Fosfomycin susceptibility among Escherichia coli causing urinary tract infection in a tertiary care centre in Western Maharashtra

Background and objective: Urinary tract infection(UTI) is one of the most common bacterial infections encountered in clinical practice. UTIs caused by extended-spectrum beta-lactamase (ESBL) AmpC and metallo-beta-lactamase (MBL) producing Escherichia coli (E. coli) are difficult to treat. Fosfomycin is an old antibiotic that has excellent bactericidal activity against a wide range of bacteria. This study aimed to determine the fosfomycin susceptibility of E. coli causing UTI in a tertiary care hospital in Western Maharashtra, India.

Material and methods: The study was conducted at a tertiary care center in Pune, a city of Western Maharashtra, India. Urine samples from UTI cases yielding significant (> 1x 105 cfu/ml) growth of E. coli were included in study. E. coli isolates were tested for susceptibility to fosfomycin and a panel of antimicrobial agents by Kirby Bauer disc diffusion method. All the isolates were tested for production of ESBL, AmpC and MBL.

Result: A total of 88 E. coli were isolated of which, 47 (53.40%) and 41 (46.59%) were from male and female patients respectively. Of the total E. coli isolates, 58 (65.9%) were from in-patient cases. Multi-drug resistance was found in 69 (78.40%) isolates and remaining 19 (21.6%) were resistant to different antimicrobials tested. All (100%) the MDR and non-MDR isolates were sensitive to fosfomycin. Highest resistance was present against nalidixic acid (93.8%) while resistance was least against nitrofurantoin (15.91%), piperacillin/tazobactam (17.1%) and meropenem (18.18%). Of the total, 35 (50.72%) isolates were both AmpC and ESBL producers while 11 (15.94%) and 8 (11.59%) were only AmpC and ESBL producers respectively. MBL was positive in 15 (21.73%) of E. coli isolates. All those isolates tested sensitive to fosfomycin.

Conclusion: The study revealed that fosfomycin had excellent activity against MDR E. coli causing UTI in our area.

IMC J Med Sci. 2023; 17(1): 008. DOI: https://doi.org/10.55010/imcjms.17.008

*Correspondence: Dr. Sameena Khan, Department of Microbiology, Dr. D. Y. Patil Medical College, Hospital and Research Centre, Dr. D. Y. Patil Vidyapeeth, Pimpri, Pune, Maharashtra, India. E-mail: sameenak27@gmail.com