Campylobacter
bacteria are the number-one cause of food-related gastrointestinal illness in the
United States. This scanning electron microscope image shows the characteristic
spiral, or corkscrew, shape of C. jejuni cells and related structures.
Campylobacteriosis
is caused by Campylobacter bacteria (curved or spiral, motile,
non–spore-forming, Gram-negative rods). The disease is usually caused
by C.
jejuni, a spiral and comma shaped bacterium normally found in cattle,
swine, and birds, where it is nonpathogenic, but the illness can also be caused
by C. coli (also found in cattle, swine, and
birds), C. upsaliensis(found in cats and dogs)
and C. lari (present in seabirds in
particular).
One effect
of campylobacteriosis is tissue injury in the gut.
The sites of tissue injury include the jejunum, the ileum, and the colon.C
jejuni appears to achieve this by invading and destroying epithelial
cells.
C. jejuni can
also cause a latent autoimmune effect on the nerves of the legs, which is
usually seen several weeks after a surgical procedure of the abdomen. The
effect is known as an acute idiopathic demyelinating polyneuropathy (AIDP),
i.e. Guillain–Barré syndrome, in which one sees
symptoms of ascending paralysis, dysaesthesias usually below the waist, and, in
the later stages, respiratory failure.
Some strains
of C jejuni produce a cholera-like
enterotoxin, which is important in the watery diarrhea observed in infections.
The organism produces diffuse, bloody, edematous, and exudative enteritis. In a
small number of cases, the infection may be associated with hemolytic uremic syndrome and thrombotic thrombocytopenic purpura through
a poorly understood mechanism.
Transmission
The common routes of transmission for the
disease-causing bacteria are fecal-oral, person-to-person sexual contact,
ingestion of contaminated food (generally unpasteurized (raw) milk and
undercooked or poorly handled poultry), and
waterborne (i.e., through contaminated drinking
water). Contact with contaminated poultry, livestock, or household pets,
especially puppies, can also cause disease.
Animals
farmed for meat are the main source of campylobacteriosis. A study published in
PLoS Genetics (September 26, 2008) by researchers from Lancashire, England, and
Chicago, Illinois, found that 97 percent of campylobacteriosis cases sampled in
Lancashire were caused by bacteria typically found in chicken and livestock. In
57 percent of cases, the bacteria could be traced to chicken, and in 35 percent
to cattle. Wild animal and environmental sources were accountable for just
three percent of disease.
The
infectious dose is 1000–10,000 bacteria (although ten to five hundred bacteria
can be enough to infect humans). Campylobacter species are sensitive
to hydrochloric acid in the stomach, and
acid reduction treatment can reduce the amount of inoculum needed
to cause disease.
Exposure to
bacteria is often more common during travelling, and therefore
campylobacteriosis is a common form of travelers' diarrhea.
Epidemiology
Campylobacter is
one of the most common causes of human bacterial gastroenteritis. For
instance, an estimated 2 million cases of Campylobacter enteritis occur
annually in the U.S., accounting for 5–7% of cases of gastroenteritis.
Furthermore, in the United Kingdom during 2000, Campylobacter jejuni was involved in 77.3% in
all cases of laboratory confirmed foodborne
illness. About
15 of every 100,000 people are diagnosed with campylobacteriosis every year,
and with many cases going unreported, up to 0.5% of the general population may
unknowingly harbor Campylobacter in their gut.
A large
animal reservoir is present as well, with up to 100% of poultry, including chickens, turkeys, and
waterfowl, having asymptomatic infections in their intestinal tracts. Infected chicken feces
may contain up to 109 bacteria per 25 grams, and due to the
installations, the bacteria are rapidly spread to other chickens. This
vastly exceeds the infectious dose of 1000–10,000 bacteria for humans.
In January
2013, the UK's Food Standards Agency warned that
two-thirds of all raw chicken bought from UK shops was contaminated with
campylobacter, affecting an estimated half a million people annually and
killing approximately 100.
Symptoms
The prodromal symptoms are fever, headache, and myalgia, which
can be severe, lasting as long as 24 hours. After 1 - 5 days, typically, these
are followed by diarrhea (as many as 10 watery, frequently bloody,
bowel movements per day) or dysentery, cramps, abdominal
pain, and fever as
high as 40 °C (104 °F). In most people, the illness lasts for 2–10
days. It is classified as invasive/inflammatory diarrhea, also described as
bloody diarrhea or dysentery.
There are other
diseases showing similar symptoms. For instance, abdominal pain and tenderness
may be very localized, mimicking acute appendicitis.
Furthermore, Helicobacter pylori is closely related to Campylobacter and
causes peptic ulcer disease.
Other factors
In patients
with HIV,
infections may be more frequent, may cause prolonged bouts of dirty brown
diarrhea, and may be more commonly associated with bacteremia and
antibiotic resistance. In participants of unprotected anal intercourse,
campylobacteriosis is more localized to the distal end of the colon and
may be termed a proctocolitis. The severity and persistence of
infection in patients with AIDS and hypogammaglobulinemia indicates that both
cell-mediated and humoral immunity are important in preventing and terminating
infection.
Diagnosis
Campylobacter organisms
can be detected by performing a Gram stain of a stool sample with high specificity and a sensitivity of ~60%, but are most often
diagnosed by stool culture. Fecal leukocytes should
be present and indicate the diarrhea to be inflammatory in nature. Methods
currently being developed to detect the presence of campylobacter organisms
include antigen testing via an EIA or PCR.
Treatment
The
infection is usually self-limiting, and in most cases, symptomatic treatment
by liquid and electrolyte replacement is enough in human
infections.
Antibiotics
Antibiotic
treatment is controversial, and has only a marginal benefit (1.32 days) on the
duration of symptoms, and should not be used routinely.
Erythromycin can
be used in children, and tetracycline in
adults. Some studies show, however, that erythromycin rapidly
eliminates Campylobacter from the stool without affecting the
duration of illness. Nevertheless, children with dysentery due
to C.
jejuni benefit from early treatment with erythromycin. Treatment with
antibiotics, therefore, depends on the severity of symptoms. Quinolones are
effective if the organism is sensitive, but high rates of quinolone use in
livestock means that quinolones are now largely ineffective.
Antimotility
agents, such as loperamide, can lead to prolonged illness or intestinal
perforation in any invasive diarrhea, and should be avoided. Trimethoprim/sulfamethoxazole and ampicillin are
ineffective against Campylobacter.
In animals
In the past,
poultry infections were often treated by mass administration of enrofloxacin and sarafloxacin for
single instances of infection. The FDA banned this practice, as it promoted the
development of fluoroquinolone-resistant populations. A
major broad-spectrum fluoroquinolone used
in humans is ciprofloxacin.
Currently
growing resistance of the Campylobacter to fluoroquinolones and macrolides is
of a major concern.
Prognosis
Campylobacteriosis
is usually self-limited without any mortality (assuming proper hydration is
maintained). However, there are several possible complications.
Complications
Complications
include toxic megacolon, dehydration and sepsis. Such
complications generally occur in young children (< 1 year of age) and
immunocompromised people. A chronic course of the disease is possible; this
disease process is likely to develop without a distinct acute phase. Chronic
campylobacteriosis features a long period of sub-febrile temperature
and asthenia;
eye damage,arthritis, endocarditis may
develop if infection is untreated.
Occasional
deaths occur in young, previously healthy individuals because of blood volume
depletion (due to dehydration), and in persons who are elderly or
immunocompromised.
Some
individuals (1–2 in 100,000 cases) develop Guillain–Barré syndrome, in which the
nerves that join the spinal cord and brain to the rest of the body are damaged,
sometimes permanently. This occurs only with infection of C. jejuni and C.
upsaliensis.
Prevention
- Pasteurization of milk and chlorination of drinking water destroy the organism.
- Treatment with antibiotics can reduce fecal excretion.
- Infected health care workers should not provide direct patient care.
- Separate cutting boards should be used for foods of animal origin and other foods. After preparing raw food of animal origin, all cutting boards and countertops should be carefully cleaned with soap and hot water.
- Contact with pet saliva and feces should be avoided.
The World
Health Organization recommends the following:
- Food should be properly cooked and hot when served.
- Consume only pasteurized or boiled milk and milk products, never raw milk products.
- Make sure that ice is from safe water.
- If you are not sure of the safety of drinking water, boil it, or disinfect it with chemical disinfectant.
- Wash hands thoroughly and frequently with soap, especially after using the toilet and after contact with pets and farm animals.
- Wash fruits and vegetables thoroughly, especially if they are to be eaten raw. Peel fruits and vegetables whenever possible.
- Food handlers, professionals and at home, should observe hygienic rules during food preparation.
- Professional food handlers should immediately report to their employer any fever, diarrhea, vomiting or visible infected skin lesions.
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