Helicobacter pylori

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Helicobacter pylori

• Clinical Medicine.Medical department.Shandong
  University.

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Introduction

• .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?
• Lets talk about HP in this lecture?

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Contents

• General description of H.pylori
• Biological characteristics of H.pylori
• Defense mechanism of H.pylori
• Pathogenesis
• Detection and treatment
• Epidemiology

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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.

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Biological properties of H. pylori
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Morphology and structure

• G- bacteria
• S or spiral-shaped bacterium
• HP have typical morphology
• Almost all the bacteria have the same size
• length2.54.0µm
• width0.51.0µm

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Submicroscopic structure of H.pylori

• There are 26 flagella at one end of HP
• The flagella can exist at two ends during fission
• Flagella play important role in motion and
  adhesion
• HP is enclosed by glucocalyx after the treatment
  of acid

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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.

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Defense mechanism of H.pylori

• 2. Escape of natural defense
• 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.

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Pathogenesis

• Cytotoxin associated proteins(Cag A) and Vac A
  is the main factor of the virulence
• LPS also play great importance
• Flagellum and urease is necessary for its
  adhesion and inhabitation
• Adhesin

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Diseases Associated with Helicobacter pylori

• Duodenal Ulcers
• Gastric (Stomach) Ulcers
• Non-ulcer dyspepsia
• Weird Syndromes
• Stomach Cancer

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Treatment

• Treatment of H. pylori is usually simple but
  patients need repeated endoscopies, biopsies, and
  several courses of treatment with antibiotic
  drugs.

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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.

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Infective ratio all over the world
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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).
• The picture on the right
• is a dog helicobacter from
• a patient who kept two
• red setters in his house
• all his life

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Prospect of Helicobacter pylori

• The study of H.pylori has lasted for 20 years
  since it was found by Warren and Marshall in
  1983.
• During the past 20 years,all the passages
  published on HP have reached 14000,that means the
  study of HP is one of the most hot fields.
• Try our best to conquer it!

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StaffLei Wu Wei Ma Peng Hao Hui
WangFudi ChenLipan PengXiaolei Wang Shuncui
GaoGuangbin Cui Hongyan Zhao Yongjun Zhao
Huaqing Wang
Thank all my partners