6 Gastro Intestinal infections Flashcards
Name the different MAIN structures in the GI tract
mouth
pharynx
oesophagus
stomach
small intestine
large intestine
anus
Name the different accessory structures of the GI tract
teeth
tongue
salivary glands
liver
gallbladder
pancreas
What are some way the GI tract is adapted to prevent infection and protect IN MOUTH ?
- flow of liquids
- saliva
- lysozymes
- normal bacterial flora
What are some way the GI tract is adapted to prevent infection and protect IN OESOPHAGUS?
- flow of liquids
- peristalsis
What are some way the GI tract is adapted to prevent infection and protect IN STOMACH?
- Acidic pH
What are some way the GI tract is adapted to prevent infection and protect IN SMALL INTESTINE ?
- flow of gut contents
- peristalsis
- mucus: bile
- secretory IgA
- lymphoid tissue (Peyer’s patches)
- shedding and replacement of epithelium
- normal flora
What are some way the GI tract is adapted to prevent infection and protect IN LARGE INTESTINE ?
- normal flora
- peristalsis
- shedding and replacement of epithelium
- mucus
Dysentery is defined as ..?
inflammatory disorder of the GI tract
often associated with blood and pus in faeces
accompanied by symptoms of pain, fever, abdominal cramps
usually resulting from disease of large intestine
Microbiota of the GI tract is composed of …
bacteria, viruses, fungi
Microbiota describes the ….
microbes that are normally present in and on the human body
examples of human microbiota bacteria
- firmicutes
- bacteroidetes
- actinobacteria
- proteobacteria
examples of human microbiota archaea
- methanobrevibacter
- mitrososphaera
examples of human microbiota viruses
- herpesviridae
- papillomaviridae
- polyomaviridae
- adenoviridae
examples of human microbiota eukarya
- candida
- malassezia
- saccharomyces
- cladosporium
- what does stool analysis look for ?
- It may also be used with ….. to detect parasites
- Presence of pathogenic microorganisms e.g. yeasts, parasite, bacteria.
- micrscopical analysis
Commensal bacteria are constantly breaching the epithelium barrier of the gut.
How does the gut not stay in a state of constant inflammation knowing that the gastrointestinal system is anti-inflammatory in nature ?
- commensal bacterial directly contribute to immunosuppressive environment
- macrophages inside lamina propria are non-inflammatory (don’t produce cytokines)
- IgA antibodies designed to protect mucosal surfaces and NOT produce inflammation (via transcytosis mechanisms)
- compartmentalised response = GI system is separate from systemic immune system
Transmission routes include…
- ingestion = faecal-oral / consumption of infected material e.g. food, water
- direct
- indirect
List some common oral infections
- dental decay
- gingivitis
- periodontitis
- oral herpes
- oral thrush (oral candida)
- hand, foot & mouth disease
- herpangina
Gastritis is ….
inflammation of the stomach mucosa
symptoms of gastritis
- upper abdominal pain
- indigestion
- bloating
- nausea
- vomiting
- belching
- loss of appetite
- weight loss
8 RISK FACTORS for gastritis :
- NSAIDs (nonsteroidal anti-inflammatory drugs)
- increased intake of alcohol or caffeine
- severe physiological stress
- autoimmune diseases
- Crohn’s disease
- crowded living conditions
- unsafe drinking water supply
- living with someone with a H. pylori infection
Diagnosis for gastritis includes…
- H. pylori breath test
- stool test
- blood test
- endoscopy
gastroenteritis is what ?
Inflammation of lining of the stomach and intestines
symptoms of gastroenteritis …?
- nausea
- vomiting
- diarrhoea
- abdominal cramps (dull / sharp)
- abdominal discomfort
Common symptoms of gastritis and gastroenteritis ?
- nausea
- vomiting
Gastroenteritis causes:
* …1.. agents : …2….
* not all are directly related to ..3.. within gut
* ..4… can also mediate gastrointestinal inflammation
- infectious
- parasites, viruses, bacteria
- active infection
- pre-formed toxin
overivew of Infectious and non-infectious causes of gastroenteritis
infectious = bacteria, parasites, viruses
non-infectious = food poisoning, food intoxication
what is food poisoning ?
Ingestion of pathogen / toxin leading to infection of GI tract, thought to be caused by consumption of food and water
How can food poisoning lead to gastroenteritis ?
- bacteria multiply and produce toxins within the contaminated food
- while the organisms may be destroyed during food preparation - toxins aren’t destroyed (food poisoning)
what is food intoxication ?
ingestion of preformed toxins (not infection with organism itself)
definition of diarrhoea ?
abnormal faecal discharge characterised by frequent and / or fluid stool
Diarrhoea is usually the result of the …1… and involving loss of …2..
- small intestine
- fluid and electrolyte
Diarrhoea without blood / pus is usually indicative of ….. production
enterotoxin
Diarrhoea with blood / pus is usually indicative of …
invasive infection with mucosal destruction
there are 4 groups of viruses associated with gastroenteritis , name them :
RACE
* rotovirus (groups A, B, and C)
* astroviruses
* caliciviruses (noroviruses, sapoviruses)
* enteric adenoviruses (type 40 and 41)
do bacterial or viral infections cause milder gastroenteritis ?
viral produces MILDER symtpoms which are similar to bacterial
enterocolitis definition ?
inflammation involving the mucosa of both the small and large intestine
Name some bacterial causes of dysentery
SCCS
- shigella spp
- salmonella spp
- campylobacter spp
- enteroinvasive E.coli
- enterohaemorragic E. coli
- Yesernia enterocolitica
- Vibrio parahaemolyticus
- clostridium difficile
Name some bacterial causes of watery diarrhoea
CCCV B+SS (305 buffalo’s and sheep )
& which E.coli strains
- campylobacter jejuni
- clostridium perfringens
- clostridium difficile
- vibrio cholerae
- bacillus cereus
- staphylococcus aurues
- slamonella spp
- enteroxigenic E coli
- enteropathogenic E coli
Examples of helminth infection causing gastrointestinal infections
- nematode (roundworm) infection
- enterobius vermicularis (threadworm/pinform) infection
- trematodes (flukes) infection
- cestodes (tapeworms) infection
- taenia spp (flatworms cestoda)
Give some examples of protozoal infections
- Amoebea = (Amboebiasis) entemoeba histolytica
- Flagellates = (giardiasis) giardia intestinalis
- Coccidia = (cryptosporidiosis) cryptosporidium parvum
- Ciliates = (balantidisis) balantidium coli
- Microspora =( microsporidiosis) enterocytozoon bieneusi
Bacteria that are the predominant cause of travellers’ diarrhoea ?
enterotoxigenic E.coli (ETEC)
- common bacterial cause of food poisoning
- staphyloccocus intoxication (S. aurues)
S.aurues produces …1.. which stimulate ..2.., nausea & vomiting . They are also resistent to …3.. in stomach/ small intestine
- 5 heat-stable enterotoxins (A-E)
- intestinal muscle contractions
- enzyme destruction
Which type of diarrhoea is usually the result of enterotoxin production without the presence of blood or pus ?
bacterial
Which test allows the detection and identification of pathogenic bacteria in the stool ?
1. stool observational analysis
2. microscopic analysis
3. stool culture
4. blood test
5. urine analysis
- stool culture
What is the predominant cause of traveller’s diarrhoea ?
bacterial pathogens
