Lecture 13: Actinomyces, Nocardia, Dermatophilus and Corynebacterium Flashcards
are actinobacteria gram negative or positive
Positive
What are the different lifestyles of actinobacteria
- Free living saprophytes (in soil)
- Mutualists
- Commensals
- Pathogens
What is the cell morphology of actinomyces
Typically rods or filaments, often branching
Actinomyces are ___ or ___ anaerobes
Facultative or obligate
T or F: actinomyces are capnophilic
True
identify species
Actinomyces spp
What is the primary habitat for actinomyces in mammals
Oral mucosa and tooth surfaces, MM of nasopharynx, urogenital tract, and intestinal tract
What is the cause of actinomyces
Traumatic inoculation of resident bacteria into susceptible tissues
Actinomyces is typically a ___infection
Polymicrobial
Pathogenicity of actinomyces ___with mixed infections
Increases
What is the pathogens is of actinomyces
Pyogranulomatous reactions, suppurative inflammation surrounded by granulomatous elements, fistulous tracts secrete purulent exudate- which contains sulfur granules made up of club colonies
Sulfur granules are useful in dx which organism
Actinomyces spp
what are these and what organism spp is likely
Sulfur granules, actinomyces spp
What does Actinomyces Bovis cause in cattle
Lumpy jaw, suppurative lesions of soft tissue and bone, abscesses
Osteomyeltitis—> tooth dislodgment, inability to chew, mandibular fractures
Cow presents with tooth dislodgement, inability to chew, and mandibular fractures, and lumpy jaw. What is likely bacterial cause
Actinomyces Bo is
What does Actinomyces suis cause in swine
Mastitis (lumpy udder) and ventral SQ lesions in sows
What causes A. Suis in sows
Traumatic inoculation during suckling and weaning
what is likely cause
Actinomyces bovis
What is likely cause
A. Suis
What does A. Bovis cause in horses
Mandibular lymphadenopathy (mimics strangles), fistulous withers and poll evil, skin nodules
What actinomyces species typically effects dogs and cats
A. Viscous
What does A. Viscous cause in dogs and cats
SQ abscesses, thoracic infections (pyothorax, pneumonia), abdominal and retroperitoneal infections
what is likely cause
A. Viscous
How do you dx actinomycis
- Clinical presentation
- Lumpy jaw- rads
- Exudates/ aspirates containing sulfur granules, club colonies
- PCR
- MALDI-TOF
What are these and what species does this indicate
sulfur granules, club colonies—> Actinomyces
What is tx for actinomycosis
- Surgery- drainage, excision and debridement of lesions
- Prolonged antibiotics- penicillin
- Bovine lumpy jaw- sodium iodide IV with antibiotics, debridement of bone lesion
What is the appropriate treatment of lumpy jaw from A. Bovis
Sodium iodide IV with antibiotics
Debridement of bone lesion followed by lavage with iodine solution
How can you prevent actinomycosis
- Good oral care
- Limit amount of rough forage fed
- Protect pets from grass awns
Dermatophilus congolensis is a ___anaerobe
Facultative
T of F: dermatophilus congolensis is capnophilic
True
Dermatophilus is a ___ parasite commonly found in cattle, sheep and horses
Obligate
How is dermatophilus congolensis transmitted
Direct contact, fomites, biting arthropods
What is the main reservoir for Dermatophilus congolensis
Asymptomatic chronically infected hosts
What is the pathogens is of D. Congolensis
- Trauma/ persistent wetting facilitates invasion of epidermis and hair follicles
- Virulence factors: enzymes (keratinases) increase epidermal permeability
- Infected epidermis and neutrophil exudate—> scab and crusting skin lesion