Abstract
Colistin, as one of the last treatment options for multidrug-resistant Gram-negative infections, is limited by nephrotoxicity. Previous studies report inconsistent Colistin-Induced Nephrotoxicity (CIN) incidence rates (20-50%) due to varied definitions of acute kidney injury (AKI) and patient characteristics. This study aims to determine CIN incidence and risk factors in patients with Blood Culture-Positive Multidrug-resistant Gram-negative bacteremia at a center in a high-resistance region in Iran. This cross-sectional study analyzed 124 adults receiving ≥ 48 hours of colistin (April 2021–April 2022) at a tertiary hospital. CIN was defined using RIFLE criteria. Variables included demographics, treatment duration, renal function, comorbidities, and concurrent medications. Statistical analyses used SPSS v26, with significance at p 10 days; p = 0.007) and higher baseline serum creatinine (1.68 vs. 1.28 mg/dL; p = 0.042) were significant risk factors. Dose-dependent nephrotoxicity was observed in patients with estimated glomerular filtration rate (eGFR) < 50 mL/min/1.73 m² (p = 0.023). No significant associations were observed with age, gender, comorbidities, N-acetylcysteine, concurrent nephrotoxic medications, or pathogen types. Individualized dosing and renal function monitoring are critical, especially in prolonged therapy. Prospective studies are needed to optimize colistin safety in resistance-prone settings and refine dosing guidelines to ensure treatment success while reducing antibiotic resistance.