Fungi. Eucaryotic Rigid cell wall(chitin, glucan) Cell membrane ergosterol Unicellular, multicellular Classic fungus taxonomy:

Transcription

1 MYCOLOGY Mycology I

2 Fungi Eucaryotic Rigid cell wall(chitin, glucan) Cell membrane ergosterol Unicellular, multicellular Classic fungus taxonomy: Morphology Spore formation

3 FFungi Yeast Mold

4 Yeastlike fungi typically round or oval smooth flat colonies reproduce by budding Identification by biochemical tests

5 Molds tubular structures called hyphae grow by branching and longitudinal extension Colonies wooly and hairy

6 Dimorphic fungi grow in the host as yeastlike forms but grow at room temperature in vitro as molds. histoplasmosis blastomycosis sporotrichosis coccidioidomycosis paracoccidioidomycosis chromoblastomycosis

7 Blastospore an asexual spore formed by budding (e.g., Cryptococcus neoformans, Candida species).

8 Spores of fungi pathogenic for humans nonmotile and spread by wind, water, and contact. All fungi, including P. jirovecii, stain with calcofluor, which appears brilliant white under the fluorescent microscope. This stain has replaced the wet mount or KOH stain in many diagnostic laboratories because fungi are easier to see. Gram stain is not usually helpful because most fungi, except Candida, remain unstained. India ink smear of cerebrospinal fluid allows visualization of a polysaccharide capsule around the cell wall and is characteristic of only one genus pathogenic for humans, the genus Cryptococcus.

9 Common invasive mycosis Candida Histoplasma Aspergillus Cryptococcus

10 THE CLINICIAN MUST DISTINGUISH BETWEEN: COLONIZATION FUNGEMIA INFECTION

11 PORTAL OF ENTRY SKIN RESPIRATORY TRACT MOUTH EYE HAIR NAILS RESPIRATORY TRACT GASTROINTESTINAL TRACT SKIN URINARY TRACT UROGENITAL TRACT

12 COLONIZATION RESPIRATORY TRACT Multiplication of an organism at a given site without harm to the host MOUTH EYE SKIN UROGENITAL TRACT

13 INFECTION RESPIRATORY TRACT Invasion and multiplication of organisms in body tissue resulting in local cellular injury. MOUTH EYE SKIN UROGENITAL TRACT

14 SUPERFICIAL MYCOSES Only cosmetic importance Limited to very superficail surfaces of hair and skin

15 CUTANEOUS MYCOSES Dermatophytes fungi that can cause infections of the skin, hair, and nails due to their ability to utilize keratin. The organisms colonize the keratin tissues and inflammation is caused by host response to metabolic by-products. These infections are known as ringworm or tinea, in association with the infected body part.

16 Dermatophytes are classified as anthropophilic, zoophilic or geophilic according to their normal habitat. Anthropophilic human hosts Zoophilic primarily in animals Geophilic from the soil

17 Tinea "Tinea" refers to a skin infection with a dermatophyte (ringworm) fungus. Depending on which part of the body is affected, it is given a specific name: Tinea capitis Tinea corporis Tinea pedis Tinea cruris Tinea ungium

18 Dermatophytes Epidermophyton Microsporum Trichophyton

19 SYSTEMIC MYCOSES Dimorphic Primary systemic pathogens Normal and immunocompromised hosts From inhalation to deeper viscera Blastomyces dermatitidis Coccidioides immitis Coccidioides posadasii Histoplasma capsulatum var capsulatum Histoplasma capsulatum var duboisii Paracoccidioides brasiliensis Penicillium marneffei

20