Combined microbiological and clinical outcomes of short-term inhaled colistin adjunctive therapy in ventilator-associated pneumonia

Abstract

Purpose Aerosolized antibiotics have potential lower risks of toxicity. Colistin has an excellent bactericidal activity against most gram-negative bacilli. We aimed to define both microbiological and clinical target outcomes after a 5-day treatment period in the treatment of patients with gram-negative ventilator-associated pneumonia (VAP). Patients and methods We recruited all patients with gram-negative bacteria culture and sensitivity taken from endotracheal tube aspirates after greater than or equal to 48 h of mechanical ventilation and clinical pulmonary infection score (CPIS) greater than or equal to 6. Patients were randomized to enter either the study group of inhaled colistin (3 million IU/day, for 5 days) as an adjunctive therapy to intravenous antibiotic treatment of VAP or enter the control group of intravenous antibiotics only. In both arms, intravenous antibiotics were started from the day of clinical suspicion according to American Thoracic Society/Infectious Disease Society of America guidelines. Interpretations on day 6 included microbiological outcome (endotracheal tube aspirate culture and sensitivity) and CPIS. Favorable outcome was defined if there was a microbiological clearance and CPIS less than 6. Patients were monitored for bronchospasm, daily serum creatinine, days of mechanical ventilation, and 30-day mortality. Results A total of 102 patients were recruited. Colistin group included 52 patients and the control group included 50 patients. Favorable outcome was higher [41 (78.8%) vs. 27 (54%), P=0.02] in colistin versus control group, respectively. Prolonged mechanical ventilation for more than 15 days was lower [23 (44.2%) vs. 44 (88%), P=0.01] and a 30-day hospital mortality was lower [21/52 (40.3%) vs. 35/50 (70%), P=0.008] in colistin versus control group, respectively. Conclusion Five days of adjunctive inhaled colistin in patients with gram-negative VAP showed a higher combined clearance and clinical improvement, including multidrug resistant groups, decreased duration of mechanical ventilation, and ICU mortality when compared with conventional intravenous therapy alone