Harmonisation of Regulatory Oversight in Biotechnology Safety Assessment of Transgenic Organisms in the Environment, Volume 5..

I.1. BACTERIA: PATHOGENICITY FACTORS – 61

and whether attenuation has been shown to be sufficient so that the resulting
strain can be considered non-pathogenic.
The above points are illustrative rather than inclusive. Assessors must use good
judgment in utilising this list, recognising that additional examples may be pertinent to
the case at hand. Although there are a number of considerations that must be taken in the
evaluation of the pathogenic potential of genetically engineered bacteria, it is highly
unlikely that a pathogen will be inadvertently created from a non-pathogen lacking most
or the entire constellation of traits enabling the pathogenic lifestyle by combining
virulence factors.

Notes

1. The terms “genetically engineered micro-organism” and “genetically modified
   micro-organism” are used in different legislative systems for micro-organisms in
   which genetic information has been added or removed by techniques of modern
   biotechnology.


2. Toxins may also be low molecular weight metabolites; this type of toxins is, however,
   not taken into consideration in this chapter.


3. The following paragraphs describing adhesion of bacteria to various surfaces are
   restricted to the pili, adhesins and secretion systems of gram-negative bacteria.


4. Other aspects that have to be taken into account in various steps of the risk
   assessment include (but are not limited to) natural background levels; conditions for
   survival, persistence, growth and reproduction; mode of dispersal; potential for gene
   transfers, in particular genes associated with pathogenicity, toxicity or persistence;
   antibiotic resistance.


5. One factor that complicates this prediction is the influence of the condition of the
   host, e.g. the immune status of the host, on the effectiveness of a virulence factor.
   In regulatory discussions, however, this complication is usually evaded, as for the
   outcome of the discussion the conditions of the host is usually supposed to be
   “normal”.


6. For guidance on the detection of bacteria in soil, see OECD (2004).

References

Aebi, C. et al. (1998), “Phenotypic effect of isogenic uspA1 and uspA2 mutations on Moraxella
catarrhalis 035E”, Infection and Immunity, Vol. 66, No. 7, pp. 3 113-3 119, July.