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Bacteriodes
Bacteriodes
28
Microbiology
Undergraduate 3
05/07/2012

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Term
Most frequently isolated Bacteriodes pathogen from clinical samples:
Definition
Bacteriodes fragilis.
Term
Bacteriodes fragilis characteristics:
Definition
Faint staining GRN. Safety pin shape. Anaerobe. Aerotolerent. Contains functional catalase.
Term
NTBF stands for:
Definition
Nonenterotoxigenic Bacteriodes fragilis.
Term
ETBF stands for:
Definition
Entertoxigenic Bacteriodes fragilis.
Term
NTBF characteristics:
Definition
Significant opportunistic pathogen.
Perforations in the colon can lead to intra-abdominal abscesses.
Bacteremia.
Term
ETBF characteristics:
Definition
Primary pathogen.
Diarrheal disease.
Term
Virulence Factor of NTBF - LPS:
Definition
Very low endotoxin activity (1000x less than E. coli)
- because LPS lacks classical O-antigen structures.
Term
Virulence Factor of NTBF - Capsule:
Definition
8 different polysaccharides (PSA - PSH)
Adherence to peritoneal surfaces.
Can induce abscess formation outside colon.
Inhibits phagocytosis.

It is the most complex polysaccharide capsule system.
Term
Virulence Factor of NTBF - Fimbriae:
Definition
Binds to:
- Fibrinogen.
- Fibronectin.
- Lactoferrin.
Term
Virulence Factor of NTBF - Protease:
Definition
Degrades complement components.
- similar to S. pyogenes SpeB.
Term
Virulence Factor of ETBF - Bacteriodes fragilis Toxin (BFT):
Definition
AKA - Fragilysin.

- heat-labile zinc metalloprotease.
- cleaves E-cadherin - increases intracellular permeability.
-produces morphological changes in the intestinal epithelium.
- chloride secretion with subsequent fluid loss.
- induces an inflammatory response.
Term
Virulence Factor of ETBF - encoded by the BFT gene - found where?
Definition
Found on conjugative transposon in pathogenicity island (BfPAI)
Term
B. fragilis identification on AnaBAP:
Definition
No pigmentation.
No beta hemolysis.
Term
B. fragilis identification on BBE:
Definition
Growth stimulated by bile salts.
Resistant to gentamycin.
Esculin is hydrolyzed.
Term
B. fragilis is highly drug resistant - resistant to:
Definition
Kanamycin.
Vancomycin.
Colistin.
Penicillins (Beta-lactamase producer)
Term
B. fragilis - Glucose fermenter?
Definition
Yes.
Term
Second most common anaerobic isolates:
Definition
Prevotella and Porphyromonas.
Term
Prevotella and Porphyromonas are found as normal flora where?
Definition
Oral cavity.
Upper and lower GI.
Female uro-genital tract.
Term
Prevotella and Porphyromonas clinical conditions:
Definition
Sinusitis.
Otitis media - Chronic.
Periodontal infections.
Brain abscesses.
Female uro-genital tract infections.
Term
Prevotella and Porphyromonas Gram reactions and morphology:
Definition
Both are Gram Negative coccobacilli.
Term
Prevotella and Porphyromonas produce what kind of protein?
Definition
Proteases that degrade IgG.
Term
Prevotella and Porphyromonas - one ferments glucose, one does not:
Definition
Prevotella spp. ferment glucose.

Porphyromonas spp. do not.
Term
Prevotella and Porphyromonas AnaBAP reactions:
Definition
Pigment is produced.

Initially: colonies are tan to buff and fluoresce brick red.
Later: colonies become brown to black.

Often described as having a "foul odor"
Term
Fusobacterium nucleatum is normal flora where?
Definition
Oral cavity - gingival smears.
Upper respiratory tract.
GI tract.
Term
Conditions caused by F. nucleatum:
Definition
Can contribute to periodontitis.
Sinusitis.
Brain abscesses.
Intra-abdominal infections.
Liver abscesses.
Term
Gram stain of F. nucleatum shows:
Definition
Slender GNR with pointed ends.
Term
AnaBAP of F. nucleatum shows:
Definition
non-pigmented microbe.
Term
F. nucleatum on Egg Yolk Agar:
Definition
Lipase production may be seen.
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