Attack of the Superbugs Lab Introduction
Mrs. StewartMedical Interventions
Superbugs• What is a
“superbug”?– Bacteria that
have become stronger and less responsive to antibiotic treatment
How can bacteria share resistance?Genetic Transfer
MethodDescription
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 + 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 ScheduleDay: 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 ~ 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.