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Context:Critical care units provide a favourable environment for the antimicrobial resistant organisms to disseminate. There is recent increase in number of extended spectrum beta lactamase (ESBL) producers because of the emergence of CTX M Beta lactamases produced by Enterobacteriaceae. They colonize the intestinal flora and spread with greater intensity in the community and hospital. Usage of Carbapenems becomes mandatory as the ESBL inhibitor combination antibiotics (Amoxicillin/Clavulanate) are not effective especially against CTX M ESBLs.Aim:The aim of this study is to detect ESBL producing bla CTX M gene in Enterobacteriaceae from infections in Critical care patients and to stress on the intensity of the problem and to make interventions to curb the emergence and dissemination of CTX M ESBLs.Materials and Methods:A total of 118 Enterobacteriaceae isolates from Critical care unit patients were recovered from a variety of clinical specimens. Antimicrobial susceptibility test was done and isolates with resistance or with reduced susceptibility to any of the third generation Cephalosporins were selected for the study. Phenotypic confirmation of ESBL production was done by Double Disc Synergy Test and confirmed by minimum inhibitory concentration. Multiplex polymerase chain reaction was performed to screen the four groups of CTX-M ESBLs.Results:Among the 118 isolates of Enterobacteriaceae 54 isolates were positive for CTX-M group I ESBL which constitutes 45.7 %.Conclusions:Early detection of CTX M producing Enterobacteriaceae by continuous surveillance and thereby reducing their spread and restricted use of third generation Cephalosporins (3GC) antibiotics could be the possible routes to prevent the emergence and spread of CTX M ESBL producing organisms.

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Production of Extended Spectrum β-Lactamase is an important mechanism of antimicrobial resistance exhibited by Enterobacteriaceae. There are many types of ESBLs among which CTX M is a latest emerged one which carries the bla CTX M gene. CTX M lactamase producing Enterobacteriaceae are present in the intestinal flora without harming the host causing infection in extra intestinal sites. Transferring the gene through plasmids is responsible for the dissemination of antimicrobial resistant strains in the community. This study is designed to detect bla CTX-M gene in Escherichia coli isolates. Method: A total of 532 Escherichia coli isolates were screened for susceptibility testing. Isolates with decreased resistance to third generation Cephalosporins (3GC) were subjected to double disk synergy test for phenotypic confirmation of ESBL in which 178 were positive. Multiplex PCR was done for these 178 isolates to detect the four groups I, II, III & IV of CTX M. Results: Multiplex PCR yielded the products with predicted size for group 1 CTX M in 152 (28.57%) isolates. None of the isolates were positive for other groups of CTX M (Group II, III & IV) Conclusion: The presence of CTX M ESBL producing E. coli cause enormous problems in therapeutic interventions of infections which can be prevented only by continuous surveillance and prudent use of antibiotics.