B. cereus can produce either a syndrome with a short incubation period— the emetic form, mediated by a staphylococcal type of enterotoxin—or one with a longer incubation period (8–16 h)—the diarrheal form, caused by an enterotoxin resembling E. coli LT, in which diarrhea and abdominal cramps are characteristic but vomiting is uncommon. The emetic form of B. cereus food poisoning is associated with contaminated fried rice; the organism is common in uncooked rice, and its heat-resistant spores survive boiling. If cooked rice is not refrigerated, the spores can germinate and produce toxin. Frying before serving may not destroy the. | Chapter 122. Acute Infectious Diarrheal Diseases and Bacterial Food Poisoning Part 8 B. cereus can produce either a syndrome with a short incubation period the emetic form mediated by a staphylococcal type of enterotoxin or one with a longer incubation period 8-16 h the diarrheal form caused by an enterotoxin resembling E. coli LT in which diarrhea and abdominal cramps are characteristic but vomiting is uncommon. The emetic form of B. cereus food poisoning is associated with contaminated fried rice the organism is common in uncooked rice and its heat-resistant spores survive boiling. If cooked rice is not refrigerated the spores can germinate and produce toxin. Frying before serving may not destroy the preformed heat-stable toxin. Food poisoning due to Clostridium perfringens also has a slightly longer incubation period 8-14 h and results from the survival of heat-resistant spores in inadequately cooked meat poultry or legumes. After ingestion toxin is produced in the intestinal tract causing moderately severe abdominal cramps and diarrhea vomiting is rare as is fever. The illness is self-limited rarely lasting 24 h. Not all food poisoning has a bacterial cause. Nonbacterial agents of shortincubation food poisoning include capsaicin which is found in hot peppers and a variety of toxins found in fish and shellfish Chap. 391 . Laboratory Evaluation Many cases of noninflammatory diarrhea are self-limited or can be treated empirically and in these instances the clinician may not need to determine a specific etiology. Potentially pathogenic E. coli cannot be distinguished from normal fecal flora by routine culture and tests to detect enterotoxins are not available in most clinical laboratories. In situations in which cholera is a concern stool should be cultured on thiosulfate-citrate-bile salts-sucrose TCBS agar. A latex agglutination test has made the rapid detection of rotavirus in stool practical for many laboratories while reverse-transcriptase polymerase chain .
