FONYL Injection FONYL contains Fosfomycin Sodium, a broad-spectrum bactericidal antibiotic. It acts by inhibiting N-acetylglucosamine enolpyruvyl transferase (MurA), an enzyme essential for the initial stage of bacterial cell wall peptidoglycan synthesis. This unique mechanism reduces cross-resistance with other antibiotic classes. It is indicated for treating serious, complex infections such as complicated urinary tract infections, osteomyelitis, hospital-acquired pneumonia, and systemic bacterial infections caused by susceptible Gram-positive and Gram-negative organisms (including multi-drug resistant strains).