Salmonella sp.
General: Comprised of only two species, but they have > 2,400 antigenically distinct serotypes; these serotypes have been commonly described as their own species, such as Salmonella typhi, but strictly speaking are better termed Salmonella serotype Typhi. Most infections from contaminated food (especially eggs) or water, but may be from colonized animals or humans. Infection usually self-limited in immunocompetent patient, with diarrhea up to 1 week.
Resistance:
Growth characteristics: Urease-. MacConkey agar and either HE or XLD agars are generally recommended, but more selective media include xylose-lysine-Tergitol 4 agar and Rambach agar, for isolation of Salmonella sp. Bismuth sulfite agar and brilliant green agar are preferred for isolation of Salmonella serotype Typhi. Suspicious colonies subcultured onto TSI or Kligler iron agar slants; most serotypes produce alkaline reaction on the slant and acidic reaction in the butt (ALK/A), as well as gas and H2S.
Common pathogens: