Rapid detection and antibiotic resistance of Group B Streptococcus from women at Kawempe Hospital Kampala, Uganda

Abstract

An accurate and rapid bedside test undertaken in labour ward to detect Group B Streptococcus (GBS) maternal colonization has the potential to improve the effectiveness of intrapartum antibiotic prophylaxis prevention strategies, especially in countries like Uganda, where antenatal testing would not be practical. The study evaluated the diagnostic accuracy of the Hibergene LAMP (HG GBS) assay for GBS detection using Todd Hewitt (LIM) broth and direct swab samples in a cohort of Ugandan women. Antimicrobial resistance profiles of GBS isolates from the same cohort were also described. Rectal and vaginal swabs were collected from 647 pregnant women and 83 non-pregnant women attending Kawempe Hospital, Kampala Uganda. One set of the swabs were tested directly by HG GBS and the other set were sent to the Medical Research Council laboratories and inoculated in LIM and after 24hours of incubation, tested by HG GBS and culture using chromogenic agar. Samples with discordant results were re-tested using the Allplex Meningitis-B assay (Allplex) that targets the CAMP factor (cfb) gene of GBS. Antibiotic susceptibility was determined by the Kirby Bauer disc diffusion method following EUCAST guidelines. Data was analyzed using Stata version15 software. The sensitivity and specificity of the HG GBS assay using LIM were 98.64% (95% CI, 95.17% - 99.83%) and 78.92% (95% CI, 76.43%-81.26 respectively. For direct swab samples, the sensitivity and specificity were 91.11% (95% CI, 78.78% - 97.52%) and 77.69% (95% CI, 69.22% - 84.75%) respectively. There was 87% agreement between Allplex and HG GBS results. Out of 140 GBS isolates 2(1.43%) were resistant to penicillin G, 28(20%) to erythromycin, and 14(10%) to clindamycin and all isolates were susceptible to vancomycin. The HG GBS demonstrated a higher sensitivity compared to enrichment culture. Therefore, the assay could readily be used to screen women who are in labour for GBS rectovaginal colonization to guide IAP.