Dear Tahmineh, I don't think it gives a damage. But, to remove adherent or biofilm forming bacteria from surface, you can apply sonication and/or removing bacteria by cell scraper. Then, you can evaluate the number of bacteria on the surface by spreading onto plates.

Mert Sudagidan thank you!

Gentle shaking is advisable but vigous shaking is Not needed and studies showed its sequential damage

yes it will damage the cell. it is one of physical methods of killing the microbes

D. Bindu Thanks for your answer, then what is the best rpm for bacterial detachment? in many articles they just mentioned vigorously shaking, there is no more information related to rpm

it may differ for the gpc and gnb and specific for certain organism.

but with less than 0.5mm glass beads if you do 2250rpm it may work. if not between 3000-4000rpm

D. Bindu Thank you!

Around 2000rpm would be fine.

Ashwinikumar Singh Thanks for your answer!

use a standard vortexer for a minute or two... depends what are you doing you can always check using a microscope or staining your flask... what shaker gives you 13000 rpm (rpms are rotation per minutes and 13000 rpm is rather spinning in a centrifuge not shaking by a vortexer or homogrnizer) ... give more details and you can get a better answer

Jaroslaw Krol Thank you! actually the shaker I use has rpm! I know that vortex has numbers, in order to be more specific, all I want is to apply the speed which overcome the shear stress of gram negative and gram positive bacteria strains, so that I can detach bacteria from my surface. since our surface has a fluffy structure, detaching all bacteria trapped inside all layers is so important.