In vitro bactericidal activity of daptomycin versus vancomycin Cmax concentrations in the presence of human albumin physiological concentrations against vancomycin-susceptible but tolerant methicillin-resistant Staphylococcus aureus
Abstract number: P1988
Torrico M., Aguilar L., Gonzalez N., Gimenez M.J., Cafini F., Alou L., Sevillano D., Cleeland R., Prieto J.
Objective: To study the antibacterial activity (log10 reduction) and time to obtain bactericidal activity (time to obtain 3 log10 99.9% initial inocula reduction, T99.9%) in the presence of physiological concentrations of human albumin by concentrations similar to Cmax obtained in serum with 6 mg/kg od daptomycin and 1g bid vancomycin regimens, against vancomycin-susceptible but tolerant methicillin-resistant Staphylococcus aureus (MRSA).
Methods: Killing curves were performed with final inocula of approx. 107 cfu/ml, and a final concentration of 98.6 mg/l daptomycin or 65.7 mg/l vancomycin, using as media Mueller-Hinton broth (Cmax-MH) and MH broth with 4 g/dl human albumin (Cmax-HAlb). In the case of daptomycin, media were supplemented with Ca2+ (by adding 100 mg/l of Ca2+ in media containing albumin and 50 mg/l in media without albumin) in order to obtain a physiological free Ca2+ concentration.
Results: MIC/MBC (mg/l) of daptomycin and vancomycin, T99.9% (h) and log10 initial inocula reduction at 12 h/24 h are shown in the Tables.
Conclusions: Daptomycin Cmax exhibited rapid (3 h) bactericidal activity while vancomycin did not achieve bactericidal activity along 24 h against vancomycin-susceptible but tolerant MRSA. The presence of human albumin physiological concentrations slightly delayed T99.9% for daptomycin.
|Session name:||19th European Congress of Clinical Microbiology and Infectious Diseases|
|Location:||Helsinki, Finland, 16 - 19 May 2009|
|Back to top|