Microbiology Lecture 10 - Subcutaneous Mycoses (Palindrome)

SUBCUTANEOUS MYCOSES Note: Transcription is based from the manual and the transcriber’s notes

SUBCUTANEOUS MYCOSES  Chronic, localized infections of the skin and subcutaneous tissue following traumatic implantation of etiologic agent  Rare, exotic, under the skin  Insidious cause  MOT: accidental puncture  Causative fungi are all soil saprophytes of regional epidemiology; soil and vegetation saprophytes (decaying organic material)  Considered as occupational hazard  Lesions are deeply rooted  Difficult to treat some require surgical intervention  Patients are not immunocompromised  Tx: systemic antifungals, surgical excision

Disease Sporotrichosis Chromoblastomycosis

Mycotic Mycetoma

Rhinosporidiosis Lobomycosis

Etiologic Agent Sporothrix schenkii Phialophora Cladosporum Fonseca Pseudallescheria Madurella Exophiala Acremonium Rhinosporidium seeberi Loboa loboi

SPOROTRICHOSIS  Etiologic agent: Sporothrix schenkii  Rose handler’s disease  Chronic infection with involvement of adjacent lymphatics, subcutaneous nodules, ulcers (painless chanre  sporotrichotic chanre), suppuration  Nodular with suppuration and ulceration  Common in tropical or temperate region  Dimorphic o Yeast/Tissue phase: budding yeast (asteroid body) cigar body o Mold phase: rosette microconidia (at the tip)  CLINICAL MANIFESTATION o Forms:  Lymphotcutaneous type – most common; skin and lymphatic channel

involvement (multiple nodules, cordlike nodules)  Fixed cutaneous type  Disseminated type – poor prognosis  Pulmonary type – rare; resemble TB  LABORATORY DIAGNOSIS o Microscopic examination  Thermo – dimorphic  Tissue phase – budding yeast cell  CIGAR BODY  Mold phase – microconidia  DAISYLIKE or ROSETTE o Culture  early: moist; whitish, not cottony  Older: more vegetative cell; whitish filamentous becoming brownish  Mold: SDA with cycloheximide  Yeast: BHIA o Histopathology  Inflammation: central area with acute suppuration  Organism: fluorescent technique o Serology  Precipitation test  TREATMENT o Oral potassium iodide (MOA: unknown) o Amphotericin B – for extracutaneous forms o Antimicrobial therapy – for secondary bacterial infection

CHROMOCYTOSIS  Etiologic agent: o Phialophora verrucosa – most common o Cladosporum cerrionii o Fonseca pedrosol o Fonseca compactum  Chromoblastomycosis, chromomycosis  Verrucous dermatitis  Common in temperate countries  DEMATACEOUS FUNGI  melanin-like pigment (black, rubbery)  Dimorphic o Yeast/Tissue phase: sclerotic bodies, Medlar bodies, brown bodies, fission bodies, cannot distinguish the species o Mold phase: fine hyphae and various types of sporulation; distinguishes the species

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SUBCUTANEOUS MYCOSES Note: Transcription is based from the manual and the transcriber’s notes

 CLINICAL MANIFESTATIONS o Chromoblastomycosis  Verrucous, warty nodules  Progress, vegetate and take a cauliflower-like appearance o Phaeohyphomycosis  Solitary encapsulated cyst  phaeohyphomycotic cyst  LABORTORY DIAGNOSIS o 3 types of sporulation  Phialophora – FLASK-SHAPED phialides  Cladosporium – branching conidiophores, with CHAINS of conidia  Acrotheca – CLUB-SHAPED conidiophores with conidia arising at lateral sides; Fonseca  TREATMENT o Surgical removal o Amphotericin B + 5 fluorocytosine

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MYCETOMA Etiologic agent: species of true higher fungi Madura foot Maduramycosis Only lesion where granules can be seen from the discharge Triad of mycetoma o Draining sinuses o Abscess o Granules Lesion: abscess, granulomata and draining sinuses, tumefaction Incubation period: years CLINICAL MANIFESTATION o Actinomycotic mycetoma  Filamentous BACTERIA masquerading like fungi  Causative agents (NASA)  Nocardia  Actinomadura  Streptomyces  Actinomycetes  bacterial infection  fine threads of bacilli  IP shorter than 5 years

 Earlier involvement of bone o Eumycotic mycetoma  TRUE FUNGI  Causative agents  Madurella  Pseudallescheria  Exiophiala  Leptoshaeria  Curvularia  Fusarium  Lesion: chronic granulomatous lesion involving the foot, characterized by multiple draining sinus tracts; granules are seen in the discharge  LABORTORY DIAGNOSIS o Demonstration of granules in the discharge  TREATMENT o Surgical amputation o Amphotericin B o Antibiotics (if actinomycotic form)

LOBOMYCOSIS Etiologic agent: Loboa loboi Lobos disease Keloidal blastomycosis Found in Mexico and southwards of Central Brazil  CLINICAL MANIFESTATIONS o Rare, progressive disease of the skin and subcutaneous tissue o Lesions vary in appearance according to the duration of infection o Sites: limb and face o No discomfort o Early stage: single nodule – 1cm o Late stage: elevated and keloidal with satellite lesion  LABORATORY DIAGNOSIS o Direct microscopic examination o KOH – chain of yeast cell  TREATMENT: Surgical excision    

RHINOSPORIDIOSIS  Etiologic agent: Rhinosporidium seeberi  Common in India and Sri Lanka  Males from rural areas with frequent contact with freshwater pools  CLINICAL MANIFESTATIONS

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SUBCUTANEOUS MYCOSES Note: Transcription is based from the manual and the transcriber’s notes

o Chronic granulomatous disease of the mucocutaneous tissue (eyes, oral cavity) o Large polyps or wart-like lesions  dangling pedunculated  with stalk o Most commonly affected area: NOSE  Pedunculated  Extrude from nostril  Large pink to red cauliflower-like masses o Conjunctiva of the eyes  Unilateral  May be pedunculated o Anus, vagina, and ears (rare) o Cutaneous lesion  extension from infected mucosa o Source: unknown  LABORATORY DIAGNOSIS o Host tissue  Large sporangia (spherules)