Amino acid decarboxylase-dependent acid tolerance, selected phenotypic, and virulence gene expression responses of Salmonella enterica serovar Heidelberg

作者：Liu, Jiamei; Zhai, Ligong; Lu, Wenjun; Lu, Zhaoxin; Bie, Xiaomei^*

来源：Food Research International, 2017, 92: 33-39.

DOI：10.1016/j.foodres.2016.12.006

• Salmonella Heidelberg
• Acid tolerance response
• Amino acid decarboxylase
• Phenotype
• Virulence

Salmonella enterica serovar Heidelberg (S. Heidelberg) is one of the pathogens most frequently detected in recent years in food products from animals; here, we examine the acid tolerance of this strain. Mild acid (pH 5.5-5.0) induced a strong acid resistance in S. Heidelberg; the induced acid resistance improved within 0.5-6 h and resulted in >95% cell survival following challenge in pH 3.0 Medium. Addition of lysine or arginine to pH 2.5 acid challenge medium significantly improved the survival of S. Heidelberg; lysine induced the largest increase in survival. The lysine and arginine decarboxylase-related genes (i.e., cadA, cadB, adiA, arid adiY) are acid induced genes, and they play an important role in S. Heidelberg acid resistance. RT-PCR showed that the genes expression levels increased as acid adaptation pH decreased. The increased expression was maintained for at least 4 h during adaptation. Moreover, acid adaptation may have increased the production of cellulose and swimming in S. Heidelberg; pH 5.5 acid-adapted cells showed a red, dry, and rough morphotype on Congo red plates. The transcriptional levels of Enterotoxin gene (stn) increased three times following acid adaptation; however, the expression of Salmonella pathogenicity island 1 virulence genes significantly decreased.

• 出版日期2017-2
• 单位南京农业大学