Simultaneous detection of Bacillus cereus and Staphylococcus aureus by teicoplanin functionalized magnetic beads combined with triplex PCR

Abstract

Bacillus cereus (B. cereus) and Staphylococcus aureus (S. aureus) are two typical foodborne pathogens. In this study, we proposed a new strategy that combined antibiotic with magnetic beads (MBs) and multiplex PCR (mPCR) to detect B. cereus and S. aureus in juice sample with high sensitivity and specificity. Teicoplanin (TEI) is a glycopeptide antibiotic which can identify Gram-positive bacteria. The polyethylene glycol (PEG) and bovine serum albumin (BSA) double-mediated teicoplanin functionalized magnetic beads (TEI-BPBs) were prepared for separation of target bacteria, and the triplex PCR was used for specific detection by nuc, cesB and flic gene. Under optimal conditions, the TEI-BPBs showed a good ability to simultaneously capture S. aureus (>83%) and B. cereus (>81%). The TEI-BPBs-mPCR assay efficiently detected target bacteria even in the presence of 105 CFU/mL non-target bacteria. The results showed that the limit of detection (LOD) of B. cereus and S. aureus in PBS and juice sample could reach 100 CFU/mL within 4 h. Compared with conventional methods, this method has lower LOD and shorter detection time. The results demonstrate that the constructed TEI-BPBs capture probe and triplex PCR could be successfully applied to the rapid separation and detection of B. cereus and S. aureus or other Gram-positive pathogens in food samples.