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