Genomic rearrangements of mobile genetic elements associated with carbapenem resistance of Acinetobacter baumannii

Abstract

AbstractWith the excessive genome plasticity, Acinetobacter baumannii has the capability to acquire and disseminate antimicrobial resistance genes that are often associated with mobile genetic elements (MGE). Analyzing the genetic environment of resistance genes often provides valuable information on the origin, emergence, evolution and spread of resistance. Thus, we characterized the genomic features of some clinical isolates of carbapenem-resistant A. baumannii to understand the role of diverse MGE and their genetic context that are responsible for the dissemination of carbapenem resistance genes. For this, a total of 17 clinical isolates of A. baumannii obtained from multiple hospitals in India between the years 2018 and 2019 were analysed. Antimicrobial resistance determinants, genetic context of resistance genes and molecular epidemiology were studied using whole genome sequencing. A high prevalence of blaOXA-23 was observed followed by the presence of dual carbapenemase, blaOXA-23 and blaNDM. Three novel Oxford sequence types were identified. Majority of the isolates belonged to dominant clone, IC2 followed by less prevalent clones such as IC7 and IC8. Complex diverse AbaR4 like and AbGRI-like islands belonging to IC2 lineage were identified. To the best of our knowledge, this is the first study that provides a comprehensive profiling of resistance islands along with the MGE, acquired antimicrobial resistance genes and the distribution of clonal lineages of carbapenem resistant A. baumannii from India.