Q2ITD - Campbell Biology

Question

Use your results from question 1 to evaluate the effectiveness of vancomycin and teixobactin.

 

Treatment	Dose (mg/kg)	Log of number of colonies	Mean (                   )
Control	-	9.0,9.5,9.0,8.9	9.1
Vancomycin	1.0	8.5,8.4,8.2	8.36
	5.0	5.3,5.9,4.7	5.3
Teixobactin	1.0	8.5,6.0,8.4,6.0	7.22
	5.0	3.8,4.9,5.2,4.9	4.7

 

Step-by-Step Solution

Answer

The results indicate that teixobactin is a more effective antibiotic than vancomycin. Moreover, it is also observed that both antibiotics are more effective at a high dose than low dose.

Step 1: Outline of the experiment

Antibiotics (vancomycin and teixobactin) isolated from soil bacteria were administered to mice infected with MRSA (methicillin-resistant Staphylococcus aureus) to check the effectiveness of the antibiotics on S. aureus.

 

The colonies of S.aureus obtained from the sampled mice were then reported on a log scale.

Step 2: Teixobactin is more effective than vancomycin

The sample of the mice administered with teixobactin had fewer bacterial colonies than mice administered with vancomycin. At a low dose of both antibiotics, teixobactin-treated mice had 72.2 colonies, whereas vancomycin-treated mice had 83.6 colonies. 

 

Similarly, teixobactin-treated mice had 53 colonies at a high dose, whereas vancomycin-treated mice had 47 colonies. Thus, teixobactin-treated mice had fewer colonies than vancomycin.

 

The result indicates that teixobactin is more effective in killing or inhibiting S. aureus as compared to vancomycin.

Step 3: Antibiotics are more effective at high doses

When used at a higher amount, 5mg/kg, both antibiotics were more effective in killing the bacteria than at a lower amount (1 mg/kg). This is confirmed by the fact that fewer bacteria colonies were obtained from the sampled mice administered with a 5 mg/kg dose of antibiotic.

 

Thus, teixobactin and vancomycin are more effective at a higher amount than at a lower amount.