Growth of Francisella spp. in rodent macrophages

Abstract

We examined the nature of the interactions between the facultative intracellular pathogens Francisella tularensis and F. novicida and rodent macrophages. Growth of F. tularensis LVS was observed in macrophage monolayers from mice, guinea pigs, or rats. In contrast, F. novicida grew in macrophages from mice and guinea pigs but not in macrophages from rats. Transmission electron microscopy studies indicated that both Francisella species survive within macrophage phagosomes that are unfused with lysosomes.