Displaying publications 61 - 80 of 849 in total

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  1. Tan YN, Ayob MK, Wan Yaacob WA
    Food Chem, 2013 Jan 1;136(1):279-84.
    PMID: 23017424 DOI: 10.1016/j.foodchem.2012.08.012
    Palm kernel cake (PKC), the most useful by-product resulted from palm kernel oil production. In this study, PKC-derived protein product was found suitable for use as an antimicrobial agent with potent antibacterial activity, particularly against Bacillus species, after enzymatic hydrolysis with alcalase. The hydrolysate was further purified by gel filtration chromatography. The purified fraction was found to have 14.63±0.70% (w/w) protein, a molecular mass of 2.4kDa and low hemolytic activity (<50% hemolysis of human erythrocytes at concentration of 1000μg/ml). The presence of lysine and the major component lauric acid derivative, as indicated by electrospray ionisation-mass spectrometry (ESI-MS) direct infusion and nuclear magnetic resonance (NMR) spectroscopy, may have contributed to the antibacterial effect of purified PKC fraction. This study suggests that the antibacterial PKC compound may be not a pure peptide but instead a peptide-containing compound high in lauric acid derivative.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacology
  2. Chin SC, Abdullah N, Siang TW, Wan HY
    J Microbiol, 2005 Jun;43(3):251-6.
    PMID: 15995642
    In this study, we assessed the susceptibility of 12 Lactobacillus strains, all of which had been isolated from the gastrointestinal tracts of chicken, to three antibiotics (chloramphenicol, erythromycin and tetracycline) used commonly as selective markers in transformation studies of lactic acid bacteria. Among these strains, 17%, 58%, and 25% were found to exhibit a high degree of resistance to 200 microg/ml of tetracycline, erythromycin, and chloramphenicol, respectively. Seven of the 12 Lactobacillus strains exhibiting resistance to at least 50 microg/ml of chloramphenicol or erythromycin, and five strains exhibiting resistance to at least 50 microg/ml of tetracycline, were subsequently subjected to plasmid curing with chemical curing agents, such as novobiocin, acriflavin, SDS, and ethidium bromide. In no cases did the antibiotic resistance of these strains prove to be curable, with the exception of the erythromycin resistance exhibited by five Lactobacillus strains (L. acidophilus I16 and I26, L. fermentum I24 and C17, and L. brevis C10). Analysis of the plasmid profiles of these five cured derivatives revealed that all of the derivatives, except for L. acidophilus I16, possessed profiles similar to those of wild-type strains. The curing of L. acidophilus I16 was accompanied by the loss of 4.4 kb, 6.1 kb, and 11.5 kb plasmids.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacology
  3. Chandrawathani P, Adnan M, Waller PJ
    Vet Parasitol, 1999 May;82(4):305-10.
    PMID: 10384906
    The faecal egg count reduction test (FECRT) was conducted on 39 sheep farms and 9 goat farms located in Peninsular Malaysia. The anthelmintic groups used in these tests were the benzimidazoles, levamisole, the benzimidazole/levamisole combination, macrocyclic lactones and closantel. Results indicated that the prevalence of resistance to the benzimidazole group was high, with approximately 50% of the sheep farms and 75% of the goat farms having resistant nematode parasite populations present. Resistance to levamisole, closantel and ivermectin was also detected. Differentiation of the infective larvae derived from faecal cultures indicated that by far the most predominant parasite species was Haemonchus contortus.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacology
  4. Asekunowo PO, Haque RA, Razali MR, Avicor SW, Wajidi MFF
    Eur J Med Chem, 2018 Apr 25;150:601-615.
    PMID: 29550733 DOI: 10.1016/j.ejmech.2018.03.029
    A series of four benzimidazolium based nitrile-functionalized mononuclear-Ag(I)-N-heterocyclic carbene and binuclear-Ag(I)-N-heterocyclic carbene (Ag(I)-NHC) hexafluorophosphate complexes (5b-8b) were synthesized by reacting the corresponding hexafluorophosphate salts (1b-4b) with Ag2O in acetonitrile, respectively. These compounds were characterized by 1H NMR, 13C NMR, IR, UV-visible spectroscopic techniques, elemental analyses and molar conductivity. Additionally, 8b was structurally characterized by single crystal X-ray diffraction technique. Preliminary in vitro antibacterial evaluation was conducted for all the compounds against two standard bacteria; gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacterial strains. Most of the Ag(I)-NHC complexes (5b-8b) showed moderate to good antibacterial activity with MIC values in the range of 12.5-100 μg/mL. Especially, compound 8b exhibited promising anti-Staphylococcus aureus activity with a low MIC value (12.5 μg/mL). However, all the hexafluorophosphate salts (1b-4b) were inactive against the bacteria strains. The preliminary interactive investigation revealed that the most active compound, 8b, could effectively intercalate into DNA to form 8b-DNA complex which shows a better binding ability for DNA (Kb = 3.627 × 106) than the complexes 5b-7b (2.177 × 106, 8.672 × 105 and 6.665 × 105, respectively). Nuclease activity of the complexes on plasmid DNA and Aedes albopictus genomic DNA was time-dependent, although minimal. The complexes were larvicidal to the mosquito, with 5b, 6b and 8b being highly active. Developmental progression from the larval to the adult stage was affected by the complexes, progressively being toxic to the insect's development with increasing concentration. These indicate the potential use of these complexes as control agents against bacteria and the dengue mosquito Ae. albopictus.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacology*
  5. WHO Western Pacific Gonococcal Antimicrobial Surveillance Programme
    Commun Dis Intell Q Rep, 2006;30(4):430-3.
    PMID: 17330383
    The World Health Organization Western Pacific Region Gonococcal Antimicrobial Surveillance Programme examined about 8,700 isolates of Neisseria gonorrhoeae from 15 countries for resistance to antibiotics in 2005. High to very high rates of resistance to penicillins and quinolones persisted in most centres. Increasing numbers of gonococci with decreased susceptibility to third generation cephalosporins were found in several countries. There were infrequent instances of spectinomycin resistance.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacology*
  6. Singh S, Agarwal R, Razak ZA, Ngu R, Nyein LL, Vasudevan S, et al.
    J Ocul Pharmacol Ther, 2018 01 17;34(1-2):214-223.
    PMID: 29341837 DOI: 10.1089/jop.2017.0098
    PURPOSE: Pseudomonas aeruginosa is the most common causative organism for contact lens-associated corneal ulcer and is commonly treated with fluoroquinolones. With the emergence of resistant strains, it is important to investigate alternative therapies. Despite well-established efficacy of tazocin against systemic Pseudomonas infections, its topical use for the treatment of Pseudomonas keratitis has not been described, hence this study was aimed to find the ocular permeation of Tazocin and its efficacy in treating keratitis in rabbit eyes.

    METHODS: We investigated the ocular permeation of topical tazocin after single drop application in normal rabbit eyes by estimating piperacillin and tazobactam concentrations in cornea, aqueous, and vitreous using a validated LC-MS/MS method. Furthermore, we determined the efficacy of repeated dose administration of tazocin against experimentally induced P. aeruginosa keratitis in rabbits in comparison to moxifloxacin. To determine the efficacy, clinical examination, histopathological examination, and estimation of bacterial load and inflammatory cytokines in cornea were done.

    RESULTS: Significant corneal concentration of piperacillin and tazobactam was detected in normal rabbit corneas after single dose treatment with tazocin. In rabbits with Pseudomonas-induced keratitis, topical tazocin caused significant clinical and histopathological improvement. This improvement was associated with reduction in corneal bacterial load and inflammatory cytokines. Compared to moxifloxacin 0.5%, tazocin treated group showed greater clinical response which was associated with higher interleukin (IL)-1β, lower tumor necrosis factor (TNF)-α, a comparable level of IL-8, greater reduction in corneal bacterial load, and lesser inflammatory cell infiltration.

    CONCLUSION: Tazocin showed good ocular penetration and was effective in treatment of Pseudomonas induced keratitis in rabbits.

    Matched MeSH terms: Anti-Bacterial Agents/pharmacology*
  7. Chabattula SC, Gupta PK, Govarthanan K, Varadaraj S, Rayala SK, Chakraborty D, et al.
    Appl Biochem Biotechnol, 2024 Jan;196(1):382-399.
    PMID: 37133677 DOI: 10.1007/s12010-023-04555-1
    Inorganic nanoparticles (NPs) have played an important role as nano-drug delivery systems during cancer therapy in recent years. These NPs can carry cancer therapeutic agents. Due to this, they are considered a promising ancillary to traditional cancer therapies. Among inorganic NPs, Zinc Oxide (ZnO) NPs have been extensively utilized in cellular imaging, gene/drug delivery, anti-microbial, and anti-cancerous applications. In this study, a rapid and cost-effective method was used to synthesize Nat-ZnO NPs using the floral extract of the Nyctanthes arbor-tristis (Nat) plant. Nat-ZnO NPs were physicochemically characterized and tested further on in vitro cancer models. The average hydrodynamic diameter (Zaverage) and the net surface charge of Nat-ZnO NPs were 372.5 ± 70.38 d.nm and -7.03 ± 0.55 mV, respectively. Nat-ZnO NPs exhibited a crystalline nature. HR-TEM analysis showed the triangular shape of NPs. Furthermore, Nat-ZnO NPs were also found to be biocompatible and hemocompatible when tested on mouse fibroblast cells and RBCs. Later, the anti-cancer activity of Nat-ZnO NPs was tested on lung and cervical cancer cells. These NPs displayed potent anti-cancer activity and induced programmed cell death in cancer cells.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacology
  8. Chabattula SC, Patra B, Gupta PK, Govarthanan K, Rayala SK, Chakraborty D, et al.
    Appl Biochem Biotechnol, 2024 Feb;196(2):1058-1078.
    PMID: 37318689 DOI: 10.1007/s12010-023-04582-y
    Metal/Metal Oxide nanoparticles (M/MO NPs) exhibit potential biomedical applications due to their tunable physicochemical properties. Recently, the biogenic synthesis of M/MO NPs has gained massive attention due to their economical and eco-friendly nature. In the present study, Nyctanthes arbor-tristis (Nat) flower extract-derived Zinc Ferrite NPs (Nat-ZnFe2O4 NPs) were synthesized and physicochemically characterized by FTIR, XRD, FE-SEM, DLS, and other instruments to study their crystallinity, size, shape, net charge, presence of phytocompounds on NP's surface and several other features. The average particle size of Nat-ZnFe2O4 NPs was approx. 25.87 ± 5.67 nm. XRD results showed the crystalline nature of Nat-ZnFe2O4 NPs. The net surface charge on NPs was -13.28 ± 7.18 mV. When tested on mouse fibroblasts and human RBCs, these NPs were biocompatible and hemocompatible. Later, these Nat-ZnFe2O4 NPs exhibited potent anti-neoplastic activity against pancreatic, lung, and cervical cancer cells. In addition, NPs induced apoptosis in tested cancer cells through ROS generation. These in vitro studies confirmed that Nat-ZnFe2O4 NPs could be used for cancer therapy. Moreover, further studies are recommended on ex vivo platforms for future clinical applications.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacology
  9. Deris ZZ, Akter J, Sivanesan S, Roberts KD, Thompson PE, Nation RL, et al.
    J Antibiot (Tokyo), 2014 Feb;67(2):147-51.
    PMID: 24169795 DOI: 10.1038/ja.2013.111
    Polymyxin B and colistin were examined for their ability to inhibit the type II NADH-quinone oxidoreductases (NDH-2) of three species of Gram-negative bacteria. Polymyxin B and colistin inhibited the NDH-2 activity in preparations from all of the isolates in a concentration-dependent manner. The mechanism of NDH-2 inhibition by polymyxin B was investigated in detail with Escherichia coli inner membrane preparations and conformed to a mixed inhibition model with respect to ubiquinone-1 and a non-competitive inhibition model with respect to NADH. These suggest that the inhibition of vital respiratory enzymes in the bacterial inner membrane represents one of the secondary modes of action for polymyxins.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacology
  10. Angers-Loustau A, Petrillo M, Bengtsson-Palme J, Berendonk T, Blais B, Chan KG, et al.
    F1000Res, 2018;7.
    PMID: 30026930 DOI: 10.12688/f1000research.14509.2
    Next-Generation Sequencing (NGS) technologies are expected to play a crucial role in the surveillance of infectious diseases, with their unprecedented capabilities for the characterisation of genetic information underlying the virulence and antimicrobial resistance (AMR) properties of microorganisms.  In the implementation of any novel technology for regulatory purposes, important considerations such as harmonisation, validation and quality assurance need to be addressed.  NGS technologies pose unique challenges in these regards, in part due to their reliance on bioinformatics for the processing and proper interpretation of the data produced.  Well-designed benchmark resources are thus needed to evaluate, validate and ensure continued quality control over the bioinformatics component of the process.  This concept was explored as part of a workshop on "Next-generation sequencing technologies and antimicrobial resistance" held October 4-5 2017.   Challenges involved in the development of such a benchmark resource, with a specific focus on identifying the molecular determinants of AMR, were identified. For each of the challenges, sets of unsolved questions that will need to be tackled for them to be properly addressed were compiled. These take into consideration the requirement for monitoring of AMR bacteria in humans, animals, food and the environment, which is aligned with the principles of a "One Health" approach.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacology*
  11. Wong KC, Hamid A, Eldeen IM, Asmawi MZ, Baharuddin S, Abdillahi HS, et al.
    Nat Prod Res, 2012;26(9):850-8.
    PMID: 21999629 DOI: 10.1080/14786419.2010.551770
    A new sesquiterpenoid, 1α,4β,7β-eudesmanetriol (1), was isolated together with the known compounds 1β,4β,7β-eudesmanetriol (2) and oplopanone (3) from the rhizomes of Homalomena sagittifolia. The structures of these compounds were determined by extensive spectral analyses. The compounds 1 and 2 inhibited growth of Pseudomonas stutzeri with a MIC value of 117 µM when evaluated for antibacterial activity using the minimum concentration assay. Both these compounds showed remarkable activities against acetylcholinesterase enzyme with IC(50) values ranging between 25 and 26 µM. The isolation of these sesquiterpenoids and their biological activities observed in this study support the reported traditional uses of H. sagittifolia for the treatment of microbial related diseases and central nervous system disorders.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacology
  12. Ariffin N, Hasan H, Ramli N, Ibrahim NR, Taib F, Rahman AA, et al.
    Am J Infect Control, 2012 Aug;40(6):572-5.
    PMID: 22854380 DOI: 10.1016/j.ajic.2012.02.032
    Intrahospital variations in antimicrobial profiles may be related to many factors. This study compared causative agents of nosocomial bloodstream infections between a neonatal intensive care unit (NICU) that adopted a ward-tailored antibiotic policy and adult intensive care units (ICUs). Data on organisms from blood cultures obtained from the respective wards between 2005 and 2009 were analyzed. Compared with the adult ICUs, the NICU had a higher frequency of Enterobacteriacae and lower frequencies of typical hospital-acquired pathogens (eg, Klebsiella pneumoniae, 17.4% vs 10.0% [P < .001]; Acinetobacter baumannii, 3.9% vs 11.6% [P < .001]). Antibiotic resistance of gram-negative organisms was also significantly lower in the NICU, including resistance to imipenem (5.7% vs 32.1%; P < .001), amikacin (8.8% vs 30.3%), and ceftriaxone (36.1% vs 74.6%; P < .001). This could possibly be due to the ward-tailored antibiotic policy adopted by the NICU but not by the other ICUs.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacology
  13. De Soir S, Parée H, Kamarudin NHN, Wagemans J, Lavigne R, Braem A, et al.
    Microbiol Spectr, 2024 Jan 11;12(1):e0321923.
    PMID: 38084971 DOI: 10.1128/spectrum.03219-23
    Biofilm-related infections are among the most difficult-to-treat infections in all fields of medicine due to their antibiotic tolerance and persistent character. In the field of orthopedics, these biofilms often lead to therapeutic failure of medical implantable devices and urgently need novel treatment strategies. This forthcoming article aims to explore the dynamic interplay between newly isolated bacteriophages and routinely used antibiotics and clearly indicates synergetic patterns when used as a dual treatment modality. Biofilms were drastically more reduced when both active agents were combined, thereby providing additional evidence that phage-antibiotic combinations lead to synergism and could potentially improve clinical outcome for affected patients.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacology
  14. Kamada T, Vairappan CS
    Nat Prod Commun, 2013 Mar;8(3):287-8.
    PMID: 23678792
    A Bomean red algal population of Laurencia similis Nam et Saito was analyzed for its secondary metabolite composition. Seven compounds were identified: ent-1(10)-aristolen-9beta-ol (1), (+)-aristolone (2), axinysone B (3), 9-aristolen-1alpha-ol (4), 2,3,5,6-tetrabromoindole (5), 1-methyl-2,3,5,6-tetrabromoindole (6), and 1-methyl-2,3,5-tribromoindole (7). Compound 1 was identified as a new optical isomer of 1(10)-aristolen-9beta-ol. Compounds 1, 4 and 5 exhibited good antibacterial activity against antibiotic resistant clinical bacteria and cytotoxic effects against selected cancer cell lines.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacology*
  15. Ishii T, Kamada T, Vairappan CS
    J Asian Nat Prod Res, 2016 May;18(5):415-22.
    PMID: 26983053 DOI: 10.1080/10286020.2016.1145670
    Three new cembranoid diterpenes, 10-hydroxy-nephthenol acetate (1), 7,8-epoxy-10-hydroxy-nephthenol acetate (2), and 6-acetoxy-7,8-epoxy-10-hydroxy-nephthenol acetate (3), along with a known compound, 6-acetoxy-7,8-epoxy-nephthenol acetate (4), were isolated from the Bornean soft coral Nephthea sp. Antibacterial and anticancer activities were exhibited by compounds 1 and 2 against Staphylococcus aureus (ATCC 6538)/Escherichia coli (ATCC 13311) and Hela/MCF-7, respectively.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacology*
  16. Vairappan CS
    Biomol. Eng., 2003 Jul;20(4-6):255-9.
    PMID: 12919806
    Red algae genus Laurencia (Rhodomelaceae, Ceramiales) are known to produce a wide range of chemically interesting secondary halogenated metabolites. This investigation delves upon extraction, isolation, structural elucidation and antibacterial activity of inherently available secondary metabolites of Laurencia majuscula Harvey collected from two locations in waters of Sabah, Malaysia. Two major halogenated compounds, identified as elatol (1) and iso-obtusol (2) were isolated. Structures of these compounds were determined from their spectroscopic data such as IR, 1H-NMR, 13C-NMR and optical rotation. Antibacterial bioassay against human pathogenic bacteria was conducted using disc diffusion (Kirby-Bauer) method. Elatol (1) inhibited six species of bacteria, with significant antibacterial activities against Staphylococcus epidermis, Klebsiella pneumonia and Salmonella sp. while iso-obtusol (2) exhibited antibacterial activity against four bacterial species with significant activity against K. pneumonia and Salmonella sp. Elatol (1) showed equal and better antibacterial activity compared with tested commercial antibiotics while iso-obtusol (2) only equaled the potency of commercial antibiotics against K. pneumonia and Salmonella sp. Further tests conducted using dilution method showed both compounds as having bacteriostatic mode of action against the tested bacteria.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacology
  17. Phan CS, Kamada T, Vairappan CS
    Nat Prod Res, 2020 Apr;34(7):1008-1013.
    PMID: 30600714 DOI: 10.1080/14786419.2018.1543681
    Two new C15-acetogenins, 4-epi-isolaurallene (1) and 4-epi-itomanallene A (2) were isolated from a population of marine red alga Laurencia nangii Masuda from Carrington Reef. The structures of these compounds were determined intensively by NMR and HRESIMS data. Their configurations were elucidated by detailed comparison of chemical shifts, germinal protons splitting and NOE correlations with known and synthesized analogues. In addition, antibacterial activities of these compounds were evaluated. These compounds would serve as diastereomeric models for future reference. Since the isolaurallene, neolaurallene, 9-acetoxy-1,10,12-tribromo-4,7:6,13-bisepoxypentadeca-1,2-diene, itomanallene A and laurendecumallene A were isolated, compounds 1 and 2 were the sixth example of C15-acetogenin with dioxabicyclo[7.3.0]dodecene skeleton.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacology
  18. Phan CS, Kamada T, Kobayashi K, Hamada T, Vairappan CS
    Nat Prod Res, 2018 Jan;32(2):202-207.
    PMID: 28691521 DOI: 10.1080/14786419.2017.1346638
    A new xenicane diterpenoid, 15-deoxy-isoxeniolide-A (1) along with four known compounds 9-deoxy-isoxeniolide-A (2), isoxeniolide-A (3), xeniolide-A (4) and coraxeniolide-B (5) were isolated from the Bornean soft coral Xenia sp. The structures of these metabolites were elucidated on the basis of spectral analysis, NMR and HRESIMS. Compound 5 showed cytotoxic activity against ATL cell line, S1T.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacology*
  19. Kamada T, Phan CS, Vairappan CS
    Nat Prod Res, 2019 Feb;33(4):464-471.
    PMID: 29092618 DOI: 10.1080/14786419.2017.1396593
    Three new halogenated tricyclic sesquiterpenes, omphalaurediol (1), rhodolaurenones B (2) and C (3) were isolated together with nine known haloganated sesquiterpenes such as rhodolaurenone A (4), rhodolaureol (5), isorhodolaureol (6), (-)-laurencenone D (7), elatol (8), (+)-deschloroelatol (9), cartilagineol (10), (+)-laurencenone B (11) and 2-chloro-3-hydroxy-α-chamigren-9-one (12) from a population of Bornean red algae Laurencia majuscula. The structures of three new metabolites were determined based on their spectroscopic data (IR, 1D and 2D NMR, and MS). These compounds showed antibacterial activity against three human pathogenic bacteria (Escherichia coli, Salmonella typhi and Vibrio cholera).
    Matched MeSH terms: Anti-Bacterial Agents/pharmacology*
  20. Phan CS, Vairappan CS
    Nat Prod Res, 2017 Apr;31(7):742-748.
    PMID: 27750446 DOI: 10.1080/14786419.2016.1241997
    Four new bicyclogermacrenes, capgermacrenes D (1) E (2) F (3) and G (4) were isolated from a population of Bornean soft coral Capnella imbricata. The structures of these metabolites were elucidated based on their nuclear magnetic resonance and high-resolution electrospray ionisation mass spectrometry spectral data. These compounds showed bacteriastatic and bacteriacidal activities against Staphylococcus aureus and methicillin-resistant Staphylococcus aureus.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacology*
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