General Information: Edwardsiella tarda is a Gram-negative member of the normal gut microflora of fish, humans, chickens and other animals. This organism is also a serious pathogen of marine and freshwater fish and has been isolated from channel catfish, Japanese eels, flounder, tilapia, and other economically important fish. Infection by this organism is characterized by septicemia, internal abscesses, and skin lesions. This disease is often associated with poor water quality and mortality in aquaculture can be high. Edwardsiella tarda also causes opportunistic infections in humans, most commonly gastroenteritis and wound infections. However, this organism has been isolated from cases of septicemia and meningitis, primarily in immunocompromised patients.