| Summary: | Optimal early vancomycin target exposure remains controversial. To clarify the therapeutic exposure range, we investigated the association between vancomycin exposure and treatment outcomes or nephrotoxicity in patients with methicillin-resistant <i>Staphylococcus aureus</i> (MRSA) infection. This retrospective study reviewed clinical data obtained from 131 patients with MRSA infections between January 2017 and September 2019. Clinical outcomes included treatment failure, 30-day mortality, microbiological failure, and acute kidney injury. We measured serum vancomycin levels after the first dose to 48 h and estimated vancomycin exposure using the Bayesian theorem. The minimum inhibitory concentration (MIC) of antimicrobial agents was determined using the broth microdilution method. Classification and Regression Tree analyses identified day 1 and 2 exposure thresholds associated with an increased risk of failure and nephrotoxicity. Treatment failure (27.9% vs. 33.3%) and 30-day mortality (26.6% vs. 31.74%) were numerically but not significantly reduced in patients with the area under the curve (AUC)<sub>24–48h</sub>/MIC<sub>BMD</sub> ≥ 698. Patients with AUC<sub>ss</sub>/MIC<sub>BMD</sub> ≥ 679 exhibited a significantly increased risk of acute kidney injury (27.9% vs. 10.9%, <i>p</i> = 0.041). These findings indicate that AUC<sub>ss</sub>/MIC<sub>BMD</sub> ratios > 600 may cause nephrotoxicity. AUC/MIC<sub>BMD</sub> at days 1 and 2 do not appear to be significantly associated with particular clinical outcomes, but further studies are needed.
|
|---|
