Campylobacter: C. Jejuni and C. coli have emerged as common human pathogens, causing mainly enteritis and occasionally systemic diseases. Morphology: Small Gram negative bacilli, with comma or S shape. They are motile with single unsheathed polar flagellum, at one or both poles.

Culture characters: They are microaerophilic, best growth at 42⁰C in atmosphere containing 5% O₂ & 10% CO₂. They grow on a selective medium called Skirrow’s medium (containing lysed blood agar and vancomycin, polymyxin & trimethoprim). Method of transmission: Usually, fecal-oral. Domestic animals such as cattle, chicken and dogs serve as a source of infection. Food and water contaminated with animal feces are the major source of human infection

Pathogenesis: C. jejuni is an invasive and toxogenic organism. It produce two exotoxins; enterotoxin and cytotoxin. Clinical picture: Incubation period 3 days Symptoms are severeng abdominal pain, nausea and diarrhea. Leucocytes are almost present in the feces, and frank blood may be apparent Symptoms usually resolve within few days, but excretion of bacteria may continue for several weeks.

Complications Ascptic arthritis or peripheral polyneuropathy (Guillain Barre’ syndrome; antibodies cross react with the myelin in nerve sheaths lead to symmetrical weakness). Laboratory diagnosis: A stool specimen is cultured on Skirrow’s medium and incubated at 42⁰C in a microacrophilic atmosphere (5% O₂) containing 10% CO₂. The organism is defined by failure to grow at 25C, oxidase positive and catalase positive and sensitivity to antibiotics.

Serology can he useful in patients presenting with aseptic arthritis or Guillain-Barre’ syndrome after about of diarrhea, Complement fixation test and ELISA tests can detect recent infection with C. jejuni and C. coli. Treatment: Erythromycin, nalidixic acid and tetracyclines. Partially sensitive to ampicellin.