Objective: To analyse the prevalence of serotypes, antibiotic resistance, and virulence genes of Group B Streptococcus (GBS) strains isolated from pregnant women at 35-37 weeks of gestation in Ho Chi Minh City, Vietnam, from January 2022 to January 2023. Methods: GBS strains were isolated through selective culture methods and confirmed by PCR. Serotyping, virulence gene detection, and antibiotic susceptibility testing were performed using PCR, gel electrophoresis techniques and Kirby-Bauer test. Results: Totally, 61 GBS isolated from 300 participants have been identified including seven GBS serotypes (Ia, I b, II, III, IV, V, and VI). Serotypes VII, VIII, and IX were not detected in the study population. Antibiotic resistance patterns varied: 13.1% of isolates were fully susceptible, while the majority showed multi-drug resistance, with 34.4% resistant to three antibiotics. Serotype I a demonstrated high susceptibility (35.7%), while serotype III showed extensive resistance, with 87.5% being resistant to at least three antibiotics. All strains are susceptible to vancomycin and β-lactams susceptibility also remained high, but resistance to clindamycin, erythromycin, and tetracycline was high (>65%). The virulence genes scpB, cylB, fbsB , and cfb were highly prevalent (90%-100%), indicating their potential for vaccine and diagnostic development. Conclusions: Our findings provide valuable insights into GBS serotypes, resistance, and virulence factors, contributing to community monitoring, preventive measures, diagnostics, and vaccine development. However, the limited sample size necessitates further research.
Nguyen-Thi et al. (Thu,) studied this question.