Rifamycin Antibiotics for Treatment of Clostridium difficile–Associated Diarrhea

Abstract

Objective: To review the existing data on use of the rifamycin class of antibiotics as therapy for Clostridium difficile–associated diarrhea (CDAD). Data Sources: A literature search was performed using PubMed (1996–January 2008), abstracts from the International Conference on Antimicrobial Agents and Chemotherapy (September 2007), the Infectious Diseases Society of America (October 2007), Salix Pharmaceuticals Web site (January 2008), ActivBiotics Web site (January 2008). Google Scholar, and searches of selected bibliographies using the terms rifamycin, ansamycins, rifampin, rifabutin, rifampicin, rifaximin, rifalazil, Clostridium difficile, C. difficile, and CDAD. Study Selection and Data Extraction: In vivo and in vitro studies investigating the use of rifamycins for CDAD were selected, along with all clinical trials using rifamycins in patients with CDAD. Data Synthesis: Nine studies totaling 890 isolates were identified that investigated the in vitro susceptibility of rifampin (6 studies), rifaximin (3 studies), and rifalazil (2 studies). Rifamycins consistently displayed potent activity against tested strains, although strains with decreased susceptibility have been identified. Six published clinical studies involving 81 patients have investigated the use of rifamycins for the treatment of CDAD. These have generally been small studies, although initial positive clinical results have been reported on the use of rifamycins for recurrent CDAD. Conclusions: Preliminary data support the use of rifamycins for treatment of CDAD. With the increased incidence and severity of CDAD, further investigation into this drug class as a treatment regimen for CDAD is warranted.