Antibiofilm Formation Activity Research Articles

Purified L-glutaminase effects against multidrug-resistant Pseudomonas aeruginosa in experimental vaginosis model: An immunological and histopathological observation

The antimicrobial activity of crude and purified L-glutaminase (EC 3.5.1.2), obtained from Lactobacillus gasseri, was evaluated against multidrug-resistant Pseudomonas aeruginosa in the in vivo vaginosis condition. The L-glutaminase possessed significant antimicrobial and anti-biofilm formation activity against multi-drug resistance P. aeruginosa, which were confirmed in the BALBc rat vaginosis model, together with its effects on the immunological and histopathological aspects. The untreated animals showed heavy vaginitis, characterized by sub-epithelial edema and infiltration of mononuclear leukocytes, perivascular heavy inflammatory cells infiltration in the vaginal tissue, and moderate stromal edema. However, the L-glutaminase treatment exhibited no changes in vaginal tissue structure with normal appearance of the epithelium and lamina propria with marked repair of the vaginal section when compared with normal, uninfected, control group A. The immunomodulatory actions of the L-glutaminase were confirmed by observance of higher concentrations of tumor necrosis factor-γ (TNF-γ), and interleukin −12 (IL-12) in treated animals, while the interleukin-10 (IL-10) was higher in the infected, untreated animals' sera samples. Therefore, the L-glutaminase showed corrective and healing actions, which were observed through histopathological observations of the vaginal tissue. The investigations led to imply that L-glutaminase may have the potential to be an effective antimicrobial agent for preventing and inhibiting bacterial growth, as well as inhibiting the biofilm formation in the P. aeruginosa-originated vaginosis. The observations may be of promising value for future clinical use.

Drug delivery and antibiofilm efficacy of nano silver fluoride sustained release orthodontic elastomerics against Streptococcus mutans

We aimed to investigate the chemical and physical properties of nano silver fluoride sustained release orthodontic elastomerics (NSF-RE) and determine their antimicrobial and antibiofilm formation activities against Streptococcus mutans. Orthodontic elastomerics were dip-coated with NSF solution in ethyl cellulose (EC) and polyethylene glycol 6000 (PEG). The studied groups included NSF (no EC/PEG), NSF-E (EC), NSF-EP1 (EC:PEG, 4:1), and NSF-EP2 (EC:PEG, 2:1). The cumulative release of silver nanoparticles (AgNPs) and fluoride, along with the compatibility of the tensile force with orthodontic brackets, was evaluated. The antimicrobial activity was evaluated using an agar diffusion test. The inhibition of biofilm formation was evaluated using colony-forming units (CFUs), biofilm thickness, and the live/dead cell ratio. NSF-RE containing EC sustained the release of AgNPs and fluoride for > 7 days. Tensile forces were not significantly different among the groups. The inhibition zone was 2.64- and 1.31-fold larger with NSF-EP2 than that with NSF and NSF-E, respectively. NSF-EP2 was the most effective in inhibiting biofilm formation with significant reductions in CFUs, biofilm thickness, and live/dead cell ratio by 57, 86, and 96%, respectively, as compared to those in the control group. Overall, sustained release of AgNPs and fluoride by NSF-RE provides antimicrobial and antibiofilm effects against S. mutans.

Green synthesis of silver nanoparticles and evaluation of their effects on the Porphyromonas gingivalis bacterial biofilm formation.

This study aimed to evaluate the impact of silver nanoparticles (AgNPs) synthesized from propolis on the formation of Porphyromonas gingivalis biofilms. AgNPs were synthesized from propolis, and their inhibitory effect on P. gingivalis biofilm formation was assessed. Different concentrations of AgNPs (0.1%, 0.3%, and 0.5%) were tested to determine the dose-dependent antibacterial activity. The results of this study indicated that AgNPs exhibited an inhibitory effect on P. gingivalis biofilm formation. The antibacterial activity of AgNPs was dose-dependent, with concentrations of 0.1%, 0.3%, and 0.5% showing effectiveness. Notably, the concentration of 0.5% demonstrated the most significant anti-biofilm formation activity. The results of this study suggest that AgNPs synthesized from propolis have potential as an effective option for enhancing periodontal treatment outcomes. The inhibitory effect of AgNPs on P. gingivalis biofilm formation highlights their potential as alternative antimicrobial agents in the management of periodontal diseases.

Unveiling the antibacterial mechanism of resveratrol against Aeromonas hydrophila through proteomics analysis.

This investigation delves into elucidating the mechanism by which resveratrol (Res), a natural polyterpenoid renowned for its antimicrobial properties, exerts its effects on Aeromonas hydrophila, a ubiquitous waterborne pathogen. Our findings underscore the dose-dependent manifestation of resveratrol in exhibiting antibacterial and antibiofilm formation activities against A. hydrophila. Employing a Data-independent acquisition (DIA) based quantitative proteomics methodology, we systematically compared differentially expressed proteins in A. hydrophila subjected to varying concentrations of Res. Subsequent bioinformatics analyses revealed key proteins and pathways pivotal in resveratrol's antimicrobial action, encompassing oxidative stress, energy metabolism, and cell membrane integrity. Validation of the proteomics outcomes was meticulously conducted using the qPCR method at the mRNA level. Dynamic trend analysis unveiled alterations in biological processes, notably the correlation between the cell division-related protein ZapC and resveratrol content. Furthermore, scanning electron microscopy corroborated a significant elongation of A. hydrophila cells, affirming resveratrol's capability to inhibit cell division. In concert, resveratrol emerges as a participant in the cell membrane integrity pathway, biofilm formation, and potentially, the regulation of genes associated with cell division, resulting in morphological elongation. These revelations position resveratrol as a promising natural alternative to conventional antibiotics for treating A. hydrophila infections.

Targeting the Antifungal Activity of Carbon Dots against Candida albicans Biofilm Formation by Tailoring Their Surface Functional Groups.

Carbon dots (CDs) are an emerging class of carbon nanoparticles, which for their characteristics have found applications in many fields such as catalysis, materials and biomedicine. Within this context, the application of CDs as antibacterial agents has received much attention in very recent years, while their use as antifungal nanoparticles has been scarcely investigated. Here we report a systematic investigation of the surface functional groups of CDs to study their influence on these nanoparticles' against Candida albicans. Three classes of CDs have been synthesised and fully characterized. A thorough in vitro and in vivo biological screening against C. albicans was performed to test their antifungal, antiadhesion and antibiofilm formation activities. Moreover, the interaction with C. albicans cells was investigated by microscopic analysis. Our results evidence how the presence of a positively polarised surface results crucial for the internalization into COS-7 cells. Positively charged nanoparticles were also able to inhibit adhesion and biofilm formation, to interact with the cellular membrane of C. albicans, and to increase the survival of G. mellonella infected larvae after the injection with positive nanoparticles. The antifungal activity of CDs and their extremely low toxicity may represent a new strategy to combat infections sustained by C.albicans.

Identification of novel phenylalanine derivatives bearing a hydroxamic acid moiety as potent quorum sensing inhibitors.

Phenylalanine derivatives are a well-known small moiety responsible for controlling the virulence factors of several bacteria. Herein, for the first time, we report novel structures of phenylalanine derivatives bearing a hydroxamic acid moiety which were designed, synthesized, and evaluated for use as quorum sensing inhibitors. Biological results reveal that six compounds showed good quorum sensing inhibitors properties with an IC50 ranging from 7.12 ± 2.11 μM-92.34 ± 2.09 μM (4NPO, a reference compound, IC50 = 29.13 ± 0.88 μM). In addition, three out of the six compounds (4a, 4c, 4h) showed strong anti-biofilm formation and CviR inhibitory activity when compared to that of 4NPO. These biological data were also confirmed by computational studies. In this series of compounds, 4h is the most promising compound for future drug development targeting quorum sensing. Our results concluded that the fragment-based drug design is a good approach for the discovery of novel quorum-sensing inhibitors in the future.

Synthesis of Zinc Oxide Nanoparticles using Extract of Cynodon dactylon and Assessment of their Biological Activity against Staphylococcus aureus and Escherichia coli

Nanotechnology is a groundbreaking technology that that has been widely applied in creating materials which are useful in various fields. It's important to maintain eco-friendly approaches for synthesis of nanoparticles by diversifying the substrate sources. In this study, the researchers used aqueous extract of Cynodon dactylon to synthesize zinc oxide nanoparticles (ZnONPs). Quantitative phytochemical analysis of the extract showed high concentrations of alkaloids, flavonoids, carbohydrates, proteins, amino acids, and phenolic compounds. In contrast, moderate concentrations of tannins, oils, and fats, and low concentrations of phlorotannins, saponin, triterpenoids, and cardiac glycosides were found. Sterols, anthraquinone glycosides, gums, and mucilages were not detected in the extract. The synthesized ZnONPs showed absorbance ranging from 293 nm to 336 nm, with a peak at 307 nm. Fourier transform infrared (FTIR) spectroscopy revealed that the surface of the ZnONPs contained alcohol (intermolecular bonded), alkyne, amine salt, alkane, alkyne, aromatic compounds, conjugated alkene, amine, nitro compound, sulfonyl chloride, alkylaryl ether, and sulfoxide. Dynamic light scatering (DLS) analysis of the ZnONPs showed that its average size was 35.34±1.64 nm, and the polydispersity index was 0.6335. Spectrum of X ray diffraction indicated that peaks formed at 2θ and their corresponding orientation planes are 31.92o (100), 34.62o (002), 36.44o (101), 47.64o (102), 56.84o (110), 63.3o (200), and 68.16o (112). Transmission electron micrograph revealed the spherical shape, and nonuniform sizes of ZnONPs, which ranged from 0.52 nm to 8.32 nm. Antibacterial analysis of biosynthesized ZnONPs recorded 16±3.2 mm and 6.0±2.2 mm; 6.7±2.1 mm and 4.33±1.3 mm, 0.0±0.0 mm and 1.0±1.41 mm, against Staphylococcus aureus and Escherichia coli, at 53.3 mg/mL, 26.7 mg/mL and 13.3 mg/ml concentrations, respectively. At sub-inhibitory concentrations, biosynthesized ZnONPs demonstrated effective dose-dependent antibiofilm formation activity against E. coli and S. aureus. Consequently, extract of Cynodon dactylon is suitable for biosynthesis of ZnONPs with effective antibacterial and antibiofilm formation activities.

Anti-microbial efficacy of L-glutaminase (EC 3.5.1.2) against multidrug-resistant Pseudomonas aeruginosa infection.

The aims of this study were isolation-purification and characterization of L-glutaminase from L. gasseri BRLHM clinical isolates and investigation of its efficiency as an antimicrobial agent against multidrug-resistant P. aeruginosa. The MICs of L-glutaminase and gentamicin reference were evaluated by the well-diffusion method. The biofilm on the IUD contraceptive was visualized using atomic force microscopy (AFM) image analyses. The purified L-glutaminase possessed significant antimicrobial activity against P. aeruginosa isolates (p < 0.05), and the antibiofilm formation activity of the purified L-glutaminase was stronger than the antibiofilm activity of the referral standard drug, gentamicin (P < 0.05), which were checked by the inhibition of the biofilm formation on the IUD contraceptive device. Investigations indicated that L-glutaminase may have a crucial role in future clinical applications.

Wild Mushrooms: A Hidden Treasure of Novel Bioactive Compounds.

Secondary metabolites are hidden gems in mushrooms. Understanding these secondary metabolites' biological and pharmacological effects can be aided by identifying them. The purpose of this work was to profile the mycochemical components of the extracts of Auricularia auricula judae, Microporus xanthopus, Termitomyces umkowaani, Trametes elegans, and Trametes versicolor to comprehend their biological and pharmacological capabilities. Mushroom samples were collected from Kenya's Arabuko-Sokoke and Kakamega National Reserved Forests and identified using morphological and molecular techniques. Chloroform, 70% ethanol, and hot water solvents were used to extract the mycochemical components. Gas chromatography mass spectrometry (GC-MS) was used to analyze the chloroform, 70% ethanol, and hot water extracts of all the species examined. A total of 51 compounds were isolated from all extracts and classified as carboxylic acids, esters, phenols, fatty acids, alcohol, epoxides, aldehydes, fatty aldehydes, isoprenoid lipids, and steroids. Tetracosamethyl-cyclododecasiloxane (18.90%), oleic acid (72.90%), phenol, 2, 6-bis (1, 1-dimethylethyl)-4-methyl-, and methylcarbamate (26.56%) were all found in high concentrations in A. auricular judae, M. xanthopus, T. umkowaani, T. elegans, and T. versicolor, respectively. Fatty acids make up the majority of the compounds isolated from the T. elegans chloroform extract and the T. umkowaani 70% ethanol extract, respectively. Particularly, these fatty acids play crucial roles in the anti-inflammatory, hypocholesterolemic, anticancer, and antibiofilm formation activities. These bioactive elements indicate that the extracts of five wild mushrooms may be reliable sources of secondary metabolites for therapeutic development. Therefore, additional research is required to comprehend the usefulness of these chemicals in many functional areas and to improve the present understanding of macrofungi.

Antibiofilm Formation Activities of Ethanol Extract of Curcuma domestica Val. Rhizome Against Multidrug-resistant Acinetobacter baumannii

Abstract.&#x0D; &#x0D; Multidrug resistance is still a major health problem worldwide. Biofilm formation was related to the resistance of bacteria mechanism. Acinetobacter baumannii, one of the bacteria that cause nosocomial infections, is given particular attention due to its high prevalence of resistance. The current study address observing the antibacterial activity and antibiofilm formation activity of Curcuma domestica rhizome extract against multidrug-resistant Acinetobacter baumannii (MDR A.baumannii). Curcuma domestica rhizome was macerated by ethanol 96%. Determination of Minimum Inhibitory Concentration (MIC) was carried out by the microdilution method. Antibiofilm formation analysis was determined by standard quantitative using crystal violet-stained assay. Ethanol extract of C. domestica possesses antibacterial activity against MDR A. baumannii with MIC value 250 µg/mL. Additionally, the ethanol extract of C. domestica could inhibit the biofilm formation of MDR A.baumannii, thus percentage of biofilm formed only 23.7% and significance different with control after analyzed using ANOVA post hoc test Tukey. According to these results, ethanol extract of C. domestica revealed antibacterial activity and had the potency in suppressing the biofilm formation of MDR A.baumannii, thus could be utilized in clinical application, especially in MDR A.baumannii infection.&#x0D; &#x0D; Keywords: Antibiofilm, antibacterial, Curcuma domestica, multidrug-resistant, Acinetobacter baumannii&#x0D; &#x0D; &#x0D;

Thymol-Functionalized Hyaluronic Acid as Promising Preservative Biomaterial for the Inhibition of Candida albicans Biofilm Formation.

Hyaluronic acid (HA) is a naturally occurring biopolymer that has been employed for a plethora of medicinal applications. Nevertheless, as HA is a natural polysaccharide, it can be a substrate able to promote microbial growth and proliferation. Biopolymer-drug conjugates have gained attention over the years to overcome drawbacks of each single component. Within this context, thymol (Thy), a phenolic compound occurring in essential oils (EOs) extracted from Thymus and Origanum, has been largely studied for its antimycotic applications. However, it is characterized by a low water solubility and moderate cytotoxicity. Herein, we report an innovative HA-thymol conjugate (HA-Thy) biomaterial to circumvent the drawbacks of free thymol use by providing the polymer conjugate with the beneficial properties of both components. Preliminary biological tests evidenced the decrease of thymol cytotoxicity for the HA-Thy conjugate, paired with a promising antibiofilm formation activity against Candida albicans, similar to pure thymol, highlighting its potential application as a preservative biomaterial in formulations.

Time Kill Kinetic, Antibiofilm Activity and Effect on Biomolecules Release of Drypetes Gosswelleri and Echinops Giganteus Essential Oils on Bacteria

Finding alternative strategies to confront bacterial resistance is an urgent need. Biofilm-forming bacteria have become a serious problem in medicine. Bacteria can use biofilm as a mechanism of resistance against antibacterial drugs. The aim of this study was to study times kill kinetic of Drypetes gosswelleri and Echinops giganteus essential oils, the antibiofilm formation activity and their effect on cell release compounds. Times kill kinetic was study by quantification of cellular growth over time in Petri dish after her inoculation by the cells treated with antibacteria at MBC and incubation at different times during 24h. The antibiofilm activity carried out by microdilution using 96 wells microplate. The production of biofilms by cells treated was observed and quantified after coloration by Crystal Violet dye and spectrophotometric dosage at 630nm. The effect on cell release compounds are study by determination of absorbent material in extracellular medium at 260nm after exposure at the antibacterial during 24h. The results obtained showed that, these EOs have an ability to kill bacterial cells over time, Drypetes gossweileri EOs like Ciprofloxacin, caused the death of all the cells in the inoculum treated before 14h of exposure of Staphylococcus aureus strain. Against Salmonella enteritidis strain, Drypetes gossweileri and Echnops giganteus EOs kill all the cells after 24h like the two antibiotics. One effect of the action these EOs on the strains elucidated in this study was the leakage of intracellular absorbent materials (DNA and RNA) this materialized a diminution of membrane permeability and cell wall integrity.

Antibacterial and Antibiofilm Activity of Chemically and Biologically Synthesized Silver Nanoparticles.

Bacterial biofilms are a significant problem in the food industry, as they are difficult to eradicate and represent a threat to consumer health. Currently, nanoparticles as an alternative to traditional chemical disinfectants have garnered much attention due to their broad-spectrum antibacterial activity and low toxicity. In this study, silver nanoparticles (AgNPs) were synthesized by a biological method using a Jacaranda mimosifolia flower aqueous extract and by a chemical method, and the factors affecting both syntheses were optimized. The nanoparticles were characterized by Ultraviolet-visible (UV-Vis) spectrophotometry, Fourier-transform infrared spectroscopy (FTIR), Dynamic light scattering (DLS), X-ray diffraction (XRD), and Transmission electron microscopy (TEM) with a spherical and uniform shape. The antibacterial and antibiofilm formation activity was carried out on bacterial species of Pseudomonas aeruginosa and Staphylococcus aureus with the capacity to form biofilm. The minimum inhibitory concentration was 117.5 μg/mL for the chemical and 5.3 μg/mL for the biological nanoparticles. Both types of nanoparticles showed antibiofilm activity in the qualitative Congo red test and in the quantitative microplate test. Antibiofilm activity tests on fresh lettuce showed that biological nanoparticles decreased the population of S. aureus and P. aeruginosa by 0.63 and 2.38 logarithms, respectively, while chemical nanoparticles had little microbial reduction. In conclusion, the biologically synthesized nanoparticles showed greater antibiofilm activity. Therefore, these results suggest their potential application in the formulation of sanitizing products for the food and healthcare industries.

Elaboration and general evaluation of chitosan-based films containing terpene alcohols-rich essential oils

Recently, the scientific community is interested in the synthesis of biodegradable and bioactive packaging to replace oil-based ones. Therefore, the present study aims to elaborate an active and biodegradable material using chitosan (CS-film) combined with pelargonium, tea tree, marjoram, and thyme essential oils (EOs), and then evaluate their different properties and biological activities. The obtained data showed an augmentation in CS-film thickness and opacity following the addition of EOs ranging from 17 ± 3 to 42 ± 2μm and from 1.53 ± 0.04 to 2.67 ± 0.09, respectively. Furthermore, a significant decrease in the water vapor transmission rate and moisture content parameters was recorded as regards the treated CS-films. On the other hand, the treatment with EOs engenders random modifications in the physicochemical and mechanical characteristics of the material. Concerning the biological activities, the treated CS-films scavenged around 60% of DPPH radical while the control CS-film exhibited a negligible antioxidant activity. Finally, the CS-films containing pelargonium and thyme EOs exhibited the strongest antibiofilm-forming activity against Escherichia coli, Enterococcus hirae, Staphylococcus aureus, and Pseudomonas aeruginosa with values of inhibition greater than 70%. These encouraging results verify the effectiveness of CS-films containing EOs such as pelargonium and thyme EOs as biodegradable and bioactive packaging.

Unveiling Chemical, Antioxidant and Antibacterial Properties of Fagonia indica Grown in the Hail Mountains, Saudi Arabia.

The Aja and Salma mountains in the Hail region are home to a variety of indigenous wild plants, some of which are used in Bedouin folk medicine to treat various ailments. The purpose of the current study was to unveil the chemical, antioxidant and antibacterial properties of Fagonia indica (Showeka) grown widely in these mountains, as data on the biological activities of this plant in this remote area are scarce. XRF spectrometry indicated the presence of some essential elements, which were in the order of Ca > S > K > AL > CL > Si > P > Fe > Mg > Na > Ti > Sr > Zn > Mn. Qualitative chemical screening revealed the presence of saponins, terpenes, flavonoids, tannins, phenols and cardiac glycosides in the methanolic extract (80% v/v). GC-MS showed the presence of 2-chloropropanoic acid 18.5%, tetrahydro-2-methylfuran 20.1%, tridecanoic acid 12-methyl-, methyl ester 2.2%, hexadecanoic acid, methyl ester 8.6%, methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate 13.4%, methyl linoleate 7.0%, petroselinic acid methyl ester 15%, erucylamide 6.7% and diosgenin 8.5%. Total phenols, total tannins, flavonoids, DPPH, reducing power, -carotene and ABTS IC50 (mg/mL) scavenging activity were used to measure the antioxidant capabilities of Fagonia indica, which exhibited prominent antioxidant properties at low concentrations when compared to ascorbic acid, butylate hydroxytoluene and beta-carotene. The antibacterial investigation revealed significant inhibitory effects against Bacillus subtilis MTCC121 and Pseudomona aeruginosa MTCC 741 with inhibition zones of 15.00 ± 1.5 and 12.0 ± 1.0 mm, respectively. The MIC (minimum inhibitory concentration) and MBC (minimum bactericidal concentration) ranged between 125 to 500 μg/mL. The MBC/MIC ratio indicated possible bactericidal efficacy against Bacillus subtilis and bacteriostatic activity against Pseudomona aeruginosa. The study also showed that this plant has anti-biofilm formation activity.

Biogenic nanosilver bearing antimicrobial and antibiofilm activities and its potential for application in agriculture and industry.

Due to the increasing resistance of bacteria and fungi to antimicrobials, it is necessary to search for effective alternatives to prevent and treat pathogens causing diseases in humans, animals, and plants. In this context, the mycosynthesized silver nanoparticles (AgNPs) are considered as a potential tool to combat such pathogenic microorganisms. AgNPs were synthesized from Fusarium culmorum strain JTW1 and characterized by Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, Nanoparticle Tracking Analysis (NTA), Dynamic Light Scattering (DLS) and Zeta potential measurement. The minimum inhibitory (MIC) and biocidal concentrations (MBC) were determined against 13 bacterial strains. Moreover, the combined effect of AgNPs with antibiotics (streptomycin, kanamycin, ampicillin, tetracycline) was also studied by determining the Fractional Inhibitory Concentration (FIC) index. The anti-biofilm activity was examined by crystal violet and fluorescein diacetate (FDA) assays. Furthermore, antifungal activity of AgNPs was evaluated against a panel of phytopathogenic fungi viz., Botrytis, Colletotrichum, Fusarium, Phoma, Sclerotinia, and an oomycete pathogen Phytophthora by agar well-diffusion and micro-broth dilution method to evaluate the minimal AgNPs concentrations that inhibit fungal spore germination. Fungi-mediated synthesis resulted in the formation of small (15.56 ± 9.22 nm), spherical and stable (zeta potential of - 38.43 mV) AgNPs with good crystallinity. The results of FTIR spectroscopy indicated the presence of various functional groups, namely hydroxyl, amino, and carboxyl ones, from the biomolecules on the surface of AgNPs. The AgNPs showed antimicrobial and antibiofilm formation activities against Gram-positive and Gram-negative bacteria. The values of MIC and MBC ranged between 16-64 and 32-512 μg mL-1, respectively. The enhanced effect of AgNPs in combination with antibiotics was confirmed against human pathogens. The highest synergistic effect (FIC = 0.0625) was demonstrated by the combination of AgNPs with streptomycin against two strains of Escherichia coli (ATCC 25922 and ATCC 8739), followed by Klebsiella pneumoniae and Pseudomonas aeruginosa (FIC = 0.125). Enhanced effects of AgNPs with ampicillin were also shown against Staphylococcus aureus ATCC 25923 (FIC = 0.125) and P. aeruginosa (FIC = 0.25), as well as kanamycin against S. aureus ATCC 6538 (FIC = 0.25). The crystal violet assay revealed that the lowest concentration of AgNPs (0.125 μg mL-1) reduced the development of biofilms of Listeria monocytogenes and Salmonella enterica, while the maximum resistance was shown by Salmonella infantis, its biofilm was reduced after exposure to a concentration of 512 μg mL-1. A high inhibitory effect on the activity of bacterial hydrolases was observed by the FDA assay. AgNPs at a concentration of 0.125 μg mL-1 reduced the hydrolytic activity of all biofilms formed by the tested pathogens, except E. coli ATCC 25922, P. aeruginosa, and Pectobacterium carotovorum (efficient concentration was 2-fold higher, at 0.25 μg mL-1), while the hydrolytic activity of E. coli ATCC 8739, Salmonella infantis and S. aureus ATCC 6538 was suppressed after treatment with AgNPs at concentrations of 0.5, 2 and 8 μg mL-1, respectively. Moreover, AgNPs inhibited fungal growth and spore germination of Botrytis cinerea, Phoma lingam, and Sclerotinia sclerotiorum. MIC and MFC values of AgNPs against spores of these fungal strains were determined at 64, 256, and 32 μg mL-1, and zones of growth inhibition were 4.93, 9.54, and 3.41 mm, respectively. Fusarium culmorum strain JTW1 was found to be an eco-friendly biological system for an easy, efficient and inexpensive synthesis of AgNPs. In our study, the mycosynthesised AgNPs demonstrated remarkable antimicrobial (antibacterial and antifungal) and antibiofilm activities against a wide range of human and plant pathogenic bacteria and fungi singly and in combination with antibiotics. These AgNPs could be applied in medicine, agriculture, and food industry to control such pathogens that cause numerous human diseases and crop losses. However, before using them extensive animal studies are required to evaluate the toxicity, if any.

Antibiofilm formation activities of ethanol extracts from Curcuma domestica rhizome against bacteria resistant Pseudomonas aeruginosa

The Biofilm P.aeruginosa communities are characterized by close juxtaposition of bacterial cells and the presence of an exopolysaccharide matrix that surrounds the bacterial population. Many reports have postulated that the exopolysaccharide matrix provides an effective barrier that restricts penetration of chemically reactive biocides, cationic antibiotics and antimicrobial peptides. This study aims to antibiofilm formation activities of ethanol extract from Curcuma domestica against Pseudomonas aeruginosa resistant bacteria. These antibiofilm formation was determined using a modified-method of microdilution assay. Ethanol extract of C. domestica strong activity against P.aeruginosa with Anti-biofilm activity was observed through biofilm inhibition and degradation activities, determined by Cristal Violet assay. Data were analyzed using ANOVA test and Tukey HSD post hoc test. The significant inhibition of P.aeruginosa the biofilm degradation was obtained at a concentration of 31.2 µg/ml until 250 µg/ml. The ethanol extract of C. domestica have potency as alternative antibiofilm formation against selected bacteria resistant.

Antimicrobial and antibiofilm forming activity of Origanum munzurense against some Gram-Positive bacteria and yeast

In vitro antimicrobial and antibiofilm forming activities of Origanum munzurense extract were investigated against some gram-positive bacteria and yeast strains. Liquid microdilution method and microplate method were used for antimicrobial and antibiofilm forming activities, respectively. Minimal inhibitory concentration values were found to be 2 mg/ml for Enterococcus faecalis ATCC 29212, 64 mg/ml for Listeria monocytogenes RSKK 02028, 2 mg/ml for L. monocytogenes RSKK 472, 2 mg/ml for Bacillus cereus NRRL 569 , 128 mg/ml for S. aureus ATCC 25923, 32 mg/ml for S. aureus (MRSA) ATCC 43300 strain, 64 mg/ml for Candida tropicalis ATCC 13803, 2 mg/ml for C. albicans ATCC 90028, 1 mg/ml for S. aureus FRI 918 and 1 mg/ml for Staphylococcus epidermidis ATCC 12228 strain. The extract prevented the biofilm formations of E. faecalis ATCC 29212, S. aureus FRI 918 and S.epidermidis ATCC 12228 at concentrations of 2 mg/ml, 500 µg/ml and 250 µg/ml, respectively. No biofilm formation was observed for the other bacteria tested.As a result, Origanum munzurense extract has antibacterial and antibiofilm activity on the selected pathogenic microorganisms tested. Due to these properties of O. munzurense, it could be considered as a plant-based antimicrobial agent to be used especially in the food industry.

The morphology and structural features of self-aggregating hexapeptides with antibiofilm formation activity

Though self-aggregating peptides all aggregate into fibrils, they have been found to exert different roles against microbes, and the reasons remain unknown.

Antimicrobial Activity of Ardisia serrata (Cavs.) Pers. Ethanolic and Aqueous Leaf Extract on the Growth and Biofilm Formation of Selected Bacterial Isolates.

Ardisia serrata (Aunasin) is an endemic Philippine plant of the family Primulaceae, with several studies showing the genus Ardisia as having potential antibacterial, antiangiogenic, cytotoxic, and antipyretic properties. This study aims to determine the antibacterial and antibiofilm-forming activity of Ardisia serrata ethanolic and aqueous extracts on Escherichia coli, Methicillin-Sensitive Staphylococcus aureus (MSSA), and Methicillin-Resistant Staphylococcus aureus (MRSA). This is an experimental study testing the activity against bacterial strains of E. coli, MSSA, and MRSA using ethanolic and aqueous extracts of A. serrata leaves. Microtiter susceptibility and biofilm inhibition assays were done with two-fold dilutions of the extract against the selected strains using spectrophotometry with optical density (OD) at 600 nm and 595 nm, respectively, to quantify bacterial growth and biofilm inhibition. The bacterial susceptibility and biofilm inhibition activity was reported as percent inhibition (PI). Minimum inhibitory concentration (MIC), and minimum biofilm inhibition concentration (MBIC) values were obtained using logarithmic regression of the PI values. A. serrata ethanolic extracts showed weak growth inhibitory activity against MSSA and MRSA with minimum inhibitory concentration (MIC) values of 2.6192 and 3.2988 mg/mL, respectively, but no biofilm inhibition activity was noted, while the aqueous extracts exhibited negligible biofilm inhibition activity against MSSA and MRSA with minimum biofilm inhibition concentration (MBIC) values of 13.5972 and 8964.82 mg/mL, respectively, and with no growth inhibition activity. Both ethanolic and aqueous extracts showed no growth inhibition and biofilm inhibition activities against E. coli. Staphylococcus aureus is susceptible to the bioactivity of the leaf extracts of A. serrata and has potential to be used as an antibacterial in the treatment of infectious diseases.