Transcript Introduction Medical Mycology

Introduction Medical
Mycology
Prof. Dr. Asem Shehabi
Faculty of Medicine
University of Jordan
General Fungi-1
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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.
Hypha Cell-Yeast Cell
General Fungi-2
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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.. SugarFermentation.. Important in Production Bread.. Vitamins
Medical drugs like Insulin.
1-Aminata Toxic Mushroom
2-Non-Toxic Mushroom in Nature
Fungi cell Structures
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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.
Budding Yeast/Germ Tubes
Capsulated Yeast / Cryptococcus
neoformans (India ink test)
Filaments Fungi/ Molds
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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 Yeastlike structure in vivo at 37°C, but as Molds at 25°C
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.
Human Mycosis-1
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Dermatophytosis /Superficial Mycoses/ Cutaneous Mycoses/
Ringworm / Tinea ..
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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
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Clinical Features: Erythematic Skin lesions..Rare
inflammation.. Allergic reaction.. Common under stress
conditions.. Fever, Unknown Factors.
Human Mycosis-2
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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.
Tinea corporisPityriasis versicolor
Tinea unguium –
Tinea Tineacapitis
Microconidia-Macroconidia
Penicillinums-Trichophyton
spp.
Yeast /Candida species
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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.
Candida Pseudohyphae
( Chlamydo-Blastospores)
Candida Trush
Other Yeast Infection
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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..
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 growth
2- Wet preparation, Aspergillus