engleski

Intracellular survival of Francisella tularensis in Acanthamoeba castellanii

Francisella tularensis is a gram-negative facultative intracellular bacterium that can cause a fatal disease, tularemia, in human and animals. This organism has been isolated from over 250 wildlife species, including fish, birds, amphibians, rabbits, squirrels, hares, voles, ticks, and flies. It resists harsh environments, and has been shown to survive in water and mud for more than a year. The natural reservoirs in water are protozoa including many species of amoeba. Previous results have shown survival and growth of F. tularensis LVS strain in Acanthamoeba castellani. There are no evidence of intracellular survival and growth of F. tularensis subsp. novicida in A. castellanii. In addition, the role of iglD, iglC and mglA genes of F. tularensis in A. castellanii survival and growth are unknown. Our results showed that F. tularensis survive and replicates in A. castellanii. with the peak of replication at 24 h post infection. In contrast, the iglD, iglC and mglA mutant strains of F. tularensis subsp. novicida were completely defective in intracellular replication. We can conclude that F. tularensis subsp. novicida is also connected with natural water system and that A. castellanii plays an important role in survival of the bacteria in nature. For the first time we showed that iglD, iglC and mglA genes of F. tularensis subsp. novicida are crucial for their survival and intracellular replication in A. castellanii.

Francisella; Acanthamoeba; mutants

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