Gram Negative
Medical Mycology: Yeast and Pneumocystis|
Reading Assignment:|Mahon, Chapter 10, pgs 215-219, Chapter 27, pgs 626-629, 634-636, Appendix B Lecture Notes: Medical Mycology|
|U of W Tutorial on Mycology (organisms listed in objectives), www.medtraining.org[->0]|
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1. Discuss the difference between yeasts and molds.
Fungi seen in the clinical laboratory can be generally separated into two groups based on the appearance of the colonies formed:
Yeasts: Moist, creamy bacteria-like, opaque, or pasty colonies on media. They reproduce by budding. (when they start budding, they cause infections)
Molds (filamentous fungi): Fluffy cottony, woolly or powdery colonies on medium. They reproduce by sporulation.
2. Describe or diagram the following types of structures:
a. Blastoconidia- Asexual yeast reproduction by blastoconidia formation. A daughter cell buds off from mother cell. A septum is created and daughter cell detaches.
b. Pseudohyphae- Elongated blastoconidia. May align end-to-end like links of sausage. Associated with yeasts. True septae are not present. (Characteristic of Candida albicans)
c. Chlamydoconidia- Thick-walled resistant asexual spores produced by “rounding up” and enlargement of terminal hyphal cells.
d. True hyphae- Fundamental microscopic units of fungus, tube-like projections with no constictions at the cell wall. The cell walls remain parallel with no indentation.
3. Describe the appropriate specimen collection procedures, staining methods, and culture techniques used for isolation of yeast.
Collection procedures
Specimen of choice include respiratory secretions, hair, skin, nails, tissue blood or bone marrow and CSF. Swabs are inadequate. CSF: Concentrate by centrifugation before inoculation. Make India ink preparation or latex agglutination for Crytococcus neoformans with part of the specimen and then inoculate the remainder onto media.
Either culture
Reading Assignment:|Mahon, Chapter 10, pgs 215-219, Chapter 27, pgs 626-629, 634-636, Appendix B Lecture Notes: Medical Mycology|
|U of W Tutorial on Mycology (organisms listed in objectives), www.medtraining.org[->0]|
_____________________________________________________________________
1. Discuss the difference between yeasts and molds.
Fungi seen in the clinical laboratory can be generally separated into two groups based on the appearance of the colonies formed:
Yeasts: Moist, creamy bacteria-like, opaque, or pasty colonies on media. They reproduce by budding. (when they start budding, they cause infections)
Molds (filamentous fungi): Fluffy cottony, woolly or powdery colonies on medium. They reproduce by sporulation.
2. Describe or diagram the following types of structures:
a. Blastoconidia- Asexual yeast reproduction by blastoconidia formation. A daughter cell buds off from mother cell. A septum is created and daughter cell detaches.
b. Pseudohyphae- Elongated blastoconidia. May align end-to-end like links of sausage. Associated with yeasts. True septae are not present. (Characteristic of Candida albicans)
c. Chlamydoconidia- Thick-walled resistant asexual spores produced by “rounding up” and enlargement of terminal hyphal cells.
d. True hyphae- Fundamental microscopic units of fungus, tube-like projections with no constictions at the cell wall. The cell walls remain parallel with no indentation.
3. Describe the appropriate specimen collection procedures, staining methods, and culture techniques used for isolation of yeast.
Collection procedures
Specimen of choice include respiratory secretions, hair, skin, nails, tissue blood or bone marrow and CSF. Swabs are inadequate. CSF: Concentrate by centrifugation before inoculation. Make India ink preparation or latex agglutination for Crytococcus neoformans with part of the specimen and then inoculate the remainder onto media.
Either culture