[Combined effects of arbekacin with other antibiotics against methicillin-resistant Staphylococcus aureus. I. The combined effect of arbekacin with fosfomycin or clavulanic acid/ticarcillin].

As arbekacin (ABK) has a highly potent antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA), its combined effects with fosfomycin (FOM) and clavulanic acid/ticarcillin (CVA/TIPC) against MRSA were examined. The obtained results are summarized as follows. 1. Against MRSA either combination, FOM+ABK or CVA/TIPC+ABK showed a strong antibacterial effect at the MIC or the sub MIC of ABK in the blood expected from clinical observations. The MIC of ABK by the combination use seemed to be equivalent to the MBC value. 2. Effective concentrations of antibiotics in these combinations appeared to be strongly dependent on the effective concentration of ABK and less dependent on that of FOM or CVA/TIPC. Therefore, the antibacterial activity of a combination seems to mostly depend on the antibacterial activity and the concentration of ABK. 3. As FOM and CVA/TIPC have antibacterial activities against Pseudomonas aeruginosa, combinations of ABK with these antibiotics are likely to be effective against double infection with P. aeruginosa in MRSA infected patients.