Which is a better medium for preparing 0.5 McFarland turbidity standard for antibacterial activity assay? saline or Müller-Hinton broth?
Hello, better for A 0.5 McFarland standard prepare by mixing 0.05 mL of 1.175% barium chloride dihydrate (BaCl2•2H2O), with 9.95 mL of 1% sulfuric acid (H2SO4).
For bacterial suspension use saline water and also prepare above mentioned 1% sulfuric acid with the use of same water which you use for saline solution.
Good luck!
Hello, better for A 0.5 McFarland standard prepare by mixing 0.05 mL of 1.175% barium chloride dihydrate (BaCl2•2H2O), with 9.95 mL of 1% sulfuric acid (H2SO4).
For bacterial suspension use saline water and also prepare above mentioned 1% sulfuric acid with the use of same water which you use for saline solution.
Good luck!
If you want to measure the turbidity in media, I recommend you to set zero reading of spectrophotometer with 0.5 McFarland standard of bacterial suspension in your media i.e Müller-Hinton broth.
Hi,
You can use your culture media such as Nutrient broth, Müller-Hinton broth or any media.
You should use saline. Depending on what type of bacteria you want to test there could be some other choises - like for anarobic or fastidious bacteria.
See detailed info in standard methods for antibacterial testing: http://www.eucast.org/ast_of_bacteria/disk_diffusion_methodology/
Hi,
I second the opinion of Jane. You will have to do some bg study (specific to your bacteria) and choose the right media.
You may use saline or Müller-Hinton broth then you decide which one better works for your experiments.
I'd say it depends on what you're diluting your bacteria in. If you're making an AST where you dilute your bacteria in saline, use a McFarland made in saline. If you're doing some other experiment where you dilute your bacteroia in MH broth, go for a McFarland made in MH. It's all about controlling for the color and opacity of the medium you're looking at, just like you would make a baseline measurement on your spectrophotometer.
It is a function of intended use but saline is preferred because Muller Hinton broth contributes to the turbidity to be measured and could result in false conclusions
the same result because liquide Muller Hinton or saline solution will be tared
since you will be suspending bacteria after centrifugation in PBS or saline, PBS or saline should be used. Measuring absorbance values at OD: 600nm will provide readings. adjust to 0.08 to 0.1 for McFarlands 0.5
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