| Vibrionaceae | |
|---|---|
 | |
| Vibrio cholerae | |
Scientific classification | |
| Domain: | Bacteria |
| Kingdom: | Pseudomonadati |
| Phylum: | Pseudomonadota |
| Class: | Gammaproteobacteria |
| Order: | Vibrionales Garrity and Holt 2001 |
| Family: | Vibrionaceae Véron 1965 (Approved Lists 1980) |
| Genera | |
| |
TheVibrionaceae are a family ofPseudomonadota given their own order,Vibrionales. Inhabitants of fresh or salt water, several species arepathogenic, including the type speciesVibrio cholerae, which is the agent responsible forcholera. Mostbioluminescent bacteria belong to this family, and are typically found assymbionts of deep-sea animals.[1]
Vibrionaceae areGram-negative organisms andfacultative anaerobes, capable offermentation. They containoxidase and have one or moreflagella, which are generally polar. Originally, these characteristics defined the family, which was divided into four genera. Two of these,Vibrio andPhotobacterium, correspond to the modern group, although several new genera have been defined. Genetic studies have shown the other two original members—Aeromonas andPlesiomonas—belong to separate families. The family Vibrionaceae currently comprises eight validly published genera:Aliivibrio,[2]Catenococcus,Enterovibrio,Grimontia,Listonella,Photobacterium,Salinivibrio, andVibrio; although the status ofListonella has been questioned.
Members of this family also synthesizetetrodotoxin (TTX), an ancient marinealkaloid and powerfulneurotoxin (Na+ pump inhibitor, 1 mg can kill an adult) that serves to protect members of anorder of fishes, theTetraodontiformes (tetras-four andodontos-tooth), which include the puffer fish (seefugu, raw puffer fish served in Japan). As mentioned above, Vibrionaceae bacteria are in symbiosis with many marine organisms.[3] In the case of the puffer fish, and other marine organisms harboring TTX-producing Vibrionaceae, the symbiosis is an ancient and powerful one, providing protection against predation for the marine organisms that harbor these bacteria, while providing the bacteria a protected environment with plenty of nutrients for growth. TTX and saxitoxin provide good examples of convergent biochemical evolution: both toxins are extremely toxic at low levels, both are Na+ pump inhibitors and both have nearly identical binding constants on the Na+ pump in neurons.[4]
A characteristic of the family is the broad host range susceptible to infection by vibrios. Pathogens of man, other thanV. cholerae, includeV. parahaemolyticus, a cause ofgastroenteritis andV. vulnificus that can lead to acute and fatalsepticaemia. Other species of Vibrionaceae are associated with disease in a wide variety offinfish, one of the most notable and commonly occurring pathogens beingVibrio anguillarum, the cause of septicaemia in farmed salmonids such as Atlantic salmon and rainbow trout.[5] Species such asV. tubiashii cause disease in larval stages of Pacific oyster (Crassostrea gigas) whileV. harveyi causesluminous vibriosis inpenaeid shrimps (prawns). The extent of the host range is seen with species such asV. mediterranei andV. coralliilyticus, which can infectzooxanthellae, the plant symbionts of coral. These species ofVibrio are thought to be a cause ofcoral bleaching.[6][7]
