Increasing antibiotic resistance in bacteria of clinical relevance is threatening our ability to treat bacterial infections. Though commensal (normal) bacteria are suspected reservoirs of antibiotic resistance genes, little is known about the abundance, diversity, and distribution of resistance genes in commensal bacteria. The cross-species transfer of such genes from commensal to pathogenic bacteria, though supported by a growing body of scientific evidence, is equally poorly understood. Numerous mechanisms of horizontal gene transfer suggest that the frequency of resistance genes in commensals may act as a marker of the emergence of resistance in pathogens.

The Reservoirs of Antibiotic Resistance (ROAR) project, coordinated by the Alliance for the Prudent Use of Antibiotics and currently funded by a 5-year grant from the National Institute of Allergy and Infectious Diseases, is an unprecedented effort to improve scientific understanding of the role of commensal bacteria in the spread of antimicrobial resistance. This is approached by 1) compiling existing commensal isolate data and literature into a Web-based bioinformatics tool; 2) using statistical, risk analysis, and mathematical modeling techniques to analyze the data in order to determine if the frequency of antibiotic resistance genes in commensals can predict the subsequent emergence of antibiotic resistance in pathogenic bacterial populations and 3) encouraging, directing, and funding research efforts to evaluate antibiotic resistance in commensals. ROAR has awarded ten research sub-grants since 1997.