CAMPYLOBACTER

Campylobacter (meaning 'twisted bacteria') is a genus of bacteria that are Gram-negative, spiral, and microaerophilic. 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.

GENOME

The genomes of several Campylobacter species have been sequenced, providing insights into their mechanisms of pathogenesis. 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.

MOLECULAR SIGNATURES

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.

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.

CAUSE

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 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 (bowel motion).
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 (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. Intestinal perforation is very rare; increased abdominal pain and collapse require immediate medical attention.

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.

For more information view the source:Wikipedia

<