Evaluating antimicrobial effectiveness in acute uncomplicated cystitis: A retrospective single-center study

Background: Acute uncomplicated cystitis (AUC) is a urinary tract infection and is generally treated using antimicrobial therapy. Escherichia coli is the main causative agent of AUC. Recently, the prevalence of fluoroquinolone (FQ)-resistant-E. coli has demonstrated a noticeable increase. In this study, we aimed to investigate the effectiveness of appropriate antimicrobial treatment in AUC caused by E. coli in real-world clinical settings. Methods: This retrospective cohort study reviewed the records of patients with AUC treated at the urology department of Minami Cooperative Hospital between April 2016 and December 2020. Effectiveness was defined as clinical improvement. Results: The study cohort of 730 patients had a median age of 65.5 years (interquartile range, 57–78 years) and 23.2% were aged <55 years. E. coli was detected in 73.4% of patients, of whom 26.7% had levofloxacin (LVFX)-resistant strains. LVFX-resistant E. coli was associated with age ≥55 years and recurrent cases. Effectiveness was determined in 75.1% of cases, of which 75% complied with the Japanese or other international guidelines. The overall treatment effectiveness was highest with β-lactam (BL)/β-lactamase inhibitor (BLI) combinations (94.7%). The effectiveness of first- and third-generation cephalosporins (CPs) was 81.1–83.3%, and that of FQs and sulfamethoxazole–trimethoprim (ST) was 82.6–83.8%. For LVFX-resistant E. coli, the treatment effectiveness was highest (100%) with BL/BLI combinations, intermediate (75–81%) with first- and third-generation CPs and ST, and lowest (50%) with FQs. Conclusions: BL/BLI combinations had the highest effectiveness for the treatment of AUC.