Minimum Bacteriostatic Concentration Research Articles

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.

Design and Synthesis of Polyacrylamide Quaternary Ammonium Salt with Antibacterial Activity

Propenamine quaternary ammonium salt (NNDBAB) containing unsaturated bonds was synthesized from propenamine and bromobutane by alkylation reaction. Using NNDBAB as a monomer, PNNDBAB was further self-polymerized by free radical polymerization to produce propenamine quaternary ammonium salt (PNNDBAB). The structure of NNDBAB was characterized by infrared spectroscopy and nuclear magnetic resonance spectroscopy. The antibacterial properties of PNNDBAB were characterized by an antibacterial zone test, minimum inhibitory concentration, and smear plate counting. The results showed that PNNDBAB had good bacteriostatic activity, the diameter of the bacteriostatic zone was 27 mm, the minimum bacteriostatic concentration was 0.5 mg/L, and the bacteriostatic rate of 1wt% was 71.0%. The bacteriostatic effect was significant. The antibacterial effect of PNNDBAB is long-lasting. When added to the emulsion, the antibacterial effect of PNNDBAB can be sustained within 15 days.

New Chalcone Derivatives Containing 2,4-Dichlorobenzenesulfonamide Moiety with Anticancer and Antioxidant Properties.

Chalcones and their derivatives, both natural and synthetic, exhibit diverse biological activities. In this study, we focused on designing and synthesizing (E)-2,4-dichloro-N-(4-cinnamoylphenyl)-5-methylbenzenesulfonamides 4-8 with the following two pharmacophore groups: 2,4-dichlorobenzenesulfonamide and chalcone. The obtained compounds displayed notable anticancer effects on various human cancer cells, such as cervical HeLa, acute promyelocytic leukemia HL-60, and gastric adenocarcinoma AGS, when assessed with the MTT test. The activity of all compounds against cancer cells was significant, and the obtained IC50 values were in the range of 0.89-9.63 µg/mL. Among all the tested compounds, derivative 5 showed the highest activity on the AGS cell line. Therefore, it was tested for cell cycle inhibition, induction of mitochondrial membrane depolarization, and activation of caspase-8 and -9. These results showed that this compound strongly arrested the cell cycle in the subG0 phase, depolarized the mitochondrial membrane, and activated caspase-8 and -9. Similar to the anticancer effects, all the obtained compounds 4-8 were also assessed for their antioxidant activity. The highest antiradical effect was demonstrated for derivative 5, which was able to inhibit DPPH and ABTS radicals. All examined compounds showed dose-dependent activity against neutrophil elastase. Notably, derivatives 7 and 8 demonstrated inhibitory properties similar to oleanolic acid, with IC50 values of 25.61 ± 0.58 and 25.73 ± 0.39 µg/mL, respectively. To determine the antibacterial activity of derivatives 4-8, the minimum bacteriostatic concentration (MIC) values were estimated (>500 µg/mL for all the tested bacterial strains). The findings demonstrate the substantial potential of sulfonamide-based chalcone 5 as a promising drug in anticancer therapy.

Cefoperazone rapidly and sensitive quantitative assessment via a validated RP-HPLC method for different dosage forms, in-use stability, and antimicrobial activities

Cefoperazone (Cfz) is a member of the third generation of parenteral cephalosporin antibiotics. It is used on a wide scale in prescribed antibiotic drugs as anti-infection, especially for Gram-negative and also against Gram-positive microorganisms. The current study aimed to find a rapid RP-HPLC method of Cfz analysis with high linearity, repeatability, sensitivity, selectivity, and inexpensive. In our developed method, there is no need to use special chemical reagents, a high percentage of organic solvent, a high flow rate, further guard column. The chromatographic system comprises an ODS column (150 mm × 4.6 mm × 5 μm). The mobile phase was prepared by mixing KH2PO4 solution: acetonitrile (80:20) with a flow rate of 1.0 mL/min at detection wavelength 230 nm, at room temperature using injection volume 20 μL. The method manifested a satisfied linearity regression R2 (0.9993) with a good repeatability range (0.34–0.92%) with LOD and LOQ; 4.04 μg/mL and 12.24 μg/mL respectively. The method proved its efficiency via system suitability achievement in the robustness and ruggedness conduction according to the validation guidelines. The shorter analysis time makes the method very valuable in quality control to quantify the commercial Cfz in pharmaceutical preparations. This improved HPLC method has been successfully applied for Cfz analysis for Peracef and Peractam vials in our routine finished and stability studies testing laboratories. Additionally, the detection limit of Cfz has been tested in our quality control lab to detect the smallest amount of traces that may be present after the cleaning process of the production machines for cephalosporins preparations. In a precedent for the first time, we were able to use the current analysis method to determine the minimum inhibitory concentration (MIC) and minimum bacteriostatic concentration (MBC). The conventional broth micro-dilution tube method was used to determine MIC at 250 µg/mL and MBC at 125 µg/mL of Cfz against the standard strain of Burkholderia cepacia (B. cepacia) ATCC 25416 as Gram-negative bacteria in vitro.

Application Study of Novel Eggshell/Ag Combined with Pit and Fissure Sealants.

The study aims to enhance the anti-caries performance of pit and fissure sealants through the synthesis of novel silver nanocomposites, and to evaluate their mechanical properties and biological safety in vitro and in vivo. The antibacterial properties of synthetic eggshell/Ag were detected by bacterial inhibition zone, minimum bacteriostatic concentration, fluorescence staining and scanning electron microscopy. The synthetic products were then combined with pit and fissure sealants to prepare specimens, and their effects on mechanical properties, antibacterial properties and cytotoxicity were evaluated. Furthermore, an oral mucosal contact model of golden hamsters was established according to the ISO10933 standard to evaluate local stimulation and systemic effects. The novel nanocomposite eggshell/Ag was confirmed to exhibit strong broad-spectrum antibacterial activity, and that the eggshell/Ag-modified pit and fissure sealant had strong antibacterial properties against common dental caries bacterial biofilms, without any significant change in mechanical properties. The gradient dilution extract showed acceptable cytotoxicity, and in the golden hamster oral contact model, there were no visible abnormalities in local mucosal tissues, blood indices, or liver and kidney histopathology. These findings suggest that eggshell/Ag combined with pit and fissure sealants has strong antibacterial activity and excellent biosafety in vitro and in vivo, making it a promising candidate for clinical applications.

PH-Responsive Intelligent Antibacterial Coatings Based on 2D-COF for Controlled Release of Capsaicin

Herein, we designed and synthesized a two-dimensional covalent organic framework (2D-COF) of a Schiff base using a mechanical chemical grinding method. Moreover, capsaicin@chitosan (CAP@CS) microcapsules were loaded on a TpPa-1 COF by a physical adsorption method to prepare composites (CAP@CS/TpPa-1), which realized the pH-sensitive controlled release of the fungicide CAP, dispersed in fluorocarbon resin to prepare an intelligent coating with environmentally friendly long-term antifouling performance. TpPa-1 improves the antibacterial efficiency by increasing the dispersity of CAP@CS in the resin. Therefore, a CAP release amount of 2 wt % composite coating can meet the minimum bacteriostatic concentration of 37.5 μg/mL required for antifouling. Importantly, pH-responsive controlled release caused by the protonation of CS and the electrostatic interaction between CAP@CS and TpPa-1 COF and increased bacterial contact area by CAP@CS reunion inhibited by TpPa-1 COF improve the bactericidal efficiency of the composite. The composite coating has excellent corrosion resistance, mainly because COF extends the propagation path of the corrosive medium.

SELECTION OF DECAMETHOXINE RESISTANT VARIANTS OF MICROORGANISMS WHILE USING QUATERNARY AMMONIUM COMPOUNDS UNDER CLINICAL CONDITIONS FOR 50 YEARS (1972-2022)

Antiseptic decamethoxine (decasan), which belongs to quaternary ammonium compounds,has been used in the form of aqueous, aqueous- alcoholic, alcoholic, aqueous- glycerin, and glycerin solutions in clinical practice since 1969. Experimental studies of theformation rate of Staphylococci (S. aureus 209-Р, S. epidermidis) resistance showed thatover 30 passages, the resistance of Staphylococci increases 16-64 times, which indicatesthe possibility of formation of resistant forms of microbiota in relation to decamethoxineantiseptic in clinical conditions.Purpose of the work – to analyze the formation of opportunistic resistance of microbiota,the causative pathogens of infectious and inflammatory processes, over a period of 50years of local application in clinical conditions of the antiseptic decamethoxine – dekasanin the departments of a surgical profile (surgical, gynecological, otorhinolaryngological,etc.).Materials and methods. Analysis of sensitivity to the antiseptic decamethoxine[1, 10-Decamethylene-bis (N1, N1-dimethylmentoxycarbonylmethyl) – ammoniumdichloride], which belongs to quaternary ammonium compounds was carried out inrelation to isolated and identified clinical and reference global strains of opportunisticmicroorganisms belonging to different taxonomic groups of bacteria and yeast-likefungi of the genus Candida. The level of antimicrobial activity was determined by themethod of successive two-fold serial dilutions in a liquid environment optimal for the testmicrobe. The establishment of bacteriostatic (fungistatic) and bactericidal (fungicidal)concentrations of the antiseptic was repeated three times.Results. The sensitivity of the reference test strains remained practically unchangedin the minimum bacteriostatic concentration for 50 years. The minimum bacteriostaticconcentration of decamethoxine in relation to clinical strains of S. aureus, over 50 yearsof use – increased by 13.46 times, and in relation to S. epidermidis – by 8.14 times. Thesensitivity of clinical strains of S. pyogenes was reduced by 5.42-3.63 times; as for S.anginosus, resistance to decamethoxine increased by 3.07-1.62 times. Clinical strainsof S. mitis, which is mainly responsible for the formation of dental caries, also acquiredresistance by 2.21-2.62 times, respectively, and the resistance of E. faecalis increased by3.10-1.90 times. The resistance of C. albicans increased by more than 2 times during thestudied period, and C. tropicalis – by 1.94 times.Conclusions. The antibacterial activity of decamethoxine (decasan) against standardtest strains of bacteria of the genera Staphylococcus, Streptococcus, Escherichia,Pseudomonas, and yeast-like fungi of the genus Candida is stable when these test strainsare stored in laboratory conditions without contact with an antiseptic for 50 years. The useof the antiseptic decamethoxine (decasan) in clinical conditions for 50 years (1972-2022)leads to the formation of different levels of resistance of gram-positive (2.21-13.46 timesincrease in the minimum bacteriostatic (MBsC) concentration) and gram-negative(increase of MBsC 1,25-3.38 times, MBcC 1.49-2.21 times) of bacteria. Decamethoxineresistant variants of yeast-like fungi of the genus Candida are slowly formed. Fungistaticresistance increases 1.94-2.23 times, fungicidal resistance 1.73-2.09 times. The resistanceof bacteria and yeast-like fungi of the genus Candida to decamethoxine (decasan) developsby mutation after short-term, single and multiple contacts in clinical conditions withoutnoticeable changes in the biological characteristics of bacteria (Staphylococcus), whichmakes it possible to state that mutations are not directional and are not associated withan antiseptic, and play the role of only a selective agent.

Urinary Tract Pathogens: Analysis and Antimicrobial Effects of Ocimum Gratissimum Leaf

The search for alternative medicine for the treatment of pathogenic organisms associated with urinary tract infection (UTI) is on increase. The study was carried out to determine the antimicrobial activities of Ocimum gratissimum leaf extracts on three urinary tract pathogens; Escherichia coli, Staphylococcus aureus and Candida albicans, using their corresponding standard oganisms as controls. The phytochemical analysis of aqueous and alcoholic contents of Ocimum gratissimum leaf extracts revealed the presence of; alkaloids, carbohydrates, flavonoids, glycosides, phenolics, saponins, steroids, and tannins. The minimum inhibitory concentration (MIC), minimum bacteriostatic concentration (MBC) and minimum fungustatic concentration (MFC) of the extracts tested on the three uropathogens was 62.5 to 125 mg/ml. The ethanolic extracts at the concentration of 500mg/ml exhibited strong activity against the urinary pathogens with maximum zones of inhibitions of 23.5±1.5, 23.6±0.6 and 18.25±1.3mm while the aqueous extracts at the same concentration showed weak antimicrobial activity at 3.5±0.5mm as the highest zone of inhibition and 1.4±0.0mm as the lowest zone of inhibition. Notably, the inhibition zones increased with increase in extracts concentration and decreased with decrease in the concentration of extracts. Meanwhile, 12 fractions were eluted from O. gratissimum leave extract. The major phytochemical fractions were mainly alkaloids, flavonoid, and saponins. This study showed that the ethanolic extracts of Ocimum gratissimum is a good antimicrobial agent in-vitro and should not be neglected as an alternative medicine for treatment of pathogenic UTIs

Antibacterial and phytochemicals status of <i>Detarium microcarpum</i> (guill and perr) stem bark

The study aimed to provide confirmatory status on traditional usage of <i>Detarium microcapum</i> against urinary and intestinal infections and serve as an alternative in fighting against multi-drug resistance. Hence, the determination of chemical constituents of stem bark using GC-MS because of its sensitivity and high resolving power in identifying compounds, and test the antibacterial potential of methanol crude extract on some bacteria associated with the diseases claimed to be treated by traditional healers. Bacterial isolates were collected, and zone of inhibition diameter (ZID), minimum inhibition concentration (MIC), minimum bactericidal concentration (MBC) and minimum bacteriostatic concentration (MBS) were conducted to determine antibacterial activity. At the same time, gas chromatography coupled with mass spectrometry (GC-MS) was used to identify the phytoconstituents. The mean ZID (mm) ranged from 17.3±21 to 20.0±35 mm and showed a statistical significance difference at P< 0.05 for <i>S. aureus</i>, <i>E. coli</i>, and <i>K. pneumonia</i>. The MIC ranged from 11.67±7.6 to 4.17±1.4 mg/L, MBS 16.67±5.8 to 5.00±00, MBC 20.0±00 to 5.0±00, in order of increasing concentrations. Inspection of the MBC/MIC ratio indicated a bactericidal effect across isolates. From the GC-MS analysis, twenty-six phytochemical constituents were identified, primarily fatty acids or their esters. Chemical constituents' from <i>D. microcapum</i> methanol crude extract were identified. The antibacterial activity of some compounds directly correlates with the bioactivity of the same isolated and tested elsewhere, from a different source, thus its potential and therefore supporting the claim for its traditional usage. The research recommends in-depth research toward identifying specific active compounds for public health solutions.

Ciprofloxacin stress changes key enzymes and intracellular metabolites of Lactobacillus plantarum DNZ-4

Ciprofloxacin (CIP) is an antibiotic used to treat infections caused by bacteria. In this experiment, key enzymes and intracellular metabolites of Lactobacillus plantarum DNZ-4 was researched under CIP stress. The results showed that the activities of hexokinase, pyruvate kinase, β-galactosidase and Na+, K+-ATPase after 1/2 minimum bacteriostatic concentration (MIC) CIP treatment were significantly decreased (P<0.01). Gas chromatography-mass spectrometry was used to analysis the changes of main metabolites in the cells and principal component analysis and partial least square model were constructed. The results indicated that CIP could cause changes in intracellular fatty acids, carbohydrates and amino acids, and the mechanism of amino acid metabolism under CIP stress was significantly inhibited. L. plantarum DNZ-4 made stress response to CIP by regulating the ratio of saturated fatty acids and unsaturated fats. This experiment revealed the changes of growth and metabolism mechanism of L. plantarum DNZ-4 under CIP stress, which help to provide technical means for the development of effective probiotics preparation products.

English

This study evaluated antibacterial activity of Chrysanthemum cinerariaefolium (pyrethrum) flower dichloromethane crude extract, fractions and isolated compounds; pyrethrin II, jasmolin I and cinerolone against methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, Staphylococcus aureus and Shigella sonnei. The isolated compounds were obtained by carrying out column chromatography on dichloromethane extract and purifying the fractions using preparative High Perfomance Liquid Chromatography (HPLC). The structures of the isolated compounds were elucidated using 1D and 2D NMR. The bioactivity of crude extract, fractions and isolated compounds were determined using disc diffusion assay at a concentration of 100 mg/mL. The MIC and MBC were determined using microdilution method. The bioassay results showed that individually isolated compounds were not active on all the micro-organisms except Jasmolin I which showed slight activity on P. aeruginosa with 7.7&plusmn;0.6 mm. There was significant difference in the activity of the isolated compounds as a mixture and the activity of individual compounds on MRSA, S. aureus, P. aeruginosa, with P= 0.01, P= 0.0002, P= 0.0007 respectively (&alpha; =0.05, Tukey&rsquo;s test). Isolated compounds and isolated compounds as a mixture in a ratio of (1:1:1) were not active on S. sonnie. Those fractions and isolated compounds which caused inhibition zones of above 10 mm were subjected to MIC and MBC. The lowest MIC and MBC observed was for fraction 3 against MRSA which were 6.5 and 12.5 mg/mL respectively. The compound mixture had MIC and MBC of 25 and 50 mg/ml respectively against P. aeruginosa. Key words: MIC (minimum inhibitory concentration), MBC (minimum bacteriostatic concentration), bioassay, Chrysanthemum cinerariaefolium, Jasmolin, Pyrethrin II, Cinerolone.

Synthesis, the antiexudative and antimicrobial activity of 6-arylidene substituted imidazo[2,1-b]thiazoles

Aim. To expand the range of 6-arylidene-2-methyl-2,3-dihydroimidazo[2,1-b]thiazolones as potential objects for studying the antiexudative and antimicrobial activities. Results and discussion. It has been shown that the condensation of synthetically affordable 2-methyl-2,3-dihydroimidazo[2,1-b]thiazolone with aromatic aldehydes can be successfully used for obtaining the corresponding 6-ylidene-functionalized derivatives. The biological screening of the compounds synthesized revealed that they possessed a low or moderate anti-inflammatory activity and inhibited the inflammation process in the range from 3 to 44 %. During the study of the antimicrobial activity of the substances obtained it was determined that their minimum bacteriostatic and minimum fungistatic concentrations ranged from 31.25 to 250 μg/mL. Experimental part. The interaction of 2-methyl-2,3-dihydroimidazo[2,1-b]thiazolone with a series of benzaldehydes and salicylic aldehydes in refluxing acetic acid in the presence of anhydrous sodium acetate leads to new 6-arylidene-2-methyl-2,3-dihydroimidazo[2,1-b]thiazolones. The antiexudative activity screening was performed on the model of carrageenan-induced paw oedema of white outbred male rats. The antimicrobial activity of the compounds was studied using the microtechnique of two-fold serial dilutions in a liquid nutrient medium. Conclusions. It has been found that the Knoevenagel condensation of 2-methyl-2,3-dihydroimidazo[2,1-b]thiazolone with aromatic aldehydes is a convenient way for the structural modification of the position 6 of the heterocyclic system by the arylidene moiety. The arylidene derivatives obtained show a moderate antiexudative activity in the carrageenan-induced rat paw oedema assay, as well as the antimicrobial activity against some gram-positive and gram-negative bacteria and fungi.

Isolation and identification of the antibacterial compounds in Coptis chinensis for the preservation of wood

Wood is a biomass material that is easily eroded by wood-rotting fungi. Coptis chinensis is a natural green plant, which has an inhibitory effect on most microorganisms. Based on the highly toxic effects of the currently used wood chemical preservatives on humans, animals, and the environment, Coptis chinensis was selected to perform decay resistance experiments of wood in this paper. The active ingredients with bacteriostatic properties in Coptis chinensis were separated and screened via chemical treatment, and their structure was identified via nuclear magnetic resonance spectroscopy. The primary bacteriostatic components in Coptis chinensis were berberine hydrochloride, palmatine, and jatrorrhizine. The bacteriostatic zone experiment with a single component and different compounds for white-rot and brown-rot fungus were tested by the disc agar diffusion method. The bacteriostatic effect of berberine hydrochloride in a single active fraction was better. The three-fraction compound had the best bacteriostatic effect and was equivalent to alkaline copper quaternary. The natural active bacteriostatic fractions in Coptis chinensis had noticeable inhibitory effects on white-rot fungus (Trametes versicolor (L.) Lloyd) and brown-rot fungus (Gloeophyllum trabeum (Pers.) Murrill). The minimum bacteriostatic concentration was 0.01 g/mL. The results showed that Coptis extracts had potential as a wood protectant.

The investigation of antimicrobial and antifungal activity of some Artemisia L. species

Background: Throughout history pathogenic microorganisms cause infectious diseases. Medicinal herbs play an important role in human life because they are used for the therapy and production of herbal remedies. Therefore, it is relevant to study the antibacterial activity of medicinal herbs includingArtemisiaL. species.Aim: The purpose of this study was to investigate the antimicrobial and antifungal activity ofArtemisiaL. species extracts and to identify their synergistic antimicrobial effects with erythromycin against skin isolates ofStaphylococcus aureuswith different mechanisms of MLS-resistance.Materials and methods:Artemisia absinthiumL. herb extracts (AAs-4, AAs-7, AAs-9),Artemisia vulgarisL. herb extracts (AV-4, AV-7, AV-9) andArtemisia abrotanumL. herb extracts (AAr-4, AAr-7, AAr-9) were used in this study (solvents – 40%, 70% and 90% ethyl alcohol respectively).The determination of antimicrobial activity of extracts was performed using clinical isolates of antibiotic susceptible and antibiotic resistant microorganisms. Bacterial cultures were identified on the basis of the biochemical microtests “STAPHYtest 16”, “ENTEROtest 24”, “NEFERMENTtest 24” taking into account the complex of their morphological and cultural properties in accordance with the recommendations of the 9thedition of “Bergey’s Manual of Systematic Bacteriology”. Yeast-like fungi cultures were identified on the basis of 40 biochemical tests with the help of the VITEK 2 system using the VITEK 2 YST ID card.The synergism of the antimicrobial activity of extracts with erythromycin was investigated using the clinical isolate ofStaphylococcus aureuswith the non-inductive MLS-resistance mechanism (resistant to erythromycin at minimum bacteriostatic concentration of 125 μg/ml and minimum bactericidal concentration of 250 μg/ml without induction of resistance to clindamycin).Research results: The evaluation ofArtemisiaL. herb extracts activity was carried out using standard strains of microorganisms which are recommended by the WHO.The results of the conducted studies indicate thatArtemisiaL. herb extracts are able to reduce the growth of microorganisms. The investigated extracts showed the potent bacteriostatic action against the cocci or rod-shaped microflora. The antimicrobial activity ofArtemisiaL. herb extracts directly depends on the concentration of ethanol as the solvent.Artemisia vulgarisL. herb extracts (solvents – 70% and 90% ethanol) andArtemisia abrotanumL. herb extract (solvent – 90% ethanol) show synergism of antimicrobial activity with erythromycin in relation toStaphylococcus aureuswith efflux mechanism of MLS-resistance. The obtainedArtemisiaL. herb extracts can be used to create antifungal drugs, as well as antimicrobial drugs (against gram-positive and gram-negative bacteria).

Preparation of N, N-dialkyl quaternary ammonium chitosan and its long-lasting antibacterial finishing process for rabbit fur fabric

N,N-dialkylchitosan (N,N-CTS) was modified by n-butyraldehyde using Schiff base method, it is then synthesized with N,N-CTS by etherification with 3-chloro-2-hydroxypropyltriethylammonium chloride (CHPTAC-ethyl). FTIR and spectrophotometry were used to characterize their chemical structure and physical and chemical properties. The minimum antibacterial activity of the modified chitosan was determined by the minimum bacteriostatic method, and the minimum effective bacteriostatic concentration (MIC) of Escherichia coli was 0.2 g/L, which was better than that of natural chitosan. The antibacterial effect and washing resistance of rabbit wool fabric were investigated by using modified chitosan. After washing for 10 times, the results showed that the inhibition rate of N,N-CCTS on escherichia coli was still more than 99.9%.

Influence of antibiotics and silver nanoparticles on the change of sensitivity of &lt;i&gt;E. coli &lt;/i&gt;to antibacterial drugs

Research has been conducted to evaluate the effect of antibiotics and silver nanoparticles in combination with antibiotics on the change in antibiotic sensitivity to antibacterial drugs of E. coli ATCC 25922 reference strain and its isolate. Nanoparticles obtained by electron beam treatment of aqueous solution containing water-soluble stabilizing polymer and water-soluble silver salt were used in the experiment. During the treatment a beam of accelerated electrons obtained on the installation of a linear accelerator of the ILU-10 type passed through a solution with a working dose of 5–30 kGy ranging in size from 20 to 60 nm. Sensitivity of microorganisms of E. coli ATCC 25922 reference strain and its isolate obtained from cow endometritis to antibacterial substances and their combinations was determined from dilution with a minimum bacteriostatic concentration. The dilution in the amount of 0.2 ml was added to meat-and-peptone agar and the antibiotic sensitivity of microorganisms was determined by the disk diffusion method. Sensitivity to 24 types of antibacterial drugs was tested. Cultivation of E. coli ATCC 25922 with AgNPs in combination with one of the antibiotics (azitronite, amoxicillin, enroflox, ceftiofur, tylosin, cobactan, oxytetracycline) contributed to an increase in the number of drugs (from 14.3 to 57.1%), to which the microorganism was sensitive. Cultivation of the E. coli isolate with 5 (62.5%) of the studied antibiotics led to an increase in resistance from 1 (5.5%) to 3 (16.7%) antibacterial agents. AgNPs in combination with antibiotics azitronite, amoxicillin, enroflox, ceftiofur, tylosin, cobactan, gentamicin, oxytetracycline contributed to a decrease in the resistance of E. coli ATCC 25922 (from 15.4 to 46.1%) and E. coli field isolate (from 16.7 to 37.7%) to antibacterial drugs. The pronounced ability of AgNPs to increase antibiotic sensitivity was established. This was confirmed by the joint cultivation of antibiotics and AgNPs with E. coli ATCC 25922 and field isolate of E. coli, causing an increase in sensitivity and high sensitivity to antibacterial drugs, which was previously absent. The study confirmed the results of research on the ability of nanoparticles of metals of the transition group to affect the sensitivity of microorganisms to antibacterial agents and to restore it.

Investigation of the combined use effect of the antiseptic decamethoxin and fluoroquinolones on clinical strains S. aureus

Annotation. Postoperative infectious complications in eye microsurgery are most often caused by S. aureus strains, among which resistance to fluoroquinolones, first-line drugs for the prevention of postoperative complications, is common. An alternative to fluoroquinolones is antiseptics. The aim of the study was to investigate the effect of decamethoxin antiseptic on the antimicrobial properties of fluoroquinolones against S. aureus. Studies on the combined effect of the antimicrobial properties of fluoroquinolones and decamethoxin (DCM) were performed on the S. aureus museum strain ATCC 25923, on moderately stable and persistent S. aureus clinical strains (n=42) obtained from patients undergoing eye microsurgical procedures, by serial dilution method. The minimum bacteriostatic concentration (MBsC), the minimum bactericidal concentration (MBcC) of antimicrobials separately in pure form and with the addition of sub-bacteriostatic concentrations (subBsC, 1/4 MBsC) of DCM were determined. Statistical data processing was performed using special and office programs “STATISTICA 6.0”, “Microsoft Excel 2010”. The study found low sensitivity to fluoroquinolones in clinical strains of S. aureus, high sensitivity to DCM (MBsC 0.66±0.1; MBcC 3.19±0.4 μg/ml). The sensitivity of resistant and moderately resistant strains of S. aureus to fluoroquinolones in the presence of subBsC DCM was established: MBsC of ciprofloxacin in the presence of DCM decreased almost 4 times, norfloxacin — 5.5 times, ofloxacin — 6.8 times, of levofloxacin — 6.8 times, moxifloxacin 7.1 times. It was found that MBcC of norfloxacin for clinical resistant S. aureus strains decreased in 5.7 times, ofloxacin — in 9.2 times, levofloxacin — in 6.9 times, ciprofloxacin — in 8.6 times, moxifloxacin — in 7.9 times. The simultaneous use of antiseptic DCM and various fluoroquinolone chemotherapeutic agents provides effective protection against staphylococcal infection, contributes to the fight against antibiotic resistant strains of S. aureus.

Evaluation of Antimicrobial Efficacy of Ethanol Extracts of Fresh &lt;i&gt;Citrus sinensis&lt;/i&gt; (Sweet Orange) Seeds against Selected Bacterial Strains

The antibacterial activities of fresh Citrus sinensis seed oil and non-oil extract are investigated in this study. Gram positive (Staphylococcus aureus and Enterococcus faecalis) and Gram negative (Pseudomonas aeruginosa, Escherichia coli and Salmonella spp.) bacterial strains are used in this study and antibacterial activity is estimated using the agar well diffusion method. Zones of inhibition were measured and the minimum inhibitory concentration and minimum bacteriostatic concentrations were determined. The results show that the non-oil extract had better antibacterial activities against Staphylococcus aureus, Enterococcus faecalis and Escherichia coli compared to the oil extract (zones of inhibition at 200 μg/ml of 12 mm, 8 mm and 2 mm respectively for the nonoil extract; 4 mm, 6 mm, 0 mm respectively for the seed oil). The seed oil however had better antibacterial activity compared to the non-oil extract in Salmonella spp. (zones of inhibition at 200 μg/ml of 8 mm for the seed oil compared to 4 mm for the non-oil extract). Pseudomonas aeruginosa showed similar susceptibility to both extracts at both concentrations studied (zones of inhibition of 4 mm and 2 mm for both extracts at 200 μg/ml and 100 200 μg/ml respectively). Minimum inhibitory concentrations ranged from 50 – 100 μg/ml while minimum bacteriostatic concentrations ranged from 100 – 200 μg/ml. We conclude from our findings that both extracts hold promise in the development of antimicrobial therapeutics. &#x0D; Keywords: Citrus sinensis, Antibacterial, minimum inhibitory concentration, minimum bacteriostatic concentration

Antibacterial action of the essential oil from Cantinoa carpinifolia benth. Against Escherichia coli and Staphylococcus aureus strains

AbstractEssential oils have been increasingly studied as preservatives for the food industries because of their biological properties. However, there are few studies on the antibacterial potential of the essential oil of the species Cantinoa carpinifolia Benth. Thus, the aim of this study was to extract and chemically characterize the essential oil from Cantinoa carpinifolia Benth. and evaluate its antibacterial potential against strains of Escherichia coli and Staphylococcus aureus. The essential oil was extracted by hydrodistillation and analyzed by gas chromatography using mass spectrometer and flame ionization detectors. The antibacterial potential against Escherichia coli and Staphylococcus aureus was evaluated by macrodilution, through cell viability tests, membrane permeability tests and electronic microscopy (SEM). The essential oil is composed principally of the α‐ thujone e β‐ thujone monoterpenes, and the minimum bactericidal and bacteriostatic concentrations of the essential oil were 6.25 and 0.39 μL mL−1 for E coli and S aureus, respectively. Bacterial strains were completely inactivated after 135 minutes (E coli) and 200 minutes (S aureus), respectively. Intracellular biological activity was observed for the essential oil because the harmful effects on both species of bacteria could be observed in the electromicrographs.

Characteristics of the etiological structure and susceptibility to antibiotics, antiseptics of infectious pathogens of respiratory organs in children in critical states

The study of the etiological structure, the properties of pathogens of the respiratory infectious diseases in children and their resistance to antibacterial agents is particularly relevant in modern conditions, expands the search for new approaches to combating pathogens, improves the results of treatment and reduces the mortality of this pathology. The aim — study of etiological structure, sensitivity to antibiotics and antiseptics of pathogens of infectious and inflammatory diseases of respiratory organs in children. In the study there were enrolled 247 patients who were treated in Vinnytsia Regional Children’s Clinical Hospital (VRCCH) in 2016. The sensitivity of microorganisms to 23 antibacterial agents was determined by the disc-diffusion method according to the generally accepted method. The analysis of the antimicrobial activity of antiseptic drugs (decamethoxine, miramistin, chlorhexidine digluconate) was performed by a double serial dilution technique with the determination of the minimum inhibitory bacteriostatic (MIC) and bactericidal (MBcC) concentrations, by the method of successive serial dilutions of the drug in a liquid nutrient medium. In patients who were in inpatient treatment at the VRCCH in 2016 because of pneumonia there were found opportunistic microorganisms which were of etiological significance in the development of the infection. Among them there were Streptococci (47,3 %), Staphylococci (15,3 %), Candida (13,3 %), Enterococci (10,9 %), including a high proportion of owned non-fermenting gram negative bacilli (9,8%) and species of Enterobacteria (2,0 %). Isolated strains of microorganisms had moderate resistance to most modern antibiotic drugs. The sensitivity of isolated strains of microorganisms to reserved antibiotics as carbapenems, often being used in the treatment of critical states of patients in the intensive care units, was found to above 18,2%. The sensitivity to this antibiotic in Enterococcus spp. (7,1 %), Staphylococcus spp. (5,9 %) was also low. Carbapenems, fluoroquinolones (the 1st and 2nd generations), antibiotics and aminoglycosides were found to be effective against gram positive microorganisms in more then 45% of cases. According to this they were considered to be as drugs of choice in the treatment of infectious and purulent-inflammatory pathology of respiratory organs, caused metitcilin- and vancomycin-resistant strains of microorganisms. Resistance to these drugs among investigated strains did not exceed 9,0 %. The high bactericidal properties of antiseptics as decamethoxine was determined against S.pyogenes, Staphylococcus spp. Its MBcC against these bacteria (1,65±0,20 mkg/ml and 4,32±0,50 mkg/ml, respectively) proved the advantage of decamethoxine’s effectiveness in comparison with chlorhexidine digluconate 3,14 times, 2,44 times miramistin. Clinical strains of C.albicans showed the highest susceptibility to decamethoxine, which fungicidal activity was determined in the presence (16,17±2,33 mkg/ml), in comparison with chlorxedine (MFtsK 27,59±3,59 mg/ml) and miramistin activity (27,59±3,595 mkg/ml). In children with inflammatory diseases of the respiratory organs gram-positive cocci are among the predominant pathogens (73,5 %) of cases, in the association allocated – 8,0 % of pathogens. Allocated strains of microorganisms were moderately resistant to all antibiotics studied. For antimicrobial activity antiseptic drugs, especially decamethoxine, have advantages over antibiotics confirming the possibility of their use in combination with systemic antibacterials.