Internal Medicine Residents' Perceptions of Fosfomycin use – a Brief Report

Abstract— Background: Fosfomycin is approved by the FDA for treating uncomplicated cystitis caused by Escherichia coli and Enterococcus faecalis. However, it is often prescribed off-label for broader indications, with limited data on physician knowledge and practice patterns. Methods: We surveyed residents in the Yale New Haven Internal Medicine Residency program across three teaching hospitals to assess awareness, prescribing habits, and perceived indications for fosfomycin. Results: Seventy-eight residents responded (58% response rate); 89.7% were familiar with fosfomycin, and 71.4% had prescribed it. The most common indication was uncomplicated cystitis (94.3%), followed by pyelonephritis (41.4%) and prostatitis (32.9%). E. coli (71.4%) and Klebsiella pneumoniae (68.6%) were the most frequently selected organisms. Only 30% correctly identified uncomplicated cystitis as the sole FDA-approved indication, and no responses fully aligned with the approved spectrum of use. Conclusion: Internal medicine trainees demonstrated significant gaps in knowledge regarding fosfomycin’s approved role. Educational efforts are needed to promote judicious prescribing and preserve its effectiveness against multidrug-resistant pathogens.