Comparative in-vitro activities of A-56268 (TE-031) and erythromycin against 306 clinical isolates

Abstract

The inhibitory (MIC) and bactericidal (MBQ activities of a new macrolide A-S6268 (TE-031) against 306 clinical aerobic bacterial isolates was compared with that of erythromycin. The MIC₉₀/MBC₉₀, ratios for A-56268 were: Campylobacter jejuni 4/16, Haemophitus influeniae 8/8–16, H. parabtfluenzae 8/8–16, Legionella pneumophila 0·06/0·5, methicillin-sensitive isolates of Staphylococcus aureus 0·5/1, and coagulase negative staphylococci 1/8, methkillin resistant isolates of Staph. aureus and coagulase negative staphylococci L. pneumophila, with an MIC₉₀ 16-fold less and an MBC₉₀ eight-fold less than that of erythromycin. Except for cnterococd, A-56268 showed inhibitory activity equal to or greater than that of penicillin G against isolates of streptococci and an MIC two-fold less than that of erythromycin. For other strains tested, the inhibitory and bactericidal activities of A-56268 and erythromycin were similar. The dinical importance of the differences between these two macrolides will depend on the pharmacokinetk and tissue penetration properties of the new compound.