WEEK 2 pt 1

What is one purpose of microscopy in diagnosing infection (presumptive, not final)?

Microscopy

What role does microscopy play in analyzing cultured organisms?

Microscopy

What tool is used to visualize bacteria, yeast, and parasites not visible to the naked eye?

Microscopy

What is microscopy used for in evaluating specimen adequacy (e.g., Bartlett's classification)?

Microscopy

Which microscopy uses visible light and shows a dark specimen on a bright background?

Bright-field Microscopy

What determines the magnification in microscopy?

Magnification

What is the formula used to calculate total magnification?

Total Magnification

What is an example of low power magnification?

Low Power

What term refers to how clearly a focused object is maintained?

Resolution

What refers to the closest distance between two magnified objects that can still be distinguished?

Resolving Power

What is used in 1000x magnification to improve resolution between slide and lens?

Immersion Oil

What feature helps an object stand out against the background in microscopy?

Contrast

What is commonly used to achieve contrast in microscopic imaging?

Staining Techniques

Which microscopy allows direct observation of unstained specimens such as wet mounts?

Phase-Contrast Microscopy

Which microscopy technique is used to observe viable organisms and their internal structures?

Phase-Contrast Microscopy

What special condenser component is used in phase-contrast microscopy?

Annular (ring-shaped) diaphragm

How is the image formed in phase-contrast microscopy?

By combining direct and reflected/diffracted light

What are fluorescent dyes that absorb UV and emit visible light called?

Fluorochromes / Fluorophores

What is the process where dyes directly interact with bacterial components?

Fluorochroming

What technique uses antibodies conjugated to fluorescent dye (e.g., FITC)?

Immunofluorescence

How do fluorescing objects appear in fluorescent microscopy?

Bright against a dark background

What filter protects the observer's eyes and selects transmitted light?

Excitation / Barrier Filter

What is often used to create permanent records in fluorescent microscopy?

Digital Photography

What microscopy is a light from below the specimen is blocked (condenser), so that it reaches the object at a sharp angle?

Darkfield Microscopy

What microscopy is where the spcimen appears luminous against a dark background this is limited to a specialized research facility and used primarily to view spirochetes, this dimnesions exclusive?

Darkfield Microscopy

What is a small sample of the specimen or culture to be studied?

smear

What type of smear is made directly from the patient sample?

Direct Smear

Why might organisms be seen on a direct smear even if no culture growth occurs?

Slow-growing organism, antibiotic treatment, or improper processing

What type of smear is made from cultures grown in artificial media?

Indirect Smear

What is the preferred age of cultures for indirect smear preparation?

24-hour cultures

What factors influence the type of smear preparation used?

Specimen type and desired staining method

What is the requirement for smear material application?

Sufficient material in a thin layer

How many swabs are needed for both smear and culture testing?

Two swabs

What should be done if only one swab is available?

Prepare the smear immediately

What smear method is used for thick, granular, or mucoid materials?

Squash Preparation

What are the proportions used for squash smear prep?

2 width : 3 height

What method is used to smear acid-fast sputum?

Coil

What is a precaution when preparing smears from thin fluids like CSF?

Do not spread too much

What can be drawn on a slide to guide placement of thin fluid samples?

Guideline

What technique is used to concentrate and spread cells in fluids?

Cytocentrifuge Preparation

From what sources can smears be made aside from patient samples?

Culture Media (solid or liquid)

What organic or aqueous dye preparations that color tissues/microorganisms?

Stains

Which type of dye is more commonly used in microbiology?

Basic Dyes

Why do basic dyes easily bind to bacterial cells?

Bacteria are slightly negatively charged at pH 7

What are some examples of basic dyes?

Crystal violet, Methylene blue, Malachite green, Safranin

What type of dye is not attracted to bacteria and colors the background instead?

Acidic Dyes

What staining technique uses acidic dyes to color the background, not the organism?

Negative Staining

What is the process of coloring a microorganism in a thin film on a slide called?

Staining

What type of stain uses only one dye and gives all structures the same color?

Simple Stain

What stain is to observe size, shape, morphology, and presence of microorganisms?

Simple stain

What staining method uses more than one dye to show different structures?

Differential Stain

What staining method is used to color specific parts of a microorganism?

Special Stain

What are common dyes used in simple staining?

Methylene blue, Carbolfuchsin, Crystal violet, Safranin

Which bacterium shows metachromatic granules when stained with methylene blue?

Corynebacterium diphtheriae

What are metachromatic granules in Corynebacterium also called?

Babes-Ernst granules

Who developed the Gram staining technique?

Hans Christian Gram

What is the most commonly used staining method in bacteriology?

Gram Stain

What stain is part of the GSC test (Gram stain and culture sensitivity)?

Gram Stain

What does the Gram stain help rapidly identify?

Presumptive pathogens and specimen quality

What is the basis for differential staining in the Gram stain?

Cell wall characteristics

What retain the crystal violet-iodine (CV-I) complex?

Thick cell walls (peptidoglycan)

What component of a stain helps bind the stain to a structure?

Mordant

Which stage of Gram staining is considered the most critical?

Decolorizer

What type of stain is used for organisms with mycolic acid in their cell walls?

Acid-fast Stain

Which bacterial genus resists decolorization due to mycolic acids?

Mycobacteria

Which organisms lack a cell wall but contain sterols and are not acid-fast?

Mycoplasma, Ureaplasma

Why should tap water not be used in acid-fast staining?

Due to tap water bacillus like Mycobacterium gordonae

What acid-fast method uses heat to penetrate the primary stain?

Ziehl-Neelsen Method

What cold acid-fast method uses higher phenol (tergitol) concentration instead of heat?

Kinyoun Method

What modified method uses 1% sulfuric acid (H₂SO₄) as a decolorizer?

Modified Kinyoun Method

Which organisms are stained using the modified Kinyoun method?

Intestinal coccidian oocysts (Isospora, Cyclospora)

What are examples of partially acid-fast organisms?

Nocardia spp., Cryptosporidium

Which stain colors the background using acidic dye while cells remain colorless?

Negative Stain

Which structures are demonstrated using the negative stain?

Capsules, bacterial gas vacuoles, viral morphology

What are some examples of negative stain techniques?

Anthony’s, Hiss’s, Gin’s, India Ink, Welch

What dye is used in the India Ink method?

Nigrosin dye

Which negative stain method uses hot crystal violet and copper sulfate rinse?

Welch Method

What staining method uses tannic acid salts to make flagella visible?

Flagella Stain

Which stains are used in Gray’s method for flagella?

Carbol fuchsin and Tannic acid

Which stains are used in Leifson’s flagella method?

Carbol fuchsin, Tannic acid, and Methylene blue

Which nucleic acid stain is specific for DNA?

Fuelgen

Which fluorochrome binds all nucleic acids and is used to stain Mycoplasma?

Acridine orange

What staining method is used for intracellular refractile bodies like spores?

Endospore Stain

Which endospore method uses Carbol fuchsin and Nigrosin dye?

Dorner Method

Which endospore stain uses Malachite green and Safranin?

Schaeffer-Fulton Method

Which fluorescent dye binds to mycolic acid in mycobacteria?

Auramine-rhodamine

Which fluorescent dye binds to chitin in fungal cell walls?

Calcofluor white

Which organisms can be visualized using Calcofluor white?

Fungi and Microsporidia

Which fungal stain contains lactic acid, phenol, and cotton blue?

Lactophenol cotton blue

What component of LPCB acts as the preservative?

Lactic acid

What component of LPCB inhibits other fungal growth?

Phenol

What component of LPCB stains chitin in the fungal cell wall?

Cotton blue

Which fungal stain is used for elements found in tissue sections?

Methenamine silver

Which stain is preferred for direct clinical samples in fungal detection?

Periodic acid-Schiff (PAS)

What does PAS stain target in fungal structures?

Molecules with high carbohydrate content

What is the purpose of grading or classifying clinical specimens?

To separate representative from contaminated samples before culture

Which scoring method evaluates sputum based on squamous cells and PMNs?

Bartlett’s Q scoring

Which method focuses on the ratio of squamous cells to PMNs?

Murray-Washington method

Which method emphasizes the ratio of SECs to PMN leukocytes?

Heineman’s method

Which system is used to grade Gram-stained vaginal smears?

Nugent scoring system