Rifampicin as Adjunct to Colistin Therapy in the Treatment of Multidrug-Resistant Acinetobacter baumannii

Objective: To evaluate the available evidence regarding the efficacy and safety of rifampicin, as adjunct to colistin, in the treatment of multidrug resistant Acinetobacter baumannii (MDR-AB). Data Sources: We searched MEDLINE (1966 to January 2014) using the following search terms: A baumannii, drug resistance, treatment, colistin, and rifampicin and combinations. In addition, the bibliographies of relevant articles were searched for additional citations. Study Selection and Data Extraction: The search was limited to English-language references and adults. Studies in which colistin was not administered intravenously were excluded. In addition, we excluded meeting abstracts and single case reports. Data Synthesis: The search strategy identified 5 observational studies and 2 randomized controlled trials that evaluated the combination of intravenous colistin and rifampicin for the treatment of MDR-AB. All observational studies included a small sample size, and the microbiological clearance associated with the combination therapy ranged from 60% to 100%. The randomized controlled trials reported reduced time to microbiological clearance and higher microbiological eradication rate in the colistin/rifampicin group compared with colistin alone. However, there was no difference between both groups in the overall mortality, infection-related mortality, and the length of stay. Furthermore, rifampicin was associated with a higher incidence of hepatotoxicity. Conclusions: Studies evaluating the combination of rifampicin and colistin in the treatment of MDR-AB are limited. The currently available evidence does not support the addition of rifampicin to colistin because of the lack of improved clinical outcomes with the combination therapy and the risk of rifampicin-induced hepatotoxicity.