Walsh & Hoyt: Francisella tularensis

In 1911, McCoy described a ""plague-like disease of rodents"" in California. In the following year, he and Chapin recovered the causative organism from rodents in Tulare County, California, naming it Bacterium tularense. The name of this bacterium was changed on several occasions. It was finally called Francisella tularensis in honor of Dr. Edward Francis, the investigator who conducted some of the earliest clinical and laboratory studies of tularemia. F. tularensis is a small, nonmotile, gram-negative coccobacillus that tends to be pleomorphic in culture. The organism seems to have many antigenic components, including a polysaccharide antigen, a protein antigen that cross-reacts with Brucella, and an endotoxin similar to those produced by other gram-negative bacteria.