Fungal Infections II

Question 1

why is it so difficult to treat tinea unguium and what is best treatment

Answer 1

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

Question 2

what does epidermophyton attack and what is the only pathogenic species in this genus

Answer 2

skin and nails

e. floccosum

Question 3

what is seen on agar of epidermophyton

Answer 3

just macroconidia which are smooth walled and large – born singly or in banana shaped clusters

no microconidia

Question 4

what does microsporum attack and what is seen on agat

Answer 4

skin and hair

see more macroconidia than microconidia

Question 5

treatments for dermatophytes

Answer 5

orally active triazoles
allylamines (terbinafine)
griseofulvin and ketoconazole
thiocarbonates (tolnaftate)
many imidazoles

Question 6

what are control measure for opportunistic fungi like candida and molds

Answer 6

• discontinue antibiotics and restore normal flora
• restore immune system
• surgical removal of lesions and antimicrobials

Question 7

most common mold in externa otitis

Answer 7

aspergillus species

next is fusarium

Question 8

where do skin infections with candida usually occur

Answer 8

moist areas like between toes, folds of skin obese patients, diaper rash in infants

Question 9

prevention of candidiasis of the skin

Answer 9

• clotrimazole or nystatin
• disposable diapers
• decrease moisture and chronic trauma in babies

Question 10

what is Hyalohyphomycosis

Answer 10

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

Question 11

what is Phaeohyphomycosis

Answer 11

term for black mold fungal infections not covered by older historical names like tinea nigra and such

Question 12

what are chronic subcutaneous infection caused by

Answer 12

fungi or bacteria

Question 13

what is another name for chromoblastomycosis (which is in fact a type of phaeophyphomycosis)

Answer 13

verrucous dermatitis

Question 14

causative agent of chromoblastomycosis

Answer 14

black pigmented soil fungi –> philalophora and cladosporium

Question 15

clinical presentation of chromoblastomycosis

Answer 15

wart like nodules that are slow growing and painless

Question 16

most common fungal agent of eumycetoma

Answer 16

Pseudoallescheria boydii (Petriellidium boydii).

Question 17

another name for eumycetoma

Answer 17

madura foot

Question 18

how does eumycetoma/madura foot present

Answer 18

local swelling with suppuration and abscess formation

Question 19

what is causative agent of sporotrichosis

Answer 19

Sporothrix schenckii.

Question 20

how does one get infected by sporothrix schenckii

Answer 20

infection by splinters, thorns, and cuts of the skin

Question 21

how do you treat sporotrichosis

Answer 21

oral potassium iodide (in milk)

Question 22

how does sporothrix schenckii look like on microscopy

Answer 22

flower like sporulation

Question 23

what predisposes one to fusarium

Answer 23

scatches, contact lenses

since this is an eye infection

Question 24

with a wood’s light (UV) exam what do you see with tinea versicolor

Answer 24

fluoresces subtle gold colors

Question 25

with a wood’s light (UV) exam what do you see with tinea capitis and what is the limit

Answer 25

fluoresces a ligher greenish blue only if it is the microsporum canis and microsporum audouinii species causing

Question 26

what do you see with UV exam if tinea capitis is caused by trichophyton

Answer 26

no fluorescence – this will be the case for most tinea capitis since trichophyton is the most common agent

Question 27

yeast infections in blood take how long to culture

Answer 27

2-7days

Question 28

dimorphic fungi take how long to blood culture

Answer 28

2-6 weeks

Question 29

what temp does mycobacterium marinum require to grow

Answer 29

28-30oC

Question 30

what does mycobacterium marinum look like when exposed to light

Answer 30

yellow pigment (it is an acid fast photochromogen)

Question 31

how can you identify mycobacterium marinum when clinically presented to you

Answer 31

cuts and abrasions of the skin usually hands while working in or around sea water or aquarium water

Question 32

features of mycobacerium ulcers

Answer 32

• slow growing non photochromogen
• requires 28-30oC to culture
• commonly known as Buruli ulcer

Question 33

what does mycobacterium chelonae cause

Answer 33

soft tissue abscesses and chronic cutaneous lesions

Question 34

what is mycobacerium chelonae associated with

Answer 34

implants derived from living tissue

Question 35

how do you treat m. chelonae

Answer 35

surgical excision plus cefoxitin and amikacin