Abstract: AIM: To discuss the application and clinical significance of the ratio of area under the curve over 24 hours to minimum inhibitory concentration (AUC24h/MIC) as the monitoring target of vancomycin in patients with severe infections of multi drug resistant gram positive bacteria (MDR G+bacteria) in our hospital.  METHODS: All patients with MDR G+bacterial infections were performed serum trough concentration of vancomycin (Ct). We used the pharmacokinetic software JPKD and Bayesian calculation to estimate the AUC24h/MIC of vancomycin (if MIC=1 mg/L). Then we compared the attainment rates of AUC24h/MIC with different Ct range, and tried to find out the probable interfering factors that might affect AUC24h/MIC and the clinical significance to take AUC24h/MIC as a predictor of curative effect and nephrotoxicity. RESULTS: Multiple linear regression analysis showed Ct had a good correlation with AUC24h/MIC. When Ct was 10-15 μg/mL, only 38.89% of the patients performed AUC24h/MIC 400-600, but when Ct was 15-20 μg/mL, up to 88.89% of the patients could achieve the recommended range. The curative effect of vancomycin seemed to have a significant correlation with patients accepting intensive care or not, rather than AUC24h/MIC. Whether use Ct＞20 μg/mL or AUC24h/MIC＞600 as an indicator to evaluate the occurrence risk of acute kidney injury(AKI) showed no differences. CONCLUSION: Patients with MDR G+bacterial infections should maintain Ct between 15-20 μg/mL, in this case, there was 88.89% probability to achieve AUC24h/MIC of 400-600. Also, the standardized testing of MIC should be proposed to improve the clinical application of vancomycin.

Key words: vancomycin, trough concentration, AUC24h/MIC, MDR gram positive bacterial infections