Oral temafloxacin versus vancomycin for therapy of experimental endocarditis caused by methicillin-resistant Staphylococcus aureus

We compared oral temafloxacin, a new fluoroquinolone agent, with vancomycin, each with and without rifampin, in the therapy of rats with aortic valve endocarditis caused by a clinical isolate of methicillin-resistant Staphylococcus aureus. The temafloxacin, vancomycin, and rifampin MICs and MBCs were 0.78 and 1.56, 1.56 and 3.13, and less than 0.024 and 0.78 microgram/ml, respectively. The animals were classified into the following six treatment groups: vancomycin (60 mg/kg) +/- rifampin (6 mg/kg) each intramuscularly every 12 h for 5 days; temafloxacin (100 mg/kg) orally +/- rifampin (6 mg/kg) intramuscularly every 12 h for 5 days; rifampin (6 mg/kg) intramuscularly every 12 h for 5 days; and untreated controls. All regimens with either vancomycin or temafloxacin resulted in improved survival over controls, but only temafloxacin regimens resulted in a significant reduction in bacterial counts in vegetations. These data support further investigation of the efficacy of temafloxacin in treating serious infections caused by methicillin-resistant S. aureus.