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Microbiology > Lecture 13: Actinomyces, Nocardia, Dermatophilus and Corynebacterium > Flashcards

Lecture 13: Actinomyces, Nocardia, Dermatophilus and Corynebacterium Flashcards

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1
Q

are actinobacteria gram negative or positive

A

Positive

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2
Q

What are the different lifestyles of actinobacteria

A
  1. Free living saprophytes (in soil)
  2. Mutualists
  3. Commensals
  4. Pathogens
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3
Q

What is the cell morphology of actinomyces

A

Typically rods or filaments, often branching

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4
Q

Actinomyces are ___ or ___ anaerobes

A

Facultative or obligate

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5
Q

T or F: actinomyces are capnophilic

A

True

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6
Q

identify species

A

Actinomyces spp

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7
Q

What is the primary habitat for actinomyces in mammals

A

Oral mucosa and tooth surfaces, MM of nasopharynx, urogenital tract, and intestinal tract

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8
Q

What is the cause of actinomyces

A

Traumatic inoculation of resident bacteria into susceptible tissues

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9
Q

Actinomyces is typically a ___infection

A

Polymicrobial

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10
Q

Pathogenicity of actinomyces ___with mixed infections

A

Increases

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11
Q

What is the pathogens is of actinomyces

A

Pyogranulomatous reactions, suppurative inflammation surrounded by granulomatous elements, fistulous tracts secrete purulent exudate- which contains sulfur granules made up of club colonies

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12
Q

Sulfur granules are useful in dx which organism

A

Actinomyces spp

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13
Q

what are these and what organism spp is likely

A

Sulfur granules, actinomyces spp

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14
Q

What does Actinomyces Bovis cause in cattle

A

Lumpy jaw, suppurative lesions of soft tissue and bone, abscesses

Osteomyeltitis—> tooth dislodgment, inability to chew, mandibular fractures

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15
Q

Cow presents with tooth dislodgement, inability to chew, and mandibular fractures, and lumpy jaw. What is likely bacterial cause

A

Actinomyces Bo is

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16
Q

What does Actinomyces suis cause in swine

A

Mastitis (lumpy udder) and ventral SQ lesions in sows

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17
Q

What causes A. Suis in sows

A

Traumatic inoculation during suckling and weaning

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18
Q

what is likely cause

A

Actinomyces bovis

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19
Q

What is likely cause

A

A. Suis

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20
Q

What does A. Bovis cause in horses

A

Mandibular lymphadenopathy (mimics strangles), fistulous withers and poll evil, skin nodules

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21
Q

What actinomyces species typically effects dogs and cats

A

A. Viscous

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22
Q

What does A. Viscous cause in dogs and cats

A

SQ abscesses, thoracic infections (pyothorax, pneumonia), abdominal and retroperitoneal infections

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23
Q

what is likely cause

A

A. Viscous

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24
Q

How do you dx actinomycis

A
  1. Clinical presentation
  2. Lumpy jaw- rads
  3. Exudates/ aspirates containing sulfur granules, club colonies
  4. PCR
  5. MALDI-TOF
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25
What are these and what species does this indicate
sulfur granules, club colonies—> Actinomyces
26
What is tx for actinomycosis
1. Surgery- drainage, excision and debridement of lesions 2. Prolonged antibiotics- penicillin 3. Bovine lumpy jaw- sodium iodide IV with antibiotics, debridement of bone lesion
27
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
28
How can you prevent actinomycosis
1. Good oral care 2. Limit amount of rough forage fed 3. Protect pets from grass awns
29
Dermatophilus congolensis is a ___anaerobe
Facultative
30
T of F: dermatophilus congolensis is capnophilic
True
31
Dermatophilus is a ___ parasite commonly found in cattle, sheep and horses
Obligate
32
How is dermatophilus congolensis transmitted
Direct contact, fomites, biting arthropods
33
What is the main reservoir for Dermatophilus congolensis
Asymptomatic chronically infected hosts
34
What is the pathogens is of D. Congolensis
1. Trauma/ persistent wetting facilitates invasion of epidermis and hair follicles 2. Virulence factors: enzymes (keratinases) increase epidermal permeability 3. Infected epidermis and neutrophil exudate—> scab and crusting skin lesion
35
What is dermatophilosis
Exudative dermatitis with formation of scabs/crusts
36
The following was removed from dairy cow and histo performed what is cause
Dermatophilus congolensis Histo: alternating bands of keratinized epidermal cells and inflammatory cells
37
What are the predisposing factors for dermatophilosis
1. Prolonged wetting from rain—> lesions on dorsum and head 2. Trauma from thorny scrub—> lesions on face and legs 3. Arthropod bites
38
What is the lesion progression for dermatophilosis
Papules—> exudate—> paintbrush lesions of matted hair—> lesions form scab
39
Cow spent long time in rain and developed these lesions, what is likely cause
Dermatophilus congolensis
40
What bacteria could have caused this scab to form on horse
D. Congolensis
41
What are the treatment options for mild cases of Dermatophilosis
Grooming and isolation in dry quarters
42
What are the treatment options for severe causes of dermatophilosis
Antibiotics- penicillin-streptomycin
43
What is a treatment option for horses following dermatophilosis
Topical treatment with povidone iodine following grooming
44
What hemolysis is seen with dermatophilus congolensis
Beta-hemolysis
45
What spp have branching filaments that fragment into rods and cocci and are partially acid fast
Nocardia spp
46
Nocardia spp are ___aerobes
Obligate
47
Nocardia spp are ___ so widespread in soil and water
Saprophytes
48
What are the routes of infection for Nocardia spp
Trauma to skin, inoculation of teat canal, inhalation, ingestion
49
What is Nocardiosis characterized by
Suppurating lesions with various granulomatous features, sanguinopurulent exudates
50
What is the pathogens is of Nocardia
Suppurating lesions with sanguinopurulent exudates, lymph nodes may be involved, hematogenous spread
51
what spp is this
Nocardia spp
52
Pathogenic Nocardia are facultative ___organisms so they grow and survive inside ___
Intracellular, phagocytes
53
What virulence factors protect Nocardia against being killed by phagocytes
Superoxide dismutase and catalase
54
What species is this
Nocardia (growing inside macrophage)
55
What does nocardiosis cause in dairy cattle
Mastitis Can cause pneumonia, abortion (rare)
56
What does nocardiosis cause in swine
Pneumonia, abortion, lymphadentitis (rare)
57
What does nocardiosis cause in horses
Pneumonia, pleuritis, systemic abscesses, cutaneous-subcutaneous lesions, abortion (rare)
58
What does nocardiosis cause in cats and dogs
Utaenous and SQ lesions (often with abscesses), regional lymphadentitis, pulmonary nocardiosis with cough, hemoptysis, respiratory distress, mucopurulent oculonasal discharge
59
What is likely cause
Nocardiosis
60
How can you dx nocardiosis
1. Gram positive, partially acid fast bacilli 2. Culture and ID
61
Why do you do both a gram stain and acid fast when identifying nocardiosis
Differentiate between actinomyces
62
what species is this
Nocardia
63
What is tx for nocardiosis
1. Debridement and drainage of lesions 2. Prolonged trimethoprim-sulfonamides
64
What shape are corynebacterium
Pleomorphic
65
Corynebacterium are ___anaerobes and aerobes
Facultative
66
Where are corynebacteria found
Skin and mucous membranes (commensals)
67
How does corynebacterium pseudotuberculosis colonize
Via skin trauma
68
What is pathogens is of C. Pseudotuberculosis
1. Facultative intracellular pathogen (survives in phagocytes) 2. Spreads to draining LN 3. Virulence factors phospholipase D, cell wall lipids enhance invasion 4. Abscess form in LN
69
T or F: corynebacterium pseudotuberculosis can be a chronic infection that can persist for hosts life
True
70
What does C. Pseudotuberculosis cause in sheep and goats
Caseous lymphadentitis
71
What is the external form of C. Pseudotuberculosis
Abscess form in superficial LN, skin, subcutis
72
What is the internal form of C. Pseudotuberculosis
Abscess form in internal organs and LN
73
The external form of C. Pseudotuberculosis is more common in goats or sheep? And where are abscess
Goats- abscesses in head/neck regions
74
The internal form of C. Pseudotuberculosis is more common in goats or sheep? And what is it associated with
Sheep, associated with weight loss, and ill thrift (thin ewe syndrome)
75
What does the external form of C. Pseudotuberculosis cause in horses
Abscesses in pectoral region or along ventral midline of abdomen
76
goat presents with these abscesses. What is likely cause
C. Pseudotuberculosis external form
77
Sheep has these abscesses in liver, what is likely cause
C. Pseudotuberculosis, internal form
78
What are the vectors for external form of C. Pseudotuberculosis in horses
Horn fly, stable fly
79
What does the internal form of C. Pseudotuberculosis cause in horses
Abscess in liver, kidney, spleen and lungs, weight loss, fever, depression colic
80
Which form of C. Pseudotuberculosis in horses has a high case fatality rate (30-40%)
Internal form
81
Horse presents with severe limb swelling and cellulitis with multiple draining ulcerative lesions along lymphatics, in both hind limbs. What is this and what is cause
C. Pseudotuberculosis causing ulcerative lymphangitis
82
Horse presents with pectoral abscess with exudates, what is likely cause
C. Pseudotuberculosis, external form
83
How can you diagnose C. Pseudotuberculosis
1. Abscess contents 2. culture and ID 3. Internal form: rads and ultrasound, serological tests to detect antibodies against PLD and cell wall antigens
84
How can you diagnose internal C. Pseudotuberculosis
Radiographs, ultrasounds, serological tests to detect antibodies against PLD and cell wall antigens
85
What is tx for Caseous lymphadentitis caused by C. Pseudotuberculosis in sheep and goats
Abscess is thick walled so refractory antimicrobial therapy: 1. Long term (4-6wks) systemic antibiotics (penicillin G + rifampin) 2. Intralesional tulathromycin
86
What is the treatment for horses with lymphangitis and internal abscesses due to C. Pseudotuberculosis
Long-term IV antibiotics—> penicillin G and cephalosporins

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