Fusobacterium and Bacteroides Flashcards
What kind of bacteria are Fusobacterium and Bacteroides?
Non-sporeforming, Gram-negative anaerobic bacilli
Where are non-sporeforming anaerobes commonly found in animals?
Mucous membranes and intestinal tract
What percentage of intestinal flora are Gram-negative anaerobic bacilli?
Over 90%
especially predominant in large bowel and ruminal flora
Fusobacterium sp. commonly found in alimentary tract and mucous membranes of animals? Characterized as Gram-negative rods, short rods, long filaments, & moniliform bodies.
Fusobacterium necrophorum
Which biotypes of F. necrophorum cause liver abscesses in Cattle?
A and B
What are the 4 biotypes of F. necrophorum?
A, B, AB, and C
Which biotype of F. necrophorum is more virulent, A or B?
A
What is the current classification of Biotype C?
Fusobacterium varium
(formerly F. pseudonecrophorum)
What subspecies correspond to Biotype A of F. necrophorum?
F. necrophorum subsp. necrophorum
What subspecies correspond to Biotype B of F. necrophorum?
F. necrophorum subsp. funduliforme
How does F. necrophorum invade tissue?
Multiplies in anaerobic environments provided by damaged tissues
Key virulence factors of F. necrophorum? (8)
APaf PD HELH
1.) endotoxin
2.) leukotoxin
3.) hemolysin
4.) hemagglutinin
5.) adhesin
6.) platelet aggregation factor
7.) protease
8.) DNase
What strains are more virulent?
Capsulated strains
In which animal does F. necrophorum cause the following diseases?
- liver abscesses
- foot rot
- calf diphtheria
- metritis
- mastitis
- cellulitis
Cattle
In which animal does F. necrophorum cause the following diseases?
- thrush (hoof)
- pneumonia
- septicemia
Horse
In Swine, what condition is F. necrophorum associated with?
“Bull nose” from ringing injuries
What is the general term for infections caused by F. necrophorum?
Necrobacillosis
Appearance of F. necrophorum colonies?
- small, convex, smooth
- whitish yellow
- narrow hemolysis zone
How does F. necrophorum interact with Archanobacterium pyogenes (Trueperella pyogenes)?
Acts synergistically in mixed infections (liver abscesses, ovine foot abscesses)
What are effective treatments for F. necrophorum?
- amoxicillin
- ampicillin
- tetracyclines
- metronidazole
- clindamycin
- cephalosporins
- tylosin (additive)
Is vaccination against F. necrophorum effective, Yes or No?
No
How many species are in the Bacteroides fragilis group?
10 species
Where are B. fragilis group species commonly recovered from?
Clinical specimens in humans and animals
What toxins does B. fragilis produce?
- endotoxin
- enterotoxin: fragilysin & a zinc metalloprotease
