The Role of γ-Aminobutyric Acid Shunt in Cronobacter sakazakii Resistance to Desiccation
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Abstract:
Cronobacter sakazakii is a food-borne pathogen commonly found in powdered infant formula (PIF). γ-aminobutyric acid (GABA) is a non-protein amino acid widely present in various organisms. 4-aminobutyrate transaminase, encoded by gabT, is a key enzyme in the GABA shunt. This study constructed a gabT gene knockout strain (ΔgabT) of Cronobacter sakazakii ATCC 29544 to investigate the effect of the GABA shunt controlled by gabT on the resistance of Cronobacter sakazakii to desiccation. The results showed that the survival rate of ΔgabT under one-week desiccation stress was 28.64 %, significantly higher than that of the wild-type strain (WT) which was 1.57%. In addition, GABA accumulation in ΔgabT was higher than that in WT, and was positively correlated with survival rate, suggesting that GABA accumulation can help Cronobacter sakazakii resist desiccation stress. The results of scanning electron microscopy also showed that the ΔgabT strain had relatively intact cell membrane morphology, further confirming that GABA accumulation contributes to Cronobacter sakazakii survival under the stress of dry environments. This study lays a foundation for the targeted inhibition of Cronobacter sakazakii based on its GABA shunt and provides new directions for research into prevention and control of Cronobacter sakazakii.
