Salmonella enterica, bacterium, SEM

Coloured scanning electron micrograph (SEM) of Salmonella enterica, Gram-negative, flagellated, enteric, rod prokaryote (dividing). Salmonella enterica (formerly known as Salmonella choleraesuis) has over 2000 serovars or strains. S. enterica can be transmitted by human faeces via contaminated water, food, or by person to person contact. Most cases of salmonellosis are caused by food infected with S. enterica. S. enterica often infects cattle and poultry, as well as other domestic animals such as cats and hamsters that can transmit infections to humans. Salmonella typhi is a serovar of Salmonella enterica that has been elevated to species status and causes the human disease typhoid fever. Other serovars such as 'typhimurium' (now known as Salmonella typhimurium) can also lead to a form of human gastroenteritis referred to as salmonellosis. Magnification: x2,225 when shortest axis printed at 25 millimetres.