.The stomach secretes gastric juice every day. Gastric juice consists of digestive enzymes and concentrated hydrochloric acid, which can tear apart the toughest food and microorganism.It used to be thought that the stomach contained no bacteria and was actually sterile, but H. pylori changed that view.
Why and how does HP cause diseases?
Let’s talk about HP in this lecture?
Contents
General description of H.pylori
Biological characteristics of H.pylori
Defense mechanism of H.pylori
Pathogenesis
Detection and treatment
Epidemiology
General description of H. pylori
1.H. pylori is a newly discovered stomach infection which was first reported by Barry Marshall and Robin Warren of Perth, Western Australia, in 1983.
2. The bacterium lives in the stomach of about half the people in the world. Many are apparently well, and most have an inflammation of the stomach lining, a condition which is called "gastritis".
3. Gastritis is the underlying condition which causes ulcers and other digestive complaints, possibly including cancer of the stomach.
HP is enclosed by glucocalyx after the treatment of acid
Defense mechanism of H.pylori
1. Reaction of urea hydrolysis
Once H. pylori is ensconced in the mucus, it is able to fight the stomach acid that does reach it with an enzyme called urease.
Urease converts urea, of which there is an abundant supply in the stomach (from saliva and gastric juices), into bicarbonate and ammonia, which are strong bases. This creates a cloud of acid neutralizing chemicals around the H. pylori, protecting it from the acid in the stomach.
The reaction of urea hydrolysis is important for diagnosis of H.pylori by the breath test.
Escape means that the body's natural defenses cannot reach the bacterium in the mucus lining of the stomach.
The immune system will respond to an H. pylori infection by sending white cells, killer T cells, and other infection fighting agents which cannot easily get through stomach lining.
Infection fighting agents do not go away either and the immune response grows and grows. Polymorphnucleas die, and spill their destructive compounds (superoxide radicals) on stomach lining cells.
Pathogenesis
Cytotoxin associated proteins(Cag A) and Vac A is the main factor of the virulence
Flagellum and urease is necessary for its adhesion and inhabitation
Adhesin
Diseases Associated with Helicobacter pylori
Duodenal Ulcers
Gastric (Stomach) Ulcers
Non-ulcer dyspepsia
Weird Syndromes
Stomach Cancer
Treatment
Treatment of H. pylori is usually simple but patients need repeated endoscopies, biopsies, and several courses of treatment with antibiotic drugs.
Epidemiology
H.pylori affects about 20% of persons below the age of
40 years, and 50% of those above the age of 60 years.
H.pylori is uncommon in young children.
Low socio-economic status predicts H.pylori infection.
Immigration is responsible for isolated areas of high
revalence in some Western countries.
Infective ratio all over the world
Animal Helicobacters
As pups, dogs catch it from their mother and have gastritis. When they grow up the Helicobacter appears to be pretty harmless. However, dog and cat helicobacter have been found in humans.
Don't let dogs lick you or your children on the face and mouth (nor cats).
