Cl ass mycology lectures No
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3rd cl ass mycology lectures No.1 
Mycology
1-Mycology: Study of fungi 2-Mycoses: fungal infections 3-Mytoxicosis- intoxicaton
Kingdom: Fungi More than 10 million species, but only ~400 human disease (*) Sexual Groups Ascomycota* Basidiomycota* Zygomycota* Chytridia Fungi Imperfecti* -Very few species are in a commensal relationship with humans - includes Candida albicans and Malasezia furfur -Diseases caused by fungi are usually accidental -Endogenous and Exogenous Sources -Increasing problem due to antibacterial & immunosuppressive agents -Molecular mechanisms of pathogenesis not well-defined. The 5 main groups 
1-Clean up oil spills 2-Remove cyanide in mining operations 3-Neutralize dioxins and pesticides 4-Produce organic acids, sugars 5-Manufacture other commercial products.
1-Size-diameter 4 um-------1um 2-Nucleus. 3-Cytoplasm 4-Cell membrane, Sterol---absent in bacteria 5- Cell wall, Chitin ----peptidoglycane 6-Thermal dimorphism. 7-Metabolism 
Fungal cell wall -Consists of chitin not peptidoglycan like bacteria. Thus fungi are insensitive to antibiotics as penicillins -Chitin is a polysaccharide composed of long chain of n-acetyleglucasamine. -Also the fungal cell wall contain other polysaccharide, B-glucan, which is the site of action of some antifungal drugs. Fungal cell membrane Consist of ergosterol rather than cholesterol like bacterial cell membrane. Ergosterol is the site of action of antifungal drugs, amphotericin B & azole group 
Atmospheric & carbon source requirements -Most fungi are obligatory aerobes, some are facultative anaerobes, but none are obligatory anaerobes. -All fungi require a performed organic source of carbon –association with decaying matter. Natural habitat The environment. Exception Candida albicans is part of normal human flora What is Medical Mycology ? Medical mycology is the study of mycoses of man and their etiologic agents. Mycoses are the diseases caused by fungi. Of the several thousands of species of fungi that are known, less than 100 are pathogenic to man. MYCOTIC diseases (Four Types)
PATHOGENIC FUNGI. NORMAL HOST
IMMUNOCOMPROMISED HOST . Opportunistic fungi - 300 species. In addition to those species which are generally recognized as pathogenic to man it is firmly established that under unusual circumstances of abnormal susceptibility of patient, or the traumatic implantation of the fungus, other fungi are capable of causing lesions. Those are called (Opportunistic Fungi.) These circumstances may be 1. A debilitating condition of the host, as Diabetes. 2. A concurrent disease such as leukemia. 3. Prolonged treatment with corticosteroids. 4.Immunosuppressive drugs or an antibiotic for long duration, PORTAL OF ENTRY 1-SKIN 2-HAIR 3-NAILS 4-RESPIRATORY TRACT 5-GASTROINTESTINAL TRACT 6-URINARY TRACT THE CLINICIAN MUST 1-COLONIZATION 2-FUNGEMIA 3-INFECTION COLONIZATION Multiplication of an organism at a given site without harm to the host, INFECTION Invasion and multiplication of organisms in body tissue resulting in local cellular injury. Morphology of Fungi 1. Filamentous fungi (molds) 2. Yeasts 3. Yeast-like fungi 4. Dimorphic fungi
1.The basic morphological elements of filamentous fungi are long branching filaments or hyphae, which intertwine to produce a mass of filaments or mycelium 2.Colonies are strongly adherent to the medium and unlike most bacterial colonies cannot be emulsified in water. 3. The surface of these colonies may be velvety, powdery, or may show a cottony aerial mycelium. 4. Pigmentation of the colony itself and of the underlying medium is frequently present. 
Colony Morphology  
Yeasts 1-These occur in the form of round or oval bodies which reproduce by the formation of buds known as blastospores. 2-Yeasts colonies resemble bacterial colonies in appearance and in consistency. 3-The only pathogenic yeast in medical mycology is Cryptococcus neoformans  
Yeast-Like 1.These are fungi which occur in the form of budding yeast-like cells and as chains of elongated unbranched filamentous cells which present the appearance of broad septate hyphae. these hyphae intertwine to form a pseudomycelium. 2. The yeast like fungi are grouped together in the genus Candida. Candida Colonies 
Thermally Dimorphic Fungi These are fungi which exhibit a filamentous mycelial morphology (saprophytic phase) when grown at room temperature 27oC, but have a typical yeast morphology (parasitic phase) inside the body and when grown at 37oC in the laboratory (e.g. Histoplasmosis Histoplasma capsulatum 27Ċ  
Histoplasma capsulatum 37Ċ  
- Medically Important Fungi 1-Deuteromycota- no sexual spores 2-Zygomycota- coenocytic fungi 3-Ascomycota-
4-Basidomycota
*Opportunistic mycoses* 1- Candidiasis 2- Aspergillosis, 3- Mucormycosis 4-Phycomycosis
B-cutaneous C-Subcutaneous. D-Systemic A-Superficial Fungal Infections - Skin Infections -limited to Stratum corneum -do not penetrate deeper tissues - No inflammation 1-Superficial mycoses -Black piedra -White piedra 2-Pityriasis versicolor. 3-tinea nigra B-Cutaneous Mycoses 1-Dermatophytoses 2-Dermatomycoses C-Subcutaneous Mycoses -Caused by trauma [puncture]and introduction of the fungus and bacteria. 1-Chromoblasomycosis 2-Phaeohypomycosis 3-Mycetoma 4-Sporotrichosis D-Systemic or Deep Mycoses 1-Histoplasmosis 2-Coccidiomycosis 3-Blastomycosis. 4-Cryptococcosis
1-Subacute respiratory infection 2-Acute infection 3-Severe disseminated infection 1-Systemic mycoses :subacute respiratory infection 1-Low fever 2-Non-productive cough 3-Mild & self-limiting 2-Systemic Mycoses: Acute infection 1- Productive cough 2-purulent sputum 3-pain in chest 4-Weight loss 5-night sweats 6-X-ray positive --one, many lesions -consolidation.
1-solitary, unicellular 2-reproduction via budding 3-rounded shape 4-moist & mucoid colonies
1-filamentous hyphae 2-hyphal formation 3-tips may be rounded 4-(conidia/spores ) Yüklə 37,54 Kb. Dostları ilə paylaş:
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