Clinical Efficacy of Fosfomycin for the Treatment of Complicated Lower Tract and Uncomplicated Urinary Tract Infections

Fosfomycin is an oral antibiotic with activity against multidrug resistant organisms, including vancomycin-resistant enterococcus (VRE) and extended-spectrum β-lactamase (ESBL) producing Enterobacteriaceae. However, there is currently no information describing effiacy of fosfomycin compared to other agents for healthcare associated UTIs. Additionally, there is minimal information characterizing the potential cost savings with utilization of fosfomcyin versus traditional therapies. This retrospective study evaluated clinical and economic outcomes of fosfomycin compared to matched controls. The controls were before the addition of fosfomycin to hospital formulary with recommended prescribing criteria. The fosfomycin group consisted of patients who were admitted to the hospital after the addition of fosfomycin to the hospital formulary with recommended prescribing criteria. Patients receiving fosfomycin for the treatment of UTI were matched to control patients based on pathogen, renal function, and presence of a lower UTI. A total of 86 patients were evaluated. The majority of patients received fosfomycin for the treatment of VRE (45.6%) and ESBL producing Enterbacteriaceae (16.3%) UTIs. Patients with a combination of allergies or documented resistance to fist line agents also received fosfomycin to treat Enterococcus (25.6%), Enterobacteriaceae (7.8%), or polymicrobial UTIs (4.7%). Doxycycline, nitrofurantoin, sulfamethoxazole/trimethoprim, meropenem, and linezolid were the most common antibiotics prescribed in the control group. The average days of treatment were lower in the fosfomycin group (2.93 vs. 7.19 days, p 0.99) and recurrence rates (4.7 vs. 4.7%, p>0.99). Additionally , the mean antibiotic cost per patient was lower in the  fosfomycin group ($106.74 vs. $269.55). Adding fosfomycin to formulary resulted in similar clinical success rates and lower cost for the  treatment of complicated lower and uncomplicated UTIs.