General characteristics of salmonella species

Salmonella grows in the temperature range of 2-47° C with rapid growth between 25 and 43° C. The minimum temperature for growth prevails at neutral pH and increases sharply with increasing acidity or alkalinity of the suspending medium.

The species are facultatively anaerobic, Gram-negative, straight, small (0.7-1.5 x 2. 0– 5. 0 μm) rods, which are usually motile with peritrichous flagella.

Salmonella species cause illness by means of infection, i.e. the organism grows and multiples in the host’s body and becomes established in or on the cells or tissue of the host.

Salmonella typhi

Salmonella multiply in the small intestine, colonizing and subsequently invading the intestinal tissues, producing an enterotoxin and causing an inflammatory reaction and diarrhea.

Cell envelope of Salmonella spp. consists of a complex lipopolysaccharide structure, which may function an an endotoxins. Once ingested, Salmonella viable cell are colonized in ileum and colon, by binding on the surface of epithelial cell an using type III secretion system to inject effector proteins directly into the host cell cytoplasm.
General characteristics of salmonella species