Development of a Broad-Specific Competitive ELISA for First-Generation Cephalosporin Antibiotics in Animal-Derived...

The abuse of antibiotics, such as the cephalosporins in livestock and aquaculture productions, usually causes the widespread antibiotic resistance due to their growth-promoting effects. In this study, cephalexin was chosen as the hapten molecule to prepare a broad-spectrum rabbit polyclonal antibody for cephalosporin antibiotics. The obtained antibody exhibited broad cross-reactivity ranging from 0.05% to 100% with 10 cephalosporins. Based on this antibody, we developed a broad-specific indirect competitive ELISA (ic-ELISA) for cefalexin, cefradine, cefadroxil and cefazolin with the half maximal inhibitory concentration (IC₅₀) ranging from 0.72 to 2.99 ng/mL in working buffer. For animal-derived food samples with spiked cephalosporins, the ic-ELISA exhibited an excellent recovery ranging from 72.3% to 95.6%. To verify the accuracy of this proposed ic-ELISA, its detection performance was evaluated utilizing the high-performance liquid chromatography with satisfactory results. This study confirmed that: firstly, the prepared antibody can be used as a class-specific recognition element to develop immunoassays for cephalosporin antibiotics; and secondly, the developed ic-ELISA provided a new tool for broad-spectrum detection of first-generation cephalosporins in animal-derived foods.