Salmonella enterica: Difference between revisions
imported>Debra B. Sherman |
imported>Chris Day No edit summary |
||
| Line 1: | Line 1: | ||
{{subpages}} | {{subpages}} | ||
{{EZarticle-closed-auto}} | {{EZarticle-closed-auto}} | ||
Revision as of 14:43, 26 March 2008
 Articles that lack this notice, including many Eduzendium ones, welcome your collaboration! |
Classification
Higher order taxa
Bacteria; Proteobacteria; Gammaproteobacteria; Enterobacteriales; Enterobacteriaceae
Species
Salmonella enterica
Description and significance
The Salmonella bacteria were first discovered by an American scientist, Dr. Daniel E. Salmon in 1884. Dr. Salmon isolated the bacteria from the intestines of a pig and called it Salmonella choleraesui. The genus Salmonella is divided into two species, S. enterica and S. bongori. Salmonella enterica are rod shaped gram-negative bacteria. They are very commonly found in raw meat, chicken, and egg shells. Another one of its' habitats is in contaminated water.Once it enters the host, it resides in the intestinal tract of the human or animal. Research done on the genomic sequencing of S. enterica can aid in the effectiveness of medications and vaccinations in treating disease. It is usually isolated on a selective medium such as Maconkey agar, XLD agar, XLT agar, or DCA agar. The three main serovars of Salmonella enterica are Typhi, Typhimurium, and Enteritidis. Their DNA are anywhere between 95% and 99% similar. Ways that researchers have used to differentiate between the different serovars is by looking at their phage specifity. S. typhi is the serovar responsible for typhoid fever, a lethal disease. This disease is usually found in poor, under developed areas. The most common symtoms are fever, vomiting and possible death. S. typhi is found in contaminated water. A human can become infected by drinking the contaminated water or even by washing other foods with the water. S. typhimurium used to be the most common cause of food poisining. It has many of the similar symptoms as S. typhi although not usually fatal. Humans with a weak immune system may require antiobiotics as treatment. S. enteritidishas recently become the most common cause of food poisoning and gives rise to the same symtoms as S. typhimurium. Additionally, it infects and spreads through flocks of chickens. This causes the Salmonella infection to affect the human intestines once the chicken has been ingested.
Genome structure
Describe the size and content of the genome. How many chromosomes? Circular or linear? Other interesting features? What is known about its sequence? Does it have any plasmids? Are they important to the organism's lifestyle?
Cell structure and metabolism
S. enterica is a motile, rod shaped bacteria that contain flagella.
Ecology
Describe any interactions with other organisms (included eukaryotes), contributions to the environment, effect on environment, etc.
Pathology
Different species of Salmonella can cause a wide range of diseases from gastrointestinal problems to typhoid fever. Usually the strain can be carried in a large range hosts including humans, animals, rodents, and birds. S. typhi, a serovar of S. enterica, will only infect humans. The typhoid fever that it causes kills 500,000 people per year. Other serovars like S. typhimurium infect humans, as well as many other mammalian species. The bacteria enters the host by disturbing the membrane. Once inside, it harms the host by causing the levels of intracellular free calcium to increase and disorganizing the cytoplasm of the cell. Symptoms usually include diarrhea, fever, and abdominal cramps. Strains that are associated with food-borne infections are usually not treated with antibiotics, but will resolve themselves over time. The typhoidal strains usually do require treatment by antibiotics, and possibly hospitilization. Some of the antibiotics have been used in the beef and poultry industries. This has caused for a strain of bacteria to be resistant to the antibiotics.
Application to Biotechnology
Does this organism produce any useful compounds or enzymes? What are they and how are they used?
Current Research
Enter summaries of the most recent research here--at least three required