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Medical Mycology.

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Presentation on theme: "Medical Mycology."— Presentation transcript:

1 Medical Mycology

2 Mycology Study of fungi Fungi found every where

3 Fungi (fungus) Fungi first appeared approximately 1.5 billion years ago 100, 000 known fungal species Estimated number 1 to 10 million fungal species 1000 to 1500 new species every year

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6 Fungal mycelium

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8 Fungi and disease The vast majority of fungi are not associated with disease, and many are saprophytic Around 500 species are associated with human and animal infections Plant fungal pathogens both destroy crops and generate mycotoxins Others cause disease in animals, such as the chytrid species Batrachochytrium dendrobatidis, which is devastating the global amphibian population

9 Fungal infections are becoming more important!!
Human fungal diseases became a serious problem only during the 20th and 21st centuries Increased efficiency in treating bacterial infections Growth in the number immunodeficient patients Increasing use of indwelling medical devices

10 Most important The most common human fungal pathogens are:
Candida albicans Cryptococcus neoformans Aspergillus fumigatus

11 Where are fungi? The 5 Kingdoms or Phyla system
Bacteria (heterophilic) Protista (unicellular) Animalia Fungi (heterophilic) Plantae (photosynthesis)

12 Main characteristics of fungi
DNA in nucleus, chromosomes Mitosis and meiosis Mitochondria Chitin and glucan in cell wall In sensitive to antibiotics

13 Morphology of fungi? Fungi can exist as single cells (yeast)
Or chains of cells (hyphae)

14 Morphology Filamentous Yeast Dimorphic

15 Physiology Temperature Nutrition Respiration Reproduction

16 Filamentous culture

17 Multicellular filamentous mould

18 Genus Aspergillus

19 Hyphal elongation and branching
Germination Spores inhaled Hyphal elongation and branching Mass of hyphae

20 Aspergillus species Aspergillus fumigatus Aspergillus flavus
Aspergillus niger Aspergillus nidulans Aspergillus terreus

21 Culture of Candida yeast

22 Yeast gram stain

23 Yeast fungus Filamentous fungus

24 Dimorphic fungus in brain tissue

25 Where do fungi live?

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27 Helpful fungi: In every day life
Nitrogen and Carbon Mushrooms and Quorn Saccharomyces cerevisiae Aspergillus oryzae and Aspergillus niger Flavours and vitamins Penicillin and cyclosporine Molecular cloning and cancer research Cephalosporins Griseofulvin (Penicillium griseofulvum) Lovastatin (Aspergillus terreus)

28 Fungi of Medical Importance
Section two Fungi of Medical Importance

29 Fungal infections Caused by only ≈ 500 species out of 100,000
Primary infections Opportunistic infections Myco-toxins Allergy

30 Mycoses Superficial and cutaneous Subcutaneous Deep (systemic)

31 Examples of yeast of medical importance
Candida species Germ tube test Cycloheximide susceptibility Growth at 45° C Cryptococcus neoformans Capsulated yeast → India Ink staining Malassezia species Lipophilic → media supplemented with lipids

32 Identification of yeast
Morphology Mode of sporulation Sexaul (ascospores and basidiospores) Asexual (blastocoidia, pseudo-hyphae, true-hyphae, arthorspores, …etc) Physiological tests

33 pityriasis versicolor caused by Malassezia species

34 pityriasis versicolor
Direct examination pityriasis versicolor Filaments are not seen at unaffected skin sites or in culture

35 Culture of Candida yeast

36 Candida albicans “methylene blue stain”

37 Candida species C. albicans (50-60 % of all yeast infections)
C. glabrata C. tropicalis C. parapsilosis

38 Examples of moulds of medical importance
Dermatophytes Aspergillus species Zygomycetes

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40 Identification of moulds
Hyphae Septation Zygomycetes Ascomycetes or basidiomycetes Rate f growth Color of hypahe Mode of sporulation Sexaul (ascospores, basidiospores, or zygospores) Asexual (conidia, micro or macro-conidia, sporangiospores, arthorspores, …etc)

41 Aspergillus species

42 Penicillium species

43 Scedosporium apiospermum

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45 Tinea corporis Tinea corporis caused by M. canis following contact with infectious cat

46 Hyphae in skin scraping

47 Examples of dimorphic fungi of medical importance
Blastomyces dermatitidis Histoplasma species Coccidioides immitis Paracoccidioides brasiliensis

48 Blastomycosis in the brain


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