Fluorescence detection of Staphylococcus aureus using vancomycin functionalized magnetic beads combined with rolling circle amplification in fruit juice

• Published in: Analytica chimica acta 2022-01, Vol.1189, p.339213-339213, Article 339213
• Main Authors: Wang, Yutong, Wang, Zhengzheng, Zhan, Zhongxu, Liu, Ju, Deng, Tingting, Xu, Hengyi
• Format: Article
• Language: English
• Subjects: Antibiotic-magnetic separation; Food Analysis - methods; Fruit and Vegetable Juices - microbiology; Juice; Nucleic Acid Amplification Techniques; Rolling circle amplification; Staphylococcus aureus; Staphylococcus aureus - isolation & purification; Streptavidin; Vancomycin
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2021.339213

Staphylococcus aureus is a common foodborne pathogen that can cause a suppurative infection after eating contaminated food. Detection of S. aureus plays an important role in the food industry. In this study, a strategy for the detection of S. aureus using magnetic separation (MS) technology combined with rolling circle amplification (MS-RCA) was proposed. The strategy used antibiotics to capture bacteria and employed RCA products as signal output probes. Vancomycin (Van), as a commonly used antibiotic, can recognize peptidoglycan on the cell wall of Gram-positive bacteria and can effectively identify target bacteria. Therefore, we prepared BSAylated-Van functionalized magnetic beads (Van-MBs) for the pre-enrichment of S. aureus. To ensure the selectivity of this method, we used biotin-pig IgG to bind S. aureus. In addition, to amplify the output signal of the MS-RCA strategy, we introduced streptavidin (SA) and successfully obtained the Van-MBs@S. aureus@biotin-pig IgG@SA@biotin-RCA probe complex and used the biotin-avidin-system (BAS) by combining magnetic separation technology and RCA technology to realize the enrichment and specific detection of S. aureus. Furthermore, by optimizing the experimental conditions such as the magnetic separation time and the amount of Van-MBs, the detection performance of this method was improved. Under the optimal conditions, the detection limit of this method for S. aureus was 3.3 × 102 CFU/mL in fruit juice, and it was less affected by other bacteria. [Display omitted] •RCA probe can produce amounts of ssDNA, resulting fluorescence signals amplification.•The method could be applied to the detection of Gram-positive bacteria.•The method is sensitive, specific, and simple for S. aureus detection.