Change in antibiotic resistance of group B streptococcus: impact on intrapartum management.

OBJECTIVE

Intrapartum chemoprophylaxis has resulted in a significant reduction of group B Streptococcus neonatal infection. For penicillin-allergic patients, clindamycin or erythromycin is the recommended antibiotic. The purpose of this study was to establish any pattern of antibiotic resistance of group B streptococcal clinical isolates over the past 15 years.

STUDY DESIGN

Group B streptococcal isolates obtained from the lower genital tract were tested for sensitivity to ampicillin, penicillin, clindamycin, and erythromycin. The sensitivity of 100 group B streptococcal isolates retrieved in the period 1997-1998 was compared with that of 85 group B streptococcal isolates from 1980-1993.

RESULTS

From 1980-1993 group B streptococcal isolates were available for testing for antibiotic resistance along with 100 isolates from a second study period 1997-1998. Of the 100 group B streptococcal isolates from 1997-1998, 18 were resistant to erythromycin, of which 5 were also resistant to clindamycin, as compared with 1 of the 85 isolates from 1980-1993 that was resistant to erythromycin (P <.001). All the isolates were sensitive to ampicillin and penicillin. All 18 resistant strains from 1997-1998 were found to be sensitive to cephalothin.

CONCLUSION

Over the past 18 years there has been increased in vitro resistance of group B streptococci to both clindamycin and erythromycin. If other studies confirm these findings, modifications to the current Centers for Disease Control and Prevention recommendations may be necessary.