-
what are the portals of entry for fungi
- sinus
- blood
- lungs
- skin
- esophagus
- stomach
- intestine
-
what are the common sites of infection for deep/systemic mycoses
- brain
- lungs
- heart
- liver
- spleen
- kidney
-
protocol when receiving specimen
know this
-
protocol for IDing growth
know this
-
What is the fungi protocol for respiratory specimen
- use fungal media, media with antibiotics, or KOH prep
- digest with trypsin
-
what is the fungi protocol for nail specimen
- use scrappings/cuttings
- use KOH wet mount or fungal media
-
what are some methods with identifying fungal agents
- rapid report
- morphological characteristics
- gram stain
- KOH prep, silver stain
- India ink
- tissue stains
-
for what specimens do you use india ink
- CSF
- crytococcus neoformans
-
what specimens do you use tissue stains
- PAS
- Giemsa
- GMS silver
- Masson-Fontana
-
what are some media used for bact culture
- SDA (sabouraud dextrose agar): main media
- SDA with antibiotics
- BHI agar (brain-heart infusion)
-
when do you use cyclohexamide antibiotic on an SDA
for suspecting dermatophytes
-
what is clear significant clinical characteristic that dermatophytes produce
ringworm
-
what are some antibiotics used on an SDA
- chlorahexamide
- chloramphenicol
-
what is the content of BHI agar
- blood
- antibiotics
- neutral pH (emmons modification)
-
at what temp and time do you incubate BHI agar
-
What is the procedure for analyzing growth on an agar
- examine weekly
- # of days til growth
- mold/ yeast
- culture media
- temperature of growth
- morphology of colonies
- pigment on reverse side
- aerial mycelium
-
what is the direct microscopic exam for fungal structures
direct mount: stain w/ KOH, calcofluor white stain, HE
-
what stain do you use with tease mount
lactophenol cotton blue
-
what are the types of dermatophytoses
- keratinophilic: grow on nails, hair and skin
- geophilic: inhabit soil, produce large numbers of conidia
- zoophilic: on animals, spread to humans
-
what type of genus causes ring shaped (ringworm) patterns in skin. Where is ringworm commonly found
- Genus: Tinea
- head, beard, body, nails, feet
-
what are the types of genus that infect hair follicles
- tineae favosa (favus) or T.shoenleinii
- tinea capitis: produce gray patch ring worm on kids. Located on outer portion of hair shaft (ectothrix)
- m. audouinii: ectothrix
-
how can ectothrix be identified
woods light: long wave UV light which
-
which type of endotrhix infection does not fluoresce with woods light
trichophytes
-
what are ectothrix infections
- arthrospores that appear as mosaic sheaths around hair or on surface of hair shaft
- cuticle remains intact
- microsporum
-
what occurs during endothrix infections
- hyphae form arthrospores within the hair shaft
- cuticle gets destroyed
-
what type of funi causes ectothrix infections
- t. mentagrophytes
- m. canis
- m. gypseum
- m. audouinii
- t. verrucosum
- t. rubrum
-
what type of fungi cause endothrix
- t. schoenleinii
- t. tonsurans
- t. violaceum
- t. soudanense
-
what is another name for nail and nail bed infections by fungi
- onychomycosis
- difficult to treat
-
what fungi usually cause nail and nail bed infections
- griseofulvin
- trichophyton species
-
what types of infections cause athlete's foot
- tinea pedia: mostly men
- produces mocassin foot, associated with scaling, fissures, and erythema
-
how to treat athelete's foot (3)
- keratinolytic agents: removing outer layer of skin with the fungal elements
- griseofulvin: for extensive tinea corporis
- recurrence: for common ring worms
-
what are the characteristics of trichophyton mentagrophytes (infection site, colony characteristics, causes, urease -/+, macro/micro conidia)
- microconidias: pencil shaped, thin walled with 5-8 cells
- infects:skin, hair nails
- culture: fluffly white, granular (buff, tan)
- no red pigment
- urease +
- ectothrix invasion
- common cause of athelete's foot
- hair perforation: +
-
what are the characteristics of T. Rubrum (infection site, colony, causes, urease -/+, macro/micro conidia, hair perforation -/+)
- most common species in ringworms
- infects: skin, nails, RARELY HAIR
- culture: white colonies
- urease (-)
- macroconidia
- **reverse side: deep red pigment
- hair perforation: -
-
what are procedures used to distinguish t.mentag from t.rubrum
- pigmentation
- 5 day urease
- hair perforation
-
what are the characteristics of T. tonsurans
- infects: hair, skin, nails
- black dot tinea capitis
- anthrophilic
- small number of peg shaped microconidia
- rare macroconidia
-
how to distinguish T. tonsurans from T. rubrum and T. mentag
culture for thiamine
-
what is the most common microscoprum infecting humans
- m. canis
- infects skin and hair
-
what is the characteristic of m. canis (culture, macro/microconidia)
- culture: lemon yellow color
- macroconidia: spindle shaped, thick walled, tapered ends
- dermatophytosis of boy and scalp
- contracted from dogs
-
what is the media that produces good growth of m. canis
rice grain media
-
what are the characteristics of M. gypseum (infection site, macro/microconidia, found in)
- geophilic (soil)
- infects: hair
- macroconidia: numerous, elliptical and fusiform
- does not commonly infect humans
-
what are the common characteristics of M. audouinii (growth on media, what type of media, infection site, macro/microconidia)
- causes: gray patch ringworm in kids
- infects: hair and skin
- rare macro conidia
- mostly microconidia
- poor growth on polished rice grains
-
what is the most prevalent fungi that cause ringworm
T. tonsurans, used to be M. Audouinii 20 years ago
-
characteristics of epidermophyton floccosum (infection site, colony, macro/microconidia)
- colony: yellow or yellow green
- macroconidia
- no microconidia
- infects: skin and nail
-
How to identify epidermophyton floccosum
- specimen collection: hair, skin scrapings, nails
- KOH prep on skin
- inhibitory agar: SDA, BHI, DTM
- non inhibitory agar: saboraud BHI, BHI with blood, SDA
-
what is Wood lamp used to ID and for what dermatophytes
- scalp lesions fluoresce green or yellow
- m. canis, m. audouinii, T. tonsurans
-
what is hair perforation used to test and for what dermatophytes
- hair fragments mixed with conidia
- T. rubrum (-)
- T. mentag (+)
-
what is urease used to test and for what dermatophytes
- christensen urea agar
- T. mentag: +
- T. rubrum: -
-
what is growth on rice grains used for
all microscporum except M. audouinii
-
know the types of micro/macro conidia of microsporum, epidermophyton, trichophyton
|
|
