VMC 311: Systematic Veterinary Bacteriology and Mycology (2+1)

HABITAT AND MORPHOLOGY

Habitat

• B. nodosus are obligate anaerobic bacteria of the digital epidermis of sheep under normal climatic conditions.
• They will not survive on pastures for more than a week.
• Other Bacteroides species can be normal inhabitants of the skin, mucous membrane and G.I. tract of domestic animals.
• Fusobacterium species occurs as a commensal in the alimentary tract and mucous membranes of a variety of animals.

Morphology

• Bacteroides nodosus appear as Gram-negative, fairly large (1.7 x 3-6 µm), slightly curved and non-motile rods.
• Often swollen at one or both ends. They occur singly or occasionally in pairs
• Fusobacterium necrophorum is Gram-negative, long and filamentous but does not branch.
• Filaments can be up to 100 µm in length and 0.5-0.7 µm in diameter.
• May have tapered or rounded ends. Irregular staining is characteristic