RELAPSING INVASIVE GROUP-B STREPTOCOCCAL INFECTION IN ADULTS

Objective: To study recurrent group B streptococcal infection in adults. Design: Patients with more than one reported group B streptococcal infection were identified through active surveillance for this infection. Sterile-site group B streptococcal isolates were evaluated for serotype and molecular subtyping using restriction endonuclease analysis of chromosomal DNA (REAC). Setting: All acute-care hospitals in Maryland. Patients: Nonpregnant residents of Maryland 18 years of age or older. Results: 22 adults had at least two group B streptococcal episodes that were separated by 2 to 95 weeks (mean, 24 weeks). Of 395 patients with invasive group B streptococcal infection who survived the first episode and were followed for at least 1 year, 17 (4.3% [95% CI, 2.6% to 6.9%]) had more than one episode. Several patients were found to have endocarditis or osteomyelitis during the second episode. Group B streptococcal isolates from both episodes were obtained from 18 of 22 patients. Of the 18 isolate pairs, 13 (72% [CI, 46% to 90%]) had identical REAC patterns; the probability that at least 13 matches would be found by chance alone was less than 0.00001. Among patients with recurrent infection caused by the same strain, the interval between episodes was shorter (mean, 14 weeks) than that among patients with recurrent infection caused by another strain (mean, 43 weeks; P = 0.05). Conclusions: Recurrent group B streptococcal infection is common among adults and in most cases appears to be caused by relapse. The optimal management of adults with a first episode of group B streptococcal infection needs to be further defined to minimize the likelihood of recurrent disease.