Characterisation of a SapYZU11@ZnFe 2 O 4 biosensor reveals its mechanism for the rapid and sensitive colourimetric detection of viable Staphylococcus aureus in food matrices

• Published in: Food microbiology 2024-09, Vol.122, p.104560
• Main Authors: Zhou, Wenyuan, Deng, Aiping, Fan, Xiaoxing, Han, Yeling, Gao, Yajun, Yuan, Lei, Zheng, Xiangfeng, Xiong, Dan, Xu, Xuechao, Zhu, Guoqiang, Yang, Zhenquan
• Format: Article
• Language: English
• Subjects: Biosensing Techniques - methods; Colorimetry - methods; Food Contamination - analysis; Food Microbiology; Limit of Detection; Staphylococcus aureus - isolation & purification; Staphylococcus Phages
• ISSN: 1095-9998

Although bacteriophage-based biosensors hold promise for detecting Staphylococcus aureus in food products in a timely, simple, and sensitive manner, the associated targeting mechanism of the biosensors remains unclear. Herein, a colourimetric biosensor SapYZU11@ZnFe O , based on a broad-spectrum S. aureus lytic phage SapYZU11 and a ZnFe O nanozyme, was constructed, and its capacity to detect viable S. aureus in food was evaluated. Characterisation of SapYZU11@ZnFe O revealed its effective immobilisation, outstanding biological activity, and peroxidase-like capability. The peroxidase activity of SapYZU11@ZnFe O significantly decreased after the addition of S. aureus, potentially due to blockage of the nanozyme active sites. Moreover, SapYZU11@ZnFe O can detect S. aureus from various sources and S. aureus isolates that phage SapYZU11 could not lyse. This may be facilitated by the adsorption of the special receptor-binding proteins on the phage tail fibre and wall teichoic acid receptors of S. aureus. Besides, SapYZU11@ZnFe O exhibited remarkable sensitivity and specificity when employing colourimetric techniques to rapidly determine viable S. aureus counts in food samples, with a detection limit of 0.87 × 10  CFU/mL. Thus, SapYZU11@ZnFe O has broad application prospects for the detection of viable S. aureus cells on food substrates.