Combined therapy with nebulized and intravenous colistin for the treatment of multidrug resistance pneumonia in burn patients: experience from a third referral burn care center in Mexico City

PURPOSE: Nebulized colistin has shown promise in treating ventilator-associated pneumonia (VAP) due to carbapenem-resistant strains; evidence in burn patients is limited. This study evaluated the efficacy of nebulized colistin as an adjunct to intravenous colistin in burn patients with pneumonia caused by multidrug-resistant (MDR) Gram-negative bacteria. MATERIALS AND METHODS: A retrospective cohort was conducted at a burn center in Mexico City (August 2011-May 2017). Patients diagnosed with VAP or hospital-acquired pneumonia (HAP) due to MDR rods, treated during this period with nebulized colistin plus intravenous colistin or intravenous colistin alone, were included. Clinical response and complications were evaluated on days 2, 5, and 10. Thirty-day survival was analyzed using the Kaplan-Meier method. RESULTS: Fifty patients were included; 41 developed VAP and 9 HAP; combined therapy group included 31 patients. Thermal burns predominated, with airway injury in 26%. Among 65 isolates, Acinetobacter baumannii (n = 28) and Pseudomonas aeruginosa (n = 27) were frequent. Combined therapy was associated with higher frequency of acute respiratory distress syndrome events (61% vs. 32%, p = 0.041), vasopressor use (27% vs. 11%, p = 0.010), longer mechanical ventilation (median 27 vs. 10 days, p = 0.005), elevated SOFA scores (median 3 vs. 1, p < 0.001), and prolonged ICU stay (median 42 vs. 26 days, p = 0.025). Bronchospasm occurred in 13% and alveolar hemorrhage in one patient. No difference in 30-day mortality was observed (log-rank p = 0.63). CONCLUSION: Adding nebulized colistin to intravenous therapy did not improve outcomes in burn patients with multidrug-resistant Gram-negative pneumonia. Prospective studies are needed.