Difference between revisions of "Arcanobacterium pyogenes"

Revision as of 16:32, 3 March 2011

Characteristics:
- Formerly known as Actinomyces pyogenes and Corynebacterium pyogenes
- Small facultatively anaerobic rod
- Grows slowly on blood agar to produce small, white colonies surrounded by a zone of beta-haemolysis after 48 hours
- Produces hazy haemolysis after 24 hours; pin-point colonies after 48 hours
- Coryneform morphology, like Chinese characters; may be curved with slightly swollen ends
- Found in nasopharyngeal mucosa and genital tract of cattle, sheep, pigs
Pathogenicity
- Opportunistic infections following injury or viral/mycoplasma infection in ruminants and pigs
- Extracellular toxins including haemolysin, proteases, DNase and neurominidase
- Haemolytic toxin, pyolysin, member of the thiol-activated cytolysins (pore-forming toxins); possibly cytotoxic to phagocytic cells; dermonecrotising activity
Clinical infections:
- Suppurative infections
- Abscesses especially in liver
- Lymphadenitis, osteomyelitis, peritonitis and neural abscessation
- Pyometra
- Endometritis
- Summer mastitis
- Ovine foot disease
- Arthritis of sheep post-dipping; arthritis in pigs and arthritis in cattle
- Umbilical infections
- Acute exudative pneumonia and contributes to Enzootic pneumonia of calves
- May cause myositis
- Unclassified Actinomyces species isolated from closed cases of Poll Evil and Fistulous Withers
Treatment:
- Penicillin or broad spectrum antibiotics

Formerly known as Actinomyces pyogenes and Corynebacterium pyogenes
Small facultatively anaerobic rod
Grows slowly on blood agar to produce small, white colonies surrounded by a zone of beta-haemolysis after 48 hours
Produces hazy haemolysis after 24 hours; pin-point colonies after 48 hours
Coryneform morphology, like Chinese characters; may be curved with slightly swollen ends
Found in nasopharyngeal mucosa and genital tract of cattle, sheep, pigs

Opportunistic infections following injury or viral/mycoplasma infection in ruminants and pigs
Extracellular toxins including haemolysin, proteases, DNase and neurominidase
Haemolytic toxin, pyolysin, member of the thiol-activated cytolysins (pore-forming toxins); possibly cytotoxic to phagocytic cells; dermonecrotising activity

- Cause purulent arthritis
- In one or more joints
- Commonly contaminate wounds

Infections at any age:
- Corynebacterium pyogenes
  - Suppurative arthrtis
  - Often due to pebetrating wound into or close to joints

@@ Line 18: / Line 18: @@
 **Summer mastitis
 **Ovine foot disease
-**[[Joints Inflammatory - Pathology#In Sheep|Arthritis]] of sheep post-dipping; [[Joints Inflammatory - Pathology#In Pigs|arthritis in pigs]] and [[Joints Inflammatory - Pathology#In Cattle|arthritis in cattle]]
+**[[Infectious Arthritis#In Sheep|Arthritis]] of sheep post-dipping; [[Infectious Arthritis#In Pigs|arthritis in pigs]] and [[Infectious Arthritis#In Cattle|arthritis in cattle]]
 **Umbilical infections
 **[[Respiratory Bacterial Infections - Pathology#Acute exudative pneumonia|Acute exudative pneumonia]] and contributes to [[Respiratory Bacterial Infections - Pathology#Enzootic pneumonia of calves|Enzootic pneumonia of calves]]
@@ Line 54: / Line 54: @@
 *Summer mastitis
 *Ovine foot disease
-*[[Joints Inflammatory - Pathology#In Sheep|Arthritis]] of sheep post-dipping; [[Joints Inflammatory - Pathology#In Pigs|arthritis in pigs]] and [[Joints Inflammatory - Pathology#In Cattle|arthritis in cattle]]
+*[[Infectious Arthritis#In Sheep|Arthritis]] of sheep post-dipping; [[Infectious Arthritis#In Pigs|arthritis in pigs]] and [[Infectious Arthritis#In Cattle|arthritis in cattle]]
 *Umbilical infections
 *[[Respiratory Bacterial Infections - Pathology#Acute exudative pneumonia|Acute exudative pneumonia]] and contributes to [[Respiratory Bacterial Infections - Pathology#Enzootic pneumonia of calves|Enzootic pneumonia of calves]]