bact morphology

• What is the general size range of bacteria?

  0.4 to 2 µm
• What is the largest bacterium known?

  Thiomargarita namibiensis
• Where is Thiomargarita namibiensis found?

  In ocean sediment
• What is the diameter range of Thiomargarita namibiensis?

  0.1 to 0.3 mm
• What is a direct smear?

  Preparation of primary clinical sample
• What does a direct smear identify in a specimen?

  Number of cells present
• What is an indirect smear?

  Sample processed in culture
• What does an indirect smear include?

  Preparation from solid or semisolid media
• What is staining in microbiology?

  Applying dyes to specimens
• What is a positive stain?

  Dye sticks to the specimen
• What is a negative stain?

  Dye settles around the specimen
• What are simple stains?

  Require only a single dye
• What are differential stains?

  Use two different colored dyes
• What are special stains used for?

  Developed for a specific purpose
• What is the most commonly used stain in clinical microbiology?

  Gram Stain
• What are the two main groups identified by Gram Stain?

  Gram-positive and Gram-negative
• What is the purpose of Acid Fast Stains?

  Stain bacteria with high lipid content
• What does Acridine Orange stain?

  Binds to nucleic acid of the cell
• What does Calcofluor White stain?

  Binds to chitin in fungal cell walls
• What is Methylene Blue used for?

  Stain C. diphtheriae for granules
• What is Lactophenol Cotton Blue used for?

  Stain cell walls of medically important fungi
• What do India Ink and Nigrosin visualize?

  Capsules surrounding certain yeasts
• What is the Schaefer-Fulton spore stain used for?

  Stain bacterial spores
• What is the importance of colony morphology as a diagnostic tool?

  • Provides presumptive identification to physicians
  • Enhances quality of patient care
  • Plays a role in quality control
• What does primary plating refer to?

  Inoculation of clinical specimen onto media
• What happens after 18-24 hours of incubation?

  Growth of bacteria in petri dish
• What is plate reading?

  Interpretation of primary cultures
• Can all organisms that grow on Chocolate Agar grow on Sheep Blood Agar?

  No, not all can grow on Sheep Blood Agar
• What is a-hemolysis?

  Partial lysing of RBCs in SBA
• What is B-hemolysis?

  Complete clearing of erythrocytes in SBA
• What does no hemolysis indicate?

  No lyses of RBC; gamma hemolysis
• What are the size categories for colony morphology?

  Large, Medium, Small, Pinpoint
• What are the forms or margins of colonies?

  Smooth, Filamentous, Rough, Irregular
• How is elevation determined in colony morphology?

  By tilting the culture plate
• What are the elevation types in colony morphology?

  Raised, Convex, Flat, Umbilicate, Umbonate
• What does density refer to in colony morphology?

  Transparency of the colony
• What are the color categories for colonies?

  White, Gray, Yellow, Buff
• What are the consistency types in colony morphology?

  Brittle, Creamy, Dry, Waxy
• What is the significance of odor in colony morphology?

  Indicates specific bacterial species
• What is the pigment produced by P. aeruginosa?

  Green with metallic sheen