Vibrio

Vibrio
Flagellar stain of V. cholerae
Scientific classification
Domain:	Bacteria
Phylum:	Proteobacteria
Class:	Gammaproteobacteria
Order:	Vibrionales
Family:	Vibrionaceae
Genus:	Vibrio Pacini 1854
Type species
Vibrio cholerae
Species
V. adaptatus V. aerogenes V. aestivus V. aestuarianus V. agarivorans V. albensis V. alfacsensis V. alginolyticus V. anguillarum V. areninigrae V. artabrorum V. atlanticus V. atypicus V. azureus V. brasiliensis V. bubulus V. calviensis V. campbellii V. casei V. chagasii V. cholerae V. cincinnatiensis V. coralliilyticus V. crassostreae V. cyclitrophicus V. diabolicus V. diazotrophicus V. ezurae V. fluvialis V. fortis V. furnissii V. gallicus V. gazogenes V. gigantis V. halioticoli V. harveyi V. hepatarius V. hippocampi V. hispanicus V. ichthyoenteri V. indicus V. kanaloae V. lentus V. litoralis V. logei V. mediterranei V. metschnikovii V. mimicus V. mytili V. natriegens V. navarrensis V. neonatus V. neptunius V. nereis V. nigripulchritudo V. ordalii V. orientalis V. pacinii V. parahaemolyticus V. pectenicida V. pelagius V. penaeicida V. pomeroyi V. ponticus V. proteolyticus V. rotiferianus V. ruber V. rumoiensis V. salmonicida V. scophthalmi V. splendidus V. superstes V. tapetis V. tasmaniensis V. tubiashii V. vulnificus V. wodanis V. xuii Moved: V. fischeri to Aliivibrio fischeri V. hollisae to Grimontia hollisae

Vibrio is a genus of Gram-negative bacteria, possessing a curved-rod (comma) shape,^[1][2][3][4] several species of which can cause foodborne infection, usually associated with eating undercooked seafood. Typically found in salt water, Vibrio species are facultative anaerobes that test positive for oxidase and do not form spores.^[4][5] All members of the genus are motile. They are able to have polar or lateral flagellum with or without sheaths.^[4][6] Vibrio species typically possess two chromosomes, which is unusual for bacteria.^[7][8] Each chromosome has a distinct and independent origin of replication,^[9] and are conserved together over time in the genus.^[10] Recent phylogenies have been constructed based on a suite of genes (multilocus sequence analysis).^[1]

O. F. Müller (1773, 1786) described eight species of the genus Vibrio (included in Infusoria), three of which were spirilliforms.^[11] Some of the other species are today assigned to eukaryote taxa, e.g., to the euglenoid Peranema or to the diatom Bacillaria. However, Vibrio Müller, 1773 became regarded as the name of a zoological genus, and the name of the bacterial genus became Vibrio Pacini, 1854.^[12][13] Filippo Pacini isolated micro-organisms he called "vibrions" from cholera patients in 1854, because of their motility.^[14] In Latin "vibrio" means "to quiver".^[15]

Vibrio spp. are commonly found in marine environments. Marine Vibrio species are highly salt tolerant and can grow in wide range of salinity.^[4] S.I. Paul et al. (2021)^[4] isolated, characterized, and identified multiple strains of Vibrio species (Vibrio alginolyticus, Vibrio natriegens, Vibrio pelagius, Vibrio azureus) from marine sponges of the Saint Martin's Island Area of the Bay of Bengal, Bangladesh. Where, Vibrio species were found most dominant bacteria in marine environment.^[4]

Biochemical characteristics of Vibrio spp.

The genus Vibrio contains a large number of species. So, variation in the biochemical characteristics are most common in case of the genus Vibrio. Colony, morphological, physiological, and biochemical characteristics of the genus Vibrio  are shown in the Table below.^[4]

Note: Group-1: Vibrio alginolyticus; Group-2: Vibrio natriegens, Vibrio pelagius, Vibrio azureus; + = Positive; – =Negative; V =Variable (+/–)

Pathogenic strains

TCBS agar plate of Vibrio Cholerae (left) and Vibrio parahaemolyticus (right)

Several species of Vibrio are pathogens.^[16] Most disease-causing strains are associated with gastroenteritis, but can also infect open wounds and cause sepsis.^[17] They can be carried by numerous marine animals, such as crabs or prawns, and have been known to cause fatal infections in humans during exposure.^[18] Risk of clinical disease and death increases with certain factors, such as uncontrolled diabetes, elevated iron levels (cirrhosis, sickle cell disease, hemochromatosis), and cancer or other immunocompromised states. Pathogenic Vibrio species include V. cholerae (the causative agent of cholera), V. parahaemolyticus, and V. vulnificus. V. cholerae is generally transmitted by contaminated water.^[3] Pathogenic Vibrio species can cause foodborne illness (infection), usually associated with eating undercooked seafood. When ingested Vibrio bacteria can primarily result in watery diarrhea along with other secondary symptoms^[19].The pathogenic features can be linked to quorum sensing, where bacteria are able to express their virulence factor via their signalling molecules.^[20]

V. vulnificus outbreaks commonly occur in warm climates and small, generally lethal, outbreaks occur regularly. An outbreak occurred in New Orleans after Hurricane Katrina,^[21] and several lethal cases occur most years in Florida.^[22] As of 2013 in the United States, Vibrio infections as a whole were up 43% when compared with the rates observed in 2006–2008. V. vulnificus, the most severe strain, has not increased. Foodborne Vibrio infections are most often associated with eating raw shellfish.^[23]

V. parahaemolyticus is also associated with the Kanagawa phenomenon, in which strains isolated from human hosts (clinical isolates) are hemolytic on blood agar plates, while those isolated from nonhuman sources are not hemolytic.^[24]

Many Vibrio species are also zoonotic. They cause disease in fish and shellfish, and are common causes of mortality among domestic marine life.

Treatment

Medical care depends on the clinical presentation and the presence of underlying medical conditions.

Other strains

V. harveyi is a pathogen of several aquatic animals, and is notable as a cause of luminous vibriosis in shrimp (prawns).^[26] V. fischeri (or Aliivibrio fishceri) is known for its mutualistic symbiosis with the Hawaiian bobtail squid, which is dependent on microbial luminescence.^[27]

Flagella

The "typical", early-discovered Vibrio species, such as V. cholerae, have a single polar flagellum (monotrichous) with sheath. Some species, such as V. parahaemolyticus and V. alginolyticus, have both a single polar flagellum with sheath and thin flagella projecting in all directions (peritrichous), and the other species, such as V. fischeri, have tufts of polar flagella with sheath (lophotrichous).^[28]

Natural transformation

Natural transformation is a common bacterial adaptation for DNA transfer that employs numerous bacterial gene products.^[29][30] For a recipient bacterium to bind, take up, and recombine exogenous DNA into its chromosome, it must become competent, that is, enter a special physiologic state. The DNA-uptake process of naturally competent V. cholerae involves an extended competence-induced pilus and a DNA-binding protein that acts as a rachet and reels DNA into the periplasm.^[31] Natural transformation has also been described for V. fisheri,^[32] V. vulnificus^[33] and V. parahaemolyticus.^[34]

Small RNA

V. cholerae has been used in discoveries of many bacterial small RNAs. Using sRNA-Seq and Northern blot candidate sRNAs were identified and characterised as IGR-sRNA (intragenic region), AS-sRNAs (transcribed from the antisense strand of the [[open reading frame (ORF) and ORF-derived.^[35] One of the candidates from this study, IGR7, was shown to be involved in carbon metabolism and later renamed MtlS RNA. Other sRNAs identified in V. cholerae through genetic screens and computational methods include Qrr RNA, Vibrio regulatory RNA of OmpA, MicX sRNA, Vibrio cholerae ToxT activated RNAs, tfoR RNA, and VqmR sRNA.

See also

• Cholera toxin

References

External links

• Vibrio genomes and related information at PATRIC, a Bioinformatics Resource Center funded by NIAID
• Bacteriological Analytical Manual Online