Efficacy and Safety of Colistin (colistimethate Sodium) for Therapy of Infections Caused by Multidrug-resistant Pseudomonas Aeruginosa and Acinetobacter Baumannii in Siriraj Hospital, Bangkok, Thailand

Objective: To determine the efficacy and safety of colistin (colistimethate sodium) produced by a local pharmaceutical company in Thailand for the treatment of infections caused by multidrug-resistant (MDR) Pseudomonas aeruginosa and Acinetobacter baumannii.

Methods: Patients hospitalized at Siriraj Hospital between January 2005 and April 2006, who had infections caused by MDR P. aeruginosa or A. baumannii, were enrolled in the study. Colistin (colistimethate sodium) at a dosage of 5 mg/kg/day was given intravenously in two divided doses. Primary outcomes were the clinical response and 30-day mortality; secondary outcomes were microbiological response and adverse events.

Results: Ninety-three patients infected with MDR P. aeruginosa and A. baumannii were enrolled. Seventy-eight patients (71 with A. baumannii and seven with P. aeruginosa) received colistin, whereas 15 patients (12 with A. baumannii and three with P. aeruginosa) received other antibiotics. The mean age, gender, underlying conditions and severity of illness of the patients in both groups were not significantly different. In the colistin group, 63 patients (80.8%) had a favorable clinical response and 94.9% had a microbiological response. The overall mortality of the patients in the colistin group was 46.2% and that in the non-colistin group was 80%. Nephrotoxicity was found in 24 patients (30.8%) in the colistin group and 17 of them had predisposing factors contributing to their renal dysfunction. No neurotoxicity was observed among the 78 patients.

Conclusion: Locally produced colistin appears to be safe and effective for the treatment of infections caused by MDR P. aeruginosa and A. baumannii in Thai adult patients.