Tail Fiber Protein-Immobilized Magnetic Nanoparticle-Based Affinity Approaches for Detection of Acinetobacter baumannii

Abstract

Acinetobacter baumannii (A. baumannii) strains are common nosocomial pathogens that can cause infections and can easily become resistant to antibiotics. Thus, analytical methods that can be used to rapidly identify A. baumannii from complex samples should be developed. Tail fiber proteins derived from the tail fibers of bacteriophages can recognize specific bacterial surface polysaccharides. For example, recombinant tail proteins, such as TF2 and TF6 derived from the tail fibers of bacteriophages ϕAB2 and ϕAB6, can recognize A. baumannii clinical isolates M3237 and 54149, respectively. Thus, TF2 and TF6 can be used as probes to target specific A. baumannii strains. Generally, TF2 and TF6 are tagged with a hexahistidine (His6) for ease of purification. Given that His6 possesses specific affinity toward alumina through His6–Al chelation, TF2- and TF6-immobilized alumina-coated magnetic nanoparticles (Fe3O4@Al2O3 MNPs) were generated through chelation under microwave heating (power, 900 W) for 60 s in this study. The as-prepared TF2-Fe3O4@Al2O3 and TF6-Fe3O4@Al2O3 MNPs were used as affinity probes to trap trace A. baumannii M3237 and 54149, respectively, from sample solutions. Matrix-assisted laser desorption/ionization mass spectrometry capable of identifying bacteria on the basis of the obtained fingerprint mass spectra of intact bacteria was used as the detection tool. Results demonstrated that the current approach can be used to distinguish A. baumannii M3237 from A. baumannii 54149 by using TF2-Fe3O4@Al2O3 and TF6-Fe3O4@Al2O3 MNPs as affinity probes. Furthermore, the limits of detection of the current method for A. baumannii M3237 and 54149 are ∼105 and ∼104 cells mL–1, respectively. The feasibility of using the developed method to selectively detect A. baumannii M3237 and 54149 from complex serum samples was demonstrated.

Isolation and Characterization of AbTJ, an Acinetobacter baumannii Phage, and Functional Identification of Its Receptor-Binding Modules

“…Moreover, considering that threats of A. baumannii to patients in hospitals and the complete removal of pathogens from hospitals are difficult, effective, and fast analytical methods should be developed for rapid pathogen identification, thereby enabling prompt treatment of patients [37]. Once pathogens are successfully detected and identified, precise treatment can be implemented [38].…”

“…Tail fiber proteins on the tail fibers of bacteriophages can be massively generated through genetic engineering and can be used as suitable probes to target their host bacteria. Recently, Bai et al described a method for detecting bacteria using TFPs of phages [37]. The authors used the TFPs-magnetic nanoparticles as affinity probes to trap trace A. baumannii and used matrix-assisted laser desorption/ionization mass spectrometry as the detection tool.…”

DNA based biosensing of Acinetobacter baumannii using nanoparticles aggregation method

“…Obtained results by proposed biosensor were compared with the previously reported method [ Table 1 ]. Analytical result show that the proposed biosensor has the capability of detecting A. baumannii with sensitivity and selectivity compared with previously reported studies [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ].

Figure 4 A : Fluorescence and absorbance spectrum of hybridization in various concentrations (10 −9 ,10 −12 ,10 −17 , and 10 −21 M) of Acinetobacter c DNA with pDNA B: Calibration curve (n = 3, SD = 2.06).

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Rapid and multiplex detection of nosocomial pathogens on a phage‐based magnetoresistive lab‐on‐chip platform

“…Moreover, only when the MNPs were functionalized with the respective RBP, a significant capture of the target bacterium was achieved, demonstrating the specificity of the assay and the potential of using RBPs as biorecognition probes on MNPs for bacterial labelling. Although recent studies have described the conjugation of MNPs with phage proteins (Bai et al, 2019;Denyes et al, 2017;Kretzer et al, 2018;Sumrall et al, 2020), a multiplex magnetic capture assay using two bacterial genus-specific RBPs, as herein presented, has never been reported. Moreover, while the majority of the magnetic-based techniques for the concentration of bacterial cells reported in the literature rely on antibodies, this approach presents several advantages due to the inherent properties of the RBPs (Santos et al, 2018;Singh et al, 2012), allowing to overcome the drawbacks of the immunomagnetic assays, particularly low stability, high associated costs and low specificity (Sande et al, 2020;Sharma et al, 2016;Xu et al, 2019).…”