Transcript Helicobacter pylori

Helicobacter pylori
Clinical Medicine.Medical
department.Shandong University.
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?
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.
Biological properties of H. pylori
Morphology and structure

G- bacteria
 S or spiral-shaped bacterium
 HP have typical morphology
 Almost all the bacteria have
the same size
length:2.5~4.0μm
width:0.5~1.0μm
Submicroscopic structure of H.pylori

There are 2~6 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
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.
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.
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
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).
The picture on the right
is a dog helicobacter from
a patient who kept two
red setters in his house
all his life
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!
Staff
Lei Wu
Wei Ma
Peng Hao
Hui Wang
Fudi Chen
Lipan Peng
Xiaolei Wang
Shuncui Gao
Guangbin Cui
Hongyan Zhao
Yongjun Zhao
Huaqing Wang