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

Abstract

LY146032, a new lipopeptide, was found to have a spectrum of gram-positive antimicrobial activity that includes activity against staphylococci (methicillin 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 micrograms/ml) and staphylococci than either vancomycin or teicoplanin. The 30-micrograms disk was preferred to the 15-micrograms disk on the basis of the preliminary interpretive criteria for susceptibility which indicated zone diameters of greater than or equal to 16 mm for susceptible strains (MIC, less than or equal to 2.0 micrograms/ml) and greater than or equal to 12 mm for resistant strains (MIC, greater than or equal to 8.0 micrograms/ml). These criteria are valid pending the testing of additional gram-positive strains which have LY146032 MICs of greater than or equal to 8 micrograms/ml.