Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Sarah - Equine > Chapter 4 - Bacteria > Flashcards

Chapter 4 - Bacteria Flashcards

1
Q

What is the most common metabolic cause of skin infection in horses?

A

Pituitary pars intermdia dysfunction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q 
Are the below antibiotics bacteriostatic or bactericidal?
TMPS
Macrolides
FQs
Gentamicin 
Tetracyclines
A 
TMPS - bactericidal
Macrolides - bacteriostatic
FQs - bactericidal 
Gentamicin - bactericidal 
Tetracyclines - bacteriostatic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Macrolides concentrate in phagocytic cells; true or false?

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Why should chloramphenicol not be given to animals in the food chain?

A

It causes a severe, idiosyncratic bone marrow dyscrasia in people

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Name two Staphylococcal superantigens that can trigger local cutaneous and immunological responses

A

Protein A

Enterotoxin C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Name two Strep equi equi virulence factors

A
  1. A hyaluronic acid capsule
  2. M(SeM) protein which inhibits phagocytosis and complement deposition and bactericidal mechanisms of neutrophils and macrophages (can test for antibody titres)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Corynebacterium spp. are gram-positive, pleomorpohic bacteria, true or false?

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Which virulence factor of Corynebacterium pseudotuberculosis can:
Hydrolyse lysophosphatidylcholine and sphingomyelin, degrading endothelium and increasing vascular permeability (oedema) AND inhibit neutrophil chemotaxis and degranulation of phagocytic cells.

A

Phospholipase D

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Which insect vector is through to be involved in the development of Corynebacterium pseudotuberculosis abscesse in horses?

A

Biting flies, especially horn flies (Haematobia irritans).

Stomoxys calcitrans, and Musca domestica also likely

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Does moisture or heat cause the release of infective, motile, flagellated zoospores form of D. congolensis?

A

Moisture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

D. congolensis possess an alkaline ceramidase gene; this catalyses the cleavage of ceramide to _____ and ______ in the epidermis.

A

Fatty acids and sphingosine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Why are white areas of skin affected with D. congolensis often associated with severe erythema?

A

They may represent a type of photodermatitis caused by D. congolensis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Name three differentials for dermatophilosis

A 
Dermatophytosis
Staph. folliculitis
Demodicosis
PF
Sterile eosinophilic folliculitides
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Which histopath stains can be used to visualise D. congolensis?

A

Giemsa
Brown and Brenn
Acid orcein-Giemsa
Can be seen with H&E

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

When active lesions are not present, avulsed thick crusts can be used to demonstrate D. congolensis organisms on histopath or culture?

A

Histopath

Culture in chronic, non-exudative stages can be overgrown by secondary invaders and saprophytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Do horses previously affected by dermatophilosis have lasting immunity to prevent reinfection?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Which special stains help demonstrate Actinomyces on histopathology?

A

Gram (+ve)

Grocott methenamine silver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Which systemic disease process should be considered in horses that develop bacterial pseudomycetoma?

A

Pituitary pars intermedia dysfunction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Most reported cases of clostridial infections in horses are associated with what?

A

IM injections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Which aerobic, gram-negative rod causes glanders?

A

Burkholderia mallei

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Is Burkholderia mallei a zoonotic agent?

A

Yes - infection is usually fatal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Which systemic sign accompanies nodular skin lesions in glanders?

A

Mucopurulent nasal discharge

In the chronic form, nasal and subcutaneous nodules develop, eventually ulcerating. Lymph vessels are enlarged and nodular abscesses form along their course and discharge yellow pus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the main cutaneous signs associated with purpura haemorrhagica?

A

S/C limb oedema

Haemorrhage on mucous membranes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Which Staph. most often causes folliculitis in horses?

A

S. aureus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Name three follicular causes of pustules/crust in horses

A

Staph. folliculitis
Demodicosis
Dermatophytosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Name three non-follicular causes of pustules/crust in horses

A

Dermatophilosis
Mites (e.g. Chorioptes)
Allergic skin disease (e.g. IBH, contact)
PF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

In the study by Kaiser‑Thom et al. (2022), were Staph. isolates higher in horses with pastern dermatitis compared to healthy controls?

A

Yes - from pastern (59.0 % vs. 6.3 % in unaffected horses; P<0.001), and nose (59.0 % vs. 8.4 %; P<0.001).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

In horses with pastern dermatitis, how did Staph. populations differ from pastern and nasal swabs?

A

Antimicrobial resistance genes were almost equally frequent in pastern and in nasal samples, whereas some virulence factors such as the beta‑hemolysin, ESAT‑6 secretion system, and some enterotoxins were more abundant in isolates from pastern samples, possibly enhancing their pathogenic potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Other than Staph. aureus, which other Staph. can be associated with pyoderma in horses?

A

Staphylococcus hyicus subsp. hyicus

Staphylococcus delphini

30
Q

Which antisepetic shampoos/sprays can be used to treat Staph. infection in horses?

A

Chlorhexidine
Benzyl peroxide
Iodophors (e.g., povidone-iodine)

31
Q

In the study by Van den Eede et al. (2012), what % of long-term hospitalised horses carried MRSP? Which body site was most frequently positive?

A

40%

Nostrils

32
Q

How was bacterial diversity affected in horses with equine pastern dermatitis (affected limb compared to non-affected limb)?

A

Bacterial alpha diversity was reduced in affected pasterns (P<0.001) and this reduction was significantly associated with the EPD forms (P<0.001), and not with the type of pretreatment (P>0.14)

33
Q

Name four differentials for Staphylococcal pastern folliculitis and furunculosis

A
  1. Other bacterial infection
  2. Dermatophilosis
  3. Spirochetes
  4. Dermatophytosis
  5. Chorioptic mange
  6. Trombiculiasis
  7. Pelodora
  8. Vaccinia
  9. Irritant contact dermatitis
  10. Allergic contact dermatitis
  11. Photosensitisation
  12. Trauma
  13. Vasculitis
  14. PF
  15. CPL
34
Q

Name two toxins produced by CoPS

A
  • Enterotoxins A, B, C, D (C = superantigen)
  • Protein A (= superantigen)
  • Haemolysins
  • Leukocidins
  • Dermonecrotoxins
35
Q

Which haematological finding was associated with the development of purpura haemorrhagica in horses with Strep equi subsp. equi infection?

A

Anaemia

36
Q

Are S. equi M protein (SeM) antibody titers elevated with complications?

A

No - SeM antibody titers can be increased after infection in the absence of complications of strangles

37
Q

Cutaneous and internal abscesses and ulcerative lymphangitis are clinical features of Corynebacterium pseudotuberculosis infection in horses. Most commonly, abscesses develop in the ________, ________, _________, and _______ areas. Local wound care should be an integral part of treatment.

A

Pectoral, axillary, ventral abdominal and inguinal areas

Severe cellulitis, panniculitis, and skin sloughing of the head region has also been described

38
Q

What treatment is indicated for Corynebacterium pseudotuberculosis infection in horses?

A

Drainage and systemic antibiotics are necessary to cure the lesions. The organism is typically sensitive to penicillin and oral sulfonamides

39
Q

Occasionally, C. pseudotuberculosis infection can progress causing lymphangitis. Name other organisms than can cause ulcerative lymphangitis

A 
Bacterial = Pseudomonas, Pasteurella and Actinomyces spp.
Fungal = Histoplasma
40
Q

True or false; Dermatophilus congolensisis a Gram-positive coccobacillary actinomycete that causes an exudative dermatitis in a variety of species, most notably in ruminants and horses, although rare infections occur in cats, dogs, and humans.

A

True

41
Q

Which molecular test can be performed on crusts in suspected cases of dermatophilus congolensisis if cytology is negative?

A

RT-qPCR

42
Q

What is the primary source of infection for dermatophilosis?

A

Chronically infected horses

43
Q

What are mechanical vectors of dermatophilosis?

A
  1. Biting and non-biting flies

2. Contaminated clippers

44
Q

The environment may be a source for recontamination with Dermatophilosis because the zoospores resist drying at 100ºC and can survive in dry scabs at 28–31ºC for ___ months

A

42

45
Q

What are the primary lesions of dermatophilosis in horses?

A

Follicular and non-follicular papules and pustules

46
Q

What are the four types of lesion distribution commonly seen with dermatophilosis in horses?

A
  1. Rump and topline (‘rain scald’)
  2. Saddle area (associated with tack)
  3. Face and neck (associated with tack)
  4. Pasterns, coronets and heels (‘grease heel’, ‘scratches’, ‘mud fever’ – associated with poorly drained/muddy pastures)
47
Q

Which stains can be used to identify Dermatophilosus congolensis on cytology?

A

Diff Quik, Gram, methylene blue

48
Q

How do you prepare a macerated crust slide for cytology?

A
  1. Place 1–2 drops of saline on a clean slide.
  2. Clip off excess hair from the crust sample and place crust into saline.
  3. Macerate/soften for 15 minutes then remove larger pieces.
  4. Crush remaining material on the slide and allow to air dry.
  5. Heat fix slide for a few seconds.
  6. Stain with Diff Quik or methylene blue and allow to dry.
49
Q

How do you treat dermatophilosis in the horse?

A
  1. Keep the animal dry (may spontaneously regress in 4 weeks)
  2. Remove and dispose of crusts (may require sedation as painful)
  3. Topical treatment e.g. lime sulfur, iodophors or chlorhexidine
  4. Systemic antibiotics e.g. penicillins, TMPS, erythromycin
  5. Improve hygiene and management practices
50
Q

What is in the circle in this image?

A

Dermatophilus congolensis

51
Q

True or false; It is important to burn or properly dispose of crusts to prevent spread of dermatophilosis to other animals.

A

True

52
Q

CoPS are isolated from what % of cases of equine cellulitis?

A

> 80%

53
Q

Which breed of horse are most commonly reported with cellulitis?

A

Thoroughbreds

54
Q

What are the clinical signs of ulcerative lymphangitis in the horse?

A
  • Hindlimb fetlock most common site, rarely above hock
  • Hard to fluctuant nodules/abscesses that ulcerate and develop draining tracts
  • Corded regional lymphatics
  • Oedema, cellulitis and fibrosis (particularly with C. pseudotuberculosis)
  • Lameness, fever, anorexia
55
Q

Rhodococcus equi rarely causes cutaneous abscesses, cellulitis and ulcerative lymphangitis in horses; what clinical signs are more common with this infection?

A

Pneumonia and lymphadenitis in foals

56
Q

True or false; in dermatophilosis, intracellular oedema and reticular degeneration of keratinocytes is a striking feature on histopathology

A

True

57
Q

Are most horses with Nocardia infection immunocompromised?

A

Yes

58
Q

Actinobacillus equi causes which diseases in horses?

A
  • ‘Shigellosis’ a fatal septicaemia in foals

- Bacterial pseudomycetoma

59
Q

Skin biopsy from a granulomatous skin lesion; what is the arrow pointing at?

A

Eosinophilic tissue grain

Splendore-Hoeppli

60
Q

What is the most commonly isolated bacteria from subcutaneous abscesses in the horse?

A

Corynebacterium pseudotuberculosis

61
Q

Name two differential diagnoses for bacterial pseudomycetoma in horses

A
  • Other bacterial and fungal granulomas
  • Foreign body granuloma
  • Habronemiasis
  • Granulation tissue
  • Neoplasia
62
Q

What are the clinical signs of clostridial infection in horses?

A
  • Warm, painful, pitting, deep swelling
  • Serosanguinous, foul-smelling draining fluid
  • Develops to cool, hypoesthetic, blue-purple skin
  • Necrosis and sloughing
  • Fever, depression, tachycardia
  • Toxaemia and death can occur within a week
  • Laminitis is a common complication
63
Q

How do you treat clostridial infection in horses?

A
  • IV potassium penicillin
  • Surgical wound management (disrupt anaerobic environment)
  • Analgesia (very painful!)
64
Q

Which are the most common anaerobes involved in cellulitis, abscesses and draining tracts in horses?

A

Clostridium spp.
Bacteroides spp.
Fusobacterium spp.

65
Q

Which special stain can be used to identify bacillus anthracis?

A

Gram

66
Q

How long can Burkholderia mallei (glanders) survive outside the body?

A

3-5 weeks

67
Q

What is the main differential diagnosis for Burkholderia mallei (glanders)?

A

Histoplasma farcinimosi (epizootic lymphangitis) - lymphangitis and respiratory disease

68
Q

What is the mallein test?

A

Mallein, a heat-extracted protein from B. mallei, is injected intradermally into the lower eyelid and measured 24-48 hours later

PCR an alternative

69
Q

Which strain of MRSA is commonly found in horses in Europe?

A

Clonal complex (CC)398

70
Q

In rural Germany, what % of non-hospitalised horses carried MRSA and ESBL E. coli?

A

MRSA - 0.9%

ESBL E. coli - 4%; associated with prior antibiotic treatment and veterinary examinations

Sarah - Equine (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions