Screening for Penicillin Plasma Residues in Cattle by Enzyme-linked Immunosorbent Assay

Lee, H. J . , P . D. Ryu, H. Lee, M. H. Cho, M. H. Lee:Screening for Penicillin Plasma Residues in Cattle by Enzyme-Linked Immunosorbent Assay. Acta Vet. Brno 2001, 70: 353–358. In this study, we established a rapid prediction test for the detection of the cattle with violative tissue residues of penicillins. The recommended therapeutic doses of two penicillins, ampicillin (withdrawal time, 6 days) and amoxicillin (withdrawal time, 14 days), were administered to two groups of 10 cattle each. Blood was sampled and tested before drug administration and during the withdrawal period. The concentration of penicillins in plasma, determined by a semi-quantitative ELISA, was compared to that of internal standard (4ppb as penicillin G). The absorbance ratio of internal standard to sample (B/Bs) was introduced as an index to determine whether drug residues in cattle tissues are negative or positive. That means B/Bs ratio lower than 1 was considered residue positive and that higher than 1 negative. All 10 plasma samples from non-treated cattle showed negative results for both penicillins. Both penicillins were detected in plasma samples of cattle treated until the 3rd day of withdrawal period. The present study has shown that the semi-quantitative ELISA could be easily adapted for prediction of screening plasma residues for penicillin antibiotics (ampicillin and amoxicillin) in live cattle. Penicillin ELISA, plasma, cattle contamination, live animal test With the ever-growing world population, animal production practices have become more intensive and efficient, accompanied by increasing demands for drug treatment. Currently, approximately 80% of all food animals receive medication for part or most of their lives (Sternes jö et al. 1998). In the near future, nearly all animals bred in the world for food will receive chemotherapeutic and prophylactic agents of some type (Booth 1988). A survey of all violative carcasses in the United States in 1993 revealed that the most frequent drug residues were penicillin (20%), streptomycin (10%), oxytetracycline (10%), and sulfamethazine (9%) (Paige 1994). According to Canadian Animal Health Institute, penicillins were the most frequently detected residues in milk in most countries (Heeschen et al. 1996). Since 1986, Department of Veterinary Service, Ministry of Agriculture & Forestry, Korea has conducted National Residue Program (NRP) to sample meat and poultry for residue tests at the slaughtering establishments under its inspection authority and from import shipments at the port of entry. In 1997, a total of 45,000 samples comprising 10,000 beef, 23,000 pork, and 11,000 poultry meat were analyzed for five kind of antibiotics (penicillins and tetracyclines) and six sulfonamides. The results showed violative residues of tetracyclines, sulfonamides and aminoglycosides in beef, pork, and poultry meat. A few cases of minor allergic reactions (e.g., skin rashes) in individuals previously sensitized to penicillin G residues in milk and meat have been documented, as well as strong evidence linking a widespread agricultural use of antibiotics to an increase in antibiotic resistance among the animal and human pathogens (Dewdney et al. 1984; ACTA VET. BRNO 2001, 70: 353–358 Address for correspondence: Mun-Han Lee, DVM, Ph.D. Laboratory of biochemistry College of Veterinary Medicine, Seoul National University Suwon 441-744, Korea Phone: +88-31-290-2741 Fax: +88-31-293-0084 E-mail: [email protected] http://www.vfu.cz/acta-vet/actavet.htm