Use of Monte Carlo simulation to evaluate the development of vancomycin resistance in meticillin-resistant Staphylococcus aureus

作者:Mei, Qing; Ye, Ying; Zhu, Yu-lin; Cheng, Jun; Yang, Hai-fei; Liu, Yan-yan; Li, Hong-ru; Li, Jia-bin*
来源:International Journal of Antimicrobial Agents, 2015, 45(6): 652-656.
DOI:10.1016/j.ijantimicag.2015.01.018

摘要

Monte Carlo simulations were performed for various vancomycin dosage regimens to evaluate the potential for development of vancomycin resistance in meticillin-resistant Staphylococcus aureus (MRSA). When the target of free AUC(24)/MIC >= 200 was considered (where AUC(24) is the area under the drug concentration-time curve in a 24-h interval and MIC is the minimum inhibitory concentration), a standard dose regimen (1000 mg every 12 h) yielded unacceptable simulated outcomes in patients with normal renal function; in particular, the probability of target attainment (PTA) was only 30.5% at an MIC of 1 mg/L. For the same dosage regimens and the mutant prevention concentration (MPC)-based pharmacokinetic target (total AUC(24)/MPC > 15), the cumulative fraction of response exceeded 80% for all renal function strata; low values of PTA (< 80%) were obtained only for isolates with MPCs of >= 22.4 mg/L, which consisted of all 21 strains of heterogeneous vancomycin-intermediate S. aureus (hVISA) and a handful of non-hVISA strains with MICs of 2 mg/L (32%; 16/50). Based on the current status of vancomycin resistance, we conclude that total AUC(24)/MPC > 15, derived from in vivo experiments, is more suitable to predict the development of vancomycin resistance. In clinical practice, individualised vancomycin therapy should be considered to minimise selection of resistance mutations.