In most cases, diagnostic laboratory isolates are from clinically ill animals. These animals, and their isolates, probably do not reflect the general population of isolates. Clinically ill animals are more likely to have been treated with antimicrobials. In general, the isolates are likely to have been submitted because they are refractory to common treatments. In addition, the diagnostic laboratories do not aggregate data to a level higher than their service area, and there is a lack of standardization among laboratories in how they do antimicrobial susceptibility testing and how they define susceptibility.
Differences also exist in the kinds of antimicrobials used.
Our testing primarily targets healthy animals. Because of this, it is likely that we will see little resistance. However, if resistance is detected and confirmed, the nature of the origin of the samples will allow us to generate hypotheses that may be tested in more focused studies.