1 / 56

Mycology

Mycology. Dental / Optometry Fundamentals II Stephen A. Moser, Ph.D. 10/26/2011. Epidemiology. Geography Endemic mycoses Worldwide mycoses Transmission of infection Respiratory inhalation (systemic mycoses) Cutaneous inoculation (sporotrichosis)

kasi
Download Presentation

Mycology

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Mycology Dental / Optometry Fundamentals II Stephen A. Moser, Ph.D. 10/26/2011

  2. Epidemiology • Geography • Endemic mycoses • Worldwide mycoses • Transmission of infection • Respiratory inhalation (systemic mycoses) • Cutaneous inoculation (sporotrichosis) • Systemic invasion by opportunistic normal flora (candidiasis) • Contact with infected hosts (dermatophytoses)

  3. Epidemiology (Cont.) • Risk factors and manifestations of disease • True pathogens versus opportunists • Environmental risk factors for systemic fungal disease • Location and travel • Occupation • Host defenses and susceptibility to systemic fungal disease (CMI most important) • Congenital and acquired T cell deficiencies (including AIDS) • Immunosuppression (transplants and malignancies) • Diabetes mellitus

  4. Endemic Distribution for Blastomycosis

  5. General Characteristics • Aerobic - obligate or facultative • Eukaryotic: membrane bound nucleus and cytoplasmic organelles (may be multinucleate) • Achlorophyllous • Morphology (unicellular or multicellular) • Saprophytic (heterotrophic)

  6. Characteristics of Fungal Cells • Cell wall: multilayered polysaccharide • Cellulose, glucans, mannans, chitin, polypeptides • Absence of teichoic acids, peptidoglycan, LPS • Cell membrane • Phospholipid bilayer • Ergosterol (relate to chemotherapy) • Cytoplasm- typical eukaryotic organelles • Nucleus- either uninucleate or multinucleate

  7. Characteristics of Fungal Cells • Capsule • Present in some species (e.G. Cryptococcus neoformans) • Amorphous polysaccharide coating • Functionsand activities • Antiphagocytic • Antigenic

  8. Characteristics of Fungal Cells • Growth forms • Yeast - unicellular fungi which reproduce by budding (Cryptococcus) • Mold - hyphae (mycelium) • Septate hyphae (Aspergillus) • Non-septate, coenocytic hyphae (Mucor) • Pseudohyphae (Candida albicans) • Thermal dimorphism

  9. Differences Between Bacteria and Fungi

  10. Examples of Yeast & Pseudohyphae Blastoconidia Pseudohypha

  11. Blastomyces dermatitidis Thermal Dimorphism

  12. Example of True Septate Hyphae

  13. Non-septate Hyphae

  14. Asexual Reproduction • Conidia (spores) – asexual structures • Blastospores – formed by budding yeasts (Blastomyces) • Chlamydospores – terminal or intercalary cells with thick walls (Candida albicans) • Arthrospores – formed by fragmentation of hyphae (Coccidioides immitis) • Sproangiospores – formed in sporangia by cleavage (Rhizopus)

  15. Classification Based onSexual Phase • Ascomycetes: Aspergillus,Histoplasma, Blastomyces, Dermatophytes • Basidiomycetes: Cryptococcus, Mushrooms • Zygomycetes: Order Mucorales - Mucor, Rhizopus • Deuteromycetes (Fungi Imperfecti): Sporothrix, Coccidioides, Candida

  16. Clinical Types of Fungal Infections

  17. Routes of Infection • Inhalation of spores – major factor • Inoculation of spores into skin • Disease by normal flora in compromised host (Candida) • Hypersensitivity • Contact with infected host (Dermatophytes) • Mycotoxins

  18. Laboratory Diagnosis of Fungal Infections • Microscopic Examination of tissues and body fluids • Gram stain • Giemsa • India Ink • Potassium hydroxide (KOH) wet prep • Hematoxylin and Eosin stain • Periodic-Acid Schiff stain (PAS) • Gomori-Methenamine Silver stain (GMS) • Mucicarmine or Alcian Blue stain

  19. Budding Yeast - Gram Stain Staphylococcus Candida

  20. Encapsulated Yeast - India Ink

  21. KOH Prep - Broad-base Budding Yeast

  22. H&E Stain - Budding Yeasts

  23. GMS Stain - Septate Hyphae

  24. Mucicarmine Stain - C. neoformans

  25. Histopathological Response to Fungal Infection • Acute pyogenic abscess (Candida) • Chronic granuloma formation (Histoplasma) • Chronic, localized dermal inflammation (Dermatophytes) • Mixed pyogenic and granulomatous inflammation (Blastomyces) • Blood vessel invasion with thrombosis and infarction (Mucor, Aspergillus) • Hypersensitivity without tissue reaction (allergic bronchopulmonary aspergillosis)

  26. Fungal Cultures • Utilize Sabouraud agar with antibiotics • Identification criteria • Temperature of growth • Rate of growth • Colonial and microscopic morphology • Sporulation pattern • Biochemical reactions (yeast)

  27. Fungal Serology • Generally poor and not as useful as in other pathogens such as viruses and bacteria, with some exceptions. • Cryptococcal antigen by latex agglutination: serum and CSF. • Coccidioides - early IgM response is useful for identification of acute primary disease - CSF IgG prognostic value. • Skin tests for DTH - problems: • Cross-reactivity. • High positive rate in endemic areas.

  28. Candidiasis • Clinical manifestations • Mucosal • Vaginitis • Esophagitis • Oral thrush • Cutaneous • Chronic mucocutaneous • Systemic • Fungemia • Hepato-spleenic • Endophthalmitis • Renal • Urinary tract

  29. Oral Candidiasis

  30. Wet Mount - Candidiasis

  31. Mucocutaneous Candidiasis

  32. Candida sp. Tissue GMS Stain

  33. Aspergillosis • Clinical manifestations • Pneumonia • Aspergilloma • Allergic bronchopulmonary • Disseminated multiorgan involvement

  34. Aspergilloma

  35. Allergic Bronchopulmonary Aspergillosis

  36. CNS Aspergillosis

  37. Aspergillus sp – GMS Stain

  38. Zygomycosis • Clinical manifestations • Sinusitis • Rhinocerebral • Pulmonary • Renal

  39. Rhinocerebral Mucormycosisin Diabetic Ketoacidosis

  40. Postmortem – Rhinocerebral Mucormycosis

  41. Non-septate Branching Hyphae (PAS)

  42. Histoplasmosis • Clinical manifestations • Most cases mild or sub-clinical pulmonary disease • Dissemination appears to be common • Pneumonia • Chronic progressive pulmonary (cavitary) • Histoplasmoma • Disseminated

  43. Histoplasmosis – Calcified Lesions

  44. Histoplasmosis- GMS

  45. Histoplasmosis – Bone Marrow H. capsulatum Histiocyte

  46. Histoplasma capsulatum In vitro In vivo

  47. Presumed Ocular Histoplasmosis • Thought to be a late stage of primary histoplasmosis. • Causes abnormal blood vessels – scar tissue. • Organism has not been found in eye. • Treated with laser surgery.

  48. Risk Factors for Endogenous Endophthalmitis

  49. Fungal Keratitis

  50. Chemotherapy • FDA approved • Polyenes (Amphotericin B, lipid encapsulated forms) • Azoles (fluconazole, itraconazole, ketoconazole, voriconazole) • Echinocandin (Caspofungin, Micafungin, Anidulafungin) • Nucleoside derivatives (5-flurocytosine) • Allyamines (Terbinafine) • Microtubule disruption (Griseofulvin) • Investigational • Nikkomycins (chitin synthase inhibitors) • Echinocandin/pnemocandin/lipopeptide class (inhibit glycan synthesis)

More Related