Occurrence of blaOXA-116 Carbapenemase in Escherichia coli ST2519 of Clinical Origin: A Report from Northeast India.

Carbapenem-resistant Escherichia coli pose a significant threat to global public health due to the dearth of available treatment options, resulting in infections with high mortality and morbidity. The study aimed to investigate the mechanism of carbapenem resistance in a carbapenem non-susceptible E. coli isolate recovered from an urinary tract infection patient admitted to a tertiary referral hospital, through whole-genome sequencing using Illumina NovaSeq 6000 platform. Carbapenemase production followed by antibiotic susceptibility testing were performed following Clinical Laboratory Standard Institute guidelines. Polymerase chain reaction targeting carbapenemase genes was performed followed by an investigation of horizontal transferability. The Center for Genomic Epidemiology database was used to analyze the sequenced data. ST2519 E. coli BJD_EC1808 with a genome size of 5.8 Mb harbored Col440I plasmid and a chromosomally located blaOXA-116 gene with an IS18 element upstream, along with multiple antibiotic resistance genes conferring clinical resistance toward beta-lactams, aminoglycosides, amphenicols, sulfonamides, tetracyclines, trimethoprim, rifampin, macrolide, and streptogramin antibiotics and antiseptics. E. coli ST2519 harboring blaOXA-116 associated with a mobile genetic element exhibiting carbapenem resistance is a public health threat due to its limiting effect on the therapeutic usage of carbapenem and their dissemination into carbapenem non-susceptible phenotypes will contribute to carbapenem resistance burden and, therefore, warrants urgent monitoring and clinical intervention.