Genomic insights into evolution of extensive drug resistance in Stenotrophomonas maltophilia complex.

We report first complete genomic investigation of extensive drug resistance (XDR) in a nosocomial Stenotrophomonas maltophilia complex strain that is resistant to mainstream drugs (trimethoprim/sulfamethoxazole and levofloxacin). Comprehensive genomic investigation revealed its exclusive fourteen dynamic regions and highly enriched resistome comprising of two sulfonamide resistance genes on two diverse super-integrons of chromosomal origin. In addition, both these integrons harbour array of antibiotic resistance and commonly used disinfectant's resistance genes linked to ISCR elements. Isolation of a novel XDR strain from Indian tertiary care unit belonging to novel ST with diverse array of resistance genes on ISCR linked super-integrons indicates extent and nature of selection pressure in hospitals. Since, repetitive elements have major role in their spread and due to limitations of draft genomes, there is an urgent need to employ complete genome-based investigation for tracking the emergence of XDR at global level and designing strategies of antimicrobial stewardship and disinfection. IMPORTANCE: Hospital settings in India have one of the highest usages of antimicrobials and a heavy patient load. We hereby report a novel clinical isolate of S. maltophilia complex with two super-integrons that harbour array of antimicrobial resistance genes along with biocide and heavy metal resistance genes. Further, the presence of ISCR type of transposable elements on both the integrons indicates their propensity to transfer resistome while their chromosomal origin suggests possibilities for further genomic/phenotypic complexities according to selection pressure. Such complex mobile cassettes in a novel strain is a potential threat to global health care. Hence, to understand the evolution of opportunistic nosocomial pathogen, there is an urgent need to employ cost-effective long read technologies to keep vigilance on novel and XDR pathogens in populous countries. There is also need for surveillance of the usage of disinfectants and other antimicrobials for environmental hygiene and linked/rapid co-evolution of XDR in nosocomial pathogens. Repositories: Complete genome sequence of Stenotrophomonas maltophilia SM866: CP031058.