Displaying publications 181 - 200 of 332 in total

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  1. Microplastics in Sediment Cores from Asia and Africa as Indicators of Temporal Trends in Plastic Pollution
    Matsuguma Y, Takada H, Kumata H, Kanke H, Sakurai S, Suzuki T, et al.
    Arch Environ Contam Toxicol, 2017 Aug;73(2):230-239.
    PMID: 28534067 DOI: 10.1007/s00244-017-0414-9
    Microplastics (<5 mm) were extracted from sediment cores collected in Japan, Thailand, Malaysia, and South Africa by density separation after hydrogen peroxide treatment to remove biofilms were and identified using FTIR. Carbonyl and vinyl indices were used to avoid counting biopolymers as plastics. Microplastics composed of variety of polymers, including polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethyleneterphthalates (PET), polyethylene-polypropylene copolymer (PEP), and polyacrylates (PAK), were identified in the sediment. We measured microplastics between 315 µm and 5 mm, most of which were in the range 315 µm-1 mm. The abundance of microplastics in surface sediment varied from 100 pieces/kg-dry sediment in a core collected in the Gulf of Thailand to 1900 pieces/kg-dry sediment in a core collected in a canal in Tokyo Bay. A far higher stock of PE and PP composed microplastics in sediment compared with surface water samples collected in a canal in Tokyo Bay suggests that sediment is an important sink for microplastics. In dated sediment cores from Japan, microplastic pollution started in 1950s, and their abundance increased markedly toward the surface layer (i.e., 2000s). In all sediment cores from Japan, Thailand, Malaysia, and South Africa, the abundance of microplastics increased toward the surface, suggesting the global occurrence of and an increase in microplastic pollution over time.
    Matched MeSH terms: Biofilms
  2. Fulltext Quaternary ammonium silane (k21) based intracanal medicament triggers biofilm destruction
    Kok ESK, Lim XJ, Chew SX, Ong SF, See LY, Lim SH, et al.
    BMC Oral Health, 2021 03 12;21(1):116.
    PMID: 33711992 DOI: 10.1186/s12903-021-01470-x
    BACKGROUND: Compare antimicrobial efficacy of a quarternary ammonium silane (QAS)/k21 as an intracanal medicament against E. faecalis and C. albicans biofilms formed on root dentin.

    METHODOLOGY: Dentin blocks were sterilized and E. faecalis and C. albicans microbial colonies were counted for colony-forming-units against 2%k21, 2%CHX and Ca(OH)2 medicaments. Biofilm colonies after 7 days on dentin were analysed using confocal laser scanning microscopy with live/dead bacterial viability staining. TEM was done to study dentin collagen matrix. Dentin discs from 3rd day and 7th day well plate was used for Raman spectra and observed under fluorescent-microscope. Docking studies were carried out on MMP-2 S1 binding-domain with k21.

    RESULTS: There was reduction of E. faecalis/C. albicans when k21, chlorhexidine and calcium hydroxide were used with highest percentage in 2%k21 treated specimens. 2%k21 showed dense and regular collagen network with intact cross-banding and decreased Raman intensity for 2%k21 on 3rd day. NaOCl + k21 showed least adherence, whereas saline groups showed highest adherence of E. faecalis and C. albicans to root-canal dentin. Alizarin red staining of hDPSCs revealed calcium deposition in all groups with significant difference seen amongst 2%k21 groups. MMP-2 ligand binding was seen accurately indicating possible target sites for k21 intervention.

    CONCLUSION: 2%k21 can be considered as alternative intracanal medicament.

    Matched MeSH terms: Biofilms
  3. Surface engineered iron oxide nanoparticles as efficient materials for antibiofilm application
    Velusamy P, Su CH, Kannan K, Kumar GV, Anbu P, Gopinath SCB
    Biotechnol Appl Biochem, 2021 Mar 10.
    PMID: 33751641 DOI: 10.1002/bab.2146
    Overuse of antibiotics has led to the development of multi drug resistant strains. Antibiotic resistance is a major drawback in the biomedical field since medical implants are prone to infection by biofilms of antibiotic resistant strains of bacteria. With increasing prevalence of antibiotic resistant pathogenic bacteria, the search for alternative method is utmost importance. In this regard, magnetic nanoparticles are commonly used as a substitute for antibiotics that can circumvent the problem of biofilms growth on the surface of biomedical implants. Iron oxide nanoparticles (IONPs) have unique magnetic properties that can be exploited in various ways in the biomedical applications. IONPs are engineered employing different methods to induce surface functionalization that include the use of polyethyleneimine and oleic acid. IONPs have a mechanical effect on biofilms when in presence of an external magnet. In this review, a detailed description of surface engineered magnetic nanoparticles as ideal antibacterial agents is provided, accompanied by various methods of literature review. This article is protected by copyright. All rights reserved.
    Matched MeSH terms: Biofilms
  4. The antimicrobial and antibiofilm properties of allicin against Candida albicans and Staphylococcus aureus - A therapeutic potential for denture stomatitis
    Zainal M, Mohamad Zain N, Mohd Amin I, Ahmad VN
    Saudi Dent J, 2021 Feb;33(2):105-111.
    PMID: 33551624 DOI: 10.1016/j.sdentj.2020.01.008
    The objective of this study is to determine the therapeutic efficacy of allicin against Candida albicans (C. albicans) and Staphylococcus aureus (S. aureus), the common etiological agents for denture stomatitis (DS). The minimum inhibitory concentration (MICs), minimum bactericidal concentrations (MBCs) and minimum fungicidal concentration (MFCs) of allicin were determined by the broth microdilution method followed by checkerboard microdilution method for a synergistic interaction between allicin + nystatin and allicin + CHX. The potential of allicin to eradicate C. albicans and S. aureus biofilms was assessed by treating biofilm formed on self- polymerized acrylic resin with allicin at a sub-MIC concentration for 5 min. The commercial denture cleanser (brand X) was used as a positive control. A Kruskal-Wallis test followed by the post-hoc Mann-Whitney U test was applied (SPSS 20.0), and the level of significance was set at P 
    Matched MeSH terms: Biofilms
  5. Nano-enabled strategies to combat methicillin-resistant Staphylococcus aureus
    Singh S, Numan A, Somaily HH, Gorain B, Ranjan S, Rilla K, et al.
    Mater Sci Eng C Mater Biol Appl, 2021 Oct;129:112384.
    PMID: 34579903 DOI: 10.1016/j.msec.2021.112384
    The emergence of methicillin-resistant Staphylococcus aureus (MRSA) has become a threat to global health because of limited treatments. MRSA infections are difficult to treat due to increasingly developing resistance in combination with protective biofilms of Staphylococcus aureus (S. aureus). Nanotechnology-based research revealed that effective MRSA treatments could be achieved through targeted nanoparticles (NPs) that withstand biological films and drug resistance. Thus, the principal aim towards improving MRSA treatment is to advance drug delivery tools, which successfully address the delivery-related problems. These potential delivery tools would also carry drugs to the desired sites of therapeutic action to overcome the adverse effects. This review focused on different types of nano-engineered carriers system for antimicrobial agents with improved therapeutic efficacy of entrapped drugs. The structural characteristics that play an essential role in the effectiveness of delivery systems have also been addressed with a description of recent scientific advances in antimicrobial treatment, emphasizing challenges in MRSA treatments. Consequently, existing gaps in the literature are highlighted, and reported contradictions are identified, allowing for the development of roadmaps for future research.
    Matched MeSH terms: Biofilms
  6. Fulltext The efficacy of honey-cinnamon commixture in diabetic wound healing. [Abstract]
    Azib FN, Lee CH, Mohd Yusof NM, Yusuf N, Mohd Fuad NF, Saharuddin NS, et al.
    Malaysian Journal of Medicine and Health Sciences, 2020;16(105):23-0.
    MyJurnal
    1st UMS INTERNATIONAL NURSING CONFERENCE IN CONJUNCTION WITH 11TH INTERNATIONAL NURSING STUDENTS’ FORUM
    A view into the future of nursing: Nursing Transformation towards IR-4.0, Held at the Faculty of Medicine and Health Sciences,, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia, On 6-8th March 2020
    Introduction: Delayed wound healing and a hefty cost of treatment poses a burden to those undergoing treatment for Diabetic wound care. An alternative wound product to speed up wound healing may address this problem. Honey has been recognized around the world for its efficacy as treating wounds, eczema, and inflammation while cinnamon has a variety of biological functions including anti-diabetic, anti-microbial, and anti-inflammatory. As both cinnamon and honey possess different properties in wound healing, it is hypothesized that combining both products can accelerate wound healing. This study is to compare the efficacy of pure honey, pure cinnamon and honey-cinnamon commixture in diabetic wound healing.
    Methods: Three volunteers were selected from Kitamura clinic, Pontianak, Indonesia participated in this study. Each of them was given a different wound product which were pure honey (subject 1), pure cinnamon extract (subject 2), and honey-cinnamon commixture (subject 3). The wound bed percentage, size, and characteristics were recorded and compared. Results: Usage of pure cinnamon was discontinued during the second visit due to its drying effect. Subjects 1 and 3 both presented with an increase in granulation and reduction in sloughing of cells and biofilm. However, subject 3 showed faster wound contraction and reduction in maceration as compared to subject 1.
    Conclusion: Pure cinnamon extract should not be used as a standalone wound product due to its drying properties. However, topical co-administration of honey and Cinnamon cassia extract has a synergistic interaction effect, improves wound healing in diabetic individuals and is recommended as a new topical herbal drug production for treating of the diabetic wound. Further studies on the therapeutic concentration of honey-cinnamon commixture should be conducted.
    Matched MeSH terms: Biofilms
  7. Fulltext Green Synthesis and Characterization of Silver Nanoparticles Using Spondias mombin Extract and Their Antimicrobial Activity against Biofilm-Producing Bacteria
    Samuggam S, Chinni SV, Mutusamy P, Gopinath SCB, Anbu P, Venugopal V, et al.
    Molecules, 2021 May 03;26(9).
    PMID: 34063685 DOI: 10.3390/molecules26092681
    Multidrug resistant bacteria create a challenging situation for society to treat infections. Multidrug resistance (MDR) is the reason for biofilm bacteria to cause chronic infection. Plant-based nanoparticles could be an alternative solution as potential drug candidates against these MDR bacteria, as many plants are well known for their antimicrobial activity against pathogenic microorganisms. Spondias mombin is a traditional plant which has already been used for medicinal purposes as every part of this plant has been proven to have its own medicinal values. In this research, the S. mombin extract was used to synthesise AgNPs. The synthesized AgNPs were characterized and further tested for their antibacterial, reactive oxygen species and cytotoxicity properties. The characterization results showed the synthesized AgNPs to be between 8 to 50 nm with -11.52 of zeta potential value. The existence of the silver element in the AgNPs was confirmed with the peaks obtained in the EDX spectrometry. Significant antibacterial activity was observed against selected biofilm-forming pathogenic bacteria. The cytotoxicity study with A. salina revealed the LC50 of synthesized AgNPs was at 0.81 mg/mL. Based on the ROS quantification, it was suggested that the ROS production, due to the interaction of AgNP with different bacterial cells, causes structural changes of the cell. This proves that the synthesized AgNPs could be an effective drug against multidrug resistant bacteria.
    Matched MeSH terms: Biofilms
  8. Fulltext Pseudomonas Aeruginosa and Streptococcus Pyogenes Exposed to Malaysian Trigona Honey In Vitro Demonstrated Downregulation of Virulence Factor
    A Al-Kafaween M, Mohd Hilmi AB, A Nagi Al-Jamal H, A Elsahoryi N, Jaffar N, Khairi Zahri M
    Iran J Biotechnol, 2020 Oct;18(4):e2542.
    PMID: 34056021 DOI: 10.30498/IJB.2020.2542
    Background: Honey has been known as a traditional medicine for centuries with its antibacterial properties. It is considered one of the most enduring substances used in wound management.

    Objectives: This study aimed to: (i) evaluate the effects of Malaysian Trigona honey on bacterial structure and (ii) assess the anti-virulence potential of this honey by examining their impacts on the expression of selected genes (involved in stress survival and biofilm formation) in a test organism.

    Materials and Methods: Trigona honey's impacts on the bacterial structure (cell morphology) and the expression profiles of select Pseudomonas Aeruginosa and Streptococcus Pyogenes genes were examined using scanning electron microscopy (SEM) and real-time PCR (RT-qPCR) analysis, respectively.

    Results: SEM showed that the decreased cell density deformed, disrupted, and damaged cells for both bacteria. RT-qPCR showed that the expression of fleN, fleQ, and fleR genes of P.aeruginosa were decreased, 4.26-fold, 3.80-fold and 2.66- fold respectively. In addition, scpA, ftsY, and emm13 of S.pyogenes were decreased, 2.87-fold, 3.24-fold, and 4.65-fold respectively.

    Conclusion: Our results indicate that Trigona honey may be an effective inhibitor and virulence modulator of P. aeruginosa and S. pyogenes via multiple molecular targets. This deduction needs to be investigated in vivo.

    Matched MeSH terms: Biofilms
  9. Performance evaluation of a granular activated carbon-sequencing batch biofilm reactor pilot plant system used in treating real wastewater from recycled paper industry
    Muhamad MH, Sheikh Abdullah SR, Mohamad AB, Rahman RA, Kadhum AA
    Environ Technol, 2012 Apr-May;33(7-9):915-26.
    PMID: 22720416
    A pilot scale granular activated carbon-sequencing batch biofilm reactor with a capacity of 2.2 m3 was operated for over three months to evaluate its performance treating real recycled paper industry wastewater under different operational conditions. In this study, dissolved air floatation (DAF) and clarifier effluents were used as influent sources of the pilot plant. During the course of the study, the reactor was able to biodegrade the contaminants in the incoming recycled paper mill wastewater in terms of chemical oxygen demand (COD), adsorbable organic halides (AOX; specifically 2,4-dichlorophenol (2,4-DCP)) and ammoniacal nitrogen (NH3-N) removal efficiencies at varying hydraulic retention times (HRTs) of 1-3 days, aeration rates (ARs) of 2.1-3.4 m3/min and influent feed concentration of 40-950 mg COD/l. Percentages of COD, 2,4-DCP and NH3-N removals increased with increasing HRT, resulting in more than 90% COD, 2,4-DCP and NH3-N removals at HRT values above two days. Degradation of COD, 2,4-DCP and NH3-N were seriously affected by variation of ARs, which resulted in significant decrease of COD, 2,4-DCP and NH3-N removals by decreasing ARs from 3.4 m3/min to 2.1 m3/min, varying in the ranges of 24-80%, 6-96% and 5-42%, respectively. In comparison to the clarifier effluent, the treatment performance of DAF effluent, containing high COD concentration, resulted in a higher COD removal of 82%. The use of diluted DAF effluent did not improve significantly the COD removal. Higher NH3-N removal efficiency of almost 100% was observed during operation after maintenance shutdown compared to normal operation, even at the same HRT of one day due to the higher dissolved oxygen concentrations (1-7 mg/l), while no significant difference in COD removal efficiency was observed.
    Matched MeSH terms: Biofilms
  10. Modeling of crude oil biodegradation using two phase partitioning bioreactor
    Fakhru'l-Razi A, Peyda M, Ab Karim Ghani WA, Abidin ZZ, Zakaria MP, Moeini H
    Biotechnol Prog, 2014 Jul-Aug;30(4):797-805.
    PMID: 24692323 DOI: 10.1002/btpr.1911
    In this work, crude oil biodegradation has been optimized in a solid-liquid two phase partitioning bioreactor (TPPB) by applying a response surface methodology based d-optimal design. Three key factors including phase ratio, substrate concentration in solid organic phase, and sodium chloride concentration in aqueous phase were taken as independent variables, while the efficiency of the biodegradation of absorbed crude oil on polymer beads was considered to be the dependent variable. Commercial thermoplastic polyurethane (Desmopan®) was used as the solid phase in the TPPB. The designed experiments were carried out batch wise using a mixed acclimatized bacterial consortium. Optimum combinations of key factors with a statistically significant cubic model were used to maximize biodegradation in the TPPB. The validity of the model was successfully verified by the good agreement between the model-predicted and experimental results. When applying the optimum parameters, gas chromatography-mass spectrometry showed a significant reduction in n-alkanes and low molecular weight polycyclic aromatic hydrocarbons. This consequently highlights the practical applicability of TPPB in crude oil biodegradation.
    Matched MeSH terms: Biofilms
  11. Immunotherapies for the prevention and treatment of Staphylococcus aureus infections: updates and challenges
    Chung PY
    Pathog Dis, 2023 Jan 17;81.
    PMID: 37422444 DOI: 10.1093/femspd/ftad016
    Staphylococcus aureus is the leading cause of hospital-acquired infections and can cause a wide range of diseases from mild skin infections to invasive diseases including deep surgical site infections, life-threatening bacteremia, and sepsis. This pathogen remains a challenge to manage due to its ability to rapidly develop resistance to antibiotic treatment and to form biofilms. Despite the current infection control measures which involve mainly antibiotics, the burden of infection remains high. The 'omics' approaches have not led to the discovery of novel antibacterials at a pace sufficient to cope with the emergence of multidrug-resistant and biofilm-forming S. aureus, Hence, new strategies for anti-infective therapies need to be explored urgently. One promising strategy is harnessing the immune response to enhance the protective antimicrobial immunity in the host. This review discusses the potential of monoclonal antibodies and vaccines as alternatives to treat and manage infections caused by planktonic and biofilms of S. aureus.
    Matched MeSH terms: Biofilms
  12. Assessment of the factors contributing to the variations in microcystins biodegradability of the biofilms on a practical biological treatment facility
    Li J, Shimizu K, Akasako H, Lu Z, Akiyama S, Goto M, et al.
    Bioresour Technol, 2015 Jan;175:463-72.
    PMID: 25459856 DOI: 10.1016/j.biortech.2014.10.047
    This study revealed the biotic and abiotic parameters driving the variations in microcystins (MCs) biodegradability of a practical biological treatment facility (BTF). Results showed that similar trends of seasonal variation were seen for microcystin-LR (MCLR) biodegradability of biofilms on the BTF and indigenous MCLR-degrader population, where both peaks co-occurred in October, following the peaks of natural MCLR concentration and water temperature observed in August. The lag period might be required for accumulation of MCLR-degraders and MCLR-degrading enzyme activity. The MCLR-degrader population was correlated to temperature, MCLR and chlorophyll-a concentration in water where the biofilms submerged, indicating that these abiotic and biotic parameters exerted direct and/or indirect influences on seasonal variation in MCLR-biodegradability. In comparison, no effect of other co-existing MCs on biodegradation of one MC was observed. However, proliferation of MC-degraders along biodegradation processes positively responded to total amount of MCs, suggesting that multiple MCs contributed additively to MC-degrader proliferation.
    Matched MeSH terms: Biofilms
  13. Fulltext Microbiota organization is a distinct feature of proximal colorectal cancers
    Dejea CM, Wick EC, Hechenbleikner EM, White JR, Mark Welch JL, Rossetti BJ, et al.
    Proc Natl Acad Sci U S A, 2014 Dec 23;111(51):18321-6.
    PMID: 25489084 DOI: 10.1073/pnas.1406199111
    Environmental factors clearly affect colorectal cancer (CRC) incidence, but the mechanisms through which these factors function are unknown. One prime candidate is an altered colonic microbiota. Here we show that the mucosal microbiota organization is a critical factor associated with a subset of CRC. We identified invasive polymicrobial bacterial biofilms (bacterial aggregates), structures previously associated with nonmalignant intestinal pathology, nearly universally (89%) on right-sided tumors (13 of 15 CRCs, 4 of 4 adenomas) but on only 12% of left-sided tumors (2 of 15 CRCs, 0 of 2 adenomas). Surprisingly, patients with biofilm-positive tumors, whether cancers or adenomas, all had biofilms on their tumor-free mucosa far distant from their tumors. Bacterial biofilms were associated with diminished colonic epithelial cell E-cadherin and enhanced epithelial cell IL-6 and Stat3 activation, as well as increased crypt epithelial cell proliferation in normal colon mucosa. High-throughput sequencing revealed no consistent bacterial genus associated with tumors, regardless of biofilm status. However, principal coordinates analysis revealed that biofilm communities on paired normal mucosa, distant from the tumor itself, cluster with tumor microbiomes as opposed to biofilm-negative normal mucosa bacterial communities also from the tumor host. Colon mucosal biofilm detection may predict increased risk for development of sporadic CRC.
    Matched MeSH terms: Biofilms
  14. Fulltext Comparative proteomic analysis of extracellular proteins expressed by various clonal types of Staphylococcus aureus and during planktonic growth and biofilm development
    Atshan SS, Shamsudin MN, Sekawi Z, Thian Lung LT, Barantalab F, Liew YK, et al.
    Front Microbiol, 2015;6:524.
    PMID: 26089817 DOI: 10.3389/fmicb.2015.00524
    Staphylococcus aureus is well known for its biofilm formation with rapid emergence of new clones circulating worldwide. The main objectives of the study were (1) to identify possible differences in protein expression among various and closely related clonal types of S. aureus, (2) to establish the differences in protein expression in terms of size of protein spots and its intensities between bacteria which are grown statically (biofilm formation) with that of under aeration and agitation, and (3) to compare the differences in protein expression as a function of time (in hours). In this study, we selected six clinical isolates comprising two similar (MRSA-527 and MRSA-524) and four different (MRSA-139, MSSA-12E, MSSA-22d, and MSSA-10E) types identified by spa typing, MLST and SCCmec typing. We performed 2D gel migration comparison. Also, two MRSA isolates (527 and 139) were selected to determine quantitative changes in the level of extracellular proteins at different biofilm growth time points of 12, 24, and 48 h. The study was done using a strategy that combines 2-DGE and LC-MS/MS analysis for absolute quantification and identification of the extracellular proteins. The 2DGE revealed that the proteomic profiles for the isolates belonging to the similar spa, MLST, and SCCmec types were still quite different. Among the extracellular proteins secreted at different time points of biofilm formation, significant changes in protein expression were observed at 48 h incubation as compared to the exponential growth at 12 h incubation. The main conclusion of the work is that the authors do observe differences among isolates, and growth conditions do influence the protein content at different time points of biofilm formation.
    Matched MeSH terms: Biofilms
  15. Fulltext Unravelling the genome of long chain N-acylhomoserine lactone-producing Acinetobacter sp. strain GG2 and identification of its quorum sensing synthase gene
    How KY, Hong KW, Sam CK, Koh CL, Yin WF, Chan KG
    Front Microbiol, 2015;6:240.
    PMID: 25926817 DOI: 10.3389/fmicb.2015.00240
    Myriad proteobacteria use N-acyl homoserine lactone (AHL) molecules as quorum sensing (QS) signals to regulate different physiological functions, including virulence, antibiotic production, and biofilm formation. Many of these proteobacteria possess LuxI/LuxR system as the QS mechanism. Recently, we reported the 3.89 Mb genome of Acinetobacter sp. strain GG2. In this work, the genome of this long chain AHL-producing bacterium was unravelled which led to the molecular characterization of luxI homologue, designated as aciI. This 552 bp gene was cloned and overexpressed in Escherichia coli BL21(DE3). The purified protein was ∼20.5 kDa and is highly similar to several autoinducer proteins of LuxI family among Acinetobacter species. To verify the AHL synthesis activity of this protein, high-resolution liquid chromatography-mass spectrometry analysis revealed the production of 3-oxo-dodecanoyl-homoserine lactone and 3-hydroxy-dodecanoyl-homoserine lactone from induced E. coli harboring the recombinant AciI. Our data show for the first time, the cloning and characterization of the luxI homologue from Acinetobacter sp. strain GG2, and confirmation of its AHLs production. These data are of great significance as the annotated genome of strain GG2 has provided a valuable insight in the study of autoinducer molecules and its roles in QS mechanism of the bacterium.
    Matched MeSH terms: Biofilms
  16. Development of biofilm-targeted antimicrobial wound dressing for the treatment of chronic wound infections
    Ng SF, Leow HL
    Drug Dev Ind Pharm, 2015;41(11):1902-9.
    PMID: 25758412 DOI: 10.3109/03639045.2015.1019888
    It has been established that microbial biofilms are largely responsible for the recalcitrance of many wound infections to conventional antibiotics. It was proposed that the efficacy of antibiotics could be optimized via the inhibition of bacterial biofilm growth in wounds. The combination of antibiofilm agent and antibiotics into a wound dressing may be a plausible strategy in wound infection management. Xylitol is an antibiofilm agent that has been shown to inhibit the biofilm formation. The purpose of this study was to develop an alginate film containing xylitol and gentamicin for the treatment of wound infection. Three films, i.e. blank alginate film (SA), alginate film with xylitol (F5) and alginate film with xylitol and gentamicin (AG), were prepared. The films were studied for their physical properties, swelling ratio, moisture absorption, moisture vapor transmission rate (MVTR), mechanical and rheology properties, drug content uniformity as well as in vitro drug release properties. Antimicrobial and antibiofilm in vitro studies on Staphylococcus aureus and Pseudomonas aeruginosa were also performed. The results showed that AG demonstrates superior mechanical properties, rheological properties and a higher MVTR compared with SA and F5. The drug flux of AG was higher than that of commercial gentamicin cream. Furthermore, antimicrobial studies showed that AG is effective against both S. aureus and P. aeruginosa, and the antibiofilm assays demonstrated that the combination was effective against biofilm bacteria. In summary, alginate films containing xylitol and gentamicin may potentially be used as new dressings for the treatment of wound infection.
    Matched MeSH terms: Biofilms
  17. Fulltext Assessment of Antifungal Activity of Bakuchiol on Oral-Associated Candida spp
    Nordin MA, Abdul Razak F, Himratul-Aznita WH
    Evid Based Complement Alternat Med, 2015;2015:918624.
    PMID: 26633986 DOI: 10.1155/2015/918624
    Bakuchiol is an active component of Psoralea glandulosa and Psoralea corylifolia, used in traditional Chinese medicine. The study aimed at investigating the antifungal activity of bakuchiol on planktonic and biofilm forms of orally associated Candida species. The antifungal susceptibility testing was determined by the broth micro dilution technique. Growth kinetics and cell surface hydrophobicity (CSH) of Candida were measured to assess the inhibitory effect of bakuchiol on Candida planktonic cells. Biofilm biomass and cellular metabolic activity were quantitatively estimated by the crystal violet (CV) and the 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide (XTT) assays. All Candida strains have been shown to be susceptible to bakuchiol with the MIC ranges from 12.5 to 100 μg/mL. Significant decrease in specific growth rates and viable counts demonstrates the inhibitory effect of bakuchiol on Candida planktonic cells. A brief exposure to bakuchiol also reduced CSH of Candida (P < 0.05), indicating altered surface properties of yeast cells towards hydrophobic interfaces. Biofilm biomass and cell metabolic activity were mostly decreased, except for C. glabrata (P = 0.29). The antifungal properties of bakuchiol on Candida species in this in vitro study may give insights into the application in therapeutic strategy against Candida infections.
    Matched MeSH terms: Biofilms
  18. RpoS differentially affects the general stress response and biofilm formation in the endophytic Serratia plymuthica G3
    Liu X, Wu Y, Chen Y, Xu F, Halliday N, Gao K, et al.
    Res. Microbiol., 2016 Apr;167(3):168-77.
    PMID: 26671319 DOI: 10.1016/j.resmic.2015.11.003
    The σ(S) subunit RpoS of RNA polymerase functions as a master regulator of the general stress response in Escherichia coli and related bacteria. RpoS has been reported to modulate biocontrol properties in the rhizobacterium Serratia plymuthica IC1270. However, the role of RpoS in the stress response and biofilm formation in S. plymuthica remains largely unknown. Here we studied the role of RpoS from an endophytic S. plymuthica G3 in regulating these phenotypes. Mutational analysis demonstrated that RpoS positively regulates the global stress response to acid or alkaline stresses, oxidative stress, hyperosmolarity, heat shock and carbon starvation, in addition to proteolytic and chitinolytic activities. Interestingly, rpoS mutations resulted in significantly enhanced swimming motility, biofilm formation and production of the plant auxin indole-3-acetic acid (IAA), which may contribute to competitive colonization and environmental fitness for survival. These findings provide further insight into the strain-specific role of RpoS in the endophytic strain G3 of S. plymuthica, where it confers resistance to general stresses encountered within the plant environment. The heterogeneous functionality of RpoS in rhizosphere and endophytic S. plymuthica populations may provide a selective advantage for better adaptation to various physiological and environmental stresses.
    Matched MeSH terms: Biofilms
  19. Fulltext Hypothetical protein Avin_16040 as the S-layer protein of Azotobacter vinelandii and its involvement in plant root surface attachment
    Liew PW, Jong BC, Najimudin N
    Appl Environ Microbiol, 2015 Nov;81(21):7484-95.
    PMID: 26276116 DOI: 10.1128/AEM.02081-15
    A proteomic analysis of a soil-dwelling, plant growth-promoting Azotobacter vinelandii strain showed the presence of a protein encoded by the hypothetical Avin_16040 gene when the bacterial cells were attached to the Oryza sativa root surface. An Avin_16040 deletion mutant demonstrated reduced cellular adherence to the root surface, surface hydrophobicity, and biofilm formation compared to those of the wild type. By atomic force microscopy (AFM) analysis of the cell surface topography, the deletion mutant displayed a cell surface architectural pattern that was different from that of the wild type. Escherichia coli transformed with the wild-type Avin_16040 gene displayed on its cell surface organized motifs which looked like the S-layer monomers of A. vinelandii. The recombinant E. coli also demonstrated enhanced adhesion to the root surface.
    Matched MeSH terms: Biofilms
  20. Fulltext Biosynthesis of Gold Nanoparticles and Its Effect against Pseudomonas aeruginosa
    Ali SG, Jalal M, Ahmad H, Umar K, Ahmad A, Alshammari MB, et al.
    Molecules, 2022 Dec 08;27(24).
    PMID: 36557818 DOI: 10.3390/molecules27248685
    Antimicrobial resistance has posed a serious health concern worldwide, which is mainly due to the excessive use of antibiotics. In this study, gold nanoparticles synthesized from the plant Tinospora cordifolia were used against multidrug-resistant Pseudomonas aeruginosa. The active components involved in the reduction and stabilization of gold nanoparticles were revealed by gas chromatography-mass spectrophotometry(GC-MS) of the stem extract of Tinospora cordifolia. Gold nanoparticles (TG-AuNPs) were effective against P. aeruginosa at different concentrations (50,100, and 150 µg/mL). TG-AuNPs effectively reduced the pyocyanin level by 63.1% in PAO1 and by 68.7% in clinical isolates at 150 µg/mL; similarly, swarming and swimming motilities decreased by 53.1% and 53.8% for PAO1 and 66.6% and 52.8% in clinical isolates, respectively. Biofilm production was also reduced, and at a maximum concentration of 150 µg/mL of TG-AuNPs a 59.09% reduction inPAO1 and 64.7% reduction in clinical isolates were observed. Lower concentrations of TG-AuNPs (100 and 50 µg/mL) also reduced the pyocyanin, biofilm, swarming, and swimming. Phenotypically, the downregulation of exopolysaccharide secretion from P. aeruginosa due to TG-AuNPs was observed on Congo red agar plates.
    Matched MeSH terms: Biofilms
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