<unk>  is a rod-shaped, facultative intracellular, gram-negative enterobacteria.<unk>  species shows motility, produces hydrogen sulfide, and only 1% is able to ferment lactose. It may be isolated from the stool of infected patients, and grown in culture media, such as MacConkey agar and deoxycholate agar.<unk>  enters the body through contaminated food or water, and invades the intestinal epithelial cells, causing inflammation.
This bacterium may be classified into 2 different species:<unk>  enterica and<unk>  bongori.<unk>  enterica is divided in 6 different subspecies, of which I, contains most pathogenic serotypes for humans.<unk>  may be serogrouped into more than 2500 serovars with polyvalent antisera, according to the capsular antigen, polysaccharide O antigens, and flagellar antigens. The bacteria show tropism for the epithelial cells of the gastrointestinal tract, macrophages, dendritic cells, and neutrophils. Different serotypes of<unk>  may have different natural reservoirs, some have humans as their only natural reservoir (serotypes Sendai and Typhi), while others (serotype Dublin) may infect humans and cattle.
Salmonella
Yersinia
Shigella
Clostridium difficile
Campylobacter jejuni
Vibrio cholerae
Listeria
Bacteroides