How does Antibiotic Resistance Analysis (ARA) Bacteria Source Tracking work?
This method uses enterococci patterns of antibiotic resistance for identifying bacteria sources. The premise is that human fecal bacteria will have a high level of resistance to certain types of antibiotics, while domestic animals will have lesser resistance, but to a different suite of antibiotics and concentrations. Wildlife is expected to have little resistance to any antibiotic, since they are usually not exposed to any. For this method to be applied, a source library must be developed, using scat (feces) samples from potential contributors in the watershed (human, livestock, wildlife, etc). The known sources are analyzed for antibiotic resistance. The antibiotic resistance patterns in the source library are tested with known sources to calculate the “confidence” in the library, which is the rate at which the known bacteria sources are correctly classified. The unknown antibiotic resistance patterns in water samples are then compared to the source library to estimate the contributi
