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As a multidrug-resistant pathogen, Acinetobacter baumannii has long been identified as one of the most common nosocomial bacteria. High-performance recognition probes for wide-spectrum detection of A. baumannii are highly desired to achieve efficient diagnosis and timely treatment of infectious diseases induced by this pathogen. An engineering tail fiber protein (ETFP) named as Gp50 encoded by lytic phage Abp9 was expressed in Escherichia coli and identified as a binding protein for A. baumannii . According to the results of genome sequencing of an A. baumannii wild strain and phage-resistant strains, the binding receptor of ETFP Gp50 is inferred to be a lipopolysaccharide distributed on the bacterial surface. The engineering protein did not show lytic activity to A. baumannii , which facilitates the development of reliable diagnosis kits and biosensors with high flexibility and low false-negative rate. The results of specificity study show that ETFP Gp50 is a species-specific binding protein with a recognition rate of 100% for all tested 77 A. baumannii strains, while that of the natural phage Abp9 is only 27.3%. With the engineering protein, a fluorescence method was developed to detect A. baumannii with a detection range of 2.0 × 10 2 to 2.0 × 10 8 cfu mL -1 . The method has been used for the quantification of A. baumannii in a diverse sample matrix with acceptable reliability. The work demonstrates the application potential of ETFP Gp50 as an ideal recognition probe for rapid screening of A. baumannii strains in a complicated sample matrix.

As a "superbug", methicillin-resistant Staphylococcus aureus (MRSA) has long been one of the most ubiquitous drug-resistant bacteria inducing numerous nosocomial infections. To achieve effective diagnosis and following treatment decision of infectious diseases induced by MRSA, it is highly desired to establish rapid analysis and antibiotic susceptibility test methods for this pathogen. In this study, we successfully expressed a bifunctional protein by fusing green fluorescent protein and cellular wall-binding domain of bacteriophage P108. The bifunctional protein can be employed as a signal probe for broad-spectrum fluorimetry of MRSA strains because it can both bind with the target pathogen and emit intensive fluorescence. By using it as the signal probe and porcine IgG as the capture agent, MRSA can be analyzed within a dynamic range of 1.0 × 10 3 -2.0 × 10 7  CFU mL -1 with a sandwich mode. The fluorimetry was also applied to test antibiotic susceptibility of this pathogen to five antibiotics, and all results are conformable with those obtained with a standard micro broth dilution method. The above results demonstrate the attractive perspective of the bifunctional protein for rapid diagnosis and effective medication of infectious diseases induced by MRSA., (Copyright © 2022 Elsevier B.V. All rights reserved.)

As one of the most common and noticeable superbugs, methicillin-resistant Staphylococcus aureus (MRSA) has long been a major threat to public health. To meet the demand for effective diagnosis of MRSA-induced infection, it is urgent to establish rapid assay method for this type of pathogen. In this study, an aqueous soluble cellular wall-binding domain (CWBD) protein from bacteriophage P108 was obtained with a recombinant expression technique. It can act as a wide-spectrum binding agent for all MRSA strains and exclude the interference from methicillin-susceptible strains of Staphylococcus aureus and other species of bacteria. To establish a lateral flow assay (LFA) method for MRSA, CWBD-coupled time-resolved fluorescent microspheres (FMs) were used as signal probes for tracing MRSA, and a nitrocellulose membrane immobilized with porcine IgG was used to capture MRSA. With the LFA based on sandwich format, MRSA can be assayed within 10 min with a broad linear range of 6.6 × 10 2 -6.6 × 10 7  CFU/mL. Its application potential has been demonstrated by assaying different types of bacteria-contaminated real samples. The results suggest that the LFA strip using recombinant CWBD as the recognition agent provides a rapid, portable, cost-effective approach for point-of-care testing of MRSA., (Copyright © 2021 Elsevier B.V. All rights reserved.)

As new type of catalysts, dual or multiple atomic clusters have displayed extremely high atom utilization rate and superior catalytic activity. In the present work, a metal binuclear atom pair with unique cobalt coordination environment of Co 2 -O 8 were prepared on the supports of MOFs MIL-53(Al), and named as Co dual-atom clusters (CoDACs). Fascinatingly, CoDACs with desirable water dispersibility display very high catalytic efficiency for redox-based chemiluminescent (CL) reaction by generating abundant reactive oxygen species. The catalysts boosted the CL signal of luminol-H 2 O 2 system for 1192 times as their concentration were 1.0 μg mL-1, thus can be applied as superior CL probes for tracing biorecognition events. To verify their application potential, CoDACs were used to establish a CL method for analyzing methicillin-resistant Staphylococcus aureus (MRSA) strains by adopting cell wall bind domain of bacteriophage P108 as a recognizer. The method displays a dynamic range of 6.1 × 102 - 6.1 × 107 CFU mL-1 and a detection limit of 220 CFU mL-1. The results for analysis of MRSA in biological, drug and food samples manifest their reliability for real application. To our best knowledge, it is the first study focusing on DACs as efficient catalysts for CL reaction. [Display omitted] • Cobalt dual-atom clusters were prepared on the supports of MOFs MIL-53(Al). • The aqueous dispersible clusters can significantly boost chemiluminescent signal. • The clusters were used as signal probes for tracing biorecognition events. [ABSTRACT FROM AUTHOR]