Are we any closer to understanding antimicrobial resistance (AMR) and its relationship to cattle than we have been in the last five years? I’m not so sure, but what I do know is that there are a lot of anti-agriculture and pseudo-science groups who want to take what little data there is on antimicrobial resistance and food animals and extrapolate it to mean that piece of beef on your plate is a dangerous risk.

In late May the Beef Cattle Institute (BCI) of Kansas State University hosted the International Symposium on the Use of Antimicrobials in Cattle. International and U.S. experts discussed, debated and even vented over the sparse data on the subject of antimicrobial use in cattle and effects on resistance in humans.

 We have no data on the exact quantity of antimicrobials “consumed” by different classes of animals and what these antimicrobials were used to treat or the outcome of that treatment, says conference organizer Hans Coetzee, BVSc, Cert CHP, PhD, Dipl. ACVCP, Kansas State University. “It is noteworthy that this knowledge is also deficient in human medicine,” Coetzee says. “So without knowing how much drug we use and if these are even making a difference, in some cases I would contend that it is very, very dangerous to make ‘cause and effect’ relationships with regard to drug use and resistance.”

Conference co-organizer Mike Apley, DVM, Phd, Dipl. ACVCP, Kansas State University, says there are some examples of excellent antimicrobial guidelines on the human side, but they often contain a clause something to the effect “that the needs of the individual patient may take precedence over these guidelines.” “These are wiggle words to still do whatever you want,” he says. “A big difference between the human medicine and veterinary medicine antimicrobial use situations is that the human side is not facing having their uses legislated away.”

Coetzee explains that although “historical” bacterial isolates exist from before the advent of antimicrobials, we do not have a handle on what “baseline” antimicrobial resistance levels looked like. We know that for the most part resistance does not suddenly arise when the drug is discovered, but that this is preexisting at some low levels in the population. “The key question is how the widespread use of the drug gives rise to dissemination of the resistance clone,” Coetzee says. “We also don’t know how this dissemination would ultimately impact the human population. Instances of AMR infections in humans that arose because bacteria-acquired resistance in animals remains undefined and this is the major contention. Until we resolve this issue we will continue to be misled by folks with an agenda rather than the people with facts to substantiate their opinion.”

“It amazes me that we have to produce science to defend a tool that has already gone through rigid safety and efficacy trials for approval,” says Dan Thomson, DVM, PhD, Beef Cattle Institute director. “However, an activist group needs no data to get it pulled off the market through legislative action.”

Thomson says, however, that that does not let producers and veterinarians off the hook as far as being responsible. “We need to condemn those in our industry or profession who are doing wrong. We need people to understand that we all represent each other. One bad apple does spoil the whole bunch when it comes to today’s media and technology.”

Next issue: September 2009