OBJECTIVES: Tigecycline appears as an alternative therapy against methicillin-resistant Staphylococcus aureus (MRSA) with limited clinical experience. We evaluate the efficacy of tigecycline and its combination with rifampin in comparison to that for vancomycin in a rat model of foreign-body infection by MRSA. METHODS: A tissue-cage infection model were used; therapy with tigecycline, vancomycin, rifampin, tigecycline plus rifampin and vancomycin plus rifampin was administered intraperitoneally for 7 days. The antibiotic efficacy was evaluated in the tissue-cage fluid and in the coverslips (attached bacteria); the emergence of resistance was screened. RESULTS: Among monotherapies rifampin was the best treatment (decrease in log CFU/ml of tissue-cage fluid, 2.75) (P < 0.05). The addition of rifampin improved the efficacy of vancomycin (decrease, 2.28) and tigecycline (decrease, 1.56) in solitary; there were not significantly differences between tigecycline-rifampin (decrease, 3.39) and vancomycin-rifampin (decrease, 3.70), but only the latter was better than rifampin alone (P < 0.05). Resistant strains were only detected using rifampin alone. CONCLUSIONS: tigecycline alone was the least effective treatment. Tigecycline-rifampin prevented the emergence of rifampin resistance, thus allowing the benefits of rifampin over time against staphylococcal foreign-body infections, but its efficacy needs to be evaluated in comparison with other anti-MRSA combined therapies.
OBJECTIVES:Tigecycline appears as an alternative therapy against methicillin-resistant Staphylococcus aureus (MRSA) with limited clinical experience. We evaluate the efficacy of tigecycline and its combination with rifampin in comparison to that for vancomycin in a rat model of foreign-body infection by MRSA. METHODS: A tissue-cage infection model were used; therapy with tigecycline, vancomycin, rifampin, tigecycline plus rifampin and vancomycin plus rifampin was administered intraperitoneally for 7 days. The antibiotic efficacy was evaluated in the tissue-cage fluid and in the coverslips (attached bacteria); the emergence of resistance was screened. RESULTS: Among monotherapies rifampin was the best treatment (decrease in log CFU/ml of tissue-cage fluid, 2.75) (P < 0.05). The addition of rifampin improved the efficacy of vancomycin (decrease, 2.28) and tigecycline (decrease, 1.56) in solitary; there were not significantly differences between tigecycline-rifampin (decrease, 3.39) and vancomycin-rifampin (decrease, 3.70), but only the latter was better than rifampin alone (P < 0.05). Resistant strains were only detected using rifampin alone. CONCLUSIONS:tigecycline alone was the least effective treatment. Tigecycline-rifampin prevented the emergence of rifampin resistance, thus allowing the benefits of rifampin over time against staphylococcal foreign-body infections, but its efficacy needs to be evaluated in comparison with other anti-MRSA combined therapies.
Authors: Y Achermann; K Eigenmann; B Ledergerber; L Derksen; P Rafeiner; M Clauss; R Nüesch; C Zellweger; M Vogt; W Zimmerli Journal: Infection Date: 2012-09-19 Impact factor: 3.553