Abstract

Emerging antibiotic resistance due to extended spectrum β-lactamase (ESBL) production limited the use of β-lactam antibiotics against Escherichia coli andKlebsiella pneumoniae. This observational study was conducted at the Microbiologydepartment of the Children’s Hospital, Lahore Pakistan, from June, 2009 to November, 2010 to determine the frequency and antimicrobial resistance of ESBL producing E. coli and K. pneumoniae. A total of 13638 urine samples were processed for culture and antimicrobial sensitivity testing. E. coli and K. pneumoniaewere identified using API 20E. A double disk synergy test (DDST) was performed to determine ESBL production. ESBL production was detected in 312 (57.4%) E. coliand 386 (71.7%) K. pneumoniae. A multidrug resistance pattern was seen in ESBL producing E. coli and Klebsiella pneumoniae. ESBL producing E. coli showed maximum resistance to cefotaxime (100%), ceftazidime (99.4%) and cefuroxime (93.3%) while minimum resistance was seen with meropenem (1.3%), piperacillin/tazobactam (10.3%) and nitrofurantoin (27.6%). ESBL producing K. pneumoniae showed maximum resistance to ceftazidime (100%), cefotaxime (98.7%) and cefuroxime (98.1%) while minimum resistance was seen withmeropenem (3.6%), piperacillin/tazobactam (17.6%), and nitrofurantoin (28.5%). In ESBL producing bacteria, high prevalence of antibacterial resistance of non-β-lactam antibiotics is a serious matter of concern. Monitoring of ESBL production and antimicrobial susceptibility testing are necessary to avoid treatment failure in patients with urinary tract infection (UTI). 

Key words: Extended spectrum, beta-lactamases, urinary tract infections,Escherichia coli, Klebsiella pneumoniae.