I isolated 6 strains, in my opinion, they may be LAB. Because of their some characteristics: no spores formation, Gram positive, morphology of colony,...I haven't yet identified them exactly, I want to test their antimicrobial activity. I used the agar well diffusion assay with filtrated (0.2 micron) CFS of them on TSA (2% agar). the indicators are Vibrio parahaemolyticus and Staphylococcus aureus. But there is no inhibition zones. I refered to many articles, however, I haven't yet found out the information which mentions to resistant Vibrio by LAB's bacteriocin, therefore, I want to try to study about that.
What's wrong with my manipulation or these strains' bacteriocins?
Thank everyone!
Hi
commonly Gram negative bacteria such as Vibrio sp. is resistant to bacteriocin of LAB, may be due to LAB bacteriocin have narrow antibacterial activity
regards
Thank Mr. Heru - Pramono for your Suggestion
i also thought that LAB bacteriocin have narrow antibacterial activity. I was still isolating other LAB for inhibiting Vibrio sp.
Hi
The well difussion method not the best method to detect the inhibition activity of bacteriocin i suggest to use co-culture method
I have done this experiment before and found that using flow cytometry from a co-culture of a very large number of bacteria, including lactic acid bacteria and over 200 bacillus species, as suggested by Jehan above, works extremely well. I find that agar well diffusion, overall, is not that great for antimicrobial analysis especially for aerobic organisms. I have had much better luck using well diffusion with anaerobic organisms, grown in the agar itself. I have also done many experiments with Vibrio spp. and cell filtered supernatants in a 96-well plate monitoring the change in OD over a period of time, in addition to Staph spp and Clostridium. If you are able to, I would highly recommend doing a co-culture along with flow cytometry. If you look online, they also make smaller plates ( I forget the size) that have a .22 um filter separating 2 different cultures, but allows for any metabolites, antimicrobial compounds, etc. to pass through which might be of benefit as well. I hope this helps! The assay you are doing is very fun to do. Good luck
Thank you so much Mr. Jehan Abdulsattar and Mr. David Collins
The methods you suggested are surely very useful to detect inhibition activity of bacteriocin, however, there are not enough conditions to do experiment with the methods "co-culture" "Flow Cytometry" in the Lab I have worked at the present. Therefore, I only can do it with the well diffusion method, and luckily, it worked.
Thank you so much for your helps anyway.
I want to study about "Co-culture" "Flow cytometry". Could you give me some information or articles or documents about that? Thank you
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