• Salmonella

Salmonella 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, 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.

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.

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

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.

Sources

• Unclean food, particularly in institutional kitchens and restaurants
• Excretions from either sick or infected but apparently clinically healthy people and animals (especially endangered are caregivers and animals)
• Polluted surface water and standing water (such as in shower hoses or unused water dispensers)
• Unhygienically thawed fowl (the meltwater contains many bacteria)
• An association with reptiles (pet tortoises and snakes) is well described.
• 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.

from Wikipedia