Salmonella sp. Coloured transmission electron micrograph (TEM) of a cluster of Salmonella sp. bacteria. The cells are rodshaped with long hair like flagellae. The cell at centre is undergoing cell division whilst the cells at centre left have just completed division. Salmonella bacteria belong to the Enterobacteriaceae family. They are Gramnegative bacilli bacteria that inhabit the human gut. Salmonella includes serotypes responsible for typhoid, paratyphoid fever, gastroenteritis, or food poisoning. Around 1800 serotypes have been identified. negatively stained. Magnification unknown.