Comparison of fosfomycin and teicoplanin in serum bactericidal activity against staphylococci

A serum bactericidal test was established employing human sera of volunteers after intravenous administration of fosfomycin (CAS 23155-02-4) and teicoplanin (CAS 61036-62-2) against 40 staphylococcal strains (20 Staphylococcus aureus and 20 coagulase-negative staphylococci, 10 of each group being susceptible and 10 being resistant to oxacillin). Median serum inhibitory titres were highest for fosfomycin against oxacillin-susceptible Staphylococcus aureus. In the three other groups of strains, the activity of fosfomycin was comparable to that of teicoplanin. The killing curves showed over 99% killing within 24 h for both antibiotics. Here, fosfomycin exerted a rapid killing activity within 4-6 h and was more effective in bacterial growth reduction. It can be concluded that fosfomycin and teicoplanin exerted comparable serum bactericidal antibacterial activity against staphylococci.