Epidemiological characteristics, genotypes, genetic relationships and macrolide resistance of 31 Bor-detella pertussis strains isolated from infants and young children in Shenzhen / 中华微生物学和免疫学杂志

ABSTRACT

Objective To understand the epidemiological characteristics, genomic variations and macrolide resistance of Bordetella pertussis ( B. pertussis) strains circulating in Shenzhen with clinical data analysis, genotype profiling, phylogenetic analysis and antimicrobial susceptibility test. Methods Clinical data of patients with pertussis in Shenzhen Children's Hospital were collected from the electronic medical re-cord system. Genome sequences of 31 B. pertussis isolates were analyzed with next-generation sequencing and de novo assembled. Multilocus sequence typing (MLST) was performed to identify their sequences types. Sequence alignment by BLASTn was used to identify virulence genotypes and mutations in 23S rRNA gene. A phylogenetic tree was constructed to analyze the relationships among them. E-test was used to identify ma-crolide resistance. Results All of the 31 B. pertussis strains were identified as sequence type-2 (ST-2) by MLST with diverse virulence genotypes. Two were prn-deficient strains. Based on the phylogenetic tree, all of the isolates were distant from vaccine strains. Nineteen isolates were resistant to erythromycin with A2047G mutation in 23S rRNA. Conclusions The virulence genotypes of B. pertussis strains in Shenzhen were diverse with increasing non-vaccine genotypes. Macrolide-resistant strains were prevalent. This study might provide reference for improving the prevention, management and vaccination strategy of pertussis.