Antibiotic Resistance Patterns Among Uropathogens in Female Outpatients Affected by Uncomplicated Cystitis: Focus on Fosfomycin Trometamol

Abstract

To report the resistance rate against fosfomycin trometamol among outpatient women with symptoms related to UTI during a 6 years-period in a multicentre cross-sectional study. Urinary samples were collected from three high volume laboratories from January 2015 to December 2020. The pattern of resistance to fosfomycin was analysed by using the Vitek II automated system. During the study period 7,289 urinary samples were collected and 8,321 strains were analysed. Escherichia coli was the most common isolated uropathogens (n=6,583, 79.1%). The mean resistance rate against fosfomycin was 9.7% (ranging from 7.1 to 11.3). No statistically significant difference was found between the three laboratories (p=0.53). There was no significant increase in resistance rate during the study period. The mean resistance rate against fosfomycin was higher among ESBL-producing bacteria when compared with no ESBL-producing strains (10.8% vs 7.9%, p<0.001). Uropathogens isolated from women affected by cystitis remained highly susceptible to fosfomycin. Our findings confirm recommendations in international guidelines that advocate fosfomycin trometamol for empirical treatment of uncomplicated cystitis in women.