Development of a Rapid Multi-residue Assay for Detecting β-lactams Using Penicillin Binding Protein 2x

摘要

Objective To develop a rapid multi-residue assay for detecting 16 demanded by the European Union (EU). Methods A recombinant penicillin-binding protein(PBP)2x* from Streptococcus pneumoniae R6 was expressed in vitro and six β-lactams were conjugated to HRP by four methods.A rapid multi-residue assay for β-lactams was established with PBP2x* and HRP-conjugate. Results PBP2x* was expressed and purified successfully and the ideal HRP-conjugate was identified. The multi-residue assay was developed.After optimization,penicillin G,ampicillin,amoxicillin, cloxacillin,dicloxacillin,oxacillin,nafcillin,cephalexin,ceftiofur,cefaIonium,cefquinome,cefazolin, cefoperazone,cephacetrile,and cephapirin can be detected at levels below MRL in milk with simple pretreatment. Conclusion This assay developed can detect all 16 β-lactams demanded by the European Union(EU). The whole procedure takes only 45 min and can detect 42 samples and the standards with duplicate analysis.