Impact of kdpE gene deletion on virulence and environmental resilience in Cronobacter sakazakii.

Cronobacter sakazakii is a Gram-negative, foodborne pathogen associated with severe infections, particularly in infants and immunocompromised individuals. Given its significant public health implications and its remarkable resilience in powdered infant formula, understanding the genetic factors that contribute to its virulence and environmental tolerance is crucial. This study focuses on the kdpE gene in Cronobacter sakazakii, part of a two-component regulatory system known for its role in adaptation to environmental stress. A kdpE knockout mutant of Cronobacter sakazakii was constructed to evaluate its effects on bacterial growth, virulence, biofilm formation, and desiccation tolerance. The results revealed that kdpE deletion reduced bacterial growth and virulence, as evidenced by higher survival rates in rats infected with the ΔkdpE mutant compared to the wild-type strain. Notably, the ΔkdpE mutant showed significant downregulation of proteins involved in carbon metabolism and respiratory activity, while proteomic analysis revealed increased deamidation of proteins related to glycolysis. Furthermore, biofilm formation was significantly impaired in the mutant, although its desiccation tolerance was enhanced, attributed to the upregulation of the molecular chaperone GrpE. These findings suggest that kdpE plays a crucial role in regulating the virulence and environmental adaptability of Cronobacter sakazakii, with implications for understanding its pathogenic mechanisms and developing preventive measures.