Lecture 11 - Actinobacteria I Flashcards by Raegan Chambers

What are the four types of actinobacteria we must know?

Actinomyces
Nocardia
Dermatophilus
Corynebacterium

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Are Actinobacteria gram positive or negative?

Postive

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What is the cell morphology or actinobacteria?

Coccoid to filamentous

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What is the cell morphology of actinomyces?

Typically rods or filaments w/ branching

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What is the oxygen preference of actinomyces?

Facultative or obligate anaerobes

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What is needed to grow actinomyces?

Enriched media, plus many are capnophiles

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What is the lifestyle type of actinomyces?

Commensals

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What is the primary habitat of actinomyces?

oral mucosa + tooth surface

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Where else can actinomyces be found?

Nasopharynx + Urogenital tract + Intestinal tract

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What is the characteristics of an actinomyces infection?

Endogenous + Noncommunicable + Polymicrobial

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What is the typical cause of an actinomyces infection?

Traumatic inoculation

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Why do actinomyces infections tend to be polymicrobial?

Other bacteria decrease the amount of oxygen in the area, allowing a more suitable environment

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What type of reactions tend to occur with actinomyces?

Pyogranulomatous

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What are pyogranulomatous reactions?

Supprative inflammation surrounded by granulomatous elements

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What does the exudate of actinomyces tend to contain?

Sulfur granules,

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What are the virulence factors of actinomyces?

unknown

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What are the four important actinomyces to us?

Bovis + Suis + Viscosus + Hordeovulneris

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What does A. Bovis cause?

Lumpy jaw in cattle

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What is lumpy jaw?

Indurated, suppurative lesions in soft tissue + bone

Along with osteomyelitis

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What does osteomyelitis in lumpy jaw cause?

Tooth dislodgement + Inability to chew _ Mandibular fractures

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What does A. suis cause?

Mastitis + occasional infection in lungs, spleen, kidneys etc

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What causes mastitis in A. Suis?

Trauma from suckling + weaning

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What actinomyces can cause infections in Equine?

A. bovis

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What does A. Bovis do to Equine?

Manibular lymphadenopathty
Fistous withers + poll evil
Skin nodules

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What are the two actinomyces that effect dogs and cats?

Viscosus + Hordeovulneris

What does A. Viscosus tend to do in dogs and cats?

Subcutaneous abscesses

What is the major cause of A. hordeovulneris infection in dogs and cats?

Fox tails

What does A. hordeovulneris cause?

same as A. vicosus along with abscesses on liver and spleen + septic arthritis

What is the treatment for actinomycosis infections?

Surgery of lesions | Prolonged administration of AB's

What is done specifically for treatment of bovine lumpy jaw?

Sodium iodide concurrent w/ antibiotics

What are the general characteristics of dermatophilus congolensis?

branching filaments | Motile, coccoid zoospores

What is the oxygen preference of dermatophilus congolensis?

Facultative anaerobe + Capnophilic

What are the most common hosts of dermatophiuls congolensis?

Horse + Sheep + Cattle

How does transmission of dermatophilus congolensis occur?

Direct contact + Fomites + Biting arthopods

What is the main reservoir for dermatophilus congolensis?

Asymptomatic chronically infected hosts

What is the key feature of a stain of dermatophilus congolensis?

Railroad tracts

What symptoms are seen with dermatophilosis?

Exudative dermatitis with formation of scabs and crusts

What are the virulence factors in dermatophilosis?

Enzymes that increase permeability of epidermis

What are the common characteristics of a scab caused by dermatophilosis?

Painless + Nonpuritic + Easily removed

What age is it more common to see extensive lesions caused by dermatophilosis?

Young animals

What occurs with extensive lesions from dermatophilosis?

Secondary bacterial infections

What are the predisposing factors to getting dermatophilosis lesions?

Prolonged rain + Thorny shurbs + Arthropod bites

What is the location of dermatophilosis lesions when they are caused by wet weather?

Dorsum and head

What is the location of dermatophilosis lesions when they are caused by thorny shurbs?

Legs and Face

What is the lesion progression when caused by dermatophilosis?

Papules -- Exudate -- Paintbrush lesions

What treatment is recommended in mild dermatophilosis infections?

Grooming + isolation in dry quarters

What treatment is recommended in severe causes of dermatophilosis infections?

parenteral AB's

What is a specific recommendation for dermatophiolsis infections in horses?

Topical treatment

What are the basic characteristics of Nocardia?

Branching filaments that fragment into rods and cocci | partially acid-fast

What is the oxygen preference of Nocardia?

Obligate aerobes

What special structure do Nocardia have that allow them to be widespread in water and soil?

Sprophytes

What are the routes of infection for Nocardia?

Trauma to skin + Teat canal + Inhalation + Ingestion

Is Nocardia contagious?

What is seen with Nocardia infections?

Supprating lesions with variable granulomatous features LN often involved Hematogenous dissemination may occur

How does Nocardia survive in the body?

Survive + Grow in Phagocytes

What allows Nocardia to grow in phagocytes?

Virulence factors - superoxidase dismutase + catalase

What are the Nocardia disease patterns in ruminants?

Mastitis + Pneumonia + Abortion

What are the Nocardia disease patterns in swine?

Pneumonia + Abortion + Lymphadenitis

What are the Nocardia disease patterns in horses?

Pneumonia + Pleuritis + Systemic abscesses + Cutaneous-subcutaneous lesions + Abortion

What are the Nocardia disease patterns in cats?

Cutaneous-subcutaneous abscesses | Pulmonary + disseminated forms

What are the Nocardia disease patterns in dogs?

Pneumonia, pleuritis w/ empyma | Cutaneous-subcutaneous forms

What is the presumptive method of diagnosing Nocardia?

Staining and finding filamentous - Gram+ - partially acid fast bacteria

What is the definitive method for diagnosing Nocardia?

Antimicrobial susceptiability testing | PCR

What treatment methods are used in Nocardia?

Debridement + drainage of lesions | Prolonged adminstration of trimethoprim-sulfomide

What are the general characteristics of Corynebacterium?

Pleomorphic bacilli, non-spore forming

What are the shapes that Corynebacterium can be found in?

Coccoid + Rod + Club-shaped

What most commonly leads to infection of Corynebacterium?

Tissue trauma

What is the most common species of corynebacterium that is seen in animal infections?

pseudotuberculosis

What animal most commonly sees pseudotuberculosis infections?

Small ruminants

Where does C. pseudotuberculosis survive in the body?

Phagocytes

What are the steps in a C. pseudotuberculosis infection?

Multiplies at site + Spreads to draining lymph nodes

What are the virulence factors found in C. Pseudotuberculosis?

PLD + Cell wall lipids

What is commonly seen with a C. Pseudotuberculosis infection?

LN absecess

What is the most common presentation of C. pseudotuberculosis seen in sheep and goat?

Caseous lymphadenitis

What is the external form of CLA?

Abscesses on superficial LN + Skin + Subcutis

What is the internal form of CLA?

Abscesses on internal organs + LN

What animal is external form of CLA most common?

Goats

Where are abscesses most commonly seen in goats?

Head and neck

What animal is the internal form of CLA most common?

Sheep

What is seen with the internal form of CLA?

Weight loss + Ill thrift `

What are the three forms of C. pseudotuberculosis in equine?

External + Internal + Ulcerative lymphangitis

What is the external presentation of C. pseudoTB in horses?

Abscesses in pectoral region or along ventral midline of abdomen

What is the internal presentation of C. pseudoTB in horses?

Liver + Kidney + Spleen + Lungs | Weight loss + fever + depression + Colic

What does ulcerative lyphangitis due to C. pseudoTB look like in horses?

Severe limb swelling and cellulitis