Real-life experience with IV fosfomycin in Canada: Results from the Canadian LEadership on Antimicrobial Real-life usage (CLEAR) registry

Objectives: Data on the use of intravenous (IV) fosfomycin in Canada are limited. Using data captured by the Canadian LEadership on Antimicrobial Real-life usage (CLEAR) registry, we report the use of IV fosfomycin in Canadian patients.

Methods: The CLEAR registry uses the web-based data management program, REDCap^TM (https://rcsurvey.radyfhs.umanitoba.ca/surveys/?s=F7JXNDFXEF) to facilitate clinicians' entering of details associated with their clinical experiences using IV fosfomycin.

Results: Data were available for 59 patients treated with IV fosfomycin. The most common infections treated were: bacteraemia or sepsis (25.4% of patients), complicated urinary tract infection (20.3%), ventilator-associated bacterial pneumonia (18.6%), and hospital-acquired pneumonia (13.6%). IV fosfomycin was used to treat Gram-negative (88.1%) and Gram-positive (10.2%) infections. The most common pathogens treated were carbapenem-resistant Enterobacterales (44.1%), multidrug-resistant Pseudomonas aeruginosa (18.6%), vancomycin-resistant Enterococcus faecium (5.1%), and methicillin-resistant Staphylococcus aureus (3.4%). IV fosfomycin was primarily used due to resistance to initially prescribed therapies (69.5%), frequently in combination with other agents (86.4%). Microbiological success (eradication/presumed eradication) occurred in 77.4% of patients, and clinical success (clinical cure/improvement) occurred in 62.5%. Overall, 15.3% of patients died because of their infection. Adverse effects were not documented in 73.1% of patients, and no patient discontinued therapy because of an adverse effect.

Conclusions: In Canada, IV fosfomycin is used primarily as directed therapy to treat a variety of severe infections caused by Gram-negative and Gram-positive bacteria. It is primarily used in patients infected with bacteria resistant to other agents and as part of combination therapy. Its use is associated with relatively high microbiological and clinical cure rates, and it has an excellent safety profile.