Higher Antibacterial Effect Research Articles

Multifunctional Surface Modification of PDMS for Antibacterial Contact Killing and Drug-Delivery of Polar, Nonpolar, and Amphiphilic Drugs.

Medical device-associated infections pose major clinical challenges that emphasize the need for improved anti-infective biomaterials. Polydimethylsiloxane (PDMS), a frequently used elastomeric biomaterial in medical devices, is inherently prone to bacterial attachment and associated infection formation. Here, PDMS surface modification strategy is presented consisting of a cross-linked lyotropic liquid crystal hydrogel microparticle coating with antibacterial functionality. The microparticle coating composed of cross-linked triblock copolymers (diacrylated Pluronic F127) was deposited on PDMS by physical immobilization via interpenetrating polymer network formation. The formed coating served as a substrate for covalent immobilization of a potent antimicrobial peptide (AMP), RRPRPRPRPWWWW-NH2, yielding high contact-killing antibacterial effect against Staphylococcus epidermidis and Staphylococcus aureus. Additionally, the coating was assessed for its ability to selectively host polar, amphiphilic, and nonpolar drugs, resulting in sustained release profiles. The results of this study put forward a versatile PDMS modification strategy for both contact-killing antibacterial surface properties and drug-delivery capabilities, offering a solution for medical device-associated infection prevention.

Cymbopogon martinii essential oil nanoemulsions: Physico-chemical characterization, antibacterial and antibiofilm potential against Enterococcus faecalis

Cymbopogon martinii is an aromatic crop cultivated for the production of its essential oil (EO) which has different applications. Bearing in mind that C. martinii EO (CMEO) has already been proved for high antibacterial potential the aim of this study was to formulate stable CMEO nanoemulsions, being capable to combat Enterococcus faecalis biofilm, especially within infected tooth’s root canal. Ten emulsions with variable CMEO content (2.5–10 % v/v) and Tween 80 (T80, 2.5–15 % v/v) were formulated (designated as E CMEO:T80 ) and screened for volume-weighted mean diameter (D4,3) and stability, using dynamic light scattering measurements. Chemical composition of stable nanoemulsions was monitored by UV–VIS and FTIR, while their antibacterial activity was estimated in microdilution assay. Antibiofilm properties of selected nanoemulsions were tested in vitro (cristal violet assay) and ex vivo (within root canals of the extracted teeth). Results showed that formulations containing 10 % of T80 and CMEO volume ≤ 6 %, as well as those having constant 2.5 % of CMEO and variable T80 volume (≤ 10%), namely E 2.5:2.5 , E 2.5:5, E 2.5:7.5, E 2.5:10, E 4:10 , and E 6:10 , were stable and nanosized (D4,3 <100 nm). FTIR and UV–VIS analyses confirmed successful encapsulation of the CMEO by T80 and showed that nanoemulsification did not affect CMEO composition. Evaluation of antibacterial potential showed that the most efficient were E 6:10 , E 2.5:2.5 and E 4:10 (MIC values 0.37–1.97 mg mL −1 ). Analysis of dependency of determined MICs on mean diameter and CMEO volume showed that antibacterial potential increased with both parameters. E 6:10 , E 2.5:2.5 and E 4:10 also reduced in vitro biofilm (inhibitory range 17.6–58.4 %), as well as intracanal biofilm (reduction ~2Log CFU) . Presented results suggest E 6:10, E 4:10 and E 2.5:2.5 as the good candidates for further research. • Emulsions with different ratio of C. martini oil and Tween 80 were prepared. • Characterization of the nanoemulsions showed successful oil encapsulation. • Nanoemulsions E 6:10 , E 2.5:2.5 , E 4:10 proved high antibacterial effect. • Nanoemulsions E 6:10 , E 2.5:2.5 and E 4:10 reduced ex vivo intracanal biofilm. • Nanoemulsification improved antibiofilm potential of the C. martini oil.

Antibiotic delivery from bone-targeted mesoporous silica nanoparticles for the treatment of osteomyelitis caused by methicillin-resistant Staphylococcus aureus

Osteomyelitis is a hard-to-treat infection of the bone and bone marrow that is mainly caused by Staphylococcus aureus, with an increasing incidence of methicillin-resistant S. aureus (MRSA). Owing to the aggressiveness of these bacteria in colonizing and destroying the bone, systemic antibiotic treatments fail to eradicate the infection. Instead, it normally entails surgery to remove the dead or infected bone. In this work, we report bone-targeted mesoporous silica nanoparticles for the treatment of osteomyelitis. The nanoparticles have been engineered with a functional gelatine/colistin coating able to hamper premature release from the mesopores while effectively disaggregating the bacterial biofilm. Because antibiotic resistance is a global emergency, we have designed two sets of identical nanoparticles, carrying each of them a clinically relevant antibiotic, that have demonstrated to have synergistic effect. The bone-targeted nanoparticles have been thoroughly evaluated in vitro and in vivo, obtaining a notable reduction of the amount of bacteria in the bone in just 24 h after only one dose, and paving the way for localized, nanoparticle-mediated treatment of MRSA-caused osteomyelitis. Statement of significanceIn this work, we propose the use of bone-targeted mesoporous silica nanoparticles to address S. aureus-caused osteomyelitis that render synergistic therapeutic effect via multidrug delivery. Because the bacterial biofilm is responsible for an aggressive surgical approach and prolonged antibiotic treatment, the nanoparticles have been functionalized with a functional coating able to both disaggregate the biofilm, hamper premature antibiotic release and protect the intact bone. These engineered nanoparticles are able to effectively target bone tissue both in vitro and in vivo, showing high biocompatibility and elevated antibacterial effect.

Screening of four accelerated synthesized techniques in green fabrication of ZnO nanoparticles using Willow leaf extract

Abstract Using hydro-alcoholic extract of Willow leaf, zinc oxide nanoparticles (ZnO NPs) were synthesized via four accelerated different heating methods namely, Bain-Marie heating (40 °C for 2 h), Conventional heating with stirrer (80 °C for 2 h), hydrothermal autoclave (1.5 atm and 121 °C for 15 min) and microwave irradiation (800 W and 160 °C for 3 min). Calcination process was finally completed on the obtained colloidal solutions in a furnace (350 °C for 2 h). The characteristics of the resulted ZnO NPs including particle size, grain size, crystallinity, specific surface area, morphology, photocatalytic, antioxidant bactericidal activities were estimated using X-ray diffractometry, scanning electron microscopy and Ultraviolet-visible spectroscopy techniques. Attained results indicated that among four different utilized synthetic methods, the fabricated ZnO NPs via Bain-Marie heating, had desired physico-chemical characteristics and bactericidal effect including small particle size (70 nm), high specific area (284 m2/gr), antioxidant activity (28.5%), photocatalytic activity (degradation of 50% of Methylene Blue), and bactericidal effects against Escherichia coli (clear zone diameter of 1.4 ± 0.1 cm) and Staphylococcus aureus (1.3 ± 0.1 cm).

High reactivity and bactericidal effects of plasma‐activated mist from hydrogen peroxide solution

AbstractHydrogen peroxide solutions are often utilized in logistics sterilization by misting, although their sterilizing capacity is diminished. To meet the high‐efficient and long‐term sterilization requirements of logistics, the reactivity and bactericidal efficiency are improved with plasma‐activated H2O2 solutions mist (PAHM). PAHM promotes an approximately double increase in the concentration of reactive nitrogen species, four times increase in the O3 concentration, and 36.2 times increase in H2O2 compared with water mist activation. Escherichia coli and Staphylococcus aureus are selected as the model microorganisms to evaluate the bactericidal activity. Results show that PAHM can reduce the numbers of both bacteria by two orders of magnitude after 3 min of treatment, similar to inactivated H2O2 for 10 min of treatment.

Cross-linked lyotropic liquid crystal particles functionalized with antimicrobial peptides

Antimicrobial peptides (AMPs) are promising alternatives to traditional antibiotics for addressing bacterial infections – including life-threatening antibiotic resistant infections. AMPs have a broad spectrum of antimicrobial activity and show a low probability to induce resistance. However, the poor serum stability of AMPs has limited their usage in clinical treatment. To enable improved serum stability while maintaining high antibacterial effect of AMPs, this study describes a material wherein AMPs are covalently bonded to micro-sized particles of cross-linked lyotropic liquid crystals, formed by the self-assembly of the block copolymer Pluronic F-127. The liquid crystal particles were shown to have antibacterial effect corresponding to a 4 log reduction against Staphylococcus aureus. The particles were structurally and chemically analyzed by small angle X-ray scattering, Fourier transform infra-red spectroscopy and Raman spectroscopy, confirming that the liquid crystal structure was maintained within the particles with the AMPs covalently bonded. The bonding to the particles gave the AMPs improved stability in serum, as they retained almost all of the antibacterial potency for 2 days compared to free AMPs, which lost all of its antibacterial potency within a day. Furthermore, insight regarding mode of action was obtained by cryogenic transmission electron microscopy, which showed the antimicrobial particles interacting with the surface of bacteria.

Influence of silver content on microstructural, bactericidal, and cytotoxic behavior of TiAlVN (Ag) composite coatings deposited by magnetron sputtering

Titanium alloys are attractive for the manufacture of bone implants, due to their high biocompatibility, chemical stability, and adequate resistance/specific weight ratio. However, its ability to reject the adhesion of bacteria and the formation of biofilms is very limited. Further, their low hardness and tribological resistance limits the scope of their application, so it is common to apply surface treatments to improve this property. In this work, the deposition of TiAlVN(Ag)x nanocomposite coatings using the direct current magnetron sputtering technique was proposed, with the aim of giving the coated substrates a significant bactericidal effect without significantly affecting their hardness and cell viability. The coatings were deposited from two independent targets of Ti6Al4V alloy and silver faced at 180° to each other. The atomic percent contents of silver in the compound were 8.1%; 10.6%; 12.6% and 14%, which was adjusted by varying the power applied to the silver target between 0 and 100W while maintaining the power supplied to the titanium alloy target constant at 2000W. The microstructural properties, elemental chemical composition, phase composition and surface topography of the deposited coatings were evaluated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and atomic force microscopy (AFM), respectively. The bactericidal effect of the composite coatings was assessed by evaluating the inhibition (JIS Z-2801 standard) and adhesion of the Pseudomonas aeruginosa bacteria, while the cell viability was assessed using human osteoblasts of the Saos-2 cell line, following the MTT method (colorimetric assay for assessing cell metabolic activity). All the deposited coatings showed a high bactericidal effect against P. aeruginosa, exhibiting inhibition greater than 99.99% and avoiding surface adherence by 100%. The TiAlVN(Ag) samples with 8.1 at% and 10.6 at% silver, and which presented the best ratio of mechanical and tribological properties (not shown here), exhibited high biocompatibility and adherence of the osteoblasts to the coated substrates.

Comparative Analysis of Novel Iron Oxide Nanoparticles Synthesized by Different Approaches with Evaluation of Their Antibacterial Activities

In this study, stable novel iron oxide nanoparticles (IO-NPs) were synthesized via chemical and green methods. In the chemical method, p-aminobenzoic acid (AB), diacetyl monoxime (DIA), and adenosine 5-monophosphate disodium (AD) were used as stabilized ligands, whereas the extract of Teucrium apollinis was used in the green synthesis method. The effect of these stabilized ligands on the size, stability, and antibacterial activity of IO-NPs was carried out. The synthesized IO-NPs were characterized using UV-Visible absorption spectroscopy (UV-Vis), dynamic light scattering (DLS), transmission electron microscopy (TEM), and attenuated Fourier transform infrared (ATR-FTIR). IO-NPs offered spherical shapes with small sizes (5 nm, 6 nm, 8 nm, and 34 nm) for IO-NPs functionalized by DIA, AD, AB, and Teucrium apollinis, respectively. This study shows a relationship between the type of NPs and Pseudomonas aeruginosa growth. The IO-NP functionalized by plant extract has a higher antibacterial effect than IO-NPs chemically synthesized. Because it has more infinity toward bacteria cells than other NP, it has a high ability to penetrate the membrane of bacterial cells. The use of Teucrium apollinis extract could be an eco-friendly way to synthesize IO-NP that offers a novel and potential alternative to chemically synthesized IO-NP.

Breaching Bacterial Biofilm Barriers: Efficient Combinatorial Theranostics for Multidrug-Resistant Bacterial Biofilms with a Novel Penetration-Enhanced AIEgen Probe

The formation of microbial biofilms is acknowledged as a major virulence factor in a range of persistent local infections. Failures to remove biofilms with antibiotics foster the emergence of antibiotic-resistant bacteria and result in chronic infections. As a result, the construction of effective biofilm-inhibiting and biofilm-eradicating chemicals is urgently required. Herein, we designed a water-soluble probe APDIS for membrane-active fluorescence and broad-spectrum antimicrobial actions, particularly against methicillin-resistant Staphylococcus aureus (MRSA), which shows multidrug resistance. In vitro and in vivo experiments demonstrate its high antibacterial effects comparable to vancomycin. Furthermore, it inhibits biofilm formation by effectively killing planktonic bacteria at low inhibitory concentrations, without toxicity to mammalian cells. More importantly, this probe can efficiently penetrate through biofilm barriers and exterminate bacteria that are enclosed within biofilms and startle existing biofilms. In the mouse model of implant-related biofilm infections, this probe exhibits strong antibiofilm activity against MRSA biofilms, thus providing a novel theranostic strategy to disrupt biofilms in vivo effectively. Our results indicate that this probe has the potential to be used for the development of a combinatorial theranostic platform with synergistic enhanced effects for the treatment of multidrug-resistant bacterial infections and antibiofilm medications.

Bazı Bitki Ekstrelerinin Cerrahi Maske Üretiminde Kullanılabilirliğinin Antibakteriyel Açıdan Araştırılması

Bu çalışmada, nar (Punica granatum L.) kabuğu, pıtrak (Xanthium strumarium L.) bitkisinin&#x0D; büyük ve küçük meyveleri, alman papatyası (Anthemis nobilis L.) çiçeği, mayıs papatyası&#x0D; (Matricaria chamomilla L.) çiçeği, kırmızı biber (Capsicum annuum L.) tohumu, yeşil biber&#x0D; (Capsicum annuum L.) tohumu ekstrelerinin ve gümüş suyunun antibakteriyel etkisi araştırılmıştır.&#x0D; Çalışmanın sonunda pıtrak (Xanthium strumarium L.) bitkisinde, Escherichia coli (ATCC 25922)&#x0D; üzerinde kontrole göre %166,6 oranla, Staphylococcus aureus (ATCC 29213) üzerinde ise %70&#x0D; oranla daha fazla antibakteriyel zon tespit edilmiştir. Ağız florasından yayılan bakterilerde ise&#x0D; en yüksek antibakteriyel etki kontrole göre %166,6 oranla daha fazla zon tespit edilen pıtrak&#x0D; (Xanthium strumarium L.) bitkisinde ve gümüş suyunda görülmüştür. Bitki ekstreleri içeren&#x0D; cerrahi maske örneklerinin antibakteriyel etkisi incelenmiş olup, pıtrak (Xanthium strumarium L.)&#x0D; ekstresi içeren örneğin kontrole göre %39 daha az bakteri üremesi sağladığı tespit edilmiştir.

Bacterial Surface Disturbances Affecting Cell Function during Exposure to Three-Compound Nanocomposites Based on Graphene Materials.

Combating pathogenic microorganisms in an era of ever-increasing drug resistance is crucial. The aim of the study was to evaluate the antibacterial mechanism of three-compound nanocomposites that were based on graphene materials. To determine the nanomaterials’ physicochemical properties, an analysis of the mean hydrodynamic diameter and zeta potential, transmission electron microscope (TEM) visualization and an FT-IR analysis were performed. The nanocomposites’ activity toward bacteria species was defined by viability, colony forming units, conductivity and surface charge, cell wall integrity, ATP concentration, and intracellular pH. To ensure the safe usage of nanocomposites, the presence of cytokines was also analyzed. Both the graphene and graphene oxide (GO) nanocomposites exhibited a high antibacterial effect toward all bacteria species (Enterobacter cloacae, Listeria monocytogenes, Salmonella enterica, and Staphylococcus aureus), as well as exceeded values obtained from exposure to single nanoparticles. Nanocomposites caused the biggest membrane damage, along with ATP depletion. Nanocomposites that were based on GO resulted in lower toxicity to the cell line. In view of the many aspects that must be considered when investigating such complex structures as are three-component nanocomposites, studies of their mechanism of action are crucial to their potential antibacterial use.

Cytotoxicity and antibacterial effects of silver doped zinc oxide nanoparticles prepared using fruit extract of Capsicum Chinense

Phyto-mediated nanoparticles (NPs) have attracted great attention in recent times due to their unique properties such as high biocompatibility, eco-friendliness, and cost-effectiveness. In this study, silver- zinc oxide nanoparticles (Ag/ZnO-NPs) were prepared using the fruit extract of Capsicum Chinense. The results obtained from both structural, and optical characterization of the nanoparticles confirmed the purity of the composites and their high crystallinity. The nanoparticles exhibited two absorption peaks at 376 and 258 nm with a bang gap energy of 3.53 eV, and the nanoparticulate size of the materials exhibited antibacterial and cytotoxic activities. The Ag/ZnO-NPs exhibited better proliferative activity against HEK 293 cells than HeLa cells. The antibacterial study showed that both the pristine and the composite nanoparticles (ZnO and Ag/ZnO-NPs) have high bactericidal effect on all tested bacterial pathogens, with Ag/ZnO-NPs displaying better antibacterial activity. Cytotoxicity studies showed a dose-dependent proliferative relationship between Ag/ZnO-NPs and tested cancer cells (HEK 293 and HeLa). Antibacterial results showed significant zones of bactericidal inhibition for all tested bacterial pathogens using the biosynthesized ZnO and Ag/ZnO-NPs. These findings demonstrated two-fold applications of biosynthesized Ag/ZnO-NPs, as anticancer and antibacterial agents.

Seasonal changes in rosemary species: A chemotaxonomic assessment of two varieties based on essential oil compounds, antioxidant and antibacterial activities.

Rosemary (Rosmarinus officinalis L.) is a popular herb in cooking, traditional healing, and aromatherapy. This study was conducted to evaluate the effects of meteorological conditions plant growth stage and genetic factors on the yield, quantitative and qualitative composition, on the antioxidant and antimicrobial activities of rosemary essential oil from two Tunisian locations (El Fahs and Matmata) during two successive years. The composition of the essential oils obtained by hydrodistilation from rosemary plants were carried out annually using GC and GC/MS. Results showed the the main constituents were camphor (18.2–28.1%), 1,8-cineole (6.4–18.0%), α-pinene (9.7–13.5%), borneol (4.4–9.5%), and camphene (5.1–8.7%). The principal component and heatmapper analyses showed group segregation of the two studied varities based on major essential oil compounds. Additionally, in vitro antimicrobial and antioxidant activities showed that rosemary essential oils had an important ability in scavenging DPPH, as well as a higher bactericidal effect. The seasonal variation, growth stage and genetic pools seemed to be a factors of significant variation of the composition, antimicrobial and the antioxidant activities of the rosemary essential oils. These finding would be taken to use the chemotaxonomy tools to develop a program for Rosmary protection conservation and identification based on essential oil composition.

Antibacterial effects and cellular mechanisms of iron oxide magnetic nanoparticles coated by piroctone olamine against some cariogenic bacteria

BackgroundThe present study aims to study antibacterial effects and cellular mechanisms of iron oxide magnetic nanoparticles loaded with piroctone olamine (Fe3O4@PO NPs) against some cariogenic bacteria (Streptococcus mutans and Actinomyces viscosus). MethodsNanoparticles was synthesized by the coprecipitation method. Antibacterial effects of Fe3O4@PO NPs were performed by calculating the minimum inhibitory concentration (MIC). We also evaluated the level of reactive oxygen species (ROS) and protein leakage to assess whether antibacterial effects may be dependent on these mechanisms. ResultsThe results demonstrated that PO showed the lowest antibacterial effect compared to other drugs tested with MICs values of 53.33 and 64 μg/ml for S. mutans and A. viscosus, respectively. In contrast, the highest antibacterial effect was related to Fe3O4@PONPs with MICs values of 2.66 and 3.33 μg/ml for S. mutans and A. viscosus, respectively. Fe3O4@PONPs, Fe3O4MNP, and PO markedly increased (p < 0.001) ROS production and protein leakage of tested bacteria at ≥¼ MIC, ≥1/3 MIC, and ½ MIC, respectively. ConclusionThe findings of the present survey revealed the promising antibacterial effects of Fe3O4@PONP against some cariogenic bacteria; whereas it triggered the ROS production and protein leakage as the possible antibacterial mode of action of anti-infective agents. However, additional surveys are necessary to elucidate the accurate mechanisms of these nanoparticles.

Surface characteristics and bacterial adhesion of endodontic cements

ObjectivesTo investigate the effect of inclusion of silver nano-particles (SNP) or bioactive glass (BG) on the surface characteristics and bacterial adhesion of prototype tricalcium silicate (TCS)–based cements alongside two commercial cements, under different aging periods and exposure conditions.Materials and methodsA basic formulation of radio-opacified TCS without (TZ-base) and with additions of SNP (0.5, 1, or 2 mg/ml) or BG (10 or 20%) was used. Biodentine and intermediate restorative material (IRM) served as reference materials. Material disks were immersed in ultrapure water or fetal bovine serum (FBS) for 1, 7, or 28 days. Surface roughness (n = 3), microhardness (n = 9), and wettability (n = 6) were analyzed by standard procedures. Adhesion of Enterococcus faecalis was assessed by fluorescence microscopy (n = 5). Data from these assays were evaluated for normality and comparisons among groups were conducted with statistical procedures (p < 0.05 for significance).ResultsThe surface morphology of SNP- and BG-containing cements had higher roughness values than TZ-base after 28 days (p < 0.05). No differences in microhardness were observed among prototype cements (p > 0.05). Biodentine presented smooth surface characteristics and the highest hardness values (p < 0.05). The FBS-immersion resulted in surface reactions in prototype materials and Biodentine, depicted with scanning electron microscopy. All 1- and 7-day prototype cements showed negligible bacterial adhesion, while in Biodentine and IRM, noticeable E. faecalis adherence was observed from day 1 (p < 0.05).ConclusionsIncorporation of SNP or BG did not improve the antibacterial effect of the experimental cement; all 28-day aged materials failed to inhibit bacterial adherence. The measured physical parameters did not appear to be related to the degree of bacterial adhesion. Exposure of TCS-based cements in FBS resulted in surface reactions, which did not affect bacterial adhesion.Clinical relevanceChanges in the surface characteristics of prototype TCS-based cements by inclusion of SNP and BG or exposure to different environments did not affect bacterial adhesion. All experimental materials showed inferior physical properties and higher antibacterial effect than Biodentine.

Phytochemical Analysis and Antibacterial Potential of Tabon-tabon (Atuna racemosa Raf) Fruit Extract against E. Coli BIOTECH 1634

This study aimed to examine the phytochemical levels of crude “tabon-tabon” (Atuna racemosa Raf.) fruit extracts subjected to air-drying, oven-drying, and freeze-drying. It also sought to validate the claims of previous literature on the fruit’s antimicrobial properties by using its aqueous extracts as an antibacterial wash for green ice leaf lettuce. Phytochemical analysis revealed significantly higher (p &lt; 0.05) levels of alkaloids and tannins compared to coumarins, saponins, and terpenoids. The highest alkaloid content (16.25 ± 1%) was obtained using oven- drying, whereas the highest tannin content was obtained using freeze-drying (14.14 ± 1.13%). In vivo antibacterial assay against Escherichia coli was performed to test the aqueous extracts alongside 200 ppm chlorine solution and water for comparison. Artificially-inoculated lettuce samples were individually soaked in 15-mL solution at 2- and 5-min contact times. Bacterial load was determined at a 2-d interval for a period of 8 d. Results of the microbiological analysis showed no significant interaction in the soaking time used. However, the treatments were independently found to have significant effects on Days 0, 4, and 6. The highest antibacterial effect in green ice lettuce was exhibited up to Day 6.

Antimicrobial modification of polypropylene films by photograft and layered double hydroxides assembly

Providing antimicrobial (AM) properties to polypropylene (PP) films is an appealing strategy for food packaging and biomedical areas. In this study, PP-based platforms with AM activity were obtained by the incorporation of layered double hydroxides (LDH) nanoparticles, intercalated with antimicrobial drugs (AMD), either nalidixate (Nal−) or benzoate (Bz−), to polyacrylate (PAA)-photografted PP films (PP-g-PAA/LDH-AMD). The assembly mechanism was explored, and the composition, morphological and interfacial properties of the obtained platforms were determined. Finally, the AM activity was assayed against Staphylococcus aureus and Escherichia coli strains. LDH-AMD were successfully incorporated to the platforms by electrostatic interactions with the carboxylate groups of the photografted PAA chains and they were mainly located in the outer region of the PAA layer. This incorporation was first produced at grooves and pits of this surface layer, and then spread by aggregation of the incoming LDH-AMD particles, which increased the surface roughness of PP-g-PAA/LDH-AMD platforms. These showed significant AM activity due to their roughness, the high surface AMD concentration and the positive charge of LDH-AMD particles. Thus, Nal-incorporating platforms presented a high bactericidal effect on the proliferation of both bacterial strains. On the other hand, Bz-loaded platform slightly delayed the bacterial growth of S. aureus.

In-Vitro antibacterial activity of glass ionomer cements containing silver nanoparticles synthesized from leaf extract of Mentha piperita

Purpose: The aim of this study was to evaluate the antibacterial activity of glass ionomer cement incorporated with silver nanoparticles (AgNPs) synthetized using mint leaf extract (Mentha piperita, M. piperita) on some oral cavity bacteria.Materials and methods: In the present study, M. piperita leaf extract was used for the synthesis of AgNPs. A total of 60 glass ionomer cement (GIC) disk-shaped specimens were prepared and divided into two groups: conventional GIC (C-GIC), and glass ionomer cement with 2 wt% AgNPs (GIC-AGNPs). The antibacterial activity of the GIC specimens in comparison with Ampicillin disk (10 µg/ml) was investigated against Streptococcus mutans, Enterococcus faecalis, Lactobacillus acidophilus, Lactobacillus casei, and Streptococcus aureus by measuring the diameter of growth inhibition zones.Results: C-GIC specimens failed to show any antibacterial effect against the studied bacteria. However, the GIC-AgNPs had relatively significant antibacterial effects on S. mutans, L. acidophilus, L. casei and S. aureus. The highest antibacterial effect of GIC-AgNPs specimens was reported against L. acidophilus (P &lt;0.001). GIC-AgNPs had no antibacterial effect on E. faecalis.Conclusion: Glass ionomer cement incorporated with AgNPs synthetized using M. piperita showed a promising antibacterial effect against oral cariogenic pathogens.

An in vitro comparison of antimicrobial efficacy and cytotoxicity between povidone-iodine and chlorhexidine for treating clinical endometritis in dairy cows.

This study aimed to assess the in vitro antimicrobial effects of chlorhexidine (CHX) and povidone-iodine (PI) on clinical isolates of Escherichia coli (E. coli) and Trueperella pyogenes (T. pyogenes) from the vaginal discharge of dairy cows, as well as to compare the cytotoxicity effects of CHX and PI on bovine endometrial epithelial cells (BEnEpC). In Experiment 1, 12 E. coli and 10 T. pyogenes were isolated from the vaginal discharge of cows with a uterine infection. The MIC and MBC against CHX and PI were analyzed in vitro. In Experiment 2, the cytotoxicity effects of CHX and PI on BEnEpC were analyzed using a Viability/Cytotoxicity Kit, wound scratch healing assay, and the expression of pro-inflammatory cytokine genes (IL-6, IL-8, and TNF-α). In Experiment 1, the MIC and MBC values of CHX against E. coli were 0.0002% and 0.0002 to 0.00025%, respectively. The MIC and MBC values of PI were 1.25 to 2.5% and 1.25 to 5%, respectively. For T. pyogenes, the MIC and MBC values of CHX were 0.00002%. The MIC and MBC values of PI were 1.25%. In Experiment 2, the cell viability significantly decreased, and wound closures were significantly inhibited after treatment with ≥ 0.002% CHX and ≥ 0.025% PI. The expression of IL-6, IL-8, and TNF-α significantly increased after treatment with PI. Only IL-6 showed a significant increase after cells were treated with 0.00002% and 0.0002% CHX. The results suggested that both CHX and PI had high antibacterial effects. However, veterinarians and farmers should be aware of their cytotoxicity, which decrease viability of endometrial epithelial cells and inhibit wound healing in vitro.

Evaluation of Antibacterial Effect of Aqueous, Hydro- Alcoholic and Alcoholic Extracts of Morus nigra on Gram-Positive and Gram-Negative Bacteria

Background: Microbial resistance to antibiotics has led to serious efforts to discover novel drugs, which is why there is so much interest in the use of herbs. Therefore, the aim of this study was to investigate the antibacterial effect of aqueous, hydro-alcoholic, and alcoholic extracts of Morus nigra in comparison with some common antibiotics. Method: In this experimental study, the zone of inhibition, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the Morus nigra extracts against Staphylococcus epidermidis, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus mutans and Streptococcus pyogenes were determined using the disk diffusion and broth macro-dilution methods. Statistical analysis was performed using the ANOVA test by SPSS software. Results: The results of this study showed that all studied strains were sensitive to different extracts of Morus nigra. The highest antibacterial effect was related to the aqueous extract of Morus nigra, which created an inhibition zone with a diameter of 22.25 against Streptococcus mutans and Streptococcus pyogenes. The lowest inhibition zone (9 mm) was related to the alcoholic extract of Morus nigra against Pseudomonas aeruginosa. The MIC values of different extracts of Morus nigra against test bacteria varied from 0.78 to 3.12 mg/ml and MBC values were between 3.12 and 50 mg/mL. Conclusion: Based on the findings of this study, the aqueous extract of Morus nigra has shown strong bactericidal properties against all studied bacterial strains, which indicates its potential for therapeutic application.