Detection of bacteria from a cecal anaerobic competitive exclusion culture with an immunoassay electrochemiluminescence sensor

摘要

Abstract: A competitive exclusion (CE) culture of chicken cecal anaerobes has been developed and used in this laboratory for control of Salmonella typhimurium in chickens. The CE culture consists of 29 different species of micro-organisms, and is known as CF3. Detection of one of the CF3 bacteria, Eubacteria, and S. typhimurium were demonstrated using a commercial immunomagnetic (IM) electrochemiluminescence (ECL) sensor, the ORIGEN$+R$/ Analyzer. Analysis was achieved using a sandwich immunoassay. Bacteria were captured on antibody- conjugated 280 micron sized magnetic beads followed by binding of reporter antibodies labelled with ruthenium (II) tris(dipyridyl) chelate $LB@Ru(bpy)$-3$/$+2$PLU$/$RB@. The magnetic beads were then trapped on an electrode in the reaction cell of the ORIGEN$+R$/ Analyzer by a magnet, and the ECL was evoked from Ru(bpy)$-3$/$+2$PLU$/ on the tagged reporter antibodies by an electrical potential at the electrode. Preliminary IM-ECL assays with Eubacteria yielded a detection limit of 10$+5$/ cfu/mL. Preliminary IM-ECL assays with S. typhimurium yielded a similar detection limit of 10$+5$/ cfu/mL. !45