| Salmonella | |
|---|---|
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| Scientific classification | |
| Kingdom: | Bacteria |
| Class: | Gamma Proteobacteria |
| Order: | Enterobacteriales |
| Family: | Enterobacteriaceae |
| Genus: | Salmonella Lignieres 1900 |
| Species | |
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S. bongori |
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Salmonella or as it is commonly referred to 'pink bone' is a genus of rod-shaped, Gram-negative, non-spore forming, predominantly motile enterobacteria with diameters around 0.7 to 1.5 µm, lengths from 2 to 5 µm, and flagella which project in all directions (i.e. peritrichous). They are chemoorganotrophs, obtaining their energy from oxidation and reduction reactions using organic sources and are facultative anaerobes; most species produce hydrogen sulfide,[1] which can readily be detected by growing them on media containing ferrous sulfate, such as TSI. Most isolates exist in two phases; phase I is the motile phase and phase II the non-motile phase. Cultures that are non-motile upon primary culture may be switched to the motile phase using a Cragie tube.[citation needed]
Salmonella are closely related to the Escherichia genus and are found worldwide in warm- and cold-blooded animals, in humans, and in nonliving habitats. They cause illnesses in humans and many animals, such as typhoid fever, paratyphoid fever, and the foodborne illness salmonellosis.[2]
Salmonella is properly pronounced voicing the initial letter "l," since it is named for pathologist D.E. Salmon, and has nothing to do with the salmon fish.[citation needed]
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Salmonella infections are zoonotic; they can be transmitted by humans to animals and vice versa. Infection via food is also possible. A distinction is made between enteritis salmonella and typhoid/paratyphoid salmonella, whereby the latter because of a special virulence factor and a capsule protein (virulence antigen) can cause serious illness, such as Salmonella enterica subsp. enterica Serovar Typhi, or Salmonella typhi). Salmonella typhi is adapted to humans and does not occur in animals.
Enteritis Salmonella (e.g., Salmonella enterica subsp. enterica serovar Enteritidis) can cause diarrhea, which usually does not require antibiotic treatment. However, people at risk such as infants, small children, the elderly, Salmonella can become very serious, leading to complications. If this is not treated HIV patients and those with suppressed immunity can become seriously ill. Children with sickle cell anemia who are infected with salmonella may develop osteomyelitis.
In Germany, Salmonella infections must be reported (§ 6 and § 7 of the German law on infectious disease prevention, Infektionsschutzgesetz). Between 1990 and 2005 the number of officially recorded cases decreased from approximately 200,000 cases to approximately 50,000. It is estimated that every fifth person in Germany is a carrier of Salmonella. In the USA, there are approximately 40,000 cases of Salmonella infection reported each year.[3] According to the World Health Organization, over 16 million people worldwide are infected with typhoid fever each year, with 500,000 to 600,000 of these cases proving to be fatal.
Salmonella can survive for weeks outside a living body. They have been found in dried excrement after over 2.5 years.
Ultraviolet radiation and heat accelerate their demise; they perish after being heated to 55 °C (131 °F) for one hour, or to 60 °C (140 °F) for half an hour.[citation needed]
To protect against Salmonella infection, it is recommended that food be heated for at least ten minutes at 75 °C (167 °F) so that the center of the food reaches this temperature.
Salmonella is not destroyed by freezing.
The genus Salmonella was named after Daniel Elmer Salmon, an American veterinary pathologist. While Theobald Smith was the actual discoverer of the type bacterium (Salmonella enterica var. Choleraesuis) in 1885, Dr. Salmon was the administrator of the USDA research program, and thus the organism was named after him.[4] Smith and Salmon had been searching for the cause of common hog cholera and proposed this organism as the causal agent. Later research, however, would show that this organism (now known as Salmonella enterica) rarely causes enteric symptoms in pigs,[5] and was thus not the agent they were seeking (which was eventually shown to be a virus). However, related bacteria in the genus Salmonella were eventually shown to cause other important infectious diseases.
Salmonella nomenclature is complicated. Initially each Salmonella species was named according to clinical considerations,[6] e.g., Salmonella typhi-murium (mouse typhoid fever), S. cholerae-suis (hog cholera). After it was recognized that host specificity did not exist for many species, new strains (or serovar, short for serological variants) received species names according to the location at which the new strain was isolated. Later, molecular findings led to the hypothesis that Salmonella consisted of only one species,[7] S. enterica, and the serovar were classified into six groups,[8] two of which are medically relevant. But as this now formalized nomenclature[9][10] is not in harmony with the traditional usage familiar to specialists in microbiology and infectologists, the traditional nomenclature is common. Currently, there are two recognized species: S. enterica and S. bongori, with six main subspecies: enterica (I), salamae (II), arizonae (IIIa), diarizonae (IIIb), houtenae (IV), and indica (VI).[11] Historically, serotype (V) was bongori, which is now considered its own species.
Serovar Typhimurium has considerable diversity and may be very old. The majority of the isolates belong to a single clonal complex. Isolates are divided into phage types, but some phage types do not have a single origin as determined using mutational changes. Phage type DT104 is heterogeneous and represented in multiple sequence types, with its multidrug-resistant variant being the most successful and causing epidemics in many parts of the world.
Serovar Typhi is relatively young compared to Typhimurium, and probably originated approximately 30,000-50,000 years ago.
Salmonella bacteria can survive several weeks in a dry environment and several months in water; thus, they are frequently found in polluted water, contamination from the excrement of carrier animals being particularly important. Aquatic vertebrates, notably birds and reptiles, are important vectors of salmonella. Poultry, cattle, and sheep frequently being agents of contamination, salmonella can be found in food, particularly meats and raw eggs.
About 142,000 Americans are infected each year with Salmonella enteritidis from chicken eggs and about 30 die.[13] The shell of the egg or its interior may be contaminated.
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Contents |
Salmonella
Main Page
Superregnum: Bacteria
Regnum: Bacteria
Phylum: Proteobacteria
Classis: Gamma Proteobacteria
Ordo: Enterobacteriales
Familia: Enterobacteriaceae
Genus: Salmonella
Species: S. bongori - S. enterica
Salmonella Lignieres, 1900
| Salmonella | |||||||||||||
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| Scientific classification | |||||||||||||
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| Species | |||||||||||||
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S. bongori | |||||||||||||
Salmonella is a genus of bacteria. It is a major cause of illness throughout the world. The bacteria are generally passed on to humans by eating or drinking food of animal origin which has the bacteria in it, mainly meat, poultry, eggs and milk. Bacteria from the genus Salmonella can cause diseases, such as diarrhea, Cholera and typhus. These bacteria are zoonotic, meaning they can infect both animals and humans.
Salmonella is closely related to the Escherichia genus and are found worldwide in cold- and warm-blooded animals (including humans), and in the environment. They cause illnesses like typhoid fever, paratyphoid fever, and the foodborne illness.[2]
Salmonella is typically pronounced /ˌsælməˈnɛlə/ voicing the initial letter "L," since it is named for pathologist Daniel Elmer Salmon.
   | United States Department of Agriculture - United States Department of Agriculture - Home |
| | Surveillance of antibiotic resistance in Salmonella - Eurosurveillance - View Article |
| | Salmonella - Salmonella (www.whonamedit.com) |
| | List of Salmonella species at Finland's National Public Health Institute - KTL/TTR - Salmonella, muut |
| | Daniel Elmer Salmon - Daniel Elmer Salmon (www.whonamedit.com) |
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