Salmonella is a gram-negative, rod-shaped (bacillus) bacteria genus that belongs to the family Enterobacteriaceae. Salmonella contains two species: Salmonella enterica and Salmonella bongori. The type species is Salmonella enterica (S. enterica), which is widely found in warm-blood animals all over the world. Salmonella enterica can be further catalogued into 6 subspecies, with more than 2,500 serotypes. Salmonella bongori (S. bongori), however, is restricted to cold-blooded animals, particularly reptiles. Species of Salmonella are facultative intracellular pathogens. They can infect many different animal species, including humans. Thus they can be transfered between human and other animals. Salmonella infection may cause illness such as salmonellosis (food poisoning), typhoid fever, and paratyphoid fever.