TP6 Degradates in the Environment
202 Oregon Ballroom
1:20 PM - 4:40 PM, Tuesday
() Isomeric Composition of Tetracycline Antibiotics in Liquid Manure at a Swine Animal Feeding Operation in Iowa.
Meyer, M1, Kolpin, D2, Beecher, K2, 1 U.S. Geological Survey, Lawrence, Kansas, United States2 U.S. Geological Survey, Iowa City, Iowa, United States
ABSTRACT- Analytical methods used for environmental assessments of tetracycline antibiotics may redistribute the proportion of the parent antibiotics and their epimers and isomers in liquid waste and water. In previous studies, chlortetracycline and tetracycline have been reported as the sum of the parent compounds and their epimers and isomers. In order to determine concentrations of parent compounds, epimers, and isomers individually, on-line solid-phase extraction and liquid chromatography/mass spectrometry with standard addition was used to characterize liquid waste samples collected from swine lagoons. Antibiotic residues were measured in liquid waste collected from the north and south sides of a lagoon in July, October, and November 2003 at a swine animal feeding operation in Iowa. The lagoon was drained between the October and November samplings. The primary antibiotic detected was chlorotetracycline and the dominant isomeric species of chlorotetracycline found were iso-chlorotetracycline, iso-epi-chlorotetracycline, and epi-chlorotetracycline. The concentrations ranged from 1,200 to 4,600 micrograms per liter for iso-chlorotetracycline, 1,100 to 2,700 micrograms per liter for iso-epi-chlorotetracycline, and<0.1 to 92 micrograms per liter for epi-chlorotetracycline. Chlorotetracycline was detected in three of six samples at concentrations from <0.1 to 1,400 micrograms per liter. Tetracycline and epi-tetracycline were detected in all the samples at concentrations from 71 to 210 micrograms per liter. Anhydro-tetracycline, a degradate of tetracycline, was detected at concentrations of <0.1 to 2.4 micrograms per liter. Lincomycin was detected in concentrations from 0.9 to 44 micrograms per liter. Spatial and temporal variations in concentrations were measured and will be discussed. More importantly, to understand the environmental distribution and fate of the tetracycline antibiotics and the relation between antibiotic residues and antibiotic-resistant bacteria, the isomeric species as well as the parent antibiotic need to be measured.
Key words: Tetracyclines, Antibiotics, Isomers, Animal Feeding Operations