Epidemiology of invasive group B streptococcal disease in the United States, 1999-2005.
BACKGROUND
Group B streptococcus is a leading infectious cause of morbidity in newborns and causes substantial disease in elderly individuals. Guidelines for prevention of perinatal disease through intrapartum chemoprophylaxis were revised in 2002. Candidate vaccines are under development.


OBJECTIVE
To describe disease trends among populations that might benefit from vaccination and among newborns during a period of evolving prevention strategies.


METHODS
Analysis of active, population-based surveillance in 10 states participating in the Active Bacterial Core surveillance/Emerging Infections Program Network.


METHODS
Age- and race-specific incidence of invasive group B streptococcal disease.


RESULTS
There were 14,573 cases of invasive group B streptococcal disease during 1999-2005, including 1348 deaths. The incidence of invasive group B streptococcal disease among infants from birth through 6 days decreased from 0.47 per 1000 live births in 1999-2001 to 0.34 per 1000 live births in 2003-2005 (P < .001), a relative reduction of 27% (95% confidence interval [CI], 16%-37%). Incidence remained stable among infants aged 7 through 89 days (mean, 0.34 per 1000 live births) and pregnant women (mean, 0.12 per 1000 live births). Among persons aged 15 through 64 years, disease incidence increased from 3.4 per 100,000 population in 1999 to 5.0 per 100,000 in 2005 (chi2(1) for trend, 57; P < .001), a relative increase of 48% (95% CI, 32%-65%). Among adults 65 years or older, incidence increased from 21.5 per 100,000 to 26.0 per 100,000 (chi2(1) for trend, 15; P < .001), a relative increase of 20% (95% CI, 8%-35%). All 4882 isolates tested were susceptible to penicillin, ampicillin, and vancomycin, but 32% and 15% were resistant to erythromycin and clindamycin, respectively. Serotypes Ia, Ib, II, III, and V accounted for 96% of neonatal cases and 88% of adult cases.


CONCLUSIONS
Among infants from birth through 6 days, the incidence of group B streptococcal disease was lower in 2003-2005 relative to 1999-2001. This reduction coincided with the release of revised disease prevention guidelines in 2002. However, the disease burden in adults is substantial and increased significantly during the study period.
Phares
Christina R
CR
Epidemic Intelligence Service Program, Office of Workforce and Career Development, Division of Bacterial Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA. cphares@cdc.gov
Lynfield
Ruth
R
Farley
Monica M
MM
Mohle-Boetani
Janet
J
Harrison
Lee H
LH
Petit
Susan
S
Craig
Allen S
AS
Schaffner
William
W
Zansky
Shelley M
SM
Gershman
Ken
K
Stefonek
Karen R
KR
Albanese
Bernadette A
BA
Zell
Elizabeth R
ER
Schuchat
Anne
A
Schrag
Stephanie J
SJ
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D002648:Child; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D011159:Population Surveillance; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000453:epidemiology; D012703:Serotyping; D013290:Streptococcal Infections / Q000453:epidemiology* / Q000517:prevention & control; D022541:Streptococcal Vaccines; D013292:Streptococcus agalactiae / Q000145:classification / Q000187:drug effects; D014481:United States / Q000453:epidemiology
D022541:Streptococcal Vaccines