Appropriateness of trimethoprim as empiric treatment for cystitis in 15-55 year-old women: an audit.

AIM: To assess whether trimethoprim remains an appropriate empiric treatment for uncomplicated cystitis in women 15-55 years old.

METHODS

General practitioners in Auckland, Nelson-Marlborough, Otago and Southland were invited to participate in this audit of current practice. Participating general practitioners were asked to submit urine to the laboratory for microscopy and culture from any woman aged 15-55 years presenting with uncomplicated cystitis. Urine samples submitted as part of the audit were identified by a "copy to" code. Data on laboratory results were extracted from the laboratory information system.

RESULTS

Data were collected from June 2016 to August 2018. Four hundred and eighty-one samples were submitted, of which 340 (70.7%) met the inclusion criteria of the audit. A urinary pathogen was identified in 181 (53.2%) specimens, of which 148 (81.8%) were E. coli, 13 (7.2%) other coliforms and 20 (11.0%) Staphylococcus saprophyticus. Of the E. coli isolates, 109 of 148 (73.6%, 95% CI 66.6-80.7) were susceptible to trimethoprim, 144 of 144 (100%, 95% CI 100-100) to nitrofurantoin and 143 of 148 (96.6%, 95% CI 93.7-99.5) to cefalexin. Of the urinary pathogens, 139 of 185 (75.1%, 95% CI 68.9-81.4) were susceptible to trimethoprim, 164 of 177 tested (92.7%, 95% CI 88.8-96.5) to nitrofurantoin and 166 of 178 tested (93.3%, 95% CI 89.6-96.9) to cefalexin. Overall, a uropathogen resistant to trimethoprim was detected in 13.5%, to nitrofurantoin in 3.8%, and to cefalexin in 3.5% of samples tested.

CONCLUSION

Similar rates of resistance to trimethoprim were seen in women 15-55 years old presenting with cystitis compared with unselected samples submitted from the general community. Given the high rates of resistance, trimethoprim is no longer appropriate as an empiric treatment option for cystitis in this group. Nitrofurantoin or cefalexin are appropriate alternative empiric treatment options. Given the current recommendation that a urine sample should not be submitted to the laboratory from women with uncomplicated cystitis, ongoing audits will be required to ensure that empiric treatment recommendations remain appropriate.