[MCR] F.02 SUPERFICIAL, CUTANEOUS AND SUBCUTANEOUS MYCOSES.pdf

PCC SOM 2026 MICROBIOLOGY F.02 SUPERFICIAL, CUTANEOUS AND SUBCUTANEOUS MYCOSES MICROBIOLOGY LECTURE LECTURER: ARLENE L. QUITASOL, MD, FPSP DATE: MAY 6,2024 TOPIC OUTLINE Superficial Mycoses A. Pityriasis Versicolor B. Tinea Nigra C. Piedra (Black and White) Cutaneous Mycoses A. Dermatophytosis Micro...

PCC SOM 2026 MICROBIOLOGY F.02 SUPERFICIAL, CUTANEOUS AND SUBCUTANEOUS MYCOSES MICROBIOLOGY LECTURE LECTURER: ARLENE L. QUITASOL, MD, FPSP DATE: MAY 6,2024 TOPIC OUTLINE Superficial Mycoses A. Pityriasis Versicolor B. Tinea Nigra C. Piedra (Black and White) Cutaneous Mycoses A. Dermatophytosis Microsporum spp. Trichophyton spp. Epidermophyton floccosum a. Tinea Pedis b. Tinea Unguium c. Tinea Corporis, Tinea Cruris & Tinea Manus Subcutaneous Mycoses A. Sporotrichosis B. Chromoblastomycosis C. Phaohyphomycosis D. Mycetoma INTRODUCTION SUPERFICIAL MYCOSES - Infections that involve the outer epithelial layers of the skinn and top layers of the hair and nails CUTANEOUS MYCOSES - Involve deeper layers of the skin and more tissue DERMATOPHYTE - Term used to group the various fungi that cause infections (dermatophytoses) of the skin, hair, and nails - Keratinophilic (i.e., able to metabolize keratin) - Three genera o Trichophyton: Infects nails, hair, and skin o Epidermophyton: Infects skin and nails o Microsporum: Infects hair and skin NOTE TAKER: BALDOS | FERRER | PADAYAO SUPERFICIAL MYCOSES PITYRIASIS VERSICOLOR Highly prevalent, chronic superficial infection of the stratum corneum Caused by species of the lipophilic yeast, Malassezia These yeasts can be isolated from normal skin and scalp and are considered part of the cutaneous mycobiota 14 currently recognized species of Malassezia Vast majority of cases of pityriasis versicolor are caused by: o Malassezia globosa o Malassezia furfur o Malassezia sympodialis Discrete, serpentine, hyper-, or hypopigmented maculae that develop on the skin, usually on the chest, upper back, arms, or abdomen Patches of discolored skin may enlarge and coalesce Scaling, inflammation, and irritation are minimal Largely a cosmetic problem Affects all ages, and the annual incidence is reportedly 5-8% Predisposing conditions include: o Immune status of the patient o Genetic factors o Elevated temperature and humidity - There may be an association between the disease and excessive sweating Most species of Malassezia require lipid in the medium for growth Diagnosis: o Confirmed by direct KOH microscopic examination of scrapings of infected skin o Clusters of thick-walled round budding yeast-like cells and short septate hyphae (spaghetti and meatballs appearance) Skin scrapings from a lesion of Pityriasis versicolor. The yeast and short hyphal forms (spaghetti and meatballs appearance) are characteristic of Malassezia furfur species complex. (Lactophenol cotton blue stain, 400x) Page 1 | 11 PCC SOM 2026 MICROBIOLOGY F.02 SUPERFICIAL, CUTANEOUS AND SUBCUTANEOUS MYCOSES TREATMENT Daily applications of selenium sulfide Topical or oral azoles Goal of treatment is not to eradicate Malassezia from the skin but to reduce the cutaneous population to commensal level TINEA NIGRA Superficial chronic and asymptomatic infection of the stratum corneum Caused by the dematiaceous fungus Hortaea (Exophiala) werneckii More prevalent in warm coastal regions and among young women Lesions appear as a dark (brown to black) discoloration, often on the palm Microscopic examination of skin scrapings from the periphery of the lesion o Presence of numerous light brown, frequently branching septate hyphae and budding cells (some with septates) on KOH preparations is suggestive of infection Piedra. (Left) White piedra hair with nodule due to growth of Trichosporon. 200×. (Right) Black piedra hair with a hard, black nodule, caused by growth of the dematiaceous mold, Piedraia hortae. 200×. Tinea Nigra TREATMENT Keratolytic solutions Salicylic acid Azole antifungal drugs PIEDRA A. BLACK PIEDRA - Nodular infection of the hair shaft caused by Piedraia hortae B. WHITE PIEDRA - Infection with Trichosporon species - Presents as larger, softer, yellowish nodules on the hairs PIEDRA Hair of the axilla, genitalia, beard, and scalp hair may be infected Endemic in tropical countries Treatment for both types o Removal of the infected hair o Application of a topical antifungal agent NOTE TAKER: BALDOS | FERRER | PADAYAO CUTANEOUS MYCOSES DERMATOPHYTOSIS Cutaneous mycoses are caused by fungi that infect only the keratinized tissue (skin, hair, and nails) Most important of these are the dermatophytes, a group of about 40 related fungi that belong to three genera: o Microsporum o Trichophyton o Epidermophyton Restricted to the nonviable skin because most are unable to grow at 37°C or in the presence of serum Among the most prevalent infections in the world Can be persistent and troublesome, they are rarely debilitating or life-threatening Dermatophyte (ringworm) infections have been recognized since antiquity Page 2 | 11 PCC SOM 2026 MICROBIOLOGY F.02 SUPERFICIAL, CUTANEOUS AND SUBCUTANEOUS MYCOSES SKIN - Diagnosed by the presence of hyaline, septate, branching hyphae, or chains of arthroconidia CULTURE - Many species are closely related and often difficult to identify. ▪ Despite their similarities in morphology, nutritional requirements, surface antigens, and other features, many species have particular keratinases, elastases, and other enzymes that enable them to be quite host-specific ▪ Identification of closely related and outbreak strains has been greatly aided by DNA sequence analysis Dermatophytosis cont’d… Acquired by contact with contaminated soil or with infected animals or humans Species are classified as: o Geophilic o Zoophilic o Anthropophilic Depending on whether their usual habitat is soil, animals, or humans ANTHROPOPHILIC SPECIES Cause the greatest number of human infections Elicit relatively mild and chronic infections Produce few conidia in culture Difficult to eradicate GEOPHILIC AND ZOOPHILIC DERMATOPHYTES Less adapted to human hosts Produce more acute inflammatory infections Tend to resolve more quickly Dermatophytosis cont’d… Some anthropophilic species are geographically restricted Globally distributed: o E. floccosum o Trichophyton mentagrophytes var. interdigitale o Trichophyton rubrum o Trichophyton tonsurans Microsporum gypseum Most common geophilic species causing human infections MORPHOLOGY AND IDENTIFICATION More common dermatophytes are identified by their colonial appearance and microscopic morphology after growth for 2 weeks at 25°C on SDA Trichophyton species May infect hair, skin, or nails Develop cylindric, smooth-walled macroconidia and characteristic microconidia Depending on the variety, colonies of T. mentagrophytes may be cottony to granular Display abundant grape-like clusters of spherical microconidia on terminal branches Coiled or spiral hyphae are commonly found in primary isolates A. Trichophyton rubrum - Colony has a white, cottony surface and a deep red, non-diffusible pigment when viewed from the reverse side of the colony. - Microconidia are small and piriform (pear-shaped) B. Trychophyton tonsurans - Produces a flat, powdery to velvety colony on the obverse surface that becomes reddish brown on reverse - Microconidia are mostly elongate Trichophyton rubrum Macroscopic Morphology - ON SDA: o Surface color: Flat to slightly raised, white to cream o Reverse color: Pink-red to red-wine Microscopic Morphology - LPCB mount: o Microconidia predominant o Club-shaped or teardrop-shaped in rows Cosmopolitan zoophilic species (and their natural hosts) include: o Microsporum canis (dogs and cats) o Microsporum gallinae (fowl) o Microsporum nanum (pigs) o Trichophyton equinum (horses) o Trichophyton verrucosum (cattle) NOTE TAKER: BALDOS | FERRER | PADAYAO Page 3 | 11 PCC SOM 2026 MICROBIOLOGY F.02 SUPERFICIAL, CUTANEOUS AND SUBCUTANEOUS MYCOSES Trichophyton mentagrophytes Macroscopic Morphology - ON SDA: o Surface color: Cream to buff colonies o Reverse color: Orange-brown to red-brown Microscopic Morphology - LPCB mount: o Microconidia predominant: Round, small clusters or along hyphae; spiral hyphae often present o Macroconidia rare: 3-8 celled, smooth, thin-walled, pencil-shaped Microsporum species Tend to produce distinctive multicellular macroconidia with echinulate walls Both types of conidia are born singly in these genera Microsporum species infect only hair and skin A. Microsporum canis - Forms a colony with a white cottony surface and a deep yellow color on reverse - Thick-walled, 8- to 15-celled macroconidia frequently have curved or hooked tips B. Microsporum gypseum - Produces a tan, powdery colony and abundant thinwalled, four- to six-celled macroconidia Microsporum gypsum Macroscopic Morphology - Flat suede-like, deep cream to cinnamon-tan Microscopic Morphology - Macroconidia predominant: Thin-walled, 4-6 cells, slightly rounded terminal ends - Rare microconidia Epidermophyton floccosum Only pathogen in this genus Produces only macroconidia, which are smooth-walled, clavate, two- to four-celled, and formed in small clusters Colonies are usually flat and velvety with a tan to olivegreen tinge Infects the skin and nails but not the hair Atypical isolates can usually be identified by speciesspecific polymerase chain reaction (PCR) tests Epidermophyton floccosum Macroscopic Morphology - ON SDA: greenish-brown or khaki-colored Microscopic Morphology - LPCB mount: Macroconidia only – club-shaped with blunt tip, often in clusters “Beaver tail” - No microconidia formed Microsporum canis Macroscopic Morphology - ON SDA: o Surface color: white to cream o Reverse color: golden yellow Microscopic Morphology - LPCB mount: o Macroconidia are typically spindle-shaped with 5-15 cells, verrucose, thick-walled and often have a terminal knob. A few pyriform to clavate microconidia are also present Genus Epidermophyton Microsporum spp. Trichophyton spp. Macroconidia Present Many Rare Microconidia None Rare Many EPIDEMIOLOGY AND IMMUNITY Dermatophyte infections begin in the skin after trauma and contact NOTE TAKER: BALDOS | FERRER | PADAYAO Page 4 | 11 PCC SOM 2026 MICROBIOLOGY F.02 SUPERFICIAL, CUTANEOUS AND SUBCUTANEOUS MYCOSES Host susceptibility may be enhanced by: o Moisture o Warmth o Specific skin chemistry o Composition of sebum and perspiration o Youth o Heavy exposure o Genetic predisposition Incidence is higher in hot, humid climates and under crowded living conditions. Shoes provide warmth and moisture, a setting for infections of the feet Anthropophilic species may be transmitted by direct contact or through fomites Dermatophytes are contagious and frequently transmitted by exposure to shed skin scales, nails, or hair containing hyphae or conidia. Fungal elements can remain viable for long periods on fomites CLINICAL FINDINGS RINGWORM OR TINEA - The clinical forms are based on the site of involvement - A single species is able to cause more than one type of clinical infection - Conversely, a single clinical form, such as tinea corporis, may be caused by more than one dermatophyte species - Very rarely, immunocompromised patients may develop systemic infection by a dermatophyte TINEA PEDIS (ATHLETE’S FOOT) Most prevalent of all dermatophytosis Usually occurs as a chronic infection of the toe webs Other varieties are: o Vesicular o Ulcerative o Moccasin types, with hyperkeratosis of the sole Initially, there is itching between the toes and the development of small vesicles that rupture and discharge a thin fluid Skin of the toe webs becomes macerated and peels, whereupon cracks appear that are prone to develop secondary bacterial infection When becomes chronic, peeling and cracking of the skin are the principal manifestations, accompanied by pain and pruritus TINEA UNGUIUM (ONYCHOMYCOSIS) Nail infection may follow prolonged tinea pedis With hyphal invasion, the nails become yellow, brittle, thickened, and crumbly One or more nails of the feet or hands may be involved Tinea Unguium TINEA CORPORIS, TINEA CRURIS, AND TINEA MANUS Dermatophytosis of the glabrous skin commonly gives rise to the annular lesions of ringworm, with a clearing, scaly center surrounded by a red advancing border that may be dry or vesicular Dermatophyte grows only within dead, keratinized tissue, but fungal metabolites, enzymes, and antigens diffuse through the viable layers of the epidermis to cause erythema, vesicle formation, and pruritus As hyphae age, they often form chains of arthroconidia Lesions expand centrifugally, and active hyphal growth occurs at the periphery, which is the most likely region from which to obtain material for diagnosis Penetration into the newly forming stratum corneum of the thicker plantar and palmar surfaces accounts for the persistent infections at those sites Tinea Corporis Tinea Cruris TINEA CRURIS (JOCK ITCH) Infection occurs in the groin area Involve males Present as dry, itchy lesions that often start on the scrotum and spread to the groin TINEA MANUS Ringworm of the hands or fingers Dry scaly lesions may involve one or both hands, single fingers, or two or more fingers Tinea Pedis NOTE TAKER: BALDOS | FERRER | PADAYAO Page 5 | 11 PCC SOM 2026 MICROBIOLOGY F.02 SUPERFICIAL, CUTANEOUS AND SUBCUTANEOUS MYCOSES TINEA CAPITIS and TINEA BARBAE Dermatophytosis or ringworm of the scalp and hair Infection begins with hyphal invasion of the skin of the scalp, with subsequent spread down the keratinized wall of the hair follicle Infection of the hair takes place just above the hair root Hyphae grow downward on the nonliving portion of the hair and at the same rate as the hair grows upward Produces dull gray, circular patches of alopecia, scaling, and itching Tinea Capitis As the hair grows out of the follicle, the hyphae of Microsporum species produce a chain of spores that form a sheath around the hair shaft (ECTOTHRIX) T. tonsurans - Chief cause of “black dot” tinea capitis - Produces spores within the hair shaft (ENDOTHRIX) - Hairs do not fluoresce; they are weakened and typically break easily at the follicular opening. In prepubescent children, epidemic tinea capitis is usually self-limiting TREATMENT Removal of infected and dead epithelial structures and application of a topical antifungal drug To prevent reinfection the area should be kept dry, and sources of infection, such as an infected pet or shared bathing facilities, should be avoided Scalp (tinea capitis) infections are treated for several weeks with oral administration of griseofulvin or terbinafine Frequent shampoos and miconazole cream or other topical antifungal agents may be effective if used for weeks For Tinea corporis, Tinea pedis, and related infections, the most effective drugs are itraconazole and terbinafine However, a number of topical preparations may be used, such as miconazole nitrate, tolnaftate, and clotrimazole. If applied for at least 2–4 weeks, the cure rates are usually 70–100% Treatment should be continued for 1–2 weeks after clearing of the lesions For troublesome cases, a short course of oral griseofulvin can be administered Nail infections (Tinea unguium) are the most difficult to treat, often requiring months of oral itraconazole or terbinafine as well as surgical removal of the nail. Relapses are common A new topical imidazole, luliconazole, has been formulated to penetrate the nail plate and demonstrated potent effectiveness against dermatophytes and onychomycosis SUBCUTANEOUS MYCOSES DIAGNOSTIC LABORATORY TESTS A. Specimens and Microscopic Examination - Specimens consist of scrapings from both the skin and the nails plus hairs plucked from involved areas - In KOH preps of skin or nails, branching hyphae or chains of arthroconidia (arthrospores) are seen B. Culture - Specimens are inoculated onto IMA or SDA slants containing cycloheximide and chloramphenicol to suppress mold and bacterial growth, incubated for 1–3 weeks at room temperature, and further examined in slide cultures if necessary - Species are identified on the basis of: ▪ Colonial morphology (growth rate, surface texture, and any pigmentation) ▪ Microscopic morphology (macroconidia, microconidia) ▪ Nutritional requirements NOTE TAKER: BALDOS | FERRER | PADAYAO Normally reside in soil or on vegetation Enter the skin or subcutaneous tissue by traumatic inoculation with contaminated material Lesions become granulomatous and expand slowly from the area of implantation Extension via the lymphatics draining the lesion is slow except in sporotrichosis Usually confined to the subcutaneous tissues, but in rare cases they become systemic and produce life-threatening disease SPOROTRICHOSIS (Rose gardeners’ disease) Sporothrix schenckii Thermally dimorphic fungus that lives on vegetation Associated with a variety of plants—grasses, trees, sphagnum moss, rose bushes, and other horticultural plants At ambient temperatures, it grows as a mold, producing branching, septate hyphae and conidia, and in tissue or in vitro at 35–37°C as a small budding yeast Page 6 | 11 PCC SOM 2026 MICROBIOLOGY F.02 SUPERFICIAL, CUTANEOUS AND SUBCUTANEOUS MYCOSES Initial episode is typically followed by secondary spread with involvement of the draining lymphatics and lymph nodes Two less common agents of sporotrichosis were recently identified: o Sporothrix brasiliensis - associated with animals o Sporothrix globose – nonlymphangitic MORPHOLOGY AND IDENTIFICATION Grows well on routine agar media At room temperature the young colonies are blackish and shiny, becoming wrinkled and fuzzy with age Strains vary in pigmentation from shades of black and gray to whitish Organism produces branching, septate hyphae, and distinctive small (3–5 μm) conidia, delicately clustered at the ends of tapering conidiophores Isolates may also form larger conidia directly from the hyphae S. schenckii is thermally dimorphic, and at 35°C on a rich medium it converts to growth as small, often multiply budding yeast cells that are variable in shape but often fusiform (about 1–3 × 3–10 μm) Draining lymphatics become thickened and cord-like Multiple subcutaneous nodules and abscesses occur along the lymphatics DIAGNOSTIC LABORATORY TESTS A. Specimens and Microscopic Examination - Specimen: biopsy material or exudate from granulomatous or ulcerative lesions - Sensitivity of histopathologic sections is enhanced with routine fungal cell wall stains ▪ Gomori methenamine silver, which stains the cell walls black ▪ Periodic-Acid-Schiff stain, which imparts a red color to the cell walls ▪ Alternatively, they can be identified by fluorescent antibody staining. The yeasts are 3–5 μm in diameter and spherical to elongated - ASTEROID BODY ▪ Often seen in tissue, particularly in endemic areas, such as Mexico, South Africa, and Japan ▪ Consists of a central basophilic yeast cell surrounded by radiating extensions of eosinophilic material, which are depositions of antigen–antibody complexes and complement B. Culture - Most reliable method of diagnosis is culture. - Specimens are streaked on IMA or SDA containing antibacterial antibiotics and incubated at 25–30°C - Identification is confirmed by growth at 35°C Sporotrichosis. Cutaneous tissue revealing the small spherical and elongated budding yeast cells (3–5 μm) of Sporothrix schenckii, which are stained black by the Gomori methenamine silver (GMS) stain. 400×. PATHOGENESIS AND CLINICAL FINDINGS Conidia or hyphal fragments of S. schenckii are introduced into the skin by trauma Initial lesion is usually located on the extremities but can be found anywhere (children often present with facial lesions) About 75% of cases are lymphocutaneous; that is, the initial lesion develops as a granulomatous nodule that may progress to form a necrotic or ulcerative lesion NOTE TAKER: BALDOS | FERRER | PADAYAO TREATMENT In some cases, the infection is self-limited. Although the oral administration of saturated solution of potassium iodide in milk is quite effective, it is difficult for many patients to tolerate. Treatment of choice: oral itraconazole or another azole For systemic disease, amphotericin B is given EPIDEMIOLOGY AND CONTROL S. schenckii occurs worldwide in close association with plants About 75% of cases occur in males, either because of increased exposure or because of an X-linked difference in susceptibility Incidence is higher among agricultural workers Page 7 | 11 PCC SOM 2026 MICROBIOLOGY F.02 SUPERFICIAL, CUTANEOUS AND SUBCUTANEOUS MYCOSES Prevention includes measures to minimize accidental inoculation and the use of fungicides, where appropriate, to treat wood CHROMOBLASTOMYCOSIS Subcutaneous mycotic infection that is usually caused by traumatic inoculation of any of the recognized fungal agents, which reside in soil and vegetation All are dematiaceous fungi, having melanized cell walls: A. Phialophora verrucosa B. Fonsecaea pedrosoi C. Fonsecaea compacta D. Rhinocladiella aquaspersa E. Cladophialophora carrionii Infection is chronic and characterized by the slow development of progressive granulomatous lesions that in time induce hyperplasia of the epidermal tissue MORPHOLOGY AND IDENTIFICATION Colonies are compact, deep brown to black, and develop a velvety, often wrinkled surface. Agents of chromoblastomycosis are identified by their modes of conidiation. In tissue they appear the same, producing spherical brown cells (4–12 μm in diameter) termed MURIFORM or SCLEROTIC BODIES that divide by transverse septation Septation in different planes with delayed separation may give rise to a cluster of four to eight cells Cells within superficial crusts or exudates may germinate into septate, branching hyphae Chromomycosis. The diagnostic brownish, melanized sclerotic cells (4–12 μm diameter) are evident in this H&E stained cutaneous biopsy. 400×. Phialophora verrucosa Macroscopic Morphology Olivaceous to black, suede-like colony Microscopic Morphology - Flask-shaped or elliptical phialides with distinctive funnel-shaped, darkly pigmented collarattes Fonsecaea species complex F. monophora, F. nubica, and F. pedrosoi All strains will grow at 37°C but not at 40°C Macroscopic Morphology - Olivaceous to black, with black reverse, flat to heaped and folded, suede-like to downy Microscopic Morphology - Septate, dark brown hyphae and conidiophores that highly branch at apex suberect Cladophialophora carrionii Macroscopic Morphology - Olivaceous to black, suede-like to downy surface Microscopic Morphology - Ascending to erect, olivaceous-green, apically branched, elongate conidiophores producing branched acropetal chains of conidia PATHOGENESIS AND CLINICAL FINDINGS Introduced into the skin by trauma, often of the exposed legs or feet Over months to years, the primary lesion becomes verrucous and wart-like with extension along the draining lymphatics Cauliflower-like nodules with crusting abscesses eventually cover the area Small ulcerations or “black dots” of hemopurulent material are present on the warty surface Histologically, the lesions are granulomatous, and the dark sclerotic bodies may be seen within leukocytes or giant cells DIAGNOSTIC LABORATORY TESTS Specimens of scrapings or biopsies from lesions are examined microscopically in KOH for dark, spherical cells NOTE TAKER: BALDOS | FERRER | PADAYAO Page 8 | 11 PCC SOM 2026 MICROBIOLOGY F.02 SUPERFICIAL, CUTANEOUS AND SUBCUTANEOUS MYCOSES Detection of the sclerotic bodies is diagnostic of chromoblastomycosis regardless of the etiologic agent Tissue sections reveal granulomas and extensive hyperplasia of the dermal tissue Specimens should be cultured on IMA or SDA with antibiotics The dematiaceous species is identified by its characteristic conidial structures TREATMENT Surgical excision with wide margins is the therapy of choice for small lesions Chemotherapy with flucytosine or itraconazole may be efficacious for larger lesions The application of local heat is also beneficial EPIDEMIOLOGY Occurs mainly in the tropics. Saprophytic in nature Occurs chiefly on the legs of barefoot agrarian workers following traumatic introduction of the fungus Not communicable Wearing shoes and protecting the legs probably would prevent infection PHAEOHYPHOMYCOSIS Term applied to infections characterized by the presence of darkly pigmented septate hyphae in tissue Both cutaneous and systemic infections have been described Clinical forms vary from solitary encapsulated cysts in the subcutaneous tissue to sinusitis to brain abscesses Over 100 species of dematiaceous molds have been associated with various types of phaeohyphomycotic infections All exogenous molds that normally exist in nature. Some of the more common causes of subcutaneous phaeohyphomycosis are: o Exophiala jeanselmei o Phialophora richardsiae o Bipolaris spicifera o Wangiella dermatitidis In tissue, the hyphae are large (5–10 μm in diameter), often distorted and may be accompanied by yeast cells, but these structures can be differentiated from other fungi by the melanin in their cell walls Specimens are cultured on routine fungal media to identify the etiologic agent In general, itraconazole or flucytosine is the drug of choice for subcutaneous phaeohyphomycosis Brain abscesses are usually fatal, but when recognized, they are managed with amphotericin B and surgery. Leading cause of cerebral phaeohyphomycosis is Cladophialophora bantiana NOTE TAKER: BALDOS | FERRER | PADAYAO Phaeohyphomycosis Chronic subcutaneous lesions Does not produce sclerotic bodies Mycelial form MYCETOMA Chronic subcutaneous infection induced by traumatic inoculation with any of several saprophytic species of fungi or actinomycetous bacteria that are normally found in soil Natural history and clinical features of both types of mycetoma are similar, but actinomycetomas may be more invasive, spreading from the subcutaneous tissue to the underlying muscle CLINICAL FEATURES Local swelling of the infected tissue Interconnecting, often draining, sinuses or fistulae that contain granules, which are microcolonies of the agent embedded in tissue material 1. 2. ACTINOMYCETOMA mycetoma caused by an actinomycete EUMYCETOMA (MADUROMYCOSIS, MADURA FOOT) mycetoma caused by a fungus MORPHOLOGY AND IDENTIFICATION The fungal agents of mycetoma include: o Pseudallsecheria boydii (anamorph, Scedosporium apiospermum) o Madurella mycetomatis o Madurella grisea o Exophiala jeanselmei o Acremonium falciforme In the United States, the prevalent species is P. boydii, which is self-fertile (homothallic) and has the ability to produce ascospores in culture. E. jeanselmei and the Madurella species are dematiaceous molds Page 9 | 11 PCC SOM 2026 MICROBIOLOGY F.02 SUPERFICIAL, CUTANEOUS AND SUBCUTANEOUS MYCOSES Identified primarily by their mode of conidiation In tissue, the mycetoma granules may range up to 2 mm in size The color of the granule may provide information about the agent. For example, the granules of mycetoma caused by P. boydii and A. falciforme are white; those of M. grisea and E. jeanselmei are black; and M. mycetomatis produces a dark red to black granule These granules are hard and contain intertwined, septate hyphae (3– 5 μm in width) The hyphae are typically distorted and enlarged at the periphery of the granule Eumycetoma Black granules Madurella mycetomatis Madurella grisea Exophiala jeanselmei Curvularia species White granules Pseudallsecheria boydii Aspergillus nidulans Acremmonium species Fusarium species Actinomycetoma White to yellow granules Nocardia species Streptomyces somaliensis Actinomadura madurae Pink to red granules Actinomadura pelletieri Macroscopic appearance (Eumycetoma) PATHOGENESIS AND CLINICAL FINDINGS Develops after traumatic inoculation with soil contaminated with one of the agents Subcutaneous tissues of the feet, lower extremities, hands, and exposed areas are most often involved Characterized by suppuration and abscesses, granulomata, and draining sinuses containing the granules Untreated lesions persist for years and extend deeper and peripherally, causing deformation and loss of function DIAGNOSTIC LABORATORY TESTS Granules can be dissected out from the pus or biopsy material for examination and culture on appropriate media Granule color, texture, and size and the presence of hyaline or pigmented hyphae (or bacteria) are helpful in determining the causative agent Draining mycetomas are often superinfected with Staphylococci and Streptococci TREATMENT Management is difficult, involving surgical debridement or excision and chemotherapy P. boydii is treated with topical nystatin or miconazole Itraconazole, ketoconazole, and even amphotericin B can be recommended for Madurella infections and flucytosine for E. jeanselmei Chemotherapeutic agents must be given for long periods to adequately penetrate these lesions EPIDEMIOLOGY AND CONTROL Organisms producing mycetoma occur in soil and on vegetation Barefoot farm laborers are therefore commonly exposed. Properly cleaning wounds and wearing shoes are reasonable control measures Macroscopic appearance (Actinomycetoma) CHECK POINT CATEGORIES OF MAJOR MYCOSES A. Superficial Mycoses B. Cutaneous Mycoses C. Subcutaneous Mycoses _____1. Dermatophytosis _____2. Phialophora verrucosa _____3. Malassezia species _____4. Piedraia hortae _____5. Phaehyphomycosis _____6. Involve deeper layers of skin and more tissue _____7. Involve the outer layer of skin and top layer of the hair and nails _____8. Tinea nigra _____9. Candida albicans _____10. Mycetoma NOTE TAKER: BALDOS | FERRER | PADAYAO Page 10 | 11 PCC SOM 2026 MICROBIOLOGY F.02 SUPERFICIAL, CUTANEOUS AND SUBCUTANEOUS MYCOSES DERMATOPHYTE A. Trichophyton B. Epidermophyton C. Microsporum A. B. C. D. _____11. Infects skin and nails _____12. Infects hair and skin _____13. Infects nails, hair, and skin PRESENT MANY RARE NONE Genus Trichophyton spp. Epidermophyton Microsporum spp. SUPERFICIAL MYCOSES A. Pityriasis versicolor B. Tinea nigra C. Black piedra D. White piedra A. B. C. D. Etiological Agents _____14. Malassezia furfur _____15. Trichosporons spp. _____16. Hortaea werneckii _____17. Piedraia hortae Identification of organisms _____18. Black nodule on hair shaft composed of spore sacs (asci) and spores (ascospores) _____19. Annelide formation _____20. Spaghetti and meatballs _____21. White nodule on hair shaft composed of mycelia that fragment into arthrospores CUTANEOUS MYCOSES 22. Three genera of dermatophytes, EXCEPT: A. Macrosporum B. Microsporum C. Trichophyton D. Epidermophyton Macroconidia 30 31 32 Microconidia 33 34 35 Tinea pedis Tinea cruris Tinea manus Tinea capitis _____36. Produces dull gray, circular patches of alopecia, scaling and itching _____37. Dry scalp lesions may involve one or both hands, single fingers, or two or more fingers _____38. Infection occurs in the groin area _____39. Most prevalent of all dermatophytosis 40. All are dematiaceous fungi with melanized cell walls, EXCEPT: A. Phialophora verrucosa B. Fonsecaea pedrosoi C. Rhinocladiella aquaspersa D. Cladophialophora carrionii E. NOTA 41. White to yellow granules, EXCEPT: A. Actinomadura pelletieri B. Streptomyces somaliensis C. Nocardia species D. Actinomadura madurae 23. Characteristics of Anthropophilic species, EXCEPT: A. Elicit relatively mild and chronic infections B. Difficult to eradicate C. Produce many conidia in culture D. Cause the greatest number of human infections 42. White granules, EXCEPT: A. Pseudallsecheria boydii B. Aspergillus nidulans C. Madurella grisea D. Fusarium species 24. Characteristic of geophilic and zoophilic dermatophytes A. Produce more acute inflammatory infections B. Less adapted to human hosts C. Tend to resolve more quickly D. AOTA 43. Characteristics of Phaeohyphomycosis A. Mycelial form B. Does not produce sclerotic bodies C. Chronic subcutaneous lesions D. AOTA COSMOPOLOTAN ZOOPHILIC SPECIES __25. Microsporum nanum __26. Trichophyton verrucosum __27. Microsporum canis __28. Trichophyton equinum __29. Microsporum gallinae _______________44. Consists of a central basophilic yeast cell surrounded by radiating extensions of eosinophilic material, which are depositions of AG-Ab complexes and complement A. Dogs and cats B. Fowl C. Horses D. Pigs E. Cattle NOTE TAKER: BALDOS | FERRER | PADAYAO BCAACBAABC | BCA | ADBC | CBAD | ACD | DEACB | C A B B D C | D C B A | E A B D | Asteroid body Page 11 | 11