Quantitative expression of cholera toxin mRNA in Vibrio cholerae isolates with different CTX cassette arrangements

Abstract

Cholera toxin (CT) is the major virulence factor produced by Vibrio cholerae. Several genomic arrangements within the CTX cassette have been elucidated in V. cholerae. Previously, it was shown that three different CTX cassette arrangements, one complete CTX cassette (arrangement A), one complete and two incomplete CTX cassettes (arrangement B), and two complete CTX cassettes (arrangement C), exist within V. cholerae isolates. In the present study, the level of CT expression by V. cholerae isolates carrying different CTX cassette arrangements was evaluated. Real-time quantitative PCR analysis showed unequal production of CT mRNA in V. cholerae isolates with different CTX arrangements. V. cholerae with the CTX arrangement C expressed more CT mRNA than isolates with the other CTX arrangements. In addition, CT mRNA was expressed more in the isolates with CTX arrangement B than in those with arrangement A. Overall, these results suggest that the arrangement and number of regulatory elements (rstA) within the CTX cassette could affect the level of expression of CT.

Facile and Rapid Detection of Vibrio cholerae by Multiplex PCR Based on ompU, ctxA, and toxR Genes

“…In the recent years, uniplex PCR method has been developed to assess the toxigenicity potency of V. cholerae (5,21), but its inability to simultaneously determine both toxigenic and regulatory factors has limited its usage. Multiplex PCR can provide a useful assay to eliminate this problem.…”

“…OmpU is the most significant outer membrane protein; it can adhere to intestinal epithelium, allowing the bacteria to colonize (7). ToxR is an transcription activating factor that positively regulates expression of several virulent genes, including ctx and toxin co-regulated pilus (TCP) genes and accessory colonization factor (ACF) genes (5,8,9). Early identification of this microorganism is essential for each health care community to alleviate the mortality rate.…”

“…Cholera toxin, encoded by ctx gene, is a potent factor which induces intense dehydration and pathogenesis (4,5). Other virulence factors involved in the pathogenecity of V. cholerae include tcp, ompU, and toxR genes (6).…”

In silico Assessment of the Genotypic Distribution of Virulence and Antibiotic Resistance Genes in Vibrio cholerae

“…Several studies documented that cholera toxin, ctx play role in diarrheal pathogenesis by inducing dehydration. 35,36 A number of virulence factors are involved in cholera pathogenesis which mediate the bacterium to colonize the epithelium layer of the small intestine and disrupt the ion balance by producing enterotoxins. 26 Blackstone et al stated that epidemic cholera caused life threating cholera gravis.…”

Evaluation of Cholera Toxin Expression in Different Populations of Vibrio cholera

“…Vibrio cholerae is the causative agent of cholera; which can cause a considerable difficulties like diarrhea, dehydrates the body, acidosis, shock and ultimately death (2). The burden of this disease is well documented in the world and so far, seven global pandemic of cholera is reported (3,4). As many scientists from all over the world believe that many pathogenic bacteria have the quorum sensing system which is one of the major virulence factors (5).…”