Exam 1 (Ch 8 - Presumptive ID stuff) Flashcards
Preliminary general identification of an organism, based on early results
Presumptive identification
Why is the presumptive identification needed?
Because growth and ID can take days or longer—patients can’t always wait
5 basic steps to final identification
- Receive and set up specimen
- Immediate smear, prelim ID
- Next day: read plates, re-incubate if needed
- Prelim ID, re-streak, or additional testing
- Final ID (from instrument or manual testing)
5 types of microscopy
- Brightfield
- Fluorescent
- Darkfield
- Phase Contrast
- Electron
Random angular arrangements of cells (usually used when describing bacterial cells on a gram stain)
Pleomorphic
Refers to a fence made of wooden stakes
- In microbiology, refers to cells arranged in an irregular fence-like pattern (also used with terms such as “log jam”, “picket fence”, “coryneforms”)
Palisades
Refers to the MLS quickly making a reliable, preliminary identification of suspected pathogens
Presumptive identification
Light from bulb illuminates through the slide and specimen
- use in stained and unstained preps
Brightfield microscopy
Specimen is stained with fluorochrome
- used for acid-fast bacilli, fungi, bacteria
Fluorescent microscopy
Uses reflected light to highlight edges of organism
- example: spirochetes (Syphilis)
Darkfield microscopy
Uses a filter to select 1 wavelength of light
- used for fungus, parasites, bacteria
Phase contrast microscopy
Uses electrons, X100,000
- used in research of virology
Electron microscopy
Finger-like projections
Filamentous
The edge of a colony
Margin
A raised center
Umbonate
