2007). ftnA and bfr single and double mutants had no phenotype, yet a ftnA, bfr, ftnB triple mutant was more attenuated than the ftnB mutant alone, indicating that FtnA and Bfr may indeed play a role during infection (Velayudhan et al. 2007). This same study also investigated the role of fur, demonstrating the fur mutants were completely avirulent (Velayudhan et al. 2007). The gene discussed is FURIN; the disease is infection.