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Helicobacter Pylori
Helicobacter (genus) pylori (species), commonly known as H. pylori, is a bacterium that causes gastritis of the inner lining of the stomach in humans and is the most common cause of ulcers worldwide (Delaney, Moayyedi and Forman 536). Ingestion of contaminated food and water and person-to-person contact is the most likely means of acquiring H. pylori. Portals for entry are largely oral, as oral-oral and oral-fecal contact are the most common contamination methods. About 30% of the adult population in the United States are infected and is more common in crowded living conditions with poor sanitation (Malcolm et al. 137). Infected individuals typically carry the infection indefinitely unless they are treated with medications to eradicate the bacterium. Other than the human stomach, there appears to be no natural reservoir for this bacterium. One out of every six patients with H. pylori infection will develop ulcers of the duodenum or stomach. The bacterium contains virulence factors such as urease, the vacuolating toxin, the cytotoxin-associated antigen CagA, or blood-group-antigen-binding adhesin, and likely account for the development of conditions other than gastritis and ulcers. H. pylori is associated with stomach cancer and a rare type of lymphocytic tumor of the stomach called MALT lymphoma (Sugiyama and Asaka 150).
History of H. Pylori
The bacterium was first described by Robin Warren and Barry Marshall, who isolated and cultured organisms from human mucosal specimens (Delaney, Moayyedi and Forman 536). Warren and Marshall contended that most stomach ulcers and gastritis were caused by colonization with this bacterium, not by stress or spicy food as the medical community had long assumed. The medical community was slow to recognize the role of this bacterium in stomach ulcers and gastritis, believing that no bacterium could survive for long in the acidic environment of the stomach. In 1994, the National...
pylori, and recommended that antibiotics be included in the treatment regimen. Many stomach ulcers are treated with antibiotics effective against H. pylori in practice today.
Structure
H. pylori is a spiral-shaped gram-negative bacteria ~3 micrometers long with a diameter of ~0.5 micrometers. It has 4-6 flagella and is microaerophilic, i.e. It requires oxygen at lower levels than those contained in the atmosphere. With its flagella and its spiral shape, the bacterium drills through the mucus layer of the stomach and attaches to epithelial cells. It contains the enzyme urease, which converts urea into ammonia and bicarbonate. The ammonia is useful to the bacterium since it partially neutralizes the very acidic environment of the stomach.
Sufficient colony growth can be seen in 3 days when the organism is plated onto Brucella-sheep blood agar and placed in a microaerophilic environment. A gram-stain will reveal weakly stained rod with a unique curvature. H. pylori is also strongly urease-positive, which may help in identification. Other laboratory indications include positive for urease and caalase, as well as motile and microaerophile (Hofman et al. 17).
Mode of Transmission
H. pylori is transmitted from person to person. While the exact mode of transmission is not entirely understood, evidence suggests that contact with infected vomit or stool will increase the risk of developing an infection due to H. pylori. The use of contaminated gastric tubes and the act of belching have been implicated in transferring H. pylori from the gastric cavity to the oral cavity and consequently to a new victim through oral contact. The direct consumption of H. pylori contaminated water, food, gastric contents or fecal matter will significantly increase the risk of developing infection (Perez-Perez, Rothenbacher…
Works Cited
Delaney, B., P. Moayyedi, and D. Forman. "Helicobacter Pylori Infection." Clin Evid.10 (2003): 535-48.
Hofman, P., et al. "Pathogenesis of Helicobacter Pylori Infection." Helicobacter 9 Suppl 1 (2004): 15-22.
Malcolm, C.A., et al. "Helicobacter Pylori in Children Is Strongly Associated with Poverty." Scott Med J. 49.4 (2004): 136-8.
McLoughlin, R., et al. "Therapy of Helicobacter Pylori." Helicobacter 9 Suppl 1 (2004): 42-8.
This is hardly used for detection of H. pylori alone but for ruling out the existence of other stomach maladies. It is quite expensive and requires a highly skilled physician. Stool Antigen Test; this is when the stool is analyzed for detection of any foreign antigens or proteins that are associated with H. pylori infection. The stool is known to be very sensitive and can also be use to assess
Helicobacter pylori is a gram-negative germ (bacterium) that typically infects the stomach or duodenum, but can also be found in other parts of the body. This bacterium is very common and it is believed that approximately half of the planet's population has it. Individuals in developing countries are predisposed to it as a consequence of poor sanitary conditions in these areas. The bacteria can typically be found in the inner
The use of aspirin and other NSAIDs has not been eliminated by studies as possible causes of PUD. H. pylori infection generally occurred less among patients with complicated ulcer disease than in those with uncomplicated ulcer disease. Many studies point to aspirin or NSAIDs as the other identifiable risk or cause of PUD. PPI has been shown to reduce dyspeptic symptoms, which develop from NSAID use. In the past,
Marshall and Warren discovered that the organism was there in almost every patient with gastric ulcer and inflammation. Based on the results of their findings, they suggested that Helicobacter pylori are involved in the aetiology of these diseases. In fact, Helicobacter pylori cause over 90% of duodenal ulcers and about 80% of gastric ulcers. After this discovery, research has been deep. This bacterium can be diagnosed by identification of the
Peptic ulcer, often known as a peptic ulcer disease, is a painful condition of the abdomen resulting in mucosal erosion of the gastrointestinal tract usually by excessive acid (consult, 2007) these erosions can only be categorized as peptic ulcers if they are larger than 0.5cm in diameter. Peptic ulcers can be classified according to the location where they appear hence the ulcers occurring in the duodenum are known as duodenal
It is related in this work: "Humans and their collective microbiota are segmented into many local communities, each comprising an individual human with his or her symbionts. This ecological pattern, characterized by strong interactions within distinct local communities and limited interactions or migration between them, is described as a metacommunity." (Dethlefsen, McFall-Ngai and Relman, 2007) a second level of metacommunity organization is in existence because "individual humans belong to