If you need high throughput capabilities, maybe it will be better a 96 well plate method using a respirometric approach ( XTT, Almar Blue..), you can test a lot of concentrations and to evaluate synergies.

Could you please explain more detail abou your question.

it is not very clear.

thanks

can i test the effect of antibiotic on mixed bacterial population if yes what the best method

Thanks in advance for any help

Dear Dr Geetha, I am agree with doctor Codony the best method is a broth dilution method, because some compounds does not diffuse in the agar especially non polar compounds. Colorimetric methods for MIC lecture are commonly used but some extracts have the ability of reduce the MTT, alamar blue because give a fluorometric lecture that can be used for obtain a quantitative MIC, but I recommend you complement MIC assays with Time kill curve assays for determinate microbicidal activity. With best regards

Agar disc diffusion method is more reliable.

Disc diffusion and cylinder cup assay has no meaning unless it is coupled up with tube dilution because diffusion is influenced by molecular weight and the medium used. Compounds with low molecular tend to move faster and heavy molecule compounds require greater concentration to diffuse at certain distance. Tube dilution in broth is very ideal because you could test both bacteriocidal and bacteriostatic activity. Streak some inoculum from MIC into fresh medium for growth. No growth indicates bacteriocidal activity and regrowth indicates only bacteriostatic activity.

Yes you can also use tube dilution for mixed cultures.

There are 2 ways usually available to antibiogram number one is Kirby-Bauer and another one is E-test.

each of them has advantages and disadvantages. for example antibiogram test or Kirby-Bauer is not recommended for anaerobic bacteria fastidious and slow-growing agents such as TB.

another method is E-test which is time consuming but effective for testing antibiogram test.Although this method is useful and can be switched to automated machine, it is not an expensive method.

overally, most practitioner still do not use the antibiogram resulting from labs (empiric therapy). However ,to use turbidometry method to check the smallest effective antibiotic (MIC) is a concern. As antibiotics are toxic agents for the body. the best choice is the less toxicity.

regards

What is plate assay

You definitely must try disk assay first. After screening with agar disk diffusion assay,

you can then evaluate the activity more with agar well diff. assay. 

I think disk diffusion is much better, it should be followed by MIC and MBC tests.

If you could perform time-kill test after that, it will strengthen your study.

Just, why not you tried to compare both methods as a pre-test (Pilot study) for your specific extract so that you become so confident and for the next researcher on your extract can also use your methods as an inputs. Regards!