Indifferent Effect Research Articles

Synergistic Antibacterial Effects of Areca Nut Seed (Areca catechu L.) and Binahong leaf (Anredera cordifolia (Ten.) Steenis) Extracts Against Propionibacterium acnes

Areca nut (Areca catechu L.) seeds has antibacterial properties due to their alkaloid, flavonoid, tannin, saponin, and polyphenol compounds. Binahong leaves (Anredera cordifolia (Ten.) Steenis) contain flavonoids, polyphenols, saponins, and alkaloids that also act as antibacterial agents. This study aimed to assess the antibacterial activity and synergistic effects of combining extracts from areca nut and binahong leaves against Propionibacterium acnes. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of P. acnes were evaluated for the ethanol extracts of areca nut and binahong leaves. The MIC and MBC values 400 ppm and 1.600 for extract ethanol single areca nut and 50.000 ppm and 100.000 ppm for binahong leaves. The MIC and MBC values for the combination 400/12.500 ppm and 1.600/781,25 ppm for areca nut and 50,000/800 ppm and 100,000/100 ppm for binahong leaves, respectively. The synergy between the two extracts was determined using the Fractional Inhibitory Concentration Index (FICI). The FICI value of 1. P. acnes indicates an indifferent effect (1 < FICI ≤ 4).

In vitro and silico Analysis of Amentoflavone against Candida albicans with a Competitive Action about Amphotericin B

Introduction: Antifungal resistance is a global health problem, and alternatives for control and treatment must be sought. Thus, substances isolated from plants with antifungal capacity have received considerable attention in the pharmaceutical sector. Ouratea fieldingiana, popularly known as batiputá, is a tree species found in northeastern Brazil, with its leaves rich in biflavonoids such as amentoflavone. Biflavonoids are well-studied due to their high antifungal capacity. Objectives: Carry out the isolation, identification, and characterization of the compound amentoflavone (AMT), as well as evaluate its antifungal activity and modulatory effect against strains of Candida albicans, also including the computational study of the mechanism of action of the compound AMT against the Als3 and Sap5 enzymes of C. albicans. Methodology: Column chromatography was used to isolate the AMT compound from the species O. fieldingiana, and its characterization was performed by high-performance liquid chromatography (HPLC). The antifungal activity was analyzed by the broth microdilution method. Modulatory activity assays were performed by the checkerboard technique using AMT and amphotericin B (AmB) as a standard. For the in silico study, computational simulations of the interaction between the enzymes Als3 and Sap5, and AMT were performed using the Vina AutoDock Code. Results: The AMT compound showed an inhibitory effect against all strains of C. albicans. Regarding modulatory activity, an indifferent and antagonistic effect was observed for all C. albicans strains tested. Molecular docking with AMT showed higher affinity energy for the Als3 and Sap5 enzymes than AmB. The results obtained in this study suggest that AMT has antifungal effects, as well as a high affinity for the Als3 and Sap5 enzymes of C. albicans. Conclusion: These results prove that the AMT compound could be a potential source of a new biotechnological product, acting as a natural antifungal agent.

The effect of combinations of a glyphosate-based herbicide with various clinically used antibiotics on phenotypic traits of Gram-negative species from the ESKAPEE group

The emission of glyphosate and antibiotic residues from human activities threatens the diversity and functioning of the microbial community. This study examines the impact of a glyphosate-based herbicide (GBH) and common antibiotics on Gram-negative bacteria within the ESKAPEE group (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp. and Escherichia coli). Ten strains, including type and multidrug-resistant strains for each species were analysed and eight antibiotics (cefotaxime, meropenem, aztreonam, ciprofloxacin, gentamicin, tigecycline, sulfamethoxazole-trimethoprim, and colistin) were combined with the GBH. While most combinations yielded additive or indifferent effects in 70 associations, antagonistic effects were observed with ciprofloxacin and gentamicin in five strains. GBH notably decreased the minimum inhibitory concentration of colistin in eight strains and displayed synergistic activity with meropenem against metallo-β-lactamase (MBL)-producing strains. Investigation into the effect of GBH properties on outer membrane permeability involved exposing strains to a combination of this GBH and vancomycin. Results indicated that GBH rendered strains sensitive to vancomycin, which is typically ineffective against Gram-negative bacteria. Furthermore, we examined the impact of GBH in combination with three carbapenem agents on 14 strains exhibiting varying carbapenem-resistance mechanisms to assess its effect on carbapenemase activity. The GBH efficiently inhibited MBL activity, demonstrating similar effects to EDTA (ethylenediaminetetraacetic acid). Chelating effect of GBH may have multifaceted impacts on bacterial cells, potentially by increasing outer membrane permeability and inactivating metalloenzyme activity.

Chemical composition and antibacterial activity of essential oils extracted from fresh and dried aerial parts of Rosmarinus officinalis L. Pistacia lentiscus L. and Thymus vulgaris L. from Algeria

ABSTRACT The aim of this study was to determine the chemical composition and antibacterial activity of essential oils (EOs) extracted from local plant by steam distillation from the aerial parts (fresh – dried) of rosemary (Rosmarinus officinalis L.), pistachio (Pistacia lentiscus L.) and thyme (Thymus vulgaris L.). Monoterpenes were identified by GC-MS as main compounds, namely 1,8-cineole (34.5–35 %), α-pinene (36.2–36.6 %) and thymol (42.2–42.1 %). Our results showed that EOs tested had antibacterial effects at different levels, with MICs ranging from 1.56 to 6.25 mg.mL−1. Fresh rosemary EO was synergistic against Pseudomonas aeruginosa ATCC 27,853 when combined with dried rosemary EO and fresh pistachio EO, with MICs half those of oils alone (from 6.25 to 3.12 mg.mL−1). In addition, antagonistic, additive and indifferent effects were recorded at 1 %, 3 % and 93 %, respectively. Our findings provide new data on antimicrobial potential of local plants and possibilities of their use as food preservatives.

Inhibitory effects of potassium sorbate and ZnO nanoparticles on Escherichia coli and Staphylococcus aureus in milk-based beverage

Antibacterial substances have played a crucial role in food preservation. Herein, the inhibitory effects of potassium sorbate and ZnO nanoparticles (ZnO NPs) on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) in milk-based beverages were examined through the determination of their minimum inhibitory concentrations (MICs) with an automated method for measuring bacterial growth curves. We revealed that the MICs of potassium sorbate and ZnO NPs against E. coli were 16.0 mg/mL and 8.0 mg/mL, respectively. While against S. aureus they were 24.0 mg/mL and 8.0 mg/mL, respectively. ZnO NPs demonstrated higher antibacterial efficacy compared to potassium sorbate. The combination of potassium sorbate and ZnO NPs showed an indifferent effect on E. coli, but an additive effect on S. aureus. The addition of 3 × MIC of either potassium sorbate or ZnO NPs resulted in a complete suppression of bacterial growth for 5 days. This study underscored the efficacy of potassium sorbate and ZnO NPs, either alone or in combination, in combating E. coli and S. aureus, highlighting their potential commercial utility in safeguarding milk-based beverages from spoilage.

Selective in vitro Synergistic Evaluation of Probiotic Tolerant morpholinyl- and 4-ethylpiperazinyl-Imidazole-chalcone Derivatives on Gastrointestinal System Pathogens

Imidazole-chalcone compounds are recognised for their broad-spectrum antimicrobial properties. Probiotic-friendly, selective new-generation antimicrobials prove to be more efficient in combating gastrointestinal system pathogens. The aim of this study is to identify imidazole-chalcone derivatives that probiotics tolerate and evaluate their in vitro synergistic antimicrobial effects on pathogens. In this study, fifteen previously identified imidazole-chalcone derivatives were analyzed for their in vitro antimicrobial properties against gastrointestinal microorganisms. Initially, the antimicrobial activity of pathogens was measured using the agar well diffusion method, while the susceptibility of probiotics was determined by microdilution. The chosen imidazole-chalcone derivatives were assessed for synergistic effects using the checkerboard method. Four imidazole-chalcone derivatives to which probiotic bacteria were tolerant exhibited antibacterial and antifungal activity against the human pathogens tested. To our knowledge, this study is the first to reveal the fractional inhibitory concentration (FIC) of combinations of imidazole-chalcone derivatives. Indeed, the minimum inhibitory concentrations (MIC) for morpholinyl- (ZDO-3f) and 4-ethylpiperazinyl- (ZDO-3 m) imidazole-chalcones were notably low when tested against E. coli and B. subtilis, with values of 31.25 μg/mL and 125 μg/mL, respectively. The combination of morpholinyl- and 4-ethylpiperazinyl derivatives demonstrated an indifferent effect against E. coli, but an additive effect was observed for B. subtilis. Additionally, it was observed that imidazole-chalcone derivatives did not exhibit any inhibitory effects on probiotic organisms like Lactobacillus fermentum (CECT-5716), Lactobacillus rhamnosus (GG), and Lactobacillus casei (RSSK-591). This study demonstrates that imidazole-chalcone derivatives that are well tolerated by probiotics can potentially exert a synergistic effect against gastrointestinal system pathogens.

In vitro antimicrobial, antibiofilm photodynamic activity, and molecular dynamic simulations of tetra-cationic porphyrinmembrane interactions against foodborne microorganisms.

This manuscript presents a new report on the in vitro antimicrobial photo-inactivation of foodborne microorganisms (Salmonella spp. and Listeria monocytogenes) using tetra-cationic porphyrins. Isomeric tetra-cationic porphyrins (3MeTPyP, 4MeTPyP, 3PtTPyP, and 4PtTPyP) were tested, and antimicrobial activity assays were performed at specific photosensitizer concentrations under dark and white-light LED irradiation conditions. Among the tested bacterial strains, 4MeTPyP exhibited the highest efficiency, inhibiting bacterial growth within just 60min at low concentrations (17.5μM). The minimal inhibitory concentration of 4MeTPyP increased when reactive oxygen species scavengers were present, indicating the significant involvement of singlet oxygen species in the photooxidation mechanism. Furthermore, the checkerboard assay testing the association of 4MeTPyP showed an indifferent effect. Atomic force microscopy analyses and dynamic simulations were conducted to enhance our understanding of the interaction between this porphyrin and the strain's membrane.

Investigation of the Antibacterial Synergistic Activity of Fosfomycin-Teicoplanin Combination in Methicillin-Resistant Staphylococcus aureus Strains Isolated from Various Clinical Sample

The aim of this study was to investigate the detection of teicoplanin and fosfomycin antibiotic susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) strains by different methods and to evaluate the antibacterial synergistic effect of teicoplanin-fosfomycin combination by using checkerboard assay and time kill curve assay. Forty-five MRSA strains isolated from clinical samples in routine medical microbiology laboratory of Göztepe Prof. Dr. Süleyman Yalçın City Hospital were included in the study. In the first stage of the combination study, minimum inhibitory concentrations (MIC) were investigated by broth microdilution for teicoplanin and by both broth microdilution and agar dilution methods for fosfomycin. The combination of teicoplanin and fosfomycin was tested by the checkerboard method in 45 MRSA strains and combination effect was determined according to fractional inhibitory concentration index (ΣFIC) calculation. The synergistic effect and bactericidal activity of antibiotic combination were studied against a randomly selected strain from the strains used in the study by using time-kill method for 24 hours. As a result of teicoplanin and fosfomycin antibiotic susceptibility studies, all isolates were found to be susceptible to both antibiotics according to the susceptibility breakpoints determined by the European Committee on Antimicrobial Susceptibility Testing (EUCAST). A synergistic effect was found in 22 (49%), additive effect in 22 (49%) and indifferent effect in one (2%) of the 45 strains studied with the checkerboard method. The mean ΣFIC of 45 isolates was found to be 0.5. In the combination study of the antibiotics of the isolate that was studied with time-kill method, synergism was detected for 1/8 MIC concentrations at 12th hour and 24th hour and synergism at 1/4 MIC concentration at sixth hour, 12th hour and 24th hour. In the combination study of 1/4 MIC concentrations of antibiotics, bactericidal effect was detected at sixth hour and this effect was observed to disappear at 12th and 24th hours. High rate of synergistic antibacterial effect of teicoplanin-fosfomycin combination on MRSA isolates was demonstrated as a result of in vitro tests. Such studies conducted on antibiotic-resistant bacterial infections will provide clinicians different treatment options and will contribute to increasing survival. As a result of this study, provided that it is supported by future clinical studies, it can be stated that the teicoplanin-fosfomycin combination may be an effective treatment option in community and hospital-acquired infections caused by MRSA.

School Dropout Causes in Turkish Education System (2009-2022): A Pareto Analysis by Grade Level

The aim of this research is to examine the reasons for school dropout occurring at varying education levels in the Turkish education system (TES). In this direction, research on school dropout pertaining to TES has been targeted. The systematic data analysis method was used in the research. 47 studies suitable for the purposes of the study were analyzed through content analysis. A total of 290 coding processes were carried out. According to the results of the research, the family factor comes to the fore in the causes of school dropout in primary education in TES. The inadequacy of families’ financial situation and low interest in education are effective. At the high school level, students' academic failure, absenteeism, peer pressure, and indifference of families appear as the causes of school dropouts. In higher education, difficulties learners experience in adapting to novel social environments, academic failure, financial problems and the thought of being a misfit for the selected department seem to be amongst the causes of school dropout. In the other group, the reasons of dropping out are determined as academic failure, financial difficulties, early marriages, dislike of school, indifference of family, negative effects of friend groups and indifference towards school.

Phytochemicals and antimicrobial properties of Thai edible plant extracts and their prebiotic-like effects

In this study, the phytochemicals and antimicrobial activities of ethanolic extracts of Thai edible plants, green tea, red cotton tree flower, fingerroot and ginger were evaluated. The plant extracts were taken for evaluation of antimicrobial activities against Cutibacterium acnes DMST 14916, Staphylococcus epidermidis TISTR 518, and Staphylococcus aureus TISTR 746. The minimum inhibitory concentrations (MICs) of green tea, fingerroot, and ginger extracts against C. acnes DMST 14916 were 3.92, 0.49, and 7.85 mg cm-3, respectively and the minimum bacteriostatic concentrations (MBCs) were 3.92, 0.49, and 7.85 mg cm-3, respectively. The MICs and MBCs of fingerroot extract against S. epidermidis TISTR 518 were 0.12 and 0.49 mg cm-3, respectively, while those against S. aureus TISTR 746 were 0.12 and 0.98 mg cm-3, respectively. Red cotton tree flower extract showed no antimicrobial activity against the acne-causing bacteria. By scanning electron microscopy (SEM) evaluation, the bacterial cells treated with the plant extracts revealed visible shrinkages compared to the smooth cell surfaces of the controls. The phytochemicals in the plant extracts were analysed by liquid chromatography with tandem mass spectrometry (LC-MS/MS). Well-known antimicrobial compounds like azelaic acid, embelin and kaempferol 3-rutinoside-4′-glucoside were identified in all extracts. The cytotoxic effects of the plant extracts on human cell lines were further investigated. The green tea extract was slightly toxic to HaCaT cells found at the initial concentration of 62.5 mg cm-3, but not toxic to MRC-5 cells. The fingerroot and ginger extracts had no cytotoxicity on HaCaT cells, but promoted the MRC-5 cell proliferation. The combination effects of the plant extracts were prebiotic-like and indifferent effects. Regarding all results, the ethanolic extracts of green tea, fingerroot, and ginger could be used individually as natural anti-acne ingredients capable of further product development to improve human skin health.

Evaluation of the antibacterial, modulatory and anti-adherent properties of oregano (Origanum vulgare) essential oil against food pathogenic bacteria

There are over 250 types of foodborne diseases, the majority of which are infections caused by bacteria. Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus saprophyticus are considered contaminants of meat products. The use of natural products as antimicrobials to combat these diseases can be an effective and economical approach. This study proposes to assess the antibacterial, modulatory, and anti-adherent activity of the essential oil of Origanum vulgare against strains of Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus saprophyticus isolated from meat products. The assay was conducted in duplicate. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were determined using the broth microdilution technique. MIC represents the lowest concentration of the product capable of inhibiting the growth of the bacterial strain, whereas MBC represents the lowest concentration capable of inhibiting total growth. The study of association of the product with antimicrobials was undertaken by disk diffusion using ampicillin, gentamicin, ceftazidime, and ciprofloxacin, resulting in synergistic, antagonistic, or indifferent effects. Anti-adherent activity was determined in the presence of sucrose, as the lowest concentration of the agent in contact with sucrose that prevented adherence to the glass tube. Oregano oil exhibited strong inhibitory and bactericidal activity against Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus saprophyticus, with MIC values ranging from 32 to 512 μg mL-1 and MBC values ranging from 128 to 512 μg mL-1. Origanum vulgare oil showed varied interactions when associated with antimicrobials, with modulations for synergism (37.5%), indifference (50%), and antagonism (12.5%). Regarding anti-adherent activity, the test product effectively inhibited the adherence of P. aeruginosa bacterial strains in the presence of sucrose (1:8) but had no effect against K. pneumoniae or S. saprophyticus. Therefore, oregano oil proves to be an antibacterial and modulating agent against different bacteria isolated from meat products. Additionally, it displays anti-adherent properties against P. aeruginosa, making it a natural product that could serve as an interesting alternative in efforts to combat foodborne diseases.

KOJİK ASİT İLE LAVANDULA ANGUSTIFOLIA L. UÇUCU YAĞININ ANTİMİKROBİYAL KOMBİNASYONU

Objective: Lavandula angustifolia L. (Lavender) is one of the most plants essential oils used in the cosmetic, food and biological activities. Kojic acid has been used in cosmetics for its whitening effect and pharmaceutical activity. The aim of this study to determine the composition of the Pharmacopoeia quality L. angustifolia essential oil (EO). Moreover, antimicrobial activities against skin pathogens and synergistic antibacterial activity were also examined of EO and kojic acid. Material and Method: In this work, chemical composition of the EO was defined. Linalyl acetate (43.3%) and linalool (38.6%) were determined as the major components by GC-MS and GC-FID, simultaneously. The antimicrobial activity was evaluated against Candida albicans, C. glabrata, Staphylococcus aureus and Salmonella typhimurium. Result and Discussion: EO and kojic acid showed weak antimicrobial effects. MIC values were determined as the EO 10 mg/ml and kojic acid 1.25 mg/ml against S. typhimurium. To assess the synergistic activity was evaluated by the checkerboard microdilution assay, EO was combined with kojic acid against S. typhimurium. Among the tested skin pathogen microorganisms, S. typhimurium was more sensitive to kojic acid. Therefore, synergic activity was investigated against S. typhimurium and found indifferent effect.

The Impact of Foreign Direct Investment on Poverty Reduction: Evidence from Bangladesh

This study aims to identify the contribution of foreign direct investment on poverty reduction in Bangladesh with a data period of 32 years starting from FY 1991 to FY 2022 with annual observations in real term. Besides foreign direct investment, gross domestic product, government expenditure on education, employment, and trade openness are used as control variables. Per capita consumption is used as a proxy for poverty reduction. The study goes for Johansen Co-integration test and then Vector Error Correction Model rather than Ordinary Least Squares Regression to avoid any spurious result as indicated by Augmented Dickey-Fuller test. This study finds that FDI has significantly negative relationship while Employment has almost indifferent effect on poverty reduction in the long run. However, other control variables, i.e., GDP, Govt. Expenditure on education and Trade openness have long run positive relationship in this regard. The short run causality of FDI toward poverty reduction is also insignificant in Bangladesh.

Fungicidal and antibiofilm activities of 2-Bromo-N-Phenylacetamide Against Fluconazole-Resistant Candida spp.: a promising antifungal agent

Purpose: Amides are proven to possess antimicrobial properties against both fungi and bacteria. The synthetic amide 2-bromo-N-phenylacetamide exhibits antifungal activity according to scientific literature, however, data remains scarce. Given the clinical and epidemiological importance as well as the increasing antifungal resistance in Candida spp., here we aimed to better explore the antifungal potential of 2-bromo-N-phenylacetamide against fluconazole-resistant Candida albicans, Candida glabrata, Candida parapsilosis and for the first time, against Candida tropicalis as well. Methods: Minimum Inhibitory and Minimum Fungicidal Concentrations (MIC/MFC) were established by a Broth Microdilution Technique. Mode of action was explored by Ergosterol and Sorbitol assays. For investigating the combined effect between 2-bromo-N-phenylacetamide and the standard antifungals Amphotericin B and Fluconazole a Checkerboard Technique was performed. Finally, the antibiofilm properties of 2-bromo-N-phenylacetamide were assessed by a Crystal Violet Staining Assay. Results: 2-bromo-N-phenylacetamide exhibited a fungicidal effect, MIC of 32 µg.mL-1 (87.5% of the strains) and MFC of 64 µg.mL-1 (81.25% of the strains). It also demonstrated an activity against Candida albicans mature biofilms as effective as that for Amphotericin B at all tested concentrations. When associated with Fluconazole and Amphotericin B it exerted indifferent effects. Mode of action remained unclear. Conclusion: The synthetic amide 2-bromo-N-phenylacetamide possesses a strong antifungal activity against Candida albicans, Candida tropicalis, Candida glabrata and Candida parapsilosis and an antibiofilm property against Candida albicans as effective as that exhibited for Amphotericin B.

Assessing the Potential of Gallic Acid and Methyl Gallate to Enhance the Efficacy of β-Lactam Antibiotics against Methicillin-Resistant Staphylococcus aureus by Targeting β-Lactamase: In Silico and In Vitro Studies.

Methicillin-resistant Staphylococcus aureus (MRSA), a global health concern, has prompted research into antibiotic adjuvants as a potential solution. Although our group previously reported the enhancing effects of gallic acid (GA) and methyl gallate (MG) on penicillin G activity against MRSA, the synergistic potential with other β-lactam antibiotics and the underlying mechanism have not been fully explored. Therefore, this study primarily aimed to investigate the antibacterial synergism with β-lactam antibiotics through disc diffusion, checkerboard, and time-kill assays. The β-lactamase inhibition was also examined through both molecular modeling and in vitro experiments. Additionally, bacterial morphology changes were studied using a scanning electron microscopy (SEM). The results revealed that both GA and MG exhibited anti-MRSA activity and showed indifferent effects when combined with β-lactam antibiotics against methicillin susceptible S. aureus (MSSA). Interestingly, MG demonstrated synergism with only the β-lactamase-unstable antibiotics against MRSA with the lowest fractional inhibitory concentration (FIC) indexes of ≤3.75. However, GA and MG exhibited weak β-lactamase inhibition. Furthermore, GA, MG, and the combination with ampicillin induced the morphological changes in MRSA, suggesting a possible mechanism affecting the cell membrane. These findings suggest that MG could potentially serve as an adjunct to β-lactam antibiotics to combat MRSA infections.

Derivative of 7-hydroxycoumarin has antifungal potential against Candida species and low cytotoxicity against human cells: In silico studies and biological evaluation

This study investigates the antifungal and cytotoxic properties of 7-(pentyloxy)-2H-chromen-2-one. Through molecular docking and dynamics simulations, we explored the compound's interactions with fungal cell protein targets. Notably, it exhibited strong affinities for 1,3β-glucan synthase, squalene epoxidase, δ-14-sterol reductase, 14-α-demethylase, and thymidylate synthase, with binding energies ranging from -100.39 to -73.15 kcal/mol. Molecular dynamics simulations confirmed its stable binding at active targets. The MIC and MFC values ranged from 67.16 μM (15.6 μg/mL) to 537.28 μM (125.0 μg/mL). The compound displayed promising antifungal effects, inhibiting fungal growth for at least 24 hours. Fungal plasma membrane function alteration likely contributed to these antifungal mechanisms. Additionally, the combination of the compound with nystatin, fluconazole, and caspofungin showed indifferent effects on antifungal activity. Cytotoxicity assessment in human keratinocyte cells (HaCaT) revealed an IC50 of 100 μM, which was approximately 1.5 times higher than the MIC for C. krusei. Thus, the compound exhibited strongly in silico and in vitro antifungal activity with low cytotoxicity in HaCaT cells. These findings support its potential as a candidate for further development as an antifungal compound.

Efficacy of oritavancin and nisin alone and their combination against vancomycin resistant enterococci strains in hospitalized patients in Turkiye

PurposeVancomycin-Resistant Enterococci (VREs) have emerged and become a problem that threatens the health of hospitalized patients. VRE can cause different serious infections of the urinary tract, the bloodstream, wound and other body sites. VREs are resistant to multiple antibiotics and treatment options are very limited. We aimed to investigate the efficacy of oritavancin and nisin alone and their combination against VRE strains. MethodsVRE isolates from rectal swabs of hospitalized patients were identified by conventional and commercial methods. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of oritavancin and nisin against VRE strains were determined. The synergistic effect of both agent combinations was examined by the Checkerboard test. ResultsAll VRE strains were identifined as Enterococcus faecium. The MIC value of oritavancin was found in the range of 0.015–0.24 ​μg/mL; in which 48 strains were susceptible (≤0.12 ​μg/mL) and two strains were resistant (>0.12 ​μg/mL). The MBC of oritavancin was determined in the range of 0.06–3.84 ​μg/mL. The MIC of nisin was found in the range of 12.5–100 ​μg/mL; in which 32 strains were susceptible (≤50 ​μg/mL) and 18 strains were resistant (>50 ​μg/mL). MBC of nisin was determined in the range of 25–800 ​μg/mL. Two oritavancin resistant strains were displayed indifference effect, whereas from 18 nisin resistant strains, 11 showed indifference, and seven displayed synergistic effect. Thirty-eight out of 48 strains which were sensitive to oritavancin showed indifference and 10 revealed synergistic effect, whereas 29 of 32 strains which were sensitive to nisin showed indifference and three had synergistic effect. ConclusionsA synergistic combination of oritavansin and nisin was detected in 20 strains (40%), Our study is the first study in Turkiye.

Synergistic Combination of Antimicrobial Peptides and Cationic Polyitaconates in Multifunctional PLA Fibers.

Combining different antimicrobial agents has emerged as a promising strategy to enhance efficacy and address resistance evolution. In this study, we investigated the synergistic antimicrobial effect of a cationic biobased polymer and the antimicrobial peptide (AMP) temporin L, with the goal of developing multifunctional electrospun fibers for potential biomedical applications, particularly in wound dressing. A clickable polymer with pendent alkyne groups was synthesized by using a biobased itaconic acid building block. Subsequently, the polymer was functionalized through click chemistry with thiazolium groups derived from vitamin B1 (PTTIQ), as well as a combination of thiazolium and AMP temporin L, resulting in a conjugate polymer-peptide (PTTIQ-AMP). The individual and combined effects of the cationic PTTIQ, Temporin L, and PTTIQ-AMP were evaluated against Gram-positive and Gram-negative bacteria as well as Candida species. The results demonstrated that most combinations exhibited an indifferent effect, whereas the covalently conjugated PTTIQ-AMP displayed an antagonistic effect, potentially attributed to the aggregation process. Both antimicrobial compounds, PTTIQ and temporin L, were incorporated into poly(lactic acid) electrospun fibers using the supercritical solvent impregnation method. This approach yielded fibers with improved antibacterial performance, as a result of the potent activity exerted by the AMP and the nonleaching nature of the cationic polymer, thereby enhancing long-term effectiveness.

The Direction of the Antibacterial Effect of Rutin Hydrate and Amikacin.

The aim of the presented study was to examine the in vitro antimicrobial activity of rutin hydrate (RH) alone and in combination with amikacin against 12 reference strains of Gram-positive and Gram-negative bacteria. The antibacterial activity assay was evaluated in the concentration range of 2-2048 µg/mL. A serial microdilution method was used to determine the minimal inhibitory concentration (MIC) of the examined compound against reference strains. RH showed varying potential against the tested strains with MICs ranging from 128 to 1024 µg/mL. In order to examine the combinatory profile of RH and amikacin, the fractional inhibitory concentrations (FICs) were determined. The RH-amikacin combination was more active against Gram-negative bacteria where four synergism and two additive interactions were noted. For four out of six Gram-positive isolates, an indifferent effect of RH and amikacin was demonstrated, and for two strains, the tested combination had an additive effect. The results of this study showed that RH possesses antimicrobial potential in vitro towards the tested reference isolates. Moreover, it shows a promising combined effect with amikacin against Gram-negative bacteria.

Potentiation of Antibacterial Activity of Ciprofloxacin by Essential Oil of Cymbopogon citratus against Fluoroquinolone-resistant Staphylococcus aureus and Escherichia coli

Background: Essential oil (EO) of Cymbopogon citratus has been demonstrated to have antibacterial activities against both Gram negative and Gram positive bacteria. The study was, therefore, conducted to evaluate the effects of combined use of C. citratus and ciprofloxacin against fluoroquinolone-resistant Staphylococcus aureus (FQRSA) and Escherichia coli (FQREC).
 Methods: The antibacterial activity of the essential oil was evaluated by agar dilution method while the combination studies were done using Checker-board agar dilution technique.
 Results: The mean MIC values of EO against the FQRSA and FQREC were 0.043 + 0.01 mg/ml and 0.049 mg/ml respectively. When ciprofloxacin was combined with EO of lemongrass, 53.9, 28.3, 17.8 and 0.0 % of the FQRSA isolates showed indifference, additive, synergistic and antagonistic effects respectively. Similarly, when ciprofloxacin was combined with EO of lemongrass at different ratios, 44, 35.5, 20.6 and 0.0 % of the FQREC isolates showed combined effects of additivity, synergism, indifference and antagonism respectively.
 Conclusions: The results revealed the invitro antibacterial potency of Cymbopogon citratus oil against fluoroquinolone resistant S. aureus and E. coli. More importantly, the study has proved that the combined use of ciprofloxacin and essential oil of lemongrass has increased the sensitivity of both FQRSA and FQREC bacteria.