Activities of HMR 3004 (RU 64004) and HMR 3647 (RU 66647) compared to those of erythromycin, azithromycin, clarithromycin, roxithromycin, and eight other antimicrobial agents against unusual aerobic and anaerobic human and animal bite pathogens isolated from skin and soft tissue infections in humans.

The activities of HMR 3004 and HMR 3647 and comparator agents, especially macrolides, were determined by the agar dilution method against 262 aerobic and 120 anaerobic strains isolated from skin and soft tissue infections associated with human and animal bite wounds. HMR 3004 and HMR 3647 were active against almost all aerobic and fastidious facultative isolates (MIC at which 90% of the isolates are inhibited [MIC90], < or = 0.5 and 1 microg/ml, respectively) and against all anaerobes [Bacteroides tectum, Porphyromonas macacae (salivosa), Prevotella heparinolytica, Porphyromonas sp., Prevotella sp., and peptostreptococci] at < or = 0.25 and < or = 0.5 microg/ml, respectively, except Fusobacterium nucleatum (HMR 3004, MIC90 = 16 microg/ml; HMR 3647, MIC90 = 8 microg/ml) and other Fusobacterium species (MIC90, 1 and 2 microg/ml, respectively). In general, HMR 3004 and HMR 3647 were more active than any of the macrolides tested. Azithromycin was more active than clarithromycin against all Pasteurella species, including Pasteurella multocida subsp. multocida, Eikenella corrodens, and Fusobacterium species, while clarithromycin was more active than azithromycin against Corynebacterium species, Weeksella zoohelcum, B. tectum, and P. heparinolytica.