What does antimicrobial-resistant bacteria really mean?

Antimicrobial resistance is an expression that everyone in swine production has heard at least once but what does it really mean?  How are you as a producer or veterinarian affected?

Villalta NHF antimicrobial resistance 2017.gif

In this column for the National Hog Farmer, Dr. Carles Vilalta explains that beyond the definition of a bacterium that is not affected by an antimicrobial, there are two different approaches to think about resistance:

  • One is determined by the Minimal Inhibitory Concentration or MIC, which records the minimum medicine concentration required to stop the growth of the bacteria.
  • The other focuses on the presence of genes enabling the bacterium to counteract the effect of the antimicrobial.

These genes are usually present in a sub-population of bacteria called mutants. The video below created by Harvard Medical School shows how these mutants can develop, adapt, and survive the highest antimicrobial concentrations. (video length < 2min)