B.

CUTANEOUS FUNGI

 Invade/ destroy keratinized – hair, skin, nails

o Keratinolytic keratinase
o With inflammation  can deep to cutaneous
 Dermatophytes  dermatophytosis

CLASSIFICATION:

Origin

Anthropophilic Geophilic Zoophilic

Source: Humans soil Animal
*infected  uninfected
No. of conidia (culture medium) Few Most numerous Moderate
Tissue reaction Mild Severe Moderate
Examples Epidermophyton floccosum Microsporum gypseum Microsporum canis
Tricophyton equinum

Morphology

Epidermphyton Microsporum Tricophyton

Tissue/s infected Skin Hair Hair
Nails Skin Skin
Nails
Presence in tissues NO Some species NO
Teleomorph None/ unknown (Imperfect) Arthroderma/ Nannizia Arthroderma
*Anamorph
*Arthroconidia – able to damage the hair

A. Skin Infection

TINEA:

 Circular patterns, patches *numerous

 Reddish, itchy, scaly
 “ringworm”
 SKIN Tinea capitis Tinea barbae Tinea corporis Tinea cruris Tinea manuum Tinea pedis Tinea unguium Tinea imbricate
INFECTIONS
Characteristics: Ringworm of the Barber’s itch Body ringworm Ringworm of the *peeling – Ringworm of the Overlapping ring-
scalp “ringworm” groin interdigital areas nails like lesions
*Alopecia *scaly lesions Jock’s itch *Bullae – fluid- Nails  brittle, *Tricophyton
*circular patterns filled vesicle thickened, concentricum
discolored
Affected site: Head  scalp Bearded areas of Trunk Groin area Hands Soles Nails
Eyelashes the face Shoulders *Perineum and Palms Feet
Eyebrows Neck *Skin other than perianal areas Fingers
bearded area,
scalp, groin,
hands, or feet
*T. unguium - difficult to treat; oral anti-fungal drugs

B. Hair infection  Brittleness  loss of hair  Inside

 Growth of fungi along the length of  Inner layer
1. Ectothrix
the hair  Fungi – arthroconidia
 Outside
2. Endothrix 3. Favic
 Outer layers

 Worst type  Destroys inner, outer,  Destruction of tissues  almost death  Mousy odor  pus formation  yellow
subcutaneous of the tissues crust
 Inflammation  pus formation

Laboratory Diagnosis o M. canis o Endothrix & ectothrix infection vs. favic

type
Specimen: Direct Microscopy

 Skin scrapings  KOH Preparation

 Hair o Do not distinguish the dermatophytes  Calcofluor White (CFW) staining
 Nail clippings  Hyphae  Hyphae
o Small: 2-3 microns o Branching
Exposure to Wood’s Light
o Hyaline, septate, branching o Fluoresces
 Yellow-green fluorescence  Presence of arthroconidia
Culture:
o M. audouinii
 Primary isolation  Cycloheximide o Selective for dermatophytes
 Nonselective SDA o Includes:  Cycloheximide
o Do not inhibit saprophytic fungi  Mycosel (BBL)  Chlortetracycline
o 25-30°C for at least 1 week  Mycobiotic (Difco)  Gentamicin
 Maximum of 3 weeks  Dermatophyte test medium o Differential
 Selective SDA (DTM)  Phenol red
o Saboraud Dextrose Agar with  Modified SDA  Dermatophytes  alkaline
antimicrobial agents: o 25-30°C for at least 1 week products  reddish discoloration
 Chloramphenicol  Maximum of 3 weeks of agar
Dermatophyte test medium (DTM)
 Tricophyton tonsurans Tricophyton Tricpohyton Tricophyton Tricophyton violaceum Epidermophyton
concentricum verrucosum schoenleinii floccosum
Classification Anthropophilic
Wood’s Light (-) (-) (-) (-) (-) (-)
Colonial Characteristic Flat and velvety Folded and furrowed Commonly small Convoluted to folded Verrucose and glabrous Flat, slightly granular at
Convoluted with raised Glabrous to slightly first
center and flat periphery velvety
with some submerged Often submerged into
growth surrounding medium
Glabrous to slightly “mousy odor”
velvety
Pigmentation *color differ to medium
Obverse Yellow White but becoming White or cream White to tan Cream then becoming White which becomes
honey-brown lavender khaki-green brown
-center is folded
Reverse Yellow-brown to Yellow Colorless or salmon Colorless or light yellow Yellow-brown with
chestnut red-brown observable folds
Conidia Uncommon macroconidia No conidia Absent/ uncommon
and microconidia
Macroconidia Uncommon Uncommon “Snowshoes”
Absent or rare, distorted 3-5 cells “Paddles”
Small Thin-walled “Beaver’s tail”
pencil-/club-/cigar- “Rat-tail extension”
shaped
Thick walls
3-8 cells
Microconidia Various size and shapes Abundant No microconidia
with flattened base Large
Abundant Clavate
Teardrop-/club-shaped
“Balloon forms”
- Aged pleomorphic
microconidia
- Broad matchstick
Hyphae Terminal chlamydospore Masses of tangled hyphae Favic chandeliers, Swollen hyphae
with chlamydospores antlers, nail head containing cytoplasmic
granules
 Microsp Microsp Microsp Tricophyton Tricophyton
orum orum orum mentagrophytes rubrum
audouin canis gypseu Type I Type II Type I Type II
ii m
Classifi Zoophili Geophili Zoophilic Anthropo Anthropophilic
cation c c philic
Wood’ Yellow- Yellow- (-) (-) (-) (-) (-)
s Light green green
fluoresce fluoresc
nce ence
Coloni Flat, Cottony Flat and Flat and Flat and Cottony Powdery
al velvety, and granular granular powdery and to low
Charac thin granular to to cottony velvety velvety
teristic powdery
Pigme
ntatio
n
Obvers Light: white to Cinnamo yellow yellow White to Cream to
e white, buff n- cream to cream to reddish deep red
light colored buff buff
brown

Revers Pale Yellow, Light tan Pale to Pale to Wine- Wine-

e salmon rarely red- red- red red
to pale pale brown brown
brownis
h:
Orange-
red
Conidi Uncom More conidia in Type I More conidia in
a mon than in Type II Type II than in Type I
*Ovoid if
present
Macro 6 – 15 3-9 Uncommon Pencil-shaped
conidi cells celled, Cigar/ pencil/club- Cigar-shaped
a Asymme broadly shaped Thin walled
trical spindle- Thin, smooth walls Broad bases
beaked shaped, 3-6 cells 3-8 cells
apex rough-
walled
Terminal
ends
may be
rounded
Microc Clavate if Globose Clavate or Tear-shaped
onidia or present, & pyriform Club-shaped
PHYSIOLOGICAL TESTS  Acquire strands of hair → LPCB → Microscope
 Positive result: wedge-shaped perforation into the hair
Polished Rice Test
 Negative result: no perforeation
 Purpose: M. canis vs. M. audouinii
Urease test
M. canis Positive growth
 Culture medium
M. audouinii Negative growth
o Christensen’s agar
 Procedure:
o Stuart’s broth
o Medium: Rice grains (8 grams) with distilled water (2.5ml)
 Purpose: T. mentagrophytes vs. T. rubrum
o Sterilize: 15 mins @ 125°C (autoclave)
T. mentagrophytes Positive
o Plate
T. rubrum Negative
o Transfer colonies from primary isolation medium
 Result (Christensen’s medium)
o Incubation:
o Positive: red to purple color in less than 4 days of incubation
 Room temperature
o Negative: No color change
 6-10 days
Growth factor test
 25-30°C
 Casamino acid agar/ Tricophyton agar
 Result: Rice grains → Yellowish = positive
o Nicotinic acid
Hair Perforation test
o L-Histidine
 Purpose: T. mentagrophytes vs. T. rubrum
o Growth factors
T. mentagrophytes Positive
 Thiamine
T. rubrum Negative
 Inositol
 Other dermatophytes with positive results:
 2 Plates:
o M. canis
o Plate 1
o M.gypseum
 Nicotinic acid
o T. tonsurans
 L-Histidine
o T. violaceum
 Inositol
 Culture medium: yeast extract in distilled water
o Plate 2
o 10% yeast extract – 10 grams yeast + 100ml d.water
 Nicotinic acid
o Add strands of hair
 L-Histidine
 Juvenile hair (≤1 cm)
 Inositol
o Sterilize: 15 mins @ 125°C (autoclave)
 Thiamine
o Plate → filter paper → overlay yeast extract (2-5 ml) → 10-12 hair  T. verrucosum: (+) inositol
strands  T. violaceum (+) inositol and thiamin
o Incubate up to 4 weeks at room temperature