4. • Erysipelothrix rhusiopathiae is the type species of
the genus and is the species of primary
importance.
• It causes a disease called erysipelas in domestic
animals, especially swine.
• In humans, a self-limiting infection of the skin is
caused, called erysipeloid.
• Erysipelothrix tonsillarum is occasionally involved
in clinical disease but is nonpathogenic for swine.
5. MORPHOLOGY AND STAINING
•Erysipelothrix rhusiopathiae is a straight or
slightly curved
• gram-positive
• nonmotile
• non- acidfast
• non-spore forming bacillus .
•On subculture, rough colonies containing
filamentous forms are produced.
6. ANTIGEN AND TOXINS
• 1. Capsule: E. rhusiopathiae has a polysaccharide capsule which protects the
organism from phagocytosis.
• 2. Cell wall: The lipoteichoic acids and peptidoglycans of the gram-positive cell wall
interact with macrophages resulting in release of proinflammatory cytokines.
• 3. Neuraminidase: Contributes to virulence of E. rhusiopathiae by cleavage of sialic
acid residues on endothelial cells leading to thrombus formation. Neuraminidase is
also an adhesin helping adherence of the bacterium to cell surfaces.
• 4. Hyaluronic acid and coagulase: Role of these enzymes in virulence has not been
established.
7. GROWTH AND CULTURAL CHARACTERISTICS
• Erysipelothrix rhusiopathiae is a facultative anaerobe preferring an
environment containing 5%-10% CO2. Optimal growth occurs at 30C to 37C
and at a pH of 7.2 to 7.6.
• Growth occurs on nutrient agar and is improved by the addition of serum
or blood. Two kinds of colonies are seen.
• Smooth colonies are small and round; rough colonies are larger with
irregular borders.
• Rough colonies are obtained more frequently from chronic infections such
as endocarditis or arthritis.
• smooth colonies are obtained from acute forms of illness such as sepsis.
Colonies are nonhaemolytic and pinpoint after 24 hours. Α haemolysis is
observed (greenish) just around the colonies after 48 hours.
8. •E. rhusiopathiae is coagulase positive, catalase
negative and oxidase negative.
• It usually ferments lactose, glucose, levulose and
dextrin. But the acid production is poor.
•E. rhusiopathiae does not hydrolyse esculin or urea,
reduce nitrates or produce indole. Methyl red and
Voges Proskauer tests are also negative.
BIOCHEMICAL CHARACTERISTICS
9. • Erysipelothrix rhusiopathiae occurs in over 50 species of mammals and 30
species of wild birds.
• Virulent strains produce high levels of neuraminidase which cause vascular
damage and thrombus formation, and also helps in bacterial attachment and
invasion in to cells.
• Valvular endocarditis due to bacterial emboli and vascular inflammation,
results in chronic changes and damage to heart valves.
PATHOGENESIS
10. 1. Specimens are collected from affected sites.
2. Blood cultures are used to confirm septicaemia.
3. Gram staining of specimens.
4. Isolation in blood agar and biochemical identification.
5. PCR assays have been described.
6. Serological diagnosis is not practiced.
DIAGNOSIS
11. 1. Penicillin for 5 days is effective against acute forms of swine erysipelas.
Tetracyclines
treatment of chronic forms is less successful.
.
2 Vaccination using bacterins has been done.
TREATMENT
