Scientific Documents

Opinion of the Scientific Panel on genetically modified organisms [GMO] on Genetically Modified Organisms on the use of antibiotic resistance genes as marker genes in genetically modified plants.

Opinion (244 KB)

Summary

Directive 2001/18/EC (EC, 2001) states that Member States and the Commission shall ensure that GMOs which contain genes expressing resistance to antibiotics in use for medical or veterinary treatment are taken into particular consideration when carrying out an environmental risk assessment. This is with a view to identify and phase out antibiotic resistance marker genes (ARMGs) in GMOs which may have adverse effects on human health and the environment.

The Scientific Panel on genetically modified organisms (GMO Panel) of the European Food Safety Authority (EFSA) has evaluated the potential risks associated with specific ARMGs taking into account their current usage in clinical and veterinary medicine, the likely occurrence of horizontal gene transfer from genetically modified (GM) plants to microbes and the potential impact of horizontal gene transfer where naturally occurring resistance to the relevant antibiotics exists in the microbial gene pool. These factors will impact on the likelihood of any adverse effects on humans or the environment of ARMGs used in GM plants.

The GMO Panel considers the frequency of horizontal gene transfer from GM plants to other organisms as very low for all ARMGs considered. This, in itself, is an important consideration with regard to any risk posed by the use of ARMGs. However, with respect to clinical importance the Panel has categorised ARMGs into three groups with different potentials for compromising human health and the environment. ARMGs in the first group include genes conferring resistance to kanamycin and hygromycin. In this group the nptII gene, which confers kanamycin resistance, has a 13-year history of safe use in food crops and resistance to this group of antibiotics is widespread in naturally occurring microbes in humans and the environment. The Panel is of the opinion that with regard to safety there is no rationale for inhibiting or restricting the use of genes in this category, either for field experimentation or for the purpose of placing on the market. The second group of ARMGs, which includes resistance to chloramphenicol, ampicillin, streptomycin and spectinomycin, should be restricted to field trial purposes and should not be present in GM plants to be placed on the market. Given their current importance in clinical usage, the GMO Panel recommends that ARMGs placed in the third group, which includes those conferring resistance to amikacin and tetracyclines, are not present in GM plants to be placed on the market or in plants used for experimental field trials.