Antibiotics / Cell Culture / Fungii infection

[ebarak at NSF.GOV]

Dr. Schuppenhauer:

If you are using cell culture grade antibiotic solutions from GIBCO, 
then it is not reasonable to think that the antibiotic solutions 
contain fungal spores.  If you are using non-cell culture grade 
materials, at the very least the solutions should be sterile filtered 
before use.

Rather than "fight the fungi with antimycotica," which are notoriously 
ineffective, I suggest you review your aseptic procedures.  The best 
approach is to make sure the infection does not occur in the first 
place.  In this regard, I would recommend AGAINST the use of any 
antibiotics.  Antibiotics can actually mask or cover up true 
procedural flaws.  If you have antibiotics in your medium and you 
"test for bacterial infection" soon after making up the medium, you 
will get a negative test result even if you have infections, because 
of the presence of the antibiotic. One of your respondents noted that 
the antibiotics can affect mammalian cell growth, and this is true.  
Yet another reason to avoid them!

Note also:  once you have fungal infection in your system, it may be 
difficult to eradicate it from the system itself.  Some fungal spores 
are resistant to normal autoclaving procedures.  Thus, even if your 
culture medium is "clean," your cultures could be re-infected from the 
hardware.  This is especially problemmatic with reactors where you 
cannot see inside (i.e., not made of glass), or where you have tubings 
and connectors.  I would recommend a chemical sterilant such as ALCIDE 
to thoroughly clean the reactor, and as I said earlier, a thorough 
review of your procedures to determine at what points along the line 
aseptic techniques may be compromised.

 
______________________________ Reply Separator _________________________________
Subject: Antibiotics / Cell Culture / Fungii infection
Author:  michaelrs at ezzeus.vmsmail.ethz.ch at NOTE
Date:    4/23/94 6:42 PM


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        We have comme across several cultivations of mammalian cells being "inf

cted"
by fibric material. The media we are using is made up from pulver and then 
sterile filtered, tested for (bacterial) infection. When running continous 
processes after 2/3 weeks or so we encounter clogging due to some fibres that 
attached to our reactor inside. Of course we did sterile testing before. To 
insure we can do the experiments we want to do we add antibiotics, 
penicillin/streptomycin/neomycin. All material is from GIBCO or Sigma, approved 
quality.

        Is it reasonble to believe that the fungii we saw under the
microscopes/scanning microscopes are imported through the antibiotics ?
        As antibiotics are produced from fungii, could it be that during
downstreamprocessing the spores are not totally removed, and end up in the 
suspensions ?
        Does anyone have had similiar experience/thoughts ? 
        Should I fight the fungii with antimycotica ?

                        Michael R Schuppenhauer
                        ETH Zurich, Switzerland
                        Dept. of Chem Eng
                        michaelrs at ezzeus.vmsmail.ethz.ch