Colistin vs. the combination of colistin and rifampicin for the treatment of carbapenem-resistant Acinetobacter baumannii ventilator-associated pneumonia

The aim of this study was to compare the responses of colistin treatment alone vs. a combination of colistin and rifampicin in the treatment of ventilator-associated pneumonia (VAP) caused by a carbapenem-resistant A. baumannii strain. Forty-three patients were randomly assigned to one of two treatment groups. Although clinical (P=0.654), laboratory (P=0.645), radiological (P=0.290) and microbiological (P=0.597) response rates were better in the combination group, these differences were not significant. However, time to microbiological clearance (3.1+/-0.5 days, P=0.029) was significantly shorter in the combination group. The VAP-related mortality rates were 63.6% (14/22) and 38.1% (8/21) for the colistin and the combination groups (P=0.171), respectively. Our results suggest that the combination of colistin with rifampicin may improve clinical and microbiological outcomes of VAP patients infected with A. baumannii.