opp mycoses 02
DESCRIPTION
MYCOSISTRANSCRIPT
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OPPORTUNISTIC MYCOSES
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OPPORTUNISTIC MYCOSESGeneral featuresCAUSATIVE AGENTSSaprophyte in nature/found in normal flora
HOST Immunosupressed /other risk factors
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CandidiasisCryptococcosisAspergillosisZygomycosisOther: Trichosporonosis, fusariosis, penicillosis***ANY fungus found in nature may give rise to opportunistic mycoses ***
OPPORTUNISTIC MYCOSES
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Most commonly encountered opportunistic mycoses worldwideCellular immunity protects against mucocutaneous candidiasis, neutrophiles protect against invasive candidiasisEndogenous inf. Etio: Candida spp. Most common: 1. C. albicans 2. C. tropicalis
CANDIDIASIS
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MOST COMMONLY ISOLATED CANDIDA SPECIESC. albicansC. tropicalisC. parapsilosis C. kefyrC. glabrata C. kruseiC. guillermondiiC. lusitaniae
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CandidaMORPHOLOGICAL FEATURES Micr. Budding yeast cells Pseudohyphae, true hyphaeMacr. Creamy yeast colonies (SDA)Germ tube(C. albicans, C. dubliniensis)Chlamydospore (C. albicans, C. dubliniensis)Identification Germ tube, fermentation and assimilation reactions
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CandidaPATHOGENICITY Attachment (Germ tube is more adhesive than yeast cell)Adherence to plastic surfaces (catheter, prosthetic valve..)ProteasePhospholipase
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CANDIDIASISRisk factorsPhysiological. Pregnancy, elderly, infancy Traumatic. Burn, infection Hematological. Cellular immune deficiency, AIDS, chronic granulamatous disease, aplastic anemia, leukemia, lymphoma...Endocrinological. DM, hypoparathyroidism, Addison diseaseIatrogenic. Oral contraceptives, antibiotics, steroid, chemotherapy, catheter...
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CANDIDIASISClinical manifestations-I1. CUTANEOUS and SUBCUTANEOUSOralVaginal OnychomycosisDermatitisDiaper rash Balanitis
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CANDIDIASISClinical manifestations-IIEsophagitisPulmonary inf.CystitisPyelonephritisEndocarditisMyocarditis
PeritonitisHepatosplenicEndophthalmitis ArthritisOsteomyelitisMenengitisSkin lesions2. SYSTEMIC
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CANDIDIASISClinical manifestations-III3. CHRONIC MUCOCUTANEOUSCandida inf. of skin and mucous membranes Verrucose lesionsImpaired cellular immunityAutosomal recessive traitHypoparathyroidism, iron deficiency
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CANDIDIASISDiagnosisDirect micr.ic examination Yeast cells, pseudohyphae, true hyphaeCulture SDA, routine bacteriological mediaSerology Detection of mannan antigen (ELISA, RIA, IF, latex agglutination)
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CANDIDIASISTreatmentCUTANEOUSTopical antifungal: Ketoconazole, miconazole, nystatinSYSTEMIC Amphotericin B Fluconazole, itraconazoleCHRONIC MUCOCUTANEOUSAmphotericin BFluconazole, itraconazoleTransfer factor
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CRYPTOCOCCOSISUnderlying cellular immunodeficiency (AIDS, lymphoma) Exogenous inf.Pathogenesis Inhalation of yeasts Etio. Cryptococcus neoformans
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Cryptococcus neoformansGeneral propertiesNatural reservoir Soil, bird droppingsMicr. Encapsulated yeast (India ink)Macr. Creamy, mucoid colonies (SDA)Serotypes A-D (most frequently A)Pathogenicity factors a. Capsuleb. Diphenol oxidase (+) (Bird seed agar/ caffeic acid medium)c. Ability to grow at 37C
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CRYPTOCOCCOSIS Clinical manifestations1. PULMONARYAsymptomatic/flu-like/hilar lap/cavitation2. DISSEMINATED**Meningitis (acute/chronic)CryptococcomaSkin lesionsOther
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CRYPTOCOCCOSIS DiagnosisSamples CSF, sputum, aspiration from skin lesionDirect exam. India inkCulture SDASerology*** Detection of capsule antigen in CSF and serum by latex agglutination test
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CRYPTOCOCCOSIS Treatment
Amphotericin B (+ flucytosine)
Life-long fluconazole prophylaxis following primary treatment (in AIDS patients)
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ASPERGILLOSISEtio: 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
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Aspergillus GENERAL FEATURESNatural reservoir: air, soilPathogenicity factors: hypha, phospholipaseInfected 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
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ASPERGILLOSISClinical manifestations-II. ALLERGIC ASPERGILLOSIS1. Asthma (Type I)2. Allergic bronchopulmonary aspergillosis (Types I, III)II. NONINVASIVE LOCAL COLONIZATION1. Aspergilloma (Fungus ball) (lungs, paranasal sinuses)2. Otomycosis (external otitis)3. Onychomycosis 4. Eye inf. (conjunctival, corneal, intraocular)
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ASPERGILLOSISClinical manifestations-IIIII. INVASIVE ASPERGILLOSIS1. Pulmonary2. Disseminated: GIT, brain, liver, kidney, heart, skin, eye
IV. MYCOTOXICOSIS
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ASPERGILLOSISDiagnosisSamples Sputum, BAL, tissue...Direct exam. Septate hyphae and conidia in sputum; intravascular hyphae in tissueCulture SDA (without cycloheximide) (should grow at least in 2 cultures !) SerologyAllergy (detection of specific IgE in serum--RAST)Invasive inf. (detection of galaktomannan antigen in serum--ELISA)
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ASPERGILLOSISTreatmentALLERGIC SteroidASPERGILLOMA (if symptomatic) Surgery, amphotericin B LOCAL, SUPERFICIAL INF. NystatinINVASIVE INF.Surgical debridementAmphotericin B, itraconazole***High mortality rate
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ZYGOMYCOSISCausative agentsRhizopus, Rhizomucor, Mucor...Natural reservoir Air, water, soilRisk factors Diabetic ketoacidosis, immunosuppressionPathogenesis Inhalation of sporangiosporesInfected tissue vascular invasion, thrombus, infarct, bleeding
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ZYGOMYCOSISClinical manifestationsI. RHINOCEREBRALNose, paranasal sinuses, eye, brain and meninges are involvedOrbital cellulitis II. THORACICPulmonary lesions, parenchymal necrosisIII. LOCALPosttraumatic kidney inf.Skin inf. following burn or surgery
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ZYGOMYCOSIS DiagnosisSamples Sputum, BAL, biopsy of paranasal sinuses..
Direct exam. Nonseptate, ribbon-like hyphae which branch at right angles, sporangium
Culture SDA (cotton candy appearence)
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ZYGOMYCOSIS Treatment
Surgical debridement
Amphotericin B
***High mortality rate