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July 1999


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Roger Dabbah <[log in to unmask]>
Reply To:
The Pharmaceutical Microbiology Mail List <[log in to unmask]>
Thu, 1 Jul 1999 09:04:37 -0400
text/plain (77 lines)

I agree with Richard Prince that I have not heard of microorganisms developing resistance to preservative  systems. I think it is a spillover from the notion that some microorganisms will develop resistance to antibiotics, which is a phenomenon well understood and researched. Rotating preservatives or cleaning agents has I believe been  recommended, in error, but has survived the test of time. If something is repeated long enough it becomes a "truth".

There is probably a selection  within a given population of outliers that become predominant, since there is less competition from the normal flora

          Roger Dabbah

>>> Anger_Claude <[log in to unmask]> 06/30/99 12:44PM >>>

We will always find organisms from the manufacturing environment getting
into our nonsterile products and developing resistance to preservatve
systems. There is only one answer to your situation and that is to make sure
that manufacturing cleans up their act here. In similar situations in my
pharmaceutical microbiology career that was the only answer. Above all, do
not accept a suggestion to reformulate the product to have a "better"
preservative system as the parabens have historically done an excellent job
preserving our products. You can save the organism and use it to challenge
future or other preserved products but remember that as soon as you culture
it on media the bacterial growth  will change its resistance to
antimicrobials from the original in the product culture.

Claude Anger
Director, Pharmaceutical Microbiology
Allergan, Inc.
[log in to unmask] 

        -----Original Message-----
        From:   [log in to unmask] [SMTP:[log in to unmask]] 
        Sent:   Wednesday, June 30, 1999 3:25 AM
        To:     [log in to unmask] 
        Subject:        [PMFLIST] Acetobacter spp.

        I am involved in an investigation of the contamination of a non
        liquid oral dosgae form.  The organism is Acetobacter pasteurianus,
xylinum &
        liquefaciens.  The organism seems to be resistant to parabens
(methyl &
        proply).  The pH of the item is 3-5.  The formulation has a fairly
high sugar
        content, mostly fructose.

        I was wondering if any of you have any experience with contamination
        this organism in pharmaceuticals?  What were the sources of the
        contamination.  How did you eradicate it?

        Pat Kunz
        [log in to unmask] 

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The PMFList ( is operated from
The Microbiology Network ( and supported by
our sponsors ( as a service to
the scientific community.

The PMFList ( is operated from
The Microbiology Network ( and supported by
our sponsors ( as a service to
the scientific community.