Detection Methods Flashcards
Performed using touch preparations
Tissues (smear)
Sample that Must be rolled back and forth across a dry, clean slide
Swabs
Aspirates or body fluid Prep if high number of organisms are expected and if the specimen is thick
Single-drop smear
Aspirates or body fluid Prep if a small number of organisms is expected
Centrifuged smear
Aspirates or body fluid Prep used for low-volume specimens
A drop is placed on slide and allowed to dry. Another drop is placed on top of dried smear
Layered Smear
Aspirates or body fluid Prep where an aliquot of the specimen is spun directly into a slide
Cytocentrifuged smear
May be added to CSF to help cellular materials adhere to the slide
Albumin
May be added to extremely mucoid specimens
Mucolytic
What is gram stain?
A staining method that places bacteria into one or two groups (g+,g-) and determines g/s characteristic
Gram stain reagent contact times: Crystal violet Gram’s iodine Acetone-alcohol Safranin Red
1 min
1 min
3-5 seconds, rinse with water
1 min
G/S Primary stain
Crystal violet
G/S mordant
Gram’s iodine
G/S decolorizer
Acetone-alcohol
G/S counterstain
Safranin red
G+ cell wall color after gram stain
Purple
PoPu
G- cell wall after gram stain
Pink
NePu
Color of G- cell wall when not decolorized
Purple
What does gram stain have that acid-fast stain does not have?
Mordant
Acid-fast stain is primarily used to detect…
Mycobacterium species (TB)
Fuchsin Stain that is also known as the cold method; uses a higher concentration of detergent to facilitate staining
Kinyoun method
Fuchsin stain that is also known as the hot method; uses heat to facilitate staining
Ziehl-Neelsen Method
Acid-Fast Stain Contact Time:
Carbolfuchsin
Acid-alcohol
Methylene blue
5 min., flame/steam, rinse, a few min., rinse
Decolorize until no more stain comes off/ rinse water
1 min., rinse, dry, examine
What is the purpose of carbolfuchsin in acid fast stain?
Primary stain
What is the acid-fast stain decolorizer
Acid-alcohol
What is the purpose of methylene blue in acid fast staining?
Counterstain
Acid-fast cell wall will appear ____ after staining
Red
Non acid-fast cell wall will appear ___ after staining
Blue
Fluorochrome stain that stain acid-fast organism fluorescence yellow or orange under a fluorescent microscope
Auramine-rhodamine
Used to observe metachromatic granules in corynebacterium diphtheriae
Methylene blue
Fluorochrome dye that stains both g+ g- organisms both living and dead
Acridine orange
To determine the biological activity of microorganisms including motility or reactions to certain chemicals or serologic reactivity in specific antisera
Saline mount
Uses slide but with deeper field of focus (because of depression slide) and without the distorting effects from weight of coverslip
Generally used to observe motility
Hanging-drop method
Used to visualize organisms that are invisible by brightfield microscopy and stain only with great difficulty
Useful in demonstrating spirochetes
Darkfield examination
Assess quality of sputum samples
Book page 18
Culture medium that contains no agar or any hardening or solidifying agents
Liquid
Agar percentage of semi-solid culture media
0.5-1.0%
Culture medium that contains 2-3% agar
Solid
Polysaccharide extract of seaweed/algae
Agar
Culture medium that exact composition is known. Commercially prepared
Synthetic
Culture medium thats exact composition is not known. Meat extract broth
Non-synthetic
Culture medium made up of living cells
Cell culture
Uses petri dishes
Plated media
Use sterile test tubes
Tubed media
Culture media that supports most non-fastidious bacteria
Non-selective media
Culture media that supports the growth of one type of bacteria and not the other. Has inhibitory substances
Selective media
Allows grouping of bacteria on the basis of different characteristics displayed on the medium. May be Selective or non-selective
Differential medium
Designed to isolate fastidious bacteria. Has growth enhancers
Enriched media
Designed to encourage growth of small numbers of a particular organism while suppressing the other flora present in the specimen
Enrichment broth (selective enrichment)
Prevents replication while keeping bacterial cells viable
Transport media
