A B C D E F G H I J L K Infectious Diseases Unit 2 Lesson 7 plan

Do now If you go to the doctor with a bacterial infection, how will they know what you have? Why would you want to know which bacteria is causing the infection?

Activity: What’s in your nose!

Antibiotic susceptibility The empty areas surrounding the discs show where antibiotics diffused into the agar and killed the bacteria or ? Complete the worksheet in groups and prepare to share your data with the class.

Identifying antibiotic susceptibility of Staph Aureus 1.Label the worksheet with the number of your MSA plate. 2.Label each of the circles with the initials on the antibiotic disk. 3.Draw a picture of the zone of inhibition (ZOI) around each circle 4.Measure the diameter of the ZOI in millimeters and then record it on in the table. Antimicrobial agentDose Diameter of zone of inhibition (ZOI)

Antimicrobial agent + dose Diameter of ZOI from each of the lawn plates from this MSA plate) Average zone of inhibition + standard deviation ZOIs from each lawn plate from MSA plate___:

Compare different MSA plates: Anti-microbial: MSA plate Susceptible >17mm Unsusceptible <13mm

Wrap up We used differential growth susceptibility to determine whether Staph Aureus grows in your nose. Why might it be important to know what is growing in your nose? A B C D E F G H I J L K

Wrap up If you can’t identify a bacterium how would you choose an antibiotic? A B C D E F G H I J L K

Wrap up If you can’t identify a bacterium how would you choose an antibiotic? – All of them! (multi-drug therapy) A B C D E F G H I J L K

Homework Read about Staphylococcus Aureus Answer the question: Is Staphylococcus Aureus in the nasal cavity an infectious agent?