The World Health Organization has released new guidelines on the use of “medically important antimicrobials” (MIAs) in food animals. Here’s a list of their recommendations, along with the strength of each recommendation and quality of evidence behind it.

  1. We recommend an overall reduction in use of all classes of medically important antimicrobials in food-producing animals (Strong recommendation, low quality evidence)
  2. We recommend complete restriction of use of all classes of medically important antimicrobials in food-producing animals for growth promotion (Strong recommendation, low quality evidence)
  3. We recommend complete restriction of use of all classes of medically important antimicrobials in food-producing animals for prevention of infectious diseases that have not yet been clinically diagnosed (Strong recommendation, low quality evidence)
  4. We suggest that antimicrobials classified as critically important for human medicine should not be used for control of the dissemination of a clinically diagnosed infectious disease identified within a group of food-producing animals (Conditional recommendation, very low quality evidence)
  5. We suggest that antimicrobials classified as highest priority critically important for human medicine should not be used for treatment of food-producing animals with a clinically diagnosed infectious disease (Conditional recommendation, very low quality evidence)

They also included 2 “Best Practices” statements:

  1. Any new class of antimicrobials or new antimicrobial combination developed for use in humans will be considered critically important for human medicine unless categorized otherwise by WHO. 
  2. Medically important antimicrobials that are not currently used in food production should not be used in the future in food production including in food-producing animals or plants.

One thing that stands out is the low quality of evidence. Lack of strong evidence doesn’t always mean recommendations shouldn’t be made – important decisions sometimes have to be made before the evidence is solid. However, we need to make sure the evidence follows. Much of what’s stated above is common sense, to a degree; however, sometimes things that make sense at first don’t turn out to be completely true in the end. That’s one of the reasons CANresist is being developed – to help provide the evidence and help translate both best practice and evidence-based guidelines into action.

The table shown here (left) displays the WHO classification of medically important antimicrobials (MIAs).  It is worth noting that there are some differences between this classification and classification of MIAs used by Health Canada.