Incidence of blaNDM-1 gene in Escherichia coli isolates at a tertiary care referral hospital in Northeast India

Purpose: Increasing reports on New Delhi metallo-beta-lactamase-1 (NDM-1) producing Escherichia coli constitute a serious threat to global health since it is found to be highly resistant to most of the currently available antibiotics including carbapenems. This study has been performed to find out the incidence bla(NDM-1) in E. coli isolates recovered from the various clinical samples at a tertiary care referral hospital in Northeast India. Materials and Methods: A total of 270 non-duplicated E. coli isolates were recovered from the various clinical samples at a tertiary care referral hospital in Northeast India. All isolates with reduced susceptibility to meropenem or ertapenem (diameter of zones of inhibition, <= 21 mm) were further phenotypically confirmed for carbapenemase production by modified Hodge test. All screened isolates were also subjected to the polymerase chain reaction detection of bla(NDM-1) gene and additional bla genes coding for transmission electron microscopy, SHV, CTX-M, and AmpC. Results: Out of 270 E. coli isolates, 14 were screened for carbapenemase production on the basis of their reduced susceptibility to meropenem or ertapenem. All screened isolates were found to be positive for bla(NDM-1). Each of the bla(NDM-1) possessing isolate was also positive for two or more additional bla genes, such as bla(TEM), bla(CTX-M) and bla(AmpC). Phylogenetic analysis showed very less variation in bla(NDM-1) gene with respect to bla(NDM-1) possessing E. coli isolates from other parts of India and abroad. Conclusions: Our findings highlight the incidence of bla(NDM-1) in E. coli isolates with a reduced susceptibility to meropenem or ertapenem.