Testing an Antibiotic Using a Disk Diffusion Assay - Kirby Bauer Method
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- เผยแพร่เมื่อ 14 มิ.ย. 2024
- At GoldBio, we make sure each of our products are thoroughly tested to the highest standards. In addition to a typical certificate of analysis (COA), we also test our antibiotics through a modified version of the Kirby-Bauer method, also known as the disk diffusion method. The test compares the antibiotic's ability to prevent bacterial growth to a common set of standards created by the Clinical Laboratory Standards Institute (CLSI) in order to assure its functionality at a certain concentration. As a control, we use a strain sensitive to the antibiotic to determine its effectiveness and a resistant strain to assure it is the correct substance. Each lot is tested with this procedure.
Visit our website at: www.goldbio.com
*Update November 2014*
Rather than going through the steps addressed in the video, this blog will just highlight important things to consider so you’re prepared to test when the time comes - www.goldbio.com/articles/arti...
*Update August 2017*
Here is the equipment used in this video:
-6 mm filter paper discs
-sterile petri dishes
-agar plates with no antibiotic
-sensitive and resistant bacterial cultures
-antibiotic to test and antibiotic for control
Other items out on the bench is a Bunsen burner, lighter, tube racks, thermometer, pipette, pipette tips, antibiotics solution, forceps, ethanol, flow hood (optional) and a marker to label discs
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this guy is the cutest thing I have ever seen. Super helpful, love the animations! Keep up the great work!
+Daniella McLean Thanks Daniella, we appreciate it!
I am so happy that you look happy! Most videos like this portray a monotone scientist, but you show the enthusiasm that I love!
this was very helpful for me! needed this for my project work! thank you!
This video is a life saver, thank you so much!!!
It is wonderful, you show something not available in the book, the technique. i will recommend this page to my friends. Thanks lot.
Thank you so much for this video. the way my microbio textbook explained this assay was so confusing!
Very useful, Thanks. The video looks cool especially the sound effects when showing the materials of the experiment ;-)
It's great that you are able to explain the science behind testing antibiotics. However, honestly it's cheaper just to buy new antibiotics in the first place. But it's a great way of testing your own homemade antibiotics
excellent demonstration,well explained.thanks
@ Deborah Frederick - Thanks for your question about the media. For the experiment shown, I was using LB agar, but depending on your standard bacterial species you can use whichever media is most appropriate for the organism. For this test, almost any media is fair game as long as you have good controls. Thanks for watching!
fantastic demonstration!
56 dislikes are from bacterias.
😂
You just secured my pass. Thanks man.
Thanks for you trial, very Helpful
@Alyssa Molina - Hi Alyssa. The quantity of antibiotic per disc is based on the minimum inhibitory concentration specific for that antibiotic, and is typically the same as the products found for medical testing. Best of luck with your project!
Hi! Thanks a lot for the video! What do you recommend when you are trying to find out the MIC of a novel substance?
Great video!
Thanks! Had been very useful. :)
Thank you so much for this video! It really cleared up the whole process for me! I’m doing an related experiment for my science fair project and I really needed to learn how to do this.
Thank you so much for such a useful and informative video. Actually, I want to check the antibiotic activity of Photorhabdus luminescens bacteria against gram positive bacteria. Can you give me some suggestions?
Patrick you're awesome!
THANK YOU FOR THE EXPLANATION
Great video! Really easy to understand and great tips. I was curious, though. You didn't specifically say what type of agar you are using. Are you using Mueller-Hinton agar, or can some other kind be used if you are just testing to see if an antibiotic is still good?
1) how did you prepare the antibiotic stock solution?
2) how did you know the desired concentration per disk
Also, if i want to prepare a 10 ml stock solution with concentration of 100 mg/ml should i just do that and then dilute it a working dilution of 1/100?
Loved your video! Thanks a million!!
Glad you liked it Randi. We are working hard on some new ones so stay tuned.
Hello, this video was a great help. We have done the disc diffusion method using normal blotting paper as discs. We have used (clorox, Phenol, Probiotic solution and Dettol) as reagents. We did not see any halos around the discs. We have used milk bacteria for this experiment. Please help us find out the answer to the problem. What kind of paper have you used as discs? Thank You!
I love it! Thank you so much sir!
THANKS A LOT SO SIMPLE AND INFORMATIVE .
In my microbiology class we had to do the Kirby Bauer method today. I happened to stumble upon your video when trying to find out more information about the method. For class, we also have to do a lab report based on our findings. Do you have any suggestions or tips on how to do the report?
Thank you really so much sir , this clip is very helpfull. God bless you sir
This video is very useful.
@ Khadijah Rafiq - Our apologies for the delay.
I have stocks of my sensitive and resistant strains that I streak out on a fresh agar plate, grow them up and pick a fresh colony into an overnight culture. Unfortunately a fume hood won’t be good for drying the discs because it’s pulling in room air instead of filtered air. I’d just let them dry covered on the bench for best results. Thank you for viewing and checking in with us!
***** Hi Joe - antibiotic effectiveness depends mostly on the organism being treated, and if they have any innate resistance to a specific class of antibiotic. While all antibiotics are grouped into a main category (chemical molecules that kill bacterial cells or prevent them from dividing), there are many different sub-classes that all work in different ways to achieve a similar goal.Some classes are just better at killing certain types of bacteria than others, based on their mechanism of action. When resistance is involved, things get even more complicated, which is why Antibiotics are a big research field for both doctors and microbiologists.
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this was so good thank you
Thank you for the video! :)
Thanks very much. We have a research and my teammates are off to an official business and im on my own and this helped a lot
Hi Laurice - That's great, we're happy to help!
very thankful for you thanx alot
Hello! Is it possible to adapt this method to see the effect of visible light (blue, red, ..) on bacterial growth/inhibition? If not, which other method can be utilised? Thankyou!
Could anyone answer a quick question? In comparison to the E test, what are the relative advantages of the Kirby Bauer method?
Can you please make a video about penicillin chemical assay by titrimetric method??
how can I know about the a mount of bacteria which are killed by antibiotic? (0.1 mm of hollow zone). could you explain me?
How would you grow the colony overnight? And also is a fume hood sufficient for drying the filter paper discs? Thank you
Is there any way to quantitatively determine the effects using this method?
good lecture. i ask about the assay used to detect antibiotic efficacy intracellular Vs intracellular bacteria
amgad mohammed sure
What type of filter paper did you use? I'm doing a bacterial growth inhibition project using filter paper to make the paper discs, but I don't know what type of filter paper is best to use. Also if I buy the discs would the 6mm size ones be the good to fit 5 of those in a 100 times 15 mm petri dish? Also, if you place the discs on the agar, put the lid back on, and then incubate them upside down, will the discs fall?
thank u
you are hero
you save me in my exam
كان اختبارك ميكرو عملي..؟😂
While incubating the plates having disc agar side should be up or down?
how do you compare the growth by recording the data? do we count the number of cultures per disk?
Hi! My research supervisor has advised me to place the disc on the NA plate that has been incubated overnight with well-spread bacteria culture, instead of placing the disc on the plate right after spreading the bacteria culture. She said the reason for doing this way is to observe the antibiotic killing the well-grown bacteria on the NA plate. The bacteria I am going to test against antibiotic is E.coli. However, I have not started my experiment. May I know how do you think of this suggestion? Can I have your advice? Thank you
Thanks for the video. How could you assure 0.5 log of bacterial concentration?
can this be used to test the growth of bacteria against a specific substance?
what is the pore size of the filter paper?
do we have to prepare bacterial lawn before hand? yes/no
Thank you!
Hi there, please help! I am conducting the antibacterial assay of my plant sample following the well diffusion method. But I have faced with a problem. Should I filter my plant sample with the help of 0.2 micron filter inside laminar flow cabinet before adding the samples into the wells. I found that when I filtered my sample, the concentration as well as the volume of my prepared sample also get decreased. I have also gone through severe literatures of my field but found no paper mentioning the use of 0.2 micron filter. So is it necessary to do so or I can skip this step?
Could you do something like for testing whether chlorine based pool water is better at killing bacteria than copper based pool water
hello. do you know what is the name of the antimicrobial disc with the code W 2.5 ?
What should the concentration be for the solution/broth with the antibiotic?
this is a good video, but you are taking about antibiotic.
what if i use disinfectant, what the optimum amount of disinfectant should i put on the disk, is it constant for all disinfectants or each one has its own parameters to perform its effect???
and thank you
Sir i want to know that how much mg of medicinal plants extract is to disslove in how much ml of dmso for well diffusion methode. Secondly sir that can we use water instead of dmso?
please explain about cylenders cup method
I have a question, im doing this quiz and the question is if my unknown is Gram negative; and my partner's unknown is Gram positive. Which would you expect to have the larger zone of inhibition around the penicillin antibiotic disk? Please help thanks
What gauge is the filter paper used? How did you prepare disk for drug?
thank you very much
muy bueno!
thanks
my question though is how does one extract the bacteria? like if i was curious about a bacterial infection on a wound...
Thank You!!!
Thank you
Can we do kirby bauer test with a bacterial colony from an agar plate instead of getting it from a liquid culture?
this is really helping :)
Sukhmandeep Kaur Thanks - we're glad to hear!
Can I use the disc immediately after adding the antibiotic without drying ??And thanks alot :-)
You try to give the video more brightness it will be great if you do
perfect thank you so so much :)
thank you!!!
how many dips in the fungi culture do i need to do, is there a maximum?
cool! how about antifungal and toxicity test? mind to demonstrate?
how do you sterilize the filter paper disc?
I have done a similiar project in school, but I used household ingredients like honey and mustard. Can I look at the zone of inhibiation to see which ingredient is best at killing bacteria? I'm doubting it myself because they have different viscosity, so coca cola for example should have a larger zone than honey even if they are equals when it comes to killing bacteria, right?
eldhand I would think that to get the mustard (or any thick substance) to absorb into the disk, you would need to dilute it in either vinegar or water to get it thin enough to compare directly to the cola. But it might be an interesting experiment to try!
+Gold Biotechnology, Inc. But then if you use vinegar you could not tell for sure if the activity is coming from the extract you are testing or from the vinegar itself...as the vinegar would alter the pH of the compound and most bacteria would not survive on such an acidic environment.
What kind of antibiotic should we used? Syrup or the capsule one? If capsule how can we apply it in using Kirby Bauer Method
Can we use any other antibiotic other than Ampicillin?
is this method limited only to mueller hinton agar?
@ Gold Biotechnology, Inc. I'm doing a similar Experiment for my senior EEI and was wondering if i could change this experiment slightly by replacing the antibiotics with household cleaning products and still have some success?
Jk Fuzzydragon Sure! I would think the household cleaners (as long as they’re liquids that could absorb into the paper disk) would work just fine in an experiment like this. Gels or foams may not be as easy, but might still be possible. Let us know if you try it out!
Hi. Im sort of new to microbiology (like zero experience) but we need to use this method for this project we have. Im wondering how do you determine the concentration/dilution per disk?
I just know your stem 😭😭
so intelligent of you.
Why not use the Mueller Hinton agar? I thought that's what you're suppose to do *confused*
at what temp should we incubate at 16-20 hours?
you are the best
superb..
if you dont have filter paper disc...... would cotton do ??
What happens if a non sterile swab was used ?
How to sterile that filter paper discs
What is use of antibiotic control ??
Can u provide me clsi guidelines for abst .
I have to do a project of my own and I've chosen to see if certain essential oils have an antibacterial effect, and I was wondering if I could use this method in the same way to test my oils? And would I have to dilute them or do you think can I just use the pure oil?
Hi Moonsong - that sounds like a very interesting experiment. I would think the oils would absorb into the disk’s okay, but you might need a control (plain mineral oil for example) to compare the effects of the essential oils to. I’d also recommend a known antibiotic as a positive control. You could try doing dilutions, but you couldn’t use just plain water, so it would be a little more tricky. Let us know how it turns out!
For the dilutions I plan to use a carrier oil :) Thanks for the tips :D
What is the size of you petri dish? How many antibiotic discs i can place in 90 mm petri dish?
Can i ask where to get a sample of a bacteria
Instead of using the loop can you use Q-tips
Hi Chardonnay - you can use q-tips as long as they’ve been sterilized in an autoclave first. Thanks for viewing!
I dont understand what control i would use
I'm a microbiology student😘😘😘😘it's my passion
excelente video
are the antibiotics liquid?
Does anyone have a list of the equipment that he used in the video?
Hi Ethan - we've added this list to the video description:
-6 mm filter paper discs
-sterile petri dishes
-agar plates with no antibiotic
-sensitive and resistant bacterial cultures
-antibiotic to test and antibiotic for control
Other items out on the bench is a Bunsen burner, lighter, tube racks, thermometer, pipette, pipette tips, antibiotics solution, forceps, ethanol, flow hood (optional) and a marker to label discs
We also created a supplemental blog post about Kirby Bauer here: www.goldbio.com/blog/120/old-antibiotics-wont-spoil-research-with-this-test
Thanks!
Thank you! :D
shouldnt the tweezer be flamed for a longer time than that?
+Sashene Brown No, as long as the tweezer is not on fire its ok. As soon as the alcohol evaporate the tweezer is not on fire anymore. The alcohol can also interfere on your experiment, so make sure that the tweezer is not on fire.
Oh okay thanks. it just seemed like he moved through the flame for less than a split second. :D