This photograph depicts the colonial morphology displayed by Gram-negative Francisella tularensis bacteria, which was grown on a medium of modified Thayer-Martin (MTM) agar, for a 72 hour time period, at a temperature of 37�C. Take a look at PHIL 12444 and 12445, which depict the appearance of F. tularensis colonies grown on the same medium, and at the same temperature, but for one-third the time (24hr). Also see PHIL 12446, for the appearance of bacterial colonies, again, grown on the same medium, and at the same temperature, but also, for a lesser time period (48hr). This bacterium is both an animal, and a human pathogen, and is responsible for causing the disease known as tularemia.
CDC/ Amanda Moore, MT; Todd Parker, PhD; Audra Marsh
December 4, 2012