Comparative evaluation of fosfomycin activity with other antimicrobial agents against E.Coli isolates from urinary tract infections

Introduction: Fosfomycin is a broad spectrum anti-microbial agent with activity against various bacterial agents. It is a bactericidal antibiotic which interferes with cell wall synthesis. Fosfomycin is rapidly absorbed orally and majority of the drug is excreted unchanged in urine with very high concentration levels achieved in urine after a single oral dose. Urine levels remain high for prolonged period which makes it a suitable drug in the treatment of Urinary Tract Infections (UTI). E.coli is the most common organism causing the UTI. With the inappropriate and inadvertent use of higher antibiotics, these bacterial isolates have acquired multidrug resistance for which treatment options are limited. Aim: To evaluate the in-vitro activity of fosfomycin against uropathogenic E.coli and to compare its activity with the other anti-microbial agents Materials and Methods: This study was a prospective study done in the Department of Microbiology SVS Medical College, Mahbubnagar from Jan 2016 to Mar 2016. A total of 564 urine samples from suspected UTI cases were processed during the study period out of which 170 E.coli were isolated. Identification of the organisms were done by routine biochemical testing and anti-biotic sensitivity testing was done by Kirby-Bauer disc diffusion testing according to the CLSI guidelines (M100-S23) Results: A total of 170 E.coli isolates were tested for anti-biotic susceptibility. Out of 170 isolates 60 (35.30%) were isolated from males and 110 (64.70%) from females with male to female ratio of 1:1.83. Majority of the isolates were obtained from the age group of 21-30 years (25.8%). Antibiotics like fosfomycin, imipenem and methenamine mandelate showed the highest sensitivity with all the isolates (100%) being susceptible to these drugs. Whereas, least sensitivity was observed for amoxyclav (15.2%) followed by cefixime (16.4%) and norfloxacin (21%). Fosfomycin has shown very good in-vitro activity against all the tested isolates when compared with many other anti-biotics. Conclusion: In view of emergence of multidrug resistant pathogens, testing for old and forgotten antibiotics like fosfomycin is gaining importance. Because of its unique mechanism of action and low incidence of resistance it can be a potential therapeutic alternative in the treatment of UTI.