Food poisoning presentation

1. Food poisoning
BY- SANJU SAH
ST. XAVIERS COLLEGE, MAITIGHAR,KATHMANDU
DEPARTMENT OF MICROBIOLOGY

2. FOOD POISONING
FOOD POISOING - Food poisoning, also called foodborne illness, is illness caused by eating
contaminated food. Infectious organisms — including bacteria, viruses and parasites — or their
toxins are the most common causes of food poisoning.
 Bacteria are a common cause of foodborne illness.

3. CAUSES
 The bacteria that are most commonly implicated in gastroenteritis are:
 Salmonella
 Campylobacter
 Shigella
 Escherichia coli (especially serotype O157:H7)
 Clostridium difficile

4. POSSIBLE CONTAMINANTS

5. Contd…

6. CLINICAL MANIFESTATIONS
• The signs and symptoms of bacterial foodborne illness include digestive system complaints
and usually start within a few hours after ingestion of contaminated food. But it may take as
long as a few days for the symptoms to start,
Symptoms includes;
 Abdominal cramps
 Diarrhea
 Fever
 Nausea
 Vomiting
 Headache
 Weakness
 Abdomen is tender to touch
 Dehydration

7. LABORATORY DIAGNOSIS
1. SPECIMEN COLLECTION AND TRANSPORTATION:
Stool is the choice of specimen submitted for the diagnosis of food poisoning. Blood , food
and vomitous is also collected as specimen.
COLLECTION OF STOOL SPECIMEN:
 Stool specimen is usually collected in a sterile, wide neck, screw capped container
 Not more than 25gm of sample is collected and in case of liquid stool about 10-15 ml of
stool is collected.
 Rectal swab may also be collected in case of infants or neonates.

8. Contd…
2. TRANSPORTATION OF COLLECTED SPECIMEN:
In case of delay different types of transport media can be used:
• Alkaline peptone water (for vibrio cholera)
• Amies transport medium (for enteric organism)
• Buffered glycerine saline (all enteric organism organism except V. spp)
• Selenite F broth (for salmonella spp)

9. Contd…
3. MICROSCOPIC EXAMINATION:
Wet mount preparation is done and observed for significant number of pus cells and bacteria.
4. CULTURE:
It is done to isolate causative organism from stool in its respective culture medium.
• SS agar- for isolation of Salmonella and shigella
• KIA OR XLD – for isolation of salmonella
• MA or EMB – for the isolation of Escherichia coli
• TCBS OR TTGA – for the isolation of V.cholerae
• BA – for the isolation of Staphylococcus aureus
• Cooked meat medium – for the isolation of clostridium
Nutrient agar is used for sub-culture for all the organism from where gram staining and
biochemical test is carried out.

10. Contd…
BIOCHEMICAL TESTS-
 Cultural identification is done by using bio-chemical test.
SEROLOGY-
 Further identification of organism can be done by serology.
 Various serological test like enzyme linked immunesorbant assay (ELISA) , later agglutinatin
etc are used for identification of staphylococcal enterotoxin.
 Clostridial toxins can also be detected by ELISA.
 For serotyping of salmonella , different sets of O and H antigens are detectd by slide
agglutination test using type specific antisera.