Fungi

Superficial Mycoses

Forms of fungi

Hyphae (filamentous)

Yeast (single cell)

Reproduce by spores

Reproduce by budding

Reproduce via Sabouraud's medium

Selective for fungi

Due to low pH

Due to antibiotics to kill bacteria

Dermatophyte

General characteristics

Infection in skin and hair, ability to obtain nutrients from keratinized material

Inflammation is a host response, not caused by fungi

Restricted to non-living cornified layer of epidermis, inability to penetrate viable tissue

If invade subcutaneous, it will form a kerion

Diagnosis methods

Wood lamp's examination

Direct microscopy of 30% KOH to identify hyphae and spores

Saboroud's agar

Special stains:

  • Gomori silver methanamine
  • Periodic acid stiff stain
  • Parker's ink (Trichosporon beigellii)
  • India's ink (Crytpcoccus)

Different strains

Trichophyton 🖊

Microsporum Canis 🖊

Epidermophyton floccusum 🖊

T. mentagraphyte var granulare

T.mentagraphyte var interdigitale

Spiral hyphae

Spiral hyphae

SKIN AND HAIR

GROIN and FOOT

"Hong kong foot" 🎉

Spread via wet surface and close contact

T. rubrum

SKIN AND NAIL

Spread via wet surface and close contact

Most common fungal infection in SG 🎉

SCALP AND HAIR

Acquired from dogs and cats

Commonly causes:

  • Ring worm
  • Tinea
  • Dermatophytosis

GROIN AND FOOT

Human Transmission

Tinea = ring worms

  • Tinea pedis (feet) = Athelete's foot
  • Tinea capitis (scalp)
  • Tinea corporis (body)
  • Tinea cruris (groin)

Yeasts

Trichosporon beigelii 🖊

Piedraia horlae 🖊

Nattrasia mangifera 🖊

Asperigillus Niger 🖊

Fusarrem 🖊

Malassezia furfur 🖊

Exophiala wernickii 🖊

Thick walled yeast

Sphagetti and meatball appearance 🎉

Requires oil to grow

Normal flora

Tinea versicolour 🎉

  • Folliculitis
  • Dermatitis
  • Peritonitis
  • Dandruff

Thick wall RHOMBOID hyphae

Causes Black peidra 🎉

infection of scalp hair forming black granules

Causes White peidra 🎉

infection of scalp hair forming white granules

hyphae and spores taken up by PARKER'S INK shows WRINKLED COLONIES 🎉

Fast growing black colonies 🎉

Causes onchomyosis (tinea nail)

Causes otomyosis

Fungal ball in outer ear 🎉

Corneal Ulcers 🎉

CLASSIC: Tinea nigra🎉

Hyperpigmented (dark/reddish) macule on palms and soles

Subcutaneous mycoses

Sporotrichosis 🖊

Chromoblastomycosis 🖊

Mycetoma 🖊

Rhinosporidosis 🖊

Found in soil, wood and plants

Thermally diphormic 🎉

  • 37 degree: Round cigar shaped yeast
  • 25 degree: septet hyphae with rosette clusters of conidia

Causes nodules with lymphatic spread

Primary site: LUNGS

"Copper penny bodies- coloured spores" 🎉

Enter via wood punctures

Causes papules on lower extremities 🎉

Systemic dissemination rare

verrucous cauliflower-like lesions

Found in soil plants, enter via open wounds

Causes Madura's foot 🎉

Abscess formation with draining sinuses containing sulphur granules

Harder to treat than bacterial matura's foot

Found in fish and aquatic insects in stagnant water

Causes polypoid masses at the nasal, conjunctival mucosa, genital 🎉

Seropurulent discharges from lesions

Diagnosed with spherules filled with endospores

Systemic Mycoses

  • Usually thermally dimorphic
  • Normally inhalation first then disseminated infection
  • Mostly asymptomatic
  • Usually found in soil

Coccidioides 🖊

Histoplasma 🖊

Blastomyces 🖊

Paracoccidiodomycosis :

Spread by sandstorm 🎉

37: spherules with endospores
25: hyphae causing barrel shaped orhtrocanida

Implicates reticuloendothelial system 🎉

37: Yeast cells
25: Mold

Saprophytic 🎉 - grows on dead or decomposing matters

Found in soil and avian habitats

common spread to skin

37: yeast cells with buds attached to parents by a broad base
25: mold

37: yeast cells with buds attached to parents by a broad base
25: mold

common in central & south america

OTHERS KEY

Candida 🖊

Cryptococcus 🖊

Aspergillus 🖊

Mucor 🖊

Penicillin marneffei 🖊

Pneumocystis 🖊

Distinguished by pseudohyphae under microscopy 🎉

Normal flora on skin

Groups that are prone to infection:

  • immunoD
  • broad spectrum antibiotics
  • IV administration, catheters
    Hyperalimentation: superficial supply of nutrients

Clinical presentation

Development of trush 🎉

UTIs

Lung infection with endobronchial and hematogenous spread

Candidemia

  • Infect all layers of heart
  • Spread to kidney, perinephric abscess or papillary necrosis
  • Perforatio of GIT, peritoneal infection

Thick glycoprotein helps extract nutrients from soil

Cryptococcus neoformans
Crytococcus gatti

Meningitis 🎉 not as acute as bacterial

Pneumonia 🎉

Antigens may be sequestered into the prostate after clearance from the rest of the body

Umbilicated lesions 🎉

Similar to what molluscum contagiosum gives

Found in hay

Predisposing factors:

  • ImmunoD
  • Construction activities 🎉
  • pre-existing lung problems

Transmission airborne

Clinical features

Allergic bronchopulmonary aspergillosis

Invasive aspergillosis

Begins at lungs 🎉

Asthema like symptoms Hypersensitivity reaction

Safety pin shaped yeast 🎉

Bright red mould

Causes papule and abscess

Causes penumocystic pneumonia 🎉

Pneumocystic jirocevi
Pneumocystic carinii

Usually begins as a lung infection that spreads systematically

Rhinocerebral mucromycosis = infection upwards towards nose through sinuses to the brain

Capsulated so can use for ink