Fosfomycin: A potential oral option for treatment of urinary tract infections in Sri Lanka in the context of high antibiotic resistance.

INTRODUCTION: Fosfomycin is an effective treatment for urinary tract infections (UTIs). It is not currently used in Sri Lanka to treat UTIs. Hence, this study was conducted to assess the fosfomycin susceptibility for E. coli in urinary isolates, with an aim to find the usability of fosfomycin in the context of high antibiotic resistance.

METHODS: E. coli isolates were identified by the colony appearance and by performing biochemical tests for the urinary coliform isolates collected from two different hospitals in Western Province Sri Lanka, during the period of November 2021 to February 2022. Susceptibility to fosfomycin 200 μg disc was performed following the Clinical Laboratory Standard Institute (CLSI) disc diffusion method.

RESULTS: A total of 101 E. coli isolates from both oncology patients (52.5%) and non-oncology patients (47.5%) were identified and included in the study. The study sample showed majority of females (63.3%). Ampicillin showed the highest resistance rate (72.2%) while fosfomycin was the only antibiotic that showed 100% in vitro susceptibility to all the tested clinical isolates. The overall presence of multidrug-resistant (MDR) and carbapenem-resistant (CR) E. coli were 47.5% and 9.9% respectively.

CONCLUSIONS: Fosfomycin is a potential antibiotic option especially for MDR and CR organisms, with 100% in vitro susceptibility. Further studies involving multiple centers, with larger sample size and clinical efficacy studies would be important to assess the potential use of fosfomycin especially for the treatment of UTI-causing MDR and CR organisms.