Molecular epidemiology of antimicrobial resistance and virulence of carbapenem-resistant Klebsiella pneumoniae in South China

OBJECTIVE: Carbapenem-resistant Klebsiella pneumoniae (CRKP) has become a worldwide public health concern due to its high morbidity and mortality rate. A retrospective study was conducted to explore the molecular epidemiology of antimicrobial resistance and virulence of CRKP in South China. METHODS: 108 CRKP isolates were collected from multiple hospitals in South China. The characteristics of the CRKP strains, including antimicrobial resistance genes, mutations and virulence factors, were analyzed using whole-genome sequencing and the software Kleborate. A phylogenetic tree was constructed to illustrate evolutionary diversification. RESULTS: The main Sequence Type (ST) type, capsular serotype, and LPS serotype among CRKP isolates in South China were ST11, KL47, and OL101, respectively. KPC-2 was the most prevalent carbapenemase type. Notably, KPC-12, a recently identified and rarely reported variant of KPC-2, was discovered in four CRKP strains. All ST11 CRKP isolates harbored porin and efflux pump regulator mutations of AcrR-43%, OmpK35-17%, and OmpK36GD as well as fluoroquinolone mutations of GyrA-83I, GyrA-87G, and ParC-80I. All CRKP strains exhibited complex multi-drug resistance (MDR) phenotypes. The most common types of aerobactin (iuc) and yersiniabactin (ybt) were iuc1 and ybt9 ICEKp3, respectively. There were 17 hvCRKP (hypervirulent carbapenem-resistant Klebsiella pneumoniae) strains found in our study, which were mainly ST11-KL64 and ST413-1LV-KL112, harboring t...