Retrospective evaluation of intravenous fosfomycin in multi-drug resistant infections at a tertiary care hospital in Lebanon

Abstract

Introduction: Fosfomycin has re-emerged as a possible therapeutic alternative for the treatment of resistant bacterial pathogens. Its main mechanism of action is the inhibition of the initial step of cell wall synthesis and is active against both Gram-positive and Gram-negative bacteria. However, its clinical effectiveness against multidrug resistant bacteria remains largely unknown. Therefore, we aim to evaluate the clinical and microbiological effectiveness of intravenous fosfomycin as well as its safety in a tertiary care teaching hospital in Lebanon.

Methodology: This is a retrospective chart review of adult patients who had presented to the hospital and were treated with intravenous fosfomycin for at least 24 hours for any type of infection between 2014 and 2019.

Results: Among 31 episodes treated with intravenous fosfomycin, 68% had an overall favorable clinical response. In 84% of the episodes, fosfomycin was administered in combination with other antibiotics, commonly tigecycline. Of those with available cultures at end of therapy, 73% achieved microbiological success. No relapse was documented within 30 days of completion of therapy. In the episodes secondary to resistant pathogens, the rates of favorable clinical outcome and microbiological success at the end of therapy were 71% and 73%, respectively. Fosfomycin resistance developed in two cases and mild adverse events occurred in 65% of the episodes during the course of treatment.

Conclusions: Fosfomycin is a safe and effective option in the treatment of multi-drug resistant infections. Nevertheless, careful stewardship is important to maintain its efficacy and to reduce the risk of selection of antimicrobial resistance.