User:Nathalie.solorzano/sandbox

Salmonella is a genus of facultative anaerobic Gram-negative rod-shaped (bacillus) bacteria of the family Enterobacteriaceae. The two species of Salmonella are Salmonella enterica and Salmonella bongori. S. enterica is the type of species and is further divided into six subspecies (enterica, salamae, arizonae, diarizonae, houtenae and indica) that include over 2,600 serotypes. S. bongori is predominantly associated with cold-blooded animals. Salmonella was named after Daniel Elmer Salmon (1850–1914), an American veterinary surgeon.

Salmonella History

Salmonella was first discovered in 1885 where the strain enterica was isolated from the intestine of a pig by Dr. Salmon. Salmonella is usually found in the digestive tracts of livestock and can commonly affect meat, poultry, eggs and unpasteurized dairy products. An infection can last up to 7 days with unpleasant and potentially serious symptoms including stomach cramps, headaches, vomiting and diarrhea.

Salmonella Nomenclature Salmonella nomenclature is complex, and scientists use different systems to refer to and communicate about this genus. The nomenclature for the genus Salmonella has evolved from the initial one serotype-one species concept proposed by Kauffmann on the basis of the serologic identification of O (somatic) and H (flagellar) antigens.

Adding a table with the number of serotypes within each subspecies would be helpful, as well as the usual habitat in which each subspecies is found in.

Salmonella Outbreaks

Salmonella is an important bacterial genus that can cause the most common forms of food poisoning worldwide. Throughout history typhoid fever – caused by Salmonella – triggered many dire outbreaks, and people eventually recognized the link between this disease and contaminated food or beverages. Karl Joseph Eberth, a doctor and student of Rudolf Virchow, discovered the bacillus in the abdominal lymph nodes and the spleen in 1879.

Over the past years Salmonella outbreaks have been linked to food, animals, and other sources (the most common being food). The Centers for Disease Control and Prevention traces outbreaks back from 2006 that were found on tomatoes (see tables). The Centers for Disease Control and Prevention began tracking outbreaks starting in the 1970s. By 2012, the figures were roughly 130,000 hospitalizations and 3,000 deaths.

Salmonella is one of the most common intestinal infections reported in the United States. Salmonella infection occurs when the bacteria are ingested, typically from food derived from infected food-animals, but it can also occur by ingesting the feces of an infected animal or person. Food sources include raw or undercooked eggs/egg products, raw milk or raw milk products, contaminated water, meat and meat products, and poultry. Raw fruits and vegetables contaminated during slicing have been implicated in several food borne outbreaks. Salmonellosis (the disease caused by Salmonella) is the second most common food borne illness after Campylobacter infection. Campylobacter contaminates most chickens that go to market in the United States, and the bacteria are the most common cause of food-borne illnesses, adding about two million cases of food poisoning in the country annually. It is estimated that 1.4 million cases of salmonellosis occur each year in the U.S.; 95% of those cases are food borne related.

Food borne illness is caused by food contaminated with pathogenic microorganisms or toxic substances. Most food borne outbreaks of norovirus illness are likely to arise though direct contamination of food by a food handler immediately before its consumption. Approximately 220 of each 1000 cases of Salmonellosis result in hospitalization and eight of every 1000 cases result in death. About 500 to 1,000 or 31% of all food-related deaths are caused by Salmonella infections each year. Salmonella investigated outbreaks linked to food, by year, according to the Centers for Disease Control and Prevention (CDC). Salmonella investigated outbreaks linked to animals, by year, according to the Centers for Disease Control and Prevention (CDC).

Salmonella investigated outbreaks linked to other sources, by year, according to the Centers for Disease Control and Prevention (CDC).

Salmonella Adaptations/ Immunity

The analysis of virulence factors used by different Salmonella serotypes can serve as a powerful model for studying mechanisms of host adaptation because these pathogens are physiologically well characterized and lend themselves to genetic analysis. However, they differ greatly with regard to host range and their degree of host adaptation. Salmonella serotypes are closely related as shown by analysis of orthologous genes.

When referring to host adaptations in Salmonella, it is described as the "ability of a pathogen to circulate and cause disease in a particular host population. Another usage of host adaptation in terms of Salmonella, refers to the evolution of a pathogen such that it can infect, cause disease, and circulate in another host species.

A study conducted shows that Salmonella enterica has adapted to survive bile. Such adaptations have been linked to multiple changes in gene expression, which include upregulation of the RpoS-dependent general stress response and other stress responses.

Salmonella Preventions

Avoiding raw eggs or undercooked beef, pork, or poultry can reduce the risk on Salmonella. Refrigerating food properly, both before cooking it and after serving it is also really important to ensure that bacteria doesn't grow. Washing your hands before, and after, handling food can also reduce the risk as Salmonella can spread from animals to people and from people to people.