Campylobacter Jejuni: A Brief Overview on Pathogenicity-Associated Factors and Disease-Mediating Mechanisms
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Added on 2019-11-26
Campylobacter Jejuni: A Brief Overview on Pathogenicity-Associated Factors and Disease-Mediating Mechanisms
Added on 2019-11-26
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Immunity and DiseaseName University
Immunity and Disease2Campylobacter jejuni is a zoonotic pathogenic bacterium that is a causative organism for gastroenteritis in humans which is called campylobacteriosis. Infections caused by Campylobacter are more common than those caused by other pathogens, such as Salmonella,Shigella or Escherichia coli O157:H7. Consumption of undercooked poultry and handling of uncooked chicken causes most of the infections. Although the organism does not cause infection in chicken, it inhabits the intestine [ CITATION Wig13 \l 16393 ]. Contaminated drinking water and raw milk from infected cattle could also cause infection[ CITATION Hum87 \l 16393 ]. Chopping of vegetables on surfaces contaminated by poultry can increase the risk of food borne infection if the vegetables are served raw or partially cooked. Symptoms of an infection include fever, abdominal cramps and diarrhoea and diagnosis is usually done by culturing stool samples of patients. Presence of mucus and blood in the stoolsis common. Antibiotic resistant Campylobacter strains are difficult to treat[ CITATION Ach01 \l 16393 ]. The infection by Campylobacter jejuni causes inflammation of the intestinal surfaces and this leads to malabsorption of nutrients. C. jejuni is also known to cause autoimmune disorders Guillain-Barre syndrome and the Miller-Fisher syndrome. Other than gastroenteritis, the organism is associated with inflammatory bowel syndrome, colon cancer and Barrett's oesophagus. Other than the gastrointestinal system, it can cause infections in the lung, the pathogen has been known to cause brain abscess, bacteremia, meningitis and arthritis [ CITATION Kaa15 \l 16393 ]. The infection is known to occur more commonly in infants and children blow the age of five years and among young adults. A higher number of cases has been reported from North America, Australia and Europe. The problem of gastroenteritis is common in the developing countries.When infection by Campylobacter jejuni occurs, the immune system is able to recognize the pathogen as non-self and launches an immune response against the organism.
Immunity and Disease3The human innate has evolved in such a manner that it can recognize invading pathogens. It has to overcome the stealth mechanisms that the pathogen in capable of when it evades detection by the host's immune system The sentinel cells of the mucosal epithelium of the intestine are able to recognize bacteria by their pattern recognition receptors (PRRs). The bileacids that include the cholates and the deoxycholates have a detergent like action and can kill bacteria. In the human intestine the concentration of the bile acids ranges from 0.2%-2%[ CITATION Fon16 \l 16393 ].Another level of protection from infection is provided by the mucus gel layer that coats the intestinal epidermis. It is made up of the mucin proteins or the MUCs [ CITATION Hol04 \l 16393 ]. The MUCs play an important role in immune surveillance. The mucins associated with the membrane, example, MUC1 and the secreted mucins MUC2 re proteins with domains that are arrays of tandem repeats and re rich in the amino acids threonine, serine and proline, the PTS domains. These domains are glycosylated. It has been found that inappropriate expression of MUC1 can predispose human beings to inflammatory and infectious diseases [ CITATION She13 \l 16393 ]. MUC1 is overexpressed in case of C. jejuniinfection of the intestine. It promotes anti-inflammatory effect against the bacteria by reducing the activation of NF-κB and decrease in IL-8 cytokine production[ CITATION Fon16 \l 16393 ].When MUC1 expression is less the surface expression on antigen presenting cells (APCs) of CD40, CD80 and CD86 increases. This results in a higher secretion of TNF-α and a greater stimulation of CD4+ T cells results. Lack of MUC2 causes increase in the productionof pro-inflammatory cytokines occurs, these include, IL-1β, TNF-α and INF-γ. Local inflammation protects against C. jejuni infection [ CITATION Fon16 \l 16393 ].
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