Laboratory K-12 colonizing our guts?

Trond Erik Vee Aune via (by trondaun from
Thu May 3 07:50:37 EST 2007

DK wrote:

> In article <f1c8ep$dbo$1 from>, Trond Erik Vee Aune <trondaun from> wrote:
>>Dear all,
>>Yesterday we started discussing the possibility of our recombinant 
>>E.coli K-12 establishing themselves in our guts. I know there were some 
>>controversy around this in the 70's, but I haven't been able to find out 
>>what the conclusions were. Here are some specific questions:
>>* Can our modern laboratory K-12 acutally establish themselves in our 
>>guts, competing with our natural flora?
>>* What if after an antibiotics cure when the natural flora is greatly 
>>* Can expression of recombinant proteins from such bacteria cause 
>>problems with human health)
> I think the common explanation is that laboratory strains
> are too meek and fibble to survive competition with their 
> wild brothers. Whatever the reason, it does not seem to
> happen - people express all kind of bacterial toxins in E.coli
> (I personally did two) and no one ever died from lab E.coli yet.

Thanks for your reply, DK.

My thoughts went in similar directions, but do you know of any studies 
supporting our hypothesis that lab bugs are too weak to compete with 
natural gut flora? It would be a simple test to PCR screen for plasmid 
DNA from fecal matter. I would really like to see some conclusive data 
in either direction.

> A related question: how come the laboratory phages don't 
> seem to obliterate our gut flora? 

I guess that the phages would only wipe out their specific bacterial 
targets, and leave the rest of the flora, the majority, intact. I don't 
think we would notice if all our E.coli were temporarily lost.

Trond Erik

Trond Erik Vee Aune
Department of Biotechnology, NTNU

- Must be sad being a dyslectic, agnostic insomniac, lying
   awake during the night, wondering if there really is a dog

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