Gram-negative in the context of "Enteropathogenic Escherichia coli"

Septicemic plague is one of the three forms of plague, and is caused by Yersinia pestis, a gram-negative species of bacterium. Septicemic plague is a systemic disease involving infection of the blood and is most commonly spread by bites from infected fleas. Septicemic plague can cause disseminated intravascular coagulation and is always fatal when untreated. The other varieties of the plague are bubonic plague and pneumonic plague.

Pasteurella is a genus of Gram-negative, facultatively anaerobic bacteria. Pasteurella species are nonmotile and pleomorphic, and often exhibit bipolar staining ("safety pin" appearance). Most species are catalase- and oxidase-positive.The genus is named after the French chemist and microbiologist, Louis Pasteur, who first identified the bacterium now known as Pasteurella multocida as the agent of chicken cholera.

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 it 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.

Y. enterocolitica is widespread in nature, occurring in reservoirs ranging from the intestinal tracts of numerous mammals, avian species, cold-blooded species, and even from terrestrial and aquatic niches. Most environmental isolates are avirulent; however, isolates recovered from porcine sources contain human pathogenic serogroups. In addition, dogs, sheep, wild rodents, and environmental water may also be a reservoir of pathogenic Y. enterocolitica strains. Human pathogenicstrains are usually confined to the intestinal tract and lead to enteritis/diarrhea.

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.

Coliform bacteria are defined as either motile or non-motile Gram-negative non-spore forming bacilli that possess β-galactosidase to produce acids and gases under their optimal growth temperature of 35–37 °C. They can be aerobes or facultative aerobes, and are a commonly used indicator of low sanitary quality of foods, milk, and water. Coliforms can be found in the aquatic environment, in soil and on vegetation; they are universally present in large numbers in the feces of warm-blooded animals as they are known to inhabit the gastrointestinal system. While coliform bacteria are not normally the cause of serious illness, they are easy to culture, and their presence is used to infer that other pathogenic organisms of fecal origin may be present in a sample, or that said sample is not safe to consume. Such pathogens include disease-causing bacteria, viruses, or protozoa and many multicellular parasites.Every drinking water source must be tested for the presence of these total coliform bacteria.

Escherichia (/ˌɛʃəˈrɪkiə/ ESH-ə-RIK-ee-ə) is a genus of Gram-negative, non-spore-forming, facultatively anaerobic, rod-shaped bacteria from the family Enterobacteriaceae. In those species which are inhabitants of the gastrointestinal tracts of warm-blooded animals, Escherichia species provide a portion of the microbially derived vitamin K for their host. A number of the species of Escherichia are pathogenic. The genus is named after Theodor Escherich, the discoverer of Escherichia coli. Escherichia are facultative aerobes, with both aerobic and anaerobic growth, and an optimum temperature of 37 °C. Escherichia are usually motile by flagella, produce gas from fermentable carbohydrates, and do not decarboxylate lysine or hydrolyze arginine. Species include E. albertii, E. fergusonii, E. hermannii, E. ruysiae, E. marmotae and most notably, the model organism and clinically relevant E. coli. Formerly, Shimwellia blattae and Pseudescherichia vulneris were also classified in this genus.

A chancre (/ˈʃæŋkər/ SHANG-kər) is a painless genital ulcer most commonly formed during the primary stage of syphilis. This infectious lesion forms around 21 days after the initial exposure to Treponema pallidum, the gram-negative spirochaete bacterium causing syphilis, but can range from 10 to 90 days. Without treatment it may persist for two to six weeks before healing. Chancres transmit syphilis through direct physical contact. These ulcers usually form on or around the anus, mouth, penis and vulva.

Chancres are also associated with the African trypanosomiasis (sleeping sickness), surrounding the area of the tsetse fly bite.

Bdellovibrio is a genus of gram-negative, obligate aerobic bacteria. One of the more notable characteristics of this genus is that members can prey upon other gram-negative bacteria and feed on the biopolymers, e.g. proteins and nucleic acids, of their hosts. They have two lifestyles: a host-dependent, highly mobile phase, the "attack phase", in which they form "bdelloplasts" in their host bacteria; and a slow-growing, irregularly shaped, host-independent form.

Alphaproteobacteria or α-proteobacteria, also called α-Purple bacteria in earlier literature, is a class of bacteria in the phylum Pseudomonadota (also called "Proteobacteria"). The Magnetococcales and Mariprofundales are considered basal or sister to the Alphaproteobacteria. The Alphaproteobacteria are highly diverse and possess few commonalities, but nevertheless share a common ancestor. Like all proteobacteria, its members are gram-negative, although some of its intracellular parasitic members lack peptidoglycan and are consequently gram variable.