Fish Heath Management Lab 8: Bacteriology Part 2

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Fish Heath Management Lab 8 BacteriologyPart 2

• March 30th, 2009

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Lab Objectives

• Measure zones of inhibition for antibiotic
  sensitivity tests
• Observe the streaking for bacterial isolation
• Identify bacteria isolated from Unknowns 1 and 2

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Interpreting Antibiotic Sensitivity Test

• Measure diameter of zone of inhibition (mm)
• The larger the zone, the more effective an
  antibiotic will be.

4
Bacterial Isolation

• Observe the two platesdid you get individual
  colony isolation??
• What are the characteristics of the colonies??

5
Bacterial Unknowns

• Perform unknown bacterial examinations
• Gram staining
• Chemical testing
• KOH test
• Cytochrome Oxidase test
• Motility testing

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Bacterial Unknowns
-
Heat Fixed
Crystal Violet
Gram Staining
Grams Iodine
Ethyl Alcohol
Safranin
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KOH (Potassium Hydroxide) Test

• Alternative to Gram stain
• Stringy and viscous Gram negative
• No viscous or stringy Gram positive
• KOH is caustic wear gloves and immediately flush
  skin or eyes with water if they come into contact
  with KOH solution

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Cytochrome Oxidase Test

• Identifies organisms that produce cytochrome
  oxidase
• Solution remains colorless negative (doesnt
  produce cytochrome oxidase)
• Solution turns purple or blue positive (does
  produce cytochrome oxidase)
• Results appear within 15 seconds

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Todays Lab

• All used supplies should be placed in Sharps
  container or biohazard bag
• Dont put anything in trash cans
• Wipe down work area with 95 ethanol
• Clean and turn off microscopes when finished
  (dont leave them on for the next person there
  might not be one)