Evaluation of vaginal group B streptococcal culture results after digital vaginal examination and its pattern of antibiotic resistance in pregnant women

Background: Group B streptococcus (GBS) colonizes the gastrointestinal and genitourinary tract of 10-40% of pregnant women and it is a major cause of neonatal morbidity and mortality. Objective: This study was to evaluate whether vaginal GBS culture results alter after digital vaginal examination or not. Antibiotic resistance pattern of this specie has been also assessed. Materials and Methods: A total of 186 pregnant women with gestational age of 37 weeks were enrolled to the study. Two vaginal swaps were taken before and immediately after digital vaginal examination, then third swap was taken after 48 hours of examination. The cultures were evaluated for bacterial growth and the isolated bacteria were assessed for antimicrobial drugs sensitivity. Results: Positive culture of GBS was seen in 16.1%. Initially negative GBS result was found not to change immediately after examination. But positive cultures were negative in 1.6% of women after digital vaginal examination. After 48 hours 2.7% of initially negative GBS was positive and no one with initially positive GBS had negative culture. Sensitivity to penicillin and vancomycin was 100%, erythromycin 74%, ampicillin 65%, cefazolin 62.8%, cefotaxime 54.2% and ceftizoxime was 40%. Conclusion: The present investigation showed that the vaginal GBS culture result is minimally affected by digital vaginal examination. Drug of choice for GBS eradication is penicillin; vancomycin could be the choice in the case of penicillin hypersensitivity. This article extracted from M.D. thesis. (Mahdokht Sadat Manavi)