Actinomyces, Nocardia, Dermatophilus, Corynebacterium

Question 1

what are actinobacteria?

Answer 1

highly diverse group of G+ bacteria
cell morphology - coccoid to filamentous

Question 2

what is the morphology of Actinomyces spp.?

Answer 2

rods or filaments

Question 3

Are Actinomyces commensal or opportunistic bacteria?

Answer 3

opportunistic

Question 4

what is Actinomycosis?

Answer 4

polymicrobial infection
Actinomyces is increased in mixed infections

Question 5

what type of reactions are common in actinomycosis?

Answer 5

pyogranulomatous reactions

Question 6

what does pyogranulomatous reactions contain?

Answer 6

suppurative inflammation
fistulous tracts secrete purulent exudate containing sulfur granules

Question 7

What is seen with Actinomyces bovis and with what species?

Answer 7

lumpy jaw - seen in cattle
mandibular lymphadenopathy - horses

Question 8

what is lumpy jaw?

Answer 8

indurated, suppurative lesions in soft tissue and bone
Osteomyelitis > tooth dislodgment, inability to chew, mandibular fractures

Question 9

what is the causative agent?

Answer 9

Actinomyces bovis

Question 10

What is seen with Actinomyces suis and with what species?

Answer 10

mastitis (lumpy udder)
swine

Question 11

what is the causative agent?

Answer 11

Actinomyces suis

Question 12

what causative agent often mimics strangles in horses?

Answer 12

Actinomyces bovis

Question 13

what does Actinomyces viscosus cause and in what species?

Answer 13

subcutaneous abscesses
dogs and cats

Question 14

what is the causative agent?

Answer 14

Actinomyces viscosus

Question 15

what does the exudate from Actinomycosis contain?

Answer 15

sulfur granlues

Question 16

what is this - collected from Actinomycosis exudate?

Answer 16

sulfur granules
club colonies with bacterial sized filaments

Question 17

How is Actinomycosis diagnosed?

Answer 17

gram stain, culture and species ID, PCR, MALDI-TOF mass spec

Question 18

With the Actinomyces species what should be cultured for the best chance of isolating pure cultures?

Answer 18

sulfur granules

Question 19

How is Actinomycosis treated?

Answer 19

surgery (debridement), prolonged admin of antibiotics

Question 20

How is bovine lumpy jaw treated?

Answer 20

sodium iodine IV with antibiotics, debridement of bone lesions w/ lavage of iodine solution

Question 21

How do you prevent Actinomycosis?

Answer 21

good oral care, limit amount of rough forage fed, protect pets from grass awns

Question 22

Is Dermatophilus congolensis commensal, opportunistic, or parasitic?

Answer 22

obligate parasite - grows on host

Question 23

Can zoonotic transmission occur in Dermatophilus congolensis?

Answer 23

yes

Question 24

How is Dermatophilus congolensis transmitted?

Answer 24

direct contact, fomites, and biting arthropods

Question 25

How does Dermatophilosis present?

Answer 25

exudative dermatitis with formation of scabs/crusts

Question 26

what is this lesion most likely caused by?

Answer 26

Dermatophilus congolensis

Question 27

Has this wound from Dermatophilosis early or late in formation?

Answer 27

early paintbrush lesions of matted hair is before the formation of scab/crust

Question 28

How does rain relate to Dermatophilosis?

Answer 28

trauma/persistent wetting facilitate invasion of epidermis and hair follicles prolonged wetting from rain > lesions on dorsum and head

Question 29

How is Dermatophilosis diagnosed?

Answer 29

clinical findings, history, isolation/ID via culture

Question 30

What are the treatments for mild, severe, and horse infections of Dermatophilosis?

Answer 30

mild - grooming and isolation in dry quarters servere- parenteral antibiotics horses - groom then topical treatment

Question 31

How is Dermatophilosis controlled/prevented?

Answer 31

isolate/cull affected animals minimize skin trauma and exposure to rain and ectoparasites

Question 32

What is a diagnostic feature of Nocardia spp? (think lab)

Answer 32

Partially acid-fast

Question 33

What is a saprophyte?

Answer 33

bacteria is widespread in soil and water

Question 34

Is Nocardia a halophyte or saprophyte?

Answer 34

saprophyte - widespread in soil and water

Question 35

Are nocardia commensal or opportunistic bacteria?

Answer 35

opportunistic - causes opportunistic infections

Question 36

what is Nocardiosis characterized by?

Answer 36

suppurating lesions with variable granulomatous features (sanguinopurulent exudates)

Question 37

How do Nocardia bacteria interact with phagocytes?

Answer 37

survive and grow inside phagocytes - virulence factor

Question 38

What can Nocardiosis cause in ruminants?

Answer 38

mastitis

Question 39

Is Nocardia an environmental or contagious mastitis?

Answer 39

environmental

Question 40

How does Nocardiosis present in cats and dogs?

Answer 40

cutaneous and subcutaneous lesions

Question 41

How is Nocardiosis diagnosed?

Answer 41

ID - filamentous, gram positive, partially acid fast bacilli

Question 42

Why do gram staining and acid-fast when differentiating between Nocardioisis and Actinomycosis?

Answer 42

gram + - actinomycosis and nocardiosis acid fast - only nocardiosis

Question 43

what is something that should be done when treating nocardiosis?

Answer 43

antimicrobial susceptibility testing - various strain have various antibiotic resistance

Question 44

How is Nocardiosis treated?

Answer 44

debridement and drainage of cutaneous-subcutaneous lesions prolonged admin of trimethoprim-sulfonamides

Question 45

How is Nocardiosis prevented/controlled?

Answer 45

good animal husbandry - hygiene

Question 46

Are Corynebacterium opportunistic or commensal bacteria?

Answer 46

commensal

Question 47

what are virulence factors of Corynebacterium pseudotuberculosis that aids the bacteria have multiple entry sites and spread to draining lymph nodes?

Answer 47

phospholipase D (PLD), cell wall lipids

Question 48

Is Cornebacterium pseudotuberculosis an acute or chronic infection?

Answer 48

chronic - may persist for host entire life

Question 49

what is the causative agent?

Answer 49

Corynebacterium pseudotuberculosis

Question 50

What does C. pseudotuberculosis cause in sheep and goat?

Answer 50

Caseous lymphadenitis (CLA)

Question 51

Which bacteria are facultative intracellular pathogens?

Answer 51

survives/grows in phagocytes -corynebacterium pseudotuberculosis -Nocardia spp.

Question 52

what is the external and internal form of caseous lymphadenitis (CLA)?

Answer 52

external - abscessation of superficial lymph nodes, skin, and subcutis internal - abscess formation in internal organs and lymph nodes

Question 53

what form of CLA is each picture?

Answer 53

left - external right - internal

Question 54

Can an individual have both external and internal or only one?

Answer 54

external and internal can occur in the same individual

Question 55

What can be seen with equids with C. pseudotuberculosis that is not seen in goats/sheep?

Answer 55

ulcerative lymphangitis

Question 56

what is seen with ulcerative lymphangitis?

Answer 56

severe limb swelling and cellulitis with multiple draining lesions along the lymphatics

Question 57

what is C. pseudotuberculosis causing in this horse?

Answer 57

ulcerative lymphangitis

Question 58

How is C. pseudotuberculosis diagnosed?

Answer 58

clinical findings, culture, ultrasound (internal)

Question 59

How is C. pseudotuberculosis treated?

Answer 59

external abscesses lanced, drained, and lavaged with antiseptic

Question 60

How is CLA treated in sheep/goats and horses?

Answer 60

long term antibiotics

Question 61

How is C. pseudotuberculosis controlled/prevented?

Answer 61

enforce hygiene, wound care during shearing, ear tagging, and surgical procedures vaccinate reduce exposure to flies