OPPORTUNISTIC MYCOSES

OPPORTUNISTIC MYCOSESGeneral featuresCAUSATIVE AGENTSSaprophyte in nature/found in normal flora

HOST Immunosupressed /other risk factors

CandidiasisCryptococcosisAspergillosisZygomycosisOther: Trichosporonosis, fusariosis, penicillosis***ANY fungus found in nature may give rise to opportunistic mycoses ***

OPPORTUNISTIC MYCOSES

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

MOST COMMONLY ISOLATED CANDIDA SPECIESC. albicansC. tropicalisC. parapsilosis C. kefyrC. glabrata C. kruseiC. guillermondiiC. lusitaniae

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

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

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...

CANDIDIASISClinical manifestations-I1. CUTANEOUS and SUBCUTANEOUSOralVaginal OnychomycosisDermatitisDiaper rash Balanitis

CANDIDIASISClinical manifestations-IIEsophagitisPulmonary inf.CystitisPyelonephritisEndocarditisMyocarditis

PeritonitisHepatosplenicEndophthalmitis ArthritisOsteomyelitisMenengitisSkin lesions2. SYSTEMIC

CANDIDIASISClinical manifestations-III3. CHRONIC MUCOCUTANEOUSCandida inf. of skin and mucous membranes Verrucose lesionsImpaired cellular immunityAutosomal recessive traitHypoparathyroidism, iron deficiency

CANDIDIASISDiagnosisDirect micr.ic examination Yeast cells, pseudohyphae, true hyphaeCulture SDA, routine bacteriological mediaSerology Detection of mannan antigen (ELISA, RIA, IF, latex agglutination)

CANDIDIASISTreatmentCUTANEOUSTopical antifungal: Ketoconazole, miconazole, nystatinSYSTEMIC Amphotericin B Fluconazole, itraconazoleCHRONIC MUCOCUTANEOUSAmphotericin BFluconazole, itraconazoleTransfer factor

CRYPTOCOCCOSISUnderlying cellular immunodeficiency (AIDS, lymphoma) Exogenous inf.Pathogenesis Inhalation of yeasts Etio. Cryptococcus neoformans

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

CRYPTOCOCCOSIS Clinical manifestations1. PULMONARYAsymptomatic/flu-like/hilar lap/cavitation2. DISSEMINATED**Meningitis (acute/chronic)CryptococcomaSkin lesionsOther

CRYPTOCOCCOSIS DiagnosisSamples CSF, sputum, aspiration from skin lesionDirect exam. India inkCulture SDASerology*** Detection of capsule antigen in CSF and serum by latex agglutination test

CRYPTOCOCCOSIS Treatment

Amphotericin B (+ flucytosine)

Life-long fluconazole prophylaxis following primary treatment (in AIDS patients)

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

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

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)

ASPERGILLOSISClinical manifestations-IIIII. INVASIVE ASPERGILLOSIS1. Pulmonary2. Disseminated: GIT, brain, liver, kidney, heart, skin, eye

IV. MYCOTOXICOSIS

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)

ASPERGILLOSISTreatmentALLERGIC SteroidASPERGILLOMA (if symptomatic) Surgery, amphotericin B LOCAL, SUPERFICIAL INF. NystatinINVASIVE INF.Surgical debridementAmphotericin B, itraconazole***High mortality rate

ZYGOMYCOSISCausative agentsRhizopus, Rhizomucor, Mucor...Natural reservoir Air, water, soilRisk factors Diabetic ketoacidosis, immunosuppressionPathogenesis Inhalation of sporangiosporesInfected tissue vascular invasion, thrombus, infarct, bleeding

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

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)

ZYGOMYCOSIS Treatment

Surgical debridement

Amphotericin B

***High mortality rate