Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 21, 1997
Publication Date: N/A
Interpretive Summary: Sarafloxacin is a new drug that will be used in the poultry industry to prevent disease due to E. coli infection. Although the drug is useful for keeping chickens healthy, it should not be present, as a drug residue, in poultry products that are brought to market. Therefore, a simple, rapid test was developed to detect residues of this drug in food products. The test is 100 times more sensitive than a previously developed test and can be used to quickly screen many samples. Rapid tests such as the one described here should help producers, as well as government agencies, to screen poultry products for the presence of sarafloxacin residues.
Technical Abstract: Monoclonal antibodies were developed which bind sarafloxacin, a fluoroquinolone approved by the Food and Drug Administration (FDA) for use against E. coli in poultry. Splenocytes from mice immunized with a bovine serum albumin-sarafloxacin conjugate were fused with SP2/0 myeloma cells, and hybridomas secreting antibodies against sarafloxacin were selected and cloned. An enzyme-linked immunoassay (ELISA) was developed and fifty percent inhibition of control (IC50) values ranged from 7.3 to 48.3 ppb using sarafloxacin as the competitor. Tissue samples were spiked with sarafloxacin, and the average percent recoveries at 20, 50, and 100 ppb were 72.3, 75.2, and 88.7%, respectively. Monoclonal antibodies exhibiting high affinity for sarafloxacin were also characterized for their ability to detect five structurally-related quinolones. Some of the antibodies bind sarafloxacin, difloxacin, and trovafloxacin with nearly equal affinity despite structural differences. However, differences in chemical structure associated with enrofloxacin, norfloxacin and nalidixic acid were detrimental to antibody binding, resulting in 10- to 100-fold decreases in the relative affinities compared to that of sarafloxacin. The specificity and cross-reactivities of these antibodies are discussed in relation to three-dimensional, computer-generated molecular models of the fluoroquinolones. The data described here suggest that these antibodies can be used in an immunoassay format to rapidly screen poultry samples for the presence of sarafloxacin residues.