Optimal Antibacterial Activity Research Articles

Finafloxacin, a Novel Fluoroquinolone, Reduces the Clinical Signs of Infection and Pathology in a Mouse Model of Q Fever.

Finafloxacin is a novel fluoroquinolone with optimal antibacterial activity in low pH environments, therefore offering a therapeutic advantage over some traditional antibiotics, in treating bacterial infections associated with acidic foci. Coxiella burnetii, the causative agent of Q fever, is a bacterium which resides and replicates in acidic intracellular parasitic vacuoles. The efficacy of finafloxacin was evaluated in vivo using the A/J mouse model of inhalational Q fever and was compared to doxycycline, the standard treatment for this infection and ciprofloxacin, a comparator fluoroquinolone. Finafloxacin reduced the severity of the clinical signs of infection and weight loss associated with Q fever, but did not reduce the level of bacterial colonization in tissues compared to doxycycline or ciprofloxacin. However, histopathological analysis suggested that treatment with finafloxacin reduced tissue damage associated with C. burnetii infection. In addition, we report for the first time, the use of viable counts on axenic media to evaluate antibiotic efficacy in vivo.

Biological activity of green synthesized silver nanoparticles and different plant extracts of Solanum khasianum Clarke

Solanum khasianum Clarke. (Solanaceae), an important medicinal plant used to treat several diseases. Leaf, root, fruit and bark extracts of S. khasianum and the green synthesized silver nanoparticles were assayed for its antibacterial activity against gram positive and gram negative bacteria, using agar well diffusion method. Among all the solvent extracts tested, methanolic extracts were found to possess elevated activity. The optimal antibacterial activity is exhibited by silver nanoparticles against Pseudomonas flourescens with a maximal zone of inhibition (22mm). In the present study, the efficacy of green synthesized silver nanoparticles over the different plant extracts of S. khasianum against different bacterial strains was reported. This investigation discloses the potentiality of using silver nanoparticles as an antibacterial agent.

The effect of hydrolysis duration on the antibacterial activity of swamp eel head protein hydrolysate produced by papain against histamine-producing bacteria

Swamp eel (Monopterus albus) processing produced byproducts such as heads that possess a high protein, carbohydrate, lipid, and energies content. Swamp eel heads were hydrolyzed (SEHPH) and tested for their antibacterial activity against histamine-producing bacteria (HPB) to explore the potency. The hydrolysis was conducted by a commercial papain enzyme PAYA (concentration 4%) with various hydrolysis times (0, 60, 120, and 180 minutes) at 60o C with pH 5. The results indicated that increasing hydrolysis time increased solubility and the degree of hydrolysis. The inhibitor concentration 50 test using microdilution of SEHPH inhibited 50% against three HPB named Citrobacter sp. (CK1), Klebsiella sp. (CK13), and Morganella morganii (TK7) at 20 mg/ml. The optimum antibacterial activity test by disk diffusion method was formed by each minute of hydrolysis with the best inhibition zone to Klebsiella sp. (CK13). The macrodillution method showed the highest inhibition was produced by 180 hydrolyses with 45% on CK1, 54% on CK13, and 48% on TK7. These results indicated that SEHPH has potency as an antibacterial agent to reduce histamine-producing bacteria.

Development of Antibacterial Fabrics by CuO Doped TiO2 Composites

The study aimed to get the optimum antibacterial properties on fabric. CuO-doped TiO2 composite was synthesized by photo assisted deposition method. The amount of CuO loading varied (1.5%, 3% and 6%) in the total weight of composite to obtain the optimum effect of CuO in photodisinfection Escherichia coli. The 3% CuO/TiO2 possessed the optimum antibacterial activity with 92% of E. coli were disinfected within 2 h. This phenomenon was supported by the UV-Vis DRS results, which implied the addition of CuO could act as a dopant and an electron trapper in reducing the band-gap energy to 2.97 eV in 3% CuO/TiO2. Fourier-transform infrared spectroscopy (FTIR) analysis showed the Ti-O-Ti and Ti-O-Si bands, which confirmed TiO2 attach on fabric.

Gum Acacia Modified Ni Doped CuO Nanoparticles: An Excellent Antibacterial Material

Ni doped CuO Nps (Ni0.1CuO-GA) grown in gum acacia (GA) medium behaved as an efficient antibacterial material. The antibacterial activity of Ni0.1CuO-GA was much higher than the control antibiotic (Amplicillin) and simple Ni doped CuO Nps. Different concentrations of GA were used (as the growth medium) to tune the material’s bioactivity. Among the synthesized Ni0.1CuO-GA samples (G1–G4), G3 sample (synthesized using 1.5% (w/v) GA) showed optimum antibacterial activity. The corresponding undoped sample (CuO-GA) was less active. The structural, morphological, compositional and optical properties of G3 have been determined by FTIR, XRD, FESEM, HR-TEM and UV–visible analyses. It exhibited excellent antibacterial activity for Enterobacter, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus bacterial strains (ZOI being 27 mm, 28.75 mm, 27.50 mm and 26.50 mm respectively). ZOI for the reference antibiotic for respective bacterial strains were 17.50 mm, 18.50 mm, 18.25 mm and 19.50 mm respectively, while ZOI for neat CuO Nps, G1, G2, G4 and CuO-GA samples ranged between 21 and 24 mm for the same doses. The advantage Ni doping combined with the usage of GA as growth medium is evident by the excellent antibacterial behaviour of G3.

Microbiological and cytotoxic perspectives of active PCL/ZnO film for food packaging

Nanoparticles of zinc oxide (ZnO) were added to poly(ε-caprolactone) (PCL), and PCL/ZnO casting films were produced, afterwards films were characterized using Fourier Transform Infrared Spectroscopy (FTIR), x-ray Diffraction (XRD), Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). Additionally, antimicrobial and cytotoxic parameters were determined using microbial adhesion testing according to JIS Z 2801: 2000 (E) and agar diffusion method according to ISO 10993-5 , respectively. From collected data, the chemical identity of individual components was kept and the surface control could be achieved changing the composition. According to FTIR spectra and using the Lambert-Beer law higher interaction ratios were met for higher ZnO content which is linked to antimicrobial action. As revealed by AFM analysis, at 5% of ZnO, nanoparticles were well dispersed in PCL matrix with uniform surface film. Analyses from antibacterial activity and cytotoxicity suggested pathogenic Staphylococcus aureus growth was hindered in ZnO films; specifically for PCL/ZnO 5% optimal antibacterial activity and toxicity absent were reached. Summing up, PCL/ZnO5% nanocomposites films offer great potential for commercial applications as active food packaging.

SYNTHESIS AND UTILITY OF NEW POLYCYCLIC COMPOUNDS AS POTENTIAL ANTIMICROBIALS BASED ON CHROMENE MOIETY

Objective: The present research aims to synthesize some new polycyclic compounds including chromene moiety and study their antimicrobial activity.
 Methods: Several new polycyclic systems including chromene scaffold incorporated with pyridine, pyrimidine, imidazopyrimidine, and imidazodiazocine were achieved via condensation reaction of chromene derivative under the proper condition with various reagents namely; cyanothioacetamide, phenyl isothiocyanate, malononitrile, carbon disulfide, benzaldehyde, triethylorthoformate, and 1,4-dichlorobutane. Moreover, a chlorodiazenyl chromene derivative was reacted with some substances possessing active–CH2-bridge such as ethyl cyanoacetate and malononitrile to end up with hydrazono compounds. Such compounds were eventually cyclized with hydrazine hydrate to form pyrazole and oxopyrazole derivatives. Moreover, compound 1 was treated with benzoyl acetone, and then followed by cyclization with malononitrile to provide the corresponding 2-amino14-(4-methoxyphenyl)-4-methy-5-phenyl-14H-benzo[5,6] chromeno[2,3H][1,6]naphthyridine-3-carbonitrile (20).
 Results: The results of the antimicrobial screening in vitro revealed that the inhibition zone (mm) of the synthesized compounds 1-3, 5 and 8 implied their optimum antibacterial activity, while the compounds 4, 6 and 9-13, 15 showed a moderate to weak antibacterial activity against multiple species of B. subtilis, S. aureus, E. coli and P. aeruginosa. In contrast, the compounds 1, 6, 11, 15 showed high antifungal activities against different species of A. flavinand C. albicans, while the other compounds exhibit a moderate to poor antifungal activity.
 Conclusion: It is remarkable that a series of chromene derivatives synthesized by a simple and available method leads to a molecule of promising antimicrobial activity. Further research is recommended to approve the importance of polycyclic systems for various applications.

Optimized Synthesis of Magnesium Oxide Nanoparticles as Bactericidal Agents

Increased antibiotic resistance of microorganisms as well as the need to reduce health-care costs necessitates the production of new antimicrobials at lower costs. For this reason, this study was aimed to optimize the synthesis of magnesium oxide nanoparticles with the greatest antibacterial activity. In this study, 9 experiments containing different proportions of the factors (magnesium nitrate, NaOH, and stirring time) effective in the synthesis of magnesium oxide nanoparticles were designed using the Taguchi method. Magnesium oxide nanoparticles were synthesized using the coprecipitation method, and their antibacterial activity was evaluated using colony-forming unit (CFU) and disk diffusion. Morphology, crystalline structure, and size of synthesized nanoparticles were investigated using Fourier transform infrared (FTIR), X-ray diffraction (XRD), and scanning electron microscope (SEM). The optimum conditions (0.2 M magnesium nitrate, 2 M NaOH, and 90 min stirring time) for the synthesis of magnesium oxide nanoparticles with the greatest antibacterial activity were determined using the Taguchi method. The results of colony-forming unit and disk diffusion revealed the optimal antibacterial activity of synthesized nanoparticles against Staphylococcus aureus and Escherichia coli bacteria. The results obtained from FTIR and XRD analyses confirmed the synthesis of nanoparticles with favorable conditions. Also, according to the SEM image, the average size of synthesized nanoparticles was determined to be about 21 nm. According to the results, magnesium oxide nanoparticles can significantly reduce the number of Gram-positive and Gram-negative bacteria and can be used as an appropriate alternative to commonly used antibacterial compounds in order to tackle drug resistance among pathogens.

Third Order Non-linear Optical Susceptibility (χ(3)) and Evaluation of Antibacterial Activity of Cu-Doped ZnSe Nanocrystals Fabricated by Hydro-Microwave Technique

In this work, Cu-doped ZnSe nanoparticles (NPs) at the presence of different Cu contents and also with/without 6 min microwave irradiation were fabricated in aqueous medium, and then some optical properties and also their antibacterial properties against two gram-positive bacteria of Staphylococcus aureus and Bacillus cereus were investigated, employing disc-diffusion method. To fabricate these NPs, Se ion source was provided from the interaction between Se and NaBH4, and zinc acetate was used as Zn ion source. At the fixed pH of 11.2, thioglycolic acid was used as surfactant to prevent agglomeration of NPs. Previously reported results of X-ray diffraction characterization and UV-visible spectroscopy of solutions containing nanoparticles, show the range of 1.94–2.14 for particles size and 3.50–3.65 eV for energy gap. In this research, non-linear optical susceptibility of ZnSe and ZnSe:Cu nanoparticles have been determined; results imply that these nanoparticles have a high potential in optical and optoelectronic applications and among them, sample owing 1.5% of impurity and so owing the highest χ(3), is an optimum candidate in optical applications. Results of the present research confirm that nonlinear optical susceptibility is in inverse relation with the energy gap and increase with increasing of Cu%. To explore the antibacterial activity of the present samples, first Staphylococcus aureus and Bacillus cereus bacteria were inoculated on Muller–Hinton–Agar culture, and then the loaded discs by nanoparticles were placed on them. After 18 h from the incubation, the inhibition zone diameters (their antibacterial sensitivity) were measured for each bacteria. Results of this research imply on that these nanoparticles have considerable antibacterial activity against the gram-positive bacteria of Staphylococcus aureus and Bacillus cereus, and have the usage ability in the field of antibacterial drugs. During this assessment, increase in impurity content resulted in improvement of antibacterial potential, especially the more efficiency on Staphylococcus aureus. In addition, it was shown that increase of the concentration (loading volume of solution containing NPs) lead to increase of bacterial growth inhibition. Results confirm that the optimal antibacterial activity is devoted to the 0.75% Cu-doped nanoparticles on Staphylococcus aureus. Also the undoped sample prepared under 6 min microwave irradiation had the highest antibacterial activity against the Bacillus cereus. In brief, studied NPs show excellent bactericidal and optical activity, introducing them as promising bio-opto-materials.

English

This study aimed at isolating and characterizing antibiotic producing actinomycetes from a specific geographic location Alba’qa, Jordan, with a known soil character, and study the effect of the environmental factors on their antimicrobial activity, in order to relate the actinomycetes flora to the environmental characteristics. Soils of the Alba’qa region are of uniform composition and contain antimicrobial producing microorganisms. Although the initial aim was to isolate organisms of the genera Actinomyces, other organisms such as Aspergillus and other antibiotic producing microorganisms “mostly bacteria” were also isolated. Actinomycetes showed antimicrobial effect on all tested bacteria “Escherichia coli SQ21, Staphylococcus aureus SQ31, Streptococcus pyogenes SQ33, Serratia marcescens SQ22, Staphyloccocus epidermidis SQ32  and Bacillus spp. SQ41” depending on the media they were cultured on and the temperature they were incubated at. It was established that the optimum antibacterial activity is shown when cultivated on GYE medium at 30°C. This made a beneficial first step to find treatments for the diseases caused by the pathogenic bacteria.   Key words: Actinomycetes, antibiotics, environmental factors, soil.

Enhancement of strength and durability of fly ash concrete in seawater environments: Synergistic effect of nanoparticles

Fly ash is used in concrete industry to reduce the amount of cement and to enhance the durability of concrete. Nuclear industry recently adopted fly ash concrete as a government initiative to reduce carbon footprint and also to provide an impermeable skin for the several structures in the cooling water system exposed to marine environment for enhanced durability. Earlier detailed studies on fly ash concrete has shown that despite its superiority over conventional concrete with respect to strength and durability, some concerns such as delayed setting and hydration, low early-age strength, and higher carbonation may pose a problem for its wider application. The present work is an attempt to overcome these deficiencies by nanophase modification of concrete with the incorporation of nano-titania and nano-calcium carbonate at 2% by weight of cement. Four different types of concrete mix were arrived and specimens of different sizes were cast in order to explore the various properties of concrete. After 28 days of curing in potable water, the samples were exposed to seawater at Nuclear Desalination Demonstration Plant (NDDP) sump at Kalpakkam and were withdrawn for testing at different ages like 56, 90, 180 and 365 days. Nanophase modification increased the pozzolanic activity resulting in faster hydration, early-age strength and long-term compressive and split tensile strength, permissible electrical resistivity for corrosion, lower chloride ion penetration, carbonation depth biofilm formation and higher internal pH. Among the different mixes, the synergy of 1% NC and 1% NT emerged superior with excellent concrete properties related to mechanical properties, pore structure, durability and optimum antibacterial activity.

Combination types between graphene oxide and substrate affect the antibacterial activity

Duo to their superior physicochemical properties, graphene and its derivatives (GDs), such as graphene oxide (GO) and reduced graphene oxide (rGO), have attracted extensive research interests around the world. In recent years, antibacterial activities of GDs have aroused wide concern and substantial works have been done. However, the underlying antibacterial mechanisms still remain controversial. Antibacterial activities of GDs vary with various factors, such as size, number of layers, oxygen-containing groups, and experimental surroundings. We assume that combination types between graphene oxide and substrate may affect the antibacterial activity. Therefore, in this work, GO was fixed on the titanium surface with three kinds of combination types including drop with gravitational effects (GO-D), electrostatic interaction (GO-APS) and electrophoretic deposition (GO-EPD), and the antibacterial activities in vitro were systematically investigated. Results showed that combination types affected the ability of GO for preventing Staphylococcus aureus (S. aureus) from gathering, sharpness of wrinkles or edges and reactive oxygen spices (ROS) levels. Once S. aureus are in the form of separation without aggregation, GO can effectively interact with them and kill them with sharp wrinkles or edges and high ROS levels. GO-EPD could effectively prevent S. aureus from gathering, own sharp wrinkles or edges and could generate higher ROS levels. As a result, GO-EPD exhibited optimal antibacterial activity against S. aureus, followed by GO-APS and GO-D.

Short Proline-Rich Lipopeptide Potentiates Minocycline and Rifampin against Multidrug- and Extensively Drug-Resistant Pseudomonas aeruginosa.

A series of 16 short proline-rich lipopeptides (SPRLPs) were constructed to mimic longer naturally existing proline-rich antimicrobial peptides. Antibacterial assessment revealed that lipopeptides containing hexadecanoic acid (C16) possess optimal antibacterial activity relative to others with shorter lipid components. SPRLPs were further evaluated for their potential to serve as adjuvants in combination with existing antibiotics to enhance antibacterial activity against drug-resistant Pseudomonas aeruginosa Out of 16 prepared SPRLPs, C12-PRP was found to significantly potentiate the antibiotics minocycline and rifampin against multidrug- and extensively drug-resistant (MDR/XDR) P. aeruginosa clinical isolates. This nonhemolytic C12-PRP is comprised of the heptapeptide sequence PRPRPRP-NH2 acylated to dodecanoic acid (C12) at the N terminus. The adjuvant potency of C12-PRP was apparent by its ability to reduce the MIC of minocycline and rifampin below their interpretative susceptibility breakpoints against MDR/XDR P. aeruginosa An attempt to optimize C12-PRP through peptidomimetic modification was performed by replacing all l- to d-amino acids. C12-PRP demonstrated that it was amenable to optimization, since synergism with minocycline and rifampin were retained. Moreover, C12-PRP displayed no cytotoxicity against human liver carcinoma HepG2 and human embryonic kidney HEK-293 cell lines. Thus, the SPRLP C12-PRP is a lead adjuvant candidate that warrants further optimization. The discovery of agents that are able to resuscitate the activity of existing antibiotics against drug-resistant Gram-negative pathogens, especially P. aeruginosa, is of great clinical interest.

Development of Anti Acne Cream (w/o/w Multiple Emulsion) Containing Green Tea Leaf Waste

Background: To date, green tea leaf waste is not well utilized, the waste is remain considered as a waste. Previous studies found that green tea leaf waste still have a fairly high EGCG content. EGCG has benefits as an antibacterial. Utilization of green tea leaf waste started from formulation until the diversification of multiple emulsion w/o/w products has not been reported.Objective: To develop anti acne cream (W/O/W) multiple emulsion containing green tea leaf waste and evaluate its antibacterial activity against acne-inducing bacteria of Propionibacterium acnes (P.acnes).Methods: Phase one of this research was green tea leaves was extracted by infundation and fractionation method using ethyl acetate and prepared in different concentration (1% to 6%). The second stage was ethyl acetate fraction of green tea leaf extract was tested for its antibacterial activity against P.acnes. Third stage was tested physical properties of formulation with w/o/w multiple emulsion.Results: The optimal antibacterial activity of ethyl acetate fraction of green tea leaf extract against P.acne was at the concentration of 6%, with inhibition zone of 32.6 mm ±0.57. The formula of w/o/w multiple emulsion loaded with green tea leaves waste of 6% active substance demonstrated a good physical properties which can spread 90.4 cm2 ± 0.03, pH 5.00 ± 0.02 and microscopic analysis showed multiple emulsion w/o/w.Conclusion: The concentration of 6% green tea leaf waste formulated in multiple emulsion had a good physical and antibacterial activity for a referred standard. It is necessary to test the stability of multiple emulsion formula.

Synthesis of Anti-Acne Ointment of Ethanol Extract of White Plumeria Leaves (Plumeria Alba L.)

Acne is a chronic inflammatory skin disease pilosebaceous follicle, where the oil- producing glands are clogged and contaminated by bacteria. Propionibacterium acne is one of the bacteria that contributes to the pathogenesis of acne. Acne treatment was done by reducing the population of bacteria using an antibacterial. One of the plants that have antibacterial activity is white plumeria. The ethanol extract of white plumeria leaves contains antibacterial secondary metabolites, which are alkaloids and saponins. The aim of this study is to formulate white plumeria leaves extract into the water leached ointment base. Characteristics of the ointment were determined by evaluating the stability of the ointment including organoleptic, adhesion test, dispersive power test, determination of pH, and the antibacterial activity test. The results showed that the ointment of ethanol extract of white plumeria leaves has some characteristics, semisolid form, white, has distinctive smell of ointment, homogeneous but not protective, has a pH of 4.57 - 6.10, dispersive power of 5.10 - 6.06 cm, the adhesiveness of 1.67 - 3 seconds, and optimum antibacterial activity at concentrations of 5 ppm providing inhibition zone of 24.00 mm.

Synthesis, physicochemical, and biological activities of novel N-acyl tyrosine monomeric and Gemini surfactants in single and SDS/CTAB-mixed micellar system

A series of single-chained N-acyl tyrosine surfactants with varying chain lengths (C10-C18) and degree of unsaturation, as well as an N-acyl Gemini tyrosine surfactant with chain length C12, were synthesized, and the structures were confirmed using spectral analysis. The effect of chain length and level of unsaturation on the physicochemical and antibacterial properties of the N-acyl tyrosine surfactants was evaluated. The C12 derivative displayed the optimum antibacterial activity among the single chain surfactants, and the presence of double bond in the oleoyl derivative enhanced the antibacterial activity over its saturated analogue. The N-acyl Gemini surfactant displayed the highest antibacterial activity among the series and also showed greater micelle forming ability than its single chain analogue. Mixed micellar behavior of the N-acyl Gemini surfactant with conventional cationic (CTAB) and anionic (SDS) surfactants in aqueous solution was studied. The negative value of the interaction parameter β12 observed for the N-acyl Gemini in binary mixture with CTAB surfactant indicated a synergistic interaction within the mixed micellar system. However, the binary mixture with SDS displayed antagonistic behavior. The binary mixture of N-acyl Gemini surfactant with CTAB displayed better antibacterial activity and foaming properties than with SDS mixtures. Optimum antibacterial activity was observed for N-acyl Gemini surfactant with mole ratio 0.4 to 0.6 in the CTAB binary mixture, at which the lowest ocular irritation index was observed. Overall, the study showed that the Gemini surfactant in combination with the conventional surfactant CTAB can be used as potential ingredients in detergent and pharmaceutical formulations.

A high-dose aminoglycoside regimen combined with renal replacement therapy for the treatment of MDR pathogens: a proof-of-concept study.

Infections caused by MDR Gram-negative (GN) organisms in critically ill patients are a therapeutic challenge. The administration of high-dose aminoglycoside (HDA) therapy coupled with high-flow continuous veno-venous haemodiafiltration (CVVHDF) could allow required high drug peaks to be achieved with acceptable drug elimination. All adult patients present on the ICU between October 2009 and July 2014 who had MDR GN sepsis were considered for HDA and high-flow (>45 mL/kg/h) CVVHDF when an isolated pathogen was susceptible or had intermediate susceptibility to aminoglycosides and the patient's condition was not improving with conventional therapy. Optimal antibacterial activity was defined as a peak concentration of at least eight times the MIC. Fifteen patients infected with MDR GN pathogens (11 with Pseudomonas aeruginosa; 10 with abdominal infections and 5 with respiratory infections) were treated with amikacin (n = 11), gentamicin (n = 3) or tobramycin (n = 1) and high-flow CVVHDF. A favourable clinical response was observed in eight (53%) patients, including three in whom microbial eradication was obtained. Six patients were discharged alive from the ICU, and five from the hospital. No renal toxicity was observed among survivors. In this cohort of septic patients with MDR GN infections, HDA combined with high-flow CVVHDF represented a valuable therapeutic option. The effectiveness of this approach should be further evaluated in larger studies.

Detection and qualification of optimum antibacterial and cytotoxic activities of silver‐doped bioactive glasses

This study aims to detect the optimum antibacterial activity of silver-doped bioactive glasses (Ag-BGs) for prevention of post-transplant infections in tissue engineering. The results have shown that the Ag-BG samples had broad-spectrum antibacterial efficacy in an Ag concentration-dependent manner. The 2% Ag-BG had the highest effect during the first 10 min to 72 h. The minimum inhibitory concentration of 2% Ag-BG was estimated to be 2 mg/ml for Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) and 2.66 mg/ml for Staphylococcus aureus (S. aureus). A concentration of 0.5% Ag-BG repressed growth of E. coli after 1 h, but did not have any detectable antibacterial effect for longer periods. Evaluation of the effects of prepared Ag-BG on human osteoblast cells viability showed that 1 and 2% samples changed the cell proliferation rate in masses of more than 3.33 and 2 mg/ml, respectively. Moreover, in a typical manner, the release of Ag ions from the glass structure started immediately, continued steadily and affected bacterial growth when it reached its critical concentration in the medium. This systematic study can illustrate the optimum antibacterial property of the Ag-BG samples in masses of 3.33 and 2 mg/ml for 1 and 2% Ag, respectively, for prevention of post-transplant infections.

Structure activity relationship of substituted 1,5-naphthyridine analogs of oxabicyclooctane-linked novel bacterial topoisomerase inhibitors as broad-spectrum antibacterial agents (Part-4).

Bacterial resistance is rapidly growing, necessitating the need to discover new agents. Novel bacterial topoisomerase inhibitors (NBTIs) are new class of broad-spectrum antibacterial agents targeting bacterial DNA gyrase and topoisomerase IV. This class of inhibitors binds to an alternative binding site relative to fluoroquinolones and shows no cross-resistance to quinolones. NBTIs consist of three structural motifs. A structure activity relationship of the left hand motif 1,5-naphthyridine of oxabicyclooctane-linked NBTIs is described. Fifty five compounds were evaluated against a panel of key Gram-positive and Gram-negative strains of bacteria, as well as for hERG activity and five compounds were tested for in vivo efficacy in murine model of Staphylococcus aureus infection. These studies suggest that only a narrow range (activating and deactivating) of substitutions at C-2 and C-7 are tolerated for optimal antibacterial activity and spectrum. An alkoxy (methoxy) and CN at C-2, and a halogen and hydroxyl at C-7, appeared to be preferred in this series. Substitutions on the other three carbons generally have detrimental effect on the activity. No clear hERG activity SAR emerged from these substitutions.

Effects of Wrapping Number of Constituent Functional Yarns on Moisture Transferring/Antibacterial Knits

In this study, the PET/nylon/PET wrapped yarns are made by applying a double warp yarn process. The wrap materials are moisture transferring polyester (PET) yarns and antibacterial nylon yarns, while the core is PET yarns. Such wrapped yarns are made into moisture transferring/antibacterial knits, after which their mechanical properties, antibacterial activity, and water absorbency are evaluated. The test results show that the knits that are composed of wrapped yarns with a wrapping number being 10 turns/cm demonstrate optimal mechanical properties, antibacterial activity, and water absorbency.