Clinical Profile and Therapeutic Outcomes of Colistin Treatment in Patients Infected with Multidrug-resistant Pathogens: An Observational Study

BACKGROUND: Multidrug-resistant (MDR) Gram-negative infections pose a critical threat in intensive care units (ICUs) due to limited therapeutic options. Colistimethate sodium (colistin), a polymyxin antibiotic, is often used as a last-resort treatment despite concerns about its efficacy and safety. OBJECTIVES: To evaluate the clinical profile and outcomes of patients receiving intravenous colistin for MDR Gram-negative infections in the Medical ICU (MICU) of a tertiary care hospital in Northern India. DESIGN: Prospective observational cohort study. SETTINGS: This study was conducted in the MICU at a tertiary care hospital. MATERIALS AND METHODS: Adult patients (≥18 years) administered intravenous colistin were included. Demographic data, severity scores (acute physiology and chronic health evaluation [APACHE] II, quick sequential organ failure assessment [qSOFA]), infection site, microbiological profile, and treatment details were recorded. Clinical success was defined as clinical improvement followed by discharge in a stable hemodynamic state. MAIN OUTCOME MEASURES: Clinical success rate and overall mortality. SAMPLE SIZE: Fifty patients were included. RESULTS: The median age was 54.24 years. Bloodstream infections were most common (54%), predominantly due to Acinetobacter baumannii (50%), followed by Klebsiella pneumoniae and Pseudomonas aeruginosa. Colistin was used as monotherapy in 68% of patients, yielding a clinical success rate of 64%. Mortality occurred in 36% of patients, mainly those with higher APACHE II and qSOFA scores. CONCLUSIONS: Colistin demonstrated moderate clinical efficacy in critically ill patients with MDR Gram-negative infections. It remains a valuable salvage therapy; however, judicious use and further research are essential to enhance efficacy and minimize resistance and toxicity. LIMITATIONS: Single-center design and small sample size limit generalizability. Nephrotoxicity and pharmacokinetic parameters were not assessed.