A COMPARISON OF THE INVITRO ACTIVITY OF CLARITHROMYCIN, A NEW MACROLIDE ANTIBIOTIC, WITH ERYTHROMYCIN AND OTHER ORAL-AGENTS

On the basis of minimum inhibitory concentrations clarithromycin (6-O-methylerythromycin), a new macrolide, was found to be slightly more active than erythromycin against Staphylococcus aureus, enterococci. Moraxella catarrhalis, Gardnerella vaginalis, Bacteroides fragilis (sensu stricto) and B. ureolyticus and slightly less active against coagulase-negative staphylococci, α- and β-haemolytic streptococci, Haemophilus influenzae, Campylobacter coli/jejuni and the B. melaninogenicus/oralis groups. There was complete cross-resistance between the two agents. Reports of potentiation of the activity against Haemophilus influenzae of clarithromycin by its own metabolite and by human serum appear to operate in vivo, and therefore the new agent shows great promise, especially for the treatment of respiratory tract infections. © 1991.