Wide Spectrum Of Antimicrobial Activity Research Articles

509. The Prevalence of Carbapenem-Resistant Enterobacteriaceae (CRE) in a Community Hospital Setting

BackgroundCarbapenems are bactericidal β-lactam antibiotics with a wide spectrum of antimicrobial activity. The emergence of carbapenem resistance, specifically carbapenem-resistant enterobacteriaceae (CRE), has left few viable treatment options. Multiple factors contribute to overutilization of carbapenems. At Union Hospital, in Terre Haute, Indiana, carbapenems are utilized for patients with a documented anaphylactic allergy to penicillins and cephalosporins and are the drug of choice for the treatment of ESBL infections. The overuse and inappropriate use of carbapenems plus increasing resistance has contributed to the development of CRE and other multi-drug-resistant organisms. Thus, an examination of resistance patterns was conducted at a smaller level in a community hospital.MethodsA retrospective analysis was conducted to examine carbapenem resistance patterns at Union Hospital. Patients with a CRE diagnosis from June 2017 to July 2018 were included. Data analysis examined baseline characteristics, culture site, presence of carbapenamase production, treatment agent, and patient outcome. An assessment of true infection vs. colonization was conducted for all positive CRE cultures.ResultsFifty-three patients were identified with a culture-proven CRE diagnosis. CRE was isolated from the following sites: urine, sputum, bronchial wash, blood, and tissue/wound culture. True infection was identified in 32 cases. For the 18 cases with likely colonization, urine was the most common site. Klebsiella pneumoniae was the most common organism identified with carbapenem-resistance. Fluoroquinolones, either alone or in combination with other agents, were the most commonly used agents to treat CRE infection. The average duration of targeted antibiotic therapy was 9 days. Mortality rates at 30 and 90 days were 10% and 14%, respectively.ConclusionThe prevalence of CRE infections is on the rise, and may be a result of increased broad-spectrum antibiotic use combined with inappropriate carbapenem use. Unconventional agents, such as fluoroquinolones, are being utilized to manage patients with documented CRE infection at Union Hospital.Disclosures All authors: No reported disclosures.

Developing freeze-dried bioproducts for the Russian military in the Arctic

The Arctic is currently a strategic region of Russia and it requires military protection. Good nutrition is a prerequisite for successful performance of the servicemen in such extreme conditions. The Russian armed forces do not have a special ration for the Arctic region. The existing rations lack products enriched with biologically ac- tive substances, probiotics, prebiotics, or vitamin and mineral complexes. Subcaloric nutrition, even with short-term physical exertion, in combination with low temperatures deprives the human body of vitamins and minerals. There- fore, the development of freeze-dried bioproducts with functional properties is highly relevant. This article presents the results of a study aimed to develop new freeze-dried milk-based bioproducts for the Russian military in the Arc- tic. For this, we created a microbial consortium of lactic acid bacteria with a wide spectrum of antimicrobial activity. We also used a range of functional ingredients, namely pectin, pine nut meal, a ‘Lactobel’ prebiotic protein-and-car- bohydrate product, rowan puree, and rosehip syrup in the amounts established during the study. The new freeze- dried milk-based bioproducts named ‘Pobeda’, enriched with combiotics and metabiotics, will provide the Russian military with better nutrition in the extreme conditions of the Arctic.

Effect of cationic, anionic and non-ionic polymeric surfactants on the stability, photo-catalytic and antimicrobial activities of yttrium oxide nanofluids

This work describes the utilization of combining the properties of yttrium oxide as a photoactive metal oxide and the properties of different kinds of charged surfactants: cationic, anionic and non-ionic polymeric types. The surface charge of surfactants was found to have a great influence on the stabilization performance of yttrium oxide particles in aqueous surfactant media, known as nanofluids, as well as on their photocatalytic and antimicrobial activities. Ionic surfactants (cetyltrimethylammonium bromide (CTAB) as a cationic surfactant and sodium dodecyl sulfate (SDS) as an anionic one) reduce the particle aggregation while the non-ionic polymeric surfactant (Polysorbate 80, Polyoxyethylene (20) sorbitan monooleate or (x)-sorbitan mono-9-octadecenoate poly(oxy-1,2-ethanediyl) (Tween 80)) enhanced the particles aggregation and formed a polymeric layer on the aggregates surface. The prepared nanofluids morphological structure and stability were studied by means of TEM, DLS and Zeta potential measurements. The prepared nanofluid systems were found to have an enhanced photo-catalytic performance for the degradation of MG dye studied under both UV and visible light irradiations and an enhanced wide spectrum antimicrobial activity against Gram positive and Gram negative bacteria as well as fungal stains.

Molecular identification of actinomycetes with antimicrobial, antioxidant and anticancer properties

The objectives of this study were to isolate and identify the actinomycetes strains from the soil and marine sediments and to evaluate the antimicrobial, antioxidant and cytotoxic activity of their bioactive secondary metabolites. Eight actinomycetes strains were isolated from soil and marine sediment samples collected from different areas in Egypt. Only three actinomycetes exhibited a wide spectrum of antimicrobial activities. They were active in vitro against microbial pathogen viz: Staphylococcus aureus, Escherichia coli, Salmonella typhi, Aspergillus parasiticus, Fusarium solani and Fusarium oxysporum. These promising isolates were selected and identified using molecular identification technique and identified as Streptomyces spp. The crude extracts from the three Streptomyces exhibited potent antimicrobial activities against a set of microbial pathogens as well as antioxidant and anticancer activity in human hepatocellular carcinoma cell line (HepG2). The crude extract of Streptomyces isolate D showed antitumor activity with lC50 0.85 µg/ mL. Forty compounds were identified from the two most promising ethyl acetate extracts of culture broth of Streptomyces sp. (D-EGY) by Gas Chromatography-Mass Spectrometry analysis. It could be concluded that the streptomycetes isolated from the Egyptian environment are promising candidates as antimicrobial, antioxidant and anticancer.

Halogenated boroxine dipotassium trioxohydroxytetrafluorotriborate K2[B3O3F4OH] inhibits emerging multidrug-resistant and β-lactamase-producing opportunistic pathogens

Halogenated boroxine dipotassium trioxohydroxytetrafluorotriborate, K2[B3O3F4OH] (boroxine) was previously shown to be very effective in inhibition of several carcinoma cell lines, including the skin cancer. Here, we investigated its antimicrobial potential by targeting the multidrug-resistant opportunistic pathogens associated with skin and wound infections. The antimicrobial testing against eleven bacterial and four fungal species revealed good activity of boroxine against pathogenic filamentous fungi Penicillium funiculosum and Aspergillus niger (MIC50 64 and 128 µg/ml), and a moderate bioactivity against the yeast Candida albicans (MIC50 512 µg/ml). Among the tested multidrug-resistant bacteria, the best antibacterial effect, stable over a 24-h period, was observed against the methicillin-resistant Staphylococcus aureus strain (MRSA) at MIC of 1024 µg/ml. The atomic force microscopy (AFM) used to investigate the morphology of S. aureus cells revealed indentations on its cell envelope after the boroxine exposure. These results show that in addition to the antitumor effect, boroxine exerts wide spectrum antimicrobial activity, thus may help preventing the development of skin and wound-related opportunistic infections.

ADSORPTION OF ACETIC ACID AND THE PROMOTERS OF FORMATION OF PEROXO GROUPS ON PLATINUM AT HIGH ANODIC POTENTIALS

Introduction. Peroxyacetic acid is a strong disinfectant with a wide spectrum of antimicrobial activity. The advantages of peroxyacetic acid are: no stable toxic derivates, the dependence on pH is unsignificant, efficiency and contact time are nondurable. Peroxyacetic acid is produced on an industrial scale by chemical synthesis. The output product requires specific storage conditions. Electrochemical methods of synthesis of peroxyacetic acid are divided into two directions: 1) production of РАА by the cathodic generation of hydrogen peroxide with the presence of acetic acid; 2) production peroxyacetic acid through the anodic oxidation. The advantages of electrochemical synthesis are production of peroxyacetic acid directly “in situ” and synthesis of diluted peroxyacetic acid and acetic acid. The problem of understanding and managing the process of peroxyacetic acid electrochemical synthesis poses the problem of obtaining new data on the component-solution adsorption in the region of high anodic potentials. The aim: to investigate the adsorption of acetic acid and promoters of the formation of peroxo groups on platinum at high anodic potentials. Research methods. The adsorption of acetic acid and peroxo group formation promoters was studied using the charging curves method on the surface of a Pt/PtO electrode. Results. It is shown that the potential shift to the electropositive region leads to a continuous increase in the adsorption of acetic acid along with an increase in the charge of the platinum surface. It is shown that when the electrode potential shifts to the electropositive region, the adsorption of Cl–, Br– and I– ions increases continuously with increasing platinum surface charge. It is shown that the dependence of the adsorption of CNS– ions on the potential has a maximum at ≈ 1.85 V. A further decrease in the adsorption of CNS– ions is associated with a stronger adsorption of their oxidation product – CN–. It has been established that, by the effect on the electrode surface, anions are placed in the CNS– > Cl– > Br– > I– series. Cl–, Br– and I– additives should be used for the electrochemical synthesis of peroxyacetic acid. They contribute to an increase in the current efficiency of the target product in comparison with the initial solution. CNS– additive is not effective. This is explained by the specific adsorption of CNS– ions on the surface of a platinum electrode.

The evaluation of the synergistic antimicrobial and antibiofilm activity of AamAP1-Lysine with conventional antibiotics against representative resistant strains of both Gram-positive and Gram-negative bacteria.

Background and purpose: Antimicrobial resistance toward antibiotics is reaching historical unprecedented levels. There is an urgent and imminent need to develop novel antimicrobial alternatives. Antimicrobial peptides could prove to be a successful group of antimicrobials for drug development. Recently, we have designed a novel synthetic peptide named AamAP1-Lysine. The peptide displayed potent wide-spectrum antimicrobial activities against Gram-positive and Gram-negative bacteria. The purpose of this study is to evaluate the antimicrobial effect of combining AamAP1-Lysine with five different conventional antibiotics each representing a distinct mechanism of action in order to explore the possibility of producing a synergistic mode of action against a resistant strain of Gram-positive and a resistant strain of Gram-negative bacteria.Methodology: The antimicrobial activity of AamAP1-Lysine in combination with five different antibiotics were evaluated for their antimicrobial activity employing standard antimicrobial assays, the synergistic activity of the peptide-antibiotic combinations were evaluated using checkerboard technique in addition to real-time time-kill assays. For the antibiofilm studies, the MBEC values were determined by employing the Calgary device.Results: The combination strategy displayed potent synergistic activities against planktonic bacteria in a significant number of peptide-antibiotic combinations. The synergistic activity managed to reduce the effective minimum inhibitory concentration (MIC) concentrations dramatically with some combinations exhibiting a 64-fold decrease in the effective MIC of AamAP1-Lysine individually. Additionally, the combined synergistic activities of the peptide antibiotics were evaluated, and our results have identified two peptide antibiotic combinations with potent synergistic activities against biofilm growing strains of resistant bacteria.Conclusion: Our results clearly indicate that peptide-antibiotic combinations could prove to be a very effective strategy in combatting multidrug-resistant bacteria and biofilm caused infections.

Advantages of the composition and actyvity of a new combined ointment with ethony for treatment of the wound process

An experimental study of a new combined ointment with ethony for treatment of wounds was carried out and its advantages were established compared with the similar drugs Inflarax (LLC FC "Health"), Levomekol (ZAO SPC "Borshchagovsky HFZ") and Oflokain-Darnitsa® (ZAO FF "Darnitsa"), having the same indications for use as a new ointment. The osmotic activity of ointment with ethony was studied by the method of kinetics of water absorption in in vitro experiments. The antimicrobial effect of ointment with ethony relative to standard and hospital strains of microorganisms by diffusion in agar in the modification of wells was determined: S. aureus ATCC 25923, E. coli ATCC 25922, P. aeruginosa ATCC 27853, B. subtilis ATCC 6633, P. vulgaris ATCC 4636, C. albicans ATCC 885/653, S. aureus 23, E. coli 15, P. aeruginosa 39, P. vulgaris 59, K. pneumoniae 6. The anti-inflammatory activity of ointment with ethony was established in a model of non-allergic contact dermatitis caused by turpentine. The results of experimental studies indicate the high efficiency of the proposed combined composition of the ointment with ethony due to the optimal combination of the components of the ointment base and active substances. It was established that the ointment with ethony showed a pronounced and prolonged osmotic activity, which contributes to the complete penetration and release of the active substances of the ointment in the tissue. An ointment with ethony revealed a wide spectrum of antimicrobial activity with respect to standard and hospital strains: with respect to C. albicans ATCC 885/653 and K. pneumoniae 6, this ointment was superior in activity to all comparison drugs. The ointment with ethony showed a pronounced anti-inflammatory effect, superior to the comparison drugs in effectiveness. Thus, due to the presence of a wide spectrum of pharmacological activity, ethony ointment can be recommended for the treatment of wounds with severe exudation in the first phase of the wound process, for wounds infected with mixed bacterial and fungal microflora, and for the prevention of their complications, as well as in complex therapy of the skin inflammatory processes.

Isolation and characterization of potential probiotic lactic acid bacteria isolated from cow milk and milk products

Probiotics refer to the living microorganisms that exhibit beneficial effect on the health of human by the intestinal microbial balance. Most widely used probiotics are lactic acid bacterial group found in milk and milk products. This study was aimed to characterize the probiotic properties of lactic acid bacterial (LAB) strains isolated from cheddar cheese, yoghurt and cow milk. Bacterial strains naturally grown in milk, cheddar cheese and yoghurt were isolated using De Mann Rogosa Sharpe (MRS) agar medium and incubated at 37oC for 48 h separately under aerobic and anaerobic conditions. There were eight strains grown under aerobic conditions and they were isolated, purified and characterization was done based on the morphological and biochemical analysis such as gram staining, catalase test and motility test. All the eight isolates were either rod or cocci shaped, gram positive, catalase negative, non-motile and non-spore formers. These eight isolated strains were identified as lactic acid bacteria. When screening of the 8 isolates was done to determine their antimicrobial activities against five human pathogenic strains such as E.coli, Klebsiella pneumoniae, Pseudomonas eaeruginosa, Salmonella sp and Staphylococcus aureus, three isolates (M6, C1 and Y1) showed wide spectrum antimicrobial activity. To determine the probiotic properties of these three isolates, different tests such as tolerance to acid, NaCl and bile, lactose utilization and antibiotic resistance were done. Though all the three isolates showed resistance to stomach pH (pH 3.0), the strain C1 showed significantly higher tolerance to stomach pH than the other strains. Though the three isolates grew well in the presence of NaCl and 0.3% bile, the isolate M6 showed significantly higher growth with NaCl and 0.3% bile than the others. Even though all the three isolates had the capacity of utilizing lactose, the isolate M6 showed prominent colour change in the lactose utilization test than the other two strains. When antibiotic susceptibility of the isolated LABs were evaluated using four antibiotics such as Ampicillin, Streptomycin, Bacitracin and Gentamycin, the strain M6 showed significantly higher resistance to Ampicillin and Bacitracin but sensitive to Streptomycin and Gentamycin. Other two isolates (C1 and Y1) were sensitive to all the four antibiotics used. Based on the antibiotic sensitivity tests and the analysis of probiotic properties, the isolated strain M6 was confirmed as a potential probiotic lactic acid bacterium. This strain was identified as Lactobacillus plantarum strain CIP 103151 through16S rDNA sequence analysis.

РЕЗУЛЬТАТЫ ИСПЫТАНИЙ БАКТЕРИЦИДНОЙ АКТИВНОСТИ НОВЫХ КОМПОЗИЦИОННЫХ ПРЕПАРАТОВ НА ПОПУЛЯЦИИ МИКРОБНЫХ КЛЕТОК E. COLI И S. AUREUS

The article presents the results of studies of the bactericidal activity of new composite preparations. Synergistic effect of the components of the drugs is established. The formulation of a new disinfectant Nika-Vetprofi with the maximum synergistic effect in respect of microbial cells of E. coli and S. aureus has been determined. The synergistic effect of the components of Nick-Vetprofi in samples 1 and 2 was established. The maximum synergistic effect against E. coli 1257 and S. aureus 209P. is achieved in combination of components of Nick-Vetprofi-2. Tests of the disinfectant effect of Nika-Vetprofi-2 in laboratory and production conditions have shown that the drug has a wide spectrum of anti-microbial activity and can be used as a disinfectant for veterinary use.

Zinc Oxide Spherical-Shaped Nanostructures: Investigation of Surface Reactivity and Interactions with Microbial and Mammalian Cells.

Two ZnO materials of spherical hierarchical morphologies, with hollow (ZnOHS) and solid cores (ZnOSS), were obtained through the hydrolysis of zinc acetylacetonate in 1,4-butanediol. The nature of the defects and surface reactivity for the two ZnO materials were investigated through photoluminescence, X-ray photoelectron spectroscopy, and electron paramagnetic resonance (EPR) spectroscopy proving the coexistence of shallow and deep defects and, also, the presence of polyol byproducts adsorbed on the outer layers of the ZnO samples. The EPR spectroscopy coupled with the spin-trapping technique showed that the surface of the ZnO samples generates reactive oxygen species (ROS) like hydroxyl (•OH) and singlet oxygen (1O2) as well as carbon-centered radicals. The ZnO materials exhibited a wide spectrum of antimicrobial activity, being active against Gram-positive, Gram-negative, and fungi strains, both in planktonic and, more importantly, adherent growth states. The decrease of antimicrobial efficiency in the presence of a ROS scavenger (mannitol) and the decrease of the cell viability with the ROS level suggest that one of the mechanisms that governs both the antimicrobial and cytotoxic activities on human liver cells is ROS-mediated. However, at active antimicrobial concentrations, the biocompatibility of the tested materials is very good.

Antimicrobial Activity of Selected Antimicrobial Peptides Against Planktonic Culture and Biofilm of Acinetobacter baumannii

Acinetobacter baumannii is one of the most challenging pathogens, on account of its predisposition to develop resistance leading to severe, difficult-to-treat infections. As these bacteria are more usually isolated from nosocomial infections, the new therapeutic options are demanded. Antimicrobial peptides (AMPs) are compounds likely to find application in the treatment of A. baumannii. These compounds exhibit a wide spectrum of antimicrobial activity and were found to be effective against biofilm. In this study, eight AMPs, namely aurein 1.2, CAMEL, citropin 1.1., LL-37, omiganan, r-omiganan, pexiganan, and temporin A, were tested for their antimicrobial activity. A reference strain of A. baumannii ATCC 19606 was used. Antimicrobial assays included determination of the minimum inhibitory concentration and the minimum biofilm eradication concentration. Considering the fact that the majority of A. baumannii infections are associated with mechanical ventilation and the use of indwelling devices, the activity against biofilm was assessed on both a polystyrene surface and tracheal tube fragments. In addition, cytotoxicity (HaCaT) was determined and in vitro selectivity index was calculated.

Chemical Composition, Antibacterial, and Antifungal activities of the Essential Oil of Thymus numidicus Poiret from Algeria

The present study has been carried on Numidian thyme (<i>Thymus numidicus<i/>), a medicinal plant belonging to the Lamiaceae family. Numidian thyme is an Algero-Tunisian endemic species. The essential oil was extracted from the leaves of the plant harvested in wild habitat at Tifrit (Tizi Ouzou, Algeria), by steam hydrodistillation with 1.58% yield. Analysis by GC–MS (Gas chromatography-mass spectrometry) of the essential oil helped to identify more than 70 compounds and to classify it as a thymol chemotype. The major components of the oil were: thymol (40.40%) and carvacrol (13.37%). Antibacterial and antifungal activities of <i>Thymus numidicus<i/> essential oil was studied in vitro on three bacterial (<i>Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa<i/>) and one fungal strains (<i>Candida albicans<i/>). The results showed that this essential oil has a wide spectrum of antimicrobial activity on Gram-negative and Gram-positive bacteria and possesses strong antifungal activity on Candida. This activity is probably due mainly to the predominant presence of thymol, and it is more important on fungi than bacteria. Results of this study look promising for the valuation of medicinal plants with the aim of promoting the Algerian pharmaceutical industry.

Preparation and properties of gum arabic cross-link binding nisin microparticles

Nisin is a small cationic peptide composed of 34 amino acid residues, it exhibits a wide spectrum antimicrobial activity against Gram-positive bacteria, but nisin has the disadvantages of poor stability and short duration of antibacterial activity. In order to improve the stability of nisin during food processing and storage period, the gum arabic (GA) is used to get GA-nisin microparticles. The analysis of zeta potential, SEM and FT-IR were used to characterize the combination of GA and nisin, test the antibacterial activity on Staphylococcus aureus and Escherichia coli, the bactericidal effect of GA-nisin microparticles decreased within 24 h compare to free nisin, however, GA-nisin microparticles after 121 °C treatment for 10 min, the activity loss rate is less than free nisin and has better sustained antibacterial effect at 25 °C. The results shown GA-nisin microparticles have better high-temperature stability and sustained bactericidal ability than the free nisin.

Recombinant overexpression of camel hepcidin cDNA in Pichia pastoris: purification and characterization of the polyHis-tagged peptide HepcD-His.

Hepcidin, a liver-expressed antimicrobial peptide, has been demonstrated to act as an iron regulatory hormone as well as to exert a wide spectrum of antimicrobial activity. The aim of this work was the expression, as secreted peptide, purification, and characterization of a new recombinant polyHis-tagged camel hepcidin (HepcD-His) in yeast Pichia pastoris. The use of this eukaryotic expression system, for the production of HepcD-His, having 6 histidine residues at its C terminus, was simpler and more efficient compared with the use of the prokaryotic system Escherichia coli. Indeed, a single purification step was required to isolate the soluble hepcidin with purity estimated more that 94% and a yield of 2.8 against 0.2 mg/L for the E coli system. Matrix-assisted laser desorption/ionization time-of-flight (TOF)/TOF mass spectrometry of the purified HepcD-His showed 2 major peaks at m/z 4524.64 and 4634.56 corresponding to camel hepcidin with 39 and 40 amino acids. Evaluation of disulfide bond connectivity with the Ellman method showed an absence of free thiol groups, testifying that the 8 cysteine residues in the peptide are displayed, forming 4 disulfide bridges. Circular dichroism spectroscopy showed that camel hepcidin structure was significantly modified at high temperature of 90°C and returns to its original structure when incubation temperature drops back to 20°C. Interestingly, this peptide showed also a greater bactericidal activity, at low concentration of 9.5μM, against E coli, than the synthetic analog DH3. Thus, the production, at a large scale, of the recombinant camel hepcidin, HepcD-His, may be helpful for future therapeutic applications including bacterial infection diseases.

Preparation and characterization of iron oxide magnetic nanoparticles functionalized by nisin.

Nisin is a known bacteriocin approved as a food additive for food preservation. It exhibits a wide spectrum antimicrobial activity against Gram-positive bacteria. Iron oxide magnetic nanoparticles were synthesized and characterized by X-ray diffraction method. A main part of iron oxide nanoparticles was found to be maghemite though a small quantity of magnetite could also be present. Magnetic nanoparticles were stabilized by citric, ascorbic, gallic or glucuronic acid coating. Stable iron oxide magnetic nanoparticles were functionalized by nisin using a simple and low cost adsorption method. Nisin loading was confirmed by FT-IR spectra, thermogravimetric analysis, dynamic light scattering and atomic force microscopy methods. Nisin-loaded iron oxide magnetic nanoparticles were stable at least six weeks as judged by the measurements of zeta-potential and hydrodynamic diameter. The antimicrobial activity of nisin-loaded iron oxide magnetic nanoparticles was demonstrated toward Gram-positive bacteria. Functionalized nanoparticles could therefore find the application as antimicrobials in innovative and emerging technologies based on the magnetic field.

Design, synthesis, structure elucidation and in vitro antiviral and antimicrobial evaluation

In this study, we described the synthesis of the derivatives of thiosemicarbazide, dicarboximide, 1,2,4-triazole-5-thione and 4-oxo-1,3-thiazolidine. Two different dicarboxylic acid anhydrides reacted with 4-substituted-3-thiosemicarbazide, and derivatives of thiosemicarbazide and dicarboximide were obtained. Next, cyclization reaction of dicarboximide derivatives in alkaline media was used to prepare 1,2,4-triazole-5-thione. The 4-oxo-1,3-thiazolidine was synthesized by the reaction of dicarboximide with ethyl bromoacetate. All obtained derivatives were analysed by 1H and 13C NMR spectra, and for one compound, the X-ray crystallography was done. Antimicrobial, antiviral and in vitro evaluations of cytotoxicity were examined. According to the preliminary antiviral screening, compounds 3 and 4 presented the antiviral activity against HSV-1 and CVB3. Additionally, compound 3 shows selective in vitro toxic effect against human epithelial cells FaDu, without affecting normal animal cell line (Vero). The same derivatives 3 and 4 also displayed a wide spectrum of antimicrobial activity against reference microorganisms and indicated both antibacterial and antifungal potential activities.

Overcoming Antimicrobial Resistance in Bacteria Using Bioactive Magnetic Nanoparticles and Pulsed Electromagnetic Fields.

Nisin is a known bacteriocin, which exhibits a wide spectrum of antimicrobial activity, while commonly being inefficient against Gram-negative bacteria. In this work, we present a proof of concept of novel antimicrobial methodology using targeted magnetic nisin-loaded nano-carriers [iron oxide nanoparticles (NPs) (11–13 nm) capped with citric, ascorbic, and gallic acids], which are activated by high pulsed electric and electromagnetic fields allowing to overcome the nisin-resistance of bacteria. As a cell model the Gram-positive bacteria Bacillus subtilis and Gram-negative Escherichia coli were used. We have applied 10 and 30 kV cm-1 electric field pulses (100 μs × 8) separately and in combination with two pulsed magnetic field protocols: (1) high dB/dt 3.3 T × 50 and (2) 10 mT, 100 kHz, 2 min protocol to induce additional permeabilization and local magnetic hyperthermia. We have shown that the high dB/dt pulsed magnetic fields increase the antimicrobial efficiency of nisin NPs similar to electroporation or magnetic hyperthermia methods and a synergistic treatment is also possible. The results of our work are promising for the development of new methods for treatment of the drug-resistant foodborne pathogens to minimize the risks of invasive infections.

Bioactivities of Traditional Medicinal Plants in Alexandria.

In traditional folklore, medicinal herbs play a vital role in the prevention and treatment of microbial diseases. In the present study, the phenolic profiles of the medicinal plants Asparagus aethiopicus L., Citrullus colocynthis L., Senna alexandrina L., Kalanchoe delagoensis L., Gasteria pillansii L., Cymbopogon citratus, Brassica juncea, and Curcuma longa L. were determined by high-performance liquid chromatography with a diode-array detector method. The results revealed rich sources of important compounds such as robinin in the fruits and leaves of A. aethiopicus; caffeic acid in the tubers of A. aethiopicus and quercitrin in the leaves of G. pillansii. Further, relatively high antioxidant, antibacterial, and antifungal activities were observed in C. colocynthis fruit coat, S. alexandrina pods, and A. aethiopicus leaves, respectively. The relatively higher the bioactivities of plants extracts associated with the phenols in these plants, in particular, the more abundant the phenols. Therefore, it was concluded that the fruit coat of C. colocynthis, pods of S. alexandrina, and leaves of A. aethiopicus might be excellent sources of natural products. These plant extracts also have a wide spectrum of antimicrobial activities that could be used in the pharmaceutical industries and to control diseases.

Antimicrobial efficacy of Syzygium antisepticum plant extract against Staphylococcus aureus and methicillin-resistant S. aureus and its application potential with cooked chicken

For the past decades, there has been a growing demand for natural antimicrobials in the food industry. Plant extracts have attracted strong research interests due to their wide-spectrum antimicrobial activities, but only a limited number have been investigated thoroughly. The present study aimed at identifying a novel anti-staphylococcal plant extract, to validate its activity in a food model, and to investigate on its composition and antimicrobial mechanism. Four plant extracts were evaluated against Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) in vitro, with Syzygium antisepticum leaf extract showing the strongest antimicrobial activity (MIC = 0.125 mg/mL). Relatively high total phenolic content (276.3 mg GAE/g extract) and antioxidant activities (90.2–138.0 mg TE/g extract) were measured in S. antisepticum extract. Food validation study revealed that higher extract concentration (32 mg/mL) was able to inhibit or reduce staphylococcal growth in cooked chicken, but caused color change on meat surface. By GC-MS, β-caryophyllene (12.76 area%) was identified as the dominant volatile compound in extract. Both crude extract and pure β-caryophyllene induced membrane damages in S. aureus. These results suggested good anti-staphylococcal properties of S. antisepticum plant extract, identified its major volatile composition and its membrane-damaging antimicrobial mechanism.