Pathogens

Vibrio parahaemolyticus – Infection, Transmission & Diseases

Vibrio parahaemolyticus

Vibrio parahaemolyticus is a bacterial species containing many individual strains. The bacteria prefer to live in seawater and can spread to the human intestine , especially when undercooked fish and seafood are eaten. Not all strains of the bacterium are considered human pathogens.

What is Vibrio parahaemolyticus?

In the bacterial department of the Proteobacteria, the Gammaproteobacteria form their own class. It includes orders such as the Vibrionales, which in turn includes the Vibrionaceae family of bacteria. This family contains the vibrio genus, which includes several species of gram-negative, facultatively anaerobic, and curved rod -shaped bacteria with unipolar flagella. The bacteria from this genus are capable of active locomotion thanks to their flagellation.

One species of Vibrios is the Vibrio parahaemolyticus bacterial species with its individual strains. The pathogenicity of the bacteria was recorded by Fujino Tsunesaburō after a bacterial disease wave in Japan in 1951. Infections with Vibrio parahaemolyticus have also been common in North and South America since the late 1990s . Cases of gastrointestinal infections have also been documented in Europe.

An enormous number of different strains are associated with Vibrio parahaemolyticus, which are subdivided into serotypes depending on intracellular antigens . 76 serotypes have been identified so far. Twelve of them are pathogenic pathogens. The pathogenicity of other strains is still unclear and is currently still an object of research.

Occurrence, Distribution & Properties

Facultatively anaerobic bacteria grow optimally in the presence of oxygen , but can also live in the absence of O2 by switching their metabolism. As a facultative anaerobic bacterial species, the species Vibrio parahaemolyticus is not necessarily dependent on an oxygen-rich environment for growth, although its growth is favored by oxygen. 

The strains of the species possess the enzymes catalase and oxidase. The ideal temperatures for growth are between 10 and -15 degrees Celsius. The bacteria can also live well at higher temperatures, for example at degrees Celsius between 20 and 30. This makes the bacterium a mesophilic bacterium.

Like other members of the superior genus, the species Vibrio parahaemolyticus operates chemoorganotrophic as well as heterotrophic metabolism. As a result, the bacteria use organic compounds as a source of energy and also build cell-specific substances from them. The bacteria are capable of utilizing various substrates in the form of fermentation. They metabolize carbohydrates such as glucose , arabinose or mannose, for example by fermentation to acids or similar products. Thanks to the enzymes ornithine decarboxylase and lysine decarboxylase, they are able to separate carbon dioxide from amino acids such as ornithine and lysine .

The natural habitat of the Vibrio parahaemolyticus species is the water, where it is increasingly found, especially in the summer months. The bacterium prefers to live in seawater, especially in brackish and coastal waters. From temperatures of around 14 degrees Celsius, the bacteria are released from the sediment and attach themselves to plankton components, causing transmission to fish and crustaceans. Transmission to humans can occur through the consumption of contaminated sea creatures such as oysters , which are often eaten raw.

Infection can also occur through insufficiently treated drinking water. In individual cases, bacterial penetration was also observed via smaller wounds with which the person concerned had been swimming in contaminated water.

Not all strains of the bacterium are human pathogens. Some, after entering the human organism, behave as commensals, causing neither harm nor benefit.

Diseases & Ailments

12 pathogenic serotypes of Vibrio parahaemolyticus have been described so far. These serotypes are primarily associated with the bacterial infection of gastroenteritis . O3:K6 is the most commonly identified serotype. This is the strain Vibrio parahaemolyticus RIMD 2210633. The serotypes O1:K25, O1:K41, O1:K56, O3:K75, O4:K8 and O5:KUT are also considered pathogenic.Infections with Vibrio parahaemolyticus are particularly common in Asia, such as Japan, Taiwan and Southeast Asia. In 1998 there was an epidemic in Texas and twelve other US states. A little later, epidemic infections were also documented in Chile. Within Europe, France suffered the most serious cases of infection.

The preferred route of infection of the bacterial species Vibrio parahaemolyticus is the faecal-oral route. Raw or undercooked fish such as mackerel, tuna, sardines and eel or seafood such as crabs, squid, shrimp, lobster and mussels are considered the most common sources of infection. More rarely, people contract the infection through a wound while bathing in warm sea water.

Infection with pathogenic strains of the bacterial species provokes acute gastroenteritis. Superficial wound infections and sepsis ( blood poisoning ) are also conceivable but rather rare symptoms. After an incubation period of up to one day, those affected experience watery diarrhea , abdominal pain , nausea , fever and vomiting .

The symptoms usually last three days, and in immunocompromised patients up to ten days. Drug therapy is only required if the bacteria enter the blood and there is a risk of sepsis. In severe cases of infection, an antibiotic such as doxycycline or ciprofloxacin is given in addition to electrolyte and fluid replacement through infusions . Since immunocompromised patients generally have a higher risk of complications, they are generally given medication in the event of an infection.

Lisa Newlon
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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.