Antibiotic resistance patterns of group B streptococcus in antenatal genital cultures.

OBJECTIVE: To identify the antibiotic susceptibility patterns of group B streptococcus (GBS) isolated from antenatal genital screening cultures. STUDY DESIGN: One hundred thirty-five sequential GBS isolates underwent susceptibility testing by Kirby-Bauer disk diffusion to a variety of commonly used antibiotics. RESULTS: All isolates were susceptible to cefazolin, chloramphenicol and vancomycin. Resistance to clindamycin and erythromycin, the currently recommended alternative antibiotics for intrapartum GBS prophylaxis in penicillin-allergic women, was found in 8.2% and 9.6% of GBS isolates tested, respectively. CONCLUSION: These findings raise concerns regarding the need for both confirmation of a history of penicillin allergy in pregnant women and performance of antibiotic susceptibility testing on GBS isolated in genital screening cultures from penicillin-allergic patients.