Efficacy of Fosfomycin against Planktonic and Biofilm-Associated MDR Uropathogenic Escherichia coli Clinical Isolates

Abstract

Urinary tract infections (UTI) are a severe public health problem and are caused mainly by the uropathogenic Escherichia coli (UPEC). Antimicrobial resistance and limited development of new antimicrobials have led to the reuse of old antibiotics such as fosfomycin. The aim of this study was to evaluate the in vitro efficacy of fosfomycin on a collection of multidrug-resistant (MDR) UPEC and the degradative activity on biofilm producers. A total of 100 MDR UPEC clinical isolates were collected from patients at Mexican second- and third-level hospitals. Microorganism identification was performed using an automated system, the evaluation of the susceptibility of clinical isolates to fosfomycin was performed using the resazurin microtiter assay, and the identification of biofilm producers and the effect of fosfomycin in biofilms were evaluated using the crystal violet method. Among planktonic MDR UPEC, 93% were susceptible to fosfomycin. Eighty-three MDR UPEC were categorized as weak (39.8%), moderate (45.2%), and strong (14.5%) biofilm producers. Fosfomycin exhibited degradative activity ranging from 164.4 µg/mL to 1,045 µg/mL. Weak producers required statistically lower concentrations of fosfomycin to destroy the biofilm, contrary to moderate and strong producers. In conclusion, fosfomycin could be an option for the treatment of infections caused by MDR UPEC, for which the antimicrobial treatment is more often becoming limited.

Uropathogenic Escherichia coli (UPEC)-Associated Urinary Tract Infections: The Molecular Basis for Challenges to Effective Treatment

“…Like nitrofurantoin, the resistance rates to fosfomycin among UPEC remains low, preserving its clinical utility in the treatment of UTIs [ 179 , 188 ]. The mechanism of action is also unique, meaning that the development of co-resistance is unlikely [ 189 ].…”

Fosfomycin: An old antibiotic and new perspectives. A review

“…В другом недавнем исследовании H. Dzib-Baak и соавт. (Мексика) изучалась эффективность фосфомицина in vitro в отношении 100 клинических изолятов уропатогенной E. сoli с МЛУ, а также деградационная активность в отношении продуцентов биопленки [14]. Среди планктонных изолятов E. сoli с МЛУ 93% проявили чувствительность к фосфомицину; 83 изолята E. сoli с МЛУ продуцировали биопленки и характеризовались как слабые (39,8%), умеренные (45,2%) и сильные (14,5%) продуценты.…”