title: Comparative in-vitro activities of A-56268 (TE-031) and erythromycin against 306 clinical isolates.
abstract: The inhibitory (MIC) and bactericidal (MBC) activities of a new macrolide A-56268 (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, Haemophilus influenzae 8/8-16, H. parainfluenzae 8/8-16, Legionella pneumophila 0.06/0.5, methicillin-sensitive isolates of Staphylococcus aureus 0.5/1, and coagulase negative staphylococci 1/8, methicillin resistant isolates of Staph. aureus and coagulase negative staphylococci greater than 16/ greater than 16, Streptococcus pneumoniae 0.06/0.125, streptococcus Group A 0.06/2-4, streptococcus Group B 0.06/8- greater than 16, streptococcus Groups C and G 0.125/8 and Str. faecalis 4/64. Compared with erythromycin, A-56268 had greater inhibitory and bactericidal activity against isolates of L. pneumophila, with an MIC90 16-fold less and an MBC90 eight-fold less than that of erythromycin. Except for enterococci, 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 clinical importance of the differences between these two macrolides will depend on the pharmacokinetic and tissue penetration properties of the new compound.
authors.affiliation: Department of Medicine, Veterans Administration Medical Center, Albany, New York 12208.
authors.forename: D M
authors.initials: DM
authors.lastname: Liebers
authors.forename: A L
authors.initials: AL
authors.lastname: Baltch
authors.forename: R P
authors.initials: RP
authors.lastname: Smith
authors.forename: M C
authors.initials: MC
authors.lastname: Hammer
authors.forename: J V
authors.initials: JV
authors.lastname: Conroy
authors.forename: M
authors.initials: M
authors.lastname: Shayegani
mesh_terms: D001420:Bacteria, Aerobic / Q000187:drug effects*; D017291:Clarithromycin; D004917:Erythromycin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D006801:Humans; D008826:Microbial Sensitivity Tests
chemical_list: D004917:Erythromycin; D017291:Clarithromycin