Food infections (Campylobacter jejuni)

Campylobacter infections are among the most common bacterial infections in humans. They produce both diarrheal and systemic illnesses. In industrialized regions, enteric Campylobacter infections produce an inflammatory, sometimes bloody, diarrhea or dysentery syndrome.

•         Campylobacter jejuni is the leading cause of gastroenteritis in the US and probably world-wide. 

•         Hawai'i has the highest incidence in the country à about 900 reported cases a year with an incidence of 75/100,000, but the thinking is that infections are grossly under reported.

History of Campylobacter jejuni          

Awareness of the public health implications of Campylobacter infections has evolved over more than a century. In 1886, Escherich observed organisms resembling Campylobacters in stool samples of children with diarrhea. In 1913, McFaydean and Stockman identified Campylobacters (called related Vibrio) in fetal tissues of aborted sheep. In 1957, King described the isolation of related Vibrio from blood samples of children with diarrhea, and in 1972, clinical microbiologists in Belgium first isolated Campylobacters from stool samples of patients with diarrhea. The development of selective growth media in the 1970s permitted more laboratories to test stool specimens for Campylobacter. Soon Campylobacter [species] were established as common human pathogens.

Properties of the organism

•         Curved s-shaped gram (-) rods, motile with a single polar flagellum at one or both ends.

•         Defined "viable but not culturable" state.

•         Respiratory metabolism, microaerophilic. 

•         Grow with 10% CO₂ / 5% O₂.  Some species / strains require additional H₂ in the atmosphere

•         C. jejuni will grow at 42^o C and this is used as a selection criterion.

•         The organism is unusually thin (0.2 - 0.9m).

•         Viable but non culturable

Reservoirs and epidemiology

Human cases are associated with:

•         Poultry - especially eating chicken out

•         Pets - especially young puppies

•         Water supply

•         Raw milk

•         Most cases occur in the summer months -- late spring to early autumn. 

Cell Structure and Metabolism

Campylobacter, a curved and motile rod, is often flagellated and causes bacterial infections in the body (FDA, 2003). Gene sets have been identified that produce sialic acid on the cell surface. This sialic acid enables Campylobacter to survive in the host's body by avoiding the body's immune response, sometimes even confusing the body into attacking itself (Sanger Institute).

Pathogenesis and Disease Characteristics

•         Low infectious dose

•         Two disease entities:

v  Diarrhea

v  Dysentery

•         Associated with Guillain-Barre syndrome.

Virulence factors

•         C.jejuni can invade intestinal epithelial cells.

•         C.jejuni secretes a number of novel proteins upon cultivation with enterocytes:

v   CiaB

•         pVir, present only in some strains of Cj appears to be important for invasion.

•         Microtubule mediated endocytosis occurs

•         Cj apparently stays within vacuole

•         Adenyl cyclase activating cholera toxin-like enterotoxin

•         Microtubule mediated endocytosis occurs and microfilament mechanism may be involved too

•         Microtubules aggregate into finger-like protrusions with C.jejuni at the tips.

•         Cytolethal Distending Toxin

v  Irreversible cell cycle arrest

v  All three CDT genes need to be expressed for activity

•         Adenyl cyclase activating enterotoxin?

Guillaine-Barrè Syndrome

•         Ascending muscle weakness or paralysis, rapidly progressing.

•         40% of GBS patients have evidence of Campylobacter infection.

•         LPS oligosaccharides structurally related to human motor neuron gangliosides.

Precautions to C.jejuni infections

·           Always cook meat, especially poultry, to safe minimum temperatures.

·         Keep raw meat, especially poultry, separate from other foods.

·         Do not drink raw or unpasteurized milk.

Campylobacter infection treatment

The use of antibiotics to treat Campylobacter infections is controversial, with studies showing that erythromycin rapidly eliminated Campylobacter organisms from the stool without affecting the duration of illness. Studies in children with C jejuni dysentery have shown benefit from early treatment with erythromycin. Antibiotics may be indicated if any of the following occur:

• High fever
• Bloody diarrhea
• Excessive bowel movements (ie, >8 stools per day)
• Worsening symptoms
• Failure of symptoms to improve
• Persistence of symptoms for longer than 1 week
• Pregnancy
• HIV infection and other immunocompromised states
• Avoid antimotility agents because they prolong the duration of symptoms and have been associated with fatalities.
• Individuals with hypogammaglobulinemia who have recurrent C jejunibacteremia may require fresh frozen plasma with antibiotics.
• Patients with severe dysentery or a relapsing course may require hospitalization.
• Patients with endovascular C fetus infections require at least 4 weeks of treatment; gentamicin is believed to be the agent of choice. Treatment with ampicillin or third-generation cephalosporins is an alternative.
• Treat C fetus CNS infections for 2-3 weeks with third-generation cephalosporins, ampicillin, or chloramphenicol.