In my job over the years, I have had a few opportunities to interact with the medical profession concerning the use of antimicrobials and the role this use plays in the development of antimicrobial resistance. Recently I attended a meeting sponsored by the National Academies entitled Combating Antimicrobial Resistance: A One-Health Approach to a Global Threat. The “One-Health” descriptor meant that the meeting included topics on human and animal uses of antimicrobials.
Often these meetings can turn into finger-pointing events that end up villainizing animal agriculture. However, I found this particular meeting to lack much of the vitriol often piled on farmers and veterinarians. As usual, some of the anti-ag activist groups were represented, but there were limited opportunities for them to further their agendas. There was some finger pointing, but most of the meeting was guided towards describing the problems and working towards solutions.
During the meeting and in hallway discussions with infection-control physicians and researchers, I got the sense that these “front-line” clinicians are not very worried about antimicrobials used in animals. For the most part they are not very knowledgeable about such uses or how swine veterinarians strive to prevent pathogens from threatening pig health. One of their concerns was taken off the table due to the recent removal of the growth-promotion, feed-efficiency uses of medically important antimicrobials in animal feed by the US Food and Drug Administration. The role of the veterinarian in the decision-making process to use antimicrobials was also well received as we talked about the Veterinary Feed Directive.
Some issues that arose from meeting participants may someday affect veterinary medicine. One area of concern among meeting attendees was the fact that veterinarians make recommendations on the use of antimicrobials and also sell those drugs to the animal owner. There was a viewpoint that this should be avoided in order to prevent the veterinarian’s recommendation from being influenced by the profit motive from sales. In the United States, human medicine relies heavily on pharmacists. It would be difficult to totally revamp the distribution system for veterinary drugs, but it is an issue that may confront us in the future, perhaps via legislation or marketing requirements.
Another area of concern expressed during the meeting was the routine use of antimicrobials, whether in human or veterinary medicine. For humans, the unneeded prescriptions for uncomplicated upper respiratory infections, such as bronchitis, were cited. For food animals, the ongoing routine uses for prevention of diseases were brought up. An example given was the treatment of every group of animals arriving on a farm. One food-animal veterinarian went as far as to say that routine uses for prevention purposes represent a failure to adequately manage the disease through means other than antimicrobials. As uncomfortable as that statement might make us, it is incumbent on us to continually assess and determine the need for routine uses of antimicrobials.
A theme common to discussions on both human and veterinary medicine was the desire to measure antimicrobial use. Measuring use is a daunting task, but even more daunting is researching and developing the tools needed to interpret the data and make it meaningful. There are also important questions about where to measure, who gets access to the data, and who pays for the measurement. My fear is that use data could be manipulated to further restrict use without any scientific justification. Another fear is that the burden of measurement will be solely placed on the veterinarian and the farmer, taking up resources that could be used in other ways that may in fact benefit animal health more than simply knowing the amounts used. It would be much more useful if the knowledge derived from use data could be applied to specific circumstances of bacteria-drug interaction on the farm rather than the simple solution of using the use data as a benchmark that must be reduced every year.
One theory brought forth at this meeting was concerning what a speaker referred to as the “organismal soup” of bacteria. It is hypothesized that this “soup” is where horizontal gene transfer occurs between bacteria, thus allowing genetic material imparting drug resistance to be passed. The theory postulates that any introduction of antimicrobials into the soup, whether in humans, animals, plants, or the environment, will lead to resistance and potential transfer of genetic material. This is the sort of nebulous theory that is difficult and expensive to prove or disprove. This then becomes a tool for anyone wishing to disrupt animal agriculture with a theory that is subjective enough that it can’t be denied, but plausible enough to support further restrictions of antimicrobial use in animals.
I often dread attending these types of meetings due to the abuse often heaped upon animal agriculture. Fortunately, I found this meeting to be more practical and collaborative in its approach. I found it refreshing to openly discuss the resistance issues with physicians working in the area of infection control in human medicine. It seems to me that they want veterinarians to acknowledge that any health professional involved in the use of antimicrobials needs to recognize the potential consequences of such use, accept responsibility in the areas under their control, and work collaboratively across the One-Health spectrum.
Tom Burkgren, DVM