Group B Streptococcal Colonisation among Antenatal Women from a Tertiary Care Centre, Northern Kerala: A Cross-sectional Study

Introduction: Group B Streptococcus (GBS) is the leading cause of neonatal sepsis all over the world. Maternal colonisation of GBS in vaginal and anorectal area poses risk for subsequent invasive disease. The prevalence of maternal colonisation varies with geographical, biological and socio-economical factors. Current recommendations consider maternal screening and antibiotic therapy to prevent GBS neonatal disease with a potential of alteration of infant gut flora. Aim: To find out the prevalence, outcome and antimicrobial susceptibility pattern of the GBS colonisation in antenatal women. Materials and Methods: A hospital-based descriptive crosssectional study was conducted in Government Medical College, Kozhikode, Kerala, India, during December 2017 to May 2019 including 300 antenatal women of 35-37 weeks gestational age. Vaginal and rectal swabs were taken and were subjected to microbiological examination and culture. Data analysis was done by Statistical Package for the Social Sciences (SPSS) version 16.0. The Chi-square test and Fisher’s exact test were used wherever applicable and p-value <0.05 is considered significant. Results: Among the 300 antenatal women, 8 (2.7%) were colonised with GBS. Higher rate of colonisation was observed in women of 21-25 years, higher parity, rural dwelling and in women with poor glycaemic control. All the colonised women received antibiotic prophylaxis with intravenous ampicillin. None of the colonised women or the neonates born to them developed any invasive GBS infection. Antibiotic susceptibility testing showed that all the isolates were sensitive to penicillin, ampicillin and vancomycin but only 62.5% of the isolates were susceptible to clindamycin and 37.5% of the isolates were susceptible to erythromycin. Conclusion: The prevalence of GBS colonisation is low in Asian countries, compared to the data from western countries. Evidence based usage of narrow spectrum antibiotics should be considered. Further studies regarding prevalence, antibiotic susceptibility pattern, cost benefit analysis of the antibiotic usage and its effect on neonatal gut flora etc, including a wider population, is a need of the hour in the setting of emergence of resistance.