Intravenous colistin as therapy for nosocomial infections caused by multidrug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii

Sixty nosocomial infections caused by Pseudomonas aeruginosa and Acinetobac ter baumannii resistant to aminoglycosides, cephalosporins, quinolones, pen icillins, monobactams, and imipenem were treated with colistin (one patient had two infections that are included as two different cases). The infectio ns were pneumonia (33% of patients), urinary tract infection (20%) primary bloodstream infection (15%), central nervous system infection (8%), periton itis (7%), catheter-related infection (7%), and otitis media (2%). A good o utcome occurred for 35 patients (58%), and three patients died within the f irst 48 hours of treatment. The poorest results were observed in cases of p neumonia: only five (25%) of 20 had a good outcome. A good outcome occurred for four of five patients with central nervous system infections, although no intrathecal treatment was given. The main adverse effect of treatment w as renal failure; 27% of patients with initially normal renal function had renal failure, and renal function worsened in 58% of patients with abnormal baseline creatinine levels. Colistin may be a good therapeutic option for the treatment of severe infections caused by multidrug-resistant P. aerugin osa and A. baumannii.