Evaluation of susceptibility of fosfomycin among isolates from urine cultures: A study from Puducherry.

Introduction: The increasing drug resistance among Gram-negative uropathogens and a lack of effective oral antibiotics have limited the therapeutic options available for urinary tract infections (UTIs). This shortage of newer antibiotics has paved the way for considering the use of older antibiotics such as fosfomycin. This study aims to evaluate the susceptibility of isolates to fosfomycin.

Materials And Methods: In this descriptive study conducted over a period of 6 months, we processed 1500 urine samples. The isolates were subjected to susceptibility testing to fosfomycin, in addition to the regularly used urinary antibiotics, by Kirby-Bauer disc-diffusion method.

Results: Of 1500 urine samples processed, 582 samples yielded the growth of pathogens. accounted for 392 (67.3%) of the isolates. Among these isolates, lower rates of resistance were observed for imipenem (4.1%) and fosfomycin (13.3%). Relatively higher rates of resistance were observed for nitrofurantoin (35.5%) and amikacin (30.9%). Nalidixic acid, norfloxacin, gentamicin, cefotaxime, and cotrimoxazole showed a high resistance rate of 82.7%, 69.6%, 52.3%, 69.1%, and 71.4%, respectively. All antibiotics, except fosfomycin, were in routine clinical use in our hospital. The low resistance (13.3%) to fosfomycin is indicative of its utility as an excellent urinary antibiotic.

Conclusions: Uropathogenic isolates displayed excellent susceptibility to fosfomycin. These findings suggest the unexplored potential of fosfomycin as a superior therapeutic option for treating uncomplicated UTI.