Campylobacter jejuni: Pathogenesis & Identification

• Gram-negative bacteria
• Oxidase-positive
• Motile rods
• Microaerophilic
• Possess complex growth requirements

Campylobacter jejuni

• Features a seagull shape with a single flagellum.
• Campylobacter jejuni is isolated from stool specimens using a selective medium Campy plate
• A leading cause of food poisoning in Europe and the United States.
• Transmitted through ingestion of contaminated food, especially poultry, milk, or water.

Pathogenesis of Campylobacter jejuni

• Following ingestion, C. jejuni invades and damages the mucosal surface of the jejunum, ileum, and colon.
• Endotoxin, enterotoxins, and cytotoxins are produced, however, their precise roles in pathogenesis are not yet fully understood.
• Gastric juices inactivates organisms and are sensitive to complement-mediated killing.
• Organisms invade host cells, penetrating beyond the epithelial cell layer.
• Mesenteric lymph nodes become enlarged, fleshy, and inflamed in developed infections.
• Diarrhea results from intestinal mucosa disruption due to cell invasion and toxin production.

Symptoms of Campylobacter Infection

• Common symptoms include profuse watery bloody diarrhea, malaise, fever, abdominal pain, and cramps.
• Usually self-limiting, but can persist for at least a week.

Epidemiology of Campylobacter jejuni

• Incidence of C. jejuni enteritis peaks in young adults.
• Lack of gastric acid and hypogammaglobulinemia elevate the risk and severity of C. jejuni infection.

Clinical Findings and Diagnosis

• The average incubation period is 3 days, ranging from 1 to 7 days.
• Main symptoms: abdominal pain and diarrhea.
• Nausea is common, but vomiting is less frequent.
• Severe watery diarrhea occurs.
• Leukocytes are almost always present in the feces.
• Symptoms typically resolve within a few days.
• Campylobacter enteritis cannot be clinically distinguished from Salmonella or Shigella infection, however, abdominal pain tends to be more severe.
• In less developed regions, infection often presents as milder diarrhea, while asymptomatic colonization is common.

Laboratory Diagnosis

• Faecal specimens should be refrigerated pending delivery to the laboratory.
• Transport medium should also be used for rectal swabs.

Direct Detection in Feces

• A direct smear or wet preparation of liquid feces can reveal curved rods characteristic of campylobacters.

Microscopy

• Motility and morphology of Campylobacters are sufficiently characteristic.
• While occasionally useful, it is not routinely performed.

Culture

• Isolation of campylobacters from faces requires some form of selective culture to inhibit competing faecal flora.

Treatment

• Rehydration.
• Erythromycin.
• Quinolones.

Prevention and control

• Notes are not provided in the text.