Mycology - 02 Mycoses

MYCOLOGY INFECTION OF THE SKIN FUNGAL DISEASES / MYCOSES • OUTLINE • • • • • Superficial/Cutaneous Mycoses o Superficial Mycoses o Cutaneous Mycoses Subcutaneous Mycoses Systemic Mycoses o Deep Mycoses Opportunistic Mycoses Major Mycoses and Causative Fungi SUPERFICIAL / CUTANEOUS MYCOSES SUPERFICIAL MYCOSES • • • • • Affects only the cornified layers of epidermis (stratum corneum) Pityriasis versicolor / Tineaversicolor o Found world-wide but more common in tropical than temperate climates. o Also known as An-An o It is the discoloration, depigmentation and scaling of the skin and apparent in person with dark complex o Causative Agent - Malassezia furfur o Culture: It requires lipid for growth the reason why culture medium is overlaid with olive oil. Presence of “ Bowling Pin “ Appearance with collarette in culture media. Tinea nigra o It is a dark brown to black painless patches on the soles of the feet and palms of the hand o Sometimes confused to malignant melanoma o Causative Agent - Exophiala werneckii or Phaeoannellomyces werneckii o Culture: Shiny, moist yeastlike colonies that start with brownish discoloration and eventually turns to olive to greenish black. White Piedra o Affects beard and mustache hair shaft o Causative Agent - Trichosporon beigelii o Culture: colonies are white or yellowish to deep cream colored, smooth, wrinkled, velvety and dull in appearance with a mycelial fringe. Black Piedra o Affect the hair’s hair shaft o Causative Agent - Piedra hortae o Microscopic: thick walled rhomboid cells containing ascospores • • • • CAUSATIVE AGENTS • • • • Affect the keratinized tissue of the skin, hair and nails Also known as Ringworm Hyaline(moniliaceous) means non pigmented or lightly pigmented Dematiceous mold means pigmented, dark in color, usually gray to black. Infection of Skin o Trichophyton rubrum o Epidermophyton floccosum o Trichophyton mentagrophytes Infection of the Hair o Ectothrix / Endothrix o Tinea barbae o Tinea capitis o Microsporum canis o Trichophyton verrucosum o Trichophyton tonsurans ▪ 2nd most common cause of infection of the hair ▪ Severe infection of the scalp and skin “favus” Infection of the Nail o Tinea unguium ▪ Also known as Onchomycosis ▪ Caused by T. mentagrophytes, T.rubrum, & E. floccosum SUBCUTANEOUS MYCOSES • Involves subcutaneous muscle and tissues SPOROTRICHOSIS • • • Rose Gardener’s Disease/ Rose handler’s disease Sporothrix schenckii Dimorphic fungi CHROMOBLASTOMYCOSIS • • • CUTANEOUS MYCOSES/ DERMATOPHYTES • • • Tinea corporis o Also known as “BUNI” o Pruritic Tinea cruris o Also known as “HADHAD” o Red patched on the groin and scrotum Tinea pedis o Also known as ALIPUNGA or Athlete’s Foot o Cracking and peeling of skin that begins in the between of the toes Tinea manum - Hand and Finger Caused by variety of copper colored soil saprophytes which are non-healing tumor like lesions resembling cauliflower Also known as “Copper pennies” Causative Agents of Chromoblastomycosis based on morphology o Phialophora verrucosa o Cladosporium carrionii o Fonsecaea pedrosoi MADUROMYCOSIS • • • Granulomatous tumor of subcutaneous tissues characterized by tumor like deformities Causative Agent is Pseudoallesheria boydii Three Forms: o F. pedrosoi o P, verrucosa o C. carrionii • o Actinomyces/ Nocardia is called actinomycotic mycetoma o Most common isolate to human is Actinomyces israeli o Most common isolate to human is Nocardia asteroides PHAEOHYPHOMYCOSIS • • • rare infection by dermaticeous saprobes invading organs like skin, lungs and brain of immunosuppressed host mycotic disease caused by darkly pigmented fungi or fungi with melanin on the cell wall causative agent is Exophiala jeanselmei • • SYSTEMIC MYCOSES SYSTEMIC MYCOSES/ DEEP MYCOSES • • • • • • • • Caused by Dimorphic Fungi Acquired through inhalation Localized lung infection and bloodstream infection Blastomycosis / Gilchrist Disease / North American Blastomycosis/ Chicago disease o higher incidence to middle aged man due to recreational exposure to soil o causative agent - Blastomyces dermatitidis Coccidiodes immitis o Filipinos and Blacks run the highest risk of dissemination o High incidence in male than female (9:1) except for pregnant women o causes San Joaquin Valley fever Histoplasma capsulatum o Darling’s disease/ Central Mississippi Valley Fever and Ohio Valley Fever Paracoccidiodes braziliensis o South American Blastomycosis/ Brazillian blastomycosis Penicillium marneffei o Most common cause of systemic infection in immunocompromised host in endemic region of southeast Asia o Green or Blue Green Colonies o Branching or Penicillus head • Types of Aspergillus ▪ Aspergillus niger = presence of black pepper effect on culture media ▪ Aspergillus fumigatus = most common cause of pulmonary aspergillosis ▪ Aspergillus flavus = yellow colony ▪ Aspergillus terreus = brown colony Rhodotorulla o Contaminant but considered as an opportunistic pathogen o Pink to Coral colored colonies Fusarium o Usually a contaminant but are sometimes seen as cause of mycotic eye, nail or skin infection in debilitated patient o Presence of multiseptate macroconidia appearing as sickles or canoes Pneumocystis carinii o Classified as : Fungi ; Formerly ; Parasite o Gomori methenamine silver is stain of choice for cyst but not trophozoite o It shows cup shaped cyst and cannot be cultured o Associated with pneumonia that is resistant to antibiotic MAJOR MYCOSES AND CAUSATIVE FUNGI Type Of Mycoses Superficial Cutaneous Subcutaneous OPPORTUNISTIC MYCOSES OPPORTUNISTIC MYCOSES • • • • Develops among immunocompromised host Cryptococcus neoformans o Disease is known as Torulosis European Blastomycosis o Meningitis and Pulmonary Disease o Capsule is demonstrated by india ink Candida albicans o Most common cause of fungal diseases worldwide o Can cause disease to any site o Thrush – oral infection on immunosuppressed host o Normal biota of the skin o Mucor o Seen in patients with diabetic ketoacidosis Aspergillus o Pulmonary disease o Eschar biopsy for specimen Endemic (Primary, Systemic ) Causative Fungal Agents Malassezia furfur Hortaea werneckii Trichsoporon species(beigeli) Piedraia hortai Microsporon , Trichophyton, Epidermophyton floccosum Candida albicans and other Candida species Sporothrix schenckii Phialophora verrucosa, Fonsecaea pedrosoi Fonsecaea compacta Pseudallescheria boydii Madurella mycetomatis M. grisea Exophiala, bipolaris, exserohilum & others Coccidioides immitis Histoplasma capsulatum Blastomyces dermatitidis Paraccocidioides brasiliensis Mycosis Pityriasis versicolor Tinea nigra White piedra Black piedra Dermatophytosis (Ringworm inf.) Candidiasis of skin, mucosa or nails Sporotrichosis Chromoblastomycosis Mycetoma Phaeohyphomycosis Coccidioidomycosis Histoplasmosis Blastomycosis Paracoccidiodomycosis Type Of Mycoses Opportunistic Causative Fungal Agents Candida albicans & other Candida species Cryptococcus neoformans Aspergillus fumigatus & other Aspergillus species Species of Rhizopus, absidia, mucor and zygomycetes Penicillium marneffei Mycosis Systemic candidiasis Cryptococcosis Aspergillosis Mucormycosis/ Zygomycosis Penicilliosis SUPERFICIAL FUNGAL INFECTIONS Pityriasis versicolor • • • chronic superficial fungal infection which leads to hypopigmented or hyperpigmented patches on the skin with sunlight exposure the skin around the patches will tan, but patches will remain white caused by Malassezia furfur • Hortaea werneckii • • • is a dematiaceous fungus that produces yeast-like cells that may be one- or twocelled. E. werneckii microscopically appears as dark, 1-2 celled blastoconidia Conidia produced by this organism are produced by annellophores, which bear successive rings (annellides) Piedra hortae • • • Are difficult to see microscopically. The biophysical profile is used to differentiate this fungus from other Exophiala species. In contrast, Piedraia hortae usually does not sporulate on routine mycologic media but demonstrates only highly septate dematiaceous hyphae and swollen intercalary cells. Macroscopically they are slow growing, small, folded, velvety and dark brown to black in color. They may remain glabrous or covered with short aerial hyphae. Tinea nigra • • Dermatophytes a superficial fungal infection that causes dark brown to black painless patches on the soles of the hands and feet caused by Exophiala werneckii • PIEDRA • • • • nodular infection of the hair shaft axillary, pubic, beard and scalp hair maybe infected Black Piedra – caused by Piedraia hortai White Piedra – caused by Trichsoporon beigelii The dermatophytes, which infect only the skin, hair, or nails, secrete extracellular enzymes that likely aid in the colonization of keratinous tissues. These extracellular enzymes associated with virulence include keratinase, elastase, and lipase. CUTANEOUS FUNGAL INFECTIONS DERMATOPHYTOSES • • a caused by dermatophytes which includes: Microsporum, Trichophyton, Epidermophyton are a category of cutaneous fungal infections caused by more than 30 species of fungi are associated with infections of the skin, hair and nails Site affected Type of ringworm Head Tinea capitis, Tinea favosa Beard Tinea barbae Body Tinea corporis (glabrous skin), Tinea imbricate (lesion) Hand Tinea manuum Nails Tinea unguium Groin Tinea cruris Feet Tinea pedis • INFECTION OF THE SKIN Malassezia furfur • • • The appearance is said to be like "spaghetti and meatballs“ hyphae filaments. Malassezia species are difficult to grow in the laboratory so scrapings may be reported as "culture negative". The yeast grows best if a lipid such as olive oil is added to Littman agar culture medium. Tinea corporis o following invasion of the horny layer of the skin, the fungi spread, forming a ring shape with a red, raised border. The expanding raised red border represents areas of active inflammation with a healing center o usually caused by Trichophyton rubrum • • Tinea cruris o patient develops itchy red patches on the groin and scrotum o caused by Epidermophyton floccosum Tinea pedis o commonly begins between the toes, causes cracking & peeling of the skin o usually caused by T. mentagrophytes T. rubrum, E. floccosum INFECTION OF THE NAIL • Tinea unguium o infection typically begins at the edge of the nail. o nails are thickened, discolored and brittle o usually caused by T. mentagrophytes, • INFECTION OF THE HAIR • • Tinea capitis o characterized by scaly red lesions with loss of hair o usually caused by Microsporum canis o Microsporum audouinii & Microsporum ferrugineum ▪ Gray Patch Ringworm - Childhood disease (easily spread)olonizes outer portion of hair shafts (ECTOTRIX hair involvement) ▪ Lesions are seldom inflamed but luster & color may be lost o Trichophyton tonsurans and Trychophyton violaceum ▪ Black Dot Ringworm ▪ Endotrix hair involvement (hair follicle is the initial site → hair shaft → weakened, brittle hair → black dot stubs Tinea Favosa/ Favus o Trichophyton schoenleinii ▪ Infection of the hair follicle progressing to a crusty lesion made up of dead epithelial cells & fungal mycelia ▪ Scutula (crusty, cup-shaped flakes) are formed ▪ Consequences: Hair loss and scar tissue o Trichophyton rubrum – slow-growing organism that produces a flat or heaped-up colony that is generally white-reddish with a cottony or velvety surface. o Trichophyton mentagrophyes – produces 2 distinct colonial forms: (a) downy variety recovered form patients with tinea pedis and (b) the granular variety recovered from lesions acquired by contact with animals ▪ Rapidly growing colonies may appear as white, cottony, or downy colonies to cream colored or yellow colonies that are coarsely granular to powdery SUBCUTANEOUS FUNGAL INFECTION Sporotrichosis • • • • dimorphic fungi; H –flowerette Y-budding cigar shaped an occupational hazard for gardeners begins with a subcutaneous nodule which later on becomes necrotic and ulcerates. The ulcer heals, but new nodules pop up nearby and along the lymphatic tracts up the arm caused by Sporothrix schenckii Chromoblastomycosi • • • • • • flask shaped phiallides w/collarette; blastoconidia ( P. verrucosa and C.carrionii ) a subcutaneous infection caused by a variety of copper colored soil saprophytes-sclerotic bodies Initially a small, violet wart like lesion develops. Over months to years additional violet colored wartlike lesions arise nearby. Clusters of these lesions resemble “ cauliflower”. Skin scrapings with KOH reveals coppered colored sclerotic bodies Mycetoma • • chronic granulomatous infection of the cutaneous and subcutaneous tissue and bone characterized by tumor like deformities of the subcutaneous tissue with abscesses, draining sinuses and granulomatous pus Pseudoallescheria boydii Phaeohyphomycosis Coccidioides immitis • Exophiala jeansemi • • Mechanism of Disease o Acquired by inhalation of spores o Never transmitted from person to person o Once spores are inhaled. Localized lung infection develops followed by bloodstream dissemination Clinical Presentations o Asymptomatic o Pneumonia ( fever, cough and chest x-ray infiltrates o Disseminated ( meningitis, bone lytic granulomas, skin granulomas that break down into ulcers & other organ lesions. Diagnosis o Bronchoscopic biopsy of lung lesions, skin biopsy o Tissue can be examined with silver stain for yeast o Tissue can be grown on SDA o Serologic tests ( Complement fixation, Latex agglutination Histoplasma capsulatum • • • SYSTEMIC FUNGAL INFECTIONS • • • • • Microscopic Appearance o Mycelial Phase ▪ Coarse, septate, branched hyphae that produce thick walled barrel shaped , rectangular arthroconidia that alternate with empty disjuncter cells o Yeast Phase ▪ Large, round, thick walled spherules with endospores observed in tissue and direct examination Microscopic Appearance o Mycelial Phase ▪ Septate hyphae with round piriform microconidia on short branches or directly on hyphal stalk; later large round, thick walled knobby tuberculate macroconidia forms o Histoplasma capsulatum, Blastomyces dermatitidis and Coccidioides immits All 3 are dimorphic fungi Grows as mycelial forms with spores at 25 degC on SDA At 37 degC on BAP they grow as yeast form Natural habitat is the soil Yeast Phase ▪ Small budding, round to oval yeast cells; intra cellular to mononuclear cells, possible with Giemsa or Wright’s stain Blastomyces dermatitidis Paracoccidioides brasiliensis • • Microscopic Appearance o Mycelial Phase ▪ Septate hyphae with round or pyriform conidia borne singly on conidiophores or directly on hyphae, resembling lollipops • • • • o Yeast Phase ▪ Thick walled, large yeast cells with single bud on a broad base Specimens can be cultured in the laboratory or else slides can be directly examined under the microscope after special staining procedures. Yeast - with multiple buds resembling a mariner’s wheel Mycelia - with terminal chlamydoconidia Microscopic appearance Yeast Phase - large round to oval thick walled yeast cells with multiple buds w/c attach to mother cell by narrow constrictions Penicillium marneffei • • • • Causes penicilliosis On direct examination, appears as oval yeast cells ( resembling Histoplasma ) within histiocytes Grows as a Penicillium mold at 25 degC as bluish green, powdery, velvety colonies Mycelial phase is observed as septate hyphae with brushlike conidiophores • OPPORTUNISTIC FUNGI • Cryptococcus neoformans • • • • • A yeast characterized by a thick polysaccharide capsule Found in nature especially in pigeon droppings Causes Cryptococcosis Key to diagnosis is doing a lumbar puncture & analyzing CSF ( india ink stain) ; cryptococcal antigen test ; culture will confirm diagnosis Zygomycetes • • • • • • Candida albicans • • • • • • • • a normal flora of the GIT and mucocutaneous areas In direct microscopic examination , it appears as budding yeast with blastoconidia or pseudohyphae with no signs of constriction Gram Positive Grows readily on BAP and SDA ; colonies on EMB are with spiderlike projections The only yeast that produces germ tube when incubated with sterile serum for 1-3 hours at 35-37degC Causes Oral thrush, vaginitis and diaper rash in normal hosts In immunocompromised patients it can cause esophagitis and disseminated infection Diagnosis is made with KOH preparation of skin scrapings or with stains and cultures of biopsied tissue or blood Diaper rash o Warm moist red on the areas of diaperis o In adults, between skin folds Keratits o An inflammation of the cornea (clear, fron part of the eye) and is often caused by an infection Chronic Mucocutaneous Candidiasis o Hereditary immunodeficiency disorder is persistent or recurring infection with Candida (a fungus) due to malfunction of T cells (lymphocytes) • found on decaying vegetation and in the soil Common laboratory contaminants Causes zygomycosis – acquired through inhalation of spores Should be suspected if branching, ribbon like, non-septate hyphae are observed on direct microscopic Examination Grows as fluffy white to gray molds with brown hyphae that can cover agar surface in 1-4 days. Coarse hyphae with brown or black spores are observed microscopically Includes the genera Rhizopus, Mucor and Absidia Aspergillus • • • • • A common laboratory contaminant, found in soil and on decaying vegetation and may colonize grains, leaves or plants Causes aspergillosis, acquired through inhalation of the conidia in dust or through direct, cutaneous inoculation Aspergillus species : (1) A.fumigatus – white to blue-green (2) A. niger –black (3) A. flavus – yellow to green (4) A. terreus – tan to cinnamon (1) A.fumigatus – white to blue-green to gray (2) A. niger – yellow to black (3) A. flavus – yellow to green to brown (4) A. terreus – green to yellow Pneumocystis carinii • •