[Microbiology] Re: observing and counting bacteria within soft agar
(by yjgent from nospamcox.net)
Mon Dec 7 20:08:36 EST 2009
On 2009-12-07 14:05:19 -0500, Pavitra <pavitra.padmanabhan from gmail.com> said:
> Is there a simple way to count bacteria that are growing as a lawn in
> soft (top) agar? I'm working with E.coli. Would gram staining work?
Your question shows that you don't quite understand the basics of
microbiology cultures. There are many methods of counting bacteria,
some of which are counting colonies on agar, others require developing
a growth curve with a spectrophotometer.
You need to go back to your basic micro book and look up the topic of
colony counts. Learn how to make serial dilutions in a broth that will
support your bacteria and then how to plate a small enough aliquot to
give you countable colonies. Then you can calculate your bacterial
count per ml or what ever you are trying to count.
By the way, a "lawn" of growth refers to a confluent growth across the
whole plate, and not countable discrete colonies.
John Gentile MS, M(ASCP)
Laboratory Information Mgr.
VA Medical Center
yjgent from cox.net
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