1. Clostridial infections *C.difficile is found as a part the normal bowel flora in 3-5% of the pooulation and even more commonly in hospitalized patients. *C. difficile produces two toxins : toxin A is an enterotoxin and toxin B is cytotoxic and causes blioody diarrhoea. *It usually causes illness after other bowel commensals have been eliminated by antibiotic therapy.

2. *Almost all antibiotics have been linked with C. difficile diarrhoea, which can begin anything from 2 days to a month after taking antibiotics.Elderly hospitalized patients are most frequently been affected. *Symptoms can ranged from mild diarrhoea to haemorrhagic colitis.Sometimes the ulcerated colonic mucosa may be covered by a membrane – like material ( pseudomembraneous colitis ).

3. *The diagnosis is made by detecting A or B toxins in the stools by ELISA techniques. *Treatment is with metronidazole 400 mg three times daily or oral vancomycin 125 mg four times daily ; causative antibiotics should be discontinued if possible. *The disease is usually more severe in the elderly, and can cause intractable diarrhoea leading to death.

4. Clostridium perfringens : infection is due to inadequately cooked food, usually meat or poultry allowed to cool for a long time during which the spores germinate. *The ingested organism produces enterotoxin causing watery diarrhoea with severe abdominal pain, usually without vomiting.

5. Traveller ‘ s diarrhoea *Defined as the passage of three or more unformed stools per day in a resident of an industrialized country travelling in a developing nation. *Infection is usually food – oo water- borne, and younger travellers are most often affected ( probably reflecting behaviour patterns )

6. *The disease is usually benign and self- limiting: treatment with quinolone antibiotics may hasten recovery but is not normally necessary. *Prophylactic antibiotic therapy may also be effective for short stays, but should not be used routinely. The common causative organisms are : ETEC 3o-70% Shigella 0-15% Salmonella 0-10% Campylbact. 0-15% Viral pathogens 0-10% Giardia intestinalis 0-3%

7. Food poisoning *Defined as : ‘any disease of an infective or toxic nature caused by or thought to be caused by the consumption of food and water ‘. *Not all cases of gastroenteritis are food poisoning, as the pathogens are not always food – or water- borne.