Objectives: Group B Streptococcus (GBS) is an important pathogen for invasive diseases in not only neonates and pregnant women but also elderly patients with underlying diseases. This study was aimed to delineate the molecular genotype distribution and virulence factors of invasive GBS isolates from north and central Taiwan, from 2008-2015.
Methods: A total of 171 clinical GBS bloodstream isolates from Show Chwan Memorial Hospital, Chang Bing Show Chwan Memorial Hospital, and Taipei Veterans General Hospital from 2008-2015 were determined for molecular serotyping, multi-locus sequence typing (MLST), distribution of 7 virulence genes and susceptibilities to 8 non-beta-lactam antimicrobial agents.
Results: In the present study, the three leading GBS genotypes in order were Type III (18.1%), Type II (17%) and Type Ib. For MLST, ST1/genotype VI (26.7%) was predominated, followed by ST12/Genotype Ib (13.3%) and ST17/genotype III (7.7%). In terms of virulence genes, rib and bac genes were carried by genotype III (80.6%) and genotype Ib (96.2%), respectively, but were rarely detected amongst other genotypes. ST17 was exclusively found in genotype III with 100% harboring of the hvgA gene. All GBS isolates remained 100% susceptible to penicillin and ampicillin but high resistances to erythromycin and clindamycin were seen, particularly in genotype Ib.
Conclusions: Genotype III and ST 1 GBS strains were the most prevailing types in this study. Virulence gene distributions characterized certain genotypes, particularly in the ST17 strain. Molecular epidemiological analysis of GBS presents a picture of evolution over time and offers fundamental information for GBS vaccine development.