TEM PLUĆA MIŠEVA INFICIRANIH S FRANCISELLA

Francisella tularensis is a highly virulent facultative intracellular bacterium and is considered a potential biological warfare agent. F. tularensis subsp. novicida is attenuated in humans but it causes tularemia in mice that is similar to that caused by subsp. tularensis. The intracellular lifestyle of F. tularensis is unique compared to all other described intracellular pathogens. Our recent studies have shown that IglC protein is required for intracellular replication of the bacteria in macrophages but nothing is known about the role of this protein in the pathogenesis of the disease. Here we examined intracellular replication of wild type strain of F. tularensis subsp. novicida and the iglC mutant in the lungs of BALB/c mice by transmission electron microscopy (TEM). After forming the phagosome F. tularensis subsp. novicida replicated in the lungs of BALB/c mice, and the peak of replication was achieved at 48h after infection. In contrast, the lungs of mice infected with the iglC mutant contained only one or two bacteria per phagosome. Our data show intracellular replication of F. tularensis subsp. novicida in the ultrastructural level and importance of iglC gene in pulmonary infection of BALB/c mice.