The Detection of Fosfomycin-Modifying Enzymes (fos) in Uropathogenic Enterobacterale, Azerbaijan, Iran

Area of Science:

• Microbiology
• Infectious Diseases
• Antimicrobial Resistance

Background:

• Enterobacteriaceae are primary causes of urinary tract infections (UTIs).
• Increasing global prevalence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) Enterobacteriaceae in UTIs poses a significant challenge.
• Fosfomycin is a potential alternative antibiotic for treating resistant UTI pathogens.

Purpose of the Study:

• To determine the frequency of fosfomycin resistance in Enterobacteriaceae isolated from UTIs.
• To identify and quantify fosfomycin resistance genes in these isolates.
• To evaluate fosfomycin's efficacy as a treatment option against MDR Enterobacteriaceae in UTIs.

Main Methods:

• Urine samples were collected and cultured using standard microbiological protocols.
• Antimicrobial susceptibility testing for fosfomycin was performed on 211 Enterobacteriaceae isolates using agar dilution and disk agar diffusion methods.
• Polymerase chain reaction (PCR) was employed to detect and analyze fosfomycin resistance genes (fosC, fosX, fosA3, fosA, fosB2, fosB, fosC2).

Main Results:

• A low frequency of fosfomycin resistance was observed: 6.6% by disk agar diffusion and 7.1% by MIC assays.
• The Minimum Inhibitory Concentration (MIC) values indicated moderate resistance, with MIC50 at 8 μg/mL and MIC90 at 16 μg/mL.
• Multidrug resistance (MDR) was prevalent, found in 80% of the isolates. Specific fosfomycin resistance genes were detected at varying frequencies, with fosC being the most common (33.3%).

Conclusions:

• Fosfomycin exhibits a low resistance rate among Enterobacteriaceae causing UTIs in the study region.
• Despite the presence of resistance genes, fosfomycin remains a valuable and effective antibiotic option for treating MDR Enterobacteriaceae-associated UTIs.
• Continued monitoring of fosfomycin resistance patterns and underlying genetic mechanisms is crucial.