Campylobacter Flashcards
Sources of infection of campylobacter
Direct contact
faecal contaminated environments
Campylobacter general facts
Gram negative
Spiral
Motile
Non-saccharolytic
Non-spore forming
Microaerophilic
Grows between 32-45 degrees
How many campylobacter per gram can a chicken carry in the GI tract
10 billion
Where is the greatest number of campylobacter normally found?
The caeca
C. jejuni in chickens
Does not cause intestinal disease following naturally acquired infection
Little or no pathology
Molecular and cellular features of the innate immune response to C. jejuni in chickens
Colonisation of teh chicken induces a proinflammatory response in mucosal tissue
May be a controlled inflammatory process during colonisation
What age of chickens are free of campylobacter
Newly hatched chicks
Most flocks become infected 2-3 weeks after the placement of chicks into a broiler house
Campylobacter in cats and dogs
Normal cats and dogs shed C. jejuni, C. coli, C. upsaliensis, and C. helveticus
Usually subclinical
Viral or parasitic enteritis is a predisposing factor
Prevalence higher in dogs than cats
Clinical signs of campylobacter in dogs and cats
Non-specific
Mild to watery diarrhoea
Lethargy, dehydration, anorexia
Normally self limiting with mild to moderate signs of acute enteritis
Zoonotic and public health implications of Campylobacter and squamates
either by cross-contamination through their faeces, pet handling or as a result of close interaction
higher pathogen carriage rate and shedding in captive lizards compared with free-living wild lizards
Campylobacter in cattle
C. jejuni, C. coli, C. hyointestinalis, C. fetus subsp. fetus, and C.r lari in healthy cattle
Feedlot cattle maintain a higher Campylobacter carriage rate than adult, pasture-fed animals
Milk can be infected directly, by Campylobacter infection of the udder, or faecal contamination
Campylobacters in colitis in weaned pigs
C. coli and C. jejuni as intestinal commensals
Around 50% of commercial pigs excrete Campylobacter
Usually asymptomatic
dehydration / diarrhoea with blood & mucous / loss of body condition
C. hyointestinalis may be associated with disease such as proliferative enteritis
Steps in C. jejuni gut invasion
- Adherence of the bacteria to the host cell
- Secretion of effector proteins into the host cell and activation of host-cell signalling pathways
- Host cell rearrangement of microfilaments, microtubules and actin resulting in a membrane ruffle
- Endocytosis, or invasion of Campylobacter into the cell
- Limited or no replication of the bacteria inside the host cell and movement of the vacuole to the basolateral surface
- Exocytosis at the basolateral surface
- Possible reinvasion at the basolateral surface
- CDT-induced cell death and release of IL-8 that stimulates recruitment of inflammatory cells, further contributing to tissue damage
- Uptake into monocytes and/or macrophages and dissemination via lymph or the blood to other sites of the body
Diagnosing and typing of Campylobacter spp.
A special transport medium is required
C. jejuni and C. coli remain viable in faeces at room temp for around 3 days, and at 4oC for around 1 week
In terms of growing Campylobacter in culture or on plates, this requires a Microaerophilic or anaerobic environment (dependent on species), a temperature of 42oC for Campylobacter jejuni, and 37oC for other enteric campylobacters
On freshly prepared media, Campylobacter produce grey, flat, irregular and spreading colonies. As the moisture content decreases the colonies become round, convex, and glistening, with little spreading
Traditionally, phenotypic methods have been used to diagnose Campylobacter, for example, serotyping and phage typing. These are Relatively easy to perform, however, they do not allow strains to be typed and they detect characteristics expressed on the cell surface.
Now, genotypic methods are used. These methods include multi locus sequence typing (or MLST) and Whole Genome Sequencing (or WGS). These techniques discriminate between strains better and can be applied to epidemiological studies.
How many cases of Campylobacter food poisoning per annum?
over 500 million globally
0.5 million in UK
