Difference between revisions of "Actinobacillus species"
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| − | # | + | <big><center>[[Infectious agents and parasites|'''BACK TO INFECTIOUS AGENTS AND PARASITES''']]</center></big> |
| + | <big><center>[[Bacteria|'''BACK TO BACTERIA''']]</center></big> | ||
| + | |||
| + | * Cause [[Peritoneal cavity - inflammatory#In horses|peritonitis in horses]] | ||
| + | |||
| + | ===Overview=== | ||
| + | |||
| + | *Mainly pathogens of farm animals | ||
| + | *Commensals of mucosa of upper respiratory tract and oral cavity | ||
| + | *Cannot survive long in the environment, therefore carrier animals are important in their transmission | ||
| + | *Cause [[General Pathology - Chronic Inflammation#Granulomatous Inflammation|granulomatous inflammation]] | ||
| + | |||
| + | |||
| + | ===''Actinobacillus'' characteristics=== | ||
| + | |||
| + | *Small Gram negative coccobacilli | ||
| + | *Oxidase negative | ||
| + | *Do not grow on MacConkey | ||
| + | *Non-motile | ||
| + | *Facultative anaerobes which ferment carbohydrates to produce acid | ||
| + | |||
| + | |||
| + | ===''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 | ||
| + | *[[Muscles - inflammatory#Wooden tongue|myositis]] and 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 | ||
| + | *''A. equuli'' in [[Joints - inflammatory#In Horses|arthritis of horses]] | ||
| + | *RTX group cytotoxin present | ||
| + | |||
| + | |||
| + | ===''Actinobacillus suis''=== | ||
| + | |||
| + | *Fatal septicaemia in pigs 1-8 weeks old | ||
| + | *Causes abscesses in joints and lungs of older pigs | ||
| + | *Carried in the nasopharynx of pigs and nose of horses | ||
| + | *Carriage may confer immunity to the more severe pleuropneumonia | ||
| + | |||
| + | |||
| + | ===''Actinobacillus pleuropneumoniae''=== | ||
| + | |||
| + | *Contagious porcine pleuropneumonia | ||
| + | *Endemic in UK | ||
| + | *Most strains are NAD-dependent (grow on Heated Blood agar) | ||
| + | *Positive CAMP reaction | ||
| + | *12 serotypes causing the same disease | ||
| + | *Different serotypes in different regions, with serotypes 3,6 and 8 the most common in the UK | ||
| + | *Acute disease in susceptible herds with high morbidity and mortality | ||
| + | *Causes [[Bacterial infections#Actinobacillus pleuropneumoniae|pneumonia]] in pigs | ||
| + | *Carrier herds have some immunity, protecting from acute disease, where lesions are often subclinical, and deaths sporadic | ||
| + | *Lung scarring and pleural adhesions in many recovered animals | ||
| + | *Solid immunity develops in recovered animals to all serotypes | ||
| + | *The disease is spread between herds by carrier pigs | ||
| + | *The bacteria on the palatine tonsil are undetected by serologucal tests and swabbing, and can therefore cause an outbreak in naive pigs | ||
| + | *Killed and bacterin vaccines are available | ||
| + | *Produce one or two RTX group cytolytic toxins | ||
| + | *RTX toxins: | ||
| + | **'Repeat in ToXin' - named because there are several peptide repeats within the molecules | ||
| + | **Produced by various Gram-negative bacteria | ||
| + | **Possess four contiguous genes, A, B, C and D | ||
| + | **A is the structural gene; B and D are required for secretion; C allows post-translational activation of the gene product of A into a functional product | ||
| + | **ApxI is a strong haemolysin with cytolytic activity | ||
| + | **ApxII is a weak haemolysin | ||
| + | **ApxIII is a cytotoxin | ||
| + | **Different ''Actinobacillus pleuropneumonia'' serotypes secrete a particular combination of toxins; American serotypes secrete ApxI and II; European serotypes secrete ApxII and III | ||
Revision as of 13:17, 20 December 2007
- Cause peritonitis in horses
Overview
- Mainly pathogens of farm animals
- Commensals of mucosa of upper respiratory tract and oral cavity
- Cannot survive long in the environment, therefore carrier animals are important in their transmission
- Cause granulomatous inflammation
Actinobacillus characteristics
- Small Gram negative coccobacilli
- Oxidase negative
- Do not grow on MacConkey
- Non-motile
- Facultative anaerobes which ferment carbohydrates to produce acid
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
- myositis and 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
- A. equuli in arthritis of horses
- RTX group cytotoxin present
Actinobacillus suis
- Fatal septicaemia in pigs 1-8 weeks old
- Causes abscesses in joints and lungs of older pigs
- Carried in the nasopharynx of pigs and nose of horses
- Carriage may confer immunity to the more severe pleuropneumonia
Actinobacillus pleuropneumoniae
- Contagious porcine pleuropneumonia
- Endemic in UK
- Most strains are NAD-dependent (grow on Heated Blood agar)
- Positive CAMP reaction
- 12 serotypes causing the same disease
- Different serotypes in different regions, with serotypes 3,6 and 8 the most common in the UK
- Acute disease in susceptible herds with high morbidity and mortality
- Causes pneumonia in pigs
- Carrier herds have some immunity, protecting from acute disease, where lesions are often subclinical, and deaths sporadic
- Lung scarring and pleural adhesions in many recovered animals
- Solid immunity develops in recovered animals to all serotypes
- The disease is spread between herds by carrier pigs
- The bacteria on the palatine tonsil are undetected by serologucal tests and swabbing, and can therefore cause an outbreak in naive pigs
- Killed and bacterin vaccines are available
- Produce one or two RTX group cytolytic toxins
- RTX toxins:
- 'Repeat in ToXin' - named because there are several peptide repeats within the molecules
- Produced by various Gram-negative bacteria
- Possess four contiguous genes, A, B, C and D
- A is the structural gene; B and D are required for secretion; C allows post-translational activation of the gene product of A into a functional product
- ApxI is a strong haemolysin with cytolytic activity
- ApxII is a weak haemolysin
- ApxIII is a cytotoxin
- Different Actinobacillus pleuropneumonia serotypes secrete a particular combination of toxins; American serotypes secrete ApxI and II; European serotypes secrete ApxII and III