Evaluation of the Expression of Virulence Factors of <i>V. cholerae</i> After Interaction With the Human Colon Adenocarcinoma (Caco‐2) Cell Line

Cholera remains a global challenge, and understanding how <i>V</i>. <i>cholerae</i> adapts to environmental condition is essential for innovating new management strategies. This research aims to examine the expression of <i>ctxAB</i>, <i>tcpA</i>, and <i>hlyA</i> genes in <i>V</i>. <i>cholerae</i> (El Tor and classical biotypes) after interaction with Caco-2 cells compared to brain heart infusion (BHI) broth. After assaying of viability of Caco-2 cells against <i>V</i>. <i>cholerae</i> at multiplicity of infection (MOI) of 10, 20, 50, and 80, the number of bacteria attached to Caco-2 cells was determined using the adhesion assay. To conduct a valid comparison, an equivalent number of bacteria that attached to Caco-2 cells was inoculated into BHI broth. The expression of <i>ctxAB</i>, <i>tcpA</i>, and <i>hlyA</i> genes in <i>V</i>. <i>cholerae</i> (El Tor and classical biotypes) was assayed using the real-time PCR method. After interaction of Caco-2 cells with <i>V</i>. <i>cholerae</i>, the expression of the genes <i>ctxAB</i>, <i>tcpA</i>, and <i>hlyA</i> in the El Tor biotype increased by 2-, 1.02-, and 7-fold, respectively, while in the classical biotype, it increased by 6-, 2-, and 13-fold, respectively. The expression of the genes <i>ctxAB</i> and <i>hlyA</i> was significantly increased in Caco-2 cells in both biotypes. There was a significant increase in the expression of the gene <i>tcpA</i> in the classical biotype, while no significant increase was detected in the expression of this gene in the El Tor biotype. Caco-2 cells induced the highest increase in <i>hlyA</i> gene expression in the classical biotype, while there was no significant effect on <i>tcpA</i> gene expression in the El Tor biotype of <i>V</i>. <i>cholerae</i>. In conclusion, <i>V</i>. <i>cholerae</i> showed greater pathogenicity in the Caco-2 cells. Knowing the behavior of <i>V</i>. <i>cholerae</i> in different conditions can lead to create innovative strategies for combating and managing cholera.