This study aimed to evaluate whether trough level-guided monitoring can be replaced by area under the concentration-time curve (AUC) and MIC ratio-guided monitoring (AUC/MIC ratio = 400) in patients infected with methicillin-resistant Staphylococcus aureus (MRSA) with a vancomycin MIC = 1 mg/L in Taiwan. In this retrospective study, patients treated with vancomycin for Methicillin-resistant Staphylococcus aureus (MRSA) infection were recruited from a teaching hospital in Taiwan from January 2016 to December 2017. Average trough concentrations were adjusted based on the average daily vancomycin dose, and the AUC/MIC ratio was calculated using the AUC/MIC conversion formula to analyze the correlation between trough or AUC/MIC ratio, nephrotoxicity, and clinical efficacy. As the primary outcome, the overall mean adjusted vancomycin average AUC/MIC ratio was 526.87 for a total of 102 patients. A total of 67% and 76% of the patients attained an AUC/MIC of ≥400 when the adjusted vancomycin trough concentrations were 10 to 15 mg/L and 15 to 20 mg/L, respectively. Additionally, 81.37% of the total study population had MRSA isolates with a vancomycin MIC of ≤1 mg/L. Moreover, in the subgroup, 92% of the patients attained an AUC/MIC of ≥400 on receiving vancomycin in the 10 to 15 mg/L trough range. An AUC/MIC of ≥400 was attained in patients infected with MRSA strains, who were treated by maintaining the vancomycin trough concentrations at 10 to 15 mg/L. Moreover, these patients demonstrated a lower incidence of nephrotoxicity. These findings support the use of the AUC/MIC ratio as a useful marker for the therapeutic monitoring of vancomycin owing to the clinical efficacy and safety of vancomycin in Taiwan. IMPORTANCE Since 2020, the Infectious Diseases Society of America (IDSA) updated vancomycin guidelines, and vancomycin AUC therapeutic drug monitor was updated to AUC/MIC in the United States. But acceptable rate of infection physicians in Taiwan was low. That is why this study evaluated in Taiwan.
Keywords: acute kidney injury (AKI); area under the concentration–time curve (AUC); methicillin-resistant Staphylococcus aureus (MRSA); minimum inhibitory concentration (MIC); pharmacodynamics; therapeutic drug monitoring (TDM); vancomycin.