This study addresses the clinical problem that reliance on serum creatinine, eGFR or empirical dosing fails to accurately adjust anti-infective doses given rapid renal function shifts within the very early 0-5 days post kidney transplantation. We will systematically analyze dynamic trajectories of renal biomarkers (serum creatinine, cystatin C, urine output and other renal function indices), quantify their quantitative associations with the exposure, clearance and pharmacodynamic target attainment of anti-infectives. Combined with clinical profiles, medication data, TDM results and perioperative factors, a population PK/PD model will be built for patients in the very early post-transplant stage. We will further validate the value of dynamic renal markers for individualized anti-infective dosing. This research provides evidence for shifting from static renal function-based empirical dosing to precision dosing guided by real-time renal changes and drug exposure, supporting optimized anti-infective dosage, enhanced efficacy and medication safety in early kidney transplant recipients.