Age of patients: may affect any age but many patients are children
Epidemiology:
(1) may be endemic in a population, usually in the tropics
(2) tends to be more common during hot weather
Clinical features:
(1) watery diarrhea typically lasting 3 days
(2) abdominal pain
(3) tenesmus
(4) dehydration
(5) often afebrile
(6) evidence of a colitis may last up to 3 weeks
Laboratory findings:
(1) neutrophils in smears from the stool
(2) exclusion of other causes for colitis
Definitive diagnosis usually requires specialized testing that is not readily available. This may involve:
(1) molecular analysis of Bacteroides fragilis species isolated from the stool (PCR for bft gene)
(2) toxin analysis (cell assay with and without neutralizing antibody)
(3) demonstration of anti-toxin antibodies.
