The Antibiotic Epidemic Antibiotic Resistance
There are also concerns about the risk that the antibiotic-resistance genes used as selectable markers in GM plants may transfer to microorganisms that are human pathogens, adding to the increasing problem of antibiotic resistance in human pathogens. This problem is the result of widespread use of antibiotics in human and animal health. WHO, the Organization for Economic Cooperation and Development (OECD) and FAO have assessed the antibiotic-resistance markers used in transgenic crops as being safe. The risk of transfer of an antibiotic marker from a GM food to a human pathogen is considered remote. Nevertheless, the use of these antibiotic markers is being phased out. Other selectable markers that can be removed from the plant in the development phase are replacing them (Escalar, 2001).
Many bacteria in solid and liquid wastes from farm animals have been screened for resistance to antibiotics commonly used as growth promoters and or therapeutically to treat diseases (Sarmah et al. 2006). In one study, 80 terramycin resistance was exhibited by solid waste isolates, with 30 terramycin and 100 sulfamethazine resistance shown by liquid waste isolates (Bromel et al. 1971). However, the risk from animal to human being is minimal, with the exception of those personnel of agriculture or slaughterhouses who are in close contact with the animals and may develop resistant strains of bacteria of animal origin. It must be noted, however, that clear evidence of development of antibiotic resistance transfer from animal to humans has not yet been reported.
Some environmental risks can be reduced to an acceptable level by careful management. When biosafety reviewers determine that a proposed field test poses such a risk, they typically recommend that adjustments be made in the field-test release plan to address specific points of concern. For example, monitoring plans could be adjusted to be more comprehensive or provide different focus contingency plans could be called for when early termination of the field-test release was seen as a distinct possibility removal of an antibiotic-resistance marker gene before release could eliminate a concern that threatened to make approval unlikely specific labeling could be created and attached to seed containers to reduce concerns about inadvertent mixing of GMO and non-GMO seed.
Antibiotic-resistance (marker) gene (a) A bacterial gene coding for a protein that confers resistance to one or more antibiotics (such as ampicillin or kanamycin), used to identify transformed cells in the laboratory phase of research (b) a gene used as a selection marker to distinguish cells that have taken up foreign DNA from those that have not its action allows cells to survive in the presence of normally toxic antibiotic agents. Biosafety concerns include potential toxicity or allergenicity of the resulting protein and possibility of horizontal transfer from food or animal feed products to microorganisms in the human or animal gut, or the environment, which may compromise the therapeutic efficiency of clinically useful antibiotics.
After 5 years of intensive discussion Directive 2001 18 EC on the deliberate release into the environment of GMOs was passed in February 2001 (European Commission, 2001), which replaced Directive 1990 220 EEC. A commercial approval of GMOs will be given only for a 10-year period and can be extended for another 10 years. In addition, starting 2005 no commercial release of GMOs will be allowed, which contains antibiotic resistance marker genes, for which harmful impacts on human health and the environment are discussed (Sch tte et al., 2001). Directive 2001 18 EC requires a post-market monitoring of each approved GMO in order to detect unanticipated effects of such organisms to the environment and human health. Furthermore, labelling of GMOs is foreseen in this directive without giving details concerning traceability requirements for products, which contain GMOs or are derived from GMOs (Loureiro, 2003). The same relates to tolerance levels for unadventitious mixture of GM material with...
Whether the genome contains any known toxin genes. If the production organism is genetically modified, then additional considerations come into play regarding the nature of the modification, the characteristics of the donor organism with regard to potential toxigenicity, the presence of transmissible antibiotic resistance markers, and so forth.
Veterinary medicines in the environment. Rev. Environ. Contam. Toxicol. 180, 1-91. Bromel M, Lee, YN, Baldwin, B. (1971). Antibiotic resistance and resistance transfer between bacterial isolates in a waste lagoon. In Livestock Waste Management and Pollution Abatement. American Society of Agricultural Engineers, 1971. 283 p.
Interest to make it easier to determine whether the treated cells or tissues are in fact genetically modified. There is some concern that the use of antibiotic-resistance genes as markers in transgenic crops might cause or increase resistance to antibiotics in microorganisms that cause disease in humans and animals. In other words, could use of these genes increase the problem of drug-resistant super bugs Antibiotic resistance is a serious public health issue. However, scientists widely agree that the root cause of the problem is the overuse or misuse of antibiotics in clinical treatments and animal production. As such, the possibility that use of antibiotic-resistance marker genes in crops could pose a public health concern has been largely discounted.7 Nevertheless, food developers have started to pursue alternative types of marker genes, and in time it is likely that antibiotic-resistance genes will no longer be used. New marker genes and their products will be subject to the same...
Concern arose that GM plants containing antibiotic-resistance genes would, if consumed as food, present a risk to individuals taking the antibiotic as a therapeutic agent. Despite numerous detailed studies that unanimously concluded the risk was immeasurably low, and despite approval by the food safety regulatory agencies in numerous countries, public opinion remains opposed to the presence of antibiotic-resistance marker genes in foods. In response, developers of GMOs to be used as food are moving away from these genes. Ongoing efforts are under way to identify other types of genes useful as markers and to develop methods for removing marker genes before GM products get to the market. It is worth noting that even though the protein encoded by the nptII gene presents negligible biosafety risk, GMO designers are well advised to consider such concerns.
The potential risks of biotechnology on human health may include toxic reactions, increased cancer risks, food allergies, food contamination, and antibiotic resistance (Table 4.1). There is also concern that GMOs in animal feed might present a health risk for consumers, or for the animal itself. Consumers are also concerned about the long-term health effects of genetically modified foods. 5. Antibiotic Resistance. Use of an antibiotic marker gene in the development of GE crops may contribute to the growing public health danger of antibiotic resistance.