Gram – Negative Zoonotic Rods Flashcards
4 medically important genera:
Brucella
Pasteurella
Francisella
Yersinia
Reservoir: cows
B. abortus
Reservoir: goats
B. melitensis
Reservoir: goats
B. melitensis
Reservoir: pigs
B. suis
Reservoir: dog
B. canis
Virulence Factors of Brucella spp.
- Capsule
- Tropism to erythritol
Transmission:
- Direct contact with contaminated livestock or aborted placentas.
- Ingestion of infected milk.
- Inhalation of organisms.
Brucella spp.
- Diurnal fever – “Undulant fever”
- Non – specific signs and symptoms
- weakness - sweats
- anorexia - malaise - Organomegaly – splenomegaly, hepatomegaly and lymphadenopathy
Brucellosis/ Bang’s Disease
Induces abortion in animals
Brucella spp.
Rod to coccoid –shaped, arranged singly or in pairs –“appearance
of a sand”
Brucella spp.
- slow growing
- growth enhanced by 5 to 10 % CO2
Brucella spp.
Culture for Brucella spp.
i. Blood Agar Plate (BAP) – incubate for 4- 6weeks
ii. MacConkey Agar
iii. Brucella Agar
• Facultative anaerobe
• Non – motile
• Range morphologically from coccobacilli to long filamentous rods
• Found as commensals in the upper respiratory tract of fowl and mammals
Pasteurella spp.
most important human pathogen of Pasteurella spp.
Pasteurella multocida