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''Vibrio'' is a
genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
of
Gram-negative bacteria Gram-negative bacteria are bacteria that, unlike gram-positive bacteria, do not retain the Crystal violet, crystal violet stain used in the Gram staining method of bacterial differentiation. Their defining characteristic is that their cell envelo ...
, which have a characteristic curved-rod (comma) shape, several species of which can cause foodborne infection or soft-tissue infection called
Vibriosis Vibriosis or vibrio infection is an infection caused by bacteria of the genus '' Vibrio''. About a dozen species can cause vibriosis in humans, with the most common in multiple countries across the Northern Hemisphere being '' Vibrio parahaemolyt ...
. Infection is commonly associated with eating undercooked seafood. Being highly salt tolerant and unable to survive in freshwater, ''Vibrio'' spp. are commonly found in various salt water environments. ''Vibrio'' spp. are facultative anaerobes that test positive for
oxidase In biochemistry, an oxidase is an oxidoreductase (any enzyme that catalyzes a redox reaction) that uses dioxygen (O2) as the electron acceptor. In reactions involving donation of a hydrogen atom, oxygen is reduced to water (H2O) or hydrogen peroxid ...
and do not form
spores In biology, a spore is a unit of sexual (in fungi) or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plant ...
. All members of the genus are
motile Motility is the ability of an organism to move independently using metabolic energy. This biological concept encompasses movement at various levels, from whole organisms to cells and subcellular components. Motility is observed in animals, mi ...
. They are able to have polar or lateral
flagellum A flagellum (; : flagella) (Latin for 'whip' or 'scourge') is a hair-like appendage that protrudes from certain plant and animal sperm cells, from fungal spores ( zoospores), and from a wide range of microorganisms to provide motility. Many pr ...
with or without sheaths. ''Vibrio'' species typically possess two
chromosome A chromosome is a package of DNA containing part or all of the genetic material of an organism. In most chromosomes, the very long thin DNA fibers are coated with nucleosome-forming packaging proteins; in eukaryotic cells, the most import ...
s, which is unusual for bacteria. Each chromosome has a distinct and independent
origin of replication The origin of replication (also called the replication origin) is a particular sequence in a genome at which replication is initiated. Propagation of the genetic material between generations requires timely and accurate duplication of DNA by semi ...
, and are conserved together over time in the genus. Recent phylogenies have been constructed based on a suite of genes (multilocus
sequence analysis In bioinformatics, sequence analysis is the process of subjecting a DNA, RNA or peptide sequence to any of a wide range of analytical methods to understand its features, function, structure, or evolution. It can be performed on the entire genome ...
). O. F. Müller (1773, 1786) described eight species of the genus ''Vibrio'' (included in
Infusoria Infusoria is a word used to describe various freshwater microorganisms, including ciliates, copepods, Euglena, euglenoids, planktonic crustaceans, protozoa, unicellular algae and small invertebrates. Some authors (e.g., Otto Bütschli, Bütschli) ...
), three of which were spirilliforms. Some of the other species are today assigned to eukaryote taxa, e.g., to the euglenoid ''
Peranema ''Peranema'' is a genus of free-living phagotrophic euglenids (Euglenida; Euglenozoa; Excavata). There are more than 20 nominal species, varying in size between 8 and 200 micrometers. ''Peranema'' cells are gliding flagellates found in freshw ...
'' or to the
diatom A diatom (Neo-Latin ''diatoma'') is any member of a large group comprising several Genus, genera of algae, specifically microalgae, found in the oceans, waterways and soils of the world. Living diatoms make up a significant portion of Earth's B ...
'' 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. Filippo Pacini isolated micro-organisms he called " vibrions" from cholera patients in 1854, because of their motility. In
Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...
"vibrio" means "to quiver".


Biochemical characteristics of ''Vibrio'' spp.

The genus ''Vibrio'' contains a large number of species, and these vary somewhat in their biochemical characteristics. Colony, morphological, physiological, and biochemical characteristics of the genus ''Vibrio'' are shown in the Table below. Note: Group-1: ''Vibrio alginolyticus''; Group-2: ''Vibrio natriegens, Vibrio pelagius, Vibrio azureus''; + = Positive; – =Negative; V =Variable (+/–)


Pathogenic strains

Several species of ''Vibrio'' are
pathogens In biology, a pathogen (, "suffering", "passion" and , "producer of"), in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ. The term ...
. Most disease-causing strains are associated with
gastroenteritis Gastroenteritis, also known as infectious diarrhea, is an inflammation of the Human gastrointestinal tract, gastrointestinal tract including the stomach and intestine. Symptoms may include diarrhea, vomiting, and abdominal pain. Fever, lack of ...
, but can also infect open wounds and cause
sepsis Sepsis is a potentially life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. This initial stage of sepsis is followed by suppression of the immune system. Common signs and s ...
. They can be carried by numerous marine animals, such as crabs or prawns, and have been known to cause fatal infections in humans after exposure. Risk of clinical disease and death increases with certain factors, such as uncontrolled diabetes, elevated iron levels (cirrhosis,
sickle cell disease Sickle cell disease (SCD), also simply called sickle cell, is a group of inherited Hemoglobinopathy, haemoglobin-related blood disorders. The most common type is known as sickle cell anemia. Sickle cell anemia results in an abnormality in the ...
,
hemochromatosis Iron overload is the abnormal and increased accumulation of total iron in the body, leading to organ damage. The primary mechanism of organ damage is oxidative stress, as elevated intracellular iron levels increase free radical formation via the ...
), and cancer or other immunocompromised states. Pathogenic ''Vibrio'' species include '' V. cholerae'' (the causative agent of
cholera Cholera () is an infection of the small intestine by some Strain (biology), strains of the Bacteria, bacterium ''Vibrio cholerae''. Symptoms may range from none, to mild, to severe. The classic symptom is large amounts of watery diarrhea last ...
), '' V. parahaemolyticus'', and '' V. vulnificus.'' ''V. cholerae'' is generally transmitted by contaminated water. 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. The pathogenic features can be linked to
quorum sensing In biology, quorum sensing or quorum signaling (QS) is the process of cell-to-cell communication that allows bacteria to detect and respond to cell population density by gene regulation, typically as a means of acclimating to environmental disadv ...
, where bacteria are able to express their virulence factor via their signaling molecules. ''V. vulnificus'' outbreaks commonly occur in warm climates and small, generally lethal, outbreaks occur regularly. An outbreak occurred in New Orleans after
Hurricane Katrina Hurricane Katrina was a powerful, devastating and historic tropical cyclone that caused 1,392 fatalities and damages estimated at $125 billion in late August 2005, particularly in the city of New Orleans and its surrounding area. ...
, and several lethal cases occur most years in Florida. 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 Shellfish, in colloquial and fisheries usage, are exoskeleton-bearing Aquatic animal, aquatic invertebrates used as Human food, food, including various species of Mollusca, molluscs, crustaceans, and echinoderms. Although most kinds of shellfish ...
. ''V. parahaemolyticus'' is also associated with the Kanagawa phenomenon, in which strains isolated from human
hosts A host is a person responsible for guests at an event or for providing hospitality during it. Host may also refer to: Places * Host, Pennsylvania, a village in Berks County * Host Island, in the Wilhelm Archipelago, Antarctica People * ...
(clinical isolates) are
hemolytic Hemolysis or haemolysis (), also known by several other names, is the rupturing (lysis) of red blood cells (erythrocytes) and the release of their contents (cytoplasm) into surrounding fluid (e.g. blood plasma). Hemolysis may occur in vivo ...
on blood agar plates, while those isolated from nonhuman sources are not hemolytic. Many ''Vibrio'' species are also
zoonotic A zoonosis (; plural zoonoses) or zoonotic disease is an infectious disease of humans caused by a pathogen (an infectious agent, such as a virus, bacterium, parasite, fungi, or prion) that can jump from a non-human vertebrate to a human. When h ...
. They cause disease in fish and shellfish, and are common causes of mortality among domestic marine life.


Diagnosis


Cholera

A common sign of ''Vibrio'' infection is
cholera Cholera () is an infection of the small intestine by some Strain (biology), strains of the Bacteria, bacterium ''Vibrio cholerae''. Symptoms may range from none, to mild, to severe. The classic symptom is large amounts of watery diarrhea last ...
. Cholera primarily presents with rapid water loss by watery diarrhea. Other symptoms include vomiting and muscle cramps. Water loss can lead to dehydration which can be mild to moderate to severe. Moderate to severe dehydration requires immediate treatment. '' V. cholerae'' is the most common pathogen that causes cholera. The gold standard for detecting cholera is through cultures of stool samples or rectal swabs. Identification is then done through microscopy or by agglutination of antibodies. Cultures are done in thiosulfate citrate bile-salts sucrose agar. ''V cholerae'' will form yellow colonies.


Vibriosis

Vibriosis is a sign of a more severe ''Vibrio'' infection. Common causes of vibriosis include consumption of raw or undercooked seafood, primarily oysters, or wound exposure to sea water. The majority of ''V. parahaemolyticus'' infections can be self-limiting and symptoms include diarrhea, nausea, headaches, fever and chills. ''V. vulnificus'' can lead to a more serious disease, particularly in wound infection which can turn into
necrotizing fasciitis Necrotizing fasciitis (NF), also known as flesh-eating disease, is an infection that kills the body's soft tissue. It is a serious disease that begins and spreads quickly. Symptoms include red or purple or black skin, swelling, severe pain, fever ...
. ''V. parahaemolyticu''s is the most common pathogen in vibriosis, however ''V. vulnificus'' is more common in people who have certain risk factors like older age, liver disease or diabetes mellitus. Like all vibrio diagnosis, vibriosis can also be determined in stool cultures. ''V. parahaemolyticus'' and ''V. vulnificus'' will form green colonies.


Treatment

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


''Vibrio'' gastroenteritis

Because ''Vibrio'' gastroenteritis is self-limited in most patients, no specific medical therapy is required. Patients who cannot tolerate oral fluid replacement may require intravenous fluid therapy. Although most ''Vibrio'' species are sensitive to antibiotics, such as
doxycycline Doxycycline is a Broad-spectrum antibiotic, broad-spectrum antibiotic of the Tetracycline antibiotics, tetracycline class used in the treatment of infections caused by bacteria and certain parasites. It is used to treat pneumonia, bacterial p ...
or
ciprofloxacin Ciprofloxacin is a fluoroquinolone antibiotic used to treat a number of bacterial infections. This includes bone and joint infections, intra-abdominal infections, certain types of infectious diarrhea, respiratory tract infections, skin ...
, antibiotic therapy does not shorten the course of the illness or the duration of pathogen excretion. However, if the patient is ill and has a high fever or an underlying medical condition, oral antibiotic therapy with doxycycline or ciprofloxacin can be initiated.


Non-cholera'' Vibrio'' infections

Patients with non-cholera ''Vibrio'' wound infection or sepsis are much more ill and frequently have other medical conditions. Medical therapy consists of: * Prompt initiation of effective antibiotic therapy (doxycycline or a quinolone) * Intensive medical therapy with aggressive fluid replacement and vasopressors for hypotension and septic shock to correct acid-base and electrolytes abnormalities that may be associated with severe sepsis * Early
fasciotomy Fasciotomy or fasciectomy is a surgical procedure where the fascia is cut to relieve tension or pressure in order to treat the resulting loss of circulatory system, circulation to an area of biological tissue, tissue or muscle. Fasciotomy is a li ...
within 24 hours after development of clinical symptoms can be life-saving in patients with
necrotizing fasciitis Necrotizing fasciitis (NF), also known as flesh-eating disease, is an infection that kills the body's soft tissue. It is a serious disease that begins and spreads quickly. Symptoms include red or purple or black skin, swelling, severe pain, fever ...
. * Early
debridement Debridement is the medical removal of dead, damaged, or infected tissue to improve the healing potential of the remaining healthy tissue. Removal may be surgical, mechanical, chemical, autolytic (self-digestion), or by maggot therapy. In ...
of the infected wound has an important role in successful therapy and is especially indicated to avoid amputation of fingers, toes, or limbs. * Expeditious and serial surgical evaluation and intervention are required because patients may deteriorate rapidly, especially those with necrotizing fasciitis or
compartment syndrome Compartment syndrome is a serious medical condition in which increased pressure within a Fascial compartment, body compartment compromises blood flow and tissue function, potentially leading to permanent damage if not promptly treated. There are ...
. * Reconstructive surgery, such as skin grafts, are used in the recovery phase.


Prevention


Cholera

The most effective method to prevent cholera is the improvement of water and food safety. This includes the sanitation of water, proper preparation of food and community awareness of outbreaks. Prevention has been most effective in countries where cholera is endemic. Another method is
cholera vaccine A cholera vaccine is a vaccine that is effective at reducing the risk of contracting cholera. The recommended cholera vaccines are administered orally to elicit local immune responses in the gut, where the intestinal cells produce antibodies ...
s. Examples of cholera vaccines include Dukoral and Vaxchora.


Vibriosis

Prevention of vibriosis is mostly effective in food processing. Food items, mostly seafood, that commonly contain ''vibrio'' organisms are regularly controlled. The water that seafood is fished or farmed from is analyzed to determine microorganism content. Food processing methods like pasteurization and high pressure are used to eliminate microorganisms and pathogens.


Other strains

''V. harveyi'' is a pathogen of several aquatic animals, and is notable as a cause of luminous vibriosis in shrimp (prawns). '' Aliivibrio fischeri'' (or ''V. fischeri'') is known for its mutualistic symbiosis with the Hawaiian
bobtail squid Bobtail squid (order Sepiolida) are a group of cephalopods closely related to cuttlefish. Bobtail squid tend to have a rounder mantle (mollusc), mantle than cuttlefish and have no cuttlebone. They have eight suckered arms and two tentacles and ar ...
, which is dependent on microbial luminescence.


Flagella

The "typical", early-discovered ''Vibrio'' species, such as ''V. cholerae'', have a single polar
flagellum A flagellum (; : flagella) (Latin for 'whip' or 'scourge') is a hair-like appendage that protrudes from certain plant and animal sperm cells, from fungal spores ( zoospores), and from a wide range of microorganisms to provide motility. Many pr ...
(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).


Structure

Typical bacterial flagellum structure contains three components: the basal body, the hook and the filament. Like typical bacteria, ''Vibrio'' spp, have these three components, but with increased complexity in the basal body. In addition, ''Vibrio'' spp. use five or six distinct flagellum subunits to construct the flagellar filament, rather than the single flagellin found in many other bacteria. In ''Vibrio'' spp, most have a single flagellum located on one pole of the bacterium, although some species have additional flagella in peritrichous or lophotrichous arrangements. Another difference is that the gradient used to power the flagellar motor is sodium driven rather than proton driven; this creates greater torque, and ''Vibrio'' flagella have been shown to rotate over five times faster than the -driven flagella of ''E. coli''. The flagellum is also surrounded by a sheath extending from the membrane. The purpose of this sheath has yet to be determined.


Effect on Virulence

Motility is very important for ''Vibrio'' spp for infection. Research has shown that a variety of ''Vibrios'' mutants that are defective in flagella synthesis or non-motile are defective in infection. Loss of motility in ''Vibrio'' has shown impaired colonization and adherence to host's intestines.


Natural transformation

Natural transformation In category theory, a branch of mathematics, a natural transformation provides a way of transforming one functor into another while respecting the internal structure (i.e., the composition of morphisms) of the categories involved. Hence, a natur ...
is a common bacterial adaptation for DNA transfer that employs numerous bacterial gene products. 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 ratchet and reels DNA into the periplasm. Natural transformation has also been described for ''V. fischeri'', ''V. vulnificus'' and ''V. parahaemolyticus''.


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 In molecular biology, reading frames are defined as spans of DNA sequence between the start and stop codons. Usually, this is considered within a studied region of a prokaryotic DNA sequence, where only one of the six possible reading frames ...
(ORF) and ORF-derived. One of the candidates from this study, IGR 7, 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, MiX sRNA, Vibrio cholerae ToxT activated RNAs, foR RNA, and VqmR sRNA.


See also

*
Cholera toxin Cholera toxin (also known as choleragen, CTX, CTx and CT) is a potent enterotoxin produced by the bacterium Vibrio cholerae which causes severe watery diarrhea and dehydration that define cholera infections. The toxin is a member of the heat-l ...
* Climate change and infectious diseases


References


External links


Vibrio
genomes and related information a
PATRIC
a Bioinformatics Resource Center funded b
NIAID


{{Taxonbar, from=Q753490 Bacteria genera Food microbiology Vibrionales