Pharmacokinetic-pharmacodynamic evaluation of daptomycin, tigecycline, and linezolid versus vancomycin for the treatment of MRSA infections in four western European countries

Purpose To evaluate the usefulness of daptomycin, tigecycline, and linezolid for the treatment of MRSA infection compared with vancomycin in Belgium, the United Kingdom/Ireland, and Spain. Methods The methodology included the following steps: acquisition of microbiological and pharmacokinetic data, Monte Carlo simulation, estimation of the probability of target attainment (PTA), and calculation of the cumulative fraction of response (CFR). Results We showed that differences in the susceptibility of MRSA strains among countries may justify differences in the antibiotic dose selection. Two, 3, and 4 g daily of vancomycin seem be adequate in Belgium, Spain, and United Kingdom/Ireland respectively. The CFR obtained with 50 mg tigecycline every 12 h was higher in Spain than in Belgium and the United Kingdom/Ireland, but with the highest dose (100 mg q12h) the CFR was always 100%. At least 8 mg/kg daptomycin is necessary in United Kingdom/Ireland, but 4 mg/kg may be sufficient in Spain, and probably in Belgium. Six hundred mg q12h linezolid may be adequate in the four countries. Conclusion Our study reinforces the idea that the local MIC distribution must be considered in order to increase the probability of success of empirical treatment and must be periodically updated.