Phenotypic expression and prevalence of multi drug resistant extended spectrum beta-lactamase producing Escherichia coli and Klebsiella pneumoniae in Karachi, Pakistan.

The aim of the present study was to evaluate the prevalence rate of ESBL producing Gram negative isolates of E. coli, K. pneumoniae and P. mirabilis, to determine the association of various factors with ESBL production and therapeutic options for the treatment. Total 352 isolates were subjected for identification of ESBL by double disc synergy test. Antimicrobial susceptibility was performed using CLSI guidelines and statistical association between ESBL/Non ESBL producers were determined by chi square at significant level of 0.05. A total of 96 isolates were ESBL positive (27%), females were 67% whereas males were 33%. E. coli was most prevalent pathogen (82%) followed by Klebsiella pneumoniae (17%). Furthermore 75% of ESBL associated infections were urinary tract infections. 95% of ESBL producing isolates were multidrug resistant and tazobactam/piperacillin combination and imipenem are good choices with 100% and 97% susceptibility respectively. E coli (OR 2.83, 95% CI 1.585-5.072, RR 2.22, p 0.0004) and K. pneumoniae (OR 0.52, 95% CI 0.285-0.952, RR 0.609, p 0.032) were significantly associated with ESBL production. The spread of ESBL producing multidrug resistant E. coli and K. pneumoniae has increased and proper screening for ESBL identification is needed because of limited therapeutic antibiotic choices.