Bacteria affecting the GI tract - GI system Flashcards
The GI tract
- mouth
- oesophagus
- stomach
- small intestine
- large intestine
gastroenteritis
- syndrome characterised by GI symptoms including nauseas, vomiting, diarrhoea and abdominal pain
diarrhoea symptoms /associations
- abnormal faecal discharged characterised by frequent and/or fluid stool
- associated with increased fluid and electrolyte loss
- often disease of small intestine
dysentery and common symptoms /associations
- abnormal inflammation of GI tract
- often blood and pus in faeces and pain, fever, abdomical cramps
- often disease of large intestine
enterocolitis
- inflammation of musoca of small and large intestine
bacteria that can cause/lead food poisoning
staph aureus
clostridium botulin
bacillus cerus
staph aureus and food poisoning
growth in food after human contamination
produce heat stable enterotoxins (resistant to stomach acid and digest enzymes)
sever vomiting
toxin gives reaction not bacteria itself
botulism
clostridium botulism
heat stable toxin
leads to flaccid paralysis and death
bacillis cerenus
found in food can grow in chains leads to an acute reaction gram + spore former bacillus forms an enterotoxin
can lead to vomiting or diarrhoea
gastric ulcers and bacteria which is associated with
form in the mucosa of stomach
can rupture and cause bleeding/inflamamtion
helicobacter pylori
how can helicobacter pylori survive in the stomach
- produces urease
- protective clod during transit to gastric mucin layer (pH 7)
- ammonia basis of breath test
stomach barrier
gastric pH 1-2
treatment of gastric ulcers
proton pump inhibitor plus metronidazole/amoxicillin and clarithromycin
intestine infections can lead to and treatment
diarrhoeal treatment
fluid and electrolyte replacement essential
E coli
gram - motile rod
causes diarrhoea
genetic diversity of E coli due to
- plasmid, lysogenic phage and transposon encoded pathogenicity islands
detection of E coli
lactose fermentation
go pink when on agar plate (macconky, hektoen enteric agar)
PCR/antigen tests for serotypes
e coli pathogenic straisn
EPEC
ETEC
EHEC
EPEC
bunding forming pili in attatchemtn - forms attatchemtn to cells via pedestal
injects proxies into host to manipulate cytoksletn, disruption of cili = diarrhoea
ETEC
attach via adhesive pili
produced heat stable and laial enterotoxins
EHEC
produces vero toxin STx
damages direct cells
can cause haemorrhage colitis/diaorhea
shigella
shiga toxin producing
bacillary dysentry, bloody stoools
spread foetal orally
samonella
salmonella typhimurium
invades Macrophage? cells and surrounding epitheloum
diarrhoea and enterocolitis
lab detection E coli/samonella
Macconky
pink
E coli - lactose ferments
Samonella- non lactose fermenter
(green with black centered)
Tymphoid fever caused by and complicatins
S typhi infection initiating in intestine transported systemically via macrophages complicaitons - GI lesions and haemorrhage - toxaemia – endocarditis - meningitis
no 1 cause of food poisning
camplyobacter spp
gram - micro aerophilis
symptoms
ulceration in jejunm
diarrhoea
cholera and what does it do
gram - comma shaped bacterium
large numbers required
change in sodium potassium pumps
usually a balance
increased secretion of chloride ions
stops sodium influx into cells, large loss of water
virus causes of GI infections
rota virus
winter vomiting virus/noro virus
- mainly oral foetal
rota virus
wheel like particle
diarrhoea caused by tissue damage in small intestine
low infectious dose
winter vomitig virus
norovirus
chills headache fever vomiting
