Immunology/Infection Flashcards
How many bacteria are there in the stomach, small intestine and large intestine respectively?
Stomach - should be sterile
Small intestine - Low bacterial numbers
Large intestine - Lots of bacteria
Most bacteria in the stomach are commensals or symbiotes, what is a commensal and a symbiote?
Commensal - One organism benefits and the other is unaffected
Symbiosis - Both organisms benefit
Two types of Gi infections?
Intra-luminal: ingestion of exogenous pathogen
Extra-luminal: Spillage of endogenous bacteria (so commensals)
Common pathogens that cause oesophagitis?
Candida
CMV
HSV (herpes simplex)
Symptoms of community acquired infantile diarrhoea, and most common causative organism?
Poor feeding, irritable
Watery stool
Failure to thrive
E.coli, rotavirus, adenovirus
What is cryptosporidium parvum, what symptoms does it cause, who is at risk?
Protozoa
Watery diarrhoea
Normally self-limiting but in immunocompromised can lead to severe condition/death
What is Bacillus cereus, two main causes?
Bacterium, the toxin causes food poisoning
Re-heated cooked rice
Enetrotoxins from variety of foods
Two different types of salmonella infections?
Non-typhoidal, rarely systemic, antibiotics sometimes required
Typhoidal: always systemic, always need antibiotic
Two strains of typhoidal salmonella that can cause invasive gastroenteritis?
Salmonella Typhi
Salmonella Paratyphi
Actions in hospital acquired diarrhoea?
Isolate immediately
Acute diarrhoea definition?
Diarrhoea for less than 4 weeks
Factors that mean you should investigate diarrhoea further?
Recent hospitalisation > a week Travel Blood in stool Dehydration/weight loss High inflammatory markers
Microscopic examination techniques for stool samples?
- Saline wet mount: Worm eggs/larvae, protozoa and cysts
2. Iodine wet Mount: Used to stain nuclei/glycogen of cysts
Other lab techniques used for diagnosis of stool samples?
PCR
ELISA
What percentage of infective diarrhoea’s are caused by viruses?
90%
