Extended spectrum -lactamases in urinary isolates of Escherichia coli and Klebsiella pneumoniae - prevalence and susceptibility pattern in a tertiary care hospital.

A total of 411 urinary isolates (353 Escherichia coli and 58 Klebsiella pneumoniae) were studied for extended spectrum -lactamase (ESBL) production by double disk approximation test and NCCLS confirmatory test. ESBL production was found to be 41% in E. coli and 40% in K. pneumoniae. Fourteen percent and 12% of ESBL producers showed false susceptibility to ceftazidime and cefotaxime in routine susceptibility testing. The susceptibility of ESBL producers to imipenem, nitrofurantoin and amikacin was found to be 100%, 89% and 86% respectively. A high degree of associated resistance to gentamicin, co-trimoxazole and quinolones was found in ESBL producers. Majority of ESBL producers was detected among patients admitted in medical ICU and surgery ward.