Pathogenesis

18 species and subspecies exist, 11 of which are considered pathogenic to humans, causing enteric and extraintestinal illnesses. Two species are responsible for most cases of enteric campylobacteriosis: C. jejuni and C. coli. They both produce a similar illness.

Duration of shedding is 0-3 weeks; the average is 15 days. Untreated duration is 4 weeks. There is limited information on the period of infectiousness, but patients are probably not infectious if treated and diarrhoea has resolved.

Epidemiology

According to the Health Protection Agency the number of faecal isolates of Campylobacter spp. rose from just under 25,000 in England and Wales in 1986 to a peak of over 58,000 in 2000, falling to 49,880 in 2008.^[1] There was a significant increase in reported cases in 2009, particularly in the elderly. A number of factors could contribute to these increased numbers, eg an ageing population, increased travel, more eating out, changes in health-seeking behaviour; however, the causes of this increase currently remain unknown.

Incidence is highest in children, followed by young adults.^[2] There may be person-to-person transmission (faeco-oral route) with poor personal hygiene. Outbreaks occasionally occur in nurseries and institutions. 97% of sporadic disease can be attributed to animals farmed for meat and poultry.^[3]

Risk factors^[2]

• Undercooked meat, especially poultry.
• Pets with diarrhoea.
• Raw and inadequately pasteurised milk.
• Contaminated water supplies.
• Occupational exposure when processing poultry in abattoirs.
• Traveller's diarrhoea in Southeast Asia, especially Thailand.

Presentation

History

• The incubation period can be from 1 to 11 days but is usually 2 to 5 days.
• There is a prodromal illness of fever, headache and myalgia lasting up to 24 hours. The fever may be as high as 40°C and fever, whether high or low, may persist for a week.
• There are abdominal pains and cramps and profuse diarrhoea with up to 10 stools a day. The stool is watery and often bloody.
• There may be localised tenderness.
• Around a quarter of suffers have tenesmus.

Examination

• The patient often looks ill.
• Temperature may be high or low, but pyrexia is present in over 90%.
• The abdomen is diffusely tender, but tenderness may be more localised as right iliac fossa pain or left iliac fossa pain.

Investigations

• A sample of faeces is sent for culture to isolate the organism. A single negative sample does not exclude the disease. Cultures are rarely positive after 2 weeks.
• Microscopy of faeces may show erythrocytes and leukocytes.
• U&E and creatinine may show evidence of dehydration.
• Proctoscopy or sigmoidoscopy often shows proctocolitis, but it is difficult to distinguish from pseudomembranous colitis or ulcerative colitis.

Differential diagnosis

• Other infections:
  • Escherichia coli O157
  • Salmonella spp.
  • Shigella spp.
  • Amoebic dysentery
• Appendicitis.
• Inflammatory bowel disease.
• Pseudomembranous enterocolitis secondary to Clostridium difficile.
• Intussusception in infants.

Management

The basis of management is rehydration.

For work or school the exclusion period should be 48 hours from the last episode of diarrhoea.^[4]

Rehydration

This can usually be achieved by the oral route but, in more severe cases, intravenous fluids may be needed.

Anti-motility drugs

These should not be used routinely but may be considered for adults:

• Who need to return to work or attend a special event.
• Who have difficulty reaching the toilet quickly.
• Who are travelling (as empiric treatment, in conjunction with an antibiotic).

They should not be used in dysentery, or if the potential differential diagnoses include inflammatory bowel disease or pseudomembranous colitis, as toxic megacolon has been reported.^[5]

Antibiotics

The role of antibiotics is controversial.^[6][7] Some studies show that erythromycin rapidly eliminates the organism from the stool, but does not affect the duration of illness. Studies in children with dysentery due to C. jejuni have shown benefit from early treatment with erythromycin. Campylobacter spp. acquired from animals may show multiple resistance because of the use of antibiotics in animals.^[8] However, rising numbers of ciprofloxacin-resistant cases prompted withdrawal of quinolone use from commercial poultry farming in the USA.^[9]

Erythromycin and azithromycin are the most potent agents against Campylobacter spp.; erythromycin displays the highest susceptibility (91.1%).Tetracyclines and quinolones should be avoided in children.

Lactobacilli and probiotics may have a place in the prevention and treatment of campylobacteriosis and other forms of gastroenteritis. See separate related article Probiotics and Prebiotics.

Complications

• Acute bacterial gastroenteritis has been linked with the onset of irritable bowel syndrome (IBS) symptoms in approximately 15% of patients.^[10] These cases have been called postinfectious IBS. Campylobacter spp. is commonly associated with postinfectious IBS, as are E. coli O157, Salmonella spp. and Shigella spp.
• Unusual complications include haemolytic uraemic syndrome and thrombotic thrombocytopenic purpura.
• Other rare complications include Guillain Barré syndrome and reactive arthritis in the form of Reiter's syndrome.
• Toxic megacolon is a rare, but serious complication.

Prognosis

The disease is usually self-limiting. Occasionally, death may occur from dehydration in the elderly and vulnerable, especially if immunocompromised. C. jejuni can produce a serious bacteraemic condition in AIDS.

Prevention

• Milk should be pasteurised and drinking water chlorinated. It has been suggested that the provision of clean chlorinated water for chicken flocks might reduce the amount of contaminated meat reaching the market.
• Meat must be adequately cooked, and not pink in the middle. Uncooked meats should be kept separately from cooked and ready-to-eat foods in order to avoid cross-contamination.
• Infected healthcare workers should not work. Antibiotics may reduce spread by curtailing the duration of excretion.
• Those who are ill should not prepare or handle food.
• Cutting boards for cooked and uncooked meats and knives and other utensils must be kept apart.
• Hands should be washed before handling different food items, before eating or drinking, after going to the toilet and also after contact with animals, particularly pets and their bedding.