Efficacy of quinupristin-dalfopristin against methicillin-resistant Staphylococcus aureus and vancomycin-insensitive S-aureus in a model of hematogenous pulmonary infection

Background: Quinupristin-dalfopristin (Q-D) is a mixture of quinupristin and dalfopristin, which are semisynthetic antibiotics of streptogramin groups B and A, respectively. Methods: We compared the effect of Q-D to that of vancomycin (VCM) in murine models of hematogenous pulmonary infections caused by methicillin-resistant Staphylococcus aureus (MRSA) and VCM-insensitive S. aureus (VISA). Results: Treatment with Q-D resulted in a significant decrease in the number of viable bacteria in the lungs of mice in an MRSA infection model [Q-D 100 mg/kg, Q-D 10 mg/kg, VCM and control (mean+/-SEM): 2.99+/-0.44, 6.38+/-0.32, 5.75+/-0.43 and 8.40+/-0.14 log(10) CFU/lung, respectively]. Compared with VCM, high-dose Q-D significantly reduced the number of bacteria detected in the VISA hematogenous infection model [Q-D 100 mg/kg, Q-D 10 mg/kg, VCM and control (mean+/-SEM): 5.17+/-0.52, 7.03+/-0.11, 7.10+/-0.49 and 7.18+/-0.36 log(10) CFU/lung, respectively]. Histopathological examination confirmed the effect of Q-D. Conclusion: Our results suggest that Q-D is potent and effective in the treatment of MRSA and VISA hematogenous pulmonary infections. Copyright (C) 2004 S. Karger AG, Basel.