FREQUENCY AND DISTRIBUTION OF TEM AND CTX-M GENES IN ESBL PRODUCING ENTEROBACTER CLOACAE

Abstract

The Enterobacteriaceae family of bacteria includes naturally occurring facultative anaerobic gram-negative bacteria. These bacteria are saprophytic in nature and reside in soil and sewage. Most importantly, these bacteria also part of the symbiotic gut microbial community residing in human gastrointestinal system. In the last several decades, Enterobacter has become clinically significant, as it has emerged as a leading nosocomial infection causing agent in patients of critical care units. The problem has further aggravated by the accumulating evidence of resistance of E. cloacae to routinely prescribed antibiotics, specifically those caused extended spectrum beta-lactamases. Keeping this in view, it’s critical to keep track of antibiotic resistance and the frequency of causative genes in a population on a regular basis. As a result, the current study focused on determining the frequency of E. cloacae TEM and CTX-M genes isolated from clinical samples. A total of 150 Clinical samples (30 urine, 30 pus, 30 sputum, 30 bloods, and 30 wounds) were collected from patients admitted or visiting the Khyber Teaching Hospital in Peshawar to isolate ESBL producing E. cloacae. The antibiotic resistance analysis of positive samples revealed highest resistance to Aztreonam (92%) followed by Ceftazidime (82%), Ciprofloxacin (56%), Piperacillin (50%), Imipenem (32%), Gentamycin and Cefepime (30%), Amikacin (28%), Meropenem (22%), and Ertapenem (22%). Colistin, on the other hand, showed the least amount of resistance (2%). ESBL genes frequency investigation using Polymerase Chain Reaction (PCR) revealed that the majority of resistant isolates (47%) contained the TEM gene, while 38% had the CTX-M gene, and 15% were negative for both.

It is concluded that ESBL based antiobiotic resistance is at rise (1/3 of the samples resulted positive) which is mainly (85%) caused by presence of either TEM or CTX-M genes.  The medical practitioner should consider this alarming rise of resistance while prescribing the antibiotics.