Each of the participating agencies is making the isolates available at no cost. ARS and CDC are also providing some additional funding in the way of personnel costs and facilities. This study can identify whether there is an emergence, increase, or change in resistance to any tested antimicrobial. This is a descriptive study, so analysis of any isolate does not mean that we can imply any relationship to isolates from other sources. Other types of studies, with specific methods for tracebacks, would need to be in place to answer relationship-type questions.
Some diagnostic laboratories collect similar information, but with a few key differences.
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.