Scott Sutton recently posted a request for information about
'Nanobacteria'. Yesterday, I received a call for information from a
colleague at a local, licensed biopharmaceutical company in which he told
me that FDA had just questioned him about this 'genus' which he'd never
heard of. I did a 'Yahoo' search and there are a number of URLs listed in
addition to the PNAS reference which Jerry Masover provided. I thought I'd
provide a short summary of what I learned:
Nanobacteria are coccoid bacteria (Nanobacterium sanguineum gen. et. sp.
nov.)which were isolated from sterile, commercial FBS by a research group
at the University of Kuopio, Kuopio, Finland around 1996. They can pass
0.1 uM filters although they have cell walls and are highly heat-resistant.
They were not culturable in standard microbiological media but could be
cultured under cell culture conditions (with or without mammalian cells,
5-10% CO2). Multiplication could be prevented by gamma irradiation and high
doses of aminoglycoside antibiotics and other agents. They have been
isolated from more than 80% of commercial FBS and newborn bovine sera and
are the most common contaminant present in cell cultures. It is postulated
that this may be the reason why only about 10% of FBS batches support cell
cloning. They are cytotoxic to mammalian cell culture in high
concentrations relative to the mammalian cells by triggering cells that are
normally phagocytic to engulf them. "These organisms seem to be one of the
causes for cell vacuolization, poor thriving and unexpected cell lysis,
problems not rarely encountered in mammalian cell culture and often
attributed to cell senescense." They are not detectable with present
sterilty testing methods. The organisms have been found in both human and
cow blood. The authors have suggested an association between these
organisms and the formation of kidney stones.
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