The European Food Safety Authority (EFSA) asked its Panel on Biological Hazards to identify, from a public health perspective, the extent to which food serves as a source for the acquisition, by humans, of antimicrobial-resistant (AMR) bacteria or bacteria-borne antimicrobial resistance genes, to rank the identified risks and to identify potential control options for reducing exposure.
The present extent of exposure to AMR bacteria was found to be difficult to determine, and the role of food in the transfer of resistance genes insufficiently studied. Nevertheless, foodborne bacteria, including known pathogens and commensal bacteria, display an increasing, extensive and diverse range of resistance to antimicrobial agents of human and veterinary importance, and any further spread of resistance among bacteria in foods is likely to have an influence on human exposure. By way of an example, a qualitative ranking of food (ending at point of purchase) as a vector of an AMR bacterium demonstrated the complexity of the problem and the extensive data requirements for a formal risk ranking.
In all cases where antimicrobial treatment in humans is indicated, resistance to the antimicrobials of choice is of clinical importance. Resistant Salmonella and Campylobacter involved in human disease are mostly spread through foods. With regards to Salmonella, contaminated poultry meat, eggs, pork and beef are prominent in this regard. For Campylobacter, contaminated poultry meat is prominent. Cattle are a major verotoxigenic Escherichia coli (VTEC) reservoir and resistant strains may colonize humans via contaminated meat of bovine origin more commonly than from other foods. Animal-derived products remain a potential source of meticillin-resistant Staphylococcus aureus (MRSA). Food-associated MRSA, therefore, may be an emerging problem. Food is also an important source for human infections with antimicrobial resistant Shigella spp. and Vibrio spp.
The principles that are applied to the prevention and control of the spread of pathogenic bacteria via food will also contribute to the prevention and the spread of antimicrobial-resistant pathogenic bacteria. As antimicrobial resistance in foodborne pathogens and commensals represents a specific public health hazard, additional control measures for antimicrobial-resistant bacteria may therefore be necessary. There are few examples of control programmes that directly control AMR as the hazard, using measures that specifically address food. In terms of impact, controls operated at the pre-harvest phase, for example, those aimed at the control and limitation of antimicrobial usage, are potentially the most effective and as such are capable of playing a major role in reducing the occurrence of AMR bacteria in food as presented for sale.
The development and application of new approaches to the recognition and control of food as a vehicle for AMR bacteria and related genes based on epidemiological and source attribution studies directed towards fresh crop-based foods, raw poultry meat raw pigmeat and raw beef are recommended.
Specific measures to counter the current and developing resistance of known pathogenic bacteria to fluoroquinolones as well as to 3rd and 4th generation cephalosporins found in a variety of foods and in animals in primary production now require to be defined and put in place as a matter of priority.
A major source of human exposure to fluoroquinolone resistance via food appears to be poultry, whereas for cephalosporin resistance it is poultry, pork and beef that are important, these food production systems require particular attention to prevent spread of such resistance from these sources.
If a full risk assessment for a specific food-bacterium-combination, in respect of AMR, should be undertaken, methodologies currently available for the risk assessment of foods require to be modified for uniform adaptation at both MS and EU level for the risk assessment of those combinations (including foods originating from food animals, fish, fresh produce (e.g. lettuce etc.) and water, as a vehicle for the transmission of AMR bacteria and related genes).
Overall, control of all the routes by which AMR bacteria and their related genes can arise in the human patient, of which food is but one such route, requires a response from all stakeholders to acknowledge their responsibilities for preventing both the development and spread of AMR, each in their own area of activity including medicine, veterinary medicine, primary food animal production, food processing and food preparation, as well as in the regulation of food safety.