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Flashcards in Bacterial skin diseases Deck (36)
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1
Q

Define pyoderma

A

= bacterial skin infection. Can be localised, widespread or generalised. Very common and important. Can be itchy or painful. Dog most commonly. Also cats, horses, small mammals, farm animals and birds.

2
Q

What are some triggering factors for bacteria skin disease? 5

A
  • breaks in physical skin barrier
  • loss of immune defences/immune imbalance
  • Skin disease (ALLERGIES, ectoparasites, cornification -defects, neoplasia, alopecia)
  • ENDOCRINOPATHIES
  • metabolic/nutritional problems
3
Q

What bacteria are involved in pyoderma? 6

A
  • S.pseudintermedius*
  • S.schleiferi subsp coagulans
  • S.aureus
  • S.hyicus (pigs)
  • Other gram positives (Strep)
  • Gram negatives - Coliforms, Pseudomonas spp., Proteus
4
Q

Dx - pyoderma - 4

A
  • Hx - recurrent, previous response to ABs
  • CS - papules, pustules, epidermal collarettes, draining sinuses
  • Cytology - tape strip, impression smear + gram stain and Diffquik
  • Bacteria - and sensitivity, swab, crust and tissue
5
Q

What are the 3 main types of pyoderma?

A

SURFACE - hot spot, intertrigo (skin folds), mucocutaneous, bacterial overgrowth
SUPERFICIAL - impetigo (puppies), folliculitis
DEEP - furunculosis, ache, bacterial granuloma

6
Q

Tx - surface pyoderma

A
  • long term therapy
  • surgical correction?
  • antibacterial shampoos/creams
7
Q

What is pyotraumatic dermatitis also known as?

A

= hot spot and acute moist dermatitis

8
Q

Describe pyotraumatic dermatitis

A

acute, painful, self-trauma –> bacterial invasion, disruption of the stratum corneum, often large breeds (Retriever), underlying pruritic problem (FAD, anal sac irritation, otitis)

9
Q

Tx - pyotraumatic dermatitis

A
  • topical ABs
  • anti-inflammatories (depends on severity)
  • treat/correct underlying causes
10
Q

What are satellite lesions?

A

lesions found around the main lesion. suggests haematogenous spread therefore deep pyoderma

11
Q

Which tx is contraindicated in deep pyoderma?

A

GCs

12
Q

Describe impetigo

A
  • pustules in interfollicular epidermis
  • young dogs
  • ventral abdomen
  • often responds to topical therapy alone
13
Q

What is canine superficial pyoderma?

A
  • Infection of the superficial portion of the hair follicle.
    >90% cases are S.pseudintermedius (>80% of these are endogenous strains)
  • often recurrent and pruritic
  • typically ventral abdomen and trunk
14
Q

What are the 4 commonest lesions in canine superficial pyoderma?

A

Papules, epidermal collarettes, alopecia and pruritus

Clinical presentation varies with coat length

15
Q

Outline lesion progression with time in canine superficial pyoderma

A

Macule -> papule –> pustule –> epidermal collarette –> alopecia and pruritus.
Clinical presentation varies with coat length

16
Q

What are the 3 main types of deep pyoderma?

A
  • furunculosis
  • acne
  • bacterial granuloma
17
Q

Pathogens - deep pyoderma

A
  • Staph (60-80%)
  • Gram negatives
  • Anaerobes
18
Q

Dx - deep pyoderma

A
  • Bacterial culture always indicated, may have to be from tissue (DON’T put skin biopsy in formalin)
  • Cytology, sin scrapes etc, blood tests, imaging for underlying causes.
19
Q

Tx - deep pyoderma

A
  • based on cytology while waiting for culture results

- based on susceptibility testing thereafter

20
Q

What are the underlying causes for deep pyoderma?

A
  • As for superficial pyoderma, demodicosis.

- Breed specific immune imbalances

21
Q

What may cause acne?

A

Dogs (and cats)
Often chronic and young animals
?Keratinisation defect
CAT: demodicosis, dermatophytosis, FeLV, FIV, allergies
DOG: short-haired breeds, any other causes

22
Q

Tx - acne

A

Systemic - to achieve initial remission

Topical - to maintain remission

23
Q

What does an acral distribution of a skin problem mean?

A

it affects distal portions of the limbs and head

24
Q

Outline acral lick dermatitis

A
  • often large breed dogs
  • often chronic
    >95% positive bacterial culutre
  • Tx = long term antibiosis and prevent trauma.
  • Causes - underlying joint disease, allergy, (behaviour - boredom)
25
Q

Tx - acral lick dermatitis

A
  • ABs (many systemic drugs licensed)
  • Topical ABs (can reduce need for systemic drugs, hard work, useful for recurrent pyodermas and multiresistant Stap).
  • Treat underlying conditions
  • Special considerations: recurrent pyoderma, zoonotic implications (rarely, MRSA), antimicrobial resistance)
26
Q

How long should pyoderma be treated?

A
  • Superficial: >3 weeks OR 1 week beyond complete clinical cure
  • Deep: >4-6 weeks OR 2 weeks beyond complete clinical cure.
  • Until underlying trigger addressed.
  • Beware - compliance
27
Q

List some biofilm-producing pathogens

A

GRAM POSITIVE: Staph and Strep, Enterococcus, Actinomyces, Corynebacterium, Bacillus
GRAM NEGATIVE: Serratia marcesens, Pseudomonas aeruginosa, Legionella, Moraxella, E.coli/Salmonella

28
Q

Why are biofilm-producing bacteria a problem?

A
  • no specific diagnostic techniques

- highly drug resistant (need up to 400 times MIC of planktonic bacteria = free-floating bacteria, i.e. no biofilm)

29
Q

Define biofilm

A

assemblages of microorganisms and their associated extracelluar products at an interface and typically attached to an abiotic or biotic surface.

30
Q

T/F: all strains of Pseudomonas can form biofilms

A

True

31
Q

T/F biofilm in canine otitis has a much higher resistance to neomycin, polymixin B, enrofloxacin and gentamicin

A

True

32
Q

Which pathogens are principally implicated in feline staphylococcal infection?

A

S.pseudintermedius
Others - S. aureus, rarely S.hyicus
S. felis - commonly present, found in lesions but status as pathogen is unclear

33
Q

Where is resistance in feline stap infections see?

A
  • feral cats

- non-pathogenic staph

34
Q

What are the likely environmental sources of feline staph?

A

medical waste, polluted water and rodents

35
Q

T/F: topical and systemic therapy is effective for superficial pyoderma

A

False - topical therapy alone is effective for superficial pyoderma

36
Q

Where are biofilms found? Tx?

A

Found in skin folds - don’t treat systemically