I am studying on antibacterial activity of lactic acid bacteria. I activated my bacteria cultures and test pathogens for two times during two days.
During my research on methodology, some researchers used supernatant part of bacteria. I wonder that, can I use either my bacteria or pathogens without any special preparing (so i used my cultures with their own broth solutions).
For this purpose, i spread my pathogens to blood agar as 100 uL, then drying, then i add my active bacteria in the wells.
Dear researcher
Following standard protocol, you should use an 18-24h culture of lactic acid bacteria, remove aliquots of cell-free supernatant, and use for antimicrobial activity testing. it is important to note that this supernatant will have a low pH and this may be the pathogen inhibiting factor in tests (indicator cultures); if that's the purpose, that's fine, but if you want to know if LABs have antimicrobial activity other than lactic acid production, then it's important to neutralize the supernatant broth before using them in the test wells.
Using the culture directly in the wells can result in a series of undesirable variables and difficult to assess the result. For example, contamination, differential culture growth in each well during testing, too much lactic acid produced...
In relation to cultures of pathogens, it is necessary to have the same activation procedure to obtain fresh cultures.
Every test of antimicrobial activity must be rigorously standardized and performed in the same way so that the replicates are valid and the results statistically reliable.
Success,
Jane
Check the methods used here https://www.sciencedirect.com/science/article/pii/S2095177915300150
A variety of laboratory methods can be used to evaluate or screen the in vitro antimicrobial activity of an extract or a pure compound. The most known and basic methods are the disk-diffusion and broth or agar dilution methods. Other methods are used especially for antifungal testing, such as poisoned food technique. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5762448/
Check the procedure used by this paper.
https://www.mdpi.com/2079-6382/9/5/225/pdf
Yes, you can use active bacteria such as probiotics for antimicrobial tests, but in my view, it is better to use lyophilization bacteria for these tests. Of course it depens on your object whether you want to evaluate the rate of bacteria activity as live bacteria or just to investigate the antimicrobial activity of the bacteria.
I think for a quick antimicrobial test it is possible, but what will be inhibiting? The lactic acid culture medium for LAB? or another component/metabolite produced by LAB?@
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