Campylobacter Flashcards
what are the characteristics of Campylobacter?
- gram-negative, curved S-shaped rod
- motile with a single polar flagellum at one or both ends
- microaerophilic (ensures its survival in reduced-oxygen environments)
true or false: campylobacter is a zoonotic pathogen
true; can be infected via direct handling of animals, slaughter houses, contaminated feces, contamination of water, raw milk, and under cooked meet
what type of waters are sources of campylobacter species
tap, bore, and pond waters
what can ingestion of a sufficient-dose of organisms via the oral-gastric route, lead to?
one or more gastrointestinal and/or extragastrointestinal illnesses
when do campylobacter species peak?
in the summer time
what is the significance of Abattoir workers?
abattoir workers have developed antibody responses to campylobacter during their employment.
long-term workers shed C. jejuni but are asymptomatic, this is unlike new workers who commonly develop clinical signs of C. jejuni gastroenteritis during their first weeks
what are the clinical manifestations of campylobacter?
- brain abscess meningitis
- miller-fisher syndrome
- Guillain-Barre syndrome
- Bacteremia, Septicemia, Endocarditis, Myocarditis
- hepatitis
- IBS?
what is the most common clinical manifestation of campylobacter?
gastroenteritis
what species of campylobacter cause majority of gastroenteritis?
C. jejuni (responsible for 90% of cases with gastroenteritis)
what is the incubation period before symptoms of gastroenteritis show up?
24-72 hours, then acute diarrhea occurs and may be accompanied by fever, chills, headache, and abdominal cramping
what are rare clinical manifestation?
brain abscesses, periodontitis
significance of Guillain-Barre syndrome and Miller Fisher syndrome
- it is the most extensively studied extraintestinal manifestation associated with Campylobacter infection
Symptoms of Guillain-Barre and Miller Fisher syndrome:
generally begin with motor and sensory deficits in the lower extremities and spread to the upper extremities - can lead to the need for ventilator support
what is the main difference between Miller Fisher and Guillain-Barre syndrome?
patients with MFS: first nerve groups to be affected by paralysis are those in the head, resulting in difficulty controlling eye muscles and balance
patients with GBS: paralysis typically begins in the legs
Inflammatory Bowel Diseases (IBD):
- chronic inflammatory conditions of the GI tract including Crohn’s disease and ulcerative colitis
- patients with these diseases have lesions that occur at different sites along the GI tract
- evidence that Campylobacter infection may play a role
Esophageal Diseases:
- include gastroesophageal reflux disease (GERD), Barrett’s esophagus (BE), and esophageal adenocarcinoma
- bacterial composition of the esophagus differ between healthy individuals and those with GERD or BE
- possible mechanism could be that there is a strong esophageal immune response and inflammation in people whose esophagus is colonized with C. conisus could be causing symptoms
Bacteremia/Septicemia:
- most cases occur in those who are immunocompromised
- of these patients, 10-15% will die within 30 days of diagnosis
- generally associated with C. jejuni, C. coli, and C. fetus
describe the epidemiology of Campy
- population-level immunity influences the prevalence
- Campy is endemic in developing countries, where infection is usually limited to children which could lead to life long protective immunity
- adults in developing countries have asymptomatic campy but shed the bacteria
- in the developed world, the most common reported source of Campy infection is poultry products and water
- in canada infection rates vary by region
what are the main steps of campy molecular pathogenesis?
- motility
- adhesion
- protein secretion and invasion
- actin polymerization and endocytosis
- toxin production
what are the virulence factors of campy?
- CiaB: an exported virulence factor
- Type IV secretion apparatus: encoded on a large plasmid known as pVir
- flagellar export apparatus: may also be used to export virulence factors
what toxin does Campy release?
produces a tripartite complex toxin called cytolethal distending toxin (CDT)
what genes encode for the tripartite complex CDT toxin?
cdtA, cdtB and cdtC
what does cdtA, B and C do?
- CdtA and CdtC binds to the cell membrane and facilitates entry of CdtB
- CdtB is translocated into the cytoplasm and is transported via the Golgi apparatus to the ER and from there reaches the nucleus
- CdtB causes DNA damage and arrest the mitosis cell cycle of the cell
- leads to cell death, which increases permeability of the epithelium and results in diarrhea
summary of Campy:
- campylobacter is a very common foodborne bacterial pathogen in the developing and the developed world
- post-acute sequelae may occur such as GBS or possible IBD after initial infections is cleared
- good kitchen and hand hygiene are key to stopping infection
