Rapid and sensitive detection of Salmonella (O:6,7) by immunomagnetic monoclonal antibody-based assays.

An immunomagnetic technique to detect and identify Salmonella serogroup C1 has been developed. Monoclonal antibodies (MAbs) specific for the O antigen 6,7 of Salmonella lipopolysaccharide (LPS) coupled to magnetic beads were used to isolate the salmonellae. Captured bacteria were easily identified by acridine orange staining and measured by enzyme immunoassays with a conjugate anti-LPS MAb as the detector probe. The whole detection process required 2-3 h and the sensitivity was 10(3)-10(4) bacteria/ml. The presence of blood (10%, v/v) or stool (1%, w/v) components did not interfere with the immunomagnetic assay performance.