Report on carbapenemase-producing rare sequence types of Escherichia coli and Enterobacter hormaechei

Abstract

Introduction and Aim: Carbapenem Resistant Enterobacteriaceae (CRE) have emerged at an alarming rate. Multi locus sequence typing (MLST) is an important parameter for identifying drug resistant organisms. The present study was carried out for elucidating the mechanisms of CRE and MLSTs associated with CRE. Materials and Methods: CRE (n=14) were obtained from various clinical samples and subjected to Rapidec Carba NP (CNP) test and multiplex polymerase chain reaction (M-PCR) and five isolates proceeded for whole genome sequencing (WGS). ?-lactamase (bla) genes were analysed using Resfinder and CARD tool. Bioinformatics tools: mlplasmids, plasmid finder, mobile element finder, and Center for Genomic Epidemiology (CGE) toolbox were used. Results: All isolates (n=14) were positive for CNP and bla genes using M-PCR. Isolates (J21, J22, J23, J27) were identified as Escherichia coli while (J34) was Enterobacter hormaechei. MLST showed E. coli isolates (J21& J22) as ST648; E. coli (J23) was ST940; E. coli (J27) was ST 2851, and E. hormaechei (J34) was closest to ST1325. Genes blaTEM, blaNDM & blaampC were found to be present in all isolates; blaCTX-M was present in all E. coli isolates but not in E. hormaechei. blaOXA was present in E. coli (J23) and in E. hormaechei (J34); while ESBL blaSFO-1 in E. hormaechei (J34). Conclusion: ESBLs (blaTEM & blaCTXM) and metallo beta-lactamase -MBL (blaNDM) cause carbapenem resistance in rare sequence types of E. coli while; ESBL (blaSFO-1) and MBL (blaNDM) cause carbapenem resistance in E. hormaechei.