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| *Colonise mucous membranes | | *Colonise mucous membranes |
| | | |
− | *''Arcanobacterium pyogenes''
| + | |
− | **Characteristics:
| + | ===''Arcanobacterium pyogenes''=== |
− | ***Formerly known as ''Actinomyces pyogenes'' and ''Corynebacterium pyogenes''
| + | *Characteristics: |
− | ***Small facultatively anaerobic rod
| + | **Formerly known as ''Actinomyces pyogenes'' and ''Corynebacterium pyogenes'' |
− | ***Grows slowly on blood agar to produce small, white colonies surrounded by a zone of beta-haemolysis after 48 hours
| + | **Small facultatively anaerobic rod |
− | ***Produces hazy haemolysis after 24 hours; pin-point colonies after 48 hours
| + | **Grows slowly on blood agar to produce small, white colonies surrounded by a zone of beta-haemolysis after 48 hours |
− | ***Coryneform morphology, like Chinese characters; may be curved with slightly swollen ends
| + | **Produces hazy haemolysis after 24 hours; pin-point colonies after 48 hours |
− | ***Found in nasopharyngeal mucosa and genital tract of cattle, sheep, pigs
| + | **Coryneform morphology, like Chinese characters; may be curved with slightly swollen ends |
− | **Pathogenicity''
| + | **Found in nasopharyngeal mucosa and genital tract of cattle, sheep, pigs |
− | ***Opportunistic infections following injury or viral/mycoplasma infection in ruminants and pigs
| + | *Pathogenicity'' |
− | ***Extracellular toxins including haemolysin, proteases, DNase and neurominidase
| + | **Opportunistic infections following injury or viral/mycoplasma infection in ruminants and pigs |
− | ***Haemolytic toxin, pyolysin, member of the thiol-activated cytolysins (pore-forming toxins); possibly cytotoxic to phagocytic cells; dermonecrotising activity
| + | **Extracellular toxins including haemolysin, proteases, DNase and neurominidase |
− | **Clinical infections:
| + | **Haemolytic toxin, pyolysin, member of the thiol-activated cytolysins (pore-forming toxins); possibly cytotoxic to phagocytic cells; dermonecrotising activity |
− | ***Suppurative infections
| + | *Clinical infections: |
− | ***Abscesses especially in liver
| + | **Suppurative infections |
− | ***Pyometra
| + | **Abscesses especially in liver |
− | ***Summer mastitis
| + | **Pyometra |
− | ***Ovine foot disease
| + | **Summer mastitis |
− | ***Umbilical infections
| + | **Ovine foot disease |
− | ***Pneumonia
| + | **Umbilical infections |
− |
| + | **Pneumonia |
− | *''Actinomyces''
| + | |
| + | |
| + | ===''Actinomyces''=== |
| *Usually long and filamentous branching Gram positive rods | | *Usually long and filamentous branching Gram positive rods |
| *Anaerobic or facultativlyy anaerobic and capnophilic | | *Anaerobic or facultativlyy anaerobic and capnophilic |
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| ***Two types of colonies: large and smooth colonies with V, Y and T configurations or small and rough colonies with short branching filaments | | ***Two types of colonies: large and smooth colonies with V, Y and T configurations or small and rough colonies with short branching filaments |
| | | |
− | *''Actinobaculum suis''
| + | ===''Actinobaculum suis''=== |
| **Found in preputial mucosa of boars | | **Found in preputial mucosa of boars |
| **Anaerobic | | **Anaerobic |
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| **3mm diameter colonies with shiny raised centre and dull edge | | **3mm diameter colonies with shiny raised centre and dull edge |
| | | |
− | ''Nocardia'' | + | ===''Nocardia''=== |
| | | |
| *Aerobic short branching rods | | *Aerobic short branching rods |
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| *Lesions difficult to treat due to resistance of organisms to many antimicrobials (e.g. penicillins) | | *Lesions difficult to treat due to resistance of organisms to many antimicrobials (e.g. penicillins) |
| | | |
− | ''Dermatophilus congolensis'' | + | ===''Dermatophilus congolensis''=== |
| *Aerobic | | *Aerobic |
| *Motile zoospores | | *Motile zoospores |
| *No growth on Sabouraud dextrose agar | | *No growth on Sabouraud dextrose agar |
| *Found in scabs and in foci on skin of carrier animals | | *Found in scabs and in foci on skin of carrier animals |