Displaying publications 1 - 20 of 73 in total

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  1. Molecular characterization of Antarctic actinobacteria and screening for antimicrobial metabolite production
    Lee LH, Cheah YK, Mohd Sidik S, Ab Mutalib NS, Tang YL, Lin HP, et al.
    World J Microbiol Biotechnol, 2012 May;28(5):2125-37.
    PMID: 22806035 DOI: 10.1007/s11274-012-1018-1
    The present study aimed to isolate actinobacteria from soil samples and characterized them using molecular tools and screened their secondary metabolites for antimicrobial activities. Thirty-nine strains from four different location of Barrientos Island, Antarctica using 12 types of isolation media was isolated. The isolates were preceded to screening of secondary metabolites for antimicrobial and antifungal activities. Using high-throughput screening methods, 38% (15/39) of isolates produced bioactive metabolites. Approximately 18% (7/39), 18% (7/39), 10% (4/39) and 2.5% (1/39) of isolates inhibited growth of Candida albicans ATCC 10231(T), Staphylococcus aurues ATCC 51650(T), methicillin-resistant Staphylococcus aurues (MRSA) ATCC BAA-44(T) and Pseudomonas aeruginosa ATCC 10145(T), respectively. Molecular characterization techniques like 16S rRNA analysis, Enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR), Random amplified polymorphic DNA (RAPD) and composite analyses were used to characterize the actinobacteria strains. Analysis of 16S rRNA sequences is still one of the most powerful methods to determine higher taxonomic relationships of Actinobacteria. Both RAPD and ERIC-PCR fingerprinting have shown good discriminatory capability but RAPD proved to be better in discriminatory power than ERIC-PCR. Our results demonstrated that composite analysis of both fingerprinting generally increased the discrimination ability and generated best clustering for actinobacteria strains in this study.
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects
  2. Antibacterial activity and morphological changes of Pseudomonas aeruginosa cells after exposure to Vernonia cinerea extract
    Latha LY, Darah I, Kassim MJ, Sasidharan S
    Ultrastruct Pathol, 2010 Aug;34(4):219-25.
    PMID: 20594042 DOI: 10.3109/01913121003651513
    The antibacterial activity of Vernonia cinerea (L.) extract was investigated using the broth dilution method. The extract showed a favorable antimicrobial activity against Pseudomonas aeruginosa with a minimum inhibition concentration (MIC) value of 3.13 mg/mL. V. cinerea extract at (1/2), 1, or 2 times the MIC significantly inhibited bacterial growth with a noticeable drop in optical density (OD) of the bacterial culture, thus confirming the antibacterial activity of the extract on P. aeruginosa. Imaging using scanning (SEM) and transmission (TEM) electron microscopy was done to determine the major alterations in the microstructure of the extract-treated P. aeruginosa. The main abnormalities noted via SEM and TEM studies were the alteration in morphology of the bacterial cells. The main reason for this destruction was the severe alterations of the cell wall with the formation of holes, invaginations, and morphological disorganization caused by the extract. The authors conclude that the extract may be used as a candidate for the development of antimicrobial agents.
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects*
  3. Fulltext Phenotypic detection of metallo-β-lactamase in imipenem-resistant Pseudomonas aeruginosa
    Khosravi Y, Loke MF, Chua EG, Tay ST, Vadivelu J
    ScientificWorldJournal, 2012;2012:654939.
    PMID: 22792048 DOI: 10.1100/2012/654939
    Carbapenems are the primary choice of treatment for severe Pseudomonas aeruginosa infection. However, the emergence of carbapenem resistance due to the production of metallo-β-lactamases (MBLs) is of global concern. In this study, 90 imipenem- (IPM- or IP-) resistant P. aeruginosa (IRPA) isolates, including 32 previously tested positive and genotyped for MBL genes by PCR, were subjected to double-disk synergy test (DDST), combined disk test (CDT), and imipenem/imipenem-inhibitor (IP/IPI) E-test to evaluate their MBLs detection capability. All three methods were shown to have a sensitivity of 100%. However, DDST was the most specific of the three (96.6%), followed by IP/IPI E-test interpreted based on the single criteria of IP/IPI ≥8 as positive (62.1%), and CDT was the least specific (43.1%). Based on the data from this evaluation, we propose that only IRPA with IP MIC >16 μg/mL and IP/IPI ≥8 by IP/IPI E-test should be taken as positive for MBL activity. With the new dual interpretation criteria, the MBL IP/IPI E-test was shown to achieve 100% sensitivity as well as specificity for the IRPA in this study. Therefore, the IP/IPI E-test is a viable alternative phenotypic assay to detect MBL production in IRPA in our population in circumstances where PCR detection is not a feasible option.
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects*
  4. Antimicrobial susceptibility pattern and distribution of exoU and exoS in clinical isolates of Pseudomonas aeruginosa at a Malaysian hospital
    Idris SN, Desa MN, Aziz MN, Taib NM
    Southeast Asian J. Trop. Med. Public Health, 2012 Jan;43(1):116-23.
    PMID: 23082561
    This study was conducted to determine the antibiotic susceptibility pattern and distribution of exoU and exoS among 44 clinical isolates of P. aeruginosa collected from different patients over a 3-month period in 2010 at a major Malaysian hospital. Susceptibility data by disk diffusion method for cefepime (30 microg), ceftazidime (30 microg), gentamicin (10 microg), piperacillin-tazobactam (100/10 microg) and ciprofloxacin (5 microg) were available for 38 isolates. Resistance to ceftazidime and piperacillin-tazobactam was the most common (74%) with five isolates not susceptible to three or more different antibiotics. PCR detection of exoU and exoS of all 44 isolates showed the former gene to be present in 18 and exoS in 41. In analyzing the two genes together, 17 isolates were detected for exoU and exoS with only two being negative for both genes. Only one isolate was detected for exoU alone whereas 24 for exoS alone. Distribution of the genes in relation to antibiotic susceptibility was inapplicable due to the majority of the isolates having similar susceptibility patterns, but the tendency of exoU-carrying isolates to be present in male patients (83%) and respiratory sites (61%) was observed (p < 0.050). The finding warrants further investigation in a larger sample of isolates.\

    Study site: Hospital Kuala Lumpur (HKL)
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects*
  5. In vitro evaluation of the growth enhancing or cytotoxic effect of Sticophus species (Gamat) on established human fibroblast cell lines and antimicrobial activity
    Philip R, Dinsuhaimi S, Rosdan S, Samsudin AR, Shamsuria O, Mohd Zaki S, et al.
    Med J Malaysia, 2004 May;59 Suppl B:95-6.
    PMID: 15468835
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects
  6. Fulltext In vitro activity of sulperazon against recent isolates of ceftazidime-resistant bacteria
    Lim VKE, Halijah MY
    Med J Malaysia, 2001 Sep;56(3):365-9.
    PMID: 11732084
    The in vitro activity of sulperazon (cefoperazone/sulbactam) was tested against 94 ceftazidime-resistant strains of bacteria isolated from mostly seriously ill patients in critical care units. Acinetobacter baumanii, Pseudomonas aeruginosa and Klebsiella pneumoniae made up 80% of the pathogens studied; 90% of the Klebsiella strains were producers of extended-spectrum beta-lactamases (ESBL). The MIC90 of sulperazon for Klebsiella was 12 mg/l (range 1.5-16 mg/l), indicating that this drug may be a useful alternative for the treatment of ceftazidime-resistant, ESBL-producing Klebsiella.
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects
  7. Fulltext In vitro activity of aminoglycosides, ureidopenicillins and cephalosporins against P. aeruginosa isolated in Kuala Lumpur
    Ngeow YS, Puthucheary SD, Lai PS
    Med J Malaysia, 1985 Sep;40(3):196-201.
    PMID: 3939567
    170 clinical isolates of Pseudomonas aeruginosa were tested for in vitro susceptibility to gentamicin, amikacin, tobramycin, netilmicin, kanamycin, streptomycin, cefotaxime, ceftriaxone, cefoperazone, ceftazidime, moxalactam, azlocillin, piperacillin and ticarcillin. Against 93 gentamicin-sensitive strains, the most active antibiotics were in descending order, ceftazidime, tobramycin, gentamicin, amikacin, and the ureidopenicillins. Against 77 gentamicin-resistant strains, only ceftazidime, amikacin and moxalactam had mode minimum inhibitory concentrations within achievable peak serum levels after standard therapeutic dosage. There was no correlation between cephalosporin resistance and aminoglycoside resistance except for cefoperazone, which, together with the ureidopenicillins and ticarcillin, showed marked decrease in activity against gentamicin-resistant strains.
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects*
  8. Fulltext Anti-quorum sensing activity of the traditional Chinese herb, Phyllanthus amarus
    Priya K, Yin WF, Chan KG
    Sensors (Basel), 2013;13(11):14558-69.
    PMID: 24169540 DOI: 10.3390/s131114558
    The discovery of quorum sensing in Proteobacteria and its function in regulating virulence determinants makes it an attractive alternative towards attenuation of bacterial pathogens. In this study, crude extracts of Phyllanthus amarus Schumach. & Thonn, a traditional Chinese herb, were screened for their anti-quorum sensing properties through a series of bioassays. Only the methanolic extract of P. amarus exhibited anti-quorum sensing activity, whereby it interrupted the ability of Chromobacterium violaceum CVO26 to response towards exogenously supplied N-hexanoylhomoserine lactone and the extract reduced bioluminescence in E. coli [pSB401] and E. coli [pSB1075]. In addition to this, methanolic extract of P. amarus significantly inhibited selected quorum sensing-regulated virulence determinants of Pseudomonas aeruginosa PA01. Increasing concentrations of the methanolic extracts of P. amarus reduced swarming motility, pyocyanin production and P. aeruginosa PA01 lecA::lux expression. Our data suggest that P. amarus could be useful for attenuating pathogens and hence, more local traditional herbs should be screened for its anti-quorum sensing properties as their active compounds may serve as promising anti-pathogenic drugs.
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects
  9. Fulltext Caffeine as a potential quorum sensing inhibitor
    Norizan SN, Yin WF, Chan KG
    Sensors (Basel), 2013;13(4):5117-29.
    PMID: 23598500 DOI: 10.3390/s130405117
    Quorum sensing enables bacteria to control the gene expression in response to the cell density. It regulates a variety of bacterial physiological functions such as biofilm formation, bioluminescence, virulence factors and swarming which has been shown contribute to bacterial pathogenesis. The use of quorum sensing inhibitor would be of particular interest in treating bacterial pathogenicity and infections. In this work, we have tested caffeine as quorum sensing inhibitor by using Chromobacterium violaceum CV026 as a biosensor. We verified that caffeine did not degrade the N-acyl homoserine lactones tested. In this work, it is shown that caffeine could inhibit N-acyl homoserine lactone production and swarming of a human opportunistic pathogen, namely Pseudomonas aeruginosa PA01. To the best of our knowledge, this is the first documentation providing evidence on the presence of anti-quorum sensing activity in caffeine. Our work will allow caffeine to be explored as anti-infective drugs.
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects*
  10. Fulltext Piper nigrum, Piper betle and Gnetum gnemon--natural food sources with anti-quorum sensing properties
    Tan LY, Yin WF, Chan KG
    Sensors (Basel), 2013;13(3):3975-85.
    PMID: 23519352 DOI: 10.3390/s130303975
    Various parts of Piper nigrum, Piper betle and Gnetum gnemon are used as food sources by Malaysians. The purpose of this study is to examine the anti-quorum sensing (anti-QS) properties of P. nigrum, P. betle and G. gnemon extracts. The hexane, chloroform and methanol extracts of these plants were assessed in bioassays involving Pseudomonas aeruginosa PA01, Escherichia coli [pSB401], E. coli [pSB1075] and Chromobacterium violaceum CV026. It was found that the extracts of these three plants have anti-QS ability. Interestingly, the hexane, chloroform and methanol extracts from P. betle showed the most potent anti-QS activity as judged by the bioassays. Since there is a variety of plants that serve as food sources in Malaysia that have yet to be tested for anti-QS activity, future work should focus on identification of these plants and isolation of the anti-QS compounds.
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects
  11. Fulltext Inhibition of quorum sensing-controlled virulence factor production in Pseudomonas aeruginosa PAO1 by Ayurveda spice clove (Syzygium aromaticum) bud extract
    Krishnan T, Yin WF, Chan KG
    Sensors (Basel), 2012;12(4):4016-30.
    PMID: 22666015 DOI: 10.3390/s120404016
    Quorum sensing controls the virulence determinants in most proteobacteria. In this work, the hexane, chloroform and methanol extracts of an Ayurveda spice, namely clove (Syzygium aromaticum), shown anti-quorum sensing activity. Hexane and methanol extracts of clove inhibited the response of C. violaceum CV026 to exogenously supplied N-hexanoylhomoserine lactone, in turn preventing violacein production. Chloroform and methanol extracts of clove significantly reduced bioluminescence production by E. coli [pSB1075] grown in the presence of N-(3-oxododecanoyl)-L-homoserine lactone. We demonstrated that clove extract inhibited quorum sensing-regulated phenotypes in Pseudomonas aeruginosa PA01, including expression of lecA::lux (by hexane extract), swarming (maximum inhibition by methanol extract), pyocyanin (maximum inhibition by hexane extract). This study shows that the presence of natural compounds that exhibit anti-quorum sensing activity in the clove extracts may be useful as the lead of anti-infective drugs.
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects
  12. Fulltext Non-antibiotic quorum sensing inhibitors acting against N-acyl homoserine lactone synthase as druggable target
    Chang CY, Krishnan T, Wang H, Chen Y, Yin WF, Chong YM, et al.
    Sci Rep, 2014;4:7245.
    PMID: 25430794 DOI: 10.1038/srep07245
    N-acylhomoserine lactone (AHL)-based quorum sensing (QS) is important for the regulation of proteobacterial virulence determinants. Thus, the inhibition of AHL synthases offers non-antibiotics-based therapeutic potentials against QS-mediated bacterial infections. In this work, functional AHL synthases of Pseudomonas aeruginosa LasI and RhlI were heterologously expressed in an AHL-negative Escherichia coli followed by assessments on their AHLs production using AHL biosensors and high resolution liquid chromatography-mass spectrometry (LCMS). These AHL-producing E. coli served as tools for screening AHL synthase inhibitors. Based on a campaign of screening synthetic molecules and natural products using our approach, three strongest inhibitors namely are salicylic acid, tannic acid and trans-cinnamaldehyde have been identified. LCMS analysis further confirmed tannic acid and trans-cinnemaldehyde efficiently inhibited AHL production by RhlI. We further demonstrated the application of trans-cinnemaldehyde inhibiting Rhl QS system regulated pyocyanin production in P. aeruginosa up to 42.06%. Molecular docking analysis suggested that trans-cinnemaldehyde binds to the LasI and EsaI with known structures mainly interacting with their substrate binding sites. Our data suggested a new class of QS-inhibiting agents from natural products targeting AHL synthase and provided a potential approach for facilitating the discovery of anti-QS signal synthesis as basis of novel anti-infective approach.
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects
  13. Fulltext Gut bacteria of Cuora amboinensis (turtle) produce broad-spectrum antibacterial molecules
    Akbar N, Khan NA, Sagathevan K, Iqbal M, Tawab A, Siddiqui R
    Sci Rep, 2019 11 18;9(1):17012.
    PMID: 31740685 DOI: 10.1038/s41598-019-52738-w
    Antimicrobial resistance is a major threat to human health, hence there is an urgent need to discover antibacterial molecule(s). Previously, we hypothesized that microbial gut flora of animals are a potential source of antibacterial molecules. Among various animals, Cuora amboinensis (turtle) represents an important reptile species living in diverse ecological environments and feed on organic waste and terrestrial organisms and have been used in folk medicine. The purpose of this study was to mine turtle's gut bacteria for potential antibacterial molecule(s). Several bacteria were isolated from the turtle gut and their conditioned media were prepared. Conditioned media showed potent antibacterial activity against several Gram-positive (Bacillus cereus, Streptococcus pyogenes and methicillin-resistant Staphylococcus aureus) and Gram-negative (neuropathogenic Escherichia coli K1, Serratia marcescens, Pseudomonas aeruginosa, Salmonella enterica and Klebsiella pneumoniae) pathogenic bacteria. Conditioned media-mediated bactericidal activity was heat-resistant when treated at 95°C for 10 min. By measuring Lactate dehydrogenase release, the results showed that conditioned media had no effect on human cell viability. Tandem Mass Spectrometric analysis revealed the presence of various secondary metabolites, i.e., a series of known as well as novel N-acyl-homoserine lactones, several homologues of 4-hydroxy-2-alkylquinolines, and rhamnolipids, which are the signature metabolites of Pseudomonas species. These findings are significant and provide the basis for rational development of therapeutic interventions against bacterial infections.
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects
  14. Fulltext A scaffolded approach to unearth potential antibacterial components from epicarp of Malaysian Nephelium lappaceum L
    Asghar A, Tan YC, Zahoor M, Zainal Abidin SA, Yow YY, Khan E, et al.
    Sci Rep, 2021 Jul 05;11(1):13859.
    PMID: 34226594 DOI: 10.1038/s41598-021-92622-0
    The emergence and spread of antimicrobial resistance have been of serious concern to human health and the management of bacterial infectious diseases. Effective treatment of these diseases requires the development of novel therapeutics, preferably free of side effects. In this regard, natural products are frequently conceived to be potential alternative sources for novel antibacterial compounds. Herein, we have evaluated the antibacterial activity of the epicarp extracts of the Malaysian cultivar of yellow rambutan fruit (Nephelium lappaceum L.) against six pathogens namely, Bacillus subtilis, methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pyogenes, Pseudomonas aeruginosa, Klebsiella pneumoniae and Salmonella enterica. Among a series of solvent extracts, fractions of ethyl acetate and acetone have revealed significant activity towards all tested strains. Chemical profiling of these fractions, via HPLC, LC-MS and GC-MS, has generated a library of potentially bioactive compounds. Downstream virtual screening, pharmacological prediction, and receptor-ligand molecular dynamics simulation have eventually unveiled novel potential antibacterial compounds, which can be extracted for medicinal use. We report compounds like catechin, eplerenone and oritin-4-beta-ol to be computationally inhibiting the ATP-binding domain of the chaperone, DnaK of P. aeruginosa and MRSA. Thus, our work follows the objective to propose new antimicrobials capable of perforating the barrier of resistance posed by both the gram positives and the negatives.
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects
  15. Fulltext Prodigiosin inhibits bacterial growth and virulence factors as a potential physiological response to interspecies competition
    Yip CH, Mahalingam S, Wan KL, Nathan S
    PLoS One, 2021;16(6):e0253445.
    PMID: 34161391 DOI: 10.1371/journal.pone.0253445
    Prodigiosin, a red linear tripyrrole pigment, has long been recognised for its antimicrobial property. However, the physiological contribution of prodigiosin to the survival of its producing hosts still remains undefined. Hence, the aim of this study was to investigate the biological role of prodigiosin from Serratia marcescens, particularly in microbial competition through its antimicrobial activity, towards the growth and secreted virulence factors of four clinical pathogenic bacteria (methicillin-resistant Staphylococcus aureus (MRSA), Enterococcus faecalis, Salmonella enterica serovar Typhimurium and Pseudomonas aeruginosa) as well as Staphylococcus aureus and Escherichia coli. Prodigiosin was first extracted from S. marcescens and its purity confirmed by absorption spectrum, high performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrophotometry (LC-MS/MS). The extracted prodigiosin was antagonistic towards all the tested bacteria. A disc-diffusion assay showed that prodigiosin is more selective towards Gram-positive bacteria and inhibited the growth of MRSA, S. aureus and E. faecalis and Gram-negative E. coli. A minimum inhibitory concentration of 10 μg/μL of prodigiosin was required to inhibit the growth of S. aureus, E. coli and E. faecalis whereas > 10 μg/μL was required to inhibit MRSA growth. We further assessed the effect of prodigiosin towards bacterial virulence factors such as haemolysin and production of protease as well as on biofilm formation. Prodigiosin did not inhibit haemolysis activity of clinically associated bacteria but was able to reduce protease activity for MRSA, E. coli and E. faecalis as well as decrease E. faecalis, Salmonella Typhimurium and E. coli biofilm formation. Results of this study show that in addition to its role in inhibiting bacterial growth, prodigiosin also inhibits the bacterial virulence factor protease production and biofilm formation, two strategies employed by bacteria in response to microbial competition. As clinical pathogens were more resistant to prodigiosin, we propose that prodigiosin is physiologically important for S. marcescens to compete against other bacteria in its natural soil and surface water environments.
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects
  16. Fulltext Next generation sequencing reveals the antibiotic resistant variants in the genome of Pseudomonas aeruginosa
    Ramanathan B, Jindal HM, Le CF, Gudimella R, Anwar A, Razali R, et al.
    PLoS One, 2017;12(8):e0182524.
    PMID: 28797043 DOI: 10.1371/journal.pone.0182524
    Rapid progress in next generation sequencing and allied computational tools have aided in identification of single nucleotide variants in genomes of several organisms. In the present study, we have investigated single nucleotide polymorphism (SNP) in ten multi-antibiotic resistant Pseudomonas aeruginosa clinical isolates. All the draft genomes were submitted to Rapid Annotations using Subsystems Technology (RAST) web server and the predicted protein sequences were used for comparison. Non-synonymous single nucleotide polymorphism (nsSNP) found in the clinical isolates compared to the reference genome (PAO1), and the comparison of nsSNPs between antibiotic resistant and susceptible clinical isolates revealed insights into the genome variation. These nsSNPs identified in the multi-drug resistant clinical isolates were found to be altering a single amino acid in several antibiotic resistant genes. We found mutations in genes encoding efflux pump systems, cell wall, DNA replication and genes involved in repair mechanism. In addition, nucleotide deletions in the genome and mutations leading to generation of stop codons were also observed in the antibiotic resistant clinical isolates. Next generation sequencing is a powerful tool to compare the whole genomes and analyse the single base pair variations found within the antibiotic resistant genes. We identified specific mutations within antibiotic resistant genes compared to the susceptible strain of the same bacterial species and these findings may provide insights to understand the role of single nucleotide variants in antibiotic resistance.
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects
  17. Sweetening Inhaled Antibiotic Treatment for Eradication of Chronic Respiratory Biofilm Infection
    Loo CY, Lee WH, Lauretani G, Scalia S, Cipolla D, Traini D, et al.
    Pharm Res, 2018 Feb 07;35(3):50.
    PMID: 29417313 DOI: 10.1007/s11095-018-2350-4
    PURPOSE: The failure of chronic therapy with antibiotics to clear persistent respiratory infection is the key morbidity and mortality factor for patients with chronic lung diseases, primarily due to the presence of biofilm in the lungs. It is hypothesised that carbon sources, such as mannitol, could stimulate the metabolic activity of persister cells within biofilms and restore their susceptibility to antibiotics. The aims of the current study are to: (1) establish a representative in vitro model of Pseudomonas aeruginosa biofilm lung infection, and (2) investigate the effects of nebulised mannitol on antibiotic efficacy, focusing on ciprofloxacin, in the eradication of biofilm.

    METHOD: Air interface biofilm was cultured onto Snapwell inserts incorporated into a modified pharmacopeia deposition apparatus, the Anderson Cascade Impactor (ACI). Three different formulations including mannitol only, ciprofloxacin only and combined ciprofloxacin and mannitol were nebulised onto the P. aeruginosa biofilm using the modified ACI. Antibacterial effectiveness was evaluated using colony-forming units counts, biofilm penetration and scanning electron microscopy.

    RESULTS: Nebulised mannitol promotes the dispersion of bacteria from the biofilm and demonstrated a synergistic enhancement of the antibacterial efficacy of ciprofloxacin compared to delivery of antibiotic alone.

    CONCLUSIONS: The combination of ciprofloxacin and mannitol may provide an important new strategy to improve antibiotic therapy for the treatment of chronic lung infections. Furthermore, the development of a representative lung model of bacterial biofilm could potentially be used as a platform for future new antimicrobial pre-clinical screening.

    Matched MeSH terms: Pseudomonas aeruginosa/drug effects*
  18. Antibacterial activity in vitro of Thymus capitatus from Jordan
    Qaralleh HN, Abboud MM, Khleifat KM, Tarawneh KA, Althunibat OY
    Pak J Pharm Sci, 2009 Jul;22(3):247-51.
    PMID: 19553168
    This study was carried out to evaluate the antibacterial activity of aqueous and organic extracts of Thymus capitatus L. (Lamiaceae) leaves and stems. Dried ground powder leaves and stems were extracted with water (aqueous extracts), ethanol, dichloromethane and hexane (Soxhlet extracts). The antibacterial activity of these extracts was evaluated against bacteria using disc diffusion method. The result obtained showed that the leaves had stronger antibacterial activity than the stems extracts. The ethanolic extract had the highest yield products and the high antibacterial activity than all other solvents. The results suggest that essential oil as non-polar organic compounds could be the main active compounds in this plant. Therefore the antibacterial activity of leaves ethanol extracts (LEE) was compared with essential oils leaves extracts (LEO) of T. capitatus. The LEO showed greater antibacterial activity than LEE. The LEO showed a broad spectrum of antibacterial activity and the Pseudomonas aeruginosa was the most sensitive bacteria.
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects
  19. Synthesis, spectral analysis and biological evaluation of 2-{[(morpholin-4-yl)ethyl]thio}-5-phenyl/aryl-1,3,4-oxadiazole derivatives
    Ur-Rehman A, Khan SG, Naqvi SAR, Ahmad M, Akhtar N, Bokhari TH, et al.
    Pak J Pharm Sci, 2021 Jan;34(1(Special)):441-446.
    PMID: 34275792
    A series of new derivatives of 4-(2-chloroethyl)morpholine hydrochloride (5) were efficiently synthesized. Briefly, different aromatic organic acids (1a-f) were refluxed to acquire respective esters (2a-f) using conc. H2SO4 as catalyst. The esters were subjected to nucleophillic substitution by monohydrated hydrazine to acquire hydrazides (3a-f). The hydrazides were cyclized with CS2 in the presence of KOH to yield corresponding oxadiazoles (4a-f). Finally, the derivatives, 6a-f, were prepared by reacting oxadiazoles (4a-f) with 5 using NaH as activator. Structures of all the derivatives were elucidated through 1D-NMR EI-MS and IR spectral data. All these molecules were subjected to antibacterial and hemolytic activities and showed good antibacterial and hemolytic potential relative to the reference standards.
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects
  20. In vitro antimicrobial activity against Pseudomonas aeruginosa and acute oral toxicity of marine algae Gracilaria changii
    Sasidharan S, Darah I, Noordin MK
    N Biotechnol, 2010 Sep 30;27(4):390-6.
    PMID: 20170762 DOI: 10.1016/j.nbt.2010.02.002
    Methanol extract of the Gracilaria changii has been screened for antimicrobial activity against Pseudomonas aeruginosa. Antimicrobial activities were carried out using disc diffusion assay and broth dilution method against P. aeruginosa. The methanol extract of G. changii showed a good antimicrobial activity against P. aeruginosa with MIC (Minimum Inhibitory Concentration) value of 6.25mg/ml. Exposure of P. aeruginosa cells to 6.25mg/ml of methanol extract of G. changii resulted in complete inhibition of the bacterial cells. The main abnormalities noted via SEM and TEM studies were the alterations in morphology and cytology of the bacterial cells. The main reason for this deterioration was discussed. The effect of the methanol extract on the growth profile for the bacteria was also done and confirmed the bactericidal effect of the G. changii methanol extract on P. aeruginosa by changing the normal growth profile of P. aeruginosa. In an acute toxicity study using mice, the median lethal dose (LD(50)) of the extract was greater than 2000 mg/kg, and we found no pathological changes in macroscopic examination by necropsy of mice treated with extract. We conclude that G. changii might be safely used as an antimicrobial agent.
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects*
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