medical mycology

                                                                                        Dr.許明隆    11-24-2008

黴菌有關的角色   

1.    分解有機物 (腐生菌)

2.    提供食物，製造藥物 –

3.    致病

對植物--馬鈴薯疫病--引起饑荒 (愛爾蘭1846-50) starvation-> crop failure

愛爾蘭饑荒(Irish famine, patato blight)- (www.yahoo.com)

對人直接致病—medical mycology

 

Fungus related problems (medical mycology vs. gerneral mycology)

1. poisoning->     Mycotoxicosis (mycotoxin.. Aspergillus, Penicillium, Fusarium spp.)

e.g. aflatoxin 黃麴毒素 ( from Aspergillus flavus )--hepatoma肝癌

             ergot alkaloid (ergotism)- spoilage of stored food

          Mycetismus ( mushroom poisoning) e.g. Amanita phalloides鬼筆鵝膏�vamanitin, phalloidin )

                 reference: 讀者文摘 1989,9月 p33-38 '緊急移植手術 '

2. allergy-> Aspergillus (ABPA- allergic bronchopulmonary aspergillosis); farmer’s lung, asthma氣喘

3. infection- Mycoses

 

Fungi - general characteristics

*eukaryote, heterotrophic

*commonly called

                 yeasts                           blastomycetes

                 molds (具hyphae)�w       hyphomycetes

                 mushrooms

*subdivided into 4 important phyla-

                 zygomycota , ascomycota, basidiomycota, deuteromycota

*some are dimorphic

*geophilic, zoophilic, anthropophilic

*reproduce        asexually     or     sexually

                 Arthrospore           Ascospore # #

                 Blastospore           Basidiospore *

                 Chlamydospore     Zygospore *

                 Sporangiospore

*cell wall is composed primarily of polysaccharides (chitin..)

                 PAS stain- red,   GMS stain- black

*antifungals- amphotericin B, 5-FC, imidazole, ….(limited compared to antibiotics)

 

Medical Mycology---Mycoses

1. Superficial Mycoses

2. Cutaneous Mycoses                  Superficial fungal infection

3. Subcutaneous Mycoses             Deep fungal infection

4. Systemic Mycoses 

     Pathogenic fungi

     Opportunistic Mycoses

 

1.Superficial Mycoses            正常菌叢在易感的人發作                

          Tinea versicolor �v(汗斑) - Malassezia furfur

2.Cutaneous Mycoses ( Dermatophytoses)    癬 (ringworm)      皮屑經衣物/用具/環境接觸傳染

          Dermatophytes (皮癬菌)- involve skin, hair or nails

                   Trichophyton spp.- e.g. T. rubrum, T. mentagrophytes (兔), T. violaceum..

                   Microsporum spp.- e.g. M. canis. (貓,狗)*

                   Epidermophyton spp- e.g. Epidermophyton floccosum

          Tinea capitis          頭癬  (ectothrix *, endothrix *)

          Tinea corporis       體癬 

          Tinea cruris           股癬  (jock's itch)

          Tinea pedis *         足癬 (香港腳) (athlete's foot)

          Tinea unguium       甲癬 (灰指[趾]甲)  cf. Onychomycosis

 

3.Subcutaneous Mycoses- 土壤或腐木內的黴菌意外植入引起

          Sporotrichosis-      Sporothrix schenckii   (dimorphic)

          Chromomycosis- •— pigmented mold (dematiaceous spp.)引起

                   Chromoblastomycosis

                   Phaeohyphomycosis

          Mycetoma- 足菌腫

                   Eumycetoma ( Pseuallescheria boydii..)

                   Actinomycetoma ( Nocardia spp...)

                  三特徵 tumefaction, draining sinus, granules discharge

 

 4.Systemic Mycoses-   吸入感染

          Pathogenic fungi- endemic, America, acquired by inhalation

                             all are dimorphic fungi

                   Coccidioidomycosis (California's disease)�n

                   Histoplasmosis (Ohio valley disease)

                   Blastomycosis (North American Blastomycosis, Chicago's disease)

                   Paracoccidiodomycosis (South American Blastomycosis)

    Opportunistic Mycoses    伺機性黴菌感染(宿主抵抗力低時)

          Yeasts

                   Candidiasis- (Candidosis, Moniliasis)- Candida albicans 白色念珠菌

                             thrush (鵝口瘡), vulvovaginitis (外陰陰道炎), balanoposthitis(龜頭包皮炎)

                              * intertrigo (對磨疹-指間, 腋下, 胯下, 乳房下, 尿布疹)--之併發症

                             paronychia (甲溝炎) *

                             chronic mucocutaneous candidiasis

                   Cryptococcosis  隱球菌症

                             pigeon feces (鴿糞)- large amount of Cryptococcus neoformans

                             special affinity for CNS (導致腦膜炎 meningitis)

                            Indian Ink - contrast the polysaccharide capsules

          Molds

                   Aspergillosis-  A.fumigatus. A.flavus,

                             colonizing aspergillosis- aspergilloma

                             allergic aspergillosis

                             invasive aspergillosis

                   Zygomycosis (Phycomycosis, Mucormycosis)- Rhizopus

                                      all are rapid growers

                                      all have a predilection for invading blood vessels

                             diabetic patient especially with acidosis, extensive burn

                             nonseptate, broad hyphae with 900angle branching

                             rhinocerebral zygomycosis- most common form

 

Examination and Identification of Fungi

          10% KOH mount- septate hyphae, arthrospore, pseudohyphae, sclerotic body..

                             spaghetti and meat balls.

          Wood's light- bright yellow or green fluorescence. (Tinea capitis-Microsporum spp.)

          Fungal Culture- primary fungal culture

                   Sabouraud agar- for gross colony morphology

                   Mycobiotic agar (Mycosel agar) - add Chloramphenicol and Cycloheximide

          Slide culture - for genus or species identification (morphology identification )

          Germ tube test - for identification of Candica albicans