Campylobacter is a genus of microaerophilic Gram-negative bacteria.
It is frequently found in raw meat, particularly chicken, and thus is a significant cause of
food poisoning due to handling raw meat or undercooking it.
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.
History The symptoms of Campylobacter infections were
described in 1886 in infants by Theodor Escherich.
These infections were named cholera infantum, or summer complaint.
The genus was first discovered in 1963; however, the organism was not isolated until 1972.
Infections [in the United States] from campylobacter—which is linked to many foods, including poultry,
raw milk and produce – has risen up to 14 percent in 2012 compared to 2006-2008.
They were at their highest level since 2000.
Genome and proteome The genomes of several Campylobacter species
have been sequenced.
The first Campylobacter genome to be sequenced was C. jejuni, in 2000.
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.
Sequence features.
Comparative genomic analysis has led to the identification of 15 proteins which are uniquely
found in members of the genus Campylobacter and serve as molecular markers for the genus.
Eighteen other proteins were also found which were present in all species except Campylobacter
fetus, which is the deepest branching Campylobacter species.
A conserved insertion has also been identified which is present in all Campylobacter species
except C. fetus.
Additionally, 28 proteins have been identified present only in Campylobacter jejuni and Campylobacter
coli, indicating a close relationship between these two species.
Five other proteins have also been identified which are only found in C. jejuni and serve
as molecular markers for the species.
Bacteriophage The confusing taxonomy of Campylobacter over
the past decades make it difficult to identify the earliest reports of Campylobacter bacteriophages.
Bacteriophages specific to the species we now know as C. coli and C. fetus, were isolated
from cattle and pigs during the 1960s.
Pathogenesis
Campylobacteriosis is an infection by Campylobacter.
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.
The infection is usually self-limiting and 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 . 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 that hinders the cells from dividing and activating
the immune system.
This helps the bacteria to evade the immune system and survive for a limited time in the
cells.
A cholera-like enterotoxin was once thought to be also 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.
Treatment Diagnosis of the illness is made by testing
a specimen of faeces.
Standard treatment is now azithromycin.
Quinolone antibiotics such as ciprofloxacin or levofloxacin are no longer as effective
due to resistance.
Dehydrated children may require intravenous 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.
Intestinal perforation is very rare; increased abdominal pain and collapse require immediate
medical attention.
Known risks 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.
In June 2014, the UK's Food Standards Agency started a campaign against washing raw chicken,
as washing can spread germs by splashing.
See also Periodontitis
References
External links Campylobacter genomes and related information
at PATRIC, a Bioinformatics Resource Center funded by NIAID
Sanitizing for Campylobacter in automated poultry processing environments for food safety
professionals Campylobacter info from the CDC