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October 2019

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From:
Ravi Singh <[log in to unmask]>
Reply To:
The Pharmaceutical Microbiology Forum Email List <[log in to unmask]>
Date:
Wed, 2 Oct 2019 23:41:24 +0000
Content-Type:
text/plain
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Sent from my iPhone

> On Oct 2, 2019, at 4:26 PM, Donald English <[log in to unmask]> wrote:
> 
> ´╗┐Dear Richard,
> 
> Preservatives and chemical sanitizers are not effective against organisms in a biofilm.  The reason is that the lipopolysaccaride layer of 
> the biofilm protects the organisms from chemical attack.
> 
> Don
> 
> Donald J. English Microbiological Quality Consulting LLC
> Florham Park, New Jersey 07932
> Sent from my iPhone
> 
>> On Oct 2, 2019, at 8:27 AM, Richard Albert <[log in to unmask]> wrote:
>> 
>> I will take this opportunity to share the following.  The question I have
>> always had about USP <51> is how 'real' world it is.  Real world
>> microbiology is not a microbe growing in a Petri dish.  I have seen
>> formulations containing preservatives be very effective when evaluated
>> according to USP <51>.  However the preservatives were not effective when
>> the microbial growth was as a biofilm.  Has anyone else observed something
>> similar or evaluated preservative effectiveness against microbial growth as
>> a biofilm.
>> 
>> Richard A. Albert
>> Senior Microbiologist
>> Kleen Test Products
>> 
>> 
>> 
>>> On Tue, Oct 1, 2019 at 5:04 PM Robert Pritchett <
>>> [log in to unmask]> wrote:
>>> 
>>> Hello all,
>>> 
>>> USP <51> AET has the following text regarding preparation of test strains:
>>> 
>>> "Use standardized suspensions of test strains or prepare as stated below."
>>> "The viable microorganisms used in the procedure should be part of a
>>> freshly growing culture (e.g., in logarithmic growth phase) with the
>>> exception of A. brasiliensis spores."
>>> 
>>> I've encountered at least one contract lab who uses pre-made commercially
>>> available lyophilized cultures specifically marketed for AET. The
>>> lyophilized cultures are hydrated and then used for testing and that lab
>>> tells me they consider this the mentioned "standardized suspensions" from
>>> the USP text. The contract laboratory does perform proper method
>>> suitability using the premade AET cultures with passing results and I have
>>> seen the validation work for using AET pre-made cultures, but I still
>>> question the acceptability of the practice.
>>> 
>>> My personal opinions/talking points are as follows:
>>> - Why? It's simpler and more cost effective to start a fresh culture and
>>> any analyst with the title microbiologist should be able to adjust
>>> suspensions accordingly
>>> - Introducing recently desiccated, starved, frozen, and stressed cells as
>>> a challenge to a preservative system seems like a very bad idea - a weak
>>> preservative system might pass when it would otherwise fail when challenged
>>> with fresh cultures
>>> - The validation work cannot possibly represent the varied materials and
>>> preservative systems that may be tested for AET
>>> 
>>> At this time, I've requested laboratories performing AET for my site to
>>> always use fresh cultures.
>>> 
>>> With that said, I'm open to hear what others may say on the topic. Can
>>> anybody defend using pre-made commercial cultures for AET?
>>> 
>>> -RP
>>> 
>>> 
>>> 
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>>> 
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>> 
>> Science Advisory Board https://www.scienceboard.net/
>> 
>> Steris - http://www.sterislifesciences.com/
>> 
>> Charles River Laboratories - http://www.criver.com/
>> 
>> Veltek Associates, Inc - http://www.sterile.com
>> 
>> Microbiologics, Inc. - http://www.microbiologics.com
>> 
>> BD Industrial Media - http://www.bd.com/ds/
>> 
>> Boston Analytical http://www.bostonanalytical.com/
>> 
>> Associates of Cape Cod, Inc. - http://www.acciusa.com/
>> 
>> 
>> =================================
>> The nature of this service is to provide a medium for communication.  The specific statements and endorsements of individuals participating in the discussions are not necessarily those of The Microbiology Network, Inc., the PMF, or the sponsors of the list.
> 
> ------------------
> The PMFList (http://microbiologynetwork.com/pmflist.asp) is operated from
> The Microbiology Network (http://microbiologynetwork.com) and supported by
> our sponsors as a service to the scientific community.
> 
> Please take a second to visit our sponsors' web sites and say thank you for their support of this service.
> If your company would be interested in sponsoring this community, please contact [log in to unmask]
> 
> 
> 
> Science Advisory Board https://www.scienceboard.net/
> 
> Steris - http://www.sterislifesciences.com/
> 
> Charles River Laboratories - http://www.criver.com/
> 
> Veltek Associates, Inc - http://www.sterile.com
> 
> Microbiologics, Inc. - http://www.microbiologics.com
> 
> BD Industrial Media - http://www.bd.com/ds/
> 
> Boston Analytical http://www.bostonanalytical.com/
> 
> Associates of Cape Cod, Inc. - http://www.acciusa.com/
> 
> 
> =================================
> The nature of this service is to provide a medium for communication.  The specific statements and endorsements of individuals participating in the discussions are not necessarily those of The Microbiology Network, Inc., the PMF, or the sponsors of the list.

------------------
The PMFList (http://microbiologynetwork.com/pmflist.asp) is operated from
The Microbiology Network (http://microbiologynetwork.com) and supported by
our sponsors as a service to the scientific community.

Please take a second to visit our sponsors' web sites and say thank you for their support of this service.
If your company would be interested in sponsoring this community, please contact [log in to unmask]



Science Advisory Board https://www.scienceboard.net/

Steris - http://www.sterislifesciences.com/

Charles River Laboratories - http://www.criver.com/

Veltek Associates, Inc - http://www.sterile.com

Microbiologics, Inc. - http://www.microbiologics.com

BD Industrial Media - http://www.bd.com/ds/

Boston Analytical http://www.bostonanalytical.com/

Associates of Cape Cod, Inc. - http://www.acciusa.com/


=================================
The nature of this service is to provide a medium for communication.  The specific statements and endorsements of individuals participating in the discussions are not necessarily those of The Microbiology Network, Inc., the PMF, or the sponsors of the list.

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