitals: Clonal Relatedness to Healthcare-Associated Methicillin-Resistant Isolates in Northern Europe2016In: Microbial Drug Resistance, ISSN 1076-6294, E-ISSN 1931-8448, Vol. 22, no 7, p. 570-577Article in journal (Refereed)
    Abstract [en]

    The aim of the study was to investigate the molecular epidemiology of Staphylococcus epidermidis in Iranian hospitals and to compare the genotypes with a previously characterized collection of >1,300 S. epidermidis isolates of nosocomial and community origin from Northern Europe, Australia, and USA. In total, 82 clinical S. epidermidis isolates from three Iranian hospitals were examined by multilocus sequence typing, pulsed-field gel electrophoresis (PFGE) and staphylococcal cassette chromosome mec (SCCmec) typing. In addition, antimicrobial susceptibility, the presence of the ica operon, and the predilection to biofilm formation were assessed. Three predominant PFGE clones were found. The PFGE patterns of the most common sequence type (PFGE type 040-ST2) showed 80% similarity to multidrug-resistant S. epidermidis (MDRSE) clinical isolates from eight hospitals in Northern Europe. The second most common (PFGE 024-ST22) showed an unique PFGE pattern, whereas the third most predominant genotype (PFGE 011-ST5) proved indistinguishable to the PFGE Co-ST5 identified in five hospitals in Northern Europe. In conclusion, the study documented the dissemination of three MDRSE clones within and between hospitals in Iran and revealed an intercontinental spread of two clonal multidrug-resistant lineages (ST2 and ST5) in the hospital environment. Isolates of the predominant clones were significantly more frequently associated with multidrug-resistance and biofilm formation compared to nonclonal isolates. Further studies are needed to explore and characterize the genetic traits that enable these successful MDRSE clones to persist and disseminate worldwide in the healthcare settings.

  • 5.
    Widerström, Micael
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology. Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Monsen, Tor
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Karlsson, Carina
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Edebro, Helén
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Johansson, Anders
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases. Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Wiström, Johan
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Clonality among multidrug-resistant hospital-associated Staphylococcus epidermidis in northern Europe2009In: Scandinavian Journal of Infectious Diseases, ISSN 0036-5548, E-ISSN 1651-1980, Vol. 41, no 9, p. 642-649Article in journal (Refereed)
    Abstract [en]

    Using pulsed-field gel electrophoresis (PFGE) we have previously described the occurrence and possible dissemination of a clone of multidrug-resistant Staphylococcus epidermidis (MDRSE) in 2 hospitals in northern Sweden during 2001-2003. The aims of the present study were to investigate if this clone still persisted, 7 y later, in these 2 hospitals and whether this specific clone was detectable among clinical isolates from 9 other hospitals, 6 Swedish as well as a Norwegian, Danish and a German hospital. In total, 173 clinical isolates of MDRSE isolated during 2003 to 2008 were analysed using PFGE, of which 22 isolates were also characterized by multilocus sequence typing (MLST). Two dominating PFGE types (types A and B) were identified, consisting of 56 (32%) and 38 (22%) isolates, respectively. Type A, which was detected in the Norwegian and all Swedish hospitals, proved indistinguishable to the clone previously identified in 2001-2003 and corresponded with a novel sequence type (ST215). Type B was discovered in the German, Danish and in 7 Swedish hospitals and corresponded with ST2. In conclusion, we have demonstrated the occurrence, persistence and potential dissemination of 2 MDRSE genotypes, including a novel sequence type (ST215), within hospitals in northern Europe.

  • 6.
    Widerström, Micael
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Wiström, Johan
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Edebro, Helén
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Marklund, Elisabeth
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Backman, Mattias
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Lindqvist, Per
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    Monsen, Tor
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Colonization of patients, healthcare workers, and the environment with healthcare-associated Staphylococcus epidermidis genotypes in an intensive care unit: a prospective observational cohort study2016In: BMC Infectious Diseases, ISSN 1471-2334, E-ISSN 1471-2334, Vol. 16, article id 743Article in journal (Refereed)
    Abstract [en]

    Background: During the last decades, healthcare-associated genotypes of methicillin-resistant Staphylococcus epidermidis (HA-MRSE) have been established as important opportunistic pathogens. However, data on potential reservoirs on HA-MRSE is limited. The aim of the present study was to investigate the dynamics and to which extent HA-MRSE genotypes colonize patients, healthcare workers (HCWs) and the environment in an intensive care unit (ICU).

    Methods: Over 12 months in 2006-2007, swab samples were obtained from patients admitted directly from the community to the ICU and patients transferred from a referral hospital, as well as from HCWs, and the ICU environment. Patients were sampled every third day during hospitalization. Antibiotic susceptibility testing was performed according to EUCAST guidelines. Pulsed-field gel electrophoresis and multilocus sequence typing were used to determine the genetic relatedness of a subset of MRSE isolates.

    Results: We identified 620 MRSE isolates from 570 cultures obtained from 37 HCWs, 14 patients, and 14 environmental surfaces in the ICU. HA-MRSE genotypes were identified at admission in only one of the nine patients admitted directly from the community, of which the majority subsequently were colonized by HA-MRSE genotypes within 3 days during hospitalization. Almost all (89%) of HCWs were nasal carriers of HA-MRSE genotypes. Similarly, a significant proportion of patients transferred from the referral hospital and fomites in the ICU were widely colonized with HA-MRSE genotypes.

    Conclusions: Patients transferred from a referral hospital, HCWs, and the hospital environment serve as important reservoirs for HA-MRSE. These observations highlight the need for implementation of effective infection prevention and control measures aiming at reducing HA-MRSE transmission in the healthcare setting.

  • 7.
    Widerström, Micael
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Wiström, Johan
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Ek, Elin
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Edebro, Helen
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Monsen, Tor
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Near absence of methicillin-resistance and pronounced genetic diversity among Staphylococcus epidermidis isolated from healthy persons in northern Sweden2011In: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS), ISSN 0903-4641, E-ISSN 1600-0463, Vol. 119, no 8, p. 505-512Article in journal (Refereed)
    Abstract [en]

    The main aim of the study was to examine if hospital-associated clones of multidrug-resistant Staphylococcus epidermidis (MDRSE), commonly identified in hospitals in our region, also are spread among healthy persons in the community. A total of 124 isolates of S. epidermidis sampled from subjects attending a Travel health clinic, Umeå, Sweden during 2008 were examined with antibiotic susceptibility testing and pulsed field gel electrophoresis (PFGE) analysis.

    Resistance to methicillin or any antibiotic was detected in two and 26 of the isolates, respectively. PFGE analysis showed an extensive genetic diversity with 86 different PFGE types, of whom 62 were singletons. No isolates belonged to the previously described hospital-associated MDRSE genotypes, indicating that MDRSE by large are confined to the hospital setting in our region. In conclusion, community-associated isolates of S. epidermidis showed a low level of methicillin-resistance and were genetically extremely diverse with no predominating genotype.

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