Transcript Helicobacter

Helicobacter
http://www.cdc.gov/ulcer/psas.htm
• First one discovered in 1983 by Drs. Barry
Marshall and J. Robin Warren
• Originally classified as a Campylobacter
• 22 species have now been discovered
• The six that are associated with human
disease are : H. pylori, H. cinaedi, H.
fennellia, H. canadensis, H. canis, and
H. pullorum
• Table 33-3
Physiology and Structure
• Gram(-) spiral
• Characterized by the 16s rRNA genes,
fatty acids, and polar flagella on each end
• Have bacillary or spiral shape in young
cultures but take on a coccoid shape in
older cultures
• Requires microaerophilic environment with
enriched medium agar and temperature
must be between 30-37°C
Diseases
• Helicobacters are divided into two groups
• Table 33-3
– Gastric
• H. Pylori
– Enteric
• Other five bacterium
– All cause gastroenteritis
– H. fennelliae and H. cinaedi have been isolated from
homosexual men with proctitis, proctocolitis and enteritis
– Most of these diseases are uncommon and rare
H. Pylori
• 50% of the world population is infected
– 70-90% in developing countries, usually before 10 years
– Infections are much lower in the U.S.
» About 45% of older adults are infected
» More common in older adults, African Americans,
Hispanics, and people with lower socioeconomic
status
• Cause peptic ulcers, duodenal ulcers,
acute and cronic gastritis
– Associated with almost 100% of all gastritis infections
– 90% of duodenal ulcers, 80% of gastric ulcers
– Persons with infection have a six fold greater chance of
developing gastric cancer and MALT lymphoma
Transmission
• The actual mode of transmission is not yet
known
– CDC believes that it is by fecal-oral, or oraloral routes
– There have been incidents of transmission
from contaminated endoscopes
– A possible reservoir for H. pylori is
contaminated water
Prevention and Control
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Wash hands
Eat properly prepared food
Drink clean water
A vaccine is in development
– Bacteria appears to help prevent
gastroesophageal (acid) reflux disease
adenocarcinomas of the lower esophagus, so
there is a question of whether to treat people
that are asymtommatic
Diagnosis
• Microscopy
– Gold standard
– Invasive test
• Urease Test
– Breath analysis
• Antigen detection
– Stool specimen
• Culture
– Invasive procedure
– Experienced microbiologists are more successful at culturing
bacteria
• Serology
– Dignostic test of choice
Virulence factors
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Urease
Heat shock protein
Acid-inhibitory protein
Flagella,
Adhesins,
Mucanase,
Phospholipases,
Superoxide dismutase,
Catalase,
Vacuolationg Cytotoxin.
– Table 33-4
Treatment
• Combination of antibiotics, H2 pump
inhibitor, and bismuth
• Triple therapies work better than double
and longer use of the therapy help with the
eradication
• FDA has eight different treatments
• http://www.cdc.gov/ulcer/md.htm
• H.pylori images courtesy of
www.hpylori.com.au
• www.cdc.gov
• Medical Microbiology, Patrick R. Murray,
Elsevier Mosby, 2005, pg. 350-354