OPPORTUNISTIC MYCOSES

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OPPORTUNISTIC MYCOSES

• Sevtap Arikan, MD

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OPPORTUNISTIC MYCOSESGeneral features

• CAUSATIVE AGENTS
• Saprophyte in nature/found in normal flora
• HOST
• Immunosupressed /other risk factors

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OPPORTUNISTIC MYCOSES

• Candidiasis
• Cryptococcosis
• Aspergillosis
• Zygomycosis
• Other Trichosporonosis, fusariosis,
  penicillosis
• ANY fungus found in nature may give rise to
  opportunistic mycoses

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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

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MOST COMMONLY ISOLATED CANDIDA SPECIES

• C. albicans
• C. tropicalis
• C. parapsilosis
• C. kefyr
• C. glabrata
• C. krusei
• C. guillermondii
• C. lusitaniae

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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

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CandidaPATHOGENICITY

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

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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...

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CANDIDIASISClinical manifestations-I

• 1. CUTANEOUS and SUBCUTANEOUS
• Oral
• Vaginal
• Onychomycosis
• Dermatitis
• Diaper rash
• Balanitis

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CANDIDIASISClinical manifestations-II
2. SYSTEMIC

• Peritonitis
• Hepatosplenic
• Endophthalmitis
• Arthritis
• Osteomyelitis
• Menengitis
• Skin lesions

• Esophagitis
• Pulmonary inf.
• Cystitis
• Pyelonephritis
• Endocarditis
• Myocarditis

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CANDIDIASISClinical manifestations-III

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

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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)

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CANDIDIASISTreatment

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

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CRYPTOCOCCOSIS

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

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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 37C

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CRYPTOCOCCOSIS Clinical manifestations

• 1. PULMONARY
• Asymptomatic/flu-like/hilar lap/cavitation
• 2. DISSEMINATED
• Meningitis (acute/chronic)
• Cryptococcoma
• Skin lesions
• Other

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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

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CRYPTOCOCCOSIS Treatment

• Amphotericin B ( flucytosine)
• Life-long fluconazole prophylaxis following
  primary treatment (in AIDS patients)

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ASPERGILLOSIS

• Etio Aspergillus spp.(most commonA. 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 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

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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)
  

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ASPERGILLOSISClinical manifestations-II

• III. INVASIVE ASPERGILLOSIS
• 1. Pulmonary
• 2. Disseminated GIT, brain, liver,
  kidney, heart, skin, eye
• IV. MYCOTOXICOSIS

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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)

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ASPERGILLOSISTreatment

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

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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

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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

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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)

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ZYGOMYCOSIS Treatment

• Surgical debridement
• Amphotericin B
• High mortality rate