Bacillus cereus
| A | Rotavirus and Norwalk virus | |
| B | Shigella and Salmonella | |
| C | S. aureus and Bacillus cereus | |
| D | Bacillus cereus and Clostridium perfringens |
| A | Rotavirus and Norwalk virus | |
| B | Shigella and Salmonella | |
| C | S. aureus and Bacillus cereus | |
| D | Bacillus cereus and Clostridium perfringens |
Bacillus cereus and Clostridium perfringens
Bacillus cereus strains can produce two different toxins: a heat stable toxin that can lead to an illness after 2 to 7 hours and a heat-labile toxin that causes disease manifestations 8 to 14 hours after ingestion. The syndrome of Clostridium perfringens diarrhea usually occurs 8 to 14 hours after ingestion of the preformed toxin.
| A | Staphylococcus aureus | |
| B | Bacillus cereus | |
| C | Salmonellosis | |
| D | Vibrio cholera |
Bacillus cereus
A child developed symptoms of food poisoning after 4 hours of ingestion of fried rice. Bacillus cereus was suspected. Which among the following is TRUE about the symptoms of Bacillus cereus food poisoning in this case?
| A |
Absence of vomiting |
|
| B |
Absence of diarrhea |
|
| C |
Presence of abdominal pain |
|
| D |
Presence of fever |
Here are two distinct types of food poisoning caused by Bacillus cereus:
- One has a short incubation period (4 hours); heat-stable toxin is the cause; consists primarily of nausea and vomiting, mild diarrhea, similar to staphylococcal food poisoning;
- Other has a long incubation period (18 hours); heat-labile enterotoxin is the cause; features include watery, nonbloody diarrhea, abdominal cramps, resembling clostridial gastroenteritis.
- Bacillus cereus, a gram-positive, spore-forming bacillus.
- The organisms that produce the vomiting syndrome have largely been associated with ingestion of rice, notably fried rice.
- The spores germinate and toxin is produced causing symptoms.
- The organisms that produce the diarrheal syndrome have been associated with contaminated meats, sauces, and dairy products.
| A |
Staph aureus |
|
| B |
Bacillus cereus |
|
| C |
Vibrio parahemolyticus |
|
| D |
Yersinia |
Ans. is ‘b’ i.e., Bacillus cereus
Bacillus cereus
. It is an important cause of food poisoning.
. Gram positive
Motile by peritrichous flagella
. Spore forming
. Culture media – Mannitol – egg yolk – Phenol-red polymyxin agar (MYPA)
| A | 1-6 hrs | |
| B |
8-16 hrs |
|
| C |
24 hrs |
|
| D |
a and b |
Ans. is. ‘a’ i.e., 1-6 hrs & ‘b’ i.e., 8-16 hrs
. Incubation period of emetic type of food poisoning —> 1-5 hours
. Incubation period of diarrheal type of food poisoning —> 8-16 hours
Characteristic of Bacillus cereus food poisoning is‑
| A | Presence of fever | |
| B | Presence of pain in abdomen | |
| C |
Absence of vomiting |
|
| D |
Absence of diarrhoea |
Ans. is ‘b’ i.e., Presence of pain in abdomen
. Bacillus cereus causes two types of food poisoning :-
i) Emetic type :- characterised by nausea, vomiting and diarrhoea
ii) Diarrhoea’ type :- characterised by abdominal cramps and diarrhoea.
| A | Shigella | |
| B |
B. Cereus |
|
| C |
Salmonella |
|
| D |
Y. enterocolitica |
Answer is B (B. cereus)
Bacillus cereus causes non invasive diarrhea due to preformed enterotoxins Shigella, Salmonella and Y. enterocolitica are causes of invasive diarrhea.
A person has episodes of vomiting 6 hrs after consuming milk. Organism responsible for this may be:
March 2009
| A |
Clostridium perfringenes |
|
| B |
Bacillus cereus |
|
| C |
Salmonella typhi |
|
| D |
Staphylococcus |
Ans. B: Bacillus cereus and D: Staphylococcus
Incubation period of food poisoning due to:
- Clostridium perfringenes: 6-24 hours
- Bacillus cereus-It produces atleast 2 distinct enterotoxins. One, the emetic form with a short incubation period (1-6 hours) characterized by predominantly upper gastrointestinal tract symptoms, rather like staphylococcal food poisoning. The other, the diarrheal form, with a longer incubation period (12-24 hours) characterized by predominantly lower intestinal symptoms like clostridium perfringenes food poisoning. The toxins are preformed and stable.
- Salmonella typhi- 12-24 hours
- Staphylococcus- 1-6 hours. The incubation is short because of preformed toxins.
