Caption

Coloured scanning electron micrograph (SEM) of Aeromonas hydrophila, Gram-negative, facultatively anaerobic, oxidase positive, rod bacterium (prokaryote). A. hydrophila is a bacterium that occurs in all types of aquatic environments. It is motile by polar flagella and can survive in aerobic and anaerobic environments. A. hydrophila causes diseases especially in freshwater fish including tail rot, fin rot, red fin disease and haemorrhagic septicaemia. It also causes infections in other aquatic animals such as amphibians. It produces Aerolysin Cytotoxic Enterotoxin (ACT), a toxin that can cause tissue damage. In humans Aeromonas hydrophila causes gastroenteritis. It is also associated with cellulitis, and can cause diseases such as myonecrosis and eczema in immunocompromised patients. It is resistant to certain antibiotics and chemotherapeutic agents. Magnification: x2,600 when shortest axis printed at 25 millimetres.