Prevalence of bla CTX M Extended Spectrum Beta Lactamase Gene in Enterobacteriaceae from Critical Care Patients

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.