Download H. pylori

THE GENUS HELICOBACTER
Gram –ve rod, curved
oxidase +
microaerophilic
strong urease
activity
At least 22 species included in this genus
Majority colonize mammalian stomach or
intestine
Human pathogens :
H. pylori, H. cinaedi, H. fennelliae
H. pylori :
* Mode of transmission is unclear
oral- oral, fecal-oral
houseflies, ingestion
* Cultured from feces and dental plaque
* 50% of adults older than age 60 are
infected
* Highest rates of initial infection occur
by age 10 especially between ages
4-5 year
Pathogenesis & Pathogenicity
 colonizes the mucous layer of the antrum
and fundus of stomach

does not invade the epithelium

ability to colonize the gastric mucosa
genome is the most variable sequence,
changing the expression of OMP

persist host immune defense

cause host tissue damage

Gastritis, peptic ulcer, gastric cancer
Duodenal peptic ulcer
Virulence factor :
surface is covered with urease enzyme
produce ammonia (base) from urea in the
host, help to protect from acid

adhesins for colonization of mucosal
surfaces

stimulate cell to initiate mediators of
inflammation

cytotoxin causes damage to gastric
epithelial cells

H. cinaedi and H. fennelliae
* cause proctitis, enteritis, sepsis in
homosexual men
* septicemia, cellulitis and meningitis
in immunocompromised patients
H. pylori in cats :
* has been cultured from feces, salivary
secretion, gastric fluid and dental plaque
of naturally-infected cats
* infected cats had moderate to severe
lymphofollicular gastritis
* clinical sign : vomiting, weight loss
possibly diarrhea (subclinical sign)
Feline isolates shown to be genetically
similar to human isolate
(99.7% identity in 16s rRNA)
Human to cats to human transmission of
H. pylori as a reverse zoonosis?
* Epidemiologic studies H. pylori infection
and animal contact are conflicing
* Overall rate of colonization of stray cats
much lower than that of humans
* Humans may the 1ry reservoir of the
organism
human
cat
Dogs and cats
H. felis
H. bizzozeronii
H. salomonis (naturally infected dog)

asymptomatic, some show intermittent
vomiting, weight loss and emaciation

possibility of zoonotic infection has been
considered
H. heilmannii
 associated highest infection rates in
dogs and cats (group confinement)
 0.2-0.4% human gastric cases species
resembling H. heilmannii isolated from cats
and dogs
H. bizzozeronii
swine, dog, and cat, human)
* found in gastric mucosa
* pig contact is an important risk for
humans
* infection of humans:
milder from of chronic gastritis than
H. pylori and may be self-limiting
Other Helicobacter :
H. mustelae
- hypergastrinemia in ferret
H. acinomyx - gastritis in cheetah
H. cinaedi
- part of flora of hamster
H. suis
- swine, gastric ulcer
There has been no report
pointing to a direct relationship
of human infection by animal
helicobacter spp. and gastric
disorder in human caused by H.
pylori
Direct Detection :
* Warthin-Starry stain, silver stain,
Giemsa biopsy specimens
* placing crush tissue biopsy in urea
broth
* Urea breath test
* H. pylori stool antigen tests
Isolation & Identification
* Demonstration of histologic evidence of
inflammatory changes accompanied
by spiral organism in mucosa
Biopsy speciman : Gastric mucosa
e.g. chocolate agar, brucella agar
+ 5% sheep blood
4-7 days of incubation
Biochemical test
typical cellular morphology
Positive results for :
Oxidase
Catalase
Rapid urease test
etc. (from table)