RHA™ anti-Sulfadiazine monoclonal antibody, clone sd

A novel microbiological system in microtiter plates consisting of five bioassays is presented for the detection and classification of antibiotic residues in milk. The bioassays were optimized for the detection of beta-lactams (Bioassay B: Geobacillus stearothermophilus), macrotides (Bioassay M: Bacillus megaterium with fusidic acid), tetracyclines (Bioassay T: B. megaterium with chloramphenicol), quinolones (Bioassay Q: Bacillus licheniformis) and sulfamides (Bioassay QS: B. licheniformis with trimethoprim) at levels near the maximum residue limits (MRL). The response of each bioassay was interpreted visually (positive or negative) after 4-5.5 h of incubation. The system detects and classifies beta-lactams (5 mu g/l of amoxicillin, 4 mu g/l of ampicillin, 36 mu g/l of cloxacillin, 22 mu g/l of amoxicillin, 3 mu g/l of penicillin, 114 mu g/l of cephalexin, 89 mu g/l of cefoperazone and 116 mu g/l of ceftiofur), tetracyclines (98 mu g/l of chlortetracycline, 92 mu g/l of oxytetracycline and 88 mu g/l of tetracycline), macrotides (33 mu g/l of erythromycin, 44 mu g/l of tilmicosin and 50 mu g/l of tylosin), sulfonamides (76 mu g/l of sulfadiazine, 85 mu g/l of sulfadimethoxine, 77 mu g/l of sulfamethoxazole and 87 mu g/l of sulfathiazote) and quinolones (94 mu g/l of ciprofloxacin, 98 mu g/l of enrofloxacin and 79 mu g/l marbofloxacin). In addition, the specificity values were high for B, T, Q (99.4%), M (98.8%) and QS (98.1%) bioassays. The control of antibiotics through this system can contribute to improving the quality and safety of dairy products. (C) 2019 Published by Elsevier Espana, S.L.U. on behalf of Asociacion Argentina de Microblologia.

The occurrence and distribution of 14 antibiotics in the surface water and sediment of Nansi Lake's inflowing rivers were studied. The concentrations of the antibiotics in the sediment and water were not detected (ND)-193,440 ng kg(-1) and ND-694 ng L-1, respectively, and ofloxacin was identified as the main antibiotic. The target antibiotics were identified at decreased levels in the study area compared with the inflowing rivers of other lakes. The decreased antibiotic concentrations resulted from the dilution effect, strong biodegradation, and rapid photolysis during the wet season. The spatial variations were due to the differences in regional contributions; the concentrations of antibiotics from lining and Peixian were the highest. Antibiotic pollution in different seasons originated from different sources; pollution levels were determined by water levels and rainfall as well as complicated runoff generation and confluence mechanisms. Based on the risk quotients, ofloxacin, sulfamethoxazole and sulfadiazine were identified as the main antibiotics that contributed to high ecological risks. Algae and aquatic plants were the main model organisms exposed to these risks. This study has great significance for environmental prevention and the control of antibiotic contamination in Nansi Lake, which is an important water transport channel and the main impounded lake for the eastern route of the south-to-north water diversion project. (C) 2019 Elsevier Ltd. All rights reserved.