Science Buddies: "Ask an Expert"

Hi,
So this year I plan on researching how alternative remedies affect the gut microbiome compared to standard antibiotics.

I plan on using garlic and green tea for my alternative remedies and penicillin, ampicillin, and gentamicin as my antibiotics. I was wondering where I could get these products at a cheaper price. I'm also going to be using e. coli with a nutrient agar and the bb-12 bacteria with a brucella blood agar. Both are BSL 1 bacteria as I can only conduct this experiment in my school. With this I am going to be measuring their zone of inhibition. Would it be cheaper if I just bought the agar plates or make my own. Should I also cut down on my IV's?

If you have any suggestions it would be really helpful.

Hello!

To answer the first part of the question about purchasing the different products, it would be cheaper to purchase premade brucella blood agar plates, but the nutrient agar plates from E. coli will be cheaper to make yourself. The blood agar plates require a lot of additives that are expensive to purchase individually and in larger quantities than you'll end up using. However, for the nutrient plates, you can purchase LB agar powder and the plates at pretty low prices, so it's definitely cost effective to make them yourself especially if you will be using a lot of plates. My only concern would be sterilization of of the LB agar when pouring the plates. In a lab setting, we autoclave the LB agar to sterilize it, but a school may not have the equipment for this process. So, ultimately I would suggest purchasing the premade plates for the nutrient agar as well as the brucella blood agar.

For your IVs, I think having multiple antibiotics and alternative remedies is fine since there are different types of antibiotics and some work better with certain bacteria than others. Since you can place multiple antibiotic disks on one agar plate it doesn't make too much of a difference to have three disks versus five disks; I personally have seen up to twelve antibiotic disks on one agar plate before. As long as the zones of inhibition don't overlap, I would actually suggest that you do place your disks on the same plate to reduce variables in your project and reduce the number of plates you use.

However, I would suggest perhaps thinking more about which antibiotics you will use. Ampicillin is in the penicillin group of antibiotics, so your results may be very similar for those two zones of inhibition. So in that case, you could potentially only use one of them instead of both since the results may be redundant.

Let me know if you have any further questions!

kgrivera wrote:Hello!

To answer the first part of the question about purchasing the different products, it would be cheaper to purchase premade brucella blood agar plates, but the nutrient agar plates from E. coli will be cheaper to make yourself. The blood agar plates require a lot of additives that are expensive to purchase individually and in larger quantities than you'll end up using. However, for the nutrient plates, you can purchase LB agar powder and the plates at pretty low prices, so it's definitely cost effective to make them yourself especially if you will be using a lot of plates. My only concern would be sterilization of of the LB agar when pouring the plates. In a lab setting, we autoclave the LB agar to sterilize it, but a school may not have the equipment for this process. So, ultimately I would suggest purchasing the premade plates for the nutrient agar as well as the brucella blood agar.

For your IVs, I think having multiple antibiotics and alternative remedies is fine since there are different types of antibiotics and some work better with certain bacteria than others. Since you can place multiple antibiotic disks on one agar plate it doesn't make too much of a difference to have three disks versus five disks; I personally have seen up to twelve antibiotic disks on one agar plate before. As long as the zones of inhibition don't overlap, I would actually suggest that you do place your disks on the same plate to reduce variables in your project and reduce the number of plates you use.

However, I would suggest perhaps thinking more about which antibiotics you will use. Ampicillin is in the penicillin group of antibiotics, so your results may be very similar for those two zones of inhibition. So in that case, you could potentially only use one of them instead of both since the results may be redundant.

Let me know if you have any further questions!

Thank you for the information and suggestion. My next question is how would I dispose of the antibiotics, the discs containing the antibiotics, and the agar plates with the bacteria. I read some articles from the FDA saying I should add dirt to the antibiotic, seal it in a container, and then dispose of it in the trash can. Although, i am not really sure of it. For the agar plates I don’t know if I should autoclave them. What if excess antibiotics is left on the agar. I know the antibiotics can be flammable. But most BSL-1 bacteria are disposed of from a autoclave.

In my project i am researching how alternative remedies affect the gut microbiome compared to standard antibiotics. I am going to be doing the disc diffusion assay method for this experiment. My question is how would I dispose of the antibiotics, the discs containing the antibiotics, and the agar plates with the bacteria. I read some articles from the FDA saying I should add dirt to the antibiotic, seal it in a container, and then dispose of it in the trash can. Although, I am not really sure of it. For the agar plates I don’t know if I should autoclave them with the help of a professional. What if excess antibiotics is left on the agar. I know some antibiotics can be flammable. I am using penicillin and gentamicin for the antibiotics. But most BSL-1 bacteria are disposed of from a autoclave.

Hello student2021,

I've merged your most recent post in with the thread for your original post. Keeping the posts on the same topic together helps the experts who have been helping you see that you have follow-up questions. And, thank you for your patience - the experts are volunteers so they might not respond immediately. Good luck with your project!

Madeline
Moderator

Hi there!

After you're finished with your bacterial cultures and agar plates, you can soak them in a 10% bleach solution (1 part bleach to 9 parts water) for 1–2 hours. After you finish the bleach treatment, you can go ahead and throw everything into the trash. For the antibiotics, I would follow the instructions that you found from the FDA. You can also contact your local waste management authority to ask about guidelines for medication disposal in your area.

I hope this helps!
Katelyn