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Re: Bacteriophages in microbial fermentation plants
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Title: Re: Bacteriophages in microbial fermentation
plants
Tony,
Below are my answers to some of your
questions.
I have had phage problems develop during
scale up of a fermentation process I was working on a few
years ago. Most phage are very strain specific, so a good
understanding of the strain in your cell bank is important.
Never assume that your strain is the same as another isolate
of the same species.
Rande
On Mon, 3 Jan 2005 20:09:02 +0000 "Tony Christensen" <toch@pharmprotech.dk>
writes:
> Dear Forum,
> > A few questions regarding bacteriophages (phage) in microbial > fermentation plants: > > 1. What precautions are normally included in the design and layout > of microbial fermentation plants for manufacturing biopharmaceutical > API's in order to avoid phage infections from the surrounding environment. General facility design for aseptic processing should be used. Existing facility design for fermentation and/or cell culture area should protect the process from environmental contamination. I do not know of phage that is an
environmental airborne contaminant (usually
in water). A bacterial strain carrying the new phage
would need to grow and shed the phage. It is possible that a
plant operator could be a carrier of a contaminating strain (similar
to problems with murine cell culture and mouse
parvovirus).
> 2. What cleaning/sterilization methods are applied in order to > ensure that phages are effectively removed from multi product fermentation > equipment for manufacturing biopharmaceutical API's. > > A/ between fermentation batches even if no phage infection is detected Standard cleaning procedures
for any fermentation/cell culture equipment should be adequate. Most
of these have been developed to effectively sterilize (both bacteria
and virus). Of course validation of your equipment and
procedures is always required. If phage is a known concern in
your process, it would be a good idea to include a discussion
of phage inactivation in your validation protocol (I expect
that normal sterilization indicators are more resistant than your
phage).
> B/ after a detected phage infection Same as above ... but if is documented
that there was a known contaminant, a second cleaning of the
production facility is a good idea. If you have a more
thorough cleaning SOP (such as for campaigning between products) -
you should document that you have done something extra for the
"known
contaminant".
> > 3. If a strain that is knowingly infected with a well defined phage > - such as e.g. the lambda DE3 phage system that is widely used in E. coli - > is used for a fermentation batch, what cleaning/sterilization methods or > other precautions are or should be taken to prevent infection with this > phage of the following fermentation cultures for manufacturing of > biopharmaceutical API's. I do not think that BL21 (DE3) contains the
complete phage and sheds virus. Even if it does, it is specific
for it's E.coli host strains and I have never heard of this being a
problem.
> 4. What general and specific phage detection methods are in use in > fermentation plants for manufacturing of biopharmaceutical API's. I have not heard of anyone making an issue
of this, unless you have a problem with the fermentation process
(irreproducible growth or lysis). Remember that many species
of bacteria are almost always carrying multiple phages (including
common fermentation strains in pharmaceutical and food industry).
There is no concern with phage being harmful to humans, just treat
it as part of the normal "Host Cell
Protein".
Do not worry about it unless you know
that you have a problem!
I found a good discussion of phage problems
and control methods in cheese production at the following web
site : http://www.foodsci.uoguelph.ca/cheese/sectiond.htm (see section
7.7)
> Thanks in advance > > Tony Christensen > Consultant - PharmProTech > toch@pharmprotech.dk > Denmark > > > |
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