Difference between revisions of "Actinomycetes"
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***Found naturally in oral cavity of cattle | ***Found naturally in oral cavity of cattle | ||
***Prefers anaerobic conditions but not strict anaerobe | ***Prefers anaerobic conditions but not strict anaerobe | ||
− | *** | + | ***Entry of organism into tissues following trauma to the mucosa from rough feed or tooth eruption |
+ | ***Causes [[General Pathology - Chronic Inflammation#Granulomatous Inflammation|granulomatous inflammation]] of soft tissues and bone, causing [[Oral Cavity - Teeth#Mandibular Osteomyelitis|lumpy jaw]] | ||
***Usually invades mandible to cause [[Bones - inflammatory#Osteomyelitis|osteomyelitis]] and may extend to surrounding [[Muscles - inflammatory#Actinomycosis bovis|muscles]] | ***Usually invades mandible to cause [[Bones - inflammatory#Osteomyelitis|osteomyelitis]] and may extend to surrounding [[Muscles - inflammatory#Actinomycosis bovis|muscles]] | ||
+ | ***The lesions begins as a painless swelling of the affected bone | ||
+ | ***Swelling becomes more painful and enlarges over a number of weeks, gaining fistulous tracts which discharge pus | ||
***Organisms found in yellow sulphur granules | ***Organisms found in yellow sulphur granules | ||
***Club colony formation | ***Club colony formation | ||
***Colonies adhere to agar media and are non-haemoltic | ***Colonies adhere to agar media and are non-haemoltic | ||
+ | ***Surgical treatment possible when lesions are small | ||
+ | ***Prolonged parenteral penicillin treatment may be beneficial early in the disease | ||
**''Actinomyces viscosus'' | **''Actinomyces viscosus'' | ||
***Commensal of oral cavity of dogs and humans | ***Commensal of oral cavity of dogs and humans | ||
Line 90: | Line 95: | ||
===''Actinobaculum suis''=== | ===''Actinobaculum suis''=== | ||
− | **Found in preputial mucosa of boars | + | **Found in preputial mucosa of healthy boars |
**Anaerobic | **Anaerobic | ||
**Coryneform morphology | **Coryneform morphology | ||
**Produces urease | **Produces urease | ||
**3mm diameter colonies with shiny raised centre and dull edge | **3mm diameter colonies with shiny raised centre and dull edge | ||
+ | **Disease transmitted at coitus | ||
+ | **Sows develop disease within 3-4 weeks of mating | ||
**Produces lesions in urinary tract of sows | **Produces lesions in urinary tract of sows | ||
**Cystitis and pyelonephritis in sows | **Cystitis and pyelonephritis in sows | ||
+ | **Anoreixa, arching of back, dysuria and haematuria | ||
+ | **May be fatal | ||
Revision as of 16:08, 17 February 2008
- Cause peritonitis in dogs and peritonitis in cattle and peritonitis in pigs
- Micropolyspora faeni and Thermactinomyces vulgaris in Bovine Farmers Lung
- Thermactinomyces vulgaris may cause COPD
Overview
- Gram positive bacteria
- Grow slowly on media and produce branching filaments
- Opportunistic infections causing inflammatory responses and granulomatous reactions
- Animal pathogens include Actinomyces, Arcanobacterium, Actinobaculum, Nocardia and Dermatophilus
Arcanobacterium, Actinomyces and Actinobaculum species
- Non-motile, non-spore-forming bacteria
- Anaerobic or facultative anaerobes
- Grow on enriched media; non-acid fast
- Colonise mucous membranes
- Modified Ziehl-Neelson negative
Arcanobacterium pyogenes
- 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
- Umbilical infections
- Suppurative pneumonia
- Treatment:
- Penicillin or broad spectrum antibiotics
- Unclassified Actinomyces species isolated from closed cases of Poll Evil and Fistulous Withers
Actinomyces
- Usually long filamentous branching Gram positive rods
- Anaerobic or facultativlyy anaerobic and capnophilic
- Live in nasopharyngeal and oral mucosa
- Cause pyogranulomatous lesions
- Actinomyces bovis
- Found naturally in oral cavity of cattle
- Prefers anaerobic conditions but not strict anaerobe
- Entry of organism into tissues following trauma to the mucosa from rough feed or tooth eruption
- Causes granulomatous inflammation of soft tissues and bone, causing lumpy jaw
- Usually invades mandible to cause osteomyelitis and may extend to surrounding muscles
- The lesions begins as a painless swelling of the affected bone
- Swelling becomes more painful and enlarges over a number of weeks, gaining fistulous tracts which discharge pus
- Organisms found in yellow sulphur granules
- Club colony formation
- Colonies adhere to agar media and are non-haemoltic
- Surgical treatment possible when lesions are small
- Prolonged parenteral penicillin treatment may be beneficial early in the disease
- Actinomyces viscosus
- Commensal of oral cavity of dogs and humans
- Canine actinomycosis
- Causes localised subcutaneous pyogranulomatous lesions and fibrovascular proliferation of peritoneal and pleural surfaces in dogs
- Leads to pyothorax
- Respiratory distress
- Cutaneous pustules in horses
- Abortion in cattle
- Rods contained in soft grey granules which release the organism when squashed
- Two types of colonies: large and smooth colonies with V, Y and T configurations or small and rough colonies with short branching filaments
- Grow in 10% carbon dioxide
- Usually responds to penicillin
- Actinomyces hordeovulneris
- Organism found in seed heads of certain grasses
- Colonies adhere to agar and are non-haemolytic
- Filamentous, branching organisms
- Cause cutaneous and visceral abscessation, pleuritis, peritonitis and arthritis in dogs
- Actinomyces bovis
Actinobaculum suis
- Found in preputial mucosa of healthy boars
- Anaerobic
- Coryneform morphology
- Produces urease
- 3mm diameter colonies with shiny raised centre and dull edge
- Disease transmitted at coitus
- Sows develop disease within 3-4 weeks of mating
- Produces lesions in urinary tract of sows
- Cystitis and pyelonephritis in sows
- Anoreixa, arching of back, dysuria and haematuria
- May be fatal
Nocardia
- Aerobic short branching rods
- Non-motile
- Spores from aerial filaments
- Grow on Sabouraud dextrose agar
- Cell wall contains mycolic acids (hence slightly acid fast)
- Nocardia asteroides found in soil
- Causes granulomatous lesions in animals
- Involved in peritonitis and pleuritis in dogs
- Survives and multiplies in macrophages
- Lesions in thoracic cavity, skin and other tissues
- Chronic, progressive disease
- Lesions difficult to treat due to resistance of organisms to many antimicrobials (e.g. penicillins)
Dermatophilus congolensis
- Aerobic
- Motile zoospores
- No growth on Sabouraud dextrose agar
- Found in scabs and in foci on skin of carrier animals