By Dr- Tamer Bedir Microbiology and Medical Immunology Dept.

Systemic mycosis - It is a group of fungal diseases in which fungi disseminated by blood (fungemia) to infect many organs in the body - can be divided into 2 groups A- opportunistic mycosis - candidiasis - aspergillosis - cryptococcosis B- endemic mycosis a. histoplasmosis b. blastomycosis

Candidal infection It is fungal infection caused by one member of genus Candida. Source of infection: Endogenous: (autoinfection): Present as normal flora in oral cavity, GIT, female genital tract and skin (the most common source). Exogenous: By contact.

Predisposing factors 1. Extreme of age. 2. Pregnancy and diabetes. 3. Prolonged use of antibiotics, steroids or immunosuppressive drugs. 4. Traumatic conditions such as catheter or IV lines. 5. HIV 6. Tumors, radiotherapy and cheotherapy

Non-albicans Candida 1. Candida tropicalis. 2. Candida glaborata.  Resist azole antifungal agents  Cause nosocomial infections

Clinical manifestation of diseases caused by Candida A- Mucocutaneous infection: 1. Oral thrush: In the mouth (cheesy covering layer), mouth angles: (stomatitis), at the lips (cheilitis), glossitis. 2. Vaginitis: White-milky discharge and itching. 3. Oesophageal candidiasis especially in HIV pts 4. Chronic mucocutanous candidiasis: with polyendocrinopathies with T cell defect

B- Cutaneous infections: 1. Skin: Napkin area in baby, axilla, groin, submammary folds, characterized by redness, itching and red follicles. 2. Nail: Paronychia and onychomycosis. C- Systemic infections: 1.. Urinary tract infection. 2. Endocarditis. 3. brain abscess, renal abscess. 4. Septicemia, fungemia

Oral thrush

Napkin dermatitis

Paronychia

Laboratory diagnosis of Candidiasis A. Direct: Sample: oral swab, mid stream urine, blood……. 1. Direct Microscopic examination:  Unstained preparation or stained preparation (KOH) lactophenol-cotton blue stains.  For detection of yeast cells and pseudohyphae.

Candida albicans SEM

2. Culture:  On SDA medium: the colonies after 24 – 48 hours are white, smooth, creamy and have characteristic yeast odour.  Growth is identified by: a. film stained with LPCB: Spherical or oval cells. Gram film shows Gram-positive yeast. b. Microculture: Rice agar plates for demonstration of chlamydospores.

Candida Colonies

c. Biochemical reactions: Sugar fermentation and assimilation. d. Germ tube formation: The ability of Candida albicans to form filamentous growth after 2 – 4 hours when cultivated on human serum at 37ºC (rapid sure diagnosis). e. Chlamydospores formation on Potato Carrot Bile medium.

Chlamydiospore

B. Indirect: 1. Serological test: Ag detection (β glucan): Important in immunocompromized patients. 2. Histopathology: Diagnostic element is Yeast cell & Pseudohyphae. 3. New tests for diagnosis:  PCR.  Biofilm by scanning electron microscope

Treatment 1. Superficial: Topical polyene as nystatin. Topical imidazole as micnazole. 2. Deep systemic infection: Amphotericin B. Fluconazole (1 st step treatment) especially for candida albicans. Caspofungin. Lipid preparation; liposomal Amphotericin B.

B. Cryptococcus neoformans Morphology: Capsulated yeast. Urease positive. Epidemiology: Source of infection: Pigeon or birds droppings and soil contaminated with them. Human infection mostly by inhalation. No case-to-case transmission.

Clinical picture: Pneumonia followed by meningitis. In heavy infection disseminated skin and bone infections occur.

Diagnosis: In Cryptococcus meningitis: CSF shows 1. Increased pressure of CSF. 2. Decreased glucose and increased protein. 3. Increased cell count > 100, mostly lymphocytes. 4. Indea ink preparation: yeast cell surrounded by huge capsule. Culture and identification of growth. Detection of Cryptococcus antigen in CSF by latex agglutination.

Cryptococcus neoformans

Treatment: Amphotericin B. Followed by fluconazole (Can cross blood brain barrier) + 5 flucytosin.

C. Aspergillosis It is the fungal infection by Aspergillus. It is a saprophytic organism. Produces spores carried by air. Aspergillosis can produced in immunocompromized patients as well as immunocompetent persons. Causes: A. fumigatus, A. niger, and A. flavus.

Clinical forms 1. Granulomatous lesion: Chronic infection in the lung. 2. Fungal ball in old TB cavity: mass formation in the lung, which mistake by bronchogenic carcinoma. 3. Allergic type: Asthma and farmer's lung. 4. Acute pneumonia in immunocompromized patients.

Mode of transmission Environmentally by inhalation of spores. Diagnosis 1. KOH preparation of sputum: Hyaline, septated hyphae or dichotomously branched hyphae. 2. Culture on SDA and examination of growth by: A. Macroscopically: Black (A. niger), green-orange or white colonies. B. Microscopically: aspergillus head

Treatment  Antifungal drugs in disseminated lesions like: Amphotericin B, Itraconazole, Voriconazole.  Surgical removal of fungal ball.

II- Endemic Mycosis Def: group of fungal disease which is associated with special geographic and acquired from contact with nature source or inhalation of spores Caused by thermally dimorphic fungi which are 1ry pathogen and can infect both immunocompitant person producing minimal C/P immunocompromised persons → 1ry pulmonary infection then disseminate Difficult to be diagnosed after leaving the endemic area to non endemic area

II- Endemic Mycosis Blastomycetes dermatidis (north America (Mississippi river valley ) Histoplasma capsulatum (north America &Mexico &central & south America Coccidiodes immitis (south-western US Mexico & central & south America Paracoccidiodes brasilienesis (central & south America) penicillum marneffei → South-east & far east Asia as affect resident & traveler to endemic areas as Thailand

Clinical picture 1.pulmonary infection which may be asymptomatic or mild in immuno-comptent pts but may be sever and necrotizing in immunocompromised pts followed by dissemination 2. dissemination to CNS & bone & joint & soft tissue as LN, liver, spleen,… 3. the fungus may be dormant or latent for long time → reactivation (endogenous source) when cell mediated immunity decrease ↓

Diagnosis sample : sputum & broncho-alveolar lavage & lung biopsy & blood (buffy coat) & CSF & tissue exudates aspiration & bone marrow aspiration direct examination : tissue form by lactophenol blue or calcflower white or Geimsa or Leishman stain (yeast with bud) culture & identification of fungal growth : conversion from hyhae with spores form at 25C to yeast cell with bud at 37 C is necessary for definitive identification seo-diagnosis: detection of Ag and Ab but less sensitive and specific due to cross reaction

Treatment itraconazole for mild & moderate cases amphotricin B for sever cases or life threatening infection in meningitis fluconazole is alternative as cross blood brain barrier

Histoplasma capsulatum 37oc

Histoplasma capsulatum 27oC

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