Attack of the Superbugs Lab Introduction

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.