Attack of the Superbugs Lab Introduction Mrs. Stewart Medical Interventions

Superbugs What is a “superbug”? Bacteria that have become stronger and less responsive to antibiotic treatment

How can bacteria share resistance? Genetic Transfer Method Description Conjugation The one-way transfer of DNA (plasmid) between bacteria in close cellular contact Transformation The genetic modification of a bacterium by incorporation of free DNA from the surrounding environment (usually caused by another ruptured bacterial cell) Transduction The transfer of genetic material from one bacterium to another by a genetic vector (bacteriophage virus)

This lab uses 2 types of Bacteria: E. coli I contains a gene found on the chromosomal DNA coding for streptomycin resistance E. coli II contains a gene found on the plasmid DNA coding for ampicillin resistance.

Predict What will happen when the E. coli I strain is mixed with the E. coli II strain?

Lab Materials: 4 growth plates LB Agar LB + Str LB + Amp LB /Str /Amp *LB Agar = growth medium for bacterial cells

Lab Day 1: Obtain 2 of each type of growth plate Streak E. coli I on 4 plates Streak E. coli II on 4 plates Incubate overnight *These will be the confirmation plates

Evaluate What are we confirming?

Lab Day 2: Observe confirmation plate results Prepare “mix” plate You will literally be mixing the two types of bacteria together onto one plate Incubate overnight

Evaluate Why are we mixing them together?

Lab Day 3: Use new “mixed” bacterial cultures and spread onto the 3 types of antibiotic plates

Predict What would you expect to see on these growth plates? Why?

FRIDAY – Lab Day 4 You must come in at some point during the day Friday to observe and record your results Remember: Pictures of lab results will be required in your lab reports *Growth plates will be discarded at 3:10 pm on Friday. Any results not recorded will be lost.

Student Lab Schedule Day: Time Needed: Activity: How to Store: Additional Info: Lab Day 1 ~ 30 minutes Students prepare confirmation plates. Invert the plates, label, and incubate at 37˚C for 24 hours. (1) Students complete steps 1 – 33 on P.1.2.2. (2) Students work through the mechanisms of antibiotic resistance animations. Lab Day 2 Students observe confirmation plates and prepare “Mix Plate.” (1) Students complete steps 34 – 47 on P.1.2.2. (2) Students begin construction of 3-D model. Lab Day 3 Students streak cultures from “Mix Plate” onto antibiotic plates. (1) Students complete steps 48 – 60 on P.1.2.2. (2) Students continue construction of 3-D model. Lab Day 4 ~ 10 minutes Students make observations of plates to test for antibiotic resistance. Clean-up all materials. (1) Students complete steps 61 – 65 on P.1.2.2. (2) Students complete work on 3-D models and present models to class. (3) Students answer all remaining Conclusion questions.