Minimum Bactericidal Concentration Research Articles

Modulation of innate immunity related genes resulting in prophylactic antimicrobial and antiviral properties

BackgroundThe innate immunity acts during the early phases of infection and its failure in response to a multilayer network of co-infections is cause of immune system dysregulation. Epidemiological SARS-CoV-2 infections data, show that Influenza Virus (FLU-A-B-C) and Respiratory Syncytial Virus (RSV) are co-habiting those respiratory traits. These viruses, especially in children (mostly affected by ‘multi-system inflammatory syndrome in children’ [MIS-C] and the winter pandemic FLU), in the aged population, and in ‘fragile’ patients are causing alteration in immune response. Then, bacterial and fungal pathogens are also co-habiting the upper respiratory traits (e.g., Staphylococcus aureus and Candida albicans), thus contributing to morbidity in those COVID-19 affected patients.MethodsLiquid chromatography coupled with high-resolution mass spectrometry using the quadrupole orbital ion trap analyser (i.e., UHPLC-Q-Orbitrap HRMS) was adopted to measure the polyphenols content of a new nutraceutical formula (Solution-3). Viral infections with SARS-CoV-2 (EG.5), FLU-A and RSV-A viruses (as performed in BLS3 authorised laboratory) and real time RT-PCR (qPCR) assay were used to test the antiviral action of the nutraceutical formula. Dilution susceptibility tests have been used to estimate the minimum inhibitory and bactericidal concentration (MIC and MBC, respectively) of Solution-3 on a variety of microorganisms belonging to Gram positive/ negative bacteria and fungi. Transcriptomic data analyses and functional genomics (i.e., RNAseq and data mining), coupled to qPCR and ELISA assays have been used to investigate the mechanisms of action of the nutraceutical formula on those processes involved in innate immune response.ResultsHere, we have tested the combination of natural products containing higher amounts of polyphenols (i.e., propolis, Verbascum thapsus L., and Thymus vulgaris L.), together with the inorganic long chain polyphosphates ‘polyPs’ with antiviral, antibacterial, and antifungal behaviours, against SARS-CoV-2, FLU-A, RSV-A, Gram positive/ negative bacteria and fungi (i.e., Candida albicans). These components synergistically exert an immunomodulatory action by enhancing those processes involved in innate immune response (e.g., cytokines: IFNγ, TNFα, IL-10, IL-6/12; chemokines: CXCL1; antimicrobial peptides: HBD-2, LL-37; complement system: C3).ConclusionThe prophylactic antimicrobial success of this nutraceutical formula against SARS-CoV-2, FLU-A and RSV-A viruses, together with the common bacteria and fungi co-infections as present in human oral cavity, is expected to be valuable.

Earthworm Infusion as an Antimicrobial Against Bacteria Causing Diarrhea

Diarrhea is the second most common disease worldwide after Acute Respiratory Infection (ARI). One of the causes of diarrhea is the gastrointestinal infection caused by disease bacteria (microbe) such as Salmonella sp., Escherichia coli, Shigella sp., and Vibrio cholerae. The earthworm species Lubricus sp can be used as an alternative medication believed to be able to cure digestive diseases such as typhus, dysentery, and other indigestion like gastritis. This research is laboratory experimental research. The antibacterial activity is measured by determining the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) values of earthworm infusion (Lumbricus rubellus) using the tube dilution test. The bacteria used in this research are Escherichia coli, Shigella dysentriae, and Vibrio cholerae, isolated from the feces of diarrhea patients. This research aims to examine the earthworm infusion antibacterial (Lumbricus rubellus) activity to several bacteria that commonly cause diarrhea. The research results show that the average MIC value of earthworm infusion (Lumbricus rubellus) against Escherichia coli is >50%, Shigella dysentriae 0,098%, and Vibrio cholerae >50%. The average MBC value of earthworm infusion against Shigella dysentriae is 50%. .

Stability Studies of the Dilution Series of Different Antibiotic Stock Solutions in Culture Medium Incubated at 37 °C.

The long-term stability of antibiotics in culture media remains underexplored in scientific literature. This study evaluated the stability of eight distinct antibiotic stock solutions-amoxicillin, cefotaxime, neomycin, oxytetracycline, florfenicol, enrofloxacin, colistin, and potentiated sulfonamide-and their 10-fold dilution series in tryptone soy broth (TSB) at 37 °C, over 12 days. Samples were collected immediately after preparation and on days 1, 2, 5, 7, 9, and 12, with active substance concentrations measured using ultra-high-performance liquid chromatography (UHPLC) coupled with mass spectrometry. The results indicated that among the ultrapure water stock solutions, neomycin, florfenicol, and potentiated sulfonamide maintained stability (>95%). Within the culture medium, florfenicol showed consistent stability (100%) throughout the study, potentiated sulfonamide experienced minor degradation (>85%), and neomycin underwent significant degradation. Amoxicillin, oxytetracycline, and colistin displayed considerable degradation in both solution types but were more stable in ultrapure water solutions. The stability of cefotaxime and enrofloxacin in ultrapure water solutions and in the medium was very similar when compared; however, 3.6% of the former and 88.7% of the latter remained detectable by day 12. These findings are crucial for minimum inhibitory concentration (MIC) assessments, especially in minimum bactericidal concentration (MBC) studies, and in experiments concerning long-term evolution and co-selection. This study underscores the necessity of stability assessments in culture media to validate future experimental outcomes.

Antibacterial Effect, ADMET Properties, and Molecular Docking of Morpholine Derivatives with Varying Alkyl Chain Length Against Methicillin Resistant Staphylococcus aureus (MRSA) Isolates

AbstractIn this work, we synthesized a series of nine tetraalkylammonium salts derived from N‐methyl morpholine and assessed their antibacterial efficacy against Methicillin‐Resistant Staphylococcus aureus (MRSA). The investigated morpholinium cations differ by the length of one linear alkyl chain, which ranges from 1 to 18 carbon atoms. We found that compounds with alkyl chains in the n‐C12H25‐(n‐dodecyl) to C16H33‐(n‐hexadecyl) display the highest bactericidal effects, exhibiting Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) values of 3.9 μg/mL – surpassing the effectiveness of the commercial drug Linezolid. Conversely, compounds with shorter chains (<5 carbon atoms) are inactive against MRSA, establishing a clear structure‐activity relationship. Assays on A. salina reveal that short‐alkyl‐chain morpholinium derivatives, inactive against MRSA), are moderately toxic, while the strongest bactericides of our set demonstrate high or extreme toxicity to A. salina. Our findings underscore the potential of morpholine derivatives as a means to control Methicillin‐Resistant Staphylococcus aureus and pinpoint the need to develop safe applications for these compounds given their potential toxicity.

Biosorption of copper, nickel, and manganese as well as the production of metal nanoparticles by Bacillus species isolated from soils contaminated with electronic wastes.

Improper electronic waste management in the world especially in developing countries such as Iran has resulted in environmental pollution. Copper, nickel, and manganese are from the most concerned soil contaminating heavy metals which found in many electronic devices that are not properly processed. The aim of this study was to investigate the biological removal of copper, nickel, and manganese by Bacillus species isolated from a landfill of electronic waste (Zainal Pass hills located in Isfahan, Iran) which is the and to produce nanoparticles from the studied metals by the isolated bacteria. The amounts of copper, nickel, and manganese in the soil was measured as 1.9 × 104 mg/kg, 0.011 × 104 mg/kg and 0.013 × 104 mg/kg, respectively based on ICP-OES analysis, which was significantly higher than normal (0.02 mg/kg, 0.05 mg/kg, and 2 mg/kg, respectively. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of metals on the bacterial isolates was determined. The biosorption of metals by the bacteria was evaluated by inductively coupled plasma optical emission spectroscopy (ICP-OES). The metal nanoparticles were synthetized utilizing the isolates in culture media containing the heavy metals with the concentrations to which the isolates had shown resistance. X ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) were used for the evaluation of the fabrication of the produced metal nanoparticles. Based on the findings of this study, a total of 15 bacterial isolates were obtained from the soil samples. The obtained MICs of copper, nickel, and manganese on the isolates were 40-300 mM, 4-10 mM, and 60-120 mM, respectively. The most resistant isolates to copper were FM1 and FM2 which were able to bio-remove 79.81% and 68.69% of the metal, respectively. FM4 and FM5 were respectively the most resistant isolate to nickel and manganese and were able to bio-remove 86.74% and 91.96% of the metals, respectively. FM1, FM2, FM4, and FM5 was molecularly identified as Bacillus cereus, Bacillus thuringiensis, Bacillus paramycoides, and Bacillus wiedmannii, respectively. The results of XRD, SEM and EDS showed conversion of the copper and manganese into spherical and oval nanoparticles with the approximate sizes of 20-40 nm. Due to the fact that the novel strains in this study showed high resistance to copper, nickel, and manganese and high adsorption of the metals, they can be used in the future, as suitable strains for the bio-removal of these metals from electronic and other industrial wastes.

Antibacterial and antibiofilm activity of mint leaves (Mentha piperita L) extracts against Streptococcus mutans UA159: a laboratory experiment

Introduction: Oral health is a major concern in healthcare worldwide, with dental caries being a prevalent issue among children and adults. Streptococcus mutans is a primary bacterium implicated in the development of dental caries due to its acidogenic nature. Mint leaf (Mentha piperita L.) is a unique herbal plant that has antibacterial and antibiofilm properties against S. mutans and minimal side effects. The purpose of this study was to analyze the antibacterial effectiveness of mint leaf against the growth of S. mutans UA159 and its antibiofilm effects. Methods: This study was conducted experimentally with the posttest-only control group design, using the broth microdilution method in 6 test groups, namely mint leaf extract with a concentration of 3.125, 6.25, 12.5, 25, 50, and 100% and also two control groups, namely the negative control using aquadest and the positive control using 0.2% chlorhexidine. Biofilm growth is determined by comparing Optical Density (OD) values and then calculating the percentage of eradication of S. mutans biofilm formation. Results: The results indicated that the mint leaf extract exhibited antibacterial effects against S. mutans, with the largest inhibition zone diameter observed at a 100% concentration. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC)90 values using the broth microdilution method in this study were 12.5% and 100% concentrations, respectively. Mint leaf extract has been shown to significantly inhibit the growth of S. mutans (p<0.05). The results of the inhibition test on biofilm formation at a concentration of 100% averaged 87.39%. Conclusion: Mint leaf extract has an antibacterial and antibiofilm effect on the growth of S. mutans. The level of inhibition of mint leaf extract on the growth of S. mutans is proportional to its concentration; the higher the concentration of the extract, the stronger the inhibitory ability.KeywordAnti-Bacterial agents, biofilms, Mentha piperita, oral health, Streptococcus mutans.

Biosynthesis of zinc oxide nanoparticles using water hyacinth extracts: Characterization, evaluation of antimicrobial and dye removal

In nanobiotechnology, synthesizing metal nanoparticles (NPs) using plant extracts has recently been increasing because of eco-friendly and low-cost methods. For this work, zinc oxide nanoparticles (ZnO NPs) have been synthesized by biosynthesis process using water hyacinth extracts (WHE). The water hyacinth (WH) was chosen because the WH is fast-growing and the most toxic aquatic plant in the world. Therefore, this work aims to apply these WHE to be a precursor in the biosynthesis of ZnO NPs (ZnOBio-NPs) based on the research of a sustainable environment. The ZnO NPs synthesized by the WHE were investigated for their antibacterial and photocatalytic activities. An UV-Vis spectrum showed a specific absorbance peak around 362 nm with an average band gap of 3.22 eV. As the result, TEM analysis revealed a triangle structure with an average size of about 64.05 nm. The peaks of XRD analysis show a hexagonal wurtzite structure. The ZnO NPs synthesized by the WHE showed higher antibacterial activity against S. aureus better than E. coli. It is interesting to note that the ZnOBio-NPs synthesized from the WHE can have an anti P. acnes (JB7) with a minimum inhibitory concentration (MIC) and a minimum bactericidal concentration (MBC) equal to 50 µg∙mL‒1 and 200 µg∙mL‒1, respectively. In addition, the ZnOBio-NPs also can effectively remove more than 90% of the malachite green within 180 minutes with extremely high reuse.

Mechanisms of Triton X-100 reducing the Ag+-resistance of Enterococcus faecalis.

To investigate the mechanism of Triton X-100 (TX-100) reducing the Ag+-resistance of Enterococcus faecalis (E. faecalis), and evaluate the antibacterial effect of TX-100+Ag+ against the induced Ag+-resistant E. faecalis (AREf). The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of AgNO3 against E. faecalis with/without TX-100 were determined to verify the enhanced antibacterial activity. Transmission electron microscopy (TEM) was used to observe the morphological changes of E. faecalis after treatment. The intra- and extracellular concentration of Ag+ in treated E. faecalis was evaluated using inductively coupled plasma mass spectrometer (ICP-MS). The changes in cell membrane potential and integrity of treated E. faecalis were also observed using the flow cytometer. Moreover, AREf was induced through continuous exposure to sub-MIC of Ag+ and the antibacterial effect of TX-100+Ag+ on AREf was further evaluated. The addition of 0.04% TX-100 showed maximal enhanced antibacterial effect of Ag+ against E. faecalis. The TEM and ICP-MS results demonstrated that TX-100 could facilitate Ag+ to enter E. faecalis through changing the membrane structure and integrity. Flow cytometry further showed the effect of TX-100 on membrane potential and permeability of E. faecalis. In addition, the enhanced antibacterial effect of TX-100+Ag+ was also confirmed on induced AREf. TX-100 can facilitate Ag+ to enter E. faecalis through disrupting the membrane structure and changing the membrane potential and permeability, thus reducing the Ag+-resistance of E. faecalis and enhancing the antibacterial effect against either normal E. faecalis or induced AREf.

Development of silver-doped copper oxide and chitosan nanocomposites for enhanced antimicrobial activities.

Antimicrobial resistance (AMR) has emerged as a significant and pressing public health concern, posing serious challenges to effectively preventing and treating persistent diseases. Despite various efforts made in recent years to address this problem, the global trends of AMR continue to escalate without any indication of decline. As AMR is well-known for antibiotics, developing new materials such as metal containing compounds with different mechanisms of action is crucial to effectively address this challenge. Copper, silver, and chitosan in various forms have demonstrated significant biological activities and hold promise for applications in medicine and biotechnology. Exploring the biological properties of these nanoparticles is essential for innovative therapeutic approaches in treating bacterial and fungal infections, cancer, and other diseases. To this end, the present study aimed to synthesize silver@copper oxide (Ag@CuO) nanoparticles and its chitosan nanocomposite (Chi-Ag@CuO) to investigate their antimicrobial efficacy. Various established spectroscopic and microscopic methods were employed for characterization purposes, encompassing scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Subsequently, the antimicrobial activity of the nanoparticles was assessed through MIC (minimum inhibitory concentration), MBC (minimum bactericidal concentration), and well-disk diffusion assays against Pseudomonas aeruginosa, Acinetobacter baumannii Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans. The size of the CuO-NPs, Ag@CuO, and Chi-Ag@CuO NPs was found to be 70-120 nm with a spherical shape and an almost uniform distribution. The nanocomposites were found to possess a minimum inhibitory concentration (MIC) of 5 μg/mL and a minimum bactericidal concentration (MBC) of 250 μg/mL. Moreover, these nanocomposites generated varying clear inhibition zones, with diameters ranging from a minimum of 9±0.5 mm to a maximum of 25±0.5 mm. Consequently, it is evident that the amalgamation of copper-silver-chitosan nanoparticles has exhibited noteworthy antimicrobial properties in the controlled laboratory environment, surpassing the performance of other types of nanoparticles.

Assessment of antibacterial activity, modes of action, and synergistic effects of Origanum vulgare hydroethanolic extract with antibiotics against avian pathogenic Escherichia coli

This study evaluates the antibacterial effectiveness of Origanum vulgare hydroethanolic extract, both independently and in combination with antibiotics, against Escherichia coli strains associated with avian colibacillosis—a significant concern for the poultry industry due to the rise of antibiotic-resistant E. coli. The urgent demand for new treatments is addressed by analyzing the extract's phytochemical makeup via High-Performance Liquid Chromatography (HPLC), which identified sixteen phenolic compounds. Antibacterial activity was determined through agar diffusion and the measurement of minimum inhibitory and bactericidal concentrations (MIC and MBC), showing moderate efficacy (MIC: 3.9 to 7.8 mg/mL, MBC: 31.2 to 62.4 mg/mL). Combining the extract with antibiotics like ampicillin and tetracycline amplified antibacterial activity, indicating a synergistic effect and highlighting the importance of combinatory treatments against resistant strains. Further analysis revealed the extract's mechanisms of action include disrupting bacterial cell membrane integrity and inhibiting ATPase/H+ proton pumps, essential for bacterial survival.Moreover, the extract effectively inhibited and eradicated biofilms, crucial for preventing bacterial colonization. Regarding cytotoxicity, the extract showed no hemolytic effect at 1 to 9 mg/mL concentrations. These results suggest Origanum vulgare extract, particularly when used with antibiotics, offers a promising strategy for managing avian colibacillosis, providing both direct antibacterial benefits and moderating antibiotic resistance, thus potentially reducing the economic impact of the disease on the poultry industry.

Synergistic antioxidant and antibacterial activities of polyphenol extracts from mangosteen peels in preservation of Pangasius hypophthalmus fish balls

In recent years, natural preservatives have attracted more and more attention in food processing since they can enhance food shelf-life and safety. In this study, the polyphenol extract was obtained from mangosteen peels using enzyme-microwave assisted method, characterized for its antioxidant and antimicrobial activities and subsequently used as a natural additive in fish ball preservation. Results revealed that the mangosteen peel polyphenol powder (MPP) had a high phenolic content of 154 mg gallic acid equivalent/g dry matter, which led to high 2,2-diphenyl-1-picrylhydrazyl free radical scavenging capacity of 95 mg Trolox equivalent/g dry matter. MPP also exhibited effective antimicrobial activity against E. coli and S. aureus, expressed by its large inhibitory zones (11.3 and 12.1 mm, respectively) and small ratios (less than 4) of minimum bactericidal concentration over minimum inhibitory concentration against tested bacteria. The MPP supplementation at the levels of 38 mg/100 g and 53 mg/100 g into fish balls remarkably improved their gel strength, reduced lipid oxidation, limited protein oxidation and structural degradation as compared to those of the control without any addition or with synthetic preservatives. Especially, the addition of 53 mg MPP/100 g could sufficiently retard the microorganism growth. The synergistic effects of MPP in both antioxidant and antimicrobial activities hence could extend the shelf-life of fish balls, more than 40 %, as compared to butylated hydroxytoluene (synthetic antioxidant) or sodium benzoate (synthetic antimicrobial) with their single effects. These findings imply that MPP could be potentially used as a natural additive in preservation of fish and meat products.

Antibacterial and antibiofilm efficacy of Solanum lasiocarpum root extract synthesized silver/silver chloride nanoparticles against Staphylococcus haemolyticus associated with bovine mastitis

Staphylococcus haemolyticus is a cause of bovine mastitis, leading to inflammation in the mammary gland. This bacterial infection adversely affects animal health, reducing milk quality and yield. Its emergence has been widely reported, representing a significant economic loss for dairy farms. Interestingly, S. haemolyticus exhibits higher levels of antimicrobial resistance than other coagulase-negative Staphylococci. In this study, we synthesized silver/silver chloride nanoparticles (Ag/AgCl-NPs) using Solanum lasiocarpum root extract and evaluated their antibacterial and antibiofilm activities against S. haemolyticus. The formation of the Ag/AgCl-NPs was confirmed using UV–visible spectroscopy, which revealed maximum absorption at 419 nm. X-ray diffraction (XRD) analysis demonstrated the crystalline nature of the Ag/AgCl-NPs, exhibiting a face-centered cubic lattice. Fourier transform infrared (FT-IR) spectroscopy elucidated the functional groups potentially involved in the Ag/AgCl-NPs synthesis. Transmission electron microscopy (TEM) analysis revealed that the average particle size of the Ag/AgCl-NPs was 10 nm. Antimicrobial activity results indicated that the minimum inhibitory concentration (MIC) and maximum bactericidal concentration (MBC) of the Ag/AgCl-NPs treatment were 7.82–15.63 μg/mL towards S. haemolyticus. Morphological changes in bacterial cells treated with the Ag/AgCl-NPs were observed under scanning electron microscopy (SEM). The Ag/AgCl-NPs reduced both the biomass of biofilm formation and preformed biofilm by approximately 20.24–94.66 % and 13.67–88.48 %. Bacterial viability within biofilm formation and preformed biofilm was reduced by approximately 21.56–77.54 % and 18.9–71.48 %, respectively. This study provides evidence of the potential of the synthesized Ag/AgCl-NPs as an antibacterial and antibiofilm agent against S. haemolyticus.

Anatural approach tocombating antibiotic-resistant pathogens inlivestock: Hibiscus sabdariffa-derived hibiscus acid asapromising solution.

Weexamined the antibacterial efficacy ofstreptomycin, hibiscus acid, and their combination against multidrug-resistant Shiga-toxin-producing Escherichia coli (STEC) and Salmonella Typhimurium inmice. Wedetermined the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for streptomycin, hibiscus acid, and their combination against STEC and Salmonella. Fifteen sets ofsix mice ineach set were utilised: six groups were orally exposed to4log10 colony forming units (CFUs) ofS.Typhimurium and another six toSTEC, and three acted asthe controls. Six hours post-inoculation, specific groups ofmice received either oral solutions containing hibiscus acid at5 and 7mg/ml; streptomycin at50 and 450μg/ml; hibiscus acid/streptomycin (5mg/ml hibiscus acid and 50μg/ml streptomycin); orisotonic saline. The study determined the MIC and MBC of7mg/ml ofhibiscus acid; 300 and 450μg/ml ofstreptomycin; and two concentrations ofhibiscus/streptomycin (3mg/ml/ 20μg/ml and 5mg/ml/ 50μg/ml). Interestingly, the mice that were infected and subsequently treated with hibiscus acid at7mg/ml alone orin conjunction with streptomycin did not have either STEC orSalmonella intheir faecal samples, and none ofthe mice died. Incontrast, the untreated mice and those exclusively treated with streptomycin had the pathogens present intheir stool, leading tothe mortality ofall the subjects.

The antimicrobial effectiveness of chlorhexidine and chlorhexidine-silver sulfadiazine-impregnated central venous catheters against the emerging fungal pathogen Candida auris

Candida auris is an emerging multidrug-resistant fungus associated with catheter-related bloodstream infections. In vitro efficacy of chlorhexidine (CHX) and CHX-silver sulfadiazine-impregnated (CHX-S) antimicrobial central venous catheters (CVCs) against C auris was investigated. Minimum inhibitory and bactericidal CHX concentrations were determined against 19 C auris isolates. To assess extraluminal efficacy, segments from CVCs impregnated externally (CHX-S1) and both externally and internally (CHX-S2) were plasma-conditioned for 1- and 6-day, and to assess intraluminal efficacy, CHX-S2 CVCs were preconditioned with saline-lock for 6days, followed by 24-hour C auris inoculation and microbial adherence determination on impregnated and nonimpregnated CVCs. CHX inhibited all C auris isolates with minimum inhibitory and bactericidal concentrations range of 8 to 128μg/mL. C auris adherence was reduced on CHX-S1 and CHX-S2 extraluminally by 100% on day 1, 86.96% to 100% on day 7, and intraluminally on CHX-S2 by 56.86% to 90.52% on day 7. CHX and CHX-S CVCperformance against C auris observed in this study is consistent with antimicrobial benefits observed in prior preclinical and randomized controlled clinical studies. CHX showed strong inhibitory and cidal effects on C auris. CHX-S CVCs proved highly efficacious against this pathogen under in vitro conditions. Additional studies, however, are required to confirm clinical benefit.

Design, Synthesis and In vitro Screening of Novel 2-Mercaptobenzothiazole- Clubbed Phenylacetamides as Potential Antibacterial Agents

Background: The frightening rise of bacterial resistance is occurring worldwide and endangering the efficacy of antibiotics. Hence, the development of novel and potent antibacterial is a need of the day. Objective: In this study, we designed and synthesized compounds C1-C11. These compounds are characterized by their FT-IR, NMR and MS spectral data and examined in vitro for their antibacterial activity. Methods: Compounds C1-C11 were synthesized by reacting 2-mercaptobenzothiazole with appropriate chloroacetamide in the presence of anhydrous potassium carbonate and dry acetone at room temperature. To assess the antibacterial activity, minimum inhibitory and minimum bactericidal concentrations were examined by broth microdilution method against the selected strains of both Gram-positive and Gramnegative bacteria. Time-kill kinetics study was also performed as per CLSI guidelines. Results: Compounds C6 and C7 displayed promising activity against Staphylococcus aureus ATCC 43300 with MICs of 9.43 and 7.73 μM, respectively. These two compounds also displayed promising antibacterial activity against S. aureus 5021 with MIC values of 7.53 and 9.68 μM, respectively. In MBC determination, these two compounds (tested in the concentration range of 7.53 to 262.3 μM) displayed bactericidal activity against methicillin resistant S. aureus ATCC 43300, S. aureus NCIM 5021 and S. aureus NCIM 5022. In time-kill kinetics study, compounds C6 and C7 also exhibited bactericidal activity against S. aureus NCIM 5021 and S. aureus ATCC 43300 after 12 h of exposure. In general, all tested compounds exhibited poor activity against Mycobacterium sp. NCIM 2984 and also against tested Gramnegative bacteria Klebsiella pneumoniae NCIM 2706, Escherichia coli NCIM 2065 and Pseudomonas aeruginosa NCIM 2036. Further, computed ADMET properties of C1-C11 showed a favourable pharmacokinetic profile with zero violation of Lipinski’s rule of five. Conclusion: The result showed that in phenylacetamides C6 and C7 presence of phenyl ring substituted with -CF3 group is responsible for their high antibacterial activity against S. aureus ATCC 43300 (MICs, 9.43 and 7.73 μM, respectively). These two compounds also exhibited bactericidal activity respectively against S. aureus NCIM 5021 in time kill kinetics study.

Synthesis, Characterization, and Antibacterial Activity of Plant-Derived Zinc Oxide Nanostructure Using <i>Lavandula angustifolia</i> and <i>Phyllanthus niruri</i> Extracts

In recent years, green synthesized nanomaterials have garnered wide interest due to its inherent features like rapidity, cost-effectiveness, and environmentally friendly technique. The green synthesis of Zinc oxide nanostructures (n-ZnO) using two kinds of plant extract, lavender (Lavandula angustifolia) and meniran (Phyllanthus niruri), were discussed and their antibacterial activities were compared. Characterization by means of X-ray diffraction (XRD), Fourier transform infrared (FTIR), and field emission-scanning electron microscopy/energy dispersive X-ray spectroscopy (FE-SEM/EDS) were used to confirm the successful formation of n-ZnO using both plant extracts. The antibacterial activity of the n-ZnO synthesized from two different plant extracts was tested against Klebsiella pneumoniae and methicillin-resistant Staphylococcus aureus (MRSA). The results show that both n-ZnO has antibacterial activity against MRSA. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values for n-ZnO synthesized from meniran extract were 78 and 156 mg/mL, respectively, while MIC and MBC values for n-ZnO synthesized from lavender extract were 156 and 312 mg/mL, respectively. These results confirm that the n-ZnO prepared from meniran extract is more effective in inhibiting MRSA than the n-ZnO prepared from lavender extract. This study proves that plant-based n-ZnO has anti-microbial activities and may serve as antimicrobial therapeutics.

Botanical Extracts and Compounds of Castanea Plants and Methods of Use: US20190125818A1 - The United States Patent Evaluation.

Bacterial infections are increasingly difficult to combat, which makes them a threat to public health on a global level. Staphylococcus aureus is considered one of the main causes of infections in hospitals, as it has a variety of virulence factors, as well as is able to produce bacterial biofilms, which, consequently, bring numerous damages to public health as a result of increased resistance to conventional antibiotics and a longer hospital stay. Therefore, the use of compounds extracted from medicinal plants is a potential pharmaceutically acceptable target, as they do not have toxicity and the potential to disrupt biofilms produced by Staphylococcus aureus already evidenced, thus revealing their relevance to our study. The objective of this work was to perform a critical analysis of a patent with natural extracts against bacterial biofilms found in the United States Patent and Trademark Office (USPTO) database, to map the possible bioactive compounds that may serve as potential future antimicrobial drugs. A technological survey was carried out to verify existing patents using natural extracts with anti-biofilm potential. For this, it was searched with the keywords: Botanical extracts AND biofilms; which were performed in the United States Patent and Trademark Office (USPTO) database. Thus, the selected patent used a non-aqueous extract partitioned and vacuum-contracted, subsequently lyophilized for assays with antimicrobial potential. Because of this, a patent was analyzed regarding its chemistry, and biological activity, followed by a critical analysis of the technology proposed in the invention. When using the keywords Botanical extracts AND biofilms in the USPTO, it was possible to find twenty-two inventions; however, only four patents in the USPTO were in agreement with the proposal of the natural extract having antimicrobial activity and an anti-biofilm potential, of which two belonged to the same applicant with similar proposals. The key point of this invention was to enable the compounds of the Castanea sativa plant and its methods of obtaining the extract to present a significant antimicrobial action associated or not with antibiotics, promoting the development of new therapies against bacterial infections capable of disrupting biofilms. The invention developed a methodology for extracting Castanea sativa, in which pentacyclic triterpene compounds were found mostly in its leaves. Whereas for the extraction, the crude methanol extracts called extracts 224 from the ground leaves were made by maceration, filtered, combined, concentrated under pressure in rotary evaporators, and lyophilized. After that, they were resuspended in water and partitioned in succession with hexane, ethyl acetate, and butanol. The most active refined partition was the 224C extract with the solvent ethyl acetate, which was subjected to further fractionation using silica column chromatography. Resulting in the most refined extract, which was 224C-F2, capable of acting directly on the quorum sensing of bacteria, mainly Staphylococcus aureus, blocking the translation of RNAIII, including a series of exotoxins. Regarding the antimicrobial capacity against Staphylococcus aureus, it presented Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of 1.56 μg/mL-1 and > 100 μg/mL -1, respectively. Given the analyzed patent, it was possible to verify the importance of alternatives to reduce the impact of bacterial biofilms, which causes damage to industries in general and to health. From this, the invention analyzed has a promising proposal with antimicrobial potential focusing on the great impact of bacterial biofilms. Therefore, natural extracts with antibiofilmic potential can help to minimize the economic losses caused to health due to these multidrug-resistant microorganisms with different virulence mechanisms.

Disinfectant efficacy of glabridin against dried and biofilm cells of Listeria monocytogenes and the impact of residual organic matter

Glabridin is an antimicrobial compound which can be extracted from plants, such as liquorice (Glycyrrhiza glabra) roots. Although its activity against food-borne pathogens and spoilage microorganisms has already been reported, the investigation of potential applications as a surface disinfectant is still largely unexplored. Hence, this study evaluated the disinfectant efficacy of glabridin against Listeria monocytogenes. The activity of glabridin was first tested in vitro in a nutrient-rich medium against eight strains of L. monocytogenes, including food isolates and the model strain EGDe. The tested strains showed similar susceptibility with minimal inhibitory and bactericidal concentrations of 12.5 µg/mL and 25 µg/mL, respectively. Subsequently, L. monocytogenes L6, FBR17 and EGDe were selected to assess the efficacy of glabridin against dried cells (according to the European standard EN 13697:2015 + A1:2019) and biofilm cells on stainless steel surfaces. Moreover, the impact of food residual organic matter was investigated using skim milk, cantaloupe and smoked salmon solution as soiling components. Our results showed that applying 200 µg/mL of glabridin resulted in a substantial reduction (>3 log10) of dried and biofilm cells of L. monocytogenes in standard conditions (i.e. low level of residual organic matter). Cantaloupe soiling components slightly reduced the activity of glabridin, while the efficacy of glabridin when tested with salmon and skim milk residuals was substantially affected. Comparative analysis using standardized protein contents provided evidence that the type of food matrices and type of proteins may impact the activity of glabridin as a disinfectant. Overall, this study showed low strain variability for the activity of glabridin against L. monocytogenes and shed light on the possible application of this natural antimicrobial compound as a surface disinfectant.

Insight into the antibacterial properties of terpinen-4-ol on planktonic growth and biofilm-formation of Vibrio parahaemolyticus

Vibrio parahaemolyticus outbreaks emphasize the urgency of highly efficient prevention strategies to control this foodborne pathogen. This study investigated the antibacterial effects of terpinen-4-ol on V. parahaemolyticus RIMD2210633 and explored the underlying mechanism via RNA-seq analysis. The results showed that terpinen-4-ol inhibited V. parahaemolyticus efficiently with minimum inhibitory concentration and minimum bactericidal concentration values at 0.8 μL/mL. Scanning electron microscopy and PI/SYTO 9 staining assay demonstrated that cell morphology and cell membrane integrity were dose-dependently destructed. Additionally, biofilm formation was significantly inhibited according to crystal violet and MTT assay analysis. Notably, terpinen-4-ol showed good inhibitory activity against V. parahaemolyticus on salmon fillets via fumigation at 4 °C. Transcriptional analysis revealed significant downregulation of genes participated in cell wall formation (oppB, oppF), cell membrane integrity, pilus assembly protein, biofilm formation and cell motility (ToxR , LuxR), capsular polysaccharide biosynthesis protein, type IV pilin MshA and mannose-sensitive haemagglutinin type-IV pili (MSHA) biogenesis protein (MshJ, MshJ, MshK, MshL, MshN). The results demonstrated that terpinen-4-ol can efficiently inhibit the growth and pathogenicity of V. parahaemolyticus. With its safety and pleasant odor, terpinen-4-ol can be developed as a natural antibacterial substance to tackle V. parahaemolyticus contamination in food preservation and prevent associated diseases.

Development of apple pectin/soy protein isolate-based edible films containing punicalagin for strawberry preservation

In this study, we developed punicalagin-loaded antimicrobial films based on soy protein isolate (SPI) and apple pectin (AP). The AP was derived from apple pomace waste while the punicalagin was obtained from pomegranate peel. Punicalagin was identified to exist in both α- and β-isomers, with the β-type being predominant. The composite films were characterized using scanning electron microscopy, Fourier transformed infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis. Our results demonstrated that the incorporation of AP significantly enhanced the mechanical strength, heat resistance, and barrier properties of the films. Moreover, the composite films integrated with punicalagin exhibited excellent antimicrobial activities against Staphylococcus aureus (with a minimum bactericidal concentration value of 0.25 %), Escherichia coli (with a minimum bactericidal concentration value of 0.50 %), and Aspergillus niger. Finally, these antimicrobial film solutions were tested as coatings on strawberries and found to have significantly better effects on reducing weight loss, improving shelf-life, and maintaining the freshness of strawberries compared to coatings without punicalagin. The results indicate that antimicrobial coatings loaded with punicalagin hold great promise as multifunctional active packaging materials for fruit preservation.