Electrochemical-based ''antibiotsensor'' for the whole-cell detection of the vancomycin-susceptible bacteria

An electrochemical biosensor for Staphylococcus aureus detection based on a multilevel surface 3D micro/nanostructure

Detection of pathogens is one of the key concerns for hospitals, the food industry, water suppliers, or other environmental engineering practices because pathogens can cause a wide range of infectious risks. Staphylococcus aureus (S. aureus) is one of the most common pathogens that are hazardous to human health and its existence is an important index to the safety of food, environmental sanitation, or medical products. In this study, we prepared an electrode with designed surface multilevel 3D micro/nano protrusions for facile and efficient S. aureus detection. The existence of these multilevel protrusions enhanced the adsorption of S. aureus. Hence, the detection limit could be as low as 10 CFU mL-1. Furthermore, the electrode was also successfully used to detect S. aureus in actual samples, such as milk and artificial human tissue fluid. It was found that the recovery of the reported approach showed no significant difference from that of the traditional plate count method. However, compared with the plate count method, the detection process of our approach is much more time-saving and easy-operating. These advantages of the approach we report, such as high sensitivity, reliability, quickness, and user-friendliness, make it a potential platform for detecting S. aureus in relation to the food industry and clinical diagnosis.

Rapid Detection and Identification of Vancomycin-Sensitive Bacteria Using an Electrochemical Apta-Sensor

In order to combat the complex and diverse infections caused by bacteria, it is essential to develop efficient diagnostic tools. Current techniques for bacterial detection rely on laborious multistep procedures, with high costs and extended time of analysis. To overcome these limitations, we propose here a novel portable electrochemical biosensor for the rapid detection and identification of Gram-positive bacteria that leverages the recognition capabilities of vancomycin and aptamers. A vancomycin-modified screen-printed carbon electrode was used to selectively capture Gram-positive bacteria susceptible to this antibiotic. Electrochemical impedance spectroscopy and scanning electron microscopy demonstrated that capture was achieved in 10 min, with a limit of detection of only 2 CFU/mL. We then tested the device's potential for aptamer-based bacterial identification using Staphylococcus aureus and Bacillus cereus as the test strains. Specifically, electrodes with captured bacteria were exposed to species-specific aptamers, and the resulting changes in current intensity were analyzed using differential pulse voltammetry. When used directly in untreated milk or serum, the system was able to successfully identify a small amount of S. aureus and B. cereus (100 CFU/mL) in less than 45 min. This novel biosensor has the potential to serve as an invaluable tool that could be used, even by inexperienced staff, in a broad range of settings including clinical diagnostics, food safety analysis, environmental monitoring, and security applications.

Electrochemical Biosensors for the Detection of Antibiotics in Milk: Recent Trends and Future Perspectives

Antibiotics have emerged as ground-breaking medications for the treatment of infectious diseases, but due to the excessive use of antibiotics, some drugs have developed resistance to microorganisms. Because of their structural complexity, most antibiotics are excreted unchanged, polluting the water, soil, and natural resources. Additionally, food items are being polluted through the widespread use of antibiotics in animal feed. The normal concentrations of antibiotics in environmental samples typically vary from ng to g/L. Antibiotic residues in excess of these values can pose major risks the development of illnesses and infections/diseases. According to estimates, 300 million people will die prematurely in the next three decades (by 2050), and the WHO has proclaimed "antibiotic resistance" to be a severe economic and sociological hazard to public health. Several antibiotics have been recognised as possible environmental pollutants (EMA) and their detection in various matrices such as food, milk, and environmental samples is being investigated. Currently, chromatographic techniques coupled with different detectors (e.g., HPLC, LC-MS) are typically used for antibiotic analysis. Other screening methods include optical methods, ELISA, electrophoresis, biosensors, etc. To minimise the problems associated with antibiotics (i.e., the development of AMR) and the currently available analytical methods, electrochemical platforms have been investigated, and can provide a cost-effective, rapid and portable alternative. Despite the significant progress in this field, further developments are necessary to advance electrochemical sensors, e.g., through the use of multi-functional nanomaterials and advanced (bio)materials to ensure efficient detection, sensitivity, portability, and reliability. This review summarises the use of electrochemical biosensors for the detection of antibiotics in milk/milk products and presents a brief introduction to antibiotics and AMR followed by developments in the field of electrochemical biosensors based on (i) immunosensor, (ii) aptamer (iii) MIP, (iv) enzyme, (v) whole-cell and (vi) direct electrochemical approaches. The role of nanomaterials and sensor fabrication is discussed wherever necessary. Finally, the review discusses the challenges encountered and future perspectives. This review can serve as an insightful source of information, enhancing the awareness of the role of electrochemical biosensors in providing information for the preservation of the health of the public, of animals, and of our environment, globally.

Antibiotic resistance mechanism and diagnosis of common foodborne pathogens based on genotypic and phenotypic biomarkers

The emergence of antibiotic-resistant bacteria due to the overuse or inappropriate use of antibiotics has become a significant public health concern. The agri-food chain, which serves as a vital link between the environment, food, and human, contributes to the large-scale dissemination of antibiotic resistance, posing a concern to both food safety and human health. Identification and evaluation of antibiotic resistance of foodborne bacteria is a crucial priority to avoid antibiotic abuse and ensure food safety. However, the conventional approach for detecting antibiotic resistance heavily relies on culture-based methods, which are laborious and time-consuming. Therefore, there is an urgent need to develop accurate and rapid tools for diagnosing antibiotic resistance in foodborne pathogens. This review aims to provide an overview of the mechanisms of antibiotic resistance at both phenotypic and genetic levels, with a focus on identifying potential biomarkers for diagnosing antibiotic resistance in foodborne pathogens. Furthermore, an overview of advances in the strategies based on the potential biomarkers (antibiotic resistance genes, antibiotic resistance-associated mutations, antibiotic resistance phenotypes) for antibiotic resistance analysis of foodborne pathogens is systematically exhibited. This work aims to provide guidance for the advancement of efficient and accurate diagnostic techniques for antibiotic resistance analysis in the food industry.

Recent advances in gold electrode fabrication for low-resource setting biosensing

Gold electrodes are some of the most prevalent electrochemical biosensor substrate materials because they are readily functionalized with thiolated biomolecules. Yet, conventional methods to fabricate gold electrodes are costly and require onerous equipment, precluding them from implementation in low-resource settings (LRS). Recently, a number of alternative gold electrode fabrication methods have been developed to simplify and lower the cost of manufacturing. These methods include screen and inkjet printing as well as physical fabrication with common materials such as wire or gold leaf. All electrodes generated with these methods have successfully been functionalized with thiolated molecules, demonstrating their suitability for use in biosensors. Here, we detail recent advances in the fabrication, characterization and functionalization of these next-generation gold electrodes, with an emphasis on comparisons between cost and complexity with traditional cleanroom fabrication. We highlight gold leaf electrodes for their potential in LRS. This class of electrodes is anticipated to be broadly applicable beyond LRS due to their numerous inherent advantages.

A Review of Detection Methods for Vancomycin-Resistant Enterococci (VRE) Genes: From Conventional Approaches to Potentially Electrochemical DNA Biosensors

Vancomycin-resistant Enterococci (VRE) genes are bacteria strains generated from Gram-positive bacteria and resistant to one of the glycopeptides antibiotics, commonly, vancomycin. VRE genes have been identified worldwide and exhibit considerable phenotypic and genotypic variations. There are six identified phenotypes of vancomycin-resistant genes: VanA, VanB, VanC, VanD, VanE, and VanG. The VanA and VanB strains are often found in the clinical laboratory because they are very resistant to vancomycin. VanA bacteria can pose significant issues for hospitalized patients due to their ability to spread to other Gram-positive infections, which changes their genetic material to increase their resistance to the antibiotics used during treatment. This review summarizes the established methods for detecting VRE strains utilizing traditional, immunoassay, and molecular approaches and then focuses on potential electrochemical DNA biosensors to be developed. However, from the literature search, no information was reported on developing electrochemical biosensors for detecting VRE genes; only the electrochemical detection of vancomycin-susceptible bacteria was reported. Thus, strategies to create robust, selective, and miniaturized electrochemical DNA biosensor platforms to detect VRE genes are also discussed.

Recent Developments in Electrochemical Sensors for the Detection of Antibiotic-Resistant Bacteria

The development of efficient point-of-care (POC) diagnostic tools for detecting infectious diseases caused by destructive pathogens plays an important role in clinical and environmental monitoring. Nevertheless, evolving complex and inconsistent antibiotic-resistant species mire their drug efficacy. In this regard, substantial effort has been expended to develop electrochemical sensors, which have gained significant interest for advancing POC testing with rapid and accurate detection of resistant bacteria at a low cost compared to conventional phenotype methods. This review concentrates on the recent developments in electrochemical sensing techniques that have been applied to assess the diverse latent antibiotic resistances of pathogenic bacteria. It deliberates the prominence of biorecognition probes and tailor-made nanomaterials used in electrochemical antibiotic susceptibility testing (AST). In addition, the bimodal functional efficacy of nanomaterials that can serve as potential transducer electrodes and the antimicrobial agent was investigated to meet the current requirements in designing sensor module development. In the final section, we discuss the challenges with contemporary AST sensor techniques and extend the key ideas to meet the demands of the next POC electrochemical sensors and antibiotic design modules in the healthcare sector.

Recent advances in the biosensors application for the detection of bacteria and viruses in wastewater

The presence of disease-causing pathogens in wastewater can provide an excellent diagnostic tool for infectious diseases. Biosensors are far superior to conventional methods used for regular infection screening and surveillance testing. They are rapid, sensitive, inexpensive portable and carry no risk of exposure in their detection schemes. In this context, this review summarizes the most recently developed biosensors for the detection of bacteria and viruses in wastewater. The review also provides information on the new detection methods aimed at screening for SARS-CoV-2, which has now caused more than 4 million deaths. In addition, the review highlights the potential behind on-line and real-time detection of pathogens in wastewater pipelines. Most of the biosensors reported were not targeted to wastewater samples due to the complexity of the matrix. However, this review highlights on the performance factors of recently developed biosensors and discusses the importance of nanotechnology in amplifying the output signals, which in turn increases the accuracy and reliability of biosensors. Current research on the applicability of biosensors in wastewater promises a dramatic change to the conventional approach in the field of medical screening.

Electrochemical Sensors for Antibiotic Susceptibility Testing: Strategies and Applications

Increasing awareness of the impacts of infectious diseases has driven the development of advanced techniques for detecting pathogens in clinical and environmental settings. However, this process is hindered by the complexity and variability inherent in antibiotic-resistant species. A great deal of effort has been put into the development of antibiotic-resistance/susceptibility testing (AST) sensors and systems to administer proper drugs for patient-tailored therapy. Electrochemical sensors have garnered increasing attention due to their powerful potential to allow rapid, sensitive, and real-time monitoring, alongside the low-cost production, feasibility of minimization, and easy integration with other techniques. This review focuses on the recent advances in electrochemical sensing strategies that have been used to determine the level of antibiotic resistance/susceptibility of pathogenic bacteria. The recent examples of the current electrochemical AST sensors discussed here are classified into four categories according to what is detected and quantitated: the presence of antibiotic-resistant genes, changes in impedance caused by cell lysis, current response caused by changes in cellular membrane properties, and changes in the redox state of redox molecules. It also discusses potential strategies for the development of electrochemical AST sensors, with the goal of broadening their practical applications across various scientific and technological fields.