- Cause peritonitis in horses
- A. pleuropneumoniae causes pneumonia in pigs
- Cause granulomatous inflammation.
- E.g. Actinobacillus lignieresii causes wooden tongue in cattle -> myositis
- A. equuli in arthritis of horses
Overview
Actinobacillus characteristics
- Small Gram negative coccobacilli
- Oxidase negative
- Do not grow on MacConkey
Actinobacillus lignieresii
- Commensal in the mouth of sheep and cattle
- Penetrates damaged mucosa to cause a granuloma, a condition known as Actinobacillosis
- Enodogenous, sporadic and chronic infection
- Lesions in the tongue, cheek, lips and sometimes in the lower gut and lungs from aspiration
- Often spreads from the site of infection to lymphatics
- Formation of fibrous tissue in the lesions lead to hardening of the tissue, hence the condition is known as 'wooden tongue' in cattle
- In sheep abscesses with thick walls are produced
- Feeding is impaired, causing loss of condition
- Recovery with antibiotics
Actinobacillus equuli
- Commensal of the equine intestinal mucosa
- Infection at birth causes severe enteritis and septicaemia within 24 hours, known as sleepy foal disease
- In foals that survive neonatal infection the condition progresses to cause joint infections and purulent nephritis
- RTX group cytotoxin present