Minimum Inhibitory Concentration Values Research Articles

SYNERGISTIC EFFECT OF HERBAL TEA SAMPLES WITH CIPROFLOXACIN AGAINST MRSA AND THEIR ANTIOXIDANT ACTIVITIES

OBJECTIVE: Sambucus nigra L. (elderberry), Salvia sclarea L. (clary sage), Rosmarinus officinalis L. (rosemary), and Coriandrum sativum L. (coriander) are all consumed as flavoring agents for food and are well-known in traditional medicine for the treating various diseases worldwide. These herbs are also commonly used for microbial infections, especially to relieve cough, fever, and cold symptoms. This study aims to screen and compare the content of total phenols and antioxidant activity potential of three different extracts from each commercial sample of S. nigra, S. sclarea, R. officinalis and C. sativum from Türkiye. We also investigated the (Minimum Inhibitory Concentration (MIC) values against Staphylococcus aureus ATCC 29213 (methicillin-susceptible, MSSA) and Staphylococcus aureus ATCC 43300 (methicillin-resistant, MRSA) and the synergistic activity with an antibiotic, ciprofloxacin, by checkerboard assay. MATERIAL AND METHODS: The fruits of S. nigra and C. sativum, the aerial parts of S. sclarea, and the leaves of R. officinalis were purchased from a trading company that marketed them as herbal tea in Türkiye. This study investigated the total phenolic content and antioxidant potential of extracts from commercial samples. We also determined the synergistic effect of herbal tea samples with ciprofloxacin against methicillin-resistant Staphylococcus aureus (MRSA). RESULTS: R. officinalis (rosemary) and Salvia sclarea (clary sage) extracts showed high phenolic content and antioxidant activity, whereas it was determined that C.sativum (coriander) and S. nigra (elderberry) extracts exhibited lower antioxidant activity and low phenolic compounds. Moreover, ciprofloxacin in combination with the ethanolic extract of S. sclarea showed additive antibacterial activity against S. aureus ATCC 43300. CONCLUSIONS: We conclude that herbal tea prepared from commercial R. officinalis (rosemary) and S.sclarea (clary sage) samples can support the antioxidant activity with high phenolic content and that ciprofloxacin combined with the ethanolic extract of clary sage showed additive antibacterial activity against methicillin-resistant S. aureus ATCC 43300. Further studies are needed to understand the mechanism of additive action in detail.

Comparison of available methods to evaluate cefiderocol susceptibility in Acinetobacter spp

Recently, considerable uncertainty has arisen concerning the appropriate susceptibility testing for cefiderocol in gram-negative bacilli, particularly in the context of its application to Acinetobacter spp. The optimal method for assessing the susceptibility levels of Acinetobacter spp. to cefiderocol remains a subject of debate due to substantial disparities observed in the values obtained through various testing procedures. This study employed four minimum inhibitory concentration (MIC) methodologies and the disk diffusion to assess the susceptibility of twenty-seven carbapenem resistant (CR)-Acinetobacter strains to cefiderocol. The results from our study reveal significant variations in the minimum inhibitory concentration (MIC) values obtained with the different methods and in the level of agreement in interpretation categories between the different MIC methods and the disk diffusion test. Among the MIC methods, there was relatively more consistency in reporting the interpretation categories. For European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints, the categorical agreement (CA) for MIC methods ranged between 66.7 and 81.5%. On the other hand, the essential agreement (EA) values were as low as 18.5–29.6%. The CA between MIC methods and disk diffusion was 81.5%. These results emphasize the need for a reliable, accurate, and clinically validated methodology to effectively assess the susceptibility of Acinetobacter spp. to cefiderocol. The wide variability observed in our study highlights the importance of standardizing the susceptibility testing process for cefiderocol to ensure consistent and reliable results for clinical decision-making.

Pioneering Topical Ointment Intervention for Unprecedented Antimicrobial and Diabetic Wound Management with Phenylpropanoids and Nano-Silver.

Addressing the intertwined challenges of antimicrobial resistance and impaired wound healing in diabetic patients, an oil/water emulsion-based nano-ointment integrating phenylpropanoids-Eugenol and Cinnamaldehyde-with positively-charged silver nanoparticles was synthesized. The process began with the synthesis and characterization of nano-silver, aimed at ensuring the effectiveness and safety of the nanoparticles in biological applications. Subsequent experiments determined the minimum inhibitory concentration (MIC) against pathogens such as Streptococcus aureus, Pseudomonas aeruginosa and Candida albicans. These MIC values of all three active leads guided the strategic formulation of an ointment base, which effectively integrated the bioactive components. Evaluations of this nano-ointment revealed enhanced antimicrobial activity against both clinical and reference bacterial strains and it maintained stability after freeze-thaw cycles. Furthermore, the ointment demonstrated superior in-vitro diabetic wound healing capabilities and significantly promoted angiogenesis, as shown by enhanced blood vessel formation in the Chorioallantoic Membrane assay. These findings underscore the formulation's therapeutic potential, marking a significant advance in the use of nanotechnology for topical wound care.

Pfaffia paniculata Extract, a Potential Antimicrobial Agent against Candida spp., Pseudomonas aeruginosa, and Streptococcus mutans Biofilms.

The World Health Organization (WHO) has prioritized developing new drugs against specific bacteria and fungi, such as Enterobacteriaceae and Candida spp. While Pfaffia paniculata is commonly called the "cure-everything", its scientifically proven benefits are limited to anti-inflammatory and antioxidant actions. Therefore, this study aims to determine the spectrum of antimicrobial activity of Pfaffia paniculata and assess its cytotoxicity. Thus, broth microdilution test was conducted according to the CLSI M7-A9 and M27-A3 reference methods. After screening, microbial species with minimum inhibitory concentration (MIC) values were selected for biofilm tests. These tests evaluated biomass using the crystal violet (CV) test, metabolic activity using the MTT assay, and structural analysis via Scanning Electron Microscopy (SEM). Cytotoxicity was evaluated in human gingival fibroblasts (FMM-1). There were reductions of 29.4 and 42.7% in CV and MTT assays for Candida spp. biofilm. S. mutans and P. aeruginosa biofilms showed a decrease of 15.7 and 28.6%, respectively. Cell viability tests indicated 55.1, 56.9, and 65.5% of viability after contact with 1.93, 0.96, and 0.48 mg/mL of the extract, respectively. The P. paniculata extract showed antimicrobial action, displayed MIC values, and antibiofilm action on P. aeruginosa, S. mutans, and C. albicans. The cytotoxicity on the FMM-1 cell line was dose-dependent. Therefore, P. paniculata extract holds significant potential for developing new drugs.

Marcytoglobosins A and B, Cytochalasans From a Marine Sponge Associated Chaetomium globosum 162105 Fungus.

Two new cytochalasans, marcytoglobosins A (1) and B (2) were isolated from the marine sponge associated fungus Chaetomium globosum 162105, along with six known compounds (3-8). The complete structures of two new compounds were determined based on 1D/2D NMR and HR-MS spectroscopic analyses coupled with ECD calculations. All eight isolates were evaluated for their antibacterial activity. Among them, compounds 3-8 displayed antibacterial effects against Staphylococcus epidermidis, Bacillus thuringiensis, Pseudomonas syringae pv. Actinidiae, Vibrio alginolyticus, and Edwardsiella piscicida with minimum inhibitory concentration (MIC) values ranging from 10 to 25 μg/mL.

Vitamins Can Increase Antibiotic Effects Against Multidrug-Resistant Pseudomonas aeruginosa and Acinetobacter baumannii in an In Vitro Infection Model.

The study delves into the antimicrobial properties of vitamins P, K, and E against A. baumannii and P. aeruginosa, employing the minimum inhibitory concentration method and scrutinizing biofilm formation within the A549 cell culture. The combined application of vitamins and antibiotics exhibited a statistically significant effect on both the minimal inhibitory concentration values and biofilm formation (P < .05). Within the realm of fat-soluble vitamins, vitamins K and E, when integrated with antibiotics, revealed varying degrees of influence, with vitamin K displaying the most substantial fractional inhibitory concentration value. Vitamin E, on the other hand, demonstrated a comparatively weaker fractional inhibitory concentration than the other constituents. Nevertheless, it exhibited robust optical density and a pronounced capacity to inhibit biofilm formation. Moreover, among the vitamin groups, it is evident that vitamin E surpasses the efficacy of others (antibacterials affecting K < P <E). The collective application of all vitamins manifested the most potent fractional inhibitory concentration. The synergistic effects of vitamins with antibiotics, as evidenced in this study, may offer a promising alternative for treating multidrug-resistant A. baumannii and P. aeruginosa, subject to further investigation through molecular studies.

Green Synthesis of CuO/ZnO Nanocomposites using Ficus Drupacea: In‐Vitro Antibacterial and Cytotoxicity Analysis

AbstractWith the increasing demand for environmentally friendly and effective biomedical solutions, the synthesis of nanoparticles with enhanced properties has become imperative. This study addresses this demand by employing a green method that utilizes Ficus Drupacea fruit extract to produce ZnO/CuO nanostructures, offering versatile biomedical applications. While several reports exist on the synthesis of nanostructures using plant extracts, this is the primary report on the utilization of Ficus Drupacea fruit extract for creating ZnO/CuO nanostructures. A series of five ZnO/CuO nanostructures (ZC0, ZC25, ZC50, ZC75, and ZC100) were synthesized by varying the proportion of CuO and ZnO. Through comprehensive characterization techniques including XRD (X‐Ray Diffraction), HR‐TEM (High‐Resolution Transmission Electron Microscopy), and UV‐Vis spectroscopy, the successful synthesis and tunable properties of the nanostructures were confirmed, with average crystal sizes ranging from 14.32 nm to 38.61 nm. The study unveils the significant cytotoxicity of the synthesized nanostructures against MCF‐7 breast cancer cells, with ZC25 demonstrating the highest activity and an LC50 (Lethal Concentration 50) value below 50 μg/mL. Antimicrobial assays underscore the potent activity of ZC100 against Streptococcus mutans and Acinetobacter baumannii, with MIC (Minimum Inhibitory Concentration) values below 1.5 mg/mL. These findings emphasize the potential of these nanostructures for advanced biomedical applications.

Discovery of new Schiff bases of the disalicylic acid scaffold as DNA gyrase and topoisomerase IV inhibitors endowed with antibacterial properties.

DNA gyrase and topoisomerase IV show great potential as targets for antibacterial medicines. In recent decades, various categories of small molecule inhibitors have been identified; however, none have been effective in the market. For the first time, we developed a series of disalicylic acid methylene/Schiff bases hybrids (5a-k) to act as antibacterial agents targeting DNA gyrase and topoisomerase IV. The findings indicated that the new targets 5f-k exhibited significant antibacterial activity against Gram-positive and Gram-negative bacteria, with efficacy ranging from 75% to 115% of the standard ciprofloxacin levels. Compound 5h demonstrated the greatest efficacy compared to the other compounds tested, with minimum inhibitory concentration (MIC) values of 0.030, 0.065, and 0.060μg/mL against S. aureus, E. coli, and P. aeruginosa. 5h had a MIC value of 0.050μg/mL against B. subtilis, which is five times less potent than ciprofloxacin. The inhibitory efficacy of the most potent antibacterial derivatives 5f, 5h, 5i, and 5k against E. coli DNA gyrase was assessed. The tested compounds demonstrated inhibitory effects on E. coli DNA gyrase, with IC50 values ranging from 92 to 112nM. These results indicate that 5f, 5h, 5i, and 5k are more effective than the reference novobiocin, which had an IC50 value of 170nM. Compounds 5f, 5h, 5i, and 5k were subjected to additional assessment against E. coli topoisomerase IV. Compounds 5h and 5i, which have the highest efficacy in inhibiting E. coli gyrase, also demonstrated promising effects on topoisomerase IV. Compounds 5h and 5i exhibit IC50 values of 3.50µM and 5.80 µM, respectively. These results are much lower and more potent than novobiocin's IC50 value of 11µM. Docking studies demonstrate the potential of compound 5h as an effective dual inhibitor against E. coli DNA gyrase and topoisomerase IV, with ADMET analysis indicating promising pharmacokinetic profiles for antibacterial drug development.

Application of single-cell Raman-deuterium isotope probing to reveal the resistance of marine ammonia-oxidizing archaea SCM1 against common antibiotics

Antimicrobial resistance (AMR) in oceans poses a significant threat to human health through the seafood supply chain. Ammonia-oxidizing archaea (AOA) are important marine microorganisms and play a key role in the biogeochemical nitrogen cycle around the world. However, the AMR of marine AOA to aquicultural antibiotics is poorly explored. Here, Raman-deuterium isotope probing (Raman-DIP), a single-cell tool, was developed to reveal the AMR of a typical marine species of AOA, Nitrosopumilus maritimus (designated SCM1), against six antibiotics, including erythromycin, tetracycline, novobiocin, neomycin, bacitracin, and vancomycin. The D2O concentration (30% v/v) and culture period (9 days) were optimized for the precise detection of metabolic activity in SCM1 cells through Raman-DIP. The relative metabolic activity of SCM1 upon exposure to antibiotics was semi-quantitatively calculated based on single-cell Raman spectra. SCM1 exhibited high resistance to erythromycin, tetracycline, novobiocin, neomycin, and vancomycin, with minimum inhibitory concentration (MIC) values between 100 and 400 mg/L, while SCM1 is very sensitive to bacitracin (MIC: 0.8 mg/L). Notably, SCM1 cells were completely inactive under the metabolic activity minimum inhibitory concentration conditions (MA-MIC: 1.6–800 mg/L) for the six antibiotics. Further genomic analysis revealed the antibiotic resistance genes (ARGs) of SCM1, including 14 types categorized into 33 subtypes. This work increases our knowledge of the AMR of marine AOA by linking the resistant phenome to the genome, contributing to the risk assessment of AMR in the underexplored ocean environment. As antibiotic resistance in marine microorganisms is significantly affected by the concentration of antibiotics in coastal environments, we encourage more studies concentrating on both the phenotypic and genotypic antibiotic resistance of marine archaea. This may facilitate a comprehensive evaluation of the capacity of marine microorganisms to spread AMR and the implementation of suitable control measures to protect environmental safety and human health.

Dual fluorescence response of calix[4]arene-1,8-naphthalimide derivatives towards Hg(II) /Cr(VI) and their antimicrobial studies of transparent biofilms with hyaluronic acid

In this study, 4-sulfo-1,8-naphthalimide calixarene of derivatives were prepared (3 and 4) then transparent biofilms of the Ag salts of these compounds were formed in the presence of hyaluronic acid (HA), and antimicrobial properties were investigated. In chemosensor studies, the sensing ability behavior of 3 and 4 towards some cations and anions was investigated by fluorescence spectroscopy. It was observed that the prepared chemosensors show selectivity towards Hg(II) and Cr(VI). Ligand-ion interaction occurs according to the photo-induced electron transfer (PET) mechanism. The stoichiometric ratio was calculated by using Stern-Volmer plot method and binding constant Ksv values were found as 5.2 × 107 M−1 and 5.5 × 107 M−1 for 3-Hg(II) and 4-Hg(II) complexes, respectively and 4.0 × 107 M−1 and 4.3 × 107 M−1 for 3-Cr(VI) and 4-Cr(VI) complexes. The detection limits of the complexes of 3-Hg(II) and 4-Hg(II) are 6.35 × 10−12and 6.81 × 10−12, while those of 3-Cr(VI) and 4-Cr(VI) are 1.41 × 10- 11and 8.37 × 10−12, respectively. As a result of the antimicrobial test performed with these compounds, it was observed that the most effective material was HA-3Ag, which showed a significant antibacterial effect against Sarcina lutea (S. lutea) at a minimum inhibitory concentration (MIC) value of 0.097 mg/mL.

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 (&lt;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.

Mobile Colistin-Resistant Genes mcr-1, mcr-2, and mcr-3 Identified in Diarrheal Pathogens among Infants, Children, and Adults in Bangladesh: Implications for the Future.

Colistin is a last-resort antimicrobial for treating multidrug-resistant Gram-negative bacteria. Phenotypic colistin resistance is highly associated with plasmid-mediated mobile colistin resistance (mcr) genes. mcr-bearing Enterobacteriaceae have been detected in many countries, with the emergence of colistin-resistant pathogens a global concern. This study assessed the distribution of mcr-1, mcr-2, mcr-3, mcr-4, and mcr-5 genes with phenotypic colistin resistance in isolates from diarrheal infants and children in Bangladesh. Bacteria were identified using the API-20E biochemical panel and 16s rDNA gene sequencing. Polymerase chain reactions detected mcr gene variants in the isolates. Their susceptibilities to colistin were determined by agar dilution and E-test by minimal inhibitory concentration (MIC) measurements. Over 31.6% (71/225) of isolates showed colistin resistance according to agar dilution assessment (MIC > 2 μg/mL). Overall, 15.5% of isolates carried mcr genes (7, mcr-1; 17, mcr-2; 13, and mcr-3, with co-occurrence occurring in two isolates). Clinical breakout MIC values (≥4 μg/mL) were associated with 91.3% of mcr-positive isolates. The mcr-positive pathogens included twenty Escherichia spp., five Shigella flexneri, five Citrobacter spp., two Klebsiella pneumoniae, and three Pseudomonas parafulva. The mcr-genes appeared to be significantly associated with phenotypic colistin resistance phenomena (p = 0.000), with 100% colistin-resistant isolates showing MDR phenomena. The age and sex of patients showed no significant association with detected mcr variants. Overall, mcr-associated colistin-resistant bacteria have emerged in Bangladesh, which warrants further research to determine their spread and instigate activities to reduce resistance.

Synergistic effect of SrTiO3/CuFe2O4/MIL-101(Co) as a MOF composite under Gamma-rays for antimicrobial potential versus bacteria and pathogenic fungi

The primary emphasis of this study was on the innovative and scientifically valuable hydrothermal synthesis of MIL-101(Co) as a metal-organic framework (MOF) material. Subsequently, the CuFe2O4 was incorporated into the MOF by a reduction-precipitation technique. The SrTiO3/CuFe2O4/MIL-101(Co) composite was synthesized by using hydrothermal in situ growth process. The XRD and FESEM investigations of the SrTiO3/CuFe2O4/MIL-101(Co) composite definitively verified its crystalline structure and proved its production with exact shape and dimensions. The data indicated that Candida albicans displayed the greatest vulnerability to all three produced materials, with reported Minimum Inhibitory Concentration (MIC) values of 500 µg mL−1 for MIL-101(Co). The CuFe2O4/MIL-101(Co) compound, when produced, exhibits MIC values of 200 µg mL−1. Additionally, the combination of CuFe2O4/MIL-101(Co) with SrTiO3, shows MIC values of 50 µg mL−1. The results also indicated that the MIC values for MIL-101(Co), and CuFe2O4/MIL-101(Co) against S. aureus were 100 µg mL−1. Ultimately, SrTiO3/CuFe2O4/MIL-101(Co) exhibited identical MIC values of 50 µg mL−1 against S. aureus. The concentration of the bacterial protein was increased by adding MIL-101(Co), CuFe2O4/MIL-101(Co), and SrTiO3/CuFe2O4/MIL-101(Co). The antibacterial capabilities of the SrTiO3/CuFe2O4/MIL-101(Co) were increased after being subjected to gamma doses of 100.0 kGy. This process paves a ways for manufacturing innovation in near future.

Enhanced antibacterial and genoprotective properties of nanoliposomal Satureja hortensis L. essential oil

Nanoliposomes are drug delivery systems that improve bioavailability by encapsulating therapeutic agents. The main objective of this study was to investigate the effects of nanoliposomal (NL) formulation on enhancing the bioavailability of essential oil. The essential oil of Satureja hortensis (SHO) was encapsulated in nanoliposomes (SHNLs). Physicochemical characterizations of NL formulations (size, charge, polydispersity index [PDI]) were evaluated by dynamic light scattering technique. The nanoliposome encapsulation efficiency (EE) was calculated as 89.90%. The prepared bionanosystems demonstrated significant antibacterial activities against Escherichia coli ATCC 10536, Pseudomonas aeruginosa ATCC 15442, and Staphylococcus aureus ATCC as determined by the agar diffusion method and microdilution tests. Minimum inhibitory concentration (MIC) values for SHNLs were found to be 5.187 µg/µL for E. coli and 2.59 µg/µL for both P. aeruginosa and S. aureus. Importantly, despite the lower substance content, both SHNLs and SHO exhibited comparable antibacterial activity against all tested strains. Furthermore, in order to determine the toxicity profile and possible effects on DNA damage or repair both the genotoxic and antigenotoxic effects of SHNLs were assessed using the cytokinesis-blocked micronucleus (CBMN) method in human lymphocyte cultures. The experimental data collectively indicate that the NL formulation of the S. hortensis essential oil enhances antibacterial activities and provides genoprotective effects against DNA damage. This highlights the significance of liposomal formulations of antioxidants in augmenting their biological activity. The results indicate that SHNLs can be a safe antibacterial agent for the pharmaceutical industry.

Antimicrobial Susceptibility of Various MRSA Clinical Isolates and the Impact of Glycopeptide MICs on Clinical and Microbiological Outcomes.

While vancomycin has remained the mainstay of the treatment for methicillin-resistant Staphylococcus aureus (MRSA) infections, there is growing evidence of the clinical impact of increased glycopeptide minimum inhibitory concentrations (MICs) in MRSA isolates. This study aimed to determine the susceptibility of various MRSA isolates to different antibiotics with antistaphylococcal activity and the impact of glycopeptide MICs on clinical and microbiological outcomes. This retrospective cohort study, conducted between 2013 and 2017, evaluated the susceptibility of MRSA strains isolated from various clinical samples to antistaphylococcal antibiotics using the gradient strip method. The clinical and laboratory features of patients infected with MRSA isolates with elevated glycopeptide MICs (>1 mg/L) and with isolates that had low glycopeptide MICs (≤1 mg/L) were compared. A total of 104 patients infected with MRSA strains were included in this study. Male sex (odds ratio [OR]=2.48, 95% confidence interval [CI]=1.01-6.10, p=0.048), two or more comorbidities (OR=2.48, 95% CI=1.03-6.50, p=0.044), history of MRSA infection (OR=4.91, 95% CI=1.70-14.28, p=0.003) and a longer hospital stay prior to MRSA infection (OR=2.32, 95% CI=1.05-7.85, p=0.040) were independent risk factors for high glycopeptide MICs. In MRSA infections with a teicoplanin MIC of >0.75mg/L, the microbiological and treatment failures were 46.2% (p=0.044) and 60.6% (p=0.042), respectively. This study showed that the critical MIC value, which suggested treatment failure as well as microbiological failure in the teicoplanin-treated MRSA infections, was >0.75 mg/L rather than >1 mg/L in our study cohort. The identification of high-risk patients;for treatment failures and mortality considering gradient strip method MIC values is crucial for the effective management of MRSA infections.

Evaluation of Antimicrobial Susceptibility and Resistance Patterns of Treponema denticola Isolated From Periodontal Disease: An In Vitro Study.

Background Periodontal disease poses a significant oral health challenge, involving inflammatory conditions impacting tooth-supporting structures. Treponema denticola, a "red complex" organism, plays a crucial role in periodontal pathogenesis, forming biofilms in subgingival environments and contributing to dysbiosis. Antimicrobial therapy is pivotal in managing periodontal disease, requiring a nuanced understanding of susceptibility patterns exhibited by key pathogens like T. denticola. Aims and objectives This study aims to investigate the antimicrobial susceptibility and resistance profiles of Treponema denticola, a prominent bacterium in periodontal disease, by examining its responses to various antimicrobial agents commonly used in periodontal therapy. Methodology Plaque samples were meticulously collected from individuals diagnosed with periodontal disease to ensure a diverse representation of the oral microbiome. All the samples were cultured, and red complex bacteria were isolated under anaerobic culture. Treponema denticola isolates were cultured from these samples under anaerobic conditions, and molecular techniques were employed for species identification. A comprehensive panel of antimicrobial agents was selected to assess the response of Treponema denticola. In vitro antimicrobial susceptibility testing (AST) was conducted using the antimicrobial gradient method, employing a hybrid approach combining elements of disk-diffusion and dilution methods. Results Treponema denticola had exhibitedresistance to metronidazole, a commonly used antibiotic effective against anaerobic bacteria, emphasizing limitations in its applicability. However, the bacterium displayed sensitivity to tetracycline, imipenem, cefoperazone, chloramphenicol, clindamycin, and moxifloxacin, offering diverse therapeutic options. The antimicrobial gradient strip test provided detailed minimum inhibitory concentration (MIC) values, contributing to a nuanced understanding of susceptibility and resistance patterns. Conclusion This study significantly advances our understanding of Treponema denticola's antimicrobial susceptibility and resistance profiles in the context of periodontal disease. The findings underscore the importance of tailored treatment strategies and contribute to broader efforts in antimicrobial stewardship, aligning with global initiatives to combat antibiotic resistance. This research lays the foundation for more effective and personalized approaches to periodontal care, emphasizing the intricate microbial dynamics associated with periodontal health and disease.

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.

Developing antibacterial peptides as a promising therapy for combating antibiotic-resistant Pseudomonas aeruginosa infections.

Antibiotic-resistant Pseudomonas aeruginosa poses a serious health threat. This study aimed to investigate the antibacterial activity of peptide KW-23 against drug-resistant P. aeruginosa and its potential for enhancing the efficacy of conventional antibiotics. KW-23 was synthesized from nine amino acids, specifically three tryptophans and three lysines. The purity of the substance was analyzed using reverse-phase high-performance liquid chromatography. The peptide was identified through mass spectrometry using electrospray ionization. The minimum inhibitory concentration (MIC) values of KW-23 in combination with conventional antibiotics against control and multidrug-resistant P. aeruginosa were determined utilizing broth microdilution. The erythrocyte hemolytic assay was used to measure toxicity. The KW-23 effect was analyzed using the time-kill curve. The peptide exhibited strong antibacterial activity against control and multidrug-resistant strains of P. aeruginosa, with MICs of 4.5 μg/mL and 20 μg/mL, respectively. At higher concentration of 100 μg/mL, KW-23 exhibited a low hemolytic impact, causing no more than 3% damage to red blood. The cytotoxicity assay demonstrates KW-23's safety, while the time-kill curve highlights its rapid and sustained antibacterial activity. The combination of KW-23 and gentamicin exhibited synergistic activity against both susceptible and resistant P. aeruginosa, with fractional inhibitory concentration index values of 0.07 and 0.27, respectively. The KW-23 synthesized in the laboratory significantly combats antibiotic-resistant P. aeruginosa. Due to its strong antibacterial properties and low toxicity to cells, KW-23 is a promising alternative to traditional antibiotics in combating multidrug-resistant bacteria.

Synthesis, Characterization, and Antibacterial Activity of Plant-Derived Zinc Oxide Nanostructure Using &lt;i&gt;Lavandula angustifolia&lt;/i&gt; and &lt;i&gt;Phyllanthus niruri&lt;/i&gt; 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.

Green Synthesis and Investigation of Antimicrobial Activity and Compressive Resilience of Glass Ionomer Cement Modified With Zirconia Nanoparticles: An In Vitro Study.

Background Glass ionomer cement (GIC) serves as a crucial biomaterial in dental restoration, offering applications in filling, lining, and adhesive procedures. Nevertheless, its mechanical properties often fall short, particularly in regions subjected to considerable stress. To address this issue, zirconia nanoparticles are incorporated at specific levels. Aim To assess the antimicrobial efficacy and compressive resilience of GIC modified with zirconia nanoparticles synthesized through green synthesis methods. Material and methods Zirconia nanoparticles were synthesized via a green method utilizing aloe vera extract in solvent form. These nanoparticles were then mixed into GIC at different concentration levels. Group I incorporated zirconia nanoparticles at a concentration of 3%, Group II at 5%, and Group III at 10%, while Group IV was the control, consisting of traditional GIC. Following that, samples were prepared and underwent characterization through various analytical techniques. The ability to inhibit microbial growth and the compressive resilience of the groups were examined. Microbial inhibition against the bacterial strains was assessed through minimum inhibitory concentration (MIC), and the ability to withstand compression was gauged by measuring the maximum force the specimen could endure before fracturing. Data underwent analysis with Statistical Package for the Social Sciences (IBM SPSS Statistics for Windows, IBM Corp., Version 24.0, Armonk, NY). Repeated measures of analysis of variance (ANOVA) were utilized to gauge average MIC values and compressive strength. Following this, Tukey's post hoc test was employed for pairwise comparisons. Results The findingsindicated, incorporating zirconia nanoparticles into GIC led to an improvement in its antimicrobial effectiveness, with a noticeable enhancement observed as the weight percent (% wt) of the additive increased. This improvement was notably noticeable in its effectiveness against Streptococcus mutans and Lactobacillus, exceeding that of the control with a noteworthy distinction. Furthermore, there were significant enhancements in compressive strength, in Group I (180.48 ± 1.02), Group II (191.25 ± 0.52), and Group III (197.52 ± 0.75), compared to Group IV (167.22 ± 1.235), with significant disparities (p < 0.05). Conclusion The research illustrates that introducing green-synthesized zirconia nanoparticles into GIC leads to heightened bactericidal potency and compressive resilience when contrasted with the control group (Group IV). Notably, the highest concentration of 10% demonstrated the most favourable antimicrobial attributes alongside enhanced strength. Consequently, integrating green-synthesized zirconia nanoparticles into GIC holds potential as a proficientmaterial. In future studies, there should be an exploration of molecular chemistry and bonding mechanisms to enhance our comprehension of its capabilities.