Helicobacter Pres

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HelicobacterRabia Chaudhry


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Historical Background 1892: Italian pathologist Giulio Bizzozero first

described spirilli in dogs stomach

Several reports over the next century 1954: Palmer biopsy study established dogma

of sterile stomach environment

1979: Robin Warren found spiral bacteria inhuman stomach; association with gastritis

1983: Barry Marshall isolated and culturedbacteriaBizzazeros original drawings

(Figura, 2002)


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Historical Background Initially named Campylobacter pylori

1985 - 1987: Marshall and Morris inoculatedthemselves and developed gastritis

1989: New spiral bacteria named Helicobacterpylori

Scientific community extremely slow toaccept link between H. pyloriand peptic ulcerdisease

2005: Warren and Marshall win Nobel Prize H. heilmanniiin a patient withdyspepsia (Figura, 2002)


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A New Genus: Helicobacter Currently has 18 formally validated species

Non-spore forming, Gram negative, motile,spiral/ curved, microaerophilic bacteria

Human stomachs are primarily colonized byHelicobacter pylorias well as H. heilmanniito alesser degree

Nearly all mammals have associatedHelicobacter species e.g. H. felis (cats and dogs)

and H. mustelae (ferrets)

Infection of a mammal from a differentHelicobacter species is possible

H. pyloriand H. felis (Mobley, 2001)


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Helicobacter pylori Causes gastritis; correlated with peptic ulcers

and progression to cancer

Present in roughly half the worlds population

Most infections are asymptomatic

Most common human infectious agent; higherprevalence in developing regions

Often colonizes lower stomach or upperduodenum; named after pylorus

Colonizes host for life; well adapted to stomachniche environment


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H. pylori: Pathogenisis Propels itself to the mucus layer

Protects itself from stomach acids byproducing urease during transmission

Colonizes the gastric mucosa and mucuslayer of the gastric epithelium

Inflammation of the gastric mucosaprovides nutrients as well as urea

Has a number of adhesion capabilitiesand molecular mimicry techniques to

evade immune systemMontecucco, 2001


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H. pylori: Detection & Treatment

Non invasive: Urea breath testing,ELISA, Stool antigen testing

Invasive: endoscopic biopsy to obtaintissue sample; identification, culture

and PCR

Various antibiotic regimens to treatthe infection

No vaccines have been developedyet


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H. pyloriTransmission Infective dose (data from Rhesus monkeys): 10^4

Animals and water potential environmental sources

- Studies about animal hosts inconclusive

- Never been cultured from water; maybe VBNC.

- PCR techniques have detected H. pylori in environmental water; viable?

Person-to-person most likely more important; not sure how

- Gastro-oral, oral-oral or fecal-oral

- Mixed results for trying to culture


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Current Research Areas

Pathogenicity of H. pylori resultingin many asymptomatic cases

Transmission routes

Mechanisms of gastric cancer

Understanding of viability and

infectivity outside the gastric

environment


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Five Things to Remember H. pylori first isolated and cultured by Warren and

Marshall in 1983

Can cause gastritis, peptic ulcers and cancer

Half the worlds population is infected but many areasymptomatic

Protects itself against stomach acid by secreting urease Can be treated with antibiotics; no vaccine yet


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ReferencesFigura, N., Bianciardi, L. (2002). Helicobacters were discovered in Italy in 1892: AN episode in the scientific life of an eclectic pathologist,

Giulio Bizzozero. In B. Marshall (Ed.),Helicobacter Pioneers (pp. 1-11). Victoria, Australia: Blackwell Science Asia Pty Ltd.

Fukuda, Y., Shimoyoma, T., Shimoyoma, T., Marshall B. J. (2002) Kasai, Kobayashi and Kochs postulates in the history ofHelicbacter pylori . In

B. Marshall (Ed.),Helicobacter Pioneers (pp. 15-23). Victoria, Australia: Blackwell Science Asia Pty Ltd.

Giao, M. S., Azevedo, N. F., Wilks, S. A., Vieira, M. J., Keevil, C. W. (2010). Effect of Chlorine on Incorporation of Helicobacter pylori into

Drinking Water Biofilms.

Applied And Environmental Microbiology, 76 (5), 16691673.

Marshall, B. J. (2002). The discovery thatHelicobacter pylori, a spiral bacterium, caused peptic ulcer disease. In B. Marshall (Ed.),Helicobacter

Pioneers (pp. 165-201). Victoria, Australia: Blackwell Science Asia Pty Ltd.

Mobley, H. L.T., Mendz, G. L., Hazell, S. L., (Ed.). (2001).Helicobacter pylori . Washington (DC): American Society for Microbiology Press.

Montecucco, C., Rappuoli, R. (2001).Living dangerously: how helicobacter pylori survives in the human stomach . Nature Reviews Molecular

Cell Biology, 2, 457-466.

Solnick, J. V., Hansen, L. M., Canfield, D. R., Parsonnet, J. (2001). Determination of the Infectious Dose of Helicobacter pylori during Primaryand Secondary Infection in Rhesus Monkeys (Macaca mulatta).Infection and Immunity, 69 (11), 6887 6892.

Yamamoto, Y., Friedman, H., Hoffman, P. (2002). Helicobacter pylori Infection and Immunity. New York, NY: Kluwer Academic/ Plenum

Publishers.

Yamaoka, Y. (2008).Helicobacter pylori: Molecular genetics and cellular biology. Norfolk, UK: Caister Academic Press.

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