title: Improvement of capture efficacy of immunomagnetic beads for Campylobacter jejuni using reagents that alter its motility.
abstract: Previous studies using the immunomagnetic beads separation (IMS) technique have shown high detection limits of live campylobacters but low detection limits of formalin-killed campylobacters. The present study investigated if the addition of various concentrations of reagents that alter the motility of live Campylobacter jejuni could enhance the recovery of the organisms by IMS. The addition of 5% glycerol, 0.001% formalin, 10% polyethylene glycol, or 0.001% agarose in a buffer slowed down the movement of C. jejuni and increased the recovery of live C. jejuni, using beads coated with specific monoclonal antibodies (mAbs). The highest recovery yielded was 5.2- ± 3.3-fold with 5% glycerol at 10(5) colony-forming units (CFU)·mL(-1). The addition of 5% glycerol also improved isolation at lower concentrations of C. jejuni (10(2) to 10(4) CFU·mL(-1)) in buffer. The recovery by IMS of C. jejuni killed by 1% formalin was increased up to as high as 17-fold compared with the recovery of live organisms, as detected using a real-time polymerase chain reaction assay. The reagents investigated did not enhance the immunological reactivity of the mAbs to this organism. These results indicate that the addition of several reagents enhanced the capture of C. jejuni by IMS, which could be partially due to the slowing down of the movement or the altering of the motility of C. jejuni and to the increasing of the contact time between C. jejuni and immunomagnetic beads.
authors.affiliation: Ottawa Laboratory - Fallowfield, Canadian Food Inspection Agency, 3851 Fallowfield Road, Nepean, ON K2H 8P9, Canada. hongsheng.huang@inspection.gc.ca
authors.forename: Hongsheng
authors.initials: H
authors.lastname: Huang
authors.forename: Beverley
authors.initials: B
authors.lastname: Phipps-Todd
mesh_terms: D016123:Campylobacter jejuni / Q000235:genetics / Q000302:isolation & purification*; D005516:Food Microbiology; D018189:Immunomagnetic Separation / Q000379:methods*; D060888:Real-Time Polymerase Chain Reaction