Objective: To assess the efficacy and toxicity of intravenous colistin in the treatment of infections due to multidrug-resistant gram-negative bacteria.
Methods: Retrospective cohort study.
Results: Sixty patients received colistin sulphomethate sodium (mean dose, 4.4mg/kg/day; median duration, 20days). The main infections were pneumonia or tracheobronchitis (63.3%), intra-abdominal (10%), urinary tract (8.3%), and surgical site infection (6.6%), primary bacteremia (5%), catheter infection (3.3%), meningitis (1.6%), and soft-tissue infection (1.6%). The responsible bacteria were Acinetobacter spp. (50%), P. aeruginosa (23.3%), K. pneumoniae (13.3%), Enterobacter spp. (10%), E. coli (1.6%), and S. maltophilia (1.6%). Eight patients (13%) received colistin monotherapy, and 52 (87%) received combination therapy with other antibiotics such as beta-lactams (15 cases), aminoglycosides (14), beta-lactams and aminoglycosides (15), or ciprofloxacin (8). A favourable response was observed in 43 cases (71.7%). Overall mortality was 26.7%. Despite the common use of combination therapy with aminoglycosides (48%), nephrotoxicity during colistin therapy was observed in only 10.9% of patients; most of them had previous renal failure.
Conclusion: Colistin appears to be an effective and safe drug for therapy of severe infections due to multidrug-resistant gram-negative bacteria. Despite the concomitant use of aminoglycosides in a high proportion of patients, renal toxicity was an uncommon adverse event.