Introduction to fungi and mycoses.pptx .

Mycoses

1. Introduction to fungi and mycoses, and SUPERFICIAL MYCOSES 9 th F e b r u a r y 202 2 E . M u b a n g a . B s c Msc. Dr Chileshe Lukwesa-Musyani

2. Dr Chileshe Lukwesa-Musyani Introduction - Fungi Aerobic Eukaryotic Have chitinous cell walls Ergosterol-containing plasma membranes (human cell wall contain cholesterol) Can grow as yeast (single celled, reproduce by budding Can grow as moulds (form multicellular hyphae which grow by branching and extension Or both yeast and mould

3. I n t r o d u c ti o n – f u n g i Eukaryotic Dr Chileshe Lukwesa-Musyani

4. Dr Chileshe Lukwesa-Musyani Differences between fungi and mammalian cells Animal Fungi Cell Structure Eukaryotic Eukaryotic DNA Diploid Haploid Ribosomes 80S 80S Cell wall No Chitin, mannans, glucans Cell membrane Predominantly cholesterol Predominantly ergosterol Microtubule affinity to for griseofulvin No Yes Cytosine deaminase No Yes Squalene epoxidase No Yes

5. Introduction – Fungi M o ld Dr Chileshe Lukwesa-Musyani

6. Introduction – Fungi Yeast Dr Chileshe Lukwesa-Musyani

7. Dr Chileshe Lukwesa-Musyani Fungal Growth Patterns M o l ds ( = F i l amentous F u n gi) Hyphae - Multicellular filamentous Mycelium - Collection of intertwined hyphae Vegetative hyphae act like roots, penetrating the supporting medium and absorbing nutrients Aeri a l hy p h a e p r o je c t a b ov e th e s u r fa c e o f t h e mycelium and bear the reproductive structures of the mold (often spread through the air)

8. Fungal Growth Patterns Yeasts – Unicellular fungi, reproduce by budding Dr Chileshe Lukwesa-Musyani

9. Aspergillus Ca n d i da a l b i cans Fungal Growth Patterns Dr Chileshe Lukwesa-Musyani

10. Dr Chileshe Lukwesa-Musyani Pathogenesis Disease may be due to toxin e.g. aflatoxin Host immune response

11. Dr Chileshe Lukwesa-Musyani Pathogenesis Cutaneous Subcutaneous Systemic

12. Dr Chileshe Lukwesa-Musyani Organism characteristics facilitating infection include: Growth at 37ºC Production of substances such as keratinases by dermatophytes (digest keratin in skin, hair, and nails) Ability to change form (dimorphic) Ability to adhere to surfaces (Candida) Anti-phagocytic capsules (cryptococcus) persistence following phagocytosis allowing dissemination with macrophages

13. Dr Chileshe Lukwesa-Musyani Host resistance to fungal infection Most infections mild and self-limiting Fatty acid content of the skin pH of the skin Mucosal surfaces and body fluids Epithelial turnover Competition with normal flora Transferrin Cilia of respiratory tract Cell mediated immunity Humoral plays a role

14. Dr Chileshe Lukwesa-Musyani Based on type of hyphae and sporulation into: Ascomycetes Septate hyphae and sexual spores in a sac (ascus) Basidiomycetes Septate hyphae and sexual spores in club-shaped cells (basidium) Phycomycetes Non-septate hyphae and sexual spores Deutromycetes Asexual spores. Most pathogenic fungi belong to this type

15. Dr Chileshe Lukwesa-Musyani Basidiomycota - Yeasts Cryptococcus neoformans Trichosporon beigelii Rhodotorula spp Malassezia furfur

16. Ascomycota Yeasts Candida spp Pneumocystis jiroveci Dimorphic fungi Histoplasma capsulatum Blastomyces Sporothrix Coccidiodes immitis Paracoccidiodes brasilensis Penicillium spp Moulds Aspergillus spp Epidermophyton Trichophyton Microsporum Fusarium Pseudallescheria boydii Madurella spp Acremonium spp Exophiala spp Dr Chileshe Lukwesa-Musyani

17. Zygomycota Mucor Rhizopus spp Dr Chileshe Lukwesa-Musyani

18. Dr Chileshe Lukwesa-Musyani Fungal Habitats Most clinically relevant fungi reside in the soil, in bird faeces, on vegetation, on the skin and mucous membranes of mammals. Some have distinctive ecologic and geographical niches.

19. Dr Chileshe Lukwesa-Musyani Epidemiology Host factors Immunocompromise increases opportunistic fungal infections Certain conditions predispose to specific organisms Diabetic ketoacidosis - Rhinocerebral mucormycosis AIDS - Histoplasmosis Antibiotics – candida vaginitis Environment affects the pattern of fungal diseases Some worldwide Lifestyle – e.g. gardener Sporothrix schenkii Living or Visiting specific regions e.g . Coccidiodis immitis in desert of South-western USA.

20. Dr Chileshe Lukwesa-Musyani Y E A S T S

21. Dr Chileshe Lukwesa-Musyani YEASTS Candida species Most common cause of fungal infection Candida albicans Non-albican species (e.g. C.glabrata, C.krusei, C.dubliniensis ) increasingly associated with invasive candidiasis and tend to be more resistant to certain antifungal drugs

22. Dr Chileshe Lukwesa-Musyani Yeasts: Candida species Pathogenesis Rise in infection relates to Medical interventions Use of antibiotics I nt r a ve n ous catheters Prosthetic implants GI tract surgery Immune suppression e.g. HIV/AIDS Therapies e.g. Steroids Immune response to candida by humoral and cellular mechanisms Virulence factors Surface molecules for adherence Acid proteases Ability to convert to hyphal form

23. Yeasts: Candida Infections Superficial infections Thrush Oral candidiasis characterised by white, creamy patches on tongue and oral mucosa Candida oesophagitis Gastrointestinal candidiasis vulvovaginitis Invasive Candida infection Candidaemia Blood stream infection CNS candidiasis As disseminated disease Cardiac candidiasis Candida endocarditis affects mostly the aortic and mitral valves Dr Chileshe Lukwesa-Musyani

24. Oral candidiasis http://health.allrefer.com/health/vaginal-yeast-infection-yeast-infections.html Candida albicans Dr Chileshe Lukwesa-Musyani vulvovaginitis

25. Dr Chileshe Lukwesa-Musyani Yeast: Candida species Invasive Candida infection Urinary tract infections – extension of vaginitis in women By sexual contact in men Bone and joint infections Candida osteomyelitis Intra-abodominal infection Peritonitis due to Dialysis GI perforation Surgery Disseminated candidiasis

26. Yeast: Cryptococcus neoformans Causes Cryptococosis a systemic fungal disease C.neoformans is encapsulated Four capsular serotypes A to D Serotype A = Cryptococcus neoformans var. grubii Serotype D = Cryptococcus neoformans var. neoformans Serotype B = Cryptococcus gattii Serotype B and C = Cryptococcus gattii Dr Chileshe Lukwesa-Musyani

27. Dr Chileshe Lukwesa-Musyani Yeast: Cryptococcus neoformans Epidemiology Ubiquitous environmental saprophyte Serotype A most common Serotype D world wide, isolated from pigeon droppings and nesting places Contaminated soil Decaying wood Transmission Inhalation of aerosolized organisms No evidence of person-to-person transmission 80-90% cryptococcal infections in AIDS

28. Yeast: Cryptococcus neoformans Pathogenesis Virulence factors – capsular polysaccharide, melanin, mannitol production, lack of soluble anti- cryptococcal factors in CSF Clusters of fungi spread throughout brain with no inflammation. Clinical features Cryptococcal meningitis Pulmonary cryptococcosis Other sites Skin lesions Bone lesions Oral lesions Dr Chileshe Lukwesa-Musyani

29. Cryptococcal skin lesions Cryptococcus neoformans is encapsulated Dr Chileshe Lukwesa-Musyani

30. Dr Chileshe Lukwesa-Musyani Yeast: Malessezia furfur Lipophilic yeast (grows in presence of certain fatty acids) Normal commensal of skin Cause skin infections Pityriasis versicolor – hypopigmented lesions Malassezia folliculitis Seborrheic dermatitis

31. Pityriasis versicolor Malassezia folliculitis Dr Chileshe Lukwesa-Musyani Seborrheic dermatitis

32. Dr Chileshe Lukwesa-Musyani MOULDS

33. Dr Chileshe Lukwesa-Musyani MOULDS: Aspergillus Aspergillus Found on decomposing vegetable material Causes Superficial cutaneous infection Allergies As p ergi ll o m a - pulmonary aspergilloma E ye – As p e r gi l l us keratitis Invasive pulmonary disease Disseminated -> b r ain

34. MOULDS: Mucormycosis Caused by a number of fungal species of class Zygomycetes Widespread in decaying matter Clinical disease limited to immunocompromised Infection acquired Inhalation Inoculation into skin abrasion Causes Rhinocerebral disease Pumonary disease Cutaneous disease Gastrointestinal disaese CNS disease Dr Chileshe Lukwesa-Musyani

35. Dr Chileshe Lukwesa-Musyani

36. Dr Chileshe Lukwesa-Musyani Moulds: Dermatophytes Group of fungi capable of invading the dead keratin of skin, hair and nails causing dermatophytosis (tinea) Also known as ringworm Three genera infect humans Epidermophyton Microsporum Trichophyton

37. Microsporum T r i c ho p h y t o n Epidermophyton Dr Chileshe Lukwesa-Musyani

38. Dr Chileshe Lukwesa-Musyani Other moulds C h r omom y c o s i s – diseases caused by dark brown cells – Chronic fungal infection, cutaneous and subcutaneous tissue Penicillium marneffei – dimorphic Pharyngeal, joint infections, pericarditis Histoplasma capsulatum dimorphic fungus, Pulmonary, disseminated, ocular Blastomyces dermatitidis dimorphic Any organ can be affected Coccidiodis immitis – dimorphic Pulmonary, disseminated P a r a c o cc i d i o i d es brasiliensis dimorphic Pulmonary, disseminated

39. Dr Chileshe Lukwesa-Musyani Classification of Mycoses The clinical nomenclatures used for the mycoses are based on the site of the infection, route of acquisition of the pathogen, type of virulence exhibited by the fungus.

40. Dr Chileshe Lukwesa-Musyani 1. Classification Based on Site Mycoses are classified as superficial, cutaneous, subcutaneous, systemic (deep) infections 🞄 de p ending o n th e ty p e a n d d eg r ee o f tis s ue involvement and the host response to the pathogen.

41. http://levisageskin.com/microder D m r C a hi b les r h a e s Lu i k o w n es - a h -M o us w yan - i it-works/ skin

42. Classification Based on Site http://ouhsc.edu/histology/Text%20Sections D /I r n C t h e il g e u sh m e L e u n k t w .h es t a m -M l usyani Superficial mycoses are limited to the stratum corneum and essentially elicit no inflammation.

43. Dr Chileshe Lukwesa-Musyani 1. Classification Based on Site Superficial mycoses are limited to the stratum corneum and essentially elicit no inflammation. Cutaneous infections involve the integument and its appendages, including hair and nails. Infection may involve the stratum corneum or deeper layers of the epidermis. Inflammation of the skin is elicited by the organism or its products.

44. 1. Classification Based on Site Subcutaneous mycoses range of different infections characterized by infection of the subcutaneous tissues point of traumatic inoculation. An inflammatory response develops in the subcutaneous tissue frequently with extension into the epidermis. Dr Chileshe Lukwesa-Musyani

45. Principal tissue sites of deep mycoses in comparison to those of the superficial, cutaneous, and subcutaneous mycoses. Dr Chileshe Lukwesa-Musyani

46. Dr Chileshe Lukwesa-Musyani 2. Classification Based on Route of Acquisition Infecting fungi may be either exogenous : Routes of entry for exogenous fungi include airborne, cutaneous percutaneous endogenous . Endogenous infection involves colonization by a member of the normal flora or reactivation of a previous infection.

47. Dr Chileshe Lukwesa-Musyani 3. Classification Based on Virulence Primary pathogens Establish infections in normal hosts. Opportunistic pathogens cause disease in individuals with compromised host defence mechanisms.

48. Dr Chileshe Lukwesa-Musyani END

49. Dr Chileshe Lukwesa-Musyani Superficial Mycoses Superficial mycoses are limited to the stratum corneum and essentially elicit no inflammation.

50. Dr Chileshe Lukwesa-Musyani MYCOSES Superficial Superficial Mycoses include the following fungal infections and their etiological agent: black piedra ( Piedraia hortae ), white piedra ( Trichosporon beigelii ), pityriasis versicolor ( Malassezia furfur ), tinea nigra ( Phaeoannellomyces werneckii ).

51. Superficial: Blac k p iedr a ( Piedraia h o r t ae) small firm black nodule involving the hair shaft . Dr Chileshe Lukwesa-Musyani

52. Superficial : W h it e p iedr a d u e t o T b eigelii i s c h aracte r ize d b y a soft, friable, beige nodule of the distal ends of hair shafts. Dr Chileshe Lukwesa-Musyani

53. Superficial : Tinea versicolor (= Pityriasis versicolor ) Malassezia furfur Hypopigmentation or hyperpigmentation of skin of the neck, shoulders, chest, and back Dr Chileshe Lukwesa-Musyani

54. T in e a nigr a m o st typ i cally p res e nt s as a b r o w n to black silver nitrate-like stain on the palm of the hand or sole of the foot. Dr Chileshe Lukwesa-Musyani

55. Dr Chileshe Lukwesa-Musyani Cutaneous Mycoses Cutaneous infections involve the integument and its appendages, including hair and nails.  Infection may involve the stratum corneum or deeper layers of the epidermis. Inflammation of the skin is elicited by the organism or its products.

56. Dr Chileshe Lukwesa-Musyani Cutaneous Mycoses Cutaneous My c o ses may b e c l assi f ie d as dermatophytoses dermatomycoses.

57. Dr Chileshe Lukwesa-Musyani Dermatophytoses are caused by the agents of the Dermatophytoses genera Epidermophyton, Microsporum, Trichophyton

58. Trichophyton spp Epidermophyton Microsporum spp Dermatophytes Dr Chileshe Lukwesa-Musyani

59. Cutaneous Mycoses The dermatophytoses are characterized by an anatomic site-specificity according to genera. E.g Epidermophyton floccosum infects only skin and nails, but does not infect hair shafts and follicles. Microsporum spp . infect hair and skin, but do not involve nails. Trichophyton spp . may infect hair, skin, and nails. Dr Chileshe Lukwesa-Musyani

60. Tinea barbae – Ringworm of beard region Tinea capitis – Ringworm of scalp and hair Tinea corporis – Ringworm of the smooth skin of the body Tinea cruris – Starts in groin area (“Jock itch”) – Caused by Trichophytum rubrum D e r ma t o p h yto s e s Dr Chileshe Lukwesa-Musyani

61. Tinea pedis – Classically interdigital (”Athlete’s foot”) Tinea unguium Infection of finger and toe nails Often associated with T. pedis D e r mato p h ytoses Dr Chileshe Lukwesa-Musyani

62. Dr Chileshe Lukwesa-Musyani Cutaneous Mycoses Dermatomycoses Cutaneous infections due to other fungi, the most common of which are Candida spp.

63. Dr Chileshe Lukwesa-Musyani END