The Effect of Acetyltransferases on 2 Strains of E. Coli
The Effect of Acetyltransferases on 2 different strains of E. coli
Introduction Scientists have recently discovered that resistance to antibiotics may not be such a new thing. Evidence of bacteria samples in Canadian permafrost proposes that these resistances have been around for at least 30,000 years (Luiggi 2011). In our required pre-lab reading, we learned tuberculosis is becoming increasingly drug-resistant, giving proof that bacteria can adapt to necessary changes in order to survive (Barry 2009). The addition of acetyltransferases, enzymes that help move acetyl groups, to bacteria can make it more resistant to antibiotics containing aminoglycosides (Norris 2010). An aminoglycoside is simply just an antibiotic whose structure consists of amino-modified sugars. These antibiotics are effective in fighting off gram-negative bacteria in patients with infections (Schussler 2012). The challenge given to the class was to test two unknown strains of E. coli, which were “potentially” resistant to an aminoglycoside antibiotic, and see how susceptible or resistant the E. coli would be to the antibiotics.
Hypothesis: Since Dr. Engin H. Serpersu added acetyltransferases to both the “unknown” strains of E. coli, only the aminoglycosides, kanamycin and amikacin, would be affected. Prediction: The zones of inhibition of kanamycin and amikacin would be smaller because of the effect that the transferases would have on them.
Methods
First every group in the class was given two agar plates. Each group streaked their two plates with a wild E. coli strain and then divided each plate into four sections. The control group, a disk with no antibiotics, was placed in one quadrant, while three types of antibiotics were placed in the other three quadrants of both plates, totaling six different antibiotics. The antibiotics we used were as follows: ciprofloxacin, tetracycline, kanamycin, amikacin, triple sulfa, and penicillin. The class received four more agar plates per group
Introduction Scientists have recently discovered that resistance to antibiotics may not be such a new thing. Evidence of bacteria samples in Canadian permafrost proposes that these resistances have been around for at least 30,000 years (Luiggi 2011). In our required pre-lab reading, we learned tuberculosis is becoming increasingly drug-resistant, giving proof that bacteria can adapt to necessary changes in order to survive (Barry 2009). The addition of acetyltransferases, enzymes that help move acetyl groups, to bacteria can make it more resistant to antibiotics containing aminoglycosides (Norris 2010). An aminoglycoside is simply just an antibiotic whose structure consists of amino-modified sugars. These antibiotics are effective in fighting off gram-negative bacteria in patients with infections (Schussler 2012). The challenge given to the class was to test two unknown strains of E. coli, which were “potentially” resistant to an aminoglycoside antibiotic, and see how susceptible or resistant the E. coli would be to the antibiotics.
Hypothesis: Since Dr. Engin H. Serpersu added acetyltransferases to both the “unknown” strains of E. coli, only the aminoglycosides, kanamycin and amikacin, would be affected. Prediction: The zones of inhibition of kanamycin and amikacin would be smaller because of the effect that the transferases would have on them.
Methods
First every group in the class was given two agar plates. Each group streaked their two plates with a wild E. coli strain and then divided each plate into four sections. The control group, a disk with no antibiotics, was placed in one quadrant, while three types of antibiotics were placed in the other three quadrants of both plates, totaling six different antibiotics. The antibiotics we used were as follows: ciprofloxacin, tetracycline, kanamycin, amikacin, triple sulfa, and penicillin. The class received four more agar plates per group
References: Cited Barry III, Clifton E., and Maija S. Cheung. "New Tactics Against Tuberculosis." Scientific American (2009): 62-69. Luiggi, Cristina. "The Age-Old Fight Against Antibiotics." The Scientist (2011). Norris, Adrianne L., Can Özen, and Engin H. Serpersu. "Thermodynamics and Kinetics of Association of Antibiotics with the Aminoglycoside Acetyltransferase (3)-IIIb, a Resistance-Causing Enzyme." Biochemistry 49.19 (2010): 4027-35. Schussler, Elisabeth, Jan Hudson, Monique Lemieux, and Sudhir Naswa. “Biology 148: Organization and Function of the Cell.” Laboratory Manual (2012). Figure 1 – Comparison of resistance of E. coli to different types of antibiotics