Antimicrobial Susceptibilities of Urinary Extended-spectrum β-lactamase Escherichia coli to Fosfomycin

OBJECTIVES: Escherichia coli (E. coli)-induced urinary tract infection (UTI) is a common infection associated with frequent use of antibiotics and the increase in global antibiotic resistances. We aimed to determine the susceptibility profile of extended-spectrum β-lactamase (ESBL) producing E. coli isolated from the urinary samples to fosfomycin and other antibiotics. METHODS: We retrospectively analyzed urine samples with ESBL-producing E. coli isolates obtained between January 2018 and December 2019 in the Microbiology Section, Salmaniya Medical Complex, Bahrain. We collected and analyzed all the E. coli urinary isolates’ data and their antibiotic susceptibility patterns. RESULTS: The study included 3044 E. coli isolates with 50.6% obtained in 2018 and 49.4% in 2019; 38.1% (1161 isolates) were ESBL E. coli, and 0.7% (21 isolates) were carbapenem-resistant (Enterobacteriaceae) (CRE). There were 1161 (38.1%) isolates with ESBL-producing E. coli, with 37.3% isolated in 2018 and 39.0% isolated in 2019. The antibiotic susceptibility of ESBL-producing E. coli during the study period showed susceptibility to trimethoprim/sulfamethoxazole in 46.1% of isolates (50.2% in 2018 dropped to 41.9% in 2019), to ciprofloxacin in 49.0% of isolates (49.5% in 2018 dropped to 48.4% in 2019), to nitrofurantoin in 91.8% of isolates (94.3 in 2018 dropped to 89.3% in 2019), and to fosfomycin in 97.6% of isolates (98.8% in 2018 dropped to 96.3% in 2019). CONCLUSIONS: ESBL-producing E. coli is an important cause of UTI in Bahrain. Fosfomycin is a very effective oral antimicrobial that retains high efficacy against ESBL-producing E. coli, which helps decrease the need for parenteral therapy and, consequently, hospitalization.