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  • 1. Adler, Sara
    et al.
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Lindh, Johan
    Lilja, Mikael
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine.
    Symptoms and risk factors of Cryptosporidium hominis infection in children: data from a large waterborne outbreak in Sweden2017In: Parasitology Research, ISSN 0932-0113, E-ISSN 1432-1955, Vol. 116, no 10, p. 2613-2618Article in journal (Refereed)
    Abstract [en]

    Cryptosporidium is a major cause of diarrheal disease worldwide. In developing countries, this infection is endemic and in children, associated with growth faltering and cognitive function deficits, with the most severe impact on those aged <2 years. Little has been reported about symptoms and risk factors for children in industrialized countries, although the disease incidence is increasing in such regions. In November 2010, a large waterborne outbreak of C. hominis occurred in the city of Östersund in Sweden. Approximately 27,000 of the 60,000 inhabitants were symptomatic. We aimed to describe duration of symptoms and the risk factors for infection with C. hominis in children aged <15 years in a Western setting. Within 2 months after a boil water advisory, a questionnaire was sent to randomly selected inhabitants of all ages, including 753 children aged <15 years. Those with ≥3 loose stools/day were defined as cases of diarrhoea. The response rate was 70.3%, and 211 children (39.9%) fulfilled the case definition. Mean duration of diarrhoea was 7.5 days (median 6, range 1-80 days). Recurrence, defined as a new episode of diarrhoea after ≥2 days of normal stools, occurred in 52.5% of the cases. Significant risk factors for infection, besides living within the distribution area of the contaminated water plant, included a high level of water consumption, male sex, and a previous history of loose stools. The outbreak was characterized by high attack and recurrence rates, emphasizing the necessity of water surveillance to prevent future outbreaks.

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  • 2.
    Andersson Norlén, Elina
    et al.
    Department of Infectious Diseases, Östersund Hospital, Östersund, Sweden.
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Lindam, Anna
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Olsson, Johanna
    Department of Microbiology, Östersund Hospital, Östersund, Sweden.
    Ryding, Ulf
    Department of Infectious Diseases, Östersund Hospital, Östersund, Sweden.
    Blood cultures with one venipuncture instead of two: a prospective clinical comparative single-center study including patients in the ICU, haematology, and infectious diseases departments2023In: Infectious Diseases, ISSN 2374-4235, E-ISSN 2374-4243, Vol. 55, no 9, p. 591-598Article in journal (Refereed)
    Abstract [en]

    Objectives: Blood culture is a key method for diagnosing bloodstream infections. In this prospective study, we aimed to investigate whether blood cultures collected with the one-puncture method results in fewer contaminants, i.e. microorganisms from the skin or the environment, and the same detection of relevant pathogens compared to the two-puncture method. Further, we aimed to investigate if the time to blood culture positivity could be useful in evaluating contaminants.

    Methods: Patients planned for blood cultures were asked to participate in the study. From each recruited patient, six blood culture bottles were drawn, bottles 1–4 from the first venipuncture and bottles 5–6 from the second venipuncture. Within each patient, bottles 1–4 were compared to bottles 1, 2, 5, and 6 for contaminants and relevant pathogens. A sub-analysis was conducted on patients admitted to the ICU and those in the haematology department. We also assessed time-to-positivity for coagulase-negative staphylococci.

    Results: In the final analysis, 337 episodes from 312 patients were included. Relevant pathogens were identified in 62/337 (18.4%) episodes in both methods. Contaminants were detected in 12 (3.6%) and 19 episodes (5.6%) using the one-puncture and two-puncture method (p =.039), respectively. Corresponding results were observed in the sub-analysis. Notably, relevant coagulase-negative staphylococci demonstrated a shorter time-to-positivity compared to contaminant coagulase-negative staphylococci.

    Conclusion: Blood cultures obtained using the one-puncture method resulted in significantly fewer contaminants and detected relevant pathogens equally to the two-puncture method. Time-to-positivity may be a useful additive indicator for predicting coagulase-negative staphylococci contamination in blood cultures.

  • 3.
    Andersson, T
    et al.
    Department of Mathematics, Stockholm University, Sweden and Swedish Institute for National Food Agency (SLV), Sweden and Communicable Disease Control (SMI), Solna, Sweden.
    Bjelkmar, P
    Swedish Institute for Communicable Disease Control (SMI), Solna, Sweden, and Inera AB, Sweden.
    Hulth, A
    Swedish Institute for Communicable Disease Control (SMI), Solna, Sweden.
    Lindh, J
    Department of Microbiology, Tumour and Cell Biology, Karolinska Institutet, Sweden and Swedish Institute for Communicable Disease Control (SMI), Solna, Sweden.
    Stenmark, Stephan
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases. County Medical Officer, Västerbotten, Sweden.
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology. Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Syndromic surveillance for local outbreak detection and awareness: evaluating outbreak signals of acute gastroenteritis in telephone triage, web-based queries and over-the-counter pharmacy sales2014In: Epidemiology and Infection, ISSN 0950-2688, E-ISSN 1469-4409, Vol. 142, no 2, p. 303-313Article in journal (Refereed)
    Abstract [en]

    For the purpose of developing a national system for outbreak surveillance, local outbreak signals were compared in three sources of syndromic data - telephone triage of acute gastroenteritis, web queries about symptoms of gastrointestinal illness, and over-the-counter (OTC) pharmacy sales of antidiarrhoeal medication. The data sources were compared against nine known waterborne and foodborne outbreaks in Sweden in 2007-2011. Outbreak signals were identified for the four largest outbreaks in the telephone triage data and the two largest outbreaks in the data on OTC sales of antidiarrhoeal medication. No signals could be identified in the data on web queries. The signal magnitude for the fourth largest outbreak indicated a tenfold larger outbreak than officially reported, supporting the use of telephone triage data for situational awareness. For the two largest outbreaks, telephone triage data on adult diarrhoea provided outbreak signals at an early stage, weeks and months in advance, respectively, potentially serving the purpose of early event detection. In conclusion, telephone triage data provided the most promising source for surveillance of point-source outbreaks.

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  • 4.
    Blom, Kim
    et al.
    Public Health Agency of Sweden, Sweden.
    Fjällström, Peter
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Molnár, Christian
    Department of Neurobiology, Care Sciences and Society, Karolinska Institutet and Familjeläkarna AB, Stockholm, Sweden.
    Åberg, Mikael
    Department of Medical Sciences, Clinical Chemistry and SciLifeLab Affinity Proteomics, Uppsala University, Uppsala, Sweden.
    Vikström, Linnea
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Wigren, Julia
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Bennet, Louise
    Clinical Studies Sweden, Forum South, Skåne University Hospital and Department of Clinical Sciences, Lund University, Lund, Sweden.
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Rasmussen, Gunlög
    School of Medical Sciences, Örebro University, Örebro, Sweden.
    Klingström, Jonas
    Department of Biomedical Clinical Sciences, Linköping University, Linköping, Sweden.
    Forsell, Mattias N. E.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Johansson, Anders
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    SARS-CoV-2-related mortality decrease in nursing home residents given multiple COVID-19 boosters2023In: The Lancet - Infectious diseases, ISSN 1473-3099, E-ISSN 1474-4457, Vol. 23, no 10, p. e393-e394Article in journal (Other academic)
  • 5.
    Boks, Marije
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine.
    Lilja, Mikael
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine.
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Karling, Pontus
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine.
    Lindam, Anna
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine.
    Eriksson, Axel
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Sjöström, Malin
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine.
    Increased incidence of late-onset inflammatory bowel disease and microscopic colitis after a Cryptosporidium hominis outbreak2022In: Scandinavian Journal of Gastroenterology, ISSN 0036-5521, E-ISSN 1502-7708, Vol. 57, no 12, p. 1443-1449Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: In 2010, 27,000 inhabitants (45% of the population) of Östersund, Sweden, contracted clinical cryptosporidiosis after drinking water contaminated with Cryptosporidium hominis. After the outbreak, local physicians perceived that the incidence of inflammatory bowel disease (IBD), including ulcerative colitis (UC), Crohn's disease (CD), and IBD-unclassified, and microscopic colitis (MC) increased. This study assessed whether this perception was correct.

    MATERIALS AND METHODS: This observational study included adult patients (≥18 years old) from the local health care region who were diagnosed with pathology-confirmed IBD or MC during 2006-2019. We collected and validated the diagnosis, date of diagnosis, age at diagnosis, and sex from the Swedish quality register SWIBREG and electronic patient records. Population data were collected from Statistics Sweden. The incidences for 2006-2010 (pre-outbreak) and 2011-2019 (post-outbreak) were evaluated by negative binomial regression analysis and presented as incidence rate ratios (IRRs). Data were analyzed for IBD, for UC and CD separately, and MC.

    RESULTS: During the study period, we identified 410 patients with new onset IBD and 155 new cases of MC. Overall, we found a trend toward an increased incidence of IBD post-outbreak (IRR 1.39, confidence interval (CI) 0.99-1.94). In individuals ≥40 years old, the post-outbreak incidence significantly increased for IBD (IRR 1.69, CI 1.13-2.51) and CD (IRR 2.23, CI 1.08-4.62). Post-outbreak incidence of MC increased 6-fold in all age groups (IRR 6.43, CI 2.78-14.87).

    CONCLUSIONS: The incidence of late-onset IBD and MC increased after the Cryptosporidium outbreak. Cryptosporidiosis may be an environmental risk factor for IBD and MC.

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  • 6.
    Boks, Marije
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Lilja, Mikael
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Karling, Pontus
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Lindam, Anna
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Sjöström, Malin
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Persisting symptoms after Cryptosporidium hominis outbreak: a 10-year follow-up from Östersund, Sweden2023In: Parasitology Research, ISSN 0932-0113, E-ISSN 1432-1955, Vol. 122, no 7, p. 1631-1639Article in journal (Refereed)
    Abstract [en]

    In late 2010, an outbreak of Cryptosporidium hominis affected 27,000 inhabitants (45%) of Östersund, Sweden. Previous research shows that abdomen and joint symptoms commonly persist up to 5 years post-infection. It is unknown whether Cryptosporidium is associated with sequelae for a longer duration, how persisting symptoms present over time, and whether sequelae are associated with prolonged infection. In this prospective cohort study, a randomly selected cohort in Östersund was surveyed about cryptosporidiosis symptoms in 2011 (response rate 69.2%). A case was defined as a respondent reporting new diarrhoea episodes during the outbreak. Follow-up questionnaires were sent after 5 and 10 years. Logistic regressions were used to examine associations between case status and symptoms reported after 10 years, with results presented as adjusted odds ratios (aOR) with 95% confidence intervals. Consistency of symptoms and associations with case status and number of days with symptoms during outbreak were analysed using X 2 and Mann–Whitney U tests. The response rate after 10 years was 74% (n = 538). Case status was associated with reporting symptoms, with aOR of ~3 for abdominal symptoms and ~2 for joint symptoms. Cases were more likely to report consistent symptoms. Cases with consistent abdominal symptoms at follow-up reported 9.2 days with symptoms during the outbreak (SD 8.1), compared to 6.6 days (SD 6.1) for cases reporting varying or no symptoms (p = 0.003). We conclude that cryptosporidiosis was associated with an up to threefold risk for reporting symptoms 10 years post-infection. Consistent symptoms were associated with prolonged infection.

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  • 7.
    Fischerstrom, Karolina
    et al.
    Public Health Agency of Sweden (PHAS), Solna, Sweden; ECDC Fellowship Programme Field Epidemiology path (EPIET), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden.
    Dryselius, Rikard
    Public Health Agency of Sweden (PHAS), Solna, Sweden.
    Lindblad, Mats
    Swedish Food Agency (SFA), Uppsala, Sweden.
    Kuhlmann-Berenzon, Sharon
    Public Health Agency of Sweden (PHAS), Solna, Sweden.
    Karamehmedovic, Nadja
    Public Health Agency of Sweden (PHAS), Solna, Sweden.
    Borjesson, Stefan
    Public Health Agency of Sweden (PHAS), Solna, Sweden; School of Health Science, Örebro University, Örebro, Sweden.
    Hashemi, Nasanin
    Public Health Agency of Sweden (PHAS), Solna, Sweden.
    Gunn, Ingrid
    Department of Infectious Disease Prevention and Control, Region Kalmar County, Kalmar, Sweden.
    Gustavsson, Ann-Mari
    Department of Infection Prevention and Control, County of Värmland, Karlstad, Sweden.
    Lindroos, Nilla
    Department of Infectious Disease Prevention and Control, Region Halland, Halmstad, Sweden.
    Nederby-Ohd, Joanna
    Department of Infectious Disease Prevention and Control, Stockholm Region, Stockholm, Sweden.
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Rimhanen-Finne, Ruska
    Department of Health Security, Finnish Institute for Health and Welfare, Helsinki, Finland.
    Vainio, Anni
    Department of Health Security, Finnish Institute for Health and Welfare, Helsinki, Finland.
    Rehn, Moa
    Public Health Agency of Sweden (PHAS), Solna, Sweden.
    Outbreak of salmonella typhimurium linked to swedish pre-washed rocket salad, Sweden, September to November 20222024In: Eurosurveillance, ISSN 1025-496X, E-ISSN 1560-7917, Vol. 29, no 10, article id 2300299Article in journal (Refereed)
    Abstract [en]

    In September 2022, the Public Health Agency of Sweden observed an increase in domestic Salmonella Typhimurium cases through the Swedish electronic notification system, and an outbreak strain was identified with whole genome sequencing. Overall, 109 cases with symptom onset between 17 September and 24 November 2022 were reported from 20 of 21 Swedish regions. The median age of cases was 52 years (range 4-87 years) and 62% were female. A case-control study found cases to be associated with consumption of rocket salad (adjusted odds ratio (aOR) = 4.9; 95% confidence interval (CI): 2.4-10, p value < 0.001) and bagged mixed salad (aOR = 4.0; 95% CI: 1.9-8.1, p value < 0.001). Traceback, supported by Finnish authorities who identified the Swedish outbreak strain in a Finnish cluster during the same time period, identified rocket salad, cultivated, pre-washed and pre-packed in Sweden as the likely source of the outbreak. No microbiological analyses of rocket salad were performed. Our investigation indicates that bagged leafy greens such as rocket salad, regardless of pre-washing procedures in the production chain, may contain Salmonella and cause outbreaks, posing a health risk to consumers. We emphasise the need for primary producers of leafy greens to identify possible contamination points to prevent outbreaks.

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  • 8. 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, 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.

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  • 9.
    Gibbs, Anna
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Maripuu, Martin
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Öhlund, Louise
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Nilsson, Niklas Harry
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Werneke, Ursula
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry. Department of Psychiatry, Sunderby Hospital, Luleå, Sweden.
    COVID-19-associated mortality in individuals with serious mental disorders in Sweden during the first two years of the pandemic: a population-based register study2024In: BMC Psychiatry, E-ISSN 1471-244X, Vol. 24, no 1, article id 189Article in journal (Refereed)
    Abstract [en]

    Background: Reports at the beginning of the COVID-19 pandemic suggested differences in COVID-19-associated mortality between individuals with serious mental disorders (SMD) and the population at large.

    Aim: To compare the pattern of COVID-19-associated mortality in individuals with and without SMD in Sweden over the two main pandemic years.

    Methods: We compared the pattern of COVID-19-associated mortality in individuals with and without SMD in Sweden during 2020 and 2021. For SMD, we included psychotic disorder, bipolar disorder, and severe depression. The analysis was based on summary data from the Swedish Board of Health and Welfare covering the entire adult Swedish population.

    Results: The overall relative risk (RR) for experiencing a COVID-19-associated death was 1.66 (CI 1.50–1.83; p < 0.001) for individuals with SMD versus individuals without SMD. The corresponding RRs were 3.25 (CI 2.84–3.71; p < 0.001) for individuals with psychotic disorder, 1.06 (CI 0.88–1.26; p = 0.54) for individuals with bipolar disorder, and 1.03 (CI 0.80–1.32; p = 0.80) for individuals with severe depression. Compared to their respective counterparts in the non-SMD group, in the psychotic disorder and severe depression group, the RR were higher in women than in men. In the bipolar disorder group, the RR was higher in men than in women. The RR of COVID-19-associated death was generally higher in younger individuals with SMD. Individuals with psychosis between 18 and 59 years had the highest RR of COVID-19-associated death with 7.25 (CI 4.54–11.59; p<0.001).

    Conclusions: Individuals with SMD, and particularly those with psychotic disorders, had a higher risk of COVID-19-associated death than the general population. As this is a pattern also seen with other infections, people with SMD may be similarly vulnerable in future pandemics.

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  • 10. Hedin, G
    et al.
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology. Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Endocarditis due to Staphylococcus sciuri.1998In: European Journal of Clinical Microbiology and Infectious Diseases, ISSN 0934-9723, E-ISSN 1435-4373, Vol. 17, no 9, p. 673-5Article in journal (Refereed)
  • 11.
    Hedman, Elin
    et al.
    Infektionskliniken, Östersunds sjukhus, Östersund, Sverige.
    Fohlin, Lisa
    Infektionskliniken, Östersunds sjukhus, Östersund, Sverige.
    Hellmark, Bengt
    Laboratoriemedicin, Östersunds sjukhus, Östersund, Sverige.
    Aspevall, Olov
    Folkhälsomyndigheten, Stockholm, Sverige.
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Fem fall av C canimorsus på kort tid vid Östersunds sjukhus: [Five cases of C. canimorsus during a short period of time at Östersund Hospital, Sweden]2023In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 120, article id 22150Article in journal (Refereed)
    Abstract [en]

    We report a sudden increase in the number of cases of C. canimorsus bacteremia during 3 months in 2022 at Östersund Hospital, Sweden. Prior to these cases, the most recent one in the region occurred in 2015. Among the five cases, one suffered from meningitis and one was diagnosed as endocarditis. Dog contact was present in all cases, although dog bites could only be verified in two. Improved diagnostics could not be an explanation to the surge, since the analysis method for blood culture had been the same since 2015. No corresponding increase was noted nationally, according to the Public Health Agency of Sweden. The isolates have been included in the ongoing global study with the aim to explore Capnocytophaga in humans and animals using comparative genomics and genome wide association studies. The study is supported by several ESCMID (European Society of Clinical Microbiology and Infectious Diseases) study groups.

  • 12.
    Hulterström, Anna Karin
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, Dental Technology/Dental Materials Science.
    Sellin, Mats
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Monsen, Tor
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Gurram, Bharath Kumar
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Berggren, Diana
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Otorhinolaryngology.
    Bacterial flora and the epidemiology of staphylococcus aureus in the nose among patients with symptomatic nasal septal perforations2016In: Acta Oto-Laryngologica, ISSN 0001-6489, E-ISSN 1651-2251, Vol. 136, no 6, p. 620-625Article in journal (Refereed)
    Abstract [en]

    Conclusions Patients with symptomatic perforations of the nasal septum had a high prevalence of S. aureus in the nasal mucosa. Pulsed field gel electrophoresis (PFGE) analysis revealed a high genetic heterogeneity of S. aureus among both patients and controls. This indicates that presence of different strains of S. aureus can maintain a chronic inflammation in symptomatic nasal septal perforations. Objective The purpose of this study was to investigate the microbial flora around nasal septal perforations in patients having severe symptoms regarding bleeding, obstruction, and crustation associated with their perforation. Methods Twenty-five patients with untreated symptomatic nasal septal perforations were included. For culture, swabs around the perforations were collected. Bacteria were identified with standard laboratory techniques including a MALDI-TOF mass spectrometer. Epidemiological analysis was done using PFGE protocols. Bacteriological data were compared with data from a healthy control group. Results Staphylococcus aureus was present in the mucosa surrounding the nasal perforation significantly more often (p < 0.0001) in the patients (88%) compared to a control group (13%). Corynebacterium spp. and Propionibacterium spp. were significantly more frequently identified in the control group. The PFGE analysis of S. aureus strains revealed a high genetic heterogeneity and no specific S. aureus genotypes were associated with septal perforation.

  • 13.
    Johansson, Anders
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology. Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Lärkeryd, Adrian
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Mörtberg, Sara
    Myrtännäs, Kerstin
    Ohrman, Caroline
    Birdsell, Dawn
    Keim, Paul
    Wagner, David M
    Forsman, Mats
    Larsson, Pär
    An outbreak of respiratory tularemia caused by diverse clones of Francisella tularensis2014In: Clinical Infectious Diseases, ISSN 1058-4838, E-ISSN 1537-6591, Vol. 59, no 11, p. 1546-53Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: The bacterium Francisella tularensis is recognized for its virulence, infectivity, genetic homogeneity, and potential as a bioterrorism agent. Outbreaks of respiratory tularemia, caused by inhalation of this bacterium, are poorly understood. Such outbreaks are exceedingly rare, and F. tularensis is seldom recovered from clinical specimens.

    METHODS: A localized outbreak of tularemia in Sweden was investigated. Sixty-seven humans contracted laboratory-verified respiratory tularemia. F. tularensis subspecies holarctica was isolated from the blood or pleural fluid of 10 individuals from July to September 2010. Using whole-genome sequencing and analysis of single-nucleotide polymorphisms (SNPs), outbreak isolates were compared with 110 archived global isolates.

    RESULTS: There were 757 SNPs among the genomes of the 10 outbreak isolates and the 25 most closely related archival isolates (all from Sweden/Finland). Whole genomes of outbreak isolates were >99.9% similar at the nucleotide level and clustered into 3 distinct genetic clades. Unexpectedly, high-sequence similarity grouped some outbreak and archival isolates that originated from patients from different geographic regions and up to 10 years apart. Outbreak and archival genomes frequently differed by only 1-3 of 1 585 229 examined nucleotides.

    CONCLUSIONS: The outbreak was caused by diverse clones of F. tularensis that occurred concomitantly, were widespread, and apparently persisted in the environment. Multiple independent acquisitions of F. tularensis from the environment over a short time period suggest that natural outbreaks of respiratory tularemia are triggered by environmental cues. The findings additionally caution against interpreting genome sequence identity for this pathogen as proof of a direct epidemiological link.

  • 14.
    Kellgren, Therese
    et al.
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Dwibedi, Chinmay Kumar
    Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS). Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Monsen, Tor J.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Rydén, Patrik
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Johansson, Anders
    Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS). Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    The emergence of an antimicrobial resistant Staphylococcus epidermidis clone in Northern EuropeManuscript (preprint) (Other academic)
  • 15.
    Kellgren, Therese
    et al.
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Dwibedi, Chinmay Kumar
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology. Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Sundell, David
    Division of CBRN Defence and Security, Swedish Defense Research Agency, SE, Umeå, Sweden.
    Öhrman, Caroline
    Division of CBRN Defence and Security, Swedish Defense Research Agency, SE, Umeå, Sweden.
    Sjödin, Andreas
    Division of CBRN Defence and Security, Swedish Defense Research Agency, SE, Umeå, Sweden.
    Monsen, Tor J.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Rydén, Patrik
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Johansson, Anders
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology. Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Completed genome and emergence scenario of the multidrug-resistant nosocomial pathogen Staphylococcus epidermidis ST2152024In: BMC Microbiology, E-ISSN 1471-2180, Vol. 24, no 1, article id 215Article in journal (Refereed)
    Abstract [en]

    Background: A multidrug-resistant lineage of Staphylococcus epidermidis named ST215 is a common cause of prosthetic joint infections and other deep surgical site infections in Northern Europe, but is not present elsewhere. The increasing resistance among S. epidermidis strains is a global concern. We used whole-genome sequencing to characterize ST215 from healthcare settings.

    Results: We completed the genome of a ST215 isolate from a Swedish hospital using short and long reads, resulting in a circular 2,676,787 bp chromosome and a 2,326 bp plasmid. The new ST215 genome was placed in phylogenetic context using 1,361 finished public S. epidermidis reference genomes. We generated 10 additional short-read ST215 genomes and 11 short-read genomes of ST2, which is another common multidrug-resistant lineage at the same hospital. We studied recombination’s role in the evolution of ST2 and ST215, and found multiple recombination events averaging 30–50 kb. By comparing the results of antimicrobial susceptibility testing for 31 antimicrobial drugs with the genome content encoding antimicrobial resistance in the ST215 and ST2 isolates, we found highly similar resistance traits between the isolates, with 22 resistance genes being shared between all the ST215 and ST2 genomes. The ST215 genome contained 29 genes that were historically identified as virulence genes of S. epidermidis ST2. We established that in the nucleotide sequence stretches identified as recombination events, virulence genes were overrepresented in ST215, while antibiotic resistance genes were overrepresented in ST2.

    Conclusions: This study features the extensive antibiotic resistance and virulence gene content in ST215 genomes. ST215 and ST2 lineages have similarly evolved, acquiring resistance and virulence through genomic recombination. The results highlight the threat of new multidrug-resistant S. epidermidis lineages emerging in healthcare settings.

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  • 16.
    Lilja, Mikael
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine.
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Lindh, Johan
    Persisting post-infection symptoms 2 years after a large waterborne outbreak of Cryptosporidium hominis in northern Sweden2018In: BMC Research Notes, E-ISSN 1756-0500, Vol. 11, no 1, article id 625Article in journal (Refereed)
    Abstract [en]

    Objectives: In 2010–2011, a large waterborne outbreak of Cryptosporidium hominis affected the city of Östersund in Sweden. Previous findings had suggested that gastrointestinal symptoms can persist for up to 11 months after the initial infection. Here we investigated whether the parasite could cause sequelae in infected individuals up to 28 months after the outbreak. We compared cases linked to the outbreak and the previous follow-up study with non-cases regarding symptoms present up to 28 months after the initial infection. We investigated whether cases were more likely to report a list of symptoms at follow-up compared to non-cases, calculating odds ratio and 95% confidence interval obtained through logistic regression.

    Results: A total of 559 individuals (215 cases) were included in the study. Forty-eight percent of the outbreak cases reported symptoms at follow-up. Compared to non-cases, cases were more likely to report watery diarrhea, diarrhea, abdominal pain, fatigue, nausea, headache, or joint stiffness/pain/discomfort at follow-up after adjusting for age and sex. Our findings suggest that gastrointestinal symptoms and joint pain can persist several years after the initial Cryptosporidium infection and should be regarded as a potential cause of unexplained gastrointestinal symptoms or joint pain in people who have had this infection.

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  • 17.
    Maripuu, Martin
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Bendix, Marie
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry. Department of Clinical Neuroscience, Center for Psychiatry Research & Stockholm Health Care Services, Stockholm County Council, Karolinska Institutet, Stockholm, Sweden.
    Öhlund, Louise
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Werneke, Ursula
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Death Associated With Coronavirus (COVID-19) Infection in Individuals With Severe Mental Disorders in Sweden During the Early Months of the Outbreak: An Exploratory Cross-Sectional Analysis of a Population-Based Register Study2021In: Frontiers in Psychiatry, E-ISSN 1664-0640, Vol. 11, article id 609579Article in journal (Refereed)
    Abstract [en]

    Background: Individuals with severe mental disorder (SMD) have a higher risk of somatic comorbidity and mortality than the rest of the population. We set up a population-based study to assess whether individuals with SMD had a higher risk of death associated with a COVID-19 infection (COVID-19 associated death) than individuals without SMD.

    Methods: Exploratory analysis with a cross-sectional design in the framework of a population-based register study covering the entire Swedish population. The Swedish Board for Health and Welfare (Socialstyrelsen) provided anonymized tabulated summary data for further analysis. We compared numbers of COVID-19 associated death in individuals with SMD (cases) and without SMD (controls). We calculated the odds ratio (OR) for the whole sample and by age group and four comorbidities, namely diabetes, cardiovascular disease, hypertension, chronic lung disease.

    Results: The sample comprised of 7,923,859 individuals, 103,999 with SMD and 7,819,860 controls. There were 130 (0.1%) COVID-19 associated deaths in the SMD group and 4,945 (0.06%) in the control group, corresponding to an OR of 1.98 (CI 1.66-2.35; p < 0.001). The odds were 4-fold for the age groups between 60 and 79 years and 1.5-fold for cardiovascular diseases. Individuals with SMD without any of the risk factors under study had 3-fold odds of COVID-19 associated death.

    Conclusion: Our preliminary results identify individuals with SMD as a further group at increased risk of COVID-19 associated death. In regard to comorbidities, future studies should explore the potential confounding or mediation role in the relationship between SMD and COVID-19 associated deaths.

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  • 18.
    Monsen, Tor
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Lövgren, Elisabeth
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Wallinder, Lars
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    In vitro effect of ultrasound on bacteria and suggested protocol for sonication and diagnosis of prosthetic infections2009In: Journal of Clinical Microbiology, ISSN 0095-1137, E-ISSN 1098-660X, Vol. 47, no 8, p. 2496-2501Article in journal (Refereed)
    Abstract [en]

    Sonication of implants has been shown to be a promising method for diagnosis of prosthetic infections due to its improved sensitivity, simplicity, and low cost. The aim of the present study was to evaluate the effects of ultrasound performed under different conditions regarding temperature, duration, and composition of sonication tubes on bacterial species often associated with prosthetic infections. We found that ultrasound had an inhibitory effect on bacteria, of which gram-negative bacteria, in particular Escherichia coli, were almost eradicated after 5 min of sonication at 35 degrees C. Gram-positive bacteria were found to be resistant to the effect of ultrasound. Four factors were important for the inhibitory effect of sonication: the type of microorganism, the temperature of the sonication buffer, the duration of exposure to ultrasound (minutes), and the material and composition of the sonication tube in which sonication is performed. On the basis of the results from the present study, we propose a protocol for sonication and recovery of bacteria associated with biofilm on infected implants prior to conventional culture. From the present protocol, we recommend sonication for 7 min at 22 degrees C at the maximum effect which permits survival of gram-negative bacteria.

  • 19.
    Nilsson, Niklas Harry
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Bendix, Marie
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry. Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet & Stockholm Health Care Services, Region Stockholm, Sweden.
    Öhlund, Louise
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Werneke, Ursula
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Maripuu, Martin
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Increased Risks of Death and Hospitalization in Influenza/Pneumonia and Sepsis for Individuals Affected by Psychotic Disorders, Bipolar Disorders, and Single Manic Episodes: A Retrospective Cross-Sectional Study2021In: Journal of Clinical Medicine, E-ISSN 2077-0383, Vol. 10, no 19, article id 4411Article in journal (Refereed)
    Abstract [en]

     Individuals with severe mental disorders (SMDs) such as psychotic disorders, bipolar disorders, and single manic episodes have increased mortality associated with COVID-19 infection. We set up a population-based study to examine whether individuals with SMD also had a higher risk of hospitalization and death from other infectious conditions. Anonymized and summarized data from multiple Swedish patient registers covering the entire Swedish population were supplied by the Swedish National Board of Health and Welfare. The frequencies of hospitalizations and deaths associated with influenza/pneumonia and sepsis in individuals with SMD were compared with the rest of the population during 2018–2019. Possible contributing comorbidities were also examined, of which diabetes, cardiovascular disease, chronic lung disease, and hypertension were chosen. A total of 7,780,727 individuals were included in the study; 97,034 (1.2%) cases with SMD and 7,683,693 (98.8%) controls. Individuals with SMD had increased risk of death associated with influenza/pneumonia (OR = 2.06, 95% CI [1.87–2.27]) and sepsis (OR = 1.61, 95% CI [1.38–1.89]). They also had an increased risk of hospitalization associated with influenza/pneumonia (OR = 2.12, 95% CI [2.03–2.20]) and sepsis (OR = 1.89, 95% CI [1.75–2.03]). Our results identify a need for further evaluation of whether these individuals should be included in prioritized risk groups for vaccination against infectious diseases other than COVID-19.

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  • 20.
    Persson Waller, K.
    et al.
    Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute (SVA), Uppsala, Sweden.
    Myrenås, M.
    Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute (SVA), Uppsala, Sweden.
    Börjesson, S.
    School of Health Science, Örebro University, Örebro, Sweden.
    Kim, H.
    Department of Disease Control and Epidemiology, National Veterinary Institute (SVA), Uppsala, Sweden.
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Monsen, Tor J.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Sigurðarson Sandholt, A.K.
    deCODE genetics, Sturlugata 8, Reykjavik, Iceland.
    Östlund, E.
    Department of Microbiology, National Veterinary Institute (SVA), Uppsala, Sweden.
    Cha, W.
    Department of Disease Control and Epidemiology, National Veterinary Institute (SVA), Uppsala, Sweden.
    Genotypic characterization of Staphylococcus chromogenes and Staphylococcus simulans from Swedish cases of bovine subclinical mastitis2023In: Journal of Dairy Science, ISSN 0022-0302, E-ISSN 1525-3198, Vol. 106, no 11, p. 7991-8004Article in journal (Refereed)
    Abstract [en]

    Staphylococcus chromogenes and Staphylococcus simulans are commonly found in intramammary infections (IMI) associated with bovine subclinical mastitis, but little is known about genotypic variation and relatedness within species. This includes knowledge about genes encoding antimicrobial resistance (AMR) and potential virulence factors (pVF). The aim of this study was therefore to investigate these aspects by whole-genome sequencing of milk isolates from Swedish dairy cows with subclinical mastitis in an observational study. We also wanted to study if specific genotypes were associated with persistent IMI and the inflammatory response at udder quarter level. In total, 105 and 118 isolates of S. chromogenes and S. simulans, respectively, were included. Isolates were characterized using a 7-locus multilocus sequence typing (7-MLST), core genome analysis and in-silico analysis of AMR and pVF genes. Forty-seven sequence types (ST) and 7 core genome clusters of S. chromogenes were identified, and the most common ST were ST-6 and ST-109, both belonging to cluster VII. A 7-locus MLST scheme for S. simulans was not available, but 3 core genome clusters and 5 subclusters were described. Overall, substantial variation in ST and clusters among cows and herds were found in both species. Some ST of S. chromogenes were found in several herds, indicating spread between herds. Moreover, within-herd spread of the same genotype was observed for both species. Only a few AMR genes [blaZ, strpS194, vga(A)] were detected in a limited number of isolates, with the exception of blaZ coding for β-lactamase, which was identified in 22% of the isolates of S. chromogenes with ST-19, ST-102, and ST-103 more commonly carrying this gene compared with other ST. However, the blaZ gene was not identified in S. simulans. The average total number of pVF detected per isolate was similar in S. chromogenes (n = 30) and S. simulans (n = 33), but some variation in total numbers and presence of specific pVF or functional groups of pVF, was shown between ST/clusters within species. Differences in inflammatory response and potentially in persistent IMI at udder quarter level were found between S. chromogenes subtypes but not between S. simulans subtypes. In conclusion, the results from the present study generates new insight into the epidemiology of bovine S. chromogenes and S. simulans IMI, which can have implications for future prevention and antimicrobial treatment of infections related to these species.

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  • 21. Rehn, Moa
    et al.
    Wallensten, Anders
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Lilja, Mikael
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine.
    Grunewald, Maria
    Stenmark, Stephan
    Kark, Malin
    Lindh, Johan
    Post-infection symptoms following two large waterborne outbreaks of Cryptosporidium hominis in Northern Sweden, 2010-20112015In: BMC Public Health, E-ISSN 1471-2458, Vol. 15, article id 529Article in journal (Refereed)
    Abstract [en]

    Background: In 2010-2011, two large waterborne outbreaks caused by Cryptosporidium hominis affected two cities in Sweden, Ostersund and Skelleftea. We investigated potential post-infection health consequences in people who had reported symptoms compatible with cryptosporidiosis during the outbreaks using questionnaires. Methods: We compared cases linked to these outbreaks with non-cases in terms of symptoms present up to eleven months after the initial infection. We examined if cases were more likely to report a list of symptoms at follow-up than non-cases, calculating odds ratios (OR) and 95 % confidence intervals (CI) obtained through logistic regression. Results: A total of 872 (310 cases) and 743 (149 cases) individuals responded to the follow-up questionnaires in Ostersund and Skelleftea respectively. Outbreak cases were more likely to report diarrhea (Ostersund OR: 3.3, CI: 2.0-5.3. Skelleftea OR: 3.6, CI: 2.0-6.6), watery diarrhea (Ostersund OR: 3.4, CI: 1.9-6.3. Skelleftea OR: 2.8, CI: 1.5-5.1) abdominal pain (Ostersund OR: 2.1, CI: 1.4-3.3, Skelleftea OR: 2.7, CI: 1.5-4.6) and joint pain (Ostersund OR: 2.0, CI: 1.2-3.3, Skelleftea OR: 2.0, CI: 1.1-3.6) at follow-up compared to non-cases. Conclusions: Our findings suggest that gastrointestinal-and joint symptoms can persist several months after the initial infection with Cryptosporidium and should be regarded as a potential cause of unexplained symptoms in people who have suffered from the infection.

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  • 22. Ridderstedt, Frida
    et al.
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology. Unit of Communicable Disease Control and Prevention – Östersund.
    Lindh, Johan
    Lilja, Mikael
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine. Unit of Clinical Research Center – Östersund.
    Sick leave due to diarrhea caused by contamination of drinking water supply with Cryptosporidium hominis in Sweden: a retrospective study2018In: Journal of Water and Health, ISSN 1477-8920, E-ISSN 1996-7829, Vol. 16, no 5, p. 704-710Article in journal (Refereed)
    Abstract [en]

    We investigated sick leave from work, studies, preschool, and kindergarten occurring between 1 November 2010 and 31 January 2011 and associated with a waterborne outbreak of diarrhea caused by Cryptosporidium hominis in late November 2010 in Östersund, Sweden with 45.2% of 60,000 residents being symptomatic. A questionnaire defining acute watery diarrhoea and/or ≥3 diarrhea episodes/day as cryptosporidiosis was sent to 1,508 residents in late January 2011 (response rate 69.2%). Among adults aged 18–60 years, 24.0% took sick leave for a mean of 4.6 (SD ± 4.0) days due to cryptosporidiosis, and an additional 10.6% were absent from work a mean of 4.0 (±2.2) days to care for symptomatic children. Among children (aged ≤17 years), 35.0% stayed home sick from kindergarten/preschool or school/university for a mean of 5.2 (±3.8) days resulting in 5.1 (±4.4) days of absence from work per sick child shared between parents/guardians. The estimated total number of sick leave days was 50,000 for adults and 20,700 for children, with an estimated direct cost of €7 million for employers. The potential impact on society of sick leave caused by waterborne diseases must be considered in decisions regarding the quality of drinking water.

  • 23. Saffari, Fereshteh
    et al.
    Monsen, Tor
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Karmostaji, Afsaneh
    Azimabad, Fahimeh Bahadori
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Significant spread of extensively drug-resistant Acinetobacter baumannii genotypes of clonal complex 92 among intensive care unit patients in a university hospital in southern Iran2017In: Journal of Medical Microbiology, ISSN 0022-2615, E-ISSN 1473-5644, Vol. 66, no 11, p. 1656-1662Article in journal (Refereed)
    Abstract [en]

    Purpose: Infections associated with Acinetobacter baumannii represent an increasing threat in healthcare settings. Therefore, we investigated the epidemiological relationship between clinical isolates of A. baumannii obtained from patients in a university hospital in Bandar Abbas in southern Iran.

    Methodology: Sixty-four consecutive non-duplicate clinical isolates collected during 2014–2015 were subjected to susceptibility testing, clonal relationship analysis using PFGE, multilocus variable-number tandem-repeat analysis (MLVA) and multilocus sequence typing (MLST), and examined for the presence of carbapenemases and integrons.

    Results: Almost all A. baumannii isolates were extensively drug-resistant (XDR; 98 %) and carried an OXA carbapenemase gene (bla OXA-23-like; 98 %) and class 1 integrons (48 %). PFGE and MLST analysis identified three major genotypes, all belonging to clonal complex 92 (CC92): sequence type 848 (ST848) (n=23), ST451 (n=16) and ST195 (n=8). CC92 has previously been documented in the hospital setting in northern Iran, and ST195 has been reported in Arab States of the Persian Gulf. These data suggest national and global transmission of A. baumannii CC92.

    Conclusion: This report demonstrates the occurrence and potential spread of closely related XDR genotypes of A. baumannii CC92 within a university hospital in southern Iran. These genotypes were found in the majority of the investigated isolates, showed high prevalence of blaOXA-23 and integron class 1, and were associated with stay in the intensive care unit. Very few treatment options remain for healthcare-adapted XDR A. baumannii, and hence effective measures are desperately needed to reduce the spread of these strains and resultant infections in the healthcare setting.

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  • 24. 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.

  • 25. Sane, Jussi
    et al.
    Sorvari, Tiina
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Kauma, Heikki
    Kaukoniemi, Ulla
    Tarkka, Eveliina
    Puumalainen, Taneli
    Kuusi, Markku
    Salminen, Mika
    Lyytikäinen, Outi
    Respiratory diphtheria in an asylum seeker from Afghanistan arriving to Finland via Sweden, December 20152016In: Eurosurveillance, ISSN 1025-496X, E-ISSN 1560-7917, Vol. 21, no 2Article in journal (Refereed)
    Abstract [en]

    In December 2015, an asylum seeker originating from Afghanistan was diagnosed with respiratory diphtheria in Finland. He arrived in Finland from Sweden where he had already been clinically suspected and tested for diphtheria. Corynebacterium diphtheriae was confirmed in Sweden and shown to be genotypically and phenotypically toxigenic. The event highlights the importance of early case detection, rapid communication within the country and internationally as well as preparedness plans of diphtheria antitoxin availability.

  • 26. Sendi, P
    et al.
    Christensson, B
    Uçkay, I
    Trampuz, A
    Achermann, Y
    Boggian, K
    Svensson, D
    Widerström, Micael
    Department of Infectious Diseases, Östersund Hospital, Östersund, Sweden.
    Zimmerli, W
    Group B streptococcus in prosthetic hip and knee joint-associated infections2011In: Journal of Hospital Infection, ISSN 0195-6701, E-ISSN 1532-2939, Vol. 79, no 1, p. 64-69Article in journal (Refereed)
    Abstract [en]

    The incidence of invasive group B streptococcus (GBS) infections in non-pregnant adults is increasing. Little is known about GBS in periprosthetic joint infections (PJIs). We aimed to analyse the clinical presentation of GBS PJI and its treatment in association with the outcome. The characteristics of 36 GBS PJIs collected from 10 centres were investigated. In 34 episodes, follow-up examination of ≥ 2 years was available, allowing treatment and outcome analysis. Most infections (75%) occurred ≥ 3 months after implantation. Most patients (91%) had at least one comorbidity; 69% presented with acute symptoms and 83% with damaged periprosthetic soft tissue. In 20 of 34 episodes debridement and retention of implant was attempted, but in five of these the prosthesis was ultimately removed. Hence, in 19 (56%) episodes, the implant was removed, including 14 immediate removals. In four episodes the removal was permanent. Penicillin derivatives and clindamycin were the most common antimicrobials administered (68%). In 94% the infection was cured, and in 82% functional mobility preserved. Debridement with implant retention was successful if the duration of symptoms was short, the prosthesis stable, and the tissue damage minor (10/10 vs 3/10 episodes, P = 0.003). Surgery that complied with a published algorithm was associated with a favourable outcome (P = 0.049).

  • 27. Sharma, Sumit
    et al.
    Hagbom, Marie
    Carlsson, Beatrice
    Ohd, Joanna Nederby
    Insulander, Mona
    Eriksson, Ronnie
    Simonsson, Magnus
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology. Department of Communicable Disease Control and Prevention, Stockholm County Council, Stockholm, Sweden.
    Nordgren, Johan
    Secretor Status is Associated with Susceptibility to Disease in a Large GII.6 Norovirus Foodborne Outbreak2020In: Food and Environmnetal Virology, ISSN 1867-0334, E-ISSN 1867-0342, Vol. 12, p. 28-34Article in journal (Refereed)
    Abstract [en]

    Norovirus is commonly associated with food and waterborne outbreaks. Genetic susceptibility to norovirus is largely dependent on presence of histo-blood group antigens (HBGA), specifically ABO, secretor, and Lewis phenotypes. The aim of the study was to determine the association between HBGAs to norovirus susceptibility during a large norovirus foodborne outbreak linked to genotype GII.6 in an office-based company in Stockholm, Sweden, 2015. A two-episode outbreak with symptoms of diarrhea and vomiting occurred in 2015. An online questionnaire was sent to all 1109 employees that had worked during the first outbreak episode. Food and water samples were collected from in-house restaurant and tested for bacterial and viral pathogens. In addition, fecal samples were collected from 8 employees that had diarrhea. To investigate genetic susceptibility during the outbreak, 98 saliva samples were analyzed for ABO, secretor, and Lewis phenotypes using ELISA. A total of 542 of 1109 (49%) employees reported gastrointestinal symptoms. All 8 fecal samples tested positive for GII norovirus, which was also detected in coleslaw collected from the in-house restaurant. Eating at the in-house restaurant was significantly associated with risk of symptom development. Nucleotide sequencing was successful for 5/8 fecal samples and all belonged to the GII.6 genotype. HBGA characterization showed a strong secretor association to norovirus-related symptoms (P = 0.014). No association between norovirus disease and ABO phenotypes was observed. The result of this study shows that non-secretors were significantly less likely to report symptoms in a large foodborne outbreak linked to the emerging GII.6 norovirus strain.

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  • 28.
    Sjöström, Malin
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine.
    Arvidsson, M.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Söderström, L.
    Unit of Research, Education and Development–Östersund Hospital, Östersund, Sweden.
    Lilja, Mikael
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine.
    Lindh, J.
    Department of Cell and Molecular Biology, BMC, Uppsala University, Uppsala, Sweden.
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Outbreak of Cryptosporidium hominis in northern Sweden: persisting symptoms in a 5-year follow-up2022In: Parasitology Research, ISSN 0932-0113, E-ISSN 1432-1955, Vol. 121, p. 2043-2049Article in journal (Refereed)
    Abstract [en]

    In 2010–2011, a waterborne outbreak of the parasite, Cryptosporidium hominis, affected approximately 27,000 inhabitants in the city of Östersund, Sweden. Previous research suggested that post-infectious symptoms, such as gastrointestinal symptoms and joint pain, could persist for up to 2 years after the initial infection. In this study, we investigated whether the parasite caused post-infectious sequelae for up to 5 years after the outbreak. Prospective cohort study. A randomly selected cohort of individuals residing in Östersund at the time of the outbreak was sent a postal questionnaire in 2011. Responders were sent a follow-up questionnaire in 2016 and completed items on whether they experienced a list of symptoms. We examined whether outbreak cases were more likely than non-cases to report post-infectious symptoms 5 years later. We analysed data using logistic regression and calculated odds ratios with 95% confidence intervals. The analysis included 626 individuals. Among the 262 individuals infected during the outbreak, 56.5% reported symptoms at follow-up. Compared to non-cases, outbreak cases were more likely to report watery diarrhoea, diarrhoea, swollen joints, abdominal pain, bloating, joint discomfort, acid indigestion, alternating bowel habits, joint pain, ocular pain, nausea, and fatigue at the follow-up, after adjusting for age and sex. Our findings suggested that cryptosporidiosis was mainly associated with gastrointestinal- and joint-related post-infectious symptoms for up to 5 years after the infection.

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  • 29. Smith-Palmer, Alison
    et al.
    Oates, Ken
    Webster, Diana
    Taylor, Sarah
    Scott, Kevin J
    Smith, Gemma
    Parcell, Benjamin
    Lindstrand, Ann
    Wallensten, Anders
    Fredlund, Hans
    Widerström, Micael
    McMenamin, Jim
    Outbreak of Neisseria meningitidis capsular group W among scouts returning from the World Scout Jamboree, Japan, 20152016In: Eurosurveillance, ISSN 1025-496X, E-ISSN 1560-7917, Vol. 21, no 45Article in journal (Refereed)
    Abstract [en]

    The 23rd World Scout Jamboree was held in Japan from 28 July to 8 August 2015 and was attended by over 33,000 scouts from 162 countries. An outbreak of invasive meningococcal disease capsular group W was investigated among participants, with four confirmed cases identified in Scotland, who were all associated with one particular scout unit, and two confirmed cases in Sweden; molecular testing showed the same strain to be responsible for illness in both countries. The report describes the public health action taken to prevent further cases and the different decisions reached with respect to how wide to extend the offer of chemoprophylaxis in the two countries; in Scotland, chemoprophylaxis was offered to the unit of 40 participants to which the four cases belonged and to other close contacts of cases, while in Sweden chemoprophylaxis was offered to all those returning from the Jamboree. The report also describes the international collaboration and communication required to investigate and manage such multinational outbreaks in a timely manner.

  • 30.
    Vikström, Linnea
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Fjällström, Peter
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Gwon, Yong-Dae
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Sheward, Daniel J.
    The Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden.
    Wigren-Byström, Julia
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Evander, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Bladh, Oscar
    The Department of Clinical Sciences, Karolinska Institutet Danderyd Hospital, Stockholm, Sweden.
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Molnar, Christian
    Familjeläkarna, Stockholm, Sweden.
    Rasmussen, Gunlög
    School of Medical Sciences, Örebro University, Örebro, Sweden.
    Bennet, Louise
    Department of Clinical Sciences, Clinical Studies Sweden, Forum South, Skåne University Hospital, Lund University, Lund, Sweden.
    Åberg, Mikael
    The Department of Medical Sciences, Clinical Chemistry and SciLifeLab, Uppsala University, Uppsala, Sweden.
    Björk, Jonas
    The Division of Occupational and Environmental Medicine, Lund University, Lund, Sweden.
    Tevell, Staffan
    Faculty of Medicine and Health, The Department of Infectious Diseases, Karlstad Hospital and Centre for Clinical Research and Education, Region Värmland, Örebro University, Örebro, Sweden.
    Thålin, Charlotte
    The Department of Clinical Sciences, Karolinska Institutet Danderyd Hospital, Stockholm, Sweden.
    Blom, Kim
    The Swedish Public Health Agency, Stockholm, Sweden.
    Klingström, Jonas
    The Department of Biomedical Clinical Sciences, Linköpings University, Linköping, Sweden.
    Murrell, Ben
    The Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden.
    Ahlm, Clas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Normark, Johan
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Johansson, Anders F.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Forsell, Mattias N. E.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Vaccine-induced correlate of protection against fatal COVID-19 in older and frail adults during waves of neutralization-resistant variants of concern: an observational study2023In: The Lancet Regional Health: Europe, E-ISSN 2666-7762, Vol. 30, article id 100646Article in journal (Refereed)
    Abstract [en]

    Background: To inform future preventive measures including repeated vaccinations, we have searched for a clinically useful immune correlate of protection against fatal COVID-19 among nursing homes residents.

    Methods: We performed repeated capillary blood sampling with analysis of S-binding IgG in an open cohort of nursing home residents in Sweden. We analyzed immunological and registry data from 16 September 2021 to 31 August 2022 with follow-up of deaths to 30 September 2022. The study period included implementation of the 3rd and 4th mRNA monovalent vaccine doses and Omicron virus waves.

    Findings: A total of 3012 nursing home residents with median age 86 were enrolled. The 3rd mRNA dose elicited a 99-fold relative increase of S-binding IgG in blood and corresponding increase of neutralizing antibodies. The 4th mRNA vaccine dose boosted levels 3.8-fold. Half-life of S-binding IgG was 72 days. A total 528 residents acquired their first SARS-CoV-2 infection after the 3rd or the 4th vaccine dose and the associated 30-day mortality was 9.1%. We found no indication that levels of vaccine-induced antibodies protected against infection with Omicron VOCs. In contrast, the risk of death was inversely correlated to levels of S-directed IgG below the 20th percentile. The death risk plateaued at population average above the lower 35th percentile of S-binding IgG.

    Interpretation: In the absence of neutralizing antibodies that protect from infection, quantification of S-binding IgG post vaccination may be useful to identify the most vulnerable for fatal COVID-19 among the oldest and frailest. This information is of importance for future strategies to protect vulnerable populations against neutralization resistant variants of concern.

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  • 31.
    Werneke, Ursula
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Maripuu, Martin
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Bendix, Marie
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Öhlund, Louise
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Death associated with coronavirus (COVID-19) infection in individuals with severe mental disorders in sweden during the early months of the outbreak2021In: European psychiatry, ISSN 0924-9338, E-ISSN 1778-3585, Vol. 64, no S1, p. S119-S120, article id O145Article in journal (Other academic)
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  • 32.
    Widerstrom, Micael
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Wistrom, Johan
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Sjöstedt, Anders
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Monsen, Tor
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Coagulase-negative staphylococci: update on the molecular epidemiology and clinical presentation, with a focus on Staphylococcus epidermidis and Staphylococcus saprophyticus2012In: European Journal of Clinical Microbiology and Infectious Diseases, ISSN 0934-9723, E-ISSN 1435-4373, Vol. 31, no 1, p. 7-20Article, review/survey (Refereed)
    Abstract [en]

    Coagulase-negative staphylococci (CoNS), originally described as ubiquitous commensals of the healthy human skin and mucosa, have emerged as important opportunistic pathogens primarily causing healthcare-associated infections in patients with indwelling medical devices. Recent studies, utilizing new molecular typing methods, particularly on Staphylococcus epidermidis, have increased our understanding of the mechanisms that contribute to the evolutionary success of these extremely versatile microorganisms. In the following mini-review, we summarize recent research in this area focusing on the molecular methods and epidemiology of S. epidermidis and S. saprophyticus.

  • 33.
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology. Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Molecular epidemiology of coagulase-negative staphylococci in hospitals and in the community2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Background

    Coagulase-negative staphylococci (CoNS) and in particular Staphylococcus epidermidis have emerged as major pathogens primarily causing nosocomial infections in patients with indwelling medical devices. These infections are often caused by multidrug-resistant strains of S. epidermidis (MDRSE). Other clinical entities due to CoNS are lower urinary tract infections (UTI) in women and native valve endocarditis. The purpose of this work was to investigate the frequency of antibiotic resistance and the molecular epidemiology of both hospital and community-associated isolates of S. epidermidis in order to examine if certain clones are related to MDRSE infections. Furthermore, we aimed to explore if specific clones of S. saprophyticus are associated with UTI in women.

    Methods

    A total of 359 hospital-associated methicillin-resistant isolates of CoNS obtained from 11 hospitals in northern Europe and 223 community-associated staphylococcal isolates were examined. Furthermore, 126 isolates of S. saprophyticus isolated from women with uncomplicated UTI from five different locations in northern Europe were analyzed. Pulsed-field gel electrophoresis (PFGE) was used for genotyping. Additionally, some of the S. epidermidis isolates were analyzed with multilocus sequence typing (MLST). Antibiotic susceptibility was determined for all isolates by the disc diffusion test.

    Results

    293 of the 359 (82%) hospital-associated and 124 of the 223 (56%) community-associated isolates belonged to the species S. epidermidis. Among the hospital-associated S. epidermidis isolates, two dominating PFGE types (type A and B) were distinguished, comprising 78 (27%) and 51 (17%) isolates, respectively. Type A, which was detected in a Norwegian and eight Swedish hospitals, corresponded with a novel sequence type (ST215). Type B was discovered in a German, a Danish and seven Swedish hospitals and corresponded with ST2. In contrast, community-associated isolates of S. epidermidis were genetically extremely diverse with no predominating genotype, and showed a low rate of antibiotic resistance; only two (1.6%) methicillin-resistant strains were detected.

    Among 126 analyzed isolates of S. saprophyticus, 47 different PFGE profiles were identified. Several clusters of genetically highly related isolates were detected among isolates obtained from different locations and periods of time.

    Conclusion

    We have demonstrated the occurrence, persistence and potential dissemination of two multidrug-resistant S. epidermidis (MDRSE) genotypes, including a novel sequence type (ST215), within hospitals in northern Europe. Community-associated isolates of S. epidermidis showed a low rate of methicillin-resistance and were genetically heterogeneous. These results indicate that MDRSE by large are confined to the hospital setting in our region. Moreover, although the S. saprophyticus population was quite heterogeneous, indistinguishable isolates of S. saprophyticus causing lower UTI in women were identified in different countries 11 years apart, indicating the persistence and geographical spread of some clones of S. saprophyticus.

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  • 34.
    Widerström, Micael
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Significance of Staphylococcus epidermidis in Health Care-Associated Infections, from Contaminant to Clinically Relevant Pathogen: This Is a Wake-Up Call!2016In: Journal of Clinical Microbiology, ISSN 0095-1137, E-ISSN 1098-660X, Vol. 54, no 7, p. 1679-1681Article in journal (Refereed)
    Abstract [en]

    Coagulase-negative staphylococci, particularly Staphylococcus epidermidis, have been recognized as an important cause of health care-associated infections. Concurrently, S. epidermidis is a common contaminant in clinical cultures, which poses a diagnostic challenge. An article in this issue of Journal of Clinical Microbiology ( I. Tolo, J. C. Thomas, R. S. B. Fischer, E. L. Brown, B. M. Gray, and D. A. Robinson, J Clin Microbiol 54: 1711-1719, 2015, http://dx.doi.org/10.1128/JCM.03345-15) describes a rapid single nucleotide polymorphism-based assay for distinguishing between S. epidermidis isolates from hospital and nonhospital sources, which represents an important contribution to the characterization and understanding of S. epidermidis health care-associated infections.

  • 35.
    Widerström, Micael
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases. Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    McCullough, Cheryll A.
    Coombs, Geoffrey W.
    Monsen, Tor
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Christiansen, Keryn J.
    A Multidrug-Resistant Staphylococcus epidermidis Clone (ST2) Is an Ongoing Cause of Hospital-Acquired Infection in a Western Australian Hospital2012In: Journal of Clinical Microbiology, ISSN 0095-1137, E-ISSN 1098-660X, Vol. 50, no 6, p. 2147-2151Article in journal (Refereed)
    Abstract [en]

    We report the molecular epidemiology of 27 clinical multidrug-resistant Staphylococcus epidermidis (MDRSE) isolates collected between 2003 and 2007 in an Australian teaching hospital. The dominant genotype (sequence type 2 [ST2]) accounted for 85% of the isolates tested and was indistinguishable from an MDRSE genotype identified in European hospitals, which may indicate that highly adaptable health care-associated genotypes of S. epidermidis have emerged and disseminated worldwide in the health care setting.

  • 36.
    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.

  • 37.
    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.
    Wiström, Johan
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Molecular epidemiology of meticillin-resistant coagulase-negative staphylococci in a Swedish county hospital: evidence of intra- and interhospital clonal spread2006In: Journal of Hospital Infection, ISSN 0195-6701, E-ISSN 1532-2939, Vol. 64, no 2, p. 177-183Article in journal (Refereed)
    Abstract [en]

    During a 10-month period in 2003, consecutive routine clinical cultures from patients treated in 15 different ward units in a Swedish county hospital were screened for the presence of meticillin-resistant coagulase-negative staphylococci (CNS). Genetic similarity between isolates was analysed using pulsed-field gel electrophoresis (PFGE). The results were compared with multi-drug-resistant Staphylococcus epidermidis isolated previously at the tertiary referral hospital. In total, 428 isolates of CNS were identified, of which 188 (44%) were meticillin resistant. Three clusters (Groups A, B and C) of S. epidermidis, each consisting of more than 10 isolates, with a PFGE-DNA similarity of >90% were identified. The strains in Groups A and B (N=15 and N=13, respectively), which were generally resistant to gentamicin, co-trimoxazole and clindamycin, originated from 24 patients, of whom 21 had been treated in the intensive care unit (ICU) before sampling. The third cluster, Group C, involved 14 isolates from 14 patients. Only two of these patients had stayed at the ICU, and all for less than one day. Isolates in Group C were less resistant than those in Groups A and B. Isolates belonging to Group A showed an identical PFGE profile compared with multi-drug-resistant S. epidermidis isolated from patients at the referral hospital. This study demonstrated the persistence and spread of meticillin-resistant clones of CNS within the county hospital, especially in the ICU, and possible interhospital spread of a multi-drug-resistant clone between the county and referral hospitals.

  • 38.
    Widerström, Micael
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Mörtberg, Sara
    Department of Infectious Diseases, Östersund Hospital, Östersund, Sweden.
    Magnusson, Mattias
    Department of Radiology, Östersund Hospital, Östersund, Sweden.
    Fjällström, Peter
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Johansson, Anders
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Treatment outcome of severe respiratory type B tularemia using fluoroquinolones2024In: Clinical Infectious Diseases, ISSN 1058-4838, E-ISSN 1537-6591, Vol. 78, p. S38-S46Article in journal (Refereed)
    Abstract [en]

    Background: Fluoroquinolones lack approval for treatment of tularemia but have been used extensively for milder illness. Here, we evaluated fluoroquinolones for severe illness.

    Methods: In an observational study, we identified case-patients with respiratory tularemia from July to November 2010 in Jämtland County, Sweden. We defined severe tularemia by hospitalization for >24 hours and severe bacteremic tularemia by Francisella tularensis subsp. holarctica growth in blood or pleural fluid. Clinical data and drug dosing were retrieved from electronic medical records. Chest images were reexamined. We used Kaplan-Meier curves to evaluate time to defervescence and hospital discharge.

    Results: Among 67 case-patients (median age, 66 years; 81% males) 30-day mortality was 1.5% (1 of 67). Among 33 hospitalized persons (median age, 71 years; 82% males), 23 had nonbacteremic and 10 had bacteremic severe tularemia. Subpleural round consolidations, mediastinal lymphadenopathy, and unilateral pleural fluid were common on chest computed tomography. Among 29 hospitalized persons with complete outcome data, ciprofloxacin/levofloxacin (n = 12), ciprofloxacin/levofloxacin combinations with doxycycline and/or gentamicin (n = 11), or doxycycline as the single drug (n = 6) was used for treatment. One disease relapse occurred with doxycycline treatment. Treatment responses were rapid, with median fever duration 41.0 hours in nonbacteremic and 115.0 hours in bacteremic tularemia. Increased age-adjusted Charlson comorbidity index predicted severe bacteremic tularemia (odds ratio, 2.7 per score-point; 95% confidence interval, 1.35-5.41). A 78-year-old male with comorbidities and delayed ciprofloxacin/gentamicin treatment died.

    Conclusions: Fluoroquinolone treatment is effective for severe tularemia. Subpleural round consolidations and mediastinal lymphadenopathy were typical findings on computed tomography among case-patients in this study.

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  • 39.
    Widerström, Micael
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases. Jämtland Cty Council, Östersund, Sweden.
    Schönning, Caroline
    Lilja, Mikael
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine.
    Lebbad, Marianne
    Ljung, Thomas
    Allestam, Görel
    Ferm, Martin
    Björkholm, Britta
    Hansen, Anette
    Hiltula, Jan I.
    Långmark, Jonas
    Löfdahl, Margareta
    Omberg, Maria
    Reuterwall, Christina
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Samuelsson, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine.
    Widgren, Katarina
    Wallensten, Anders
    Lindh, Johan
    Large outbreak of cryptosporidium hominis infection transmitted through the public water supply, Sweden2014In: Emerging Infectious Diseases, ISSN 1080-6040, E-ISSN 1080-6059, Vol. 20, no 4, p. 581-589Article in journal (Refereed)
    Abstract [en]

    In November 2010, approximate to 27,000 (approximate to 45%) inhabitants of Östersund, Sweden, were affected by a waterborne outbreak of cryptosporidiosis. The outbreak was characterized by a rapid onset and high attack rate, especially among young and middle-aged persons. Young age, number of infected family members, amount of water consumed daily, and gluten intolerance were identified as risk factors for acquiring cryptosporidiosis. Also, chronic intestinal disease and young age were significantly associated with prolonged diarrhea. Identification of Ctyptosporidium hominis subtype lbA10G2 in human and environmental samples and consistently low numbers of oocysts in drinking water confirmed insufficient reduction of parasites by the municipal water treatment plant. The current outbreak shows that use of inadequate microbial barriers at water treatment plants can have serious consequences for public health. This risk can be minimized by optimizing control of raw water quality and employing multiple barriers that remove or inactivate all groups of pathogens.

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  • 40.
    Widerström, Micael
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Stegger, Marc
    Johansson, Anders
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Gurram, Bharat Kumar
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Larsen, Anders Rhod
    Wallinder, Lars
    Edebro, Helen
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Monsen, Tor
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Heterogeneity of Staphylococcus epidermidis in prosthetic joint infections: time to reevaluate microbiological criteria?2022In: European Journal of Clinical Microbiology and Infectious Diseases, ISSN 0934-9723, E-ISSN 1435-4373, Vol. 41, p. 87-97Article in journal (Refereed)
    Abstract [en]

    Prosthetic joint infection (PJI) is a feared and challenging to diagnose complication after arthroplasty, with Staphylococcus epidermidis as the major pathogen. One important criteria to define PJI is the detection of phenotypically indistinguishable microorganisms with identical antibiotic susceptibility pattern in at least two different samples. However, owing to phenotypical variation within genetic clones and clonal variation within a phenotype, the criteria may be ambiguous. We investigated the extent of diversity among coagulase-negative staphylococci (CoNS) in PJI and characterised S. epidermidis isolates from PJI samples, specifically multiple S. epidermidis isolates identified in individual PJI patients. We performed a retrospective cohort study on 62 consecutive patients with PJI caused by CoNS from two hospitals in Northern Sweden. In 16/62 (26%) PJIs, multiple S. epidermidis isolates were available for whole-genome analyses. Hospital-adapted multidrug-resistant genetic clones of S. epidermidis were identified in samples from 40/62 (65%) of the patients using a combination of pulsed-field gel electrophoresis and multilocus sequence typing. Whole-genome sequencing showed the presence of multiple sequence types (STs) in 7/16 (44%) PJIs where multiple S. epidermidis isolates were available. Within-patient phenotypical variation in the antibiotic susceptibility and/or whole-genome antibiotic resistance gene content was frequent (11/16, 69%) among isolates with the same ST. The results highlight the ambiguity of S. epidermidis phenotypic characterisation as a diagnostic method in PJI and call for larger systematic studies for determining the frequency of CoNS diversity in PJIs, the implications of such diversity for microbiological diagnostics, and the therapeutic outcomes in patients.

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  • 41.
    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, 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.

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  • 42.
    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.

  • 43.
    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.
    Wiström, Johan
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Infectious Diseases.
    Ferry, Sven
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Karlsson, Carina
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology. Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Monsen, Tor
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology. Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Molecular epidemiology of Staphylococcus saprophyticus isolated from women with uncomplicated community-acquired urinary tract infection2007In: Journal of Clinical Microbiology, ISSN 0095-1137, E-ISSN 1098-660X, Vol. 45, no 5, p. 1561-1564Article in journal (Refereed)
    Abstract [en]

    Staphylococcus saprophyticus is a common cause of urinary tract infections (UTIs) in women. Little is known about the molecular epidemiology of S. saprophyticus UTIs. In the current study, we compared 76 isolates of S. saprophyticus prospectively isolated from women with uncomplicated UTI participating in a randomized placebo-controlled treatment trial performed in northern Sweden from 1995 to 1997 with 50 strains obtained in 2006 from five different locations in northern Europe with pulsed-field gel electrophoresis (PFGE). The aim was to elucidate the molecular epidemiology of this uropathogenic species and to investigate whether specific clones are associated with UTI in women. A total of 47 different PFGE profiles were detected among the 126 analyzed isolates. Ten clusters consisting of 5 to 12 isolates each showing PFGE DNA similarity of >85% were identified. Several clusters of genetically highly related isolates were detected in the original trial as well as among isolates obtained during 2006 from different locations. In the original trial, clonal persistence was found among 16 of 21 (76%) patients examined in the placebo group at follow-up 8 to 10 days after inclusion, indicating a low spontaneous short-time bacteriological cure rate. We conclude that multiple clones of S. saprophyticus were causing lower UTIs in women. The result suggests that some human-pathogenic clones of S. saprophyticus are spread over large geographical distances and that such clones may persist over long periods of time.

  • 44. Widgren, K
    et al.
    Magnusson, M
    Hagstam, P
    Widerström, Micael
    Department of Communicable Disease Control and Prevention Jämtland County, Östersund, Sweden.
    Örtqvist, Åke
    Einemo, Im
    Follin, P
    Lindblom, A
    Mäkitalo, S
    Wik, O
    Österlund, A
    Grünewald, M
    Uhnoo, Ingrid
    Linde, A
    Prevailing effectiveness of the 2009 influenza A(H1N1)pdm09 vaccine during the 2010/11 season in Sweden2013In: Eurosurveillance, ISSN 1025-496X, E-ISSN 1560-7917, Vol. 18, no 15, p. Article 5-Article in journal (Refereed)
    Abstract [en]

    Sixty per cent of the Swedish population received the monovalent AS03-adjuvanted pandemic influenza vaccine in the autumn of 2009. We assessed the age-specific effectiveness of this pandemic vaccine against hospitalisation with laboratory-confirmed influenza A(H1N1)pdm09 during the season 2010/11, in the age group from six months to 64 years in Sweden. The screening method was applied to available surveillance data. Our results suggest a prevailing effectiveness of 72% (95% confidence interval (CI): 63–80%) with the highest effectiveness among children, six months to nine years-old (92%, 95%CI: 80–97%). However, there were limitations in data quality and study design due to the lack of systematic recording of administered vaccinations, which underline the importance of preparing for an evaluation when planning for large public health actions. Despite these limitations, we believe the results reflect true, high prevailing vaccine effectiveness. Indeed, there were fewer deaths caused by influenza and the impact of influenza on intensive care units was less severe during the 2010/11 season in Sweden than in countries with lower pandemic vaccination coverage. The association between the pandemic vaccine and narcolepsy has increased the importance of assessing the risks and benefits of the vaccination; studies on the effectiveness and the duration of protection are needed for this.

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