Difference between revisions of "Helicobacter"

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<big><center>[[Infectious agents and parasites|'''BACK TO INFECTIOUS AGENTS AND PARASITES''']]</center></big>
==Overview==
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<big><center>[[Bacteria|'''BACK TO BACTERIA''']]</center></big>
[[File:EMpylori.jpg||200px|thumb|right|''H. pylori'' - Yutaka Tsutsumi, M.D. Professor Department of Pathology Fujita Health University School of Medicine, Wikimedia Commons]]
 
''Helicobacter spp.'' are related to [[:Category:Campylobacter species|''Campylobacter'']] species and ''Arcobacter'' species and are pathogens affecting the [[:Category:Stomach|stomach]]. Unlike many bacterial pathogens, ''Helicobacter spp.'' are able to survive in the extremely low pH environment that exists within the stomach. The genus was first discovered in the stomach of humans in 1987.
 
  
There are several species identified in humans and many veterinary species where the incidence of some species of ''Helicobacter'' is high. Species such as ''H. pylori'', ''H. felis'', ''H. bizzozeronii'', ''H. salomonis'' and ''H. bilis'' have been identified in the gastric mucosa and intestines of dogs and cats.
 
  
The genus is however considered of '''low pathogenic significance''' in veterinary species but there is possibility of '''zoonosis''' of the ''H. pylori'' species that is the causative agent of gastric disease in humans. The organism infects humans causing gastritis as well as gastric and duodenal ulcers. It has also been associated with gastric adenocarcinoma however there is no evidence for this in animals. ''H. pylori'' has not been identified in cats and is rarely seen in cats.
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===Overview===
  
The major veterinary concern posed by ''Helicobacter spp.'' is the ''H. mustelae'' that has been associated with '''chronic gastritis and gastric ulcers in ferrets'''.
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*Related to ''Campylobacter'' species and ''Arcobacter'' species
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*A [[Intestine Pathogens - Pathology#|bacterial pathogen of the intestines]]
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*Discovered in the stomach of humans in 1987
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*''H. felis'', ''H. bizzozeronii'', ''H. salomonis'' and ''H. bilis'' found in gastric mucosa and intestines of dogs and cats
  
==Characteristics==
 
''Helicobacter'' are gram negative rod bacteria, they can appear helical, S-shaped or curved. All species except ''H. canis'' are oxidase and catalase positive. Species of ''Helicobacter'' that colonise the gastric mucosa are '''urease positive''' as they must produce the enzyme to create a local environment with a pH of about 6-7 in order to survive.
 
  
They require enriched media, are microaerophilic and non-saccharolytic; some grow on Skirrow agar.
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===Characteristics===
  
==Clinical Infections==
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*Helical, S-shaped or curved Gram negative rods
The significance of ''Helicobacter spp.'' in gastointestinal disease of domestic carnivores is unknown.
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*Require enriched media; some grow on Skirrow agar
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*Microaerophilic, non-saccharolytic
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*Oxidase positive and catalase positive except for ''H. canis''
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*Helicobacters which colonise gastric mucosa are urease positive
  
Up to '''80% of clinically healthy dogs''' have ''Helicobacter spp.'' present, several species have been identified in the dog such as; ''H. felis'', ''H. bizzozeronii'', ''H. salomonis'' and ''H. bilis''. Experimental infection of dogs has failed to show a consistent relationship between infection with ''Helicobacter'' and the development of pathology.
 
  
The only species known to be of veterinary importance is ''H. mustelae'' which has been associated with chronic gastritis and gastric ulcers in ferrets. Ferrets suffer from '''vomiting, melena, weight loss and lowered haematocrit'''. It has also been associated with the development of pyloric [[adenocarcinoma]] and mucosa-associated [[lymphoma]] of the stomach.
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===Clinical infections===
  
==Diagnosis==
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*''Helicobacter pylori'' causes gastritis and duodenal and gastric ulcers in humans
'''Cytology''' from a brushing during gastric endoscopy can be performed to visualise the organism under oil immersion microscopy.
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*Association with gastric adenocarcinoma in humans
 
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*''H. mustelae'' has been associated with chronic gastritis and gastric ulcers in ferrets
A '''urease test''' can be performed by placing gastric biopsy samples into a urease broth and observing a positive result.
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*Significance in gastrointestinal diseases of domestic carnivores not known
 
 
'''Gastric biopsies''' can also be cultured in special media to isolate and grow ''Helicobacter'' spp.
 
 
 
'''[[PCR]]''' has recently been developed to demonstrate the organism in samples.
 
 
 
==Treatment==
 
The decision to treat for ''Helicobacter'' infections should be made on the basis of the degree of inflammation seen in the gastric mucosa of dogs in response to the organism. Treatment should lead to a resolution in inflammation and elimination of the organism.
 
 
 
'''Triple therapy''' using: '''amoxycillin and metronidazole''', or tetracycline and metronidazole, combined with '''bismuth subsalicylate''' given for 2-3 weeks is usually successful in eradicating the infection. The addition of '''ranitidine or omeprazole''' can also be considered if [[Stomach Ulcer|ulcers]] are present.
 
 
 
This is also effective in ferrets infected with ''H. mustelae''.
 
 
 
{{Learning
 
|flashcards = [[Small Animal Abdominal and Metabolic Disorders Q&A 15]]
 
}}
 
 
 
==References==
 
Macpherson, C. (2000) '''Dog zoonoses and public health''' ''CABI''
 
 
 
Hirsh, D. (2004) '''Veterinary microbiology''' ''Wiley-Blackwell''
 
 
 
Schaer, M. (2010) '''Clinical medicine of the dog and cat''' ''Manson Publishing''
 
 
 
 
 
{{review}}
 
 
 
{{OpenPages}}
 
 
 
[[Category:Gastric Diseases - Dog]]
 
 
 
 
 
[[Category:Bacteria miscellaneous]][[Category:Rods]][[Category:Gram_negative_bacteria]]
 
[[Category:Enteritis,_Bacterial]]
 
[[Category:Expert Review - Exotics]]
 
[[Category:Ferret Diseases]]
 

Revision as of 22:47, 25 August 2008

BACK TO INFECTIOUS AGENTS AND PARASITES
BACK TO BACTERIA


Overview

  • Related to Campylobacter species and Arcobacter species
  • A bacterial pathogen of the intestines
  • Discovered in the stomach of humans in 1987
  • H. felis, H. bizzozeronii, H. salomonis and H. bilis found in gastric mucosa and intestines of dogs and cats


Characteristics

  • Helical, S-shaped or curved Gram negative rods
  • Require enriched media; some grow on Skirrow agar
  • Microaerophilic, non-saccharolytic
  • Oxidase positive and catalase positive except for H. canis
  • Helicobacters which colonise gastric mucosa are urease positive


Clinical infections

  • Helicobacter pylori causes gastritis and duodenal and gastric ulcers in humans
  • Association with gastric adenocarcinoma in humans
  • H. mustelae has been associated with chronic gastritis and gastric ulcers in ferrets
  • Significance in gastrointestinal diseases of domestic carnivores not known