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December 2002

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Subject:
From:
Scott Sutton <[log in to unmask]>
Reply To:
The Pharmaceutical Microbiology Mail List <[log in to unmask]>
Date:
Tue, 10 Dec 2002 23:07:13 GMT
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Jeanne,

The passage is to be counted from the original ATCC culture

Lyo culture grown up for freezing - 1st passage
Frozen to weekly culture - second passage
Transfer from weekly for inoculum prep -  third passage

The concern being addressed with this is that USP was getting a lot of
reports about variability in results between labs.  One thought was
that the cultures were not in control, as some labs were using working
cultures that had been transfered successively for years.  This
requirement, already present in the Sterility Test, at least would
minimize the opportunity for variants to enter the inoculum.

In short then, any time you grow the organisms is a passage, you start
counting when you first manipulate the ATCC vial (assuming you streak
the culture or grow in liquid prior to freezing).

Scott Sutton

On Tue, 10 Dec 2002 12:51:13 -0500, you wrote:

>We're having difficulty agreeing on what "established" means.
>
>The USP states:
>The viable microorganisms used in the test must not be more than
>five passages removed from the original ATCC culture. For purposes of the test, one passage is defined as
>the transfer of organisms from an established culture to fresh medium. All transfers are counted. In the case
>of organisms maintained by seed lot techniques, each cycle of freezing, thawing, and revival in fresh medium
>is taken as one transfer.
>
>The dictionary defines establish as:  "to introduce and cause to grow and multiply".
>
>Therefore, an actively growing plate or tube would be an established
>culture.  Can you argue that an ATCC lyo is not "established", but your
>first inoculation of a broth/agar medium is?
>If that is true, than your resuspension and inoculation of the contents of
>an ATCC vial would not be a passage.  Correct?
>What about frozen and then thawed vials?  Established or not?
>
>Opinions?
>
>Jeanne Wilcox
>
>
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