Fosfomycin Resistance in Clinical Isolates of Escherichia coli from Urinary Tract Infections in a Tertiary Care Hospital

Abstract

Background: Fosfomycin is called an old-new antibiotic, because it was reintroduced for the treatment of urinary tract infections. The rampant use of antibiotics has led to Fosfomycin resistance reported from different parts of the world. The purpose of this study was to find out the frequency of Fosfomycin resistance in clinical isolates of Escherichia coli (E. coli) from urinary tract samples.

Methods: This cross-sectional study, including n=314 patients, was conducted in the Microbiology laboratory at Pakistan Naval Ship SHIFA Hospital, Pakistan from January to June 2022. Urine samples were inoculated on agar at 37±2°C for 24-48hrs. The growth of E. coli was confirmed by API 10S as per recommended Clinical Laboratory Standard Institute (CLSI) guidelines. Susceptibility testing was performed by the standard Kirby Bauer Disc Diffusion method. The Chi-square test was applied to categorical variables. p-value ≤ 0.05 was considered statistically significant.

Results: Out of 314 clinical isolates, 171 (54.5%) were females and 143 (45.5%) were males (mean age 49±10.3 (6-81) years). Sixty-six (21%) isolates were found resistant to Fosfomycin while 248 (79%) were sensitive. A significant difference was found between the gender (p=0.035), whereas, 29 (17.0%) females and 37 (25.9%) males were found resistant to Fosfomycin.

Conclusion: The resistance to Fosfomycin is increasing and it is an impending threat as oral treatment options are limited in urinary tract infections. However, improved surveillance may help in controlling nosocomial infection along with the rational use of antibiotics can prevent and reduce its spread.

Keywords: Fosfomycin; Culture; Susceptibility; Urinary Tract Infections (UTIs).