Characteristics of Salmonella Bacteria

Salmonella commonly resides in eggs
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Salmonella is genus that includes 2,300 different species of bacteria. The most common types of salmonella are Salmonella enteritidis and Salmonella typhimurium, which account for half of all human infections.

Gram Test

The Gram test determines to the composition of a bacterium's cell wall. Salmonella is gram negative, which signifies high amounts of peptidoglycan, a mesh-like substance that provides structure and strength.

Oxygen Needs

Salmonella is a facultative bacteria. This means that it can survive with or without oxygen. Obligate bacteria, on the other hand, can only survive under specific conditions.


Salmonella is a rod-shaped bacteria, or bacillus. Unlike other strains of bacilli, however, salmonella does not produce spores.

Appearance on Augur

On MacConkey agar, salmonella colonies appear colorless and transparent, though they sometimes have dark centers. A colony is a group of bacteria that are growing together.


Salmonella causes two diseases in humans: Enteric fever, or typhoid, and gastroenteritis. Doctors refer to both diseases as "salmonellosis"