Presentation is loading. Please wait.

Presentation is loading. Please wait.

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

Similar presentations

Presentation on theme: "Dental / Optometry Fundamentals II Stephen A. Moser, Ph.D. 10/26/2011"— Presentation transcript:

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

2 Epidemiology Geography Transmission of infection 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 Functions and 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 on Sexual 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 Cutaneous
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

39 Rhinocerebral Mucormycosis in 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
Candidia species Central venous lines, neutropenia, abdominal surgery, intravenous drug abuse, broad-spectrum antibiotics Aspergillus species Neutropenia, endocarditis, intravenous drug abuse, pulmonary disease being treated with high dose steroids, organ and stem cell transplant. H. capsulatum C. immitis B. dermatitidis C. neoformans May accompany disseminated disease Fusarium species Neutopenia, intravenous drug abuse

49 Fungal Keratitis

50 Chemotherapy FDA approved Investigational
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)

51 Antifungal Drugs for Systemic Mycoses - Amphotericin B
Mode of Action Binds to ergosterol, increases membrane permeability resulting in leakage of cytoplasmic components and cell death – Fungicidal Spectrum of Activity Candida, Crypto, Aspergillus, Histo, Blasto, Cocci, etc Limitations Nephrotoxicity

52 Antifungal Drugs for Systemic Mycoses - Fluconazole
Mode of Action Prevents ergosterol synthesis by inhibiting the C-14 demethylation step (cytochrome P-450 rx) Fungistatic Spectrum of Activity Candida, Crypto, Trichsporonosis, dermatophytes Limitations Resistance in some Candida sp – krusei and glabrata Not effective for non-dermatophyte moulds.

53 Antifungal Drugs for Systemic Mycoses -Echinocandins
Mode of Action Prevents synthesis of beta 1,3-glucan required for cell wall. Fungistatic Spectrum of activity Aspergillus, Candida NOT effective against Cryptococcus, zygomycetes.

54 Early Diagnosis of Invasive Fungal Infections
Obstacles Because of Immunosuppression typical signs and symptoms of infection are frequently absent Few clinical features are uniquely specific for systemic fungal infection Sputum and blood cultures are frequently negative Invasive procedures May be necessary for definitive diagnosis Are often complicated in severely immunocompromised patient

55 Early Diagnosis of Invasive Fungal Infections (Continued)
Benefits Early diagnosis permits selection of a therapy of maximal effectiveness Early intervention with antifungal therapy may help decrease the high mortality rate associated with serious systemic mycoses

56 Major Areas Covered How fungi differ from bacteria
The major fungal infections The epidemiology of fungal infections Pathology of fungal infections Mechanism of action of antifungal agents

Download ppt "Dental / Optometry Fundamentals II Stephen A. Moser, Ph.D. 10/26/2011"

Similar presentations

Ads by Google