Group B Streptococcus agalactiae resistant to recommended intrapartum antibiotic prophylaxis isolated from the rectovaginal area of 35-37 weeks pregnant women

Aims: Group B Streptococcus (GBS; Streptococcus agalactiae) is naturally found in the gut of humans and other warmblooded animals. GBS asymptomatically colonizes the rectovaginal area of pregnant women and it has been identified as a significant risk factor for neonatal disease and mortality. This study was aimed to characterize GBS isolates isolated from pregnant women in Eastern Cape, South Africa. Methodology and results: A total of 82 pregnant women in their third trimester (35-37 weeks) of gestation were screened for GBS. GBS strains were isolated from rectovaginal swabs using standard microbiological methods on Todd-Hewitt broth and blood agar, from which presumptive isolates with p-haemolysis were confirmed by polymerase chain reaction (PCR). The confirmed GBS isolates were further delineated into serogroups by PCR. An antimicrobial susceptibility profiling was carried out on the isolates, followed by resistance gene profiling on resistant isolates by PCR. A total of 49 (60%) out of 82 pregnant women were colonized with GBS. The prevalence of the serogroups that were identified were serogroup Ib 2 (4.8%), serogroup II 20 (40.8%) and serogroup IV 5 (10.2%), and non-typable 22 (44.9%). All confirmed GBS isolates (49) were resistant to erythromycin, tetracycline and clindamycin, and MAR and MARI ranged from 5-7 and 0.4-0.7, respectively. The genes responsible for conferring resistance to erythromycin, tetracycline and penicillin were successfully amplified, while no genes associated with resistance to vancomycin and clindamycin were detected. Conclusion, significance and impact of study: Research findings of this study showed that serogroup Ib 2 (4.8%), serogroup II 20 (40.8%), serogroup IV 5 (10.2%) and non-typable 22 (44.9%) were the prevalent GBS serogroups. A high prevalence of antibiotics resistances was observed among the isolates, thus posing a threat to public health as it limits treatment options.