Plesiomonas shigelloides

P. shigelloides is a bacterium that has been isolated from freshwater, freshwater fish, and shellfish and from many types of animals including cattle, goats, swine, cats, dogs, monkeys, vultures, snakes, and toads. Most human P. shigelloides infections are suspected to be waterborne. The organism may be present in unsanitary water which has been used as drinking water, recreational water, or water used to rinse foods that are consumed without cooking or heating. The ingested P. shigelloides organism does not always cause illness. It has been found in the stools of patients with diarrhea, but is also sometimes found in healthy individuals. It cannot yet be considered a definite cause of human disease.

What are the symptoms of a P. shigelloides infection?

Gastroenteritis is the disease with which P. shigelloides has been implicated. P. shigelloides gastroenteritis is usually a mild self-limiting disease with fever, chills, abdominal pain, nausea, diarrhea, or vomiting. Symptoms may begin 20-24 hours after consumption of contaminated food or water; diarrhea is watery, non-mucoid, and non-bloody. In severe cases, diarrhea may be greenish-yellow, foamy, and blood tinged. Duration of illness in healthy people may be 1-7 days. The infectious dose is presumed to be quite high, at least greater than one million organisms.

What foods are associated with P. shigelloides infection?

Most P. shigelloides infections occur in the summer months and correlate with environmental contamination of freshwater (rivers, streams, ponds, etc.). The usual route of transmission of the organism in sporadic or epidemic cases is by ingestion of contaminated water or raw shellfish.

How common are P. shigelloids infections?

Most P. shigelloides strains associated with human gastrointestinal disease have been from stools of diarrheic patients living in tropical and subtropical areas. Such infections are rarely reported in the U.S. or Europe because of the self-limiting nature of the disease.

Is a P. shigelloids infection serious?

P. shigelloides infection may cause diarrhea of 1-2 days duration in healthy adults. However, there may be high fever and chills and protracted dysenteric symptoms in infants and children under 15 years of age. Extra- intestinal complications ( septicemia and death) may occur in people who are immunocompromised or seriously ill with cancer, blood disorders, or hepatobiliary disease.

Who is susceptible to P. shigelloides infection?

All people may be susceptible to P. shigelloides infection. Infants, children and chronically ill people are more likely to experience protracted illness and complications.