GI infections Flashcards
Is the commensal flora of the gut mostly obligate anerobes or fac. anaerobic bacteria
Yes, bacteriodes 100: 1 e,coli
Common gut bacteria flora
Bacteriodes sp.
C. perfringens
E. coli
E. faecalis
Bacterial gastroenteritis is caused by what two things
Enterotoxin production and Adherence
Is cholera toxin mediated
Yes
Treatment options for vibrio chloreae
Oral vaccine, oral rehydration solution
What three nigerian gov states reported in the nigeria epidemic of 2018
Borno, Adamawa, Yobe
MOA of cholera toxin
Binding to GM1 gangliosides on intestinal cells, activating adenylate cyclase, and increasing cAMP levels, leading to excessive fluid and electrolyte secretion into the gut lumen
What type of toxin is cholera
AB5
Salmonella sp. causing GI infections
S. typhi
S. paratyphi
S. enterica: S. enteritidis, S.typhirium
What often causes salmonella
Contaminated foodstuffs, poultry
Salmonella spp. enter intestinal epithelial cells by what process
Bacterial-mediated endocytosis
Salmonella sp. disrupt what between cells
Tight cell junctions
What immune cell do Salmonella cells enter
Macrophages
What secretion system does Salmonella use to enter the cell
T3SS
Typhoid mary (Mary mallon)
A cook in the 19th century who spread salmonella
EHEC (E.coli)
Enterohaemorrhagic. Colitis/HUS
ETEC
Enterotocigenic E. coli, Traveller’s diarrhoea
EAggEC
Enteroggregative e.coli, traveller’s diarrhoea
EIEC
Enteroinvasine E. coli, dysentry like
EPEC
Enteropathogenic e.coli. childhood diarrhoea
E.coli O157 is what type of E. coli
VTEC, Shiga-toxin producing
HUS
Haemlytic uraemic syndrome
Source of E.coli O157, some patients develope what syndrome _ _ _
Cattle, UHS
C. difficle toxins are what type
AB, binary
C. difficle toxins cause what symptoms
- Diarrhoea
- Toxic megacolon
- Pseudomembranous colitis
C.diff: overveiw of intracellular modifications by TcdA and TcdB
- Glycosyltransferases
- Modify small GTPases
- Actin condensation
- Transcriptional activation
- Apoptosis
- Neutophil infiltration
- Chemokine production
- Disruption of tight junctions
- Apoptosis
- FLUID ACCUMULATION
Campylobacter species
C. jejuni and C. coli
Post-infectious complications of Campylobacter infection
reactive arthritis, Guillain–Barré syndrome,
irritable bowel syndrome
Campylobacter causes (not species names)
- raw or undercooked meat (poultry)
- unpasteurised milk
- untreated water
MOA of campylobacter
Motility, 1/2 flagella
Low infectious dose
Penetration into intestinal mucosa: adhesion, internalisation, translocation
Cytolethal distending toxin, arrest cell division in G2
C. jejuni method of infection
Apical attatchment, apical invasion, paracellular invasion, transcellular migration via actin. Basolateral invasion, intracellular survival in lysosome
Gastroenteritis treatment
Supportive
Avoid antibiotics, increase duration of salmonella carriage, worsen E.coli HUS
Except for extreme ages, campy, invasion
