Antimicrobial Effects Research Articles

A Safer Method for Disinfection of Bacillus Calmette-Guerin-Containing Urine: A Prospective, Randomized Study.

The aim of the study was to examine whether disinfection of bacillus Calmette-Guerin-containing urine with etaprocohol® (ethanol 76.9-81.4 vol % and isopropanol as an additive) is safer than disinfection with sodium hypochlorite. In prospective research, safety and efficacy was analyzed in 5 patients in the etaprocohol® disinfection group and 5 patients in the sodium hypochlorite disinfection group. The primary endpoint was the temperature change after disinfection and the secondary endpoint was the unpleasantness of the odor caused by disinfection. Additionally, concentration of gas produced was also examined. Sensory tests were taken from staff who performed urine disinfection and the odor generated by disinfection was evaluated. As a safety protocol, post-BCG-treated urine is cultured to verify the negativity for mycobacteria. Mycobacteria were disinfected in all cases. The temperature rise following disinfection was significantly higher in the sodium hypochlorite group. The sensory test outcomes were significantly worse in the group disinfected with sodium hypochlorite. The concentration of gas generated immediately after disinfection in both groups reached the maximum value and declined quickly. Disinfection of bacillus Calmette-Guerin-containing urine with etaprocohol® was safer than disinfection with sodium hypochlorite, and an equivalent disinfection effect was achieved.

Kombucha as a Health-Beneficial Drink for Human Health.

Kombucha is a unique fermented beverage made from a symbiotic culture of yeast and bacteria. Kombucha is normally based on black tea added to water, then sugar is added as a substrate for fermentation in this beverage. This unique beverage is composed of amino acids, flavonoids, vitamins, and some active enzymes. Several beneficial health effects such as antioxidant, antimicrobial effects have been reported as a result of probiotics and prebiotics presence. These health effects of kombucha are attributed to its bioactive chemical and biological agents of probiotics bacteria e.g., Gluconobacter, Acetobacter and yeasts like Saccharomyces sps., along with glucuronic acid as the main sources of the health protection. This review focuses on the beneficial effects of Kombucha including antimicrobial, antioxidant, anti-cancer antidiabetic properties, as well as liver protection, treat of gastrointestinal problems, AIDS, gastric ulcers, obesity (and energy production), detoxification, and skin health.

Comparative Study of Toxic Terpenoidal Aldehydes and Lactone Derivatives from the European Polypore Bondarzewia mesenterica.

Two unprecedented isomeric secondary metabolites named vibralactones Z5 (1a) and Z6 (1b), in addition to eleven known compounds (2-12), were isolated from solid-state rice culture medium of Bondarzewia mesenterica (Bondarzewiaceae). Chemical structures of the isolated compounds were established via spectral analyses. The new lactone derivatives were weakly active against Staphylococcus aureus without any significant cytotoxicity, while the molecules containing an aldehyde functionality showed significant antimicrobial and cytotoxic effects. For instance, erinacine P (7) and (+)-isovelleral (8) and erinacine P (7) were cytotoxic against all tested cell lines at IC50 values in the ranges of 3.5-14.2 and 2.8-30.2 μM, respectively. In addition, they revealed moderate antimicrobial activity with the lowest minimum inhibitory concentration (MIC) values recorded against Mucor hiemalis (8.3 μg/mL), Pichia anomala, and Rhodotorula glutinis at 16.6 μg/mL.

Low-temperature plasma jet suppresses bacterial colonisation and affects wound healing through reactive species.

An argon-based low-temperature plasma jet (LTPJ) was used to treat chronically infected wounds in Staphylococcus aureus-laden mice. Based on physicochemical property analysis and in vitro antibacterial experiments, the effects of plasma parameters on the reactive nitrogen and oxygen species (RNOS) content and antibacterial capacity were determined, and the optimal treatment parameters were determined to be 4 standard litre per minute and 35 W. Additionally, the plasma-treated activation solution had a bactericidal effect. Although RNOS are related to the antimicrobial effect of plasma, excess RNOS may be detrimental to wound remodelling. In vivo studies demonstrated that medium-dose LTPJ promoted MMP-9 expression and inhibited bacterial growth during the early stages of healing. Moreover, LTPJ increased collagen deposition, reduced inflammation, and restored blood vessel density and TGF-β levels to normal in the later stages of wound healing. Therefore, when treating chronically infected wounds with LTPJ, selecting the medium dose of plasma is more advantageous for wound recovery. Overall, our study demonstrated that low-temperature plasma jets may be a potential tool for the treatment of chronically infected wounds.

An eco-friendly spectrophotometric analysis tool with whiteness assessment to assay erythromycin in pharmaceutical formulation through metal complexation with Ni2+: application to the microbiological activity using agar diffusion method

A new, facile and eco-friendly spectrophotometric method for estimating erythromycin (ERY) in its dosage form has been proposed and validated. It depends on the formation of a complex between the drug and nickel at pH 7, using distilled water as a diluent, where the absorbance of the generated complex was measured at 228.5 nm. The formed complex followed a linear response over the concentration range of 80.0 to 300.0 µg/mL of ERY. The proposed method was fully validated according to international conference of harmonization (ICH) and was used to estimate the relevant concentration of the drug in its oral suspension formulation providing mean percentage recovery of 100.0±1.08 with a limit of detection and limit of quantification of 60 µg/mL and 80 µg/mL, respectively. the reaction stoichiometry was investigated and a reaction mechanism proposal was offered. Eventually, the antimicrobial effect of ERY and its metal complex with Ni2+ were compared using agar diffusion method, where no significant difference in their activities was observed.

Illuminating microflora: shedding light on the potential of blue light to modulate the cutaneous microbiome.

Cutaneous diseases (such as atopic dermatitis, acne, psoriasis, alopecia and chronic wounds) rank as the fourth most prevalent human disease, affecting nearly one-third of the world's population. Skin diseases contribute to significant non-fatal disability globally, impacting individuals, partners, and society at large. Recent evidence suggests that specific microbes colonising our skin and its appendages are often overrepresented in disease. Therefore, manipulating interactions of the microbiome in a non-invasive and safe way presents an attractive approach for management of skin and hair follicle conditions. Due to its proven anti-microbial and anti-inflammatory effects, blue light (380 - 495nm) has received considerable attention as a possible 'magic bullet' for management of skin dysbiosis. As humans, we have evolved under the influence of sun exposure, which comprise a significant portion of blue light. A growing body of evidence indicates that our resident skin microbiome possesses the ability to detect and respond to blue light through expression of chromophores. This can modulate physiological responses, ranging from cytotoxicity to proliferation. In this review we first present evidence of the diverse blue light-sensitive chromophores expressed by members of the skin microbiome. Subsequently, we discuss how blue light may impact the dialog between the host and its skin microbiome in prevalent skin and hair follicle conditions. Finally, we examine the constraints of this non-invasive treatment strategy and outline prospective avenues for further research. Collectively, these findings present a comprehensive body of evidence regarding the potential utility of blue light as a restorative tool for managing prevalent skin conditions. Furthermore, they underscore the critical unmet need for a whole systems approach to comprehend the ramifications of blue light on both host and microbial behaviour.

Synthesis, evaluation, and in silico studies of imidazolium and pyridinium-based ionic liquids with Dioctyl succinamic acid anion for enhanced antibacterial applications

A substantial public health risk is bacterial infections, but the effectiveness of antibiotics has declined due to their overuse. In the quest for effective antimicrobial agents, Ionic liquids (ILs) have emerged as promising candidates. We have described the synthesis and comparison of pyridinium- and imidazolium-based ILs using bromide and dioctyl succinamate (DOSA) anions. These synthesized ILs were tested for their antibacterial efficacy against gram-positive Staphylococcus aureus, gram-negative Escherichia coli, and Pseudomonas aeruginosa using the agar disc diffusion method. The ILs based on Imidazolium cation showed better antibacterial activities against Staphylococcus aureus. The least MIC values of 0.244 mM and 0.488 mM are shown by [C88im] [Br] and [C88im] [DOSA] respectively, showing the key effect of a counter ion with Imidazolium ILs.

Orally Administered Lactobacillus rhamnosus CY12 Alleviates DSS-Induced Colitis in Mice by Restoring the Intestinal Barrier and Inhibiting the TLR4-MyD88-NF-κB Pathway via Intestinal Microbiota Modulation.

Oral ingestion of probiotics is a promising approach to relieving inflammatory disease through regulating the gut microbiota. A newly discovered strain, Lactobacillus rhamnosus CY12 (LCY12), obtained from cattle-yak milk, displayed numerous probiotic properties. These included enhanced viability in low pH and bile environments, adhesion capabilities, and potent antimicrobial effects. The research aimed to explore the beneficial impacts of the novel LCY12 strain on colitis in mice induced by dextran sulfate sodium (DSS) and to elucidate the underlying molecular mechanisms. The results of the study showed that administration of LCY12 effectively helped to reduce the negative effects of DSS-induced body weight loss, disease activity index score, colon length shortening, loss of goblet cells, and overall histopathological scores in the intestines. Simultaneously, LCY12 administration significantly alleviated intestinal inflammation and safeguarded intestinal barrier integrity by enhancing IL-10 levels, while dampening IL-6, IL-1β, and TNF-α production. Additionally, LCY12 boosted the presence of tight junction proteins. Furthermore, LCY12 hindered the TLR4/MyD88/NF-κB signaling pathway by downregulating TLR4 and MyD88 expression, inactivating phosphorylated IκBα, and preventing translocation of NF-κB p65 from the cytoplasm to the nucleus. The LCY12 also increased specific intestinal microbial communities and short-chain fatty acid (SCFA) production. Altogether, LCY12 oral administration alleviated colitis induced with DSS in mice by improving intestinal barrier function and regulating inflammatory cytokines, SCFA production, and intestinal microbiota.

A Comprehensive Review of Recent Research into the Effects of Antimicrobial Peptides on Biofilms-January 2020 to September 2023.

Microbial biofilm formation creates a persistent and resistant environment in which microorganisms can survive, contributing to antibiotic resistance and chronic inflammatory diseases. Increasingly, biofilms are caused by multi-drug resistant microorganisms, which, coupled with a diminishing supply of effective antibiotics, is driving the search for new antibiotic therapies. In this respect, antimicrobial peptides (AMPs) are short, hydrophobic, and amphipathic peptides that show activity against multidrug-resistant bacteria and biofilm formation. They also possess broad-spectrum activity and diverse mechanisms of action. In this comprehensive review, 150 publications (from January 2020 to September 2023) were collected and categorized using the search terms 'polypeptide antibiotic agent', 'antimicrobial peptide', and 'biofilm'. During this period, a wide range of natural and synthetic AMPs were studied, of which LL-37, polymyxin B, GH12, and Nisin were the most frequently cited. Furthermore, although many microbes were studied, Staphylococcus aureus and Pseudomonas aeruginosa were the most popular. Publications also considered AMP combinations and the potential role of AMP delivery systems in increasing the efficacy of AMPs, including nanoparticle delivery. Relatively few publications focused on AMP resistance. This comprehensive review informs and guides researchers about the latest developments in AMP research, presenting promising evidence of the role of AMPs as effective antimicrobial agents.

Evaluating the Performance of UV Disinfection across the 222-365 nm Spectrum against Aerosolized Bacteria and Viruses.

Bioaerosols play a significant role in the transmission of many infectious diseases, especially in enclosed indoor environments. Ultraviolet (UV) disinfection has demonstrated a high efficacy in inactivating microorganisms suspended in the air. To develop more effective and efficient UV disinfection protocols, it is necessary to evaluate and optimize the effectiveness of UV disinfection against aerosolized bacteria and viruses across the entire UV spectrum. In this study, we evaluated the performance of UV disinfection across the UV spectrum, ranging from 222 to 365 nm, against aerosolized bacteria and viruses, including Escherichia coli, Staphylococcus epidermidis, Salmonella enterica, MS2, P22, and Phi6. Six commonly available UV sources, including gas discharge tubes and light-emitting diodes with different emission spectra, were utilized, and their performance in terms of inactivation efficacy, action spectrum, and energy efficiency was determined. Among these UV sources, the krypton chloride excilamp emitting at a peak wavelength of 222 nm was the most efficient in inactivating viral bioaerosols. A low-pressure mercury lamp emitting at 254 nm performed well on both inactivation efficacy and energy efficiency. A UV light-emitting diode emitting at 268 nm demonstrated the highest bacterial inactivation efficacy, but required approximately 10 times more energy to achieve an equivalent inactivation level compared with that of the krypton chloride excilamp and low-pressure mercury lamp. This study provides insights into UV inactivation on bioaerosols, which can guide the development of effective wavelength-targeted UV air disinfection technologies and may significantly help reduce bioaerosol transmission in public areas.

Peppermint oil‐infused polylactic acid films: A novel approach for antimicrobial and biodegradable food packaging

AbstractExtensive research is currently dedicated to creating biodegradable packaging materials that match the qualities of traditional synthetic packaging materials. Among these options, polylactic acid (PLA) is noteworthy. PLA is a renewable‐source‐derived thermoplastic polymer with excellent barrier properties, mechanical strength, and a strong safety profile. To enhance food product shelf life, active packaging materials, incorporating functional ingredients like antimicrobials, have gained prominence. Peppermint essential oil is one such active ingredient, offering potential improvements in preserving food freshness and safety. This study's objective is to craft antimicrobial, biodegradable food packaging materials by blending peppermint oil into PLA films. Various peppermint oil concentrations (1.25%, 1.875%, and 2.5% w/v) were blended with PLA to assess their impact on opacity, water vapor permeability (WVP), mechanical and thermal properties, and antimicrobial characteristics. Higher peppermint oil concentrations increased opacity, making them advantageous for light‐sensitive food items. These films reduced WVP without affecting PLA's thermal stability. Antimicrobial effectiveness was evaluated against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), showing inhibition with 1.875% and 2.5% w/v peppermint oil concentrations. Compared to control, PLA films with peppermint oil extended the shelf life of packaged chicken breast meats from 3 to 8 days. As a result, incorporating peppermint oil into PLA films presents a promising solution for advanced antimicrobial and biodegradable food packaging.Highlights The incorporation of peppermint oil resulted in higher opacity values. Peppermint incorporated PLA films showed antimicrobial activity. Peppermint oil addition decreased water vapor permeability of PLA films. Peppermint oil added PLA films increased the shelf life of chicken meat up to 8 days.

Antioxidant Properties of Brassica Rapa L. Seeds and Immunostimulant Effect on Immunity Broilers Cells (Gallus Gallus Domesticus)

Background: In the past few decades, researchers have focused on finding the benefits of natural substances derived from plants. Objective: This study aimed to evaluate the use of Brassica rapa seeds in poultry feed as an antioxidant and immunostimulant of host defenses. Methods: We prepared three extracts using ethanol, Ethyl Acetate, and water. Spectrophotometric methods determined the total phenolic and flavonoid content in the three extracts. Antioxidant activity was assessed using 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing/antioxidant power (FRAP), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radicals and β-Carotene bleaching methods. An assessment of their immunostimulant activities in vitro was performed on chicken immunity cell proliferation (splenocytes, thymocytes, and Bursa cells) and IgY production. method: We prepared three different extracts using ethanol, Ethyl Acetate, and water. The total phenolic and flavonoid content in the three extracts was determined by spectrophotometric methods.Antioxidant activity has been assessed using 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing/antioxidant power (FRAP), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radicals and β-Carotene bleaching methods. Assessment of their immunostimulant activities in vitro was tested on chicken immunity cell proliferation (splenocytes, thymocytes, and Bursa cells) and IgY production Results: The total phenolic contents ranged from 462.5 to 794.8 mg /g of extract, the order of TPC was as follows: EtOAc > EtOH >Water. Flavonoid contents were, 63.7 mg in EtOH extract, 81.2 mg in EtOAc extract, and 108.7 mg/g Extract in aqueous extract. By DPPH, the IC50s of EtOH, EtOAc, and water, were 1.8μg/ml, 2.4μg/ml, and 1.5μg/ml, respectively. Using the Ferric- Reducing Antioxidant Power (FRAP), we remarked that the EtOH and EtOAc extracts have important antioxidant powers. The ABTS assay indicated that EtOH and water had the highest activities with IC50s of 0.19 and 0.07, respectively. Finally, by the β-carotene bleaching test, we observed that the IC50 of the EtOH, EtOAc, and water were 62.1 μg/mL; 72.7 μg/mL, and 45.8 μg/mL, respectively. The results obtained indicate that Brassica aqueous extract stimulates humoral immunity by stimulating splenocyte (B and T-lymphocytes) and Bursa cell (B-lymphocyte) proliferation by more than 200% of response vs control. In addition, the aqueous extract highly stimulated the function of bursa cells by 208% of the reaction. In the same conditions, we recorded a stimulation of cellular immunity mediated by thymocytes by an increase in cell proliferation (352.7% of response) implicated in virus protection. These extracts also possessed an antimicrobial effect against diverse microorganisms such as coliforms and Staphylococcus. The FT-IR spectrum indicated that the hydroxyl group (phenol), hydroxybenzoic acid family, carbohydrate molecules such as glucopyranose, a carbonyl ester group, hydrocarbon chains (alkyls groups)) were present. result: The total phenolic contents ranged from 462.5 to 794.8 mg /g of Extract, the order of TPC was as follows: EtOAc > EtOH >Water. Flavonoid contents were, 63.7 mg in EtOH extract, 81.2 mg in EtOAc extract, and 108.7 mg/g Extract in aqueous extract.By DPPH, the IC50s of EtOH, EtOAc, and water, were respectively 1.8µg/ml, 2.4µg/ml, and 1.5µg/ml. Using the ferric-reducing antioxidant power (FRAP) we remarked that the EtOH and EtOAc extracts have important antioxidant powers. The ABTS assay indicated that EtOH and water had the highest activities with IC50s of 0.19 and 0.07 respectively. Finally, by the β-carotene bleaching test, we observed that the IC50 of the EtOH, EtOAc, and water were 62.1 µg/mL; 72.7 µg/mL, and 45.8 µg/mL respectively. The results obtained indicate that Brassica aqueous extract stimulates humoral immunity by stimulating splenocyte (B and T-lymphocytes) and Bursa cell (B-lymphocyte) proliferation by more than 200% of response vs control. In addition, the aqueous extract stimulated highly the function of bursa cells by 208% of the response. In the same conditions, we recorded a stimulation of cellular immunity mediated by thymocytes by an increase in cell proliferation (352.7% of response) implicated in virus protection. These extracts possessed also an antimicrobial effect against diverse microorganisms such as coliforms and Staphylococcus. The FT-IR spectrum indicated that the hydroxyl group (phenol), hydroxybenzoic acid family, carbohydrate molecules such as glucopyranose, a carbonyl ester group, hydrocarbon chains (alkyls groups)) were present. Conclusion: This result could have interesting applications in the poultry feed industry to enhance the performance of animal development.

Synthesis and evaluation of a novel vancomycin-infused, biomimetic bone graft using a rat model of spinal implant-associated infection

BackgroundPostoperative infection is a complication of spinal fusion surgery resulting in increased patient morbidity. Strategies including intraoperative application of powdered vancomycin have been proposed to reduce the incidence of infection; however, such antimicrobial effects are short-lived. MethodsInstrumentation of the L4–L5 vertebrae was performed mimicking pedicle screw and rod fixation in 30 rats. Titanium instrumentation inoculated with either PBS or 1×105 CFU bioluminescent MRSA, along with biomimetic bone grafts infused with varying concentrations of vancomycin and 125 µg of rhBMP-2 (BioMim-rhBMP-2-VCM) were implanted prior to closure. Infection was quantified during the six-week postoperative period using bioluminescent imaging. Arthrodesis was evaluated using micro-CT. ResultsInfected animals receiving a bone graft infused with low-dose (0.18 mg/g) or high-dose vancomycin (0.89 mg/g) both exhibited significantly lower bioluminescent signal over the six-week postoperative period than control animals inoculated with MRSA and implanted with bone grafts lacking vancomycin (p=.019 and p=.007, respectively). Both low and high-dose vancomycin-infused grafts also resulted in a statistically significant reduction in average bioluminescence when compared to control animals (p=.027 and p=.047, respectively), independent of time. MicroCT analysis of animals from each group revealed pseudoarthrosis only in the control group, suggesting a correlation between infection and pseudoarthrosis. MRSA-inoculated control animals also had significantly less bone volume formation on micro-CT than the PBS-inoculated control cohort (p<.001), the MRSA+low-dose vancomycin-infused bone graft cohort (p<.001), and the MRSA+high-dose vancomycin-infused bone graft cohort (p<.001). ConclusionBioMim-rhBMP-2-VCM presents a novel tissue engineering approach to simultaneously promoting arthrodesis and antimicrobial prophylaxis in spinal fusion. Despite mixed evidence of potential osteotoxicity of vancomycin reported in literature, BioMim-rhBMP-2-VCM preserved arthrodesis and osteogenesis with increasing vancomycin loading doses due to the graft's osteoinductive composition.

Evaluation of novel copper-based antimicrobial admixtures for biocorrosion mitigation of cement paste

Copper-based antimicrobial admixtures have been favoured for mitigating microbially induced concrete corrosion (MICC) owing to their practical bactericidal abilities. However, concerns regarding the leachability of hazardous components and the long-term efficacy of these admixtures have hindered their industrial application, with limited understanding of their comparative antimicrobial performance and mechanisms. In this work, three conventional copper compounds (copper sulphate, copper acetate, and copper oxide) and two newly synthesized copper-modified admixtures (copper-exchanged montmorillonite and copper-chelated chitosan) were evaluated and compared in terms of their impact on the properties, biocorrosion resistance, and environmental impact of cement paste. The findings revealed that the inclusion of copper-containing admixtures led to increased slump flow, extended setting time, improved compressive strength, lowered porosity, and reduced corrosion depth in the cement paste. Compared with copper sulphate and copper oxide, copper acetate exhibited superior engineering properties, antimicrobial performance, and reduced copper ion leaching. Cu-modified montmorillonite emerged as the most effective copper-based antimicrobial agent, considerably reducing the corrosion depth of cement paste by 32.8 % with the lowest copper leaching, suggesting its potential as a sustainable solution for antimicrobial concrete applications. In contrast, adding chitosan led to poor mechanical and adverse antimicrobial performance, indicating its limited potential as a carrier for synthesized antimicrobial agents.

Antimicrobial Photodynamic Therapy Using Encapsulated Protoporphyrin IX for the Treatment of Bacterial Pathogens.

Herein, we report on the antimicrobial photodynamic effect of polymeric nanoparticles containing the endogenous photosensitizer protoporphyrin IX. Compared to equivalent doses of the free photosensitizer, we demonstrated that the photodynamic antimicrobial efficacy of PLGA (polylactic-co-glycolic acid) nanoparticles containing protoporphyrin IX (PpIX) against pathogenic Staphylococcus aureus (S. aureus) is preserved after encapsulation, while photobleaching is reduced. In addition, compared to equivalent doses of the free porphyrin, we show that a reduction in the cytotoxicity in mammalian cell cultures is observed when encapsulated. Therefore, the encapsulation of protoporphyrin IX reduces its photodegradation, while the released photosensitizer maintains its ability to generate reactive oxygen species upon light irradiation. The polymeric nanoencapsulation promotes aqueous solubility for the hydrophobic PpIX, improves its photostability and reduces the cytotoxicity, while providing an extended release of this endogenous photosensitizer.

Metabolite profiling and bioactivity guided fractionation of Lactobacillaceae and rice bran postbiotics for antimicrobial-resistant Salmonella Typhimurium growth suppression.

Probiotic-fermented supplements (postbiotics) are becoming increasingly explored for their activity against antibiotic-resistant enteropathogens. Prebiotics are often incorporated into postbiotics to enhance their efficacy, but due to strain differences in probiotic activity, postbiotic antimicrobial effects are poorly understood. To improve postbiotic antimicrobial efficacy, we investigated and compared metabolite profiles of postbiotics prepared with three lactic acid bacteria strains (L. fermentum, L. paracasei, and L. rhamnosus) cultured with and without rice bran, a globally abundant, rich source of prebiotics. At their minimum inhibitory dose, L. fermentum and L. paracasei postbiotics + rice bran suppressed S. Typhimurium growth 42-55% more versus their respective probiotic-alone postbiotics. The global, non-targeted metabolome of these postbiotics identified 109 metabolites increased in L. fermentum and L. paracasei rice bran postbiotics, including 49 amino acids, 20 lipids, and 12 phytochemicals metabolites. To identify key metabolite contributors to postbiotic antimicrobial activity, bioactivity-guided fractionation was applied to L. fermentum and L. paracasei rice bran-fermented postbiotics. Fractionation resulted in four L. fermentum and seven L. paracasei fractions capable of suppressing S. Typhimurium growth more effectively versus the negative control. These fractions were enriched in 15 metabolites that were significantly increased in the global metabolome of postbiotics prepared with rice bran versus postbiotic alone. These metabolites included imidazole propionate (enriched in L. fermentum + rice bran, 1.61-fold increase; L. paracasei + rice bran 1.28-fold increase), dihydroferulate (L. fermentum + rice bran, 5.18-fold increase), and linoleate (L. fermentum + rice bran, 1.82-fold increase; L. paracasei + rice bran, 3.19-fold increase), suggesting that they may be key metabolite drivers of S. Typhimurium growth suppression. Here, we show distinct mechanisms by which postbiotics prepared with lactic acid bacteria and rice bran produce metabolites with antimicrobial activity capable of suppressing S. Typhimurium growth. Probiotic strain differences contributing to postbiotic antimicrobial activity attract attention as adjunctive treatments against pathogens.

Inhibition of Clinical MRSA Isolates by Coagulase Negative Staphylococci of Human Origin.

Staphylococcus aureus is frequently highlighted as a priority for novel drug research due to its pathogenicity and ability to develop antibiotic resistance. Coagulase-negative staphylococci (CoNS) are resident flora of the skin and nares. Previous studies have confirmed their ability to kill and prevent colonization by S. aureus through the production of bioactive substances. This study screened a bank of 37 CoNS for their ability to inhibit the growth of methicillin-resistant S. aureus (MRSA). Deferred antagonism assays, growth curves, and antibiofilm testing performed with the cell-free supernatant derived from overnight CoNS cultures indicated antimicrobial and antibiofilm effects against MRSA indicators. Whole genome sequencing and BAGEL4 analysis of 11 CoNS isolates shortlisted for the inhibitory effects they displayed against MRSA led to the identification of two strains possessing complete putative bacteriocin operons. The operons were predicted to encode a nukacin variant and a novel epilancin variant. From this point, strains Staphylococcus hominis C14 and Staphylococcus epidermidis C33 became the focus of the investigation. Through HPLC, a peptide identical to previously characterized nukacin KQU-131 and a novel epilancin variant were isolated from cultures of C14 and C33, respectively. Mass spectrometry confirmed the presence of each peptide in the active fractions. Spot-on-lawn assays demonstrated both bacteriocins could inhibit the growth of an MRSA indicator. The identification of natural products with clinically relevant activity is important in today's climate of escalating antimicrobial resistance and a depleting antibiotic pipeline. These findings also highlight the prospective role CoNS may play as a source of bioactive substances with activity against critical pathogens.

Formulation and Characterization of Curcumin 12-Hydroxystearic Acid in Triacetin Organogel for Topical Administration

Background: Curcumin (CUR) and its derivatives have shown a wide variety of biological activities, such as anti-oxidant, anti-inflammatory, anti-tumor, antimicrobial and antiparasitic effects as well as for the treatment of skin diseases. Due to its physico-chemical limitations such as low aqueous solubility and low bioavailability, we developed curcumin organogel as a topical delivery system to overcome those limitations. The12-hydroxystearic acid (12-HSA) is well known as a low-molecular-weight organogelators (LMOGs) capable of gelling an organic liquid phase. Different concentrations of (12-HSA) in triacetin with 50 mg CUR were gelled and applied for various examinations: tabletop rheology, oil binding capacity, pH measurement, spreadability, in vitro drug release, antibacterial activity and oscillatory rheology studies. The results revealed that the organogels transition temperatures from solid to liquid were greater than the normal body temperature, this helped the organogels keep their shape; they had good spreadability,and the organogels pH levels were within the safe range for the skin . In vitro release data showed that 4% 12HSA+5%CUR +TA (4TA) gave us 100% release after 6 hours. The selected 4TA illustrated good viscoelastic properties in the amplitude sweep test and a frequency-independent as seen in the frequency sweep test. CUR has good antibacterial action against Staphylococcus aureus; Streptococcus pyrogen, Proteus mirabilis, and Escherichia coli, which prevail at the site of wound injury as this pointed out that 4TA organogel can be used for topical wound healing.

Development and characterization of a topical gel, containing lavender (Lavandula angustifolia) oil loaded solid lipid nanoparticles

Gels loaded with nanocarriers offer interesting ways to create novel therapeutic approaches by fusing the benefits of gel and nanotechnology. Clinical studies indicate that lavender oil (Lav-O) has a positive impact on accelerating wound healing properly based on its antimicrobial and anti-inflammatory effects. Initially Lav-O loaded Solid Lipid Nanoparticles (Lav-SLN) were prepared incorporating cholesterol and lecithin natural lipids and prepared SLNs were characterized. Next, a 3% SLN containing topical gel (Lav-SLN-G) was formulated using Carbopol 940. Both Lav-SLN and Lav-SLN-G were assessed in terms antibacterial effects against S. aureus. Lav-SLNs revealed a particle size of 19.24 nm, zeta potential of -21.6 mv and EE% of 75.46%. Formulated topical gel presented an acceptable pH and texture properties. Minimum Inhibitory/Bactericidal Concentration (MIC/MBC) against S. aureus for LAv-O, Lav-SLN and Lav-SLN-G were 0.12 and 0.24 mgml− 1, 0.05 and 0.19 mgml− 1 and 0.045, 0.09 mgml− 1, respectively. Therefore, SLN can be considered as an antimicrobial potentiating nano-carrier for delivery of Lav-O as an antimicrobial and anti-inflammatory agent in topical gel.

In vitro study of the bactericidal activity for new derivatives of quaternary ammonium salts based on pyridoxine against gram-positive/gram-negative bacteria

Background: preventive care and successful treatment of infectious diseases (including hospital-acquired infections) are among the most important tasks of modern healthcare. There are not many effective antiseptics and disinfectants to solve this problem. Quaternary ammonium salts are currently one of the promising classes of disinfectants but their use is limited by the ability of microorganisms to develop resistance to these compounds. Modification of QAS with substituents of various natures is a possible way to solve this problem.&#x0D; Aims: in this work a bactericidal activity comparative analysis for two original quaternary ammonium compounds based on pyridoxine was carried out in comparison with benzalkonium chloride.&#x0D; Materials and methods: the bactericidal activity of 0.1% and 0.2% aqueous solutions of original QACs based on pyridoxine were studied against two widespread pathogens: S. aureus and E. coli. Antibacterial activity data were obtained using a standard in vitro test (bactericidal activity test on a metal surface, exposure time 1, 5 and 15 minutes). In addition to standard conditions, antibacterial efficacy was also studied under protein loading conditions (adding BSA solution to the surface).&#x0D; Results: for the studied compounds the RF (reduction factor - reduction lgCFU of microorganisms) was on average ≥ 3. Complicating the model conditions in the form of protein load led to a decrease in efficiency by 1-3 orders. We have also observed an interesting effect of exposure time-dependent specificity reversal to the S. aureus and E. coli.&#x0D; Conclusions: The obtained results showed high activity of the studied compounds (corresponding to the effectiveness criterion RF≥3 for commercial compounds used in this field).