Molecular characterization of carbapenem-resistant and virulent plasmids in from patients with bloodstream infections in China.

Bloodstream infections (BSIs) caused by carbapenem-resistant (CRKP) are potentially life-threatening and an urgent threat to public health. The present study aims to clarify the characteristics of carbapenemase-encoding and virulent plasmids, and their interactions with the host bacterium. A total of 425 isolates were collected from the blood of BSI patients from nine Chinese hospitals, between 2005 and 2019. Integrated epidemiological and genomic data showed that ST11 and ST307 isolates were associated with nosocomial outbreak and transmission. Comparative analysis of 147 genomes and 39 completely assembled chromosomes revealed extensive interruption of by IS in all carbapenemase-2 (KPC-2)-producing ST11 isolates, leading to activation of the AcrAB-Tolc multidrug efflux pump and a subsequent reduction in susceptibility to the last-resort antibiotic tigecycline and six other antibiotics. We described 29 KPC-2 plasmids showing diverse structures, two virulence plasmids in two KPC-2-producing , and two novel multidrug-resistant (MDR)-virulent plasmids. This study revealed a multifactorial impact of KPC-2 plasmid on , which may be associated with nosocomial dissemination of MDR isolates.