15.8H: Campylobacter
- Discuss the method of transmission for Campylobacter
Description of Campylobacter Bacteria
Campylobacter is a genus of bacteria that are Gram-negative, spiral, and microaerophilic. The name means “twisted bacteria” because of the spiral formation; motile, with either unipolar or bipolar flagella, the organisms have a characteristic spiral/corkscrew appearance and are oxidase-positive.
Campylobacter jejuni is now recognized as one of the main causes of bacterial foodborne disease in many developed countries. At least a dozen species of Campylobacter have been implicated in human disease, with C. jejuni and C. coli the most common. C. fetus is a cause of spontaneous abortions in cattle and sheep, as well as an opportunistic pathogen in humans.
Campylobacter species contain two flagellin genes in tandem for motility: flaA and flaB. These genes undergo intergenic recombination, further contributing to their virulence. Nonmotile mutants do not colonize.
Methods of Transmission and Treatment
The common routes of transmission are fecal-oral; the bacteria are introducted through ingestion of contaminated food or water and by the eating of raw meat. Infection produces an inflammatory, sometimes bloody diarrhea, periodontitis, or dysentery syndrome, mostly including cramps, fever and pain. The infection is usually self-limiting. In most cases symptomatic treatment by liquid and electrolyte replacement is enough in human infections. The use of antibiotics, on the other hand, is controversial.
Diagnosis
Symptoms typically last for five to seven days. The sites of tissue injury include the jejunum, the ileum, and the colon. Most strains of C. jejuni produce a toxin (cytolethal distending toxin) that hinders the cells from dividing and activating the immune system. This symptom helps the bacteria evade the immune system and survive for a limited time in the cells. A cholera-like enterotoxin was also once thought to be made, but this appears not to be the case. The organism produces diffuse, bloody, edematous, and exudative enteritis. Although rarely has the infection been considered a cause of hemolytic uremic syndrome and thrombotic thrombocytopenic purpura, no unequivocal case reports exist. In some cases, a Campylobacter infection can be the underlying cause of Guillain-Barré syndrome. Gastrointestinal perforation is a rare complication of ileal infection.
Diagnosis of the illness is made by testing a specimen of faeces (bowel motion). Standard treatment is now azithromycin and, on occassion, terbinafine. Quinolone antibiotics such as ciprofloxacin or levofloxacin are no longer as effective due to resistance. Dehydrated children may require intravenous (by vein) fluid treatment in a hospital. The illness is contagious, and children must be kept at home until they have been clear of symptoms for at least two days. Good hygiene is important to avoid contracting the illness or spreading it to others.
Key Points
- Campylobacter jejuni is now recognized as one of the main causes of bacterial foodborne disease in many developed countries.
- The common routes of transmission are fecal-oral, ingestion of contaminated food or water, and the eating of raw meat.
- It produces an inflammatory, sometimes bloody, diarrhea, periodontitis or dysentery syndrome, mostly including cramps, fever and pain.
Key Terms
- microaerophilic : living and thriving in an environment low in oxygen
- enteritis : Inflammation of the intestines, generally the small intestine, that may lead to diarrhea.
- flagella : A flagellum is a lash-like appendage that protrudes from the cell body of certain prokaryotic and eukaryotic cells.