Sidorenko M. L., Buzoleva L. S.
В издании Listeria monocytogenes^ food sources, prevalence and management strategies
Год: 2014 Страницы: 231-264
Soil is one of the ecological niches of L. monocytogenes, where these bacteria are equal members of the microbial community, although the mechanisms of their adaptation and forms of existence in soil ecosystems are studied insufficiently. Up to now, scientists considered the in?uence of soil on the reproduction of L. monocytogenes without regard for the soil genesis and soil chemical and physical properties. It is obvious that the type of soil and different soil properties play a certain part in the reproduction of pathogenic microorganisms, because soils differ sharply in their humus content, concentrations of nutrients, pH, particle-size composition, and microbial associations. Of course, in such a complex system as the soil processes reproduction of L. monocytogenes can not depend on the action of only one factor. Dynamics of microorganisms is a process caused on the one hand, microbial relationship soil (control factors) on the other hand the properties of the soil and the effect of dynamic factors such as temperature, humidity, nutrient availability. The total effect of the dynamic and regulatory factors determines the changes occurring in the soil microorganism populations. But, nevertheless, to study the influence of individual factors on the L. monocytogenes in soil is important because it facilitates the identification of a mechanism of this phenomenon. Research in this area will identify the patterns of distribution of L. monocytogenes in soils of different material composition and having different physical and chemical properties. In this relation, the physical and chemical properties of brown forest, brown podzolic, tidal marsh, maritime meadow and urban soils that affect the reproduction of L. monocytogenes were studied. The results of the experiments suggest that a high content of exchangeable bases, domination of the fraction of humic acids bound with clay minerals and the fraction of fulvic acids in humus, and high soil temperature stimulate the reproduction of the studied bacteria in soils. A high humus content, a predominance of humates, and a low soil temperature have an inhibiting effect on bacteria. Infiuence of mineral Fertilizers on the reproduction of L. monocytogenes in soil ecosystems under different temperatures (4-60C and 20-220C) were studied. Application of the fertilizers favored preservation and active reproduction of L. monocytogenes in brown podzolic and brown forest soils. Duration of application of the mineral fertilizers positively correlated with preservation and reproduction of L. monocytogenes in different types of soil. The biological activity of volatile metabolites of volatile metabolites of saprophytic soil bacteria and germinating seeds of plant against L. monocytogenes was studied. It was shown that volatile metabolites are transfer factors and can be the sole carbon and energy source for L. monocytogenes. Different character of interspecific relationships between bacteria, influencing their propagation, can be observed on the metabolic level. Volatile compounds produced by microorganisms are capable to act as both intra- and interspecific regulators of microbial communities. In this connection the propagation of L. monocytogenes inhabiting soil may be stimulated or inhibited by the metabolic products of soil microorganisms. Methanol is the main substance affecting their growth and reproduction.
