-3- 
It is important to note that hospitals are containment environments, in 
which all of the workforce is trained to control infections, generally far 
better than that of biochemistry graduate students. Furthermore, many 
cloning experiments will be done in hospital departments. Both the recent 
violations of the guidelines were in Medical schools (Charles Thomas, at 
Harvard, and Boyer at San Francisco). 
3) Epidemic strains of IS. coli are well known and are a major cause 
of diarrhea in children and adults. Concern over them has been increasing 
in recent years, particularly with respect to infections of infants (Sack, 
1976 ). 
4 ) Most bacterial infections are of compromised individuals. For 
example infants are deficient in Immunoglobulin M and in several components 
of the complement system, making them more susceptible to certain infections, 
for example E. coli meningitis (Wilfert, 1978). A substantial number of 
patients in U.S. Hospitals receive immunosuppresin therapy which makes them 
much more susceptible to infection. Simililarly the aged are often much more 
susceptible. 
The Falmouth conference focused entirely on infection of healthy adults 
by K12 strains, an unrealistic and limited scenario. Even the results on 
transfer of genes was done in the absence of antibiotic therapy. However, 
in the real world the problem is clearly the danger -in the presence of 
antibiotics - of selection for recombinant plasmids due to their carrying 
genes for antibiotic resistance. (Levins, 1977). 
5) Pathogencity is not simply a property of an organism, but a relation- 
ship between a strain of organism and some particular host. The failure 
to shown increased pathogenicity in some particular host does not rule out 
increased pathogenicity. 
Tnus j£. coli strains possesing the capsular antigen K1 
are a major cause of meningitis among human neonates and infants. These 
infections have mortality rates from 40-80% (Glode et al , 1977). Those 
Infants that survive the infection often suffer developmental or eurological 
abnormalities. These strains are not uncommon in adults , but are rarely 
associated with disease. 
The introduction of a plasmid specifying potent mammalian hormones, 
for example, into meningitis strains of coli could very well increase either 
its pathogenicity or the actual damage done to the infected infant. 
6) In numerous well studied cases the pathogencity of E. coll strains 
for a defined host is associated with the presence of a particular plasmid. 
The spread of antibiotic resistance due to plasmids has become a major 
international health problem, and needs no review here. Similarly the 
production of enterotoxins coded for by plasmid genes are well known to 
be major determinants of pathogencity. It is also known that certain plasmids 
specify proteins, such as the K88 antigen, which affects the binding of the 
cell to a host tissue. This is a critical determinant for diarrheal 
infection in piglets. 
[A-297] 
