Prevalence and Susceptibility Patterns of Clinical Isolates of Escherichia coli to Various Antimicrobials in A Clinical Microbiology Laboratory in South-South Nigeria

The purpose of this study is to determine the prevalence of Escherichia coli as an aetiologic agent in bacterial infections and its antimicrobial susceptibility patterns to ciprofloxacin, ofloxacin, norfloxacin, perfloxacin, gentamycin and cotrimoxazole as a guide for empiric therapy. A retrospective study was carried out using a clinical microbiology laboratory in Nigeria. Data retrieved include number of E. coli isolates, sources of the isolates and their antimicrobial susceptibility to various fluoroquinolones, gentamycin and cotrimoxazole between 2005 and 2009. Statistical analysis was carried out using SPSS version 14, Chicago IL. Out of a total of 906 bacterial isolates, E. coli accounted for 23 % (211) of the isolates. Thirty-eight percent (38.39 %) was isolated from urine samples, 27.96 % from high vaginal swab samples, 24.17 % from stool samples, 0.95% from urethra swabs, 1.9% from wound swabs and 6.6% from semen samples. There was poor level of susceptibility to norfloxacin (2.2%) and cotrimoxazole (23.7%), susceptibility to ofloxacin, ciprofloxacin and pefloxacin were 51.1%, 54.7% and 52.5% respectively, that of gentamycin was 51.8%. The trends across the years showed a significant increase in susceptibility to ciprofloxacin, pefloxacin and ofloxacin in 2007 after which it started reducing, while norfloxacin’s susceptibility was low across the five years with maximum susceptibility at 9.1% in 2006. There was an increase in susceptibility to gentamycin as the susceptibility levels of the fluoroquinolones were reducing. There should be continuous surveillance of antimicrobial susceptibility patterns and empiric treatment with fluoroquinolones discouraged, especially for non urinary tract infections. KEYWORDS: Antimicrobial susceptibility, Nigeria, Escherichia coli, fluoroquinolones, gentamycin