MICRO FINALS LAB

• Staining Methods


  • Wet Mount
  • Hanging Drop Prep
  • Fixed Stain Smear
• Methods of Fixation


  • Heat
  • Methanol
• Purpose of Fixation


  • Kills Organism
  • Preserves their morphology
  • Anchor smear to the slide
• Gram Stain


  • Developed by Hans Christian Gram (1884)
  • Studying bacteria on respiratory
  • Gram positive/ Gram negative
  • Single most important technique
  • Not fool proof procedure
  • Prone to operator error
  • Requires large number of Bacteria
• Staining Methods


  • Direct Staining
  • Indirect/Negative/Relief Staining
• Direct Staining


  • Simple Staining
  • Differential Staining
• Differential Staining


  • Gram Staining
  • Acid Fast Staining
• Acid Fast Staining Methods


  • Ziehl Neelsen
  • Kinyoun's Cold Staining
  • Truant's Auramine Rhodamine Method
  • Pappenheim's Method
  • Baumgarten's Method
• Selective Staining


  • Spore stain
  • Capsule Stain
• Reagents Used


  • Initial Staining
  • Mordant
  • Decolorizer
  • Secondary Stain
• Dye


  • Organic compound responsible for coloring/staining
  • Chromopore Group - give specific color to compound
  • Auxochrome - transferring the color of the dye to a substance or material to which the dye will act upon
• Culture Media


  Artificial media or synthetic media, because they do not occur naturally; rather, they are prepared in the laboratory
• Purpose of Culture Media


  • Isolate bacteria in pure cultures
  • To demonstrate their properties
  • To obtain sufficient growth of bacteria for preparation of antigen/test
  • To determine sensitivity of microorganism to antibioics
• Culture


  Growth or crop of microorganisms obtained in a culture medium after its incubation period
• Culture Medium


  Any material where microorganisms may thrive for their nourishment and reproduction
• Incubation Period


  Time needed to let previously inoculated culture media to show a distinct colony
• Colony


  Group of microorganisms growing together characteristically in a culture medium
• Inoculum


  The fished out colony hanging on the wire loop, cotton swabs
• Chemically Defined Medium


  • All ingredients are known
• Enriched Medium


  • Broth/solid promote growth of fastidious organism (chocolate agar)
• Selective Medium


  • Added inhibitors to discouraged growth of certain organism and allow the other
• Types of Culture


  • Contaminated
  • Mixed
  • Pure
• Types of Artificial Media


  • Brain Heart Infusion
  • Sheep Blood Agar
  • Chocolate Agar
  • Macconkey Agar
• Classification Based on Nutritional Components

  • Simple Media
  • Complex Media
  • Synthetic Media
• Physical State of Culture Media

  • Solid/Semi Solid
  • Liquid
• Types of Culture Media Used


  • Simple Media
  • Enriched Media
  • Selective Media
  • Differential Media
  • Transport Media
• Nutrient Broth

  • Meat Infusion Broth
  • Meat Extract Broth
  • Digest Broth
• Common Media Used

  • Blood Agar
  • Chocolate Agar Plate
  • Selenite Broth
• Types of Incubator

  • Carbon Dioxide Incubator
  • Non CO2
  • Anaerobic Incubator
• Spectrophotometer


  A beam of light is passed through the liquid. When no bacteria are present in the liquid, the liquid is clear, and a large amount of light passes through. As bacteria increase in number, the liquid become turbid and less light passes through. Measures light absorbed by sample.
• Viable plate count


  Used to determine the number of viable bacteria in a liquid sample, such as milk, water, ground food diluted in water, or a broth culture. In the clinical microbiology laboratory, a viable cell count is an important part of urine culture. The number of viable bacteria per milliliter of urine specimen is used as an indicator of urinary tract infection (UTI).