Label-free fiber optic optrode for the detection of class C β-lactamases expressed by drug resistant bacteria

• DOI: 10.1364/boe.8.005191
• Publication Date: 2017-10-23T17:00:54Z
• Authors: Simona Zuppolini; Giuseppe Quero; Marco Consales; Laura Diodato; Patrizio Vaiano; Alberto Venturelli; Matteo Santucci; Francesca Spyrakis; Maria P. Costi; Michele Giordano; Antonello Cutolo; Andrea Cusano; Anna Borriello
• Keywords: 0301 basic medicine; 03 medical and health sciences; Multilayers; (060.2390) Fiber optic, infrared; (170.4580) Optical diagnostics for medicine; (230.4170) Multilayers; (280.1415) Biological sensing and sensors; (350.2770) Gratings; Biotechnology; Atomic and Molecular Physics, and Optics; Biological sensing and sensors; Fiber optic; Gratings; Optical diagnostics for medicine; 3. Good health

This paper reports the experimental assessment of an automated optical assay based on label free optical fiber optrodes for the fast detection of class C β-lactamases (AmpC BLs), actually considered as one of the most important sources of resistance to β-lactams antibiotics expressed by resistant bacteria. Reflection-type long period fiber gratings (RT-LPG) have been used as highly sensitive label free optrodes, while a higher affine boronic acid-based ligand was here selected to enhance the overall assay performances compared to those obtained in our first demonstration. In order to prove the feasibility analysis towards a fully automated optical assay, an engineered system was developed to simultaneously manipulate and interrogate multiple fiber optic optrodes in the different phases of the assay. The automated system tested in AmpC solutions at increasing concentrations demonstrated a limit of detection (LOD) of 6 nM, three times better when compared with the results obtained in our previous work. Moreover, the real effectiveness of the proposed optical assay has been also confirmed in complex matrices as the case of lysates of Escherichia coli overexpressing AmpC.