MYCOLOGYMYCOLOGY

MYCOLOGYMYCOLOGY

The fungi are eukaryotic organisms growiThe fungi are eukaryotic organisms growing as a mass of branching, interlacing filang as a mass of branching, interlacing filaments known as mycelium. Among the mments known as mycelium. Among the many thousands of fungi known, only abouany thousands of fungi known, only about 300 can cause diseases in humans and at 300 can cause diseases in humans and animals.nimals.

BacteriaBacteria plantplant

Comparison of fungi and Comparison of fungi and bacteriabacteria

feature fungi bacteria

diameter 4um 1um

nucleus Eukaryotic prokaryotic

cytoplasm Mitochondria and endoplasmic reticulum present

Mitochondria and endoplasmic reticulum present

Cell membrane Sterols present Sterols absent

Cell wall chitin peptidoglycan

spores Sexual and asexual spores for reproduction

Endospores for survival, not for reproduction

Thermal dimorphism

yes No

metabolism Require organic carbon; no obligate anaerobes

May do not require organic carbon; many obligate anaerobes

Structure of fungiStructure of fungi

MorphologyMorphology Unicellular fungiUnicellular fungi Multicellular fungiMulticellular fungi Hypha: mycelium (vegetative, aerial or reprodHypha: mycelium (vegetative, aerial or reprod

uctive).uctive). Spores: asexual sporeSpores: asexual spore a) Conidiuma) Conidium （分生孢子）（分生孢子） : : macroconidium, microconidium.macroconidium, microconidium. b) Thallosporeb) Thallospore （叶状孢子）（叶状孢子） : : blastosporeblastospore （芽生）（芽生） , chlamydospore, chlamydospore （厚（厚

膜）膜） ,arthrospore,arthrospore （关节）（关节） .. c) Sporangiospore(c) Sporangiospore( 孢子囊孢子）孢子囊孢子）

Unicellular fungiUnicellular fungi

Unicellular Unicellular fungifungi

Multicellular fungiMulticellular fungi

Multicellular fungiMulticellular fungi

Multicellular fungiMulticellular fungi

Hypha

•spore

Culture Culture

Sabouraud culture mediumSabouraud culture medium optimal pH 4-6optimal pH 4-6 optimal temperature 22-28 C some deep pathogoptimal temperature 22-28 C some deep pathog

enic fungi need 37 C, enic fungi need 37 C, AerobicAerobic types of colonies– yeast, filamentoustypes of colonies– yeast, filamentous Multiplication:budding, hypha formation, branMultiplication:budding, hypha formation, bran

ching or disruption of hypha, spore formation ching or disruption of hypha, spore formation

ResistanceResistance

Resistant to dry, sunlight, UV light and many Resistant to dry, sunlight, UV light and many chemicalschemicals

Sensitive to wet heatSensitive to wet heat

Clinical manifestationsClinical manifestations

pathogenic fungal infection pathogenic fungal infection Opportunistic pathogenic fungal infectionOpportunistic pathogenic fungal infection Fungal allergic diseasesFungal allergic diseases MycotoxicosisMycotoxicosis Mycotoxin and tumorMycotoxin and tumor

ImmunityImmunity

Nonspecific immunityNonspecific immunity Specific immunitySpecific immunity

Microbiological Microbiological diagnosisdiagnosis

SpecimensSpecimens Direct smearDirect smear Isolation and cultivationIsolation and cultivation Serological tests.Serological tests.

Fungi of superficial keratinized Fungi of superficial keratinized infection infection

Malassezia furfurMalassezia furfur （秕糠马（秕糠马拉癣菌）拉癣菌） ..

Fungi of skin infection Fungi of skin infection

The most important are dermatophytThe most important are dermatophytes, a group of closely fungi classified es, a group of closely fungi classified into 3 genera: into 3 genera:

TrichophytonTrichophyton （毛癣菌）（毛癣菌） Epidermophyton Epidermophyton （表皮癣菌（表皮癣菌 00 MicrosprumMicrosprum （小孢子癣菌）（小孢子癣菌） Invade only skin, hair, and nails.Invade only skin, hair, and nails.

Fungi of subcutaneous Fungi of subcutaneous infection infection

Chromomycosis (caused by several sChromomycosis (caused by several species of black molds; Fonsecaea edropecies of black molds; Fonsecaea edrosoi, Cladosporium carrionii, Phialophosoi, Cladosporium carrionii, Phialophora verrua have been isolated most frera verrua have been isolated most frequently).quently).

Fungi of deep infection Fungi of deep infection

Cryptococcus neoformans Cryptococcus neoformans Histoplasma capsulatumHistoplasma capsulatum Coccidioides immitesCoccidioides immites ( ( 厌酷球孢子菌〕厌酷球孢子菌〕 Blastomyes dermatitidesBlastomyes dermatitides （皮炎芽生菌〕（皮炎芽生菌〕 Paracoccidiodes brasiliensisParacoccidiodes brasiliensis （巴西副孢子菌〕（巴西副孢子菌〕

Cryptococcus neoformans Cryptococcus neoformans Oval , budding yeast surrounded Oval , budding yeast surrounded

by a wide polysaccharide capsuleby a wide polysaccharide capsule

Cryptococcus neoformansCryptococcus neoformans

Cryptococcus neoformansCryptococcus neoformans cryptococcosiscryptococcosis No human to human transmissionNo human to human transmission Infection follows inhalation of the ceInfection follows inhalation of the ce

ll of C. neoformans, which , in nature ll of C. neoformans, which , in nature , are thought to be small , allowing th, are thought to be small , allowing the organism to enter deep into the lune organism to enter deep into the lung.g.

Opportunistic MycosesOpportunistic Mycoses

CandidaCandida （假丝酵母菌）（假丝酵母菌） Aspergillus Aspergillus （曲霉）（曲霉） MucorMucor （毛霉）（毛霉） Pneumocystis carinii(Pneumocystis carinii( 卡氏肺孢菌） 卡氏肺孢菌）

Candida albicansCandida albicans

Etiological agentsEtiological agents

C.albicans C.guilliermondi C.stellatC.albicans C.guilliermondi C.stellatoidea C.krusei C.tropicalis oidea C.krusei C.tropicalis

C.glabratat C.parapsilosis C.viswanC.glabratat C.parapsilosis C.viswanathii C.kefyr* C.lusitaniaeathii C.kefyr* C.lusitaniae

Clinical categoriesClinical categories

Cutaneous: intetrigo,paronychia,onychomyCutaneous: intetrigo,paronychia,onychomycosiscosis

Mucocutaneous: perleche, thrush, perianal Mucocutaneous: perleche, thrush, perianal diseasedisease

Chronic: mucocutaneous candidiasis, guanChronic: mucocutaneous candidiasis, guanulomatous diseaseulomatous disease

Systemic: fungemia ,endocarditis,pulmonaSystemic: fungemia ,endocarditis,pulmonary infection,urinary tract infection, meningiry infection,urinary tract infection, meningitis, endophthalmitis tis, endophthalmitis

YeastsYeastsRound to oval, single cells which Round to oval, single cells which reproduce by budding reproduce by budding

YeastsYeasts

CandidaCryptococcus

CandidiasisCandidiasis

Candida albicansCandida albicans

Ecological Niche

Candida Albicans

Endogenous

Infections with Candida usually occInfections with Candida usually occur when there is some alteration in:ur when there is some alteration in:

Cellular immunityCellular immunity Normal FloraNormal Flora PhysiologyPhysiology

CANDIDIASISCANDIDIASIS

SkinSkin VaginitisVaginitis Urinary tract Urinary tract Mucous membranesMucous membranes SepticemiaSepticemia Endocarditis Endocarditis PneumoniaPneumonia

CANDIDIASISCANDIDIASISThe fourth most common nosocomial The fourth most common nosocomial

bloodstream infection.bloodstream infection.

Clinical SpecimensClinical SpecimensCandidaCandida

SputumSputum Scrapings from lesionsScrapings from lesions Blood smearsBlood smears Vaginal dischargeVaginal discharge UrineUrine FecesFeces

Candida albicansCandida albicans

8-12 MICRONS

Pseudomycelium

GERM TUBES

GEOGRAPHIC GEOGRAPHIC OCCURENCEOCCURENCE

WORLDWIDEWORLDWIDE

TherapyTherapy

Amphotericin BAmphotericin B NystatinNystatin KetoconazoleKetoconazole FluconazoleFluconazole ItraconazoleItraconazole

CryptococcosisCryptococcosisCryptococcus neoformansCryptococcus neoformans

CryptococcosisCryptococcosis

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

Ecological Niche

Cryptococcus neoformans

• pigeon droppings• Chicken droppings

Specimen of Specimen of choicechoice

Cerebrospinal fluidCerebrospinal fluid

GEOGRAPHICAL GEOGRAPHICAL DISTRIBUTIONDISTRIBUTION

WORLDWIDEWORLDWIDE

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