Escherichia coli is found in the human gut, and is the common pathogen causing urinary tract infections (Wagenlehner et al., 2008; De Francesco et al., 2007; Kashef et al., 2010). Antimicrobial resistance in E. coli has been reported worldwide and the increasing rates of resistance among E. coli are a growing concern in both developed and developing countries (Bell et al., 2002; El Kholy et al., 2003). Antimicrobial resistance makes infections complicated to be treated. Generally, almost 95 % cases with severe symptoms are treated without bacteriological investigation (Dromigny et al., 2005). Occurrence and susceptibility profiles of E. coli show substantial geographic variations as well as significant differences in various populations and environments (Erb et al., 2007). In Pakistan, a number of studies have been done on the prevalence of E.coli and its antimicrobial susceptibility patterns . The aim of this study was to determine the proportions of E.coli, and its antimicrobial susceptibility patterns for efficient management of urinary tract infections.
Material and methods
In this study, E.coli isolates were collected from public and private hospitals and healthcare centers from June 2009 to March 2010. Only one sample was obtained from each patient and included in the study. Clean catch midstream urine specimens were collected in sterilized bottles and submitted to clinical microbiology laboratory. The samples received were inoculated onto Blood agar and McConkey agar, and then incubated in aerobic atmosphere at 37ᵒC for 24 hours. E.coli isolates were confirmed by biochemical tests. The plates yielding growth as per Kass counts (single specie count more than 105 organisms/ml) were processed further (Kass, 1956).
Antimicrobial susceptibility testing
Antimicrobial susceptibility testing was performed by the modified Kirby Bauer disc diffusion method on Muller-Hinton agar (Oxoid, England) as described by the Clinical Laboratory Standard Institute (CLSI) (CLSI, 2006).