1. Department of Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada
2. Bacterial Symbionts Evolution, INRS-Centre Armand-Frappier Santé Biotechnologie, Laval, Quebec H7V 1B7, Canada
3. Department of Animal Science, The Pennsylvania State University, State College, PA 16802-3500, USA
4. McGill International TB Centre, McGill University, Montreal, Quebec H4A 3S5, Canada