Microscopy ID

Question 1

bright field

Answer 1

-bacteria, fungi, parasites

Question 2

fluorescence

Answer 2

bacteria, fungi, parasites, and viruses

Question 3

dark field

Answer 3

spirochetes

Question 4

electron microscopy

Answer 4

viruses and microsporidia

Question 5

gram stain general

Answer 5

• gram + - retain dye complex
• gram - = loses purple color after decolorization
• observe presence of inflammatory cells

Question 6

gram stain procedure

Answer 6

1) cells on slide
2) primary stain crystal violet
3) mordant grams iodine (stains everything purple)
4) decolorizer alcohol and/or acetone (here is where gram - loses color)
5) counterstain safranin colors only gram- pink

Question 7

utility of gram stain

Answer 7

• diagnosis
• determine quality of specimen
• suggest an unusual org or provide early presumptive bacterial id
• verify the clinical relevance of the culture

Question 8

acid fast stains

Answer 8

• designed to stain bacteria with cell walls containing long chain fatty acids
• use heat or detergent to drive stain into the cell, once in the cell if it resists decolorization = acid fast bacilli
• stains mycobacteria, nocardia, cryptosporidia, and cyclospora
• methods = kinyoun (cold) or ziehl-neelsen

Question 9

acid fast procedure

Answer 9

1) cells on slide
2) primary stain (carbalfuchsin red)
3) decolorizer (HCl, alcohol)
4) counterstain (methylene blue)

Question 10

special fungal stains

Answer 10

• lactophenol cotton blue
• gomori methenamine silver (GMS) - yeast cells and hyphae and pneumocystis carinii
• Periodic acid-Schiff (PAS) - yeast cells and hyphae
• mucicarmine (mucin) - cryptococcus capsule

Question 11

warthin-starry or steiner stain

Answer 11

• silver impregnated stain for formalin fixed tissue

- demonstrate spirochetes, cat scratch disease (B henselae)

Question 12

parasite stains

Answer 12

• wright’s giemsa
• wet mounts
• trichrome
• modified acid fast

Question 13

wright’s giemsa

Answer 13

• used to examine peripheral blood smear

- detect hisoplasma, leishmania, trypanosoma, malaria

Question 14

flourescence stain

Answer 14

• fluorophores or fluorochromes absorb energy from nonvisible UV and short visible wavelengths which become exited and emit the energy in the form of longer visible wavelengths
• color of fluorescence depends on dye and filters on the special microscope

Question 15

fluorescent microscopy

Answer 15

• auramine-rhodamine - mycobacteria
• calcofluor white stain - fungi
• fluorescein conjugated antibodies - viruses, bordetalla, legionella, pneumocystis