Applying IDEXX SNAP Kits to Testing for Antibiotic Residues in Water

Antibiotics are an emerging environmental contaminant. Their presence is increasing in the environment due to excessive distribution of antibiotics to livestock and humans. The danger lies within the increased potential of antibiotic resistant bacteria. Antibiotics enter water through human, industrial, and animal waste resulting from treatment plants, hospitals, and confined animal feeding operations. CAFOs house a disproportionate number of animals in tight quarters and administer excessive amounts of antibiotics to prevent disease and promote growth resulting in excreted antibiotics through urine and feces. The manure produced harbors antibiotics that are dumped or leached into waterways. Current test methods take one week, require intense chemistry, and cost around $500 for a 1L sample. IDEXX SNAP kits are potentially a cheap, convenient, and quick on site alternative. These test kits are currently used to monitor the presence of antibiotics in milk. The purpose of this research is to determine if IDEXX SNAP kits have a viable application towards testing water.

Four variations of IDEXX SNAP test kits including Tetracycline, New Beta-Lactam, Gentamicin, and Sulfamethazine were used to test for the presence of 8 antibiotics within water. All samples were tested in triplicate. Individual solutions of 1% milk were spiked with each antibiotic and tested in the corresponding SNAP kit at 100ppb to serve as controls. Distilled water was tested in all SNAP kits as a second control. A stock solution of 1000ppb was created for each antibiotic, diluted further in distilled water, and tested at concentrations of 1ppb-100ppb. Each 100ppb spiked distilled water sample was also tested with the three non-corresponding SNAP kits to determine cross reactivity

Preliminary results indicate that tetracycline can be detected in water between the concentrations of 100ppb and 10ppb using the tetracycline IDEXX SNAP test. Below 10ppb tetracycline is not always detectable. Previous research reported positive tetracycline results in surface and ground water. Results from the remaining antibiotics are to be determined.  IDEXX SNAP kits are potential quick and cost effective tools to detect antibiotics in the environment.