Vibrio is a bacterial genus which is found in temperate to warm aquatic environments all over the world. The most famous species in this genus is probably V. cholerae, the bacterium which is responsible for causing cholera. Cholera is a disease which causes substantial public health problems in warm areas of the world, and the study of cholera played a critical role in the development of the germ theory of disease, which states that microorganisms are responsible for many diseases.
Bacteria in this genus are Gram negative, and most require saline environments to survive, although this is not true of all species. They are facultative anaerobes, which means that they do not require oxygen to survive, and they are highly motile, with tiny flagella which allow them to remove rapidly through the environment. Depending on the species, the bacteria can be S-shaped or comma-shaped.
There are several notable species within the Vibrio genus. A few species demonstrate the trait of bioluminescence, and many others can cause a variety of gastrointestinal symptoms similar to those experienced by cholera patients. Many species are also zoonotic, which allows them to hop from species to species to ensure that they are widely distributed. Shellfish, for example, can house Vibrio bacteria which may make people sick.
Vibrio vulnificus, another notable species, is endemic to several warm climates. In addition to causing intestinal infections, this bacterium can also infect the skin, and it will take advantage of open wounds to spread into the bloodstream, causing septicemia. People with compromised immune systems are at especially high risk of contracting a dangerous infection from this particular Vibrio species.
Many of these species are foodborne, leading some doctors to classify Vibrio infection as a foodborne illness. However, because they live in aquatic environments, they can also spread through contaminated water supplies. This can become an especially large issue when sewage spills occur, as untreated sewage can contain bacteria which will enter the water supply and make people sick.
These bacteria often need warm climates to survive, but many can develop dormancy, which allows them to overwinter and appear again in the spring and summer in areas with cold winter. The ability to overwinter is very useful from the point of view of the bacteria, because it ensures that the organisms will survive in a variety of climates. For microbiologists and public health officials, this trait is extremely irritating, as it makes it extremely difficult to eradicate Vibrio bacteria.