Volume 59, Issue 4, Pages 277-280 (October 2009) Potential therapeutic failure of generic vancomycin in a liver transplant patient with MRSA peritonitis and bacteremia  Carlos A. Rodriguez, Maria Agudelo, Juan C. Cataño, Andres F. Zuluaga, Omar Vesga  Journal of Infection  Volume 59, Issue 4, Pages 277-280 (October 2009) DOI: 10.1016/j.jinf.2009.08.005 Copyright © 2009 The British Infection Society Terms and Conditions

Figure 1 Panel A: population analysis profile (PAP) of S. aureus GRP-0109 (MRSA isolated from the case patient). Right y-axis illustrates the resistance frequency (RF=log10CFU grown in the presence of antibiotic/log10 CFU grown in antibiotic-free medium). All RF at vancomycin concentrations in the VISA (vancomycin-intermediate S. aureus) range (>2mg/L) were <−6.0log10(<1×10−6), ruling out the hVISA phenotype. Panel B: dose-effect relationships against S. aureus GRP-0057 in the neutropenic mouse thigh infection model of the innovator products of penicillin G (blue), oxacillin (red) and vancomycin (black) administered subcutaneously q1h during 24h. Pharmacodynamic parameters maximum effect (Emax) and bacteriostatic dose (BD) were obtained fitting the data to Hill's sigmoid model. The three antibiotics display equal efficacy against S. aureus (no difference in Emax, P=0.51 by ANOVA). Panel C: dose-effect relationships against S. aureus GRP-0057 (a wild-type clinical strain) in the neutropenic mouse thigh infection model of generic (red) and innovator (black) vancomycin administered subcutaneously q1h during 24h. Pharmacodynamic parameters maximum effect (Emax) and bacteriostatic dose (BD) were obtained fitting the data to Hill's sigmoid model by least squares non-linear regression and compared by curve fitting analysis (CFA). Generic vancomycin was more than 1000 times inferior in efficacy compared with the innovator product. Journal of Infection 2009 59, 277-280DOI: (10.1016/j.jinf.2009.08.005) Copyright © 2009 The British Infection Society Terms and Conditions