Displaying publications 81 - 100 of 929 in total

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  1. Fulltext Synthesis, PASS-Predication and in Vitro Antimicrobial Activity of Benzyl 4-O-benzoyl-α-l-rhamnopyranoside Derivatives
    Matin MM, Nath AR, Saad O, Bhuiyan MM, Kadir FA, Abd Hamid SB, et al.
    Int J Mol Sci, 2016 Aug 27;17(9).
    PMID: 27618893 DOI: 10.3390/ijms17091412
    Benzyl α-l-rhamnopyranoside 4, obtained by both conventional and microwave assisted glycosidation techniques, was subjected to 2,3-O-isopropylidene protection to yield compound 5 which on benzoylation and subsequent deprotection of isopropylidene group gave the desired 4-O-benzoylrhamnopyranoside 7 in reasonable yield. Di-O-acetyl derivative of benzoate 7 was prepared to get newer rhamnopyranoside. The structure activity relationship (SAR) of the designed compounds was performed along with the prediction of activity spectra for substances (PASS) training set. Experimental studies based on antimicrobial activities verified the predictions obtained by the PASS software. Protected rhamnopyranosides 5 and 6 exhibited slight distortion from regular ¹C₄ conformation, probably due to the fusion of pyranose and isopropylidene ring. Synthesized rhamnopyranosides 4-8 were employed as test chemicals for in vitro antimicrobial evaluation against eight human pathogenic bacteria and two fungi. Antimicrobial and SAR study showed that the rhamnopyranosides were prone against fungal organisms as compared to that of the bacterial pathogens. Interestingly, PASS prediction of the rhamnopyranoside derivatives 4-8 were 0.49 < Pa < 0.60 (where Pa is probability 'to be active') as antibacterial and 0.65 < Pa < 0.73 as antifungal activities, which showed significant agreement with experimental data, suggesting rhamnopyranoside derivatives 4-8 were more active against pathogenic fungi as compared to human pathogenic bacteria thus, there is a more than 50% chance that the rhamnopyranoside derivative structures 4-8 have not been reported with antimicrobial activity, making it a possible valuable lead compound.
    Matched MeSH terms: Bacteria/drug effects
  2. Synthesis of some new 2-[4-(2-furoyl)-1-piperazinyl]-N-aryl/aralkyl acetamides as potent antibacterial agents
    Hussain G, Abbasi MA, Rehman A, Siddiqui SZ, Shah SAA, Ahmad I, et al.
    Pak J Pharm Sci, 2018 May;31(3):857-866.
    PMID: 29716866
    In this work, a new series of 2-[4-(2-furoyl)-1-piperazinyl]-N-aryl/aralkyl acetamides has been synthesized and evaluated for their antibacterial potential. The synthesis was initiated by the reaction of different aryl/aralkyl amines (1a-u) with 2-bromoacetylbromide (2) to obtain N-aryl/aralkyl-2-bromoacetamides (3a-u). Equimolar quantities of different N-aryl/aralkyl-2-bromoacetamides (3a-u) and 2-furoyl-1-piperazine (4) was allowed to react in acetonitrile and in the presence of K2CO3, to form 2-[4-(2-furoyl)-1-piperazinyl]-N-aryl/aralkyl acetamides (5a-u). The structural elucidation was done by EI-MS, IR and 1H-NMR techniques of all the synthesized compounds. All of the synthesized molecules were active against various Gram positive and Gram negative bacterial strains. Among them 5o and 5c showed very excellent MIC values. The cytotoxicity of the molecules was also checked to find their utility as possible therapeutic agents, where 5c (0.51%) and 5g (1.32%) are found to be least toxic in the series.
    Matched MeSH terms: Gram-Negative Bacteria
  3. Synthesis of poly(3-hydroxybutyrate-co-4-hydroxybutyrate)/chitosan/silver nanocomposite material with enhanced antimicrobial activity
    Rennukka M, Sipaut CS, Amirul AA
    Biotechnol Prog, 2014 Nov-Dec;30(6):1469-79.
    PMID: 25181613 DOI: 10.1002/btpr.1986
    This work aims to shed light in the fabrication of poly(3-hydroxybutyrate-co-44%-4-hydroxybutyrate)[P(3HB-co-44%4HB)]/chitosan-based silver nanocomposite material using different contents of silver nanoparticle (SNP); 1-9 wt%. Two approaches were applied in the fabrication; namely solvent casting and chemical crosslinking via glutaraldehyde (GA). A detailed characterization was conducted in order to yield information regarding the nanocomposite material. X-ray diffraction analysis exhibited the nature of the three components that exist in the nanocomposite films: P(3HB-co-4HB), chitosan, and SNP. In term of mechanical properties, tensile strength, and elongation at break were significantly improved up to 125% and 22%, respectively with the impregnation of the SNP. The melting temperature of the nanocomposite materials was increased whereas their thermal stability was slightly changed. Scanning electron microscopy images revealed that incorporation of 9 wt% of SNP caused agglomeration but the surface roughness of the material was significantly improved with the loading. Staphylococcus aureus and Escherichia coli were completely inhibited by the nanocomposite films with 7 and 9 wt% of SNP, respectively. On the other hand, degradation of the nanocomposite materials outweighed the degradation of the pure copolymer. These bioactive and biodegradable materials stand a good chance to serve the vast need of biomedical applications namely management and care of wound as wound dressing.
    Matched MeSH terms: Bacteria/drug effects
  4. Fulltext Synthesis of novel bisindolylmethane Schiff bases and their antibacterial activity
    Imran S, Taha M, Ismail NH, Khan KM, Naz F, Hussain M, et al.
    Molecules, 2014;19(8):11722-40.
    PMID: 25102118 DOI: 10.3390/molecules190811722
    In an effort to develop new antibacterial drugs, some novel bisindolylmethane derivatives containing Schiff base moieties were prepared and screened for their antibacterial activity. The synthesis of the bisindolylmethane Schiff base derivatives 3-26 was carried out in three steps. First, the nitro group of 3,3'-((4-nitrophenyl)-methylene)bis(1H-indole) (1) was reduced to give the amino substituted bisindolylmethane 2 without affecting the unsaturation of the bisindolylmethane moiety using nickel boride in situ generated. Reduction of compound 1 using various catalysts showed that combination of sodium borohydride and nickel acetate provides the highest yield for compound 2. Bisindolylmethane Schiff base derivatives were synthesized by coupling various benzaldehydes with amino substituted bisindolylmethane 2. All synthesized compounds were characterized by various spectroscopic methods. The bisindolylmethane Schiff base derivatives were evaluated against selected Gram-positive and Gram-negative bacterial strains. Derivatives having halogen and nitro substituent display weak to moderate antibacterial activity against Salmonella typhi, S. paratyphi A and S. paratyphi B.
    Matched MeSH terms: Gram-Negative Bacteria/drug effects*; Gram-Positive Bacteria/drug effects*
  5. Synthesis of cephradine metal complexes and its anti-bacterial evaluation
    Iqbal Hussain, Syed Salman, Sarwat Iftikhar, Samin Jan, Junaid Akhter, Muhammad Ramzan, et al.
    Sains Malaysiana, 2018;47:749-754.
    Cephradine belongs to the first generation cephalosporin having a broad range of anti-bacterial activities. In the
    present work, Cephradine wasreacted with different metal salts. These metal salts were Iron, Copper, Cobalt and Nickel
    salts. All the complexes of Cephradine metals were synthesized at room temperature using a mechanical vibrator.
    The reactions yielded the coordinated complexes within 5-10 min with improved product yield. The synthesized
    complexes were analyzed for their antibacterial power using disc diffused assay. All the Cephradine complexes showed
    powerful antibacterial activity. The Co, Cu, Ni and Sn complexes showed good antibacterial activities 18.5 mm by Cu
    complexes against S. typhi, 17 mm against B. subtillus 16.5 mm against S. aureus, 16 mm against S. coccus. Similarly
    Sn complexes exhibited 17 mm zone of inhibition against S. coccus and 15.5 mm against B. subtillus. Cobalt and Ni
    complexes also shed significant inhibition activities against bacterial pathogenic bacterial strains. The study is of
    particular importance and new, using mechanical vibrator for the first time. The product yield is also comparatively
    good with short reaction time.
    Matched MeSH terms: Anti-Bacterial Agents; Bacteria
  6. Synthesis of ZnO nanoparticles with chitosan as stabilizing agent and their antibacterial properties against Gram-positive and Gram-negative bacteria
    Yusof NAA, Zain NM, Pauzi N
    Int J Biol Macromol, 2019 Mar 01;124:1132-1136.
    PMID: 30496864 DOI: 10.1016/j.ijbiomac.2018.11.228
    Antibacterial activity of zinc oxide (ZnO) nanoparticles have received significant interest, particularly by the implementation of nanotechnology to synthesize particles in nanometer region. ZnO nanoparticles were successfully synthesized through microwave heating by using chitosan as a stabilizing agent and characterized by UV-vis, FTIR, XRD and FESEM-EDX. The aim of the present study is to determine the antibacterial activity of ZnO nanoparticles against Gram-positive bacterium Staphylococcus aureus (S. aureus) and Gram-negative bacterium Escherichia coli (E. coli). The antibacterial effect of ZnO nanoparticles was investigated for the inhibition zone and inactivation of cell growth. The absorption of ZnO nanoparticles was found to be around 360 nm. FTIR results showed the stretching mode of ZnO nanoparticles at 475 cm-1 of the absorption band. EDX results indicated that ZnO nanoparticles have been successfully formed with an atomic percentage of zinc and oxygen at 23.61 and 46.57% respectively. X-ray diffraction result was confirmed the single-phase formation of ZnO nanoparticles and the particle sizes were observed to be around 50 to 130 nm. The results showed that ZnO nanoparticles have displayed inhibition zone of 16 and 13 mm against S. aureus and E. coli respectively. Gram-negative bacteria seemed to be more resistant to ZnO nanoparticles than Gram-positive bacteria.
    Matched MeSH terms: Gram-Negative Bacteria; Gram-Positive Bacteria
  7. Synthesis of 2-Furyl[(4-aralkyl)-1-piperazinyl]methanone derivatives as suitable antibacterial agents with mild cytotoxicity
    Abbasi MA, Nazeer MM, Rehman A, Siddiqui SZ, Hussain G, Shah SA, et al.
    Pak J Pharm Sci, 2018 Nov;31(6):2477-2485.
    PMID: 30473521
    The aim of the present research work was synthesis of some 2-furyl[(4-aralkyl)-1-piperazinyl]methanone derivatives and to ascertain their antibacterial potential. The cytotoxicity of these molecules was also checked to find out their utility as possible therapeutic agents. The synthesis was initiated by reacting furyl(-1-piperazinyl)methanone (1) in N,N-dimethylformamide (DMF) and lithium hydride with different aralkyl halides (2a-j) to afford 2-furyl[(4-aralkyl)-1-piperazinyl]methanone derivatives (3a-j). The structural confirmation of all the synthesized compounds was done by IR, EI-MS, 1H-NMR and 13C-NMR spectral techniques and through elemental analysis. The results of in vitro antibacterial activity of all the synthesized compounds were screened against Gram-negative (S. typhi, E. coli, P. aeruginosa) and Gram-positive (B. subtilis, S. aureus) bacteria and were found to be decent inhibitors. Amongst the synthesized molecules, 3e showed lowest minimum inhibitory concentration MIC = 7.52±0.μg/mL against S. Typhi, credibly due to the presence of 2-bromobenzyl group, relative to the reference standard, ciprofloxacin, having MIC = 7.45±0.58μg/mL.
    Matched MeSH terms: Gram-Negative Bacteria/drug effects*; Gram-Negative Bacteria/growth & development; Gram-Positive Bacteria/drug effects*; Gram-Positive Bacteria/growth & development
  8. Synthesis and characterization of silver nanoparticles using fruit extract of Momordica cymbalaria and assessment of their in vitro antimicrobial, antioxidant and cytotoxicity activities
    Swamy MK, Akhtar MS, Mohanty SK, Sinniah UR
    Spectrochim Acta A Mol Biomol Spectrosc, 2015 Dec 5;151:939-44.
    PMID: 26186612 DOI: 10.1016/j.saa.2015.07.009
    Plant mediated synthesis of nanoparticles has been considered as green route and a reliable technique for the synthesis of nanoparticles due to its eco-friendly approach. In this study, we report a simple and eco-friendly approach for the synthesis of silver nanoparticles (AgNPs) using methanolic Momordica cymbalaria fruit extract as reducing agent. The fruit extract of M. cymbalaria exposed to AgNO3 solution showed the change in color from green to light yellow at room temperature within 1h of incubation confirms the synthesis of AgNPs. UV-vis spectra analysis revealed that the synthesized AgNPs had a sharp surface plasmon resonance at around 450 nm, while, the X-ray Diffraction (XRD) patterns confirmed distinctive peaks indices to the crystalline planes of the face centered cubic silver. The Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) analysis results confirmed the presence of spherical shaped AgNPs by a huge disparity in the particle size distribution with an average size of 15.5 nm. The synthesized AgNPs showed strong antibacterial activity against all the tested multidrug resistant human pathogenic bacterial strains and also exhibited highest free radical scavenging activity (74.2%) compared to fruit extract (60.4%). Moreover, both fruit extract and the synthesized AgNPs showed the cytotoxicity towards Rat L6 skeletal muscle cell line at different concentrations, but the highest inhibition percentage was recorded for AgNPs at concentration of 100 μg/ml.
    Matched MeSH terms: Anti-Bacterial Agents; Bacteria
  9. Synthesis and characterization of gentamicin loaded ZSM-5 scaffold: Cytocompatibility and antibacterial activity
    Nazemi N, Rajabi N, Aslani Z, Kharaziha M, Kasiri-Asgarani M, Bakhsheshi-Rad HR, et al.
    J Biomater Appl, 2023 Jan;37(6):979-991.
    PMID: 36454961 DOI: 10.1177/08853282221140672
    Porous structure, biocompatibility and biodegradability, large surface area, and drug-loading ability are some remarkable properties of zeolite structure, making it a great possible option for bone tissue engineering. Herein, we evaluated the potential application of the ZSM-5 scaffold encapsulated GEN with high porosity structure and significant antibacterial properties. The space holder process has been employed as a new fabrication method with interconnected pores and suitable mechanical properties. In this study, for the first time, ZSM-5 scaffolds with GEN drug-loading were fabricated with the space holder method. The results showed excellent open porosity in the range of 70-78% for different GEN concentrations and appropriate mechanical properties. Apatite formation on the scaffold surface was determined with Simulation body fluid (SBF), and a new bone-like apatite layer shaping on all samples confirmed the in vitro bioactivity of ZSM-5-GEN scaffolds. Also, antibacterial properties were investigated against both gram-positive and gram-negative bacteria. The incorporation of various amounts of GEN increased the inhibition zone from 24 to 28 (for E. coli) and 26 to 37 (for S. aureus). In the culture with MG63 cells, great cell viability and high cell proliferation after 7 days of culture were determined.
    Matched MeSH terms: Gram-Negative Bacteria; Gram-Positive Bacteria
  10. Synthesis and biological evaluation of novel substituted 1,3,4-thiadiazole and 2,6-di aryl substituted imidazo [2,1-b] [1,3,4] thiadiazole derivatives
    Chandrakantha B, Isloor AM, Shetty P, Fun HK, Hegde G
    Eur J Med Chem, 2014 Jan;71:316-23.
    PMID: 24321835 DOI: 10.1016/j.ejmech.2013.10.056
    A new series of N-[5-(4-(alkyl/aryl)-3-nitro-phenyl)-[1,3,4-thiadiazol-2-yl]-2,2-dimethyl-propionamide 4 (a-l) and 6-(4-Methoxy-phenyl)-2-(4-alkyl/aryl)-3-nitro-phenyl)-Imidazo [2,1-b] [1,3,4] thiadiazole 6 (a-l) were synthesized starting from 5-(4-Fluoro-3-nitro-phenyl)-[1,3,4] thiadiazole-2-ylamine. The synthesized compounds were characterized by IR, NMR, mass spectral and elemental analysis. All the compounds were tested for antibacterial and antifungal activities. The antimicrobial activities of the compounds were assessed by well plate method (zone of inhibition). Compounds 4a, 4c and 6e, 6g displayed appreciable activity at the concentration 0.5-1.0 mg/mL.
    Matched MeSH terms: Anti-Bacterial Agents/chemical synthesis; Anti-Bacterial Agents/pharmacology*; Anti-Bacterial Agents/chemistry*; Bacteria/drug effects; Bacterial Infections/drug therapy
  11. Synthesis and biological evaluation of indole core-based derivatives with potent antibacterial activity against resistant bacterial pathogens
    Hong W, Li J, Chang Z, Tan X, Yang H, Ouyang Y, et al.
    J Antibiot (Tokyo), 2017 Jul;70(7):832-844.
    PMID: 28465626 DOI: 10.1038/ja.2017.55
    The emergence of drug resistance in bacterial pathogens is a growing clinical problem that poses difficult challenges in patient management. To exacerbate this problem, there is currently a serious lack of antibacterial agents that are designed to target extremely drug-resistant bacterial strains. Here we describe the design, synthesis and antibacterial testing of a series of 40 novel indole core derivatives, which are predicated by molecular modeling to be potential glycosyltransferase inhibitors. Twenty of these derivatives were found to show in vitro inhibition of Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus. Four of these strains showed additional activity against Gram-negative bacteria, including extended-spectrum beta-lactamase producing Enterobacteriaceae, imipenem-resistant Klebsiella pneumoniae and multidrug-resistant Acinetobacter baumanii, and against Mycobacterium tuberculosis H37Ra. These four compounds are candidates for developing into broad-spectrum anti-infective agents.
    Matched MeSH terms: Gram-Negative Bacteria/drug effects*; Gram-Positive Bacteria/drug effects*
  12. Synthesis and antimicrobial properties of some new thiazolyl coumarin derivatives
    Arshad A, Osman H, Bagley MC, Lam CK, Mohamad S, Zahariluddin AS
    Eur J Med Chem, 2011 Sep;46(9):3788-94.
    PMID: 21712145 DOI: 10.1016/j.ejmech.2011.05.044
    Two novel series of hydrazinyl thiazolyl coumarin derivatives have been synthesized and fully characterized by IR, (1)H NMR, (13)C NMR, elemental analysis and mass spectral data. The structures of some compounds were further confirmed by X-ray crystallography. All of these derivatives, 10a-d and 15a-h, were screened in vitro for antimicrobial activity against various bacteria species including Mycobacterium tuberculosis and Candida albicans. The compounds 10c, 10d and 15e exhibited very good activities against all of the tested microbial strains.
    Matched MeSH terms: Gram-Negative Bacteria/drug effects; Gram-Positive Bacteria/drug effects
  13. Fulltext Synthesis and antibacterial evaluation of some novel imidazole and benzimidazole sulfonamides
    Al-Mohammed NN, Alias Y, Abdullah Z, Shakir RM, Taha EM, Hamid AA
    Molecules, 2013 Sep 26;18(10):11978-95.
    PMID: 24077176 DOI: 10.3390/molecules181011978
    Several new substituted sulfonamide compounds were synthesized and their structures were confirmed by ¹H-NMR, ¹³C-NMR, FT-IR, and mass spectroscopy. The antibacterial activities of the synthesized compounds were screened against standard strains of six Gram positive and four Gram negative bacteria using the microbroth dilution assay. Most of the compounds studied showed promising activities against both types of bacteria.
    Matched MeSH terms: Gram-Negative Bacteria/drug effects; Gram-Positive Bacteria/drug effects
  14. Synthesis and anti-microbial potencies of 1-(2-hydroxyethyl)-3-alkylimidazolium chloride ionic liquids: microbial viabilities at different ionic liquids concentrations
    Hossain MI, El-Harbawi M, Alitheen NB, Noaman YA, Lévêque JM, Yin CY
    Ecotoxicol Environ Saf, 2013 Jan;87:65-9.
    PMID: 23107478 DOI: 10.1016/j.ecoenv.2012.09.020
    Three 1-(2-hydroxyethyl)-3-alkylimidazolium chloride room temperature ionic liquids (ILs) [2OHimC(n)][Cl]; (n=0, 1, 4) have been synthesized from the appropriate imidazole precursors and characterized by IR and NMR spectroscopies and elemental analysis. Their anti-microbial activities were investigated using the well-diffusion method. The viabilities of Escherichia coli, Aeromonas hydrophila, Listeria monocytogenes and Salmonella enterica as a function of IL concentrations were studied. The minimal inhibitory concentrations (MICs) and EC₅₀ values for the present ILs were within the concentration range from 60 to 125 mM and 23 to 73 mM. The anti-microbial potencies of the present ILs were compared to a standard antibiotic, gentamicin. The finding affords additional perspective on the level of ILs toxicity to aquatic lifeforms and yet, this characteristic can be readily harnessed to detect microbial growth and activity.
    Matched MeSH terms: Anti-Bacterial Agents/chemical synthesis*; Anti-Bacterial Agents/pharmacology*; Anti-Bacterial Agents/chemistry; Bacteria/drug effects*
  15. Fulltext Synergy of antibacterial and antioxidant activities from crude extracts and peptides of selected plant mixture
    Shami AM, Philip K, Muniandy S
    BMC Complement Altern Med, 2013 Dec 16;13:360.
    PMID: 24330547 DOI: 10.1186/1472-6882-13-360
    BACKGROUND: A plant mixture containing indigenous Australian plants was examined for synergistic antimicrobial activity using selected test microorganisms. This study aims to investigate antibacterial activities, antioxidant potential and the content of phenolic compounds in aqueous, ethanolic and peptide extracts of plant mixture.

    METHODS: Well diffusion, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays were used to test antibacterial activity against four pathogenic bacteria namely Staphylococcus aureus, Escherichia coli, Bacillus cereus, and Pseudomonas aeruginosa. DPPH (2, 2-diphenyl-1- picrylhydrazyl) and superoxide dismutase (SOD) assays were used to evaluate antioxidant activity. HPLC and gel filtration were used for purification of the peptides. Scanning electron microscope was applied to investigate the mode of attachment of the peptides on target microbial membranes.

    RESULTS: Aqueous extraction of the mixture showed no inhibition zones against all the test bacteria. Mean diameter of inhibition zones for ethanol extraction of this mixture attained 8.33 mm, 7.33 mm, and 6.33 mm against S. aureus at corresponding concentrations of 500, 250 and 125 mg/ml while E .coli showed inhibition zones of 9.33 mm, 8.00 mm and 6.66 mm at the same concentrations. B. cereus exhibited inhibition zones of 11.33 mm, 10.33 mm and 10.00 mm at concentrations of 500, 250 and 125 mg/ml respectively. The peptide extract demonstrated antibacterial activity against S. aureus, E. coli and B. cereus. The MIC and MBC values for ethanol extracts were determined at 125 mg/ml concentration against S. aureus and E. coli and B. cereus value was 31.5 mg/ml. MIC and MBC values showed that the peptide extract was significantly effective at low concentration of the Australian plant mixture (APM). Phenolic compounds were detected in hot aqueous and ethanolic extracts of the plant mixture. Hot aqueous, ethanol and peptides extracts also exhibited antioxidant activities.

    CONCLUSIONS: It was concluded that APM possessed good antibacterial and antioxidant activities following extraction with different solvents. The results suggest that APM provide a new source with antibacterial agents and antioxidant activity for nutraceutical or medical applications.

    Matched MeSH terms: Anti-Bacterial Agents/pharmacology*; Anti-Bacterial Agents/chemistry; Bacteria/drug effects
  16. Fulltext Synergistic effects of Persicaria odorata (daun kesom) leaf extracts with standard antibiotics on pathogenic bacteria
    Ridzuan, P.M., Hairul Aini Hamzah, Anis Shah, Norazian Mohd Hassan, Baharudin Roesnita
    International Medical Journal Malaysia, 2017;16(2):27-32.
    MyJurnal
    Antibacterial activity of different types of P. odorata leaf extracts was evaluated in combination with
    standard antibiotics. Persicaria. odorata leaves were extracted with n-hexane (n-hex), dichloromethane
    (DCM) and methanol (MeOH). Each extract was applied on vancomycin (30µg), erythromycin (15µg) and
    gentamicin (10µg) discs, respectively. Disk diffusion method was used to evaluate the synergistic activity of
    each combination on Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes,
    Streptococcus pneumoniae, Pseudomonas aeruginosa, Salmonella typhi, and Escherichia coli. Minimum
    inhibitory concentration (MIC) and gas chromatography mass spectrometry (GCMS) analysis was performed on
    the active extract. Synergistic effects seen were mainly from the n-hex+antibiotics combinations, mainly on
    the Gram-positive bacteria (7 additive, 5 antagonistic), with MIC range from 50 µg/ml to 100 µg/ml, as well
    as Gram-negative bacteria (2 additive, 2 indifferent, 5 antagonistic). In particular, synergism showed by the
    combination of n-hex+van were all additive against the susceptible bacteria. DCM extract combination
    showed synergistic effects on three Gram-positive species (S. aureus, S. epidermidis, S. pyogenes).
    Meanwhile, MeOH+antibiotics combination showed significant additive synergistic effects (p
    Matched MeSH terms: Gram-Negative Bacteria; Gram-Positive Bacteria
  17. Synergistic antibacterial actions of graphene oxide and antibiotics towards bacteria and the toxicological effects of graphene oxide on human epidermal keratinocytes
    Pulingam T, Thong KL, Appaturi JN, Nordin NI, Dinshaw IJ, Lai CW, et al.
    Eur J Pharm Sci, 2020 Jan 15;142:105087.
    PMID: 31626968 DOI: 10.1016/j.ejps.2019.105087
    Graphene oxide (GO) has displayed antibacterial activity that has been investigated in the past, however, information on synergistic activity of GO with conventional antibiotics is still lacking. The objectives of the study were to determine the combinatorial actions of GO and antibiotics against Gram-positive and Gram-negative bacteria and the toxicological effects of GO towards human epidermal keratinocytes (HaCaT). Interactions at molecular level between GO and antibiotics were analyzed using Attenuated Total Reflectance-Fourier-transform infrared spectroscopy (ATR-FTIR). Changes in the antibacterial activity of antibiotics towards bacteria through the addition of GO was investigated. Toxicity of GO towards HaCaT cells were examined as skin cells play a role as the first line of defense of the human body. The ATR-FTIR characterizations of GO and antibiotics showed adsorption of tested antibiotics onto GO. The combinatorial antibacterial activity of GO and antibiotics were found to increase when compared to GO or antibiotic alone. This was attributed to the ability of GO to disrupt bacterial membrane to allow for better adsorption of antibiotics. Cytotoxicity of GO was found to be dose-dependent towards HaCaT cell line, it is found to impose negligible toxic effects against the skin cells at concentration below 100 μg/mL.
    Matched MeSH terms: Gram-Negative Bacteria/drug effects*; Gram-Positive Bacteria/drug effects*
  18. Symbiotic interaction of endophytic bacteria with arbuscular mycorrhizal fungi and its antagonistic effect on Ganoderma boninense
    Sundram S, Meon S, Seman IA, Othman R
    J Microbiol, 2011 Aug;49(4):551-7.
    PMID: 21887636 DOI: 10.1007/s12275-011-0489-3
    Endophytic bacteria (Pseudomonas aeruginosa UPMP3 and Burkholderia cepacia UMPB3), isolated from within roots of oil palm (Elaeis guineensis Jacq.) were tested for their presymbiotic effects on two arbuscular mcorrhizal fungi, Glomus intraradices UT126 and Glomus clarum BR152B). These endophytic bacteria were also tested for antagonistic effects on Ganoderma boninense PER 71, a white wood rot fungal pathogen that causes a serious disease in oil palm. Spore germination and hyphal length of each arbuscular mycorrhizal fungal (AMF) pairing with endophytic bacteria was found to be significantly higher than spores plated in the absence of bacteria. Scanning electron microscopy (SEM) showed that the endophytic bacteria were scattered, resting or embedded on the surface hyaline layer or on the degraded walls of AMF spores, possibly feeding on the outer hyaline spore wall. The antagonistic effect of the endophytic bacteria was expressed as severe morphological abnormalities in the hyphal structures of G. boninense PER 71. The effects of the endophytic bacteria on G. boninense PER 71 hyphal structures were observed clearly under SEM. Severe inter-twisting, distortion, lysis and shriveling of the hyphal structures were observed. This study found that the effect of endophytic bacteria on G. intraradices UT126 and G. clarum BR152B resembled that of a mycorrhiza helper bacteria (MHB) association because the association significantly promoted AMF spore germination and hyphal length. However, the endophytic bacteria were extremely damaging to G. boninense PER 71.
    Matched MeSH terms: Bacteria/isolation & purification; Bacteria/metabolism*; Bacteria/ultrastructure
  19. Fulltext Sustainable drug release from polycaprolactone coated chitin-lignin gel fibrous scaffolds
    Abudula T, Gauthaman K, Mostafavi A, Alshahrie A, Salah N, Morganti P, et al.
    Sci Rep, 2020 11 24;10(1):20428.
    PMID: 33235239 DOI: 10.1038/s41598-020-76971-w
    Non-healing wounds have placed an enormous stress on both patients and healthcare systems worldwide. Severe complications induced by these wounds can lead to limb amputation or even death and urgently require more effective treatments. Electrospun scaffolds have great potential for improving wound healing treatments by providing controlled drug delivery. Previously, we developed fibrous scaffolds from complex carbohydrate polymers [i.e. chitin-lignin (CL) gels]. However, their application was limited by solubility and undesirable burst drug release. Here, a coaxial electrospinning is applied to encapsulate the CL gels with polycaprolactone (PCL). Presence of a PCL shell layer thus provides longer shelf-life for the CL gels in a wet environment and sustainable drug release. Antibiotics loaded into core-shell fibrous platform effectively inhibit both gram-positive and -negative bacteria without inducting observable cytotoxicity. Therefore, PCL coated CL fibrous gel platforms appear to be good candidates for controlled drug release based wound dressing applications.
    Matched MeSH terms: Gram-Negative Bacteria/drug effects; Gram-Negative Bacteria/growth & development; Gram-Positive Bacteria/drug effects; Gram-Positive Bacteria/growth & development
  20. Surveillance study of bacteraemic episodes in febrile neutropenic children
    Ariffin H, Navaratnam P, Lin HP
    Int J Clin Pract, 2002 May;56(4):237-40.
    PMID: 12074201
    We prospectively studied the type, frequency and outcome of infections in 513 patients with 762 consecutive episodes of febrile neutropenia (FN) over a five-year period between 1995 and 1999 in a single paediatric oncology unit. The findings were then compared with a similar study carried out in our unit between 1990 and 1994. The types of bacterial isolates and sensitivity patterns were also studied to identify trends and to gauge the suitability of antibiotics chosen for empirical therapy. Bacteraemia was documented in 35.4% of FN episodes, although 70% of patients did not have an obvious site of sepsis. The majority of isolates (61.9%) were gram-negative bacteria, a consistent finding throughout the study period. Resistance to ceftazidime, amikacin and imipenem among gram-negative bacteria was 26.3%, 21.2% and 0.7%, respectively. Methicillin resistance among gram-positive bacteria was 26.3%, while no vancomycin-resistant bacteria were encountered. There were 36 sepsis-related deaths. Factors associated with a fatal outome were prolonged capillary refill time, hypotension, fever above 39 degrees C and pneumonia. Rapid neutrophil recovery was associated with a good prognosis. A change to our current choice of empirical antibiotics for FN, comprising ceftazidime/ceftriaxone and amikacin appears necessary because of the relatively high resistance rates found.
    Matched MeSH terms: Gram-Negative Bacteria/isolation & purification*
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