High antimicrobial resistance in urinary tract infections in male outpatients in routine laboratory data, Germany, 2015 to 2020

Background Evidence on the distribution of bacteria and therapy recommendations in male outpatients with urinary tract infections (UTI) remains insufficient. Aim We aimed to report frequency distributions and antimicrobial resistance (AMR) of bacteria causing UTI in men and to identify risk factors for resistance of Escherichia coli against trimethoprim (TMP) and ciprofloxacin (CIP). Methods We conducted a retrospective observational study using routinely collected midstream urine specimens from 102,736 adult male outpatients sent from 6,749 outpatient practices to nine collaborating laboratories from all major regions in Germany between 2015 and 2020. Resistance in E. coli was predicted using logistic regression. Results The three most frequent bacteria were E. coli (38.4%), Enterococcus faecalis (16.5%) and Proteus mirabilis (9.3%). Resistance of E. coli against amoxicillin (45.7%), TMP (26.6%) and CIP (19.8%) was common. Multiple drug resistance was high (22.9%). Resistance against fosfomycin (0.9%) and nitrofurantoin (1.9%) was low. Resistance of En. faecalis against CIP was high (29.3%). Isolates of P. mirabilis revealed high resistance against TMP (41.3%) and CIP (16.6%). The CIP and TMP resistance was significantly higher among bacteria derived from recurrent UTI (p < 0.05). Age ≥ 90 years, recurrent UTI and regions East and South were independently associated with AMR of E. coli against TMP and CIP (p < 0.05). Conclusion The most frequent UTI-causing pathogens showed high resistance against TMP and CIP, empirical therapy is therefore likely to fail. Apart from intrinsically resistant pathogens, susceptibility to fosfomycin and nitrofurantoin remains sufficient. Therefore, they remain an additional option for empirical treatment of uncomplicated UTI in men.