Objective: To determine risk factors for community-acquired and nosocomial group B streptococcal disease in adults.
Design: Case-control study.
Setting: 3 metropolitan areas in the United States with an aggregate population of 6.6 million persons.
Patients: 219 nonpregnant adults with invasive group B streptococcal infection identified by a population-based surveillance in 1991 and 1992 and 645 hospital-matched controls.
Results: The following conditions were associated with a significantly increased risk for community-acquired group B streptococcal infection after controlling for age in multivariate analysis: cirrhosis (odds ratio, 9.7 [95% CI, 3.5 to 26.9]; P < 0.001), diabetes (odds ratio, 3.0 [CI, 1.9 to 4.7]; P < 0.001), stroke (odds ratio, 3.5 [CI, 1.9 to 6.4]; P < 0.001), breast cancer (odds ratio, 4.0 [CI, 1.6 to 9.8]; P = 0.002), decubitus ulcer (odds ratio, 4.0 [CI, 1.6 to 9.8]; P = 0.002), and neurogenic bladder (odds ratio, 4.6 [CI, 1.4 to 15.1]; P = 0.01). Sixty-three percent of community case-patients had at least one of these conditions. Nosocomial infection (48 cases [22%]) was independently associated with the placement of a central venous line (odds ratio, 30.9 [CI, 5.2 to 184.1]; P < 0.001), diabetes, congestive heart failure, and seizure disorder.
Conclusions: Several chronic conditions were independently associated with group B streptococcal disease, and most case-patients had at least one of these conditions. If group B streptococcal vaccines being developed for prevention of neonatal disease are protective in adults, a vaccination strategy targeting those at highest risk has the potential to substantially reduce the burden of invasive group B streptococcal infection in adults.