Antimicrobial activity and spectrum of LY146032, a lipopeptide antibiotic, including susceptibility testing recommendations

Abstract

LY146032, a new lipoprotein, was found to have a spectrum of gram-positive antimicrobial activity that includes activity against staphylococci (methicillin and susceptible and resistant), beta-hemolytic Streptococcus spp., pneumococci, viridans group Streptococcus spp., anaerobic gram-positive cocci, Clostridium spp., and enterococci. The new lipopeptide was generally bactericidal and showed more rapid killing of Listeria spp. (MIC, 1 to 2 .mu.g/ml) and staphylococci than either vancomycin or teicoplanin. The 30-.mu.g disk was preferred to the 15-.mu.g disk on the basis of the preliminary interpretive criteria for susceptibility which indicated zone diameters of .gtoreq. 16 mm for susceptible strains (MIC, .ltoreq. 2.0 .mu.g/ml) and .ltoreq. 12 mm for resistant strains (MIC, .ltoreq. 8.0 .mu.g/ml). These criteria are valid pending the testing of additional gram-positive strains which have LY146032 MICs of .gtoreq. 8 .mu.g/ml.