RecA deletion disrupts protein homeostasis, leading to deamidation, oxidation, and impaired glycolysis in Cronobacter sakazakii.

Cronobacter sakazakii is a foodborne pathogen linked to severe infections in infants and often associated with contaminated powdered infant formula. The RecA protein, a key player in DNA repair and recombination, also influences bacterial resilience and virulence. This study investigated the impact of recA deletion on the pathogenicity and environmental stress tolerance of C. sakazakii BAA-894. A recA knockout mutant displayed impaired growth, desiccation tolerance, and biofilm formation. In a rat model, the mutant demonstrated significantly reduced virulence evidenced by higher host survival rates and lower bacterial loads in blood and tissues compared to the wild-type strain. Proteomic analysis revealed extensive disruptions in protein expression, particularly downregulation of carbohydrate metabolism and respiration-related proteins, alongside increased protein deamidation and oxidation. Functional assays identified fructose-bisphosphate aldolase as a target of oxidative and deamidative damage, resulting in reduced enzymatic activity and glycolytic disruption. These findings highlight the critical role of RecA in maintaining protein homeostasis, environmental resilience, and pathogenicity in C. sakazakii, providing valuable insights for developing targeted interventions against this pathogen.IMPORTANCECronobacter sakazakii poses significant risks due to its ability to persist in low-moisture environments and cause severe neonatal infections. This study identifies RecA as a key factor in environmental resilience and virulence, making it a promising target for mitigating infections and contamination. Inhibiting RecA function could sensitize C. sakazakii to stress during production and sterilization processes, reducing its persistence in powdered infant formula. Future research on RecA-specific inhibitors may lead to innovative strategies for enhancing food safety and preventing infections caused by this pathogen.