Iam confuse between INT and PrestoBlue. As from literature they used mostly INT but one publication in the following link http://www.hindawi.com/journals/ijmicro/2013/420601/
Made me confuse about which one to select ?
Good day Alahdal
I am one of the authors of the article you referenced. Both INT (tetrazolium) or PrestoBlue (resazurin) will work to determine MIC's. It al depends on what you have in your lab. We found that PrestoBlue or any other resazurin based indicator work better for our experiments as the colour change is more prominent compared with INT. PrestoBlue also has the advantage over INT in that you can take measurements using florescence rather than just absorbance.
From the article: "The PrestoBlue provided an advantage in that the entire well was coloured, making visualisation of MIC values easier."
Hope this clears up your confusion?
Regards
thanks so mucc for your answer
how about Sodium 3′-[1-(phenyl amino-carbonyl)-3,4-tetrazolium]-bis-[4-methoxy-6-nitro] benzene sulfonic acid hydrate (XTT) can it be used to determined visual MIC values for p.acne .
as we have XTT in the lab.
one more things .about the contribution of color of honeys to absorption
iam testing three honeys with different color(brown ,golden, black). so when using the
growth indicator is there any step to carry to avoid the issues?
Dear Alahdal
XTT will work as a growth indicator, the problem is just that the colour change is not that prominent in my experience.
Viable bacteria will produce a red colour which can be tricky to see when you have dark samples as in the case with your honey. If testing a dark extract or sample, you can include a colour control (sample with bacteria, but without XTT), this can then be used to compare the actual XTT colour change.
Resazurin based reagents are blue in colour and change to pink red, so this difference is more visible than slightly pink to slightly red (like XTT).
One thing to keep in mind, these viability reagents all work on a different mechanism, thus if you want to look at something specific, you should choose accordingly.
I would first try the XTT, with an added colour control, to see if it works, before spending money on a different reagent. Resazurin powder is available from different suppliers, and not too expensive (its also cheaper than the ready-made reagents) .
Hope this might help?
thank for your answer .
i only want to determine the minimum inhibitory concentration (MIC)of each honeys
i am thinking to use Patton et al., 2005 method of microbroth dilution
the optical density prior to incubation (T0) subtracted from the OD after incubation (T96) at 600 nm.
but i am worry about the contamination of my samples from micro plate reader when it take the reading before incubation
so alternative i have plan to used the growth indicator
so can you advise for reference to know much about different mechanism of viability reagents .
dear phil
what do you mean i can used Patton et al., 2005 method without issuse
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