Antimicrobial resistance in E. Coli associated with urinary tract infection in the West of Ireland

Background: Knowledge of antimicrobial resistance patterns in E. coli, the predominant pathogen associated with urinary tract infection (UTI) is important as a guide in selecting empirical antimicrobial therapy. Aims: To describe the antimicrobial susceptibility of E. coli associated with UTI in a region in the West of Ireland. Methods: A collection of 934 E. coli isolates associated with UTI were tested for susceptibility to a panel of antimicrobial agents by the disc diffusion method of the National Committee for Clinical Laboratory Standards. Results: More than 50% of E. coli were resistant to ampicillin, more than 40% resistant to sulphonamide and more than 30% resistant to trimethoprim. From 7.9% (community) to 12.5% (hospital) are resistant to co-amoxiclav with approximately 20% of isolates of intermediate susceptibility. In general practice most E. coli remain susceptible to nitrofurantoin (96.7%), nalidixic acid (93.9%) and ciprofloxacin (94.7%). For all agents rates of resistance were higher in hospital as compared with general practice isolates. Three isolates with the phenotype of Extended Spectrum Beta-lactamase (ESBL) resistance were detected. Conclusions: Ampicillin/amoxicillin are not suitable for empiric therapy of UTI in general practice or hospital patients in this region. There is doubt as to the role of trimethorpim or co-trimoxazole for empiric therapy of UTI. Nitrofurantoin, nalidixic acid and ciprofloxacin are active against the great majority of UTI associated E. coli.