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 ConjugationThe one-way transfer of DNA (plasmid) between bacteria in close cellular contact TransformationThe genetic modification of a bacterium by incorporation of free DNA from the surrounding environment (usually caused by another ruptured bacterial cell) TransductionThe 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 + Amp LB + Str LB /Str /Amp *LB Agar = growth medium for bacterial cells

Lab Day 1: Confirmation Plates Obtain 1 of each type of growth plate – 4 plates total Streak E. coli I on 4 plates Streak E. coli II on 4 plates Incubate overnight

How to label the plates I II Group Name

Evaluate What are we confirming? These plates will confirm that our strains of E. coli are correctly labeled

Data Table E. coli IE. coli II LB agar LB + Str LB + Amp LB + Str + Amp + = Growth/ -- = No Growth

Prediction Predict the results from your confirmation plates that you will expect to record

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 Specifically, what will happen when we mix 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?

Lab Day 4 Observe and record your results Remember: Pictures of lab results will be required in your lab reports *Growth plates will be discarded after today. Any results not recorded will be lost.

Student Lab Schedule Day:Time Needed: Activity:How to Store: Lab Day 1 ~ 30 minutes Students prepare confirmation plates. Invert the plates, label, and incubate at 37˚C for 24 hours. Lab Day 2 ~ 30 minutes Students observe confirmation plates and prepare “Mix Plate.” Invert the plates, label, and incubate at 37˚C for 24 hours. Lab Day 3 ~ 30 minutes Students streak cultures from “Mix Plate” onto antibiotic plates. Invert the plates, label, and incubate at 37˚C for 24 hours. Lab Day 4 ~ 10 minutes Students observe & record results Clean-up all materials.