The phenomenon of <Emphasis Type="Italic">Yersinia pestis</Emphasis> biofilm formation in the organism of fleas

The paper considers, for the first time, the formation of the extracellular matrix envelope (EME), or the biofilm, by Yersinia pestis as the basis determining the nature of interaction of the plague agent with the flea organism. The significance of the insect proventriculus in the process of biofilm formation is shown. The ultrastructure of the conglomerates of the plague microbe in the flea proventriculus and midgut was studied and the uniform mechanism of their formation was established. The role of Yersinia pestis biofilm in preservation of the plague microbe in the intestine of ectoparasites and in the soil of rodent burrows was discussed. PCR analysis confirmed the presence of the agent in plague infected corpses and flea feces stored at +8−10°C for 7 years and 9 months.