Lecture 7 - Campy And Helicobacter Flashcards
Describe key feature of campy group
- gram negative
- Motile
- spirilla
- microaerophilic (need approx 5% of oxygen) - small amounts
- oxidase positive
- catalase positive
- urease negative
- polar flagella
- Aw >0.98 high water activity needmoist environment
- unusual optimum for growth temp (hence called thermophile due to 42deg) optimum 37 (human) & 42 deg (chicken and probs other poultry)
What type of flagella does it have
Amphitricious - flagella either end
Slight spiral curved rod
What was campy first described as
Vibrio - bent rod (common shape - vibrio cholera)
Thought to be vetinary disease until what year and why
1946 - breakout in prison in Illinois jail - eat same food track disease - unpasteurised milk found campy
ZOONOSIS transmission proved
What is a type strain
Organism that represents all general features you’d expect an organism to have.
Campy fetus
Name 5 KEY species in campy enteropathogenic group
Jejuni - poultry
Coli - associated pork
Lari - seagulls and other birds - faeces in wind.
Upsaliensis and helveticus in pets particularly kittens and puppies (diarhoel disease) - interact with pet
What are the microaerophilic conditions to grow campy
5% O2
10% CO2
85% N2
What temp will campy not grow below
25 deg
What is a fastidious organism
Need a lot of love to grow
What bacteria is only one to be able to hydrolyse hippurate and what happens
C. Jejuni
Glycine formed (and benzoic acid) and glycine react with Ninhydrin and blue colour occur
What does VNC stand for
Viable but non culturable
What other organisms can VNC occur
Ecoli, pseudo, vib
What morphology does campy form when oxygen levels rise
Form coccoid
What stains were used to prove VNC
Cyto 9 - GREEN. go in live cells but some cant be cultured.
Propidium iodide - RED. in dead cells. In live cells membrane potential keep it out of cell but when dead lose this and overtake green
Unlike vib and pseudo cannot get campy back from coccoid VNC
Where does campy affect
GI pathogen
Describe pathogenesis of camp
Lots of pus
Mucus lining overlay gut endothelial cells
Use spiral morphology to corkscrew through (NOT FLAGELLA)
Anchor flagella band rotate spiral body through mucus lining of gut
CDT toxin increase tight junction between cells allow to get through easier
CAMPY CAN GO INTO CELL.
Once campy in cell directly interact with nucleus bring about interleukins which stimulate neutrophil, DC and macs - early immune response
What does CDT stand for
Cytolethal distending toxin
Increase tight junctions between cells. Get through easier
In what animal does campy live asymptomatically
Poultry - good carrier
Held in mucus lining
Is campy more sporadic or outbreaks
Sporadic
Low secondary transmission
Not in form to pass on to someone else in faeces
What percentage of chick tested positive and how many pieces does this equate to
76%
Every 8 pieces of chicken we touch is infected
What is tested for campy with chickens
Neck skins
Packaging
Skin/meat
What is a campy infection called and what does it cause
Campylobacteriosis and cause acute enteritis
Describe the campylobacteriosis infection
Last 2-7 days
Onset after 2-5 days feel unwell
Affect children & young adults
What is infectious dose of campy
500- 10^9
What is predicted cases of campy per year and how many die
280,000 and 110 deaths
Why does demyolinaion occur in Guillain Barré syndrome and how frequently does this disease arise due to campy
1 in 1000-3000
Antibodies raised agains LPS cross react with myelin sheath on neurones - demyelination. Body cannot move impulse so lead to temporary paralysis
What agar is used and why
Blood agar or CCDA (charcoal based medium ) to bind up O2
Selective supplements - suppress other organisms (may use faecal sample -have lots of bacteria)
What are the antibiotics used in agar
Vancomycin
Polymixin B
Trimethoprim
What temp is it incubated at
42 deg
What is used to get co2 environment
Gas jars and gas generation pouches - rip open pouch and put lid on.
Why is campy called self limiting infection hence supportive treatment
Once been ill tend to get better
What treatments are available for campy
Rehydration
Ciprofloxacin but not that effective
Becoming massively resistant to antibiotics due to poultry industry using them
For helicobacter who conducted stomach ulcer biopsy to discover helicobacter (spiral bacillus in 60%) of ulcer biopsy patients
Warren and marshall 1982
Why did warren and Mitchell achieve a nobel prize in 2005
Drank culture of helicobacter pylori, isolate organism, prove it is there, take antibiotics and show it disappeared
What two tissue trophisms does helicobacter have
1- Liver e.g. H.hepaticus
2- Gut - H. Pylori
Can lead to hepatic and gastric cancer respectively (not organisms stated)
What differs helicobacter to campylobacter
Helicobacter is UREASE POSITIVE
Metabolise urea to get ammonia to neutralise low pH of stomach
Helicobacter has 7 flagella out one side. What type of flagella is this
Lophotricious
Describe overview of pathogenicity of helicobacter
Gastric fluid low pH protected from epithelial cells by mucus layer
Helicobacter bind epithelial cells use urease to create light area (use as protective bubble)
Means pepsin CAN get to stomach and burn cells - like continuous heartburn
Continuous lead to cancer - constant replication can lead to errors
Helicobacter 3 toxin (cagA, HP-NAP, VacA, ROI) pathogenicity process
1- flagella propel pylori to epithelial cells stick via adhesins
2- pylori inject cagA via type IV secretion in host cell and release other toxins such as H.pylori neutrophil activating protein (HP-NAP) and VacA
3- VacA form large vacuoles and alter tight junctions
4- HP-NAP cross epithelial lining and recruit neutrophils and monocytes and cause damage by releasing reactive oxygen intermediates ROI’s
5- Cag A cause alteration of cytoskeleton, pedestal formation and signal to nucleus to release inflammatory lymphokines - amplify inflammation with recruitment of lymphocytes and further induce ROI release
6- this leads to acid permeation
What is type IV secretion analogous to
Bacterial conjugation method
What is helicobacter route of transmission
Oral-oral, faecal -oral
(Toothbrushes, if one person in family has genotype typical people in family also have it
What percentage of world is infected
50%
What agar is used for helicobacter (same antibiotic supplements) BUT RARELY USED
Brucella or Columbia
What methods used to be used to detect helicobacter
Isolation on agar
Biopsy - but invasive - false negative as stomach huge.
Urea Breath test - use C13 or C14 (carbon) to test for urease enzyme - detect radioactive co2 breathed out.
What method is used NOW to detect for helicobacter
Faecal antigen tests
95-98% sensitive
Take faecal sample and test. Non invasive
How to treat helicobacter
Treat with proton pump inhibitor (reduce acid production)
Take a while - can be up to months - some people stop.
1- metronidazole - Not nice to be on for long time
2- amoxicillin
3- tetracycline or Clarithromyocinin (10% failure due to resistance)
