Fosfomycin: A Substitute in Therapeutic Options for Extended Spectrum Beta-lactamase Producing Uropathogens

Abstract

Background: The emergence of antibiotic resistance among pathogens causing urinary tract infections (UTI) has made treatment options limited. The use of fosfomycin along with other drug combination can significantly address this problem. Our study aimed to identify the rate of resistance among uropathogens and their susceptibility patterns to fosfomycin along with other antibacterial agents.

Methods: The retrospective study was conducted at Jinnah Sindh Medical University in collaboration with Dr. Tahir Laboratory, Karachi. A total of 146 urine samples were included which were processed for antibacterial susceptibility testing by Kirby-Bauer disk diffusion method and rate of resistance for antibacterial agents especially fosfomycin were recorded. The statistical analysis was performed by using Chi squared tests and p>0.05 was considered statistically significant.

Results: The study reported lowest rate of resistance for fosfomycin among Escherichia coli 3(5.3%), Klebsiella pneumoniae 7(14%) and Pseudomonas aeruginosa 9(22.5%) in comparison with ampicillin, which showed resistance in 43(76.8%), 41(82%) and 39(97.5%) cases of E. coli, K. pneumoniae and P. aeruginosa respectively. The subgroup carbapenem resistant Enterobacteriaceae (CRE) and extended spectrum β-lactamases (ESBLs) producers were seen noticeably high in P. aeruginosa. Overall, the female to male ratio was 1.4:1 (87/59), showing female preponderance (p=0.02). A majority of patients belonged to adult age group (61.6%) followed by senior adults (23.2%, p=0.05).

Conclusion: High levels of resistance to commonly used antibiotics were observed. The increasing rate of resistance among Enterobacteriaceae to cephalosporin and ampicillin is an alarming situation. In this context, fosfomycin is an interesting alternative option in treatment of complicated and uncomplicated urinary tract infections.

Keywords: Antibiotic Resistance; Enterobacteriaceae; Extended Spectrum Beta Lactamase; Fosfomycin; Urinary Tract Infection.