What are Frank pathogens?

Francisella are Gram-negative, facultative intracellular bacteria and the sole genus in the family, Francisellaceae. Members of this genus are found both in nature and as pathogens in mammals. The five pathogens are Francisella tularensis, Francisella novicida, Francisella philomiragia, Francisella hispaniensis, and Francisella noatunensis.