Displaying publications 221 - 240 of 326 in total

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  1. Fulltext Genomic analyses of two novel biofilm-degrading methicillin-resistant Staphylococcus aureus phages
    Dakheel KH, Rahim RA, Neela VK, Al-Obaidi JR, Hun TG, Isa MNM, et al.
    BMC Microbiol, 2019 05 28;19(1):114.
    PMID: 31138130 DOI: 10.1186/s12866-019-1484-9
    BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) biofilm producers represent an important etiological agent of many chronic human infections. Antibiotics and host immune responses are largely ineffective against bacteria within biofilms. Alternative actions and novel antimicrobials should be considered. In this context, the use of phages to destroy MRSA biofilms presents an innovative alternative mechanism.

    RESULTS: Twenty-five MRSA biofilm producers were used as substrates to isolate MRSA-specific phages. Despite the difficulties in obtaining an isolate of this phage, two phages (UPMK_1 and UPMK_2) were isolated. Both phages varied in their ability to produce halos around their plaques, host infectivity, one-step growth curves, and electron microscopy features. Furthermore, both phages demonstrated antagonistic infectivity on planktonic cultures. This was validated in an in vitro static biofilm assay (in microtiter-plates), followed by the visualization of the biofilm architecture in situ via confocal laser scanning microscopy before and after phage infection, and further supported by phages genome analysis. The UPMK_1 genome comprised 152,788 bp coding for 155 putative open reading frames (ORFs), and its genome characteristics were between the Myoviridae and Siphoviridae family, though the morphological features confined it more to the Siphoviridae family. The UPMK_2 has 40,955 bp with 62 putative ORFs; morphologically, it presented the features of the Podoviridae though its genome did not show similarity with any of the S. aureus in the Podoviridae family. Both phages possess lytic enzymes that were associated with a high ability to degrade biofilms as shown in the microtiter plate and CLSM analyses.

    CONCLUSIONS: The present work addressed the possibility of using phages as potential biocontrol agents for biofilm-producing MRSA.

    Matched MeSH terms: Biofilms/growth & development*
  2. Fulltext First reported case of Gilbertella persicaria in human stool: outcome of a community study from Segamat, Johor, Malaysia
    Huët MAL, Wong LW, Goh CBS, Ong KS, Dwiyanto J, Reidpath D, et al.
    Braz J Microbiol, 2020 Dec;51(4):2067-2075.
    PMID: 32572838 DOI: 10.1007/s42770-020-00323-z
    Species of fungi belonging to the order Mucorales can be found everywhere in the environment. Gilbertella persicaria, which belongs to this order, have often been isolated from fruits and in water systems. However, there has been no report of isolation of this fungus from human samples. During a gut mycobiome study, from the Segamat community, Gilbertella persicaria was isolated from a human fecal sample and was characterized through a series of morphological assessment, biochemical tests, and molecular techniques. The isolate produced a white velvety surface that turned grayish after 24 h. Although no biofilm production was observed, the results indicated that the isolate could form calcium oxalate crystals, produced urease, and was resistant to low pH. The isolate was sensitive to amphotericin but resistant to voriconazole and itraconazole. The features of this fungus that could help in its survival in the human gut are also discussed.
    Matched MeSH terms: Biofilms/growth & development
  3. Fulltext Colonial morphotypes and biofilm forming ability of Burkholderia pseudomallei
    Koh SF, Tay ST, Puthucheary SD
    Trop Biomed, 2013 Sep;30(3):428-33.
    PMID: 24189672 MyJurnal
    Burkholderia pseudomallei the causative agent of melioidosis, is being increasingly recognized as an important cause of morbidity and mortality in South East Asia. Biofilm formation of B. pseudomallei may be responsible for dormancy, latency and relapse of melioidosis. Based on the colonial morphology of the bacteria on B. pseudomallei selective agar medium, seven distinct morphotypes were identified. This study was conducted to assess the in vitro biofilm produced by B. pseudomallei and to investigate possible correlation between B. pseudomallei morphotypes with biofilm forming abilities of the isolates. Using a standard biofilm crystal violet staining assay, comparison was made between the biofilm forming ability of 76 isolates of B. pseudomallei and Burkholderia thailandensis ATCC 700388. Amongst the blood isolates, 30.2% were considered as high biofilm producers and 27.9% were low producers, 33.3% of the pus isolates were considered as high and 16% low biofilm producers. Most of the isolates were identified as morphotype group 1 which displayed a rough centre with irregular circumference on the agar medium. However, we did not find any correlation of B. pseudomallei morphotypes with biofilm forming abilities (p > 0.05). Additional studies are needed to identify internal and external factors which contribute to the high and low biofilm formation of B. pseudomallei.
    Matched MeSH terms: Biofilms/growth & development*
  4. Fulltext Anti-Candida activity and biofilm inhibitory effects of secreted products of tropical environmental yeasts
    Tan HW, Tay ST
    Trop Biomed, 2011 Apr;28(1):175-80.
    PMID: 21602784
    This study describes the killer phenotypes of tropical environmental yeasts and the inhibition effects of the culture filtrates on the biofilm of Candida albicans. A total of 26 (10.5%) of 258 yeast isolates obtained from an environmental sampling study demonstrated killer activity to Candida species. The killer yeasts were identified as species belonging to the genus Aureobasidium, Pseudozyma, Ustilago and Candida based on sequence analysis of the ITS1-5.8S-ITS2 region of the yeasts. Pseudozyma showed the broadest killing effects against sensitive strains of Candida. New species of Ustilago and Pseudozyma demonstrating killer phenotypes were identified in this study. Interestingly, more than 50% reduction in the metabolic activity of Candida albicans biofilm was noted after exposure to the culture filtrates of the nine killer yeasts. Purification and characterization of toxin and metabolites are essential for understanding the yeast killing effects.
    Matched MeSH terms: Biofilms/drug effects*
  5. An overview of Acinetobacter baumannii pathogenesis: Motility, adherence and biofilm formation
    Mea HJ, Yong PVC, Wong EH
    Microbiol Res, 2021 Jun;247:126722.
    PMID: 33618061 DOI: 10.1016/j.micres.2021.126722
    The Gram-negative opportunistic pathogen Acinetobacter baumannii has gain notoriety in recent decades, primarily due to its propensity to cause nosocomial infections in critically ill patients. Its global spread, multi-drug resistance features and plethora of virulence factors make it a serious threat to public health worldwide. Though much effort has been expended in uncovering its successes, it continues to confound researchers due to its highly adaptive nature, mutating to meet the needs of a given environment. Its persistence in the clinical setting allows it to be in close proximity to a potential host, where contact can be made facilitating infection and colonization. In this article, we aim to provide a current overview of the bacterial virulence factors, specifically focusing on factors involved in the initial stages of infection, highlighting the role of adaptation facilitated by two-component systems and biofilm formation. Finally, the study of host-pathogen interactions using available animal models, their suitability, notable findings and some perspectives moving forward are also discussed.
    Matched MeSH terms: Biofilms/growth & development*
  6. Fulltext Efficient Synthesis of Novel Pyridine-Based Derivatives via Suzuki Cross-Coupling Reaction of Commercially Available 5-Bromo-2-methylpyridin-3-amine: Quantum Mechanical Investigations and Biological Activities
    Ahmad G, Rasool N, Ikram HM, Gul Khan S, Mahmood T, Ayub K, et al.
    Molecules, 2017 Jan 27;22(2).
    PMID: 28134790 DOI: 10.3390/molecules22020190
    The present study describes palladium-catalyzed one pot Suzuki cross-coupling reaction to synthesize a series of novel pyridine derivatives 2a-2i, 4a-4i. In brief, Suzuki cross-coupling reaction of 5-bromo-2-methylpyridin-3-amine (1) directly or via N-[5-bromo-2-methylpyridine-3-yl]acetamide (3) with several arylboronic acids produced these novel pyridine derivatives in moderate to good yield. Density functional theory (DFT) studies were carried out for the pyridine derivatives 2a-2i and 4a-4i by using B3LYP/6-31G(d,p) basis with the help of GAUSSIAN 09 suite programme. The frontier molecular orbitals analysis, reactivity indices, molecular electrostatic potential and dipole measurements with the help of DFT methods, described the possible reaction pathways and potential candidates as chiral dopants for liquid crystals. The anti-thrombolytic, biofilm inhibition and haemolytic activities of pyridine derivatives were also investigated. In particular, the compound 4b exhibited the highest percentage lysis value (41.32%) against clot formation in human blood among all newly synthesized compounds. In addition, the compound 4f was found to be the most potent against Escherichia coli with an inhibition value of 91.95%. The rest of the pyridine derivatives displayed moderate biological activities.
    Matched MeSH terms: Biofilms/drug effects
  7. Plant-derived Compounds as Potential Source of Novel Anti-Biofilm Agents Against Pseudomonas aeruginosa
    Chung PY
    Curr Drug Targets, 2017;18(4):414-420.
    PMID: 27758704 DOI: 10.2174/1389450117666161019102025
    Pseudomonas aeruginosa is the most common Gram-negative bacterium associated with nosocomial and life-threatening chronic infections in cystic fibrosis patients. This pathogen is wellknown for its ability to attach to surfaces of indwelling medical devices to form biofilms, which consist of a regular array of extracellular polymers. Tenaciously bound to the surface of devices and inherently resilient to antibiotic treatment, P. aeruginosa poses a serious threat in clinical medicine and contributes to the persistence of chronic infections. Studies on microbial biofilms in the past decade involved mainly the understanding of environment signals, genetic elements and molecular mechanisms in biofilm formation, tolerance and dispersal. The knowledge obtained from the studies of these mechanisms is crucial in the establishment of strategies to eradicate or to prevent biofilm formation. Currently, biofilm infections are usually treated with combinations of antibiotics and surgical removal, in addition to frequent replacement of the infected device. More recently, specific natural sources have been identified as antibiofilm agents against this pathogen. This review will highlight the recent progress made by plant-derived compounds against P. aeruginosa biofilm infections in both in vitro or in vivo models.
    Matched MeSH terms: Biofilms/drug effects
  8. Transcriptional responses of Streptococcus gordonii and Fusobacterium nucleatum to coaggregation
    Mutha NVR, Mohammed WK, Krasnogor N, Tan GYA, Choo SW, Jakubovics NS
    Mol Oral Microbiol, 2018 12;33(6):450-464.
    PMID: 30329223 DOI: 10.1111/omi.12248
    Cell-cell interactions between genetically distinct bacteria, known as coaggregation, are important for the formation of mixed-species biofilms such as dental plaque. Interactions lead to gene regulation in the partner organisms that may be critical for adaptation and survival in mixed-species biofilms. Here, gene regulation responses to coaggregation between Streptococcus gordonii and Fusobacterium nucleatum were studied using dual RNA-Seq. Initially, S. gordonii was shown to coaggregate strongly with F. nucleatum in buffer or human saliva. Using confocal laser scanning microscopy and transmission electron microscopy, cells of different species were shown to be evenly distributed throughout the coaggregate and were closely associated with one another. This distribution was confirmed by serial block face sectioning scanning electron microscopy, which provided high resolution three-dimensional images of coaggregates. Cell-cell sensing responses were analysed 30 minutes after inducing coaggregation in human saliva. By comparison with monocultures, 16 genes were regulated following coaggregation in F. nucleatum whereas 119 genes were regulated in S. gordonii. In both species, genes involved in amino acid and carbohydrate metabolism were strongly affected by coaggregation. In particular, one 8-gene operon in F. nucleatum encoding sialic acid uptake and catabolism was up-regulated 2- to 5-fold following coaggregation. In S. gordonii, a gene cluster encoding functions for phosphotransferase system-mediated uptake of lactose and galactose was down-regulated up to 3-fold in response to coaggregation. The genes identified in this study may play key roles in the development of mixed-species communities and represent potential targets for approaches to control dental plaque accumulation.
    Matched MeSH terms: Biofilms/growth & development*
  9. Diverse Profiles of Biofilm and Adhesion Genes in Staphylococcus Aureus Food Strains Isolated from Sushi and Sashimi
    Puah SM, Tan JAMA, Chew CH, Chua KH
    J Food Sci, 2018 Sep;83(9):2337-2342.
    PMID: 30101982 DOI: 10.1111/1750-3841.14300
    Staphylococcus aureus is able to form multilayer biofilms embedded within a glycocalyx or slime layer. Biofilm formation poses food contamination risks and can subsequently increase the risk of food poisoning. Identification of food-related S. aureus strains will provide additional data on staphylococcal food poisoning involved in biofilm formation. A total of 52 S. aureus strains isolated from sushi and sashimi was investigated to study their ability for biofilm formation using crystal violet staining. The presence of accessory gene regulator (agr) groups and 15 adhesion genes was screened and their associations in biofilm formation were studied. All 52 S. aureus strains showed biofilm production on the tested hydrophobic surface with 44% (23/52) strains classified as strong, 33% (17/52) as moderate, and 23% (12/52) as weak biofilm producers. The frequency of agr-positive strains was 71% (agr group 1 = 21 strains; agr group 2 = 2 strains; agr group 3 = 12 strains; agr group 4 = 2 strains) whereas agr-negative strains were 29% (15/52). Twelve adhesion genes were detected and 98% of the S. aureus strains carried at least one adhesion gene. The ebps was significantly (p < .05) associated with strong biofilm producing strains. In addition, eno, clfA, icaAD, sasG, fnbB, cna, and sasC were significantly higher in the agr-positive group compared to the agr-negative group. The results of this study suggest that the presence of ebps, eno, clfA, icaAD, sasG, fnbB, cna, and sasC may play an important role in enhancing the stage of biofilm-related infections and warrants further investigation.

    PRACTICAL APPLICATION: This work contributes to the knowledge on the biofilm formation and the distribution of agr groups in S. aureus strains as well as microbial surface components in recognizing adherence matrix molecules of organisms isolated from ready-to-eat sushi and sashimi. The findings provide valuable information to further study the roles of specific genes in causing biofilm-related infections.

    Matched MeSH terms: Biofilms*
  10. The antifungal agent of silver nanoparticles activated by diode laser as light source to reduce C. albicans biofilms: an in vitro study
    Astuti SD, Puspita PS, Putra AP, Zaidan AH, Fahmi MZ, Syahrom A, et al.
    Lasers Med Sci, 2019 Jul;34(5):929-937.
    PMID: 30413898 DOI: 10.1007/s10103-018-2677-4
    Candida albicans is a normal flora caused fungal infections and has the ability to form biofilms. The aim of this study was to improve the antifungal effect of silver nanoparticles (AgNPs) and the light source for reducing the biofilm survival of C. albicans. AgNPs were prepared by silver nitrate (AgNO3) and trisodium citrate (Na3C6H5O7). To determine the antifungal effect of treatments on C. albicans biofilm, samples were distributed into four groups; L + P+ was treatment with laser irradiation and AgNPs; L + P- was treatment with laser irradiation only; L - P+ was treatment with AgNPs only (control positive); L - P- was no treatment with laser irradiation or AgNPs (control negative). The growth of fungi had been monitored by measuring the optical density at 405 nm with ELISA reader. The particle size of AgNPs was measured by using (particle size analyzer) and the zeta potential of AgNPs was measured by using Malvern zetasizer. The PSA test showed that the particle size of AgNPs was distributed between 7.531-5559.644 nm. The zeta potentials were found lower than - 30 mV with pH of 7, 9 or 11. The reduction percentage was analyzed by ANOVA test. The highest reduction difference was given at a lower level irradiation because irradiation with a density energy of 6.13 ± 0.002 J/cm2 resulted in the biofilm reduction of 7.07 ± 0.23% for the sample without AgNPs compared to the sample with AgNPs that increased the biofilm reduction of 64.48 ± 0.07%. The irradiation with a 450-nm light source had a significant fungicidal effect on C. albicans biofilm. The combination of light source and AgNPs provides an increase of biofilm reduction compared to the light source itself.
    Matched MeSH terms: Biofilms/drug effects*
  11. Synthesis, Bacterial biofilm inhibition and cytotoxicity of new N-Alkyl/aralkyl-N-(2,3-dihydro-1,4-benzodioxin-6-yl)-4-nitrobenzenesulfonamides
    Abbasi MA, Zeb A, Rehman A, Siddiqui SZ, Shah SAA, Shahid M, et al.
    Pak J Pharm Sci, 2020 Jan;33(1):41-47.
    PMID: 32122829
    The current research was commenced by reaction of 1,4-benzodioxane-6-amine (1) with 4-nitrobenzenesulfonyl chloride (2) in the presence of aqueous base under dynamic pH control at 9 to yield N-(2,3-dihydro-1,4-benzodioxin-6-yl)-4-nitrobenzenesulfonamide (3) which was further reacted with a series of alkyl/aralkyl halides (4a-i) in polar aprotic solvent using catalytic amount of lithium hydride which acts as base to afford some new N-alkyl/aralkyl-N-(2,3-dihydro-1,4-benzodioxin-6-yl)-4-nitrobenzenesulfonamides (5a-i). The projected structures of all the synthesized derivatives were characterized by contemporary techniques i.e., IR, 1H-NMR and EIMS. The biofilm Inhibitory action of all synthesized molecules was carried out against Escherichia coli and Bacillus subtilis. It was inferred from their results that 5f and 5e exhibited suitable inhibitory action against the biofilms of these bacterial strains. Moreover, their cytotoxicity was also checked and it was concluded that these synthesized molecules displayed docile cytotoxicity.
    Matched MeSH terms: Biofilms/drug effects*
  12. 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: Biofilms/drug effects*
  13. Biofilm-Related Diseases and Omics: Global Transcriptional Profiling of Enterococcus faecium Reveals Different Gene Expression Patterns in the Biofilm and Planktonic Cells
    Lim SY, Teh CSJ, Thong KL
    OMICS, 2017 10;21(10):592-602.
    PMID: 29049010 DOI: 10.1089/omi.2017.0119
    Enterococcus faecium is an opportunistic pathogen with a remarkable ability to acquire resistance toward multiple antibiotics, including those of last-resort drugs such as vancomycin and daptomycin. The occurrence of vancomycin-resistant E. faecium is on the rise and there is a need to understand the virulence of this organism. One of the factors that contributes to the virulence is the ability to form biofilms. Since bacteria in biofilm state are more resistant to antibiotics and host immune response, understanding the molecular mechanism of biofilm development is important to control biofilm-related diseases. The aim of this study was to determine the global gene expression profiles of an E. faecium strain, VREr5, during the early event of sessile growth compared with its planktonic phase through RNA-sequencing approach. The results clearly illustrated distinct expression profiles of the planktonic and biofilm cells. A total of 177 genes were overexpressed in the biofilm cells. Most of them encode for proteins involved in adherence, such as the ebpABCfm locus. Genes associated with plasmid replication, gene exchange, and protein synthesis were also upregulated during the early event of biofilm development. Furthermore, the transcriptome analysis also identified genes such as fsrB, luxS, and spx that might suppress biofilm formation in VREr5. The putative biofilm-related bee locus was found to be downregulated. These new findings could provide caveats for future studies on the regulation and maintenance of biofilm and development of biomarkers for biofilm-related diseases.
    Matched MeSH terms: Biofilms/growth & development*
  14. The Role of Nanoparticles in the Inhibition of Multidrug-Resistant Bacteria and Biofilms
    AlMatar M, Makky EA, Var I, Koksal F
    Curr Drug Deliv, 2018;15(4):470-484.
    PMID: 29219055 DOI: 10.2174/1567201815666171207163504
    BACKGROUND: Until recently, one of the main reasons for mortality has been infectious diseases, and bacteria that are drug-resistant have emerged as a result of the wide application, as well as the misuse of antibacterial medications. Having multidrug-resistance, bacteria present a great problem for the efficient management of bacterial infections and this challenge has resulted in the creation of other means of dealing with bacterial diseases. Of late, metallic nanoparticles (NPs), employed as antibacterial agents, have the potential for use against resistance to bacterial drugs.

    OBJECTIVE: The mechanisms of bacterial resistance are described in this review and this is followed by an outline of the features and uses of metallic NPs as antibiotic agents to address bacteria that are antibiotic- sensitive and resistant. Additionally, a general impression of metallic NPs as antibiofilm bactericidal agents is presented.

    CONCLUSION: Biofilms and bacterial strains that are resistant to antibiotics present a grave public health challenge and this has enhanced the need to develop new bactericidal agents. Therefore, nanomaterials are considered as a potential platform for managing bacterial infections.

    Matched MeSH terms: Biofilms/drug effects*
  15. Fulltext Advancements in nano drug delivery systems: a challenge for biofilms in respiratory diseases
    Dua K, de Jesus Andreoli Pinto T, Chellappan DK, Gupta G, Bebawy M, Hansbro PM
    Panminerva Med, 2018 03;60(1):35-36.
    PMID: 29370678 DOI: 10.23736/S0031-0808.18.03402-X
    Matched MeSH terms: Biofilms*
  16. Comparative Study of the Effects of Fluconazole and Voriconazole on Candida glabrata, Candida parapsilosis and Candida rugosa Biofilms
    Madhavan P, Jamal F, Pei CP, Othman F, Karunanidhi A, Ng KP
    Mycopathologia, 2018 Jun;183(3):499-511.
    PMID: 29380188 DOI: 10.1007/s11046-018-0243-z
    Infections by non-albicans Candida species are a life-threatening condition, and formation of biofilms can lead to treatment failure in a clinical setting. This study was aimed to demonstrate the in vitro antibiofilm activity of fluconazole (FLU) and voriconazole (VOR) against C. glabrata, C. parapsilosis and C. rugosa with diverse antifungal susceptibilities to FLU and VOR. The antibiofilm activities of FLU and VOR in the form of suspension as well as pre-coatings were assessed by XTT [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] reduction assay. Morphological and intracellular changes exerted by the antifungal drugs on Candida cells were examined by scanning electron microscope (SEM) and transmission electron microscope (TEM). The results of the antibiofilm activities showed that FLU drug suspension was capable of killing C. parapsilosis and C. rugosa at minimum inhibitory concentrations (MICs) of 4× MIC FLU and 256× MIC FLU, respectively. While VOR MICs ranging from 2× to 32× were capable of killing the biofilms of all Candida spp tested. The antibiofilm activities of pre-coated FLU were able to kill the biofilms at ¼× MIC FLU and ½× MIC FLU for C. parapsilosis and C. rugosa strains, respectively. While pre-coated VOR was able to kill the biofilms, all three Candida sp at ½× MIC VOR. SEM and TEM examinations showed that FLU and VOR treatments exerted significant impact on Candida cell with various degrees of morphological changes. In conclusion, a fourfold reduction in MIC50 of FLU and VOR towards ATCC strains of C. glabrata, C. rugosa and C. rugosa clinical strain was observed in this study.
    Matched MeSH terms: Biofilms/drug effects*
  17. Antibiofilm activity and mode of action of DMSO alone and its combination with afatinib against Gram-negative pathogens
    Yahya MFZR, Alias Z, Karsani SA
    Folia Microbiol (Praha), 2018 Jan;63(1):23-30.
    PMID: 28540585 DOI: 10.1007/s12223-017-0532-9
    Biofilms are complex microbial communities that tend to attach to either biotic or abiotic surface. Enclosed in a self-produced extracellular polymeric substance (EPS) matrix, the biofilms often cause persistent infections. The objective of this study was to investigate the antibiofilm activity of dimethyl sulfoxide (DMSO) and afatinib against Gram-negative pathogens. Test microorganisms used in this study were Escherichia coli ATCC 1299, Pseudomonas aeruginosa ATCC 10145, and Salmonella typhimurium ATCC 14028. Biofilms were developed in 96-well microplate at 37°C for 24 h. Following removal of non-adherent cells, analysis of biofilm viability, biofilm biomass, and extracellular polymeric substances (EPS) matrix were performed using resazurin assay, crystal violet assay, and attenuated total reflectance fourier transform infrared (ATR-FTIR) spectroscopy, respectively. Bradford protein assay was conducted to determine the total amount of EPS proteins. The results demonstrated that both 32% DMSO alone and its combination with 3.2 μg/mL afatinib were effective in killing biofilm cells and reducing biofilm biomass. IR spectral variations of EPS matrix of biofilms in the range between 1700 and 900 cm-1 were also observed. Reduction in EPS proteins verified the chemical modifications of EPS matrix. In conclusion, 32% DMSO alone and its combination with 3.2 μg/mL afatinib showed remarkable antibiofilm activities against Gram-negative pathogens. It was suggested that the biofilm inhibition was mediated by the chemical modification of EPS matrix.
    Matched MeSH terms: Biofilms/drug effects*
  18. Fulltext Iron and Virulence in Stenotrophomonas Maltophilia: All We Know So Far
    Kalidasan V, Joseph N, Kumar S, Awang Hamat R, Neela VK
    Front Cell Infect Microbiol, 2018;8:401.
    PMID: 30483485 DOI: 10.3389/fcimb.2018.00401
    Stenotrophomonas maltophilia is a multi-drug-resistant global opportunistic nosocomial pathogen, which possesses a huge number of virulence factors and antibiotics resistance characteristics. Iron has a crucial contribution toward growth and development, cell growth and proliferation, and pathogenicity. The bacterium found to acquire iron for its cellular process through the expression of two iron acquisition systems. Two distinct pathways for iron acquisition are encoded by the S. maltophilia genome-a siderophore-and heme-mediated iron uptake system. The entAFDBEC operon directs the production of the enterobactin siderophore of catecholate in nature, while heme uptake relies on hgbBC and potentially hmuRSTUV operon. Fur and sigma factors are regulators of S. maltophilia under iron-limited condition. Iron potentially act as a signal which plays an important role in biofilm formation, extracellular polymeric substances (EPS), extracellular enzymes production, oxidative stress response, diffusible signal factor (DSF) and siderophore production in S. maltophilia. This review summarizes the current knowledge of iron acquisition in S. maltophilia and the critical role of iron in relation to its pathogenicity.
    Matched MeSH terms: Biofilms/growth & development
  19. Fulltext Association of some Campylobacter jejuni with Pseudomonas aeruginosa biofilms increases attachment under conditions mimicking those in the environment
    Teh AHT, Lee SM, Dykes GA
    PLoS One, 2019;14(4):e0215275.
    PMID: 30970009 DOI: 10.1371/journal.pone.0215275
    Campylobacter jejuni is a microaerophilic bacterial species which is a major food-borne pathogen worldwide. Attachment and biofilm formation have been suggested to contribute to the survival of this fastidious bacteria in the environment. In this study the attachment of three C. jejuni strains (C. jejuni strains 2868 and 2871 isolated from poultry and ATCC 33291) to different abiotic surfaces (stainless steel, glass and polystyrene) alone or with Pseudomonas aeruginosa biofilms on them, in air at 25°C and under static or flow conditions, were investigated using a modified Robbins Device. Bacteria were enumerated and scanning electron microscopy was carried out. The results indicated that both C. jejuni strains isolated from poultry attached better to Pseudomonas aeruginosa biofilms on abiotic surfaces than to the surfaces alone under the different conditions tested. This suggests that biofilms of other bacterial species may passively protect C. jejuni against shear forces and potentially oxygen stress which then contribute to their persistence in environments which are detrimental to them. By contrast the C. jejuni ATCC 33291 strain did not attach differentially to P. aeruginosa biofilms, suggesting that different C. jejuni strains may have alternative strategies for persistence in the environment. This study supports the hypothesis that C. jejuni do not form biofilms per se under conditions they encounter in the environment but simply attach to surfaces or biofilms of other species.
    Matched MeSH terms: Biofilms/growth & development*
  20. Fulltext Potential of Superhydrophobic Surface for Blood-Contacting Medical Devices
    Wu XH, Liew YK, Mai CW, Then YY
    Int J Mol Sci, 2021 Mar 24;22(7).
    PMID: 33805207 DOI: 10.3390/ijms22073341
    Medical devices are indispensable in the healthcare setting, ranging from diagnostic tools to therapeutic instruments, and even supporting equipment. However, these medical devices may be associated with life-threatening complications when exposed to blood. To date, medical device-related infections have been a major drawback causing high mortality. Device-induced hemolysis, albeit often neglected, results in negative impacts, including thrombotic events. Various strategies have been approached to overcome these issues, but the outcomes are yet to be considered as successful. Recently, superhydrophobic materials or coatings have been brought to attention in various fields. Superhydrophobic surfaces are proposed to be ideal blood-compatible biomaterials attributed to their beneficial characteristics. Reports have substantiated the blood repellence of a superhydrophobic surface, which helps to prevent damage on blood cells upon cell-surface interaction, thereby alleviating subsequent complications. The anti-biofouling effect of superhydrophobic surfaces is also desired in medical devices as it resists the adhesion of organic substances, such as blood cells and microorganisms. In this review, we will focus on the discussion about the potential contribution of superhydrophobic surfaces on enhancing the hemocompatibility of blood-contacting medical devices.
    Matched MeSH terms: Biofilms/drug effects
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