GK-12 Saturday Workshop

December 3, 2011

Kirby-Bauer Method• The Kirby-Bauer method is the most widely used antibiotic

susceptibility test in determining what treatment of antibiotics should be used when treating an infection

• Bacteria are grown on agar plates in the presence of thin discs containing relevant antibiotics. If the bacteria are susceptible to a particular antibiotic, an area of clearing surrounds the disc where bacteria are not capable of growing (called a zone of inhibition).

• If the organism is susceptible to a specific antibiotic, there will be no growth around the disc containing the antibiotic.  Thus, a “zone of inhibition” can be observed and measured to determine the susceptibility to an antibiotic for that particular organism.  The measurement is compared to the set criteria, the organism can be classified as being Resistant (R), Intermediate (I) or Susceptible (S).

Lesson #1: Reducing Risk

Summary

• Students will investigate the effects of various antimicrobial solutions upon the growth of bacteria by measuring the zone of inhibition.

• We will collect data and analyze using Excel.

• Based on their observations, students will compare various methods for preventing the growth and spread of microorganisms.

Lesson #1: Reducing Risk

Prior Knowledge and Standards

Lesson #1: Reducing Risk

• Students will have an introduction on infectious diseases and methods of prevention.

• Students will have been introduced to bacteria and antibiotics.

• Standards addressed: 7.7 a-e, 7.1 a, 7.1 c

Lab Handout

Lesson #1: Reducing Risk

Timeline

Day 1• Introduce lab activity

• Demonstrate how to set up a petri dish and sterile technique.

• Set up bacterial plates with antibiotic discs

Day 2

• Collect Data

• Review Concepts

• Conclusion Questions

Lesson #1: Reducing Risk