My own guess is that FDA will pursue the Nanobacteria phenomenon aggressively
based on the Pyronema episode in the early 1990s. Pyronema is isolated from
cotton that is exported from China. It is highly EtO resistant, owing its
resistance, in theoretical large measure, to the fact that it is harvested
from fields where there are controlled burns to control pest populations.
Anyway, FDA asked the device industry to look at this issue, and "consider"
re-validating sterilization processes on the basis of there being an isolated
organism with a higher resistance than the prototype indicator, i.e., Bacillus
stearothermophilus. I don't know how many device firms actually re-validated
their sterilization processes.
The fact that it is both small and heat resistant is a problem. If we don't
know how to culture it, we don't know it's not there. If it is clearly proven
that Nanobacteria leaks through "sterilizing grade filters," it seems that the
solution to the problem is not to ignore it on the argument that "it's not
This gets back to a thread in the distant past about what to look for and what
not to look for in parenteral batches. My own view remains that organisms
proven to be pathogenic (so-called epidemiological risks) need to be
controlled. I therefore think it makes sense to study the organism in
additional cytotoxicity/toxicity systems to gauge its pathogenicity profile.
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