Minimum Inhibitory Concentration Method Research Articles

Phytochemical analysis and antibacterial activity of Washingtonia filifera (Lindl.) H. Wendl. fruit extract from Saudi Arabia

This work aimed to assess the antimicrobial potential of Washingtonia filifera extracts on some human pathogens. Agar well diffusion and minimum inhibitory concentrations (MIC) methods have been used to assess the antimicrobial activities of W. filifera extract against Staphylococcus aureus, Klebsiella pneumonia, Acinetobacter baumannii, Escherichia coli, and Candida albicans. Only the ethyl acetate (ETAC) and methanol extracts revealed antimicrobial activity against tested microorganisms. S. aureus appears to be the most sensitive microbes to the ETAC extract with equal inhibition zone (30 mm) and MIC (65 µg/mL) values. This is followed by K. pneumoniae, E. coli, and A. baumanni, respectively. The plant extract had different phytochemical constituents such as alkaloids, sterols, and polyphenols. Column chromatography of the ETAC extract resulted in the loss of inhibitory effect at the highest concentration tested (50 mg/mL) against tested microorganisms. The haemolytic activity of the different extracts was found in the following order: Hexane (83.57%) > ETAC (35.71%) > chloroform (23.57143) > methanol (0.71%) based on the highest concentration tested (8.3 mg/mL). In conclusion, ETAC extract was the most promsing extract among extracts tested. Secondary plant metabolites are of great value as natural antimicrobial agents.

In vitro activity of β-lactamase inhibitors avibanvctam and relebactam in combination with β-lactams against multidrug-resistant Mycobacterium tuberculosis and mutations of resistance genes

Objective: To evaluate the activity of six β-lactams in combination with three β-lactamase inhibitors against mycobacterium tuberculosis(MTB) in vitro. Methods: A total of 105 multidrug-resistant tuberculosis (MDR-TB) strains from different regions of Henan province from January to September 2020 were included in this study. Drug activity of six β-lactams (biapenem, meropenem, imipenem, doripenem, ertapenem and tebipenem) alone or in combination with β-lactamase inhibitors (clavulanic acid, avibactam and relebactam) was examined by minimum inhibitory concentration method (MICs) against 105 clinical isolates. Mutations of blaC, ldtmt1 and ldtmt2 were analyzed by PCR and DNA sequencing. Chi-square test was used to compare the antimicrobial activities of different β-lactam drugs. Results: Out of the β-lactams used herein, tebipenem was the most effective against MDR-TB and had an MIC50 value of 8 mg/L(χ2=123.70,P=0.001). Besides, after the addition of β-lactamase inhibitors, the MICs of most β-lactam drugs were reduced more evidently in the presence of avibactam and relebactam compared to clavulanic acid.Especially, relebactam decreased both the MIC50 and MIC90 of telbipenem by 16-fold, and diluted the MIC of 23 (21.90%) and 41 (39.04%) isolatesby 32-fold and 16-fold.In addition, a total of 13.33% (14/105) of isolates harbored mutations in the blaC gene, with three different nucleotide substitutions: AGT333AGG, AAC638ACC and ATC786ATT. For the strains with Ser111Arg and Asn213Thr substitution in BlaC, the MIC values of the meropenem-clavulanate combination were reduced compared with a synonymous single nucleotide polymorphism (SNP) group. Conclusions: Both avibactam and relebactam had better synergistic effects on β-lactams than clavulanic acid. The combination of tebipenem and relebactam showed the most potent activity against MDR-TB isolates. In addition, the Ser111Arg and Asn213Thr substitution of BlaC may be associated with an increased susceptibility of MDR-TB isolates to meropenem in the presence of clavulanate.

Effect of the Cross-Section Morphology in the Antimicrobial Properties of α-Ag2WO4 Rods: An Experimental and Theoretical Study

In this work, α-Ag2WO4 particles with different cross-sections were obtained using the co-precipitation method at different synthesis temperatures. The samples were characterized by X-ray diffraction (XRD), field-scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The antimicrobial activity was analyzed using the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) methods against the Escherichia coli and Salmonella spp. gram-negative bacteria. The antimicrobial tests against Escherichia coli and Salmonella spp. indicated that concentrations of 2.5–5 mg/mL and 5 mg/mL completely inhibit its growth, respectively. The antimicrobial activity was analyzed employing band-edge positions for ROS generations and the superficial distribution of Ag+ species that contribute to antimicrobial activity. Quantum-chemical calculations were used at the DFT level to investigate the surface-dependent reactivity of α-Ag2WO4, and we demonstrated how the antimicrobial properties could be tailored by the geometry and electronic structure of the exposed surfaces, providing guidelines for the morphology design.

Mineral composition, the profile of phenolic compounds, organic acids, sugar and in vitro antioxidant capacity, and antimicrobial activity of organic extracts of Juniperus drupacea fruits.

Juniperus drupacea fruit is widely used in traditional and complementary medicine in Turkey for the treatment of different diseases in various forms such as molasses and tar. This study was carried out to evaluate the phenolic compounds, organic acid, sugar, and macro- and micromineral distributions of methanol and water extracts of J. drupace fruit, as well as their antioxidant and antimicrobial potential. For this purpose, total phenolic content by spectrophotometer, phenolics, organic acids, and sugars distributions by HPLC in extracts of J. drupacea fruits, and macro- and micromineral element content by ICP-AES in fruit were determined. 2,2-diphenyl-l-picrylhydrazyl assay (DPPH assay) was used to evaluate in vitro antioxidant activity in extracts. The antimicrobial potential of J. drupacea fruit methanol extract against some gram-positive and gram-negative pathogenic bacteria was evaluated using disk diffusion and minimum inhibitory concentration (MIC) methods. The potassium macroelement and the iron microelement were found at high content in J. drupacea fruit. The total phenolic content in the methanol extracts was higher than the water extracts. Among the individual phenolic compounds, catechin, a flavonoid that was the highest in both extractions, was determined as 300.49 μg/g in methanol extract and 314.88 μg/g in water extract. DPPH scavenging activity was higher in methanol extracts. While the methanol extract of J. drupacea had no-inhibitory effect on the gram-negative bacteria tested, it exhibited a strong inhibition on the gram-positive bacteria Listeria innocua, Listeria monocytogenes, Staphylococcus carnosus, and Enterococcus faecalis.

High rate of multidrug resistance and integrons in Escherichia coli isolates from diseased ducks in select regions of China

With the increasing number of ducks being raised and consumed, it is crucial to monitor the presence of multidrug resistant (MDR) bacteria in duck farming. Waterfowl, such as ducks, can contribute to the rapid dissemination of antibiotic resistance genes (ARGs). The objective of this study was to investigate the antimicrobial resistance (AMR), ARGs, and mobile genetic elements (MGEs), such as IS26, tbrC, ISEcp1 in Escherichia coli(E. coli) isolated from the intestinal contents of diseased ducks between 2021 and 2022 in Sichuan, Chongqing and Anhui, China. The AMR phenotypes of 201 isolated E. coli strains were determined using the minimum inhibitory concentrations (MICs) method. Subsequently, polymerase chain reaction and sequencing techniques were employed to screen for integron-integrase genes (intI1, intI2, intI3 genes), gene cassettes (GCs), MGEs, and ARGs. The results demonstrated that 96.5% of the E. coli isolates were resistant to at least 1 antibiotic, with 88.1% of the strains displaying MDR phenotype. The highest AMR phenotype observed was for trimethoprim-sulfamethoxazole (88.1%). Furthermore, class 1 and class 2 integrons were detected in 68.2% and 3.0% of all the isolates, respectively, whereas no class 3 integrons were found. Ten types of GCs were identified in the variable regions of class 1 and class 2 integrons. Moreover, 10 MGEs were observed in 46 combinations, with IS26 exhibiting the highest detection rate (89.6%). Among the 22 types of ARGs, tetA (77.1%) was the most frequently detected. In the conjugational transfer experiment, transconjugants were found to carry specific ARGs and MGEs, with their MIC values were significantly higher than those of recipient E. coli J53, indicating their status as MDR bacteria. This study emphasizes the necessity of monitoring MGEs, ARGs, and integrons in duck farms. It provides valuable insights into the complex formation mechanisms of AMR and may aid in preventing and controlling the spread of MDR bacteria in waterfowl breeding farm.

The Zanthoxylum armatum fruit's oil exterminates Candida cells by inhibiting ergosterol biosynthesis without generating reactive oxygen species.

Candida spp. is a significant cause of topical and fungal infections in humans. In addition to Candida albicans, many non-albicans species such as C. krusei, C. glabrata, C. parapsilosis, C. tropicalis, C. guilliermondii cause severe infections. The main antifungal agents belong to three different classes, including azoles, polyenes, and echinocandins. However, resistance to all three categories of drugs has been reported. Therefore, there is an urgent need to search for other alternatives with antifungal activity. Many herbal extracts and compounds from natural sources show excellent antifungal activity. In this study, we used an oil extract from the fruits of Zanthoxylum armatum, which showed significant antifungal activity against various Candida spp. by two different methods-minimum inhibitory concentration (MIC) and agar diffusion. In addition, we attempted to explore the possible mechanism of action in C. albicans. It was found that the antifungal activity of Z. armatum oil is fungicidal and involves a decrease in the level of ergosterol in the cell membrane. The decrease in ergosterol level resulted in increased passive diffusion of a fluorescent molecule, rhodamine6G, across the plasma membrane, indicating increased membrane fluidity. The oil-treated cells showed decreased germ tube formation, an important indicator of C. albicans' virulence. The fungal cells also exhibited decreased attachment to the buccal epithelium, the first step toward invasion, biofilm formation, and damage to oral epithelial cells. Interestingly, unlike most antifungal agents, in which the generation of reactive oxygen species is responsible for killing, no significant effect was observed in the present study.

Antibacterial Activity of Boron Compounds Against Biofilm-Forming Pathogens.

This study aimed to evaluate the antibacterial activity of nine boron derivatives against biofilm-forming pathogenic bacteria. The effect of boron derivatives (CMB, calcium metaborate; SMTB, sodium metaborate tetrahydrate; ZB, zinc borate; STFB, sodium tetra fluorine borate; STB, sodium tetraborate; PTFB, potassium tetra fluor borate; APTB, ammonium pentabo-rate tetrahydrate; SPM, sodium perborate monohydrate; Borax, ATFB, ammonium tetra fluorine borate) on bacteria isolated from blood culture was determined by the minimum inhibitory concentration (MIC) method. Then, biofilm formation potentials on microplates, tubes, and Congo red agar were examined. The cytotoxicity of boron derivatives was determined by using WST-1-based methods. The interaction between the biofilm-forming bacteria, fibroblast cells, and boron derivatives was determined with the infection model. We found that the sodium metaborate tetrahydrate molecule was effective against all pathogens. According to the optical density values detected at 630nm in microplates, meticillin-resistant Staphylococcus aureus was observed to have the most substantial biofilm ability at 0.257nm. As a result of cytotoxicity studies, it has been determined that a 1µg/L concentration of boron derivatives is not toxic to fibroblast L929 cells. In cell culture experiments, these boron derivatives have very serious inhibitory activity against biofilm-forming pathogens in a short treatment period, such as 2-4h. Furthermore, using these molecules on inanimate surfaces affected by biofilms would be appropriate instead of living cells.

The Antimicrobial Properties of Malaysian Propolis as Intracanal Medicament in Endodontics

Numerous studies have shown that propolis, from the sting and stingless bees, possessed antimicrobial, antifungal, antidiabetic, antitumoral and antioxidant properties. Propolis produced by stingless bees, Heterotrigona itama, also possessed these properties but in varying intensity. Exploiting this natural product with antimicrobial properties against Enterococcus faecalis (EF), would be advantageous in endodontics. Particularly where the current synthetic medicament, calcium hydroxide (Ca(OH)2), failed to remove these bacteria, predominantly found in failed root canal-treated (RCT) teeth. The aims of this study are to determine the antimicrobial properties of Malaysian propolis (MP) against Enterococcus faecalis and to compare the antibacterial effect of MP with Ca(OH)2 as an intra-canal medicament. Raw propolis was purchased from Humaira Honey Sdn Bhd, Lenggong, Perak and the ethanolic extraction method was carried out until lyophilization. Antimicrobial susceptibility testing (AST) was done on five samples, namely, MP, Ca(OH)2, 2% chlorhexidine (CHX), 70% ethanol, and sterile normal saline (SDW), where CHX, 70% ethanol and SDW as controls. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) methods were carried out. The MIC and MBC for MP and CHX were done using the micro-dilution method on 96-well, while Ca(OH)2 were performed using the serial macro-dilution method. The results were analysed by Kruskal Wallis test with Mann-Whitney posthoc test and repeated-measures ANOVA with Bonferroni post hoc test (p <0.05). The mean MIC from three trials that were carried out on the samples was CHX (<0.008%) < MP (0.03%) < Ca(OH)2 (0.62%). While the MBC values for three trials were found to be CHX (0.011%) < MP (0.07%) < Ca(OH)2 (1.25%). In conclusion, MP was shown to be antibacterial and effective against Enterococcus faecalis and is more effective when compared to Ca(OH)2, which is commonly used as an intra-canal medicament. Further research is needed to test MP’s clinical efficacy.

Pyrolized Diatomaceous Biomass Doped with Epitaxially Growing Hybrid Ag/TiO2 Nanoparticles: Synthesis, Characterisation and Antibacterial Application.

In the pursuit of innovative solutions for modern technologies, particularly in the design and production of new micro/nanostructured materials, microorganisms acting as "natural microtechnologists" can serve as a valuable source of inspiration. This research focuses on harnessing the capabilities of unicellular algae (diatoms) to synthesize hybrid composites composed of AgNPs/TiO2NPs/pyrolyzed diatomaceous biomass (AgNPs/TiO2NPs/DBP). The composites were consistently fabricated through metabolic (biosynthesis) doping of diatom cells with titanium, pyrolysis of the doped diatomaceous biomass, and chemical doping of the pyrolyzed biomass with silver. To characterize the synthesized composites, their elemental and mineral composition, structure, morphology, and photoluminescent properties were analysed using techniques such as X-ray diffraction, scanning and transmission electron microscopy, and fluorescence spectroscopy. The study revealed the epitaxial growth of Ag/TiO2 nanoparticles on the surface of pyrolyzed diatom cells. The antimicrobial potential of the synthesized composites was evaluated using the minimum inhibitory concentration (MIC) method against prevalent drug-resistant microorganisms, including Staphylococcus aureus, Klebsiella pneumonia, and Escherichia coli, both from laboratory cultures and clinical isolates.

Resistance patterns of bacterial pathogens causing lower respiratory tract infections: Aleppo-Syria.

This study aimed to scan the bacterial spectrum causing LRTIs, their susceptibility profile and patient related risk factors. Two hundred sixty-eight specimens from LRTIs suspected patients attending University Hospital were collected. Specimens included bronchial washings, transtracheal aspiration samples and sputum. After appropriate culture and identification tests, susceptibility test was done using minimum inhibitory concentration method. Data were collected from patients for further analysis. of total specimens, 150 showed positive culture results (Acinetobacter baumannii, Pseudomonas aeruginosa, Citrobacter koseri, Escherichia coli, Klebsiella pneumonia, Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus haemolyticus, Streptococcus pneumonia and Candida spp.). The antibiogram showed high resistance among all bacterial isolates against most antibiotics. Good susceptibility rates were shown to colistin in Gram-negative group and piperacillin\tazobactam in Gram-positive group. Trimethoprim\sulfamethoxazole showed good susceptibility results in both groups. Many factors showed correlation with LRTIs such as age (P=0.004), smoking (P=0.049), residency (P=0.043), hypertension (P=0.012), lung chronic disease (P=0.007) and cancer (P=0.048). The leading cause of LRTIs in our study were A. baumannii and P. aeruginosa which both are very troublesome pathogens and multidrug resistant frequency was alarming. Random empirical antibiotic using can highly lead to increased resistance. Further care must be taken after patients with risk factors, and adjustments should be done to those modifiable factors.

Pneumococcal serotypes and antibiotic resistance in healthy carriage children after introduction of PCV13 in Lima, Peru

ObjectiveTo determinate the frequency of Streptococcus pneumoniae nasopharyngeal carriers, serotypes and antimicrobial resistance in healthy children in Lima, Peru, post-PCV13 introduction and to compare the results with a similar study conducted between 2006 and 2008 before PCV7 introduction (pre-PCV7). MethodsA cross-sectional multicenter study was conducted between January 2018 and August 2019 in 1000 healthy children under two years of age. We use standard microbiological methods to determinate S. pneumoniae from nasopharyngeal swab, Kirby Bauer and minimum inhibitory concentration methods to determinate antimicrobial susceptibility and whole genomic sequencing to determinate pneumococcal serotypes. ResultsThe pneumococcal carriage rate was 20.8 % vs. 31.1 % in pre-PCV7 (p < 0.001). The most frequent serotypes were 15C, 19A and 6C (12.4 %, 10.9 % and 10.9 % respectively). The carriage of PCV13 serotypes after PCV13 introduction decreased from 59.1 % (before PCV7 introduction) to 18.7 % (p < 0.001). Penicillin resistance was 75.5 %, TMP/SMX 75.5 % and azithromycin 50.0 %, using disk diffusion. Penicillin resistance rates using MIC breakpoint for meningitis (MIC ≥ 0.12) increased from 60.4 % to 74.5 % (p = 0.001). ConclusionThe introduction of PCV13 in the immunization program in Peru has decreased the pneumococcal nasopharyngeal carriage and the frequency of PCV13 serotypes; however, there has been an increase in non-PCV13 serotypes and antimicrobial resistance.

Antioxidant and Antibacterial Activities of Ethanol Extract of Matoa (Pometia pinnata) Leaves

A Plants used for traditional medicine are matoa (Pometia pinnata). This plant is spread in almost every area in the province of Papua. The use of plants as medicinal ingredients is closely related to the content of chemical compounds contained in these plants, especially related to the active compounds contained in plants. Based on previous research, matoa leaf extract contains alkaloids, flavonoids, steroids, tannins, glycosides, and saponins. This study aims to determine the antioxidant and antibacterial activity of Pometia pinnata leaf extract. In the early stages of this research, the extraction process was carried out using the reflux method using ethanol solvent, testing the antioxidant activity using the DPPH and ABTS methods, as well as total phenol and flavonoids. Meanwhile, testing the antibacterial activity with the Minimum Inhibitory Concentration method against Staphylococcus aureus and Pseudomonas aeruginosa. From the results of the antioxidant activity test, the IC50 value was obtained in the DPPH method of 41.83 ± 0.17 µg/mL and also in the antibacterial test, it could inhibit the growth of Staphylococcus aureus and Pseudomonas aeruginosa bacteria

Antimicrobial resistance in foodborne &lt;i&gt;Salmonella enterica&lt;/i&gt; isolates in the Republic of Belarus

Introduction. Antimicrobial resistance is a global public health concern. Salmonella spp., which can be transmitted to humans through contaminated food, are among the most important foodborne pathogens worldwide.&#x0D; Materials and methods. The antimicrobial resistance of 358 bacterial isolates collected from food and water in the Republic of Belarus (Belarus) in 20182021 was studied by analyzing phenotypic and genotypic characteristics of antibiotic bacterial resistance. MALDI-TOF mass spectrometry was used to classify and identify bacteria. Phenotypic antimicrobial susceptibility of bacteria was measured by the minimum inhibitory concentration method using a Sensititre automated bacteriological analyzer and the disk diffusion test for 45 antimicrobial agents. Antimicrobial resistance genes in multidrug-resistant Salmonella isolates were identified by whole-genome sequencing.&#x0D; Results. The in vitro testing of phenotypic bacterial susceptibility showed high susceptibility to fluoroquinolones (97.2%), third-generation cephalosporins (93.9%), carbapenems (98.0%), ampicillin (81.8%), aminoglycosides (97.5%), tetracyclines (87.5%), chloramphenicol (93.8%), trimethoprim/sulfamethoxazole (co-trimoxazole) (95.3%) and colistin (85.2%). It was found that the antibiotic resistance mechanism in S. enterica was associated with the presence of genes blaTEM-1B (82%), blaTEM-1C (7.7%), blaSHV-12 (2.6%), blaDHA-1 (2.6%), blaCMY-2 (7.7%), qnrB2 (9.1%), qnrB4 (9.1%), qnrB5 (9.1%), qnrB19 (72.7%), aac(6)-Ib-cr (9.1%), aac(6)-Iaa (100%), aadA1 (13.2%), aadA2 (8.8%), tetB (74.3%), tetA (25.7%), tetM (2.9%), tetD (28.6%), mcr-9 (1.5%).&#x0D; Conclusion. All the bacterial isolates were phenotypically susceptible to first-line antibiotics used in treatment of salmonellosis: fluoroquinolones and third-generation cephalosporins. The whole-genome sequencing of multidrug-resistant Salmonella isolates (19.0%) detected resistance genes for 9 groups of antibiotics: aminoglycosides (100%), beta-lactams (57.4%), fluoroquinolones (16.2%), tetracyclines (51.5%), macrolides (1.5%), phenicols (30.4%), trimethoprim (13.0%), sulfonamides (47.8%) and colistin (1.4%). Thus, epidemiological surveillance of the Salmonella spread through the food chain is of critical importance for the monitoring of antimicrobial resistance among foodborne Salmonella.

Chalcone Schiff bases disrupt cell membrane integrity of Saccharomyces cerevisiae and Candida albicans cells.

Chalcones have a variety of cellular protective and regulatory functions that may have therapeutic potential in many diseases. In addition, they are considered to affect key metabolic processes in pathogens. Nevertheless, our current knowledge of the action of these compounds against fungal cell is scarce. Therefore, in this study, various substituted chalcone Schiff bases were investigated to reveal their cellular targets within the yeasts Saccharomyces cerevisiae and Candida albicans. First, their antifungal activities were determined via minimum inhibitory concentration method. Surprisingly, parent chalcone Schiff bases showed little or no antifungal activity, while the nitro-substituted derivatives were found to be highly active against yeast cells. Next, we set out to determine the cellular target of active compounds and tested the involvement of the cell wall and cell membrane in this process. Our conductivity assay confirmed that the yeast cell membrane was compromised, and that ion leakage occurred upon treatment with nitro-substituted chalcone Schiff bases. Therefore, the cell membrane came to the fore as a possible target for the active chalcone derivatives. We also showed that exogenous ergosterol added to the growth medium reduced the inhibitory effect of chalcones. Our findings open up new possibilities for the design of future antimicrobial agents based on this appealing backbone structure.

INVESTIGATION OF CHEMICAL CONTENT AND ANTIMICROBIAL ACTIVITIES OF DIFFERENT PLANT SOURCES OF ANATOLIAN PROPOLIS SAMPLES

The ethnopharmacological approach combined with chemical and biological methods can be a useful model in the field of pharmacology. One of these approaches, apitherapy, is the use of bee and hive products for therapeutic purposes. Propolis is among the best known of these bee products. The chemical composition of propolis varies according to the local or endemic flora, bee species, geographical origin and season. This study is to determine the antimicrobial activity differences between chestnut and polyfloral origin propolis against various pathogenic bacterial species. First of all, the Liquid Chromatography-Mass Spectrometry (LC-MS/MS) method was used for the determination of bioactive components known to be responsible for antimicrobial activity. Folin-Ciocalteu method and colorimetric aluminum chloride assay were used to determine the total phenolic (TP) and flavonoid (TF) amounts. 19 different pathogenic microorganisms were selected to test the antimicrobial activity levels of propolis samples with agar well diffusion and minimum inhibitory concentration (MIC) methods. TP and TF values of chestnut propolis (71.06 mg GAE/mL-11.75 mg QE/mL) were significantly higher than polyfloral sample (36.84 mg GAE/mL-7.04 mg QE/mL). Chrysin, a flavone derivative, was the most abundant compound in both samples. The MIC values of chestnut propolis ranged from 19.5 to 2500 µg/mL, while the MIC value of polyfloral origin propolis was between 39.06 and 5000 µg/mL. The most susceptible strain was Mycobacterium smegmatis for both samples with different concentration. Notably, it was observed that the botanical origins affect the chemical composition of propolis, and this situation can also be effect antibacterial and antifungal activity in respective propolis because of the different amount and diversity of bioactive compounds. Consequently, chestnut propolis is a promising candidate for drug discovery that can be used to treat some infectious diseases, including diseases related with resistant bacteria.

Pharmacological assessment of Co3O4, CuO, NiO and ZnO nanoparticles via antibacterial, anti-biofilm and anti-quorum sensing activities.

Infectious diseases have risen dramatically as a result of the resistance of many common antibiotics. Nanotechnology provides a new avenue of investigation for the development of antimicrobial agents that effectively combat infection. The combined effects of metal-based nanoparticles (NPs) are known to have intense antibacterial activities. However, a comprehensive analysis of some NPs regarding these activities is still unavailable. This study uses the aqueous chemical growth method to synthesize Co3O4, CuO, NiO and ZnO NPs. The prepared materials were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction techniques. The antibacterial activities of NPs were tested against Gram-positive and Gram-negative bacteria using the microdilution method, such as the minimum inhibitory concentration (MIC) method. The best MIC value among all the metal oxide NPs was 0.63 against Staphylococcus epidermidis ATCC12228 through ZnO NPs. The other metal oxide NPs also showed satisfactory MIC values against different test bacteria. In addition, the biofilm inhibition and antiquorum sensing activities of NPs were also examined. The present study presents a novel approach for the relative analysis of metal-based NPs in antimicrobial studies, demonstrating their potential for bacteria removal from water and wastewater.

Synthesis, characterization and pharmacological studies of cobalt(II), nickel (II) and copper (II) complexes of thiazole schiff bases

Many Schiff bases prepared from 2-hydrazinobenzothiazole and isatin have been used to produce Co (II) complexes of the form [ML2]Cl2. Nitrogen from azomethine, oxygen from lactonyl, and nitrogen atoms of the thiazole ring contribute to coordinating the metallic ion. Complexes made entirely of metal have geometrical octahedrons, according to analytical, magnetic studies and spectroscopic (Infrared, Ultraviolet-Visible, ESR, FAB-mass) investigations. The conductivity measurements show the electrolytic behaviour of the metal complexes. The redox behaviour of the metal complexes is investigated using cyclic voltammetry. The antibacterial and antifungal activities of the Schiff bases and their metal complexes were examined using the Minimum Inhibitory Concentration method against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and S. typhi. Investigations into DNA cleavage were conducted using the agarose gel electrophoresis technique, and significant DNA cleavage was found.

Simultaneous green synthesis of Magnetite-Nanoparticles MNPs using microalgae Spirulina sp. for antibacterial activity

Biosynthesize of Magnetic Nanoparticles MNPs is the environmentally friendly synthesis of nanoparticles that can be used as an alternative to commercially available antibiotics. The present study aimed to determine the ability of biosynthesized magnetic nanoparticles of Spirulina sp. for antibacterial activity. Microalgae isolated from the Gomaspan river cultured on BG11 medium and, is identified using morphology and molecular method and the optimum growth rate of microalgae studied, the biomass used to synthesize of MNPs then was characterized by a visible color change and Scanning electron microscope SEM, FTIR with XRD. Antimicrobial activity of Spirulina sp. and biosynthesize of MNPs. studied using different extracts (ethanol, methanol and Diethyl ether) against growth of Salmonella Typhi, Streptococcus pyogenes, Escherichia coli and pseudomonas aerogenes by disc diffusion and Minimum inhibitory concentration methods. The antibacterial activity from microalgae Spirulina sp. and biosynthesized MNPs from Spirulina sp. showed to inhibit growth of bacteria with both methods and the higher inhibition zone showed as (30-37mm). The minimum inhibition concentration showed with ethanol extract (125-500 µg/l). The current study is first report an eco-friendly and convenient method for the synthesis of MNPs using Microalgae Spirulina sp. extracts. This biosynthetic process might be useful pharmaceuticals, and medicine treatment of pathogenic bacteria. Keywords: Nanoparticle, Magnetic, Spirulina, Antibacterial, solvent extract

Investigation of composition, antioxidant, antimicrobial and cytotoxic characteristics from Juniperus sabina and Ferula communis extracts

Plants have been one the most valuable sources of biologically active compounds. This study investigates the chemical composition, as well as the antioxidant, antimicrobial, and cytotoxic activities of methanolic and ethanolic extracts from Juniperus sabina and Ferula communis leaves, grown in Cyprus. Total phenolic and flavonoids content of methanol and ethanol extracts were quantified. Chemical constituents of the leaf extracts were analysed using gas chromatography/mass spectrometry (GC/MS). Mome inositol was the predominant component in the J. Sabina’s extracts. The most dominant component in F. communis ethanolic extract was phytol, while in FCL methanolic extract 1,3,4,5 tetrahydroxycyclohexanecarboxylic acid. Antioxidant activities were evaluated by 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical-scavenging ability. Antioxidant activity results revealed concentration dependent activity for methanolic and ethanolic extracts from the plant leaves. Antibacterial activity of plant extracts was tested against Gram-negative and Gram-positive bacteria using disk diffusion and minimal inhibitory concentration methods. Cytotoxic activity of plant extracts were evaluated on MCF-7 and MDA-MB-231 breast cancer cell lines, where they demonstrated their potential on the viability of both cell lines. The biological activity revealed by plants is due to the bioactive compounds found in the extracts. These bioactive components could be used as anticancer drug candidates.

SPECIATION AND ANTIMICROBIAL SUSCEPTIBILITY OF ENTEROCOCCI FROM PATIENTS IN A TERTIARY CARE HOSPITAL

Introduction: Enterococci have evolved from normal commensals to multidrug resistant pathogen. Enterococci are often reported in association with hospital-acquired infections. Management of Enterococcal infections has become challenging due to the emergence of multidrug resistant strains. Objectives: To speciate and detect the antibiotic susceptibility of Enterococci isolated from different clinical specimens.Materials and Methods: Atotal of 100 Enterococci strains isolated from clinical samples were tested using standard microbiological procedures. The minimum inhibitory concentration (MIC) for vancomycin was tested by agar dilution and E-strip methods. Results: Enterococci infections were more common in age groups, 21-40 years and 41-60 years with male preponderance. Isolates of Enterococci were more frequently associated with post operative wound infection (26%). E. faecalis (55%) was the predominant species, followed by E. faecium (45%). E. faecium showed 80% resistance to penicillin and ampicillin, while E. faecalis showed 38% resistance. All Enterococci isolates were 100% sensitive to vancomycin, linezolid and teicoplanin by the disc diffusion method; however, MIC for vancomycin by agar dilution and E-strip methods showed one strain of E. faecium resistant to vancomycin. Conclusion: Enterococci identication to the species level should be stressed in routine laboratory practice. Vancomycin resistance detection in Enterococci by the MIC method should be preferred as it helps reduce the morbidity and mortality due to Vancomycin resistant Enterococci.