Diseases & National Health Programme
All are Characteristic of Bacillus cereus food poisoning except (DNB Dec 09)
|B|| Pain abdomen|
Fever is not a characteristic feature of B.cereus food poisoning, although is has very short IP of 1-6 hrs & vomiting with abdominal cramps is the predominant feature. Diarrhoea usually follows the vomiting episodes.
Cereus Food Poisoning –
a. Bacillus cereus is an aerobic, spore-bearing, motile, gram positive rod. It is ubiquitous in soil, and in raw, dried and processed foods. The spores can survive cooking and germinate and multiply rapidly when the food is held at favourable temperatures. B. cereus has been recognised as a cause of food poisoning, with increasing frequency in recent years.
b. Recent work has shown that B. cereus produces at least 2 distinct enterotoxins, causing 2 distinct forms of food poisoning. One, the emetic form with a short incubation period (1-6 hours) characterised by predominantly upper gastrointestinal tract symptoms, rather like staphylococcal food poisoning. The other, the diarrhoeal form, with a longer incubation period (12-24 hours) characterised by predominantly lower intestinal tract symptoms like C/ perfringens food poisoning (diarrhoea, abdominal pain, nausea with little or no vomiting and no fever. Recovery within 24 hours is usual). The toxins are preformed and stable.
c. Diagnosis can be confirmed by isolation of 105 or more B. cereus organisms per gram of epidemiologically incriminated food. Treatment is symptomatic.
Some important facts about other types of food poisoning are mentioned below: