Occurrence of blaOXA-48 type carbapenemase in Escherichia coli with coexisting resistance determinants: A report from India

Abstract

The Ambler class D β-lactamase, OXA-48 has emerged as one of the most frequently reported and clinically significant carbapenemase. The study aims to investigate the carriage of blaOXA-48 within Escherichia coli of clinical origin along with their resistance profile, carriers and associated genes from a tertiary referral hospital of Northeast India. From January 2019 through December 2019, 179 Escherichia coli isolates with reduced susceptibility to carbapenem were collected and screened for the presence of blaOXA-48 gene via PCR assay. OXA-48 positive isolates were further checked for coexistence of different carbapenemases and ESBLs genes followed by their horizontal transferability, plasmid incompatibility by PBRT, phylogroup analysis and strain typing via ERIC PCR. PCR assay result revealed that 20.67% (n = 37) multidrug resistant Escherichia coli isolates were harbouring the class D carbapenemase gene blaOXA-48. 43.24% (n = 16) of the blaOXA-48 positive isolates were co-harbouring other resistance genes namely blaNDM (n = 11), blaOXA-23 (n = 2), blaOXA-58 (n = 1), blaTEM (n = 1) and blaCTX-M-15 (n = 1). The study identified diverse conjugatively transferable Inc type plasmids were carrying this gene within 11 different haplotypes of Escherichia coli. In addition to Inc L/M plasmid, the study identified four Inc types (FREPB, A/C, K/B and FIB) with the carriage of blaOXA-48 among the phylogenetic groups A, B1 and B2 of Escherichia coli. Genetic analysis of blaOXA-48 showed the association with two different insertion sequences in the upstream region. The need of the hour is monitoring of this plasmid mediated gene along with its potential carriers to check their further dissemination so that they don't act as future source to spread carbapenem resistance in this region.