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OPPORTUNISTIC MYCOSES
Sevtap Arikan, MD
OPPORTUNISTIC MYCOSESGeneral features
CAUSATIVE AGENTSSaprophyte in nature/found in normal flora
HOST Immunosupressed /other risk
factors
Candidiasis Cryptococcosis Aspergillosis Zygomycosis Other: Trichosporonosis, fusariosis,
penicillosis……***ANY fungus found in nature may give
rise to opportunistic mycoses ***
OPPORTUNISTIC MYCOSES
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
CANDIDIASIS
MOST COMMONLY ISOLATED CANDIDA SPECIESC. albicansC. tropicalisC. parapsilosis C. kefyrC. glabrata C. kruseiC. guillermondiiC. lusitaniae
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
CandidaPATHOGENICITY Attachment (Germ tube is more
adhesive than yeast cell)Adherence to plastic surfaces
(catheter, prosthetic valve..)ProteasePhospholipase
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...
CANDIDIASISClinical manifestations-I1. CUTANEOUS and SUBCUTANEOUSOralVaginal OnychomycosisDermatitisDiaper rash Balanitis
CANDIDIASISClinical manifestations-II
Esophagitis Pulmonary inf. Cystitis Pyelonephritis Endocarditis Myocarditis
Peritonitis Hepatosplenic Endophthalmitis Arthritis Osteomyelitis Menengitis Skin lesions
2. SYSTEMIC
CANDIDIASISClinical manifestations-III3. CHRONIC MUCOCUTANEOUS Candida inf. of skin and mucous
membranes Verrucose lesions Impaired cellular immunity Autosomal recessive trait Hypoparathyroidism, iron deficiency
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)
CANDIDIASISTreatment CUTANEOUSTopical antifungal: Ketoconazole, miconazole, nystatin SYSTEMIC Amphotericin B Fluconazole, itraconazole CHRONIC MUCOCUTANEOUSAmphotericin BFluconazole, itraconazoleTransfer factor
CRYPTOCOCCOSIS
Underlying cellular immunodeficiency (AIDS, lymphoma)
Exogenous inf. Pathogenesis Inhalation of yeasts Etio. Cryptococcus neoformans
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. Capsuleb. Diphenol oxidase (+) (Bird seed
agar/ caffeic acid medium)c. Ability to grow at 37°C
CRYPTOCOCCOSIS Clinical manifestations1. PULMONARYAsymptomatic/flu-like/hilar lap/cavitation2. DISSEMINATED**Meningitis (acute/chronic)CryptococcomaSkin lesionsOther
CRYPTOCOCCOSIS DiagnosisSamples CSF, sputum,
aspiration from skin lesion
Direct 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)
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
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
ASPERGILLOSISClinical manifestations-I
I. 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
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)
ASPERGILLOSISTreatment ALLERGIC Steroid ASPERGILLOMA (if symptomatic)
Surgery, amphotericin B LOCAL, SUPERFICIAL INF. Nystatin INVASIVE INF.
Surgical debridementAmphotericin B, itraconazole***High mortality rate
ZYGOMYCOSIS
Causative agentsRhizopus, Rhizomucor, Mucor...
Natural reservoir Air, water, soil Risk factors Diabetic ketoacidosis,
immunosuppression Pathogenesis Inhalation of sporangiospores Infected tissue vascular invasion,
thrombus, infarct, bleeding
ZYGOMYCOSISClinical manifestationsI. RHINOCEREBRAL Nose, paranasal sinuses, eye, brain and
meninges are involved Orbital cellulitis II. THORACIC Pulmonary lesions, parenchymal necrosisIII. LOCAL Posttraumatic kidney inf. Skin inf. following burn or surgery
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)
ZYGOMYCOSIS Treatment
Surgical debridement
Amphotericin B
***High mortality rate