Biotech Updates

EFSA: Antibiotic Marker Genes Unlikely to Harm Human Health and the Environment

June 18, 2009

The European Food Safety Authority (EFSA) has published a statement that provides a consolidated overview of the use of selectable antibiotic resistance marker genes in genetically modified plants. EFSA's GMO and Biohazards Panels concluded that based on currently available information, the commonly used antibiotic marker genes nptII and aadA are unlikely to have adverse effects on human health and the environment. In their joint opinion, the Panels noted that the transfer of antibiotic resistant genes from GM plants to bacteria have not been shown to occur either in natural conditions or in the laboratory. According to the report, the key barrier to stable uptake of antibiotic resistance marker genes from GM plants to bacteria is the lack of DNA sequence identity between plants and bacteria.

The Panels, however, underlined the limitations in estimating exposure levels and the inability to assign gene transfer to a defined source. According to them, it is not possible to find out precisely from which organism a marker gene present in another organism may have originated.

 The GMO and Biohazards Panels also considered the clinical importance of the antibiotics to which the marker genes confer resistance. The gene nptII confers resistance to kanamycin, which is used by doctors as a second-line antibiotic for the treatment of infections with multiple drug-resistant tuberculosis (MTB). The GMO and Biohazards Panels stressed that "nptII has not been implicated in resistance to kanamycin in the treatment of MTB."

The complete story is available at Download a copy of the statement at