Campylobacter

• Campylobacter


  Foodborne pathogen
• Campylobacter causes Campylobacteriosis
• Morbidity due to infectious disease is higher in Māori
• Lower incidences of Campylobacter in Māori adults (access to health care?)
• Despite Māori being more likely to live in farming regions, Māori children have lower notification rates
• Children must present to a health care provider and be tested
• 1. 9 Campylobacter outbreaks each year in New Zealand
• Campylobacter is the most common cause of foodborne illness in New Zealand
• In 2006, New Zealand had one of the highest reported rates of campylobacteriosis worldwide
• Campylobacter


  • Gram-negative bacilli, spiral / helical-shaped
  • Motile / Flagellum at one or both ends
  • 17 species / 6 subspecies (2018)
  • Survives at low temperature for several weeks
  • Optimal growth 37˚C – 42˚C
  • Possesses surface-exposed antigens
  • Microaerophilic
• Carboxypeptidase


  Exopeptidase that removes single amino acids from carboxy end of oligopeptides
• Peptidoglycan


  Composed of alternating N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) residues connected by β-(1,4)-glycosidic bonds and cross-linked with short polypeptide chains
• Pgp2 (LD-carboxypeptidase)


  Cleaves tetrapeptides into tripeptides
• Pgp1 (DL-carboxypeptidase)


  Cleaves tripeptides into dipeptides
• Δpgp1 or Δpgp2 (no helical shape) results in attenuated motility and non-pathogenic (deficiency in colonization)
• Campylobacter lifestyle


  • Normal flora of the intestines, "loves to hang out in faeces"
  • Animals (e.g. cattle, swine, bird) can be commensal or pathogenic
  • 10 organisms (very low!) enough to cause infection
  • Microbiota in the colon has >1011 bacterial cells / g faecal
  • 5-25% people suffer from relapse (disease comes back)
  • Pathogens (C. jejuni, C. coli, C. fetus) require 1,000,000 CFU (106) to cause infection

  
• Campylobacter growth


  • Does not metabolize sugar (relies on other bacteria during infection)
  • Does not grow on regular growth media in the lab, requires protein (amino acids) or tri-carbolic acids (e.g. citric acid)
  • Grows slow (up to 5 days)
  • Patients can secrete pathogen for 2 weeks to 3 months
• Serology


  Antibodies present in blood serum (or other body fluids) used for diagnostic identification of antibodies in response to proteins, infection (pathogens), or autoimmune disease
• Bacterial antigenic properties


  H (flagella), O (somatic) sugar / lipopolysaccharide (LPS) - Lipid + polysaccharide (Endotoxins)
• Campylobacter serotyping (Penner Method)

  • Classification based on detection of soluble Heat-Stable (HS) antigens, primarily the Capsule polysaccharide (CPS)
  • Passive haemagglutination - HS-antigens extracted by heating at 100 degrees, incubated with red blood cells and then antibody specific for Campylobacter
• Campylobacter jejuni does not express LPS, instead has Lipo-oligosaccharides (LOS) with core and lipid A
• There are 47 HS serotypes (CPS) for Campylobacter, but many remain un-typeable
• Other Campylobacter serotyping methods

  • Lior method (detection of heat-labile antigens, e.g. present in flagella)
  • Analysis of the lipo-oligosaccharide (LOS) biosynthesis genes
• Campylobacteriosis is a common foodborne illness caused by Campylobacter
• Campylobacter serotyping


  Penner Method
• Burnham PM, Hendrixson DR: 'Campylobacter jejuni: collective components promoting a successful enteric lifestyle'
• Classification of Campylobacter


  • Traditionally based on LPS
  • C. jejuni does not express LPS
  • Lipo-oligosaccharides (LOS)
  • Core and lipid A
  • Capsule polysaccharide (CPS)
  • 47 HS serotypes (CPS)
  • Still many un-typeable
• Lior method


  Detection of heat-labile antigens, e.g. present in flagella, uses different chemical reagents (whole cells)
• LOS biosynthesis gene analysis

  Determines LOS structure and cell envelope of C. jejuni
• Campylobacteriosis


  Common cause of human gastroenteritis, zoonotic disease
• Bacteria entering the body

  1. Ingestion of bacterial cells

  2. Colonization of gut intestine

  3. Proliferation
• Cytolethal distending toxin (CDT)


  CdtA, CdtC bind membrane receptor, CdtB (Nuclease) enters via endocytosis, causes DNA double strand break and cell-cycle arrest (cell death)
• Treatment of Campylobacteriosis


  Generally not required, electrolyte and rehydration, antibiotics in invasive cases
• Antibiotics and antibiotic resistance

  Erythromycin / Azithromycin, Levofloxacin / Ciprofloxacin, Quinolone and Macrolide Resistance
• Complications in Campylobacteriosis


  • Bacteraemia, Hepatitis, Pancreatitis, Miscarriage
• Guillain-Barré syndrome (GBS)


  Post-infection complication, autoimmune disease affecting motor and sensory nerves, 1 out of 500 cases, fatal in 2-3% of cases, 25 - 40% C. jejuni infection
• Antibodies attack bacteria in the body

  1. Gangliosides (vs Lipo-oligosaccharide)

  2. Present on cell surface / found in nervous system

  3. Share antigenic epitopes with bacterial antigens
• Reactive arthritis


  Post-infectious complication, sterile inflammatory arthritis, 'reaction' to bacterial antigen, autoimmune disease, develops 2 – 6 weeks post infection, chronic or relapsing
• HLA-B27


  Antigen located on antigen presenting cell, T-cells recognize it, leads to unfolded protein response and immune system attack on healthy cells