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Hydrogel-based wound management systems represent a promising avenue in tissue engineering for restoring and preserving the normal functionality of damaged tissues. Incorporating active components into hydrogel matrices enhances their suitability for biomedical applications. In this study, we investigated the integration of l -proline, a nonessential imino acid with largely unexplored roles in living systems, into alginate dialdehyde-gelatin hydrogel for wound healing purposes. Physicochemical properties of the resulting hydrogel film, termed ADAGLP, were meticulously evaluated, including wound healing efficacy in vitro and anti-biofilm activity against Gram-positive and Gram-negative microorganisms. Fourier-transform infrared spectroscopy (FTIR) analysis provided insights into the interaction between l -proline and ADAG. Films incorporating 0.5% l -proline were selected for comprehensive investigation. Comparative analysis revealed prolonged gelation time and increased water holding capacity of ADAGLP compared to ADAG films. Moreover, ADAGLP exhibited a significantly higher degradation rate (69.5 ± 3.2%) compared to ADAG (35.2 ± 1.6%). Remarkably, ADAGLP demonstrated cyto-compatibility, non-toxicity, and facilitated migration to the scratch area in vitro conditions. Notably, it exhibited potent anti-biofilm properties. Our findings suggest that ADAGLP hydrogel holds promise as a biomaterial for wound care, offering prolonged drug delivery and maintaining optimal moisture levels in wound areas. The incorporation of l -proline in the wound microenvironment may contribute to enhanced tissue remodeling, by inhibiting biofilm formation, further highlighting the potential of this hydrogel system in wound healing applications. [ABSTRACT FROM AUTHOR]

Biofilms are a severe problem for public health because of the contributing recurrence of infections. Therefore, combating biofilms is a critical issue. In our study, we loaded zinc oxide (ZnO), zinc oxide borax (ZnOBorax), zinc copper oxide (ZnCuO2) nanoparticles and borax into bacterial cellulose (BC) to impart anti-biofilm and wound healing activity. The prepared BC loaded with nanoparticles (BC–NPs) was analysed via scanning electron microscopy. The nanoparticles' geometric structure and placement in BC fibres were observed. We evaluated the biofilm inhibition and biofilm degradation activities of the BC–NPs against some pathogens via a crystal violet (CV) assay and XTT (2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2 H-tetrazolium-5-carboxanilide) reduction assay. The effects of BC–NPs on cell proliferation and wound-healing ability were analysed in L929 cell line. BC–NPs exhibited better biofilm degradation activity than biofilm inhibition activity. According to the results of the CV assay, BC–ZnONPs, BC–Borax and BC–ZnOBoraxNPs inhibited 65.53%, 71.74% and 66.60% of biofilm formation of Staphylococcus aureus, respectively. BC–ZnCuO2NPs showed the most degradation activity on Pseudomonas aeruginosa and Listeria innocua biofilms. The XTT reduction assay results indicated a considerable reduction in the metabolic activity of the biofilms. Moreover, compared to the control group, BC loaded with borax and ZnO nanoparticle promoted cell migration without cytotoxicity. [ABSTRACT FROM AUTHOR]

The emergence of Multidrug-resistant (MDR) bacteria are becoming a major worldwide health concern, encouraging the development effective alternatives to conventional antibiotics. The study identified P. aeruginosa and assessed its antimicrobial sensitivity using the Vitek-2 system. Carbapenem-resistant genes were detected through Polymerase chain reaction (PCR). MDR- P. aeruginosa isolates were used to biosynthesize titanium dioxide nanoparticles (TiO2NPs) and characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM). A study involving 78 P. aeruginosa isolates revealed that 85.8% were MDR, with meropenem and amikacin showing effectiveness against 70% of the isolates. The most prevalent carbapenemase gene was blaOXA-48, present in 83% of the isolates. Majority of the isolates formed biofilms, and biosynthesized TiO2NPs were able to reduce biofilm formation by 94%. TiO2NPs exhibited potent antibacterial action against MDR-Gram-negative bacilli pathogens and showed synergistic activity with antibiotics, particularly piperacillin, with a significant fold increase in areas (283%). A new local strain of P. aeruginosa, identified as ON678251 in the World GenBank, was found capable of producing TiO2NPs. Our findings demonstrate the potential of biosynthesized TiO2NPs to manage antibiotic resistance and regulate the formation of biofilms. This presents a promising direction for the creation of novel antimicrobial agents or substitutes for use in clinical settings, particularly in the management of isolates capable of resisting multiple drugs. [ABSTRACT FROM AUTHOR]

Background: Human breast milk is a valuable source of potential probiotic candidates. The bacteria isolated from human breast milk play an important role in the development of the infant gut microbiota, exhibiting diverse biological functions. Methods: In this study, Limosilactobacillus reuteri MBHC 10138 isolated from breast milk was characterized in terms of its probiotic safety characteristics and potential efficacy in hyperuricemia, obesity, lipid liver, and dental caries, conditions which Korean consumers seek to manage using probiotics. Results: Strain MBHC 10138 demonstrated a lack of D-lactate and biogenic amine production as well as a lack of bile salt deconjugation and hemolytic activity. It also exhibited susceptibility to common antibiotics, tolerance to simulated oral–gastric–intestinal conditions, and superior biological activity compared to three L. reuteri reference strains, including KACC 11452 and MJ-1, isolated from feces, and a commercial strain isolated from human breast milk. Notably, L. reuteri MBHC 10138 showed high capabilities in assimilating guanosine (69.48%), inosine (81.92%), and adenosine (95.8%), strongly inhibited 92.74% of biofilm formation by Streptococcus mutans, and reduced lipid accumulation by 32% in HepG2 cells. Conclusions: These findings suggest that strain MBHC 10138, isolated from human breast milk, has potential to be developed as a probiotic for managing hyperuricemia, obesity, and dental caries after appropriate in vivo studies. [ABSTRACT FROM AUTHOR]

Bacteria have evolved and continue to change in response to environmental stressors including antibiotics. Antibiotic resistance and the ability to form biofilms are inextricably linked, requiring the continuous search for alternative compounds to antibiotics that affect biofilm formation. One of the latest drug classes is boron-containing compounds. Over the last several decades, boron has emerged as a prominent element in the field of medicinal chemistry, which has led to an increasing number of boron-containing compounds being considered as potential drugs. The focus of this review is on the developments in boron-containing organic compounds (BOCs) as antimicrobial/anti-biofilm probes and agents. [ABSTRACT FROM AUTHOR]

The use of nanoparticles as drug‐carrying systems in medicine has received much attention, and on the other hand, the use of plants with medicinal properties has advantages over synthetic drugs. This study aims to improve the antibacterial and anti‐biofilm properties of Euphorbia hebecarpa plant extract using chitosan nanoparticles. Extraction were performed using the modified maceration and methanol solvent. The agar disc diffusion method was carried out to investigate the antimicrobial effects and MIC at an optical density (OD) of 630 nm. The anti‐biofilm agent's influence was measured at OD 570 nm, and the metabolic activity of bacteria in the damaged biofilm was determined using triphenyl tetrazolium chloride (TTC) staining. The nanoparticles were obtained by following the ionic gelation method and its characteristics were evaluated. Chitosan nanoparticles loaded with plant extract were found to be spherical shape with hydrodynamic diameter of 142 nm, a polydispersity index (PDI) of 0.184, a zeta potential of +28.6 mV. It was determined that the loading capacity (% LC) and encapsulation efficiency (% EE) percentages were 33% and 40%, respectively. The diameter of the inhibition zone in the agar disc diffusion test for both bacteria using nanoparticles loaded with the extract increased compared with control groups. Also, at a concentration of 4 mg/mL of loaded nanoparticles, 49.33% of Escherichia coli biofilm and 62.7% of Staphylococcus aureus biofilm were destroyed. The data obtained from the tests performed in this study show that the use of Euphorbia plant extract in the form of chitosan nanoparticles can have more antimicrobial and anti‐biofilm effects. [ABSTRACT FROM AUTHOR]

The present study aimed to characterize the biosurfactants synthesized by lactic acid bacteria (LAB) obtained from fermented foods, optimize the conditions for increasing the yield of biosurfactants and explore their antimicrobial and antibiofilm potential. Out of the 26 LAB isolates, isolate BS2 showed the highest biosurfactant production as indicated in the oil displacement test, drop collapse and emulsification activity. BS2 was identified as Lactiplantibacillus plantarum 1625 using 16S-rRNA gene sequencing and phylogenetic analysis. The biosurfactant produced by BS2 was identified as an anionic glycol-lipo-proteins by employing Fourier Transform Infrared Spectroscopy (FTIR) and Gas Chromatography-Mass Spectrometry (GC-MS) analysis. The biosurfactants produced by L. plantarum 1625 demonstrated strong antibacterial and antibiofilm characteristics against pathogenic strains such as Staphylococcus aureus MTCC 1049, Escherichia coli MTCC 1587, and Pseudomonas putida MTCC 1655. The minimal inhibition concentration value of antibacterial activity was found to be 0.1 mg/mL with the inhibition percentage ranging from 90 to 95%. Further, the effect of temperature, pH, and substrate composition on biosurfactant production was also studied to enhance it production using the Box-Behnken Design approach of Response surface methodology (RSM). Application of biosurfactant led to a considerable decrease in biofilm-forming harmful bacteria, as proven by scanning electron microscopy analysis. The results highlight the potential uses of biosurfactants in distinct industries, and biotechnological contexts, especially in the creation of new antimicrobial and antibiofilm agents. [ABSTRACT FROM AUTHOR]

Long-term antibiotic treatment results in the increasing resistance of bacteria to antimicrobials drugs, so it is necessary to search for effective alternatives to prevent and treat pathogens that cause diseases. This study is aimed for biological synthesis of silver Carthamus nanoparticles (Ag-Carth-NPs) to combat microbial biofilm formation and Pseudomonas aeruginosa virulence genes. Ag-Carth-NPs are synthesized using Carthamus tenuis aqueous extract as environmentally friendly method has no harmful effect on environment. General factorial design is used to optimize Ag-Carth-NPs synthesis using three variables in three levels are Carthamus extract concentration, silver nitrate concentration and gamma radiation doses. Analysis of response data indicates gamma radiation has a significant effect on Ag-Carth-NPs production. Ag-Carth-NPs have sharp peak at λ max 425 nm, small and spherical particles with size 20.0 ± 1.22 nm, high stability up to 240 day with zeta potential around − 43 ± 0.12 mV, face centered cubic crystalline structure and FT-IR spectroscopy shows peak around 620 cm−1 that corresponding to AgNPs that stabilized by C. tenuis extract functional moiety. The antibacterial activity of Ag-Carth-NPs against pathogenic bacteria and fungi was determined using well diffusion method. The MIC values of Ag-Carth-NPs were (6.25, 6.25, 3.126, 25, 12.5, 12.5, 25 and 12.5 µg/ml), MBC values were (12.5, 12.5, 6.25, 50, 25, 25, 50 and 25 µg/ml) and biofilm inhibition% were (62.12, 68.25, 90.12, 69.51, 70.61, 71.12, 75.51 and 77.71%) against Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis, Candida tropicalis and Candida albicans respectively. Ag-Carth-NPs has bactericidal efficacy and significantly reduced the swarming, swimming motility, pyocyanin and protease production of P. aeruginosa. Furthermore, P. aeruginosa ToxA gene expression was significantly down regulated by 81.5%, while exoU reduced by 78.1%, where lasR gene expression reduction was 68%, while the reduction in exoU was 66% and 60.1% decrease in lasB gene expression after treatment with Ag-Carth-NPs. This activity is attributed to effect of Ag-Carth-NPs on cell membrane integrity, down regulation of virulence gene expression, and induction of general and oxidative stress in P. aeruginosa. Ag-Carth-NPs have no significant cytotoxic effects on normal human cell (Hfb4) but have IC50 at 5.6µg/mL against of HepG-2 cells. Limitations of the study include studies with low risks of silver nanoparticles for in vitro antimicrobial effects and its toxicity. [ABSTRACT FROM AUTHOR]

Twenty-six lactic acid bacteria were obtained from poultry feces sampled located in the Ankara area (Türkiye) and belong to the Lactobacillus genus according to the results obtained by biochemical methods. This study screened these isolates for exopolysaccharides (EPS) production. EPS production was detected in these isolates, varying from 8 mg L-1 to 353 mg L-1. The highest EPS-producing isolate (KC27L) was selected for further studies. The isolate was identified as Ligilactobacillus salivarius by 16S rRNA analysis. Furthermore, the anti-biofilm and antioxidant abilities of the cell-free supernatant (CFSKC27L) and different concentrations (0.5 mg L-1 and 1 mg L-1) of EPS belonging to the KC27L strain (EPSKC27L) that exhibited high EPS production were determined. CFSKC27 and different concentrations (0.5 mg L-1 and 1 mg mL-1) of EPSKC27L determined the anti-biofilm impact on Escherichia coli ATCC 11229, Enterococcus faecalis ATCC 29212, and Staphylococcus aureus EB-1. The highest anti-biofilm effect in 1 mg mL-1 EPSKC27L was detected at E. coli ATCC 11229 with 87 % inhibition. Three different methods (1.1-Diphenyl-2-picrylhydrazyl radical (DPPH) removal impact, Fe2+ ion chelating and superoxide anion radical scavenging activity) designated antioxidant activity. The highest 1.1-Diphenyl-2-picrylhydrazyl radical (DPPH) removal impact, Fe2+ ion chelating, and superoxide anion radical scavenging activity were found in 1 mg mL-1 EPSKC27L (79.6%, 24.9%, and 61.6%, respectively). Both anti-biofilm and antioxidant activities of 1 mg mL-1 EPSKC27L were higher than postbiotic. Finally, its molecular characterization was done following the partial purification of the EPSKC27L. The EPSKC27L has two fractions with molecular weights of 1.6x10³ and 6.4 x104 Da. Monosaccharide components of EPSKC27L were found to be glucose (53.1%), fructose (18.5%), arabinose (14.6%) and mannose (13.8%). CFSKC27L and EPSKC27L obtained from L. salivarius can be antioxidants and anti-biofilm agents. [ABSTRACT FROM AUTHOR]

Chronic infections often involve notorious pathogens like Pseudomonas aeruginosa and Staphylococcus aureus, demanding innovative antimicrobial strategies due to escalating resistance. This investigation scrutinized the antibacterial prowess of bile salts, notably taurocholic acid (TCA), ursodeoxycholic acid (UDCA), and ox bile salt (OBS), against these pathogens. Evaluations encompassed minimum inhibitory concentration (MIC) determination, scrutiny of their impact on biofilm formation, and anti-virulence mechanisms. UDCA exhibited the highest efficacy, suppressing S. aureus and P. aeruginosa biofilms by 83.5% and 78%, respectively, at peak concentration. TCA also significantly reduced biofilm development by 81% for S. aureus and 75% for P. aeruginosa. Microscopic analysis revealed substantial disruption of biofilm architecture by UDCA and TCA. Conversely, OBS demonstrated ineffectiveness against both pathogens. Mechanistic assays elucidated UDCA and TCA's detrimental impact on the cell membrane, prompting the release of macromolecular compounds. Additionally, UDCA and TCA inhibited protease and elastase synthesis in P. aeruginosa and staphyloxanthin and lipase production in S. aureus. These results underscore the potential of UDCA and TCA in impeding biofilm formation and mitigating the pathogenicity of S. aureus and P. aeruginosa. [ABSTRACT FROM AUTHOR]

Periodontitis is a chronic inflammatory disease resulting from the dysbiosis of periodontal bacteria and the host's immune response, leading to tissue degradation and sustained inflammation. Traditional treatments, such as mechanical debridement and antimicrobial agents, often fail to fully eradicate pathogenic bacteria, especially in deep periodontal pockets. Consequently, the need for novel therapeutic approaches has increased the interest in bioactive natural extracts, such as that of Opuntia ficus-indica, known for its anti-inflammatory, antioxidant, and antimicrobial properties. This study investigates the encapsulation of Opuntia ficus-indica extract in OFI-loaded chitosan nanoparticles (OFI-NPs) via ionotropic gelation using a microfluidic system, allowing precise control over nanoparticle characteristics and enhancing protection against enzymatic degradation. To achieve localized and sustained release in periodontal pockets, a thermo-responsive hydrogel comprising hyaluronic acid and Pluronic F127 (OFI@tgels) was developed. The transition of OFI@tgels from a solution at low temperatures to a solid at body temperature enables prolonged drug release at inflammation sites. The in vitro application of the optimized formulation eradicated biofilms of S. mutans, P. aeruginosa (PAO1), and P. gingivalis over 36 h and disrupted extracellular polymeric substance formation. Additionally, OFI@tgel modulated immune responses by inhibiting M1 macrophage polarization and promoting a shift to the M2 phenotype. These findings suggest that OFI@tgel is a promising alternative treatment for periodontitis, effectively reducing biofilm formation and modulating the immune response. [ABSTRACT FROM AUTHOR]

Shigella flexneri is a gram-negative bacterium responsible for shigellosis and bacterial dysentery. Despite using various synthetic antimicrobial agents and antibiotics, their efficacy is limited, prompting concerns over antibiotic resistance and associated health risks. This study investigated eugenol, a polyphenol with inherent antioxidant and antibacterial properties, as a potential alternative treatment. We aimed to evaluate eugenol’s antibacterial effects and mechanisms of action against S. flexneri and its impact on biofilm formation. We observed significant growth suppression of S. flexneri with eugenol concentrations of 8–10 mM (98.29%). Quantitative analysis using the Crystal Violet assay demonstrated a marked reduction in biofilm formation at 10 mM (97.01 %). Assessment of Cell Viability and morphology via Fluorescence-Activated Cell Sorting and Scanning Electron Microscopy confirmed these findings. Additionally, qPCR analysis revealed the downregulation of key genes responsible for adhesion (yebL), quorum sensing (rcsC, sdiA), and EPS production (s0482) associated with bacterial growth and biofilm formation. The present study suggests eugenol could offer a promising alternative to conventional antibiotics for treating shigellosis caused by S. flexneri. [ABSTRACT FROM AUTHOR]

Objective: The objective was to determine the in vitro antibacterial effect of the Oregano essential oil (OEO) on Streptococcus mutans (S mutans) and to explore the anti-biofilm effect and mechanism of OEO. Methods: The in vitro antibacterial susceptibility of OEO was detected by the growth curve and colony-forming unit (CFU) counting method. Confocal laser scanning microscope (CLSM) and crystal violet assay were used to explore the anti-biofilm activity of OEO, and the anti-biofilm mechanism was explored from the aspects of extracellular polysaccharides (EPS) synthesis, acidoid, and extracellular DNA changes. OEO was characterized using a gas chromatography-mass spectrometer and cytotoxicity was tested using a cell counting Kit-8 assay. Results: The minimum inhibitory concentration of OEO was 0.25 mg/mL, and the CFU showed the ability of OEO to kill planktonic bacteria. Scanning electron microscopy and CLSM showed that OEO could hinder the development of biofilms, harm bacteria, and eliminate mature biofilms by changing EPS synthesis and pH value. Carvacrol in OEO played a major role in biological antibacterial activity. OEO had low cytotoxicity and good biocompatibility. Conclusions: OEO had excellent antibacterial and anti-biofilm effects on the key virulence traits of S mutans, indicating potential prospects in preventing dental caries. [ABSTRACT FROM AUTHOR]

Abstract Staphylococcus aureus produces a plethora of virulence factors to invade and establish infections in the host system, and biofilms are more resistant to antibiotics than planktonic cells. In this study, we aimed to investigate the anti-virulence and anti-biofilm potentials of zinc sulfate against S. aureus isolates. The synergistic effect of zinc sulfate in combination with antibiotics on S. aureus was characterized using the checkerboard method. The influence of zinc sulfate on biofilm formation and virulence factors production by S. aureus was experimentally assessed. RT-qPCR was used to investigate the effect of zinc sulfate on the expression of biofilm-related genes. Zinc sulfate exhibited good antibacterial activity against S. aureus with a MIC of 128 µg/ml against all tested isolates. Also, the findings indicate a synergistic effect of a combination of zinc sulfate and antibiotics against the tested isolates. Zinc sulfate at 256 µg/ml concentration inhibited biofilm formation for all isolates. The expression of biofilm-related genes was significantly repressed in zinc sulfate-treated bacteria compared to untreated cells. Zinc sulfate could inhibit the hemolytic ability of S. aureus. Moreover, zinc sulfate-treated bacteria exhibited a significant decrease in coagulase and catalase activity relative to control untreated S. aureus. Our results support that zinc sulfate is a potential antimicrobial and anti-virulence agent against S. aureus infections.

Abstract The emergence of Multidrug-resistant (MDR) bacteria are becoming a major worldwide health concern, encouraging the development effective alternatives to conventional antibiotics. The study identified P. aeruginosa and assessed its antimicrobial sensitivity using the Vitek-2 system. Carbapenem-resistant genes were detected through Polymerase chain reaction (PCR). MDR- P. aeruginosa isolates were used to biosynthesize titanium dioxide nanoparticles (TiO2NPs) and characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM). A study involving 78 P. aeruginosa isolates revealed that 85.8% were MDR, with meropenem and amikacin showing effectiveness against 70% of the isolates. The most prevalent carbapenemase gene was bla OXA-48 , present in 83% of the isolates. Majority of the isolates formed biofilms, and biosynthesized TiO2NPs were able to reduce biofilm formation by 94%. TiO2NPs exhibited potent antibacterial action against MDR-Gram-negative bacilli pathogens and showed synergistic activity with antibiotics, particularly piperacillin, with a significant fold increase in areas (283%). A new local strain of P. aeruginosa, identified as ON678251 in the World GenBank, was found capable of producing TiO2NPs. Our findings demonstrate the potential of biosynthesized TiO2NPs to manage antibiotic resistance and regulate the formation of biofilms. This presents a promising direction for the creation of novel antimicrobial agents or substitutes for use in clinical settings, particularly in the management of isolates capable of resisting multiple drugs.

Abstract Long-term antibiotic treatment results in the increasing resistance of bacteria to antimicrobials drugs, so it is necessary to search for effective alternatives to prevent and treat pathogens that cause diseases. This study is aimed for biological synthesis of silver Carthamus nanoparticles (Ag-Carth-NPs) to combat microbial biofilm formation and Pseudomonas aeruginosa virulence genes. Ag-Carth-NPs are synthesized using Carthamus tenuis aqueous extract as environmentally friendly method has no harmful effect on environment. General factorial design is used to optimize Ag-Carth-NPs synthesis using three variables in three levels are Carthamus extract concentration, silver nitrate concentration and gamma radiation doses. Analysis of response data indicates gamma radiation has a significant effect on Ag-Carth-NPs production. Ag-Carth-NPs have sharp peak at λ max 425 nm, small and spherical particles with size 20.0 ± 1.22 nm, high stability up to 240 day with zeta potential around − 43 ± 0.12 mV, face centered cubic crystalline structure and FT-IR spectroscopy shows peak around 620 cm−1 that corresponding to AgNPs that stabilized by C. tenuis extract functional moiety. The antibacterial activity of Ag-Carth-NPs against pathogenic bacteria and fungi was determined using well diffusion method. The MIC values of Ag-Carth-NPs were (6.25, 6.25, 3.126, 25, 12.5, 12.5, 25 and 12.5 µg/ml), MBC values were (12.5, 12.5, 6.25, 50, 25, 25, 50 and 25 µg/ml) and biofilm inhibition% were (62.12, 68.25, 90.12, 69.51, 70.61, 71.12, 75.51 and 77.71%) against Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis, Candida tropicalis and Candida albicans respectively. Ag-Carth-NPs has bactericidal efficacy and significantly reduced the swarming, swimming motility, pyocyanin and protease production of P. aeruginosa. Furthermore, P. aeruginosa ToxA gene expression was significantly down regulated by 81.5%, while exoU reduced by 78.1%, where lasR gene expression reduction was 68%, while the reduction in exoU was 66% and 60.1% decrease in lasB gene expression after treatment with Ag-Carth-NPs. This activity is attributed to effect of Ag-Carth-NPs on cell membrane integrity, down regulation of virulence gene expression, and induction of general and oxidative stress in P. aeruginosa. Ag-Carth-NPs have no significant cytotoxic effects on normal human cell (Hfb4) but have IC50 at 5.6µg/mL against of HepG-2 cells. Limitations of the study include studies with low risks of silver nanoparticles for in vitro antimicrobial effects and its toxicity.

Metal-phenolic networks (MPNs)-crosslinked hyaluronic acid (HA) nanogels are fabricated for co-delivery of Fe2+ and dihydroartemisinin (DHA), enabling photothermal/DHA dually-enhanced chemodynamic therapy for treating biofilm-associated infections. [Display omitted] Chemodynamic therapy (CDT) is emerging as a promising treatment for biofilm infections. However, its effectiveness is significantly hindered by several factors: the body's stable temperature, a limited supply of Fe2+ ions, and inadequate endogenous levels of H 2 O 2 at the infection sites. Herin, our study introduces MPN-crosslinked hyaluronic acid (HA) nanogels as an effective strategy for treating biofilm-associated infections. The DHA@HA-TA/Fe (DHTF) nanogel is synthesized through the coordination reaction between Fe2+ ions and tannic acid (TA)-modified HA, with dihydroartemisinin (DHA) encapsulated within the structure. DHTF exhibits pH-/hyaluronidase-responsiveness in the biofilm infection microenvironment, enabling sustained release of DHA as a substitute for H 2 O 2 and Fe2+ for CDT. The incorporation of Fe2+/TA-based MPN and DHA within the nanogels enables photothermal/DHA dually-enhanced CDT, facilitating efficient disruption of biofilm matrices and bacterial eradication through boosting reactive oxygen species production. In vivo studies demonstrate that DHTF exhibit prolonged retention within biofilms. This ensures a sustained release of therapeutic agents and continuous anti-biofilm activity. Eventually, both in vitro and in vivo evaluations consistently confirm the significant anti-biofilm capacity of DHTF. Our findings highlight the potential of DHTF as a promising nanomedicine for biofilm-related infections, offering efficient treatment strategies that could improve clinical management of these challenging conditions. [ABSTRACT FROM AUTHOR]

Cotton gauze (CG) is the most commonly used primary wound dressing to protect wounds from the external environment. However, it is highly susceptible to fouling due to the adhesion of bacteria present on the wound surface. Bacterial colonization of the dressing is detrimental as it aids in wound infection and delays wound healing. To mitigate this issue, the objective of this study was to transform the inert CG into a fouling-resistant wound dressing that can actively resist bacterial adhesion and also prevent biofilm formation on the surface of cotton. In this work, a facile method of modifying commercial CG using oxidized dextran (Odex) was developed. Odex was derived from dextran via periodate oxidation reaction and then coated over the CG using mussel-inspired chemistry. The resultant Odex-modified CG demonstrated a substantial reduction in bacterial adhesion after 4 h of incubation in bacterial suspension. The modified gauze suppressed biofilm formation, achieving ~83% reduction in viable bacterial count as compared to unmodified CG after 48 h of incubation in the bacterial suspension. In addition, the modified CG also showed good breathability, wettability and moisture retention properties. The results suggest a promising approach of transforming inert CG into a potential fouling-resistant wound dressing for the management of wound infections. [ABSTRACT FROM AUTHOR]

Tuberculosis (TB) continues to be a primary worldwide health concern due to relatively ineffective treatments. The prolonged duration of conventional antibiotic therapy warrants innovative approaches to shorten treatment courses. In response to challenges, the study explores potential of Ajoene, a naturally occurring garlic extract-derived compound, for potential TB treatment. Mycobacterium smegmatis as a model organism for M. tuberculosis (M. tb) to investigate Ajoene's efficiency. In vitro techniques like antimicrobial susceptibility, antibiofilm, EtBr accumulation assay, and ROS assay evaluate the potency of Ajoene and conventional TB drugs against Mycobacterium smegmatis. An in-silico study also investigated the interaction between Ajoene and quorum-sensing proteins, specifically regX3, MSMEG_5244, and MSMEG_3944, which are involved in biofilm formation and sliding activity. In vitro findings revealed that Ajoene exhibited significant antibacterial activity by inhibiting growth and showing bactericidal effects. It also demonstrated additive interactions with common antibiotics such as Isoniazid and Rifampicin. Furthermore, Ajoene demonstrated a comparative interaction with commonly used antibiotics, such as Isoniazid and Rifampicin, and reduced M. smegmatis motility, both alone and in combination with these antibiotics. In silico analysis shows that Ajoene exhibited a higher binding affinity with regX3, a protein orthologous to the regX3 gene in M.tb. Ajoene also demonstrated consistent antibiofilm effects, particularly when combined synergistically with Isoniazid and Rifampicin. Mechanistic investigations demonstrated Ajoene's potential to inhibit efflux pumps and promote ROS generation in bacteria, suggesting a potential direct killing mechanism. Collectively, the findings emphasize Ajoene's effectiveness as a novel antimycobacterial and antibiofilm molecule for TB treatment. [ABSTRACT FROM AUTHOR]

Mastitis in cows is one of the most important diseases that give rise to economic losses in dairy farms. Increasing antimicrobial resistance in Staphylococcus aureus, one of the most common causes of mastitis, is a significant health problem. Due to the problems encountered in treating infections caused by resistant strains, developing alternative treatment methods, such as Nanomaterial systems and natural agents, are important. The essential oil of Melaleuca alternifolia is used as an antibacterial and the primary active component is terpinen-4-ol. This study aimed to investigate the antibacterial and anti-biofilm activity of terpinen-4-ol and terpinen-4-ol loaded polydopamine (T-PDA) nanoparticles against S. aureus isolates, which were resistant to at least one group of antibiotics isolated from milk samples of subclinical mastitis cows. The S. aureus strains were identified by biochemical tests and verified with the API Staph kit. The antibiotic susceptibility of the isolates was determined by the disc diffusion method. The broth microdilution method determined the antimicrobial activities of the terpinen-4-ol and T-PDA nanoparticles, and anti-biofilm activities were assessed using the modified crystal violet method. All of the isolates were resistant to benzylpenicillin and susceptible to trimethoprim/sulfamethoxazole. Multi-antibiotic resistance was detected in the 11 S. aureus isolates used in this study. For the terpinen-4-ol and T-PDA nanoparticles, MIC values were determined in the range of 0.125-0.5% (µL/mL) and 0.125-0.25% (µL/mL), respectively. None of the isolates formed biofilms. As a result, it was found that the antibacterial efficacy of the T- PDA nanoparticles was higher against nine of the S. aureus isolates than against the terpinen-4-ol. [ABSTRACT FROM AUTHOR]

Listeria monocytogenes is capable of forming biofilms on the food contact surfaces, increasing the risk of food contamination by this pathogen. The disinfectant benzalkonium chloride (BC) is commonly used to control L. monocytogenes in the food industry. This study aimed to investigate effects of BC on L. monocytogenes biofilms. Biofilm biomass was measured by the microplate method with crystal violet staining. Results from the broth microdilution method showed that the minimum inhibitory concentration (MIC) of BC against L. monocytogenes 10403S was 8 μg.mL-1. Sub-MICs of BC inhibited the biofilm formation and lethal concentrations of BC removed mature biofilms of L. monocytogenes 10403S. The presence of BC reduced extracellular proteins and exopolysaccharides in biofilms. Additionally, upregulation of quorum sensing gene luxS and agrBDCA and downregulation of flagellum motility genes flaA, motA, and motB were observed in the presence of BC. The BC disinfectant has an excellent anti-biofilm activity against L. monocytogenes.

Chronic infections often involve notorious pathogens like Pseudomonas aeruginosa and Staphylococcus aureus, demanding innovative antimicrobial strategies due to escalating resistance. This investigation scrutinized the antibacterial prowess of bile salts, notably taurocholic acid (TCA), ursodeoxycholic acid (UDCA), and ox bile salt (OBS), against these pathogens. Evaluations encompassed minimum inhibitory concentration (MIC) determination, scrutiny of their impact on biofilm formation, and anti-virulence mechanisms. UDCA exhibited the highest efficacy, suppressing S. aureus and P. aeruginosa biofilms by 83.5% and 78%, respectively, at peak concentration. TCA also significantly reduced biofilm development by 81% for S. aureus and 75% for P. aeruginosa. Microscopic analysis revealed substantial disruption of biofilm architecture by UDCA and TCA. Conversely, OBS demonstrated ineffectiveness against both pathogens. Mechanistic assays elucidated UDCA and TCA’s detrimental impact on the cell membrane, prompting the release of macromolecular compounds. Additionally, UDCA and TCA inhibited protease and elastase synthesis in P. aeruginosa and staphyloxanthin and lipase production in S. aureus. These results underscore the potential of UDCA and TCA in impeding biofilm formation and mitigating the pathogenicity of S. aureus and P. aeruginosa.

We developed and evaluated several new fused imidazo[1,2‐d][1,2,4]thiadiazolo[1,2,3]triazoles to see how they perform against bacteria and biofilms. Some compounds showed acceptable activity compared to the primary standard, Dicloxacillin. Some of the compounds demonstrated significant antibacterial activity against S. aureus, with MIC values ranging from 1.56–12.5 μg/mL. We also found anti‐biofilm properties in the potent compounds. The results showed that derivatives 3‐(4‐fluorophenyl)imidazo[1,2‐d] [1,2,3] triazolo[1,5‐b][1,2,4]thiadiazole 8,8‐dioxide and 3‐(3,5‐difluorophenyl)imidazo[1,2‐d][1,2,3]triazolo[1,5‐b][1,2,4] thiadiazole 8,8‐dioxide were strong antibacterial agents and effective MSSA and MRSA biofilm growth inhibitors. We conducted in silico studies to assess the molecular interactions of more potent compounds with TLR4 proteins (PDB: 3FXI, 3VQ1, 3RG1). Our findings revealed that 3‐(4‐chloro‐3,5‐dimethoxyphenyl)imidazo[1,2‐d][1,2,3]triazolo[1,5‐b] [1,2,4]thiadiazole 8,8‐dioxide, 3‐(3,5‐dichlorophenyl)imidazo[1,2‐d] [1,2,3]triazolo[1,5‐b][1,2,4] thiadiazole 8,8‐dioxide, and 3‐(4‐(trifluoromethyl)phenyl)imidazo[1,2‐d][1,2,3]triazolo[1,5‐b][1,2,4] thiadiazole 8,8‐dioxide exhibited more binding interactions than dicloxacillin. ADME of more potent compounds examined in this study and compounds could potentially inhibit the cytochrome P450 CYP2C19 isoform. [ABSTRACT FROM AUTHOR]

Lactic acid bacteria (LAB) are the most common probiotics, and they present excellent inhibitory effects on pathogenic bacteria. This study aimed to explore the anti-biofilm potential of the purified active substance of Lactiplantibacillus plantarum, named Z102-E. The effects of Z102-E on Listeria monocytogenes were investigated in detail, and a transcriptomic analysis was conducted to reveal the anti-biofilm mechanism. The results indicated that the sub-MIC of Z102-E (3.2, 1.6, and 0.8 mg/mL) decreased the bacterial growth and effectively reduced the self-aggregation, surface hydrophobicity, sugar utilization, motility, biofilm formation, AI-2 signal molecule, contents of extracellular polysaccharides, and extracellular protein of L. monocytogenes. Moreover, the inverted fluorescence microscopy observation confirmed the anti-biofilm effect of Z102-E. The transcriptomic analysis indicated that 117 genes were up-regulated and 214 were down-regulated. Z102-E regulated the expressions of genes related to L. monocytogenes quorum sensing, biofilm formation, etc. These findings suggested that Z102-E has great application potential as a natural bacteriostatic agent. [ABSTRACT FROM AUTHOR]

Aims This study aimed to investigate the effect of Oliveria decumbens essential oil (Od- EO) on the phenotypic properties and gene expression of Staphylococcus aureus biofilm on commonly used food contact surfaces. Methods and results The minimum inhibitory concentration and minimum bactericidal concentration of Od-EO on S. aureus ATCC25923 were determined to be 0.5 and 1 µl/ml, respectively. Crystal violet staining, scanning electron microscopy (SEM), biofilm metabolic activity evaluation, and real-time PCR analysis were used to assess the anti-biofilm properties of Od- EO. The results demonstrated that Od- EO exhibited significant anti-biofilm properties against S. aureus and effectively reduced the metabolic activity of biofilm cells. Furthermore, the inhibitory effects of Od- EO on biofilm formation were more pronounced on stainless steel (SS) compared to high-density polyethylene (HDPE) surfaces. Real-time PCR analysis revealed that Od- EO downregulated the expression of biofilm-related genes (icaA, icaD, clfA, clfB, FnbA, FnbB , and hld) in S. aureus grown on SS, while the expression levels of all studied genes except hld in the biofilm formed on HDPE remained unchanged or increased. Conclusions One of the main anti-biofilm mechanisms of the Od-EO on the HDPE is related to the disturbance in the QS of the cells. These findings highlight the potential of Od- EO as an effective agent for controlling and inhibiting S. aureus biofilm in the food industry and its potential use in disinfectant compounds. [ABSTRACT FROM AUTHOR]

Chronic periprosthetic joint infection (PJI) is a major complication of total joint arthroplasty. The underlying pathogenesis often involves the formation of bacterial biofilm that protects the pathogen from both host immune responses and antibiotics. The gold standard treatment requires implant removal, a procedure that carries associated morbidity and mortality risks. Strategies to preserve the implant while treating PJI are desperately needed. Our group has developed an anti-biofilm treatment, PhotothermAA gel, which has shown complete eradication of 2-week-old mature biofilm in vitro. In this study, we tested the anti-biofilm efficacy and safety of PhotothermAA in vivo when combined with debridement, antibiotics and implant retention (DAIR) in a rabbit model of knee PJI. New Zealand white rabbits (n = 21) underwent knee joint arthrotomy, titanium tibial implant insertion, and inoculation with Xen36 (bioluminescent Staphylococcus aureus) after capsule closure. At 2 weeks, rabbits underwent sham surgery (n = 6), DAIR (n = 6), or PhotothermAA with DAIR (n = 9) and were sacrificed 2 weeks later to measure implant biofilm burden, soft-tissue infection, and tissue necrosis. The combination of anti-biofilm PhotothermAA with DAIR significantly decreased implant biofilm coverage via scanning electron microscopy compared to DAIR alone (1.8 versus 81.0%; P <.0001). Periprosthetic soft-tissue cultures were significantly decreased in the PhotothermAA with DAIR treatment group (log reduction: Sham 1.6, DAIR 2.0, combination 5.6; P <.0001). Treatment-associated necrosis was absent via gross histology of tissue adjacent to the treatment area (P =.715). The addition of an anti-biofilm solution like PhotothermAA as a supplement to current treatments that allow implant retention may prove useful in PJI treatment. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa is an opportunistic pathogen in humans and a frequent cause of severe nosocomial infections and fatal infections in immunocompromised individuals. Its ability to form biofilms has been the main driving force behind its resistance to almost all conventional antibiotics, thereby limiting treatment efficacy. In an effort to discover novel therapeutic agents to fight P. aeruginosa-associated biofilm infections, the truncated analogs of scorpion venom-derived peptide IsCT were synthesized and their anti-biofilm properties were examined. Among the investigated peptides, the IsCT-Δ6-8 peptide evidently showed the most potential anti-P. aeruginosa biofilm activity and the effect was not due to bacterial growth inhibition. The IsCT-Δ6-8 peptide also exhibited inhibitory activity against the production of pyocyanin, an important virulence factor of P. aeruginosa. Furthermore, the IsCT-Δ6-8 peptide significantly suppressed the production of inflammatory mediators nitric oxide and interleukin-6 in P. aeruginosa LPS-induced macrophages. Due to its low cytotoxicity to mammalian cells, the IsCT-Δ6-8 peptide emerges as a promising candidate with significant anti-biofilm and anti-inflammatory properties. These findings highlight its potential application in treating P. aeruginosa-related biofilm infections. [ABSTRACT FROM AUTHOR]

The escalation in infections from World Health Organization (WHO)‐listed priority pathogens has made development of new antibacterial agents a critical priority. In this context, use of therapeutic secondary metabolites (SMs) from Actinobacteria as new drugs presents a promising avenue. However, majority of them fail to reach market due to low aqueous solubility and hence low bioavailability. Even though nanosuspension technology has been effectively used to address these challenges, use of this technology for nanox02010;listed priority pathogens has made development of new antibacterial agents a critical priority. In thitransformation of crude metabolites from Actinobacteria is still an unattempted area. Herein, for the first time, development of water‐soluble nanosuspension of water‐insoluble therapeutic metabolites produced by Streptomyces californicus strain ADR1 to develop a biocompatible material to be used as potential nanomedicine is reported. The nanosuspension (N‐SM) is characterized by UV‐vis spectroscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and dynamic light scattering (DLS). The nanosuspension reduces the MIC values by 50% against Gram‐positive priority pathogens and eradicates established biofilms with fivefold efficiency incomparison to SMs. The nanosuspension also displays antioxidant activity. The findings open up future possibilities of using this novel nanosuspension as an effective antibacterial agent in various therapeutic and biomedical applications like wound dressings, coatings on medical equipment, and surgical implants. [ABSTRACT FROM AUTHOR]

Introduction Nanoniosomes are multi-layered vesicles that are used as one of the new targeted drug delivery systems today. In this study, the extract of the Artemisia deserti L. was encapsulated in nanonisomes and its antimicrobial and cytotoxic effects were studied. Materials and Methods In this experimental study, nanonisomes containing the extract of Artemisia deserti were synthesized and their appearance and structural characteristics were investigated. After confirming the structure, its antimicrobial and anti-biofilm effects on Klebsiella pneumoniae pathogenic strains were investigated. Finally, in order to check the biocompatibility, the colorimetric method of nanonisomes cytotoxicity was used on HFF normal fibroblast cell line. Results The results of niosomes synthesis showed that the synthesized nanoniosomes have a spherical structure and have a size of 125.4 ± 29.3 nm. In addition, FTIR results confirmed the synthesis of niosomes. The results of the antimicrobial effects showed that the nanoniosomes containing the medicinal extract have more significant antimicrobial and anti-biofilm effects than the extract alone, so that the minimum inhibitory concentration (MIC) of the niosomes was reduced between 2 and 4 times. Also, the cytotoxicity results showed that the synthesized niosomes do not have significant cytotoxicity effects. Conclusion In general, the results of this study showed that nanonisomes can act as a suitable drug delivery system for medicinal plant extract to increase the amount of antimicrobial and anti-biofilm effects. Therefore, with further studies, this system can be used as an optimal drug delivery system for medicinal purposes. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa is a Gram-negative pathogenic bacterium commonly found in healthcare centers, and is known for its ability to form biofilms, its virulence controlled by quorum sensing systems (QS). The aim of this study was to investigate the antimicrobial synergistic potential of sulfated polysaccharides (SPs) extracted from the green alga Enteromorpha intestinalis and to examine the effect of SPs on the QS phenotype and biofilm formation ability of Pseudomonas aeruginosa ATCC 10145. The extracted SPs combined with ceftazidime exhibited a significant antibiotic effect against P. aeruginosa, increasing its bactericidal activity up to nine times. In addition, concentrations below the minimum inhibitory concentration (MIC) of the extracted SPs (5 and 10 µg/ml) successfully reduced pyocyanin and rhamnolipid production, swimming motility, protease activity, and biofilm formation ability compared to the control group (P < 0.05). It appears that SPs extracted from green algae have significant potential as a coating agent for surgical equipment, effectively preventing hospital-acquired infections caused by the pathogenic bacterium P. aeruginosa. [ABSTRACT FROM AUTHOR]

In the present study, magnesium nanoparticles (Mg NPs) were synthesized utilizing an aqueous extract of Berberis aristate rhizome and evaluated for antimicrobial and anti-inflammatory activity. Technofunctional properties of rhizome powder were evaluated and during thermal stability evaluation four stages of decomposition with a maximum delta Y value of 76.04 % was observed. Optimization of Mg NPs was carried out by employing eight different concentrations (C1-C8) and the C4 showed maximum absorbance at 330 nm confirming the NPs synthesis. The Mg NPs showed the particle size of 62 nm, zeta potential of −24.7 mV and hexagonal mprphology. Potential inhibition against S. aureus and E. coli (76.78 ± 0.05% and 74.62 ± 0.17%)and anti-inflammatory activity ranging from 42.43 ± 0.07–82.92 ± 0.04% was observed for Mg NPs. Therefore, green synthesis of Mg NPs is a promising approach for the development ofbiological active NPs to cure microbial infections. [ABSTRACT FROM AUTHOR]

Background: Antimicrobial‐resistant Helicobacter pylori (H. pylori) poses a significant public health concern, especially given the limited therapeutic options for azithromycin‐resistant strains. Hence, there is a necessity for new studies to reconsider the use of azithromycin, which has diminished in effectiveness against numerous strains. Thus, we aimed to augment azithromycin's anti‐Helicobacter properties by combining it with curcumin in different formulations, including curcumin in clove oil, curcumin nano‐gold emulsion, and curcumin nanoemulsion. Methods: The antimicrobial activities of the investigated compounds, both individually and in combination with other anti‐Helicobacter drugs, were evaluated. Their antibiofilm and anti‐virulence properties were assessed using both phenotypic and genotypic methods, alongside molecular docking studies. Our findings were further validated through mouse protection assays and histopathological analysis. Results: We observed high anti‐Helicobacter activities of curcumin, especially curcumin nanoemulsion. A synergistic effect was detected between curcumin nanoemulsion and azithromycin with fraction inhibitory concentration index (FICI) values <0.5. The curcumin nanoemulsion was the most active anti‐biofilm and anti‐virulence compound among the examined substances. The biofilm‐correlated virulence genes (babA and hopQ) and ureA genes were downregulated (fold change <1) post‐treatment with curcumin nanoemulsion. On the protein level, the anti‐virulence activities of curcumin nanoemulsion were documented based on molecular docking studies. These findings aligned with histopathological scoring of challenge mice, affirming the superior efficacy of curcumin nanoemulsion/azithromycin combination. Conclusion: The anti‐Helicobacter activities of all curcumin physical forms pose significant challenges due to their higher minimum inhibitory concentration (MIC) values exceeding the maximum permissible level. However, using curcumin nanoemulsion at sub‐MIC levels could enhance the anti‐Helicobacter activity of azithromycin and exhibit anti‐virulence properties, thereby improving patient outcomes and addressing resistant pathogens. Therefore, more extensive studies are necessary to assess the safety of incorporating curcumin nanoemulsion into H. pylori treatment. [ABSTRACT FROM AUTHOR]

Pathogenic bacteria and their biofilms are involved in many diseases and represent a major public health problem, including the development of antibiotic resistance. These biofilms are known to cause chronic infections for which conventional antibiotic treatments are often ineffective. The search for new molecules and innovative solutions to combat these pathogens and their biofilms has therefore become an urgent need. The use of molecules with anti-biofilm activity would be a potential solution to these problems. The marine world is rich in micro- and macro-organisms capable of producing secondary metabolites with original skeletons. An interest in the chemical strategies used by some of these organisms to regulate and/or protect themselves against pathogenic bacteria and their biofilms could lead to the development of bioinspired, eco-responsible solutions. Through this original review, we listed and sorted the various molecules and extracts from marine organisms that have been described in the literature as having strictly anti-biofilm activity, without bactericidal activity. [ABSTRACT FROM AUTHOR]

Background: Biofilm formation on biomedical devices is a prevalent problem that can result in several complications and is responsible for over 80% of all clinical infections. Successful treatment of biofilms requires a 1500-fold increase in antibiotic concentration, which can lead to toxicity and antibiotic resistance. Therefore, biofilm growth and infection in biomedical devices are significant concerns, and their prevention is a crucial medical challenge. Objectives: To prevent biofilm infection by modifying the surface properties of medical devices, an oleamide–polydimethylsiloxane (PDMS) copolymer was synthesized to demonstrate anti-adhesion to bacteria and anti-biofilm activity. Catheter coatings for biomedical device applications were evaluated by blood toxicity. Results: We synthesized an oleamide–PDMS copolymer (OPC) and evaluated its anti-adhesion and anti-biofilm activities against the gram-negative bacterium Escherichia coli (E. coli) and the gram-positive bacterium Staphylococcus aureus (S. aureus). The OPC films inhibited the growth of biofilms by inhibiting early adhesion of bacteria. As the oleamide content increased, the ability of the OPC films to inhibit E. coli and S. aureus surface adhesion also increased. In addition, the biofilm formation ability of both E. coli and S. aureus was significantly inhibited at oleamide contents of 2.5 wt% and 5 wt% in the OPC films, respectively. OPC films were applied to the catheter using a simple dip-coating method, and a low hemolytic capacity was confirmed by hemolysis analysis. Conclusion: The anti-adhesion ability of OPC enables them to prevent biofilm growth and infection. Furthermore, they can be applied in medical devices owing to their high biocompatibility and poor hemolytic properties. [ABSTRACT FROM AUTHOR]

Tetrahedral amorphous carbon (taC) is a hydrogen-free carbon with extensive properties such as hardness, optical transparency, and chemical inertness. taC coatings have attracted much attention in recent times, as have coatings doped with a noble metal. A known antimicrobial metal agent, silver (Ag), has been used as a dopant in taC, with different Ag concentrations on the Ti64 coupons using a hybrid filtered cathodic vacuum arc (FCVA) and magnetron sputtering system. The physiochemical properties of the coated surface were investigated using spectroscopic and electron microscopy techniques. A doping effect of Ag-taC on biofilm formation was investigated and found to have a significant effect on the bacterial-biofilm-forming bacteria Staphylococcus aureus and Pseudomonas aeruginosa depending on the concentration of Ag. Further, the effect of coated and uncoated Ag-taC films on a pathogenic bacterium was examined using SEM. The result revealed that the Ag-taC coatings inhibited the biofilm formation of S. aureus. Therefore, this study demonstrated the possible use of Ag-taC coatings against biofilm-related complications on medical devices and infections from pathogenic bacteria. [ABSTRACT FROM AUTHOR]

Aim Isolation, identification, structural and functional characterization of potent anti- Candida compound with specific antagonistic activities against significant human pathogens, Candida albicans and C. auris. Methods and Results The compound (55B3) was purified from the metabolites produced by Streptomyces chrestomyceticus ADP4 by employing column chromatography. The structure of 55B3 was determined from the analyses of spectral data that included LCMS, nuclear magnetic resonance, FTIR, and UV spectroscopies. It was identified as a novel derivative of diterpenic aromatic acid, 3-(dictyotin-11′-oate-15′α, 19′β-olide)-4-(dictyotin-11′-oate-15″α, 19″β-olide)-protocatechoic acid. The compound displayed potent antifungal and anti-biofilm activities against C. albicans ATCC 10231 (Minimum Inhibitory Concentration, MIC90:14.94 ± 0.17 μgmL−1 and MBIC90: 16.03 ± 1.1 μgmL−1) and against C. auris CBS 12372 (MIC90: 21.75 ± 1.5 μgmL−1 and Minimum Biofilm Inhibitory Concentration, MBIC90: 18.38 ± 1.78 μgmL−1). Further, pronounced inhibition of important virulence attributes of Candida spp. e.g. yeast-to-hyphae transition, secretory aspartyl proteinase and phospholipase B by 55B3 was noted at subinhibitory concentrations. A plausible mechanism of anti- Candida action of the compound appeared to be the inhibition of ergosterol biosynthesis, which was inhibited by 64 ± 3% at the MIC90 value. The non-cytotoxic attribute of the compound was noted in the liver cell line (HepG2 cells). Conclusion The present work led to the discovery of a novel diterpenic derivative produced by S. chrestomyceticus ADP4. The compound displayed potent anti- Candida activity, particularly against the two most significant human pathogens, C. albicans and C. auris , which underlined its significance as a potential drug candidate for infections involving these pathogens. [ABSTRACT FROM AUTHOR]

Scientific researches on the synthesis, characterisation, and biological activity of potassium nanoparticles (K NPs) are extremely rare. In our study, we successfully synthesised a novel form of K NPs using Capparis spinosa (C. spinosa) flower extract as a reducing and capping agent. The formation of K NPs in new form (K2O NPs) was confirmed by UV–vis and XRD spectra. Furthermore, the FTIR results indicated the presence of specific active biomolecules in the C. spinosa extract which played a crucial role in reducing and stabilising K2O NPs. SEM imaging demonstrated that the K2O NPs exhibited irregular shapes with nanosizes ranging between 25 and 95 nm. Remarkably, the biosynthesised K2O NPs displayed considerable antibacterial activity against a wide range of multidrug-resistant (MDR) pathogenic bacteria. K2O NPs demonstrated considerable anti-biofilm activity against preformed biofilms produced by MDR bacteria. Combining K2O NPs with conventional antibiotics greatly improved their efficacy in compacting the MDR bacterial strains. Industrially, bulk form of potassium oxides was commonly used in the preparation of various antimicrobial compounds such as detergents, bleach, and oxidising solutions. The synthesis of potassium oxide in nanoform has shown remarkable biological efficacy, making it a promising therapeutic approach for pharmaceutical and medical applications. [ABSTRACT FROM AUTHOR]

Dental caries is a global health problem that requires better prevention measures. One of the goals is to reduce the prevalence of the cariogenic Gram-positive bacterium Streptococcus mutans. We have recently shown that naturally occurring arachidonic acid (AA) has both anti-bacterial and anti-biofilm activities against this bacterium. An important question is how these activities are affected by other anti-bacterial compounds commonly used in mouthwashes. Here, we studied the combined treatment of AA with chlorhexidine (CHX), cetylpyridinium chloride (CPC), triclosan, and fluoride. Checkerboard microtiter assays were performed to determine the effects on bacterial growth and viability. Biofilms were quantified using the MTT metabolic assay, crystal violet (CV) staining, and live/dead staining with SYTO 9/propidium iodide (PI) visualized by spinning disk confocal microscopy (SDCM). The bacterial morphology and the topography of the biofilms were visualized by high-resolution scanning electron microscopy (HR-SEM). The effect of selected drug combinations on cell viability and membrane potential was investigated by flow cytometry using SYTO 9/PI staining and the potentiometric dye DiOC2(3), respectively. We found that CHX and CPC had an antagonistic effect on AA at certain concentrations, while an additive effect was observed with triclosan and fluoride. This prompted us to investigate the triple treatment of AA, triclosan, and fluoride, which was more effective than either compound alone or the double treatment. We observed an increase in the percentage of PI-positive bacteria, indicating increased bacterial cell death. Only AA caused significant membrane hyperpolarization, which was not significantly enhanced by either triclosan or fluoride. In conclusion, our data suggest that AA can be used together with triclosan and fluoride to improve the efficacy of oral health care. [ABSTRACT FROM AUTHOR]

BackgroundThe emergence of multidrug-resistant bacteria and also biofilm-associated infections is a great health concern due to the failure of available antibiotics. This has alerted scientists to developing alternative antibiotics. Melittin as an antimicrobial peptide has antibacterial synergistic activity in combining with conventional antibiotics against pathogenic bacteria. Accordingly, this study aimed to assess the synergistic effect of melittin in combination with Ciprofloxacin, Rifampicin, and Chloramphenicol against MDR strains of P. aeruginosa.Materials and methodsFifty strains of P. aeruginosa were isolated from clinical specimens. The antibiotic susceptibility of isolates was evaluated by the disk diffusion method. The MIC and MBC of melittin and melittin-antibiotics combination against isolated strains were examined by microdilution method. The probable synergism between melittin and antibiotics was assayed using the FIC protocol. Time-killing kinetics and anti-biofilm effects of melittin and melittin-antibiotics combination were evaluated using time-kill kinetics and crystal violet staining method, respectively. The toxicity of the melittin-antibiotics combination on the HEK293 cell line was also assessed by the MTT assay method.ResultsOut of 50 isolates of P. aeruginosa, 15 strains are considered to be multidrug strains. Among MDR strains of P. aeruginosa, 42.85% were resistant to cefepime and ceftazidime and all urine-originate isolates were resistant to cotrimoxazole. A combination of MIC dose of ciprofloxacin and melittin decreased resistance against ciprofloxacin up to 33%. The ciprofloxacin-melittin combination showed a favorable synergism and anti-biofilm effect and was also 30.3% less toxic than melittin alone at 4 μg/ml against the HEK293 cell line. In contrast to ciprofloxacin, with the melittin-rifampicin and melittin-chloramphenicol combinations, an addition effect occurred, respectively, in 86.66 and 53.33% of MDR strains of P. aeruginosa.ConclusionCombining melittin’s antibacterial and anti-biofilm properties with traditional antibiotics may offer a novel strategy to address antibiotic resistance in P. aeruginosa. The simultaneous administration of melittin and ciprofloxacin in a single dose has shown a marked increase in antibacterial effectiveness while minimizing toxicity to the HEK293 cell line. It is advisable to conduct additional research to explore the combined antibacterial effects of melittin and ciprofloxacin in a wider range of clinical samples, animal models, and clinical trial settings.

Ag NPs have garnered significant attention in the field of biomedical applications due to their antibacterial, antifungal, antiviral, anti-inflammatory, and antiangiogenic effects. The present study aimed to establish a simple, reliable, cost-effective, and environmentally friendly approach for the synthesis of Ag NPs in different sizes using extracts from Syzygium aromaticum and Laurus nobilis and study the relationship between the size of Ag NPs and their antibacterial and anti-biofilm effectiveness. The synthesized Ag NPs were extensively characterized using various techniques, such as XRD, SEM, UV–vis and FTIR. Importantly, the study evaluated the antibacterial and anti-biofilm activities of Ag NPs in two different size (12 nm and 45 nm) against MDR and biofilm-producing pathogenic bacteria, including Kocuria rosea, Staphylococcus sciuri, and Staphylococcus lentus. The antibacterial activity of the larger Ag NPs-SA (45 nm) ranging between 14–25 mm while for the smaller Ag NPs-LN (12 nm) ranging between 26–48 mm against pathogenic bacteria. The MIC values for Ag NPs-LN were between 16 - 32 µg/ml while for Ag NPs-SA were 64 µg/ml. The MIC value of the Ag NPs decreased as their size decreased, indicating higher potency against the tested bacterial strains. Furthermore, the smaller Ag NPs-LN exhibited a higher rate of biofilm inhibition that reach 88% compared to the larger Ag NPs that reach 70%. This study provides novel evidence that the enhanced antibacterial and anti-biofilm activities of Ag NPs are directly correlated with their decreased nanoscale size. These findings highlight the potential of Ag NPs as a promising adjuvant in the management of bacterial infections, particularly those involving MDR and biofilm-producing pathogens, which pose a significant challenge in clinical settings.

ABSTRACT With the widespread misuse of disinfectants, the clinical susceptibility of Klebsiella pneumoniae (K. pneumoniae) to chlorhexidine (CHX) has gradually diminished, posing significant challenges to clinical disinfection and infection control. K. pneumoniae employs overexpression of efflux pumps and the formation of thick biofilms to evade the lethal effects of CHX. Plumbagin (PLU) is a natural plant extract that enhances membrane permeability and reduces proton motive force. In this study, we elucidated the synergistic antimicrobial activity of PLU in combination with CHX, effectively reducing the MIC of CHX against K. pneumoniae to 1 µg/mL and below. Crucially, through crystal violet staining and confocal laser scanning microscopy live/dead staining, we discovered that PLU significantly enhances the anti-biofilm capability of CHX. Mechanistically, experiments involving membrane permeability, alkaline phosphatase leakage, reactive oxygen species, and RT-qPCR suggest that the combination of PLU and CHX improves the permeability of bacterial inner and outer membranes, promotes bacterial oxidative stress, and inhibits oqxA/B efflux pump expression. Furthermore, we conducted surface disinfection experiments on medical instruments to simulate clinical environments, demonstrating that the combination effectively reduces bacterial loads by more than 3 log10 CFU/mL. Additionally, results from resistance mutation frequency experiments indicate that combined treatment reduces the generation of resistant mutants within the bacterial population. In summary, PLU can serve as an adjuvant, enhancing the anti-biofilm capability of CHX and reducing the occurrence of resistance mutations, thereby extending the lifespan of CHX.IMPORTANCEAs disinfectants are extensively and excessively utilized worldwide, clinical pathogens are progressively acquiring resistance against these substances. However, high concentrations of disinfectants can lead to cross-resistance to antibiotics, and concurrent use of different disinfectants can promote bacterial resistance mutations and facilitate the horizontal transfer of resistance genes, which poses significant challenges for clinical treatment. Compared with the lengthy process of developing new disinfectants, enhancing the effectiveness of existing disinfectants with natural plant extracts is important and meaningful. CHX is particularly common and widely used compared with other disinfectants. Meanwhile, Klebsiella pneumoniae, as a clinically significant pathogen, exhibits high rates of resistance and pathogenicity. Previous studies and our data indicate a significant decrease in the sensitivity of clinical K. pneumoniae to CHX, highlighting the urgent need for novel strategies to address this issue. In light of this, our research is meaningful.

ABSTRACT Wound infections, exacerbated by the prevalence of antibiotic-resistant bacterial pathogens, necessitate innovative antimicrobial approaches. Polymicrobial infections, often involving Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA), present challenges due to biofilm formation and antibiotic resistance. Hypochlorous acid (HOCl), a potent antimicrobial agent, holds promise as an alternative therapy. An electrochemical bandage (e-bandage) that generates HOCl in situ via precise polarization controlled by a miniaturized potentiostat was evaluated for the treatment of murine wound biofilm infections containing both P. aeruginosa with “difficult-to-treat” resistance and MRSA. Previously, HOCl-producing e-bandage was shown to reduce murine wound biofilms containing P. aeruginosa alone. Here, in 5-mm excisional skin wounds containing 48-h biofilms comprising MRSA and P. aeruginosa combined, polarized e-bandage treatment reduced MRSA by 1.1 log10 CFU/g (P = 0.026) vs non-polarized e-bandage treatment (no HOCl production), and 1.4 log10 CFU/g (0.0015) vs Tegaderm only controls; P. aeruginosa was similarly reduced by 1.6 log10 CFU/g (P = 0.0032) and 1.6 log10 CFU/g (P = 0.0015), respectively. For wounds infected with MRSA alone, polarized e-bandage treatment reduced bacterial load by 1.1 log10 CFU/g (P = 0.0048) and 1.3 log10 CFU/g (P = 0.0048) compared with non-polarized e-bandage and Tegaderm only, respectively. The e-bandage treatment did not negatively impact wound healing or cause tissue toxicity. The addition of systemic antibiotics did not enhance the antimicrobial efficacy of e-bandages. This study provides additional evidence for the HOCl-producing e-bandage as a novel antimicrobial strategy for managing wound infections, including in the context of antibiotic resistance and polymicrobial infections.IMPORTANCENew approaches are needed to combat the rise of antimicrobial-resistant infections. The HOCl-producing electrochemical bandage (e-bandage) leverages in situ generation of HOCl, a natural biocide, for broad-spectrum killing of wound pathogens. Unlike traditional therapies that may exhibit limited activity against biofilms and antimicrobial-resistant organisms, the e-bandage offers a potent, standalone solution that does not contribute to further resistance or require adjunctive antibiotic therapy. Here, we show the ability of the e-bandage to address polymicrobial infection by antimicrobial resistant clinical isolates of Staphylococcus aureus and Pseudomonas aeruginosa, two commonly isolated, co-infecting wound pathogens. Effectiveness of the HOCl-producing e-bandage in reducing pathogen load while minimizing tissue toxicity and avoiding the need for systemic antibiotics underscores its potential as a tool in managing complex wound infections.

Medical companies and research centers seek cost-effective alternative culture media containing the necessary nutritional requirements for bacterial cultivation because of high manufacturing and production costs. Date palm pollen (DPP) is an inexpensive and rich natural plant resource that can be easily collected in large quantities. In this study, DPP was used to prepare a novel enriched culture medium that successfully cultivated pathogenic bacteria and Streptomyces spp. without any additives and at a low concentration of 10 g per 1 L of distilled water (DW). Active compounds in DPP were detected by GCMS–, and results show the highest ratio of urea (45 %) among other components. For the first time, DPP was used to synthesize Cr2O3 NPs by an environment-friendly and inexpensive green method. DPP urea plays an important role as a reducing and stabilizing agent in the biosynthesis of Cr2O3 NPs. The obtained NPs were characterized using UV–Vis, FTIR, XRD and SEM. The results of agar disk diffusion ranging between 12 – 20 mm while the MIC for Cr2O3 NPs ranging between 1.56 – 25 U/mL indicated the effectiveness of Cr2O3 NPs in antibacterial activity against a wide range of pathogenic bacteria. Cr2O3 NPs showed a high inhibition ratio that reach 78 % against biofilms produced by P. aeruginosa. For later studies we expect that DPP can be used to prepare selective and other culture media after adding certain materials or antibiotics. The antibacterial and anti-biofilm activity of Cr2O3 NPs could be promising in medical and pharmaceutical applications.