Aeromonas and plesiomonas as possible causes of diarrhoea.

The number of reports on the isolation of Aeromonas from patients with diarrhoeal disease is now large and suggests an etiological role of the bacterium. It is well established that strains of Aeromonas produce an enterotoxin. This enterotoxin is cytotonic, i.e. it does not damage the membrane, and it does not cross-react immunologically with cholera toxin and Escherichia coli heat-labile (LT) toxin. Most enterotoxigenic strains also produce a cytotoxic protein (hemolysin), the role of which is probably limited in diarrhoea but potentially toxic in humans in other kinds of infections. Strains of Plesiomonas shigelloides also seem to be able to cause diarrhoea in some cases. The pathogenesis of Plesiomonas-induced diarrhoea remains to be elucidated, but a heat-stable enterotoxin may be involved.