Antibiotic Resistance Lab Report
Bio-112
Antibiotic Resistance Experiment
Lab Partners:
March 10, 2010
When we initially started the bacteria antibiotic experiment on February 10, 2010 our team
selected e-coli and Rifampicin (Rb5) to find out the level of resistance e-coli would build
towards this antibiotic. When we first checked our agar dish on February 15, 2010 we noticed
two circles for the zone of inhibition the small circle was 1.5 cm and the medium circle was 3.00
cm. Two days later when we checked it again the small circle had stayed the same at 1.5 cm but
the medium circle was 3.02 cm. The changes were minimal during that first week. Week two
however on February 24, 2010 the small circle had become smaller it was now 1.3 cm and the
medium circle was 2.3 cm. E-coli was building resistance to Rb5 based on the smaller zone of
inhibition. During our last check on March 1, 2010 the medium circle was completely gone so
e-coli had become partially resistant to Rb5 and the small circle was only 2.3 cm. With time this
goes to show how bacteria become resistant to antibiotics. The e-coli may have mutated or when
spreading the antibiotic on the agar dish if we missed any areas the e-coli wouldn’t have been
killed by the antibiotic. Once a bacteria picks up the gene that it’s resistance to an antibiotic it
can pass it on to its daughter cells or to other bacteria via horizontal gene transfer so now you
have a colony of bacteria that’s resistant to the antibiotic. E-coli is known to reproduce at a high
rate which is why we were able to see these results so quickly in just three weeks. This
experiment helped us realize how important it is to take your full dose of medications when
you’re sick to help avoid bacteria becoming resistant to antibiotics and to also not take
medication if you’re not showing the actual symptoms correlated with a bacterial infection.
Antibiotic Resistance Experiment
Lab Partners:
March 10, 2010
When we initially started the bacteria antibiotic experiment on February 10, 2010 our team
selected e-coli and Rifampicin (Rb5) to find out the level of resistance e-coli would build
towards this antibiotic. When we first checked our agar dish on February 15, 2010 we noticed
two circles for the zone of inhibition the small circle was 1.5 cm and the medium circle was 3.00
cm. Two days later when we checked it again the small circle had stayed the same at 1.5 cm but
the medium circle was 3.02 cm. The changes were minimal during that first week. Week two
however on February 24, 2010 the small circle had become smaller it was now 1.3 cm and the
medium circle was 2.3 cm. E-coli was building resistance to Rb5 based on the smaller zone of
inhibition. During our last check on March 1, 2010 the medium circle was completely gone so
e-coli had become partially resistant to Rb5 and the small circle was only 2.3 cm. With time this
goes to show how bacteria become resistant to antibiotics. The e-coli may have mutated or when
spreading the antibiotic on the agar dish if we missed any areas the e-coli wouldn’t have been
killed by the antibiotic. Once a bacteria picks up the gene that it’s resistance to an antibiotic it
can pass it on to its daughter cells or to other bacteria via horizontal gene transfer so now you
have a colony of bacteria that’s resistant to the antibiotic. E-coli is known to reproduce at a high
rate which is why we were able to see these results so quickly in just three weeks. This
experiment helped us realize how important it is to take your full dose of medications when
you’re sick to help avoid bacteria becoming resistant to antibiotics and to also not take
medication if you’re not showing the actual symptoms correlated with a bacterial infection.