Increasing reports on New Delhi metallo-β-lactamase-1 (NDM-1) producing Enterobacteriaceae, particularly Escherichia coli and Klebsiella pneumoniae constitute a serious threat to global health. Although, NDM-1 was first reported in 2009 in a Swedish patient previously admitted to an Indian hospital, till the data on the NDM-1 producing Enterobacteriaceae in Indian hospital is limited due to constrained resources. Therefore, the present study was designed to evaluate the incidence of blaNDM-1 gene in E. coli and K. pneumoniae isolates at a tertiary care referral hospital in Northeast India. A total of 412 consecutive, non-duplicate isolates of E. coli (n=221) and K. pneumoniae (n=191) were recovered from various clinical samples. On the basis of their reduced susceptibility to meropenem or ertapenem, 55 (24.88%) E. coli and 52 (27.22%) K. pneumoniae were screened for detection of blaNDM-1 by PCR. All screened isolates were found to be positive for blaNDM-1. Each of the blaNDM-1 possessing isolates of E. coli and K. pneumoniae was also found to be positive for one or more additional bla genes, such as blaTEM, blaSHV, blaCTX-M and blaAmpC. All the blaNDM-1 possessing isolates were “multidrug-resistant” as well as 56.36% E. coli 63.46% of K. pneumoniae isolates with blaNDM-1 were “pandrug- resistant”. In addition, few of the blaNDM-1 positive isolates showed reduced susceptibility to tigecycline and colistin, which extremely limits the treatment options for infections cause by NDM-1-positive isolates.

Arijit Bora has completed his PhD from Department of Biotechnology, Gauhati University, Assam, India in association with Department of Microbiology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, India. He has more than 10 years of academic and laboratory experiences in the field of Medical Microbiology. Presently, he is working as a scientific officer in the Department of Applied Sciences, GUIST, Gauhati University, Assam, India. He has published 09 papers in reputed journals and presented his research works in two international conferences

Background: The aim of this study was to determine the frequency of blaNDM, blaPER, bla VEB, blaIMP and bla- VIM type genes among A. baumannii isolates from hospitalized patients in Milad and Loghman Hakim hospitals, Tehran- Iran from 2012 to 2013.rnMethods: This study was conducted on 108 A. baumannii isolates collected from Milad and Loghman Hakim hospitals in Tehran, Iran. Antibiotic susceptibility tests were performed by Kirby-Bauer disc diffusion and Broth micro dilution methods according to CLSI guidelines. The frequency of MBL (metallo-beta-lactamase) and ESBL (extended spectrum- beta-lactamase) producers were evaluated by CDDT (Combined disk diffusion test). The blaNDM, bla- PER, blaVEB, blaIMP and blaVIM genes were detected by PCR and sequencing methods.rnResults: The resistance of A. baumannii isolates to the tested antibiotics were as follow: 103 (95.4%) to ceftazidime, 108 (100%) to cefotaxime, 105 (95.7%) to cefepime, 99 (91.7%) to imipenem, 99 (91.7%) to meropenem, 87 (80.6%) to amikacin, 105 (97.2%) to piperacillin, 100 (92.6%) to ciprofloxacin, 103 (95.4%) to piperacillin/tazobactam, 44 (40.7%) to gentamicin, 106 (98.1%) to ampicillin/sulbactam, 106 (98.1%) to co-trimoxazole, 87 (80.6%) to tetracycline and 1 (1.8%) to colistin. Using combined disk diffusion test, it was found that out of 108 cefotaxime-non-susceptible A. baumannii strains, 91 (84.2%) were ESBL producers and out of 99 imipenem non-susceptible A. baumannii strains, 86 (86.86%) were MBL producers. The prevalence of blaPER-1 and blaVEB-1 genes among 91 of ESBL-producing A. baumannii isolates were 71 (78.03%) and 36 (39.5%), respectively. The prevalence of IMP-1 and VIM-1 genes among metallobeta- lactamase-producing A. baumannii isolates was 3 of 86 (3.48%) and 15 of 86 (17.44%) respectively and also confirmed for blaOXA-51 gene by PCR. Fortunately, blaNDM gene was not detected in isolates.rnConclusion: The prevalence of ESBLs and MBLs-producing A. baumannii strains is a major concern and highlights the need of infection control measures including prompt identification of beta-lactamase-producing isolates and antibacterial management.rn