Genetic Basis of Virulence Factors in Vibrio Cholerae: A Review

Cholera is a major epidemic disease worldwide, contributing significantly to global morbidity and mortality. The hallmark of the disease, severe watery diarrhea, results from a complex process in which multiple bacterial components enable Vibrio cholerae to reach the small intestinal epithelium, establish colonies, and produce toxins. The AraC/XylS-family transcriptional regulator, ToxT, acts as the primary activator of virulence genes in V. cholerae, the Gram-negative bacterium responsible for cholera. Unsaturated fatty acids (UFAs) present in bile can inhibit ToxT activity, thereby modulating virulence expression. Recent studies indicate that virulence in V. cholerae is not solely determined by the presence of key genes such as ctxAB and tcp. Accessory virulence-associated genes, mobile genetic elements (MGEs), regulatory networks, secretion systems, and small RNAs (sRNAs) collectively contribute to the pathogen’s ability to infect, persist, and spread. The adhesion of Vibrio cholerae to the intestinal epithelium, as well as its capacity to obtain nutrients and manipulate host immune mechanisms, is facilitated by several molecular determinants. Among these are mucin-interacting proteins such as GbpA, hemagglutinin/protease (HapA), and neuraminidase (NanH), together with various regulatory networks. The bacterium’s collective behavior and virulence expression are predominantly governed by the quorum-sensing (QS) system, which functions as a density-dependent communication network. When bacterial populations are at a low cell density (LCD), the regulatory molecules—including LuxO, HapR, and the signaling autoinducers AI-2 and CAI-1—coordinate gene expression patterns that enhance colonization capacity, stimulate biofilm development, and concurrently inhibit HapR-mediated repression. This review study highlights the genetic and molecular foundations underlying the virulence determinants that shape the pathogenic potential of V. cholerae.