A group of facultative intracellular, rod-shaped, non-lactose fermenting, oxidase-negative, gram-negative bacteria that belong to the Enterobacteriaceae family. Produces endotoxin and can disseminate hematogenously. Common sources include reptiles (e.g., turtles) and raw meat, poultry, and eggs. Causes typhoid and paratyphoid fever, gastroenteritis, osteomyelitis (in patients with sickle cell disease), and reactive arthritis.