Study of Drug Resistance in Enterobacteriaceae Isolates

Background & objectives: Members of the family enterobacteriaceae comprise the most common gram-negative isolates in microbiology laboratories. Amongst these members, multiple antibiotic-resistant isolates including those producing extended spectrum β-lactamases (ESBL) and AmpC β-lactamases (AmpC) have increased steadily. Further, metallo-β-lactamase (MBL) producing strains are also recently detected. Methods: Three hundred enterobacteriaceae isolates were subjected to antibiotic susceptibility testing. ESBL production was tested by CLSI phenotypic confirmatory test and double disk synergy test using amoxiclavcefotaxime and piperacillin-tazobactam cefepime. AmpC was tested by cefoxitin-cefotaxime disk antagonism test. MBL was tested by combined disk test. Results: Amongst 300 enterobacteriaceae isolates, 111 were ESBL, 12 AmpC and 30 MBL producers. K. pneumoniae showed maximum drug resistance and β-lactamase production. Interpretation & conclusion: High drug resistance and β-lactamase production is observed in enterobacteriaceae isolates. It is necessary to keep vigilance for the resistant isolates. [Agrawal G et al NJIRM 2013; 4(2) : 113-117]