Microbiology: microscopic examination/interpretation

What are the 3 types of living-state microscopic exams?

Wet mount, hanging-drop, KOH (potassium hydroxide)

What is a wet mount exam?

One drop of fluid on a slide with a coverslip; not liquid, can add a small amount of sterile saline

What is a hanging-drop exam?

Uses a special depression slide and a coverslip with petroleum jelly

What is a KOH/potassium hydroxide exam?

KOH dissolves keratin in cells, to view fungal elements

What are hanging-drop exams used to analyze?

Microbial motility

What is an example of a specimen prepared as a wet mount?

Vaginal wet prep

How is a fixed-state slide prepared?

1. create a monolayer of specimen

2. air dry

3. fix to slide using heat or methanol

4. label appropriately

What are the 3 types of stains?

Simple, probe-mediated, differential

What is a kind of simple stain?

Methylene blue

What is a methylene blue stain used to detect?

Fecal leukocytes

What is a kind of probe-mediated stain?

Anti-nuclear antibody (ANA)

What are the 4 kinds of differential stains?

Gram stain, fluorochrome, acid-fast, acridine orange

What is an acridine orange stain used to analyze?

Stains the nucleic acid material of organisms

What is a gram stain used to visualize?

bacteria, RBCs, WBCs, epithelial cells

What is an advantage of using a fluorochrome stain over an acid-fast stain?

Fluorochrome gives enhanced detection and higher sensitivity

What is the purpose of making a “monolayer” when preparing a fixed-state slide?

Allows for accurate viewing of separated cells and organisms