toxigene

Toxigene refers to a gene or gene cluster that encodes a toxin or controls toxin production in microorganisms. These genetic elements can determine whether a microbe is capable of producing a toxin and, in some cases, how much toxin is produced.

Most toxigenic genes are located on mobile genetic elements such as plasmids, bacteriophages, or genomic islands, which facilitates horizontal transfer between strains. They may encode the toxin protein itself or regulatory factors that activate toxin expression in response to environmental cues such as host signals, nutrient status, or quorum sensing.

Well-known examples include the ctxAB toxin genes of Vibrio cholerae, which reside on the CTXφ phage; the botulinum toxin gene clusters in Clostridium botulinum; and the diphtheria toxin gene (tox) carried by a lysogenic phage in Corynebacterium diphtheriae. Toxigenic genes are often key virulence determinants and can define a strain's pathogenic potential.

Detection and study of toxigene sequences using molecular methods such as PCR and sequencing are important in clinical diagnostics, food safety, and epidemiology. The study of toxigene mobility also informs biosafety and public health, given the potential for horizontal transfer to alter virulence profiles.