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The underlying mechanisms and biochemical actions responsible for inactivation of pathogenic gram-positive Staphylococcus aureus (S. aureus) and gram-negative Salmonella abony (S. abony) bacteria upon exposure to sub-atmospheric plasma has been investigated. Reduction in colony forming units of the bacteria is established in 60 min and 40 min for S. aureus and S. abony respectively via 6-log reduction curves. The percentage change in reactive oxygen species, such as •OH and H2O2 formed on bacterial membrane during plasma exposure are analysed using spectroflurometer. S. aureus exhibited a significant increase of 324.23% and 1554.84% in •OH and H2O2 radicals respectively. Whereas, 98.14% and 54.49% increase in •OH and H2O2 radicals respectively was observed in S. abony. The oxidation and degradation of DNA is analysed using an ultra violet visible spectrophotometer. The leakage of proteins, lipids, and nucleic acid molecules due to plasma exposure is studied by Attenuated Total Reflectance Fourier-transform infrared spectroscopy (ATR-FTIR). The alteration of secondary protein structure on the cell membrane is observed using Circular Dichroism. Upon exposure to plasma, S. aureus shows a secondary protein structural transition from α-helix (2.4%), β-sheet (78.3%) mixture to modified β-sheet structure (0% α-helix, 79.1% β-sheet). Whereas, S.abony shows a transition from α-helix (1%), β-sheet (64.9%) mixture to modified β-sheet structure (0% α-helix, 74.5% β-sheet). The bacterial morphological study (swelling/shrinking) done using Field Emission Scanning Electron Microscopy (FE-SEM) reveals the deformation of cell membrane. Above findings pave the way for a better understanding of the processes of antimicrobial inactivation strategies when the plasma sterilization process is employed. [ABSTRACT FROM AUTHOR]

The ability to quickly and accurately analyze Staphylococcus aureus (S. aureus) and isolate the bacteria in a simplified setting is crucial for the early identification and treatment of infectious illnesses. Here, we describe the development of a new aptamer-based detection and separation technique that combines Mg2+-dependent DNAzyme amplification cascades with catalytic hairpin assembly for enhanced sensitivity. This technique uses a rolling circle amplification procedure to build a detection scaffold with a repetitive functional hairpin structure that, upon identifying S. aureus, can launch a catalytic hairpin assembly-mediated DNAzyme-based cascade signal amplification. This allows S. aureus to be isolated using low-speed centrifugation and simultaneously quantified. The approach has a low limit of detection of 21 cfu/mL and a broad detection range of six orders of magnitude due to the inclusion of the catalytic hairpin assembly for signal amplification. In addition to high sensitivity, the method also demonstrates high selectivity for the identification and isolation of S. aureus, making it a useful instrument for reporting S. aureus infections. [ABSTRACT FROM AUTHOR]

In this article, we propose a simple photochemical method to synthesize pure La2Ti2O7 films and La2Ti2O7 films doped with silver at 1.0, 3.0, and 5.0 mol%. After annealing the photo-deposited films at 900 °C, XRD, SEM, and XPS analyses showed the formation of a monoclinic La2Ti2O7 phase and the presence of Ag and AgO in doped samples. Photocatalytic tests for Congo red degradation demonstrated that pure La2Ti2O7 achieved 25.4% degradation, while doped samples reached a maximum of 92.7% degradation. Moreover, increasing silver doping on La2Ti2O7 films significantly reduced the growth of Staphylococcus aureus, indicating potential antibacterial properties. The enhanced photoactivity was attributed to the formation of a type I heterojunction between La2Ti2O7 and AgO, and a degradation mechanism was proposed based on Congo red degradation. [ABSTRACT FROM AUTHOR]

In the present work, zinc sulphide (ZnS) nanoparticles are synthesized via solvothermal route using different capping agents. The sphalerite phase is detected by X-ray diffraction (XRD) analysis. The morphology of the nanoparticles is confirmed by scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). The average particle size is found between 5 and 7 nm as calculated by HRTEM analysis. Energy dispersive X-ray spectroscopy (EDX) specified the desired elemental composition. Bandgap studies are done by UV–visible absorption and the photoluminescence spectroscopy (PL) gives the emission peaks centered at 452 nm and 460 nm. Fourier transform infra-red spectroscopy (FTIR) of ZnS nanoparticles confirmed the presence of various functional groups and showed the encapsulation of capping agents. The cylindrical non-woven network of PAN-ZnS nanofibers synthesized by electrospinning technique as confirmed by SEM and the distribution of nanoparticles in the polymer matrix is confirmed by HRTEM analysis. EDX and FTIR showed the incorporation of ZnS nanoparticles in polymer matrix. The objective of the present work is to synthesize the PAN-ZnS composite nanofibers for antibacterial applications. To the best of our knowledge this type of studies using polyacrylonitrile (PAN) as a polymer are not found in the literature showing the novelty of our work. [ABSTRACT FROM AUTHOR]

Hyper-IgE syndromes (HIES) are a group of inborn errors of immunity (IEI) caused by monogenic defects such as in the gene STAT3 (STAT3-HIES). Patients suffering from HIES show an increased susceptibility to Staphylococcus aureus (S. aureus) including skin abscesses and pulmonary infections. To assess if the underlying immune defect of STAT3-HIES patients influences the resistance patterns, pathogenicity factors or strain types of S. aureus. We characterized eleven S. aureus strains isolated from STAT3-HIES patients (n = 4) by whole genome sequencing (WGS) to determine presence of resistance and virulence genes. Additionally, we used multi-locus sequence typing (MLST) and protein A (spa) typing to classify these isolates. Bacterial isolates collected from this cohort of STAT3-HIES patients were identified as common spa types in Germany. Only one of the isolates was classified as methicillin-resistant S. aureus (MRSA). For one STAT3 patient WGS illustrated that infection and colonization occurred with different S. aureus isolates rather than one particular clone. The identified S. aureus carriage profile on a molecular level suggests that S. aureus strain type in STAT3-HIES patients is determined by local epidemiology rather than the underlying immune defect highlighting the importance of microbiological assessment prior to antibiotic treatment. [ABSTRACT FROM AUTHOR]

The rapid spread of staphylococcus aureus (S. aureus) causes an increased morbidity and mortality, as well as great economic losses in the world. Anti-S. aureus infection becomes a major challenge for clinicians and nursing professionals to address drug resistance. Hence, it is urgent to explore high efficiency, low toxicity, and environmental-friendly methods against S. aureus. Metal-organic frameworks (MOFs) represent great potential in treating S. aureus infection due to the unique features of MOFs including tunable chemical constitute, open crystalline structure, and high specific surface area. Especially, these properties endow MOF-based materials outstanding antibacterial effect, which can be mainly attributed to the continuously released active components and the exerted catalytic activity to fight bacterial infection. Herein, the structural characteristics of MOFs and evaluation method of antimicrobial activity are briefly summarized. Then we systematically give an overview on their recent progress on antibacterial mechanisms, metal ion sustained-release system, controlled delivery system, catalytic system, and energy conversion system based on MOF materials. Finally, suggestions and direction for future research to develop and mechanism understand MOF-based materials are discussed in antibacterial application. [ABSTRACT FROM AUTHOR]

Despite the growing need for effective and environmentally friendly antimicrobial agents, the synthesis methods for such materials often involve toxic chemicals and complex procedures. There is a pressing need for a sustainable approach to synthesize nanoparticles with potent antibacterial properties. This study aims to address this gap by developing a green synthesis method for silver nanoparticles (Ag NPs) using Amla extract. Powder X-ray diffraction (XRD), UV–Vis absorption spectroscopy, and Transmission Electron Microscopy (TEM) demonstrated that face-centered cubic Ag NPs with sizes in the range of 15–30 nm can be synthesized through an environmentally friendly process. Further, the formation mechanism of Ag NPs has been discussed in detail with the help of schematic diagrams. The Amla-derived Ag NPs have been further tested for their antibacterial activity against two different antibacterial strains: Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) using the plate count method. The NPs showed excellent biocompatibility where approximately 90% of growth reduction have been found for both strains at 100 μg/mL of Ag NPs and growth time of 30 min. These outcomes exhibited that Ag NPs, as a kind of antibacterial material, had an incredible guarantee for application in a wide scope of biomedical applications. [ABSTRACT FROM AUTHOR]

Here, we introduce a new technique called embedded passivated-electrode insulator-based dielectrophoresis (EπDEP) for preconcentration, separation, or enrichment of bioparticles, including living cells. This new method combines traditional electrode-based DEP and insulator-based DEP with the objective of enhancing the electric field strength and capture efficiency within the microfluidic channel while alleviating direct contact between the electrode and the fluid. The EπDEP chip contains embedded electrodes within the microfluidic channel covered by a thin passivation layer of only 4 μm. The channel was designed with two nonaligned vertical columns of insulated microposts (200 μm diameter, 50 μm spacing) located between the electrodes (600 μm wide, 600 μm horizontal spacing) to generate nonuniform electric field lines to concentrate cells while maintaining steady flow in the channel. The performance of the chip was demonstrated using Gram-negative ( Escherichia coli) and Gram-positive ( Staphylococcus aureus) bacterial pathogens in aqueous media. Trapping efficiencies of 100 % were obtained for both pathogens at an applied AC voltage of 50 V peak-to-peak and flow rates as high as 10 μl/min. [ABSTRACT FROM AUTHOR]