Safety and efficacy of colistin compared with imipenem in the treatment of ventilator-associated pneumonia: a matched case-control study

Objective: Our study aimed to determine the efficacy and safety of colistin in the treatment of ventilator-associated pneumonia (VAP) caused by pan-drug-resistant Pseudomonas aeruginosa or Acinetobacter baumanii. Design: Pairwise, retrospective exposed-unexposed study. Setting: Combined medical and surgical intensive care unit of Habib Bourguiba University Hospital (Sfax, Tunisia). Patients: Sixty patients with VAP caused by pan-drug-resistant A. baumanii or P. aeruginosa matched to 60 controls with VAP caused by A. baumanii or P. aeruginosa susceptible to imipenem. All patients had normal renal function at the onset of antibiotic therapy. Interventions: Case patients were treated by colistin intravenously and control patients were treated by imipenem intravenously. Measurements and results: Baseline characteristics were similar between the colistin and imipenem groups. The mean duration of antibiotic therapy for VAP was 9.5 +/- 3.8 days (range 5-22 days) with colistin and 8.9 +/- 2.8 days (range 5-20 days) with imipenem (p=0.32). A favorable clinical response to antibiotic therapy for VAP occurred in 45 patients (75%) in the colistin group and in 43 patients (71.7%) in the imipenem group (p=0.68). The time to resolution of infectious parameters after the initiation of antibiotic therapy was not statistically different between the two groups. During the antibiotic course, none of the patients in either group developed renal failure. Conclusions: We conclude that colistin can be a safe and effective option in the treatments of VAP caused by pan-drug-resistant P. aeruginosa or A. baumanii.