Time trend of prevalence and susceptibility to nitrofurantoin of urinary MDR Escherichia coli from outpatients

OBJECTIVES: To assess the time trend of the prevalence of urinary MDR Escherichia coli in Belgian outpatients (2005 versus 2011-12), the antibiotic susceptibility of urinary MDR E. coli, and the time trend of non-susceptibility to nitrofurantoin, i.e. first-line treatment for uncomplicated urinary tract infections (UTIs), of urinary MDR E. coli (2005 versus 2011-12). METHODS: In this secondary analysis of a multicentre study, which collected a convenience sample of voluntary participating laboratories (15 and 8 in 2005 and 2011-12, respectively), we analysed antimicrobial susceptibilities (ampicillin, amoxicillin/clavulanate, cefalotin, ciprofloxacin, nitrofurantoin and trimethoprim/sulfamethoxazole) of urinary E. coli. MDR was defined as resistance to three or more of these agents. The prevalence of MDR E. coli and its non-susceptibility to nitrofurantoin was compared between 2005 and 2011-12 using a generalized estimating equation model. RESULTS: MDR status could be determined for 9704 and 12512 urinary E. coli isolates from 7911 and 9441 patients in 2005 and 2011-12, respectively, with most patients being women (79% in both study periods). The prevalence of MDR increased from 28.4% (2758/9704) in 2005 to 34.3% (4286/12512) in 2011-12 (adjusted OR 1.305; 95% CI 1.220-1.397). Within the MDR isolates, the prevalence of nitrofurantoin non-susceptibility decreased from 23.2% (623/2684) in 2005 to 10.7% (455/4253) in 2011-12 (adjusted OR 0.424; 95% CI 0.363-0.494). CONCLUSIONS: Despite a high prevalence of MDR E. coli in urinary samples from Belgian outpatients, nitrofurantoin could still be recommended as first-line empirical treatment in uncomplicated UTIs.