Skin Bacteria Review

Question 1

What is the most common isolate in dogs?

Answer 1

Staphylococci pseudintermedius

Question 2

When staphylococcus isolates are macrolide(erythromycin) resistant, you also have to be concerned about…?

Answer 2

Inducible clindamycin resistance unless otherwise confirmed by D-test

Question 3

What bacteria can be seen in a negative staining Giemsa stain?

Answer 3

Mycobacterium

Question 4

What bacteria causes lymph node abscesses in cats?

Answer 4

Yersinia pestis (Plague)

Question 5

What bacteria causes cat bite abscesses?

Answer 5

Pasteurella spp.

Question 6

Woods lamp only causes fluorescence in which bacteria?

Answer 6

Microsporum canis

Question 7

Treatment with Griseofulvin

Answer 7

Act only against dermatophytes, need oral administration uand the drug reaches the superficial dead epithelium (stratum corneum)

Question 8

What is the pathogenesis of Erysipelothrix rhusiopathiae

Answer 8

Septicaemiae and endothelial cell damage

Question 9

Skin lesions in Horses

Answer 9

Streptococcus equi subsp. equi
Corynebacterium pseudotuberculosis
Sporothrix schenkii
Burkholderia mallei
Histoplasma farciminosum
Pythium insidiosum

Question 10

What is the best treatment for a staph abscess?

Answer 10

Open, flush and clean

Question 11

pyoderma/skin infections

Answer 11

• *coagulase positive staphylococcus (most common)
• *Pseudomonas

streptococcus
corynebacterium
arcanobacterium
pasteurella
proteus
e. coli

**always investigate underlying causes such as allergy, ectoparasites, immunosuppressive conditions

Question 12

Diagnostics for skin infections

Answer 12

Skin scraping to rule out parasites (demodex)
fungal culture to rule of deep fungal infection
cytology- impression smear of pustules, papules, crusts or draining tract fluid
bacterial culture/susceptibility testing-fresh purulent discharge or tissue
skin biopsy- dermatohistopathology

Question 13

Treatment for skin infections

Answer 13

systemic antibiotics based on culture and susceptibility (up to 8 weeks+ in refractory cases)

Fluoroquinolones- tissue penetration, activity against gram + and -, uptake by macrophages increases penetration and concentration

Clindamycin- consider inducible resistance (macrolide resistence esp)

Anitbacterial topical therapy (chlorhexidine)

Question 14

how to sample superficial lesions

Answer 14

culturette swab in transport media

Question 15

how to sample abscesses

Answer 15

fine needle aspirate or contents in ANAEROBIC transport media

Question 16

how to sample granulomatous lesions

Answer 16

sample for biopsy and a fresh piece of tissue for culture

Question 17

other sample submission guidelines

Answer 17

for any non-resolving lesions a biopsy is always recommended

do not submit dry swabs for cultures

Question 18

Anaerobic infections and sampling

Answer 18

foul smelling discharge, necrotic gangrenous tissue and abscess formation, free gas in tissue, black discoloration of exudates, sulphur granules in discharge

disinfect skin surface with 70%alcohol and let dry
aspirate directly into syringe
remove air from syringe
aseptically transfer material into an anaerobic transport media

Question 19

Greasy pig disease/exudative epidermitis

Answer 19

staphylococcus hyicus

Question 20

birds- bumble foot

Answer 20

staphyloccus aureus (anaerobe)

Question 21

Botryomycosis

Answer 21

rodents, human, horses
chronic pyogranulomatous inflammation (giant mouse cheek)
most common isolate: S. aureus

Question 22

wound infections, draining tracts, abscesses

Answer 22

aerobic bacteria: staph, strep, corynebacterium, myccobacterium, actinomyces, nocardia

gram + anaerobes: clostridium

gram - anaerobes: fusobacterium, bacteroides, dichelobacter

Question 23

Dogs and cats with nonhealing cutaneous lesions and subcutaneous nodules

Answer 23

mycobacterium (negative stained rods, but gram +)

Question 24

what stain do you use for dermatophilus congolensis

Answer 24

giemsa stain

cattle, sheep, goats, horses

Question 25

dermatophytosis in cattle

Answer 25

trichophyton verrucosum

Question 26

actinomyces bovis

Answer 26

lumpy jaw, pyogranulomatous osteomyelitis

Question 27

fusobacterium necrophorum

Answer 27

cattle, sheep, goats

foot rot

Question 28

mycotoxins (sporidesmin, pithomyces chartarum)

Answer 28

facial eczea due to photosensitization (fungal toxins)

cattle, sheep, goats

Question 29

Mycotic infections of the skin

Answer 29

dermatophytosis:
trychophyton
microsporum
epidermophyton

dogs: M. canis, m. gypsium, t. mentagrophytes
cats: m. canis
horses: t. mentagrophytes, t. equinum
cattle: t. verrucosum
pigs: m. nanum

Question 30

Persian cats

Answer 30

pseudomycetoma- Microsporum canis

no symptoms, just carrer

Question 31

treatment of mycotic infections

Answer 31

azols (oral)
terbinafine
griseofulvin- only for dermatophytes

Question 32

cryptococcus neoformans cutaneous manifestations

Answer 32

lungs, CNS, eyes, skin

Question 33

blastomyces dermatitidis cutaneous manifestations

Answer 33

lungs primary, skin lesions in disseminated diease

Question 34

sporothrix schenckii cutaneous manifestations

Answer 34

cutaneous/lymphatics

Question 35

other fungus that shows cutaneous manifestations

Answer 35

prototheca, pythium insidiosum/lagenidium