MEMORANDUM 
to Director, NIH 
DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE 
PUBLIC HEALTH SERVICE 
NATIONAL INSTITUTES OF HEALTH 
date: December 9, 1977 
from Chief, Laboratory of Viral Diseases, NIAID 
subject : Recommended change in revisions of the guidelines 
On page IV- 5 the statement "Individuals receiving antibiotics should 
not work with prokaryotic host-vector systems during therapy nor for 
seven days thereafter." needs revision. The primary purpose of the 
requirement is to avoid work with E. col i host systems while the 
person is undergoing changes in bowel flora that might facilitate 
colonization. As written, the sentence does not include sulfonamides, 
and does not exclude chronic antimicrobial regimens to which the 
bowel flora would be equilibrated. I propose the following substitution 
"Individuals receiving antimicrobial therapy expected to affect the 
bacterial flora of the gastrointestinal tract should not do recombinant 
DNA research involving prokaryotic host-vector systems during therapy 
nor for seven days thereafter. Examples where this restriction would 
not apply are persons on prolonged antimicrobial suppression such 
as for rheumatic fever prophylaxis or suppression of urinary tract 
infection.” 
Wallace P. Rowe, M.D. 
sg 
[Appendix A — 107] 
