DERMATOPHYTES SUPERFICIAL MYCOSES K R.pptx

DERMATOPHYTES K R.pptx

1. DERMATOPHYTES (SUPERFICIAL MYCOSES) K R MICRO NOTES 1

2. INTRODUCTION Dermatophytes are cutaneous fungi which infect only keratinized tissue by liberating keratinase enzyme which helps them to invade keratinized tissue. Ringworm (Tinea)infections are common diseases of the startum corneum of the skin, hair and nail . They are referred to as “ Dermatophytosis” or tinea . Ringworm infections are caused by about 20-40 species of dermatophtye fungi which are grouped into three genera: Trichophtyon – Hair, skin, nail Microsporum – Hair, skin Epidermophyton – Skin, nail K R MICRO NOTES 2

3. Epidemiology Anthropophilic D.Gruby (1842-1844) detected the fungus in – Man tinea as a causative agent and C.P.Robin (1853) Zoophilic described Microsporum mentagrophytes that – Animals was transferred to trichophyton by Blanchard Geophilic (1896). – Soil K R MICRO NOTES 3

4. K R MICRO NOTES 4

5. TRICHOPHTYON CLASSIFICATION Kingdom : Fungi Division : Ascomycota Class : Eurotiomycetes Order : Onygenales Family : Arthrodermataceae Genus : Trichophyton The genus Trichophyton is characterized by the development of both Smooth-walled , macro-conidia and micro-conidia. Most important and common causes of infections of the feet, skin and nails. K R MICRO NOTES 5

6. TRICHOPHTYON CLASSIFICATION Kingdom : Fungi Division : Ascomycota Class : Eurotiomycetes Order : Onygenales Family : Arthrodermatacceae Genus : Trichophyton The genus Trichophyton is characterized by the development of both Smooth-walled , macro-conidia and micro-conidia. Most important and common causes of infections of the feet and nails. K R MICRO NOTES 6

7. Morphology The morphologies vary depending on the growth temperature, growth medium and the type of species. Most of the species produce either macroconidia or microconidia or both. Their occurrence of shapes and sizes depending on the medium of growth. Macro conidia Micro conidia They are small, cigar shaped (cylindrical ). They are spherical in shape They have thick walled cell walls and tend to occur in clusters. They may occur singly or in clusters and they produce on the terminal branches on the hypal structures. K R MICRO NOTES 7

8. Trichophytons produces spiral-shaped hypal structures, from which the conidial spores originate. They do not form conidiophores. K R MICRO NOTES 8

9. Important species of trichophyton With conidia Trichophtyon rubrum Trichophtyon mentagrophytes Trichophtyon tonsurans With hyphae T. schoenleinii T. violaceum T. verrucosum K R MICRO NOTES 9

10. Trichophtyon rubrum It is the most common cause of dermatophytosis. It occurrence is world wide. It is anthropophilic species of dermatophytes. It is a keratinophilic filamentous fungus. It affects human feet, skin, and finger nails, causing chronic infections on these body parts ( granulomatous lesions). K R MICRO NOTES 10

11. Micrscopically, endothrix and ectothrix invasion may be observed on infection. They form both microconidia and macroconidia. Macroconida occur, they are in large numbers, with terminal projections. Microconidia occur, they vary in shapes and sizes. They may be slender calvate to pyriform. Urease test is negative K R MICRO NOTES 11

12. Trichophyton mentagrophytes This is a zoophilic species with a cosmopolitan distribution. it commonly affects animals such as mice, cats, horses, sheep and rabbits. In humans cause ringworm , majority in rural areas. Grape like clusters of microconidia. No red pigment. Hair perforation test is positive. Cigar shaped macroconidia Urease positive. It is a contagious fungus which primarily causes tinea pedis , tinea unguium , tinea corporis and Tinea capitis. K R MICRO NOTES 12

13. Pathogenesis K R MICRO NOTES 13

14. Clinical Manifestations of Trichophyton spp infections Tinea corporis ( ringworm) Tinea pedis (athlete’s foot) Tinea cruris (jock itch) Tinea barbae Tinea unguium ( onychomycosis ) Caused by T. mentagrophytes Trichophyton rubrum and T. mentagrophytes Trichophyton rubrum and T. mentagrophytes Trichophyton rubrum and T. mentagrophytes Trichophyton rubrum and T. mentagrophytes It affects the nonhairy , smooth skin. It occurs in the interdigital spaces on feet of persons wearing shoes. It is associated with groin erythematous scaling lesions in the intertriginous area Affects the beard hair It affect the nail It is characterized by circular patches with advancing red, vesiculated border and central scaling. By acute infection associated with itching and red vesicular . It is characterized by Edematous, erythematous lesion. The nails thickened or crumbling distally , discolored , lusterless The infection is pruritic Chronic infection also characterized by itching, scaling, fissures. And the lesions pruritic. It is usually associated with Tinea pedis. K R MICRO NOTES 14

15. Tinea corporis Tinea pedis Tinea cruris Tinea barbae Tinea unguium K R MICRO NOTES 15

16. Laboratory diagnosis Specimen collection Direct examination Culture Identification K R MICRO NOTES 16

17. Specimen collection Hair – plucked , not cut, from edge of lesion. Skin – wash, srape from margin of lesion. Nails – Scrapings from nail bed or infected area. Transport in sterile petri dish K R MICRO NOTES 17

18. Direct examination Examine hair for flourescence – Wood’s lamp K R MICRO NOTES 18

19. Direct examination Examine specimen for fungal elements – Skin 10% KOH for one hour. – Hair 20% KOH for 10 hours. – Nails 20-40% KOH for 10 hours. With Calcofluor white stain K R MICRO NOTES 19

20. Culture Media Trichophyton grow well in Sabouraud Dextorse agar within two weeks at room temperature producing cylindrical, smooth walled macroconidia and microconidia Trichophyton rubrum develops white, cottony surface and deep red nondiffusible pigment in reverse growth . They produces small pear shaped micorconidia . K R MICRO NOTES 20

21. Culture media Trichophyton mentagrophyte produces a cottony to granular growth, grape clusters of spherical microconidia on terminal branches. They also form coiled or spiral hyphae. K R MICRO NOTES 21

22. Identification Identification based on the colonial appearance and color , pigment production and micromorphology of any spores produced . Special test exist for differentiating certain morphologically similar species. Thus, the ability of t. mentagrophytes to produce urease within 2-4 days distinguishes from T. rubrum. K R MICRO NOTES 22

23. Treatment Topical therapy is satisfactory for most skin infection, but oral antifungals are required to treat infections of the nail and scalp, and severe or extensive skin infections. Itraconazole and terbinafine are used for the treatment of tinea corporis, tinea pedis and for the nails also. Tinea capitis (scalp infection) Are treated for several weeks With oral administration of Griseofulvin or terbinafine. K R MICRO NOTES 23

24. Microsporum CLASSIFICATION Kingdom : Fungi Division : Ascomycota Class : Eurotiomycetes Order : Onygenales Family : Arthrodermatacceae Genus : Microsporum Microsporum spp are dermatophyte fungi that cause cutaneous infections of the hair, skin. As a dermatophyte, it is restricted to the nonviable skin tissues because of its inability to grow in temperatures above 37C. K R MICRO NOTES 24

25. It is highly transmissible fungus from animals to humans therefore it is a zoonotic fungus. They occur world wide, naturally living in the soil. This include the Tinea capitis which cause the fungal infection of the scalp hairs that fungi penetrate the hair follicles outer root sheath, and result in an inflammatory types is characterized by painful nodules that contain pus and losses hair. it is common in 3-14 years children but it can affect any group Tinea corporis affects the arms and legs , itching, scaling, redness, rashes and may be dry. K R MICRO NOTES 25

26. Characteristics of Microsporum spp They reproduce asexually forming Macroconidia and microconidia. Macro conidia Micro conidia They are larger asexual spores They are smaller Hyaline and multiseptate hyaline and single celled Spindle shaped to obovate pyriform to clavate shaped , having smooth call wall They are 7-20 m by 30-160 m in size 2.5-3.5 m by 4.7 m in size K R MICRO NOTES 26

27. Important species of Microsproum Microsporum gypseu Microsporum canis Microsporum audouinii K R MICRO NOTES 27

28. Microsporum audouinii Anthropophilic Hair fluoresce yellow- green when examined under wood’s lamp. Velvety, brown colored colony Macroconidia – distorted shape or absent Terminal chlamydospore present K R MICRO NOTES 28

29. Microsporum gypseu Geophilic Hair do not fluoresce Spindle shaped, round end macroconidia are abundant . There is no curve at the end of macroconidia . K R MICRO NOTES 29

30. Microsporum canis Zoophilic (Dogs and cats) Hair fluoresce yellow – green Spindle shaped, rough walled, multi segmented, curved end , warty projections macroconidia are abundant. Microconidia are very few. K R MICRO NOTES 30

31. Pathogenesis K R MICRO NOTES 31

32. Laboratory diagnosis Specimen collection Direct examination Culture Identification K R MICRO NOTES 32

33. Lab diagnosis Specimens Skin scrapings, nail scrapings, tissue biopsies Direct examination KOH wet mount using the skin scrapings and pus. K R MICRO NOTES 33

34. Culture examination Potato Dextrose Agar Microsporum audouinii produce pinkish-brown or salmon-colored fluffy colonies K R MICRO NOTES 34

35. Microsporum canis produces bright yellow colonies. Trichophyton Agar Microsporum audouinii produces flat , white, suede- like to downy, with yellow-brown reverse colonies with a furry texture. Microsporum canis forms flat, white, suede-to downy , with yellow-brown reverse colonies. Rice Grain Agar Microsporum canis produces white aerial mycelium with the production of yellow pigment. K R MICRO NOTES 35

36. Treatment Topical or oral antifungals including imidazole, ciclopirox, naftifine or terbinafine in cream, lotion or gel for mild – moderate lesions arising due to tinea corporis and tinea capitis . Use of antifungal shampoos for treatment and also for the prevention of fungal infection spread. Extensive infections can be treated with oral Itraconzole for a prolonged period of time. K R MICRO NOTES 36

37. K R MICRO NOTES 37

38. K R MICRO NOTES 38

39. MADURA FOOT (SUBCUTANEOUS LAYER) K R MICRO NOTES 39

40. INTRODUCTION Madura foot is also know as “Mycetoma” or “Madura mycosis” ( tumor-like) Mycetoma is a chronic, granulomatous infections of the skin, subcutaneous tissue, fasica and bone. Individuals who walks in barefoot in dry, dusty conditions and agriculture fields. K R MICRO NOTES 40

41. EPIDEMOLOGY K R MICRO NOTES 41

42. MYCETOMA - TYPES Eumycetoma – due to fungus (40%) Actinomycetoma – due to bacteria (60%) K R MICRO NOTES 42

43. Eu Mycetoma Actino Mycetoma Caused due to Caused by Fungi Caused by Bacteria Grains Black or white White/ red Granules Black granules if caused by Madurella mycetomatis White granules if caused by Pseudallescheria boydii White to Yellow granules if caused by Actinomadura madurae , Nocardia species, Streptomyces som -alien-sis Pink to Red granules if caused due to Actinomadura pelletieri Sinues Appear late, few in number Appear early, numerous with raised inflamed opening Tumor Single , well defined margins Multiple tumor masses with ill defined margins Discharge Serous Purulent Bone OsteoSclerotic lesions OsteoLytic lesions Grains contain Fungal hyphae Filamentous bacteria K R MICRO NOTES 43

44. K R MICRO NOTES 44

45. K R MICRO NOTES 45

46. K R MICRO NOTES 46

47. Pathogenesis Organism enter through a prick in the foot usually who walks in barefoot Reaches deeper plane in the foot That causes chronic granulomatous inflammation causes pale, painless, firm nodules Formation of vesicles Burst to form a discharging sinuses K R MICRO NOTES 47

48. K R MICRO NOTES 48

49. Lab Diagnosis Specimen collection Grains ( collect after cleaning with antiseptic , using sterile gaze or loop, press the sinuses from periphery ). Then sterile pads for 8-12 hour, it examined for color, size and consistency which differ according the causative agents. Grains examined microscopically after crushed between two slides with KOH or stained by gram. K R MICRO NOTES 49

50. Culture Grains as well as exudate are cultured on suitable media . In case of black grains Sabouraud’s dextrose agar (SDA) and dermatophyte test medium is suitable. If it is white grains SDA or malt extract agar as well as blood agar are used and LJ media. Incubation time and degree of temperature is differ from bacterial isolates or fungi. Lab diagnosis contd… K R MICRO NOTES 50

51. Lab diagnosis contd… In fugus identify by observation of the growth rate, colony morphology, production of conidia and their sugar assimilation patterns. In bacteria identified by their growth rate, colony morphology, urease test Acid fastness and media containing casein, tyrosine, xanthine. Nocardia is partially acid fast. K R MICRO NOTES 51

52. Treatment SURGERY then Drugs ( but in pathogenesis they never mentioned about pain or complications) Eumycetoma Itraconazole Amphotericin B Actinomycetoma Welsh regimen = Amikacin (systematic aminoglycoside) + Cotrimoxazole ( sulphamethoxazole + trimethoprim) K R MICRO NOTES 52

53. Reference MEDICAL MICROBIOLOGY – DAVID GREENWOOD – RICHARD C.B.SLACK TEXTBOOK OF MICROBIOLOGY – DR C P BAVEJA http://micronotes.com MEDICAL MICROBIOLOGY – SATISH GUPTA K R MICRO NOTES 53