Phenotypic and molecular characterization of extended spectrum and#946; lactamase producing Escherichia coli and Klebsiella pneumonia isolates from animal sources

Abstract

Extended-spectrum beta-lactamase producing Enterobacteriaceae has become a newlinemajor threat to both animals and human health globally. The present study was newlineundertaken to isolate and identify ESBL producing Escherichia coli and Klebsiella newlinepneumoniae from various sources, to study their resistant gene profile, to detect insertion newlinesequences, to genogroup the isolates and to compare the efficacy of REP-PCR and PFGE newlineto discriminate ESBL producing E. coli and K. pneumoniae isolates. newlineOut of 385 samples from various sources, 31 (8.05%) were positive for ESBL newlineproducing E. coli. Such isolates could be isolated from 10.05, 8.33, 15.63, 6.67 and 4.35 newlineper cent of cattle milk, curd, chicken, pork and cattle faeces samples, respectively. newlineHowever, no ESBL producing E. coli could be isolated from goat milk, goat faeces and newlinebeef samples. A total of 59 (15.32%) samples were positive for ESBL producing K. newlinepneumoniae, which could be isolated from 14.35, 6.25, 21.43 and 34.78 per cent samples newlineof cattle milk, chicken, beef and cattle faeces, respectively. No ESBL producing K. newlinepneumoniae isolates could, however, be isolated from goat milk and faeces, curd and newlinepork. newlineIn-vitro drug susceptibility assay against 3rd and 4th generation cephalosporins newlineshowed resistance of all the 90 ESBL isolates to at least one antibiotic. In CDT, 93.55% newlineof E. coli and 88.14% K. pneumoniae and in ESBL E test, 96.77% E. coli and 88.14% newlineK. pneumoniae showed positive results. newlineAntibiogram of the ESBL producing E. coli and K. pneumoniae showed newlineresistance of 74.19% and 69.49%, respectively to ceftizoxime, 25.81% and 23.73% to newlineboth co-trimoxazole and tetracycline, 19.35% and 25.42% to ciprofloxacin, 9.68% and newline16.95% to chloramphenicol, 3.23% and 5.08% to pipercillin-tazobactam, and 3.23% and newline3.39% to gentamicin. newlineResistance gene profiling showed blaCTX-M gene to be present in all the 90 newline(100%) ESBL isolates. The blaTEM gene was found in 54.84% and 55.93%, blaSHV newlinegene in 90.32% and 77.97%, Sul 1 gene in 90.32% and 86.44% isolates. The Int1 gene newlinewas detected in 70.97% and 62.71% isolates, while qnrB gene was found in 3.23% and newline10.17% of E. coli and K. pneumoniae isolates, respectively. newlineOut of the insertion sequences under study, ISEcp1 was found to be present in all newlinethe 90 (100%) ESBL producing isolates, followed by IS26 (100% and 90.32%) and newlineISCR1 (80.65% and 45.76%) in E. coli and K. pneumoniae isolates, respectively. All the newline90 ESBL producing isolates were subjected to PCR for detection of CTX-M genogroups. newlineAll the 90 (100%) ESBL producing isolates were found to be positive for group 1 gene. newlineA total of 80.65% and 55.93% E. coli and K. pneumoniae isolates, respectively showed newlinepresence of group 2 genes. The corresponding percentages for group 25 gene were newline27.27% and 67.8%. However, group 9 gene could be detected in 5.08% of K. newlinepneumoniae isolates only. None of the E. coli isolates were found be positive for group newline8 and 9 genes, while no isolate of K. pneumoniae was found to be positive for group 8 newlinegene. newlineThe two molecular typing methods, REP-PCR and PFGE were found to show newlinesimilar discriminatory power and could distinctly differentiate the ESBL producing E. newlinecoli and K. pneumoniae isolates. As both the methods were found equally competent, newlineREP-PCR may be recommended as the preferred method of typing for epidemiological newlineinvestigations owing to its advantages over PFGE in terms of rapidity, simplicity and newlineease of performance. newline