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| {{Uncurated}} | | <!--Do not edit or remove this line!-->{{MooreL}} |
| {{Biorealm Genus}} | | {{Biorealm Genus}} |
| ==Classification== | | ==Classification== |
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| ===Higher order taxa=== | | ===Higher order taxa=== |
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| Bacteria; Bacteroidetes; Flavobacteriia; Flavobacteriales; Flavobacteriaceae; Capnocytophaga [Use [http://www.ncbi.nlm.nih.gov/Taxonomy/ NCBI] link to find]
| | Domain; Phylum; Class; Order; family [Others may be used. Use [http://www.ncbi.nlm.nih.gov/Taxonomy/ NCBI] link to find] |
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| ===Species=== | | ===Species=== |
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| {| | | {| |
| | height="10" bgcolor="#FFDF95" | | | | height="10" bgcolor="#FFDF95" align="center" | |
| '''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Tree&id=2&lvl=3&lin=f&keep=1&srchmode=1&unlock Taxonomy]''' | | '''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&id=434&lvl=3&lin=f&keep=1&srchmode=1&unlock Taxonomy]''' |
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| 'Capnocytophaga canimorsus' | | ''Genus species'' |
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| ==Description and significance== | | ==Description and significance== |
| Capnocytophaga canimorsus is a capnophilic (carbon dioxide loving), facultative anaerobic rod shaped Gram-negative1 nonsporeforming bacterium.6 C. canimorsus is a zoonotic agent (causes interspecies infection) that has been isolated from humans following bite wounds, licks, scratches, and general exposure to dogs5, a lesser degree in cats, and rarely rabbits.1 The bacterium was first isolated in 1976 from a human following a dog bite and was initially named CDC group dysgenic fermenter DF-2 until 1989 it was given its current name.1,6 Millions of people worldwide suffer from animal bites. It has been estimated that out of the 50% of Americans who will be bitten by an animal in their lifetime, 90% of the bites will be inflicted by both dogs and cats.1
| | Describe the appearance, habitat, etc. of the organism, and why you think it is important. |
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| C. canimorsus has been documented to cause wound and systemic infection in humans. Although between the years 1976-2010 only 200 cases of Capnocytophaga infection were reported, severe clinical symptoms span a wide range including, but not limited to, septicemia, meningitis, osteomylitis, peritonitis, and endocarditis.1 If exposed to the bacterium, immunocompromised, asplenic, alcoholic, aged, and chronically diseased individuals are at higher risk of contracting infection even though infection has been observed in healthy individuals.1 Exposure and identification of C. canimorsus has proven difficult due to its fastidious nature, but recent PCR-restriction fragment length polymorphism (PCR-RFLP) species specific methods have detected the commensal bacterium in the oral flora of 74% of dogs.2
| | ==Genome structure== |
| | Describe the size and content of the genome. How many chromosomes? Circular or linear? Other interesting features? What is known about its sequence? |
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| According to a 2011-2012 American Pet Products Association survey there are 78.2 million dogs and 86.4 million cats owned in the United States alone which does not account for strays or shelter animals.3 The sheer number of dogs and cats warrants the study and characterization of C. canimorsus and other potential zoonotic microbes that make their home living commensally on household pets.
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| ==Genome structure== | | ==Cell and colony structure== |
| The genome of C. canimorsus Cc5, a strain isolated from a human sepsis patient, consists of a single circular replicon of 2,571,406 base pair, a guanine and cytosine content of 36.11%, and 2,405 coding sequences.4 The genome contains 46 tRNAs, three sets of rRNA, an RNase P, two tmRNAs, a TPP riboswitch, an SRP, a CRISPR region, and 206 lipoprotein genes.4
| | Interesting features of cell structure. |
| | Interesting features of colony structure. |
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| ==Cell and colony structure==
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| C. canimorsus are Gram-negative fusiform or filamentous rods1 measuring 0.45-0.6 µm in diameter and 2.5-5.7 µm in length8. In blood media, longer rods, curved filaments, spindle shaped, and coccoid forms have also been observed. Colonies range from pink to yellow, are initially pin-point in size (less than 0.5 mm in diameter) and are either convex or flat.1 Flat colonies tend to be irregularly shaped while convex colonies have a narrow and flat edge. After 48 hours of incubation the colonies grow larger (3.5 mm in diameter) and are raised displaying a shiny spreading edge as well as finger-like projections for gliding motility. The bacteria have no flagella6, motors, or pili and their movement has been called surface translocation.8
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| ==Metabolism== | | ==Metabolism== |
| Successful isolation of C. canimorsus is facilitated by specialized culture on heart infusion agar supplemented with 5% rabbit or sheep blood and incubation in a candle extinction jar (CO2).6 The bacterium requires high levels of iron in the culture media1 and although not obligately microaerophilic, thrives in a CO2-rich environment.6 Poor growth was recorded on routine screening media including Tryptic soy agar, Tryptic soy blood agar, LB agar8, MacConkey agar6, and triple sugar iron agar6. The anticoagulant polyanethole-sulfonate which is commonly used in automatic blood culture systems inhibits the growth of C. canimorsus.1
| | Energy source(s); external electron donor(s) (=reductant source(s)); carbon source(s); oxygen classification; important molecules it produces. |
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| Biochemical testing showed C. canimorsus to differ from other Capnocytophaga species because it tested positive for oxidase and catalase1, and esculin reactions.8 C. canimorsus also tested positive for arginine dihydrolase, ơ-nitrophenyl-β-Ɗ-galactopyranoside, and alkaline phosphatase.1,6 Acid production without gas was recorded from the breakdown of the fermentable substrates Ɗ-glucose, lactose, and maltose. Other fermentable sources include dextrin, Ɗ-galactose, glycogen, Ɗ-mannose, and starch. Acid production was negative when grown in the presence of inulin, raffinose, melibiose, and sucrose. Variable reactions were observed for nitrate reduction, esculing hydrolysis, and acid production from cellibiose and fructose.
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| ==Ecology== | | ==Ecology== |
| C. canimorsus grows in the oral flora of 26-74% of canines, 18-57% of felines, and rarely rabbits.7
| | Habitat; symbiosis; contributions to the environment. |
| | metagenomic data link |
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| ==Pathology== | | ==Pathology== |
| The oral flora of dogs is a highly competitive feeding ground for approximately 500 different bacterial strains.9 C. canimorsus is resistant to phagocytosis and killing by macrophages and blocks the killing of unrelated bacteria by macrophages. The bacterium exhibits robust growth when in contact with mammalian cells.10
| | Does this organism cause disease? Human, animal, plant hosts? Virulence factors. |
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| Due to sialidase and the polysaccharide utilization loci PCL5-encoded Gpd complex, C. canimorsus has been shown to sustain growth by evading host phagocytic cells and capturing amino-sugars off of their surfaces. Sialidase passes through the bacterium’s cytoplasmic membrane via the Sec pathway, crosses the outer membrane and remains attached. Although the mechanism of action is still being studied it has been shown that the Gpd genes associated with the complex consist of a specific outer membrane porin, a starch-binding protein, glycan binding proteins, and an endo-β-Ɲ-acetylglucosaminidase. The surface localized complex allows C. canimorsus to feed on glycan chains from the glycoproteins exposed on the surface of host epithelial cells and macrophages without adhering to them.10 The complex initiates a deglycosylation process for C. canimorsus metabolism. Sialidase might have evolved as a metabolic fitness factor contributing to commensalism in the canine and feline oral flora, but when the bacterium is exposed to a new host, the complex contributes to pathogenesis.5
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| Clinical Symptoms and Treatment
| | ==References== |
| | | [Sample reference] [http://ijs.sgmjournals.org/content/62/2/330; Sylvie Cousin, Marie-Laure Gulat-Okalla, Laurence Motreff, Catherine Gouyette, Christiane Bouchier, Dominique Clermont, and Chantal Bizet. Lactobacillus gigeriorum sp. nov., isolated from chicken crop. Int J Syst Evol Microbiol February 2012 62:330-334; published ahead of print March 18, 2011.} |
| Systemic symptoms arise 5-7 days prior to a dog bite.1 Initial symptoms range from localized cellulitis, pain, purulent discharge, lymphangitis, and regional lymphadenopathy. Septicemia symptoms include chills, mylagia, vomiting, diarrhea, dyspnea, abdominal pain, malaise, mental confusion, and headache. Immunocompromised individuals exposed to the bacterium are more susceptible than healthy persons to sepsis, meningitis, osteomylitis, peritonitis, endocarditis, pneumonia, purulent arthritis, disseminated intravascular coagulation, and fulminant purpura.1
| | [doi:10.1099/ijs.0.028217-0.] |
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| Medications that have been successful in vitro include penicillins, erythromycin, clindamycin, doxycycline, rifampin, quinolones, carbapenems, vancomycin, and third - generation cephalosporins, and amoxicillin/clavulanic acid because some beta-lactamase-producing strains have been isolated.7
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| ==References==
| | Edited by PUT YOUR NAME HERE of Dr. Lisa R. Moore, University of Southern Maine, Department of Biological Sciences, http://www.usm.maine.edu/bio |
A Microbial Biorealm page on the genus LRMoore, Univ of Southern Maine
Classification
Higher order taxa
Domain; Phylum; Class; Order; family [Others may be used. Use NCBI link to find]
Species
Genus species
Description and significance
Describe the appearance, habitat, etc. of the organism, and why you think it is important.
Genome structure
Describe the size and content of the genome. How many chromosomes? Circular or linear? Other interesting features? What is known about its sequence?
Cell and colony structure
Interesting features of cell structure.
Interesting features of colony structure.
Metabolism
Energy source(s); external electron donor(s) (=reductant source(s)); carbon source(s); oxygen classification; important molecules it produces.
Ecology
Habitat; symbiosis; contributions to the environment.
metagenomic data link
Pathology
Does this organism cause disease? Human, animal, plant hosts? Virulence factors.
References
[Sample reference] [http://ijs.sgmjournals.org/content/62/2/330; Sylvie Cousin, Marie-Laure Gulat-Okalla, Laurence Motreff, Catherine Gouyette, Christiane Bouchier, Dominique Clermont, and Chantal Bizet. Lactobacillus gigeriorum sp. nov., isolated from chicken crop. Int J Syst Evol Microbiol February 2012 62:330-334; published ahead of print March 18, 2011.}
[doi:10.1099/ijs.0.028217-0.]
Edited by PUT YOUR NAME HERE of Dr. Lisa R. Moore, University of Southern Maine, Department of Biological Sciences, http://www.usm.maine.edu/bio
