Campylobacter Infections Workup

Updated: Jun 16, 2017
  • Author: Mahmud H Javid, MBBS; Chief Editor: Michael Stuart Bronze, MD  more...
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Workup

Laboratory Studies

Clinical diagnosis of enteric Campylobacter infection is established by demonstrating the organism via direct examination of feces or by isolation of the organisms.

Campylobacter organisms multiply more slowly than other enteric bacteria; thus, unusual techniques are used for isolation from fecal specimens.

These include growth at 42°C, use of antibiotic-containing media, and micropore filtration to keep larger bacilli from contaminating the culture.

Specific types of selective media are blood-based, antibiotic-containing media such as Skirrow, Butzler, and Campy-BAP.

Micropore filtration is based on filters with pores small enough to prevent the passage of microbes but large enough to allow passage of organism-free fluid. Filters with a pore diameter of 25 nm to 0.45 µm are usually used in this procedure, which can also be used to remove microorganisms from water and air for microbiological testing.

Multiple media types can be used to cultivate C jejuni, although Mueller-Hinton broth and agar best support C jejuni growth. The optimum atmosphere for C jejuni growth is 85% N2, 10% CO2, and 5% O2. [9]

Campylobacter organisms are oxidase positive with C jejuni hydrolysing hippurate. [10]

Results of stool cultures usually do not remain positive beyond 2 weeks.

Darkfield or phase-contrast microscopy of fecal specimens can also be used to assess for characteristic darting motility within 2 hours of passage.

A Gram stain of stool samples for characteristic curved rods is specific, with a sensitivity of 50-75%.

Fecal leukocytes and erythrocytes are present in 75% of patients with Campylobacter enteritis and can be detected with direct light microscopic examination using methylene blue or Gram stain.

Peripheral blood leukocytosis may be present.

Dehydration may be clinically evident in patients who are moderately to severely ill.

If infection with C fetus or another atypical species is suspected, incubation at 37°C and use of media without cephalosporins are required.

Serodiagnosis of C jejuni infections can be improved by using highly specific recombinant antigens in an enzyme-linked immunoassay (ELISA) technique. [11]

Real-time polymerase chain reaction (PCR) can be used to quickly and accurately detect C jejuni directly in diarrheal stool. [12]

The newer methods such as molecular biology techniques (PCR) and immunoenzymatic methods [13] are more sensitive than traditional culture methods. [14]

Culture-independent tests, such as rapid tests for detection of antigens in stool specimens, are available. [15, 16, 17] However, their use as standalone tests has been questioned. [18]

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Procedures

Up to 80% of patients with Campylobacter infection demonstrate evidence of proctocolitis on sigmoidoscopy. However, findings may be identical to those observed in pseudomembranous colitis or inflammatory bowel disease. Sigmoidoscopic abnormalities range from focal mucosal edema and hyperemia with patchy petechiae to diffuse or aphthoid ulceration.

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