Purpose: This study was conducted to determine the influence of LMWC on the expression of the Shiga toxin genes, stx1 and stx2, and the intimin gene, eaeA, by STEC.
Methods: STEC strains were grown in tryptic soy broth containing 0.1% DMSO (control) and 100 µm LMWC at 37°C for 20h, and total RNA was extracted for producing the cDNA templates for PCR. Primers were designed for 16S (reference), hemX (housekeeping), stx1, stx2 and eaeA genes, and a SYBR® Green real time PCR was used to monitor gene expression.
Results: Growth of the cells and hemX gene expression were not affected by treatment with the LMWC. The expression of stx1 in E. coli O157:H7 was reduced by 74% and 72% by LMWC 1 (P ≤ 0.04) and LMWC 9 (P ≤ 0.19), respectively, while stx2 gene expression was reduced by 84% and 74% by the same compounds (P ≤ 0.03 and 0.08), respectively. The same LMWC resulted in a significant reduction of 88% and 93% (P ≤ 0.01 and 0.03) in the expression of stx2 in E. coli O111:H8, while eaeA gene expression was reduced by 34% and 25% (P≤ 0.15 and 0.23), respectively.
Significance: Results of this study show that the use of LMWC could be an alternative way to inhibit the expression of STEC virulence genes without causing cell death, which holds great potential as suitable candidates for therapeutic development.