MEMORANDUM 
DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE 
PUBLIC HEALTH SERVICE 
NATIONAL INSTITUTE OF HEALTH 
TO 
The Record 
DATE: September 4, 1979 
•from : Chief> 0 SRF, NIAID 
subject: Major Recommendations of Ad Hoc NIAID Working Group on Risk Assessment 
This meeting was convened on August 30, 1979 at the NIH with the 
stated main purpose of considering Falmouth Workshop Protocols I and II 
but also to extend to some related issues if time permitted. Dr. Stanley 
Falkow served as Chairman and the participants and NIH staff who attended 
are shown on the attached list. 
Protocol I addressed the colonization and transmission of plasmids 
from Escherichia col i K12 in the gastrointestinal tract of humans to 
other bacterial strains in the intestinal flora. The Working Group 
unanimously recommended that the NIAID not initiate new studies to 
pursue the investigations as written in Protocol I. This judgement was 
based on a review of data that existed at the time of the Falmouth 
Workshop, a consideration of some newer published data and the results 
of contracts that NIAID is presently supporting. As written by the 
Falmouth Workshop Participants, the experiments were to be based on E. 
col i K12 and this is now judged to not be a fruitful experimental model. 
It was a clear consensus of the Group that, based on the available data, 
it can be predicted that only negative results will be obtained and that 
limited resources could be better expended in other pursuits. Recombinant 
DNA experimentation using host-vector systems based on E. col i K12 was 
judged by this group as being completely without risk when conducted in 
compliance with good microbiological laboratory practices. 
Protocol II was designed to study the transmission of plasmids from 
£. col i K12, including Chi 1776, into the normal intestinal flora utilizing 
a germ-free mouse model. The Working Group unanimously supported the 
view that the NIAID should not initiate new studies for the Protocol as 
it was written but to rely on the present contracts to supply some 
additional data. This judgement was based on the same reasoning and 
data base considered for Protocol I; such further experimentation with 
E. col i K12 cannot be scientifically justified in 1979. 
The NIAID had also asked the Working Group to consider a recurring 
scenario. The issue is whether or not £. col i bearing a recombinant 
DNA molecule might thereby have its selective advantage enhanced and 
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