Background: Wide-spectrum antibiotics have been favored to treat acute uncomplicated cystitis (AUC) for a long time, leading to the emergence of multi-drug resistant bacteria. We hypothesize that narrow-spectrum antibiotics might mitigate the issue and aim to investigate the clinical efficacy of cefaclor in patients with AUC. Methods : We retrospectively reviewed the clinical data of female outpatients with AUC treated with cefaclor and evaluated the safety and clinical efficacy. Clinical cure was defined as the elimination of clinical symptom under 4 white blood cells (WBCs) per high power field on microscopy. Results : Overall, 223 women with AUC were enrolled. Escherichia coli was the dominant pathogen (n=160; 68.6%), followed by Klebsiella species and E. coli -extended spectrum β-lactamase (ESBL) (n=19; 8.1% and n=18; 7.7%). Overall success rate was 94.0% (n=219) and susceptibility rate of cefazolin was 84.1%, which was close to that of levofloxacin (82.9%). Ampicillin showed the lowest rate of 63.7% with a significantly greater resistance rate of 35.3% among all antibiotics (P<0.001). In the subgroup analysis, the success rate in patients with resistance to levofloxacin or cefazolin was 100% (n=24) or 93.3% (n=14). The rate in patients with resistance to both antibiotics was 60.0% (n=9), and the pathogens in the other 40.0% (n=6) of patients with treatment failure were E. coli -ESBL. Conclusion : Cefaclor showed excellent efficacy in AUC patients, even in those with in vitro resistance to cefazolin or levofloxacin. Cefaclor may be considered as a first-line option in patients with AUC and a second-line option for those with levofloxacin treatment failure.

Background: Wide-spectrum antibiotics have been favored to treat acute uncomplicated cystitis (AUC) for a long time, leading to the emergence of multi-drug resistant bacteria. We hypothesize that narrow-spectrum antibiotics might mitigate the issue and aim to investigate the clinical efficacy of cefaclor in patients with AUC.Methods: We retrospectively reviewed the clinical data of female outpatients with AUC treated with cefaclor and evaluated the safety and clinical efficacy. Clinical cure was defined as the elimination of clinical symptom under 4 white blood cells (WBCs) per high power field on microscopy.Results: Overall, 223 women with AUC were enrolled. Escherichia coli was the dominant pathogen (n=160; 68.6%), followed by Klebsiella species and E. coli-extended spectrum β-lactamase (ESBL) (n=19; 8.1% and n=18; 7.7%). Overall success rate was 94.0% (n=219) and susceptibility rate of cefazolin was 84.1%, which was close to that of levofloxacin (82.9%). Ampicillin showed the lowest rate of 63.7% with a significantly greater resistance rate of 35.3% among all antibiotics (P<0.001). In the subgroup analysis, the success rate in patients with resistance to levofloxacin or cefazolin was 100% (n=24) or 93.3% (n=14). The rate in patients with resistance to both antibiotics was 60.0% (n=9), and the pathogens in the other 40.0% (n=6) of patients with treatment failure were E. coli-ESBL.Conclusion: Cefaclor showed an excellent efficacy in AUC patients, even in those with resistance to cefazolin or levofloxacin. Cefaclor has the potential to be the first-line and second-line therapies for patients with levofloxacin treatment failure.