Dematiaceous fungi.pptx

a complete ppt on dematiaceous fungi

1. DEMATIACEOUS FUNGI ( Phaeoid Fungi) Faculty in-charge: Dr. Shugufta Roohi Presented by: Dr. Umaya Majid. M o derated by: Dr. Iqra Majid. - Mycology -

2. 01 3 Table of contents 02 Classification 04 Dematiaceous fungi. 06 Introduction to L aboratory diagnosis. 05 Epidemiology & Pathogenesis. of fungi. Disease Spectrum. Treatment.

3. Classification 01 O f Fungi

4. Fungal pathogens Molds Yeasts Aseptate Hyphae Septate Hyphae Dematiaceous Molds Zygomycetes Dimorphic Molds Hyaline Molds Hyaline Septate Molds Mucorales Rhizopus, Mucor. Rhizomucor Entomophthorales Bipolaris spp , Alternaria spp , Phialophora spp , Exophiala spp , Acremonium spp , Candida sps . Cryptococcus neoformans. Trichosporon . Dermatophytes Aspergillus sps . Fusarium. Trichoderma Microsporum , Trichophyton, Epidermophyton. Histoplasma, Coccidioides, Blastomyces.

5. Dematiaceous Fungi General characteristics: Large group of rapidly growing saprotrophic molds producing a melanin like pigment resulting in darkly pigmented hyphae visually recognized as dark grey or black colonies both on the obverse & the reverse side.

6. Ubiquitous in nature, exist as saprotrophes . Humans & animals serve as accidental hosts after traumatic inoculation of organism into cutaneous & subcutaneous tissue. Infections range from mild, hardly noticeable cutaneous infections to fatal brain diseases in otherwise healthy individuals.

7. Virulence Factor Clinical Significance Presence of melanin in cell walls, is believed to be a major virulence factor. - It gives protection against solar irradiation. Diseases by melanized fungi are rare , they are significant because of their occurrence in otherwise healthy individuals , and no notable increase in their frequency is noticed with the emergence of immunocompromised hospital populations.

8. Microscopically Dark yellow brown mycelium composed of uniform hyphae with parallel walls, having true septate hyphae. Cell wall contain melanin like compound making hyphae darkly pigmented. Darkly stained macrconidia . In H/P sections these pigments may be accentuated by Fontanna masson stain .

9. Disease Spectrum Dematiaceous Fungi Superficial infections Mycetoma Chromoblastomycosis Phaeohyphomycosis

10. Genera of Medical Importance Include

11. Superficial Infections Tinea Nigra ( Hortae werncekii ) Superficial skin infection. Brownish black, non-scaly, macular patches. Centrifugal extension, darkest at periphery. Palms (tinea nigra palmaris) & sole (tinea nigra plantaris). - H. werneckii - halophilic saprotrophe . - Hyper- hydrotic individuals. D/D : 1. Benign nevus. 2. Malignant melanoma. 3. Pityriasis versicolor. Tinea nigra Acral lentiginous melanoma Pityriasis versicolor

12. Superficial Infections ( cont ) Black Piedra ( Piedraia hortae ) Tinea Nodosa. Primarily occur in tropical areas. Nodular type infection of hair shaft ( scalp ). Starts under the cuticle, grow outside & envelope hair shaft, penetrate cortex. Gritty hard, brown-black nodules, firmly attached to hair shaft, metallic sound while combing. Nodules: spores embedded in cement-like substance or branched hyphae with asci. D/D: 1. Nits of pediculosis. 2. Tinea capitis. Black piedra Nits of pediculosis Tinea capitis

13. The recent DNA sequence data indicate that nearly all etiological agents of Phaeohyphomycosis , Chromoblastomycosis and Phaeoid taxa of Eumycetoma belong to a single clade of Loculoascomycetes fungi.

14. Subcutaneous Infections

15. Mycetoma Eumycotic Bacterial Black grain White grain Actinomycotic Chronic Granulomatous infection of subcutaneous tissue. Triad: Tumefaction, Multiple draining sinsuses , Granules in discharge. Swelling, purplish discoloration, serous or serosanguineous discharge. Mostly Lower extremities (any part).

16. Progressive destruction- bone, muscle other tissues, requires amputation. Mostly occurs tropical region but can occur in temperate zone. Multiple draining sinuses Lytic bone lesions on X-ray

17. Chromoblastomycosis Chromoblastomycosis is cutaneous & S/C infection characterized by formation of polymorphic, verrucoid , crusted or ulcerated lesions. Characteristic Sclerotic Bodies present. - muriform cells (ideal). - medlar bodies. - copper-penny bodies. - intermediate vegetative state b/w yeats and hyphae. Papule slowly spreads to form warty or tumor like lesion (cauliflower like growth). Dorsal surface of feet & legs, may involve head & neck. Widely distributed mostly in tropical and subtropical areas.

18. These infections cause hyperplasia (PEH) of the epidermis of the skin, which may be mistaken for squamous cell carcinoma. Characteristic black dots Mimicking SCC

19. Systemic Infections

20. Phaeohyphomycosis Greek Phaeo = dusky, gray. Concept of “ phaeohyphomycosis ’’ was 1st proposed by Ajello et al in 1986 to “cover all infections of cutaneous, subcutaneous, & systemic nature caused by hyphomycetous fungi that develop in host tissues in the form of dark walled, dematiaceous, septate mycelial elements. Characterized by multiple stellate abscesses, progress to circumscribed lesion with central cavity filled with pus and surrounding fibrous wall. Phaeohyphomycosis applies to several clinical entities : 1. Phaeohyphomycotic cysts 2. Sinusitis 3. Keratitis 4. E ndocarditis 5. P neumonia 6. B rain abscess 7. Systemic infections.

21. Cutaneous Phaeohyphomycosis of the forearm caused by Exophiala jeanselmei

22. A lternaria cutaneous infection Bipolaris chronic sinusitis

23. Cutaneous phaeohyphomycosis of the face

24. Subcutaneous phaeohyphomycosis

25. Ring infiltrate in a case of keratitis caused by dematiaceous fungi Corneal picture of a case of dematiaceous fungal keratitis presented as peripheral ulcerative keratitis

26. Identification of Dematiaceous Fungi The growth rate. Colony morphological features. Microscopic morphological features.

27. A common theme in Laboratory diagnosis: Sample collection: Superficial infections: Hair nodules ( Black Piedra ), skin scrapings and biopsy ( Tinea Nigra ). Subcutaneous infections: Grains ( Mycetoma ), skin scrapings with black dots or biopsy specimen ( Chromoblastomycosis ). Systemic infections: Aspirates from cysts, curretings from plaques, nodules and drained abscesses ( Phaeohyphomycosis ). Direct examination: KOH Mount (20%)- morphology of hyphae. Culture: SDA with antibiotics- colony characteristics.

28. Superficial Infection Tinea Nigra Hortaea werneckii Grows slowly , 2- 3 weeks. Colony morphology: Tar black, smooth, slimy & glistening, yeast- like. Microscopically: Hyphae are wide, densely septate (at maturation), becoming dark brown & thick walled. Conidia are produced by annellophores, bear successive rings (annellids)

29. Superficial Infection ( cont ) Black Piedra Piedraia hortae Grows slowly. Colony morphology: small, folded, velvety and dark brown to black in color. reddish brown diffusible pigment (obverse) black in color (reverse). Microscopically: Septate hyphae, ascostromata, asci, and ascospores are visualized. Hyphae are darkly pigmented.

30. Superficial Infection ( cont ) (a) 10% potassium hydroxide (KOH) examination of black colored nodule shows a concretion forming a collar around hair shaft. Concretions are made up of filamentous hyphae, held together in a mass by cement like substance. Spores are seen at the edges of the nodule (←), (b) KOH mount of crushed nodule shows brown dematiaceous closely septate hyphae (H) with few chlamydospores (Ch). (c) Culture on Sabouraud's dextrose agar shows small, compact, blackish conical colonies with velvety surface. (d) Microscopic examination of the colonies showing round, dark brown, globus ascus (→) with ascospores.

31. White Grain Mycetoma P. Boydii Grows rapidly . Initial growth- white fluffy colony, mousy gray in several weeks A. falciforme Grows slowly . Produce gray brown colonies.

32. Black Grain Mycetoma M. mycetomatis Grows slowly . Colony morphology: W hite to olive brown. Brown diffusible pigment (characteristic). Microscopically : SDA: Moniliform septate hyphae with Chlamydospores. CMA: short pointed conidiophores, conidia at tips of flask-shaped phialides.

33. Black Grain Mycetoma E. jeanselmei Grows slowly. Colony morphology: Yeast-like and darkly pigmented olive to black velvety appearance with the production of aerial hypha. Microscopically: Daughter cells are produced by annellides rather than true bud Conidiophores are cylindrical and have a tapered tip. Annellations may be visible at the tip. Clusters of oval to round conidia are apparent.

34. Identification of Chromoblastomycosis KOH Mount : Sclerotic bodies (rounded, brown, 4 to 10 μm in diameter and resemble “copper pennies” ). Macroscopically: Heaped up colonies. Darkly pigmented. Gray to Olive Black & Velvety. Reverse side of colony is jet black . Microscopic examination is necessary for definitive identification. Sclerotic bodies

35. Cladosporium spp. Microscopically: Long chains of elliptical conidia ( blastoconidia ). Borne from erect, tall, branching conidiophores. Dysjunctor & shield cells.

36. Phialophora spp. Phialophora verrucosa: Microscopically : Phialides with a distinct cup or flask-shaped collarette. P. richardsiae : Microscopically: Produces phialides with a flattened or saucer-like collarette . Conidia are produced endogenously and occur in clusters at the tip of the phialide.

37. Fonsecaea spp. Microscopically: Conidial heads with sympodial arrangement of conidia, with primary conidia giving rise to secondary conidia. Cladosporium type. Phialophora type. Rhinocladiella type. Rhinocladiella type of sporulation: Single-celled conidia are produced on denticles that arise from all sides of conidiophores (sympodially).

38. Identification of Other Dematiaceous Fungi

39. Macroconidia with Transverse & Longitudinal Septa

40. Alternaria spp. Microscopically: Hyphae are septate & golden brown pigmented. Conidiophore: Simple, sometimes branched. Short chains of large, brown, smooth walled, multicelled macroconidia. Shaped like drumsticks with elongated beak of one conidium butting against the rounded blunt end of next.

41. Ulocladium spp. Microscopically: Muriform macroconidia. Not arranged in chains. Borne from short, twisted ‘‘ bent-knee’’ or geniculate conidiophore.

42. Stemphylum spp. Microscopically: Muriform macroconidia similar to that of Ulocladium . Borne singly at the apex of a short, straight non geniculate conidiophore Macroconidia are swollen & rounded at the tip (bale of cotton on a stick).

43. Epicoccum spp. Microscopically: Hyphae typically form focal repeated branching & rebranching of certain threads forming masses known as sporodochia . Short conidiophore arise from these masses. Macroconidia are multi-celled, muriform, spherical to slightly club shaped. Roughened on surface (blackish wart like appearance).

44. Macroconidia with Transverse Septa

45. Bipolaris spp. Microscopically: Hyphae are dematiaceous & septate. Conidiophores have knee like bends (geniculate) Macroconidia are Elliptical to oval ,arranged sympodially. Thick walled, smooth surface. Conidia when incubated in direct water or saline mounts at 25 °C for 8 to 24 hours, produce germ tube that arise from both the ends of macroconidia (thus name bipolaris).

46. Drechslera spp. Microscopically: Hyphae septate & darkly pigmented. Geniculate conidiophore. Cylindrical, multi-celled macroconidia (sympodially). In saline mounts single germ tube at right angle to the long axis of conidium is formed.

47. Curvularia spp. Microscopically: Hyphae are dematiaceous & septate. Conidiophore are geniculate & twisted. Conidia are golden brown, arranged sympodially, multi-celled . Central cells grow more rapidly & are larger than those at ends(lighter) resulting in Curved or “ boomerang ’’ appearance.

48. Exserohilum spp. Microscopically: Hyphae are septate & dematiaceous. Conidiophore are geniculate. Conidia are produced sympodially. Conidia are elongate, ellipsoid to fusoid, pencil shaped & exhibit a prominent hilum that is truncated & protruding (arrows).

49. Macroconidia Borne Singly Or Through Special Conidiation

50. Nigrospora spp. Macroscopically: Colonies are rapidly growing. Cottony dirty white turn gray with maturity. Reverse of colony also becomes pigmented. Microscopically: Conidia are solitary, large subglobose , smooth. Jet black borne on tip of inflated urn shaped conidiophore.

51. Phoma spp. Macroscopically: Buff to dark brown. Glabratous . Microscopically: Large dark brown to black, smooth walled, leathery, sac like called pycnidia . Within Pycnidia are borne myriad cylindrical, spindle shaped or spherical hyaline one celled conidia .

52. Chaetomium spp. Macroscopically: Initially white. M ay become yellow, yellow-green. or copper colored. Microscopically: Large ,spiked hyphae simulating the legs of spider.

53. Treatment Options Medical Surgical Polyene. Flucytosine. Itraconazole. Voriconazole. Subcutaneous cyst. Ulcerative lesions- Debridement. Brain abscess- Debulking Note: Eumycetomas in the extremities can be extremely difficult to manage, because of their indolent nature, scarring, fistula formation, and bone involvement and the ability to obtain disease-free tissue margins may be difficult via surgery, therefore adjunctive medical therapy is required.

54. Concluding Remarks Melanized fungi in general are underestimated as etiologic agents of varied clinical entities primarily attributed to difficulties in classical identification owing to often slow growth and poor morphology . However, this scenario has changed considerably with the introduction of molecular diagnostics. Nearly all species can confidently be recognized by the rDNA ITS barcoding marker. A majority of the melanized fungi are associated with non-life-threatening infections in the clinical lab and are generally not reported. However, despite their rarity, they are highly relevant because of their potential to infect and kill apparently healthy individuals.

55. Chronic CNS infections may remain unnoticed for a long time, or are misdiagnosed as tumors, and then take a fatal course. Disseminated and subcutaneous infections, such as chromoblastomycosis, are recalcitrant to therapy and may relapse despite in vitro susceptibility to the antifungals. The treatment options for melanized fungi are generally limited.

56. Thanks!