Aeromonas hydrophila and Plesiomonas shigelloides as Causes of Intestinal Infections

Infections due to Aeromonas hydrophila and Plesiomonas shigelloides in immunocompromised hosts have been well documented, but the role of these organisms in causing gastrointestinal disease in healthy persons is controversial. Despite difficulties in characterizing the exotoxins produced by Aeromonas species, there is accumulating evidence that these bacteria are capable of causing usually mild, self-limited diarrheal disease in previously healthy adults. Some pediatric patients may have protracted dysenteric symptoms. P. shigelloides, an organism closely related to Aeromonas species, may also cause diarrhea in the healthy host, but no exotoxins have yet been identified by the assays used to identify other bacterial enterotoxins. Replacement of fluid and electrolytes is the basis of treatment, and antimicrobial agents should be reserved for patients with chronic or serious illness, or for those at particular risk of serious illness (hepatobiliary disease, septicemia, neoplasms).