enumerating bacteria in a biofilm

Thu Apr 17 21:14:52 EST 1997

Probably one of the most commonly used protocols for doing viable counts of
bacterial cells in biofilms is to place the surface that the biofilm is
attached to, into a plastic vessel of appropriate size and subject it to
some length of sonication in a low intensity (50 Hz) sonic bath.  Typically
about 5 minutes is required to remove a majority of the bacteria from the
surface.  Most species don't have significant losses to their viability if
the period of sonication remains less than 10 minutes.  The surface and
diluent should then be vigorously vortexed prior to plating.  If you have a
particularly firmly attached biofilm such as from an industrial probe,
scraping the surface with a sterile scalpel blade and then placing the
coupon, blade and scrappings into a tube of diluent followed by sonication
and vortexing is quite effective.  With practice, the vast majority of
bacteria can be removed.  Give a shout back if you need a reference or more
Barry Wright

> From: "George O'Toole" <george at mbcrr.harvard.edu>
> To: biofilms at net.bio.net
> Subject: enumerating bacteria in a biofilm
> Date: Thursday, April 17, 1997 7:45 PM
> Hello.
> Can anyone suggest a protocol or protocols for removing bacteria from a 
> biofilm without killing them in order to determine viable counts 
> associated with a surface?
> Thanks in advance for any help.
> George O'Toole
> George O'Toole
> D1-219 Harvard Medical School 
> 200 Longwood Ave.
> Boston, MA 02115
> (617) 432-2268
> george at mbcrr.harvard.edu

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