Skin Bacteria Review Flashcards
What is the most common isolate in dogs?
Staphylococci pseudintermedius
When staphylococcus isolates are macrolide(erythromycin) resistant, you also have to be concerned about…?
Inducible clindamycin resistance unless otherwise confirmed by D-test
What bacteria can be seen in a negative staining Giemsa stain?
Mycobacterium
What bacteria causes lymph node abscesses in cats?
Yersinia pestis (Plague)
What bacteria causes cat bite abscesses?
Pasteurella spp.
Woods lamp only causes fluorescence in which bacteria?
Microsporum canis
Treatment with Griseofulvin
Act only against dermatophytes, need oral administration uand the drug reaches the superficial dead epithelium (stratum corneum)
What is the pathogenesis of Erysipelothrix rhusiopathiae
Septicaemiae and endothelial cell damage
Skin lesions in Horses
Streptococcus equi subsp. equi Corynebacterium pseudotuberculosis Sporothrix schenkii Burkholderia mallei Histoplasma farciminosum Pythium insidiosum
What is the best treatment for a staph abscess?
Open, flush and clean
pyoderma/skin infections
- *coagulase positive staphylococcus (most common)
- *Pseudomonas
streptococcus corynebacterium arcanobacterium pasteurella proteus e. coli
**always investigate underlying causes such as allergy, ectoparasites, immunosuppressive conditions
Diagnostics for skin infections
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
Treatment for skin infections
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)
how to sample superficial lesions
culturette swab in transport media
how to sample abscesses
fine needle aspirate or contents in ANAEROBIC transport media
how to sample granulomatous lesions
sample for biopsy and a fresh piece of tissue for culture
other sample submission guidelines
for any non-resolving lesions a biopsy is always recommended
do not submit dry swabs for cultures
Anaerobic infections and sampling
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
Greasy pig disease/exudative epidermitis
staphylococcus hyicus
birds- bumble foot
staphyloccus aureus (anaerobe)
Botryomycosis
rodents, human, horses
chronic pyogranulomatous inflammation (giant mouse cheek)
most common isolate: S. aureus
wound infections, draining tracts, abscesses
aerobic bacteria: staph, strep, corynebacterium, myccobacterium, actinomyces, nocardia
gram + anaerobes: clostridium
gram - anaerobes: fusobacterium, bacteroides, dichelobacter
Dogs and cats with nonhealing cutaneous lesions and subcutaneous nodules
mycobacterium (negative stained rods, but gram +)
what stain do you use for dermatophilus congolensis
giemsa stain
cattle, sheep, goats, horses
dermatophytosis in cattle
trichophyton verrucosum
actinomyces bovis
lumpy jaw, pyogranulomatous osteomyelitis
fusobacterium necrophorum
cattle, sheep, goats
foot rot
mycotoxins (sporidesmin, pithomyces chartarum)
facial eczea due to photosensitization (fungal toxins)
cattle, sheep, goats
Mycotic infections of the skin
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
Persian cats
pseudomycetoma- Microsporum canis
no symptoms, just carrer
treatment of mycotic infections
azols (oral)
terbinafine
griseofulvin- only for dermatophytes
cryptococcus neoformans cutaneous manifestations
lungs, CNS, eyes, skin
blastomyces dermatitidis cutaneous manifestations
lungs primary, skin lesions in disseminated diease
sporothrix schenckii cutaneous manifestations
cutaneous/lymphatics
other fungus that shows cutaneous manifestations
prototheca, pythium insidiosum/lagenidium
