1690. Oral Fosfomycin for the Treatment of Bacterial Prostatitis

Abstract Background Bacterial prostatitis (BP) is notoriously difficult to treat. Few antibiotics penetrate the prostate well, and antibiotic resistance can further restrict options. A small body of recent literature suggests fosfomycin, a bactericidal antibiotic that can treat multidrug resistant (MDR) organisms and has little cross-resistance, may both effectively penetrate the prostate and treat BP. This study sought to add to the limited literature on the efficacy and safety of fosfomycin for BP. Methods Patients treated for BP with fosfomycin between November 2009 and May 2019 at the San Diego VAMC were retrospectively examined. Patients were excluded if they died within 6 months of completion of fosfomycin or if fosfomycin was used for less than half of the treatment course. If fosfomycin was used to treat a urinary tract infection (UTI), an infectious disease physician determined if the UTI may have been undiagnosed BP. Outcomes were clinical and microbiological cure at 6 months and adverse events to fosfomycin reported during the trial period. Results The study included 29 patient cases. All but one had chronic BP. Most initially presented outpatient (66%). Almost all had prior occurrences of BP treated with antibiotics (90%). The most common pathogen was E. coli (73%), and 87% of all pathogens were MDR. The most common fosfomycin dosing regimen was 3g PO q48h (66%), with 3g PO q24h as the next most common (21%). Less than half of patient cases received fosfomycin courses > 28 days (38%), while the remaining received courses < 14 days (62%). At 6 months, 48% achieved clinical cure and 44% achieved microbiological cure. When comparing those who received courses > 28 days vs. courses < 14 days, clinical cure was achieved in 55% vs. 44% and microbiological cure in 56% vs. 39%, respectively. Adverse events were reported in 6 unique patients (27%), mostly diarrhea with one instance of nausea. Conclusion Fosfomycin may be a safe and effective alternative for the treatment of chronic BP. Treatment courses longer than 4 weeks may be more effective than courses shorter than 2 weeks with a similar rate of adverse events. This study also highlights inpatients as a relevant BP population and a need for provider education on identifying BP and prescribing optimal durations of therapy. Disclosures All Authors: No reported disclosures