Introduction Medical Mycology

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Introduction Medical Mycology

• Prof. Dr. Asem Shehabi
• Faculty of Medicine
• University of Jordan

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General Fungi-1

• Fungi are eukaryotic microorganisms.. Larger
  than bacteria occur as Yeasts (unicellular cells
  0.5-4 um) or Molds/ filamentous Fungi..
  composed of various cellular structures spores,
  filaments/Hyphae.. cells up 20um)..
• Nest branching filament/ Multicellular fungi
• Masses of Hyphae are called mycelium.
• In molds, the mycelia often spread to fill the
  available space, limited by available nutrients.

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Hypha Cell-Yeast Cell
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General Fungi-2

• Essentially Aerobic .. Mostly found in Nature
  living in association with plants ..often as
  harmful organisms..free saprophytes on dead
  organic substances.
• Fungi have chemoheterotrophic metabolisms,
  obtaining nutrients through chemical absorption..
  Certain Fungi .. Producer Antibiotics..
  Decompose organic materials.. plants.
• Molds Reproduction by various spores, hyphae..
  apical extension of cells..
• Yeast Mostly reproduce asexually by budding,
  although a few reproduce by binary fission.
• Baker's yeast/ Saccharomyces cerevisiae.. Sugar-
  Fermentation.. Important in Production Bread..
  Vitamins Medical drugs like Insulin.

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1-Aminata Toxic Mushroom 2-Non-Toxic Mushroom in
Nature
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Fungi cell Structures

• About 100 Fungi types are opportunistic
  pathogens.. Yeast part normal flora.. Oral
  cavity-intestine-Vagina.. Few types true
  pathogens
• They are not susceptible to antibacterial drugs ,
  phages
• Fungi Cell wall Mostly Polysaccharides (chitin,
  glucan, mannan), lipid-phosphate-protein,
  protease, melanin . Their Plasma membranes
  containing Ergosterol, Cytoplasm contains
  microtubules composed of tubulin/Specific
  Protein..Mitochondria, Lipids phosphate
  granules
• Pathogenic Yeasts produce often elongated Oval
  cell Pseudohyphe on body mucosal cells
  ..Pathogenic Mold single and multiply
  filaments.. cell fragments in infected tissue.
• Antifungal drugs Nystatin, Fluconazol,
  Amphotericin B, Casbofungin.. All react with
  ergosterol forming compmlex molecules.. damage
  cell membrane.

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Budding Yeast/Germ Tubes
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Capsulated Yeast / Cryptococcus neoformans
(India ink test)
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Filaments Fungi/ Molds

• Molds form multicellular filaments/ hyphae ..
  non-septate/ septate hyphae.. spores of different
  sizes.. color.. arrangement .. A mass of hyphae
  and spores represent Aerial Vegetative Mycelium
• Dimorphic Pathogenic fungi grow as Yeasts or
  Yeast-like structure in vivo at 37C, but as
  Molds at 25C
• Lab Identification Direct smear .. Culture on
  Sabourauds dextrose agar/ blood agar.. Slow or
  rapid growth (2-30 days).. Morphology
  reproduction of spores/yeast cells/ Filments
  (Hyphae).. Colors of Micro/Macro Conidia..
  Arrangement of spores on septet or non-septet
  hyphae.

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Human Mycosis-1

• Dermatophytosis /Superficial Mycoses/ Cutaneous
  Mycoses/ Ringworm / Tinea ..
• Involve superficial keratinize.. Dead tissues..
  skin, hair, Nails.. Caused by Dermatophytes
  Trichophyton - Microsporium -, Epidermophyton
  species
• Worldwide distribution.. Spores, Hyphae
  fragments.. Common in nature, skin human,
  animals.
• Tinea versicolor / Pityriasis versicolor.. Yeast
• Clinical Features Erythematic Skin
  lesions..Rare inflammation.. Allergic reaction..
  Common under stress conditions.. Fever, Unknown
  Factors.

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Human Mycosis-2

• Skin spots commonly affect the back, underarm,
  upper arm, chest, lower legs, and neck.
  Occasionally it can also be present on the face.
• The yeasts can often be seen under the microscope
  within the lesions with typically round yeasts
  filaments. Light to Dark patches on skin..
  Difficult to culture.
• Hair Tinea capitis, Hairshaft /hair follicles.
  Scalp, Endo-Exothrix, Common in Children.. Rare
  Adults.. Infection Outbreaks .
• Nail Tinea unguium Tinea pedis.. Feet fingers,
  Feet interspace, moist skin lesions, Common in
  Adults, develop Chronic
• Causative agents Dermatophytes.. Trichophyton -
  Microsporium -, Epidermophyton species.

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Tinea corporis-
Pityriasis versicolor
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Tinea unguium Tinea
Tineacapitis
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Microconidia-Macroconidia
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Penicillinums-Trichophyton spp.
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Yeast /Candida species

• Candidiasis/ Candidiosis C. albicans (50-70)..
  Less C. glabrata, C. tropicalis., C. Krusei..
  Others spp.
• Part normal body Flora.. Mouth, Vagina, Skin,
  Intestine, Urinary tract.
• Opportunistic Pathogens.. mostly endogenous
  infection, arising from overgrowth of the fungus
  .. intensive use of antimicrobial drugs..
  Inhibiting normal flora.. Underlining diseases,
  compromised host, Radiation, Toxic drugs
• Exogenous infection .. catheters or prosthetic
  devices.. Respiratory tubes.. person-to-person
  transmission,
• Common Nosocomial Infection.
• Clinical Features Oral mucosa.. Thrush ..
  Throat- Pharynx, Lung , Candidiasis ,vaginal
  Candidiasis.. discharge Irritation, Candidemia,
  meningitis.

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Candida Pseudohyphae ( Chlamydo-Blastospores)
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Candida Trush
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Other Yeast Infection

• Encapsulated C. neoformans.. Large Capsule..cause
  a chronic- subacute- acute pulmonary.. May spread
  to blood, CNS.. causes ..systemic or meningitic
  disease.. Often isolated from pigeon, Birds
  excreta.
• C. neoformans has a world-wide distribution.. now
  one of the most significant opportunistic
  pathogens in humans.. immunodifficient ..AIDS
  patients..

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Mold infection Aspergillosis

• Aspergillus species are common in nature ..
  Spores spread with dust particles..Inhalation. .
  Few develop Allergy or clinical disease
• A. fumigatus, A. flavus, A. niger.
• Human Aspergillosis Mycotoxicosis due to
  ingestion of contaminated foods with fungal toxin
  ..Peanuts, Rice,
• A. flavus .. Produce Aflatoxins.. Liver
  cirrhosis..Death
• 2) Allergic Bronchopulmonary Aspergillosis
  Presence of conidia or transient growth of the
  organism in body Respiratory tract.. Sinuses..
  often associated with Allergic reaction
  ..Eosinophilia.. Asthma..
• 3) Pulmonary lesions in preformed cavities ..
  debilitated tissues.. Common in Tuberculosis
  Lung carcinoma, Localized Lesions, ..Eye ,
  Sinuses, External Otitis infection Surgery
  Antifungal Treatment

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1-Aspergillus niger growth2- Wet preparation,
Aspergillus