False colour transmission electron micrograph (TEM) of a single bacterium, Pasteurella multocida, a member of a species of bacteria that causes haemorrhagic septicaemia and other infections in animals and humans. Such bacteria are occasionally found in wounds to humans caused by cats and dogs, having originated from the animals' mouths. The presence of Pasteurella may prevent the wound from healing; antibiotics such as penicillin may offer treatment. Pasteurella sp. has also been identified in the sputum of persons with chronic bronchial disease, but the significance of its presence here is uncertain. Magnification: X 24, 000 at 35mm size.