MYCOLOGY

MYCOLOGY The fungi are eukaryotic organisms growing as a mass of branching, interlacing filaments known as mycelium. Among the many thousands of fungi known, only about 300 can cause diseases in humans and animals. The fungi are eukaryotic organisms growing as a mass of branching, interlacing filaments known as mycelium. Among the many thousands of fungi known, only about 300 can cause diseases in humans and animals. Bacteria Bacteria plant plant

Comparison of fungi and bacteria featurefungibacteria diameter4um1um nucleusEukaryoticprokaryotic cytoplasmMitochondria and endoplasmic reticulum present Cell membraneSterols presentSterols absent Cell wallchitinpeptidoglycan sporesSexual and asexual spores for reproduction Endospores for survival, not for reproduction Thermal dimorphism yesNo metabolismRequire organic carbon; no obligate anaerobes May do not require organic carbon; many obligate anaerobes

Structure of fungi

Morphology Unicellular fungi Unicellular fungi Multicellular fungi Multicellular fungi Hypha: mycelium (vegetative, aerial or reproductive). Hypha: mycelium (vegetative, aerial or reproductive). Spores: asexual spore Spores: asexual spore a) Conidium （分生孢子） : a) Conidium （分生孢子） : macroconidium, microconidium. macroconidium, microconidium. b) Thallospore （叶状孢子） : b) Thallospore （叶状孢子） : blastospore （芽生）, chlamydospore （厚 膜）,arthrospore （关节）. blastospore （芽生）, chlamydospore （厚 膜）,arthrospore （关节）. c) Sporangiospore( 孢子囊孢子） c) Sporangiospore( 孢子囊孢子）

Unicellular fungi

Multicellular fungi

Hypha spore

Culture Sabouraud culture medium Sabouraud culture medium optimal pH 4-6 optimal pH 4-6 optimal temperature C some deep pathogenic fungi need 37 C, optimal temperature C some deep pathogenic fungi need 37 C, Aerobic Aerobic types of colonies – yeast, filamentous types of colonies – yeast, filamentous Multiplication:budding, hypha formation, branching or disruption of hypha, spore formation Multiplication:budding, hypha formation, branching or disruption of hypha, spore formation

Resistance Resistant to dry, sunlight, UV light and many chemicals Resistant to dry, sunlight, UV light and many chemicals Sensitive to wet heat Sensitive to wet heat

Clinical manifestations Clinical manifestations pathogenic fungal infection pathogenic fungal infection Opportunistic pathogenic fungal infection Opportunistic pathogenic fungal infection Fungal allergic diseases Fungal allergic diseases Mycotoxicosis Mycotoxicosis Mycotoxin and tumor Mycotoxin and tumor

Immunity Nonspecific immunity Nonspecific immunity Specific immunity Specific immunity

Microbiological diagnosis Specimens Specimens Direct smear Direct smear Isolation and cultivation Isolation and cultivation Serological tests. Serological tests.

Fungi of superficial keratinized infection Malassezia furfur （秕糠马拉 癣菌）. Malassezia furfur （秕糠马拉 癣菌）.

Fungi of skin infection The most important are dermatophytes, a group of closely fungi classified into 3 genera: The most important are dermatophytes, a group of closely fungi classified into 3 genera: Trichophyton （毛癣菌） Trichophyton （毛癣菌） Epidermophyton （表皮癣菌 0 Epidermophyton （表皮癣菌 0 Microsprum （小孢子癣菌） Microsprum （小孢子癣菌） Invade only skin, hair, and nails. Invade only skin, hair, and nails.

Fungi of subcutaneous infection Chromomycosis (caused by several species of black molds; Fonsecaea edrosoi, Cladosporium carrionii, Phialophora verrua have been isolated most frequently). Chromomycosis (caused by several species of black molds; Fonsecaea edrosoi, Cladosporium carrionii, Phialophora verrua have been isolated most frequently).

Fungi of deep infection Cryptococcus neoformans Cryptococcus neoformans Histoplasma capsulatum Histoplasma capsulatum Coccidioides immites Coccidioides immites ( 厌酷球孢子菌〕 ( 厌酷球孢子菌〕 Blastomyes dermatitides Blastomyes dermatitides （皮炎芽生菌〕 （皮炎芽生菌〕 Paracoccidiodes brasiliensis Paracoccidiodes brasiliensis （巴西副孢子菌〕 （巴西副孢子菌〕

Cryptococcus neoformans Oval, budding yeast surrounded by a wide polysaccharide capsule Oval, budding yeast surrounded by a wide polysaccharide capsule

Cryptococcus neoformans

cryptococcosis cryptococcosis No human to human transmission No human to human transmission Infection follows inhalation of the cell of C. neoformans, which, in nature, are thought to be small, allowing the organism to enter deep into the lung. Infection follows inhalation of the cell of C. neoformans, which, in nature, are thought to be small, allowing the organism to enter deep into the lung.

Opportunistic Mycoses Candida （假丝酵母菌） Candida （假丝酵母菌） Aspergillus （曲霉） Aspergillus （曲霉） Mucor （毛霉） Mucor （毛霉） Pneumocystis carinii( 卡氏肺孢菌） Pneumocystis carinii( 卡氏肺孢菌）

Candida albicans

Etiological agents C.albicans C.guilliermondi C.stellatoidea C.krusei C.tropicalis C.albicans C.guilliermondi C.stellatoidea C.krusei C.tropicalis C.glabratat C.parapsilosis C.viswanathii C.kefyr* C.lusitaniae C.glabratat C.parapsilosis C.viswanathii C.kefyr* C.lusitaniae

Clinical categories Cutaneous: intetrigo,paronychia,onychomycosis Cutaneous: intetrigo,paronychia,onychomycosis Mucocutaneous: perleche, thrush, perianal disease Mucocutaneous: perleche, thrush, perianal disease Chronic: mucocutaneous candidiasis, guanulomatous disease Chronic: mucocutaneous candidiasis, guanulomatous disease Systemic: fungemia,endocarditis,pulmonary infection,urinary tract infection, meningitis, endophthalmitis Systemic: fungemia,endocarditis,pulmonary infection,urinary tract infection, meningitis, endophthalmitis

Yeasts Round to oval, single cells which reproduce by budding

Yeasts Candida Cryptococcus

Candidiasis Candida albicans Candida albicans

Ecological Niche Candida Albicans Endogenous

Infections with Candida usually occur when there is some alteration in: Cellular immunity Cellular immunity Normal Flora Normal Flora Physiology Physiology

CANDIDIASIS Skin Skin Vaginitis Vaginitis Urinary tract Urinary tract Mucous membranes Mucous membranes Septicemia Septicemia Endocarditis Endocarditis Pneumonia Pneumonia

CANDIDIASIS The fourth most common nosocomial bloodstream infection.

Clinical Specimens Candida Sputum Sputum Scrapings from lesions Scrapings from lesions Blood smears Blood smears Vaginal discharge Vaginal discharge Urine Urine Feces Feces

Candida albicans

8-12 MICRONS

Pseudomycelium

GERM TUBES

GEOGRAPHIC OCCURENCE WORLDWIDE WORLDWIDE

Therapy Amphotericin B Amphotericin B Nystatin Nystatin Ketoconazole Ketoconazole Fluconazole Fluconazole Itraconazole Itraconazole

Cryptococcosis Cryptococcus neoformans

Cryptococcosis A sub-acute or chronic infection which may affect the lungs or skin but most commonly manifests as a meningitis A sub-acute or chronic infection which may affect the lungs or skin but most commonly manifests as a meningitis

Ecological Niche Cryptococcus neoformans pigeon droppings Chicken droppings

Specimen of choice Cerebrospinal fluid

GEOGRAPHICAL DISTRIBUTION WORLDWIDE WORLDWIDE

Clinical Specimens Cryptococcosis CSF Sputum Pus Biopsy material urine

Serological Tests Cryptococcosis Indirect fluorescent antibody Tube Agglutination Latex Agglutination (measures antigen)

Drugs of Choice Cryptococcosis 5-Fluorocytosine Amphotericin B