Difference between revisions of "Rhodococcus equi"
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*Causes [[Peritoneal cavity - inflammatory#Peritonitis|peritonitis]] | *Causes [[Peritoneal cavity - inflammatory#Peritonitis|peritonitis]] | ||
*[[Bacterial infections#Rhodococcus equi|Pneumonia]] in foals | *[[Bacterial infections#Rhodococcus equi|Pneumonia]] in foals | ||
| + | |||
| + | ===Overview=== | ||
| + | |||
| + | *Gram-positive aerobic saprophyte found worldwide | ||
| + | *Found in soil and intestinal tract of animals | ||
| + | *Replicates at warm temperatures in soils contaminated by faeces of herbivores | ||
| + | *Opportunistic respiratory pathogen of foals under 6 months causing suppurative bronchopneumonia | ||
| + | |||
| + | |||
| + | ===Characteristics=== | ||
| + | |||
| + | *Grows on non-enriched media | ||
| + | *Salmon-pink mucoid colonies due to capsule and pigment production | ||
| + | *No haemolysis on blood agar | ||
| + | *Aerobic, non-motile | ||
| + | *CAMP test-positive | ||
| + | *Catalase positive, oxidase negative, weakly acid-fast | ||
| + | *Found as cocci and rods | ||
| + | *Intracellular pathogen | ||
| + | |||
| + | |||
| + | ===Pathogenesis and pathogenicity=== | ||
| + | |||
| + | *Organism present in faeces or healthy foals as well as adult horses | ||
| + | *Pastures can become heavily contaminated, leading to outbreaks | ||
| + | *Transmission via inhalation of dust contaminated with ''R. equi'' | ||
| + | *Virulence associated with specific surface antigens encoded by a large plasmid | ||
| + | *Capsular polysaccharide and mycolic acids in cell wall prevent phagocytosis | ||
| + | |||
| + | |||
| + | ===Clinical infections=== | ||
| + | |||
| + | *Bronchopneumonia and lung abscessation in foals less than 4 months | ||
| + | *Acute disease in 1 month-old foals: acute fever, anorexia, bronchopneumonia | ||
| + | *Insidious disease in 2-4 month-old foals with coughing, dyspnoea, weight loss, exercise intolerance, loud, moist rales on lung auscultation | ||
| + | *Occasionally diarrhoea | ||
| + | *Granulomatous ulcerative enterocolitis and mesenteric lymphadenitis in some foals following ingestion of contaminated sputum | ||
| + | *Foals over 6 months refractory to pulmonary infection | ||
| + | *Superficial abscesses in horses over 6 months | ||
| + | *Occasional infections in pigs and cattle, causing cervical lymphadenopathy | ||
| + | *Subcutaneous abscesses and mediastinal granulomas in cats | ||
| + | *Pneumonia in HIV patients | ||
| + | |||
| + | |||
| + | ===Diagnosis=== | ||
| + | |||
| + | *History of disease on the farm, age of foals affected and clinical signs | ||
| + | *Auscultation and rediography of thorax confirms pulmonary disease | ||
| + | * | ||
Revision as of 11:53, 20 July 2008
- Causes peritonitis
- Pneumonia in foals
Overview
- Gram-positive aerobic saprophyte found worldwide
- Found in soil and intestinal tract of animals
- Replicates at warm temperatures in soils contaminated by faeces of herbivores
- Opportunistic respiratory pathogen of foals under 6 months causing suppurative bronchopneumonia
Characteristics
- Grows on non-enriched media
- Salmon-pink mucoid colonies due to capsule and pigment production
- No haemolysis on blood agar
- Aerobic, non-motile
- CAMP test-positive
- Catalase positive, oxidase negative, weakly acid-fast
- Found as cocci and rods
- Intracellular pathogen
Pathogenesis and pathogenicity
- Organism present in faeces or healthy foals as well as adult horses
- Pastures can become heavily contaminated, leading to outbreaks
- Transmission via inhalation of dust contaminated with R. equi
- Virulence associated with specific surface antigens encoded by a large plasmid
- Capsular polysaccharide and mycolic acids in cell wall prevent phagocytosis
Clinical infections
- Bronchopneumonia and lung abscessation in foals less than 4 months
- Acute disease in 1 month-old foals: acute fever, anorexia, bronchopneumonia
- Insidious disease in 2-4 month-old foals with coughing, dyspnoea, weight loss, exercise intolerance, loud, moist rales on lung auscultation
- Occasionally diarrhoea
- Granulomatous ulcerative enterocolitis and mesenteric lymphadenitis in some foals following ingestion of contaminated sputum
- Foals over 6 months refractory to pulmonary infection
- Superficial abscesses in horses over 6 months
- Occasional infections in pigs and cattle, causing cervical lymphadenopathy
- Subcutaneous abscesses and mediastinal granulomas in cats
- Pneumonia in HIV patients
Diagnosis
- History of disease on the farm, age of foals affected and clinical signs
- Auscultation and rediography of thorax confirms pulmonary disease