Przeżywalność bakterii Salmonella Enteritidis w wodach powierzchniowych

The most frequent cause of salmonelloses are food poisonings. However, many studies prove the occurrence and possibility of survival of rods of the genus Salmonella in lakes. The bacteria are often isolated from water sources, which act as a bacterial reservoir. Rods of Salmonella are constantly released to the environment, which results in infections of people and animals. In comparison with other microorganisms, bacteria of the genus Salmonella are characterized by a high survival rate in water environments, particularly in waters of highly eutrophicated lakes. Temperature, the shortage of nutrients, osmotic stress and light has the most negative effect on their survival. Due to its common accessibility, water is an environment which plays an essential role in spread of diseases. The aim of this study was to estimate the effect of selected temperatures on the survival rate of bacilli Salmonella Enteritidis, and the dynamics of quantitative changes of the bacteria in time in bathing waters used for recreation, tested under laboratory conditions. As well as to determine the dynamic of quantitative changes of the bacteria in time under laboratory conditions. The samples for the study were collected from a lake in the Bydgoszcz district. In the conducted experiment it was indicated that Salmonella Enteritidis survived longer in water at 4°C (51 days), as compared with 20°C (39 days). In the present study the elimination rate of bacteria population, according to the analysis of regression, amounted to 0.16 log daily at 4°C, whereas at 20°C it assumed a value of 0.15 log daily. Consequently, it may be concluded that a lower temperature has a more stabilizing effect on rods of the genus Salmonella.