Displaying publications 1 - 20 of 73 in total

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  1. 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
  2. Gelatin Hydrogels Loaded with Lactoferrin-Functionalized Bio-Nanosilver as a Potential Antibacterial and Anti-Biofilm Dressing for Infected Wounds: Synthesis, Characterization, and Deciphering of Cytotoxicity
    Suleman Ismail Abdalla S, Katas H, Chan JY, Ganasan P, Azmi F, Fauzi MB
    Mol Pharm, 2021 05 03;18(5):1956-1969.
    PMID: 33822631 DOI: 10.1021/acs.molpharmaceut.0c01033
    Gelatin hydrogels are attractive for wound applications owing to their well-defined structural, physical, and chemical properties as well as good cell adhesion and biocompatibility. This study aimed to develop gelatin hydrogels incorporated with bio-nanosilver functionalized with lactoferrin (Ag-LTF) as a dual-antimicrobial action dressing, to be used in treating infected wounds. The hydrogels were cross-linked using genipin prior to loading with Ag-LTF and characterized for their physical and swelling properties, rheology, polymer and actives interactions, and in vitro release of the actives. The hydrogel's anti-biofilm and antibacterial performances against S. aureus and P. aeruginosa as well as their cytotoxicity effects were assessed in vitro, including primary wound healing gene expression of human dermal fibroblasts (HDFs). The formulated hydrogels showed adequate release of AgNPs and LTF, with promising antimicrobial effects against both bacterial strains. The Ag-LTF-loaded hydrogel did not significantly interfere with the normal cellular functions as no alteration was detected for cell viability, migration rate, and expression of the target genes, suggesting the nontoxicity of Ag-LTF as well as the hydrogels. In conclusion, Ag-LTF-loaded genipin-cross-linked gelatin hydrogel was successfully synthesized as a new approach for fighting biofilms in infected wounds, which may be applied to accelerate healing of chronic wounds.
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects
  3. Betacyanin-inhibited biofilm formation of co-culture of Staphylococcus aureus and Pseudomonas aeruginosa on different polymer surfaces
    Yong YY, Ong MWK, Dykes G, Choo WS
    FEMS Microbiol Lett, 2021 01 26;368(1).
    PMID: 33338235 DOI: 10.1093/femsle/fnaa214
    Staphylococcus aureus and Pseudomonas aeruginosa are bacteria that cause biofilm-associated infections. The aim of this study was to determine the activity of combined betacyanin fractions from Amaranthus dubius (red spinach) and Hylocereus polyrhizus (red pitahaya) against biofilms formed by co-culture of S. aureus and P. aeruginosa on different polymer surfaces. Various formulations containing different concentrations of the betacyanin fractions were investigated for biofilm-inhibiting activity on polystyrene surfaces using crystal violet assay and scanning electron microscopy. A combination of each betacyanin fraction (0.625 mg mL-1) reduced biofilm formation of five S. aureus strains and four P. aeruginosa strains from optical density values of 1.24-3.84 and 1.25-3.52 to 0.81-2.63 and 0.80-1.71, respectively. These combined fractions also significantly inhibited dual-species biofilms by 2.30 and reduced 1.0-1.3 log CFU cm-2 bacterial attachment on polymer surfaces such as polyvinyl chloride, polyethylene, polypropylene and silicone rubber. This study demonstrated an increase in biofilm-inhibiting activity against biofilms formed by two species using combined fractions than that by using single fractions. Betacyanins found in different plants could collectively be used to potentially decrease the risk of biofilm-associated infections caused by these bacteria on hydrophobic polymers.
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects*
  4. 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
  5. 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
  6. Novel functional antimicrobial and biocompatible arabinoxylan/guar gum hydrogel for skin wound dressing applications
    Khan MUA, Raza MA, Razak SIA, Abdul Kadir MR, Haider A, Shah SA, et al.
    J Tissue Eng Regen Med, 2020 10;14(10):1488-1501.
    PMID: 32761978 DOI: 10.1002/term.3115
    It is a challenging task to develop active biomacromolecular wound dressing materials that are biocompatible and possesses antibacterial properties against the bacterial strains that cause severe skin disease. This work is focused on the preparation of a biocompatible and degradable hydrogel for wound dressing application using arabinoxylan (ARX) and guar gum (GG) natural polymers. Fourier transform infrared spectroscopy (FT-IR) confirmed that both ARX and GG interacted well with each other, and their interactions further increased with the addition of crosslinker tetraethyl orthosilicate. Scanning electron microscope (SEM) micrographs showed uniform porous morphologies of the hydrogels. The porous morphologies and uniform interconnected pores are attributed to the increased crosslinking of the hydrogel. Elastic modulus, tensile strength, and fracture strain of the hydrogels significantly improved (from ATG-1 to ATG-4) with crosslinking. Degradability tests showed that hydrogels lost maximum weight in 7 days. All the samples showed variation in swelling with pH. Maximum swelling was observed at pH 7. The hydrogel samples showed good antibacterial activity against Pseudomonas aeruginosa (Gram-negative) and Staphylococcus aureus (Gram-positive) in PBS, good drug release profile (92% drug release), and nontoxic cellular behavior. The cells not only retained their cylindrical morphologies onto the hydrogel but were also performing their normal activities. It is, therefore, believed that as-developed hydrogel could be a potential material for wound dressing application.
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects
  7. Fulltext Effect of rhamnolipid on the physicochemical properties and interaction of bacteria and fungi
    Hamzah N, Kasmuri N, Tao W, Singhal N, Padhye L, Swift S
    Braz J Microbiol, 2020 Sep;51(3):1317-1326.
    PMID: 32399689 DOI: 10.1007/s42770-020-00295-0
    Bacterial adhesion on surfaces is an essential initial step in promoting bacterial mobilization for soil bioremediation process. Modification of the cell surface is required to improve the adhesion of bacteria. The modification of physicochemical properties by rhamnolipid to Pseudomonas putida KT2442, Rhodococcus erythropolis 3586 and Aspergillus brasiliensis ATCC 16404 strains was analysed using contact angle measurements. The surface energy and total free energy of adhesion were calculated to predict the adhesion of both bacteria strains on the A. brasiliensis surface. The study of bacterial adhesion was carried out to evaluate experimental value with the theoretical results. Bacteria and fungi physicochemical properties were modified significantly when treated with rhamnolipid. The adhesion rate of P. putida improved by 16% with the addition of rhamnolipid (below 1 CMC), while the increase of rhamnolipid concentration beyond 1 CMC did not further enhance the bacterial adhesion. The addition of rhamnolipid did not affect the adhesion of R. erythropolis. A good relationship has been obtained in which water contact angle and surface energy of fungal surfaces are the major factors contributing to the bacterial adhesion. The adhesion is mainly driven by acid-base interaction. This finding provides insight to the role of physicochemical properties in controlling the bacterial adhesion on the fungal surface to enhance bacteria transport in soil bioremediation.
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects*
  8. Fulltext In vitro activity of ceftazidime-avibactam and comparators against Gram-negative bacterial isolates collected in the Asia-Pacific region as part of the INFORM program (2015-2017)
    Ko WC, Stone GG
    Ann Clin Microbiol Antimicrob, 2020 Apr 01;19(1):14.
    PMID: 32238155 DOI: 10.1186/s12941-020-00355-1
    BACKGROUND: Antimicrobial resistance among nosocomial Gram-negative pathogens is a cause for concern in the Asia-Pacific region. The aims of this study were to measure the rates of resistance among clinical isolates collected in Asia-Pacific countries, and to determine the in vitro antimicrobial activities of ceftazidime-avibactam and comparators against these isolates.

    METHODS: CLSI broth microdilution methodology was used to determine antimicrobial activity and EUCAST breakpoints version 9.0 were used to determine rates of susceptibility and resistance. Isolates were also screened for the genes encoding extended-spectrum β-lactamases (ESBLs) or carbapenemases (including metallo-β-lactamases [MBLs]).

    RESULTS: Between 2015 and 2017, this study collected a total of 7051 Enterobacterales isolates and 2032 Pseudomonas aeruginosa isolates from hospitalized patients in Australia, Japan, South Korea, Malaysia, the Philippines, Taiwan, and Thailand. In the Asia-Pacific region, Enterobacterales isolates that were ESBL-positive, carbapenemase-negative (17.9%) were more frequently identified than isolates that were carbapenemase-positive, MBL-negative (0.7%) or carbapenemase-positive, MBL-positive (1.7%). Multidrug-resistant (MDR) isolates of P. aeruginosa were more commonly identified (23.4%) than isolates that were ESBL-positive, carbapenemase-negative (0.4%), or carbapenemase-positive, MBL-negative (0.3%), or carbapenemase-positive, MBL-positive (3.7%). More than 90% of all Enterobacterales isolates, including the ESBL-positive, carbapenemase-negative subset and the carbapenemase-positive, MBL-negative subset, were susceptible to amikacin and ceftazidime-avibactam. Among the carbapenemase-positive, MBL-positive subset of Enterobacterales, susceptibility to the majority of agents was reduced, with the exception of colistin (93.4%). Tigecycline was active against all resistant subsets of the Enterobacterales (MIC90, 1-4 mg/L) and among Escherichia coli isolates, > 90% from each resistant subset were susceptible to tigecycline. More than 99% of all P. aeruginosa isolates, including MDR isolates and the carbapenemase-positive, MBL-positive subset, were susceptible to colistin.

    CONCLUSIONS: In this study, amikacin, ceftazidime-avibactam, colistin and tigecycline appear to be potential treatment options for infections caused by Gram-negative pathogens in the Asia-Pacific region.

    Matched MeSH terms: Pseudomonas aeruginosa/drug effects*
  9. Fulltext The role of hospital environment in transmissions of multidrug-resistant gram-negative organisms
    Chia PY, Sengupta S, Kukreja A, S L Ponnampalavanar S, Ng OT, Marimuthu K
    Antimicrob Resist Infect Control, 2020 02 11;9(1):29.
    PMID: 32046775 DOI: 10.1186/s13756-020-0685-1
    Infections by multidrug-resistant (MDR) Gram-negative organisms (GN) are associated with a high mortality rate and present an increasing challenge to the healthcare system worldwide. In recent years, increasing evidence supports the association between the healthcare environment and transmission of MDRGN to patients and healthcare workers. To better understand the role of the environment in transmission and acquisition of MDRGN, we conducted a utilitarian review based on literature published from 2014 until 2019.
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects
  10. Identification of Antibacterial Molecule(s) from Animals Living in Polluted Environments
    Winnie FYM, Siddiqui R, Sagathevan K, Khan NA
    Curr Pharm Biotechnol, 2020;21(5):425-437.
    PMID: 31577204 DOI: 10.2174/1389201020666191002153435
    BACKGROUND: Snakes feed on germ-infested rodents, while water monitor lizards thrive on rotten matter in unhygienic conditions. We hypothesize that such creatures survive the assault of superbugs and are able to fend off disease by producing antimicrobial substances. In this study, we investigated the potential antibacterial activity of sera/lysates of animals living in polluted environments.

    METHODS: Snake (Reticulatus malayanus), rats (Rattus rattus), water monitor lizard (Varanus salvator), frog (Lithobates catesbeianus), fish (Oreochromis mossambicus), chicken (Gallus gallus domesticus), and pigeon (Columba livia) were dissected and their organ lysates/sera were collected. Crude extracts were tested for bactericidal effects against neuropathogenic E. coli K1, methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pyogenes, Pseudomonas aeruginosa, Bacillus cereus and Klebsiella pneumoniae. To determine whether lysates/sera protect human cells against bacterialmediated damage, cytotoxicity assays were performed by measuring lactate dehydrogenase release as an indicator of cell death. Lysates/sera were partially characterized using heat-treatment and pronasetreatment and peptide sequences were determined using the Liquid Chromatography Mass Spectrometry (LC-MS).

    RESULTS: Snake and water monitor lizard sera exhibited potent broad-spectrum bactericidal effects against all bacteria tested. Heat inactivation and pronase-treatment inhibited bactericidal effects indicating that activity is heat-labile and pronase-sensitive suggesting that active molecules are proteinaceous in nature. LCMS analyses revealed the molecular identities of peptides.

    CONCLUSION: The results revealed that python that feeds on germ-infested rodents and water monitor lizards that feed on rotten organic waste possess antibacterial activity in a heat-sensitive manner and several peptides were identified. We hope that the discovery of antibacterial activity in the sera of animals living in polluted environments will stimulate research in finding antibacterial agents from unusual sources as this has the potential for the development of novel strategies in the control of infectious diseases.

    Matched MeSH terms: Pseudomonas aeruginosa/drug effects
  11. Application of Phenotype Microarray for Profiling Carbon Sources Utilization between Biofilm and Non-Biofilm of Pseudomonas aeruginosa from Clinical Isolates
    Ismail NS, Subbiah SK, Taib NM
    Curr Pharm Biotechnol, 2020;21(14):1539-1550.
    PMID: 32598252 DOI: 10.2174/1389201021666200629145217
    BACKGROUND: This is the fastest work in obtaining the metabolic profiles of Pseudomonas aeruginosa in order to combat the infection diseases which leads to high morbidity and mortality rates. Pseudomonas aeruginosa is a high versatility of gram-negative bacteria that can undergo aerobic and anaerobic respiration. Capabilities in deploying different carbon sources, energy metabolism and regulatory system, ensure the survival of this microorganism in the diverse environment condition. Determination of differences in carbon sources utilization among biofilm and non-biofilm of Pseudomonas aeruginosa provides a platform in understanding the metabolic activity of the microorganism.

    METHODS: The study was carried out from September 2017 to February 2019. Four archive isolates forming strong and intermediate biofilm and non-biofilms producer were subcultured from archive isolates. ATCC 27853 P. aeruginosa was used as a negative control or non-biofilm producing microorganism. Biofilm formation was confirmed by Crystal Violet Assay (CVA) and Congo Red Agar (CRA). Metabolic profiles of the biofilm and non-biofilms isolates were determined by phenotype microarrays (Biolog Omnilog).

    RESULTS AND DISCUSSION: In this study, Pseudomonas aeruginosa biofilm isolates utilized uridine, L-threonine and L-serine while non-biofilm utilized adenosine, inosine, monomethyl, sorbic acid and succinamic acid.

    CONCLUSION: The outcome of this result will be used for future studies to improve detection or inhibit the growth of P. aeruginosa biofilm and non-biofilm respectively.

    Matched MeSH terms: Pseudomonas aeruginosa/drug effects
  12. 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
  13. Black sea cucumber (Holothuria atra Jaeger, 1833) rescues Pseudomonas aeruginosa-infected Caenorhabditis elegans via reduction of pathogen virulence factors and enhancement of host immunity
    Lee WT, Tan BK, Eng SA, Yuen GC, Chan KL, Sim YK, et al.
    Food Funct, 2019 Sep 01;10(9):5759-5767.
    PMID: 31453615 DOI: 10.1039/c9fo01357a
    A strategy to circumvent the problem of multidrug resistant pathogens is the discovery of anti-infectives targeting bacterial virulence or host immunity. Black sea cucumber (Holothuria atra) is a tropical sea cucumber species traditionally consumed as a remedy for many ailments. There is a paucity of knowledge on the anti-infective capacity of H. atra and the underlying mechanisms involved. The objective of this study is to utilize the Caenorhabditis elegans-P. aeruginosa infection model to elucidate the anti-infective properties of H. atra. A bioactive H. atra extract and subsequently its fraction were shown to have the capability of promoting the survival of C. elegans during a customarily lethal P. aeruginosa infection. The same entities also attenuate the production of elastase, protease, pyocyanin and biofilm in P. aeruginosa. The treatment of infected transgenic lys-7::GFP worms with this H. atra fraction restores the repressed expression of the defense enzyme lys-7, indicating an improved host immunity. QTOF-LCMS analysis revealed the presence of aspidospermatidine, an indole alkaloid, and inosine in this fraction. Collectively, our findings show that H. atra possesses anti-infective properties against P. aeruginosa infection, by inhibiting pathogen virulence and, eventually, reinstating host lys-7 expression.
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects*
  14. Sodium carboxymethyl cellulose hydrogels containing reduced graphene oxide (rGO) as a functional antibiofilm wound dressing
    Ali NH, Amin MCIM, Ng SF
    J Biomater Sci Polym Ed, 2019 06;30(8):629-645.
    PMID: 30896336 DOI: 10.1080/09205063.2019.1595892
    Biofilms comprise bacteria attached to wound surfaces and are major contributors to non-healing wounds. It was found that the increased resistance of biofilms to antibiotics allows wound infections to persist chronically in spite of antibiotic therapy. In this study, the reduced form of graphene oxide (rGO) was explored as plausible antibiofilm agents. The rGO was synthesized via reducing the functional groups of GO. Then, rGO were characterized using zetasizer, X-ray photoelectron spectroscopy, UV-Vis spectroscopy and FESEM. The rGO were then formulated into sodium carboxymethyl cellulose (NaCMC) hydrogels to form rGO hydrogel and tested for antibiofilm activities in vitro using XTT test, and in vivo biofilm formation assay using nematodes C. elegans. Reduced GO hydrogel was successfully formed by reducing the functional groups of GO, and a reduction of up to 95% of functional groups was confirmed with X-ray photoelectron spectroscopy analysis. XTT tests confirmed that rGO hydrogels reduced biofilm formation by S. aureus (81-84%) and P. aeruginosa (50-62%). Fluorescence intensity also confirmed that rGO hydrogel can inhibit biofilm bacteria in C. elegans experiments. This study implied that rGO hydrogel is an effective antibiofilm agent for infected wounds.
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects
  15. Changing drug resistance profile in Pseudomonas aeruginosa infection among HIV patients from 2010-2017: A retrospective study
    Swathirajan CR, Rameshkumar MR, Solomon SS, Vignesh R, Balakrishnan P
    J Glob Antimicrob Resist, 2019 03;16:274-277.
    PMID: 30389636 DOI: 10.1016/j.jgar.2018.10.019
    OBJECTIVES: Pseudomonas aeruginosa is an important aetiological agent causing pneumonia, urinary tract infections and bacteraemia. High antibiotic use in nosocomial settings and for immunocompromised conditions results in increasing multidrug resistance. This study analysed the antimicrobial resistance profile of P. aeruginosa isolates in an HIV setting.

    METHODS: A total of 7386 clinical specimens were collected from HIV patients attending YRG CARE from 2010-2017. P. aeruginosa isolated from clinical specimens were identified conventionally, and antimicrobial susceptibility testing was performed by the Kirby-Bauer disk diffusion method.

    RESULTS: A total of 260 P. aeruginosa strains were isolated, with 165 P. aeruginosa (63.5%) being isolated from hospitalised patients. A higher incidence of P. aeruginosa infection (25.8%) was observed in 2017, and most of the P. aeruginosa were isolated from sputum specimens (57.3%). A high level of resistance was noted to ceftazidime (49.6%), followed by ticarcillin (41.5%). Imipenem and meropenem resistance was observed in 15.0% and 16.9% of P. aeruginosa isolates, respectively. A high rate of imipenem resistance was noted in 2016 (46.2%) and a high rate of meropenem resistance was noted in 2017 (20.5%). An increasing resistance rate of P. aeruginosa was observed against aztreonam, cefepime, levofloxacin, meropenem, piperacillin, piperacillin/tazobactam, ticarcillin and tobramycin from 2010 to 2017.

    CONCLUSION: A constant increase in drug-resistant P. aeruginosa isolates from HIV patients was observed from 2010 to 2017. Findings from this study urge the need for periodical monitoring and surveillance of the P. aeruginosa resistance profile, especially in hospitalised and immunocompromised patients in resource-limited settings.

    Matched MeSH terms: Pseudomonas aeruginosa/drug effects*
  16. Biofilm inhibiting activity of betacyanins from red pitahaya (Hylocereus polyrhizus) and red spinach (Amaranthus dubius) against Staphylococcus aureus and Pseudomonas aeruginosa biofilms
    Yong YY, Dykes G, Lee SM, Choo WS
    J Appl Microbiol, 2019 Jan;126(1):68-78.
    PMID: 30153380 DOI: 10.1111/jam.14091
    AIMS: To investigate the biofilm inhibitory activity of betacyanins from red pitahaya (Hylocereus polyrhizus) and red spinach (Amaranthus dubius) against Staphylococcus aureus and Pseudomonas aeruginosa biofilms.

    METHODS AND RESULTS: The pulp of red pitahaya and the leaves of red spinach were extracted using methanol followed by subfractionation to obtain betacyanin fraction. The anti-biofilm activity was examined using broth microdilution assay on polystyrene surfaces and expressed as minimum biofilm inhibitory concentration (MBIC). The betacyanin fraction from red spinach showed better anti-biofilm activity (MBIC: 0·313-1·25 mg ml-1 ) against five Staph. aureus strains while the betacyanin fraction from red pitahaya showed better anti-biofilm activity (MBIC: 0·313-0·625 mg ml-1 ) against four P. aeruginosa strains. Both betacyanin fraction significantly reduced hydrophobicity of Staph. aureus and P. aeruginosa strains. Numbers of Staph. aureus and P. aeruginosa attached to polystyrene were also reduced without affecting their cell viability.

    CONCLUSION: Betacyanins can act as anti-biofilm agents against the initial step of biofilm formation, particularly on a hydrophobic surface like polystyrene.

    SIGNIFICANCE AND IMPACT OF THE STUDY: This study is the first to investigate the use of betacyanin as a biofilm inhibitory agent. Betacyanin could potentially be used to reduce the risk of biofilm-associated infections.

    Matched MeSH terms: Pseudomonas aeruginosa/drug effects*
  17. Molecular Characterization of Extended-Spectrum Beta Lactamase- and Carbapenemase-Producing Pseudomonas aeruginosa Strains from a Malaysian Tertiary Hospital
    Phoon HYP, Hussin H, Hussain BM, Thong KL
    Microb Drug Resist, 2018 Oct;24(8):1108-1116.
    PMID: 29437541 DOI: 10.1089/mdr.2017.0258
    Pseudomonas aeruginosa infections account for high morbidity and mortality rates worldwide. Increasing resistance toward β-lactams, especially carbapenems, poses a serious therapeutic challenge. However, the multilocus sequence typing (MLST) of extended-spectrum beta lactamase (ESBL)- and carbapenemase-producing clinical P. aeruginosa has not been reported in Malaysia. This study aimed to determine the antibiotic susceptibility profiles, resistance genes, pulsotypes, and sequence types (STs) of clinical P. aeruginosa from a Malaysian tertiary hospital. These characteristics were analyzed by disk diffusion, minimum inhibitory concentration, polymerase chain reaction, pulsed-field gel electrophoresis (PFGE), and MLST for 199 nonreplicate clinical strains. The susceptibility of the strains toward the carbapenems and piperacillin-tazobactam was the lowest (≤90%), while ≥90% of the strains remained susceptible to all other classes of antimicrobial agents tested. The multidrug-resistant strains displayed high level resistance to cephalosporins (48 to ≥256 mg/L) and carbapenems (4-32 mg/L). Eleven strains harbored class 1 integrons containing blaGES-13, blaVIM-2, blaVIM-6, blaOXA-10, aacA(6')-Ib, aacA(6')-II, aadA6, and gcuD gene cassettes. Extra-integron genes, blaGES-20, blaIMP-4, blaVIM-2, and blaVIM-11, were also found. Overall, the maximum likelihood tree showed concordance in the clustering of strains having the same STs and PFGE clusters. ST708 was the predominant antibiotic-susceptible clone detected from the neonatal intensive care unit. The STs 235, 809, and 1076 clonal clusters consisted of multidrug resistant strains. ST235 is a recognized international high-risk clone. This is the first report of blaGES-13 and blaGES-20 ESBL-encoding gene variants and novel STs (STs 2329, 2335, 2337, 2338, 2340, and 2341) of P. aeruginosa in Malaysia.
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects
  18. Detection of VIM-2-, IMP-1- and NDM-1-producing multidrug-resistant Pseudomonas aeruginosa in Malaysia
    Liew SM, Rajasekaram G, Puthucheary SD, Chua KH
    J Glob Antimicrob Resist, 2018 06;13:271-273.
    PMID: 29432937 DOI: 10.1016/j.jgar.2018.01.026
    OBJECTIVES: The increasing incidence of carbapenem-resistant Pseudomonas aeruginosa along with the discovery of novel metallo-β-lactamases (MBLs) is of concern. In this study, the isolation of MBL-producing P. aeruginosa clinical strains in Malaysia was investigated.

    METHODS: A total of 53 P. aeruginosa clinical strains were isolated from different patients in Sultanah Aminah Hospital (Johor Bahru, Malaysia) in 2015. Antimicrobial susceptibility testing was performed, and minimum inhibitory concentrations (MICs) of imipenem and meropenem were determined by Etest. Carbapenem-resistant strains were screened for MBL production by the imipenem-ethylene diamine tetra-acetic acid (IMP-EDTA) double-disk synergy test, MBL imipenem/imipenem-inhibitor (IP/IPI) Etest and PCR. Multilocus sequence typing (MLST) analysis was performed for genotyping of the isolates.

    RESULTS: Among the 53 clinical strains, 3 (5.7%) were identified as MBL-producers. Multidrug resistance was observed in all three strains, and two were resistant to all of the antimicrobials tested. Sequencing analysis confirmed that the three strains harboured carbapenemase genes (blaIMP-1, blaVIM-2 and blaNDM-1 in one isolate each). These multidrug-resistant strains were identified as sequence type 235 (ST235) and ST308.

    CONCLUSIONS: The blaIMP-1 and blaNDM-1 genes have not previously been reported in Malaysian P. aeruginosa isolates. The emergence of imipenemase 1 (IMP-1)- and New Delhi metallo-β-lactamase 1 (NDM-1)-producing P. aeruginosa in Malaysia maybe travel-associated.

    Matched MeSH terms: Pseudomonas aeruginosa/drug effects*
  19. Fulltext The Effects of Chinese Herbal Medicines on the Quorum Sensing-Regulated Virulence in Pseudomonas aeruginosa PAO1
    Chong YM, How KY, Yin WF, Chan KG
    Molecules, 2018 04 21;23(4).
    PMID: 29690523 DOI: 10.3390/molecules23040972
    The quorum sensing (QS) system has been used by many opportunistic pathogenic bacteria to coordinate their virulence determinants in relation to cell-population density. As antibiotic-resistant bacteria are on the rise, interference with QS has been regarded as a novel way to control bacterial infections. As such, many plant-based natural products have been widely explored for their therapeutic roles. These natural products may contain anti-QS compounds that could block QS signals generation or transmission to combat QS pathogens. In this study, we report the anti-QS activities of four different Chinese herbal plant extracts: Poria cum Radix pini, Angelica dahurica, Rhizoma cibotii and Schizonepeta tenuifolia, on Pseudomonas aeruginosa PAO1. All the plants extracted using hexane, chloroform and methanol were tested and found to impair swarming motility and pyocyanin production in P.aeruginosa PAO1, particularly by Poria cum Radix pini. In addition, all the plant extracts also inhibited violacein production in C.violaceum CV026 up to 50% while bioluminescence activities were reduced in lux-based E. coli biosensors, pSB401 and pSB1075, up to about 57%. These anti-QS properties of the four medicinal plants are the first documentation that demonstrates a potential approach to attenuate pathogens’ virulence determinants.
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects*
  20. Fulltext Probiotic Properties of Exopolysaccharide-Producing Lactobacillus Strains Isolated from Tempoyak
    Khalil ES, Abd Manap MY, Mustafa S, Alhelli AM, Shokryazdan P
    Molecules, 2018 Feb 13;23(2).
    PMID: 29438288 DOI: 10.3390/molecules23020398
    Tempoyak is a functional Malaysian food (an acid-fermented condiment) which is produced from the pulp of the durian (Durio zibethinus) fruit. The current study aimed to isolate and identify potential exopolysaccharide (EPS)-producing Lactobacillus strains from tempoyak for potential use as probiotics. Seven isolates (DUR2, DUR4, DUR5, DUR8, DUR12, DUR18, and DUR20) out of 44 were able to produce EPS, and exhibited resistance to acid and bile salt compared to the reference strains Lactobacillus rhmnosus (ATCC53103) and L. plantarum (ATCC8014). The seven isolated strains belonged to five different species-L. plantarum, L. fermentum, L. crispatus, L. reuteri, and L. pentosus-which were identified using API 50 CHL and 16S rRNA gene sequences (Polymerase chain reaction, PCR - based). The seven strains displayed different ability to produce EPS (100-850 mg/L). Isolates exhibited a high survivability to acid (pH 3.0), bile salts (0.3%), and gastrointestinal tract model (<70%). Results showed that the auto-aggregation and cell surface hydrophobicity ranged from 39.98% to 60.09% and 50.80% to 80.53%, respectively, whereas, the highest co-aggregation value (66.44%) was observed by L. fermentum (DUR8) with Pseudomonas aeruginosa. The isolates showed good inhibitory activity against tested pathogens, high antioxidant activity (32.29% to 73.36%), and good ability to reduce cholesterol (22.55% to 75.15%). Thus, the seven tested strains have value as probiotics.
    Matched MeSH terms: Pseudomonas aeruginosa/drug effects
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