Comparative efficacy of trovafloxacin in experimental endocarditis caused by ciprofloxacin-sensitive, methicillin-resistant Staphylococcus aureus. Antimicrob. Agents Chemother

The new fluoroquinolone trovafloxacin was tested against a ciprofloxacin-sensitive, methicillin-resistant Staphylococcus aureus strain in the rabbit model of endocarditis. Trovafloxacin was more effective than van-comycin (CFU/g of vegetation, 2.65 6 1.87 versus 4.54 6 2.80 [mean 6 standard deviation]; P < 0.05) or ampicillin-sulbactam plus rifampin (4.9 6 1.1 CFU/g). The addition of ampicillin-sulbactam to trovafloxacin tended to reduce titers further. Staphylococcus aureus is a common cause of infective endo-carditis (26, 31). To achieve high cure rates for staphylococcal endocarditis, prolonged therapy is required with antibiotics that achieve bactericidal activity at the site of infection, the cardiac vegetation (1). Staphylococci have shown a remarkable capacity over the years to develop resistance against commonly used antibiotics. Early after the introduction of penicillin into clinical practice, they acquired a penicillinase which now makes the majority of staphylococci resistant to penicillin G (11). In the 1960s, the development of penicillinase-stable pen