Comparative in vitro activity of coumermycin against methicillin-resistant Staphylococcus aureus

Coumermycin was the most active agent in vitro against methicillin-resistant Staphylococcus aureus when compared with fusidic acid, imipenem, rifampin, trimethoprim-sulfamethoxazole, and vancomycin. The MICs of coumermycin ranged from 0.002 to greater than 4 micrograms/ml and from 0.5 to greater than 4 micrograms/ml for inocula of 10(4) and 10(6) CFU/ml, respectively. The combination of coumermycin with either cephalothin or ciprofloxacin showed some synergy; antagonism was found with gentamicin.