It was found that at low temperature (6-8 degrees C) in the absence of nitrogen supply and at the presence of phosphate ions in the medium, Yersinia pseudotuberculosis and Listeria monocytogenes are able to actively synthesize reserve substances as polyphosphates. Most of the bacterial polyphosphates are alkali-soluble, especially at the preliminary stage of cell growth (lag-phase). This is proved by electron microscopic studies of ultrastructure of model microorganisms. During a long starvation period under conditions of carbon and energy source deficit, L. monocytogenes and Y. pseudotuberculosis consume this biopolymer for biosynthetic and bioenergetic processes.

The biological activity of ethyl acetate extract of exometabolites from the marine microalgae Phaeodactylum tricornutum against a test culture of Listeria monocytogenes 4b has been investigated. It was shown that the stimulating effect of algal exometabolites on the growth of pathogenic bacteria increased max imally by 98.3% on day 6 of the cultivation, if the active substances comprising the culture liquid of P. tricor nutum were separated by successive extractions with solvents in order of increasing polarity (hexane, benzene, ethyl acetate), and by 150% on day 3, if the substances from the ethyl acetate extract of exometabolites were separated by column chromatography. It is noted that the fraction of biologically active substances maximally stimulating the growth of L. monocytogenes can be used to prepare an accumulation medium for detecting these pathogenic bacteria in marine environments and hydrobionts.

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This review presented the problem of saprozoonoses survivability in the marine environment. It is shown that hydrobionts is one of the major infection transmission factors. But the marine environment is unfavorable for existence of pathogenic bacteria; therefore, one of the important issues is mechanisms disclosure allowing to explain the continued existence of pathogenic bacteria in the marine environment. Experimental studies on aquatic organisms, reflecting the coping mechanisms of pathogenic bacteria in the marine environment have been discussed. Information concerning processes of marine bacteria biofilm formation has been stated. It is shown that biofilms can be formed by bacteria of one type or form a community of developing from many species of microorganisms, such as bacteria, protozoa, fungi or algae. It is noted that in the natural habitats biofilms can cause serious environmental deterioration, since they are difficult to destroy. The literature review showed that the pathogenic bacteria survivability in the marine environment is possible due to development of a wide range of different hosts (microalgae, plants, mollusks, protozoans, crustaceans, etc.), as well as due to the formation of biofilms as mono- and mixed options on various surfaces, contributing to the preservation of their viability.

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