IN-VITRO SUSCEPTIBILITIES OF BORDETELLA-PERTUSSIS AND BORDETELLA-PARAPERTUSSIS TO 2 KETOLIDES (HMR-3004 AND HMR-3647), 4 MACROLIDES (AZITBROMYCIN, CLARITHROMYCIN, ERYTHROMYCIN-A, AND ROXITHROMYCIN), AND 2 ANSAMYCINS (RIFAMPIN AND RIFAPENTINE)

When tested by agar dilution on Mueller-Hinton agar supplemented with 5% horse blood, the ketolides HMR 3004 and HMR 3647 were slightly more active (MIC at which 90% of the isolates were inhibited [MIC90], 0.03 mu g/ml) against Bordetella pertussis than azithromycin, clarithromyc in, erythromycin A, and roxithromycin. Azithromycin (MIC90, 0.06 mu g/ ml) was the most active compound against B. parapertussis. Rifampin an d rifapentine were considerably less active.