Increasing burden of invasive group B streptococcal disease in nonpregnant adults, 1990-2007.
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.
Skoff
Tami H
TH
National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA. tlh9@cdc.gov
Farley
Monica M
MM
Petit
Susan
S
Craig
Allen S
AS
Schaffner
William
W
Gershman
Ken
K
Harrison
Lee H
LH
Lynfield
Ruth
R
Mohle-Boetani
Janet
J
Zansky
Shelley
S
Albanese
Bernadette A
BA
Stefonek
Karen
K
Zell
Elizabeth R
ER
Jackson
Delois
D
Thompson
Terry
T
Schrag
Stephanie J
SJ
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