Prevalence and multidrug resistance of Escherichia coli from community-acquired infections in Lagos, Nigeria.

INTRODUCTION: The emergence of multidrug resistance (MDR; resistance to ≥ 2 more antimicrobials) in Escherichia coli is of concern due to complications encountered in treatment.

METHODOLOGY: In this study, prevalence, antimicrobial resistance, and genetic characteristics of MDR community isolates of E. coli from Lagos, Nigeria were determined. Urine and stool samples were obtained from outpatients attending Lagos State hospitals and from animal handlers in abattoirs, poultries, and open markets, from December 2012 to July 2013.

RESULTS: Approximately 50% of urine (200/394) and 88% of stool samples (120/136) were positive for E. coli. Based upon β-lactamase production, a subset of those isolates was selected for further study. Of the 22 antimicrobials tested, E. coli exhibited resistance to all antimicrobials except amikacin and piperacillin/tazobactam. The highest levels of resistance were to tetracycline (182/247; 73.7%), trimethoprim/sulfamethoxazole (152/247; 61.5%), and ampicillin (147/247; 59.1%). Resistance to the cephalosporins ranged from 1.6%-15% including the third- and fourth-generation cephalosporins, cefpodoxime (20/247; 8.1%) and cefepime (4/247; 1.6%), respectively. MDR was observed in 69.6% (172/247) of the isolates. Forty-eight E. coli resistant to at least five antimicrobials were selected for further analysis using pulsed-field gel electrophoresis; seven distinct clusters were observed among the diverse patterns. Of the 48 MDR E. coli, 30 different sequence types (ST) were detected using multilocus sequence typing, including four ST131.

CONCLUSIONS: This study demonstrated circulating MDR E. coli in the Nigerian community. Monitoring of antimicrobial resistance in developing countries is necessary to optimize empiric treatment and the prudent use of antimicrobials.