Fungal Infections II Flashcards
why is it so difficult to treat tinea unguium and what is best treatment
using topical treatments don’t work because it cannot penetrate the nail plate into the nail bed where the fungus resides
best to treat with oral systemic antifungal
what does epidermophyton attack and what is the only pathogenic species in this genus
skin and nails
e. floccosum
what is seen on agar of epidermophyton
just macroconidia which are smooth walled and large – born singly or in banana shaped clusters
no microconidia
what does microsporum attack and what is seen on agat
skin and hair
see more macroconidia than microconidia
treatments for dermatophytes
orally active triazoles allylamines (terbinafine) griseofulvin and ketoconazole thiocarbonates (tolnaftate) many imidazoles
what are control measure for opportunistic fungi like candida and molds
- discontinue antibiotics and restore normal flora
- restore immune system
- surgical removal of lesions and antimicrobials
most common mold in externa otitis
aspergillus species
next is fusarium
where do skin infections with candida usually occur
moist areas like between toes, folds of skin obese patients, diaper rash in infants
prevention of candidiasis of the skin
- clotrimazole or nystatin
- disposable diapers
- decrease moisture and chronic trauma in babies
what is Hyalohyphomycosis
generic name for many species of non black mold fungal infections but aspergillosis just so common that it has its own category
fusarium is an example of hyalohyphomycosis
what is Phaeohyphomycosis
term for black mold fungal infections not covered by older historical names like tinea nigra and such
what are chronic subcutaneous infection caused by
fungi or bacteria
what is another name for chromoblastomycosis (which is in fact a type of phaeophyphomycosis)
verrucous dermatitis
causative agent of chromoblastomycosis
black pigmented soil fungi –> philalophora and cladosporium
clinical presentation of chromoblastomycosis
wart like nodules that are slow growing and painless
most common fungal agent of eumycetoma
Pseudoallescheria boydii (Petriellidium boydii).
another name for eumycetoma
madura foot
how does eumycetoma/madura foot present
local swelling with suppuration and abscess formation
what is causative agent of sporotrichosis
Sporothrix schenckii.
how does one get infected by sporothrix schenckii
infection by splinters, thorns, and cuts of the skin
how do you treat sporotrichosis
oral potassium iodide (in milk)
how does sporothrix schenckii look like on microscopy
flower like sporulation
what predisposes one to fusarium
scatches, contact lenses
since this is an eye infection
with a wood’s light (UV) exam what do you see with tinea versicolor
fluoresces subtle gold colors
with a wood’s light (UV) exam what do you see with tinea capitis and what is the limit
fluoresces a ligher greenish blue only if it is the microsporum canis and microsporum audouinii species causing
what do you see with UV exam if tinea capitis is caused by trichophyton
no fluorescence – this will be the case for most tinea capitis since trichophyton is the most common agent
yeast infections in blood take how long to culture
2-7days
dimorphic fungi take how long to blood culture
2-6 weeks
what temp does mycobacterium marinum require to grow
28-30oC
what does mycobacterium marinum look like when exposed to light
yellow pigment (it is an acid fast photochromogen)
how can you identify mycobacterium marinum when clinically presented to you
cuts and abrasions of the skin usually hands while working in or around sea water or aquarium water
features of mycobacerium ulcers
- slow growing non photochromogen
- requires 28-30oC to culture
- commonly known as Buruli ulcer
what does mycobacterium chelonae cause
soft tissue abscesses and chronic cutaneous lesions
what is mycobacerium chelonae associated with
implants derived from living tissue
how do you treat m. chelonae
surgical excision plus cefoxitin and amikacin
