Activity of HMR 3647 compared to those of six compounds against 235 strains of Enterococcus faecalis

Agar dilution was used to test the activities of HMR 3647, erythromycin A, azithromycin, clarithromycin, roxithromycin, clindamycin, and quinupristin-dalfopristin against 235 strains of Enterococcus faecalis. HMR 3647 was the most active compound (MICs at which 50 and 90% of the isolates are inhibited [MIC50 and MIC90, respectively] of 0.06 and 4.0 microg/ml, respectively). The MIC50 and MIC90 (with the MIC50 given first and the MIC90 given second; both in micrograms per milliliter) for other compounds were as follows: 4.0 and >32.0 for erythromycin A, 16.0 and >32.0 for azithromycin, 2.0 and >32 for clarithromycin, 32.0 and >32.0 for roxithromycin, 32.0 and >32.0 for clindamycin, and 8.0 and 16.0 for quinupristin-dalfopristin. All compounds were only bacteriostatic.