Biofilm Destruction Research Articles

Antibiofilm and Anticancer Activity of Multi-Walled Carbon Nanotubes Fabricated with Hot-Melt Extruded Astaxanthin-Mediated Synthesized Silver Nanoparticles.

Multi-walled carbon nanotubes (MWCNTs) were used as carriers for silver nanoparticles (AgNPs). In this process, MWCNTs were coated with mesoporous silica (MWCNT-Silica) for uniform and regular loading of AgNPs on the MWCNTs. In addition, astaxanthin (AST) extract was used as a reducing agent for silver ions to enhance the antioxidant, antibiofilm, and anticancer activities of AgNPs. In this process, AST was extracted from Haematococcus pluvialis (H. pluvialis) and processed by hot melt extrusion (HME) to enhance the AST content of H. pluvialis. AST has strong antioxidative properties, which leads to anticancer activity. In addition, AgNPs are well known for their strong antibacterial properties. The antibiofilm and anticancer effects were studied comprehensively by loading the AST AgNPs onto MWCNT-Silica. AgNPs-loaded MWCNT-silica (MWCNT-Ag) was prepared through the binding reaction of TSD and silanol groups and the aggregation interaction of Ag and TSD. To enhance the antioxidant, antibiofilm, and anticancer activities of AgNPs, HME-treated H. pluvialis extract (HME-AST) was used as a reducing solution of silver ions. The increased AST content of HME-AST was confirmed by high-performance liquid chromatography (HPLC) analysis, and the total phenol and flavonoid content analysis confirmed that HME enhanced the active components of H. pluvialis. The antibiofilm activity of MWCNT-AST was investigated by biofilm inhibition and destruction test, SEM, and CLSM analysis, and the anticancer activity was investigated by WST assay, fluorescent staining analysis, and flow cytometry analysis. MWCNT-AST showed higher antioxidant activity and antibiofilm activity than MWCNT-Ag against E. coli, S. aureus, and methicillin-resistant S. aureus (MRSA). MWCNT-AST showed higher anticancer activity against breast cancer cells (MDA-MB-231) than MWCNT-Ag, and lower toxicity in normal cells HaCaT and NIH3T3. MWCNT-AST exhibits higher antioxidant, antibiofilm, and anticancer activities than MWCNT-Ag, and exhibits lower toxicity to normal cells.

Silver nanoparticles/carbon dots nanocomposite with potent antibiofilm and long-term antimicrobial activity doped into chitosan/polyvinyl alcohol film for food preservation.

Exploration of robust antiseptics with antibiofilm performance and long-term antimicrobial activity is of great significance to effectively destroy foodborne pathogenic bacteria. Herein, a silver nanoparticles (Ag NPs) /carbon dots (CDs) nanocomposite (Ag@CDs) was constructed by the reaction of Ag+ with CDs, which has strong antibacterial ability, and mighty biofilm inhibition and destruction ability toward E. coli and S. aureus. Notably, low concentration of Ag@CDs (40.0 and 80.0μg/mL) could ablate 86.11% E. coli and 75.86%S. aureus biomass of mature biofilm. To our knowledge, this is the first bactericide with powerful biofilm destruction activity. In addition, Ag@CDs exhibited long-term (30 d) antibacterial effect on the substrates of plastic, cotton, gauze, and glass. Ag@CDs was evenly dispersed into the matrix of chitosan (CS)/polyvinyl alcohol (PVA) to fabricate well-blended food packaging films. Among which, the 3% Ag-CP film exhibited improved mechanical performance, excellent UV-Vis light blocking ability, and intensive antimicrobial activity. Despite seven days of storage, 3% Ag-CP still could preserve the freshness and safety of the pork and shrimp, certifying it extends the storage life of packaged foods.

The effect of antibacterial peptide ε-Polylysine against Pseudomonas aeruginosa biofilm in marine environment

Natural antibacterial agents with antimicrobial properties have a broad potential to prevent bacterial from forming biofilms adhesion in marine environments. ε-Polylysine (E-PL) consist of homomeric polymer with 25–30 lysine residues with stability, nontoxicity, and biodegradability. ε-Polylysine is a natural cationic antibacterial peptide that can resist microbial forming biofilm adhesion. The current study investigated the action of E-PL against Pseudomonas aeruginosa biofilm isolated from a marine environment. Crystal violet staining was used to examine the effects of E-PL on the formation and destruction of mature biofilms. Scanning Electron and fluorescence microscopy revealed that E-PL treatment damaged the biofilm structure and affected the secretion of extracellular polymers. The CCK8 colorimetric assay showed that E-PL also decreased the metabolic activity and motility of biofilm bacteria. QPCR and transcriptome analysis revealed that E-PL affected biofilm formation and transcriptional regulation by downregulating genes involved in flagellar synthesis (flgE, PA4651, pilW), chemotaxis transduction (PA1251, PA4951, PA4788), biofilm biosynthesis (pelC, pelD, pslK, plsM), transcriptional regulation (PA3973, PA3508, PA0268), phenazine biosynthesis (phzM, phzH, phzS), and electron transfer (PA5401, PA5400, PA3492). This study used multiple methods to identify the mechanism of E-PL action against biofilm, informing the design of novel biofilm treatment methods.

Effect of combinations of antibiotics, phages, and depolymerase on biofilms of the drug-resistant Klebsiella pneumoniae strain

Introduction. Klebsiella pneumoniae poses a serious threat to global healthcare due to the high proportion of multidrug-resistant isolates. Moreover, the formation of biofilms by bacteria significantly complicates the treatment of infections.Objective. To evaluate the effectiveness of the individual and combined action of antibiotics and bacteriophages or polysaccharide depolymerase on biofilms of a clinically significant strain K. pneumoniae.Materials and methods. The work used the K. pneumoniae strain with multidrug resistance (9faiz), 4 antibiotics of various classes (gentamicin, levofloxacin, meropenem and chloramphenicol), 3 bacteriophages of various genera (Dlv622, Seu621 and FRZ284), and 1 polysaccharide depolymerase (Dep622). Experiments were carried out on the formed biofilms by treating 24-hour K. pneumoniae films with antimicrobial agents individually or in combinations. The ability of the strain to form biofilms was evaluated by staining with crystalline violet. The comparison between the average optical density values was carried out using a t-test and was considered significant at p ≤ 0.05.Results. The individual use of antibiotics peak concentrations (Cmax) or depolymerase concentration of 100 MED (minimum effective dose — MED) did not lead to a significant decrease in biofilm biomass, whereas bacteriophages in a titer of 5×109 PFU/mL (plaque-forming unit per mL) statistically significantly reduced its biomass by 27–31% (p < 0.05) Most combinations of phages and antibiotics did not lead to a significant increase in the efficiency of biofilm destruction. Only the combination of phage FRZ284 with gentamicin statistically significantly showed an additional decrease in biofilm biomass by 27% (p < 0.05).Conclusions. The results show the need for individual selection of antimicrobial combinations to combat K. pneumoniae biofilms due to the possible effect of synergy and antagonism effects on the outcome of therapy.

Supernatant of plant-associated bacteria potency against biofilms formed by foodborne pathogen and food spoilage bacteria

ObjectivesFood products are often contaminated by pathogens and spoilage bacteria. Most of them can form biofilms, a community of cells embedded in protective extracellular matrix layers resistant to harsh conditions, including antibiotics. Therefore, alternative antibiofilm agents are required to overcome biofilm formation. This study aims to determine and quantify the antibiofilm activity of supernatants from plant-associated bacteria against biofilms of foodborne pathogen and food spoilage bacterium, namely Bacillus cereus and Bacillus subtilis.ResultsPlant-associated bacteria (PAB) have shown promising antibiofilm activities against biofilm-forming pathogens in previous studies. Thirteen PAB isolated from Ternate, Indonesia were used in this study. Supernatants of PAB were subjected to antimicrobial activity and quorum quenching detection, both using the well diffusion method. Four supernatants inhibited the growth of B. subtilis, but none affected the growth of B. cereus. Eight supernatants were able to disrupt the quorum sensing system of an indicator bacterium, wild-type Chromobacterium violaceum. Biofilm inhibition and destruction were quantified using 96-well microplates. The highest biofilm inhibition and destruction activities of PAB supernatants against each of B. cereus and B. subtilis biofilms were > 76%, and were later confirmed by light microscope and scanning electron microscope. Brine shrimp lethality assay (BSLA) was conducted and revealed that the selected PAB supernatants were non-toxic. The 16S rRNA gene of PAB were sequenced and they showed similarities to Bacillus, Priestia, and Chryseobacterium. Compounds in the supernatants were determined by GC–MS which revealed contents of fatty acids, ethyl esters, and diketopiperazines. Therefore, PAB supernatants have potential as antibiofilm agents against biofilm formed by Bacillus cereus and Bacillus subtilis.

“On-demand” nanosystem-integrated microneedles for amplified triple therapy against recalcitrant bacteria and biofilm growth

Phototherapy has emerged to eradicate recalcitrant bacteria without causing drug resistance, but it is often accompanied by considerable limitations owing to a high tolerance of recalcitrant bacteria to heat and oxidative damage, leading to low efficiency of monotherapy and unwanted side effects. Assuming that employing antimicrobial peptides (AMPs) to disrupt bacterial membranes could reduce bacterial tolerance, a multifunctional “on-demand” nanosystem based on zeolitic imidazolate framework-8 (ZIF-8) with metal ions for intrinsic antibacterial activity was constructed to potently kill methicillin-resistant Staphylococcus aureus (MRSA). Then, microneedles (MNs) were used to transdermally deliver the ZIF-8-based nanosystem for localized skin infection. After MNs insertion, the nanoplatform could specifically deliver the loaded therapeutic components to bacterial infection sites through employing hyaluronic acid (HA) as a capping agent, thus realizing the “on-demand” payload release triggered by excess hyaluronidase secreted by MRSA. The prepared nanosystem and MNs were confirmed to exert an amplified triple therapy originating from membranolytic effect, phototherapy, and ion therapy, thus displaying a powerful bactericidal and MRSA biofilm destruction ability. This intelligent antimicrobial strategy may bring a dawn of hope for eradicating multidrug-resistant bacteria and biofilms.

Investigating The Synergistic and Antimicrobial Effect of Glycolipid Biosurfactants Produced by <i>Shewanella alga</i> 12B and <i>Bacillus pumilus SG</i> Bacteria with Thyme Plant Extract on Some Pathogenic Bacteria

Background: Thyme is widely recognized for its antimicrobial properties, attributed to the effective compounds present in its extract that inhibit and destroy pathogenic bacteria. Objectives: This study explores the impact of combining thyme extract with biosurfactants on pathogenic bacteria and biofilm. The biosurfactants 12B and SG have inherent antimicrobial effects, and their combination with thyme extract demonstrated synergistic effects. Methods: The experiments involved preparing methanolic thyme extract in combination with biosurfactants 12B and SG. Disk diffusion and well diffusion tests were conducted to assess the antimicrobial activity of this combination. The inhibition zones for Acinetobacterbaumannii, Bacilluscereus, Escherichiacoli, and methicillin-resistant Staphylococcusaureus (MRSA) were measured. Further tests determined the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for these bacteria. To evaluate synergistic effects, the fractional inhibitory concentration (FIC) and fractional inhibitory concentration index (FICI) were calculated. Results: The anti-biofilm effects of the biosurfactants combined with thyme extract were analyzed by testing biofilm formation inhibition, biofilm destruction, and inhibition of dehydrogenase enzyme activity within the biofilm. Biofilm assays were conducted using microplates, with readings taken at 490 nm using an ELISA reader. Conclusions: The biofilm tests demonstrated the effectiveness of thyme extract combined with biosurfactants. The results indicated that this combination exhibits antibacterial, anti-biofilm, and synergistic effects, making it effective against both antibiotic-resistant and non-resistant pathogenic bacteria.

Associations between biofilm formation and virulence factors among clinical Helicobacter pylori isolates

IntroductionHelicobacter pylori (H. pylori) causes several gastrointestinal diseases. Its virulence factors contributing to disease development include biofilm formation, cytotoxin-associated gene A (CagA) and vacuolating cytotoxin A (VacA) proteins that induce host tissue damage. In addition, urease activity enables H. pylori growth in the gastric acidic environment. This work aimed to characterize bacterial factors associated with biofilm production among 89 clinical H. pylori isolates, collected from patient gastric biopsies. MethodsBiofilm production was detected using the crystal violet method. PCR was performed to determine vacA genotype (s1m1, s1m2, s2m1 and s2m2) and cagA gene presence. Urease activity was measured via the phenol red method. Susceptibility to six antibiotics was assessed by the Etest method. ResultsMost H. pylori isolates produced biofilm. No association was found between biofilm-formation capacity and cagA presence or vacA genotype. Urease activity levels varied across isolates; no association was found between biofilm-formation and urease activity. Clarithromycin resistance was measured in 49 % of the isolates. Isolates susceptible to tetracycline were more commonly strong biofilm producers. In contrast, a significantly higher rate of strong biofilm producers was observed among resistant isolates to amoxicillin, levofloxacin and rifampicin, compared to susceptible isolates. Non-biofilm producers were more common among isolates sensitive to rifampicin and metronidazole, compared to resistant isolates. ConclusionsFurther studies are needed to understand the factors that regulate biofilm production in order to search for treatments for H. pylori biofilm destruction.

Bovine lactoferrin and chimera lactoferrin prevent and destroy Salmonella Typhimurium biofilms in Caco-2 cells.

Salmonellosis is a common foodborne disease caused by Salmonella bacteria. The emergence of multidrug-resistant (MDR) Salmonella serotypes, such as Typhimurium, and Salmonella's ability to form biofilms contribute to their resistance and persistence in host and non-host environments. New strategies are needed to treat or prevent Salmonella infections. This work aimed to determine the effect of the bovine lactoferrin (bLF) and lactoferrin chimera (LFchimera) in preventing or disrupting biofilms formed on abiotic surfaces or Caco-2 cells by S. Typhimurium ATCC 14028 or an MDR strain. The inhibitory activity of planktonic bacteria, prevention of biofilm formation, and destruction of biofilms of S. Typhimurium (ATCC 14028 or MDR strain) on the abiotic surface and Caco-2 cells of bLF and LFchimera were quantified by CFU/mL and visualized by microscopy using Giemsa-stained samples. bLF (75-1000µM) and LFchimera (1-20µM) inhibited more than 95% of S. Typhimurium planktonic growth cultures (ATCC 14028 and MDR). In addition, bLF (600, 800, and 1000µM) and LFchimera (10 and 20µM) prevented more than 98% of S. Typhimurium adherence and biofilm formation on Caco-2 cells. Finally, bLF (600 and 1000µM) and LFchimera (10 and 20µM) destroyed more than 80% of S. Typhimurium biofilms established on abiotic and Caco-2 cells. In conclusion, bLF and LFchimeras have the potential to inhibit and destroy S. Typhimurium biofilms.

2D Janus carrier-enabled trojan horse: Gallium delivery for the sequential therapy of biofilm associated infection

Biofilm-associated infections (BAIs) continue to pose a major challenge in the medical field. Nanomedicine, in particular, promises significant advances in combating BAIs through the introduction of a variety of nanomaterials and nano-antimicrobial strategies. However, studies to date have primarily focused on the removal of the bacterial biofilm and neglect the subsequent post-biofilm therapeutic measures for BAIs, rendering pure anti-biofilm strategies insufficient for the holistic recovery of affected patients. Herein, we construct an emerging dual-functional composite nanosheet (SiHx@Ga) that responds to pHs fluctuation in the biofilm microenvironment to enable a sequential therapy of BAIs. In the acidic environment of biofilm, SiHx@Ga employs the self-sensitized photothermal Trojan horse strategy to effectively impair the reactive oxygen species (ROS) defense system while triggering oxidative stress and lipid peroxidation of bacteria, engendering potent antibacterial and anti-biofilm effects. Surprisingly, in the post-treatment phase, SiHx@Ga adsorbs free pathogenic nucleic acids released after biofilm destruction, generates hydrogen with ROS-scavenging and promotes macrophage polarization to the M2 type, effectively mitigating damaging inflammatory burst and promoting tissue healing. This well-orchestrated strategy provides a sequential therapy of BAIs by utilizing microenvironmental variations, offering a conceptual paradigm shift in the field of nanomedicine anti-infectives.

Destruction of cariogenic biofilms by antimicrobial photodynamic therapy mediated by phycocyanin and toluidine blue along with sodium fluoride varnish or titanium tetrafluoride

ObjectiveEvaluation of the effect of phycocyanin (PC) and toluidine blue (TBO) along with sodium fluoride varnish (FV) or titanium tetrafluoride (TiF4) under the conditions of antimicrobial photodynamic therapy (PDT) on a dual-species cariogenic biofilm and on remineralization process. DesignAfter the development of Streptococcus mutans and Lactobacillus acidophilus dual-species biofilms on the human enamel disks, they were divided into 11 groups (n = 9): Control (0.9 % saline), PC, TBO, FV, and TiF4 alone, PC and TBO in combination with a 635 nm diode laser (PDT treatment), PC-PDT+ (PC + FV or TiF4 + 635 nm diode laser), and TBO-PDT+ (TBO + FV or TiF4 + 635 nm diode laser). After the treatment, crystal violet assay was performed to determine the reduction of cariogenic biofilms. Enamel remineralization changes were analyzed using energy dispersive X-ray spectroscopy (EDX) and field emission scanning electron microscopy (FESEM) for the calcium and phosphorus (Ca/P) ratio. ResultsOnly TBO-PDT+ showed superior antibiofilm activity when TiF4 was applied. Furthermore, the highest Ca/P ratio was found after treatment of enamel surfaces with TiF4-TBO-PDT+. The FESEM images showed that the enamel disks treated with TiF4 plus TBO-mediated PDT exhibited surface coating. However, TiF4 plus PC-mediated PDT cannot repair demineralized enamel. ConclusionsThese data suggest that TBO-PDT along with TiF4 can effectively reduce cariogenic biofilms and significantly remineralize enamel disks, opening new avenues in caries prevention.

Ice nucleation active bacteria metabolites as antibiofilm agent to control Aeromonas hydrophila and Streptococcus agalactiae infections in Aquaculture

ObjectivesThe aim of this study was to quantify and identify metabolites of Ice Nucleation Active (INA) bacteria as an anti-biofilm agent against biofilms of fish pathogens such as Aeromonas hydrophila and Streptococcus agalactiae.ResultsIce nucleation active bacteria, which have the ability to catalyze ice nucleation, isolated from rainwater in previous studies, were used. All INA isolates were tested in several assays, including the antimicrobial test, which uses streptomycin as the positive control and none of the isolates were found positive in the antimicrobial test. As for the quorum quenching assay, it was found that four out of ten isolates were able to disturb the communication system in Chromobacterium violaceum wild type, which was used as the indicator bacteria. On the next assay, all ten isolates were tested for Biofilm Inhibition and Destruction and showed anti-biofilm activity with the highest percentage inhibition of 33.49% by isolate A40 against A. hydrophila and 77.26% by isolate A19 against S. agalactiae. C1 performed the highest destruction against A. hydrophila and S. agalactiae, with percentages of 32.11% and 51.88%, respectively. As for the GC-MS analysis, supernatants of INA bacteria contain bioactive compounds such as sarcosine and fatty acids, which are known to have antibiofilm activity against several biofilm-forming bacteria. Through 16s rRNA sequencing, identified bacteria are from the Pantoea, Enterobacter, and Acinetobacter genera. As for the conclusion, ice nucleation active bacteria metabolites tested showed positive results against pathogenic bacteria Aeromonas hydrophila and Streptococcus agalactiae in destructing and inhibiting biofilm growth.

Effect of gallium nitrate on the antibacterial activity of vancomycin in methicillin-sensitive and resistant Staphylococcus aureus.

The extension of multidrug-resistant strains of Staphylococcus aureus (S. aureus) is one of the main health challenges in the world, which requires serious solutions to deal with it. Combination therapies using conventional antibiotics and new antibacterial compounds that target different bacterial pathways are effective methods against resistant bacterial infections. Gallium is an iron-like metal that competes with iron for uptake into bacteria and has the potential to disrupt iron-dependent vital processes in bacteria. In this study, we explored the antibacterial effects of gallium nitrate (Ga(NO3)3) and vancomycin alone and in combination with each other on methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) using microdilution assay and checkerboard test, respectively. Then, their effect on the formation and destruction of biofilms was investigated. Finally, the amount of ROS production in the presence of these two compounds in bacteria was evaluated. The results indicated that the vancomycin/ Ga(NO3)3 combination reduced the MIC of vancomycin in the MRSA strain and had an additive effect on it. Vancomycin plus Ga(NO3)3 reduced the formation of biofilms and increased the destruction of biofilms formed in both strains, especially in the MRSA strain. ROS production was also higher in the combination of vancomycin with Ga(NO3)3 compared to vancomycin alone, especially in MRSA. Therefore, our results showed that Ga(NO3)3 enhances the antibacterial activity of vancomycin and this combination therapy can be considered as a new strategy for the treatment of MRSA infections.

Interfacially self-assembled Fe2O3 nanoparticles decorated kaolinite for high performance anti-bacterial and anti-cancerous agents

Nano-engineering of naturally occurring layered materials incorporates enhanced inherent properties for bionanotechnology. Here, kaolinite was treated with a concentrated aqueous ferrous sulfate solution at 100 °C for 1 h for surface modification. Therefore, interfacially self-assembled nanostructure of ferric oxide (Fe2O3) decorated kaolinite composites (FDKC) was fabricated from cationically (Fe2+) modified kaolinite (CMK) after calcinations at 680 °C. Characterized nanocomposites by ATR-IR, EDS, XRD and SEM were tested for antimicrobial activity and antibiofilm activity against Gram negative bacteria Escherichia coli (E. coli), Klebsiella spp (K. spp) and Salmonella typhi (S typhi), as well as Gram positive Staphylococcus aureus, while cytotoxic activity was observed against HeLa cell. CMK and FDKC showed significantly higher antimicrobial activity and biofilm destruction ability than virgin kaolinite (p < 0.05). Besides, FDKC showed the highest anticancer activity in HeLa cell at moderate concentration. The synergistic effect of nanocomposites would offer the modulation of enhanced electronic and physical properties from a simple technology to improve inherent antimicrobial activity and cell toxicity of kaolinite for targeted assay.

Bacterial biofilm formation in seafood: Mechanisms and inhibition through novel non‐thermal techniques

AbstractSeafoods are susceptible to microbial contamination due to their high moisture, nutrient contents and neutral pH. Among various microorganisms, biofilm‐forming bacteria pose a severe threat to the seafood supply chain as well as consumer health. Bacterial biofilm formation in seafood is primarily caused by Aeromonas hydrophila, Vibrio cholerae, V. vulnificus, V. parahaemolyticus, Salmonella spp., and Listeria monocytogenes. Biofilm formation is an important protective mechanism of microorganisms causing spoilage of seafood and disease threats to consumers. The attachment of microbes on the surface of seafood followed by the growth and proliferation of bacterial cells leads to the production of exopolymer compounds and the formation of biofilm. This biofilm is difficult to destroy or inhibit through conventional prevention/destruction techniques. The occurrence of bacterial strains/biofilms with more resistance to different preventive strategies is a big challenge for the seafood processing industry. This review covers the mechanisms of biofilm formation by bacteria and various non‐thermal processing approaches to prevent microbial contamination and biofilm formation in seafood products. The aforementioned non‐thermal processing techniques for the destruction of biofilm and quality control of seafood products include cold plasma treatment, irradiation, pulsed electric field technology, hydrostatic pressure processing, photosensitisation, natural bioactive compounds and so on. All these techniques effectively inhibit the bacterial biofilm and microbial growth without altering sensorial properties. However, further research validation and applications at the industry level are still required.

Silibinin-loaded chitosan-capped silver nanoparticles exhibit potent antimicrobial, antibiofilm, and anti-inflammatory activity against drug-resistant nosocomial pathogens

Nanoparticles capped with natural products can be a cost-effective alternative to treat drug-resistant nosocomial infections. Therefore, silibinin-loaded chitosan-capped silver nanoparticles (S-C@AgNPs) were synthesized to evaluate their antimicrobial and anti-inflammatory potential. The S-C@AgNPs plasmon peak was found at 430 nm and had a particle size distribution of about 130 nm with an average hydrodynamic diameter of 101.37 nm. The Scanning Electron Microscopy images showed the presence of sphere-shaped homogeneous nanoparticles. The Fourier Transform Infrared Spectroscopy analysis confirmed the loading of silibinin and chitosan on the AgNPs surface. The minimum inhibitory concentration of the S-C@AgNPs was reported between 3.12 μg/ml to 12.5 μg/ml and a minimum bactericidal concentration between 6.25 μg/ml to 25 μg/ml against drug-resistant nosocomial pathogens. Moreover, concentration-dependent significant inhibition of the biofilm formation was reported against P. aeruginosa (70.21%) and K. pneumoniae (71.02%) at 30 μg/ml, and the highest destruction of preformed biofilm was observed at 100 μg/ml against P. aeruginosa (89.74%) and K. pneumoniae (77.65%) as compared to individual bacterial control. Additionally, the fluorescence live/dead assay for bacterial biofilm confirmed that 100 µg/ml effectively inhibits the biofilm formed by these pathogens. S-C@AgNPs also showed anti-inflammatory activity, which is evident by the significant decrease in the proinflammatory cytokines and chemokines level in THP1 cells treated with LPS. This study concluded that S-C@AgNPs have potent antimicrobial, antibiofilm, and anti-inflammatory properties and could be a potential option for treating drug resistant nosocomial infections.

Antimicrobial and antibiofilm activities of Brazilian organic honey against oral microorganisms.

To evaluate the antimicrobial activity of Brazilian honeys against oral microorganisms. Organic honeys (OH-1 to OH-8) were diluted (%-w/v) and sterilized by filtration. Antimicrobial activity was defined by determining MIC and CBM against oral Streptococcus. The component responsible for the antimicrobial action was defined by a catalase assay. Antibiofilm activity was evaluated against the monospecies biofilm of Streptococcus mutans(ATCC 700610). OHs showed antimicrobial activity principally OH-1, OH-2, OH-3, and OH-7 with MIC values ​​ranging between 10 and 25%. The mechanism of action occurs mainly by hydrogen peroxide produced by honey enzymes. OH-1, OH-2, and OH-7 showed total biofilm destruction at low concentrations. Brazilian honeys have promising antimicrobial and antibiofilm activity with the potential to control oral microbiota.

Antibacterial effect of novel dental resin composites containing rod-like zinc oxide

Abstract Dental resin composite materials are widely used as dental fillings; however, the accumulation of microbes and the resulting secondary caries often leads to filling failure. ZnO, an inorganic antibacterial material, exhibits effective antibacterial properties and is considered safe for use. In this study, rod-like ZnO was prepared by using the atmospheric-pressure hydrothermal method, and its microstructure and antibacterial effects on Streptococcus mutans were studied. Subsequently, we created modified resins by incorporating rod-like ZnO at varying mass fractions and analyzed their morphological characteristics and elemental distributions. The antibacterial effectiveness, biocompatibility, and mechanical properties of these materials were examined using in vitro experiments. The results indicated that the rod-like ZnO exhibited a complete hexagonal wurtzite structure, with columnar dimensions of approximately 2.5 μm in length, 0.8 μm in diameter, and a lattice spacing of 0.2544 nm. The growth, biofilm formation, and biofilm destruction of S. mutans were significantly inhibited at 1/4, 1/2, 3/4, and 1 times the minimum inhibitory concentration. The rod-like modified resin, with mass fractions of 2.5, 5, and 7.5 wt%, exhibited evident inhibitory effects on S. mutans biofilm formation. These modified resins demonstrated no cytotoxicity toward HGF-1 cells and exhibited enhanced compressive strength. Therefore, rod-like ZnO modified resin has promising potential for the treatment of dental caries.

Improved electro-destruction of bacterial biofilms by coating conductive surfaces with polymers

The formation of biofilm involves cell aggregation and adherence, enveloped by a self-produced extracellular matrix. In the medical domain, biofilm-associated infections pose significant challenges, especially concerning implants. This investigation focuses on enhancing electromediated bacterial biofilm eradication through polymer coatings on the anode. These coatings catalyze reactive oxygen species (ROS) generation or convert hydrophobic coatings to bactericidal hydrophilic polycations, detaching the biofilms that are predominantly polyanionic. The first approach employs a metallized polytetrathienylporphyrin layer with ROS catalytic capability, while the second involves an insoluble hydrophobic polyamide, which, upon oxidation, transforms into a bactericidal hydrolytically degradable polycation. Both approaches show promising efficacy in augmenting electromediated Staphylococcus aureus biofilm destruction.

Lucilia sericata Maggot Extract: A Promising Tool against Biofilms of Antimicrobial Resistant Strains of Staphylococcus aureus and Pseudomonas aeruginosa

Background: This study explores the impact of Lucilia sericata maggots on the development and eradication of biofilms created by the pathogenic bacteria, Staphylococcus aureus and Pseudomonas aeruginosa. Methods: We assessed the influence of Lucilia sericata maggot extract on the viability of planktonic bacteria, the formation and disruption of biofilms, bacterial metabolic activity. Also the effect of simultaneous ES-antibiotic treatment in biofilm elimination was investigated. Additionally, the expression levels of genes associated with biofilm formation, namely LasI, psLA, agrA, and icaD was studied. Results: The results showed that ES can reduce the viability of planktonic S. aureus, significantly. Furthermore, ES of larvae fed on S. aureus-infected meat displayed the most substantial inhibition of biofilm formation (62.11% and 75.04% inhibition for S. aureus and P. aeruginosa, respectively). A similar trend was observed in biofilm destruction, with values of 56.67% and 68.50% inhibition for S. aureus and P. aeruginosa, respectively. The simultaneous application of ES of larvae that fed on S. aureus-infected meat and the minimum inhibitory concentration (MIC) of gentamicin resulted in 100% inhibition of biofilm formation by S. aureus. Notably, the group treated with ES of larvae fed on S. aureus-infected meat exhibited the most significant reduction in metabolic activity, with values of 95.03% and 68.25% for S. aureus and P. aeruginosa, respectively. The expression of LAsI and pslA genes in P. aeruginosa and the expression of agrA and icaD genes in S. aureus has decreased Conclusion: The findings of this study demonstrate that maggot extract has not only impacted the formation, but also eliminated the biofilms of S. aureus and P. aeruginosa.