Serotype Distribution, Virulence, and Antibiotic Resistance Genomic Characterization of Group B Streptococcus - China, 1998-2024.

INTRODUCTION

, or group B Streptococcus (GBS), can cause severe infections in humans, yet comprehensive genomic characterization from China remains limited. This study presents an extensive genomic analysis of GBS isolates collected in China from 1998 to 2024.

METHODS

GBS genomes were obtained from public databases and through de novo sequencing. Serotype confirmation was conducted via pan-genomic analysis, phylogenetic relationships were established using maximum-likelihood methodology, and virulence and antibiotic resistance genes were identified through the Virulence Factor Database and Comprehensive Antibiotic Resistance Database. Statistical analyses were performed using SPSS 26.0, primarily employing Fisher's exact tests.

RESULTS

Analysis of 747 GBS genomes revealed eight serotypes (Ia, Ib, II, III, IV, V, VI, VII) and nontypeable strains. Serotypes III, Ib, Ia, V, and II constituted 96.65% of all isolates. GBS prevalence remained low from 1998-2011 but increased substantially after 2012. Geographic distribution demonstrated significant regional heterogeneity. Phylogenetic analysis categorized the 747 genomes into five distinct lineages, with lineage 5 being predominant. Six virulence factor categories encompassing 56 virulence-associated genes were identified, with 33 genes present in nearly all genomes. Twenty-seven antibiotic resistance genes spanning nine drug classes were detected, particularly those conferring resistance to peptides and macrolide antibiotics, indicating widespread antimicrobial resistance mechanisms in GBS.

CONCLUSIONS

GBS infections in China exhibit serotype distributions similar to global patterns but with notable regional variations. This comprehensive genomic characterization provides critical insights for developing targeted prevention strategies and treatment approaches for GBS infections in China.