Activity of meropenem, against Gram-positive bacteria

A new carbapenem antibiotic, meropenem, was shown to be active against a large number of Gram-positive bacteria. The drug inhibited penicillinase-positive and -negative, methicillin-susceptible staphylococci equally well. Among the comparative antimicrobials examined, only N-formimidoyl-thienamycin (imipenem) was two to four times more active than meropenem. Compared with vancomycin or methicillin, meropenem was 10-20 times more active. Strains of 11 species of streptococci were highly susceptible to meropenem; the geometric mean MICs of the drug for these species ranged from 0 multiplied by 01 to 0 multiplied by 04 mg/l. Meropenem was as bactericidal as imipenem and comparative bactericidal antimicrobials in killing-curve experiments. Strains of Ent. faecium, C. jeikeium , and L. monocytogenes were killed at a slower rate than streptococci or staphylococci.