title: Increasing burden of invasive group B streptococcal disease in nonpregnant adults, 1990-2007.
abstract: BACKGROUND
  Group B Streptococcus (GBS), traditionally considered to be a neonatal pathogen, is an important cause of morbidity and mortality among older adults and among those with underlying medical conditions. We used population-based surveillance to examine trends in adult GBS disease during the period 1990-2007 and to describe the epidemiology of adult GBS disease to guide prevention efforts.
  
  
  METHODS
  Active Bacterial Core surveillance was conducted in selected counties in 10 US states. A case was defined as isolation of GBS from a normally sterile site in a nonpregnant resident of a surveillance area who was 18 years of age. Rates were calculated using US Census data. Demographic and clinical information was abstracted from medical records. Serotyping and susceptibility testing were performed on isolates collected from a subset of case patients.
  
  
  RESULTS
  A total of 19,512 GBS cases were identified in nonpregnant adults during 1990-2007 (median patient age, 63 years); the incidence of adult GBS disease doubled from 3.6 cases per 100,000 persons during 1990 to 7.3 cases per 100,000 persons during 2007 (P < .001). The mean difference in incidence between black and white persons was 4.6 cases per 100,000 persons (range, 3.1 cases per 100,000 persons during 1991 to 5.8 cases per 100,000 persons during 1999). Common clinical syndromes in 2007 included bacteremia without focus (39.3%), skin and/or soft-tissue infection (25.6%), and pneumonia (12.6%). Most (88.0%) GBS cases in adults had 1 underlying condition; diabetes was present in 44.4% of cases. Serotypes V, Ia, II, and III accounted for 80.8% of infections during 1998-1999 and 78.5% of infections during 2005-2006.
  
  
  CONCLUSIONS
  Invasive GBS disease in nonpregnant adults represents a substantial and increasing burden, particularly among older persons, black persons, and adults with diabetes. Prevention strategies are needed.
authors.affiliation: National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA. tlh9@cdc.gov
authors.forename: Tami H
authors.initials: TH
authors.lastname: Skoff
authors.forename: Monica M
authors.initials: MM
authors.lastname: Farley
authors.forename: Susan
authors.initials: S
authors.lastname: Petit
authors.forename: Allen S
authors.initials: AS
authors.lastname: Craig
authors.forename: William
authors.initials: W
authors.lastname: Schaffner
authors.forename: Ken
authors.initials: K
authors.lastname: Gershman
authors.forename: Lee H
authors.initials: LH
authors.lastname: Harrison
authors.forename: Ruth
authors.initials: R
authors.lastname: Lynfield
authors.forename: Janet
authors.initials: J
authors.lastname: Mohle-Boetani
authors.forename: Shelley
authors.initials: S
authors.lastname: Zansky
authors.forename: Bernadette A
authors.initials: BA
authors.lastname: Albanese
authors.forename: Karen
authors.initials: K
authors.lastname: Stefonek
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Zell
authors.forename: Delois
authors.initials: D
authors.lastname: Jackson
authors.forename: Terry
authors.initials: T
authors.lastname: Thompson
authors.forename: Stephanie J
authors.initials: SJ
authors.lastname: Schrag
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016470:Bacteremia / Q000453:epidemiology / Q000382:microbiology; D015373:Bacterial Typing Techniques; D044383:Black People; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D018410:Pneumonia, Bacterial / Q000453:epidemiology / Q000382:microbiology; D012703:Serotyping; D017192:Skin Diseases, Bacterial / Q000453:epidemiology / Q000382:microbiology; D018461:Soft Tissue Infections / Q000453:epidemiology / Q000382:microbiology; D013290:Streptococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D013292:Streptococcus agalactiae / Q000145:classification* / Q000302:isolation & purification*; D014481:United States / Q000453:epidemiology; D044465:White People; D055815:Young Adult; D001741:Black or African American