Antimicrobial resistance patterns in outpatient urinary tract infections - the constant need to revise prescribing habits

Abstract

Background. There is a global emergence of resistance against commonly prescribed antibiotics. Empirical antibiotic prescribing should be guided by local antimicrobial susceptibility patterns.
Aim. To identify organisms and determine antibiotic susceptibility in urinary tract infections (UTIs) at 3 Military Hospital, Bloemfontein.
Methods. All urine samples collected during 2008 were analysed. The first positive urine culture per patient collected from the casualty, gynaecology, internal medicine and surgical outpatient departments were included. Only adult patients (>12 years old) were included. Prior use of antibiotics and underlying conditions were determined from electronic and paper-based patient and pharmacy records.
Results. Positive cultures (N=65) were divided into uncomplicated (N=28) and complicated (N=37) UTIs. Escherichia coli (E. coli) was the most common uropathogen in uncomplicated (75%) and complicated (59%) UTIs. In uncomplicated UTIs, trimethoprim-sulfamethoxazole (TMP-SMX) (54%) and amoxicillin (46%) had the highest rates of resistance. Nitrofurantoin and ciprofloxacin had sensitivity rates of 89%. Co-amoxiclav was most commonly prescribed (36%). In complicated UTIs, TMP-SMX (68%) and amoxicillin (65%) had the highest resistance rates, followed by ciprofloxacin (41%). Nitrofurantoin had a sensitivity rate of 73%. Ciprofloxacin was prescribed most often (35%). All E. coli UTI isolates were sensitive to nitrofurantoin.
Conclusion. E. coli remains the most common uropathogen. TMP-SMX and amoxicillin are of no value in this population with UTIs. Uncomplicated UTIs can be treated effectively with nitrofurantoin; this will lead to cost savings and sparing quinolones as a class of antibiotics known to induce resistance. In this setting, ciprofloxacin should not be used empirically for complicated UTIs.