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OPPORTUNISTIC MYCOSES

OPPORTUNISTIC MYCOSES. Sevtap Arikan, MD. OPPORTUNISTIC MYCOSES General features. CAUSATIVE AGENTS Saprophyte in nature/found in normal flora HOST Immunosupressed /other risk factors. OPPORTUNISTIC MYCOSES. Candidiasis Cryptococcosis Aspergillosis Zygomycosis

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OPPORTUNISTIC MYCOSES

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  1. OPPORTUNISTIC MYCOSES Sevtap Arikan, MD

  2. OPPORTUNISTIC MYCOSESGeneral features CAUSATIVE AGENTS Saprophyte in nature/found in normal flora HOST Immunosupressed /other risk factors

  3. OPPORTUNISTIC MYCOSES • Candidiasis • Cryptococcosis • Aspergillosis • Zygomycosis • Other: Trichosporonosis, fusariosis, penicillosis…… ***ANY fungus found in nature may give rise to opportunistic mycoses ***

  4. CANDIDIASIS • Most commonly encountered opportunistic mycoses worldwide • Cellular immunity protects against mucocutaneous candidiasis, neutrophiles protect against invasive candidiasis • Endogenous inf. • Etio:Candida spp. Most common: 1. C. albicans 2. C. tropicalis

  5. MOST COMMONLY ISOLATED CANDIDA SPECIES • C.albicans • C. tropicalis • C. parapsilosis • C. kefyr • C. glabrata • C. krusei • C. guillermondii • C. lusitaniae

  6. CandidaMORPHOLOGICAL FEATURES • Micr. Budding yeast cells Pseudohyphae, true hyphae • Macr. Creamy yeast colonies (SDA) • Germ tube (C. albicans, C. dubliniensis) • Chlamydospore (C. albicans, C. dubliniensis) • Identification Germ tube, fermentation and assimilation reactions

  7. CandidaPATHOGENICITY • Attachment (Germ tube is more adhesive than yeast cell) • Adherence to plastic surfaces (catheter, prosthetic valve..) • Protease • Phospholipase

  8. CANDIDIASISRisk factors • Physiological. Pregnancy, elderly, infancy • Traumatic. Burn, infection • Hematological. Cellular immune deficiency, AIDS, chronic granulamatous disease, aplastic anemia, leukemia, lymphoma... • Endocrinological. DM, hypoparathyroidism, Addison disease • Iatrogenic. Oral contraceptives, antibiotics, steroid, chemotherapy, catheter...

  9. CANDIDIASISClinical manifestations-I 1.CUTANEOUS and SUBCUTANEOUS • Oral • Vaginal • Onychomycosis • Dermatitis • Diaper rash • Balanitis

  10. Esophagitis Pulmonary inf. Cystitis Pyelonephritis Endocarditis Myocarditis Peritonitis Hepatosplenic Endophthalmitis Arthritis Osteomyelitis Menengitis Skin lesions CANDIDIASISClinical manifestations-II 2.SYSTEMIC

  11. CANDIDIASISClinical manifestations-III 3. CHRONIC MUCOCUTANEOUS • Candida inf. of skin and mucous membranes • Verrucose lesions • Impaired cellular immunity • Autosomal recessive trait • Hypoparathyroidism, iron deficiency

  12. CANDIDIASISDiagnosis • Direct micr.ic examination Yeast cells, pseudohyphae, true hyphae • Culture SDA, routine bacteriological media • Serology Detection of mannan antigen (ELISA, RIA, IF, latex agglutination)

  13. CANDIDIASISTreatment • CUTANEOUS Topical antifungal: Ketoconazole, miconazole, nystatin • SYSTEMIC Amphotericin B Fluconazole, itraconazole • CHRONIC MUCOCUTANEOUS Amphotericin B Fluconazole, itraconazole Transfer factor

  14. CRYPTOCOCCOSIS • Underlying cellular immunodeficiency (AIDS, lymphoma) • Exogenous inf. • Pathogenesis Inhalation of yeasts • Etio.Cryptococcus neoformans

  15. Cryptococcus neoformansGeneral properties • Natural reservoir Soil, bird droppings • Micr. Encapsulated yeast (India ink) • Macr. Creamy, mucoid colonies (SDA) • Serotypes A-D (most frequently A) • Pathogenicity factors a. Capsule b. Diphenol oxidase (+) (Bird seed agar/ caffeic acid medium) c. Ability to grow at 37°C

  16. CRYPTOCOCCOSIS Clinical manifestations 1.PULMONARY Asymptomatic/flu-like/hilar lap/cavitation 2.DISSEMINATED **Meningitis (acute/chronic) Cryptococcoma Skin lesions Other

  17. CRYPTOCOCCOSIS Diagnosis • Samples CSF, sputum, aspiration from skin lesion • Direct exam. India ink • Culture SDA • Serology*** Detection of capsule antigen in CSF and serum by latex agglutination test

  18. CRYPTOCOCCOSIS Treatment • Amphotericin B (+ flucytosine) • Life-long fluconazole prophylaxis following primary treatment (in AIDS patients)

  19. ASPERGILLOSIS Etio: Aspergillus spp.(most common:A. fumigatus) Risc factors and pathogenesis 1. Immunosupression, DM..exogenous inf. (inhalation of spores) 2. Inhalation of spores by atopic host Hypersensitivity reactions (allergy) 3. Ingestion of products contaminated with Aspergillus toxins  Mycotoxicosis / hepatocellular and colon carcinoma

  20. Aspergillus GENERAL FEATURES • Natural reservoir: air, soil • Pathogenicity factors: hypha, phospholipase • Infected tissue: vascular invasion, thrombus, infarct, bleeding • Macr: powdery mould colonies (color of the spores varies from one species to other) • Micr: septate hyphae (dichotomous branching), vesicule, phialides, microconidia

  21. ASPERGILLOSISClinical manifestations-I I.ALLERGIC ASPERGILLOSIS 1. Asthma (Type I) 2. Allergic bronchopulmonary aspergillosis (Types I, III) II.NONINVASIVE LOCAL COLONIZATION 1. Aspergilloma (Fungus ball) (lungs, paranasal sinuses) 2. Otomycosis (external otitis) 3. Onychomycosis 4. Eye inf. (conjunctival, corneal, intraocular)

  22. ASPERGILLOSISClinical manifestations-II III. INVASIVE ASPERGILLOSIS 1. Pulmonary 2. Disseminated: GIT, brain, liver, kidney, heart, skin, eye IV. MYCOTOXICOSIS

  23. ASPERGILLOSISDiagnosis • Samples Sputum, BAL, tissue... • Direct exam. Septate hyphae and conidia in sputum; intravascular hyphae in tissue • Culture SDA (without cycloheximide) (should grow at least in 2 cultures !) • Serology Allergy (detection of specific IgE in serum--RAST) Invasive inf. (detection of galaktomannan antigen in serum--ELISA)

  24. ASPERGILLOSISTreatment • ALLERGIC Steroid • ASPERGILLOMA (if symptomatic) Surgery, amphotericin B • LOCAL, SUPERFICIAL INF. Nystatin • INVASIVE INF. Surgical debridement Amphotericin B, itraconazole ***High mortality rate

  25. ZYGOMYCOSIS • Causative agents Rhizopus, Rhizomucor, Mucor... • Natural reservoir Air, water, soil • Risk factors Diabetic ketoacidosis, immunosuppression • Pathogenesis Inhalation of sporangiospores • Infected tissue vascular invasion, thrombus, infarct, bleeding

  26. ZYGOMYCOSISClinical manifestations I. RHINOCEREBRAL • Nose, paranasal sinuses, eye, brain and meninges are involved • Orbital cellulitis II. THORACIC • Pulmonary lesions, parenchymal necrosis III. LOCAL • Posttraumatic kidney inf. • Skin inf. following burn or surgery

  27. ZYGOMYCOSIS Diagnosis • Samples Sputum, BAL, biopsy of paranasal sinuses.. • Direct exam. Nonseptate, ribbon-like hyphae which branch at right angles, sporangium • Culture SDA (cotton candy appearence)

  28. ZYGOMYCOSIS Treatment • Surgical debridement • Amphotericin B ***High mortality rate

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