Mycology and Virology (MLS 415) PDF

| Topic 4 | [MLS 415] Mycology and Virology P4: Cutaneous Mycoses Professor: Thynee Tago, RMT Date: February 9, 2024 ➔ ➔ ➔ ➔ ➔ ➔ CUTANEOUS MYCOSES a.k.a. Dermatophytosis Commonly known as ringworm ◆ lesions of rashes appear in a ring-like pattern Caused by Dermatophytes Affects: (1) hair, (2) nai...

| Topic 4 | [MLS 415] Mycology and Virology P4: Cutaneous Mycoses Professor: Thynee Tago, RMT Date: February 9, 2024 ➔ ➔ ➔ ➔ ➔ ➔ CUTANEOUS MYCOSES a.k.a. Dermatophytosis Commonly known as ringworm ◆ lesions of rashes appear in a ring-like pattern Caused by Dermatophytes Affects: (1) hair, (2) nails, (3) skin Cellular immune response may be evoked With pathologic changes DERMATOMYCOSES VS. DERMATOPHYTOSIS General term Caused by other fungi Most often Candida ➔ ➔ ➔ ➔ A. DERMATOPHYTES Keratinophilic - they love keratin Produce keratinases - enzymes that can break down keratin Resistant to cycloheximide Unable to grow at 37ºC, nor in serum ◆ they are true molds; able to grow best at RT or 25 deg C ◆ serum contain growth inhibitors CLASSIFICATION OF DERMATOPHYTES ANTHROPOPHILIC ○ Present most in humans ○ Cannot be passed on from infected human to another ○ E.g. Epidermophyton & Trichophyton rubrum GEOPHILIC ○ Best survive in soil ○ E.g. Microsporum gypseum ZOOPHILIC ○ Thrives on animals (fur, skin) ○ Capable of infecting humans ○ E.g. (1) Microsporum canis (dog and cats), (2) Microsporum nanum (swine), (3) Trichophyton verrucosum (horses and swine) Species Immunity (Host Defense) Serum growth inhibitors C-type lectin receptor ○ responsible in signaling immune response ○ Signals other cells that can fight off the dermatophytes IL-17 and IFN-y ○ contribute to antidermatophytic defense and skin inflammation control Transferrin – responsible in carrying iron ○ iron is an important growth requirement for fungal elements Immunity varies in duration and degree Transmission Close human contact ○ (1) Sharing clothes, (2) combs, brushes, (4) towels, (5) bedsheets Animal-to-human contact (Zoophilic) INCUBATION PERIOD: 1-2 weeks (3) CLINICAL DIAGNOSIS Appearance ➔ Woods lamp (UV, 365nm) ◆ possible for dermatophytes that are able to fluoresce ◆ usually green and blue in color; pink and purple in some Infected Parts Epidermophyton Skin, Nails Trichophyton Hair, Skin, Nails Microsporum Hair or Skin ➔ DERMATOPHYTOSIS Moisture; dermatophytes survive well in moist environment Crowded living conditions Cellular immunodeficiency ○ for immunocompetent individuals: simple, treatable infections ○ for immunosuppressed individuals: severe infections Re-infection is possible ○ shorter course ○ when introduced to a much with larger amount of inoculum Pathogenesis Acquired through (1) contact, (2) fomites & (3) trauma Dermoscopy ◆ Epiluminoscopy / Epiluminescence microscopy ◆ Can now be attached in your phones @mlstranses | 1 EPIDERMOPHYTON LABORATORY DIAGNOSIS Direct Microscopy (1) Skin & nail scraping & (2) epilated hairs 10% KOH with parker ink or Calcofluor white Observe macroconidia & microconidia Species CULTURE [L] Microconidia; [R] Macroconidia Macroconidia Microconidia Fusiform (mostly macro) + Clavate (Club-shaped) - Cylindrical/ Clavate/ Fusiform +, single, clusters; (mostly micro) Macroconidia only ○ microconidia are not produced ○ Has less macroconidia than microsporum Culture on petri dishes (Traditional) Riddel's slide culture; because they are not dimorphic fungi MICROSPORUM Microsporum Epidermophyton Trichophyton Species Appearance M. canis white cottony surface deep yellow on reverse M. gypseum tan, powdery colony yellow with orange-brown center on reverse MICROSPORUM [Left] M. canis; [Right] M. gypseum Looks like an “Ipil-Ipil” Large multicellular macroconidia 8-15 celled, thick walled macroconidia with curved or hooked tip RARELY produces microconidia Species TRICHOPHYTON T. rubrum White cottony surface Deep red,non-diffusible pigment on reverse T. tonsurans Flat, powdery to velvety colony Reddish-brown on reverse T. mentagrophytes Cottony to granular TRICHOPHYTON Appearance Predominant forms are microconidia ○ macroconidia are uncommon coiled/spiral hyphae (primary isolation) CANNOT FLUORESCE under Wood’s lamp @mlstranses | 2  CLINICAL MANIFESTATION SKIN → Circular, dry, erythematous, scaly, itchy lesions HAIR/SCALP → ”kerion”, scarring, alopecia, favus NAIL → Thickened, deformed, discolored, weak, subungual debris accumulation (Debris under your nails) CLINICAL CLASSIFICATIONS A. Tinea pedis NOTE: Older hyphae is located in the center, new hyphae is located on the edges ➔ ADDITIONAL INFORMATION: Trichophyton Agar ○ for presumptive identification of Trichophyton species based on nutritional requirements. T. rubrum no special vitamin requirement T. tonsurans and T. violaceum require thiamine T. verrucosum require thiamine & inositol MOST COMMON AGENTS ➔ T. rubrum ➔ T. mentagrophytes var interdigitale ◆ Can cause blisters ➔ E. floccosum ◆ "Moccasin-type" – affects whole plantar surface ◆ Very common in people who works bear-footed B. Tinea manuum EPIDERMOPHYTON Species E. floccosum Appearance flat, velvety; dry colonies (macroconidia) tan to olive green ATHLETE’S FOOT ◆ characterized by fissures/cracks, scales, maceration in the toe web ◆ There may also be erythema, vesicles, pustules. Physiological Tests In vitro hair perforation test ○ Specimen: epilated hair ○ Put in a petri dish with moist filter paper ○ Incubate for 2 weeks @25 deg C ○ (+) Conical hair performation Special amino acid & vitamin requirements Urea hydrolysis Growth on polished rice grains Temperature tolerance & enhancement PCR (Genomics) Ringworm of the hands Involves one hand but may occasionally be affected both hands Palms become (1) diffusely dry, (2) scaly and (3) erythematosus Most often caused by anthropophilic dermatophytes Cases may be an extension of athlete’s foot MOST COMMON AGENT: ➔ T. rubrum Other agents: ➔ E. floccosum ➔ M. canis ➔ M. gypseum ➔ T. mentagrophytes ➔ T. verrucosum @mlstranses | 3 C. Tinea cruris JOCK ITCH Infection of the groin Characterized by raised red lesions/borders ○ can spread to the inner thighs or scrotum from the groin ○ downy stain and granular stain Mostly seen on adult men, but women can also be infective Infections often come from the feet or nails MOST COMMON AGENTS ➔ E. floccosum ➔ T. rubrum Other agents ➔ M. nanum ➔ T. mentagrophytes ➔ T. raubitschekii D. Tinea unguium ONYCHOMYCOSIS ; Ringworm of the nails Characterized by thickening, discolored or dystrophic nails ○ nail plate may be separated from the nail bed MOST COMMON AGENTS ➔ T. rubrum ➔ T. mentagrophytes var mentagrophytes Other agents: ➔ E. floccosum ➔ T. tonsurans ➔ T. violaceum E. Superficial infection of the skin caused by dermatophytes Affects ANY PART of the body ○ may exclude (1) hands, (2) feet, (3) nail, (4) beard, (5) groin and (6) scalp Spread by the shedding of fungal spores from infected skin; facilitated by warm moist environment Incubation period: 1-3 weeks ○ invades and spreads in the stratum corneum but is unable to penetrate deeper layers of the skin Initially presents a solitary circular, raised red patch ○ starts with one ring and may eventually coalesce over time ○ may present central hyperpigmentations Oral treatment ○ Azole, Echinocandins ○ TERBINAFINE works similar to azoles by inhibiting ergosterol synthesis Difference: inhibits or binds to a particular enzyme involved in the ergosterol synthesis works well with itraconazole MOST COMMON AGENTS ➔ T. rubrum ➔ M. canis ➔ T. tonsurans ➔ T. verrucosum ◆ Usually associated with severe types of ringworm infection Other agents: ➔ E. floccosum ➔ M. audouinii ➔ M. gypseum ➔ T. mentagrophytes ➔ T. schoenleinii ➔ T. violaceum CLINICAL VARIANTS Kerion → A very large ulcerated lesion → inflammatory form of Tinea corporis Tinea corporis Tinea gladiatorum → the most common form → commonly found on individuals involved in contact sports Ringworm of the body or simply RINGWORM @mlstranses | 4 Tinea imbricata → characterized by extensive concentric rings → forms polycyclic plaques/ lesions with thick scales; can be all over the body → very itchy Tinea incognita → occurs after taking inappropriate treatment → Cannot be recognized; most probably because of excessive use of over the counter drug Majocchi’s granuloma → invasive type → Can infect subcutaneous → commonly found on the limbs after shaving F. Tinea barbae BARBER’S ITCH Lesions involved (1) scaling, (2) follicular pustules, and (3) erythema Caused by anthropophilic or zoophilic dermatophytes Farm workers are often affected with this type of infection. MOST COMMON AGENTS ➔ T. verrucosum Other agents: ➔ M. canis ➔ T. mentagrophytes ➔ T. rubrum ➔ T. violaceum H. Tinea capitis SCALP RINGWORM S/s: hair loss, presence of dry scaly areas, redness and itchiness Prevalent between children (3-7 years old) ○ most common in boys MOST COMMON AGENTS ➔ M. canis ➔ T. tonsurans ◆ may occur in immunocompromised adults ➔ M. audouinii Other agents: ➔ M. ferrugineum ➔ M. gypseum ➔ M. nanum ➔ M. persicolor ➔ T. mentagrophytes ➔ T. schoenleinii ➔ T. soudanense ➔ T. verrucosum ➔ T. violaceum CLINICAL VARIANTS Kerion → inflammatory type → hair loss may be permanent → presents of pustules; bleeding Dry scaly area → resembles dandruff but is accompanied by hair loss, pruritus G. Tinea faciei Black dots → broken hair Ringworm of the face Usually seen on non-bearded part of the face ○ (1) cheeks, (2) nose, (3) forehead, (4) near the (4) ears Pruritus: itching and burning sensation Lesion may resemble Tinea corporis Some may have little or no scaling, may show raised edges, or slightly discolored MOST COMMON AGENTS ➔ T. tonsurans in North America ➔ T. mentagrophytes and T. rubrum in Asia Favus → rare chronic inflammatory infection caused by shown lining → characterized by matted hair and formation of yellow crusted cap-shaped lesions → usually appears on the base of the hair → the crust contain hyphae and keratin debris @mlstranses | 5 INFECTION OF THE HAIR DUE TO TINEA CAPITIS COMPLICATIONS OF TINEA Alopecia ○ hair loss ○ can cause psychosocial distress on the patient Dermatophytid (Id reaction) ○ generalized acute cutaneous reaction ○ an allergic response to fungal antigens may create rashes in the other parts of the body apart from the infected area ○ Microscopic & culture (-) differentiates dermatophytid from actual fungal infection ○ finding of dermatophytosis elsewhere on the body ○ Trichophyton skin test (-) ADDITIONAL TESTS: Dermoscopy ○ fast, non-invasive procedure ○ useful in confirming Tinea capitis and other forms of Tinea infection ○ Dermoscopic findings with very high predictive value for Tinea capitis are the ff: comma hairs: short hairs that bend and go back into the scalp corkscrew hairs zigzag hairs barcode hairs: shorter than 1mm Following the invasion of keratinized stratum corneum of the scalp, the fungi may grow downwards into the hair follicle and shaft ENDOTHRIX → dermatophytes invades the hair shaft and grows within it ○ The hair shaft is filled with hyphae & spores (arthroconidia) cuticle is not destroyed ○ Do not fluoresce with wood's light ○ e.g. T. tonsurans, T. violaceum, T. soudanense ECTOTHRIX → dermatophytes grows within the follicle and covers the surface of the hair ○ can destroy cuticle ○ the hyphae & arthroconidia cover the outside of the hair ○ can fluoresce under Wood's light ○ e.g. M. canis, M. audouinii, M. distortum, M. ferrugineum, M. gypseum, M. nanum, T. verrucosum Blue dots are the fungal elements Treatment and Control [UPPER L TO R] Comma hair, Corkscrew hair [LOWER L TO R] Zigzag hair, Barcode hair ➔ ➔ ➔ ➔ Griseofulvin ○ Taken orally ○ Very effective Terbinafine (more recent) ○ does not fall under polyene, azoles or echinocandins ○ works similarly with azoles Inhibits production of the ergosterol Itraconazole Fluconazole Topical: ○ Povidone-iodine ○ Ketoconazole (nizoral) ○ Selenium sulfide shampoo General Procedures to Control Tinea infection Screen all members of a household Treat simultaneously if positive No sharing of personal things Have pets checked by vet @mlstranses | 6 | Topic 5 | [MLS 415] Mycology and Virology P5: Subcutaneous Mycoses Professor: Thynee Tago, RMT Date: February 17, 2024 SUBCUTANEOUS MYCOSES Chronic localized infections of the skin as well as the subcutaneous tissue Portal of entry ○ traumatic inoculation Caused by exogenous fungi that normally reside in nature ○ causative agent are all soil saprophytes whose ability to adapt to the tissue environment and cause disease is extremely variable an enzyme associated with invasiveness of the organism; can be seen when culture is incubated below 37ºC CLINICAL MANIFESTATION A. SPOROTRICHOSIS Chronic infection of the subcutaneous tissues and lymphatics A fungal infection of the skin caused by a fungus found on the decaying vegetation, rose bushes or any plants with thorns, twigs, hays, z (usually grows on moist soil) a.k.a. Rose Gardener’s Disease ○ thorn/splinter trauma hand, arm or leg Occupational hazard ○ farmers, miners, gardeners, florists Causative agent: Sporothrix schenckii ○ dimorphic fungi; temperature sensitive ○ 5 Phylogenetically distinct spp.: S. schenckii S. albicans S. brasiliensis S. globose S. mexicana ○ Report: “Sporothrix schenckii species complex.” Types (A) FIXED CUTANEOUS SPOROTRICHOSIS ○ primary lesion begins as a small, non-healing ulcer may also appear as plaques or rashes ○ common on index finger or back of the hand ○ restricted & less progressive ○ does not involve lymphatics ○ most common form ○ first symptom: small, painless bump that can develop anytime from 1-12 weeks after exposure bump my be red, pink, or purplish bum may grow larger and may ulcerate ○ if left untreated: remains in the skin 60% of untreated cases progresses into lymphocutaneous sporotrichosis Growth Fixed Cutaneous grows well at 35ºC but not at 37ºC Lymphocutaneous grows well at 35ºC and 37ºC Neuraminidase - a lymphocutaneous types virulence factor present in (B) LYMPHOCUTANEOUS SPOROTRICHOSIS ○ infections spreads along the lymph nodes and a chain of lymphatic nodules develop in a line @mlstranses | 1  ○ ○ ○ ○ usually starts on the inoculated portion and the lesion goes up the infected leg/arm small non-tender nodules that later ulcerates lymphatic vessels & LN draining the region (forearm) Chronic: multiple, hard, cord-like Red to black areas (E) DISSEMINATED SPOROTRICHOSIS ○ skin, eye, the prostate, the oral mucosa, the paranasal sinuses, and the larynx ○ clinical manifestations depend on the organs involved ○ usually affects immunocompromised individuals (C) PULMONARY SPOROTRICHOSIS ○ Rare but can happen when someone inhales fungal spores from the environment inhalation of conidia ○ Cough with sputum, fever, weight loss, upper-lobe lesion seen on xrays usually appears on the apex of the lungs but can spread out; mimics TB ○ haemoptysis may occur (coughing of blood) ○ the natural course: gradual progression to death (D) OSTEOARTICULAR SPOROTRICHOSIS ○ stiffness & pain in large joints (knee, elbow, ankle, wrist) ○ with cutaneous lesions on long bones near affected joints ○ often seen in patients with a history of alcohol abuse or immunosuppression ○ may sometimes present as chronic arthritis that is often confused with rheumatoid arthritis ○ in most cases, this may persist for about 30 or more years ○ generally begins as monoarticular arthritis (only one knee is affected; primarily the knee joint) and may eventually affect other joints ○ functional impairment may become severe in time LABORATORY DIAGNOSIS SPECIMEN ○ aspirated pus from nodules, scrapings, biopsy tissue swabs, [LEFT] mycelia form [RIGHT] yeast form DIRECT EXAMINATION: KOH or calcofluor ○ mycelia form (RT) Hyphae: narrow, septate Conidia: thin-walled pyriform arranged singly or in a flowerette ○ yeast form (37ºC) small, elliptoid, budding, cigar-shaped yeasts asteroid bodies stained with H&E [L to R] PAS, GMS, H&E TISSUE BIOPSY ○ Gomori’s Methenamine Silver: black adsorption: only the surface is covered with the stain ○ Periodic Acid Schiff: red ○ Fluorescent Antibody Testing (FAT) @mlstranses | 2 ○ H&E: asteroid bodies / Splendore-Hoeppli phenomenon inside are the antigen; outside are the structures covering the antibodies only yeast form are seen (for tissue biopsies) B. MYCETOMA CULTURE ○ rapid growing (3-5 days) ○ white, pasty, moist colony later becomes brown/ black, wrinkled or leathery ○ SDA with cycloheximide at 25-30ºC ○ inhibitory mold agar (IMA), BHI with 5% sheep’s blood ○ confirmed by growth at 35- 37ºC & conversion to yeast form OTHER PHYSIOLOGICAL TESTS ○ Phenotypic characteristics such as the morphology of sessile pigmented conidia pear-shaped, firmly attached to the hyphal structure not easily removed when teased ○ Growth at 30°C, 35°C, 37°C ○ CHO assimilation (sucrose, raffinose, ribitol) ○ Molecular sequencing using the calmodulin gene target SEROLOGY ○ Yeast Cell Agglutination Test a titer of 1:160 or greater is diagnostic of sporotrichosis ○ Sporotrichin elicits delayed skin test reactions in sensitive persons major usefulness is in epidemiological investigation Usually positive in 95% confirmed cases but can also indicate previous infection of the fungal organism Madura foot / Maduromycosis Chronic infection of the (1) skin including (2) subcutaneous tissue, and sometimes (3) muscles, (4) bones, and (5) joint Characterized by the presence of nodules ○ will eventually erupt creating sinus tract that will discharge exudates or pus ○ the pus may contain granulomatous materials Traumatic inoculation with several saprophytic fungi Primarily lesion becomes locally invasive and tumor-like ○ may also present small, subcutaneous swelling ○ sclerotia: darkened structures present on the exudates or pus Usually in lower extremities (barefoot) 2 TYPES: EUMYCETOMA ○ caused by fungal organism ○ fungal mycetoma ACTINOMYCETOMA ○ caused by filamentous bacteria coming from the order of Actinomycetes ○ bacterial mycetoma CLINICAL MANIFESTATION TREATMENT Oral itraconazole, Ketoconazole, Griseofulvin, Dihydroxysilbamidine, Flucytosine Amphotericin B (systemic) Saturated solution of KI in milk 2% KI in 0.2% iodine (surface lesions) @mlstranses | 3  Chronic infection Affected area has normal skin temperature but may be hyperpigmented → normally, there is increased heat on the affected area when there is inflammation Swelling, purplish discoloration Tumor-like deformities of subcutaneous tissue Draining sinuses and sclerotia (granules) May progress to involve bone, muscle & tissues MYCETOMA: TYPES AND AGENTS Actinomycetoma and Eumycetoma have similar clinical features; actinomycetoma tend to be more aggressive and destructive invading bones; because bacterial agents are able to grow twice or thrice or four times faster than fungal elements ACTINOMYCOTIC (bacterial) ○ Actinomycetes Actinomyces Nocardia Streptomyces ○ History & clinical features are similar but actinomycetoma is more invasive EUMYCETOMA (fungal) definitive diagnosis: demonstration of grains grains present in exudates and pus are commonly dark ○ bacterial mycetoma usually produce white or light colored grains Dark/black Grains Madurella mycetomatis Trematosphaeria grisea (prev. Madurella grisea) Exophiala jeanselmei Medicopsis romeroi Curvularia lunata A. Madurella mycetomatis Most common cause of eumycetoma WORLDWIDE Filamentous; found in soil South America, Africa, & India Reddish brown or black and granules ○ hyphae embedded in a brown, cementlike matrix No teleomorphs (sexual form) ⇒ more on anamorphs MICROSCOPIC: Septate hyphae; chlamydospores sclerotia (large and black masses of hyphae) dematiaceous and sterile under laboratory conditions MACROSCOPIC: colony growth is faster at 37°C than at 25 or 30°C growth occurs up to 40°C colonies are white initially, then becomes yellow, brown or olivaceous brown diffusible pigment may be produced glabrous to velvety, flat or heaped B. White Grains Acremonium spp. Fusarium spp. Aspergillus flavus Microsporum audouinii Scedosporium apiospermum Scedosporium boydii (prev. Pseudallescheria boydii) Scedosporium boydii (Pseudallescheria boydii) Most common agent of mycetoma in US Ascomycota group Homothallic – an organism having both male and female reproductive structures, allowing it to undergo self-fertilization. Seen in (1) soil, (2) standing water and (3) sewage Has been seen on: ○ Pseudallescheriasis ○ Meningitis, Brain abscess ○ Endocarditis S. boydii can only produce white grains ○ unlink E. jeanselmei & Madurella spp. which produces darken grains because there are dematiaceous molds primarily identified by mode of conidiation [LEFT] Madurella mycetomatis in H&E [RIGHT] Madurella grisea in H&E @mlstranses | 4 ○ [LEFT] anamorph [RIGHT] teleomorph in some cases, elephantiasis and lymphostasis van occur resulting to secondary infection AGENTS (Dematiaceous Fungi ⇒ oil & plant debris): ○ Cladosporium (C. carrionii) ○ Phialophora (P. verrucosa) ○ Fonsecaea (F. pedrosoi, F. compacta) ○ Rhinocladiella aquaspersa MICROSCOPIC Anamorph (asexual form) ○ elliptic, single-celled conidia borne singly from the tips of conidiophores Teleomorph (sexual form) ○ cleistothecia with asci & ascospores LABORATORY DIAGNOSIS SPECIMEN ○ scrapings / biopsies of lesions DIRECT MICROSCOPY → KOH CULTURE ○ SDA with or without antibiotics MACROSCOPIC rapid growing (5-10 days) initial growth: white fluffy colony old growth: brownish gray colony reverse: tan-dark brown PHYSIOLOGICAL TESTS CHO assimilation Nitrate utilization Molecular assays using targets within the rDNA complex (calmodulin gene target) ○ Reliable for ID of dematiaceous fungi like Madurella spp. TREATMENT Surgical debridement or excision Long chemotherapy S. boydii ○ topical nystatin or miconazole E. jeanselmei ○ flucytosine Madurella ○ itraconazole, ketoconazole, amphotericin B C. CHROMOBLASTOMYCOSIS a.k.a. Chromomycosis Traumatic inoculation Warty, verrucous or cauliflower-like lesions (lower extremities) ○ some may appear slightly raised May remain localized but can eventually be extensive with keloid formation Minimal discomfort; Granulomatous nodules; Epidermal hyperplasia Genetic predisposition is possible MACROSCOPIC Slow growers Colonies → heaped up, wrinkled, velvety, gray to olive to black pigment Reverse ○ jet black SDA with antibiotic MICROSCOPIC Cladosporium ○ chains of blastoconidia borne from branching conidiophores ○ elliptical conidia ○ acropetal older ones are at the base, younger ones are at the apex opposite: basipetal @mlstranses | 5 TREATMENT Surgical excision with wide margins Flucytosine or itraconazole for large lesions Locally applied heat is beneficial Relapses are common Phialophora ○ short flask-shaped phialides with collarette very visible since they are hyperpigmented D. PHAEOHYPHOMYCOSIS A term used to describe subcutaneous and systemic diseases caused by dematiaceous fungi other than those causing chromomycosis Tissue morphology is mycelial (mold form) CLINICAL MANIFESTATION [LEFT] F. pedrosi [RIGHT] F compacta Fonsecaea ○ F. pedrosoi polymorphic; phialides; chains of blastoconidia sympodial: conidia can grow at any part of the phialide or conidiophore ○ F. compacta spherical with broad base connecting the conidia − smaller, more compact (single base only) Rhinocladiella ○ Produces lateral or terminal conidia from conidiogenous cell ○ elliptical to clavate conidia Subcutaneous phaeohyphomycosis ○ cystic lesion, abscess ○ solitary, encapsulated (in healthy patients) Paranasal sinus phaeohyphomycosis ○ severe form of sinusitis Cerebral phaeohyphomycosis ○ immunosuppressed ETIOLOGIC AGENTS Subcutaneous ○ Exophiala jeanselmei ○ Wangiella dermatitidis Brain abscess ○ Xylohypha bantiana Paranasal sinusitis/subcutaneous ○ Bipolaris spicifera ○ Alternaria spp. ○ Curvularia spp. ✓NOTE: → Masson-Fontana stain: (tissue) irregular, swollen, septate hyphae with yeast-like structures (presumptive for phaeohyphomycosis). LABORATORY DIAGNOSIS MACROSCOPIC MICROSCOPIC Exophiala jeanselmei SCLEROTIC BODIES (Medlar bodies) ○ characteristic histologic findings in tissues with chromoblastomycosis ⇒ hallmark ○ copper-colored, septate cells that appear to be dividing (copper pennies) Slow growers (7-21 days) Initial: smooth, black, yeast-like Aged: filamentous, velvety, gray to black No growth at 40 deg C Common environmental fungal elements found in Dematiaceous Pale brown conidiophores form cylindrical annellides Picture below was stained with Lactophenol; hence the blue color @mlstranses | 6 decaying wood or soil enriched with organic waste Documented as human pathogens Bipolaris Wangiella dermatitidis Slow (3-4 weeks) Moist, shiny, yeast – like colonies → velvety periphery after incubation at 25°C Surface & reverse is olive black Neurotropic → has affinity for nervous tissues Can cause disseminated infections in immunocompromised patients The only species under Wangiella Rapid grower, gray-green to dark brown powdery colonies Flask-shaped to cylindrical phialides without collarettes Hyaline to pale brown, round to ovoid conidia Dematiaceous, septate; Twisted conidiophores / geniculate Oblong, multi-celled conidia Curvularia Rapid growing, most are fluffy, gray to black colonies Dematiaceous, septate Twisted conidiophores Multicellular conidia, curved with a central swollen cell Xylohypha bantiana (Cladophialophora bantianum) Colonies are moderately fast growing Olivaceous-gray, suedelike to floccose Grow at temperatures up to 42-43 deg C Long, sparsely branched, acropetal chains of conidia from undifferentiated conidiophores One-celled, pale brown, smooth- walled, ellipsoid to oblong conidia How to differentiate C. bantiana from other Cladosporium spp. ○ C. bantiana does not have pigmented hila/hilus, no conidial scar ○ Other Cladosporium spp. has pigmented hilus, conidial scar, and shield cell (phialides that has shield-like shape) Alternaria Rapid grower fluffy, gray to gray brown or gray green colonies Septated, golden brown conidia Conidiophores: simple or branched which bear a chain of large brown drumstick-like conidia @mlstranses | 7  E. RHINOSPORIDIOSIS Chronic infection Polypoid masses of nasal mucosa ○ mucosa of the nose, nasopharynx, soft palate ○ initially flat but develop into discolored, cauliflower-type polypoid masses 90% from India & Sri-Lanka 90% are males; divers; children & young adults Causative agent: Rhinosporidium seeberi LABORATORY DIAGNOSIS Direct microscopy is difficult HISTOLOGIC EXAMINATION ○ large, thick-walled sporangia packed with thousands of endospores ○ epithelial hyperplasia ○ cellular infiltrate of neutrophils, lymphocytes, plasma cells, and giant cells ○ ○ ○ ○ produces large spherules in lesions & epithelial cell tissue culture does not grow on artificial media stimulates epithelial cell proliferation associated with water, fish, aquatic insects F. LOBOMYCOSIS Chronic & progressive subcutaneous infection of humans and dolphins Small, hard nodular lesions on the extremities, face, or ear Verrucose, ulcerative, painless lesions resembling chromomycosis or mycetoma Causative agent: Loboa loboi ○ large, spherical or oval yeast ○ exhibit multiple budding & form short chains ○ multinucleated, thick walled ○ may be intracellular ○ occasional asteroid bodies @mlstranses | 8  LABORATORY DIAGNOSIS SPECIMEN ○ skin scrapings, exudative lesions, biopsies Direct microscopic examination (1) PAS, (2) methenamine silver, (3) FAT Not cultured artificially Has been maintained in mice LABORATORY DIAGNOSIS Histologic examination of infected tissue and culture ○ numerous branching hyphae ○ stain eosinophilic due to deposition of tissue elements or immune complexes on the walls ○ SDA without cycloheximide TREATMENT Surgery KI (Potassium iodide) Amphotericin B H. SUBCUTANEOUS PHYCOMYCOSIS Entomophthoromycosis basidiobolus Chronic self-limiting infection Initial small, firm, movable nodule on the torso or limb Skin is generally intact but may become very rough TREATMENT Surgical excision Sulfa drugs G. RHINOENTOMOPHTHOROMYCOSIS Entomophthoromycosis conidiobolae → rare infection of the nasal mucosa Tropical areas; young adult males Initial swelling in the nasal area Hard, subcutaneous nodules develop, and an acute or chronic inflammatory response may ensue Severe edema of the nose may block passage of air Causative agent: Entomophthora coronata (Conidiobolus coronatus) ○ soil saprophyte; insect parasite ○ SDA: flat, glabrous, colorless or gray to yellow colony ○ radial folds & thin aerial hyphae ○ large, spherical conidia with a crown of secondary conidia or hairlike appendages Causative agent: Basidiobolus haptosporus ○ isolated from GIT of beetles, frogs, lizards, etc. ○ colorless or brownish, thin, flat, glabrous colonies ○ radial folds develop with short, white aerial mycelium ○ wide hyphae with chlamydospores & spherical, smooth-walled zygospores TREATMENT Direct examination of tissue biopsies → multiple granulomata, giant cells, and eosinophils Broad, hyaline, branching hyphae Infrequent septa Surrounded by a sheath or eosinophilic material SDA without Cycloheximide @mlstranses | 9