Effect of environmental stress factors on the expression of virulence genes and pathogenicity of lethal of bovine origin.

Objective: () can be used as a probiotic or produce a variety of toxins that are pathogenic to humans and animals. Environmental stressors can affect the growth process of and the expression of its virulence genes. Due to the limitations of methods such as pharmacological disinfection methods (there are limits to the use of antibiotics) and chemical disinfection methods (chemical methods may produce residues), attempts can be made to remove and reduce infections through environmental stress factors.

Methods: In this study, the expression of four virulence genes (, , , and ) of bovine-origin lethal was investigated by qPCR under the effect of different environmental stressors. The extent of pathological damage to various organs of mice by was observed by pathological sections.

Results: The results showed that high temperature could inhibit the expression of virulence genes. Expression of virulence genes was affected under the influence of pH. Different salt concentrations could make the virulence genes show low expression. Under a single environmental stressors, , , , and had the lowest expression at 40°C, pH 8.0, and were lowly expressed at all salt concentrations except the control group. The action of multiple environmental stressors affect the expression of virulence genes. Under multiple environmental stressors, , and were least expressed at a temperature of 40°C, pH 6.0, and salt concentration of 3.0%, and was least expressed at a temperature of 20°C, pH 8.0, and salt concentration of 1.5%. Animal pathogenicity tests have shown that environmental stressors affect the virulence of .

Conclusion: The level of virulence gene expression in can be reduced by environmental stress factors, thus further reducing the risk of to human health. This study provides some reference for the prevention and control of disease.