In-vitro antimicrobial activity of HMR 3004 (RU 64004) against erythromycin A-sensitive and -resistant Corynebacterium spp. isolated from clinical specimens

We studied the in-vitro activity of HMR 3004 (RU 64004), a new ketolide, ag ainst 161 clinical isolates of Corynebacterium spp. including isolates resi stant to erythromycin A, josamycin and lincomycin. HMR 3004 was active agai nst all erythromycin A-sensitive isolates as well as against 75.8% and 45.4 % of erythromycin A-intermediate and -resistant isolates, respectively. In contrast, HMR 3004 was active against 40 (46.5%) of 86 isolates resistant t o erythromycin A, josamycin and lincomycin as well as against two isolates that were resistant to erythromycin A and lincomycin but not resistant (i.e . susceptible or intermediate) to josamycin.