The goal of this clinical trial is to compare the clinical efficacy of individualized dosing based on the population pharmacokinetics (PK) model and empirical dosing of vancomycin in participants with severe infections. It aims to answer whether individual vancomycin dosing based on population PK model is superior to empirical dosing in terms of clinical efficacy and safety. Participants will be randomly divided into experimental group and control group. The experimental group will be guided by the population PK model for individual dosing, and the control group will be given empirical dosing. Demographic data, clinical characteristics of participants, and their trough concentrations (Cmin) and peak concentrations (Cmax) of vancomycin will be collected. Area under the concentration curve (AUC24) of participants will be calculated using the first-order PK equation. Researchers will compare experimental group and control group to see if individual vancomycin dosing based on population PK model is superior to empirical dosing in terms of clinical efficacy and safety.