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 Conjugation Description 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 + Amp LB + Str 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 Activity: How to Store: Day: Time Needed: 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 ~ 30 minutes Students observe confirmation plates and prepare “Mix Plate.” Invert the plates, label, and incubate at 37˚C for 24 hours. (1) Students complete steps 34 – 47 on P.1.2.2. (2) Students begin construction of 3-D model. 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. (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.