DR.T.V.RAO MD 1
Dr.T.V.Rao MD
HELICOBACTER PYLORIUPDATE
HISTORY OF H. PYLORI• 1890’s: Spirochetes in animal stomachs
• 1900’s: Spirochetes in human stomachs
• 1954: No bacteria in gastric biopsies of 1000 patients
• 1975: Gram negative bacteria in 80% of GU’s (Pseudomonas)
• 1983: Warren and Marshall characterize H. pylori
• 2005 Nobel prize in 2005
DR.T.V.RAO MD 3
HELICOBACTER PYLORI
Background
Human stomach long considered inhospitable forbacteria
Spiral shaped organisms occasionally visualized ingastric mucous layer, but no evidence of diseaseassociation
Organism classified first as Campylobacter pylori
Now Helicobacter pylori
Other species of Helicobacter isolated fromstomach, intestine of other animals
Marshall and Warren culture organism from humangastric mucosa and show association with gastricinflammation
DR.T.V.RAO MD 4
HELICOBACTER( WARREN AND MARSHAL )
• Campylobacter like organisms
• Spiral shaped colonizes Gastric mucosa
• Etiological agent in Gastritis and peptic ulcer
• Most important bacteria.
Helicobacter pylori
Colonizes 50 % of the Individuals
DR.T.V.RAO MD 5
WARREN AND MARSHAL WINS NOBEL PRIZE
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GENERAL CHARACTERISTICS OF HELICOBACTER
• Helicobacter pylori is major human pathogen associated with gastric antral epithelium in patients with active chronic gastritis
• Stomach of many animal species also colonized
• Urease (gastric strains only), mucinase, and catalase positive highly motile microorganisms
• Other Helicobacters: H. cinnaedi and H. fenneliae
• Colonize human intestinal tract
• Isolated from homosexual men with proctitis, proctocolitis, enteritis, and bacteremia and are often transmitted through sexual practices
DR.T.V.RAO MD 7
A silver stain of H. pylori on gastric mucus-secreting epithelial cells (x1000).
From Dr. Marshall's stomach biopsy taken 8 days after he drank a culture of H. pylori
(1985).
HELICOBACTER PYLORI
• Gram –ve spiral shaped , motile with unipolar tuft of lopotrichus flagella
DR.T.V.RAO MD 8
H. PYLORI BACTERIA
• Gram negative
• Spiral rod
• Unipolar flagella
• Microaerophilic
• Urease positive*
*Most important
character
*Scanning microscopic view of H. pylori
MORPHOLOGY & PHYSIOLOGY OF HELICOBACTER
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• Gram-negative; Helical (spiral or curved) (0.5-1.0 um X 2.5-5.0 um); Blunted/rounded ends in gastric biopsy specimens; Cells become rod-like and coccoid on prolonged culture
• Produce urease, mucinase, and catalase
• H. pylori tuft (lophotrichous) of 4-6 sheathed flagella (30um X 2.5nm) attached at one pole
• Single polar flagellum on H. fennellae & H. cinaedi
• Smooth cell wall with unusual fatty acids
• Transmissible• Oral-oral and oral-fecal
• Infects the human stomach
• Produces inflammatory response
• This brings up the point of the importance of “hand washing”
H. PYLORI INFECTION TRANSMISSION
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DYNAMICS OF H.PYLORI INFECTION
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CULTURING AND BIOCHEMICAL CHARACTERS
• Grows on chocolate agar, Campylobacter media
• Grows under Microaerophilic conditions
• With presence of 5 – 20% co2
• Oxidase +
• Catalase –
• Urease strongly +++
• H2S
H. PYLORI PATHOGENESISBACTERIAL VIRULENCE FACTORS
(CAG- PAI)( 37000 B-P – 29 GENES)
• Type IV secretions apparatus(1) (translocate cag A)
• Possible insertion by needle like organelle coated with a sheath (Cag 7 protein) [Rohde et al]
• Phosphorylated + binds to SHP-2 tyrosine Phosphates
Cytokine Production Growth Factor
IL- 8+ chemokines Like cellular response
(1) Odenbreit S, et al. Science 2000;287:1497-1500
H. PYLORI PATHOGENESISBACTERIAL VIRULENCE FACTORS
Ingestion Evasion + Entrance of Mucus
1 Layer (Motility + Urea I)
2 Binding
3 Insertion
4 Intra cellular pathway
HELICOBACTER PYLORI AND PEPTIC ULCER DISEASEHISTOPATHOLOGY WITH SPECIAL STAINS .
DR.T.V.RAO MD 17
H. PYLORI PATHOGENESISTHE ROLE OF CYTOKINES
I. Alter secretion of mucus
II. TNF–α IL–Iß, INF- 1Y
• ↑ Gastrin release Stimulate parietal cells
↑ Acid secretion
III. TNF–α ↓ D cells number
↓ Somatostatin
↑ Acid secretion
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PATHOLOGY AND PATHOGENESIS• H.pylori colonizes gastric mucosa• Spread by oral – oral contact• Feco oral spread prominent• Poverty and overcrowding predisposes• Poor Hygiene• Causes mild to acute gastritis • Gastric antrum - causes gastric metaplasia• Any part of the stomach can be involved• Colonizes overlying mucosa but donot invade mucosa
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MAJOR LOCATION OFH.PYLORI INFECTIONS
Colonize mucosal lining of stomach & duodenum in man & animals • Adherent to gastric surface epithelium or pit epithelial
cells deep within the mucosal crypts adjacent to gastric mucosal cells
• Mucosa protects the stomach wall from its own gastric milleu of digestive enzymes and hydrochloric acid
• Mucosa also protects Helicobacter from immune response
Most gastric adenocarcinomas and lymphomas are concurrent with or preceded by an infection with H. pylori
Pathogenesis of Helicobacter Infections
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H.PYLORI INFECTING MUCOSAL LAYER
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PATHOGENESIS OF H.PYLORI.
Multiple polar, sheathed flagella• Corkscrew motility enables penetration into viscous
environment (mucus)
Adhesins: Hemagglutinins; Sialic acid binding adhesin; Lewis blood group adhesin
Mucinase: Degrades gastric mucus; Localized tissue damage
Urease converts urea (abundant in saliva and gastric juices) into bicarbonate (to CO2) and ammonia• Neutralize the local acid environment• Localized tissue damage
Acid-inhibitory protein
Virulence Factors of Helicobacter
H. Pylori Specific T Cell and B Cell Responses
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MECHANISM OF H.PYLORI INFECTION
Urease C=O(NH2)2 + H+ + 2H2O HCO3
- + 2 (NH4+)
Urea Bicarbonate Ammonium ions
And then… HCO3-
CO2 + OH-
Urea Hydrolysis
Tissue damage: Vacuolating cytotoxin: Epithelial cell damage Invasin(s)(??): Poorly defined (e.g., hemolysins;
phospholipases; alcohol dehydrogenase)
Protection from phagocytosis & intracellular killing: Superoxide dismutase Catalase
Virulence Factors of Helicobacter )
H. Pylori Pathogenesis and Application of Cutting Edge Technologies
Molecular biology
Genetics Imaging Cell culture models
INDICATIONS FOR NONINVASIVE TESTING FOR H. PYLORI *
• Strongly Recommended• Dyspepsia
• History of/active peptic ulcer disease
• Gastric MALT lymphoma
• Following gastric cancer resection
• Following peptic ulcer surgery
• First-degree relative with gastric cancer
• Long-term Non-steroidal anti-inflamatory drugs (NSAID) therapy
* In the absence of alarm signs for gastric cancer or ulcer disease1. Malfertheiner P, et al. Aliment Pharmacol Ther. 2002;16:167. 2. Talley NJ et al. Aliment Pharmacol Ther.1999;12:1135.
TYPES OF H. PYLORI TESTS
• Endoscopy
• Rapid urease tests
• Histology
• Culture
• Serologic (antibody)
• Stool antigen tests
• 13C Urea blood test• Urea breath tests
•14C-urea
•13C-urea
Malfertheiner P, et al. Aliment Pharmacol Ther. 2002;16:167.
• Detects active infection
• Sensitive and specific
• Non-radioactive
• No special handling requirements
• Easy to collect and handle sample
• Not indicated in pediatric population
13C UREA BREATH TEST
1. Graham DY et al. Am J Gastroenterol. 2001;96:1741. 2. Leodolter A et al. Am J Gastroenterol. 1999;94:2100.
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LABORATORY DIAGNOSIS• Diagnosed by Invasive and Non Invasive tests• Invasive, Endoscopic Biopsy of Gastric mucosa• Microscopy – Biopsy• Culture • Staining by special stains• Gram staining• Culture more sensitive 3 – 7 days• Biopsy testing for urease detection in urea medium
Laboratory IdentificationRecovered from or detected in endoscopic antral
gastric biopsy material; Multiple biopsies are takenMany different transport media Culture media containing whole or lysed bloodMicroaerophilicGrow well at 37oC, but not at 25 nor 42oCLike Campylobacter, does not use
carbohydrates, neither fermentatively nor oxidatively
DIAGNOSIS BY NON INVASIVE METHODS
• Serology ELISA
• Urea breath test patient swallows urea solution
In this test patient drinks urea solutions labeled with an isotope carbon
If H.pylori is present in the urea is converted to ammonia and co2 in the breath measured.
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SUGGESTED GUIDELINES FORTREATMENT OF PATIENTS WITH GI OR ULCER
DISEASE
History & Physical Exam
Peptic ulcerdisease
Undifferentiateddyspepsia
Symptomsof GERD
Use of NSAIDsor aspirin
Positive
Eradicationtherapy
Confirmation of cure
Test for H. pylori
Malfertheiner P, et al. Aliment Pharmacol Ther. 2002;16:167.
SUGGESTED GUIDELINES FORTREATMENT OF PATIENTS WITH GI OR ULCER
DISEASE
History & Physical Exam
Peptic ulcerdisease
Undifferentiateddyspepsia
Symptomsof GERD
Use of NSAIDsor aspirin
Positive
Eradicationtherapy
Confirmation of cure
Negative
Treat for PUD,Initiate PPI therapy,
or discontinue NSAIDs
Test for H. pylori
Malfertheiner P, et al. Aliment Pharmacol Ther. 2002;16:167.
DR.T.V.RAO MD 38
TREATMENT
• Use of antibiotics, bismuth salts• Ingestion of Bismuth subsalicylate• Antibiotics Tetracycline's and metronidazole for two weeks• Use of Omeprazole• Clarithromycin• Do not treat for Asymptomatic colonization• Drug resistance is a growing problem
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• Antibiotic treatment does not always completely inhibit or kill H. pylori with potential for antibiotic resistance. Resistance to antibiotics is the single most important factor for declining H. pylori eradication rates.
• In Japan, resistance to antibiotic drugs has increased 400% while in Taiwan, it is 500%. This means that those who are infected while in these countries may find the bacterium rather resistant to their antibiotic treatments.
EMERGING DRUG RESISTANCE IN H.PYLORI
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EPIDEMIOLOGY OF HELICOBACTER INFECTIONS
• Developed Countries:
• United States: 30% of total population infected
• Of those, ~1% per year develop duodenal ulcer
• ~1/3 eventually have peptic ulcer disease(PUD)
• 70% gastric ulcer cases colonized with H. pylori
• Low socioeconomic status predicts H. pylori infection
• Developing Countries:
• Hyperendemic
• About 10% acquisition rate per year for children between 2 and 8 years of age
• Most adults infected but no disease
• Protective immunity from multiple childhood infections
H.PYLORI CONTINUES TO BE AN IMPORTANT PATHOGEN
• H. pylori is a transmissible, infectious disease with potentially serious outcomes
• H. pylori infection may be asymptomatic or cause dyspepsia
• Eradication therapy can cure H. pylori infection and prevent morbidity and downstream events such as PUD and gastric cancer
• Patients with symptoms of upper-GI disease, and who use aspirin or NSAIDs should be tested for H. pylori infection
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• Programme Created by Dr.T.V.Rao MD for Medical and Health Care Workers in
the Developing World• Email
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