Yersinia pestis is a gram-negative, non-motile, coccobacillus bacterium without spores that is related to both Yersinia enterocolitica and Yersinia pseudotuberculosis, the pathogen from which Y. pestis evolved and responsible for the Far East scarlet-like fever. It is a facultative anaerobic organism that can infect humans via the Oriental rat flea. It causes the disease plague, which caused the Plague of Justinian and the Black Death, the deadliest pandemic in recorded history. Plague takes three main forms: pneumonic, septicemic, and bubonic. Yersinia pestis is a parasite of its host, the rat flea, which is also a parasite of rats, hence Y. pestis is a hyperparasite.
Yersinia is a genus of bacteria in the family Yersiniaceae. Yersinia species are Gram-negative, coccobacilli bacteria, a few micrometers long and fractions of a micrometer in diameter, and are facultative anaerobes. Some members of Yersinia are pathogenic in humans; in particular, Y. pestis is the causative agent of the plague. Rodents are the natural reservoirs of Yersinia; less frequently, other mammals serve as the host. Infection may occur either through blood or in an alimentary fashion, occasionally via consumption of food products contaminated with infected urine or feces.
Yersinia enterocolitica is a Gram-negative, rod-shaped bacterium, belonging to the family Yersiniaceae. It is motile at temperatures of 22–29°C (72–84°F), but becomes nonmotile at normal human body temperature. Y. enterocolitica infection causes the disease yersiniosis, which is an animal-borne disease occurring in humans, as well as in a wide array of animals such as cattle, deer, pigs, and birds. Many of these animals recover from the disease and become carriers; these are potential sources of contagion despite showing no signs of disease. The bacterium infects the host by sticking to its cells using trimeric autotransporter adhesins.
Yersiniosis is an infectious disease of the gastrointestinal tract caused by bacteria of the genus Yersinia other than Y. pestis. Most cases of yersiniosis in humans are caused by Y. enterocolitica, with a small minority being caused by Y. pseudotuberculosis. Rarely, other species of the genus can cause yersiniosis.
Yersinia pseudotuberculosis is a Gram-negative bacterium that causes Far East scarlet-like fever in humans, who occasionally get infected zoonotically, most often through the food-borne route. Animals are also infected by Y. pseudotuberculosis. The bacterium is urease positive.
Yersinia intermedia is a Gram-negative species of bacteria which uses rhamnose, melibiose, and raffinose. Its type strain is strain 3953. It has been found in fish, and contains several biotypes. It is not considered of clinical relevance, being isolated from humans in a routine manner.
Yersinia aldovae is a species of bacteria that was originally described as Group X2 Yersinia enterocolitica. Its type strain is CNY 6005. Y. aldovae has been isolated from aquatic environments and soil, but it has not been associated with animal or human illnesses.
Yersinia entomophaga is a species of bacteria that was originally isolated from the diseased larvae of the New Zealand grass grub, Costelytra zealandica. The type strain is MH96. It is currently being studied for biological pest control of insect pests like the porina moth, Wiseana cervinata.
Yersinia hibernica is a species of Yersinia that was originally isolated in a pig-production environment. The type strain is CFS1934. This species has previously been misidentified as Yersinia enterocolitica and Yersinia kristensenii but it may be distinguished biochemically by lack of sucrose utilization. In addition to pig related environments, Y. hibernica has also been isolated from the feces of Rattus norvegicus and Hydrochoerus hydrochaeris.
Yersinia aleksiciae is a Gram-negative bacteria that is commonly isolated from the feces of warm-blooded animals such as humans, reindeers, and pigs. The type strain is Y159.
Yersinia massiliensis is a Gram-negative bacteria that is commonly isolated from the environment and food. The type strain is CCUG 53443.
Yersinia rohdei is a Gram-negative species of Yersinia that was originally isolated from the feces of humans and dogs in addition to water surfaces. The type strain is ATCC 43380. Y. rohdei strains have also been isolated from reindeer and kelp gull from the sub-Antarctica South Georgia island.
Yersinia similis is a Gram-negative bacteria species of Yersinia that resembles Yersinia pseudotuberculosis phenotypically but differs on the basis of 16S ribosomal RNA sequences. The type strain Y228 was originally isolated from a rabbit in Germany.
Yersinia thracica is a Gram-negative species of enteric bacteria in the Yersinia genus that is closely related to Yersinia kristensenii. Reportedly, it has only been isolated in animals. The type strain, IP34646T, was isolated from diseased rainbow trout while other isolates are from birds, pig feces, and wild boars.
Yersinia vastinensis is a Gram-negative species of bacteria that has been isolated from human stools. All reported strains were isolated in France.
Yersinia rochesterensis is a Gram-negative, motile, rod-shaped bacterium that forms circular colonies and was isolated from human feces. This potentially pathogenic species has been isolated in human stools in France and in the United States where it was characterized at the Mayo Clinic. A Y. rochesterensis strain, isolated from hare and initially identified as Yersinia kristensenii, was serotyped as O:12,25.
Yersinia proxima is a Gram-negative bacterium in the family Yersiniaceae that is phylogenetically close to Yersinia enterocolitica. Members of this species has been found in human feces.
Yersinia alsatica is a Gram-negative bacterium in the family Yersiniaceae that has been isolated from human stool.
Yersinia artesiana are short Gram-negative rod bacteria in the Yersiniaceae family that have been isolated from human stool.
