title: The changing epidemiology of group B streptococcus bloodstream infection: a multi-national population-based assessment.
abstract: BACKGROUND
  Population-based studies conducted in single regions or countries have identified significant changes in the epidemiology of invasive group B streptococcus (GBS) infection. However, no studies have concurrently compared the epidemiology of GBS infections among multiple different regions and countries over time. The study objectives were to define the contemporary incidence and determinants of GBS bloodstream infection (BSI) and assess temporal changes in a multi-national population.
  
  
  METHODS
  Population-based surveillance for GBS BSI was conducted in nine regions in Australia, Canada, Denmark, Sweden, Finland and the UK during 2000-2010. Incidence rates were age- and gender-standardised to the EU population.
  
  
  RESULTS
  During 114 million patient-years of observation, 3464 cases of GBS BSI were identified for an overall annual incidence of 3.4 patients per 100,000 persons. There were marked differences in the overall (range = 1.8-4.1 per 100,000 person-year) and neonatal (range = 0.19-0.83 per 1000 live births) incidences of GBS BSI observed among the study regions. The overall incidence significantly (p = 0.05) increased. Rates of neonatal disease were stable, while the incidence in individuals older than 60 years doubled (p = 0.003). In patients with detailed data (n = 1018), the most common co-morbidity was diabetes (25%). During the study period, the proportion of cases associated with diabetes increased.
  
  
  CONCLUSIONS
  While marked variability in the incidence of GBS BSI was observed among these regions, it was consistently found that rates increased among older adults, especially in association with diabetes. The burden of this infection may be expected to continue to increase in ageing populations worldwide.
authors.affiliation: a Department of Medicine , University of Calgary , Calgary , Alberta , Canada ;
authors.forename: Mark S
authors.initials: MS
authors.lastname: Ballard
authors.affiliation: b Department of Clinical Microbiology , Aarhus University Hospital , Aalborg , Denmark ;|c Department of Clinical Medicine , Aalborg University , Aalborg , Denmark ;
authors.forename: Henrik C
authors.initials: HC
authors.lastname: Schønheyder
authors.affiliation: d Department of Clinical Microbiology , Copenhagen University Hospital, Hvidovre Hospital , Copenhagen , Denmark ;
authors.forename: Jenny Dahl
authors.initials: JD
authors.lastname: Knudsen
authors.affiliation: e Department of Infectious Disease Surveillance and Control , National Institute for Health and Welfare , Helsinki , Finland ;
authors.forename: Outi
authors.initials: O
authors.lastname: Lyytikäinen
authors.affiliation: f Department of Microbiology , Royal Hampshire County Hospital, Hampshire Hospitals NHS Foundation Trust , Winchester , UK ;
authors.forename: Matthew
authors.initials: M
authors.lastname: Dryden
authors.affiliation: g Department of Infectious Disease and Microbiology , Canberra Hospital and Health Services, Australian National University Medical School , Australia ;
authors.forename: Karina J
authors.initials: KJ
authors.lastname: Kennedy
authors.affiliation: h Department of Microbiology and Infectious Diseases , Université de Sherbrooke , Sherbrooke , Québec , Canada ;
authors.forename: Louis
authors.initials: L
authors.lastname: Valiquette
authors.affiliation: i Department of Clinical Microbiology , Copenhagen University Hospital, Herlev Hospital , Copenhagen , Denmark ;
authors.forename: Mette
authors.initials: M
authors.lastname: Pinholt
authors.affiliation: j Department of Infectious Diseases , Skaraborg Hospital , Skövde , Sweden ;
authors.forename: Gunnar
authors.initials: G
authors.lastname: Jacobsson
authors.affiliation: a Department of Medicine , University of Calgary , Calgary , Alberta , Canada ;|k Department of Medicine , Royal Inland Hospital , Kamloops , British Columbia , Canada.
authors.forename: Kevin B
authors.initials: KB
authors.lastname: Laupland
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001315:Australia / Q000453:epidemiology; D016470:Bacteremia / Q000453:epidemiology* / Q000382:microbiology*; D002170:Canada / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D005060:Europe / Q000453:epidemiology; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance; D013290:Streptococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D013292:Streptococcus agalactiae; D055815:Young Adult
keywords: Group B streptococcus; diabetes; epidemiology; neonatal sepsis; population-based study; streptococcus agalactiae