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Sample records for furanones inhibit biofilm

  1. Inhibition of biofilm formation in Bacillus subtilis by new halogenated furanones.

    Science.gov (United States)

    Kayumov, Airat R; Khakimullina, Elvina N; Sharafutdinov, Irshad S; Trizna, Elena Y; Latypova, Lilia Z; Thi Lien, Hoang; Margulis, Anna B; Bogachev, Mikhail I; Kurbangalieva, Almira R

    2015-05-01

    Gram-positive bacteria can cause various infections including hospital-acquired infections. While in the biofilm, the resistance of bacteria to both antibiotics and the human immune system is increased causing difficulties in the treatment. Bacillus subtilis, a non-pathogenic Gram-positive bacterium, is widely used as a model organism for studying biofilm formation. Here we investigated the effect of novel synthesized chloro- and bromo-containing 2(5H)-furanones on biofilm formation by B. subtilis. Mucobromic acid (3,4-dibromo-5-hydroxy-2(5H)-furanone) and the two derivatives of mucochloric acid (3,4-dichloro-5-hydroxy-2(5H)-furanone)-F8 and F12-were found to inhibit the growth and to efficiently prevent biofilm formation by B. subtilis. Along with the low production of polysaccharide matrix and repression of the eps operon, strong repression of biofilm-related yqxM also occurred in the presence of furanones. Therefore, our data confirm that furanones affect significantly the regulatory pathway(s) leading to biofilm formation. We propose that the global regulator, Spo0A, is one of the potential putative cellular targets for these compounds.

  2. Inhibition of quorum sensing in Pseudomonas aeruginosa biofilm bacteria by a halogenated furanone compound

    DEFF Research Database (Denmark)

    Hentzer, Morten; Riedel, K.; Rasmussen, Thomas Bovbjerg

    2002-01-01

    Novel molecular tools have been constructed which allow for in situ detection of N-acyl homoserine lactone (AHL)-mediated quorum sensing in Pseudomonas aeruginosa biofilms. The reporter responds to AHL activation of LasR lay expression of an unstable version of the green-fluorescent protein (Gfp...

  3. Synthetic furanones inhibit quorum-sensing and enhance bacterial clearance in Pseudomonas aeruginosa lung infection in mice

    DEFF Research Database (Denmark)

    Wu, H.; Song, Z.; Hentzer, Morten

    2004-01-01

    Introduction: Antibiotics are used to treat bacterial infections by killing the bacteria or inhibiting their growth, but resistance to antibiotics can develop readily. The discovery that bacterial quorum-sensing regulates bacterial virulence as well as the formation of biofilms opens up new ways...... to control certain bacterial infections. Furanone compounds capable of inhibiting bacterial quorum-sensing systems have been isolated from the marine macro alga Delisea pulchra. Objectives: Two synthetic furanones were tested for their ability to attenuate bacterial virulence in the mouse models of chronic...

  4. Halogenated furanones inhibit quorum sensing through accelerated LuxR turnover

    DEFF Research Database (Denmark)

    Manefield, M.; Rasmussen, Thomas Bovbjerg; Henzter, M.

    2002-01-01

    fischeri overproduced in Escherichia coli. Whilst a stable interaction between the algal metabolite and the bacterial protein was not found, it was noted by Western analysis that the half-life of the protein is reduced up to 100-fold in the presence of halogenated furanones. This suggests that halogenated...... that the reduction in LuxR concentration is the mechanism by which furanones control expression of AHL-dependent phenotypes. The mode of action by which halogenated furanones reduce cellular concentrations of the LuxR protein remains to be characterized....

  5. Silver-Palladium Surfaces Inhibit Biofilm Formation

    DEFF Research Database (Denmark)

    Chiang, Wen-Chi; Schroll, Casper; Hilbert, Lisbeth Rischel

    2009-01-01

    Undesired biofilm formation is a major concern in many areas. In the present study, we investigated biofilm-inhibiting properties of a silver-palladium surface that kills bacteria by generating microelectric fields and electrochemical redox processes. For evaluation of the biofilm inhibition...... efficacy and study of the biofilm inhibition mechanism, the silver-sensitive Escherichia coli J53 and the silver-resistant E. coli J53[pMG101] strains were used as model organisms, and batch and flow chamber setups were used as model systems. In the case of the silver-sensitive strain, the silver......-palladium surfaces killed the bacteria and prevented biofilm formation under conditions of low or high bacterial load. In the case of the silver-resistant strain, the silver-palladium surfaces killed surface-associated bacteria and prevented biofilm formation under conditions of low bacterial load, whereas under...

  6. Aspartate inhibits Staphylococcus aureus biofilm formation.

    Science.gov (United States)

    Yang, Hang; Wang, Mengyue; Yu, Junping; Wei, Hongping

    2015-04-01

    Biofilm formation renders Staphylococcus aureus highly resistant to conventional antibiotics and host defenses. Four D-amino acids (D-Leu, D-Met, D-Trp and D-Tyr) have been reported to be able to inhibit biofilm formation and disassemble established S. aureus biofilms. We report here for the first time that both D- and L-isoforms of aspartate (Asp) inhibited S. aureus biofilm formation on tissue culture plates. Similar biofilm inhibition effects were also observed against other staphylococcal strains, including S. saprophyticus, S. equorum, S. chromogenes and S. haemolyticus. It was found that Asp at high concentrations (>10 mM) inhibited the growth of planktonic N315 cells, but at subinhibitory concentrations decreased the cellular metabolic activity without influencing cell growth. The decreased cellular metabolic activity might be the reason for the production of less protein and DNA in the matrix of the biofilms formed in the presence of Asp. However, varied inhibition efficacies of Asp were observed for biofilms formed by clinical staphylococcal isolates. There might be mechanisms other than decreasing the metabolic activity, e.g. the biofilm phenotypes, affecting biofilm formation in the presence of Asp. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  7. Simvastatin inhibits Candida albicans biofilm in vitro.

    Science.gov (United States)

    Liu, Geoffrey; Vellucci, Vincent F; Kyc, Stephanie; Hostetter, Margaret K

    2009-12-01

    By inhibiting the conversion of 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) to mevalonate, statins impair cholesterol metabolism in humans. We reasoned that statins might similarly interfere with the biosynthesis of ergosterol, the major sterol of the yeast cell membrane. As assessed by spectrophotometric and microscopic analysis, significant inhibition of biofilm production was noted after 16-h incubation with 1, 2.5, and 5 muM simvastatin, concentrations that did not affect growth, adhesion, or hyphal formation by C. albicans in vitro. Higher concentrations (10, 20, and 25 muM simvastatin) inhibited biofilm by >90% but also impaired growth. Addition of exogenous ergosterol (90 muM) overcame the effects of 1 and 2.5 muM simvastatin, suggesting that at least one mechanism of inhibition is interference with ergosterol biosynthesis. Clinical isolates from blood, skin, and mucosal surfaces produced biofilms; biofilms from bloodstream isolates were similarly inhibited by simvastatin. In the absence of fungicidal activity, simvastatin's interruption of a critical step in an essential metabolic pathway, highly conserved from yeast to man, has unexpected effects on biofilm production by a eukaryotic pathogen.

  8. Ginger Extract Inhibits Biofilm Formation by Pseudomonas aeruginosa PA14

    Science.gov (United States)

    Kim, Han-Shin; Park, Hee-Deung

    2013-01-01

    Bacterial biofilm formation can cause serious problems in clinical and industrial settings, which drives the development or screening of biofilm inhibitors. Some biofilm inhibitors have been screened from natural products or modified from natural compounds. Ginger has been used as a medicinal herb to treat infectious diseases for thousands of years, which leads to the hypothesis that it may contain chemicals inhibiting biofilm formation. To test this hypothesis, we evaluated ginger’s ability to inhibit Pseudomonas aeruginosa PA14 biofilm formation. A static biofilm assay demonstrated that biofilm development was reduced by 39–56% when ginger extract was added to the culture. In addition, various phenotypes were altered after ginger addition of PA14. Ginger extract decreased production of extracellular polymeric substances. This finding was confirmed by chemical analysis and confocal laser scanning microscopy. Furthermore, ginger extract formed noticeably less rugose colonies on agar plates containing Congo red and facilitated swarming motility on soft agar plates. The inhibition of biofilm formation and the altered phenotypes appear to be linked to a reduced level of a second messenger, bis-(3′-5′)-cyclic dimeric guanosine monophosphate. Importantly, ginger extract inhibited biofilm formation in both Gram-positive and Gram-negative bacteria. Also, surface biofilm cells formed with ginger extract detached more easily with surfactant than did those without ginger extract. Taken together, these findings provide a foundation for the possible discovery of a broad spectrum biofilm inhibitor. PMID:24086697

  9. Halogenated furanones from the red alga, Delisea pulchra, inhibit carbapenem antibiotic synthesis and exoenzyme virulence factor production in the phytopathogen Erwinia carotovora

    DEFF Research Database (Denmark)

    Manefield, M.; Welch, M.; Givskov, Michael Christian

    2001-01-01

    The plant pathogen Erwinia carotovora regulates expression of virulence factors and antibiotic production via an N-3- oxohexanoyl-L-homoserine lactone (3-oxo-C6-HSL) dependent quorum sensing mechanism. The marine alga Delisea pulchra produces halogenated furanones known to antagonise 3-oxo-C6-HSL...

  10. Kaffir lime leaves extract inhibits biofilm formation by Streptococcus mutans.

    Science.gov (United States)

    Kooltheat, Nateelak; Kamuthachad, Ludthawun; Anthapanya, Methinee; Samakchan, Natthapon; Sranujit, Rungnapa Pankla; Potup, Pachuen; Ferrante, Antonio; Usuwanthim, Kanchana

    2016-04-01

    Although kaffir lime has been reported to exhibit antioxidant and antileukemic activity, little is known about the antimicrobial effect of kaffir lime extract. Because Streptococcus mutans has been known to cause biofilm formation, it has been considered the most important causative pathogen of dental caries. Thus, the effective control of its effects on the oral biofilm is the key to the prevention of dental caries. The aims of the present study were to investigate the effect of kaffir lime leaves extract on biofilm formation and its antibacterial activity on S. mutans. We examined the effect of kaffir lime leaves extract on growth and biofilm formation of S. mutans. For the investigation we used a kaffir lime extract with high phenolic content. The minimum inhibitory concentration of the extract was determined by broth microdilution assay. The inhibitory effect of the test substances on biofilm formation was also investigated by biofilm formation assay and qRT-PCR of biofilm formation-associated genes. Kaffir lime leaves extract inhibits the growth of S. mutans, corresponding to the activity of an antibiotic, ampicillin. Formation of biofilm by S. mutans was also inhibited by the extract. These results were confirmed by the down-regulation of genes associated with the biofilm formation. The findings highlight the ability of kaffir lime leaves extract to inhibit S. mutans activity, which may be beneficial in the prevention of biofilm formation on dental surface, reducing dental plaque and decreasing the chance of dental carries. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Lactobacillus plantarum lipoteichoic acid inhibits biofilm formation of Streptococcus mutans

    Science.gov (United States)

    Ahn, Ki Bum; Baik, Jung Eun; Park, Ok-Jin; Yun, Cheol-Heui

    2018-01-01

    Dental caries is a biofilm-dependent oral disease and Streptococcus mutans is the known primary etiologic agent of dental caries that initiates biofilm formation on tooth surfaces. Although some Lactobacillus strains inhibit biofilm formation of oral pathogenic bacteria, the molecular mechanisms by which lactobacilli inhibit bacterial biofilm formation are not clearly understood. In this study, we demonstrated that Lactobacillus plantarum lipoteichoic acid (Lp.LTA) inhibited the biofilm formation of S. mutans on polystyrene plates, hydroxyapatite discs, and dentin slices without affecting the bacterial growth. Lp.LTA interferes with sucrose decomposition of S. mutans required for the production of exopolysaccharide, which is a main component of biofilm. Lp.LTA also attenuated the biding of fluorescein isothiocyanate-conjugated dextran to S. mutans, which is known to have a high affinity to exopolysaccharide on S. mutans. Dealanylated Lp.LTA did not inhibit biofilm formation of S. mutans implying that D-alanine moieties in the Lp.LTA structure were crucial for inhibition. Collectively, these results suggest that Lp.LTA attenuates S. mutans biofilm formation and could be used to develop effective anticaries agents. PMID:29420616

  12. Maggot excretions inhibit biofilm formation on biomaterials.

    Science.gov (United States)

    Cazander, Gwendolyn; van de Veerdonk, Mariëlle C; Vandenbroucke-Grauls, Christina M J E; Schreurs, Marco W J; Jukema, Gerrolt N

    2010-10-01

    Biofilm-associated infections in trauma surgery are difficult to treat with conventional therapies. Therefore, it is important to develop new treatment modalities. Maggots in captured bags, which are permeable for larval excretions/secretions, aid in healing severe, infected wounds, suspect for biofilm formation. Therefore we presumed maggot excretions/secretions would reduce biofilm formation. We studied biofilm formation of Staphylococcus aureus, Staphylococcus epidermidis, Klebsiella oxytoca, Enterococcus faecalis, and Enterobacter cloacae on polyethylene, titanium, and stainless steel. We compared the quantities of biofilm formation between the bacterial species on the various biomaterials and the quantity of biofilm formation after various incubation times. Maggot excretions/secretions were added to existing biofilms to examine their effect. Comb-like models of the biomaterials, made to fit in a 96-well microtiter plate, were incubated with bacterial suspension. The formed biofilms were stained in crystal violet, which was eluted in ethanol. The optical density (at 595 nm) of the eluate was determined to quantify biofilm formation. Maggot excretions/secretions were pipetted in different concentrations to (nonstained) 7-day-old biofilms, incubated 24 hours, and finally measured. The strongest biofilms were formed by S. aureus and S. epidermidis on polyethylene and the weakest on titanium. The highest quantity of biofilm formation was reached within 7 days for both bacteria. The presence of excretions/secretions reduced biofilm formation on all biomaterials. A maximum of 92% of biofilm reduction was measured. Our observations suggest maggot excretions/secretions decrease biofilm formation and could provide a new treatment for biofilm formation on infected biomaterials.

  13. How Delisea pulchra furanones affect quorum sensing and swarming motility in Serratia liquefaciens MG1

    DEFF Research Database (Denmark)

    Rasmussen, Thomas Bovbjerg; Manefield, M.; Andersen, Jens Bo

    2000-01-01

    Halogenated furanones produced by the benthic marine macroalga Delisea pulchra inhibit swarming motility of Serratia liquefaciens MG1. This study demonstrates that exogenously added furanones control transcription of the quorum sensing regulated gene swrA in competition with the cognate signal...

  14. Inhibition of Staphylococcus epidermidis Biofilm by Trimethylsilane Plasma Coating

    Science.gov (United States)

    Ma, Yibao; Jones, John E.; Ritts, Andrew C.; Yu, Qingsong

    2012-01-01

    Biofilm formation on implantable medical devices is a major impediment to the treatment of nosocomial infections and promotes local progressive tissue destruction. Staphylococcus epidermidis infections are the leading cause of biofilm formation on indwelling devices. Bacteria in biofilms are highly resistant to antibiotic treatment, which in combination with the increasing prevalence of antibiotic resistance among human pathogens further complicates treatment of biofilm-related device infections. We have developed a novel plasma coating technology. Trimethylsilane (TMS) was used as a monomer to coat the surfaces of 316L stainless steel and grade 5 titanium alloy, which are widely used in implantable medical devices. The results of biofilm assays demonstrated that this TMS coating markedly decreased S. epidermidis biofilm formation by inhibiting the attachment of bacterial cells to the TMS-coated surfaces during the early phase of biofilm development. We also discovered that bacterial cells on the TMS-coated surfaces were more susceptible to antibiotic treatment than their counterparts in biofilms on uncoated surfaces. These findings suggested that TMS coating could result in a surface that is resistant to biofilm development and also in a bacterial community that is more sensitive to antibiotic therapy than typical biofilms. PMID:22964248

  15. Axenic aerobic biofilms inhibit corrosion of copper and aluminum.

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    Jayaraman, A; Ornek, D; Duarte, D A; Lee, C C; Mansfeld, F B; Wood, T K

    1999-11-01

    The corrosion behavior of unalloyed copper and aluminum alloy 2024 in modified Baar's medium has been studied with continuous reactors using electrochemical impedance spectroscopy. An axenic aerobic biofilm of either Pseudomonas fragi K or Bacillus brevis 18 was able to lessen corrosion as evidenced by a consistent 20-fold increase in the low-frequency impedance value of copper as well as by a consistent four- to seven-fold increase in the polarization resistance of aluminum 2024 after six days exposure compared to sterile controls. This is the first report of axenic aerobic biofilms inhibiting generalized corrosion of copper and aluminum. Addition of the representative sulfate-reducing bacterium (SRB) Desulfovibrio vulgaris (to simulate consortia corrosion behavior) to either the P. fragi K or B. brevis 18 protective biofilm on copper increased the corrosion to that of the sterile control unless antibiotic (ampicillin) was added to inhibit the growth of SRB in the biofilm.

  16. Organic compounds inhibiting S. epidermidis adhesion and biofilm formation

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Zhiqiang [Department of Systems Biology, Technical University of Denmark, Dk-2800 Kgs. Lyngby (Denmark); Key Laboratory of Medical Molecular Virology of Ministry of Education and Public Health, Institute of Medical Microbiology and Institutes of Biomedical Science, Shanghai Medical School of Fudan University, Yi Xue Yuan Road 138, Shanghai 200032 (China); Division of Infectious Diseases, Department of Medicine, Hollings Cancer Center, Medical University of South Carolina, 86 Jonathan Lucas Street, Charleston, SC 29425 (United States); Zhang, Jingdong; Hu, Yifan; Chi, Qijin [Department of Chemistry, Building 207, NanoDTU, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark); Mortensen, Ninell P. [Department of Systems Biology, Technical University of Denmark, Dk-2800 Kgs. Lyngby (Denmark); Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37932 (United States); Qu, Di [Key Laboratory of Medical Molecular Virology of Ministry of Education and Public Health, Institute of Medical Microbiology and Institutes of Biomedical Science, Shanghai Medical School of Fudan University, Yi Xue Yuan Road 138, Shanghai 200032 (China); Molin, Soren [Department of Systems Biology, Technical University of Denmark, Dk-2800 Kgs. Lyngby (Denmark); Ulstrup, Jens, E-mail: ju@kemi.dtu.dk [Department of Chemistry, Building 207, NanoDTU, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark)

    2009-07-15

    The formation of biofilms on surfaces of indwelling medical devices is a serious medical problem. Staphylococcus epidermidis is a common pathogen found to colonize implanted devices and as a biofilm is more resistant to the host immune system as well as to antibiotic treatments. Combating S. epidermidis infections by preventing or eradicating biofilm formation of the bacterium is therefore a medically important challenge. We report here a study of biofilm formation of S. epidermidis on solid surfaces using a combination of confocal laser scanning (CLSM) and atomic force microscopy (AFM) in both air and aqueous environments. We have investigated the inhibitory effects of surfaces treated with four organic compounds, two benzoate derivatives denoted as compound 59 and 75 and two carboxamide derivatives denoted as compound 47 and 73, on S. epidermidis adhesion and biofilm formation. All four compounds evoke significant inhibitory effects on the formation of S. epidermidis biofilms with compounds 47 and 73 being most effective. None of the compounds were found to inhibit growth of S. epidermidis in liquid cultures. Bacteria attached to the substrate when exposed to the compounds were not affected indicating that these compounds inhibit initial adhesion. These results suggest a pretreatment for medically implanted surfaces that can prevent the biofilm formation and reduce infection.

  17. Organic compounds inhibiting S. epidermidis adhesion and biofilm formation

    International Nuclear Information System (INIS)

    Qin, Zhiqiang; Zhang, Jingdong; Hu, Yifan; Chi, Qijin; Mortensen, Ninell P.; Qu, Di; Molin, Soren; Ulstrup, Jens

    2009-01-01

    The formation of biofilms on surfaces of indwelling medical devices is a serious medical problem. Staphylococcus epidermidis is a common pathogen found to colonize implanted devices and as a biofilm is more resistant to the host immune system as well as to antibiotic treatments. Combating S. epidermidis infections by preventing or eradicating biofilm formation of the bacterium is therefore a medically important challenge. We report here a study of biofilm formation of S. epidermidis on solid surfaces using a combination of confocal laser scanning (CLSM) and atomic force microscopy (AFM) in both air and aqueous environments. We have investigated the inhibitory effects of surfaces treated with four organic compounds, two benzoate derivatives denoted as compound 59 and 75 and two carboxamide derivatives denoted as compound 47 and 73, on S. epidermidis adhesion and biofilm formation. All four compounds evoke significant inhibitory effects on the formation of S. epidermidis biofilms with compounds 47 and 73 being most effective. None of the compounds were found to inhibit growth of S. epidermidis in liquid cultures. Bacteria attached to the substrate when exposed to the compounds were not affected indicating that these compounds inhibit initial adhesion. These results suggest a pretreatment for medically implanted surfaces that can prevent the biofilm formation and reduce infection.

  18. AI-2 of Aggregatibacter actinomycetemcomitans Inhibits Candida albicans Biofilm Formation

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    Endang W. Bachtiar

    2014-07-01

    Full Text Available Aggregatibacter actinomycetemcomitans, a Gram-negative bacterium, and Candida albicans, a polymorphic fungus, are both commensals of the oral cavity but both are opportunistic pathogens that can cause oral diseases. A. actinomycetemcomitans produces a quorum-sensing molecule called autoinducer-2 (AI-2, synthesized by LuxS, that plays an important role in expression of virulence factors, in intra- but also in interspecies communication. The aim of this study was to investigate the role of AI-2 based signaling in the interactions between C. albicans and A. actinomycetemcomitans. A. actinomycetemcomitans adhered to C. albicans and inhibited biofilm formation by means of a molecule that was secreted during growth. C. albicans biofilm formation increased significantly when co-cultured with A. actinomycetemcomitans luxS, lacking AI-2 production. Addition of wild-type-derived spent medium or synthetic AI-2 to spent medium of the luxS strain, restored inhibition of C. albicans biofilm formation to wild-type levels. Addition of synthetic AI-2 significantly inhibited hypha formation of C. albicans possibly explaining the inhibition of biofilm formation. AI-2 of A. actinomycetemcomitans is synthesized by LuxS, accumulates during growth and inhibits C. albicans hypha- and biofilm formation. Identifying the molecular mechanisms underlying the interaction between bacteria and fungi may provide important insight into the balance within complex oral microbial communities.

  19. Synergistic inhibition of Streptococcal biofilm by ribose and xylitol.

    Science.gov (United States)

    Lee, Heon-Jin; Kim, Se Chul; Kim, Jinkyung; Do, Aejin; Han, Se Yeong; Lee, Bhumgey David; Lee, Hyun Ho; Lee, Min Chan; Lee, So Hui; Oh, Taejun; Park, Sangbin; Hong, Su-Hyung

    2015-02-01

    Streptococcus mutans and Streptococcus sobrinus are the major causative agents of human dental caries. Therefore, the removal or inhibition of these streptococcal biofilms is essential for dental caries prevention. In the present study, we evaluated the effects of ribose treatment alone or in combination with xylitol on streptococcal biofilm formation for both species. Furthermore, we examined the expression of genes responsible for dextran-dependent aggregation (DDAG). In addition, we investigated whether ribose affects the biofilm formation of xylitol-insensitive streptococci, which results from long-term exposure to xylitol. The viability of streptococci biofilms formed in a 24-well polystyrene plate was quantified by fluorescent staining with the LIVE/DEAD bacterial viability and counting kit, which was followed by fluorescence activated cell sorting analysis. The effects of ribose and/or xylitol on the mRNA expression of DDAG-responsible genes, gbpC and dblB, was evaluated by RT-qPCR. Our data showed that ribose and other pentose molecules significantly inhibited streptococcal biofilm formation and the expression of DDAG-responsible genes. In addition, co-treatment with ribose and xylitol decreased streptococcal biofilm formation to a further extent than ribose or xylitol treatment alone in both streptococcal species. Furthermore, ribose attenuated the increase of xylitol-insensitive streptococcal biofilm, which results in the reduced difference of biofilm formation between S. mutans that are sensitive and insensitive to xylitol. These data suggest that pentose may be used as an additive for teeth-protective materials or in sweets. Furthermore, ribose co-treatment with xylitol might help to increase the anti-cariogenic efficacy of xylitol. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Streptococcus suis Serotype 2 Biofilms Inhibit the Formation of Neutrophil Extracellular Traps.

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    Ma, Fang; Yi, Li; Yu, Ningwei; Wang, Guangyu; Ma, Zhe; Lin, Huixing; Fan, Hongjie

    2017-01-01

    Invasive infections caused by Streptococcus suis serotype 2 (SS2) has emerged as a clinical problem in recent years. Neutrophil extracellular traps (NETs) are an important mechanism for the trapping and killing of pathogens that are resistant to phagocytosis. Biofilm formation can protect bacteria from being killed by phagocytes. Until now, there have only been a few studies that focused on the interactions between bacterial biofilms and NETs. SS2 in both a biofilm state and a planktonic cell state were incubated with phagocytes and NETs, and bacterial survival was assessed. DNase I and cytochalasin B were used to degrade NET DNA or suppress phagocytosis, respectively. Extracellular DNA was stained with impermeable fluorescent dye to quantify NET formation. Biofilm formation increased up to 6-fold in the presence of neutrophils, and biofilms were identified in murine tissue. Both planktonic and biofilm cells induced neutrophils chemotaxis to the infection site, with neutrophils increasing by 85.1 and 73.8%, respectively. The bacteria in biofilms were not phagocytized. The bactericidal efficacy of NETs on the biofilms and planktonic cells were equal; however, the biofilm extracellular matrix can inhibit NET release. Although biofilms inhibit NETs release, NETs appear to be an important mechanism to eliminate SS2 biofilms. This knowledge advances the understanding of biofilms and may aid in the development of treatments for persistent infections with a biofilm component.

  1. Essential oil of Curcuma longa inhibits Streptococcus mutans biofilm formation.

    Science.gov (United States)

    Lee, Kwang-Hee; Kim, Beom-Su; Keum, Ki-Suk; Yu, Hyeon-Hee; Kim, Young-Hoi; Chang, Byoung-Soo; Ra, Ji-Young; Moon, Hae-Dalma; Seo, Bo-Ra; Choi, Na-Young; You, Yong-Ouk

    2011-01-01

    Curcuma longa (C. longa) has been used as a spice in foods and as an antimicrobial in Oriental medicine. In this study, we evaluated the inhibitory effects of an essential oil isolated from C. longa on the cariogenic properties of Streptococcus mutans (S. mutans), which is an important bacterium in dental plaque and dental caries formation. First, the inhibitory effects of C. longa essential oil on the growth and acid production of S. mutans were tested. Next, the effect of C. longa essential oil on adhesion to saliva-coated hydroxyapatite beads (S-HAs) was investigated. C. longa essential oil inhibited the growth and acid production of S. mutans at concentrations from 0.5 to 4 mg/mL. The essential oil also exhibited significant inhibition of S. mutans adherence to S-HAs at concentrations higher than 0.5 mg/mL. S. mutans biofilm formation was determined by scanning electron microscopy (SEM) and safranin staining. The essential oil of C. longa inhibited the formation of S. mutans biofilms at concentrations higher than 0.5 mg/mL. The components of C. longa essential oil were then analyzed by GC and GC-MS, and the major components were α-turmerone (35.59%), germacrone (19.02%), α-zingiberene (8.74%), αr-turmerone (6.31%), trans-β-elemenone (5.65%), curlone (5.45%), and β-sesquiphellandrene (4.73%). These results suggest that C. longa may inhibit the cariogenic properties of S. mutans. © 2011 Institute of Food Technologists®

  2. Fresh garlic extract inhibits Staphylococcus aureus biofilm formation under chemopreventive and chemotherapeutic conditions

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    Panan Ratthawongjirakul

    2016-08-01

    Full Text Available Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA are the leading aetiological pathogens of nosocomial infections worldwide. These bacteria form biofilms on both biotic and abiotic surfaces causing biofilm-associated infections. Within the biofilm, these bacteria might develop persistent and antimicrobial resistant characteristics resulting in chronic infections and treatment failures. Garlic exhibits broad pharmaceutical properties and inhibitory activities against S. aureus. We investigated the effects of aqueous fresh garlic extract on biofilm formation in S. aureus ATCC25923 and MRSA strains under chemopreventive and chemotherapeutic conditions. The viable bacteria and biofilm levels were quantified through colony count and crystal violet staining, respectively. The use of fresh garlic extract under both conditions significantly inhibited biofilm formation in S. aureus strains ATCC25923 and MRSA. Garlic could be developed as either a prophylactic or therapeutic agent to manage S. aureus biofilm-associated infections.

  3. Inhibition strategies of Listeria monocytogenes biofilms-current knowledge and future outlooks.

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    Oloketuyi, Sandra F; Khan, Fazlurrahman

    2017-09-01

    There is an increasing trend in the food industry on the Listeria monocytogenes biofilm formation and inhibition. This is attributed to its easy survival on contact surfaces, resistance to disinfectants or antibiotics and growth under the stringent condition used for food processing and preservation thereby leading to food contamination products by direct or indirect exposure. Though, there is a lack of conclusive evidences about the mechanism of biofilm formation, in this review, the concept of biofilm formation and various chemical, physical, and green technology approaches to prevent or control the biofilm formed is discussed. State-of-the-art approaches ranging from the application of natural to synthetic molecules with high effectiveness and non-toxicity targeted at the different steps of biofilm formation could positively influence the biofilm inhibition in the future. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Inhibition of Staphylococcus epidermidis Biofilm Formation by Traditional Thai Herbal Recipes Used for Wound Treatment

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    S. Chusri

    2012-01-01

    Full Text Available Development of biofilm is a key mechanism involved in Staphylococcus epidermidis virulence during device-associated infections. We aimed to investigate antibiofilm formation and mature biofilm eradication ability of ethanol and water extracts of Thai traditional herbal recipes including THR-SK004, THR-SK010, and THR-SK011 against S. epidermidis. A biofilm forming reference strain, S. epidermidis ATCC 35984 was employed as a model for searching anti-biofilm agents by MTT reduction assay. The results revealed that the ethanol extract of THR-SK004 (THR-SK004E could inhibit the formation of S. epidermidis biofilm on polystyrene surfaces. Furthermore, treatments with the extract efficiently inhibit the biofilm formation of the pathogen on glass surfaces determined by scanning electron microscopy and crystal violet staining. In addition, THR-SK010 ethanol extract (THR-SK010E; 0.63–5 μg/mL could decrease 30 to 40% of the biofilm development. Almost 90% of a 7-day-old staphylococcal biofilm was destroyed after treatment with THR-SK004E (250 and 500 μg/mL and THR-SK010E (10 and 20 μg/mL for 24 h. Therefore, our results clearly demonstrated THR-SK004E could prevent the staphylococcal biofilm development, whereas both THR-SK004E and THR-SK010E possessed remarkable eradication ability on the mature staphylococcal biofilm.

  5. Inhibition of Staphylococcus epidermidis Biofilm Formation by Traditional Thai Herbal Recipes Used for Wound Treatment.

    Science.gov (United States)

    Chusri, S; Sompetch, K; Mukdee, S; Jansrisewangwong, S; Srichai, T; Maneenoon, K; Limsuwan, S; Voravuthikunchai, S P

    2012-01-01

    Development of biofilm is a key mechanism involved in Staphylococcus epidermidis virulence during device-associated infections. We aimed to investigate antibiofilm formation and mature biofilm eradication ability of ethanol and water extracts of Thai traditional herbal recipes including THR-SK004, THR-SK010, and THR-SK011 against S. epidermidis. A biofilm forming reference strain, S. epidermidis ATCC 35984 was employed as a model for searching anti-biofilm agents by MTT reduction assay. The results revealed that the ethanol extract of THR-SK004 (THR-SK004E) could inhibit the formation of S. epidermidis biofilm on polystyrene surfaces. Furthermore, treatments with the extract efficiently inhibit the biofilm formation of the pathogen on glass surfaces determined by scanning electron microscopy and crystal violet staining. In addition, THR-SK010 ethanol extract (THR-SK010E; 0.63-5 μg/mL) could decrease 30 to 40% of the biofilm development. Almost 90% of a 7-day-old staphylococcal biofilm was destroyed after treatment with THR-SK004E (250 and 500 μg/mL) and THR-SK010E (10 and 20 μg/mL) for 24 h. Therefore, our results clearly demonstrated THR-SK004E could prevent the staphylococcal biofilm development, whereas both THR-SK004E and THR-SK010E possessed remarkable eradication ability on the mature staphylococcal biofilm.

  6. Inhibition and Inactivation of Uropathogenic Escherichia coli Biofilms on Urinary Catheters by Sodium Selenite

    Directory of Open Access Journals (Sweden)

    Amoolya Narayanan

    2018-06-01

    Full Text Available Urinary tract infections (UTI are the most common hospital-acquired infections in humans and are caused primarily by uropathogenic Escherichia coli (UPEC. Indwelling urinary catheters become encrusted with UPEC biofilms that are resistant to common antibiotics, resulting in chronic infections. Therefore, it is important to control UPEC biofilms on catheters to reduce the risk for UTIs. This study investigated the efficacy of selenium for inhibiting and inactivating UPEC biofilms on urinary catheters. Urinary catheters were inoculated with UPEC and treated with 0 and 35 mM selenium at 37 °C for 5 days for the biofilm inhibition assay. In addition, catheters with preformed UPEC biofilms were treated with 0, 45, 60, and 85 mM selenium and incubated at 37 °C. Biofilm-associated UPEC counts on catheters were enumerated on days 0, 1, 3, and 5 of incubation. Additionally, the effect of selenium on exopolysacchride (EPS production and expression of UPEC biofilm-associated genes was evaluated. Selenium at 35 mM concentration was effective in preventing UPEC biofilm formation on catheters compared to controls (p < 0.05. Further, this inhibitory effect was associated with a reduction in EPS production and UPEC gene expression. Moreover, at higher concentrations, selenium was effective in inactivating preformed UPEC biofilms on catheters as early as day 3 of incubation. Results suggest that selenium could be potentially used in the control of UPEC biofilms on urinary catheters.

  7. Kaempferol Inhibits the Primary Attachment Phase of Biofilm Formation in Staphylococcus aureus.

    Science.gov (United States)

    Ming, Di; Wang, Dacheng; Cao, Fengjiao; Xiang, Hua; Mu, Dan; Cao, Junjie; Li, Bangbang; Zhong, Ling; Dong, Xiaoyun; Zhong, Xiaobo; Wang, Lin; Wang, Tiedong

    2017-01-01

    The ability to form biofilms on surfaces makes Staphylococcus aureus the main pathogenic factor in implanted medical device infections. The aim of this study was to discover a biofilm inhibitor distinct from the antibiotics used to prevent infections resulting from S. aureus biofilms. Here, we describe kaempferol, a small molecule with anti-biofilm activity that specifically inhibited the formation of S. aureus biofilms. Crystal violet (CV) staining and fluorescence microscopy clearly showed that 64 μg/ml kaempferol inhibited biofilm formation by 80%. Meanwhile, the minimum inhibitory concentration (MIC) and growth curve results indicated that kaempferol had no antibacterial activity against the tested bacterial strain. Kaempferol inhibited the primary attachment phase of biofilm formation, as determined by a fibrinogen-binding assay. Moreover, a fluorescence resonance energy transfer (FRET) assay and quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) analyses revealed that kaempferol reduced the activity of S. aureus sortaseA (SrtA) and the expression of adhesion-related genes. Based on these results, kaempferol provides a starting point for the development of novel anti-biofilm drugs, which may decrease the risk of bacterial drug resistance, to prevent S. aureus biofilm-related infections.

  8. AzaSite® inhibits Staphylococcus aureus and coagulase-negative Staphylococcus biofilm formation in vitro.

    Science.gov (United States)

    Wu, Eric C; Kowalski, Regis P; Romanowski, Eric G; Mah, Francis S; Gordon, Y Jerold; Shanks, Robert M Q

    2010-12-01

    The aim of this study was to analyze the effect of azithromycin (AZM) 1% ophthalmic solution in DuraSite® (AzaSite®) on biofilm formation by Staphylococcus aureus and coagulase-negative staphylococci in vitro. Susceptible and resistant clinical strains (n = 8) of S. aureus and coagulase-negative staphylococci were challenged with serial dilutions of AzaSite® and its components: AZM, benzalkonium chloride (BAK), and the DuraSite drug delivery vehicle. After 20 h of incubation, bacterial growth was quantified using a spectrophotometer (A = 600 nm). Plates were stained with crystal violet and biofilm formation was quantified spectrophotometrically at A = 590 nm. AzaSite® and AZM inhibited bacterial growth (P reduction in biofilm formation (P reduction in biofilm formation at concentrations from 1.25 to 10 mg/mL in most strains. DuraSite® inhibited biofilm formation at concentrations between 10% and 2.5% in all studied strains (P < 0.05), without affecting bacterial growth. BAK inhibited bacterial growth and biofilm formation in all strains between concentrations of 0.042 and 0.375 mg/mL (P < 0.05). AzaSite®, AZM, or BAK prevented biofilm formation by inhibiting growth of AZM-susceptible strains. AzaSite®, AZM, and DuraSite® also reduced biofilm formation at subinhibitory concentrations for growth. Our data indicate that AZM has a moderate inhibitory effect on biofilm formation, whereas DuraSite® appears to play a greater role in the inhibition of staphylococcal biofilm formation by AzaSite®.

  9. Lipopeptide biosurfactants from Paenibacillus polymyxa inhibit single and mixed species biofilms.

    Science.gov (United States)

    Quinn, Gerry A; Maloy, Aaron P; McClean, Stephen; Carney, Brian; Slater, John W

    2012-01-01

    Although biofilms are recognised as important in microbial colonisation, solutions to their inhibition are predominantly based on planktonic assays. These solutions have limited efficacy against biofilms. Here, a series of biofilm-orientated tests were used to identify anti-biofilm compounds from marine micro-flora. This led to the isolation of a complex of anti-biofilm compounds from an extract of Paenibacillus polymyxa (PPE). A combination of rpHPLC and mass spectrometry identified the principle components of PPE as fusaricidin B (LI-FO4b) and polymyxin D1, with minor contributions from surfactins. This complex (PPE) reduced the biofilm biomass of Bacillus subtilis, Micrococcus luteus, Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus bovis. In contrast, ampicillin was only effective against S. aureus. PPE also inhibited a self-assembling marine biofilm (SAMB) in co-incubation assays by 99.3% ± 1.9 and disrupted established SAMB by 72.4% ± 4.4, while ampicillin showed no significant reduction. The effectiveness of this complex of lipopeptides against single and multispecies biofilms suggests a future role in biofilm prevention strategies.

  10. Biofilm Filtrates of Pseudomonas aeruginosa Strains Isolated from Cystic Fibrosis Patients Inhibit Preformed Aspergillus fumigatus Biofilms via Apoptosis.

    Science.gov (United States)

    Shirazi, Fazal; Ferreira, Jose A G; Stevens, David A; Clemons, Karl V; Kontoyiannis, Dimitrios P

    2016-01-01

    Pseudomonas aeruginosa (Pa) and Aspergillus fumigatus (Af) colonize cystic fibrosis (CF) patient airways. Pa culture filtrates inhibit Af biofilms, and Pa non-CF, mucoid (Muc-CF) and nonmucoid CF (NMuc-CF) isolates form an ascending inhibitory hierarchy. We hypothesized this activity is mediated through apoptosis induction. One Af and three Pa (non-CF, Muc-CF, NMuc-CF) reference isolates were studied. Af biofilm was formed in 96 well plates for 16 h ± Pa biofilm filtrates. After 24 h, apoptosis was characterized by viability dye DiBAc, reactive oxygen species (ROS) generation, mitochondrial membrane depolarization, DNA fragmentation and metacaspase activity. Muc-CF and NMuc-CF filtrates inhibited and damaged Af biofilm (pbiofilms (3.7- fold) compared to treatment with filtrates from Muc-CF- (2.5- fold) or non-CF Pa (1.7- fold). Depolarization of mitochondrial potential was greater upon exposure to NMuc-CF (2.4-fold) compared to Muc-CF (1.8-fold) or non-CF (1.25-fold) (pbiofilm, compared to control, mediated by metacaspase activation. In conclusion, filtrates from CF-Pa isolates were more inhibitory against Af biofilms than from non-CF. The apoptotic effect involves mitochondrial membrane damage associated with metacaspase activation.

  11. Inhibition and dispersal of Agrobacterium tumefaciens biofilms by a small diffusible Pseudomonas aeruginosa exoproduct(s).

    Science.gov (United States)

    Hibbing, Michael E; Fuqua, Clay

    2012-06-01

    Environmental biofilms often contain mixed populations of different species. In these dense communities, competition between biofilm residents for limited nutrients such as iron can be fierce, leading to the evolution of competitive factors that affect the ability of competitors to grow or form biofilms. We have discovered a compound(s) present in the conditioned culture fluids of Pseudomonas aeruginosa that disperses and inhibits the formation of biofilms produced by the facultative plant pathogen Agrobacterium tumefaciens. The inhibitory activity is strongly induced when P. aeruginosa is cultivated in iron-limited conditions, but it does not function through iron sequestration. In addition, the production of the biofilm inhibitory activity is not regulated by the global iron regulatory protein Fur, the iron-responsive extracytoplasmic function σ factor PvdS, or three of the recognized P. aeruginosa quorum-sensing systems. In addition, the compound(s) responsible for the inhibition and dispersal of A. tumefaciens biofilm formation is likely distinct from the recently identified P. aeruginosa dispersal factor, cis-2-decenoic acid (CDA), as dialysis of the culture fluids showed that the inhibitory compound was larger than CDA and culture fluids that dispersed and inhibited biofilm formation by A. tumefaciens had no effect on biofilm formation by P. aeruginosa.

  12. Minocycline Inhibits Candida albicans Budded-to-Hyphal-Form Transition and Biofilm Formation.

    Science.gov (United States)

    Kurakado, Sanae; Takatori, Kazuhiko; Sugita, Takashi

    2017-09-25

    Candida albicans frequently causes bloodstream infections; its budded-to-hyphalform transition (BHT) and biofilm formation are major contributors to virulence. During an analysis of antibacterial compounds that inhibit C. albicans BHT, we found that the tetracycline derivative minocycline inhibited BHT and subsequent biofilm formation. Minocycline decreased expression of hypha-specific genes HWP1 and ECE1, and adhesion factor gene ALS3 of C. albicans. In addition, minocycline decreased cell surface hydrophobicity and the extracellular β-glucan level in biofilms. Minocycline has been widely used for catheter antibiotic lock therapy to prevent bacterial infection; this compound may also be prophylactically effective against Candida infection.

  13. Clotrimazole and econazole inhibit Streptococcus mutans biofilm and virulence in vitro.

    Science.gov (United States)

    Qiu, Wei; Ren, Biao; Dai, Huanqin; Zhang, Lixin; Zhang, Qiong; Zhou, Xuedong; Li, Yuqing

    2017-01-01

    The aim of this study was to determine the inhibitory effect of eight antifungal drugs on S. mutans growth, biofilm formation and virulence factors. The actions of antifungal drugs on S. mutans were determined by recovery plates and survival kinetic curves. Biofilms were observed by scanning electron microscopy and the viable cells were recovered on BHI plates, meanwhile biofilms were stained by BacLight live/dead kit to investigate the biofilm viability. Bacteria/extracellular polysaccharides staining assays were performed to determine the EPS production of S. mutans biofilms. Acidogenicity and acidurity of S. mutans were determined using pH drop and acid tolerance assays, and the expression of ldh gene was evaluated using qPCR. We found that clotrimazole (CTR) and econazole (ECO) showed antibacterial activities on S. mutans UA159 and S. mutans clinical isolates at 12.5 and 25mg/L, respectively. CTR and ECO could also inhibit S. mutans biofilm formation and reduce the viability of preformed biofilm. CTR and ECO affected the live/dead ratio and the EPS/bacteria ratio of S. mutans biofilms. CTR and ECO also inhibited the pH drop, lactate acid production, and acid tolerance. The abilities of CTR and ECO to inhibit S. mutans ldh expression were also confirmed. We found that two antifungal azoles, CTR and ECO, had the abilities to inhibit the growth and biofilm formation of S. mutans and more importantly, they could also inhibit the virulence factors of S. mutans. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Biofilms.

    Science.gov (United States)

    López, Daniel; Vlamakis, Hera; Kolter, Roberto

    2010-07-01

    The ability to form biofilms is a universal attribute of bacteria. Biofilms are multicellular communities held together by a self-produced extracellular matrix. The mechanisms that different bacteria employ to form biofilms vary, frequently depending on environmental conditions and specific strain attributes. In this review, we emphasize four well-studied model systems to give an overview of how several organisms form biofilms: Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus. Using these bacteria as examples, we discuss the key features of biofilms as well as mechanisms by which extracellular signals trigger biofilm formation.

  15. Organic compounds inhibiting S. epidermidis adhesion and biofilm formation

    DEFF Research Database (Denmark)

    Qin, Zhiqiang; Zhang, Jingdong; Hu, Yifan

    2009-01-01

    The formation of biofilms on surfaces of indwelling medical devices is a serious medical problem. Staphylococcus epidermidis is a common pathogen found to colonize implanted devices and as a biofilm is more resistant to the host immune system as well as to antibiotic treatments. Combating S....... epidermidis infections by preventing or eradicating biofilm formation of the bacterium is therefore a medically important challenge. We report here a study of biofilm formation of S. epidermidis on solid surfaces using a combination of confocal laser scanning (CLSM) and atomic force microscopy (AFM) in both...... air and aqueous environments. We have investigated the inhibitory effects of surfaces treated with four organic compounds, two benzoate derivatives denoted as compound 59 and 75 and two carboxamicle derivatives denoted as compound 47 and 73, on S. epidermidis adhesion and biofilm formation. All four...

  16. Streptococcus oligofermentans Inhibits Streptococcus mutans in Biofilms at Both Neutral pH and Cariogenic Conditions.

    Science.gov (United States)

    Bao, Xudong; de Soet, Johannes Jacob; Tong, Huichun; Gao, Xuejun; He, Libang; van Loveren, Cor; Deng, Dong Mei

    2015-01-01

    Homeostasis of oral microbiota can be maintained through microbial interactions. Previous studies showed that Streptococcus oligofermentans, a non-mutans streptococci frequently isolated from caries-free subjects, inhibited the cariogenic Streptococcus mutans by the production of hydrogen peroxide (HP). Since pH is a critical factor in caries formation, we aimed to study the influence of pH on the competition between S. oligofermentans and S. mutans in biofilms. To this end, S. mutans and S. oligofermentans were inoculated alone or mixed at 1:1 ratio in buffered biofilm medium in a 96-well active attachment model. The single- and dual-species biofilms were grown under either constantly neutral pH or pH-cycling conditions. The latter includes two cycles of 8 h neutral pH and 16 h pH 5.5, used to mimic cariogenic condition. The 48 h biofilms were analysed for the viable cell counts, lactate and HP production. The last two measurements were carried out after incubating the 48 h biofilms in buffers supplemented with 1% glucose (pH 7.0) for 4 h. The results showed that S. oligofermentans inhibited the growth of S. mutans in dual-species biofilms under both tested pH conditions. The lactic acid production of dual-species biofilms was significantly lower than that of single-species S. mutans biofilms. Moreover, dual-species and single-species S. oligofermentans biofilms grown under pH-cycling conditions (with a 16 h low pH period) produced a significantly higher amount of HP than those grown under constantly neutral pH. In conclusion, S. oligofermentans inhibited S. mutans in biofilms not only under neutral pH, but also under pH-cycling conditions, likely through HP production. S. oligofermentans may be a compelling probiotic candidate against caries.

  17. The efficacy of sarang semut extract (Myrmecodia pendens Merr & Perry in inhibiting Porphyromonas gingivalis biofilm formation

    Directory of Open Access Journals (Sweden)

    Zulfan M. Alibasyah

    2017-06-01

    Full Text Available Background: Porphyromonas gingivalis (P. gingivalis is a pathogenic bacteria present in the oral cavity involved in the pathogenesis of chronic periodontitis and biofilm. This mass of microorganisms represents one of the virulent factors of P. gingivalis which plays an important role as an attachment initiator in host cells. Sarang semut is a natural material possessing the ability to inhibit the growth of P. gingivalis. Purpose: This study aims to analyze the effect of sarang semut extract on the formation of P. gingivalis biofilm. Methods: The study used methanol sarang semut extract and P. gingivalis ATCC 33277 and phosphomycin as a positive control. Treatment was initiated by means of culturing. Biofilm test and P. gingivalis biofilm formation observation were subsequently performed by means of a light microscope at a magnification of 400x. Results: The formation of P. gingivalis biofilms tended to increase at 3, 6, and 9 hours. Results of the violet crystal test showed that concentrations of 100% and 75% of the sarang semut extract successfully inhibited the formation of P. gingivalis biofilm according to the incubation time. Meanwhile, the sarang semut extracts at concentrations of 50%, 25%, 12.5%, and 6.125% resulted in weak inhibition of the formation of P. gingivalis biofilm. The biofilm mass profile observed by a microscope tended to decrease as an indicator of the effects of the sarang semut extract. Conclusion: Sarang semut extract can inhibit the formation of P. gingivalis biofilm, especially at concentrations of 100% and 75%. Nevertheless, phosphomycin has stronger antibiofilm of P. gingivalis effects than those of the sarang semut extract at all of the concentrations listed above.

  18. Biofilms

    OpenAIRE

    López, Daniel; Vlamakis, Hera; Kolter, Roberto

    2010-01-01

    The ability to form biofilms is a universal attribute of bacteria. Biofilms are multicellular communities held together by a self-produced extracellular matrix. The mechanisms that different bacteria employ to form biofilms vary, frequently depending on environmental conditions and specific strain attributes. In this review, we emphasize four well-studied model systems to give an overview of how several organisms form biofilms: Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and ...

  19. Histidine Metabolism and IGPD Play a Key Role in Cefquinome Inhibiting Biofilm Formation of Staphylococcus xylosus

    Directory of Open Access Journals (Sweden)

    Yong-hui Zhou

    2018-04-01

    Full Text Available Staphylococcus xylosus (S. xylosus is an AT-rich and coagulase-negative Staphylococcus (CNS. It is normally regarded as non-pathogenic, however, recent studies have demonstrated that it is related to human opportunistic infections and bovine mastitis. In addition, S. xylosus strains have the ability to form biofilm. Biofilms are also involved in chronic infections and antibiotic resistance, there are only a few reports about cefquinome inhibiting S. xylosus biofilm formation and the protein targets of cefquinome. In our study, we found that sub-MICs of cefquinome were sufficient to inhibit biofilm formation. To investigate the potential protein targets of cefquinome, we used iTRAQ for the analyses of cells at two different conditions: 1/2-MIC (0.125 μg/mL cefquinome treatment and no treatment. Using iTRAQ technique and KEGG database analysis, we found that proteins differently expression in histidine metabolism pathway may play a role in the process by which 1/2-MIC (0.125 μg/mL cefquinome inhibits S. xylosus biofilm formation. Interestingly, we found a sharply down-regulated enzyme [A0A068E9J3 imidazoleglycerol-phosphate dehydratase (IGPD] involved in histidine metabolism pathway in cefquinome-treated cells. We demonstrated the important role of IGPD in sub-MICs cefquinome inhibiting biofilm formation of S. xylosus by gene (hisB knockout, IGPD enzyme activity and histidine content assays. Thus, our data sheds light on important role of histidine metabolism in S. xylosus biofilm formation; especially, IGPD involved in histidine metabolism might play a crucial role in sub-MICs cefquinome inhibition of biofilm formation of S. xylosus, and we propose IGPD as an attractive protein target of cefquinome.

  20. Chitosanase purified from bacterial isolate Bacillus licheniformis of ruined vegetables displays broad spectrum biofilm inhibition.

    Science.gov (United States)

    Muslim, Sahira Nsayef; Al-Kadmy, Israa M S; Hussein, Nadheema Hammood; Mohammed Ali, Alaa Naseer; Taha, Buthainah Mohammed; Aziz, Sarah Naji; Kheraif, Abdulaziz Abdullah Al; Divakar, Darshan Devang; Ramakrishnaiah, Ravikumar

    2016-11-01

    A number of bacterial species produces chitosanases which has variety of applications because of its high biodegradability, non-toxicity and antimicrobial assets. In the present study chitosanase is purified from new bacterial species Bacillus licheniformis from spoiled vegetable. This novel strain of Bacillus licheniformis isolated from spoilt cucumber and pepper samples has the ability to produce the chitosanase enzyme when grown on chitosan substrate. Study also examined its antibiofilm properties against diverse bacterial species with biofilm forming ability. The purified chitosanase inhibited the biofilm formation ability for all Gram-negative and Gram-positive biofilm-forming bacteria [biofilm producers] tested in this study in congo red agar and microtiter plate's methods. Highly antibiofilm activity of chitosanase was recorded against Pseudomonas aeruginosa followed by Klebsiella pneumoniae with reduction of biofilm formation upto 22 and 29%, respectively compared with [100] % of control. Biofilm formation has multiple role including ability to enhance resistance and self-protection from external stress. This chitosanase has promising benefit as antibiofilm agent against biofilm forming pathogenic bacteria and has promising application as alternative antibiofilm agents to combat the growing number of multidrug resistant pathogen-associated infections, especially in situation where biofilms are involved. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Inhibition of Adherence of Mycobacterium avium to Plumbing Surface Biofilms of Methylobacterium spp.

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    Mari Carmen Muñoz Egea

    2017-09-01

    Full Text Available Both Mycobacterium spp. and Methylobacterium spp. are opportunistic premise plumbing pathogens that are found on pipe surfaces in households. However, examination of data published in prior microbiological surveys indicates that Methylobacterium spp. and Mycobacterium spp. tend not to coexist in the same household plumbing biofilms. That evidence led us to test the hypothesis that Methylobacterium spp. in biofilms could inhibit the adherence of Mycobacterium avium. Measurements of adherence of M. avium cells to stainless steel coupons using both culture and PCR-based methods showed that the presence of Methylobacterium spp. biofilms substantially reduced M. avium adherence and vice versa. That inhibition of M. avium adherence was not reduced by UV-irradiation, cyanide/azide exposure, or autoclaving of the Methylobacterium spp. biofilms. Further, there was no evidence of the production of anti-mycobacterial compounds by biofilm-grown Methylobacterium spp. cells. The results add to understanding of the role of microbial interactions in biofilms as a driving force in the proliferation or inhibition of opportunistic pathogens in premise plumbing, and provide a potential new avenue by which M. avium exposures may be reduced for at-risk individuals.

  2. Biofilm inhibition activity of compounds isolated from two Eunicea species collected at the Caribbean Sea

    Directory of Open Access Journals (Sweden)

    Yenny Martínez Díaz

    Full Text Available Abstract Biofilm has a primary role in the pathogenesis of diseases and in the attachment of multicellular organisms to a fouled surface. Because of that, the control of bacterial biofilms has been identified as an important target. In the present study, five lipid compounds isolated from soft coral Eunicea sp. and three terpenoids together with a mixture of sterols from Eunicea fusca collected at the Colombian Caribbean Sea showed different effectiveness against biofilm formation by three marine bacteria associated with immersed fouled surfaces, Ochrobactrum pseudogringnonense,Alteromona macleodii and Vibrio harveyi, and against two known biofilm forming bacteria, Pseudomonas aeruginosa ATCC 27853 and Staphylococcus aureus ATCC 25923. The pure compounds were characterized by NMR, HRESI-MS, HRGC-MS and optical rotation. The most effective compounds were batyl alcohol (1 and fuscoside E peracetate (6, acting against four strains without affecting their microbial growth. Compound 1 showed biofilm inhibition greater than 30% against A. macleodii, and up to 60% against O. pseudogringnonense,V. harveyi and S. aureus. Compound 6 inhibited O. pseudogringnonense and V. harveyi between 25 and 50%, and P. aeruginosa or S. aureus up to 60% at 0.5 mg/ml. The results suggest that these compounds exhibit specific biofilm inhibition with lower antimicrobial effect against the bacterial species assayed.

  3. Inhibition of Serratia marcescens Smj-11 biofilm formation by Alcaligenes faecalis STN17 crude extract

    International Nuclear Information System (INIS)

    Lutfi, Zainal; Ahmad, Asmat; Usup, Gires

    2014-01-01

    Serratia marcescens biofilms are formed when they are bound to surfaces in aqueous environments. S. marcescens utilizes N-acylhomoserine lactone (AHL) as its quorum sensing signal molecule. The accumulation of AHL indicates the bacteria to produce matrices to form biofilms. Prodigiosin (2-methyl-3-pentyl-6-methoxyprodigiosin), which causes red pigmentation in the colonies, are also produced when the AHL reaches a certain threshold. The Alcaligenes faecalis STN17 crude extract is believed to inhibit quorum sensing in the S. marcescens Smj-11 and, thus, impedes its biofilm formation ability. A. faecalis STN17 was grown in marine broth, and ethyl acetate extraction was carried out. The crude compound of A. faecalis STN17 was diluted at high concentration (0.2-6.4 mg/mL) and was taken to confirm anti-biofilm activity through the crystal violet method in 96-wells plate. Then, the crude extract underwent purification using simple solvents partitioning test to discern the respective compounds that had the anti-biofilm activity under the crystal violet method. The crystal violet test showed that the crude did have anti-biofilm activity on S. marcescens Smj-11, but did not kill the cells. This finding signifies that the suppression of biofilm formation in S. marcescens by A. faecalis STN17 has a strong correlation. The partitioning test showed that A. faecalis STN17 crude extract has several compounds and only the compound(s) in chloroform showed activities. In conclusion, the crude extract of A. faecalis STN17 has the ability to inhibit S. marcescens Smj-11 biofilm formation

  4. Inhibition of Serratia marcescens Smj-11 biofilm formation by Alcaligenes faecalis STN17 crude extract

    Energy Technology Data Exchange (ETDEWEB)

    Lutfi, Zainal; Ahmad, Asmat [School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor (Malaysia); Usup, Gires [School of Environmental and Natural Resources Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor (Malaysia)

    2014-09-03

    Serratia marcescens biofilms are formed when they are bound to surfaces in aqueous environments. S. marcescens utilizes N-acylhomoserine lactone (AHL) as its quorum sensing signal molecule. The accumulation of AHL indicates the bacteria to produce matrices to form biofilms. Prodigiosin (2-methyl-3-pentyl-6-methoxyprodigiosin), which causes red pigmentation in the colonies, are also produced when the AHL reaches a certain threshold. The Alcaligenes faecalis STN17 crude extract is believed to inhibit quorum sensing in the S. marcescens Smj-11 and, thus, impedes its biofilm formation ability. A. faecalis STN17 was grown in marine broth, and ethyl acetate extraction was carried out. The crude compound of A. faecalis STN17 was diluted at high concentration (0.2-6.4 mg/mL) and was taken to confirm anti-biofilm activity through the crystal violet method in 96-wells plate. Then, the crude extract underwent purification using simple solvents partitioning test to discern the respective compounds that had the anti-biofilm activity under the crystal violet method. The crystal violet test showed that the crude did have anti-biofilm activity on S. marcescens Smj-11, but did not kill the cells. This finding signifies that the suppression of biofilm formation in S. marcescens by A. faecalis STN17 has a strong correlation. The partitioning test showed that A. faecalis STN17 crude extract has several compounds and only the compound(s) in chloroform showed activities. In conclusion, the crude extract of A. faecalis STN17 has the ability to inhibit S. marcescens Smj-11 biofilm formation.

  5. Inhibition effect of cashew stem bark extract (Anacardium Occidentale L. on biofilm formation of Streptococcus sanguinis

    Directory of Open Access Journals (Sweden)

    Rizni Amaliah

    2012-12-01

    Full Text Available Background: Biofilm is communities of microorganisms attached to solid surface and enclosed in extracellular matrix that protected microorganisms from antibacterial agents and host defense. One of bacteria might have a role in initial colonization of biofilm formation is Streptococcus sanguinis (S. sanguinis. Previous studies showed that cashew stem bark extract (Anacardium occidentale L. can inhibit the growth of Streptococcus strains. Purpose: The purpose of this study was to determine the inhibition effect of cashew (Anacardium occidentale L. stem bark ethanol extract on biofilm formation of S. sanguinis. Methods: Streptococcus sanguinis grown in Brain Heart Infusion (BHI + 2% sucrose medium by using microplate polystyrene 96 wells. The samples were divided into 3 groups, 5% polyethyleneglycol (PEG as negative control, cashew stem bark extract (concentration 3.125 mg/ml, 6.25 mg/ml, 9.375 mg/ml, and 12.5 mg/ml, and 0.12% chlorhexidine (as positive control. Biofilm was stained by 1% crystal violet. Afterwards, optical density (OD of samples were measured by microplate reader λ 595 nm. The data of biofilm formation inhibition percentage were analyzed by one way ANOVA and then continued by Least Significant Difference (LSD test. Results: The result of one way ANOVA showed that there were significant differences in inhibition of S. sanguinis biofilm formation (p<0.05. LSD test showed that concentration extract 3.125 mg/ml had significant difference with concentration 9.375 mg/ml and 12.5 mg/ml. Reciprocally, concentration 6.25 mg/ml had significant difference with concentration 9.375 mg/ml and 12.5 mg/ml. Conclusion: Cashew stem bark extract was able to inhibit biofilm formation of S. sanguinis.Latar belakang: Biofilm merupakan sekumpulan mikroorganisme yang melekat pada permukaan solid dan diselubungi oleh matriks ekstraseluler yang melindungi mikroorganisme dari bahan-bahan antibakteri dan sel-sel pertahanan tubuh. Salah satu bakteri yang

  6. Miltefosine inhibits Candida albicans and non-albicans Candida spp. biofilms and impairs the dispersion of infectious cells.

    Science.gov (United States)

    Vila, Taissa; Ishida, Kelly; Seabra, Sergio Henrique; Rozental, Sonia

    2016-11-01

    Candida spp. can adhere to and form biofilms over different surfaces, becoming less susceptible to antifungal treatment. Resistance of biofilms to antifungal agents is multifactorial and the extracellular matrix (ECM) appears to play an important role. Among the few available antifungals for treatment of candidaemia, only the lipid formulations of amphotericin B (AmB) and the echinocandins are effective against biofilms. Our group has previously demonstrated that miltefosine has an important effect against Candida albicans biofilms. Thus, the aim of this work was to expand the analyses of the in vitro antibiofilm activity of miltefosine to non-albicans Candida spp. Miltefosine had significant antifungal activity against planktonic cells and the development of biofilms of C. albicans, Candida parapsilosis, Candida tropicalis and Candida glabrata. The activity profile in biofilms was superior to fluconazole and was similar to that of AmB and caspofungin. Biofilm-derived cells with their ECM extracted became as susceptible to miltefosine as planktonic cells, confirming the importance of the ECM in the biofilm resistant behaviour. Miltefosine also inhibited biofilm dispersion of cells at the same concentration needed to inhibit planktonic cell growth. The data obtained in this work reinforce the potent inhibitory activity of miltefosine on biofilms of the four most pathogenic Candida spp. and encourage further studies for the utilisation of this drug and/or structural analogues on biofilm-related infections. Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

  7. Inhibition and inactivation of Salmonella typhimurium biofilms from polystyrene and stainless steel surfaces by essential oils and phenolic constituent carvacrol.

    Science.gov (United States)

    Soni, Kamlesh A; Oladunjoye, Ademola; Nannapaneni, Ramakrishna; Schilling, M Wes; Silva, Juan L; Mikel, Benjy; Bailey, R Hartford

    2013-02-01

    Persistence of Salmonella biofilms within food processing environments is an important source of Salmonella contamination in the food chain. In this study, essential oils of thyme and oregano and their antimicrobial phenolic constituent carvacrol were evaluated for their ability to inhibit biofilm formation and inactivate preformed Salmonella biofilms. A crystal violet staining assay and CFU measurements were utilized to quantify biofilm cell mass, with evaluating factors such as strain variation, essential oil type, their concentrations, exposure time, as well as biofilm formation surface. Of the three Salmonella strains, Salmonella Typhimurium ATCC 23564 and Salmonella Typhimurium ATCC 19585 produced stronger biofilms than Salmonella Typhimurium ATCC 14028. Biofilm formation by different Salmonella strains was 1.5- to 2-fold higher at 22°C than at 30 or 37°C. The presence of nonbiocidal concentrations of thyme oil, oregano oil, and phenolic carvacrol at 0.006 to 0.012% suppressed Salmonella spp. biofilm formation 2- to 4-fold, but could not completely eliminate biofilm formation. There was high correlation in terms of biofilm inactivation, as determined by the crystal violet-stained optical density (at a 562-nm wavelength) readings and the viable CFU counts. Reduction of biofilm cell mass was dependent on antimicrobial concentration. A minimum concentration of 0.05 to 0.1% of these antimicrobial agents was needed to reduce a 7-log CFU biofilm mass to a nondetectable level on both polystyrene and stainless steel surfaces within 1 h of exposure time.

  8. Combating biofilms

    DEFF Research Database (Denmark)

    Yang, Liang; Liu, Yang; Wu, Hong

    2012-01-01

    Biofilms are complex microbial communities consisting of microcolonies embedded in a matrix of self-produced polymer substances. Biofilm cells show much greater resistance to environmental challenges including antimicrobial agents than their free-living counterparts. The biofilm mode of life...... is believed to significantly contribute to successful microbial survival in hostile environments. Conventional treatment, disinfection and cleaning strategies do not proficiently deal with biofilm-related problems, such as persistent infections and contamination of food production facilities. In this review......, strategies to control biofilms are discussed, including those of inhibition of microbial attachment, interference of biofilm structure development and differentiation, killing of biofilm cells and induction of biofilm dispersion....

  9. To be or not to be planktonic? Self-inhibition of biofilm development.

    Science.gov (United States)

    Nagar, Elad; Schwarz, Rakefet

    2015-05-01

    The transition between planktonic growth and biofilm formation represents a tightly regulated developmental shift that has substantial impact on cell fate. Here, we highlight different mechanisms through which bacteria limit their own biofilm development. The mechanisms involved in these self-inhibition processes include: (i) regulation by secreted small molecules, which govern intricate signalling cascades that eventually decrease biofilm development, (ii) extracellular polysaccharides capable of modifying the physicochemical properties of the substratum and (iii) extracellular DNA that masks an adhesive structure. These mechanisms, which rely on substances produced by the bacterium and released into the extracellular milieu, suggest regulation at the communal level. In addition, we provide specific examples of environmental cues (e.g. blue light or glucose level) that trigger a cellular response reducing biofilm development. All together, we describe a diverse array of mechanisms underlying self-inhibition of biofilm development in different bacteria and discuss possible advantages of these processes. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  10. D-Tagatose inhibits the growth and biofilm formation of Streptococcus mutans

    Science.gov (United States)

    Hasibul, Khaleque; Nakayama-Imaohji, Haruyuki; Hashimoto, Masahito; Yamasaki, Hisashi; Ogawa, Takaaki; Waki, Junpei; Tada, Ayano; Yoneda, Saori; Tokuda, Masaaki; Miyake, Minoru; Kuwahara, Tomomi

    2018-01-01

    Dental caries is an important global health concern and Streptococcus mutans has been established as a major cariogenic bacterial species. Reports indicate that a rare sugar, D-tagatose, is not easily catabolized by pathogenic bacteria. In the present study, the inhibitory effects of D-tagatose on the growth and biofilm formation of S. mutans GS-5 were examined. Monitoring S. mutans growth over a 24 h period revealed that D-tagatose prolonged the lag phase without interfering with the final cell yield. This growth retardation was also observed in the presence of 1% sucrose, although it was abolished by the addition of D-fructose. S. mutans biofilm formation was significantly inhibited by growth in sucrose media supplemented with 1 and 4% D-tagatose compared with that in a culture containing sucrose alone, while S. mutans formed granular biofilms in the presence of this rare sugar. The inhibitory effect of D-tagatose on S. mutans biofilm formation was significantly more evident than that of xylitol. Growth in sucrose media supplemented with D-tagatose significantly decreased the expression of glucosyltransferase, exo-β-fructosidase and D-fructose-specific phosphotransferase genes but not the expression of fructosyltransferase compared with the culture containing sucrose only. The activity of cell-associated glucosyltransferase in S. mutans was inhibited by 4% D-tagatose. These results indicate that D-tagatose reduces water-insoluble glucan production from sucrose by inhibiting glucosyltransferase activities, which limits access to the free D-fructose released during this process and retards the growth of S. mutans. Therefore, foods and oral care products containing D-tagatose are anticipated to reduce the risk of caries by inhibiting S. mutans biofilm formation. PMID:29115611

  11. Biofilm formation and ethanol inhibition by bacterial contaminants of biofuel fermentation.

    Science.gov (United States)

    Rich, Joseph O; Leathers, Timothy D; Bischoff, Kenneth M; Anderson, Amber M; Nunnally, Melinda S

    2015-11-01

    Bacterial contaminants can inhibit ethanol production in biofuel fermentations, and even result in stuck fermentations. Contaminants may persist in production facilities by forming recalcitrant biofilms. A two-year longitudinal study was conducted of bacterial contaminants from a Midwestern dry grind corn fuel ethanol facility. Among eight sites sampled in the facility, the combined liquefaction stream and yeast propagation tank were consistently contaminated, leading to contamination of early fermentation tanks. Among 768 contaminants isolated, 92% were identified as Lactobacillus sp., with the most abundant species being Lactobacillus plantarum, Lactobacillus casei, Lactobacillus mucosae, and Lactobacillus fermentum. Seven percent of total isolates showed the ability to form biofilms in pure cultures, and 22% showed the capacity to significantly inhibit ethanol production. However, these traits were not correlated. Ethanol inhibition appeared to be related to acetic acid production by contaminants, particularly by obligately heterofermentative species such as L. fermentum and L. mucosae. Published by Elsevier Ltd.

  12. Biofilm Inhibition by Novel Natural Product- and Biocide-Containing Coatings Using High-Throughput Screening

    Directory of Open Access Journals (Sweden)

    Maria Salta

    2018-05-01

    Full Text Available The use of natural products (NPs as possible alternative biocidal compounds for use in antifouling coatings has been the focus of research over the past decades. Despite the importance of this field, the efficacy of a given NP against biofilm (mainly bacteria and diatoms formation is tested with the NP being in solution, while almost no studies test the effect of an NP once incorporated into a coating system. The development of a novel bioassay to assess the activity of NP-containing and biocide-containing coatings against marine biofilm formation has been achieved using a high-throughput microplate reader and highly sensitive confocal laser scanning microscopy (CLSM, as well as nucleic acid staining. Juglone, an isolated NP that has previously shown efficacy against bacterial attachment, was incorporated into a simple coating matrix. Biofilm formation over 48 h was assessed and compared against coatings containing the NP and the commonly used booster biocide, cuprous oxide. Leaching of the NP from the coating was quantified at two time points, 24 h and 48 h, showing evidence of both juglone and cuprous oxide being released. Results from the microplate reader showed that the NP coatings exhibited antifouling efficacy, significantly inhibiting biofilm formation when compared to the control coatings, while NP coatings and the cuprous oxide coatings performed equally well. CLSM results and COMSTAT analysis on biofilm 3D morphology showed comparable results when the NP coatings were tested against the controls, with higher biofilm biovolume and maximum thickness being found on the controls. This new method proved to be repeatable and insightful and we believe it is applicable in antifouling and other numerous applications where interactions between biofilm formation and surfaces is of interest.

  13. Biofilm inhibition activity of traditional medicinal plants from Northwestern Argentina against native pathogen and environmental microorganisms

    Directory of Open Access Journals (Sweden)

    Cintia Mariana Romero

    Full Text Available Abstract: INTRODUCTION: Plants have been commonly used in popular medicine of most cultures for the treatment of disease. The in vitro antimicrobial activity of certain Argentine plants used in traditional medicine has been reported. The aim of this study was to investigate the antimicrobial, anti-biofilm, and anti-cell adherence activities of native plants (Larrea divaricata, Tagetes minuta, Tessaria absinthioides, Lycium chilense, and Schinus fasciculatus collected in northwestern Argentina. METHODS: The activities of the five plant species were evaluated in Bacillus strains and clinical strains of coagulase-negative Staphylococcus isolated from northwestern Argentina and identified by 16S rDNA. RESULT: Lycium chilense and Schinus fasciculatus were the most effective antimicrobial plant extracts (15.62µg/ml and 62.50µg/ml for Staphylococcus sp. Mcr1 and Bacillus sp. Mcn4, respectively. The highest (66% anti-biofilm activity against Bacillus sp. Mcn4 was observed with T. absinthioides and L. divaricate extracts. The highest (68% anti-biofilm activity against Staphylococcus sp. Mcr1 was observed with L. chilense extract. T. minuta, T. absinthioides, and L. divaricata showed percentages of anti-biofilm activity of between 55% and 62%. The anti-adherence effects of T. minuta and L. chilense observed in Bacillus sp. Mcn4 reflected a difference of only 22% and 10%, respectively, between anti-adherence and biofilm inhibition. Thus, the inhibition of biofilm could be related to cell adherence. In Staphylococcus sp. Mcr1, all plant extracts produced low anti-adherence percentages. CONCLUSION: These five species may represent a source of alternative drugs derived from plant extracts, based on ethnobotanical knowledge from northwest Argentina.

  14. Inhibiting effects of Streptococcus salivarius on competence-stimulating peptide-dependent biofilm formation by Streptococcus mutans.

    Science.gov (United States)

    Tamura, S; Yonezawa, H; Motegi, M; Nakao, R; Yoneda, S; Watanabe, H; Yamazaki, T; Senpuku, H

    2009-04-01

    The effects of Streptococcus salivarius on the competence-stimulating peptide (CSP)-dependent biofilm formation by Streptococcus mutans were investigated. Biofilms were grown on 96-well microtiter plates coated with salivary components in tryptic soy broth without dextrose supplemented with 0.25% sucrose. Biofilm formations were stained using safranin and quantification of stained biofilms was performed by measuring absorbance at 492 nm. S. mutans formed substantial biofilms, whereas biofilms of S. salivarius were formed poorly in the medium conditions used. Furthermore, in combination cultures, S. salivarius strongly inhibited biofilm formation when cultured with S. mutans. This inhibition occurred in the early phase of biofilm formation and was dependent on inactivation of the CSP of S. mutans, which is associated with competence, biofilm formation, and antimicrobial activity of the bacterium, and is induced by expression of the comC gene. Comparisons between the S. mutans clinical strains FSC-3 and FSC-3DeltaglrA in separate dual-species cultures with S. salivarius indicated that the presence of the bacitracin transport ATP-binding protein gene glrA caused susceptibility to inhibition of S. mutans biofilm formation by S. salivarius, and was also associated with the regulation of CSP production by com gene-dependent quorum sensing systems. It is considered that regulation of CSP by glrA in S. mutans and CSP inactivation by S. salivarius are important functions for cell-to-cell communication between biofilm bacteria and oral streptococci such as S. salivarius. Our results provide useful information for understanding the ecosystem of oral streptococcal biofilms, as well as the competition between and coexistence of multiple species in the oral cavity.

  15. Curcumin reduces Streptococcus mutans biofilm formation by inhibiting sortase A activity.

    Science.gov (United States)

    Hu, Ping; Huang, Ping; Chen, Min Wei

    2013-10-01

    Sortase A is an enzyme responsible for the covalent attachment of Pac proteins to the cell wall in Streptococcus mutans. It has been shown to play a role in modulating the surface properties and the biofilm formation and influence the cariogenicity of S. mutans. Curcumin, an active ingredient of turmeric, was reported to be an inhibitor for Staphylococcus aureus sortase A. The aim of this study was to investigate the inhibitory ability of curcumin against S. mutans sortase A and the effect of curcumin for biofilm formation. The antimicrobial activity of the curcumin to the S. mutans and inhibitory ability of the curcumin against the purified sortase A in vitro were detected. Western-blot and real-time PCR were used to analysis the sortase A mediated Pac protein changes when the S. mutans was cultured with curcumin. The curcumin on the S. mutans biofilm formation was determined by biofilm formation analysis. Curcumin can inhibit purified S. mutans sortase A with a half-maximal inhibitory concentration (IC50) of (10.2±0.7)μmol/l, which is lower than minimum inhibitory concentration (MIC) of 175μmol/l. Curcumin (15μmol/l) was found to release the Pac protein to the supernatant and reduce S. mutans biofilm formation. These results indicated that curcumin is an S. mutans sortase A inhibitor and has promising anti-caries characteristics through an anti-adhesion-mediated mechanism. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  16. Development of molecularly imprinted polymers to block quorum sensing and inhibit bacterial biofilm formation.

    Science.gov (United States)

    Ma, Luyao; Feng, Shaolong; de la Fuente-Nunez, Cesar; Hancock, Robert E W; Lu, Xiaonan

    2018-05-16

    Bacterial biofilms are responsible for most clinical infections and show increased antimicrobial resistance. In this study, molecularly imprinted polymers (MIPs) were developed to specifically capture prototypical quorum sensing autoinducers [i.e., N-(3-oxododecanoyl)-L-homoserine lactone (3-oxo-C12AHL)], interrupt quorum sensing, and subsequently inhibit biofilm formation of Pseudomonas aeruginosa, an important human nosocomial pathogen. The synthesis of MIPs was optimized by considering the amount and type of the functional monomers itaconic acid (IA) and 2-hydroxyethyl methacrylate (HEMA). IA-based MIPs showed high adsorption affinity towards 3-oxo-C12AHL with an imprinting factor of 1.68. Compared to IA-based MIPs, the adsorption capacity of HEMA-based MIPs was improved 5-fold. HEMA-based MIPs significantly reduced biofilm formation (by ~65%), while biofilm suppression by IA-based MIPs was neutralized due to increased bacterial attachment. The developed MIPs represent promising alternative biofilm intervention agents that can be applied to surfaces relevant to clinical settings and food processing equipment.

  17. Inhibition of Streptococcus mutans biofilm formation, extracellular polysaccharide production, and virulence by an oxazole derivative.

    Science.gov (United States)

    Chen, Lulu; Ren, Zhi; Zhou, Xuedong; Zeng, Jumei; Zou, Jing; Li, Yuqing

    2016-01-01

    Dental caries, a biofilm-related oral disease, is a result of disruption of the microbial ecological balance in the oral environment. Streptococcus mutans, which is one of the primary cariogenic bacteria, produces glucosyltransferases (Gtfs) that synthesize extracellular polysaccharides (EPSs). The EPSs, especially water-insoluble glucans, contribute to the formation of dental plaque, biofilm stability, and structural integrity, by allowing bacteria to adhere to tooth surfaces and supplying the bacteria with protection against noxious stimuli and other environmental attacks. The identification of novel alternatives that selectively inhibit cariogenic organisms without suppressing oral microbial residents is required. The goal of the current study is to investigate the influence of an oxazole derivative on S. mutans biofilm formation and the development of dental caries in rats, given that oxazole and its derivatives often exhibit extensive and pharmacologically important biological activities. Our data shows that one particular oxazole derivative, named 5H6, inhibited the formation of S. mutans biofilms and prevented synthesis of extracellular polysaccharides by antagonizing Gtfs in vitro, without affecting the growth of the bacteria. In addition, topical applications with the inhibitor resulted in diminished incidence and severity of both smooth and sulcal surface caries in vivo with a lower percentage of S. mutans in the animals' dental plaque compared to the control group (P mutans.

  18. Inhibition of Streptococcus mutans biofilm formation on composite resins containing ursolic acid

    Science.gov (United States)

    Kim, Soohyeon; Song, Minju; Roh, Byoung-Duck; Park, Sung-Ho

    2013-01-01

    Objectives To evaluate the inhibitory effect of ursolic acid (UA)-containing composites on Streptococcus mutans (S. mutans) biofilm. Materials and Methods Composite resins with five different concentrations (0.04, 0.1, 0.2, 0.5, and 1.0 wt%) of UA (U6753, Sigma Aldrich) were prepared, and their flexural strengths were measured according to ISO 4049. To evaluate the effect of carbohydrate source on biofilm formation, either glucose or sucrose was used as a nutrient source, and to investigate the effect of saliva treatment, the specimen were treated with either unstimulated whole saliva or phosphate-buffered saline (PBS). For biofilm assay, composite disks were transferred to S. mutans suspension and incubated for 24 hr. Afterwards, the specimens were rinsed with PBS and sonicated. The colony forming units (CFU) of the disrupted biofilm cultures were enumerated. For growth inhibition test, the composites were placed on a polystyrene well cluster, and S. mutans suspension was inoculated. The optical density at 600 nm (OD600) was recorded by Infinite F200 pro apparatus (TECAN). One-way ANOVA and two-way ANOVA followed by Bonferroni correction were used for the data analyses. Results The flexural strength values did not show significant difference at any concentration (p > 0.01). In biofilm assay, the CFU score decreased as the concentration of UA increased. The influence of saliva pretreatment was conflicting. The sucrose groups exhibited higher CFU score than glucose group (p composite showed inhibitory effect on S. mutans biofilm formation and growth. PMID:23741708

  19. Limonene inhibits streptococcal biofilm formation by targeting surface-associated virulence factors.

    Science.gov (United States)

    Subramenium, Ganapathy Ashwinkumar; Vijayakumar, Karuppiah; Pandian, Shunmugiah Karutha

    2015-08-01

    The present study explores the efficacy of limonene, a cyclic terpene found in the rind of citrus fruits, for antibiofilm potential against species of the genus Streptococcus, which have been deeply studied worldwide owing to their multiple pathogenic efficacy. Limonene showed a concentration-dependent reduction in the biofilm formation of Streptococcus pyogenes (SF370), with minimal biofilm inhibitory concentration (MBIC) of 400 μg ml - 1. Limonene was found to possess about 75-95 % antibiofilm activity against all the pathogens tested, viz. Streptococcus pyogenes (SF370 and 5 clinical isolates), Streptococcus mutans (UA159) and Streptococcus mitis (ATCC 6249) at 400 μg ml - 1 concentration. Microscopic analysis of biofilm architecture revealed a quantitative breach in biofilm formation. Results of a surface-coating assay suggested that the possible mode of action of limonene could be by inhibiting bacterial adhesion to surfaces, thereby preventing the biofilm formation cascade. Susceptibility of limonene-treated Streptococcus pyogenes to healthy human blood goes in unison with gene expression studies in which the mga gene was found to be downregulated. Anti-cariogenic efficacy of limonene against Streptococcus mutans was confirmed, with inhibition of acid production and downregulation of the vicR gene. Downregulation of the covR, mga and vicR genes, which play a critical role in regulating surface-associated proteins in Streptococcus pyogenes and Streptococcus mutans, respectively, is yet further evidence to show that limonene targets surface-associated proteins. The results of physiological assays and gene expression studies clearly show that the surface-associated antagonistic mechanism of limonene also reduces surface-mediated virulence factors.

  20. Probiotic Lactobacillus sp. inhibit growth, biofilm formation and gene expression of caries-inducing Streptococcus mutans.

    Science.gov (United States)

    Wasfi, Reham; Abd El-Rahman, Ola A; Zafer, Mai M; Ashour, Hossam M

    2018-03-01

    Streptococcus mutans contributes significantly to dental caries, which arises from homoeostasic imbalance between host and microbiota. We hypothesized that Lactobacillus sp. inhibits growth, biofilm formation and gene expression of Streptococcus mutans. Antibacterial (agar diffusion method) and antibiofilm (crystal violet assay) characteristics of probiotic Lactobacillus sp. against Streptococcus mutans (ATCC 25175) were evaluated. We investigated whether Lactobacillus casei (ATCC 393), Lactobacillus reuteri (ATCC 23272), Lactobacillus plantarum (ATCC 14917) or Lactobacillus salivarius (ATCC 11741) inhibit expression of Streptococcus mutans genes involved in biofilm formation, quorum sensing or stress survival using quantitative real-time polymerase chain reaction (qPCR). Growth changes (OD600) in the presence of pH-neutralized, catalase-treated or trypsin-treated Lactobacillus sp. supernatants were assessed to identify roles of organic acids, peroxides and bacteriocin. Susceptibility testing indicated antibacterial (pH-dependent) and antibiofilm activities of Lactobacillus sp. against Streptococcus mutans. Scanning electron microscopy revealed reduction in microcolony formation and exopolysaccharide structural changes. Of the oral normal flora, L. salivarius exhibited the highest antibiofilm and peroxide-dependent antimicrobial activities. All biofilm-forming cells treated with Lactobacillus sp. supernatants showed reduced expression of genes involved in exopolysaccharide production, acid tolerance and quorum sensing. Thus, Lactobacillus sp. can inhibit tooth decay by limiting growth and virulence properties of Streptococcus mutans. © 2018 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  1. Anti-Biofilm and Immunomodulatory Activities of Peptides That Inhibit Biofilms Formed by Pathogens Isolated from Cystic Fibrosis Patients

    Directory of Open Access Journals (Sweden)

    César de la Fuente-Núñez

    2014-10-01

    Full Text Available Cystic fibrosis (CF patients often acquire chronic respiratory tract infections due to Pseudomonas aeruginosa and Burkholderia cepacia complex (Bcc species. In the CF lung, these bacteria grow as multicellular aggregates termed biofilms. Biofilms demonstrate increased (adaptive resistance to conventional antibiotics, and there are currently no available biofilm-specific therapies. Using plastic adherent, hydroxyapatite and flow cell biofilm models coupled with confocal and scanning electron microscopy, it was demonstrated that an anti-biofilm peptide 1018 prevented biofilm formation, eradicated mature biofilms and killed biofilms formed by a wide range of P. aeruginosa and B. cenocepacia clinical isolates. New peptide derivatives were designed that, compared to their parent peptide 1018, showed similar or decreased anti-biofilm activity against P. aeruginosa biofilms, but increased activity against biofilms formed by the Gram-positive bacterium methicillin resistant Staphylococcus aureus. In addition, some of these new peptide derivatives retained the immunomodulatory activity of 1018 since they induced the production of the chemokine monocyte chemotactic protein-1 (MCP-1 and suppressed lipopolysaccharide-mediated tumor necrosis factor-α (TNF-α production by human peripheral blood mononuclear cells (PBMC and were non-toxic towards these cells. Peptide 1018 and its derivatives provide promising leads for the treatment of chronic biofilm infections and hyperinflammatory lung disease in CF patients.

  2. Transcriptional and functional analysis of the effects of magnolol: inhibition of autolysis and biofilms in Staphylococcus aureus.

    Science.gov (United States)

    Wang, Dacheng; Jin, Qi; Xiang, Hua; Wang, Wei; Guo, Na; Zhang, Kaiyu; Tang, Xudong; Meng, Rizeng; Feng, Haihua; Liu, Lihui; Wang, Xiaohong; Liang, Junchao; Shen, Fengge; Xing, Mingxun; Deng, Xuming; Yu, Lu

    2011-01-01

    The targeting of Staphylococcus aureus biofilm structures are now gaining interest as an alternative strategy for developing new types of antimicrobial agents. Magnolol (MOL) shows inhibitory activity against S. aureus biofilms and Triton X-100-induced autolysis in vitro, although there are no data regarding the molecular mechanisms of MOL action in bacteria. The molecular basis of the markedly reduced autolytic phenotype and biofilm inhibition triggered by MOL were explored using transcriptomic analysis, and the transcription of important genes were verified by real-time RT-PCR. The inhibition of autolysis by MOL was evaluated using quantitative bacteriolytic assays and zymographic analysis, and antibiofilm activity assays and confocal laser scanning microscopy were used to elucidate the inhibition of biofilm formation caused by MOL in 20 clinical isolates or standard strains. The reduction in cidA, atl, sle1, and lytN transcript levels following MOL treatment was consistent with the induced expression of their autolytic repressors lrgA, lrgB, arlR, and sarA. MOL generally inhibited or reversed the expression of most of the genes involved in biofilm production. The growth of S. aureus strain ATCC 25923 in the presence of MOL dose-dependently led to decreases in Triton X-100-induced autolysis, extracellular murein hydrolase activity, and the amount of extracellular DNA (eDNA). MOL may impede biofilm formation by reducing the expression of cidA, a murein hydrolase regulator, to inhibit autolysis and eDNA release, or MOL may directly repress biofilm formation. MOL shows in vitro antimicrobial activity against clinical and standard S. aureus strains grown in planktonic and biofilm cultures, suggesting that the structure of MOL may potentially be used as a basis for the development of drugs targeting biofilms.

  3. Transcriptional and functional analysis of the effects of magnolol: inhibition of autolysis and biofilms in Staphylococcus aureus.

    Directory of Open Access Journals (Sweden)

    Dacheng Wang

    Full Text Available BACKGROUND: The targeting of Staphylococcus aureus biofilm structures are now gaining interest as an alternative strategy for developing new types of antimicrobial agents. Magnolol (MOL shows inhibitory activity against S. aureus biofilms and Triton X-100-induced autolysis in vitro, although there are no data regarding the molecular mechanisms of MOL action in bacteria. METHODOLOGY/PRINCIPAL FINDINGS: The molecular basis of the markedly reduced autolytic phenotype and biofilm inhibition triggered by MOL were explored using transcriptomic analysis, and the transcription of important genes were verified by real-time RT-PCR. The inhibition of autolysis by MOL was evaluated using quantitative bacteriolytic assays and zymographic analysis, and antibiofilm activity assays and confocal laser scanning microscopy were used to elucidate the inhibition of biofilm formation caused by MOL in 20 clinical isolates or standard strains. The reduction in cidA, atl, sle1, and lytN transcript levels following MOL treatment was consistent with the induced expression of their autolytic repressors lrgA, lrgB, arlR, and sarA. MOL generally inhibited or reversed the expression of most of the genes involved in biofilm production. The growth of S. aureus strain ATCC 25923 in the presence of MOL dose-dependently led to decreases in Triton X-100-induced autolysis, extracellular murein hydrolase activity, and the amount of extracellular DNA (eDNA. MOL may impede biofilm formation by reducing the expression of cidA, a murein hydrolase regulator, to inhibit autolysis and eDNA release, or MOL may directly repress biofilm formation. CONCLUSIONS/SIGNIFICANCE: MOL shows in vitro antimicrobial activity against clinical and standard S. aureus strains grown in planktonic and biofilm cultures, suggesting that the structure of MOL may potentially be used as a basis for the development of drugs targeting biofilms.

  4. Inhibition of biofilm formation by D-tyrosine: Effect of bacterial type and D-tyrosine concentration.

    Science.gov (United States)

    Yu, Cong; Li, Xuening; Zhang, Nan; Wen, Donghui; Liu, Charles; Li, Qilin

    2016-04-01

    D-Tyrosine inhibits formation and triggers disassembly of bacterial biofilm and has been proposed for biofouling control applications. This study probes the impact of D-tyrosine in different biofilm formation stages in both G+ and G- bacteria, and reveals a non-monotonic correlation between D-tyrosine concentration and biofilm inhibition effect. In the attachment stage, cell adhesion was studied in a flow chamber, where D-tyrosine caused significant reduction in cell attachment. Biofilms formed by Pseudomonas aeruginosa and Bacillus subtilis were characterized by confocal laser scanning microscopy as well as quantitative analysis of cellular biomass and extracellular polymeric substances. D-Tyrosine exhibited strong inhibitive effects on both biofilms with an effective concentration as low as 5 nM; the biofilms responded to D-tyrosine concentration change in a non-monotonic, bi-modal pattern. In addition, D-tyrosine showed notable and different impact on EPS production by G+ and G- bacteria. Extracellular protein was decreased in P. aeruginosa biofilms, but increased in those of B. subtilis. Exopolysaccharides production by P. aeruginosa was increased at low concentrations and reduced at high concentrations while no impact was found in B. subtilis. These results suggest that distinct mechanisms are at play at different D-tyrosine concentrations and they may be species specific. Dosage of D-tyrosine must be carefully controlled for biofouling control applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Extract from the fermented soybean product Natto inhibits Vibrio biofilm formation and reduces shrimp mortality from Vibrio harveyi infection.

    Science.gov (United States)

    Yatip, Pattanan; Nitin Chandra Teja, D; Flegel, Timothy W; Soowannayan, Chumporn

    2018-01-01

    Many bacteria, including Vibrio pathogens of shrimp, need to colonize and/or form biofilms in hosts or the environment to cause disease. Thus, one possible control strategy for shrimp Vibriosis is biofilm inhibition. With this objective, an extract from the Japanese fermented soybean product, Natto was tested with the luminescent shrimp pathogen Vibrio harveyi (VH) for its ability to inhibit or degrade biofilm and to interfere with cell growth in broth. Natto is a traditional fermentation product of Bacillus subtilis var Natto (BSN1). Using 96 well microtiter plates coated with 0.4% chitosan, we found that biofilm formation by VH was inhibited, while growth in parallel broth cultures was not. When an extract from Natto prepared using BSN1 was mixed with feed for the whiteleg shrimp Penaeus vannamei before immersion challenge with V. harveyi at 10 6  cfu/ml, survival was significantly higher (p≤0.05) than for control shrimp given feed without these additives. Further work done to test whether d-amino acids were involved in biofilm formation as previously reported for B. subtilis, Staphylococus aureus and Pseudomonas aeruginosa gave negative results. In conclusion, we discovered that Natto extract can inhibit Vibrio biofilm formation and that it or BSN1 alone added to shrimp feed can significantly reduce shrimp mortality in immersion challenges with pathogenic VH. This shows some promise for possible application against Vibriosis in shrimp since Natto is generally regarded as safe (GRAS) for human consumption. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Essential Oils and Eugenols Inhibit Biofilm Formation and the Virulence of Escherichia coli O157:H7

    Science.gov (United States)

    Kim, Yong-Guy; Lee, Jin-Hyung; Gwon, Giyeon; Kim, Soon-Il; Park, Jae Gyu; Lee, Jintae

    2016-01-01

    Enterohemorrhagic Escherichia coli O157:H7 (EHEC) has caused foodborne outbreaks worldwide and the bacterium forms antimicrobial-tolerant biofilms. We investigated the abilities of various plant essential oils and their components to inhibit biofilm formation by EHEC. Bay, clove, pimento berry oils and their major common constituent eugenol at 0.005% (v/v) were found to markedly inhibit EHEC biofilm formation without affecting planktonic cell growth. In addition, three other eugenol derivatives isoeugenol, 2-methoxy-4-propylphenol, and 4-ethylguaiacol had antibiofilm activity, indicating that the C-1 hydroxyl unit, the C-2 methoxy unit, and C-4 alkyl or alkane chain on the benzene ring of eugenol play important roles in antibiofilm activity. Interestingly, these essential oils and eugenol did not inhibit biofilm formation by three laboratory E. coli K-12 strains that reduced curli fimbriae production. Transcriptional analysis showed that eugenol down-regulated 17 of 28 genes analysed, including curli genes (csgABDFG), type I fimbriae genes (fimCDH) and ler-controlled toxin genes (espD, escJ, escR, and tir), which are required for biofilm formation and the attachment and effacement phenotype. In addition, biocompatible poly(lactic-co-glycolic acid) coatings containing clove oil or eugenol exhibited efficient biofilm inhibition on solid surfaces. In a Caenorhabditis elegans nematode model, clove oil and eugenol attenuated the virulence of EHEC. PMID:27808174

  7. Commensal coagulase-negative Staphylococcus from the udder of healthy cows inhibits biofilm formation of mastitis-related pathogens.

    Science.gov (United States)

    Isaac, Paula; Bohl, Luciana Paola; Breser, María Laura; Orellano, María Soledad; Conesa, Agustín; Ferrero, Marcela Alejandra; Porporatto, Carina

    2017-08-01

    Bovine mastitis, considered the most important cause of economic losses in the dairy industry, is a major concern in veterinary medicine. Staphylococcus aureus and coagulase-negative staphylococci (CNS) are the main pathogens associated with intramammary infections, and bacterial biofilms are suspected to be responsible for the persistence of this disease. CNS from the udder are not necessarily associated with intramammary infections. In fact, some commensal CNS have been shown to have biological activities. This issue led us to screen exoproducts from commensal Staphylococcus chromogenes for anti-biofilm activity against different mastitis pathogens. The cell-free supernatant from S. chromogenes LN1 (LN1-CFS) was confirmed to display a non-biocidal inhibition of pathogenic biofilms. The supernatant was subjected to various treatments to estimate the nature of the biofilm-inhibiting compounds. The results showed that the bioactive compound >5KDa in mass is sensitive to thermal treatment and proteinase K digestion, suggesting its protein properties. LN1-CFS was able to significantly inhibit S. aureus and CNS biofilm formation in a dose-independent manner and without affecting the viability of bovine cells. These findings reveal a new activity of the udder microflora of healthy animals. Studies are underway to purify and identify the anti-biofilm biocompound and to evaluate its biological activity in vivo. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Calcium-chelating alizarin and other anthraquinones inhibit biofilm formation and the hemolytic activity of Staphylococcus aureus.

    Science.gov (United States)

    Lee, Jin-Hyung; Kim, Yong-Guy; Yong Ryu, Shi; Lee, Jintae

    2016-01-14

    Staphylococcal biofilms are problematic and play a critical role in the persistence of chronic infections because of their abilities to tolerate antimicrobial agents. Thus, the inhibitions of biofilm formation and/or toxin production are viewed as alternative means of controlling Staphylococcus aureus infections. Here, the antibiofilm activities of 560 purified phytochemicals were examined. Alizarin at 10 μg/ml was found to efficiently inhibit biofilm formation by three S. aureus strains and a Staphylococcus epidermidis strain. In addition, two other anthraquinones purpurin and quinalizarin were found to have antibiofilm activity. Binding of Ca(2+) by alizarin decreased S. aureus biofilm formation and a calcium-specific chelating agent suppressed the effect of calcium. These three anthraquinones also markedly inhibited the hemolytic activity of S. aureus, and in-line with their antibiofilm activities, increased cell aggregation. A chemical structure-activity relationship study revealed that two hydroxyl units at the C-1 and C-2 positions of anthraquinone play important roles in antibiofilm and anti-hemolytic activities. Transcriptional analyses showed that alizarin repressed the α-hemolysin hla gene, biofilm-related genes (psmα, rbf, and spa), and modulated the expressions of cid/lrg genes (the holin/antiholin system). These findings suggest anthraquinones, especially alizarin, are potentially useful for controlling biofilm formation and the virulence of S. aureus.

  9. Capric acid secreted by S. boulardii inhibits C. albicans filamentous growth, adhesion and biofilm formation.

    Directory of Open Access Journals (Sweden)

    Anna Murzyn

    Full Text Available Candidiasis are life-threatening systemic fungal diseases, especially of gastro intestinal track, skin and mucous membranes lining various body cavities like the nostrils, the mouth, the lips, the eyelids, the ears or the genital area. Due to increasing resistance of candidiasis to existing drugs, it is very important to look for new strategies helping the treatment of such fungal diseases. One promising strategy is the use of the probiotic microorganisms, which when administered in adequate amounts confer a health benefit. Such a probiotic microorganism is yeast Saccharomyces boulardii, a close relative of baker yeast. Saccharomyces boulardii cells and their extract affect the virulence factors of the important human fungal pathogen C. albicans, its hyphae formation, adhesion and biofilm development. Extract prepared from S. boulardii culture filtrate was fractionated and GC-MS analysis showed that the active fraction contained, apart from 2-phenylethanol, caproic, caprylic and capric acid whose presence was confirmed by ESI-MS analysis. Biological activity was tested on C. albicans using extract and pure identified compounds. Our study demonstrated that this probiotic yeast secretes into the medium active compounds reducing candidal virulence factors. The chief compound inhibiting filamentous C. albicans growth comparably to S. boulardii extract was capric acid, which is thus responsible for inhibition of hyphae formation. It also reduced candidal adhesion and biofilm formation, though three times less than the extract, which thus contains other factors suppressing C. albicans adherence. The expression profile of selected genes associated with C. albicans virulence by real-time PCR showed a reduced expression of HWP1, INO1 and CSH1 genes in C. albicans cells treated with capric acid and S. boulardii extract. Hence capric acid secreted by S. boulardii is responsible for inhibition of C. albicans filamentation and partially also adhesion and

  10. Capric Acid Secreted by S. boulardii Inhibits C. albicans Filamentous Growth, Adhesion and Biofilm Formation

    Science.gov (United States)

    Murzyn, Anna; Krasowska, Anna; Stefanowicz, Piotr; Dziadkowiec, Dorota; Łukaszewicz, Marcin

    2010-01-01

    Candidiasis are life-threatening systemic fungal diseases, especially of gastro intestinal track, skin and mucous membranes lining various body cavities like the nostrils, the mouth, the lips, the eyelids, the ears or the genital area. Due to increasing resistance of candidiasis to existing drugs, it is very important to look for new strategies helping the treatment of such fungal diseases. One promising strategy is the use of the probiotic microorganisms, which when administered in adequate amounts confer a health benefit. Such a probiotic microorganism is yeast Saccharomyces boulardii, a close relative of baker yeast. Saccharomyces boulardii cells and their extract affect the virulence factors of the important human fungal pathogen C. albicans, its hyphae formation, adhesion and biofilm development. Extract prepared from S. boulardii culture filtrate was fractionated and GC-MS analysis showed that the active fraction contained, apart from 2-phenylethanol, caproic, caprylic and capric acid whose presence was confirmed by ESI-MS analysis. Biological activity was tested on C. albicans using extract and pure identified compounds. Our study demonstrated that this probiotic yeast secretes into the medium active compounds reducing candidal virulence factors. The chief compound inhibiting filamentous C. albicans growth comparably to S. boulardii extract was capric acid, which is thus responsible for inhibition of hyphae formation. It also reduced candidal adhesion and biofilm formation, though three times less than the extract, which thus contains other factors suppressing C. albicans adherence. The expression profile of selected genes associated with C. albicans virulence by real-time PCR showed a reduced expression of HWP1, INO1 and CSH1 genes in C. albicans cells treated with capric acid and S. boulardii extract. Hence capric acid secreted by S. boulardii is responsible for inhibition of C. albicans filamentation and partially also adhesion and biofilm formation. PMID

  11. Inhibition of Escherichia coli O157:H7 on stainless steel using Pseudomonas veronii biofilms.

    Science.gov (United States)

    Kim, Y; Kim, H; Beuchat, L R; Ryu, J-H

    2018-05-01

    We produced a Pseudomonas veronii biofilm on the surface of a stainless steel that is inhibitory to Escherichia coli O157:H7. Pseudomonas veronii strain KACC 81051BP, isolated from lettuce, readily formed biofilm on the surface of stainless steel coupons (SSCs) immersed in tryptic soy broth at 25°C. Cells showed significantly (P ≤ 0·05) enhanced tolerance to desiccation stress (43% relative humidity (RH)) and retained antimicrobial activity against E. coli O157:H7. The number of E. coli O157:H7 (control; 4·1 ± 0·1 log CFU per coupon) on sterile SSCs decreased to 2·7 ± 0·2 log CFU per coupon after exposure to 43% RH at 25°C for 48 h, while the population of E. coli O157:H7 (4·1 ± 0·0 log CFU per coupon) on SSCs containing P. veronii biofilm decreased to below the theoretical detection limit (1·5 log CFU per coupon) within 24 h. The antimicrobial biofilm produced on stainless steel may have application in preventing cross-contamination by E. coli O157:H7 on other abiotic surfaces in food-contact environments. The presence of Escherichia coli O157:H7 on environmental surfaces of food manufacturing, transportation and storage facilities is a significant food safety concern because it can result in cross-contamination of food products. In this study, we developed a Pseudomonas veronii biofilm on the surface of a stainless steel that inhibits the growth of E. coli O157:H7. Since P. veronii in biofilm resists desiccation, it provides persistent antimicrobial activity. Information presented here provides novel and practical insights to developing biological strategies to inactivate E. coli O157:H7 on diverse surfaces in food processing and handling environments. © 2018 The Society for Applied Microbiology.

  12. Inhibition of biofilm formation, quorum sensing and infection in Pseudomonas aeruginosa by natural products-inspired organosulfur compounds.

    Directory of Open Access Journals (Sweden)

    Nathaniel C Cady

    Full Text Available Using a microplate-based screening assay, the effects on Pseudomonas aeruginosa PAO1 biofilm formation of several S-substituted cysteine sulfoxides and their corresponding disulfide derivatives were evaluated. From our library of compounds, S-phenyl-L-cysteine sulfoxide and its breakdown product, diphenyl disulfide, significantly reduced the amount of biofilm formation by P. aeruginosa at levels equivalent to the active concentration of 4-nitropyridine-N-oxide (NPO (1 mM. Unlike NPO, which is an established inhibitor of bacterial biofilms, our active compounds did not reduce planktonic cell growth and only affected biofilm formation. When used in a Drosophila-based infection model, both S-phenyl-L-cysteine sulfoxide and diphenyl disulfide significantly reduced the P. aeruginosa recovered 18 h post infection (relative to the control, and were non-lethal to the fly hosts. The possibility that the observed biofilm inhibitory effects were related to quorum sensing inhibition (QSI was investigated using Escherichia coli-based reporters expressing P. aeruginosa lasR or rhIR response proteins, as well as an endogenous P. aeruginosa reporter from the lasI/lasR QS system. Inhibition of quorum sensing by S-phenyl-L-cysteine sulfoxide was observed in all of the reporter systems tested, whereas diphenyl disulfide did not exhibit QSI in either of the E. coli reporters, and showed very limited inhibition in the P. aeruginosa reporter. Since both compounds inhibit biofilm formation but do not show similar QSI activity, it is concluded that they may be functioning by different pathways. The hypothesis that biofilm inhibition by the two active compounds discovered in this work occurs through QSI is discussed.

  13. Culture Supernatants of Lactobacillus gasseri and L. crispatus Inhibit Candida albicans Biofilm Formation and Adhesion to HeLa Cells.

    Science.gov (United States)

    Matsuda, Yuko; Cho, Otomi; Sugita, Takashi; Ogishima, Daiki; Takeda, Satoru

    2018-03-30

    Vulvovaginal candidiasis (VVC) is a common superficial infection of the vaginal mucous membranes caused by the fungus Candida albicans. The aim of this study was to assess the mechanisms underlying the inhibitory effects of the culture supernatants of Lactobacillus gasseri and L. crispatus, the predominant microbiota in Asian healthy women, on C. albicans biofilm formation. The inhibition of C. albicans adhesion to HeLa cells by Lactobacillus culture supernatant was also investigated. Candida albicans biofilm was formed on polystyrene flat-bottomed 96-well plates, and the inhibitory effects on the initial colonization and maturation phases were determined using the XTT reduction assay. The expression levels of biofilm formation-associated genes (HWP1, ECE1, ALS3, BCR1, EFG1, TEC1, and CPH1) were determined by reverse transcription quantitative polymerase chain reaction. The inhibition of C. albicans adhesion to HeLa cells by Lactobacillus culture supernatant was evaluated by enumerating viable C. albicans cells. The culture supernatants of both Lactobacillus species inhibited the initial colonization and maturation of C. albicans biofilm. The expression levels of all biofilm formation-related genes were downregulated in the presence of Lactobacillus culture supernatant. The culture supernatant also inhibited C. albicans adhesion to HeLa cells. The culture supernatants of L. gasseri and L. crispatus inhibited C. albicans biofilm formation by downregulating biofilm formation-related genes and C. albicans adhesion to HeLa cells. These findings support the notion that Lactobacillus metabolites may be useful alternatives to antifungal drugs for the management of VVC.

  14. Aerobic Biofilms Grown from Athabasca Watershed Sediments Are Inhibited by Increasing Concentrations of Bituminous Compounds

    Science.gov (United States)

    Lawrence, John R.; Sanschagrin, Sylvie; Roy, Julie L.; Swerhone, George D. W.; Korber, Darren R.; Greer, Charles W.

    2013-01-01

    Sediments from the Athabasca River and its tributaries naturally contain bitumen at various concentrations, but the impacts of this variation on the ecology of the river are unknown. Here, we used controlled rotating biofilm reactors in which we recirculated diluted sediments containing various concentrations of bituminous compounds taken from the Athabasca River and three tributaries. Biofilms exposed to sediments having low and high concentrations of bituminous compounds were compared. The latter were 29% thinner, had a different extracellular polysaccharide composition, 67% less bacterial biomass per μm2, 68% less cyanobacterial biomass per μm2, 64% less algal biomass per μm2, 13% fewer protozoa per cm2, were 21% less productive, and had a 33% reduced content in chlorophyll a per mm2 and a 20% reduction in the expression of photosynthetic genes, but they had a 23% increase in the expression of aromatic hydrocarbon degradation genes. Within the Bacteria, differences in community composition were also observed, with relatively more Alphaproteobacteria and Betaproteobacteria and less Cyanobacteria, Bacteroidetes, and Firmicutes in biofilms exposed to high concentrations of bituminous compounds. Altogether, our results suggest that biofilms that develop in the presence of higher concentrations of bituminous compounds are less productive and have lower biomass, linked to a decrease in the activities and abundance of photosynthetic organisms likely due to inhibitory effects. However, within this general inhibition, some specific microbial taxa and functional genes are stimulated because they are less sensitive to the inhibitory effects of bituminous compounds or can degrade and utilize some bitumen-associated compounds. PMID:24056457

  15. Inhibition of Candida albicans Biofilm Formation by the Synthetic Lactoferricin Derived Peptide hLF1-11.

    Science.gov (United States)

    Morici, Paola; Fais, Roberta; Rizzato, Cosmeri; Tavanti, Arianna; Lupetti, Antonella

    2016-01-01

    The aim of this study was to evaluate the in vitro activity of the synthetic peptide hLF1-11 against biofilm produced by clinical isolates of Candida albicans with different fluconazole susceptibility. The antibiofilm activity of the peptide hLF1-11 was assessed in terms of reduction of biofilm cellular density, metabolic activity and sessile cell viability. The extent of morphogenesis in hLF1-11 treated and untreated biofilms was also investigated microscopically. Transcription levels of genes related to cell adhesion, hyphal development and extracellular matrix production were analysed by qRT-PCR in hLF1-11 treated and untreated biofilms. Exogenous dibutyryl-cAMP (db-cAMP) was used to rescue morphogenesis in cells exposed to the peptide. The results revealed that hLF1-11 exhibited an inhibitory effect on biofilm formation by all C. albicans isolates tested in a dose-dependent manner, regardless of their fluconazole susceptibility. Visual inspection of treated or untreated biofilm cells with an inverted microscope revealed a significant reduction in hyphal formation by hLF1-11 treated cells, as early as 3 hours of incubation. Moreover, hLF1-11 showed a reduced activity on preadherent cells. hLF1-11 induced the down-regulation of biofilm and hyphal-associated genes, which were predominantly regulated via the Ras1-cAMP-Efg1 pathway. Indeed, exogenous db-cAMP restored morphogenesis in hLF1-11 treated cells. The hLF1-11 peptide significantly inhibited biofilm formation by C. albicans mainly at early stages, interfering with biofilm cellular density and metabolic activity, and affected morphogenesis through the Ras1-cAMP-Efg1 pathway. Our findings provide the first evidence that hLF1-11 could represent a potential candidate for the prevention of biofilm formation by C. albicans.

  16. Inhibited Bacterial Adhesion and Biofilm Formation on Quaternized Chitosan-Loaded Titania Nanotubes with Various Diameters

    Directory of Open Access Journals (Sweden)

    Wen-tao Lin

    2016-03-01

    Full Text Available Titania nanotube-based local drug delivery is an attractive strategy for combating implant-associated infection. In our previous study, we demonstrated that the gentamicin-loaded nanotubes could dramatically inhibit bacterial adhesion and biofilm formation on implant surfaces. Considering the overuse of antibiotics may lead to the evolution of antibiotic-resistant bacteria, we synthesized a new quaternized chitosan derivative (hydroxypropyltrimethyl ammonium chloride chitosan, HACC with a 27% degree of substitution (DS; referred to as 27% HACC that had a strong antibacterial activity and simultaneously good biocompatibility with osteogenic cells. Titania nanotubes with various diameters (80, 120, 160, and 200 nm and 200 nm length were loaded with 2 mg of HACC using a lyophilization method and vacuum drying. Two standard strain, methicillin-resistant Staphylococcus aureus (American Type Culture Collection 43300 and Staphylococcus epidermidis (American Type Culture Collection 35984, and two clinical isolates, S. aureus 376 and S. epidermidis 389, were selected to investigate the bacterial adhesion at 6 h and biofilm formation at 24, 48, and 72 h on the HACC-loaded nanotubes (NT-H using the spread plate method, confocal laser scanning microscopy (CLSM, and scanning electron microscopy (SEM. Smooth titanium (Smooth Ti was also investigated and compared. We found that NT-H could significantly inhibit bacterial adhesion and biofilm formation on its surface compared with Smooth Ti, and the NT-H with 160 nm and 200 nm diameters had stronger antibacterial activity because of the extended HACC release time of NT-H with larger diameters. Therefore, NT-H can significantly improve the antibacterial ability of orthopedic implants and provide a promising strategy to prevent implant-associated infections.

  17. Allicin from garlic inhibits the biofilm formation and urease activity of Proteus mirabilis in vitro.

    Science.gov (United States)

    Ranjbar-Omid, Mahsa; Arzanlou, Mohsen; Amani, Mojtaba; Shokri Al-Hashem, Seyyedeh Khadijeh; Amir Mozafari, Nour; Peeri Doghaheh, Hadi

    2015-05-01

    Several virulence factors contribute to the pathogenesis of Proteus mirabilis. This study determined the inhibitory effects of allicin on urease, hemolysin and biofilm of P. mirabilis ATCC 12453 and its antimicrobial activity against 20 clinical isolates of P. mirabilis. Allicin did not inhibit hemolysin, whereas it did inhibit relative urease activity in both pre-lysed (half-maximum inhibitory concentration, IC50 = 4.15 μg) and intact cells (IC50 = 21 μg) in a concentration-dependent manner. Allicin at sub-minimum inhibitory concentrations (2-32 μg mL(-1)) showed no significant effects on the growth of the bacteria (P > 0.05), but it reduced biofilm development in a concentration-dependent manner (P mirabilis isolates were determined to be 128 and 512 μg mL(-1), respectively. The results suggest that allicin could have clinical applications in controlling P. mirabilis infections. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. Penicillenols from a deep-sea fungus Aspergillus restrictus inhibit Candida albicans biofilm formation and hyphal growth.

    Science.gov (United States)

    Wang, Jie; Yao, Qi-Feng; Amin, Muhammad; Nong, Xu-Hua; Zhang, Xiao-Yong; Qi, Shu-Hua

    2017-06-01

    Penicillenols (A1, A2, B1, B2, C1 and C2) were isolated from Aspergillus restrictus DFFSCS006, and could differentially inhibit biofilm formation and eradicate pre-developed biofilms of Candida albicans. Their structure-bioactivity relationships suggested that the saturation of hydrocarbon chain at C-8, R-configuration of C-5 and trans-configuration of the double bond between C-5 and C-6 of pyrrolidine-2,4-dione unit were important for their anti-biofilm activities. Penicillenols A2 and B1 slowed the hyphal growth and suppressed the transcripts of hypha specific genes HWP1, ALS1, ALS3, ECE1 and SAP4. Moreover, penicillenols A2 and B1 were found to act synergistically with amphotericin B against C. albicans biofilm formation.

  19. Inhibition and recovery of nitrification in treating real coal gasification wastewater with moving bed biofilm reactor

    Institute of Scientific and Technical Information of China (English)

    Huiqiang Li; Hongjun Han; Maoan Du; Wei Wang

    2011-01-01

    Moving bed biofilm reactor (MBBR) was used to treat real coal gasification wastewater.Nitrification of the MBBR was inhibited almost completely during start-up period.Sudden increase of influent total NH3 concentration was the main factor inducing nitrification inhibition.Increasing DO concentration in the bulk liquid (from 2 to 3 mg/L) had little effect on nitrification recovery.Nitrification of the MBBR recovered partially by the addition of nitrifying sludge into the reactor and almost ceased within 5 days.Nitrification ratio of the MBBR achieved 65% within 12 days by increasing dilute ratio of the influent wastewater with tap water.The ratio of nitrification decreased to 25% when infiuent COD concentration increased from 650 to 1000 mg/L after nitrification recovery and recovered 70%for another 4 days.

  20. Hygrocin C from marine-derived Streptomyces sp. SCSGAA 0027 inhibits biofilm formation in Bacillus amyloliquefaciens SCSGAB0082 isolated from South China Sea gorgonian.

    Science.gov (United States)

    Wang, Jie; Nong, Xu-Hua; Amin, Muhammad; Qi, Shu-Hua

    2018-02-01

    Several ansamycins have been reported to inhibit bacterial biofilm formation and accelerate the eradication of developed biofilms, but little is known about the effect of hygrocin C, an ansamycin, on bacterial biofilm formation. Here, hygrocin C was isolated from the marine-derived Streptomyces sp. SCSGAA 0027 and reported for the first time to be capable of inhibiting the biofilm formation of Staphylococcus aureus and Bacillus amyloliquefaciens SCSGAB0082 with the production of anti-microbial lipopeptides from South China Sea gorgonian Subergorgia suberosa at concentrations of less than minimum inhibitory concentrations. Moreover, hygrocin C also promoted the eradication of developed biofilms, affected the biofilm architecture, and lowered the extracellular polymeric matrix formation, cell motility, and surface hydrophobicity in B. amyloliquefaciens, which was in accordance with the inhibition of biofilm formation. Furthermore, transcriptome analysis revealed that hygrocin C altered the transcripts of several genes associated with bacterial chemotaxis and flagellar, two-component system and the synthesis of arginine and histidine, which are important for bacterial biofilm formation. In conclusion, hygrocin C could be used as a potential biofilm inhibitor against S. aureus and B. amyloliquefaciens. But further genetic investigations are needed to provide more details for elucidation of the molecular mechanisms responsible for the effects of hygrocin C on B. amyloliquefaciens biofilm formation.

  1. Biocompatible succinic acid-based polyesters for potential biomedical applications: fungal biofilm inhibition and mesenchymal stem cell growth

    Czech Academy of Sciences Publication Activity Database

    Jäger, Eliezer; Donato, R. K.; Perchacz, Magdalena; Jäger, Alessandro; Surman, František; Höcherl, Anita; Konefal, Rafal; Donato, K. Z.; Venturini, Cristina Garcia; Bergamo, V. Z.; Schrekker, H. S.; Fuentefria, A. M.; Raucci, M. G.; Ambrosio, L.; Štěpánek, Petr

    2015-01-01

    Roč. 5, č. 104 (2015), s. 85756-85766 ISSN 2046-2069 R&D Projects: GA MŠk(CZ) 7F14009; GA MPO(CZ) FR-TI4/625 Institutional support: RVO:61389013 Keywords : polyesters * coating of medical devices * fungal biofilm inhibition Subject RIV: EE - Microbiology, Virology Impact factor: 3.289, year: 2015

  2. Lectin-Like Molecules of Lactobacillus rhamnosus GG Inhibit Pathogenic Escherichia coli and Salmonella Biofilm Formation

    Science.gov (United States)

    Petrova, Mariya I.; Imholz, Nicole C. E.; Verhoeven, Tine L. A.; Balzarini, Jan; Van Damme, Els J. M.; Schols, Dominique; Vanderleyden, Jos; Lebeer, Sarah

    2016-01-01

    Objectives Increased antibiotic resistance has catalyzed the research on new antibacterial molecules and alternative strategies, such as the application of beneficial bacteria. Since lectin molecules have unique sugar-recognizing capacities, and pathogens are often decorated with sugars that affect their survival and infectivity, we explored whether lectins from the probiotic strain Lactobacillus rhamnosus GG have antipathogenic properties. Methods The genome sequence of L. rhamnosus GG was screened for the presence of lectin-like proteins. Two genes, LGG_RS02780 and LGG_RS02750, encoding for polypeptides with an N-terminal conserved L-type lectin domain were detected and designated Llp1 (lectin-like protein 1) and Llp2. The capacity of Llp1 and Llp2 to inhibit biofilm formation of various pathogens was investigated. Sugar specificity was determined by Sepharose beads assays and glycan array screening. Results The isolated lectin domains of Llp1 and Llp2 possess pronounced inhibitory activity against biofilm formation by various pathogens, including clinical Salmonella species and uropathogenic E. coli, with Llp2 being more active than Llp1. In addition, sugar binding assays with Llp1 and Llp2 indicate specificity for complex glycans. Both proteins are also involved in the adhesion capacity of L. rhamnosus GG to gastrointestinal and vaginal epithelial cells. Conclusions Lectins isolated from or expressed by beneficial lactobacilli could be considered promising bio-active ingredients for improved prophylaxis of urogenital and gastrointestinal infections. PMID:27537843

  3. Lectin-Like Molecules of Lactobacillus rhamnosus GG Inhibit Pathogenic Escherichia coli and Salmonella Biofilm Formation.

    Science.gov (United States)

    Petrova, Mariya I; Imholz, Nicole C E; Verhoeven, Tine L A; Balzarini, Jan; Van Damme, Els J M; Schols, Dominique; Vanderleyden, Jos; Lebeer, Sarah

    2016-01-01

    Increased antibiotic resistance has catalyzed the research on new antibacterial molecules and alternative strategies, such as the application of beneficial bacteria. Since lectin molecules have unique sugar-recognizing capacities, and pathogens are often decorated with sugars that affect their survival and infectivity, we explored whether lectins from the probiotic strain Lactobacillus rhamnosus GG have antipathogenic properties. The genome sequence of L. rhamnosus GG was screened for the presence of lectin-like proteins. Two genes, LGG_RS02780 and LGG_RS02750, encoding for polypeptides with an N-terminal conserved L-type lectin domain were detected and designated Llp1 (lectin-like protein 1) and Llp2. The capacity of Llp1 and Llp2 to inhibit biofilm formation of various pathogens was investigated. Sugar specificity was determined by Sepharose beads assays and glycan array screening. The isolated lectin domains of Llp1 and Llp2 possess pronounced inhibitory activity against biofilm formation by various pathogens, including clinical Salmonella species and uropathogenic E. coli, with Llp2 being more active than Llp1. In addition, sugar binding assays with Llp1 and Llp2 indicate specificity for complex glycans. Both proteins are also involved in the adhesion capacity of L. rhamnosus GG to gastrointestinal and vaginal epithelial cells. Lectins isolated from or expressed by beneficial lactobacilli could be considered promising bio-active ingredients for improved prophylaxis of urogenital and gastrointestinal infections.

  4. L-histidine inhibits biofilm formation and FLO11-associated phenotypes in Saccharomyces cerevisiae flor yeasts.

    Science.gov (United States)

    Bou Zeidan, Marc; Zara, Giacomo; Viti, Carlo; Decorosi, Francesca; Mannazzu, Ilaria; Budroni, Marilena; Giovannetti, Luciana; Zara, Severino

    2014-01-01

    Flor yeasts of Saccharomyces cerevisiae have an innate diversity of Flo11p which codes for a highly hydrophobic and anionic cell-wall glycoprotein with a fundamental role in biofilm formation. In this study, 380 nitrogen compounds were administered to three S. cerevisiae flor strains handling Flo11p alleles with different expression levels. S. cerevisiae strain S288c was used as the reference strain as it cannot produce Flo11p. The flor strains generally metabolized amino acids and dipeptides as the sole nitrogen source, although with some exceptions regarding L-histidine and histidine containing dipeptides. L-histidine completely inhibited growth and its effect on viability was inversely related to Flo11p expression. Accordingly, L-histidine did not affect the viability of the Δflo11 and S288c strains. Also, L-histidine dramatically decreased air-liquid biofilm formation and adhesion to polystyrene of the flor yeasts with no effect on the transcription level of the Flo11p gene. Moreover, L-histidine modified the chitin and glycans content on the cell-wall of flor yeasts. These findings reveal a novel biological activity of L-histidine in controlling the multicellular behavior of yeasts [corrected].

  5. Application of lipopeptide biosurfactant isolated from a halophile: Bacillus tequilensis CH for inhibition of biofilm.

    Science.gov (United States)

    Pradhan, Arun Kumar; Pradhan, Nilotpala; Mall, Gangotri; Panda, Himadri Tanaya; Sukla, Lala Behari; Panda, Prasanna Kumar; Mishra, Barada Kanta

    2013-11-01

    Biosurfactants are amphiphilic molecules having hydrophobic and hydrophilic moieties produced by various microorganisms. These molecules trigger the reduction of surface tension or interfacial tension in liquids. A biosurfactant-producing halophile was isolated from Lake Chilika, a brackish water lake of Odisha, India (19°41'39″N, 85°18'24″E). The halophile was identified as Bacillus tequilensis CH by biochemical tests and 16S rRNA gene sequencing and assigned accession no. KC851857 by GenBank. The biosurfactant produced by B. tequilensis CH was partially characterized as a lipopeptide using thin-layer chromatography, Fourier transform infrared spectroscopy, and nuclear magnetic resonance techniques. The minimum effective concentration of a biosurfactant for inhibition of pathogenic biofilm (Escherichia coli and Streptococcus mutans) on hydrophilic and hydrophobic surfaces was found to be 50 μg ml(-1). This finding has potential for a variety of applications.

  6. Inhibition of Staphylococcus epidermidis Biofilm Formation by Traditional Thai Herbal Recipes Used for Wound Treatment

    OpenAIRE

    Chusri, S.; Sompetch, K.; Mukdee, S.; Jansrisewangwong, S.; Srichai, T.; Maneenoon, K.; Limsuwan, S.; Voravuthikunchai, S. P.

    2012-01-01

    Development of biofilm is a key mechanism involved in Staphylococcus epidermidis virulence during device-associated infections. We aimed to investigate antibiofilm formation and mature biofilm eradication ability of ethanol and water extracts of Thai traditional herbal recipes including THR-SK004, THR-SK010, and THR-SK011 against S. epidermidis. A biofilm forming reference strain, S. epidermidis ATCC 35984 was employed as a model for searching anti-biofilm agents by MTT reduction assay. The r...

  7. Combinatorial Effects of Aromatic 1,3-Disubstituted Ureas and Fluoride on In vitro Inhibition of Streptococcus mutans Biofilm Formation.

    Science.gov (United States)

    Kaur, Gurmeet; Balamurugan, P; Uma Maheswari, C; Anitha, A; Princy, S Adline

    2016-01-01

    Dental caries occur as a result of disequilibrium between acid producing pathogenic bacteria and alkali generating commensal bacteria within a dental biofilm (dental plaque). Streptococcus mutans has been reported as a primary cariogenic pathogen associated with dental caries. Emergence of multidrug resistant as well as fluoride resistant strains of S. mutans due to over use of various antibiotics are a rising problem and prompted the researchers worldwide to search for alternative therapies. In this perspective, the present study was aimed to screen selective inhibitors against ComA, a bacteriocin associated ABC transporter, involved in the quorum sensing of S. mutans. In light of our present in silico findings, 1,3-disubstituted urea derivatives which had better affinity to ComA were chemically synthesized in the present study for in vitro evaluation of S. mutans biofilm inhibition. The results revealed that 1,3-disubstituted urea derivatives showed good biofilm inhibition. In addition, synthesized compounds exhibited potent synergy with a very low concentration of fluoride (31.25-62.5 ppm) in inhibiting the biofilm formation of S. mutans without affecting the bacterial growth. Further, the results were supported by confocal laser scanning microscopy. On the whole, from our experimental results we conclude that the combinatorial application of fluoride and disubstituted ureas has a potential synergistic effect which has a promising approach in combating multidrug resistant and fluoride resistant S. mutans in dental caries management.

  8. Inhibition of biofilm development of uropathogens by curcumin - an anti-quorum sensing agent from Curcuma longa.

    Science.gov (United States)

    Packiavathy, Issac Abraham Sybiya Vasantha; Priya, Selvam; Pandian, Shunmugiah Karutha; Ravi, Arumugam Veera

    2014-04-01

    Urinary tract infection is caused primarily by the quorum sensing (QS)-dependent biofilm forming ability of uropathogens. In the present investigation, an anti-quorum sensing (anti-QS) agent curcumin from Curcuma longa (turmeric) was shown to inhibit the biofilm formation of uropathogens, such as Escherichia coli, Pseudomonas aeruginosa PAO1, Proteus mirabilis and Serratia marcescens, possibly by interfering with their QS systems. The antibiofilm potential of curcumin on uropathogens as well as its efficacy in disturbing the mature biofilms was examined under light microscope and confocal laser scanning microscope. The treatment with curcumin was also found to attenuate the QS-dependent factors, such as exopolysaccharide production, alginate production, swimming and swarming motility of uropathogens. Furthermore, it was documented that curcumin enhanced the susceptibility of a marker strain and uropathogens to conventional antibiotics. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Inhibition of Candida albicans Biofilm Formation by the Synthetic Lactoferricin Derived Peptide hLF1-11

    Science.gov (United States)

    Morici, Paola; Fais, Roberta; Rizzato, Cosmeri

    2016-01-01

    The aim of this study was to evaluate the in vitro activity of the synthetic peptide hLF1-11 against biofilm produced by clinical isolates of Candida albicans with different fluconazole susceptibility. The antibiofilm activity of the peptide hLF1-11 was assessed in terms of reduction of biofilm cellular density, metabolic activity and sessile cell viability. The extent of morphogenesis in hLF1-11 treated and untreated biofilms was also investigated microscopically. Transcription levels of genes related to cell adhesion, hyphal development and extracellular matrix production were analysed by qRT-PCR in hLF1-11 treated and untreated biofilms. Exogenous dibutyryl-cAMP (db-cAMP) was used to rescue morphogenesis in cells exposed to the peptide. The results revealed that hLF1-11 exhibited an inhibitory effect on biofilm formation by all C. albicans isolates tested in a dose-dependent manner, regardless of their fluconazole susceptibility. Visual inspection of treated or untreated biofilm cells with an inverted microscope revealed a significant reduction in hyphal formation by hLF1-11 treated cells, as early as 3 hours of incubation. Moreover, hLF1-11 showed a reduced activity on preadherent cells. hLF1-11 induced the down-regulation of biofilm and hyphal-associated genes, which were predominantly regulated via the Ras1-cAMP-Efg1 pathway. Indeed, exogenous db-cAMP restored morphogenesis in hLF1-11 treated cells. The hLF1-11 peptide significantly inhibited biofilm formation by C. albicans mainly at early stages, interfering with biofilm cellular density and metabolic activity, and affected morphogenesis through the Ras1-cAMP-Efg1 pathway. Our findings provide the first evidence that hLF1-11 could represent a potential candidate for the prevention of biofilm formation by C. albicans. PMID:27902776

  10. Inhibition of Candida albicans Biofilm Formation by the Synthetic Lactoferricin Derived Peptide hLF1-11.

    Directory of Open Access Journals (Sweden)

    Paola Morici

    Full Text Available The aim of this study was to evaluate the in vitro activity of the synthetic peptide hLF1-11 against biofilm produced by clinical isolates of Candida albicans with different fluconazole susceptibility. The antibiofilm activity of the peptide hLF1-11 was assessed in terms of reduction of biofilm cellular density, metabolic activity and sessile cell viability. The extent of morphogenesis in hLF1-11 treated and untreated biofilms was also investigated microscopically. Transcription levels of genes related to cell adhesion, hyphal development and extracellular matrix production were analysed by qRT-PCR in hLF1-11 treated and untreated biofilms. Exogenous dibutyryl-cAMP (db-cAMP was used to rescue morphogenesis in cells exposed to the peptide. The results revealed that hLF1-11 exhibited an inhibitory effect on biofilm formation by all C. albicans isolates tested in a dose-dependent manner, regardless of their fluconazole susceptibility. Visual inspection of treated or untreated biofilm cells with an inverted microscope revealed a significant reduction in hyphal formation by hLF1-11 treated cells, as early as 3 hours of incubation. Moreover, hLF1-11 showed a reduced activity on preadherent cells. hLF1-11 induced the down-regulation of biofilm and hyphal-associated genes, which were predominantly regulated via the Ras1-cAMP-Efg1 pathway. Indeed, exogenous db-cAMP restored morphogenesis in hLF1-11 treated cells. The hLF1-11 peptide significantly inhibited biofilm formation by C. albicans mainly at early stages, interfering with biofilm cellular density and metabolic activity, and affected morphogenesis through the Ras1-cAMP-Efg1 pathway. Our findings provide the first evidence that hLF1-11 could represent a potential candidate for the prevention of biofilm formation by C. albicans.

  11. Vizantin inhibits bacterial adhesion without affecting bacterial growth and causes Streptococcus mutans biofilm to detach by altering its internal architecture.

    Science.gov (United States)

    Takenaka, Shoji; Oda, Masataka; Domon, Hisanori; Ohsumi, Tatsuya; Suzuki, Yuki; Ohshima, Hayato; Yamamoto, Hirofumi; Terao, Yutaka; Noiri, Yuichiro

    2016-11-11

    An ideal antibiofilm strategy is to control both in the quality and quantity of biofilm while maintaining the benefits derived from resident microflora. Vizantin, a recently developed immunostimulating compound, has also been found to have antibiofilm property. This study evaluated the influence on biofilm formation of Streptococcus mutans in the presence of sulfated vizantin and biofilm development following bacterial adhesion on a hydroxyapatite disc coated with sulfated vizantin. Supplementation with sulfated vizantin up to 50 μM did not affect either bacterial growth or biofilm formation, whereas 50 μM sulfated vizantin caused the biofilm to readily detach from the surface. Sulfated vizantin at the concentration of 50 μM upregulated the expression of the gtfB and gtfC genes, but downregulated the expression of the gtfD gene, suggesting altered architecture in the biofilm. Biofilm development on the surface coated with sulfated vizantin was inhibited depending on the concentration, suggesting prevention from bacterial adhesion. Among eight genes related to bacterial adherence in S. mutans, expression of gtfB and gtfC was significantly upregulated, whereas the expression of gtfD, GbpA and GbpC was downregulated according to the concentration of vizantin, especially with 50 μM vizantin by 0.8-, 0.4-, and 0.4-fold, respectively. These findings suggest that sulfated vizantin may cause structural degradation as a result of changing gene regulation related to bacterial adhesion and glucan production of S. mutans. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Inhibition of Nitzschia ovalis biofilm settlement by a bacterial bioactive compound through alteration of EPS and epiphytic bacteria

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    Claudia D. Infante

    2018-05-01

    Full Text Available Background: Marine ecosystems contain benthic microalgae and bacterial species that are capable of secreting extracellular polymeric substances (EPS, suggesting that settlement of these microorganisms can occur on submerged surfaces, a key part of the first stage of biofouling. Currently, anti-fouling treatments that help control this phenomenon involve the use of biocides or antifouling paints that contain heavy metals, which over a long period of exposure can spread to the environment. The bacterium Alteromonas sp. Ni1-LEM has an inhibitory effect on the adhesion of Nitzschia ovalis, an abundant diatom found on submerged surfaces. Results: We evaluated the effect of the bioactive compound secreted by this bacterium on the EPS of biofilms and associated epiphytic bacteria. Three methods of EPS extraction were evaluated to determine the most appropriate and efficient methodology based on the presence of soluble EPS and the total protein and carbohydrate concentrations. Microalgae were cultured with the bacterial compound to evaluate its effect on EPS secretion and variations in its protein and carbohydrate concentrations. An effect of the bacterial supernatant on EPS was observed by assessing biofilm formation and changes in the concentration of proteins and carbohydrates present in the biofilm. Conclusions: These results indicate that a possible mechanism for regulating biofouling could be through alteration of biofilm EPS and alteration of the epiphytic bacterial community associated with the microalga.How to cite: Infante, C.D., Castillo, F., Pérez, V., et al. Inhibition of Nitzschia ovalis biofilm settlement by a bacterial bioactive compound through alteration of EPS and epiphytic bacteria. Electron J Biotechnol 2018;33 https://doi.org/10.1016/j.ejbt.2018.03.002. Keywords: Anti-fouling, Benthic microalgae, Biofilm, Biofouling, Epiphytic bacterial community, EPS, Marine ecosystems, Metagenomic, Nitzschia ovalis, Settlement inhibition

  13. Zerovalent bismuth nanoparticles inhibit Streptococcus mutans growth and formation of biofilm

    Directory of Open Access Journals (Sweden)

    Hernandez-Delgadillo R

    2012-04-01

    Full Text Available Rene Hernandez-Delgadillo1, Donaji Velasco-Arias2, David Diaz2, Katiushka Arevalo-Niño1, Marianela Garza-Enriquez1, Myriam A De la Garza-Ramos1, Claudio Cabral-Romero11Instituto de Biotecnologia, Centro de Investigacion y Desarrollo en Ciencias de la Salud, CIDICS, Facultad de Odontologia, Universidad Autonoma de Nuevo Leon, UANL, Monterrey, Nuevo Leon, 2Facultad de Quimica, Universidad Nacional Autonoma de Mexico, Distrito Federal, MexicoBackground and methods: Despite continuous efforts, the increasing prevalence of resistance among pathogenic bacteria to common antibiotics has become one of the most significant concerns in modern medicine. Nanostructured materials are used in many fields, including biological sciences and medicine. While some bismuth derivatives has been used in medicine to treat vomiting, nausea, diarrhea, and stomach pain, the biocidal activity of zerovalent bismuth nanoparticles has not yet been studied. The objective of this investigation was to analyze the antimicrobial activity of bismuth nanoparticles against oral bacteria and their antibiofilm capabilities.Results: Our results showed that stable colloidal bismuth nanoparticles had 69% antimicrobial activity against Streptococcus mutans growth and achieved complete inhibition of biofilm formation. These results are similar to those obtained with chlorhexidine, the most commonly used oral antiseptic agent. The minimal inhibitory concentration of bismuth nanoparticles that interfered with S. mutans growth was 0.5 mM.Conclusion: These results suggest that zerovalent bismuth nanoparticles could be an interesting antimicrobial agent to be incorporated into an oral antiseptic preparation.Keywords: zerovalent bismuth nanoparticles, antimicrobial agent, biofilm, Streptococcus mutans

  14. Engineered chimeric peptides with antimicrobial and titanium-binding functions to inhibit biofilm formation on Ti implants.

    Science.gov (United States)

    Geng, Hongjuan; Yuan, Yang; Adayi, Aidina; Zhang, Xu; Song, Xin; Gong, Lei; Zhang, Xi; Gao, Ping

    2018-01-01

    Titanium (Ti) implants have been commonly used in oral medicine. However, despite their widespread clinical application, these implants are susceptible to failure induced by microbial infection due to bacterial biofilm formation. Immobilization of chimeric peptides with antibacterial properties on the Ti surface may be a promising antimicrobial approach to inhibit biofilm formation. Here, chimeric peptides were designed by connecting three sequences (hBD-3-1/2/3) derived from human β-defensin-3 (hBD-3) with Ti-binding peptide-l (TBP-l: RKLPDAGPMHTW) via a triple glycine (G) linker to modify Ti surfaces. Using X-ray photoelectron spectroscopy (XPS), the properties of individual domains of the chimeric peptides were evaluated for their binding activity toward the Ti surface. The antimicrobial and anti-biofilm efficacy of the peptides against initial settlers, Streptococcus oralis (S. oralis), Streptococcus gordonii (S. gordonii) and Streptococcus sanguinis (S. sanguinis), was evaluated with confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Transmission electron microscopy (TEM) and real-time quantitative PCR (qRT-PCR) were used to study cell membrane changes and the underlying antimicrobial mechanism. Compared with the other two peptides, TBP-1-GGG-hBD3-3 presented stronger antibacterial activity and remained stable in saliva and serum. Therefore, it was chosen as the best candidate to modify Ti surfaces in this study. This peptide inhibited the growth of initial streptococci and biofilm formation on Ti surfaces with no cytotoxicity to MC3T3-E1 cells. Disruption of the integrity of bacterial membranes and decreased expression of adhesion protein genes from S. gordonii revealed aspects of the antibacterial mechanism of TBP-1-GGG-hBD3-3. We conclude that engineered chimeric peptides with antimicrobial activity provide a potential solution for inhibiting biofilm formation on Ti surfaces to reduce or prevent the occurrence of peri

  15. Hibiscus sabdariffa extract inhibits in vitro biofilm formation capacity of Candida albicans isolated from recurrent urinary tract infections.

    Science.gov (United States)

    Alshami, Issam; Alharbi, Ahmed E

    2014-02-01

    To explore the prevention of recurrent candiduria using natural based approaches and to study the antimicrobial effect of Hibiscus sabdariffa (H. sabdariffa) extract and the biofilm forming capacity of Candida albicans strains in the present of the H. sabdariffa extract. In this particular study, six strains of fluconazole resistant Candida albicans isolated from recurrent candiduria were used. The susceptibility of fungal isolates, time-kill curves and biofilm forming capacity in the present of the H. sabdariffa extract were determined. Various levels minimum inhibitory concentration of the extract were observed against all the isolates. Minimum inhibitory concentration values ranged from 0.5 to 2.0 mg/mL. Time-kill experiment demonstrated that the effect was fungistatic. The biofilm inhibition assay results showed that H. sabdariffa extract inhibited biofilm production of all the isolates. The results of the study support the potential effect of H. sabdariffa extract for preventing recurrent candiduria and emphasize the significance of the plant extract approach as a potential antifungal agent.

  16. Streptococcal adhesin SspA/B analogue peptide inhibits adherence and impacts biofilm formation of Streptococcus mutans.

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    Tatsuro Ito

    Full Text Available Streptococcus mutans, the major causative agent of dental caries, adheres to tooth surfaces via the host salivary glycoprotein-340 (gp340. This adherence can be competitively inhibited by peptides derived from the SspA/B adhesins of Streptococcus gordonii, a human commensal microbe that competes for the same binding sites. Ssp(A4K-A11K, a double-lysine substituted SspA/B peptide analogue, has been shown to exhibit superior in vitro binding affinity for a gp340-derived peptide (SRCRP2, suggesting that Ssp(A4K-A11K may be of clinical interest. In the present work, we tested the inhibitory effects of Ssp(A4K-A11K on adherence and biofilm formation of S. mutans by reconstructing an artificial oral environment using saliva-coated polystyrene plates and hydroxyapatite disks. Bacterial adherence (adherence period: 1 h was assessed by an enzyme-linked immunosorbent assay using biotinylated bacterial cells. Biofilm formation (periods: 8, 11, or 14 h was assessed by staining and imaging of the sessile cells, or by recovering biofilm cells and plating for cell counts. The pH values of the culture media were measured as a biofilm acidogenicity indicator. Bactericidality was measured by loss of optical density during culturing in the presence of the peptide. We observed that 650 μM Ssp(A4K-A11K significantly inhibited adherence of S. mutans to saliva-coated polystyrene; a similar effect was seen on bacterial affinity for SRCRP2. Ssp(A4K-A11K had lesser effects on the adherence of commensal streptococci. Pretreatment of polystyrene and hydroxyapatite with 650 μM Ssp(A4K-A11K significantly attenuated biofilm formation, whether tested with glucose- or sucrose-containing media. The SspA/B peptide's activity did not reflect bactericidality. Strikingly, pH in Ssp-treated 8-h (6.8 ± 0.06 and 11-h (5.5 ± 0.06 biofilms showed higher values than the critical pH. Thus, Ssp(A4K-A11K acts by inhibiting bacterial adherence and cariogrnic biofilm formation. We further

  17. Biogenic synthesis of Zinc oxide nanostructures from Nigella sativa seed: Prospective role as food packaging material inhibiting broad-spectrum quorum sensing and biofilm.

    Science.gov (United States)

    Al-Shabib, Nasser A; Husain, Fohad Mabood; Ahmed, Faheem; Khan, Rais Ahmad; Ahmad, Iqbal; Alsharaeh, Edreese; Khan, Mohd Shahnawaz; Hussain, Afzal; Rehman, Md Tabish; Yusuf, Mohammad; Hassan, Iftekhar; Khan, Javed Masood; Ashraf, Ghulam Md; Alsalme, Ali Mohammed; Al-Ajmi, Mohamed F; Tarasov, Vadim V; Aliev, Gjumrakch

    2016-12-05

    Bacterial spoilage of food products is regulated by density dependent communication system called quorum sensing (QS). QS control biofilm formation in numerous food pathogens and Biofilms formed on food surfaces act as carriers of bacterial contamination leading to spoilage of food and health hazards. Agents inhibiting or interfering with bacterial QS and biofilm are gaining importance as a novel class of next-generation food preservatives/packaging material. In the present study, Zinc nanostructures were synthesised using Nigella sativa seed extract (NS-ZnNPs). Synthesized nanostructures were characterized hexagonal wurtzite structure of size ~24 nm by UV-visible, XRD, FTIR and TEM. NS-ZnNPs demonstrated broad-spectrum QS inhibition in C. violaceum and P. aeruginosa biosensor strains. Synthesized nanostructures inhibited QS regulated functions of C. violaceum CVO26 (violacein) and elastase, protease, pyocyanin and alginate production in PAO1 significantly. NS-ZnNPs at sub-inhibitory concentrations inhibited the biofilm formation of four-food pathogens viz. C. violaceum 12472, PAO1, L. monocytogenes, E. coli. Moreover, NS-ZnNPs was found effective in inhibiting pre-formed mature biofilms of the four pathogens. Therefore, the broad-spectrum inhibition of QS and biofilm by biogenic Zinc oxide nanoparticles and it is envisaged that these nontoxic bioactive nanostructures can be used as food packaging material and/or as food preservative.

  18. Inhibition of Steptococcus mutans biofilm formation by extracts of Tenacibaculum sp. 20J, a bacterium with wide-spectrum quorum quenching activity

    Science.gov (United States)

    Muras, Andrea; Mayer, Celia; Romero, Manuel; Camino, Tamara; Ferrer, Maria D.; Mira, Alex; Otero, Ana

    2018-01-01

    ABSTRACT Background: Previous studies have suggested the quorum sensing signal AI-2 as a potential target to prevent the biofilm formation by Streptococcus mutans, a pathogen involved in tooth decay. Objective: To obtain inhibition of biofilm formation by S. mutans by extracts obtained from the marine bacterium Tenacibaculum sp. 20J interfering with the AI-2 quorum sensing system. Design: The AI-2 inhibitory activity was tested with the biosensors Vibrio harveyi BB170 and JMH597. S. mutans ATCC25175 biofilm formation was monitored using impedance real-time measurements with the xCELLigence system®, confocal laser microscopy, and the crystal violet quantification method. Results: The addition of the cell extract from Tenacibaculum sp. 20J reduced biofilm formation in S. mutans ATCC25175 by 40–50% compared to the control without significantly affecting growth. A decrease of almost 40% was also observed in S. oralis DSM20627 and S. dentisani 7747 biofilms. Conclusions: The ability of Tenacibaculum sp. 20J to interfere with AI-2 and inhibit biofilm formation in S. mutans was demonstrated. The results indicate that the inhibition of quorum sensing processes may constitute a suitable strategy for inhibiting dental plaque formation, although additional experiments using mixed biofilm models would be required. PMID:29410771

  19. Bismuth oxide aqueous colloidal nanoparticles inhibit Candida albicans growth and biofilm formation

    Directory of Open Access Journals (Sweden)

    Hernandez-Delgadillo R

    2013-04-01

    Full Text Available Rene Hernandez-Delgadillo,1 Donaji Velasco-Arias,3 Juan Jose Martinez-Sanmiguel,2 David Diaz,3 Inti Zumeta-Dube,3 Katiushka Arevalo-Niño,1 Claudio Cabral-Romero2 1Facultad de Ciencias Biológicas, Instituto de Biotecnologia, Universidad Autonoma de Nuevo Leon, UANL, Monterrey, Mexico; 2Facultad de Odontología, Universidad Autonoma de Nuevo Leon, UANL, Monterrey, México; 3Facultad de Quimica, Universidad Nacional Autonoma de Mexico, UNAM, Distrito Federal, México Abstract: Multiresistance among microorganisms to common antimicrobials has become one of the most significant concerns in modern medicine. Nanomaterials are a new alternative to successfully treat the multiresistant microorganisms. Nanostructured materials are used in many fields, including biological sciences and medicine. Recently, it was demonstrated that the bactericidal activity of zero-valent bismuth colloidal nanoparticles inhibited the growth of Streptococcus mutans; however the antimycotic potential of bismuth nanostructured derivatives has not yet been studied. The main objective of this investigation was to analyze the fungicidal activity of bismuth oxide nanoparticles against Candida albicans, and their antibiofilm capabilities. Our results showed that aqueous colloidal bismuth oxide nanoparticles displayed antimicrobial activity against C. albicans growth (reducing colony size by 85% and a complete inhibition of biofilm formation. These results are better than those obtained with chlorhexidine, nystatin, and terbinafine, the most effective oral antiseptic and commercial antifungal agents. In this work, we also compared the antimycotic activities of bulk bismuth oxide and bismuth nitrate, the precursor metallic salt. These results suggest that bismuth oxide colloidal nanoparticles could be a very interesting candidate as a fungicidal agent to be incorporated into an oral antiseptic. Additionally, we determined the minimum inhibitory concentration for the synthesized

  20. Systematic Exploration of Natural and Synthetic Flavonoids for the Inhibition of Staphylococcus aureus Biofilms

    Science.gov (United States)

    Manner, Suvi; Skogman, Malena; Goeres, Darla; Vuorela, Pia; Fallarero, Adyary

    2013-01-01

    When single-cell (or suspended) bacteria switch into the biofilm lifestyle, they become less susceptible to antimicrobials, imposing the need for anti-biofilms research. Flavonoids are among the most extensively studied natural compounds with an unprecedented amount of bioactivity claims. Most studies focus on the antibacterial effects against suspended cells; fewer reports have researched their anti-biofilm properties. Here, a high throughput phenotypic platform was utilized to screen for the inhibitory activity of 500 flavonoids, including natural and synthetic derivatives, against Staphylococcus aureus biofilms. Since discrepancies among results from earlier antibacterial studies on flavonoids had been noted, the current study aimed to minimize sources of variations. After the first screen, flavonoids were classified as inactive (443), moderately active (47) or highly active (10). Further, exclusion criteria combining bioactivity and selectivity identified two synthetic flavans as the most promising. The body of data reported here serves three main purposes. First, it offers an improved methodological workflow for anti-biofilm screens of chemical libraries taking into account the (many times ignored) connections between anti-biofilm and antibacterial properties. This is particularly relevant for the study of flavonoids and other natural products. Second, it provides a large and freely available anti-biofilm bioactivity dataset that expands the knowledge on flavonoids and paves the way for future structure-activity relationship studies and structural optimizations. Finally, it identifies two new flavans that can successfully act on biofilms, as well as on suspended bacteria and represent more feasible antibacterial candidates. PMID:24071942

  1. Pseudomonas aeruginosa extracellular products inhibit staphylococcal growth, and disrupt established biofilms produced by Staphylococcus epidermidis

    DEFF Research Database (Denmark)

    Qin, Zhiqiang; Yang, Liang; Qu, Di

    2009-01-01

    Multiple bacterial species often coexist as communities, and compete for environmental resources. Here, we describe how an opportunistic pathogen, Pseudomonas aeruginosa, uses extracellular products to interact with the nosocomial pathogen Staphylococcus epidermidis. S. epidermidis biofilms and p...... of a novel strategy for controlling S. epidermidis biofilms....

  2. Quinoline based furanones and their nitrogen analogues: Docking, synthesis and biological evaluation

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    Sukhbir Lal Khokra

    2016-11-01

    Full Text Available A small library of twenty-four quinoline based butenolides also known as furanones and their nitrogen analogues was prepared by using two different aroylpropionic acids, viz. 3-(2-naphthoylpropionic acid (3 and 3-(biphenyl-4-ylpropionic acid (4, as starting materials. The 3-aroylpropionic acids were reacted with different 6-substituted-2-chloroquinolin-3-carbaldehydes (2a–d to obtain the corresponding furan-2(3H-ones (5a–h. The purified and characterized furanones were then converted into their corresponding 2(3H-pyrrolones (6a–h and N-benzyl-pyrrol-2(3H-ones (7a–h. The antimicrobial activities of the title compounds were evaluated against two strains of each Gram +ve (Staphylococcus aureus and Bacillus subtilis, Gram −ve bacteria (Escherichia coli and Pseudomonas aeruginosa and against fungal strains of Aspergillus niger and Aspergillus flavus. In vivo anti-inflammatory potential of the title compounds was investigated by standard method. Majority of the compounds showed significant antibacterial activity against both the Gram +ve strains. Eight most potent anti-inflammatory compounds (5b, 5d, 5h, 6b, 7b, 7d, 7f, 7h which exhibited >53% inhibition in edema, were also screened for their in vivo analgesic activity. All the tested compounds were found to have significant reduction in ulcerogenic action but only three compounds (5d, 5h and 7h showed comparable analgesic activity to standard drug, diclofenac. The results were also validated using in silico approach and maximum mol doc score was obtained for compounds 7a–h. On comparing the in vivo and in silico anti-inflammatory results of synthesized compounds, N-benzyl pyrrolones (7a–h emerged as the potent anti-inflammatory agents. It was also observed that compounds that possess electron withdrawing group such as Cl or NO2 are more biologically active.

  3. Leaf Extracts of Mangifera indica L. Inhibit Quorum Sensing – Regulated Production of Virulence Factors and Biofilm in Test Bacteria

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    Iqbal Ahmad

    2017-04-01

    Full Text Available Quorum sensing (QS is a global gene regulatory mechanism in bacteria for various traits including virulence factors. Disabling QS system with anti-infective agent is considered as a potential strategy to prevent bacterial infection. Mangifera indica L. (mango has been shown to possess various biological activities including anti-QS. This study investigates the efficacy of leaf extracts on QS-regulated virulence factors and biofilm formation in Gram negative pathogens. Mango leaf (ML extract was tested for QS inhibition and QS-regulated virulence factors using various indicator strains. It was further correlated with the biofilm inhibition and confirmed by electron microscopy. Phytochemical analysis was carried out using ultra performance liquid chromatography (UPLC and gas chromatography–mass spectrometry (GC-MS analysis. In vitro evaluation of anti-QS activity of ML extracts against Chromobacterium violaceum revealed promising dose-dependent interference in violacein production, by methanol extract. QS inhibitory activity is also demonstrated by reduction in elastase (76%, total protease (56%, pyocyanin (89%, chitinase (55%, exopolysaccharide production (58% and swarming motility (74% in Pseudomonas aeruginosa PAO1 at 800 μg/ml concentration. Biofilm formation by P. aeruginosa PAO1 and Aeromonas hydrophila WAF38 was reduced considerably (36–82% over control. The inhibition of biofilm was also observed by scanning electron microscopy. Moreover, ML extracts significantly reduced mortality of Caenorhabditis elegans pre-infected with PAO1 at the tested concentration. Phytochemical analysis of active extracts revealed very high content of phenolics in methanol extract and a total of 14 compounds were detected by GC-MS and UPLC. These findings suggest that phytochemicals from the ML could provide bioactive anti-infective and needs further investigation to isolate and uncover their therapeutic efficacy.

  4. Leaf Extracts of Mangifera indica L. Inhibit Quorum Sensing – Regulated Production of Virulence Factors and Biofilm in Test Bacteria

    Science.gov (United States)

    Husain, Fohad M.; Ahmad, Iqbal; Al-thubiani, Abdullah S.; Abulreesh, Hussein H.; AlHazza, Ibrahim M.; Aqil, Farrukh

    2017-01-01

    Quorum sensing (QS) is a global gene regulatory mechanism in bacteria for various traits including virulence factors. Disabling QS system with anti-infective agent is considered as a potential strategy to prevent bacterial infection. Mangifera indica L. (mango) has been shown to possess various biological activities including anti-QS. This study investigates the efficacy of leaf extracts on QS-regulated virulence factors and biofilm formation in Gram negative pathogens. Mango leaf (ML) extract was tested for QS inhibition and QS-regulated virulence factors using various indicator strains. It was further correlated with the biofilm inhibition and confirmed by electron microscopy. Phytochemical analysis was carried out using ultra performance liquid chromatography (UPLC) and gas chromatography–mass spectrometry (GC-MS) analysis. In vitro evaluation of anti-QS activity of ML extracts against Chromobacterium violaceum revealed promising dose-dependent interference in violacein production, by methanol extract. QS inhibitory activity is also demonstrated by reduction in elastase (76%), total protease (56%), pyocyanin (89%), chitinase (55%), exopolysaccharide production (58%) and swarming motility (74%) in Pseudomonas aeruginosa PAO1 at 800 μg/ml concentration. Biofilm formation by P. aeruginosa PAO1 and Aeromonas hydrophila WAF38 was reduced considerably (36–82%) over control. The inhibition of biofilm was also observed by scanning electron microscopy. Moreover, ML extracts significantly reduced mortality of Caenorhabditis elegans pre-infected with PAO1 at the tested concentration. Phytochemical analysis of active extracts revealed very high content of phenolics in methanol extract and a total of 14 compounds were detected by GC-MS and UPLC. These findings suggest that phytochemicals from the ML could provide bioactive anti-infective and needs further investigation to isolate and uncover their therapeutic efficacy. PMID:28484444

  5. Pitting corrosion inhibition of aluminum 2024 by Bacillus biofilms secreting polyaspartate or gamma-polyglutamate.

    Science.gov (United States)

    Ornek, D; Jayaraman, A; Syrett, B C; Hsu, C-H; Mansfeld, F B; Wood, T K

    2002-04-01

    Pitting corrosion of aluminum 2024 in Luria Bertani medium was reduced by the secretion of anionic peptides by engineered and natural Bacillus biofilms and was studied in continuous reactors using electrochemical impedance spectroscopy. Compared to sterile controls, pitting was reduced dramatically by the presence of the biofilms. The secretion of a 20 amino acid polyaspartate peptide by an engineered Bacillus subtilis WB600/pBE92-Asp biofilm slightly reduced the corrosion rate of the passive aluminum alloy at pH 6.5; however, the secretion of gamma-polyglutamate by a Bacillus licheniformis biofilm reduced the corrosion rate by 90% (compared to the B. subtilis WB600/pBE92 biofilm which did not secrete polyaspartate or gamma-polyglutamate). The corrosion potential ( E(corr)) of aluminum 2024 was increased by about 0.15-0.44 V due to the formation of B. subtilis and B. licheniformis biofilms as compared to sterile controls. The increase of E(corr) and the observed prevention of pitting indicate that the pitting potential ( E(pit)) had increased. This result and the further decrease of corrosion rates for the passive aluminum alloy suggest that the rate of the anodic metal dissolution reaction was reduced by an inhibitor produced by the biofilms. Purified gamma-polyglutamate also decreased the corrosion rates of aluminum 2024.

  6. Lavage with allicin in combination with vancomycin inhibits biofilm formation by Staphylococcus epidermidis in a rabbit model of prosthetic joint infection.

    Directory of Open Access Journals (Sweden)

    Haohan Zhai

    Full Text Available BACKGROUND AND AIM: The present anti-infection strategy for prosthetic joint infections (PJI includes the use of antibiotics and surgical treatments, but the bacterial eradication rates are still low. One of the major challenges is the formation of biofilm causing poor bacterial eradication. Recently it has been reported that allicin (diallyl thiosulphinate, an antibacterial principle of garlic, can inhibit bacteria adherence and prevent biofilm formation in vitro. However, whether allicin could inhibit biofilm formation in vivo is unknown. The aim of this study was to investigate the effects of allicin on biofilm formation, and whether allicin could potentiate the bactericidal effect of vancomycin in a rabbit PJI model. METHODS: A sterile stainless-steel screw with a sterile ultra-high molecular weight polyethylene washer was inserted into the lateral femoral condyle of the right hind knee joint of rabbit, and 1 mL inoculum containing 104 colony-forming units of Staphylococcus epidermidis was inoculated into the knee joint (n = 32. Fourteen days later, rabbits randomly received one of the following 4 treatments using continuous lavages: normal saline, vancomycin (20 mcg/mL, allicin (4 mg/L, or allicin (4 mg/L plus vancomycin (20 mcg/mL. Three days later, the washer surface biofilm formation was examined by scanning electron microscopy (SEM. The bacterial counts within the biofilm of implanted screws were determined by bacterial culture. RESULTS: The lowest number of viable bacterial counts of Staphylococcus epidermidis recovered from the biofilm was in the rabbits treated with allicin plus vancomycin (P<0.01 vs. all other groups. The biofilm formation was significantly reduced or undetectable by SEM in rabbits receiving allicin or allicin plus vancomycin. CONCLUSION: Intra-articular allicincan inhibit biofilm formation and enhance the bactericidal effect of vancomycin on implant surface in vivo. Allicin in combination with vancomycin may be

  7. Inhibition of Steptococcus mutans biofilm formation by extracts of Tenacibaculum sp. 20J, a bacterium with wide-spectrum quorum quenching activity

    OpenAIRE

    Muras, Andrea; Mayer, Celia; Romero, Manuel; Camino, Tamara; Ferrer, Maria D.; Mira, Alex; Otero, Ana

    2018-01-01

    ABSTRACT Background: Previous studies have suggested the quorum sensing signal AI-2 as a potential target to prevent the biofilm formation by Streptococcus mutans, a pathogen involved in tooth decay. Objective: To obtain inhibition of biofilm formation by S. mutans by extracts obtained from the marine bacterium Tenacibaculum sp. 20J interfering with the AI-2 quorum sensing system. Design: The AI-2 inhibitory activity was tested with the biosensors Vibrio harveyi BB170 and JMH597. S. mutans AT...

  8. Natural 4-Hydroxy-2,5-dimethyl-3(2H)-furanone (Furaneol®)

    OpenAIRE

    Wilfried Schwab

    2013-01-01

    4-Hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF, furaneol®) and its methyl ether 2,5-dimethyl-4-methoxy-3(2H)-furanone (DMMF) are import aroma chemicals and are considered key flavor compounds in many fruit. Due to their attractive sensory properties they are highly appreciated by the food industry. In fruits 2,5-dimethyl-3(2H)-furanones are synthesized by a series of enzymatic steps whereas HDMF is also a product of the Maillard reaction. Numerous methods for the synthetic preparation of these c...

  9. In Situ Identification and Stratification of Monochloramine Inhibition Effects on Nitrifying Biofilms as Determined by the Use of Microelectrodes

    Science.gov (United States)

    The nitrifying biofilm grown in an annular biofilm reactor and the microbial deactivation achieved after monochloramine treatment were investigated using microelectrodes. The nitrifying biofilm ammonium microprofile was measured and the effect of monochloramine on nitrifying bio...

  10. Physiologic actions of zinc related to inhibition of acid and alkali production by oral streptococci in suspensions and biofilms.

    Science.gov (United States)

    Phan, T-N; Buckner, T; Sheng, J; Baldeck, J D; Marquis, R E

    2004-02-01

    Zinc is a known inhibitor of acid production by mutans streptococci. Our primary objective was to extend current knowledge of the physiologic bases for this inhibition and also for zinc inhibition of alkali production by Streptococcus rattus FA-1 and Streptococcus salivarius ATCC 13419. Zinc at concentrations as low as 0.01-0.1 mm not only inhibited acid production by cells of Streptococcus mutans GS-5 in suspensions or in biofilms but also sensitized glycolysis by intact cells to acidification. Zinc reversibly inhibited the F-ATPase of permeabilized cells of S. mutans with a 50% inhibitory concentration of about 1 mm for cells in suspensions. Zinc reversibly inhibited the phosphoenolpyruvate: sugar phosphotransferase system with 50% inhibition at about 0.3 mm ZnSO4, or about half that concentration when the zinc-citrate chelate was used. The reversibility of these inhibitory actions of zinc correlates with findings that it is mainly bacteriostatic rather than bactericidal. Zinc inhibited alkali production from arginine or urea and was a potent enzyme inhibitor for arginine deiminase of S. rattus FA-1 and for urease of S. salivarius. In addition, zinc citrate at high levels of 10-20 mm was weakly bactericidal.

  11. Nitrite accumulation from simultaneous free-ammonia and free-nitrous-acid inhibition and oxygen limitation in a continuous-flow biofilm reactor.

    Science.gov (United States)

    Park, Seongjun; Chung, Jinwook; Rittmann, Bruce E; Bae, Wookeun

    2015-01-01

    To achieve nitrite accumulation for shortcut biological nitrogen removal (SBNR) in a biofilm process, we explored the simultaneous effects of oxygen limitation and free ammonia (FA) and free nitrous acid (FNA) inhibition in the nitrifying biofilm. We used the multi-species nitrifying biofilm model (MSNBM) to identify conditions that should or should not lead to nitrite accumulation, and evaluated the effectiveness of those conditions with experiments in continuous flow biofilm reactors (CFBRs). CFBR experiments were organized into four sets with these expected outcomes based on the MSNBM as follows: (i) Control, giving full nitrification; (ii) oxygen limitation, giving modest long-term nitrite build up; (iii) FA inhibition, giving no long-term nitrite accumulation; and (iv) FA inhibition plus oxygen limitation, giving major long-term nitrite accumulation. Consistent with MSNBM predictions, the experimental results showed that nitrite accumulated in sets 2-4 in the short term, but long-term nitrite accumulation was maintained only in sets 2 and 4, which involved oxygen limitation. Furthermore, nitrite accumulation was substantially greater in set 4, which also included FA inhibition. However, FA inhibition (and accompanying FNA inhibition) alone in set 3 did not maintained long-term nitrite accumulation. Nitrite-oxidizing bacteria (NOB) activity batch tests confirmed that little NOB or only a small fraction of NOB were present in the biofilms for sets 4 and 2, respectively. The experimental data supported the previous modeling results that nitrite accumulation could be achieved with a lower ammonium concentration than had been required for a suspended-growth process. Additional findings were that the biofilm exposed to low dissolved oxygen (DO) limitation and FA inhibition was substantially denser and probably had a lower detachment rate. © 2014 Wiley Periodicals, Inc.

  12. Licheniocin 50.2 and Bacteriocins from Lactococcus lactis subsp. lactis biovar. diacetylactis BGBU1-4 Inhibit Biofilms of Coagulase Negative Staphylococci and Listeria monocytogenes Clinical Isolates.

    Science.gov (United States)

    Cirkovic, Ivana; Bozic, Dragana D; Draganic, Veselin; Lozo, Jelena; Beric, Tanja; Kojic, Milan; Arsic, Biljana; Garalejic, Eliana; Djukic, Slobodanka; Stankovic, Slavisa

    2016-01-01

    Coagulase negative staphylococci (CoNS) and Listeria monocytogenes have important roles in pathogenesis of various genital tract infections and fatal foetomaternal infections, respectively. The aim of our study was to investigate the inhibitory effects of two novel bacteriocins on biofilms of CoNS and L. monocytogenes genital isolates. The effects of licheniocin 50.2 from Bacillus licheniformis VPS50.2 and crude extract of bacteriocins produced by Lactococcus lactis subsp. lactis biovar. diacetylactis BGBU1-4 (BGBU1-4 crude extract) were evaluated on biofilm formation and formed biofilms of eight CoNS (four S. epidermidis, two S. hominis, one S. lugdunensis and one S. haemolyticus) and 12 L. monocytogenes genital isolates. Licheniocin 50.2 and BGBU1-4 crude extract inhibited the growth of both CoNS and L. monocytogenes isolates, with MIC values in the range between 200-400 AU/ml for licheniocin 50.2 and 400-3200 AU/ml for BGBU1-4 crude extract. Subinhibitory concentrations (1/2 × and 1/4 × MIC) of licheniocin 50.2 inhibited biofilm formation by all CoNS isolates (p < 0.05, respectively), while BGBU1-4 crude extract inhibited biofilm formation by all L. monocytogenes isolates (p < 0.01 and p < 0.05, respectively). Both bacteriocins in concentrations of 100 AU/mL and 200 AU/mL reduced the amount of 24 h old CoNS and L. monocytogenes biofilms (p < 0.05, p < 0.01, p < 0.001). This study suggests that novel bacteriocins have potential to be used for genital application, to prevent biofilm formation and/or to eradicate formed biofilms, and consequently reduce genital and neonatal infections by CoNS and L. monocytogenes.

  13. Antimicrobial peptide AMPNT-6 from Bacillus subtilis inhibits biofilm formation by Shewanella putrefaciens and disrupts its preformed biofilms on both abiotic and shrimp shell surfaces.

    Science.gov (United States)

    Deng, Qi; Pu, Yuehua; Sun, Lijun; Wang, Yaling; Liu, Yang; Wang, Rundong; Liao, Jianmeng; Xu, Defeng; Liu, Ying; Ye, Riying; Fang, Zhijia; Gooneratne, Ravi

    2017-12-01

    Shewanella putrefaciens biofilm formation is of great concern for the shrimp industry because it adheres easily to food and food-contact surfaces and is a source of persistent and unseen contamination that causes shrimp spoilage and economic losses to the shrimp industry. Different concentrations of an antimicrobial lipopeptide, the fermentation product of Bacillus subtilis, AMPNT-6, were tested for the ability to reduce adhesion and disrupt S. putrefaciens preformed biofilms on two different contact surfaces (shrimp shell, stainless steel sheet). AMPNT-6 displayed a marked dose- and time-dependent anti-adhesive effect>biofilm removal. 3MIC AMPNT-6 was able both to remove biofilm and prevent bacteria from forming biofilm in a 96-well polystyrene microplate used as the model surface. 2MIC AMPNT-6 prevented bacteria from adhering to the microplate surface to form biofilm for 3h and removed already existing biofilm within 24h. Secretion of extracellular polymeric substances incubated in LB broth for 24h by S. putrefaciens was minimal at 3× MIC AMPNT-6. Scanning electron microscopy showed that damage to S. putrefaciens bacteria by AMPNT-6 possibly contributed to the non-adherence to the surfaces. Disruption of the mature biofilm structure by AMPNT-6 contributed to biofilm removal. It is concluded that AMPNT-6 can be used effectively to prevent attachment and also detach S. putrefaciens biofilms from shrimp shells, stainless steel sheets and polystyrene surfaces. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Progress toward understanding the contribution of alkali generation in dental biofilms to inhibition of dental caries

    Science.gov (United States)

    Liu, Ya-Ling; Nascimento, Marcelle; Burne, Robert A

    2012-01-01

    Alkali production by oral bacteria is believed to have a major impact on oral microbial ecology and to be inibitory to the initiation and progression of dental caries. A substantial body of evidence is beginning to accumulate that indicates the modulation of the alkalinogenic potential of dental biofilms may be a promising strategy for caries control. This brief review highlights recent progress toward understanding molecular genetic and physiologic aspects of important alkali-generating pathways in oral bacteria, and the role of alkali production in the ecology of dental biofilms in health and disease. PMID:22996271

  15. Two potential uses for silver nanoparticles coated with Solanum nigrum unripe fruit extract: Biofilm inhibition and photodegradation of dye effluent.

    Science.gov (United States)

    Malaikozhundan, Balasubramanian; Vijayakumar, Sekar; Vaseeharan, Baskaralingam; Jenifer, Anthonisamy Anthoni; Chitra, Ponnaiah; Prabhu, Narayanan Marimuthu; Kannapiran, Ethiraj

    2017-10-01

    Silver nanoparticle was green synthesized involving the unripe fruit extracts of Solanum nigrum (Sn-AgNPs). The synthesized Sn-AgNPs was bio-physically characterized by UV-Vis spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Transmission electron microscopy (TEM). UV-Vis recorded the absorbance spectra at 443 nm. XRD analysis clearly demonstrated the crystalline nature of Sn-AgNPs with Bragg's reflection peaks at 111, 200, 220 and 311 lattice planes. The FTIR spectrum of Sn-AgNPs showed strong bands at 3432, 1555, 1455, 862 and 406 cm -1 which corresponds at O-H, C-H, C-C, C-OH and C-N groups respectively. TEM exhibited the spherical shape of Sn-AgNPs with particle size between 20 and 30 nm. The antibacterial effects of Sn-AgNPs were tested on clinically important biofilm forming Gram positive (Bacillus pumulis and Enterococcus faecalis) and Gram negative (Proteus vulgaris and Vibrio parahaemolyticus) bacteria. The greater inhibition of B. pumulis and E. faecalis was observed at 100 μg mL -1 of Sn-AgNPs compared to P. vulgaris and V. parahaemolyticus. The biofilm inhibition potential of Sn-AgNPs was greater against Gram positive bacteria than that of Gram negative bacteria. Furthermore, Sn-AgNPs effectively degraded the industrial effluent methyl orange dye by photocatalysis. It is concluded that Sn-AgNPs could be used as an effective therapeutics against the biofilm of clinically important bacteria. The green synthesized Sn-AgNPs can be employed to degrade dye effluents and prevent environmental pollution as well. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Bioguided Fractionation Shows Cassia alata Extract to Inhibit Staphylococcus epidermidis and Pseudomonas aeruginosa Growth and Biofilm Formation

    Directory of Open Access Journals (Sweden)

    Samuel Takashi Saito

    2012-01-01

    Full Text Available Plant extracts have a long history to be used in folk medicine. Cassia alata extracts are known to exert antibacterial activity but details on compounds and mechanism of action remain poorly explored. We purified and concentrated the aqueous leaf extract of C. alata by reverse phase-solid phase extraction and screened the resulting CaRP extract for antimicrobial activity. CaRP extract exhibited antimicrobial activity for Pseudomonas aeruginosa, Staphylococcus epidermidis, S. aureus, and Bacillus subtilis. CaRP also inhibited biofilm formation of S. epidermidis and P. aeruginosa. Several bacterial growth-inhibiting compounds were detected when CaRP extract was fractionated by TLC chromatography coupled to bioautography agar overlay technique. HPLC chromatography of CaRP extract yielded 20 subfractions that were tested by bioautography for antimicrobial activity against S. aureus and S. epidermidis. Five bioactive fractions were detected and chemically characterized, using high-resolution mass spectrometry (qTOF-MS/MS. Six compounds from four fractions could be characterized as kaempferol, kaempferol-O-diglucoside, kaempferol-O-glucoside, quercetin-O-glucoside, rhein, and danthron. In the Salmonella/microsome assay CaRP showed weak mutagenicity (MI<3 only in strain TA98, pointing to a frameshift mutation activity. These results indicate that C. alata leaf extract contains a minimum of 7 compounds with antimicrobial activity and that these together or as single substance are active in preventing formation of bacterial biofilm, indicating potential for therapeutic applications.

  17. Bioguided Fractionation Shows Cassia alata Extract to Inhibit Staphylococcus epidermidis and Pseudomonas aeruginosa Growth and Biofilm Formation

    Science.gov (United States)

    Saito, Samuel Takashi; Trentin, Danielle da Silva; Macedo, Alexandre José; Pungartnik, Cristina; Gosmann, Grace; Silveira, Jaqueline de Deos; Guecheva, Temenouga Nikolova; Henriques, João Antonio Pêgas; Brendel, Martin

    2012-01-01

    Plant extracts have a long history to be used in folk medicine. Cassia alata extracts are known to exert antibacterial activity but details on compounds and mechanism of action remain poorly explored. We purified and concentrated the aqueous leaf extract of C. alata by reverse phase-solid phase extraction and screened the resulting CaRP extract for antimicrobial activity. CaRP extract exhibited antimicrobial activity for Pseudomonas aeruginosa, Staphylococcus epidermidis, S. aureus, and Bacillus subtilis. CaRP also inhibited biofilm formation of S. epidermidis and P. aeruginosa. Several bacterial growth-inhibiting compounds were detected when CaRP extract was fractionated by TLC chromatography coupled to bioautography agar overlay technique. HPLC chromatography of CaRP extract yielded 20 subfractions that were tested by bioautography for antimicrobial activity against S. aureus and S. epidermidis. Five bioactive fractions were detected and chemically characterized, using high-resolution mass spectrometry (qTOF-MS/MS). Six compounds from four fractions could be characterized as kaempferol, kaempferol-O-diglucoside, kaempferol-O-glucoside, quercetin-O-glucoside, rhein, and danthron. In the Salmonella/microsome assay CaRP showed weak mutagenicity (MI < 3) only in strain TA98, pointing to a frameshift mutation activity. These results indicate that C. alata leaf extract contains a minimum of 7 compounds with antimicrobial activity and that these together or as single substance are active in preventing formation of bacterial biofilm, indicating potential for therapeutic applications. PMID:22548121

  18. Antibiotic-loaded poly(trimethylene carbonate) degradation, release and staphylococcal biofilm inhibition

    NARCIS (Netherlands)

    Kluin, Otto Samuel

    2016-01-01

    Infections localised to bone (osteomyelitis) rapidly progress to a chronic state in which bacteria form organised communities (biofilms) where they are protected from host defences and antibiotic therapy. Treatment requires surgery followed by systemic and/or local application of antibiotics. With

  19. Chamaecyparis obtusa Essential Oil Inhibits Methicillin-Resistant Staphylococcus aureus Biofilm Formation and Expression of Virulence Factors.

    Science.gov (United States)

    Kim, Eun-Sook; Kang, Sun-Young; Kim, Young-Hoi; Lee, Young-Eun; Choi, Na-Young; You, Yong-Ouk; Kim, Kang-Ju

    2015-07-01

    The emergence of antibiotic-resistant bacteria has caused difficulty in treating infectious diseases. Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most commonly recognized antibiotic-resistant bacteria. Novel antibiotics are urgently required to treat these bacteria. Raw materials derived from natural sources can be used for the development of novel antibiotics, such as Chamaecyparis obtusa (C. obtusa), which has been traditionally used in treating asthmatic disease. In this study, the antibacterial activity of the essential oil (EO) extracted from C. obtusa leaves against MRSA was investigated. MRSA growth and acid production from glucose metabolism were inhibited at concentrations greater than 0.1 mg/mL C. obtusa EO. MRSA biofilm formation was observed using scanning electron microscopy and safranin staining. C. obtusa EO inhibited MRSA biofilm formation at concentrations greater than 0.1 mg/mL. Using real-time polymerase chain reaction, mRNA expression of virulence factor genes, sea, agrA, and sarA, was observed. agrA expression was inhibited with C. obtusa EO concentrations greater than 0.2 mg/mL, whereas inhibition of sea and sarA expression was also observed at a concentration of 0.3 mg/mL. C. obtusa EO was analyzed by gas chromatography (GC) and GC coupled for mass spectrometry, which identified 59 constituents, accounting to 98.99% of the total EO. These findings suggest that C. obtusa EO has antibacterial effects against MRSA, which might be associated with the major components of C. obtusa EO, such as sabinene (19.06%), α-terpinyl acetate (16.99%), bornyl acetate (10.48%), limonene (8.54%), elemol (7.47%), myrcene (5.86%), γ-terpinene (4.04%), and hibaene (3.01%).

  20. Inhibiting mild steel corrosion from sulfate-reducing bacteria using antimicrobial-producing biofilms in Three-Mile-Island process water.

    Science.gov (United States)

    Zuo, R; Ornek, D; Syrett, B C; Green, R M; Hsu, C-H; Mansfeld, F B; Wood, T K

    2004-04-01

    Biofilms were used to produce gramicidin S (a cyclic decapeptide) to inhibit corrosion-causing, sulfate-reducing bacteria (SRB). In laboratory studies these biofilms protected mild steel 1010 continuously from corrosion in the aggressive, cooling service water of the AmerGen Three-Mile-Island (TMI) nuclear plant, which was augmented with reference SRB. The growth of both reference SRB (Gram-positive Desulfosporosinus orientis and Gram-negative Desulfovibrio vulgaris) was shown to be inhibited by supernatants of the gramicidin-S-producing bacteria as well as by purified gramicidin S. Electrochemical impedance spectroscopy and mass loss measurements showed that the protective biofilms decreased the corrosion rate of mild steel by 2- to 10-fold when challenged with the natural SRB of the TMI process water supplemented with D. orientis or D. vulgaris. The relative corrosion inhibition efficiency was 50-90% in continuous reactors, compared to a biofilm control which did not produce the antimicrobial gramicidin S. Scanning electron microscope and reactor images also revealed that SRB attack was thwarted by protective biofilms that secrete gramicidin S. A consortium of beneficial bacteria (GGPST consortium, producing gramicidin S and other antimicrobials) also protected the mild steel.

  1. Melittin and its potential in the destruction and inhibition of the biofilm formation by Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa isolated from bovine milk.

    Science.gov (United States)

    Picoli, Tony; Peter, Cristina Mendes; Zani, João Luíz; Waller, Stefanie Bressan; Lopes, Matheus Gomes; Boesche, Kamilla Neutzling; Vargas, Gilberto D Ávila; Hübner, Silvia de Oliveira; Fischer, Geferson

    2017-11-01

    Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa stand out in veterinary and human medicine for their role in opportunistic infections and their pathogenic mechanisms, including the biofilms formation. It was investigated the antibacterial activity of melittin and antibiofilm of such bacteria. Twelve strains of these microorganisms isolated from bovine milk were used, as well as the strains S. aureus ATCC 12600, E. coli ATCC 8739 and Pseudomonas aeruginosa ATCC 15442. The minimum inhibitory concentrations (MIC) and minimum bactericidal concentration (MBC) were determined by broth microdilution technique. The biofilms were formed in 96-well plates and melittin on these colonies was added at different concentrations and times. Bacteria previously exposed to melittin were evaluated for inhibition of biofilm production. The MIC and MBC were respectively in μg/mL: S. aureus (6-7 and 32-64), E. coli (40-42.5 and 64-128) and P. aeruginosa (65-70 and 64-128). S. aureus biofilms were more sensitive to the action of melittin, since upon exposure to a concentration 10 times lower than the MIC for 4 h, was completely destroyed. In Gram negative bacteria, the pre-formed biofilm was destroyed only when exposed for 4 h under the MIC. With respect to inhibition of biofilm production, S. aureus was the most sensitive again because produced only 37.2% of the biofilm formed by the control (without previous exposure to melittin), when exposed to the MIC, and at a concentration hundred times smaller than MIC, this microorganism produced 75.2% of the biofilm. E. coli was the most resistant bacteria and produced 56.3% of the biofilm, even if previously exposed to melittin MIC. Melittin presents desirable effects in combating microorganisms studied both at your disposal, biofilm destruction and inhibition of the formation, and maybe used in future studies of new strategies to combat infections caused by these pathogens. Copyright © 2017 Elsevier Ltd. All

  2. A tandem Mannich addition–palladium catalyzed ring-closing route toward 4-substituted-3(2H-furanones

    Directory of Open Access Journals (Sweden)

    Jubi John

    2014-06-01

    Full Text Available A facile route towards highly functionalized 3(2H-furanones via a sequential Mannich addition–palladium catalyzed ring closing has been elaborated. The reaction of 4-chloroacetoacetate esters with imines derived from aliphatic and aromatic aldehydes under palladium catalysis afforded 4-substituted furanones in good to excellent yields. 4-Hydrazino-3(2H-furanones could also be synthesized from diazo esters in excellent yields by utilising the developed strategy. We could also efficiently transform the substituted furanones to aza-prostaglandin analogues.

  3. Antibiotic-loaded MoS2 nanosheets to combat bacterial resistance via biofilm inhibition

    Science.gov (United States)

    Zhang, Xu; Zhang, Wentao; Liu, Lizhi; Yang, Mei; Huang, Lunjie; Chen, Kai; Wang, Rong; Yang, Baowei; Zhang, Daohong; Wang, Jianlong

    2017-06-01

    The emergence of antibiotic resistance has resulted in increasing difficulty in treating clinical infections associated with biofilm formation, one of the key processes in turn contributing to enhanced antibiotic resistance. With the rapid development of nanotechnology, a new way to overcome antibiotic resistance has opened up. Based on the many and diverse properties of MoS2 nanosheets that have attracted wide attention, in particular their antibacterial potential, herein, a novel antimicrobial agent to combat resistant gram-positive Staphylococcus aureus and gram-negative Salmonella was prepared using chitosan functionalized MoS2 nanosheets loading tetracycline hydrochloride drugs (abbreviated to CM-TH). The antibacterial and anti-biofilm activities of the CM-TH nanocomposites showed the synergetic effect that the combination of nanomaterials and antibiotics was more efficient than either working alone. In particularly, the minimum inhibitory concentration values generally decreased by a factor of dozens, suggesting that CM-TH may become a possible alternative to traditional antibiotics in disrupting biofilms and overcoming antibiotic resistance in treating medical diseases.

  4. Scaffold of Selenium Nanovectors and Honey Phytochemicals for Inhibition of Pseudomonas aeruginosa Quorum Sensing and Biofilm Formation

    Directory of Open Access Journals (Sweden)

    Prateeksha

    2017-03-01

    Full Text Available Honey is an excellent source of polyphenolic compounds that are effective in attenuating quorum sensing (QS, a chemical process of cell-to-cell communication system used by the opportunistic pathogen Pseudomonas aeruginosa to regulate virulence and biofilm formation. However, lower water solubility and inadequate bioavailability remains major concerns of these therapeutic polyphenols. Its therapeutic index can be improved by using nano-carrier systems to target QS signaling potently. In the present study, we fabricated a unique drug delivery system comprising selenium nanoparticles (SeNPs; non-viral vectors and polyphenols of honey (HP for enhancement of anti-QS activity of HP against P. aeruginosa PAO1. The developed selenium nano-scaffold showed superior anti-QS activity, anti-biofilm efficacy, and anti-virulence potential in both in-vitro and in-vivo over its individual components, SeNPs and HP. LasR is inhibited by selenium nano-scaffold in-vitro. Using computational molecular docking studies, we have also demonstrated that the anti-virulence activity of selenium nano-scaffold is reliant on molecular binding that occurs between HP and the QS receptor LasR through hydrogen bonding and hydrophobic interactions. Our preliminary investigations with selenium-based nano-carriers hold significant promise to improve anti-virulence effectiveness of phytochemicals by enhancing effective intracellular delivery.

  5. Inhibition of growth and biofilm formation of clinical bacterial isolates by NiO nanoparticles synthesized from Eucalyptus globulus plants.

    Science.gov (United States)

    Saleem, Samia; Ahmed, Bilal; Khan, Mohammad Saghir; Al-Shaeri, Majed; Musarrat, Javed

    2017-10-01

    Nanotechnology based therapeutics has emerged as a promising approach for augmenting the activity of existing antimicrobials due to the unique physical and chemical properties of nanoparticles (NPs). Nickel oxide nanoparticles (NiO-NPs) have been suggested as prospective antibacterial and antitumor agent. In this study, NiO-NPs have been synthesized by a green approach using Eucalyptus globulus leaf extract and assessed for their bactericidal activity. The morphology and purity of synthesized NiO-NPs determined through various spectroscopic techniques like UV-Visible, FT-IR, XRD, EDX and electron microscopy differed considerably. The synthesized NiO-NPs were pleomorphic varying in size between 10 and 20 nm. The XRD analysis revealed the average size of NiO-NPs as 19 nm. The UV-Vis spectroscopic data showed a strong SPR of NiO-NPs with a characteristic spectral peak at 396 nm. The FTIR data revealed various functional moieties like C=C, C-N, C-H and O-H which elucidate the role of leaf biomolecules in capping and dispersal of NiO-NPs. The bioactivity assay revealed the antibacterial and anti-biofilm activity of NiO-NPs against ESβL (+) E. coli, P. aeruginosa, methicillin sensitive and resistant S. aureus. Growth inhibition assay demonstrated time and NiO-NPs concentration dependent decrease in the viability of treated cells. NiO-NPs induced biofilm inhibition was revealed by a sharp increase in characteristic red fluorescence of PI, while SEM images of NiO-NPs treated cells were irregular shrink and distorted with obvious depressions/indentations. The results suggested significant antibacterial and antibiofilm activity of NiO-NPs which may play an important role in the management of infectious diseases affecting human health. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Inactivation of Cronobacter malonaticus cells and inhibition of its biofilm formation exposed to hydrogen peroxide stress.

    Science.gov (United States)

    Ye, Yingwang; Zhang, Maofeng; Jiao, Rui; Ling, Na; Zhang, Xiyan; Tong, Liaowang; Zeng, Haiyang; Zhang, Jumei; Wu, Qingping

    2018-01-01

    Presence of Cronobacter malonaticus in powdered infant formula (PIF) poses a high risk to infant and public health. Cronobacter malonaticus has been widely distributed in food and food processing environments, and the true origin of C. malonaticus in PIF is poorly understood. Control and prevention of C. malonaticus is necessary for achieving microbial safety of PIF. However, little information about decontamination of C. malonaticus is available. In this study, effects of hydrogen peroxide on inactivation and morphological changes of C. malonaticus cells were determined. Furthermore, inhibitory effects of H 2 O 2 on biofilm formation in C. malonaticus were also performed. Results indicated that H 2 O 2 could completely inactivate C. malonaticus in sterile water with 0.06% H 2 O 2 for 25 min, 0.08% H 2 O 2 for 15 min, and 0.10% for 10 min, respectively, whereas the survival rates of C. malonaticus in tryptic soy broth medium significantly increased with the same treatment time and concentration of H 2 O 2 . In addition, morphological changes of C. malonaticus cells, including cell shrinkage, disruption of cells, cell intercession, and leakage of intercellular material in sterile water after H 2 O 2 treatment, were more predominant than those in tryptic soy broth. Finally, significant reduction in biofilm formation by H 2 O 2 was found using crystal violet staining, scanning electron microscopy, and confocal laser scanning microscopy detection compared with control samples. This is the first report to determine the effects of H 2 O 2 on C. malonaticus cells and biofilm formation. The findings provided valuable information for practical application of H 2 O 2 for decontamination of C. malonaticus in dairy processing. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  7. D-Tagatose inhibits the growth and biofilm formation of Streptococcus mutans

    OpenAIRE

    Hasibul, Khaleque; Nakayama-Imaohji, Haruyuki; Hashimoto, Masahito; Yamasaki, Hisashi; Ogawa, Takaaki; Waki, Junpei; Tada, Ayano; Yoneda, Saori; Tokuda, Masaaki; Miyake, Minoru; Kuwahara, Tomomi

    2017-01-01

    Dental caries is an important global health concern and Streptococcus mutans has been established as a major cariogenic bacterial species. Reports indicate that a rare sugar, D-tagatose, is not easily catabolized by pathogenic bacteria. In the present study, the inhibitory effects of D-tagatose on the growth and biofilm formation of S. mutans GS-5 were examined. Monitoring S. mutans growth over a 24 h period revealed that D-tagatose prolonged the lag phase without interfering with the final c...

  8. Combinatorial effects of aromatic 1,3 – disubstituted ureas and fluoride on in vitro inhibition of Streptococcus mutans biofilm formation

    Directory of Open Access Journals (Sweden)

    Gurmeet eKaur

    2016-06-01

    Full Text Available Dental caries occurs as a result of disequilibrium between acid producing pathogenic bacteria and alkali generating commensal bacteria within a dental biofilm (dental plaque. S. mutans has been reported as a primary cariogenic pathogen associated with dental caries. Emergence of multidrug resistant as well as fluoride resistant strains of Streptococcus mutans due to over usage of various antibiotics is a rising problem and prompted the researchers worldwide to search for alternative therapies. In this perspective, the present study was aimed to screen selective inhibitors against ComA, a bacteriocin associated ABC transporter, involved in the quorum sensing of S. mutans. In light of our previous in silico findings, 1,3- disubstituted urea derivatives which had better affinity to ComA were chemically synthesized in the present study for in vitro evaluation of S. mutans biofilm inhibition. The results revealed that 1,3- disubstituted urea derivatives showed good biofilm inhibition. In addition, the synthesized compounds exhibited potent synergy with a very low concentration of fluoride (31.25 ppm to 62.5 ppm in inhibiting the biofilm formation of S. mutans without affecting the bacterial growth. Further, the results were confirmed by confocal laser scanning microscopy. On the whole, from our experimental results we conclude that the combinatorial application of fluoride and disubstituted ureas has a potential synergistic effect which has a promising approach in combating multidrug resistant and fluoride resistant S. mutans in dental caries management.

  9. The natural antimicrobial carvacrol inhibits quorum sensing in Chromobacterium violaceum and reduces bacterial biofilm formation at sub-lethal concentrations

    NARCIS (Netherlands)

    Burt, Sara A|info:eu-repo/dai/nl/140114432; Ojo-Fakunle, Victoria T A; Woertman, Jenifer; Veldhuizen, Edwin J A|info:eu-repo/dai/nl/19545264X

    2014-01-01

    The formation of biofilm by bacteria confers resistance to biocides and presents problems in medical and veterinary clinical settings. Here we report the effect of carvacrol, one of the major antimicrobial components of oregano oil, on the formation of biofilms and its activity on existing biofilms.

  10. Positively charged biopolymeric nanoparticles for the inhibition of Pseudomonas aeruginosa biofilms

    Energy Technology Data Exchange (ETDEWEB)

    Chronopoulou, Laura [University of Rome La Sapienza, Department of Chemistry (Italy); Di Domenico, Enea Gino [IRCCS, Department of Clinical Pathology and Microbiology, San Gallicano Institute (Italy); Ascenzioni, Fiorentina [University of Rome La Sapienza, Department of Biology and Biotechnology C. Darwin (Italy); Palocci, Cleofe, E-mail: cleofe.palocci@uniroma1.it [University of Rome La Sapienza, Department of Chemistry (Italy)

    2016-10-15

    Currently, many microbial infections have the potential to become lethal owing to the development of antimicrobial resistance by means of different mechanisms and mainly on the basis of the fact that many drugs are unable to reach therapeutic levels in the target sites. This requires the use of high doses and frequent administrations, causing adverse side effects or in some cases toxicity. The use of nanoparticle systems could help overcome such problems and increase drug efficacy. In the present study, we developed a new drug delivery system based on the use of biopolymeric nanovectors loaded with tobramycin (Tb), which is the standard antibiotic for the treatment of Cystic Fibrosis-associated P. aeruginosa lung infections. Tb-loaded biopolymeric nanoparticles composed by dextran sulfate (DS) and chitosan (CS) were prepared by ionotropic gelation. We optimized drug entrapment in DS/CS nanoparticles, obtaining particles of 170 nm and with a drug loading of 400 µg Tb/mg of nanoparticles. In accord with in vitro release experiments, such preparations were able to release approximately 25 % of their cargo in 60 h. In vitro, the antimicrobial efficacy of the drug delivery system on P. aeruginosa biofilm was tested and compared to the effects of free drug revealing that this formulation can reduce the viability of P. aeruginosa biofilms for 48 h with a single-dose administration.

  11. Positively charged biopolymeric nanoparticles for the inhibition of Pseudomonas aeruginosa biofilms

    International Nuclear Information System (INIS)

    Chronopoulou, Laura; Di Domenico, Enea Gino; Ascenzioni, Fiorentina; Palocci, Cleofe

    2016-01-01

    Currently, many microbial infections have the potential to become lethal owing to the development of antimicrobial resistance by means of different mechanisms and mainly on the basis of the fact that many drugs are unable to reach therapeutic levels in the target sites. This requires the use of high doses and frequent administrations, causing adverse side effects or in some cases toxicity. The use of nanoparticle systems could help overcome such problems and increase drug efficacy. In the present study, we developed a new drug delivery system based on the use of biopolymeric nanovectors loaded with tobramycin (Tb), which is the standard antibiotic for the treatment of Cystic Fibrosis-associated P. aeruginosa lung infections. Tb-loaded biopolymeric nanoparticles composed by dextran sulfate (DS) and chitosan (CS) were prepared by ionotropic gelation. We optimized drug entrapment in DS/CS nanoparticles, obtaining particles of 170 nm and with a drug loading of 400 µg Tb/mg of nanoparticles. In accord with in vitro release experiments, such preparations were able to release approximately 25 % of their cargo in 60 h. In vitro, the antimicrobial efficacy of the drug delivery system on P. aeruginosa biofilm was tested and compared to the effects of free drug revealing that this formulation can reduce the viability of P. aeruginosa biofilms for 48 h with a single-dose administration.

  12. Positively charged biopolymeric nanoparticles for the inhibition of Pseudomonas aeruginosa biofilms

    Science.gov (United States)

    Chronopoulou, Laura; Di Domenico, Enea Gino; Ascenzioni, Fiorentina; Palocci, Cleofe

    2016-10-01

    Currently, many microbial infections have the potential to become lethal owing to the development of antimicrobial resistance by means of different mechanisms and mainly on the basis of the fact that many drugs are unable to reach therapeutic levels in the target sites. This requires the use of high doses and frequent administrations, causing adverse side effects or in some cases toxicity. The use of nanoparticle systems could help overcome such problems and increase drug efficacy. In the present study, we developed a new drug delivery system based on the use of biopolymeric nanovectors loaded with tobramycin (Tb), which is the standard antibiotic for the treatment of Cystic Fibrosis-associated P. aeruginosa lung infections. Tb-loaded biopolymeric nanoparticles composed by dextran sulfate (DS) and chitosan (CS) were prepared by ionotropic gelation. We optimized drug entrapment in DS/CS nanoparticles, obtaining particles of 170 nm and with a drug loading of 400 µg Tb/mg of nanoparticles. In accord with in vitro release experiments, such preparations were able to release approximately 25 % of their cargo in 60 h. In vitro, the antimicrobial efficacy of the drug delivery system on P. aeruginosa biofilm was tested and compared to the effects of free drug revealing that this formulation can reduce the viability of P. aeruginosa biofilms for 48 h with a single-dose administration.

  13. Comparative Proteomic Analysis Provides insight into the Key Proteins as Possible Targets Involved in Aspirin Inhibiting Biofilm Formation of Staphylococcus xylosus

    Directory of Open Access Journals (Sweden)

    Chang-Geng Xu

    2017-08-01

    Full Text Available Staphylococcus xylosus is an opportunistic pathogen that causes infection in humans and cow mastitis. And S. xylosus possesses a strong ability to form biofilms in vitro. As biofilm formation facilitates resistance to antimicrobial agents, the discovery of new medicinal properties for classic drugs is highly desired. Aspirin, which is the most common active component of non-steroidal anti-inflammatory compounds, affects the biofilm-forming capacity of various bacterial species. We have found that aspirin effectively inhibits biofilm formation of S. xylosus by Crystal violet (CV staining and scanning electron microscopy analyses. The present study sought to elucidate possible targets of aspirin in suppressing S. xylosus biofilm formation. Based on an isobaric tag for relative and absolute quantitation (iTRAQ fold-change of >1.2 or <0.8 (P-value < 0.05, 178 differentially expressed proteins, 111 down-regulated and 67 up-regulated, were identified after application of aspirin to cells at a 1/2 minimal inhibitory concentration. Gene ontology analysis indicated enrichment in metabolic processes for the majority of the differentially expressed proteins. We then used the Kyoto Encyclopedia of Genes and Genomes (KEGG pathway database to analyze a large number of differentially expressed proteins and identified genes involved in biosynthesis of amino acids pathway, carbon metabolism (pentose phosphate and glycolytic pathways, tricarboxylic acid cycle and nitrogen metabolism (histidine metabolism. These novel proteins represent candidate targets in aspirin-mediated inhibition of S. xylosus biofilm formation at sub-MIC levels. The findings lay the foundation for further studies to identify potential aspirin targets.

  14. Quercetin Assists Fluconazole to Inhibit Biofilm Formations of Fluconazole-Resistant Candida Albicans in In Vitro and In Vivo Antifungal Managements of Vulvovaginal Candidiasis

    Directory of Open Access Journals (Sweden)

    Mei Gao

    2016-11-01

    Full Text Available Background: Vulvovaginal candidiasis (VVC is a common gynecological disease. Candida albicans is believed to be mainly implicated in VVC occurrence, the biofilm of which is one of the virulence factors responsible for resistance to traditional antifungal agents especially to fluconazole (FCZ. Quercetin (QCT is a dietary flavonoid and has been demonstrated to be antifungal against C. albicans biofilm. Methods: 17 C. albicans isolates including 15 clinical ones isolated from VVC patients were employed to investigate the effects of QCT and/or FCZ on the inhibition of C. albicans biofilm. Results: We observed that 64 µg/mL QCT and/or 128 µg/mL FCZ could (i be synergistic against 10 FCZ-resistant planktonic and 17 biofilm cells of C. albicans, (ii inhibit fungal adherence, cell surface hydrophobicity (CSH, flocculation, yeast-to-hypha transition, metabolism, thickness and dispersion of biofilms; (iii down-regulate the expressions of ALS1, ALS3, HWP1, SUN41, UME6 and ECE1 and up-regulate the expressions of PDE2, NRG1 and HSP90, and we also found that (iv the fungal burden was reduced in vaginal mucosa and the symptoms were alleviated in a murine VVC model after the treatments of 5 mg/kg QCT and/or 20 mg/kg FCZ. Conclusion: Together with these results, it could be demonstrated that QCT could be a favorable antifungal agent and a promising synergist with FCZ in the clinical management of VVC caused by C. albicans biofilm.

  15. Natural 4-hydroxy-2,5-dimethyl-3(2H)-furanone (Furaneol®).

    Science.gov (United States)

    Schwab, Wilfried

    2013-06-13

    4-Hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF, furaneol®) and its methyl ether 2,5-dimethyl-4-methoxy-3(2H)-furanone (DMMF) are import aroma chemicals and are considered key flavor compounds in many fruit. Due to their attractive sensory properties they are highly appreciated by the food industry. In fruits 2,5-dimethyl-3(2H)-furanones are synthesized by a series of enzymatic steps whereas HDMF is also a product of the Maillard reaction. Numerous methods for the synthetic preparation of these compounds have been published and are applied by industry, but for the development of a biotechnological process the knowledge and availability of biosynthetic enzymes are required. During the last years substantial progress has been made in the elucidation of the biological pathway leading to HDMF and DMMF. This review summarizes the latest advances in this field.

  16. Natural 4-Hydroxy-2,5-dimethyl-3(2H-furanone (Furaneol®

    Directory of Open Access Journals (Sweden)

    Wilfried Schwab

    2013-06-01

    Full Text Available 4-Hydroxy-2,5-dimethyl-3(2H-furanone (HDMF, furaneol® and its methyl ether 2,5-dimethyl-4-methoxy-3(2H-furanone (DMMF are import aroma chemicals and are considered key flavor compounds in many fruit. Due to their attractive sensory properties they are highly appreciated by the food industry. In fruits 2,5-dimethyl-3(2H-furanones are synthesized by a series of enzymatic steps whereas HDMF is also a product of the Maillard reaction. Numerous methods for the synthetic preparation of these compounds have been published and are applied by industry, but for the development of a biotechnological process the knowledge and availability of biosynthetic enzymes are required. During the last years substantial progress has been made in the elucidation of the biological pathway leading to HDMF and DMMF. This review summarizes the latest advances in this field.

  17. Awa1p on the cell surface of sake yeast inhibits biofilm formation and the co-aggregation between sake yeasts and Lactobacillus plantarum ML11-11.

    Science.gov (United States)

    Hirayama, Satoru; Shimizu, Masashi; Tsuchiya, Noriko; Furukawa, Soichi; Watanabe, Daisuke; Shimoi, Hitoshi; Takagi, Hiroshi; Ogihara, Hirokazu; Morinaga, Yasushi

    2015-05-01

    We examined mixed-species biofilm formation between Lactobacillus plantarum ML11-11 and both foaming and non-foaming mutant strains of Saccharomyces cerevisiae sake yeasts. Wild-type strains showed significantly lower levels of biofilm formation compared with the non-foaming mutants. Awa1p, a protein involved in foam formation during sake brewing, is a glycosylphosphatidylinositol (GPI)-anchored protein and is associated with the cell wall of sake yeasts. The AWA1 gene of the non-foaming mutant strain Kyokai no. 701 (K701) has lost the C-terminal sequence that includes the GPI anchor signal. Mixed-species biofilm formation and co-aggregation of wild-type strain Kyokai no. 7 (K7) were significantly lower than K701 UT-1 (K701 ura3/ura3 trp1/trp1), while the levels of strain K701 UT-1 carrying the AWA1 on a plasmid were comparable to those of K7. The levels of biofilm formation and co-aggregation of the strain K701 UT-1 harboring AWA1 with a deleted GPI anchor signal were similar to those of K701 UT-1. These results clearly demonstrate that Awa1p present on the surface of sake yeast strain K7 inhibits adhesion between yeast cells and L. plantarum ML11-11, consequently impeding mixed-species biofilm formation. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  18. Mechanisms of inhibition by fluoride of urease activities of cell suspensions and biofilms of Staphylococcus epidermidis, Streptococcus salivarius, Actinomyces naeslundii and of dental plaque.

    Science.gov (United States)

    Barboza-Silva, E; Castro, A C D; Marquis, R E

    2005-12-01

    Fluoride is known to be a potent inhibitor of bacterial ureases and can also act in the form of hydrofluoric acid as a transmembrane proton conductor to acidify the cytoplasm of intact cells with possible indirect, acid inhibition of urease. Our research objectives were to assess the inhibitory potencies of fluoride for three urease-positive bacteria commonly found in the mouth and to determine the relative importance of direct and indirect inhibition of ureases for overall inhibition of intact cells or biofilms. The experimental design involved intact bacteria in suspensions, mono-organism biofilms, cell extracts, and dental plaque. Standard enzymatic assays for ammonia production from urea were used. We found that ureolysis by cells in suspensions or mono-organism biofilms of Staphylococcus epidermidis, Streptococcus salivarius or Actinomyces naeslundii was inhibited by fluoride at plaque levels of 0.1-0.5 mm in a pH-dependent manner. The results of experiments with the organic weak acids indomethacin and capric acid, which do not directly inhibit urease enzyme, indicated that weak-acid effects leading to cytoplasmic acidification are also involved in fluoride inhibition. However, direct fluoride inhibition of urease appeared to be the major mechanism for reduction in ureolytic activity in acid environments. Results of experiments with freshly harvested supragingival dental plaque indicated responses to fluoride similar to those of S. salivarius with pH-dependent fluoride inhibition and both direct and indirect inhibition of urease. Fluoride can act to diminish alkali production from urea by oral bacteria through direct and indirect mechanisms.

  19. Streptococcus oligofermentans inhibits Streptococcus mutans in biofilms at both neutral pH and cariogenic conditions

    NARCIS (Netherlands)

    Bao, X.; de Soet, J.J.; Tong, H.; Gao, X.; He, L.; van Loveren, C.; Deng, D.M.

    2015-01-01

    Homeostasis of oral microbiota can be maintained through microbial interactions. Previous studies showed that Streptococcus oligofermentans, a non-mutans streptococci frequently isolated from caries-free subjects, inhibited the cariogenic Streptococcus mutans by the production of hydrogen peroxide

  20. CATALYTIC KINETIC RESOLUTION OF 5-ALKOXY-2(5H)-FURANONES

    NARCIS (Netherlands)

    FABER, WS; Kok, Johan C; DELANGE, B; FERINGA, BL; Faber, Wijnand S.; Lange, Ben de; Feringa, Bernard

    1994-01-01

    The kinetic resolution of racemic 5-alkoxy-2(5H)-furanones, using a chiral aminoalcohol catalyzed 1-4-addition of arylthiols, was examined. Using various butenolides it was shown that a gamma-alkoxy substituent appears to be essential to reach high enantioselectivities whereas electron-donating

  1. Inhibition of uropathogenic biofilm growth on silicone rubber in human urine by lactobacilli - a teleologic approach

    NARCIS (Netherlands)

    Velraeds, MMC; van de Belt-Gritter, B; Busscher, HJ; Reid, G; van der Mei, HC

    2000-01-01

    The ability of three Lactobacillus strains to inhibit the adhesion and growth of naturally occurring uropathogens on silicone rubber was investigated in human urine. The importance of biosurfactant production by Lactobacillus in discouraging uropathogen growth was determined in relation to the

  2. Serrulatane Diterpenoid from Eremophila neglecta Exhibits Bacterial Biofilm Dispersion and Inhibits Release of Pro-inflammatory Cytokines from Activated Macrophages.

    Science.gov (United States)

    Mon, Htwe H; Christo, Susan N; Ndi, Chi P; Jasieniak, Marek; Rickard, Heather; Hayball, John D; Griesser, Hans J; Semple, Susan J

    2015-12-24

    The purpose of this study was to assess the biofilm-removing efficacy and inflammatory activity of a serrulatane diterpenoid, 8-hydroxyserrulat-14-en-19-oic acid (1), isolated from the Australian medicinal plant Eremophila neglecta. Biofilm breakup activity of compound 1 on established Staphylococcus epidermidis and Staphylococcus aureus biofilms was compared to the antiseptic chlorhexidine and antibiotic levofloxacin. In a time-course study, 1 was deposited onto polypropylene mesh to mimic a wound dressing and tested for biofilm removal. The ex-vivo cytotoxicity and effect on lipopolysaccharide-induced pro-inflammatory cytokine release were studied in mouse primary bone-marrow-derived macrophage (BMDM) cells. Compound 1 was effective in dispersing 12 h pre-established biofilms with a 7 log10 reduction of viable bacterial cell counts, but was less active against 24 h biofilms (approximately 2 log10 reduction). Compound-loaded mesh showed dosage-dependent biofilm-removing capability. In addition, compound 1 displayed a significant inhibitory effect on tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) secretion from BMDM cells, but interleukin-1 beta (IL-1β) secretion was not significant. The compound was not cytotoxic to BMDM cells at concentrations effective in removing biofilm and lowering cytokine release. These findings highlight the potential of this serrulatane diterpenoid to be further developed for applications in wound management.

  3. Modification of Titanium Substrates with Chimeric Peptides Comprising Antimicrobial and Titanium-Binding Motifs Connected by Linkers To Inhibit Biofilm Formation.

    Science.gov (United States)

    Liu, Zihao; Ma, Shiqing; Duan, Shun; Xuliang, Deng; Sun, Yingchun; Zhang, Xi; Xu, Xinhua; Guan, Binbin; Wang, Chao; Hu, Meilin; Qi, Xingying; Zhang, Xu; Gao, Ping

    2016-03-02

    Bacterial adhesion and biofilm formation are the primary causes of implant-associated infection, which is difficult to eliminate and may induce failure in dental implants. Chimeric peptides with both binding and antimicrobial motifs may provide a promising alternative to inhibit biofilm formation on titanium surfaces. In this study, chimeric peptides were designed by connecting an antimicrobial motif (JH8194: KRLFRRWQWRMKKY) with a binding motif (minTBP-1: RKLPDA) directly or via flexible/rigid linkers to modify Ti surfaces. We evaluated the binding behavior of peptides using quartz crystal microbalance (QCM) and atomic force microscopy (AFM) techniques and investigated the effect of the modification of titanium surfaces with these peptides on the bioactivity of Streptococcus gordonii (S. gordonii) and Streptococcus sanguis (S. sanguis). Compared with the flexible linker (GGGGS), the rigid linker (PAPAP) significantly increased the adsorption of the chimeric peptide on titanium surfaces (p chimeric peptide with the rigid linker exhibited more effective antimicrobial ability than the peptide with the flexible linker. This finding was ascribed to the ability of the rigid linker to separate functional domains and reduce their interference to the maximum extent. Consequently, the performance of chimeric peptides with specific titanium-binding motifs and antimicrobial motifs against bacteria can be optimized by the proper selection of linkers. This rational design of chimeric peptides provides a promising alternative to inhibit the formation of biofilms on titanium surfaces with the potential to prevent peri-implantitis and peri-implant mucositis.

  4. Prooxidant action of furanone compounds: implication of reactive oxygen species in the metal-dependent strand breaks and the formation of 8-hydroxy-2'-deoxyguanosine in DNA.

    Science.gov (United States)

    Murakami, K; Haneda, M; Makino, T; Yoshino, M

    2007-07-01

    Prooxidant properties of furanone compounds including 2,5-furanone (furaneol, 4-hydroxy-2,5-dimethyl-furan-3-one), 4,5-furanone (4,5-dimethyl-3-hydroxy-2(5H)-furanone) (sotolone) and cyclotene (2-hydroxy-3-methyl-2-cyclopenten-1-one) were analyzed in relation to the metal-reducing activity. Only 2.5-furanone known as a "strawberry or pineapple furanone" inactivated aconitase the most sensitive enzyme to active oxygen in the presence of ferrous sulfate, suggesting the furaneol/iron-mediated generation of reactive oxygen species. 2,5-Furanone caused strand scission of pBR322 DNA in the presence of copper. Treatment of calf thymus DNA with 2,5-furanone plus copper produced 8-hydroxy-2'-deoxyguanosine in DNA. 2,5-Furanone showed a potent copper-reducing activity, and thus, DNA strand breaks and the formation of 8-hydroxy-2'-deoxyguanosine by 2,5-furanone can be initiated by the production of superoxide radical through the reduction of cupric ion to cuprous ion, resulting in the conversion to hydrogen peroxide and hydroxyl radical. However, an isomer and analog of 2,5-furanone, 4,5-furanone and cyclotene, respectively, did not show an inactivation of aconitase, DNA injuries including strand breakage and the formation of 8-hydroxy-2'-deoxyguanosine, and copper-reducing activity. Cytotoxic effect of 2,5-furanone with hydroxyketone structure can be explained by its prooxidant properties: furaneol/transition metal complex generates reactive oxygen species causing the inactivation of aconitase and the formation of DNA base damage by hydroxyl radical.

  5. Baicalin inhibits biofilm formation, attenuates the quorum sensing-controlled virulence and enhances Pseudomonas aeruginosa clearance in a mouse peritoneal implant infection model.

    Directory of Open Access Journals (Sweden)

    Jing Luo

    Full Text Available The quorum sensing (QS circuit plays a role in the precise regulation of genes controlling virulence factors and biofilm formation in Pseudomonas aeruginosa. QS-controlled biofilm formation by Pseudomonas aeruginosa in clinical settings has remained controversial due to emerging drug resistance; therefore, screening diverse compounds for anti-biofilm or anti-QS activities is important. This study demonstrates the ability of sub-minimum inhibitory concentrations (sub-MICs of baicalin, an active natural compound extracted from the traditional Chinese medicinal Scutellaria baicalensis, to inhibit the formation of Pseudomonas aeruginosa biofilms and enhance the bactericidal effects of various conventional antibiotics in vitro. In addition, baicalin exerted dose-dependent inhibitory effects on virulence phenotypes (LasA protease, LasB elastase, pyocyanin, rhamnolipid, motilities and exotoxin A regulated by QS in Pseudomonas aeruginosa. Moreover, the expression levels of QS-regulatory genes, including lasI, lasR, rhlI, rhlR, pqsR and pqsA, were repressed after sub-MIC baicalin treatment, resulting in significant decreases in the QS signaling molecules 3-oxo-C12-HSL and C4-HSL, confirming the ability of baicalin-mediated QS inhibition to alter gene and protein expression. In vivo experiments indicated that baicalin treatment reduces Pseudomonas aeruginosa pathogenicity in Caenorhabditis elegans. Greater worm survival in the baicalin-treated group manifested as an increase in the LT50 from 24 to 96 h. In a mouse peritoneal implant infection model, baicalin treatment enhanced the clearance of Pseudomonas aeruginosa from the implants of mice infected with Pseudomonas aeruginosa compared with the control group. Moreover, the combination of baicalin and antibiotics significantly reduced the numbers of colony-forming units in the implants to a significantly greater degree than antibiotic treatment alone. Pathological and histological analyses revealed

  6. Bacterial self-defense antibiotics release from organic-inorganic hybrid multilayer films for long-term anti-adhesion and biofilm inhibition properties.

    Science.gov (United States)

    Xu, Qingwen; Li, Xi; Jin, Yingying; Sun, Lin; Ding, Xiaoxu; Liang, Lin; Wang, Lei; Nan, Kaihui; Ji, Jian; Chen, Hao; Wang, Bailiang

    2017-12-14

    Implant-associated bacterial infections pose serious medical and financial issues due to the colonization and proliferation of pathogens on the surface of the implant. The as-prepared traditional antibacterial surfaces can neither resist bacterial adhesion nor inhibit the development of biofilm over the long term. Herein, novel (montmorillonite/poly-l-lysine-gentamicin sulfate) 8 ((MMT/PLL-GS) 8 ) organic-inorganic hybrid multilayer films were developed to combine enzymatic degradation PLL for on-demand self-defense antibiotics release. Small molecule GS was loaded into the multilayer films during self-assembly and the multilayer films showed pH-dependent and linear growth behavior. The chymotrypsin- (CMS) and bacterial infections-responsive film degradation led to the peeling of the films and GS release. Enzyme-responsive GS release exhibited CMS concentration dependence as measured by the size of the inhibition zone and SEM images. Notably, the obtained antibacterial films showed highly efficient bactericidal activity which killed more than 99.9% of S. aureus in 12 h. Even after 3 d of incubation in S. aureus, E. coli or S. epidermidis solutions, the multilayer films exhibited inhibition zones of more than 1.5 mm in size. Both in vitro and in vivo antibacterial tests indicated good cell compatibility, and anti-inflammatory, and long-term bacterial anti-adhesion and biofilm inhibition properties.

  7. Microflow photochemistry: UVC-induced [2 + 2]-photoadditions to furanone in a microcapillary reactor

    Directory of Open Access Journals (Sweden)

    Sylvestre Bachollet

    2013-10-01

    Full Text Available [2 + 2]-Cycloadditions of cyclopentene and 2,3-dimethylbut-2-ene to furanone were investigated under continuous-flow conditions. Irradiations were conducted in a FEP-microcapillary module which was placed in a Rayonet chamber photoreactor equipped with low wattage UVC-lamps. Conversion rates and isolated yields were compared to analogue batch reactions in a quartz test tube. In all cases examined, the microcapillary reactor furnished faster conversions and improved product qualities.

  8. CATALYTIC KINETIC RESOLUTION OF 5-ALKOXY-2(5H)-FURANONES

    OpenAIRE

    FABER, WS; Kok, Johan C; DELANGE, B; FERINGA, BL; Faber, Wijnand S.; Lange, Ben de; Feringa, Bernard

    1994-01-01

    The kinetic resolution of racemic 5-alkoxy-2(5H)-furanones, using a chiral aminoalcohol catalyzed 1-4-addition of arylthiols, was examined. Using various butenolides it was shown that a gamma-alkoxy substituent appears to be essential to reach high enantioselectivities whereas electron-donating substituents in the arylthiols also increase the selectivity. Cinchona alkaloids are the preferred catalysts for the kinetic resolution, with quinine and quinidine leading to the most efficient and sel...

  9. Multitask Imidazolium Salt Additives for Innovative Poly(l-lactide) Biomaterials: Morphology Control, Candida spp. Biofilm Inhibition, Human Mesenchymal Stem Cell Biocompatibility, and Skin Tolerance.

    Science.gov (United States)

    Schrekker, Clarissa M L; Sokolovicz, Yuri C A; Raucci, Maria G; Selukar, Balaji S; Klitzke, Joice S; Lopes, William; Leal, Claudio A M; de Souza, Igor O P; Galland, Griselda B; Dos Santos, João Henrique Z; Mauler, Raquel S; Kol, Moshe; Dagorne, Samuel; Ambrosio, Luigi; Teixeira, Mário L; Morais, Jonder; Landers, Richard; Fuentefria, Alexandre M; Schrekker, Henri S

    2016-08-24

    Candida species have great ability to colonize and form biofilms on medical devices, causing infections in human hosts. In this study, poly(l-lactide) films with different imidazolium salt (1-n-hexadecyl-3-methylimidazolium chloride (C16MImCl) and 1-n-hexadecyl-3-methylimidazolium methanesulfonate (C16MImMeS)) contents were prepared, using the solvent casting process. Poly(l-lactide)-imidazolium salt films were obtained with different surface morphologies (spherical and directional), and the presence of the imidazolium salt in the surface was confirmed. These films with different concentrations of the imidazolium salts C16MImCl and C16MImMeS presented antibiofilm activity against isolates of Candida tropicalis, Candida parapsilosis, and Candida albicans. The minor antibiofilm concentration assay enabled one to determine that an increasing imidazolium salt content promoted, in general, an increase in the inhibition percentage of biofilm formation. Scanning electron microscopy micrographs confirmed the effective prevention of biofilm formation on the imidazolium salt containing biomaterials. Lower concentrations of the imidazolium salts showed no cytotoxicity, and the poly(l-lactide)-imidazolium salt films presented good cell adhesion and proliferation percentages with human mesenchymal stem cells. Furthermore, no acute microscopic lesions were identified in the histopathological evaluation after contact between the films and pig ear skin. In combination with the good morphological, physicochemical, and mechanical properties, these poly(l-lactide)-based materials with imidazolium salt additives can be considered as promising biomaterials for use in the manufacturing of medical devices.

  10. Staphylococcus aureus Quorum Regulator SarA Targeted Compound, 2-[(Methylaminomethyl]phenol Inhibits Biofilm and Down-Regulates Virulence Genes

    Directory of Open Access Journals (Sweden)

    P. Balamurugan

    2017-07-01

    Full Text Available Staphylococcus aureus is a widely acknowledged Gram-positive pathogen for forming biofilm and virulence gene expressions by quorum sensing (QS, a cell to cell communication process. The quorum regulator SarA of S. aureus up-regulates the expression of many virulence factors including biofilm formation to mediate pathogenesis and evasion of the host immune system in the late phases of growth. Thus, inhibiting the production or blocking SarA protein might influence the down-regulation of biofilm and virulence factors. In this context, here we have synthesized 2-[(Methylaminomethyl]phenol, which was specifically targeted toward the quorum regulator SarA through in silico approach in our previous study. The molecule has been evaluated in vitro to validate its antibiofilm activity against clinical S. aureus strains. In addition, antivirulence properties of the inhibitor were confirmed with the observation of a significant reduction in the expression of representative virulence genes like fnbA, hla and hld that are governed under S. aureus QS. Interestingly, the SarA targeted inhibitor showed negligible antimicrobial activity and markedly reduced the minimum inhibitory concentration of conventional antibiotics when used in combination making it a more attractive lead for further clinical tests.

  11. Biofilm inhibition formation of clinical strains of Pseudomonas aeruginosa mutans, photocatalytic activity of azo dye and GC-MS analysis of leaves of Lagerstroemia speciosa.

    Science.gov (United States)

    Sai Saraswathi, V; Kamarudheen, Neethu; Bhaskara Rao, K V; Santhakumar, K

    2017-04-01

    The investigation was conducted to analyse the bioactive compounds from the leaf extracts of L. speciosa by GC-MS. The extracts were screened for antibacterial and antibiofilm activities against potential clinical strains. The bioactive compounds from the leaves of L. speciosa were extracted by soxhlet continuous extraction method and their chemical composition was analysed by Gas Chromatography-Mass Spectroscopy (GC-MS). The antibacterial activity was evaluated against clinical strain like Staphylococcus aureus, Escherichia coli, P. aeruginosa and Salmonella typhi by well diffusion technique. We also screened for antibacterial property against common food borne pathogens namely Listeria monocytogenes and Bacillus cereus at varied concentration 250μml -1 to 1000μml -1 . Thereafter antibiofilm assay was carried out at from 250 to 1000μg/ml against P. aeruginosa (high biofilm forming pathogen) clinical strain by cover slip technique and the morphology of the pathogen was observed using Scanning Electron Microscopy-(SEM). It was observed that diverse class of secondary metabolites were found by GC-MS analysis for all the extracts upon the continuous extraction. It was found that only minimum inhibition was seen in alcoholic extract for antibacterial activity, whereas all other extracts showed negligible activity. P. aeruginosa biofilm inhibited to 93.0±2% and 91±2% at higher concentration (1000μg/ml) for methanolic and ethanolic extract respectively. Absence of extracellular matrix structure and the surface cracking of biofilm were viewed by SEM, which confirmed the antibiofilm activity. Hence this study reveals that L. speciosa showed significant antibiofilm activity against P. aeruginosa due to the phytoconstituents present in the leaf extracts which was well documented in the alcoholic extracts by GC-MS analysis. The methanolic and ethanolic extract showed good photocatalytic activity of 77.44% and 96.66% against azo dye degradation respectively. Further

  12. Inhibition of biofilm formation on the surface of water storage containers using biosand zeolite silver-impregnated clay granular and silver impregnated porous pot filtration systems.

    Science.gov (United States)

    Budeli, Phumudzo; Moropeng, Resoketswe Charlotte; Mpenyana-Monyatsi, Lizzy; Momba, Maggie Ndombo Benteke

    2018-01-01

    Development of biofilms occurring on the inner surface of storage vessels offers a suitable medium for the growth of microorganisms and consequently contributes to the deterioration of treated drinking water quality in homes. The aim of this study was to determine whether the two point-of-use technologies (biosand zeolite silver-impregnated clay granular (BSZ-SICG) filter and silver-impregnated porous pot (SIPP) filter) deployed in a rural community of South Africa could inhibit the formation of biofilm on the surface of plastic-based containers generally used by rural households for the storage of their drinking water. Culture-based methods and molecular techniques were used to detect the indicator bacteria (Total coliforms, faecal coliform, E. coli) and pathogenic bacteria (Salmonella spp., Shigella spp. and Vibrio cholerae) in intake water and on the surface of storage vessels containing treated water. Scanning electron microscopy was also used to visualize the development of biofilm. Results revealed that the surface water source used by the Makwane community was heavily contaminated and harboured unacceptably high counts of bacteria (heterotrophic plate count: 4.4-4.3 Log10 CFU/100mL, total coliforms: 2.2 Log10 CFU/100 mL-2.1 Log10 CFU/100 mL, faecal coliforms: 1.9 Log10 CFU/100 mL-1.8 Log10 CFU/100 mL, E. coli: 1.7 Log10 CFU/100 mL-1.6 Log10 CFU/100 mL, Salmonella spp.: 3 Log10 CFU/100 mL -8 CFU/100 mL; Shigella spp. and Vibrio cholerae had 1.0 Log10 CFU/100 mL and 0.8 Log10 CFU/100 mL respectively). Biofilm formation was apparent on the surface of the storage containers with untreated water within 24 h. The silver nanoparticles embedded in the clay of the filtration systems provided an effective barrier for the inhibition of biofilm formation on the surface of household water storage containers. Biofilm formation occurred on the surface of storage plastic vessels containing drinking water treated with the SIPP filter between 14 and 21 days, and on those

  13. Inhibition of biofilm formation on the surface of water storage containers using biosand zeolite silver-impregnated clay granular and silver impregnated porous pot filtration systems

    Science.gov (United States)

    Moropeng, Resoketswe Charlotte; Mpenyana-Monyatsi, Lizzy; Momba, Maggie Ndombo Benteke

    2018-01-01

    Development of biofilms occurring on the inner surface of storage vessels offers a suitable medium for the growth of microorganisms and consequently contributes to the deterioration of treated drinking water quality in homes. The aim of this study was to determine whether the two point-of-use technologies (biosand zeolite silver-impregnated clay granular (BSZ-SICG) filter and silver-impregnated porous pot (SIPP) filter) deployed in a rural community of South Africa could inhibit the formation of biofilm on the surface of plastic-based containers generally used by rural households for the storage of their drinking water. Culture-based methods and molecular techniques were used to detect the indicator bacteria (Total coliforms, faecal coliform, E. coli) and pathogenic bacteria (Salmonella spp., Shigella spp. and Vibrio cholerae) in intake water and on the surface of storage vessels containing treated water. Scanning electron microscopy was also used to visualize the development of biofilm. Results revealed that the surface water source used by the Makwane community was heavily contaminated and harboured unacceptably high counts of bacteria (heterotrophic plate count: 4.4–4.3 Log10 CFU/100mL, total coliforms: 2.2 Log10 CFU/100 mL—2.1 Log10 CFU/100 mL, faecal coliforms: 1.9 Log10 CFU/100 mL—1.8 Log10 CFU/100 mL, E. coli: 1.7 Log10 CFU/100 mL—1.6 Log10 CFU/100 mL, Salmonella spp.: 3 Log10 CFU/100 mL -8 CFU/100 mL; Shigella spp. and Vibrio cholerae had 1.0 Log10 CFU/100 mL and 0.8 Log10 CFU/100 mL respectively). Biofilm formation was apparent on the surface of the storage containers with untreated water within 24 h. The silver nanoparticles embedded in the clay of the filtration systems provided an effective barrier for the inhibition of biofilm formation on the surface of household water storage containers. Biofilm formation occurred on the surface of storage plastic vessels containing drinking water treated with the SIPP filter between 14 and 21 days, and on

  14. Controlled Release of Plectasin NZ2114 from a Hybrid Silicone-Hydrogel Material for Inhibition of Staphylococcus aureus Biofilm

    DEFF Research Database (Denmark)

    Klein, Kasper; Grønnemose, Rasmus Birkholm; Alm, Martin

    2017-01-01

    this system with plectasin derivate NZ2114 in an attempt to design an S. aureus biofilm-resistant catheter. The material demonstrated promising antibiofilm properties, including properties against methicillin-resistant S. aureus, thus suggesting a novel application of this antimicrobial peptide....

  15. Inhibited biofilm formation and improved antibacterial activity of a novel nanoemulsion against cariogenic Streptococcus mutans in vitro and in vivo

    Directory of Open Access Journals (Sweden)

    Li YF

    2015-01-01

    . CNE treatment at a concentration of 0.2 µg/mL inhibited biofilm formation more effectively than CHX, as indicated by the crystal violet staining method, scanning electron microscopy, and atomic force microscopy. The cell membrane of S. mutans was also severely disrupted by 0.2 µg/mL CNE, as indicated by transmission electron microscopy. These results demonstrated that CNE greatly improved the solubility and antimicrobial activity of this agent against S. mutans both in vitro and in vivo. This novel nanoemulsion is a promising medicine for preventing and curing dental caries. Keywords: nanoemulsion, chlorhexidine acetate, Streptococcus mutans, antibacterial

  16. Biogenic selenium and tellurium nanoparticles synthesized by environmental microbial isolates efficaciously inhibit bacterial planktonic cultures and biofilms

    Directory of Open Access Journals (Sweden)

    Emanuele eZonaro

    2015-06-01

    Full Text Available The present study deals with Se0- and Te0-based nanoparticles bio-synthesized by two selenite- and tellurite-reducing bacterial strains, namely Stenotrophomonas maltophilia SeITE02 and Ochrobactrum sp. MPV1, isolated from polluted sites. We discovered that, by regulating culture conditions and exposure time to the selenite and tellurite oxyanions, differently sized zero-valent Se and Te nanoparticles were produced. The results revealed that these Se0 and Te0 nanoparticles possess antimicrobial and biofilm eradication activity against E. coli JM109, P. aeruginosa PAO1, and S. aureus ATCC 25923. In particular, Se0 nanoparticles exhibited antimicrobial activity at quite low concentrations, below that of selenite. Toxic effects of both Se0 and Te0 nanoparticles can be related to the production of reactive oxygen species upon exposure of the bacterial cultures. Evidence so far achieved suggests that the antimicrobial activity seems to be strictly linked to the dimensions of the nanoparticles: indeed, the highest activity was shown by nanoparticles of smaller sizes. In particular, it is worth noting how the bacteria tested in biofilm mode responded to the treatment by Se0 and Te0 nanoparticles with a susceptibility similar to that observed in planktonic cultures. This suggests a possible exploitation of both Se0 and Te0 nanoparticles as efficacious antimicrobial agents with a remarkable biofilm eradication capacity.

  17. Laser-Assisted Synthesis of Mn0.50Zn0.50Fe2O4 Nanomaterial: Characterization and In Vitro Inhibition Activity towards Bacillus subtilis Biofilm

    Directory of Open Access Journals (Sweden)

    Shaukat Ali Shahid

    2015-01-01

    Full Text Available There is growing interest in the development of novel nanomaterials with potential antimicrobial activity and lesser toxicity. In the current research work, Mn0.5Zn0.5Fe2O4 nanoparticles were synthesized via a novel coprecipitation cum laser ablation technique yielding fine spinal structured material. The synthesized nanomaterial was structurally characterized by X-ray diffraction technique which confirmed the formation and the crystalline nature of Mn0.50Zn0.50Fe2O4 nanomaterial. The crystallite size determined by Debye-Scherrer’s formula was found to be ~12 nm. The formation of nanoparticles was evidenced by scanning electron microscopy. Energy dispersive X-ray analysis (EDXA was performed for elemental analysis. The synthesized nanomaterial was interestingly found to be an effective antimicrobial agent and inhibited the growth of Bacillus subtilis biofilm formation. The 5 µg of Mn0.5Zn0.5Fe2O4 nanomaterial dissolved in 1 mL of DMSO showed excellent biofilm inhibitory activity 91.23% ± 1.87 against Bacillus subtilis.

  18. Bisbibenzyls, a new type of antifungal agent, inhibit morphogenesis switch and biofilm formation through upregulation of DPP3 in Candida albicans.

    Directory of Open Access Journals (Sweden)

    Li Zhang

    Full Text Available The yeast-to-hypha transition plays a crucial role in the pathogenesis of C. albicans. Farnesol, a quorum sensing molecule (QSM secreted by the fungal itself, could prevent the formation of hyphae and subsequently lead to the defect of biofilm formation. The DPP3, encoding phosphatase, is a key gene in regulating farnesol synthesis. In this study, we screened 24 bisbibenzyls and 2 bibenzyls that were isolated from bryophytes or chemically synthesized by using CLSI method for antifungal effect. Seven bisbibenzyls were found to have antifungal effects with IC(80 less than 32 µg/ml, and among them, plagiochin F, isoriccardin C and BS-34 were found to inhibit the hyphae and biofilm formation of C. albicans in a dose-dependent manner. To uncover the underlying relationship between morphogenesis switch and QSM formation, we measured the farnesol production by HPLC-MS and quantified Dpp3 expression by detecting the fluorescent intensity of green fluorescent protein tagged strain using Confocal Laser Scanning microscopy and Multifunction Microplate Reader. The DPP3 transcripts were determined by real-time PCR. The data indicated that the bisbibenzyls exerted antifungal effects through stimulating the synthesis of farnesol via upregulation of Dpp3, suggesting a potential antifungal application of bisbibenzyls. In addition, our assay provides a novel, visual and convenient method to measure active compounds against morphogenesis switch.

  19. Screening of Furanone in Cucurbita melo and Evaluation of its Bioactive Potential Using In Silico Studies.

    Science.gov (United States)

    Singh, Nidhi; Sudandiradoss, C; Abraham, Jayanthi

    2016-12-01

    The work presented here attempts to screen for the presence of 4-Hydroxy-2,5-dimethyl-3(2H)-furanone in fruits and also any bioactive potential present in the fruit extracts. Curcurbita melo was selected for the study, and the fruit was crushed, filtered and extracted with ethyl acetate as the solvent. The resulting extract was subjected to disk diffusion test using Kirby Bauer method for checking its antimicrobial potential. Melon extract showed promising results against different clinical pathogens, 19-mm zone being the largest against Klebsiella pneumoniae and 17 mm against Shigella dysenteriae. GC-MS data of the melon extract confirmed the existence of furanone derivative in the extract. To evaluate the antimicrobial activity, in silico studies were performed using AutoDock 4.0 software, and topoisomerase was used as the target protein molecule for the isolated compound and 3-methyl-2-(2-oxopropyl)furan as the ligand. Further, the results were interpreted using PyMol and Ligplot plus softwares. The results confirmed the presence of molecular interactions between the protein molecule and the ligand. It can be envisaged that these interactions are responsible for the inhibitory effects of the extract .

  20. Biofilm Risks

    DEFF Research Database (Denmark)

    Wirtanen, Gun Linnea; Salo, Satu

    2016-01-01

    This chapter on biofilm risks deals with biofilm formation of pathogenic microbes, sampling and detection methods, biofilm removal, and prevention of biofilm formation. Several common pathogens produce sticky and/or slimy structures in which the cells are embedded, that is, biofilms, on various...... surfaces in food processing. Biofilms of common foodborne pathogens are reviewed. The issue of persistent and nonpersistent microbial contamination in food processing is also discussed. It has been shown that biofilms can be difficult to remove and can thus cause severe disinfection and cleaning problems...... in food factories. In the prevention of biofilm formation microbial control in process lines should both limit the number of microbes on surfaces and reduce microbial activity in the process. Thus the hygienic design of process equipment and process lines is important in improving the process hygiene...

  1. Salmonella biofilms

    NARCIS (Netherlands)

    Castelijn, G.A.A.

    2013-01-01

    Biofilm formation by Salmonellaspp. is a problem in the food industry, since biofilms may act as a persistent source of product contamination. Therefore the aim of this study was to obtain more insight in the processes involved and the factors contributing to Salmonellabiofilm

  2. Asymmetric 1,3-Dipolar Cycloadditions to 5-(R)-Menthyloxy-2(5H)-Furanone

    NARCIS (Netherlands)

    Rispens, Minze T.; Keller, Erik; Lange, Ben de; Zijlstra, Robert W.J.; Feringa, Bernard

    Various diazo compounds, nitrile oxides, nitrones and azomethine ylides were examined in 1,3-dipolar cycloadditions to enantiomerically pure 5-(R)-menthyloxy-2(5H)-furanone 1a. Pyrazoline 9 was obtained in 100% c.y. as a mixture of 2 diastereoisomers in ratios up to 72 : 28, whereas pyrazoline 16

  3. PHENYLSULFONYL-SUBSTITUTED 5-ALKOXY-2(5H)-FURANONES - A NEW CLASS OF HIGHLY REACTIVE CHIRAL DIENOPHILES

    NARCIS (Netherlands)

    DEJONG, JC; VANDENBERG, KJ; FERINGA, BL; van Leusen, A.M.

    1991-01-01

    The synthesis of enantiomerically pure (5S)-5-(d-menthyloxy)-4-(phenylsulfonyl)-2(5H)-furanone (4) and the application of 4 as efficient dienophile in Diels-Alder reactions under mild conditions with enantioselectivities > 98% e.e. are described.

  4. Microbial biofilms: biosurfactants as antibiofilm agents.

    Science.gov (United States)

    Banat, Ibrahim M; De Rienzo, Mayri A Díaz; Quinn, Gerry A

    2014-12-01

    Current microbial inhibition strategies based on planktonic bacterial physiology have been known to have limited efficacy on the growth of biofilm communities. This problem can be exacerbated by the emergence of increasingly resistant clinical strains. All aspects of biofilm measurement, monitoring, dispersal, control, and inhibition are becoming issues of increasing importance. Biosurfactants have merited renewed interest in both clinical and hygienic sectors due to their potential to disperse microbial biofilms in addition to many other advantages. The dispersal properties of biosurfactants have been shown to rival those of conventional inhibitory agents against bacterial and yeast biofilms. This makes them suitable candidates for use in new generations of microbial dispersal agents and for use as adjuvants for existing microbial suppression or eradication strategies. In this review, we explore aspects of biofilm characteristics and examine the contribution of biologically derived surface-active agents (biosurfactants) to the disruption or inhibition of microbial biofilms.

  5. Biofilm Infections

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Jensen, Peter Østrup; Moser, Claus Ernst

    A still increasing interest and emphasis on the sessile bacterial lifestyle biofilms has been seen since it was realized that the vast majority of the total microbial biomass exists as biofilms. Aggregation of bacteria was first described by Leeuwenhoek in 1677, but only recently recognized...... as being important in chronic infection. In 1993 the American Society for Microbiology (ASM) recognized that the biofilm mode of growth was relevant to microbiology. This book covers both the evidence for biofilms in many chronic bacterial infections as well as the problems facing these infections...... such as diagnostics, pathogenesis, treatment regimes and in vitro and in vivo models for studying biofilms. This is the first scientific book on biofilm infections, chapters written by the world leading scientist and clinicians. The intended audience of this book is scientists, teachers at university level as well...

  6. The Development of Nitroxide Based Coatings for Biofilm Remediation- 154020

    Science.gov (United States)

    2017-06-05

    combat biofilm formation and growth is to use small molecules that act through non-microbicidal mechanisms to inhibit and/or disperse biofilms ...of materials (such as titanium, stainless steel , aluminium etc.)? Experiment: Our approaches used to address each of the fundamental challenges are...surfaces for inhibition of biofilm growth in a static assay has shown that the surfaces have little effect on biofilm formation . This result is very

  7. Staphylococcus aureus biofilm removal by targeting biofilm-associated extracellular proteins

    Directory of Open Access Journals (Sweden)

    Sudhir K Shukla

    2017-01-01

    Methods: Biofilm assay was done in 96-well microtitre plate to evaluate the effect of proteinase K on biofilms of bovine mastitis S. Aureus isolates. Extracellular polymeric substances were extracted and evaluated for their composition (protein, polysaccharides and extracellular DNA, before and after the proteinase K treatment. Results: Biofilm assay showed that 2 μg/ml proteinase K significantly inhibited biofilm development in bap-positive S. aureus V329 as well as other S. aureus isolates (SA7, SA10, SA33, SA352, but not in bap-mutant M556 and SA392 (a weak biofilm-producing strain. Proteinase K treatment on S. aureus planktonic cells showed that there was no inhibition of planktonic growth up to 32 μg/ml of proteinase K. Proteinase K treatment on 24 h old preformed biofilms showed an enhanced dispersion of bap-positive V329 and SA7, SA10, SA33 and SA352 biofilms; however, proteinase K did not affect the bap-mutant S. aureus M556 and SA392 biofilms. Biofilm compositions study before and after proteinase K treatment indicated that Bap might also be involved in eDNA retention in the biofilm matrix that aids in biofilm stability. When proteinase K was used in combination with antibiotics, a synergistic effect in antibiotic efficacy was observed against all biofilm-forming S. aureus isolates. Interpretation & conclusions: Proteinase K inhibited biofilms growth in S. aureus bovine mastitis isolates but did not affect their planktonic growth. An enhanced dispersion of preformed S. aureus biofilms was observed on proteinase K treatment. Proteinase K treatment with antibiotics showed a synergistic effect against S. aureus biofilms. The study suggests that dispersing S. aureus by protease can be of use while devising strategies againstS. aureus biofilms.

  8. Application of stable isotope ratio analysis explaining the bioformation of 2,5-dimethyl-4-hydroxy-3(2H)-furanone in plants by a biological Maillard reaction

    International Nuclear Information System (INIS)

    Schwab, W.

    1998-01-01

    [1-13C]-D-Fructose and [U-13C6]-D-fructose were applied to detached ripening strawberry fruits, and the incorporation into 2,5-dimethyl-4-hydroxy-3(2H)-furanone 1, 2,5-dimethyl-4-methoxy-3(2H)-furanone 2, 2,5-dimethyl-4-acetoxy-3(2H)-furanone 3, 2,5-dimethyl-4-hydroxy-3(2H)-furanone beta-D-glucopyranoside 4, and 2,5-dimethyl-4-hydroxy-3(2H)-furanone 6'-O-malonyl beta-D-glucopyranoside 5 was determined by HRGC-MS and HPLC-ESI MS-MS. The data clearly showed the direct conversion of D-fructose to the furanones without cleavage of the carbohydrate prior to the formation of 1-5, as expected for a biological Maillard reaction. Both, the furanone and the D-glucose moiety of 4 and 5 contained the labels. However, the label was primarily incorporated into the furanone moiety, indicating that D-fructose is a more efficient precursor of the furanones than D-glucose

  9. Biofilm Development

    DEFF Research Database (Denmark)

    Tolker-Nielsen, Tim

    2015-01-01

    During the past decade we have gained much knowledge about the molecular mechanisms that are involved in initiation and termination of biofilm formation. In many bacteria, these processes appear to occur in response to specific environmental cues and result in, respectively, induction or terminat......During the past decade we have gained much knowledge about the molecular mechanisms that are involved in initiation and termination of biofilm formation. In many bacteria, these processes appear to occur in response to specific environmental cues and result in, respectively, induction...... or termination of biofilm matrix production via the second messenger molecule c-di-GMP. In between initiation and termination of biofilm formation we have defined specific biofilm stages, but the currently available evidence suggests that these transitions are mainly governed by adaptive responses......, and not by specific genetic programs. It appears that biofilm formation can occur through multiple pathways and that the spatial structure of the biofilms is species dependent as well as dependent on environmental conditions. Bacterial subpopulations, e.g., motile and nonmotile subpopulations, can develop...

  10. The ATP-Dependent Protease ClpP Inhibits Biofilm Formation by Regulating Agr and Cell Wall Hydrolase Sle1 in Staphylococcus aureus

    Science.gov (United States)

    Liu, Qian; Wang, Xing; Qin, Juanxiu; Cheng, Sen; Yeo, Won-Sik; He, Lei; Ma, Xiaowei; Liu, Xiaoyun; Li, Min; Bae, Taeok

    2017-01-01

    Biofilm causes hospital-associated infections on indwelling medical devices. In Staphylococcus aureus, Biofilm formation is controlled by intricately coordinated network of regulating systems, of which the ATP-dependent protease ClpP shows an inhibitory effect. Here, we demonstrate that the inhibitory effect of ClpP on biofilm formation is through Agr and the cell wall hydrolase Sle1. Biofilm formed by clpP mutant consists of proteins and extracellular DNA (eDNA). The increase of the protein was, at least in part, due to the reduced protease activity of the mutant, which was caused by the decreased activity of agr. On the other hand, the increase of eDNA was due to increased cell lysis caused by the higher level of Sle1. Indeed, as compared with wild type, the clpP mutant excreted an increased level of eDNA, and showed higher sensitivity to Triton-induced autolysis. The deletion of sle1 in the clpP mutant decreased the biofilm formation, the level of eDNA, and the Triton-induced autolysis to wild-type levels. Despite the increased biofilm formation capability, however, the clpP mutant showed significantly reduced virulence in a murine model of subcutaneous foreign body infection, indicating that the increased biofilm formation capability cannot compensate for the intrinsic functions of ClpP during infection. PMID:28555174

  11. The ATP-Dependent Protease ClpP Inhibits Biofilm Formation by Regulating Agr and Cell Wall Hydrolase Sle1 in Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Qian Liu

    2017-05-01

    Full Text Available Biofilm causes hospital-associated infections on indwelling medical devices. In Staphylococcus aureus, Biofilm formation is controlled by intricately coordinated network of regulating systems, of which the ATP-dependent protease ClpP shows an inhibitory effect. Here, we demonstrate that the inhibitory effect of ClpP on biofilm formation is through Agr and the cell wall hydrolase Sle1. Biofilm formed by clpP mutant consists of proteins and extracellular DNA (eDNA. The increase of the protein was, at least in part, due to the reduced protease activity of the mutant, which was caused by the decreased activity of agr. On the other hand, the increase of eDNA was due to increased cell lysis caused by the higher level of Sle1. Indeed, as compared with wild type, the clpP mutant excreted an increased level of eDNA, and showed higher sensitivity to Triton-induced autolysis. The deletion of sle1 in the clpP mutant decreased the biofilm formation, the level of eDNA, and the Triton-induced autolysis to wild-type levels. Despite the increased biofilm formation capability, however, the clpP mutant showed significantly reduced virulence in a murine model of subcutaneous foreign body infection, indicating that the increased biofilm formation capability cannot compensate for the intrinsic functions of ClpP during infection.

  12. Effect of curcumin on Helicobacter pylori biofilm formation ...

    African Journals Online (AJOL)

    Three-dimensional structure of biofilm was imaged by scanning electron microscopy. The effect of curcumin on H. pylori adherence to HEp-2 cells was also investigated. Subinhibitory concentrations of curcumin inhibited the biofilm in dose dependent manner. However, H.pylori could restore ability to form biofilm during ...

  13. Inhibition of the early stage of Salmonella enterica serovar Enteritidis biofilm development on stainless steel by cell-free supernatant of a Hafnia alvei culture.

    Science.gov (United States)

    Chorianopoulos, Nikos G; Giaouris, Efstathios D; Kourkoutas, Yiannis; Nychas, George-John E

    2010-03-01

    Compounds present in Hafnia alvei cell-free culture supernatant cumulatively negatively influence the early stage of biofilm development by Salmonella enterica serovar Enteritidis on stainless steel while they also reduce the overall metabolic activity of S. Enteritidis planktonic cells. Although acylhomoserine lactones (AHLs) were detected among these compounds, the use of several synthetic AHLs was not able to affect the initial stage of biofilm formation by this pathogen.

  14. Wound biofilms: lessons learned from oral biofilms

    OpenAIRE

    Mancl, Kimberly A.; Kirsner, Robert S.; Ajdic, Dragana

    2013-01-01

    Biofilms play an important role in the development and pathogenesis of many chronic infections. Oral biofilms, more commonly known as dental plaque,are a primary cause of oral diseases including caries, gingivitis and periodontitis. Oral biofilms are commonly studied as model biofilm systems as they are easily accessible, thus biofilm research in oral diseases is advanced with details of biofilm formation and bacterial interactions being well-elucidated. In contrast, wound research has relati...

  15. Biofilm inhibitors that target amyloid proteins.

    Science.gov (United States)

    Romero, Diego; Sanabria-Valentín, Edgardo; Vlamakis, Hera; Kolter, Roberto

    2013-01-24

    Bacteria establish stable communities, known as biofilms, that are resistant to antimicrobials. Biofilm robustness is due to the presence of an extracellular matrix, which for several species-among them Bacillus subtilis-includes amyloid-like protein fibers. In this work, we show that B. subtilis biofilms can be a simple and reliable tool for screening of molecules with antiamyloid activity. We identified two molecules, AA-861 and parthenolide, which efficiently inhibited biofilms by preventing the formation of amyloid-like fibers. Parthenolide also disrupted pre-established biofilms. These molecules also impeded the formation of biofilms of other bacterial species that secrete amyloid proteins, such as Bacillus cereus and Escherichia coli. Furthermore, the identified molecules decreased the conversion of the yeast protein New1 to the prion state in a heterologous host, indicating the broad range of activity of the molecules. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Effect of chlorine treatment on inhibition of E. coli serogroup O2 incorporation into 7-day-old biofilm on polyvinylchloride surface.

    Science.gov (United States)

    Maharjan, P; Dey, S; Huff, G; Zhang, W; Phillips, G K; Watkins, S

    2017-08-01

    Poultry waterlines are constructed using polyvinylchloride (PVC) material on which bacterial biofilm can easily form. Biofilm can harbor pathogens including avian pathogenic E. coli (APEC) strains. An in vitro evaluation was performed to determine if E. coli sero group O2 (avian pathogenic) could attach on a PVC surface that had pre-formed biofilm and if this phenomenon could be affected when water was treated with chlorine. Initially, biofilm growth was induced in PVC test coupons (15.16 cm2) for a 7-day period mimicking the waterline scenario in the first wk of poultry brooding; and then this biofilm was challenged with E. coli O2 seeded water in presence/absence of chlorine treatment. After rinsing, test coupons were sampled for bacterial (APC) and E. coli O2 enumeration at various occasions post seeding the pathogen and chlorine treatment. Day 7 APC recovered from coupons was 4.35 log10 cfu/cm2 in trial 1 and 3.66 log10 cfu/cm2 in trial 2. E. coli O2 was not recovered from chlorine treated test coupons (P  3 log10 cfu/cm2 in trial 1 and > 2 log10 cfu/cm2 in trial 2). This study suggests that E. coli O2 can incorporate into pre-formed biofilm on a PVC surface within 24 h if water sanitation is not present, and the attachment time of the pathogen can prolong in the absence of already formed biofilm. © 2017 Poultry Science Association Inc.

  17. Evaluation of Energy Dose and Output Power Optimum of Diode’s Laser of 450 nm and 650 nm in Photoantimicrobial Mechanisms Against Inhibition of C. Albicans Biofilm Cells

    Science.gov (United States)

    Dewi-Astuty, S.; Suhariningsih; Dyah-Astuti, S.; Baktir, A.

    2018-03-01

    Photoantimicrobial as a pathogenic microbial inhibitory therapy system such as C. albicans in biofilms forms has been studied in vitro. Mechanisms of inhibiting called inactivating used the absorb principles of a dye agents such as chlorophyll against the photon energy of diode laser which any number of ROS product depend on energy doses of a laser, time of irradiation, concentration and time of incubation the dyes agent. The inactivation profile of C. albicans biofilm cells was observed based on cell viability reduction after photoantimicrobial treatment with or without oxygenation by XTT assay test. Results show that the inhibiting significantly with the time incubation of the dye agents and the oxygen degree inside the sample. The inhibition for oxygenation biofilm’s group 10% lower than without oxygenation biofilm’s group at the maximum of reduction of cell viability occurred in the 3hour incubation group. Optimum of inactivation are 89.6% (without oxygenation) and 94.8% (with oxygenation) after irradiation with 450 nm laser (power output 128.73 at energy dose 86.09 J/cm2), While, by 650 nm laser (power output 164.53 mW at energy dose 92.52 J/cm2) irradiation treatment obtained optimum of inactivation are 89.5% (without oxygenation) and 92.3% (with oxygenation).

  18. Biosynthesis of 4-hydroxy-2,5-dimethyl-3(2H)-furanone and derivatives in in vitro grown strawberries.

    Science.gov (United States)

    Pérez, A G; Olías, R; Olías, J M; Sanz, C

    1999-02-01

    The biosynthesis of 2,5-dimethyl-4-hydroxy-3(2H)-furanone (Furaneol) and its methyl ether and glucoside derivatives has been studied in strawberries. An in vitro system was used for growing this fruit, showing that the presence in the incubation medium of sucrose or hydroxyquinoline hemisulfate has no effect on the bioformation of these compounds. Strawberries in vitro grown showed an increase in furanone content with time, especially between the second and fourth days, to the same extent as field-grown fruits but at a higher rate. Among the precursors added to the incubation medium, D-fructose gave rise to an increase in furaneol and its glucoside derivative of 42. 6% and 26.3%, respectively. D-fructose 6-phosphate seems to be the precursor of furaneol in strawberries since, when present in the incubation medium, it produced an average increase of 125% in all furanones contents with respect to control fruits.

  19. Tautomerism of 4-hydroxy-2,5-dimethyl-3(2H)-furanone: evidence for its enantioselective biosynthesis.

    Science.gov (United States)

    Raab, Thomas; Hauck, Tobias; Knecht, Anja; Schmitt, Ulrich; Holzgrabe, Ulrike; Schwab, Wilfried

    2003-08-01

    Chiral natural flavor compounds exhibit characteristic enantiomeric excesses due to stereoselective, enzymatically catalyzed reactions during biogenesis. Although the enzymatic formation of the strawberry key flavor compound 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF; Furaneol(R)) is anticipated, the naturally occurring compound is racemic. As racemization due to keto-enol-tautomerism of HDMF could account for this observation, HDMF was investigated by (1)H-NMR spectroscopy tracing the exchange of the proton bound to the furanone-ring at C2 with deuteron from the medium (D(2)O). In addition, the racemization rate of HDMF was directly determined by cyclodextrin-modified capillary electrophoresis of enantiomerically enriched HDMF stored at different pH values. Tautomerism and the racemization rate of HDMF was lowest at pH values between 4 and 5. However, tautomerism and thus racemization was catalyzed under stronger acidic conditions (pH 2) and especially at pH values greater than 7, the value published for plant cell cytosol. Approximately 50% of the protons at C2 were exchanged with deuteron within 1 h at pH 7.2. Therefore, in order to demonstrate the enzymatic formation of HDMF, incubation experiments with Zygosaccharomyces rouxii as well as strawberry protein extract were carried out under slightly acidic conditions (pH 5), the most suitable pH value for studies on the enantiomeric ratio of HDMF. In both experiments the formation of enantiomerically enriched HDMF could be demonstrated for the first time, whereas incubation experiments under neutral conditions resulted in the detection of racemic HDMF. Copyright 2003 Wiley-Liss, Inc.

  20. Synthesis of carbon-14 labelled (5Z)-4-bromo-5-(bromomethylene)-2(5H)-furanone:

    DEFF Research Database (Denmark)

    Persson, T.; Johansen, S.K.; Martiny, L.

    2004-01-01

    The potent quorum sensing inhibitor (5Z)-4-bromo-5-(bromomethylene)-2(5H)-[2-C-14]furanone has been prepared in five steps in 7.7% overall yield starting from bromo[1-C-14]acetic acid. Condensation of ethyl bromo[1-C-14]acetate with ethyl acetoacetate followed by decarboxylation was accelerated...... by microwave heating to afford [1-C-14]levulinic acid. Subsequently, bromination and oxidation gave the targeted furan-2-one with a radiochemical purity of > 97% and a specific activity of 57 mCi/mmol....

  1. Synthesis, reactions and biological activity of 3-arylidene-5-(4-methylphenyl-2(3H-furanones

    Directory of Open Access Journals (Sweden)

    ASIF HUSAIN

    2009-02-01

    Full Text Available 3-Arylidene-5-(4-methylphenyl-2(3H-furanones 2a–m were prepared from 3-(4-methyl-benzoylpropanoic acid 1 and several aromatic aldehydes. Some of the selected furanones were reacted with ammonia gas and benzylamine to give corresponding 3-arylidene-1,3-dihydro-5-(4-methylphenyl-2H-pyrrol-2-ones 3a–h and 3-arylidene-1-benzyl-1,3-dihydro-5-(4-methylphenyl-2H-pyrrol-2-ones 4a–f, respectively, which were characterized on the basis of IR, 1H-NMR, mass spectral data and elemental analysis results. These compounds were tested for their anti-inflammatory and antibacterial activities. The compounds, which showed significant anti-inflammatory activity, were further screened for their analgesic and ulcerogenic activities. Three new compounds (2e, 2h and 4d, out of twenty-seven showed very good anti-inflammatory activity in the carrageenan induced rat paw edema test, with significant analgesic activity in the acetic acid induced writhing test together with negligible ulcerogenic action. The antibacterial activity is expressed as the corresponding MIC values.

  2. Inhibitory effect of farnesol on biofilm formation by Candida tropicalis

    Directory of Open Access Journals (Sweden)

    E Zibafar

    2009-03-01

    Full Text Available ABSTRACT Background: Candidiasis associated with indwelling medical devices is especially problematic since they can act as substrates for biofilm growth which are highly resistant to antifungal drugs. Farnesol is a quorum-sensing molecule that inhibits filamentation and biofilm formation in Candida albicans. Since in recent years Candida tropicalis have been reported as an important and common non-albicans Candida species with high drug resistance pattern, the inhibitory effect of farnesol on biofilm formation by Candida tropicalis was evaluated. Methods: Five Candida tropicalis strains were treated with different concentration of farnesol (0, 30 and 300 µM after 0, 1 and 4 hrs of adherence and then they were maintained under biofilm formation condition in polystyrene, 96-well microtiter plates at 37°C for 48 hrs. Biofilm formation was measured by a semiquantitative colorimetric technique based on reduction assay of 2,3- bis  -2H-tetrazolium- 5- carboxanilide (XTT. Results: The results indicated that the initial adherence time had no effect on biofilm formation and low concentration of farnesol (30 µM could not inhibit biofilm formation. However the presence of non-adherent cells increased biofilm formation significantly and the high concentration of farnesol (300 µM could inhibit biofilm formation. Conclusion: Results of this study showed that the high concentration of farnesol could inhibit biofilm formation and may be used as an adjuvant in prevention and in therapeutic strategies with antifungal drugs.

  3. DNase I and proteinase K impair Listeria monocytogenes biofilm formation and induce dispersal of pre-existing biofilms.

    Science.gov (United States)

    Nguyen, Uyen T; Burrows, Lori L

    2014-09-18

    Current sanitation methods in the food industry are not always sufficient for prevention or dispersal of Listeria monocytogenes biofilms. Here, we determined if prevention of adherence or dispersal of existing biofilms could occur if biofilm matrix components were disrupted enzymatically. Addition of DNase during biofilm formation reduced attachment (biofilms with 100μg/ml of DNase for 24h induced incomplete biofilm dispersal, with biofilm remaining compared to control. In contrast, addition of proteinase K completely inhibited biofilm formation, and 72h biofilms-including those grown under stimulatory conditions-were completely dispersed with 100μg/ml proteinase K. Generally-regarded-as-safe proteases bromelain and papain were less effective dispersants than proteinase K. In a time course assay, complete dispersal of L. monocytogenes biofilms from both polystyrene and type 304H food-grade stainless steel occurred within 5min at proteinase K concentrations above 25μg/ml. These data confirm that both DNA and proteins are required for L. monocytogenes biofilm development and maintenance, and that these components of the biofilm matrix can be targeted for effective prevention and removal of biofilms. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Effects of L-cysteine and N-acetyl-L-cysteine on 4-hydroxy-2, 5-dimethyl-3(2H)-furanone (furaneol), 5-(hydroxymethyl)furfural, and 5-methylfurfural formation and browning in buffer solutions containing either rhamnose or glucose and arginine.

    Science.gov (United States)

    Haleva-Toledo, E; Naim, M; Zehavi, U; Rouseff, R L

    1999-10-01

    Solutions of L-cysteine (Cys) and N-acetyl-L-cysteine (AcCys), containing glucose or rhamnose, with or without arginine, were buffered to pH 3, 5, and 7 and incubated at 70 degrees C for 48 h. Cys and AcCys inhibited the formation of (hydroxymethyl)furfural (HMF) from glucose and methylfurfural (MF) from rhamnose under acidic conditions. AcCys inhibited the accumulation of 4-hydroxy-2, 5-dimethyl- 3(2H)-furanone (DMHF, Furaneol) from rhamnose, but Cys, under our experimental conditions, enhanced Furaneol accumulation from rhamnose. Cys and AcCys reacted directly with Furaneol but not with HMF or MF. Both Cys and AcCys inhibited nonenzymatic browning at pH 7. At pH 3, however, Cys reacted with both glucose and rhamnose to produce unidentified compounds that increased the visible absorbency.

  5. Hydraulic resistance of biofilms

    KAUST Repository

    Dreszer, C.; Vrouwenvelder, Johannes S.; Paulitsch-Fuchs, Astrid H.; Zwijnenburg, Arie; Kruithof, Joop C.; Flemming, Hans Curt

    2013-01-01

    resistance is very low compared to the expected biofilm resistance and, thus, biofilm resistance can be determined accurately. Transmembrane pressure drop was monitored. As biofilm parameters, thickness, total cell number, TOC, and extracellular polymeric

  6. Radiotracer studies on the formation of 2,5-dimethyl-4-hydroxy-3(2H)-furanone in detached ripening strawberry fruits

    International Nuclear Information System (INIS)

    Roscher, R.; Bringmann, G.; Schreier, P.; Schwab, W.

    1998-01-01

    The transformation of 12 radioactively labeled compounds into 2,5-dimethyl-4-hydroxy-3(2H)-furanone (DMHF), glycosidically bound DMHF, and 2,5-dimethyl-4-methoxy-3(2H)-furanone (DMMF) was investigated in detached ripening strawberry fruits (Fragaria x ananassa) over a 3-day period. Radiochemical analysis of the different fruit parts revealed that major portions of the applied radioactivity (up to 66%) remained in the stems and calyx. Incorporation levels of [2- 14 C]-dihydroxyacetone, D-[1- 3 H]glucose, D-[U- 14 C]-glucose, D-[U- 14 C]glucose 6-phosphate, D-[U- 14 C]fructose, and D-[U- 14 C]fructose 1,6-bisphosphate into the total amount of furanone derivatives were 0.022, 0.032, 0.035, 0.147, 0.202, and 0.289% of the radioactivity entering the fruits, respectively. Minor amounts of radioactivity (0.001%) were detected in the furanone structures after the administration of [1- 14 C]acetate and [3- 14 C]pyruvate. L-[1- 14 C]Fucose, L-[6- 3 H]fucose, L-[1- 3 H]rhamnose, L-[U- 14 C]-threonine, L-[U- 14 C]lactaldehyde, and [2- 14 C]malonic acid were not transformed into DMHF or a derivative thereof. (author)

  7. Anti-Candida albicans biofilm effect of novel heterocyclic compounds.

    Science.gov (United States)

    Kagan, Sarah; Jabbour, Adel; Sionov, Edward; Alquntar, Abed A; Steinberg, Doron; Srebnik, Morris; Nir-Paz, Ran; Weiss, Aryeh; Polacheck, Itzhack

    2014-02-01

    The aims of this study were to develop new anti-biofilm drugs, examine their activity against Candida albicans biofilm and investigate their structure-activity relationship and mechanism of action. A series of thiazolidinedione and succinimide derivatives were synthesized and their ability to inhibit C. albicans biofilm formation and destroy pre-formed biofilm was tested. The biofilms' structure, metabolic activity and viability were determined by XTT assay and propidium iodide and SYTO 9 live/dead stains combined with confocal microscopic analysis. The effect of the most active compounds on cell morphology, sterol distribution and cell wall morphology and composition was then determined by specific fluorescent stains and transmission electron microscopy. Most of the compounds were active at sub-MICs. Elongation of the aliphatic side chain resulted in reduced anti-biofilm activity and the sulphur atom contributed to biofilm killing, indicating a structure-activity relationship. The compounds differed in their effects on biofilm viability, yeast-to-hyphal form transition, hyphal morphology, cell wall morphology and composition, and sterol distribution. The most effective anti-biofilm compounds were the thiazolidinedione S8H and the succinimide NA8. We developed novel anti-biofilm agents that both inhibited and destroyed C. albicans biofilm. With some further development, these agents might be suitable for therapeutic purposes.

  8. The in vitro effect of xylitol on chronic rhinosinusitis biofilms.

    Science.gov (United States)

    Jain, R; Lee, T; Hardcastle, T; Biswas, K; Radcliff, F; Douglas, R

    2016-12-01

    Biofilms have been implicated in chronic rhinosinusitis (CRS) and may explain the limited efficacy of antibiotics. There is a need to find more effective, non-antibiotic based therapies for CRS. This study examines the effects of xylitol on CRS biofilms and planktonic bacteria. Crystal violet assay and spectrophotometry were used to quantify the effects of xylitol (5% and 10% solutions) against Staphylococcus epidermidis, Pseudomonas aeruginosa, and Staphylococcus aureus. The disruption of established biofilms, inhibition of biofilm formation and effects on planktonic bacteria growth were investigated and compared to saline and no treatment. Xylitol 5% and 10% significantly reduced biofilm biomass (S. epidermidis), inhibited biofilm formation (S. aureus and P. aeruginosa) and reduced growth of planktonic bacteria (S. epidermidis, S. aureus, and P. aeruginosa). Xylitol 5% inhibited formation of S. epidermidis biofilms more effectively than xylitol 10%. Xylitol 10% reduced S. epidermidis planktonic bacteria more effectively than xylitol 5%. Saline, xylitol 5% and 10% disrupted established biofilms of S. aureus when compared with no treatment. No solution was effective against established P. aeruginosa biofilm. Xylitol has variable activity against biofilms and planktonic bacteria in vitro and may have therapeutic efficacy in the management of CRS.

  9. Effects of Miramistin and Phosprenil on Microbial Biofilms.

    Science.gov (United States)

    Danilova, T A; Danilina, G A; Adzhieva, A A; Minko, A G; Nikolaeva, T N; Zhukhovitskii, V G; Pronin, A V

    2017-08-01

    Effects of Miramistin and Phosprenil on biofilms of S. pyogenes, S. aureus, E. coli, L. acidophilus, and L. plantarum were studied. Significant differences in the effects of these substances on mature biofilms of microorganisms and the process of their formation were observed. Miramistin had significant inhibiting effects on the forming of biofilms and on the formed biofilms of all studied microorganisms. Treatment with Miramistin inhibited biofilm formation by 2-3 times compared to the control. This effect was found already after using of Miramistin in the low doses (3.12 μg/ml). Inhibition of the growth of a formed biofilm was observed only after treatment with Miramistin in the high doses (25-50 μg/ml). Phosprenil in the high doses (15-30 mg/ml) inhibited the forming of biofilms, especially the biofilms of S. pyogenes and L. plantarum (by 3-4.5 times). Treatment of formed biofilms with the agent in doses of 6.0 and 0.6 mg/ml was associated with pronounced stimulation of its growth in S. pyogenes, S. aureus, and L. acidophilus.

  10. The possible role of bacterial signal molecules N-acyl homoserine lactones in the formation of diatom-biofilm (Cylindrotheca sp.)

    International Nuclear Information System (INIS)

    Yang, Cuiyun; Fang, Shengtao; Chen, Dehui; Wang, Jianhua; Liu, Fanghua; Xia, Chuanhai

    2016-01-01

    Bacterial quorum sensing signal molecules N-acyl homoserine lactones (AHLs) (C10-HSL, 3-OXO-C10-HSL and 3-OH-C10-HSL) as possible chemical cues were employed to investigate the role in the formation of fouling diatom-biofilm (Cylindrotheca sp.). Results showed that AHLs promoted Chlorophyll a (Chl.a) and extracellular polymeric substance (EPS) contents in the diatom-biofilm. In the presence of AHLs-inhibitor 3, 4-Dibromo-2(5)H-furanone, which was used to avoid the possible interference of AHLs from bacteria, AHLs also increased the Chl.a and EPS contents. Scanning electron microscope and confocal laser scanning microscope analysis further demonstrated that AHLs promoted the formation of the diatom-biofilm. Non-invasive micro-test technique showed that AHLs promoted Ca 2+ efflux in Cylindrotheca sp., which implied that Ca 2+ might be correlated with AHLs-induced positive effect on the formation of diatom-biofilm. This study provides direct evidences that AHLs play an important role in developing the diatom-biofilm and AHLs-inhibitors might be promising active agents in marine antifouling. - Highlights: •AHLs effectively increase Chl.a and EPS contents in diatom-biofilm. •SEM and CLSM further demonstrate that AHLs promote the formation of diatom-biofilm. •AHLs trigger algal cellular Ca 2+ efflux. •AHLs-inhibitors might be promising active agents in marine antifouling.

  11. Chemoinformatics-assisted development of new anti-biofilm compounds

    DEFF Research Database (Denmark)

    Dürig, Anna; Kouskoumvekaki, Irene; Vejborg, Rebecca Munk

    2010-01-01

    Bacterial biofilms are associated with a large number of infections. Biofilm-dwelling bacteria are particularly resistant to antibiotics, making it hard to eradicate biofilm-associated infections. Here, we use a novel cross-disciplinary approach combining microbiology and chemoinformatics...... to identify new and efficient anti-biofilm drugs. We found that ellagic acid (present in green tea) significantly inhibited biofilm formation of Streptococcus dysgalactiae. Based on ellagic acid, we performed in silico screening of the Chinese Natural Product Database to predict a 2nd-generation list...... of compounds with similar characteristics. One of these, esculetin, proved to be more efficient in preventing biofilm formation by Staphylococcus aureus. From esculetin a 3rd-generation list of compounds was predicted. One of them, fisetin, was even better to abolish biofilm formation than the two parent...

  12. Layer-by-layer self-assembly of minocycline-loaded chitosan/alginate multilayer on titanium substrates to inhibit biofilm formation.

    Science.gov (United States)

    Lv, Hongbin; Chen, Zhen; Yang, Xiaoping; Cen, Lian; Zhang, Xu; Gao, Ping

    2014-11-01

    Bacteria adhesion and subsequent biofilm formation are primary causes of implant associated infection. The biofilm makes the bacteria highly resistant to the host defense and antimicrobial treatment. Antibacterial coatings on the surface of titanium implant can prevent biofilm formation effectively, but it is still a challenge to accomplish relatively long lasting antibacterial effects before wound healing or formation of biological seal. The purpose of our work was to construct antibacterial multilayer coatings loaded with minocycline on surface of Ti substrates using chitosan and alginate based on layer-by-layer (LbL) self-assembly technique. In this study, the surfaces of Ti substrates were first hydroxylated and then treated with 3-aminopropyltriethoxysilane (ATPES) to obtain amino-functionalized Ti substrates. Next, the precursor layer of chitosan was covalently conjugated to amino-functionalized Ti substrates. The following alternately coating alginate loaded with minocycline and chitosan onto the precursor layer of chitosan was carried out via LbL self-assembly technique to construct the multilayer coatings on Ti substrates. The multilayer coatings loaded more minocycline and improved sustainability of minocycline release to kill planktonic and adherent bacteria. Moreover, surface charge and hydrophilicity of the coatings and antibacterial ability of chitosan itself also played roles in the antibacterial performance, which can keep the antibacterial ability of the multilayer coatings after minocycline release ceases. In conclusion, LbL self-assembly method provides a promising strategy to fabricate long-term antibacterial surfaces, which is especially effective in preventing implant associated infections in the early stage. Loading minocycline on the surface of implants based on LbL self-assembly strategy can endow implants with sustained antibacterial property. This can inhabit the immediate colonization of bacteria onto the surface of implants in the

  13. The in vivo biofilm

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Alhede, Maria; Alhede, Morten

    2013-01-01

    Bacteria can grow and proliferate either as single, independent cells or organized in aggregates commonly referred to as biofilms. When bacteria succeed in forming a biofilm within the human host, the infection often becomes very resistant to treatment and can develop into a chronic state. Biofilms...... have been studied for decades using various in vitro models, but it remains debatable whether such in vitro biofilms actually resemble in vivo biofilms in chronic infections. In vivo biofilms share several structural characteristics that differ from most in vitro biofilms. Additionally, the in vivo...... experimental time span and presence of host defenses differ from chronic infections and the chemical microenvironment of both in vivo and in vitro biofilms is seldom taken into account. In this review, we discuss why the current in vitro models of biofilms might be limited for describing infectious biofilms...

  14. Immune Modulating Topical S100A8/A9 Inhibits Growth of Pseudomonas aeruginosa and Mitigates Biofilm Infection in Chronic Wounds

    DEFF Research Database (Denmark)

    Trøstrup, Hannah; Lerche, Christian Johann; Christophersen, Lars

    2017-01-01

    in a murine model and P. aeruginosa growth in vitro. Seventy-six mice, inflicted with a full-thickness burn wound were challenged subcutaneously (s.c.) by 10⁶ colony-forming units (CFUs) of P. aeruginosa biofilm. Mice were subsequently randomized into two treatment groups, one group receiving recombinant...... murine S100A8/A9 and a group of vehicle controls (phosphate-buffered saline, PBS) all treated with s.c. injections daily for up to five days. Wounds were analyzed for quantitative bacteriology and contents of key inflammatory markers. Count of blood polymorphonuclear leukocytes was included. S100A8/A9...

  15. Biophysics of biofilm infection.

    Science.gov (United States)

    Stewart, Philip S

    2014-04-01

    This article examines a likely basis of the tenacity of biofilm infections that has received relatively little attention: the resistance of biofilms to mechanical clearance. One way that a biofilm infection persists is by withstanding the flow of fluid or other mechanical forces that work to wash or sweep microorganisms out of the body. The fundamental criterion for mechanical persistence is that the biofilm failure strength exceeds the external applied stress. Mechanical failure of the biofilm and release of planktonic microbial cells is also important in vivo because it can result in dissemination of infection. The fundamental criterion for detachment and dissemination is that the applied stress exceeds the biofilm failure strength. The apparent contradiction for a biofilm to both persist and disseminate is resolved by recognizing that biofilm material properties are inherently heterogeneous. There are also mechanical aspects to the ways that infectious biofilms evade leukocyte phagocytosis. The possibility of alternative therapies for treating biofilm infections that work by reducing biofilm cohesion could (1) allow prevailing hydrodynamic shear to remove biofilm, (2) increase the efficacy of designed interventions for removing biofilms, (3) enable phagocytic engulfment of softened biofilm aggregates, and (4) improve phagocyte mobility and access to biofilm. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  16. Anti-MRSA activities of Enterocins DD28 and DD93 and evidences on their role in the inhibition of biofilm formation

    Directory of Open Access Journals (Sweden)

    Ahmed Khassaf eAL ATYA

    2016-05-01

    Full Text Available Methicillin-resistant Staphylococcus aureus (MRSA, along with other antibiotic resistant bacteria, has become a worrisome superbug worldwide. This work was aimed at studying the efficacies of two class IIb bacteriocins, enterocins DD28 and DD93, against MRSA-S1 grown in planktonic culture and embedded in biofilms. These bacteriocins were purified, from the cultures supernatants of Enterococcus faecalis 28 and 93, using a simplified purification procedure consisting in a cation exchange chromatography and a reversed-phase high-performance liquid chromatography. The anti-Staphylococcal activity of these bacteriocins was shown in-vitro by the assessment of the minimal inhibitory concentration (MIC. Afterwhich, a checkerboard and time-kill kinetics permitted unveiled a synergistic effect of these bacteriocins in combination with erythromycin and kanamycin against the clinical MRSA-S1. These bacteriocins alone or in combination with erythromycin and kanamycin were able to impede the formation of MRSA-S1 biofilms on stainless steel and glace devices as supported by the microbial cell counts, epifluorescence and Scanning Electron Microscope analyses.

  17. A Nonbactericidal Zinc-Complexing Ligand as a Biofilm Inhibitor: Structure-Guided Contrasting Effects on Staphylococcus aureus Biofilm.

    Science.gov (United States)

    Kapoor, Vidushi; Rai, Rajanikant; Thiyagarajan, Durairaj; Mukherjee, Sandipan; Das, Gopal; Ramesh, Aiyagari

    2017-08-04

    Zinc-complexing ligands are prospective anti-biofilm agents because of the pivotal role of zinc in the formation of Staphylococcus aureus biofilm. Accordingly, the potential of a thiosemicarbazone (compound C1) and a benzothiazole-based ligand (compound C4) in the prevention of S. aureus biofilm formation was assessed. Compound C1 displayed a bimodal activity, hindering biofilm formation only at low concentrations and promoting biofilm growth at higher concentrations. In the case of C4, a dose-dependent inhibition of S. aureus biofilm growth was observed. Atomic force microscopy analysis suggested that at higher concentrations C1 formed globular aggregates, which perhaps formed a substratum that favored adhesion of cells and biofilm formation. In the case of C4, zinc supplementation experiments validated zinc complexation as a plausible mechanism of inhibition of S. aureus biofilm. Interestingly, C4 was nontoxic to cultured HeLa cells and thus has promise as a therapeutic anti-biofilm agent. The essential understanding of the structure-driven implications of zinc-complexing ligands acquired in this study might assist future screening regimes for identification of potent anti-biofilm agents. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Effect of biocides on biofilms of some multidrug resistant clinical ...

    African Journals Online (AJOL)

    The ability of Escherichia coli and Klebsiella aerogenes to form biofilms was most affected. There was little inhibition of biofilm formation by the biocides on Staphylococcus aureus. This study has shown a relationship between biocide and multidrug resistance. Keywords: Biocides, Multi drug resistance, sodium hypochlorite, ...

  19. Untersuchungen zur Erdbeerfruchtreifung : Biosynthese von 4-Hydroxy-2,5-dimethyl-3(2H)-furanon und Enzymaktivitäten während des Reifungsprozesses

    OpenAIRE

    Raab, Thomas

    2004-01-01

    Die Fruchtreifung stellt einen hochkomplexen Prozess dar, der durch eine Reihe von biochemischen und physiologischen Veränderungen gekennzeichnet ist. Dies umfasst bedeutende Veränderungen von Textur, Farbe sowie die Bildung von geschmacks- und geruchsaktiven Verbindungen. Die vorliegende Arbeit präsentiert neue Erkenntnisse zur Biosynthese von 4-Hydroxy-2,5-dimethyl-3(2H)-furanon (Furaneol®, HDMF), einer Schlüssel-Aromakomponente der Erdbeere (Fragaria x ananassa). Daneben lieferten die durc...

  20. Structural basis for the enzymatic formation of the key strawberry flavor compound 4-hydroxy-2,5-dimethyl-3(2H)-furanone.

    Science.gov (United States)

    Schiefner, André; Sinz, Quirin; Neumaier, Irmgard; Schwab, Wilfried; Skerra, Arne

    2013-06-07

    The last step in the biosynthetic route to the key strawberry flavor compound 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF) is catalyzed by Fragaria x ananassa enone oxidoreductase (FaEO), earlier putatively assigned as quinone oxidoreductase (FaQR). The ripening-induced enzyme catalyzes the reduction of the exocyclic double bond of the highly reactive precursor 4-hydroxy-5-methyl-2-methylene-3(2H)-furanone (HMMF) in a NAD(P)H-dependent manner. To elucidate the molecular mechanism of this peculiar reaction, we determined the crystal structure of FaEO in six different states or complexes at resolutions of ≤1.6 Å, including those with HDMF as well as three distinct substrate analogs. Our crystallographic analysis revealed a monomeric enzyme whose active site is largely determined by the bound NAD(P)H cofactor, which is embedded in a Rossmann-fold. Considering that the quasi-symmetric enolic reaction product HDMF is prone to extensive tautomerization, whereas its precursor HMMF is chemically labile in aqueous solution, we used the asymmetric and more stable surrogate product 2-ethyl-4-hydroxy-5-methyl-3(2H)-furanone (EHMF) and the corresponding substrate (2E)-ethylidene-4-hydroxy-5-methyl-3(2H)-furanone (EDHMF) to study their enzyme complexes as well. Together with deuterium-labeling experiments of EDHMF reduction by [4R-(2)H]NADH and chiral-phase analysis of the reaction product EHMF, our data show that the 4R-hydride of NAD(P)H is transferred to the unsaturated exocyclic C6 carbon of HMMF, resulting in a cyclic achiral enolate intermediate that subsequently becomes protonated, eventually leading to HDMF. Apart from elucidating this important reaction of the plant secondary metabolism our study provides a foundation for protein engineering of enone oxidoreductases and their application in biocatalytic processes.

  1. Biofilm Fixed Film Systems

    Directory of Open Access Journals (Sweden)

    Dipesh Das

    2011-09-01

    Full Text Available The work reviewed here was published between 2008 and 2010 and describes research that involved aerobic and anoxic biofilm treatment of water pollutants. Biofilm denitrification systems are covered when appropriate. References catalogued here are divided on the basis of fundamental research area or reactor types. Fundamental research into biofilms is presented in two sections, Biofilm Measurement and Characterization and Growth and Modeling. The reactor types covered are: trickling filters, rotating biological contactors, fluidized bed bioreactors, submerged bed biofilm reactors, biological granular activated carbon, membrane bioreactors, and immobilized cell reactors. Innovative reactors, not easily classified, are then presented, followed by a section on biofilms on sand, soil and sediment.

  2. Combined treatment of Pseudomonas aeruginosa biofilms with bacteriophages and chlorine.

    Science.gov (United States)

    Zhang, Yanyan; Hu, Zhiqiang

    2013-01-01

    Bacterial biofilms are a growing concern in a broad range of areas. In this study, a mixture of RNA bacteriophages isolated from municipal wastewater was used to control and remove biofilms. At the concentrations of 400 and 4 × 10(7) PFU/mL, the phages inhibited Pseudomonas aeruginosa biofilm formation by 45 ± 15% and 73 ± 8%, respectively. At the concentrations of 6,000 and 6 × 10(7) PFU/mL, the phages removed 45 ± 9% and 75 ± 5% of pre-existing P. aeruginosa biofilms, respectively. Chlorine reduced biofilm growth by 86 ± 3% at the concentration of 210 mg/L, but it did not remove pre-existing biofilms. However, a combination of phages (3 × 10(7) PFU/mL) and chlorine at this concentration reduced biofilm growth by 94 ± 2% and removed 88 ± 6% of existing biofilms. In a continuous flow system with continued biofilm growth, a combination of phages (a one-time treatment at the concentration of 1.9 × 10(8) PFU/mL for 1 h first) with chlorine removed 97 ± 1% of biofilms after Day 5 while phage and chlorine treatment alone removed 89 ± 1% and 40 ± 5%, respectively. For existing biofilms, a combined use of a lower phage concentration (3.8 × 10(5) PFU/mL) and chlorination with a shorter time duration (12 h) followed by continuous water flushing removed 96 ± 1% of biofilms in less than 2 days. Laser scanning confocal microscopy supplemented with electron microscopy indicated that the combination treatment resulted in biofilms with lowest cell density and viability. These results suggest that the combination treatment of phages and chlorine is a promising method to control and remove bacterial biofilms from various surfaces. Copyright © 2012 Wiley Periodicals, Inc.

  3. Pseudomonas aeruginosa Biofilm Infections

    DEFF Research Database (Denmark)

    Rybtke, Morten; Hultqvist, Louise Dahl; Givskov, Michael

    2015-01-01

    Studies of biopsies from infectious sites, explanted tissue and medical devises have provided evidence that biofilms are the underlying cause of a variety of tissue-associated and implant-associated recalcitrant human infections. With a need for novel anti-biofilm treatment strategies, research...... in biofilm infection microbiology, biofilm formation mechanisms and biofilm-associated antimicrobial tolerance has become an important area in microbiology. Substantial knowledge about biofilm formation mechanisms, biofilm-associated antimicrobial tolerance and immune evasion mechanisms has been obtained...... through work with biofilms grown in in vitro experimental setups, and the relevance of this information in the context of chronic infections is being investigated by the use of animal models of infection. Because our current in vitro experimental setups and animal models have limitations, new advanced...

  4. Biofilm Formation As a Response to Ecological Competition.

    Directory of Open Access Journals (Sweden)

    Nuno M Oliveira

    2015-07-01

    Full Text Available Bacteria form dense surface-associated communities known as biofilms that are central to their persistence and how they affect us. Biofilm formation is commonly viewed as a cooperative enterprise, where strains and species work together for a common goal. Here we explore an alternative model: biofilm formation is a response to ecological competition. We co-cultured a diverse collection of natural isolates of the opportunistic pathogen Pseudomonas aeruginosa and studied the effect on biofilm formation. We show that strain mixing reliably increases biofilm formation compared to unmixed conditions. Importantly, strain mixing leads to strong competition: one strain dominates and largely excludes the other from the biofilm. Furthermore, we show that pyocins, narrow-spectrum antibiotics made by other P. aeruginosa strains, can stimulate biofilm formation by increasing the attachment of cells. Side-by-side comparisons using microfluidic assays suggest that the increase in biofilm occurs due to a general response to cellular damage: a comparable biofilm response occurs for pyocins that disrupt membranes as for commercial antibiotics that damage DNA, inhibit protein synthesis or transcription. Our data show that bacteria increase biofilm formation in response to ecological competition that is detected by antibiotic stress. This is inconsistent with the idea that sub-lethal concentrations of antibiotics are cooperative signals that coordinate microbial communities, as is often concluded. Instead, our work is consistent with competition sensing where low-levels of antibiotics are used to detect and respond to the competing genotypes that produce them.

  5. Anti-Biofilm Compounds Derived from Marine Sponges

    Directory of Open Access Journals (Sweden)

    Christian Melander

    2011-10-01

    Full Text Available Bacterial biofilms are surface-attached communities of microorganisms that are protected by an extracellular matrix of biomolecules. In the biofilm state, bacteria are significantly more resistant to external assault, including attack by antibiotics. In their native environment, bacterial biofilms underpin costly biofouling that wreaks havoc on shipping, utilities, and offshore industry. Within a host environment, they are insensitive to antiseptics and basic host immune responses. It is estimated that up to 80% of all microbial infections are biofilm-based. Biofilm infections of indwelling medical devices are of particular concern, since once the device is colonized, infection is almost impossible to eliminate. Given the prominence of biofilms in infectious diseases, there is a notable effort towards developing small, synthetically available molecules that will modulate bacterial biofilm development and maintenance. Here, we highlight the development of small molecules that inhibit and/or disperse bacterial biofilms specifically through non-microbicidal mechanisms. Importantly, we discuss several sets of compounds derived from marine sponges that we are developing in our labs to address the persistent biofilm problem. We will discuss: discovery/synthesis of natural products and their analogues—including our marine sponge-derived compounds and initial adjuvant activity and toxicological screening of our novel anti-biofilm compounds.

  6. Identification of anti-biofilm components in Withania somnifera and their effect on virulence of Streptococcus mutans biofilms.

    Science.gov (United States)

    Pandit, S; Cai, J N; Song, K Y; Jeon, J G

    2015-08-01

    The aim of this study was to identify components of the Withania somnifera that could show anti-virulence activity against Streptococcus mutans biofilms. The anti-acidogenic activity of fractions separated from W. somnifera was compared, and then the most active anti-acidogenic fraction was chemically characterized using gas chromatography-mass spectroscopy. The effect of the identified components on the acidogenicity, aciduricity and extracellular polymeric substances (EPS) formation of S. mutans UA159 biofilms was evaluated. The change in accumulation and acidogenicity of S. mutans UA159 biofilms by periodic treatments (10 min per treatment) with the identified components was also investigated. Of the fractions, n-hexane fraction showed the strongest anti-acidogenic activity and was mainly composed of palmitic, linoleic and oleic acids. Of the identified components, linoleic and oleic acids strongly affected the acid production rate, F-ATPase activity and EPS formation of the biofilms. Periodic treatment with linoleic and oleic acids during biofilm formation also inhibited the biofilm accumulation and acid production rate of the biofilms without killing the biofilm bacteria. These results suggest that linoleic and oleic acids may be effective agents for restraining virulence of S. mutans biofilms. Linoleic and oleic acids may be promising agents for controlling virulence of cariogenic biofilms and subsequent dental caries formation. © 2015 The Society for Applied Microbiology.

  7. The Biofilm Challenge

    DEFF Research Database (Denmark)

    Alhede, Maria; Alhede, Morten

    2014-01-01

    The concept of biofilms has emerged in the clinical setting during the last decade. Infections involving biofilms have been documented in all parts of the human body, and it is currently believed that the presence of biofilm-forming bacteria is equivalent to chronic infection. A quick Pubmed search...

  8. Design, synthesis, and in vitro antituberculosis activity of 2(5H)-Furanone derivatives

    CSIR Research Space (South Africa)

    Ngwane, AH

    2016-01-01

    Full Text Available growth (Bioscreen C system). In screening the active first-generation compounds for growth inhibition against Mycobacterium tuberculosis H37Rv, the most active compound was identified with a minimum inhibitory concentration (MIC99 ) of 8.07 µg/mL (15.8 µ...

  9. In vitro characterization of biofilms formed by Kingella kingae.

    Science.gov (United States)

    Kaplan, J B; Sampathkumar, V; Bendaoud, M; Giannakakis, A K; Lally, E T; Balashova, N V

    2017-08-01

    The Gram-negative bacterium Kingella kingae is part of the normal oropharyngeal mucosal flora of children biofilm formation has been coupled with pharyngeal colonization, osteoarticular infections, and infective endocarditis, no studies have investigated biofilm formation in K. kingae. In this study we measured biofilm formation by 79 K. kingae clinical isolates using a 96-well microtiter plate crystal violet binding assay. We found that 37 of 79 strains (47%) formed biofilms. All strains that formed biofilms produced corroding colonies on agar. Biofilm formation was inhibited by proteinase K and DNase I. DNase I also caused the detachment of pre-formed K. kingae biofilm colonies. A mutant strain carrying a deletion of the pilus gene cluster pilA1pilA2fimB did not produce corroding colonies on agar, autoaggregate in broth, or form biofilms. Biofilm forming strains have higher levels of pilA1 expression. The extracellular components of biofilms contained 490 μg cm -2 of protein, 0.68 μg cm -2 of DNA, and 0.4 μg cm -2 of total carbohydrates. We concluded that biofilm formation is common among K. kingae clinical isolates, and that biofilm formation is dependent on the production of proteinaceous pili and extracellular DNA. Biofilm development may have relevance to the colonization, transmission, and pathogenesis of this bacterium. Extracellular DNA production by K. kingae may facilitate horizontal gene transfer within the oral microbial community. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. Strategies for combating bacterial biofilms: A focus on anti-biofilm agents and their mechanisms of action

    Science.gov (United States)

    Roy, Ranita; Tiwari, Monalisa; Donelli, Gianfranco; Tiwari, Vishvanath

    2018-01-01

    ABSTRACT Biofilm refers to the complex, sessile communities of microbes found either attached to a surface or buried firmly in an extracellular matrix as aggregates. The biofilm matrix surrounding bacteria makes them tolerant to harsh conditions and resistant to antibacterial treatments. Moreover, the biofilms are responsible for causing a broad range of chronic diseases and due to the emergence of antibiotic resistance in bacteria it has really become difficult to treat them with efficacy. Furthermore, the antibiotics available till date are ineffective for treating these biofilm related infections due to their higher values of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), which may result in in-vivo toxicity. Hence, it is critically important to design or screen anti-biofilm molecules that can effectively minimize and eradicate biofilm related infections. In the present article, we have highlighted the mechanism of biofilm formation with reference to different models and various methods used for biofilm detection. A major focus has been put on various anti-biofilm molecules discovered or tested till date which may include herbal active compounds, chelating agents, peptide antibiotics, lantibiotics and synthetic chemical compounds along with their structures, mechanism of action and their respective MICs, MBCs, minimum biofilm inhibitory concentrations (MBICs) as well as the half maximal inhibitory concentration (IC50) values available in the literature so far. Different mode of action of anti biofilm molecules addressed here are inhibition via interference in the quorum sensing pathways, adhesion mechanism, disruption of extracellular DNA, protein, lipopolysaccharides, exopolysaccharides and secondary messengers involved in various signaling pathways. From this study, we conclude that the molecules considered here might be used to treat biofilm-associated infections after significant structural modifications, thereby

  11. Wild Mushroom Extracts as Inhibitors of Bacterial Biofilm Formation

    Directory of Open Access Journals (Sweden)

    Maria José Alves

    2014-08-01

    Full Text Available Microorganisms can colonize a wide variety of medical devices, putting patients in risk for local and systemic infectious complications, including local-site infections, catheter-related bloodstream infections, and endocarditis. These microorganisms are able to grow adhered to almost every surface, forming architecturally complex communities termed biofilms. The use of natural products has been extremely successful in the discovery of new medicine, and mushrooms could be a source of natural antimicrobials. The present study reports the capacity of wild mushroom extracts to inhibit in vitro biofilm formation by multi-resistant bacteria. Four Gram-negative bacteria biofilm producers (Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, and Acinetobacter baumannii isolated from urine were used to verify the activity of Russula delica, Fistulina hepatica, Mycena rosea, Leucopaxilus giganteus, and Lepista nuda extracts. The results obtained showed that all tested mushroom extracts presented some extent of inhibition of biofilm production. Pseudomonas aeruginosa was the microorganism with the highest capacity of biofilm production, being also the most susceptible to the extracts inhibition capacity (equal or higher than 50%. Among the five tested extracts against E. coli, Leucopaxillus giganteus (47.8% and Mycenas rosea (44.8% presented the highest inhibition of biofilm formation. The extracts exhibiting the highest inhibitory effect upon P. mirabilis biofilm formation were Sarcodon imbricatus (45.4% and Russula delica (53.1%. Acinetobacter baumannii was the microorganism with the lowest susceptibility to mushroom extracts inhibitory effect on biofilm production (highest inhibition—almost 29%, by Russula delica extract. This is a pioneer study since, as far as we know, there are no reports on the inhibition of biofilm production by the studied mushroom extracts and in particular against multi-resistant clinical isolates; nevertheless, other

  12. Proteins with GGDEF and EAL domains regulate Pseudomonas putida biofilm formation and dispersal

    DEFF Research Database (Denmark)

    Gjermansen, Morten; Ragas, Paula Cornelia; Tolker-Nielsen, Tim

    2006-01-01

    Microbial biofilm formation often causes problems in medical and industrial settings, and knowledge about the factors that are involved in biofilm development and dispersion is useful for creating strategies to control the processes. In this report, we present evidence that proteins with GGDEF...... and EAL domains are involved in the regulation of biofilm formation and biofilm dispersion in Pseudomonas putida. Overexpression in P. putida of the Escherichia coli YedQ protein, which contains a GGDEF domain, resulted in increased biofilm formation. Overexpression in P. putida of the E. coli Yhj......H protein, which contains an EAL domain, strongly inhibited biofilm formation. Induction of YhjH expression in P. putida cells situated in established biofilms led to rapid dispersion of the biofilms. These results support the emerging theme that GGDEF-domain and EAL-domain proteins are involved...

  13. [The effect of biyuanshu oral liquid on the formation of Pseudomonas aeruginosa biofilms in vitro].

    Science.gov (United States)

    Liu, Xiang; Chen, Haihong; Wang, Shengqing

    2012-07-01

    To observe the effect of biyuanshu oral liquid on the formation of pseudomonas aeruginosa biofilms in vitro. Pseudomonas aeruginosa biofilm was established by plate culture and detected by Scanning electron microscopy and AgNO3 staining. After treated with different dosages of biyuanshu oral liquid and erythromycin, the pseudomonas aeruginosa biofilms were observed by AgNO3 staining and the number of viable bacteria were measured by serial dilution. The pseudomonas aeruginosa biofilms could be detected by SEM at the seventh culture day and it was consistent with the detection of AgNO3 staining. The biyuanshu oral liquid and erythromycin have the effect on inhibiting the formation of pseudomonas aeruginosa biofilms. But with the already formed pseudomonas aeruginosa biofilms the inhibition was not significant. The serial dilution method showed that the viable counts of bacteria of biyuanshu oral liquid and erythromycin treated groups were significantly lower than those untreated groups (P formation of pseudomonas aeruginosa biofilms in vitro.

  14. Probiotic Lactobacillus reuteri biofilms produce antimicrobial and anti-inflammatory factors

    Directory of Open Access Journals (Sweden)

    Jones Sara E

    2009-02-01

    Full Text Available Abstract Background Commensal-derived probiotic bacteria inhibit enteric pathogens and regulate host immune responses in the gastrointestinal tract, but studies examining specific functions of beneficial microbes in the context of biofilms have been limited in scope. Results Lactobacillus reuteri formed biofilms that retained functions potentially advantageous to the host including modulation of cytokine output and the production of the antimicrobial agent, reuterin. Immunomodulatory activities of biofilms were demonstrated by the abilities of specific L. reuteri strains to suppress human TNF production by LPS-activated monocytoid cells. Quantification of the antimicrobial glycerol derivative, reuterin, was assessed in order to document the antipathogenic potential of probiotic biofilms. L. reuteri biofilms differed in the quantities of reuterin secreted in this physiological state. Conclusion L. reuteri biofilms secreted factors that confer specific health benefits such as immunomodulation and pathogen inhibition. Future probiotic selection strategies should consider a strain's ability to perform beneficial functions as a biofilm.

  15. Role of bacterial efflux pumps in biofilm formation.

    Science.gov (United States)

    Alav, Ilyas; Sutton, J Mark; Rahman, Khondaker Miraz

    2018-02-28

    Efflux pumps are widely implicated in antibiotic resistance because they can extrude the majority of clinically relevant antibiotics from within cells to the extracellular environment. However, there is increasing evidence from many studies to suggest that the pumps also play a role in biofilm formation. These studies have involved investigating the effects of efflux pump gene mutagenesis and efflux pump inhibitors on biofilm formation, and measuring the levels of efflux pump gene expression in biofilms. In particular, several key pathogenic species associated with increasing multidrug resistance, such as Acinetobacter baumannii, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus, have been investigated, whilst other studies have focused on Salmonella enterica serovar Typhimurium as a model organism and problematic pathogen. Studies have shown that efflux pumps, including AcrAB-TolC of E. coli, MexAB-OprM of P. aeruginosa, AdeFGH of A. baumannii and AcrD of S. enterica, play important roles in biofilm formation. The substrates for such pumps, and whether changes in their efflux activity affect biofilm formation directly or indirectly, remain to be determined. By understanding the roles that efflux pumps play in biofilm formation, novel therapeutic strategies can be developed to inhibit their function, to help disrupt biofilms and improve the treatment of infections. This review will discuss and evaluate the evidence for the roles of efflux pumps in biofilm formation and the potential approaches to overcome the increasing problem of biofilm-based infections.

  16. Strawberry Extract’s Effects on Enterococcus faecalis and Porphyromonas gingivalis Biofilms in vitro

    Directory of Open Access Journals (Sweden)

    Armelia Sari Widyarman

    2017-09-01

    Full Text Available Background: Enterococcus faecalis (E. faecalis and Porphyromonas gingivalis (P. gingivalis are oral bacteria related to root canal infection and periodontal disease pathogenesis. Strawberries (Fragaria x ananassa fruit are rich in vitamins and minerals, have antibacterial and antioxidant effects. Objective: This study investigated the inhibition effect of strawberry extract on monospecies and multispecies E. faecalis and P. gingivalis bacteria grown as biofilms in vitro. Methods: This study used E. faecalis ATCC 29212 and P. gingivalis ATCC 33277. It analyzed the effect of strawberry extract on bacteria biofilm formation using a biofilm assay on microplate wells. Five concentrations of strawberry extracts were used (100%, 50%, 25%, 12.5%, and 6.25%, and the inhibition effect was observed after a 1h, 3h, 6h, and 24h incubation period. Biofilms without the strawberry extract were used as the negative controls, and crystal violet and safranin (0.5%w/v were used to count the biofilm mass. The biofilms grown on microplates were counted using an ELISA reader at 450 nm after 200 mL of 90% ethanol was added to attract the absorbed stain. The strawberry extract inhibition effectiveness on the biofilm formation of each bacterium tested was analyzed using one-way Anova, where p<0.05 was defined as a significant difference. Result: The strawberry extract inhibited the tested monospecies and multispecies bacteria biofilm formation. The optimal strawberry extract concentration for the inhibition of either monospecies biofilms was 100%. However, the optimal incubation time for the strawberry extract to inhibit the multispecies biofilm formation was 24h, which was the study’s biofilm maturity phase. Conclusions: The 100% strawberry extract concentration inhibited the formation of both the monospecies and multispecies E. faecalis and P. gingivalis biofilms. Future studies are needed to evaluate the potential of strawberry extract as an alternative dental

  17. Intrinsic and Extrinsic Aspects on Campylobacter jejuni Biofilms

    Directory of Open Access Journals (Sweden)

    Roberta T. Melo

    2017-07-01

    Full Text Available Biofilm represents a way of life that allows greater survival of microorganisms in hostile habitats. Campylobacter jejuni is able to form biofilms in vitro and on surfaces at several points in the poultry production chain. Genetic determinants related to their formation are expressed differently between strains and external conditions are decisive in this respect. Our approach combines phylogenetic analysis and the presence of seven specific genes linked to biofilm formation in association with traditional microbiology techniques, using Mueller Hinton and chicken juice as substrates in order to quantify, classify, determine the composition and morphology of the biomass of simple and mixed biofilms of 30 C. jejuni strains. It also evaluates the inhibition of its formation by biocides commonly used in industry and also by zinc oxide nanoparticles. Genetic analysis showed high heterogeneity with the identification of 23 pulsotypes. Despite the diversity, the presence of flaA, cadF, luxS, dnaJ, htrA, cbrA, and sodB genes in all strains shows the high potential for biofilm formation. This ability was only expressed in chicken juice, where they presented phenotype of a strong biofilm producer, with a mean count of 7.37 log CFU/mL and an ultrastructure characteristic of mature biofilm. The composition of simple and mixed biofilms was predominantly composed by proteins. The exceptions were found in mixed biofilms with Pseudomonas aeruginosa, which includes a carbohydrate-rich matrix, lower ability to sessile form in chicken juice and compact architecture of the biofilm, this aspects are intrinsic to this species. Hypochlorite, chlorhexidine, and peracetic acid were more effective in controlling viable cells of C. jejuni in biofilm, but the existence of tolerant strains indicates exposure to sublethal concentrations and development of adaptation mechanisms. This study shows that in chicken juice C. jejuni presents greater potential in producing mature

  18. FaQR, required for the biosynthesis of the strawberry flavor compound 4-hydroxy-2,5-dimethyl-3(2H)-furanone, encodes an enone oxidoreductase.

    Science.gov (United States)

    Raab, Thomas; López-Ráez, Juan Antonio; Klein, Dorothée; Caballero, Jose Luis; Moyano, Enriqueta; Schwab, Wilfried; Muñoz-Blanco, Juan

    2006-04-01

    The flavor of strawberry (Fragaria x ananassa) fruit is dominated by an uncommon group of aroma compounds with a 2,5-dimethyl-3(H)-furanone structure. We report the characterization of an enzyme involved in the biosynthesis of 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF; Furaneol), the key flavor compound in strawberries. Protein extracts were partially purified, and the observed distribution of enzymatic activity correlated with the presence of a single polypeptide of approximately 37 kD. Sequence analysis of two peptide fragments showed total identity with the protein sequence of a strongly ripening-induced, auxin-dependent putative quinone oxidoreductase, Fragaria x ananassa quinone oxidoreductase (FaQR). The open reading frame of the FaQR cDNA consists of 969 bp encoding a 322-amino acid protein with a calculated molecular mass of 34.3 kD. Laser capture microdissection followed by RNA extraction and amplification demonstrated the presence of FaQR mRNA in parenchyma tissue of the strawberry fruit. The FaQR protein was functionally expressed in Escherichia coli, and the monomer catalyzed the formation of HDMF. After chemical synthesis and liquid chromatography-tandem mass spectrometry analysis, 4-hydroxy-5-methyl-2-methylene-3(2H)-furanone was confirmed as a substrate of FaQR and the natural precursor of HDMF. This study demonstrates the function of the FaQR enzyme in the biosynthesis of HDMF as enone oxidoreductase and provides a foundation for the improvement of strawberry flavor and the biotechnological production of HDMF.

  19. Biofilm formation in long-term central venous catheters in children with cancer

    DEFF Research Database (Denmark)

    Handrup, Mette Møller; Fuursted, Kurt; Funch, Peter

    2012-01-01

    Taurolidine has demonstrated inhibition of biofilm formation in vitro. The aim of this study was to compare the effect of catheter locking with taurolidine vs heparin in biofilm formation in central venous catheters. Forty-eight children with cancer were randomized to catheter locking by heparin (n...... = 22) or taurolidine (n = 26), respectively. After removal, catheters were examined by standardized scanning electron microscopy to assess quantitative biofilm formation. Biofilm was present if morphologically typical structures and bacterial cells were identified. Quantitative and semi...... in the intraluminal biofilm formation and the rate of bacterial colonization detected by scanning electron microscopy in the two groups....

  20. Inhibition of quorum sensing and biofilm formation in Vibrio harveyi by 4-fluoro-DPD; a novel potent inhibitor of signalling.

    Science.gov (United States)

    Kadirvel, Manikandan; Fanimarvasti, Fariba; Forbes, Sarah; McBain, Andrew; Gardiner, John M; Brown, Gavin D; Freeman, Sally

    2014-05-21

    (S)-4,5-Dihydroxypentane-2,3-dione [(S)-DPD, (1)] is a precursor for , a quorum sensing signalling molecule for inter- and intra-species bacterial communication. The synthesis of its fluoro-analogue, 4-fluoro-5-hydroxypentane-2,3-dione () is reported. An intermediate in this route also enables a new, shorter synthesis of the native (S)-DPD. 4-Fluoro-DPD (2) completely inhibited bioluminescence and bacterial growth of Vibrio harveyi BB170 strain at 12.5 μM and 100 μM, respectively.

  1. Pseudomonas aeruginosa biofilm infections

    DEFF Research Database (Denmark)

    Tolker-Nielsen, Tim

    2014-01-01

    Bacteria in natural, industrial and clinical settings predominantly live in biofilms, i.e., sessile structured microbial communities encased in self-produced extracellular matrix material. One of the most important characteristics of microbial biofilms is that the resident bacteria display...... a remarkable increased tolerance toward antimicrobial attack. Biofilms formed by opportunistic pathogenic bacteria are involved in devastating persistent medical device-associated infections, and chronic infections in individuals who are immune-compromised or otherwise impaired in the host defense. Because...... the use of conventional antimicrobial compounds in many cases cannot eradicate biofilms, there is an urgent need to develop alternative measures to combat biofilm infections. The present review is focussed on the important opportunistic pathogen and biofilm model organism Pseudomonas aeruginosa. Initially...

  2. Mathematical Modeling of Biofilm Structures Using COMSTAT Data

    DEFF Research Database (Denmark)

    Verotta, Davide; Haagensen, Janus Anders Juul; Spormann, Alfred M.

    2017-01-01

    Mathematical modeling holds great potential for quantitatively describing biofilm growth in presence or absence of chemical agents used to limit or promote biofilm growth. In this paper, we describe a general mathematical/statistical framework that allows for the characterization of complex data...... in terms of few parameters and the capability to (i) compare different experiments and exposures to different agents, (ii) test different hypotheses regarding biofilm growth and interaction with different agents, and (iii) simulate arbitrary administrations of agents. The mathematical framework is divided...... to submodels characterizing biofilm, including new models characterizing live biofilm growth and dead cell accumulation; the interaction with agents inhibiting or stimulating growth; the kinetics of the agents. The statistical framework can take into account measurement and interexperiment variation. We...

  3. Mathematical Modeling of Biofilm Structures Using COMSTAT Data

    Directory of Open Access Journals (Sweden)

    Davide Verotta

    2017-01-01

    Full Text Available Mathematical modeling holds great potential for quantitatively describing biofilm growth in presence or absence of chemical agents used to limit or promote biofilm growth. In this paper, we describe a general mathematical/statistical framework that allows for the characterization of complex data in terms of few parameters and the capability to (i compare different experiments and exposures to different agents, (ii test different hypotheses regarding biofilm growth and interaction with different agents, and (iii simulate arbitrary administrations of agents. The mathematical framework is divided to submodels characterizing biofilm, including new models characterizing live biofilm growth and dead cell accumulation; the interaction with agents inhibiting or stimulating growth; the kinetics of the agents. The statistical framework can take into account measurement and interexperiment variation. We demonstrate the application of (some of the models using confocal microscopy data obtained using the computer program COMSTAT.

  4. Effects of ginseng on Pseudomonas aeruginosa motility and biofilm formation

    DEFF Research Database (Denmark)

    Wu, Hong; Lee, Baoleri; Yang, Liang

    2011-01-01

    protected animal models from developing chronic lung infection by P. aeruginosa. In the present study, the effects of ginseng on the formation of P. aeruginosa biofilms were further investigated in vitro and in vivo. Ginseng aqueous extract at concentrations of 0.5-2.0% did not inhibit the growth of P......Biofilm-associated chronic Pseudomonas aeruginosa lung infections in patients with cystic fibrosis are virtually impossible to eradicate with antibiotics because biofilm-growing bacteria are highly tolerant to antibiotics and host defense mechanisms. Previously, we found that ginseng treatments....... aeruginosa, but significantly prevented P. aeruginosa from forming biofilm. Exposure to 0.5% ginseng aqueous extract for 24 h destroyed most 7-day-old mature biofilms formed by both mucoid and nonmucoid P. aeruginosa strains. Ginseng treatment enhanced swimming and twitching motility, but reduced swarming...

  5. Analysis of hyper-baric biofilms on engineering surfaces formed in the Deep Sea

    Science.gov (United States)

    Meier, A.; Tsaloglou, N. M.; Connelly, D.; Keevil, B.; Mowlem, M.

    2012-04-01

    coverage on copper and PMMA was a third of that on Delrin™ and less than half the amount seen on glass surfaces. PCR showed that the microorganisms in these biofilms were predominantly Archea . DGGE conditions were optimised for the separation of PCR products from the three kingdoms. Sequencing data is still being processed. These results show that mitigation strategies are essential for any kind of long-term deployments of remote sensors even in the deep sea. Such strategies could consist for example of chlorine production through the electrolysis of seawater, back-flushing sensor channels with various chemicals, thin films of nickel/copper/zinc alloys in various ratios as surface treatments, quorum-sensing, furanone-treatment and micro-structuring of surfaces.

  6. Resistance of biofilm-covered mortars to microbiologically influenced deterioration simulated by sulfuric acid exposure

    Energy Technology Data Exchange (ETDEWEB)

    Soleimani, Sahar, E-mail: ssoleima@connect.carleton.ca; Isgor, O. Burkan, E-mail: burkan_isgor@carleton.ca; Ormeci, Banu, E-mail: banu_ormeci@carleton.ca

    2013-11-15

    Following the reported success of biofilm applications on metal surfaces to inhibit microbiologically influenced corrosion, effectiveness and sustainability of E. coli DH5α biofilm on mortar surface to prevent microbiologically influenced concrete deterioration (MICD) are investigated. Experiments simulating microbial attack were carried out by exposing incrementally biofilm-covered mortar specimens to sulfuric acid solutions with pH ranging from 3 to 6. Results showed that calcium concentration in control reactors without biofilm was 23–47% higher than the reactors with biofilm-covered mortar. Formation of amorphous silica gel as an indication of early stages of acid attack was observed only on the control mortar specimens without biofilm. During acidification, the biofilm continued to grow and its thickness almost doubled from ∼ 30 μm before acidification to ∼ 60 μm after acidification. These results demonstrated that E. coli DH5α biofilm was able to provide a protective and sustainable barrier on mortar surfaces against medium to strong sulfuric acid attack. -- Highlights: •Effectiveness of E.coli DH5α biofilm to prevent MICD was studied. •Conditions that lead to MICD were simulated by chemical acidification. •Biofilm-covered mortar specimens were exposed to sulfuric acid solutions. •The presence of biofilm helped reduce the chemically-induced mortar deterioration. •Biofilm remained alive and continued to grow during the acidification process.

  7. Resistance of biofilm-covered mortars to microbiologically influenced deterioration simulated by sulfuric acid exposure

    International Nuclear Information System (INIS)

    Soleimani, Sahar; Isgor, O. Burkan; Ormeci, Banu

    2013-01-01

    Following the reported success of biofilm applications on metal surfaces to inhibit microbiologically influenced corrosion, effectiveness and sustainability of E. coli DH5α biofilm on mortar surface to prevent microbiologically influenced concrete deterioration (MICD) are investigated. Experiments simulating microbial attack were carried out by exposing incrementally biofilm-covered mortar specimens to sulfuric acid solutions with pH ranging from 3 to 6. Results showed that calcium concentration in control reactors without biofilm was 23–47% higher than the reactors with biofilm-covered mortar. Formation of amorphous silica gel as an indication of early stages of acid attack was observed only on the control mortar specimens without biofilm. During acidification, the biofilm continued to grow and its thickness almost doubled from ∼ 30 μm before acidification to ∼ 60 μm after acidification. These results demonstrated that E. coli DH5α biofilm was able to provide a protective and sustainable barrier on mortar surfaces against medium to strong sulfuric acid attack. -- Highlights: •Effectiveness of E.coli DH5α biofilm to prevent MICD was studied. •Conditions that lead to MICD were simulated by chemical acidification. •Biofilm-covered mortar specimens were exposed to sulfuric acid solutions. •The presence of biofilm helped reduce the chemically-induced mortar deterioration. •Biofilm remained alive and continued to grow during the acidification process

  8. The Fluid Dynamics of Nascent Biofilms

    Science.gov (United States)

    Farthing, Nicola; Snow, Ben; Wilson, Laurence; Bees, Martin

    2017-11-01

    Many anti-biofilm approaches target mature biofilms with biochemical or physio-chemical interventions. We investigate the mechanics of interventions at an early stage that aim to inhibit biofilm maturation, focusing on hydrodynamics as cells transition from planktonic to surface-attached. Surface-attached cells generate flow fields that are relatively long-range compared with cells that are freely-swimming. We look at the effect of these flows on the biofilm formation. In particular, we use digital inline holographic microscopy to determine the three-dimensional flow due to a surface-attached cell and the effect this flow has on both tracers and other cells in the fluid. We compare experimental data with two models of cells on boundaries. The first approach utilizes slender body theory and captures many of the features of the experimental field. The second model develops a simple description in terms of singularity solutions of Stokes' flow, which produces qualitatively similar dynamics to both the experiments and more complex model but with significant computational savings. The range of validity of multiple cell arrangements is investigated. These two descriptions can be used to investigate the efficacy of actives developed by Unilever on nascent biofilms.

  9. In vivo evaluation of an antibacterial coating containing halogenated furanone compound-loaded poly(l-lactic acid) nanoparticles on microarc-oxidized titanium implants.

    Science.gov (United States)

    Cheng, Yicheng; Gao, Bo; Liu, Xianghui; Zhao, Xianghui; Sun, Weige; Ren, Huifang; Wu, Jiang

    2016-01-01

    To prevent peri-implant infection, a new antibacterial coating containing a halogenated furanone compound, (Z-)-4-bromo-5-(bromomethylene)-2(5H)-furanone-loaded poly(l-lactic acid) nanoparticles, has been fabricated. The current study was designed to evaluate the preventive effect of the antibacterial coating under a simulated environment of peri-implant infection in vivo. Microarc-oxidized titanium implants treated with minocycline hydrochloride ointment were used as positive control group, and microarc-oxidized titanium implants without any treatment were used as blank control group. Three kinds of implants were implanted in dogs' mandibles, and the peri-implant infection was simulated by silk ligation and feeding high sugar diet. After 2-month implantation, the results showed that no significant differences were detected between the experimental and positive control groups (P>0.05), but the data of clinical measurements of the blank control group were significantly higher than those of the other two groups (Pmicroscope observation and histological examination showed that more new bone was formed on the surface of the experimental and positive control groups. It can be concluded that the antibacterial coating fabricated on implants has remarkable preventive effect on peri-implant infection at the early stage.

  10. Biofilm Formation of Staphylococcus aureus on Various Surfaces and Their Resistance to Chlorine Sanitizer.

    Science.gov (United States)

    Lee, Jung-Su; Bae, Young-Min; Lee, Sook-Young; Lee, Sun-Young

    2015-10-01

    This study investigated the effect of material types (polystyrene, polypropylene, glass, and stainless steel) and glucose addition on Staphylococcus aureus biofilm formation, and the relationship between biofilm formation measured by crystal violet (CV) staining and the number of biofilm cells determined by cell counts was studied. We also evaluated the efficacy of chlorine sanitizer on inhibiting various different types of S. aureus biofilms on the surface of stainless steel. Levels of biofilm formation of S. aureus were higher on hydrophilic surfaces (glass and stainless steel) than on hydrophobic surfaces (polypropylene and polystyrene). With the exception of biofilm formed on glass, the addition of glucose in broth significantly increased the biofilm formation of S. aureus on all surfaces and for all tested strains (P ≤ 0.05). The number of biofilm cells was not correlated with the biomass of the biofilms determined using the CV staining method. The efficacy of chlorine sanitizer against biofilm of S. aureus was not significantly different depending on types of biofilm (P > 0.05). Therefore, further studies are needed in order to determine an accurate method quantifying levels of bacterial biofilm and to evaluate the resistance of bacterial biofilm on the material surface. Biofilm formation of Staphylococcus aureus on the surface was different depending on the surface characteristics and S. aureus strains. There was low correlation between crystal violet staining method and viable counts technique for measuring levels of biofilm formation of S. aureus on the surfaces. These results could provide helpful information for finding and understanding the quantification method and resistance of bacterial biofilm on the surface. © 2015 Institute of Food Technologists®

  11. Hydraulic resistance of biofilms

    KAUST Repository

    Dreszer, C.

    2013-02-01

    Biofilms may interfere with membrane performance in at least three ways: (i) increase of the transmembrane pressure drop, (ii) increase of feed channel (feed-concentrate) pressure drop, and (iii) increase of transmembrane passage. Given the relevance of biofouling, it is surprising how few data exist about the hydraulic resistance of biofilms that may affect the transmembrane pressure drop and membrane passage. In this study, biofilms were generated in a lab scale cross flow microfiltration system at two fluxes (20 and 100Lm-2h-1) and constant cross flow (0.1ms-1). As a nutrient source, acetate was added (1.0mgL-1 acetate C) besides a control without nutrient supply. A microfiltration (MF) membrane was chosen because the MF membrane resistance is very low compared to the expected biofilm resistance and, thus, biofilm resistance can be determined accurately. Transmembrane pressure drop was monitored. As biofilm parameters, thickness, total cell number, TOC, and extracellular polymeric substances (EPS) were determined, it was demonstrated that no internal membrane fouling occurred and that the fouling layer actually consisted of a grown biofilm and was not a filter cake of accumulated bacterial cells. At 20Lm-2h-1 flux with a nutrient dosage of 1mgL-1 acetate C, the resistance after 4 days reached a value of 6×1012m-1. At 100Lm-2h-1 flux under the same conditions, the resistance was 5×1013m-1. No correlation of biofilm resistance to biofilm thickness was found; Biofilms with similar thickness could have different resistance depending on the applied flux. The cell number in biofilms was between 4×107 and 5×108 cellscm-2. At this number, bacterial cells make up less than a half percent of the overall biofilm volume and therefore did not hamper the water flow through the biofilm significantly. A flux of 100Lm-2h-1 with nutrient supply caused higher cell numbers, more biomass, and higher biofilm resistance than a flux of 20Lm-2h-1. However, the biofilm thickness

  12. Bioactive Compounds Produced by Hypoxylon fragiforme against Staphylococcus aureus Biofilms

    Directory of Open Access Journals (Sweden)

    Kamila Tomoko Yuyama

    2017-12-01

    Full Text Available Treating infections organized in biofilms is a challenge due to the resistance of the pathogens against antibiotics and host immune cells. Many fungi grow in a wet environment, favorable for the growth of bacterial biofilms, and we speculated that fungi possess some strategies to control these bacterial biofilms. A fungus identified as Hypoxylon fragiforme, was collected in the Harz Mountains, Germany, and its mycelial culture was fermented in different culture media for 67 days to test its biological potential against bacterial biofilms. Sclerin, sclerin diacid and its 3-methyl monoester (methyl 1-(5-hydroxy-6-carboxylic-2,3,4-trimethylphenyl propionate are here described for the first time from this fungus. Sclerin and its diacid interfered with the biofilm formation of the pathogen Staphylococcus aureus, inhibiting 86% and 80% of the biofilm at 256 μg mL−1, respectively, but not killing the bacterium. Interestingly, the monomethylester of sclerin diacid was inactive. Although these compounds did not possess any activity against a pre-formed biofilm, they prevented its formation at subtoxic concentrations. Furthermore, sclerin and its diacid displayed a high specificity against Staphylococcus aureus, indicating a good strategy against pathogenic biofilms when combined with antibiotics.

  13. The Effect of Novel Heterocyclic Compounds on Cryptococcal Biofilm

    Science.gov (United States)

    Korem, Maya; Kagan, Sarah

    2017-01-01

    Biofilm formation by microorganisms depends on their communication by quorum sensing, which is mediated by small diffusible signaling molecules that accumulate in the extracellular environment. During human infection, the pathogenic yeast Cryptococcus neoformans can form biofilm on medical devices, which protects the organism and increases its resistance to antifungal agents. The aim of this study was to test two novel heterocyclic compounds, S-8 (thiazolidinedione derivative, TZD) and NA-8 (succinimide derivative, SI), for their anti-biofilm activity against strains of Cryptococcus neoformans and Cryptococcus gattii. Biofilms were formed in a defined medium in 96-well polystyrene plates and 8-well micro-slides. The effect of sub-inhibitory concentrations of S-8 and NA-8 on biofilm formation was measured after 48 h by a metabolic reduction assay and by confocal laser microscopy analysis using fluorescent staining. The formation and development of cryptococcal biofilms was inhibited significantly by these compounds in concentrations below the minimum inhibitory concentration (MIC) values. These compounds may have a potential role in preventing fungal biofilm development on indwelling medical devices or even as a therapeutic measure after the establishment of biofilm. PMID:29371559

  14. Extracellular DNA is essential for maintaining Bordetella biofilm integrity on abiotic surfaces and in the upper respiratory tract of mice.

    Directory of Open Access Journals (Sweden)

    Matt S Conover

    2011-02-01

    Full Text Available Bacteria form complex and highly elaborate surface adherent communities known as biofilms which are held together by a self-produced extracellular matrix. We have previously shown that by adopting a biofilm mode of existence in vivo, the gram negative bacterial pathogens Bordetella bronchiseptica and Bordetella pertussis are able to efficiently colonize and persist in the mammalian respiratory tract. In general, the bacterial biofilm matrix includes polysaccharides, proteins and extracellular DNA (eDNA. In this report, we investigated the function of DNA in Bordetella biofilm development. We show that DNA is a significant component of Bordetella biofilm matrix. Addition of DNase I at the initiation of biofilm growth inhibited biofilm formation. Treatment of pre-established mature biofilms formed under both static and flow conditions with DNase I led to a disruption of the biofilm biomass. We next investigated whether eDNA played a role in biofilms formed in the mouse respiratory tract. DNase I treatment of nasal biofilms caused considerable dissolution of the biofilm biomass. In conclusion, these results suggest that eDNA is a crucial structural matrix component of both in vitro and in vivo formed Bordetella biofilms. This is the first evidence for the ability of DNase I to disrupt bacterial biofilms formed on host organs.

  15. Microsensor and transcriptomic signatures of oxygen depletion in biofilms associated with chronic wounds: Biofilms and oxygen

    Energy Technology Data Exchange (ETDEWEB)

    James, Garth A. [Center for Biofilm Engineering, Montana State University, Bozeman Montana; Ge Zhao, Alice [Division of Dermatology, Department of Medicine, University of Washington, Seattle Washington; Usui, Marcia [Division of Dermatology, Department of Medicine, University of Washington, Seattle Washington; Underwood, Robert A. [Division of Dermatology, Department of Medicine, University of Washington, Seattle Washington; Nguyen, Hung [The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman Washington; Beyenal, Haluk [The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman Washington; deLancey Pulcini, Elinor [Center for Biofilm Engineering, Montana State University, Bozeman Montana; Agostinho Hunt, Alessandra [Department of Microbiology and Molecular Genetics, 5180 Biomedical and Physical Sciences, Michigan State University, East Lansing Michigan; Bernstein, Hans C. [Pacific Northwest National Laboratory, Chemical and Biological Signature Science, Richland Washington; Fleckman, Philip [Division of Dermatology, Department of Medicine, University of Washington, Seattle Washington; Olerud, John [Division of Dermatology, Department of Medicine, University of Washington, Seattle Washington; Williamson, Kerry S. [Center for Biofilm Engineering, Montana State University, Bozeman Montana; Franklin, Michael J. [Center for Biofilm Engineering, Montana State University, Bozeman Montana; Stewart, Philip S. [Center for Biofilm Engineering, Montana State University, Bozeman Montana

    2016-02-16

    Polymicrobial biofilms have been implicated in delayed wound healing, although the mechanisms by which biofilms impair wound healing are poorly understood. Many species of bacteria produce exotoxins and exoenzymes that may inhibit healing. In addition, oxygen consumption by biofilms may impede wound healing. In this study, we used oxygen microsensors to measure oxygen transects through in vitro-cultured biofilms, biofilms formed in vivo in a diabetic (db/db) mouse model, and ex vivo human chronic wound specimens. The results show that oxygen levels within both euthanized and live mouse wounds had steep gradients that reached minima ranging from 19 to 61% oxygen partial pressure, compared to atmospheric oxygen levels. The oxygen gradients in the mouse wounds were similar to those observed for clinical isolates cultured in vitro and for human ex vivo scabs. No oxygen gradients were observed for heat-killed scabs, suggesting that active metabolism by the viable bacteria contributed to the reduced oxygen partial pressure of the wounds. To characterize the metabolic activities of the bacteria in the mouse wounds, we performed transcriptomics analyses of Pseudomonas aeruginosa biofilms associated with the db/db mice wounds using Affymetrix microarrays. The results demonstrated that the bacteria expressed genes for metabolic activities associated with cell growth. Interestingly, the transcriptome results indicated that the bacteria within the wounds also experienced oxygen-limitation stress. Among the bacterial genes that were expressed in vivo were genes associated with the Anr-mediated hypoxia-stress response. Other bacterial stress response genes highly expressed in vivo were genes associated with stationary-phase growth, osmotic stress, and RpoH-mediated heat shock stress. Overall, the results support the hypothesis that the metabolic activities of bacteria in biofilms act as oxygen sinks in chronic wounds and that the depletion of oxygen contributes to the

  16. Treatment of Oral Biofilms by a D-Enantiomeric Peptide.

    Science.gov (United States)

    Zhang, Tian; Wang, Zhejun; Hancock, Robert E W; de la Fuente-Núñez, César; Haapasalo, Markus

    2016-01-01

    Almost all dental diseases are caused by biofilms that consist of multispecies communities. DJK-5, which is a short D-enantiomeric, protease-resistant peptide with broad-spectrum anti-biofilm activity, was tested for its effect on oral multispecies biofilms. Peptide DJK-5 at 10 μg/mL effectively prevented the growth of these microbes in culture media in a time-dependent manner. In addition to the prevention of growth, peptide DJK-5 completely killed both Streptococcus mutans and Enterococcus faecalis suspended from biofilms after 30 minutes of incubation in liquid culture media. DJK-5 also led to the effective killing of microbes in plaque biofilm. The proportion of bacterial cells killed by 10 μg/mL of DJK-5 was similar after 1 and 3 days, both exceeding 85%. DJK-5 was able to significantly prevent biofilm formation over 3 days (P = 0.000). After 72 hours of exposure, DJK-5 significantly reduced and almost completely prevented plaque biofilm production by more than 90% of biovolume compared to untreated controls (P = 0.000). The proportion of dead biofilm bacteria at the 10 μg/mL DJK-5 concentration was similar for 1- and 3-day-old biofilms, whereby >86% of the bacteria were killed. DJK-5 was also able to kill >79% and >85% of bacteria, respectively, after one-time and three brief treatments of 3-day-old biofilms. The combination of DJK-5 and chlorhexidine showed the best bacterial killing among all treatments, with ~83% and >88% of bacterial cells killed after 1 and 3 minutes, respectively. No significant difference was found in the percentage of biofilm killing amongst three donor plaque samples after DJK-5 treatment. In particular, DJK-5 showed strong performance in inhibiting biofilm development and eradicating pre-formed oral biofilms compared to L-enantiomeric peptide 1018. DJK-5 was very effective against oral biofilms when used alone or combined with chlorhexidine, and may be a promising agent for use in oral anti-biofilm strategies in the future.

  17. Meningococcal biofilm formation

    DEFF Research Database (Denmark)

    Lappann, M.; Haagensen, Janus Anders Juul; Claus, H.

    2006-01-01

    We show that in a standardized in vitro flow system unencapsulated variants of genetically diverse lineages of Neisseria meningitidis formed biofilms, that could be maintained for more than 96 h. Biofilm cells were resistant to penicillin, but not to rifampin or ciprofloxacin. For some strains......, microcolony formation within biofilms was observed. Microcolony formation in strain MC58 depended on a functional copy of the pilE gene encoding the pilus subunit pilin, and was associated with twitching of cells. Nevertheless, unpiliated pilE mutants formed biofilms showing that attachment and accumulation......X alleles was identified among genetically diverse meningococcal strains. PilX alleles differed in their propensity to support autoaggregation of cells in suspension, but not in their ability to support microcolony formation within biofilms in the continuous flow system....

  18. Biofilms in wounds

    DEFF Research Database (Denmark)

    Cooper, R A; Bjarnsholt, Thomas; Alhede, M

    2014-01-01

    Following confirmation of the presence of biofilms in chronic wounds, the term biofilm became a buzzword within the wound healing community. For more than a century pathogens have been successfully isolated and identified from wound specimens using techniques that were devised in the nineteenth...... extracellular polymeric substances (EPS). Cells within such aggregations (or biofilms) display varying physiological and metabolic properties that are distinct from those of planktonic cells, and which contribute to their persistence. There are many factors that influence healing in wounds and the discovery...... of biofilms in chronic wounds has provided new insight into the reasons why. Increased tolerance of biofilms to antimicrobial agents explains the limited efficacy of antimicrobial agents in chronic wounds and illustrates the need to develop new management strategies. This review aims to explain the nature...

  19. Hydroxychalcone inhibitors of Streptococcus mutans glucosyl transferases and biofilms as potential anticaries agents.

    Science.gov (United States)

    Nijampatnam, Bhavitavya; Casals, Luke; Zheng, Ruowen; Wu, Hui; Velu, Sadanandan E

    2016-08-01

    Streptococcus mutans has been implicated as the major etiological agent in the initiation and the development of dental caries due to its robust capacity to form tenacious biofilms. Ideal therapeutics for this disease will aim to selectively inhibit the biofilm formation process while preserving the natural bacterial flora of the mouth. Several studies have demonstrated the efficacies of flavonols on S. mutans biofilms and have suggested the mechanism of action through their effect on S. mutans glucosyltransferases (Gtfs). These enzymes metabolize sucrose into water insoluble and soluble glucans, which are an integral measure of the dental caries pathogenesis. Numerous studies have shown that flavonols and polyphenols can inhibit Gtf and biofilm formation at millimolar concentrations. We have screened a group of 14 hydroxychalcones, synthetic precursors of flavonols, in an S. mutans biofilm assay. Several of these compounds emerged to be biofilm inhibitors at low micro-molar concentrations. Chalcones that contained a 3-OH group on ring A exhibited selectivity for biofilm inhibition. Moreover, we synthesized 6 additional analogs of the lead compound and evaluated their potential activity and selectivity against S. mutans biofilms. The most active compound identified from these studies had an IC50 value of 44μM against biofilm and MIC50 value of 468μM against growth displaying >10-fold selectivity inhibition towards biofilm. The lead compound displayed a dose dependent inhibition of S. mutans Gtfs. The lead compound also did not affect the growth of two commensal species (Streptococcus sanguinis and Streptococcus gordonii) at least up to 200μM, indicating that it can selectively inhibit cariogenic biofilms, while leaving commensal and/or beneficial microbes intact. Thus non-toxic compounds have the potential utility in public oral health regimes. Copyright © 2016. Published by Elsevier Ltd.

  20. In Vitro Effects of Sports and Energy Drinks on Streptococcus mutans Biofilm Formation and Metabolic Activity.

    Science.gov (United States)

    Vinson, LaQuia A; Goodlett, Amy K; Huang, Ruijie; Eckert, George J; Gregory, Richard L

    2017-09-15

    Sports and energy drinks are being increasingly consumed and contain large amounts of sugars, which are known to increase Streptococcus mutans biofilm formation and metabolic activity. The purpose of this in vitro study was to investigate the effects of sports and energy drinks on S. mutans biofilm formation and metabolic activity. S. mutans UA159 was cultured with and without a dilution (1:3 ratio) of a variety of sports and energy drinks in bacterial media for 24 hours. The biofilm was washed, fixed, and stained. Biofilm growth was evaluated by reading absorbance of the crystal violet. Biofilm metabolic activity was measured by the biofilm-reducing XTT to a water-soluble orange compound. Gatorade Protein Recovery Shake and Starbucks Doubleshot Espresso Energy were found to significantly increase biofilm (30-fold and 22-fold, respectively) and metabolic activity (2-fold and 3-fold, respectively). However, most of the remaining drinks significantly inhibited biofilm growth and metabolic activity. Several sports and energy drinks, with sugars or sugar substitutes as their main ingredients inhibited S. mutans biofilm formation. Among the drinks evaluated, Gatorade Protein Recovery Chocolate Shake and Starbucks Doubleshot Energy appear to have cariogenic potential since they increased the biofilm formation and metabolic activity of S. mutans.

  1. Abolition of Biofilm Formation in Urinary Tract Escherichia coli and Klebsiella Isolates by Metal Interference through Competition for Fur

    DEFF Research Database (Denmark)

    Hancock, Viktoria; Dahl, Malin; Klemm, Per

    2010-01-01

    Bacterial biofilms are associated with a large number of persistent and chronic infections. Biofilm-dwelling bacteria are particularly resistant to antibiotics and immune defenses, which makes it hard if not impossible to eradicate biofilm-associated infections. In the urinary tract, free iron...... is strictly limited but is critical for bacterial growth. Biofilm-associated Escherichia coli cells are particularly desperate for iron. An attractive way of inhibiting biofilm formation is to fool the bacterial regulatory system for iron uptake. Here, we demonstrate that biofilm formation can be impaired...... by the addition of divalent metal ions, such as Zn(II) and Co(II), which inhibit iron uptake by virtue of their higher-than-iron affinity for the master controller protein of iron uptake, Fur. Reduced biofilm formation of urinary tract-infectious E. coli strains in the presence of Zn(II) was observed...

  2. Effect of antibacterial dental adhesive on multispecies biofilms formation.

    Science.gov (United States)

    Zhang, K; Wang, S; Zhou, X; Xu, H H K; Weir, M D; Ge, Y; Li, M; Wang, S; Li, Y; Xu, X; Zheng, L; Cheng, L

    2015-04-01

    Antibacterial adhesives have favorable prospects to inhibit biofilms and secondary caries. The objectives of this study were to investigate the antibacterial effect of dental adhesives containing dimethylaminododecyl methacrylate (DMADDM) on different bacteria in controlled multispecies biofilms and its regulating effect on development of biofilm for the first time. Antibacterial material was synthesized, and Streptococcus mutans, Streptococcus gordonii, and Streptococcus sanguinis were chosen to form multispecies biofilms. Lactic acid assay and pH measurement were conducted to study the acid production of controlled multispecies biofilms. Anthrone method and exopolysaccharide (EPS):bacteria volume ratio measured by confocal laser scanning microscopy were performed to determine the EPS production of biofilms. The colony-forming unit counts, scanning electron microscope imaging, and dead:live volume ratio decided by confocal laser scanning microscopy were used to study the biomass change of controlled multispecies biofilms. The TaqMan real-time polymerase chain reaction and fluorescent in situ hybridization imaging were used to study the proportion change in multispecies biofilms of different groups. The results showed that DMADDM-containing adhesive groups slowed the pH drop and decreased the lactic acid production noticeably, especially lactic acid production in the 5% DMADDM group, which decreased 10- to 30-fold compared with control group (P biofilms compared with control group (P biofilm had a more healthy development tendency after the regulation of DMADDM. In conclusion, the adhesives containing DMADDM had remarkable antimicrobial properties to serve as "bioactive" adhesive materials and revealed its potential value for antibiofilm and anticaries clinical applications. © International & American Associations for Dental Research 2015.

  3. Anti-biofilm efficacy of low temperature processed AgCl–TiO2 nanocomposite coating

    International Nuclear Information System (INIS)

    Naik, Kshipra; Kowshik, Meenal

    2014-01-01

    Biofilms are a major concern in the medical settings and food industries due to their high tolerance to antibiotics, biocides and mechanical stress. Currently, the development of novel methods to control biofilm formation is being actively pursued. In the present study, sol–gel coatings of AgCl–TiO 2 nanoparticles are presented as potential anti-biofilm agents, wherein TiO 2 acts as a good supporting matrix to prevent aggregation of silver and facilitates its controlled release. Low-temperature processed AgCl–TiO 2 nanocomposite coatings inhibit biofilm formation by Escherichia coli, Staphylococcus epidermidis and Pseudomonas aeruginosa. In vitro biofilm assay experiments demonstrated that AgCl–TiO 2 nanocomposite coated surfaces, inhibited the development of biofilms over a period of 10 days as confirmed by scanning electron microscopy. The silver release kinetics exhibited an initial high release, followed by a slow and sustained release. The anti-biofilm efficacy of the coatings could be attributed to the release of silver, which prevents the initial bacterial adhesion required for biofilm formation. - Highlights: • Potential of AgCl–TiO 2 nanocomposite coating to inhibit biofilm formation is exhibited. • Initial rapid release followed by later slow and sustained release of silver obtained. • TiO 2 being porous and inorganic in nature acts as a good supporting matrix

  4. Biofilm-mediated Antibiotic-resistant Oral Bacterial Infections: Mechanism and Combat Strategies.

    Science.gov (United States)

    Kanwar, Indulata; Sah, Abhishek K; Suresh, Preeti K

    2017-01-01

    Oral diseases like dental caries and periodontal disease are directly associated with the capability of bacteria to form biofilm. Periodontal diseases have been associated to anaerobic Gram-negative bacteria forming a subgingival plaque (Porphyromonas gingivalis, Actinobacillus, Prevotella and Fusobacterium). Biofilm is a complex bacterial community that is highly resistant to antibiotics and human immunity. Biofilm communities are the causative agents of biological developments such as dental caries, periodontitis, peri-implantitis and causing periodontal tissue breakdown. The review recapitulates the latest advancements in treatment of clinical biofilm infections and scientific investigations, while these novel anti-biofilm strategies are still in nascent phases of development, efforts dedicated to these technologies could ultimately lead to anti-biofilm therapies that are superior to the current antibiotic treatment. This paper provides a review of the literature focusing on the studies on biofilm in the oral cavity, formation of dental plaque biofilm, drug resistance of bacterial biofilm and the antibiofilm approaches as biofilm preventive agents in dentistry, and their mechanism of biofilm inhibition. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  5. Antibiofilm activity of carboxymethyl chitosan on the biofilms of non-Candida albicans Candida species.

    Science.gov (United States)

    Tan, Yulong; Leonhard, Matthias; Moser, Doris; Schneider-Stickler, Berit

    2016-09-20

    Although most cases of candidiasis have been attributed to Candida albicans, non-C. albicans Candida species have been isolated in increasing numbers in patients. In this study, we determined the inhibition of carboxymethyl chitosan (CM-chitosan) on single and mixed species biofilm of non-albicans Candida species, including Candida tropicalis, Candida parapsilosis, Candida krusei and Candida glabrata. Biofilm by all tested species in microtiter plates were inhibited nearly 70%. CM-chitosan inhibited mixed species biofilm in microtiter plates and also on medical materials surfaces. To investigate the mechanism, the effect of CM-chitosan on cell viability and biofilm growth was employed. CM-chitosan inhibited Candida planktonic growth as well as adhesion. Further biofilm formation was inhibited with CM-chitosan added at 90min, 12h or 24h after biofilm initiation. CM-chitosan was not only able to inhibit the metabolic activity of Candida cells, but was also active upon the establishment and the development of biofilms. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. An exploration of the effects of Commiphora glileadenis on a Streptococcus mutans biofilm

    Directory of Open Access Journals (Sweden)

    Hossam A Eid

    2015-01-01

    Conclusion: Myrrh plant extract has promising antibacterial effect as well as on biofilm inhibition of S. mutans. The significant antimicrobial effect of the Myrrh plant extract indicates about its promise in controlling S. mutans biofilm, which has suspected role in the etiology of dental caries and periodontal diseases.

  7. Studying bacterial multispecies biofilms

    DEFF Research Database (Denmark)

    Røder, Henriette Lyng; Sørensen, Søren Johannes; Burmølle, Mette

    2016-01-01

    The high prevalence and significance of multispecies biofilms have now been demonstrated in various bacterial habitats with medical, industrial, and ecological relevance. It is highly evident that several species of bacteria coexist and interact in biofilms, which highlights the need for evaluating...... the approaches used to study these complex communities. This review focuses on the establishment of multispecies biofilms in vitro, interspecies interactions in microhabitats, and how to select communities for evaluation. Studies have used different experimental approaches; here we evaluate the benefits...... and drawbacks of varying the degree of complexity. This review aims to facilitate multispecies biofilm research in order to expand the current limited knowledge on interspecies interactions. Recent technological advances have enabled total diversity analysis of highly complex and diverse microbial communities...

  8. Bacterial dynamics in a microphytobenthic biofilm: A tidal mesocosm approach

    Science.gov (United States)

    Agogué, Hélène; Mallet, Clarisse; Orvain, Francis; De Crignis, Margot; Mornet, Françoise; Dupuy, Christine

    2014-09-01

    In intertidal mudflats, during low tide exposure, microphytobenthos (MPB) migrate vertically through the surface sediment and form, with the heterotrophic bacteria, a transient biofilm. Inside this biofilm, multiple interactions exist between MPB and bacteria. These micro-organisms secrete a wide range of extracellular polymeric substances (EPS), which are major components of the biofilm matrix. In this study, we used a tidal mesocosm experiment in order to decipher the interactions of the MPB-EPS-bacteria complex within the biofilm. We tried to determine if the EPS could control bacterial activities and/or production and/or richness according to the age of the biofilm and to the immersion/emersion period. The dynamics of biomasses of MPB and prokaryotes, the bacterial production, the hydrolysis of predominating organic constituents in the dissolved organic carbon (DOC) pool (i.e., carbohydrates and polypeptides), and the bacterial structure were studied in relation to the different EPS fractions (carbohydrates and proteins: colloidal and bound) dynamics during 8 days. Our experiment had emphasized the influence of the environmental conditions (light, immersion/emersion) on the interactions within the biofilm and also on the effects on biofilm aging. Bacterial production was always inhibited by the bound EPS-carbohydrate, especially during low tide. Our results suggest that the concentration and composition of EPS had a major role in the bacterial/MPB interactions: these interactions can be either positive or negative in order to regulate the productive phases of MPB and bacteria.

  9. Effects of commonly used food preservatives on biofilm formation of Streptococcus mutans in vitro.

    Science.gov (United States)

    Al-Ahmad, Ali; Wiedmann-Al-Ahmad, Margit; Auschill, Thorsten Mathias; Follo, Marie; Braun, Gabriele; Hellwig, Elmar; Arweiler, Nicole Birgit

    2008-08-01

    Sodium benzoate (SB), potassium sorbate (PS) and sodium nitrite (SN) are commonly used food preservatives. In this in vitro study, the effects of these substances on biofilm formation of Streptococcus mutans were analysed. In addition to the microtiter plate test (MPT), a biofilm reactor containing bovine enamel slabs (BES) was used to study the influence of food preservatives on biofilm formation in 5 independent periods of 4 days each. These included one period with chlorhexidine digluconate (CHX) as a positive control as well as a period with growth medium alone as a negative control. The vitality of the biofilm on BES was detected using live/dead staining and confocal laser scanning microscopy. Additionally, the number of colony forming units (CFU) was determined. In MPT 0.12% SN significantly reduced the biofilm formation. PS at a concentration of 0.4% tended to inhibit biofilm formation, whereas the inhibition for 0.8% PS was significant. Less inhibition was caused by 0.8% SB. In the biofilm reactor 0.06% of SN, 0.1% of SB and 0.1% PS significantly reduced the covering grade as well as the CFU of the biofilm. Biofilm vitality was reduced significantly by CHX to a level of 32.5% compared to the control. Only SB reduced the vitality to a level of 19.1%. SN and PS showed no influence on biofilm vitality. This study indicates the potential of food preservatives as inhibitory agents in S. mutans biofilm formation, which should be kept in mind when studying the effects of conserved food on dental plaque biofilm in situ.

  10. A Biofilm Matrix-Associated Protease Inhibitor Protects Pseudomonas aeruginosa from Proteolytic Attack.

    Science.gov (United States)

    Tseng, Boo Shan; Reichhardt, Courtney; Merrihew, Gennifer E; Araujo-Hernandez, Sophia A; Harrison, Joe J; MacCoss, Michael J; Parsek, Matthew R

    2018-04-10

    Pseudomonas aeruginosa produces an extracellular biofilm matrix that consists of nucleic acids, exopolysaccharides, lipid vesicles, and proteins. In general, the protein component of the biofilm matrix is poorly defined and understudied relative to the other major matrix constituents. While matrix proteins have been suggested to provide many functions to the biofilm, only proteins that play a structural role have been characterized thus far. Here we identify proteins enriched in the matrix of P. aeruginosa biofilms. We then focused on a candidate matrix protein, the serine protease inhibitor ecotin (PA2755). This protein is able to inhibit neutrophil elastase, a bactericidal enzyme produced by the host immune system during P. aeruginosa biofilm infections. We show that ecotin binds to the key biofilm matrix exopolysaccharide Psl and that it can inhibit neutrophil elastase when associated with Psl. Finally, we show that ecotin protects both planktonic and biofilm P. aeruginosa cells from neutrophil elastase-mediated killing. This may represent a novel mechanism of protection for biofilms to increase their tolerance against the innate immune response. IMPORTANCE Proteins associated with the extracellular matrix of bacterial aggregates called biofilms have long been suggested to provide many important functions to the community. To date, however, only proteins that provide structural roles have been described, and few matrix-associated proteins have been identified. We developed a method to identify matrix proteins and characterized one. We show that this protein, when associated with the biofilm matrix, can inhibit a bactericidal enzyme produced by the immune system during infection and protect biofilm cells from death induced by the enzyme. This may represent a novel mechanism of protection for biofilms, further increasing their tolerance against the immune response. Together, our results are the first to show a nonstructural function for a confirmed matrix

  11. Compaction and relaxation of biofilms

    KAUST Repository

    Valladares Linares, R.

    2015-06-18

    Operation of membrane systems for water treatment can be seriously hampered by biofouling. A better characterization of biofilms in membrane systems and their impact on membrane performance may help to develop effective biofouling control strategies. The objective of this study was to determine the occurrence, extent and timescale of biofilm compaction and relaxation (decompaction), caused by permeate flux variations. The impact of permeate flux changes on biofilm thickness, structure and stiffness was investigated in situ and non-destructively with optical coherence tomography using membrane fouling monitors operated at a constant crossflow velocity of 0.1 m s−1 with permeate production. The permeate flux was varied sequentially from 20 to 60 and back to 20 L m−2 h−1. The study showed that the average biofilm thickness on the membrane decreased after elevating the permeate flux from 20 to 60 L m−2 h−1 while the biofilm thickness increased again after restoring the original flux of 20 L m−2 h−1, indicating the occurrence of biofilm compaction and relaxation. Within a few seconds after the flux change, the biofilm thickness was changed and stabilized, biofilm compaction occurred faster than the relaxation after restoring the original permeate flux. The initial biofilm parameters were not fully reinstated: the biofilm thickness was reduced by 21%, biofilm stiffness had increased and the hydraulic biofilm resistance was elevated by 16%. Biofilm thickness was related to the hydraulic biofilm resistance. Membrane performance losses are related to the biofilm thickness, density and morphology, which are influenced by (variations in) hydraulic conditions. A (temporarily) permeate flux increase caused biofilm compaction, together with membrane performance losses. The impact of biofilms on membrane performance can be influenced (increased and reduced) by operational parameters. The article shows that a (temporary) pressure increase leads to more

  12. Biofilm formation and disinfectant resistance of Salmonella sp. in mono- and dual-species with Pseudomonas aeruginosa.

    Science.gov (United States)

    Pang, X Y; Yang, Y S; Yuk, H G

    2017-09-01

    This study aimed to evaluate the biofilm formation and disinfectant resistance of Salmonella cells in mono- and dual-species biofilms with Pseudomonas aeruginosa, and to investigate the role of extracellular polymeric substances (EPS) in the protection of biofilms against disinfection treatment. The populations of Salmonella in mono- or dual-species biofilms with P. aeruginosa on stainless steel (SS) coupons were determined before and after exposure to commercial disinfectant, 50 μg ml -1 chlorine or 200 μg ml -1 Ecolab ® Whisper™ V (a blend of four effective quaternary ammonium compounds (QAC)). In addition, EPS amount from biofilms was quantified and biofilm structures were observed using scanning electron microscopy (SEM). Antagonistic interactions between Salmonella and P. aeruginosa resulted in lower planktonic population level of Salmonella, and lower density in dual-species biofilms compared to mono-species biofilms. The presence of P. aeruginosa significantly enhanced disinfectant resistance of S. Typhimurium and S. Enteritidis biofilm cells for 2 days, and led to an average of 50% increase in polysaccharides amount in dual-species biofilms than mono-species biofilms of Salmonella. Microscopy observation showed the presence of large microcolonies covered by EPS in dual-species biofilms but not in mono-species ones. The presence of P. aeruginosa in dual-species culture inhibited the growth of Salmonella cells in planktonic phase and in biofilms, but protected Salmonella cells in biofilms from disinfection treatment, by providing more production of EPS in dual-species biofilms than mono-species ones. This study provides insights into inter-species interaction, with regard to biofilm population dynamics and disinfectant resistance. Thus, a sanitation protocol should be designed considering the protective role of secondary species to pathogens in biofilms on SS surface which has been widely used at food surfaces and manufacturers. © 2017 The Society

  13. Interactions in multispecies biofilms

    DEFF Research Database (Denmark)

    Burmølle, Mette; Ren, Dawei; Bjarnsholt, Thomas

    2014-01-01

    The recent focus on complex bacterial communities has led to the recognition of interactions across species boundaries. This is particularly pronounced in multispecies biofilms, where synergistic interactions impact the bacterial distribution and overall biomass produced. Importantly, in a number...... of settings, the interactions in a multispecies biofilm affect its overall function, physiology, or surroundings, by resulting in enhanced resistance, virulence, or degradation of pollutants, which is of significant importance to human health and activities. The underlying mechanisms causing these synergistic...

  14. Bacteriophages and Biofilms

    Directory of Open Access Journals (Sweden)

    David R. Harper

    2014-06-01

    Full Text Available Biofilms are an extremely common adaptation, allowing bacteria to colonize hostile environments. They present unique problems for antibiotics and biocides, both due to the nature of the extracellular matrix and to the presence within the biofilm of metabolically inactive persister cells. Such chemicals can be highly effective against planktonic bacterial cells, while being essentially ineffective against biofilms. By contrast, bacteriophages seem to have a greater ability to target this common form of bacterial growth. The high numbers of bacteria present within biofilms actually facilitate the action of bacteriophages by allowing rapid and efficient infection of the host and consequent amplification of the bacteriophage. Bacteriophages also have a number of properties that make biofilms susceptible to their action. They are known to produce (or to be able to induce enzymes that degrade the extracellular matrix. They are also able to infect persister cells, remaining dormant within them, but re-activating when they become metabolically active. Some cultured biofilms also seem better able to support the replication of bacteriophages than comparable planktonic systems. It is perhaps unsurprising that bacteriophages, as the natural predators of bacteria, have the ability to target this common form of bacterial life.

  15. Bovine milk osteopontin - Targeting bacterial adhesion for biofilm control

    DEFF Research Database (Denmark)

    Kristensen, Mathilde Frost; Meyer, Rikke Louise; Schlafer, Sebastian

    2016-01-01

    Self-performed mechanical tooth cleaning does usually not result in complete biofilm removal, due to the complex oral anatomy and the strong adhesion of the biofilm to the tooth. Therefore, different supportive measures are employed, most of which aim at the chemical eradication of bacteria...... in dental biofilms. As their bactericidal action impacts the entire oral microflora, agents that inhibit biofilm formation without killing bacteria, such as the bovine milk protein osteopontin, have gained increasing attention. Here, we investigate the adhesion of 8 bacterial species associated with dental...... subsp. paracasei, Streptococcus mitis and Streptococcus oralis with 74.0%, 62.4%, 90.0%, 89.6% and 81.5%, respectively, compared to protein-free saliva. All reductions were statistically significant (p

  16. EFFECT OF ESSENTIAL OIL ON BIOFILM PRODUCTION BY DIFFERENT LISTERIA MONOCYTOGENES STRAINS

    Directory of Open Access Journals (Sweden)

    G. Comi

    2008-12-01

    Full Text Available The effects of different essential oil (hexanal, 2-(E-hexenal, carvacrol, citron, red orange, thymol and limonene on biofilm production of some Lmonocytogenes strains are evaluated. The formation of biofilm on certain surfaces or on the food, seems to be related with cross-contamination during processing or with the contamination of the final product, with potential risk for the consumer. Many studies were done on the antimicrobial activity of essential oils and their components, but not too much is known about their capacity to influence and reduce the microbial production of biofilm. Our data showed that essential oils can inhibit or limit the biofilm production.

  17. Inhibitory effects of flavonoids on biofilm formation by Staphylococcus aureus that overexpresses efflux protein genes.

    Science.gov (United States)

    Lopes, Laênia Angélica Andrade; Dos Santos Rodrigues, Jéssica Bezerra; Magnani, Marciane; de Souza, Evandro Leite; de Siqueira-Júnior, José P

    2017-06-01

    This study evaluated the efficacy of glycone (myricitrin, hesperidin and phloridzin) and aglycone flavonoids (myricetin, hesperetin and phloretin) in inhibiting biofilm formation by Staphylococcus aureus RN4220 and S. aureus SA1199B that overexpress the msrA and norA efflux protein genes, respectively. The minimum inhibitory concentration (MIC) and minimum biofilm inhibitory concentration (MBIC 50 - defined as the lowest concentration that resulted in ≥50% inhibition of biofilm formation) of flavonoids were determined using microdilution in broth procedures. The flavonoids showed MIC >1024 μg/mL against S. aureus RN4220 and S. aureus SA1199B; however, these compounds at lower concentrations (1-256 μg/mL) showed inhibitory effects on biofilm formation by these strains. Aglycone flavonoids showed lower MBIC 50 values than their respective glycone forms. The lowest MBIC 50 values (1 and 4 μg/mL) were observed against S. aureus RN4220. Myricetin, hesperetin and phloretin exhibited biofilm formation inhibition >70% for S. aureus RN4220, and lower biofilm formation inhibition against S. aureus SA1199B. These results indicate that sub-MICs of the tested flavonoids inhibit biofilm formation by S. aureus strains that overexpress efflux protein genes. These effects are more strongly established by aglycone flavonoids. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Natural isothiocyanates express antimicrobial activity against developing and mature biofilms of Pseudomonas aeruginosa.

    Science.gov (United States)

    Kaiser, Stefan J; Mutters, Nico T; Blessing, Brigitte; Günther, Frank

    2017-06-01

    The antimicrobial properties of natural isothiocyanates (ITCs) found in plants such as nasturtium (Tropaeolum majus) and horseradish (Armoracia rusticana), and the need of new chemotherapeutic options for treatment of infections caused by multidrug-resistant and biofilm-forming Gram-negative bacteria such as Pseudomonas aeruginosa (Pa), led us to evaluate the effects of three major ITCs, allylisothiocyanate (AITC), benzylisothiocyanate (BITC), and phenylethyl-isothiocyanate (PEITC), and a mixture (ITCM) adapted to the ITC composition after release of active components out of natural sources. Out of 105Pa isolates 27 isolates with increased biofilm formation were selected for testing. The effects of ITCs on Pa were evaluated regarding (1) planktonic bacterial proliferation, (2) biofilm formation, (3) metabolic activity in mature biofilms, and (4) synergism of ITCs and antibiotics. (1) Each ITC had anti-Pa activity. Mean minimum inhibitory concentrations (MICs) were (μg/ml, mean±standard deviation): AITC 103±6.9; BITC, 2145±249; PEITC 29,423±1652; and ITCM, 140±5. (2) Treating bacteria with PEITC and ITCM in concentrations below the MIC significantly inhibited biofilm formation. Particularly, ITCM reduced biofilm mass and bacterial proliferation. (3) ITCs significantly inhibited metabolic activity in mature biofilms. (4) Combining ITCs with meropenem synergistically increased antimicrobial efficacy on Pa biofilms. ITCs represent a promising group of natural anti-infective compounds with activity against Pa biofilms. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  19. Evaluation of various metallic coatings on steel to mitigate biofilm formation.

    Science.gov (United States)

    Kanematsu, Hideyuki; Ikigai, Hajime; Yoshitake, Michiko

    2009-02-01

    In marine environments and water systems, it is easy for many structures to form biofilms on their surfaces and to be deteriorated due to the corrosion caused by biofilm formation by bacteria. The authors have investigated the antibacterial effects of metallic elements in practical steels so far to solve food-related problems, using Escherichia coli and Staphylococcus aureus. However, from the viewpoint of material deterioration caused by bacteria and their antifouling measures, we should consider the biofilm behavior as aggregate rather than individual bacterium. Therefore, we picked up Pseudomonas aeruginosa and Pseudoalteromonas carageenovara in this study, since they easily form biofilms in estuarine and marine environments. We investigated what kind of metallic elements could inhibit the biofilm formation at first and then discussed how the thin films of those inhibitory elements on steels could affect biofilm formation. The information would lead to the establishment of effective antifouling measures against corrosion in estuarine and marine environments.

  20. Evaluation of Various Metallic Coatings on Steel to Mitigate Biofilm Formation

    Directory of Open Access Journals (Sweden)

    Hajime Ikigai

    2009-02-01

    Full Text Available In marine environments and water systems, it is easy for many structures to form biofilms on their surfaces and to be deteriorated due to the corrosion caused by biofilm formation by bacteria. The authors have investigated the antibacterial effects of metallic elements in practical steels so far to solve food-related problems, using Escherichia coli and Staphylococcus aureus. However, from the viewpoint of material deterioration caused by bacteria and their antifouling measures, we should consider the biofilm behavior as aggregate rather than individual bacterium. Therefore, we picked up Pseudomonas aeruginosa and Pseudoalteromonas carageenovara in this study, since they easily form biofilms in estuarine and marine environments. We investigated what kind of metallic elements could inhibit the biofilm formation at first and then discussed how the thin films of those inhibitory elements on steels could affect biofilm formation. The information would lead to the establishment of effective antifouling measures against corrosion in estuarine and marine environments.

  1. The Small Molecule DAM Inhibitor, Pyrimidinedione, Disrupts Streptococcus pneumoniae Biofilm Growth In Vitro.

    Directory of Open Access Journals (Sweden)

    Mukesh Kumar Yadav

    Full Text Available Streptococcus pneumoniae persist in the human nasopharynx within organized biofilms. However, expansion to other tissues may cause severe infections such as pneumonia, otitis media, bacteremia, and meningitis, especially in children and the elderly. Bacteria within biofilms possess increased tolerance to antibiotics and are able to resist host defense systems. Bacteria within biofilms exhibit different physiology, metabolism, and gene expression profiles than planktonic cells. These differences underscore the need to identify alternative therapeutic targets and novel antimicrobial compounds that are effective against pneumococcal biofilms. In bacteria, DNA adenine methyltransferase (Dam alters pathogenic gene expression and catalyzes the methylation of adenine in the DNA duplex and of macromolecules during the activated methyl cycle (AMC. In pneumococci, AMC is involved in the biosynthesis of quorum sensing molecules that regulate competence and biofilm formation. In this study, we examine the effect of a small molecule Dam inhibitor, pyrimidinedione, on Streptococcus pneumoniae biofilm formation and evaluate the changes in global gene expression within biofilms via microarray analysis. The effects of pyrimidinedione on in vitro biofilms were studied using a static microtiter plate assay, and the architecture of the biofilms was viewed using confocal and scanning electron microscopy. The cytotoxicity of pyrimidinedione was tested on a human middle ear epithelium cell line by CCK-8. In situ oligonucleotide microarray was used to compare the global gene expression of Streptococcus pneumoniae D39 within biofilms grown in the presence and absence of pyrimidinedione. Real-time RT-PCR was used to study gene expression. Pyrimidinedione inhibits pneumococcal biofilm growth in vitro in a concentration-dependent manner, but it does not inhibit planktonic cell growth. Confocal microscopy analysis revealed the absence of organized biofilms, where cell

  2. Biofilm-Forming Staphylococcus epidermidis Expressing Vancomycin Resistance Early after Adhesion to a Metal Surface

    Directory of Open Access Journals (Sweden)

    Toshiyuki Sakimura

    2015-01-01

    Full Text Available We investigated biofilm formation and time of vancomycin (VCM resistance expression after adhesion to a metal surface in Staphylococcus epidermidis. Biofilm-forming Staphylococcus epidermidis with a VCM MIC of 1 μg/mL was used. The bacteria were made to adhere to a stainless steel washer and treated with VCM at different times and concentrations. VCM was administered 0, 2, 4, and 8 hours after adhesion. The amount of biofilm formed was evaluated based on the biofilm coverage rates (BCRs before and after VCM administration, bacterial viability in biofilm was visually observed using the fluorescence staining method, and the viable bacterial count in biofilm was measured. The VCM concentration required to decrease BCR significantly compared with that of VCM-untreated bacteria was 4 μg/mL, even in the 0 hr group. In the 4 and 8 hr groups, VCM could not inhibit biofilm growth even at 1,024 μg/mL. In the 8 hr group, viable bacteria remained in biofilm at a count of 104 CFU even at a high VCM concentration (1,024 μg/mL. It was suggested that biofilm-forming Staphylococcus epidermidis expresses resistance to VCM early after adhesion to a metal surface. Resistance increased over time after adhesion as the biofilm formed, and strong resistance was expressed 4–8 hours after adhesion.

  3. Biofilm inhibitory and eradicating activity of wound care products against Staphylococcus aureus and Staphylococcus epidermidis biofilms in an in vitro chronic wound model.

    Science.gov (United States)

    Brackman, G; De Meyer, L; Nelis, H J; Coenye, T

    2013-06-01

    Although several factors contribute to wound healing, bacterial infections and the presence of biofilm can significantly affect healing. Despite that this clearly indicates that therapies should address biofilm in wounds, only few wound care products have been evaluated for their antibiofilm effect. For this reason, we developed a rapid quantification approach to investigate the efficacy of wound care products on wounds infected with Staphylococcus spp. An in vitro chronic wound infection model was used in which a fluorescent Staph. aureus strain was used to allow the rapid quantification of the bacterial burden after treatment. A good correlation was observed between the fluorescence signal and the bacterial counts. When evaluated in this model, several commonly used wound dressings and wound care products inhibited biofilm formation resulting in a decrease between one and seven log CFU per biofilm compared with biofilm formed in the absence of products. In contrast, most dressings only moderately affected mature biofilms. Our model allowed the rapid quantification of the bacterial burden after treatment. However, the efficacy of treatment varied between the different types of dressings and/or wound care products. Our model can be used to compare the efficacy of wound care products to inhibit biofilm formation and/or eradicate mature biofilms. In addition, the results indicate that treatment of infected wounds should be started as soon as possible and that novel products with more potent antibiofilm activity are needed. © 2013 The Society for Applied Microbiology.

  4. Effects of Total Alkaloids of Sophora alopecuroides on Biofilm Formation in Staphylococcus epidermidis

    Directory of Open Access Journals (Sweden)

    Xue Li

    2016-01-01

    Full Text Available Staphylococcus epidermidis (S. epidermidis is an opportunistic pathogen with low pathogenicity and a cause of the repeated outbreak of bovine mastitis in veterinary clinical settings. In this report, a biofilm model of S. epidermidis was generated and the minimal inhibitory concentration (MIC and sub-MIC (SMIC on bacterial cultures were assessed for the following agents: total alkaloids of Sophora alopecuroides (TASA, ciprofloxacin (CIP, and erythromycin (ERY. The formation and characteristic parameters of biofilm were analyzed in terms of XTT assay, silver staining, and confocal laser scanning microscope (CLSM. Results showed that a sub-MIC of TASA could inhibit 50% biofilm of bacterial activity, while 250-fold MIC of CIP and ERY MICs only inhibited 50% and 47% of biofilm formation, respectively. All three agents could inhibit the biofilm formation at an early stage, but TASA showed a better inhibitory effect on the late stage of biofilm thickening. A morphological analysis using CLSM further confirmed the destruction of biofilm by these agents. These results thus suggest that TASA has an inhibitory effect on biofilm formation of clinic S. epidermidis, which may be a potential agent warranted for further study on the treatment prevention of infection related to S. epidermidis in veterinary clinic.

  5. Optimized candidal biofilm microtiter assay

    NARCIS (Netherlands)

    Krom, Bastiaan P.; Cohen, Jesse B.; Feser, Gail E. McElhaney; Cihlar, Ronald L.

    Microtiter based candidal biofilm formation is commonly being used. Here we describe the analysis of factors influencing the development of candidal biofilms such as the coating with serum, growth medium and pH. The data reported here show that optimal candidal biofilm formation is obtained when

  6. Biofilm formation on abiotic surfaces

    DEFF Research Database (Denmark)

    Tang, Lone

    2011-01-01

    Bacteria can attach to any surface in contact with water and proliferate into complex communities enclosed in an adhesive matrix, these communities are called biofilms. The matrix makes the biofilm difficult to remove by physical means, and bacteria in biofilm can survive treatment with many...

  7. Influence of fluoride on the bacterial composition of a dual-species biofilm composed of Streptococcus mutans and Streptococcus oralis.

    Science.gov (United States)

    Jung, Ji-Eun; Cai, Jian-Na; Cho, Sung-Dae; Song, Kwang-Yeob; Jeon, Jae-Gyu

    2016-10-01

    Despite the widespread use of fluoride for the prevention of dental caries, few studies have demonstrated the effects of fluoride on the bacterial composition of dental biofilms. This study investigated whether fluoride affects the proportion of Streptococcus mutans and S. oralis in mono- and dual-species biofilm models, via microbiological, biochemical, and confocal fluorescence microscope studies. Fluoride did not affect the bacterial count and bio-volume of S. mutans and S. oralis in mono-species biofilms, except for the 24-h-old S. mutans biofilms. However, fluoride reduced the proportion and bio-volume of S. mutans but did not decrease those of S. oralis during both S. oralis and S. mutans dual-species biofilm formation, which may be related to the decrease in extracellular polysaccharide formation by fluoride. These results suggest that fluoride may prevent the shift in the microbial proportion to cariogenic bacteria in dental biofilms, subsequently inhibiting the cariogenic bacteria dominant biofilm formation.

  8. Characterization of the effect of serum and chelating agents on Staphylococcus aureus biofilm formation; chelating agents augment biofilm formation through clumping factor B

    Science.gov (United States)

    Abraham, Nabil Mathew

    Staphylococcus aureus is the causative agent of a diverse array of acute and chronic infections, and some these infections, including infective endocarditis, joint infections, and medical device-associated bloodstream infections, depend upon its capacity to form tenacious biofilms on surfaces. Inserted medical devices such as intravenous catheters, pacemakers, and artificial heart valves save lives, but unfortunately, they can also serve as a substrate on which S. aureus can form a biofilm, attributing S. aureus as a leading cause of medical device-related infections. The major aim of this work was take compounds to which S. aureus would be exposed during infection and to investigate their effects on its capacity to form a biofilm. More specifically, the project investigated the effects of serum, and thereafter of catheter lock solutions on biofilm formation by S. aureus. Pre-coating polystyrene with serum is frequently used as a method to augment biofilm formation. The effect of pre-coating with serum is due to the deposition of extracellular matrix components onto the polystyrene, which are then recognized by MSCRAMMs. We therefore hypothesized that the major component of blood, serum, would induce biofilm formation. Surprisingly, serum actually inhibited biofilm formation. The inhibitory activity was due to a small molecular weight, heat-stable, non-proteinaceous component/s of serum. Serum-mediated inhibition of biofilm formation may represent a previously uncharacterized aspect of host innate immunity that targets the expression of a key bacterial virulence factor: the ability to establish a resistant biofilm. Metal ion chelators like sodium citrate are frequently chosen to lock intravenous catheters because they are regarded as potent inhibitors of bacterial biofilm formation and viability. We found that, while chelating compounds abolished biofilm formation in most strains of S. aureus, they actually augmented the phenotype in a subset of strains. We

  9. Alginate production affects Pseudomonas aeruginosa biofilm development and architecture, but is not essential for biofilm formation

    DEFF Research Database (Denmark)

    Stapper, A.P.; Narasimhan, G.; Oman, D.E.

    2004-01-01

    of their biofilm formation using confocal laser scanning microscopy. Biofilm Image Processing (BIP) and Community Statistics (COMSTAT) software programs were used to provide quantitative measurements of the two-dimensional biofilm images. All three strains formed distinguishable biofilm architectures, indicating...

  10. Dental biofilm infections

    DEFF Research Database (Denmark)

    Larsen, Tove; Fiehn, Nils-Erik

    2017-01-01

    and cause gingival inflammation and breakdown of supporting periodontal fibers and bone and ultimately tooth loss, i.e., gingivitis, chronic or aggressive periodontitis, and around dental implants, peri-implantitis. Furthermore, bacteria from the dental biofilm may spread to other parts of the body......-fermenting bacteria causing demineralization of teeth, dental caries, which may further lead to inflammation and necrosis in the pulp and periapical region, i.e., pulpitis and periapical periodontitis. In supra- and subgingival biofilms, predominantly gram-negative, anaerobic proteolytic bacteria will colonize...

  11. Pseudomonas aeruginosa Biofilms

    DEFF Research Database (Denmark)

    Alhede, Maria; Bjarnsholt, Thomas; Givskov, Michael

    2014-01-01

    biofilms, which protect the aggregated, biopolymer-embedded bacteria from the detrimental actions of antibiotic treatments and host immunity. A key component in the protection against innate immunity is rhamnolipid, which is a quorum sensing (QS)-regulated virulence factor. QS is a cell-to-cell signaling...... mechanism used to coordinate expression of virulence and protection of aggregated biofilm cells. Rhamnolipids are known for their ability to cause hemolysis and have been shown to cause lysis of several cellular components of the human immune system, for example, macrophages and polymorphonuclear leukocytes...

  12. Manipulatiaon of Biofilm Microbial Ecology

    Energy Technology Data Exchange (ETDEWEB)

    Burkhalter, R.; Macnaughton, S.J.; Palmer, R.J.; Smith, C.A.; Whitaker, K.W.; White, D.C.; Zinn, M.; kirkegaard, R.

    1998-08-09

    The Biofilm mode of growth provides such significant advantages to the members of the consortium that most organisms in important habitats are found in biofilms. The study of factors that allow manipulation of biofilm microbes in the biofilm growth state requires that reproducible biofilms by generated. The most effective monitoring of biofilm formation, succession and desquamation is with on-line monitoring of microbial biofilms with flowcell for direct observation. The biofilm growth state incorporates a second important factor, the heterogeneity in the distribution in time and space of the component members of the biofilm consortium. This heterogeneity is reflected not only in the cellular distribution but in the metabolic activity within a population of cells. Activity and cellular distribution can be mapped in four dimensions with confocal microscopy, and function can be ascertained by genetically manipulated reporter functions for specific genes or by vital stains. The methodology for understanding the microbial ecology of biofilms is now much more readily available and the capacity to manipulate biofilms is becoming an important feature of biotechnology.

  13. Bacterial biofilm and associated infections

    Directory of Open Access Journals (Sweden)

    Muhsin Jamal

    2018-01-01

    Full Text Available Microscopic entities, microorganisms that drastically affect human health need to be thoroughly investigated. A biofilm is an architectural colony of microorganisms, within a matrix of extracellular polymeric substance that they produce. Biofilm contains microbial cells adherent to one-another and to a static surface (living or non-living. Bacterial biofilms are usually pathogenic in nature and can cause nosocomial infections. The National Institutes of Health (NIH revealed that among all microbial and chronic infections, 65% and 80%, respectively, are associated with biofilm formation. The process of biofilm formation consists of many steps, starting with attachment to a living or non-living surface that will lead to formation of micro-colony, giving rise to three-dimensional structures and ending up, after maturation, with detachment. During formation of biofilm several species of bacteria communicate with one another, employing quorum sensing. In general, bacterial biofilms show resistance against human immune system, as well as against antibiotics. Health related concerns speak loud due to the biofilm potential to cause diseases, utilizing both device-related and non-device-related infections. In summary, the understanding of bacterial biofilm is important to manage and/or to eradicate biofilm-related diseases. The current review is, therefore, an effort to encompass the current concepts in biofilm formation and its implications in human health and disease.

  14. Manipulation of Biofilm Microbial Ecology

    Energy Technology Data Exchange (ETDEWEB)

    White, D.C.; Palmer, R.J., Jr.; Zinn, M.; Smith, C.A.; Burkhalter, R.; Macnaughton, S.J.; Whitaker, K.W.; Kirkegaard, R.D.

    1998-08-15

    The biofilm mode of growth provides such significant advantages to the members of the consortium that most organisms in important habitats are found in biofilms. The study of factors that allow manipulation of biofilm microbes in the biofilm growth state requires that reproducible biofilms be generated. The most effective monitoring of biofilm formation, succession and desaturation is with on-line monitoring of microbial biofilms with flowcell for direct observation. The biofilm growth state incorporates a second important factor, the heterogeneity in distribution in time and space of the component members of the biofilm consortium. This heterogeneity is reflected not only in the cellular distribution but in the metabolic activity within a population of cells. Activity and cellular distribution can be mapped in four dimensions with confocal microscopy, and function can be ascertained by genetically manipulated reporter functions for specific genes or by vital stains. The methodology for understanding the microbial ecology of biofilms is now much more readily available and the capacity to manipulate biofilms is becoming an important feature of biotechnology.

  15. Biofilm inhibitory effect of chlorhexidine conjugated gold nanoparticles against Klebsiella pneumoniae.

    Science.gov (United States)

    Ahmed, Ayaz; Khan, Anum Khalid; Anwar, Ayaz; Ali, Syed Abid; Shah, Muhammad Raza

    2016-09-01

    Klebsiella pneumoniae (K. pneumoniae) is one of the major pathogen associated with nosocomial infections, especially catheter associated urinary tract infections which involved biofilm formation. This study was designed to evaluate the antibiofilm efficacy of gold nanoparticle conjugated with chlorhexidine (Au-CHX) against K. pneumoniae isolates. Au-CHX was synthesized and analyzed for stability by using UV-Visible spectrophotometry, atomic force microscopy (AFM), fourier transform infrared spectroscopy (FT-IR) and electrospray ionization mass spectroscopy (ESI-MS). Biofilm inhibition and eradication was performed by crystal violet, 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays and further confirmed by florescence and AFM microscopy. Au-CHX showed the maxima surface plasmon resonance (SPR) band at 535 nm, spherical morphology and polydispersity with size in the range of 20-100 nm. The micro molar concentrations (i.e. 25 and 100 μM) of Au-CHX completely inhibited the biofilm formation and metabolic activity within biofilms of K. pneumoniae reference and three tested clinical isolates, respectively. Time dependant biofilm inhibition assay showed that Au-CHX inhibited the early stage of biofilm formation. While at 75 and 100 μM concentrations, it also eradicated the established biofilms of K. pneumoniae isolates as compared to 2 mM chlorhexidine. Reduced florescence signals and surface roughness during microscopic analysis further confirms the antibiofilm activity of Au-CHX against K. pneumoniae ATCC13882 and clinical isolates. Thus it is concluded that chlorhexidine coated gold nanoparticle not only inhibits the biofilm formation of K. pneumoniae ATCC and clinical isolates but also eradicated the preformed biofilm. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Biofilm in endodontics: A review

    Science.gov (United States)

    Jhajharia, Kapil; Parolia, Abhishek; Shetty, K Vikram; Mehta, Lata Kiran

    2015-01-01

    Endodontic disease is a biofilm-mediated infection, and primary aim in the management of endodontic disease is the elimination of bacterial biofilm from the root canal system. The most common endodontic infection is caused by the surface-associated growth of microorganisms. It is important to apply the biofilm concept to endodontic microbiology to understand the pathogenic potential of the root canal microbiota as well as to form the basis for new approaches for disinfection. It is foremost to understand how the biofilm formed by root canal bacteria resists endodontic treatment measures. Bacterial etiology has been confirmed for common oral diseases such as caries and periodontal and endodontic infections. Bacteria causing these diseases are organized in biofilm structures, which are complex microbial communities composed of a great variety of bacteria with different ecological requirements and pathogenic potential. The biofilm community not only gives bacteria effective protection against the host's defense system but also makes them more resistant to a variety of disinfecting agents used as oral hygiene products or in the treatment of infections. Successful treatment of these diseases depends on biofilm removal as well as effective killing of biofilm bacteria. So, the fundamental to maintain oral health and prevent dental caries, gingivitis, and periodontitis is to control the oral biofilms. From these aspects, the formation of biofilms carries particular clinical significance because not only host defense mechanisms but also therapeutic efforts including chemical and mechanical antimicrobial treatment measures have the most difficult task of dealing with organisms that are gathered in a biofilm. The aim of this article was to review the mechanisms of biofilms’ formation, their roles in pulpal and periapical pathosis, the different types of biofilms, the factors influencing biofilm formation, the mechanisms of their antimicrobial resistance, techniques to

  17. Synergy in biofilm formation between Fusobacterium nucleatum and Prevotella species.

    Science.gov (United States)

    Okuda, Tamaki; Kokubu, Eitoyo; Kawana, Tomoko; Saito, Atsushi; Okuda, Katsuji; Ishihara, Kazuyuki

    2012-02-01

    The formation of biofilm by anaerobic, Gram-negative bacteria in the subgingival crevice plays an important role in the development of chronic periodontitis. The aim of this study was to characterize the role of coaggregation between Fusobacterium nucleatum and Prevotella species in biofilm formation. Coaggregation between F. nucleatum and Prevotella species was determined by visual assay. Effect of co-culture of the species on biofilm formation was assessed by crystal violet staining. Effect of soluble factor on biofilm formation was also examined using culture supernatant and two-compartment co-culture separated by a porous membrane. Production of autoinducer-2 (AI-2) by the organisms was evaluated using Vibrio harveyi BB170. Cells of all F. nucleatum strains coaggregated with Prevotella intermedia or Prevotella nigrescens with a score of 1-4. Addition of ethylenediamine tetraacetic acid or l-lysine inhibited coaggregation. Coaggregation disappeared after heating of P. intermedia or P. nigrescens cells, or Proteinase K treatment of P. nigrescens cells. Co-culture of F. nucleatum ATCC 25586 with P. intermedia or P. nigrescens strains increased biofilm formation compared with single culture (p culture with culture supernatant of these strains, however, did not enhance biofilm formation by F. nucleatum. Production of AI-2 in Prevotella species was not related to enhancement of biofilm formation by F. nucleatum. These findings indicate that physical contact by coaggregation of F. nucleatum strains with P. intermedia or P. nigrescens plays a key role in the formation of biofilm by these strains. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Inhibitory effect of Lactobacillus salivarius on Streptococcus mutans biofilm formation.

    Science.gov (United States)

    Wu, C-C; Lin, C-T; Wu, C-Y; Peng, W-S; Lee, M-J; Tsai, Y-C

    2015-02-01

    Dental caries arises from an imbalance of metabolic activities in dental biofilms developed primarily by Streptococcus mutans. This study was conducted to isolate potential oral probiotics with antagonistic activities against S. mutans biofilm formation from Lactobacillus salivarius, frequently found in human saliva. We analysed 64 L. salivarius strains and found that two, K35 and K43, significantly inhibited S. mutans biofilm formation with inhibitory activities more pronounced than those of Lactobacillus rhamnosus GG (LGG), a prototypical probiotic that shows anti-caries activity. Scanning electron microscopy showed that co-culture of S. mutans with K35 or K43 resulted in significantly reduced amounts of attached bacteria and network-like structures, typically comprising exopolysaccharides. Spot assay for S. mutans indicated that K35 and K43 strains possessed a stronger bactericidal activity against S. mutans than LGG. Moreover, quantitative real-time polymerase chain reaction showed that the expression of genes encoding glucosyltransferases, gtfB, gtfC, and gtfD was reduced when S. mutans were co-cultured with K35 or K43. However, LGG activated the expression of gtfB and gtfC, but did not influence the expression of gtfD in the co-culture. A transwell-based biofilm assay indicated that these lactobacilli inhibited S. mutans biofilm formation in a contact-independent manner. In conclusion, we identified two L. salivarius strains with inhibitory activities on the growth and expression of S. mutans virulence genes to reduce its biofilm formation. This is not a general characteristic of the species, so presents a potential strategy for in vivo alteration of plaque biofilm and caries. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  19. Rational Design and Synthesis of Biologically Active Disubstituted 2(3H) Furanones and Pyrrolone Derivatives as Potent and Safer Non Steroidal Anti-inflammatory Agents.

    Science.gov (United States)

    Khokra, S L; Khan, S A; Choudhary, D; Hasan, S M; Ahmad, A; Husain, Asif

    2016-01-01

    Furanone and pyrrolone heterocyclic ring system represent important and interesting classes of bioactive compounds. Medicinal chemists use these heterocycyclic moieties as scaffolds in drug design and discovery. A series of 3-arylidene-5-(naphthalene-2-yl)-furan-2(3H)-ones (2a-j) were synthesized by incorporating pharmacophore of COX-2 inhibitor rofecoxib and naphthyl ring of naproxen as potential non steroidal anti-inflammatory agents. These furanone derivatives were subsequently reacted with dry ammonia gas and benzylamine to furnish corresponding 3-arylidene-5-(naphthlen-2-yl)-1H-pyrrol-2(3H)-ones (3a-e) and 3-arylidene-1-benzyl-5- (naphthalene-2-yl)-1H-pyrrol-2(3H)-ones (4a-e), respectively. The newly prepared heterocyclics were screened for their expected in-vivo biological activities including anti-inflammatory, analgesic and ulcerogenic actions in rodents. The COX-2 inhibitory behavior of synthesized compounds was also assessed via automated docking studies. The chemical structure of the synthesized compounds was characterized by using modern spectroscopic techniques. Result of in-vivo pharmacological studies demonstrated that almost all N-Benzyl-pyrrol-2(3H)-ones (4a-e) showed better anti-inflammatory and analgesic activities in comparison with the other two series of furan-2(3H)-ones and pyrrol- 2(3H)-ones. The moldock score value of the tested compounds was found in the range of -116.66 to -170.328 and was better than the standard drug. Among all the synthesized compounds, only nine compounds (2d, 2g, 2h, 3d, 4a, 4b, 4c, 4d and 4e) exhibited potent anti-inflammatory and analgesic activities with significantly reduced gastrointestinal toxicity in various animal models in comparison to standard drug, diclofenac. Therefore, it is recommended to explore the potential of the synthesized compounds as lead candidates for the development of new therapeutic agents.

  20. Biofilm roughness determines Cryptosporidium parvum retention in environmental biofilms.

    Science.gov (United States)

    DiCesare, E A Wolyniak; Hargreaves, B R; Jellison, K L

    2012-06-01

    The genus Cryptosporidium is a group of waterborne protozoan parasites that have been implicated in significant outbreaks of gastrointestinal infections throughout the world. Biofilms trap these pathogens and can contaminate water supplies through subsequent release. Biofilm microbial assemblages were collected seasonally from three streams in eastern Pennsylvania and used to grow biofilms in laboratory microcosms. Daily oocyst counts in the influx and efflux flow allowed the calculation of daily oocyst retention in the biofilm. Following the removal of oocysts from the influx water, oocyst attachment to the biofilm declined to an equilibrium state within 5 days that was sustained for at least 25 days. Varying the oocyst loading rate for the system showed that biofilm retention could be saturated, suggesting that discrete binding sites determined the maximum number of oocysts retained. Oocyst retention varied seasonally but was consistent across all three sites; however, seasonal oocyst retention was not consistent across years at the same site. No correlation between oocyst attachment and any measured water quality parameter was found. However, oocyst retention was strongly correlated with biofilm surface roughness and roughness varied among seasons and across years. We hypothesize that biofilm roughness and oocyst retention are dependent on environmentally driven changes in the biofilm community rather than directly on water quality conditions. It is important to understand oocyst transport dynamics to reduce risks of human infection. Better understanding of factors controlling biofilm retention of oocysts should improve our understanding of oocyst transport at different scales.

  1. Anti-biofilm efficacy of low temperature processed AgCl–TiO{sub 2} nanocomposite coating

    Energy Technology Data Exchange (ETDEWEB)

    Naik, Kshipra, E-mail: kshipra_naik21@yahoo.co.in; Kowshik, Meenal, E-mail: meenal@goa.bits-pilani.ac.in

    2014-01-01

    Biofilms are a major concern in the medical settings and food industries due to their high tolerance to antibiotics, biocides and mechanical stress. Currently, the development of novel methods to control biofilm formation is being actively pursued. In the present study, sol–gel coatings of AgCl–TiO{sub 2} nanoparticles are presented as potential anti-biofilm agents, wherein TiO{sub 2} acts as a good supporting matrix to prevent aggregation of silver and facilitates its controlled release. Low-temperature processed AgCl–TiO{sub 2} nanocomposite coatings inhibit biofilm formation by Escherichia coli, Staphylococcus epidermidis and Pseudomonas aeruginosa. In vitro biofilm assay experiments demonstrated that AgCl–TiO{sub 2} nanocomposite coated surfaces, inhibited the development of biofilms over a period of 10 days as confirmed by scanning electron microscopy. The silver release kinetics exhibited an initial high release, followed by a slow and sustained release. The anti-biofilm efficacy of the coatings could be attributed to the release of silver, which prevents the initial bacterial adhesion required for biofilm formation. - Highlights: • Potential of AgCl–TiO{sub 2} nanocomposite coating to inhibit biofilm formation is exhibited. • Initial rapid release followed by later slow and sustained release of silver obtained. • TiO{sub 2} being porous and inorganic in nature acts as a good supporting matrix.

  2. Photo Inactivation of Streptococcus mutans Biofilm by Violet-Blue light.

    Science.gov (United States)

    Gomez, Grace F; Huang, Ruijie; MacPherson, Meoghan; Ferreira Zandona, Andrea G; Gregory, Richard L

    2016-09-01

    Among various preventive approaches, non-invasive phototherapy/photodynamic therapy is one of the methods used to control oral biofilm. Studies indicate that light at specific wavelengths has a potent antibacterial effect. The objective of this study was to determine the effectiveness of violet-blue light at 380-440 nm to inhibit biofilm formation of Streptococcus mutans or kill S. mutans. S. mutans UA159 biofilm cells were grown for 12-16 h in 96-well flat-bottom microtiter plates using tryptic soy broth (TSB) or TSB with 1 % sucrose (TSBS). Biofilm was irradiated with violet-blue light for 5 min. After exposure, plates were re-incubated at 37 °C for either 2 or 6 h to allow the bacteria to recover. A crystal violet biofilm assay was used to determine relative densities of the biofilm cells grown in TSB, but not in TSBS, exposed to violet-blue light. The results indicated a statistically significant (P mutans growth and reduce the formation of S. mutans biofilm. This in vitro study demonstrated that violet-blue light has the capacity to inhibit S. mutans biofilm formation. Potential clinical applications of light therapy in the future remain bright in preventing the development and progression of dental caries.

  3. PATHOGENICITY OF BIOFILM BACTERIA

    Science.gov (United States)

    There is a paucity of information concerning any link between the microorganisms commonly found in biofilms of drinking water systems and their impacts on human health. For bacteria, culture-based techniques detect only a limited number of the total microorganisms associated wit...

  4. [Biofilms in otolaryngology].

    Science.gov (United States)

    Mena Viveros, Nicolás

    2014-01-01

    According to the National Institute of Health of the USA, «more than 60% of all microbial infections are caused by biofilms».'This can surprise us, but it is enough to consider that common infections like those of the genito-urinary tract, infections produced by catheters, middle ear infections in children, the formation of dental plaque and gingivitis are caused by biofilms, for this statement to seem more realistic. At present this is one of the subjects of great interest within medicine, particularly in otolaryngology. Bacteria have traditionally been considered to be in a free state without evident organization, partly perhaps by the ease of studying them in this form. Nevertheless, the reality is that, in nature, the great majority of these germs form complex colonies adhered to surfaces, colonies that have received the name of biofilms. These biofilms are more common than previously thought and almost all of the people have been in contact with them in the form of infections in the teeth or humid, slippery areas. New treatments that can eradicate them are currently being investigated. Copyright © 2012 Elsevier España, S.L. All rights reserved.

  5. Antimicrobial Nisin Acts Against Saliva Derived Multi-Species Biofilms without Cytotoxicity to Human Oral Cells

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    Yvonne Lorraine Kapila

    2015-06-01

    Full Text Available Objectives: Nisin is a lantibiotic widely used for the preservation of food and beverages. Recently, investigators have reported that nisin may have clinical applications for treating bacterial infections. The aim of this study was to investigate the effects of ultra pure food grade Nisin ZP (> 95% purity on taxonomically diverse bacteria common to the human oral cavity and saliva derived multi-species oral biofilms, and to discern the toxicity of nisin against human cells relevant to the oral cavity. Methods: The MICs and MBCs of taxonomically distinct oral bacteria were determined using agar and broth dilution methods. To assess the effects of nisin on biofilms, two model systems were utilized: a static and a controlled flow microfluidic system. Biofilms were inoculated with pooled human saliva and fed filter-sterilized saliva for 20-22 h at 37°C. Nisin effects on cellular apoptosis and proliferation were evaluated using acridine orange/ethidium bromide fluorescent nuclear staining and lactate dehydrogenase activity assays. Results: Nisin inhibited planktonic growth of oral bacteria at low concentrations (2.5 – 50 μg/ml. Nisin also retarded development of multi-species biofilms at concentrations ≥ 1 μg/ml. Specifically, under biofilm model conditions, nisin interfered with biofilm development and reduced biofilm biomass and thickness in a dose-dependent manner. The treatment of pre-formed biofilms with nisin resulted in dose- and time-dependent disruption of the biofilm architecture along with decreased bacterial viability. Human cells relevant to the oral cavity were unaffected by the treatment of nisin at anti-biofilm concentrations and showed no signs of apoptotic changes unless treated with much higher concentrations (> 200 μg/ml. Conclusions: This work highlights the potential therapeutic value of high purity food grade nisin to inhibit the growth of oral bacteria and the development of biofilms relevant to oral diseases.

  6. Inhibitory effect of zinc oxide nanoparticles on pseudomonas aeruginosa biofilm formation

    Directory of Open Access Journals (Sweden)

    Mohammad Hassani Sangani

    2015-04-01

    Full Text Available Objective(s: Bacterial biofilm formation causes many persistent and chronic infections. The matrix protects biofilm bacteria from exposure to innate immune defenses and antibiotic treatments. The purpose of this study was to evaluate the biofilm formation of clinical isolates of Pseudomonas aeruginosa and the activity of zinc oxide nanoparticles (ZnO NPs on biofilm. Materials and Methods: After collecting bacteria from clinical samples of hospitalized patients, the ability of organisms were evaluated to create biofilm by tissue culture plate (TCP assay. ZnO NPs were synthesized by sol gel method and the efficacy of different concentrations (50- 350 µg/ml of ZnO NPs was assessed on biofilm formation and also elimination of pre-formed biofilm by using TCP method. Results:The average diameter of synthesized ZnO NPs was 20 nm. The minimum inhibitory concentration of nanoparticles was 150- 158 μg/ml and the minimum bactericidal concentration was higher (325 µg/ml. All 15 clinical isolates of P. aeruginosa were able to produce biofilm. Treating the organisms with nanoparticles at concentrations of 350 μg/ml resulted in more than 94% inhibition in OD reduction%. Molecular analysis showed that the presence of mRNA of pslA gene after treating bacteria with ZnO NPs for 30 minutes. Conclusion: The results showed that ZnO NPs can inhibit the establishment of P. aeruginosa biofilms and have less effective in removing pre-formed biofilm. However the tested nanoparticles exhibited anti-biofilm effect, but mRNA of pslA gene could be still detected in the medium by RT-PCR technique after 30 minutes treatment with ZnO.

  7. Effects of Subinhibitory Concentrations of Ceftaroline on Methicillin-Resistant Staphylococcus aureus (MRSA Biofilms.

    Directory of Open Access Journals (Sweden)

    María Lázaro-Díez

    Full Text Available Ceftaroline (CPT is a novel cephalosporin with in vitro activity against Staphylococcus aureus. Ceftaroline exhibits a level of binding affinity for PBPs in S. aureus including PBP2a of methicillin-resistant S. aureus (MRSA. The aims of this study were to investigate the morphological, physiological and molecular responses of MRSA clinical strains and MRSA biofilms to sub-MICs (1/4 and 1/16 MIC of ceftaroline by using transmission, scanning and confocal microscopy. We have also used quantitative Real-Time PCR to study the effect of sub-MICs of ceftaroline on the expression of the staphylococcal icaA, agrA, sarA and sasF genes in MRSA biofilms. In one set of experiments, ceftaroline was able to inhibit biofilm formation in all strains tested at MIC, however, a strain dependent behavior in presence of sub-MICs of ceftaroline was shown. In a second set of experiments, destruction of preformed biofilms by addition of ceftaroline was evaluated. Ceftaroline was able to inhibit biofilm formation at MIC in all strains tested but not at the sub-MICs. Destruction of preformed biofilms was strain dependent because the biofilm formed by a matrix-producing strain was resistant to a challenge with ceftaroline at MIC, whereas in other strains the biofilm was sensitive. At sub-MICs, the impact of ceftaroline on expression of virulence genes was strain-dependent at 1/4 MIC and no correlation between ceftaroline-enhanced biofilm formation and gene regulation was established at 1/16 MIC. Our findings suggest that sub-MICs of ceftaroline enhance bacterial attachment and biofilm formation by some, but not all, MRSA strains and, therefore, stress the importance of maintaining effective bactericidal concentrations of ceftaroline to fight biofilm-MRSA related infections.

  8. Effect of biosurfactants on Pseudomonas aeruginosa and Staphylococcus aureus biofilms in a BioFlux channel.

    Science.gov (United States)

    Diaz De Rienzo, M A; Stevenson, P S; Marchant, R; Banat, I M

    2016-07-01

    Recent studies have indicated that biosurfactants play a role both in maintaining channels between multicellular structures in biofilms and in dispersal of cells from biofilms. A combination of caprylic acid (0.01 % v/v) together with rhamnolipids (0.04 % v/v) was applied to biofilms of Pseudomonas aeruginosa ATCC 15442, Staphylococcus aureus ATCC 9144 and a mixed culture under BioFlux flowthrough conditions and caused disruption of the biofilms. The biofilms were also treated with a combination of rhamnolipids (0.04 % v/v) and sophorolipids (0.01 %). Control treatments with PBS 1× had no apparent effect on biofilm disruption. The Gram-positive bacterium (S. aureus ATCC 9144) was more sensitive than P. aeruginosa ATCC 15442 in terms of disruption and viability as shown by Live/Dead staining. Disruption of biofilms of P. aeruginosa ATCC 15442 was minimal. Oxygen consumption by biofilms, after different treatments with biosurfactants, confirms that sophorolipid on its own is unable to kill/inhibit cells of P. aeruginosa ATCC 15442, and even when used in combination with rhamnolipids, under static conditions, no decrease in the cell viability was observed. Cells in biofilms exposed to mono-rhamnolipids (0.04 % v/v) showed behaviour typical of exposure to bacteriostatic compounds, but when exposed to di-rhamnolipids (0.04 % v/v), they displayed a pattern characteristic of bactericidal compounds.

  9. Long alkyl-chain imidazolium ionic liquids: Antibiofilm activity against phototrophic biofilms.

    Science.gov (United States)

    Reddy, G Kiran Kumar; Nancharaiah, Y V; Venugopalan, V P

    2017-07-01

    Biofilm formation is problematic and hence undesirable in medical and industrial settings. In addition to bacteria, phototrophic organisms are an integral component of biofilms that develop on surfaces immersed in natural waters. 1-Alkyl-3-methyl imidazolium ionic liquids (IL) with varying alkyl chain length were evaluated for their influence on the formation of monospecies (Navicula sp.) and multispecies biofilms under phototrophic conditions. An IL with a long alkyl side chain, 1-hexadecyl-3-methylimidaazolium chloride ([C 16 (MIM)][Cl]) retarded growth, adhesion and biofilm formation of Navicula sp. at concentrations as low as 5μM. Interestingly, [C 16 (MIM)][Cl] was very effective in preventing multispecies phototrophic biofilms on fibre reinforced plastic surfaces immersed in natural waters (fresh and seawater). SYTOX ® Green staining and chlorophyll leakage assay confirmed that the biocidal activity of the IL was exerted through cell membrane disruption. The data show that [C 16 (MIM)][Cl] is a potent inhibitor of phototrophic biofilms at micromolar concentrations and a promising agent for biofilm control in re-circulating cooling water systems. This is the first report that ionic liquids inhibit biofilm formation by phototrophic organisms which are important members of biofilms in streams and cooling towers. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Effect of γ-lactones and γ-lactams compounds on Streptococcus mutans biofilms

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    Mariane Beatriz Sordi

    2018-02-01

    Full Text Available Abstract Considering oral diseases, antibiofilm compounds can decrease the accumulation of pathogenic species such as Streptococcus mutans at micro-areas of teeth, dental restorations or implant-supported prostheses. Objective To assess the effect of thirteen different novel lactam-based compounds on the inhibition of S. mutans biofilm formation. Material and methods We synthesized compounds based on γ-lactones analogues from rubrolides by a mucochloric acid process and converted them into their corresponding γ-hydroxy-γ-lactams by a reaction with isobutylamine and propylamine. Compounds concentrations ranging from 0.17 up to 87.5 μg mL-1 were tested against S. mutans. We diluted the exponential cultures in TSB and incubated them (37°C in the presence of different γ-lactones or γ-lactams dilutions. Afterwards, we measured the planktonic growth by optical density at 630 nm and therefore assessed the biofilm density by the crystal violet staining method. Results Twelve compounds were active against biofilm formation, showing no effect on bacterial viability. Only one compound was inactive against both planktonic and biofilm growth. The highest biofilm inhibition (inhibition rate above 60% was obtained for two compounds while three other compounds revealed an inhibition rate above 40%. Conclusions Twelve of the thirteen compounds revealed effective inhibition of S. mutans biofilm formation, with eight of them showing a specific antibiofilm effect.

  11. Inhibitory Effect of Lactococcus lactis HY 449 on Cariogenic Biofilm.

    Science.gov (United States)

    Kim, Young-Jae; Lee, Sung-Hoon

    2016-11-28

    Dental caries is caused by cariogenic biofilm, an oral biofilm including Streptococcus mutans . Recently, the prevention of dental caries using various probiotics has been attempted. Lactococcus lactis HY 449 is a probiotic bacterium. The aim of this study was to investigate the effect of L. lactis HY 449 on cariogenic biofilm and to analyze its inhibitory mechanisms. Cariogenic biofilm was formed in the presence or absence of L. lactis HY 449 and L. lactis ATCC 19435, and analyzed with a confocal laser microscope. The formation of cariogenic biofilm was reduced in cultures spiked with both L. lactis strains, and L. lactis HY 449 exhibited more inhibitory effects than L. lactis ATCC 19435. In order to analyze and to compare the inhibitory mechanisms, the antibacterial activity of the spent culture medium from both L. lactis strains against S. mutans was investigated, and the expression of glucosyltransferases ( gtfs ) of S. mutans was then analyzed by real-time RT-PCR. In addition, the sucrose fermentation ability of both L. lactis strains was examined. Both L. lactis strains showed antibacterial activity and inhibited the expression of gtfs , and the difference between both strains did not show. In the case of sucrose-fermenting ability, L. lactis HY 449 fermented sucrose but L. lactis ATCC 19435 did not. L. lactis HY 449 inhibited the uptake of sucrose and the gtfs expression of S. mutans , whereby the development of cariogenic biofilm may be inhibited. In conclusion, L. lactis HY 449 may be a useful probiotic for the prevention of dental caries.

  12. Lipidomics of Candida albicans biofilms reveals phase-dependent production of phospholipid molecular classes and role for lipid rafts in biofilm formation.

    Science.gov (United States)

    Lattif, Ali Abdul; Mukherjee, Pranab K; Chandra, Jyotsna; Roth, Mary R; Welti, Ruth; Rouabhia, Mahmoud; Ghannoum, Mahmoud A

    2011-11-01

    Candida albicans-associated bloodstream infections are linked to the ability of this yeast to form biofilms. In this study, we used lipidomics to compare the lipid profiles of C. albicans biofilms and planktonic cells, in early and mature developmental phases. Our results showed that significant differences exist in lipid composition in both developmental phases. Biofilms contained higher levels of phospholipid and sphingolipids than planktonic cells (nmol per g biomass, Pbiofilms compared to planktonic cells (P≤0.05). The ratio of phosphatidylcholine to phosphatidylethanolamine was lower in biofilms compared to planktonic cells in both early (1.17 vs 2.52, P≤0.001) and late (2.34 vs 3.81, P≤0.001) developmental phases. The unsaturation index of phospholipids decreased with time, with this effect being particularly strong for biofilms. Inhibition of the biosynthetic pathway for sphingolipid [mannosyl diinositolphosphoryl ceramide, M(IP)₂C] by myriocin or aureobasidin A, and disruption of the gene encoding inositolphosphotransferase (Ipt1p), abrogated the ability of C. albicans to form biofilms. The differences in lipid profiles between biofilms and planktonic Candida cells may have important implications for the biology and antifungal resistance of biofilms.

  13. Chitosan-propolis nanoparticle formulation demonstrates anti-bacterial activity against Enterococcus faecalis biofilms.

    Directory of Open Access Journals (Sweden)

    Teik Hwa Ong

    Full Text Available Propolis obtained from bee hives is a natural substance with antimicrobial properties. It is limited by its insolubility in aqueous solutions; hence ethanol and ethyl acetate extracts of Malaysian propolis were prepared. Both the extracts displayed antimicrobial and anti-biofilm properties against Enterococcus faecalis, a common bacterium associated with hospital-acquired infections. High performance liquid chromatography (HPLC analysis of propolis revealed the presence of flavonoids like kaempferol and pinocembrin. This study investigated the role of propolis developed into nanoparticles with chitosan for its antimicrobial and anti-biofilm properties against E. faecalis. Bacteria that grow in a slimy layer of biofilm are resistant to penetration by antibacterial agents. The use of nanoparticles in medicine has received attention recently due to better bioavailability, enhanced penetrative capacity and improved efficacy. A chitosan-propolis nanoformulation was chosen based on ideal physicochemical properties such as particle size, zeta potential, polydispersity index, encapsulation efficiency and the rate of release of the active ingredients. This formulation inhibited E. faecalis biofilm formation and reduced the number of bacteria in the biofilm by ~90% at 200 μg/ml concentration. When tested on pre-formed biofilms, the formulation reduced bacterial number in the biofilm by ~40% and ~75% at 200 and 300 μg/ml, respectively. The formulation not only reduced bacterial numbers, but also physically disrupted the biofilm structure as observed by scanning electron microscopy. Treatment of biofilms with chitosan-propolis nanoparticles altered the expression of biofilm-associated genes in E. faecalis. The results of this study revealed that chitosan-propolis nanoformulation can be deemed as a potential anti-biofilm agent in resisting infections involving biofilm formation like chronic wounds and surgical site infections.

  14. Anti-biofilm activities from marine cold adapted bacteria against staphylococci and Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Rosanna ePapa

    2015-12-01

    Full Text Available Microbial biofilms have great negative impacts on the world’s economy and pose serious problems to industry, public health and medicine. The interest in the development of new approaches for the prevention and treatment of bacterial adhesion and biofilm formation has increased. Since, bacterial pathogens living in biofilm induce persistent chronic infections due to the resistance to antibiotics and host immune system. A viable approach should target adhesive properties without affecting bacterial vitality in order to avoid the appearance of resistant mutants. Many bacteria secrete anti-biofilm molecules that function in regulating biofilm architecture or mediating the release of cells from it during the dispersal stage of biofilm life cycle. Cold-adapted marine bacteria represent an untapped reservoir of biodiversity able to synthesize a broad range of bioactive compounds, including anti-biofilm molecules.The anti-biofilm activity of cell-free supernatants derived from sessile and planktonic cultures of cold-adapted bacteria belonging to Pseudoalteromonas, Psychrobacter and Psychromonas species were tested against Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa strains. Reported results demonstrate that we have selected supernatants, from cold-adapted marine bacteria, containing non-biocidal agents able to destabilize biofilm matrix of all tested pathogens without killing cells. A preliminary physico-chemical characterization of supernatants was also performed, and these analyses highlighted the presence of molecules of different nature that act by inhibiting biofilm formation. Some of them are also able to impair the initial attachment of the bacterial cells to the surface, thus likely containing molecules acting as anti-biofilm surfactant molecules.The described ability of cold-adapted bacteria to produce effective anti-biofilm molecules paves the way to further characterization of the most promising molecules

  15. The Extracellular Matrix of Candida albicans Biofilms Impairs Formation of Neutrophil Extracellular Traps.

    Science.gov (United States)

    Johnson, Chad J; Cabezas-Olcoz, Jonathan; Kernien, John F; Wang, Steven X; Beebe, David J; Huttenlocher, Anna; Ansari, Hamayail; Nett, Jeniel E

    2016-09-01

    Neutrophils release extracellular traps (NETs) in response to planktonic C. albicans. These complexes composed of DNA, histones, and proteins inhibit Candida growth and dissemination. Considering the resilience of Candida biofilms to host defenses, we examined the neutrophil response to C. albicans during biofilm growth. In contrast to planktonic C. albicans, biofilms triggered negligible release of NETs. Time lapse imaging confirmed the impairment in NET release and revealed neutrophils adhering to hyphae and migrating on the biofilm. NET inhibition depended on an intact extracellular biofilm matrix as physical or genetic disruption of this component resulted in NET release. Biofilm inhibition of NETosis could not be overcome by protein kinase C activation via phorbol myristate acetate (PMA) and was associated with suppression of neutrophil reactive oxygen species (ROS) production. The degree of impaired NET release correlated with resistance to neutrophil attack. The clinical relevance of the role for extracellular matrix in diminishing NET production was corroborated in vivo using a rat catheter model. The C. albicans pmr1Δ/Δ, defective in production of matrix mannan, appeared to elicit a greater abundance of NETs by scanning electron microscopy imaging, which correlated with a decreased fungal burden. Together, these findings show that C. albicans biofilms impair neutrophil response through an inhibitory pathway induced by the extracellular matrix.

  16. Eco-friendly fabrication of Ag nanostructures using the seed extract of Pedalium murex, an ancient Indian medicinal plant: Histopathological effects on the Zika virus vector Aedes aegypti and inhibition of biofilm-forming pathogenic bacteria.

    Science.gov (United States)

    Ishwarya, Ramachandran; Vaseeharan, Baskaralingam; Anuradha, Ramasamy; Rekha, Ravichandran; Govindarajan, Marimuthu; Alharbi, Naiyf S; Kadaikunnan, Shine; Khaled, Jamal M; Benelli, Giovanni

    2017-09-01

    The control of Zika virus mosquito vectors and well as the development of drugs in the fight against biofilm-forming microbial pathogens, are timely and important challenges in current bionanoscience. Here we focused on the eco-friendly fabrication of Ag nanostructures using the seed extract of Pedalium murex, an ancient Indian medicinal plant. Initial confirmation of Ag nanoparticles (AgNPs) production was showed by a color change from transparent to dark brown. The UV-Visible spectrum (476nm), X-ray diffraction peaks (101, 200, 220 and 311) and Fourier transform infrared spectroscopy shed light on the production of green-capped AgNPs. Morphological structure analysis using HR-TEM showed that the AgNPs were mostly hexagonal in shape with rough edges, and a size of 20-30nm. The larvicidal potential of P. murex seed extract and AgNPs fabricated using the P. murex seed extract (Pm-AgNPs) was tested on fourth instar mosquito larvae of the Zika virus vector Aedes aegypti. Maximum efficacy was achieved by Pm-AgNPs against Ae. aegypti after 24h (LC 50 34.88; LC 90 64.56mg/ml), if compared to the P. murex seed extract. Histopathological analyses showed severe damages to the hindgut and larval muscles in NPs-treated Ae. aegypti larvae. The sub-MIC concentrations of Pm-AgNPs exhibited significant anti-biofilm activity against Gram positive (Enterococcus faecalis, Staphylococcus aureus) and Gram negative (Shigella sonnei, Pseudomonas aeruginosa) bacterial pathogens, as showed by EPS and MTP assays. Light and CLSM microscopic studies highlighted a significant impact of P. murex seed extract and Pm-synthesized AgNPs on the surface topography and architecture of bacterial biofilm, both in Gram positive and Gram negative species. Overall, results reported here contribute to the development of reliable large-scale protocols for the green fabrication of effective mosquito larvicides and biofilm inhibitors. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. New Weapons to Fight Old Enemies: Novel Strategies for the (Bio)control of Bacterial Biofilms in the Food Industry.

    Science.gov (United States)

    Coughlan, Laura M; Cotter, Paul D; Hill, Colin; Alvarez-Ordóñez, Avelino

    2016-01-01

    Biofilms are microbial communities characterized by their adhesion to solid surfaces and the production of a matrix of exopolymeric substances, consisting of polysaccharides, proteins, DNA and lipids, which surround the microorganisms lending structural integrity and a unique biochemical profile to the biofilm. Biofilm formation enhances the ability of the producer/s to persist in a given environment. Pathogenic and spoilage bacterial species capable of forming biofilms are a significant problem for the healthcare and food industries, as their biofilm-forming ability protects them from common cleaning processes and allows them to remain in the environment post-sanitation. In the food industry, persistent bacteria colonize the inside of mixing tanks, vats and tubing, compromising food safety and quality. Strategies to overcome bacterial persistence through inhibition of biofilm formation or removal of mature biofilms are therefore necessary. Current biofilm control strategies employed in the food industry (cleaning and disinfection, material selection and surface preconditioning, plasma treatment, ultrasonication, etc.), although effective to a certain point, fall short of biofilm control. Efforts have been explored, mainly with a view to their application in pharmaceutical and healthcare settings, which focus on targeting molecular determinants regulating biofilm formation. Their application to the food industry would greatly aid efforts to eradicate undesirable bacteria from food processing environments and, ultimately, from food products. These approaches, in contrast to bactericidal approaches, exert less selective pressure which in turn would reduce the likelihood of resistance development. A particularly interesting strategy targets quorum sensing systems, which regulate gene expression in response to fluctuations in cell-population density governing essential cellular processes including biofilm formation. This review article discusses the problems associated

  18. New weapons to fight old enemies: novel strategies for the (biocontrol of bacterial biofilms in the food industry

    Directory of Open Access Journals (Sweden)

    Laura Maria Coughlan

    2016-10-01

    Full Text Available Biofilms are microbial communities characterized by their adhesion to solid surfaces and the production of a matrix of exopolymeric substances (EPS, consisting of polysaccharides, proteins, DNA and lipids, which surround the microorganisms lending structural integrity and a unique biochemical profile to the biofilm. Biofilm formation enhances the ability of the producer/s to persist in a given environment. Pathogenic and spoilage bacterial species capable of forming biofilms are a significant problem for the healthcare and food industries, as their biofilm-forming ability protects them from common cleaning processes and allows them to remain in the environment post-sanitation. In the food industry, persistent bacteria colonize the inside of mixing tanks, vats and tubing, compromising food safety and quality. Strategies to overcome bacterial persistence through inhibition of biofilm formation or removal of mature biofilms are therefore necessary. Current biofilm control strategies employed in the food industry (cleaning and disinfection, material selection and surface preconditioning, plasma treatment, ultrasonication, etc., although effective to a certain point, fall short of biofilm control. Efforts have been explored, mainly with a view to their application in pharmaceutical and healthcare settings, which focus on targeting molecular determinants regulating biofilm formation. Their application to the food industry would greatly aid efforts to eradicate undesirable bacteria from food processing environments and, ultimately, from food products. These approaches, in contrast to bactericidal approaches, exert less selective pressure which in turn would reduce the likelihood of resistance development. A particularly interesting strategy targets quorum sensing systems, which regulate gene expression in response to fluctuations in cell-population density governing essential cellular processes including biofilm formation. This review article discusses

  19. Anti-biofilm Properties of the Fecal Probiotic Lactobacilli Against Vibrio spp.

    Directory of Open Access Journals (Sweden)

    Sumanpreet Kaur

    2018-04-01

    Full Text Available Diarrheal disease caused by Vibrio cholerae is endemic in developing countries including India and is associated with high rate of mortality especially in children. V. cholerae is known to form biofilms on the gut epithelium, and the biofilms once formed are resistant to the action of antibiotics. Therefore agents that prevent the biofilm formation and disperse the preformed biofilms are associated with therapeutic benefits. The use of antibiotics for the treatment of cholera is associated with side effects such as gut dysbiosis due to depletion of gut microflora, and the increasing problem of antibiotic resistance. Thus search for safe alternative therapeutic agents is warranted. Herein, we screened the lactobacilli spp. isolated from the fecal samples of healthy children for their abilities to prevent biofilm formation and to disperse the preformed biofilms of V. cholerae and V. parahaemolyticus by using an in vitro assay. The results showed that the culture supernatant (CS of all the seven isolates of Lactobacillus spp. used in the study inhibited the biofilm formation of V. cholerae by more than 90%. Neutralization of pH of CS completely abrogated their antimicrobial activities against V. cholera, but had negligible effects on their biofilm inhibitory potential. Further, CS of all the lactobacilli isolates caused the dispersion of preformed V. cholerae biofilms in the range 62–85%; however, pH neutralization of CS reduced the biofilm dispersal potential of the 4 out of 7 isolates by 19–57%. Furthermore, the studies showed that CS of none of the lactobacilii isolates had antimicrobial activity against V. parahaemolyticus, but 5 out of 7 isolates inhibited the formation of its biofilm in the range 62–82%. However, none of the CS dispersed the preformed biofilms of V. parahaemolyticus. The ability of CS to inhibit the adherence of Vibrio spp. to the epithelial cell line was also determined. Thus, we conclude that the biofilm dispersive

  20. New Technologies for Studying Biofilms

    Science.gov (United States)

    FRANKLIN, MICHAEL J.; CHANG, CONNIE; AKIYAMA, TATSUYA; BOTHNER, BRIAN

    2016-01-01

    Bacteria have traditionally been studied as single-cell organisms. In laboratory settings, aerobic bacteria are usually cultured in aerated flasks, where the cells are considered essentially homogenous. However, in many natural environments, bacteria and other microorganisms grow in mixed communities, often associated with surfaces. Biofilms are comprised of surface-associated microorganisms, their extracellular matrix material, and environmental chemicals that have adsorbed to the bacteria or their matrix material. While this definition of a biofilm is fairly simple, biofilms are complex and dynamic. Our understanding of the activities of individual biofilm cells and whole biofilm systems has developed rapidly, due in part to advances in molecular, analytical, and imaging tools and the miniaturization of tools designed to characterize biofilms at the enzyme level, cellular level, and systems level. PMID:26350329

  1. Silver against Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Kirketerp-Møller, K.; Kristiansen, S.

    2007-01-01

    bacteria in both the planktonic and biofilm modes of growth. The action of silver on mature in vitro biofilms of Pseudomonas aeruginosa, a primary pathogen of chronic infected wounds, was investigated. The results show that silver is very effective against mature biofilms of P. aeruginosa......, but that the silver concentration is important. A concentration of 5-10 ig/mL silver sulfadiazine eradicated the biofilm whereas a lower concentration (1 ig/mL) had no effect. The bactericidal concentration of silver required to eradicate the bacterial biofilm was 10-100 times higher than that used to eradicate...... planktonic bacteria. These observations strongly indicate that the concentration of silver in currently available wound dressings is much too low for treatment of chronic biofilm wounds. It is suggested that clinicians and manufacturers of the said wound dressings consider whether they are treating wounds...

  2. Metabolic activity, urease production, antibiotic resistance and virulence in dual species biofilms of Staphylococcus epidermidis and Staphylococcus aureus

    Science.gov (United States)

    Vandecandelaere, Ilse; Van Nieuwerburgh, Filip; Deforce, Dieter

    2017-01-01

    In this paper, the metabolic activity in single and dual species biofilms of Staphylococcus epidermidis and Staphylococcus aureus isolates was investigated. Our results demonstrated that there was less metabolic activity in dual species biofilms compared to S. aureus biofilms. However, this was not observed if S. aureus and S. epidermidis were obtained from the same sample. The largest effect on metabolic activity was observed in biofilms of S. aureus Mu50 and S. epidermidis ET-024. A transcriptomic analysis of these dual species biofilms showed that urease genes and genes encoding proteins involved in metabolism were downregulated in comparison to monospecies biofilms. These results were subsequently confirmed by phenotypic assays. As metabolic activity is related to acid production, the pH in dual species biofilms was slightly higher compared to S. aureus Mu50 biofilms. Our results showed that S. epidermidis ET-024 in dual species biofilms inhibits metabolic activity of S. aureus Mu50, leading to less acid production. As a consequence, less urease activity is required to compensate for low pH. Importantly, this effect was biofilm-specific. Also S. aureus Mu50 genes encoding virulence-associated proteins (Spa, SplF and Dps) were upregulated in dual species biofilms compared to monospecies biofilms and using Caenorhabditis elegans infection assays, we demonstrated that more nematodes survived when co-infected with S. epidermidis ET-024 and S. aureus mutants lacking functional spa, splF or dps genes, compared to nematodes infected with S. epidermidis ET-024 and wild- type S. aureus. Finally, S. epidermidis ET-024 genes encoding resistance to oxacillin, erythromycin and tobramycin were upregulated in dual species biofilms and increased resistance was subsequently confirmed. Our data indicate that both species in dual species biofilms of S. epidermidis and S. aureus influence each other’s behavior, but additional studies are required necessary to elucidate the exact

  3. Extracellular DNA Contributes to Dental Biofilm Stability

    DEFF Research Database (Denmark)

    Schlafer, Sebastian; Meyer, Rikke Louise; Dige, Irene

    2017-01-01

    dental biofilms. This study aimed to determine whether eDNA was part of the matrix in biofilms grown in situ in the absence of sucrose and whether treatment with DNase dispersed biofilms grown for 2.5, 5, 7.5, 16.5, or 24 h. Three hundred biofilms from 10 study participants were collected and treated...... the amount of biofilm in very early stages of growth (up to 7.5 h), but the treatment effect decreased with increasing biofilm age. This study proves the involvement of eDNA in dental biofilm formation and its importance for biofilm stability in the earliest stages. Further research is required to uncover...

  4. Potential of a lytic bacteriophage to disrupt Acinetobacter baumannii biofilms in vitro.

    Science.gov (United States)

    Liu, Yannan; Mi, Zhiqiang; Niu, Wenkai; An, Xiaoping; Yuan, Xin; Liu, Huiying; Wang, Yong; Feng, Yuzhong; Huang, Yong; Zhang, Xianglilan; Zhang, Zhiyi; Fan, Hang; Peng, Fan; Li, Puyuan; Tong, Yigang; Bai, Changqing

    2016-10-01

    The ability of Acinetobacter baumannii to form biofilms and develop antibiotic resistance makes it difficult to control infections caused by this bacterium. In this study, we explored the potential of a lytic bacteriophage to disrupt A. baumannii biofilms. The potential of the lytic bacteriophage to disrupt A. baumannii biofilms was assessed by performing electron microscopy, live/dead bacterial staining, crystal violet staining and by determining adenosine triphosphate release. The bacteriophage inhibited the formation of and disrupted preformed A. baumannii biofilms. Results of disinfection assay showed that the lytic bacteriophage lysed A. baumannii cells suspended in blood or grown on metal surfaces. These results suggest the potential of the lytic bacteriophage to disrupt A. baumannii biofilms.

  5. Biofilm and Dental Biomaterials

    Directory of Open Access Journals (Sweden)

    Marit Øilo

    2015-05-01

    Full Text Available All treatment involving the use of biomaterials in the body can affect the host in positive or negative ways. The microbiological environment in the oral cavity is affected by the composition and shape of the biomaterials used for oral restorations. This may impair the patients’ oral health and sometimes their general health as well. Many factors determine the composition of the microbiota and the formation of biofilm in relation to biomaterials such as, surface roughness, surface energy and chemical composition, This paper aims to give an overview of the scientific literature regarding the association between the chemical, mechanical and physical properties of dental biomaterials and oral biofilm formation, with emphasis on current research and future perspectives.

  6. Modern techniques for studying biofilm-influenced corrosion

    International Nuclear Information System (INIS)

    Beech, I.B.

    1998-01-01

    In natural and made-made environments the presence of biofilms on surfaces of metals and their alloys influences electrochemistry at the biofilm/substratum interface, enhancing or inhibiting corrosion reactions. Due to the complexity of the biocorrosion phenomenon a range of techniques is commonly employed to study mechanisms involved. In addition to traditional methods of corrosion investigation such as electrochemical measurements and light and scanning electron microscopy observations coupled with energy dispersive X-ray analysis (EDXA) and X-ray diffraction (XRD). Modern techniques of surface science proved to be very useful in elucidating biofilm/metal interactions. Recent applications of Environmental Scanning Electron Microscopy (ESEM), Atomic Force Microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) to biocorrosion studies allowed better understanding of the biologically influenced metal deterioration process. The scope and promise of these latter techniques will be discussed and their use illustrated on practical examples. (Author)

  7. Biofilms promote altruism.

    Science.gov (United States)

    Kreft, Jan-Ulrich

    2004-08-01

    The origin of altruism is a fundamental problem in evolution, and the maintenance of biodiversity is a fundamental problem in ecology. These two problems combine with the fundamental microbiological question of whether it is always advantageous for a unicellular organism to grow as fast as possible. The common basis for these three themes is a trade-off between growth rate and growth yield, which in turn is based on irreversible thermodynamics. The trade-off creates an evolutionary alternative between two strategies: high growth yield at low growth rate versus high growth rate at low growth yield. High growth yield at low growth rate is a case of an altruistic strategy because it increases the fitness of the group by using resources economically at the cost of decreased fitness, or growth rate, of the individual. The group-beneficial behaviour is advantageous in the long term, whereas the high growth rate strategy is advantageous in the short term. Coexistence of species requires differences between their niches, and niche space is typically divided into four 'axes' (time, space, resources, predators). This neglects survival strategies based on cooperation, which extend the possibilities of coexistence, arguing for the inclusion of cooperation as the fifth 'axis'. Here, individual-based model simulations show that spatial structure, as in, for example, biofilms, is necessary for the origin and maintenance of this 'primitive' altruistic strategy and that the common belief that growth rate but not yield decides the outcome of competition is based on chemostat models and experiments. This evolutionary perspective on life in biofilms can explain long-known biofilm characteristics, such as the structural organization into microcolonies, the often-observed lack of mixing among microcolonies, and the shedding of single cells, as promoting the origin and maintenance of the altruistic strategy. Whereas biofilms enrich altruists, enrichment cultures, microbiology's paradigm

  8. [Bacterial biofilms and infection].

    Science.gov (United States)

    Lasa, I; Del Pozo, J L; Penadés, J R; Leiva, J

    2005-01-01

    In developed countries we tend to think of heart disease and the numerous forms of cancer as the main causes of mortality, but on a global scale infectious diseases come close, or may even be ahead: 14.9 million deaths in 2002 compared to cardiovascular diseases (16.9 million deaths) and cancer (7.1 million deaths) (WHO report 2004). The infectious agents responsible for human mortality have evolved as medical techniques and hygienic measures have changed. Modern-day acute infectious diseases caused by specialized bacterial pathogens such as diphtheria, tetanus, cholera, plague, which represented the main causes of death at the beginning of XX century, have been effectively controlled with antibiotics and vaccines. In their place, more than half of the infectious diseases that affect mildly immunocompromised patients involve bacterial species that are commensal with the human body; these can produce chronic infections, are resistant to antimicrobial agents and there is no effective vaccine against them. Examples of these infections are the otitis media, native valve endocarditis, chronic urinary infections, bacterial prostatitis, osteomyelitis and all the infections related to medical devices. Direct analysis of the surface of medical devices or of tissues that have been foci of chronic infections shows the presence of large numbers of bacteria surrounded by an exopolysaccharide matrix, which has been named the "biofilm". Inside the biofilm, bacteria grow protected from the action of the antibodies, phagocytic cells and antimicrobial treatments. In this article, we describe the role of bacterial biofilms in human persistent infections.

  9. Biofilm attachment reduction on bioinspired, dynamic, micro-wrinkling surfaces

    International Nuclear Information System (INIS)

    Epstein, Alexander K; Hong, Donggyoon; Kim, Philseok; Aizenberg, Joanna

    2013-01-01

    Most bacteria live in multicellular communities known as biofilms that are adherent to surfaces in our environment, from sea beds to plumbing systems. Biofilms are often associated with clinical infections, nosocomial deaths and industrial damage such as bio-corrosion and clogging of pipes. As mature biofilms are extremely challenging to eradicate once formed, prevention is advantageous over treatment. However, conventional surface chemistry strategies are either generally transient, due to chemical masking, or toxic, as in the case of leaching marine antifouling paints. Inspired by the nonfouling skins of echinoderms and other marine organisms, which possess highly dynamic surface structures that mechanically frustrate bio-attachment, we have developed and tested a synthetic platform based on both uniaxial mechanical strain and buckling-induced elastomer microtopography. Bacterial biofilm attachment to the dynamic substrates was studied under an array of parameters, including strain amplitude and timescale (1–100 mm s −1 ), surface wrinkle length scale, bacterial species and cell geometry, and growth time. The optimal conditions for achieving up to ∼ 80% Pseudomonas aeruginosa biofilm reduction after 24 h growth and ∼ 60% reduction after 48 h were combinatorially elucidated to occur at 20% strain amplitude, a timescale of less than ∼ 5 min between strain cycles and a topography length scale corresponding to the cell dimension of ∼ 1 μm. Divergent effects on the attachment of P. aeruginosa, Staphylococcus aureus and Escherichia coli biofilms showed that the dynamic substrate also provides a new means of species-specific biofilm inhibition, or inversely, selection for a desired type of bacteria, without reliance on any toxic or transient surface chemical treatments. (paper)

  10. Biofilm attachment reduction on bioinspired, dynamic, micro-wrinkling surfaces

    Science.gov (United States)

    Epstein, Alexander K.; Hong, Donggyoon; Kim, Philseok; Aizenberg, Joanna

    2013-09-01

    Most bacteria live in multicellular communities known as biofilms that are adherent to surfaces in our environment, from sea beds to plumbing systems. Biofilms are often associated with clinical infections, nosocomial deaths and industrial damage such as bio-corrosion and clogging of pipes. As mature biofilms are extremely challenging to eradicate once formed, prevention is advantageous over treatment. However, conventional surface chemistry strategies are either generally transient, due to chemical masking, or toxic, as in the case of leaching marine antifouling paints. Inspired by the nonfouling skins of echinoderms and other marine organisms, which possess highly dynamic surface structures that mechanically frustrate bio-attachment, we have developed and tested a synthetic platform based on both uniaxial mechanical strain and buckling-induced elastomer microtopography. Bacterial biofilm attachment to the dynamic substrates was studied under an array of parameters, including strain amplitude and timescale (1-100 mm s-1), surface wrinkle length scale, bacterial species and cell geometry, and growth time. The optimal conditions for achieving up to ˜ 80% Pseudomonas aeruginosa biofilm reduction after 24 h growth and ˜ 60% reduction after 48 h were combinatorially elucidated to occur at 20% strain amplitude, a timescale of less than ˜ 5 min between strain cycles and a topography length scale corresponding to the cell dimension of ˜ 1 μm. Divergent effects on the attachment of P. aeruginosa, Staphylococcus aureus and Escherichia coli biofilms showed that the dynamic substrate also provides a new means of species-specific biofilm inhibition, or inversely, selection for a desired type of bacteria, without reliance on any toxic or transient surface chemical treatments.

  11. FLO11 expression and lipid biosynthesis are required for air-liquid biofilm formation in a Saccharomyces cerevisiae flor strain.

    Science.gov (United States)

    Zara, Giacomo; Goffrini, Paola; Lodi, Tiziana; Zara, Severino; Mannazzu, Ilaria; Budroni, Marilena

    2012-11-01

    Air-liquid biofilm formation is largely dependent on Flo11p and seems related to cell lipid content and composition. Here, it is shown that in the presence of cerulenin, a known inhibitor of the fatty acid synthase complex, biofilm formation is inhibited together with FLO11 transcription in a flor strain of Saccharomyces cerevisiae, while the administration of saturated fatty acids to cerulenin-containing medium restores biofilm formation and FLO11 transcription. It is also shown that, in biofilm cells, the FLO11 transcription is accompanied by the transcription of ACC1, ACS1 and INO1 key genes in lipid biosynthesis and that biofilm formation is affected by the lack of inositol in flor medium. These results are compatible with the hypothesis that the air-liquid biofilm formation depends on FLO11 transcription levels as well as on fatty acids biosynthesis. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  12. Biofilm architecture in a novel pressurized biofilm reactor.

    Science.gov (United States)

    Jiang, Wei; Xia, Siqing; Duan, Liang; Hermanowicz, Slawomir W

    2015-01-01

    A novel pure-oxygen pressurized biofilm reactor was operated at different organic loading, mechanical shear and hydrodynamic conditions to understand the relationships between biofilm architecture and its operation. The ultimate goal was to improve the performance of the biofilm reactor. The biofilm was labeled with seven stains and observed with confocal laser scanning microscopy. Unusual biofilm architecture of a ribbon embedded between two surfaces with very few points of attachment was observed. As organic loading increased, the biofilm morphology changed from a moderately rough layer into a locally smoother biomass with significant bulging protuberances, although the chemical oxygen demand (COD) removal efficiency remained unchanged at about 75%. At higher organic loadings, biofilms contained a larger fraction of active cells distributed uniformly within a proteinaceous matrix with decreasing polysaccharide content. Higher hydrodynamic shear in combination with high organic loading resulted in the collapse of biofilm structure and a substantial decrease in reactor performance (a COD removal of 16%). Moreover, the important role of proteins for the spatial distribution of active cells was demonstrated quantitatively.

  13. Marine biofilm bacteria evade eukaryotic predation by targeted chemical defense.

    Directory of Open Access Journals (Sweden)

    Carsten Matz

    Full Text Available Many plants and animals are defended from predation or herbivory by inhibitory secondary metabolites, which in the marine environment are very common among sessile organisms. Among bacteria, where there is the greatest metabolic potential, little is known about chemical defenses against bacterivorous consumers. An emerging hypothesis is that sessile bacterial communities organized as biofilms serve as bacterial refuge from predation. By testing growth and survival of two common bacterivorous nanoflagellates, we find evidence that chemically mediated resistance against protozoan predators is common among biofilm populations in a diverse set of marine bacteria. Using bioassay-guided chemical and genetic analysis, we identified one of the most effective antiprotozoal compounds as violacein, an alkaloid that we demonstrate is produced predominately within biofilm cells. Nanomolar concentrations of violacein inhibit protozoan feeding by inducing a conserved eukaryotic cell death program. Such biofilm-specific chemical defenses could contribute to the successful persistence of biofilm bacteria in various environments and provide the ecological and evolutionary context for a number of eukaryote-targeting bacterial metabolites.

  14. Xylella fastidiosa differentially accumulates mineral elements in biofilm and planktonic cells.

    Science.gov (United States)

    Cobine, Paul A; Cruz, Luisa F; Navarrete, Fernando; Duncan, Daniel; Tygart, Melissa; De La Fuente, Leonardo

    2013-01-01

    Xylella fastidiosa is a bacterial plant pathogen that infects numerous plant hosts. Disease develops when the bacterium colonizes the xylem vessels and forms a biofilm. Inductively coupled plasma optical emission spectroscopy was used to examine the mineral element content of this pathogen in biofilm and planktonic states. Significant accumulations of copper (30-fold), manganese (6-fold), zinc (5-fold), calcium (2-fold) and potassium (2-fold) in the biofilm compared to planktonic cells were observed. Other mineral elements such as sodium, magnesium and iron did not significantly differ between biofilm and planktonic cells. The distribution of mineral elements in the planktonic cells loosely mirrors the media composition; however the unique mineral element distribution in biofilm suggests specific mechanisms of accumulation from the media. A cell-to-surface attachment assay shows that addition of 50 to 100 µM Cu to standard X. fastidiosa media increases biofilm, while higher concentrations (>200 µM) slow cell growth and prevent biofilm formation. Moreover cell-to-surface attachment was blocked by specific chelation of copper. Growth of X. fastidiosa in microfluidic chambers under flow conditions showed that addition of 50 µM Cu to the media accelerated attachment and aggregation, while 400 µM prevented this process. Supplementation of standard media with Mn showed increased biofilm formation and cell-to-cell attachment. In contrast, while the biofilm accumulated Zn, supplementation to the media with this element caused inhibited growth of planktonic cells and impaired biofilm formation. Collectively these data suggest roles for these minerals in attachment and biofilm formation and therefore the virulence of this pathogen.

  15. Xylella fastidiosa differentially accumulates mineral elements in biofilm and planktonic cells.

    Directory of Open Access Journals (Sweden)

    Paul A Cobine

    Full Text Available Xylella fastidiosa is a bacterial plant pathogen that infects numerous plant hosts. Disease develops when the bacterium colonizes the xylem vessels and forms a biofilm. Inductively coupled plasma optical emission spectroscopy was used to examine the mineral element content of this pathogen in biofilm and planktonic states. Significant accumulations of copper (30-fold, manganese (6-fold, zinc (5-fold, calcium (2-fold and potassium (2-fold in the biofilm compared to planktonic cells were observed. Other mineral elements such as sodium, magnesium and iron did not significantly differ between biofilm and planktonic cells. The distribution of mineral elements in the planktonic cells loosely mirrors the media composition; however the unique mineral element distribution in biofilm suggests specific mechanisms of accumulation from the media. A cell-to-surface attachment assay shows that addition of 50 to 100 µM Cu to standard X. fastidiosa media increases biofilm, while higher concentrations (>200 µM slow cell growth and prevent biofilm formation. Moreover cell-to-surface attachment was blocked by specific chelation of copper. Growth of X. fastidiosa in microfluidic chambers under flow conditions showed that addition of 50 µM Cu to the media accelerated attachment and aggregation, while 400 µM prevented this process. Supplementation of standard media with Mn showed increased biofilm formation and cell-to-cell attachment. In contrast, while the biofilm accumulated Zn, supplementation to the media with this element caused inhibited growth of planktonic cells and impaired biofilm formation. Collectively these data suggest roles for these minerals in attachment and biofilm formation and therefore the virulence of this pathogen.

  16. Acid environments affect biofilm formation and gene expression in isolates of Salmonella enterica Typhimurium DT104.

    Science.gov (United States)

    O'Leary, Denis; McCabe, Evonne M; McCusker, Matthew P; Martins, Marta; Fanning, Séamus; Duffy, Geraldine

    2015-08-03

    The aim of this study was to examine the survival and potential virulence of biofilm-forming Salmonella Typhimurium DT104 under mild acid conditions. Salmonella Typhimurium DT104 employs an acid tolerance response (ATR) allowing it to adapt to acidic environments. The threat that these acid adapted cells pose to food safety could be enhanced if they also produce biofilms in acidic conditions. The cells were acid-adapted by culturing them in 1% glucose and their ability to form biofilms on stainless steel and on the surface of Luria Bertani (LB) broth at pH7 and pH5 was examined. Plate counts were performed to examine cell survival. RNA was isolated from cells to examine changes in the expression of genes associated with virulence, invasion, biofilm formation and global gene regulation in response to acid stress. Of the 4 isolates that were examined only one (1481) that produced a rigid biofilm in LB broth at pH7 also formed this same structure at pH5. This indicated that the lactic acid severely impeded the biofilm producing capabilities of the other isolates examined under these conditions. Isolate 1481 also had higher expression of genes associated with virulence (hilA) and invasion (invA) with a 24.34-fold and 13.68-fold increase in relative gene expression respectively at pH5 compared to pH7. Although genes associated with biofilm formation had increased expression in response to acid stress for all the isolates this only resulted in the formation of a biofilm by isolate 1481. This suggests that in addition to the range of genes associated with biofilm production at neutral pH, there are genes whose protein products specifically aid in biofilm production in acidic environments. Furthermore, it highlights the potential for the use of lactic acid for the inhibition of Salmonella biofilms. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Novel microfluidic system for online monitoring of biofilm dynamics by electrical impedance spectroscopy and amperometry

    Science.gov (United States)

    Bruchmann, Julia; Sachsenheimer, Kai; Schwartz, Thomas; Rapp, Bastian E.

    2016-03-01

    Biofilm formation is ubiquitous in nature where microorganisms attach to surfaces and form highly adapted and protected communities. In technical and industrial systems like drinking water supply, food production or shipping industry biofilms are a major cause of product contamination, biofouling, and biocorrosion. Therefore, understanding of biofilm formation and means of preventing biofilm formation is important to develop novel biofilm treatment strategies. A system allowing directly online detection and monitoring biofilm formation is necessary. However, until today, there are little to none technical systems featuring a non-destructive real-time characterization of biofilm formation in a highthroughput manner. This paper presents such a microfluidic system based on electrical impedance spectroscopy (EIS) and amperomertic current measurement. The sensor consists of four modules, each housing 24 independent electrodes within 12 microfluidic channels. Attached biomass on the electrodes is monitored as increased inhibition in charge transfer by EIS and a change in metabolic activity is measured as change in produced electric current by amperometry. This modular sensor system is highly adaptable and suitable for a broad range of microbiological applications. Among others, biofilm formation processes can be characterized online, biofilm manipulation like inactivation or destabilization can be monitored in real-time and gene expression can be analyzed in parallel. The use of different electrode designs allows effective biofilm studies during all biofilm phases. The whole system was recently extended by an integrated pneumatic microfluidic pump which enables easy handling procedures. Further developments of this pumping module will allow a fully- automated computer-controlled valving and pumping.

  18. Relative contributions of norspermidine synthesis and signaling pathways to the regulation of Vibrio cholerae biofilm formation.

    Directory of Open Access Journals (Sweden)

    Caitlin K Wotanis

    Full Text Available The polyamine norspermidine is one of the major polyamines synthesized by Vibrionales and has also been found in various aquatic organisms. Norspermidine is among the environmental signals that positively regulate Vibrio cholerae biofilm formation. The NspS/MbaA signaling complex detects extracellular norspermidine and mediates the response to this polyamine. Norspermidine binding to the NspS periplasmic binding protein is thought to inhibit the phosphodiesterase activity of MbaA, increasing levels of the biofilm-promoting second messenger cyclic diguanylate monophosphate, thus enhancing biofilm formation. V. cholerae can also synthesize norspermidine using the enzyme NspC as well as import it from the environment. Deletion of the nspC gene was shown to reduce accumulation of bacteria in biofilms, leading to the conclusion that intracellular norspermidine is also a positive regulator of biofilm formation. Because V. cholerae uses norspermidine to synthesize the siderophore vibriobactin it is possible that intracellular norspermidine is required to obtain sufficient amounts of iron, which is also necessary for robust biofilm formation. The objective of this study was to assess the relative contributions of intracellular and extracellular norspermidine to the regulation of biofilm formation in V. cholerae. We show the biofilm defect of norspermidine synthesis mutants does not result from an inability to produce vibriobactin as vibriobactin synthesis mutants do not have diminished biofilm forming abilities. Furthermore, our work shows that extracellular, but not intracellular norspermidine, is mainly responsible for promoting biofilm formation. We establish that the NspS/MbaA signaling complex is the dominant mediator of biofilm formation in response to extracellular norspermidine, rather than norspermidine synthesized by NspC or imported into the cell.

  19. Staphylococcus aureus biofilms: recent developments in biofilm dispersal.

    Science.gov (United States)

    Lister, Jessica L; Horswill, Alexander R

    2014-01-01

    Staphylococcus aureus is a major cause of nosocomial and community-acquired infections and represents a significant burden on the healthcare system. S. aureus attachment to medical implants and host tissue, and the establishment of a mature biofilm, play an important role in the persistence of chronic infections. The formation of a biofilm, and encasement of cells in a polymer-based matrix, decreases the susceptibility to antimicrobials and immune defenses, making these infections difficult to eradicate. During infection, dispersal of cells from the biofilm can result in spread to secondary sites and worsening of the infection. In this review, we discuss the current understanding of the pathways behind biofilm dispersal in S. aureus, with a focus on enzymatic and newly described broad-spectrum dispersal mechanisms. Additionally, we explore potential applications of dispersal in the treatment of biofilm-mediated infections.

  20. Effects of Aronia melanocarpa Constituents on Biofilm Formation of Escherichia coli and Bacillus cereus

    Directory of Open Access Journals (Sweden)

    Marie Bräunlich

    2013-12-01

    Full Text Available Many bacteria growing on surfaces form biofilms. Adaptive and genetic changes of the microorganisms in this structure make them resistant to antimicrobial agents. Biofilm-forming organisms on medical devices can pose serious threats to human health. Thus, there is a need for novel prevention and treatment strategies. This study aimed to evaluate the ability of Aronia melanocarpa extracts, subfractions and compounds to prevent biofilm formation and to inhibit bacterial growth of Escherichia coli and Bacillus cereus in vitro. It was found that several aronia substances possessed anti-biofilm activity, however, they were not toxic to the species screened. This non-toxic inhibition may confer a lower potential for resistance development compared to conventional antimicrobials.

  1. Effect of alcohols on filamentation, growth, viability and biofilm development in Candida albicans.

    Science.gov (United States)

    Chauhan, Nitin M; Shinde, Ravikumar B; Karuppayil, S Mohan

    2013-12-01

    In this study we report the potential of alcohols as morphogenetic regulators in Candida albicans. All the alcohols tested influenced various modes of growth like planktonic as well as biofilm forms. Viability was affected at high concentrations. Among the alcohols, the response of C. albicans to amyl alcohol (pentanol) was noteworthy. Amyl alcohol at a concentration 0.5% which was not inhibitory to growth and viability specifically inhibited morphogenetic switching from yeast to hyphal forms. It also inhibited normal biofilm development favoring yeast dominated biofilms. Based on this study we hypothesize that alcohols produced under anaerobic conditions may not favor biofilm development and support dissemination of yeast cells. Since anaerobic conditions are not found to favor production of quorum sensing molecules like farnesol, the alcohols may play a role in morphogenetic regulation.

  2. Study of biofilm influenced corrosion on cast iron pipes in reclaimed water

    International Nuclear Information System (INIS)

    Zhang, Haiya; Tian, Yimei; Wan, Jianmei; Zhao, Peng

    2015-01-01

    Highlights: • Compared to sterile water, biofilm in reclaimed water promoted corrosion process significantly. • Corrosion rate was accelerated by the biofilm in the first 7 days but was inhibited afterwards. • There was an inverse correlation between the biofilm thickness and general corrosion rate. • Corrosion process was influenced by bacteria, EPS and corrosion products comprehensively. • The corrosion process can be divided into three different stages in our study. - Abstract: Biofilm influenced corrosion on cast iron pipes in reclaimed water was systemically studied using the weight loss method and electrochemical impedance spectroscopy (EIS). The results demonstrated that compared to sterile water, the existence of the biofilm in reclaimed water promoted the corrosion process significantly. The characteristics of biofilm on cast iron coupons were examined by the surface profiler, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The bacterial counts in the biofilm were determined using the standard plate count method and the most probable number (MPN). The results demonstrated that the corrosion process was influenced by the settled bacteria, EPS, and corrosion products in the biofilm comprehensively. But, the corrosion mechanisms were different with respect to time and could be divided into three stages in our study. Furthermore, several corresponding corrosion mechanisms were proposed for different immersion times.

  3. Study of biofilm influenced corrosion on cast iron pipes in reclaimed water

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Haiya, E-mail: flying850612@126.com; Tian, Yimei, E-mail: ymtian_2000@126.com; Wan, Jianmei, E-mail: 563926510@qq.com; Zhao, Peng, E-mail: zhpeng@tju.edu.cn

    2015-12-01

    Highlights: • Compared to sterile water, biofilm in reclaimed water promoted corrosion process significantly. • Corrosion rate was accelerated by the biofilm in the first 7 days but was inhibited afterwards. • There was an inverse correlation between the biofilm thickness and general corrosion rate. • Corrosion process was influenced by bacteria, EPS and corrosion products comprehensively. • The corrosion process can be divided into three different stages in our study. - Abstract: Biofilm influenced corrosion on cast iron pipes in reclaimed water was systemically studied using the weight loss method and electrochemical impedance spectroscopy (EIS). The results demonstrated that compared to sterile water, the existence of the biofilm in reclaimed water promoted the corrosion process significantly. The characteristics of biofilm on cast iron coupons were examined by the surface profiler, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The bacterial counts in the biofilm were determined using the standard plate count method and the most probable number (MPN). The results demonstrated that the corrosion process was influenced by the settled bacteria, EPS, and corrosion products in the biofilm comprehensively. But, the corrosion mechanisms were different with respect to time and could be divided into three stages in our study. Furthermore, several corresponding corrosion mechanisms were proposed for different immersion times.

  4. Antifungal and Anti-Biofilm Activities of Acetone Lichen Extracts against Candida albicans

    Directory of Open Access Journals (Sweden)

    Marion Millot

    2017-04-01

    Full Text Available Candida albicans is a commensal coloniser of the human gastrointestinal tract and an opportunistic pathogen, especially thanks to its capacity to form biofilms. This lifestyle is frequently involved in infections and increases the yeast resistance to antimicrobials and immune defenses. In this context, 38 lichen acetone extracts have been prepared and evaluated for their activity against C. albicans planktonic and sessile cells. Minimum inhibitory concentrations of extracts (MICs were determined using the broth microdilution method. Anti-biofilm activity was evaluated using tetrazolium salt (XTT assay as the ability to inhibit the maturation phase (anti-maturation or to eradicate a preformed 24 h old biofilm (anti-biofilm. While none of the extracts were active against planktonic cells, biofilm maturation was limited by 11 of the tested extracts. Seven extracts displayed both anti-maturation and anti-biofilm activities (half maximal inhibitory concentrations IC50_mat and IC50_biof ≤ 100 µg/mL; Evernia prunastri and Ramalina fastigiata were the most promising lichens (IC50_mat < 4 µg/mL and IC50_biof < 10 µg/mL. Chemical profiles of the active extracts performed by thin layer chromatography (TLC and high performance liquid chromatography (HPLC have been analyzed. Depsides, which were present in large amounts in the most active extracts, could be involved in anti-biofilm activities. This work confirmed that lichens represent a reservoir of compounds with anti-biofilm potential.

  5. Impaired respiration elicits SrrAB-dependent programmed cell lysis and biofilm formation in Staphylococcus aureus

    Science.gov (United States)

    Mashruwala, Ameya A; van de Guchte, Adriana; Boyd, Jeffrey M

    2017-01-01

    Biofilms are communities of microorganisms attached to a surface or each other. Biofilm-associated cells are the etiologic agents of recurrent Staphylococcus aureus infections. Infected human tissues are hypoxic or anoxic. S. aureus increases biofilm formation in response to hypoxia, but how this occurs is unknown. In the current study we report that oxygen influences biofilm formation in its capacity as a terminal electron acceptor for cellular respiration. Genetic, physiological, or chemical inhibition of respiratory processes elicited increased biofilm formation. Impaired respiration led to increased cell lysis via divergent regulation of two processes: increased expression of the AtlA murein hydrolase and decreased expression of wall-teichoic acids. The AltA-dependent release of cytosolic DNA contributed to increased biofilm formation. Further, cell lysis and biofilm formation were governed by the SrrAB two-component regulatory system. Data presented support a model wherein SrrAB-dependent biofilm formation occurs in response to the accumulation of reduced menaquinone. DOI: http://dx.doi.org/10.7554/eLife.23845.001 PMID:28221135

  6. Biofilm removal technique using sands as a research tool for accessing microbial attachment on surface

    Directory of Open Access Journals (Sweden)

    Nathanon Trachoo

    2004-01-01

    Full Text Available Biofilms have profound impacts on improved survival of the constituent microorganisms in nature. Biofilms were believed to protect constituent microorganisms from sanitizer treatment, provide a more suitable habitat for microorganisms, and become a site for genetic material exchanges between microorganisms. As we realize more about the significance of biofilm, methods used for biofilm study should be consistently developed and evaluated. To determine microbial attachment on surfaces, usually biofilms are grown on substratum surfaces and removed by vortexing with glass beads or scraping. However, scraping is not as effective as vortexing with glass beads. Another approach is direct-agar overlaying which cannot be used with high density biofilm. In this experiment, we compared effectiveness of glass beads (298±28 μm in diameter and sands (width: 221±55 μm and length: 329±118 μm in removing biofilm of Pseudomonas aeruginosa by vortexing method. The results suggested that acid-washed sands, which are significantly less inexpensive than glass beads, were as effective as (P>0.05 analytical grade glass beads in Pseudomonas aeruginosa biofilm removal without inhibiting growth of the organism.

  7. Antibacterial Effect of Dental Adhesive Containing Dimethylaminododecyl Methacrylate on the Development of Streptococcus mutans Biofilm

    Directory of Open Access Journals (Sweden)

    Suping Wang

    2014-07-01

    Full Text Available Antibacterial bonding agents and composites containing dimethylaminododecyl methacrylate (DMADDM have been recently developed. The objectives of this study were to investigate the antibacterial effect of novel adhesives containing different mass fractions of DMADDM on Streptococcus mutans (S. mutans biofilm at different developmental stages. Different mass fractions of DMADDM were incorporated into adhesives and S. mutans biofilm at different developmetal stages were analyzed by MTT assays, lactic acid measurement, confocal laser scanning microscopy and scanning electron microscopy observations. Exopolysaccharides (EPS staining was used to analyze the inhibitory effect of DMADDM on the biofilm extracellular matrix. Dentin microtensile strengths were also measured. Cured adhesives containing DMADDM could greatly reduce metabolic activity and lactic acid production during the development of S. mutans biofilms (p < 0.05. In earlier stages of biofilm development, there were no significant differences of inhibitory effects between the 2.5% DMADDM and 5% DMADDM group. However, after 72 h, the anti-biofilm effects of adhesives containing 5% DMADDM were significantly stronger than any other group. Incorporation of DMADDM into adhesive did not adversely affect dentin bond strength. In conclusion, adhesives containing DMADDM inhibited the growth, lactic acid production and EPS metabolism of S. mutans biofilm at different stages, with no adverse effect on its dentin adhesive bond strength. The bonding agents have the potential to control dental biofilms and combat tooth decay, and DMADDM is promising for use in a wide range of dental adhesive systems and restoratives.

  8. In Situ Molecular Imaging of the Biofilm and Its Matrix

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Yuanzhao; Zhou, Yufan; Yao, Juan; Szymanski, Craig J.; Fredrickson, Jim K.; Shi, Liang; Cao, B.; Zhu, Zihua; Yu, Xiao-Ying

    2016-11-15

    Molecular mapping of live biofilms at submicron resolution presents a grand challenge. Here, we present the first chemical mapping results of biofilm extracellular polymeric sub-stance (EPS) components in biofilms using correlative imaging be-tween super resolution florescence microscopy and liquid time-of-flight secondary ion mass spectrometry (ToF-SIMS). Shewanella oneidensis is used as a model organism. Heavy metal anions chro-mate (Cr2O72-) consisting of chromium Cr (VI) was a model envi-ronmental stressor used to treat the biofilms. Of particular interest, biologically relevant water clusters have been first observed in the biofilms. Characteristic fragments of biofilm matrix components such as proteins, polysaccharides, and lipids can be spatially im-aged. Furthermore, characteristic fatty acids (e.g., palmitic acid), quinolone signal, and riboflavin fragments are found to respond af-ter the biofilm is treated with Cr (VI), leading to biofilm dispersion. Significant changes in water clusters and quorum sensing signals indicative of intercellular communication in the aqueous environ-ment are observed, suggesting that they might result in fatty acid synthesis and inhibit riboflavin production. The Cr (VI) reduction seems to follow the Mtr pathway leading to Cr (III) formation. Our approach potentially opens a new avenue for mechanistic insight of microbial community processes and communications using in situ imaging mass spectrometry and superresolution optical micros-copy.

  9. Inhibitory effects of Lactobacillus rhamnosus and Lactobacillus casei on Candida biofilm of denture surface.

    Science.gov (United States)

    Song, Young-Gyun; Lee, Sung-Hoon

    2017-04-01

    Candida albicans biofilm is associated with denture-related stomatitis and oral candidiasis of elderly. Probiotics are beneficial bacteria and have antibacterial activity against pathogenic bacteria. The purpose of this study was to investigate the antifungal activity of various probiotics against C. albicans and the inhibitory effects of probiotics on Candida biofilm on the denture surface. The spent culture media of various probiotics were investigated the antifungal efficacy against C. albicans. Candida biofilm was formed on a denture base resin and was then treated with Lactobacillus rhamnosus and Lactobacillus casei. Also, the biofilms of L. rhamnosus and L. casei were formed and were sequentially treated with C. albicans. Colony-forming units of C. albicans on the denture surface were counted after spreading on agar plate. The denture base resin was treated with the spent culture media for 30days, after which the denture surface roughness was analyzed with an atomic force microscope. L. rhamnosus and L. casei exhibited stronger antifungal activity than other probiotics. The spent culture medium of L. rhamnosus and L. casei exhibited the antifungal activity against blastoconidia and biofilm of C. albicans. L. rhamnosus and L. casei showed the antifungal activity against Candida biofilm, and the biofilm of L. rhamnosus and L. casei inhibited formation of Candida biofilm on denture surface. Neither of the probiotics affected the surface roughness of the denture base resin. L. rhamnosus and L. casei may be the ideal probiotics for the prevention and treatment of denture-related stomatitis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Modeling sediment transport with an integrated view of the biofilm effects

    Science.gov (United States)

    Fang, H. W.; Lai, H. J.; Cheng, W.; Huang, L.; He, G. J.

    2017-09-01

    Most natural sediment is invariably covered by biofilms in reservoirs and lakes, which have significant influence on bed form dynamics and sediment transport, and also play a crucial role in natural river evolution, pollutant transport, and habitat changes. However, most models for sediment transport are based on experiments using clean sediments without biological materials. In this study, a three-dimensional mathematical model of hydrodynamics and sediment transport is presented with a comprehensive consideration of the biofilm effects. The changes of the bed resistance mainly due to the different bed form dynamics of the biofilm-coated sediment (biosediment), which affect the hydrodynamic characteristics, are considered. Moreover, the variations of parameters related to sediment transport after the biofilm growth are integrated, including the significant changes of the incipient velocity, settling velocity, reference concentration, and equilibrium bed load transport rate. The proposed model is applied to evaluate the effects of biofilms on the hydrodynamic characteristics and sediment transport in laboratory experiments. Results indicate that the mean velocity increases after the biofilm growth, and the turbulence intensity near the river bed decreases under the same flow condition. Meanwhile, biofilm inhibits sediment from moving independently. Thus, the moderate erosion is observed for biosediment resulting in smaller suspended sediment concentrations. The proposed model can reasonably reflect these sediment transport characteristics with biofilms, and the approach to integration of the biological impact could also be used in other modeling of sediment transport, which can be further applied to provide references for the integrated management of natural aqueous systems.

  11. Metabolomics-Based Screening of Biofilm-Inhibitory Compounds against Pseudomonas aeruginosa from Burdock Leaf

    Directory of Open Access Journals (Sweden)

    Zaixiang Lou

    2015-09-01

    Full Text Available Screening of anti-biofilm compounds from the burdock leaf based on metabolomics is reported here. The crystal violet assay indicated 34% ethanol elution fraction of burdock leaf could completely inhibit biofilm formation of Pseudomonas aeruginosa at 1 mg·mL−1. Then, the chemical composition of burdock leaf fraction was analyzed by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS and 11 active compounds (chlorogenic acid, caffeic acid, p-coumaric acid, quercetin, ursolic acid, rutin, cynarin, luteolin, crocin, benzoic acid, and Tenacissoside I were identified. Lastly, UPLC-MS analysis was employed to obtain the metabolic fingerprints of burdock leaf fractions before and after inhibiting the biofilm of Pseudomonas aeruginosa. The metabolic fingerprints were transformed to data, analyzed with PLS-DA (partial least squares discriminant analysis and the peaks whose area was significantly changed were found out. Thus, 81 compounds were screened as potential anti-biofilm ingredients. Among them, rutin, ursolic acid, caffeic acid, p-coumaric acid and quercetin were identified and confirmed as the main anti-biofilm compounds in burdock leaf. The study provided basic anti-biofilm profile data for the compounds in burdock leaf, as well as provided a convenient method for fast screening of anti-biofilm compounds from natural plants.

  12. Antibacterial activity of food-grade chitosan against Vibrio parahaemolyticus biofilms.

    Science.gov (United States)

    Xie, Ting; Liao, Zhenlin; Lei, Huan; Fang, Xiang; Wang, Jie; Zhong, Qingping

    2017-09-01

    Biofilm is a community composed of microbes and the extracellular polymeric substances. This special architecture poses a significant public health risk as it increases the fitness of bacteria in harsh conditions and renders bacterial resistance to antimicrobial agents and cleaning. In this study, we investigated the inhibition and eradication effects of chitosan on the biofilm of Vibrio parahaemolyticus, an important food-borne pathogen. The crystal violet staining, [2, 3-bis (2-methoxy-4-nitro-5- sulfophenyl)-2H-tetrazolium-5-carboxanilide] (XTT) reduction method, phenol-sulfuric acid method, fluorescence microscope and confocal laser scanning microscope (CLSM) observation were conducted. The results indicated that the minimum inhibitory concentration (MIC) of chitosan was 1.25 mg/mL. Sub-MIC of chitosan could significantly inhibit biofilm formation, reduce the metabolic activities and the secretion of extracellular polysaccharide (EPS). Moreover, chitosan at 4MIC could eradicate 85.06% mature biofilm of V. parahaemolyticus, and decrease 81.43% EPS in mature biofilm. These results were also confirmed by the visual images obtained from fluorescence microscopy and CLSM. This study elucidated that chitosan was not only effective to prevent biofilm formation, but also eradicate mature biofilms of V. parahaemolyticus. Copyright © 2017. Published by Elsevier Ltd.

  13. The Effect of a Silver Nanoparticle Polysaccharide System on Streptococcal and Saliva-Derived Biofilms

    Directory of Open Access Journals (Sweden)

    Luigina Cellini

    2013-06-01

    Full Text Available In this work, we studied the antimicrobial properties of a nanocomposite system based on a lactose-substituted chitosan and silver nanoparticles: Chitlac-nAg. Twofold serial dilutions of the colloidal Chitlac-nAg solution were both tested on Streptococcus mitis, Streptococcus mutans, and Streptococcus oralis planktonic phase and biofilm growth mode as well as on saliva samples. The minimum inhibitory and bactericidal concentrations of Chitlac-nAg were evaluated together with its effect on sessile cell viability, as well as both on biofilm formation and on preformed biofilm. In respect to the planktonic bacteria, Chitlac-nAg showed an inhibitory/bactericidal effect against all streptococcal strains at 0.1% (v/v, except for S. mitis ATCC 6249 that was inhibited at one step less. On preformed biofilm, Chitlac-nAg at a value of 0.2%, was able to inhibit the bacterial growth on the supernatant phase as well as on the mature biofilm. For S. mitis ATCC 6249, the biofilm inhibitory concentration of Chitlac-nAg was 0.1%. At sub-inhibitory concentrations, the Streptococcal strains adhesion capability on a polystyrene surface showed a general reduction following a concentration-dependent-way; a similar effect was obtained for the metabolic biofilm activity. From these results, Chitlac-nAg seems to be a promising antibacterial and antibiofilm agent able to hinder plaque formation.

  14. Silver nanoparticles impede the biofilm formation by Pseudomonas aeruginosa and Staphylococcus epidermidis.

    Science.gov (United States)

    Kalishwaralal, Kalimuthu; BarathManiKanth, Selvaraj; Pandian, Sureshbabu Ram Kumar; Deepak, Venkataraman; Gurunathan, Sangiliyandi

    2010-09-01

    Biofilms are ensued due to bacteria that attach to surfaces and aggregate in a hydrated polymeric matrix. Formation of these sessile communities and their inherent resistance to anti-microbial agents are the source of many relentless and chronic bacterial infections. Such biofilms are responsible play a major role in development of ocular related infectious diseases in human namely microbial keratitis. Different approaches have been used for preventing biofilm related infections in health care settings. Many of these methods have their own demerits that include chemical based complications; emergent antibiotic resistant strains, etc. silver nanoparticles are renowned for their influential anti-microbial activity. Hence the present study over the biologically synthesized silver nanoparticles, exhibited a potential anti-biofilm activity that was tested in vitro on biofilms formed by Pseudomonas aeruginosa and Staphylococcus epidermidis during 24-h treatment. Treating these organisms with silver nanoparticles resulted in more than 95% inhibition in biofilm formation. The inhibition was known to be invariable of the species tested. As a result this study demonstrates the futuristic application of silver nanoparticles in treating microbial keratitis based on its potential anti-biofilm activity. Copyright 2010 Elsevier B.V. All rights reserved.

  15. Antibiotic treatment of biofilm infections

    DEFF Research Database (Denmark)

    Ciofu, Oana; Rojo-Molinero, Estrella; Macià, María D.

    2017-01-01

    Bacterial biofilms are associated with a wide range of infections, from those related to exogenous devices, such as catheters or prosthetic joints, to chronic tissue infections such as those occurring in the lungs of cystic fibrosis patients. Biofilms are recalcitrant to antibiotic treatment due ...

  16. Experimental evolution in biofilm populations

    Science.gov (United States)

    Steenackers, Hans P.; Parijs, Ilse; Foster, Kevin R.; Vanderleyden, Jozef

    2016-01-01

    Biofilms are a major form of microbial life in which cells form dense surface associated communities that can persist for many generations. The long-life of biofilm communities means that they can be strongly shaped by evolutionary processes. Here, we review the experimental study of evolution in biofilm communities. We first provide an overview of the different experimental models used to study biofilm evolution and their associated advantages and disadvantages. We then illustrate the vast amount of diversification observed during biofilm evolution, and we discuss (i) potential ecological and evolutionary processes behind the observed diversification, (ii) recent insights into the genetics of adaptive diversification, (iii) the striking degree of parallelism between evolution experiments and real-life biofilms and (iv) potential consequences of diversification. In the second part, we discuss the insights provided by evolution experiments in how biofilm growth and structure can promote cooperative phenotypes. Overall, our analysis points to an important role of biofilm diversification and cooperation in bacterial survival and productivity. Deeper understanding of both processes is of key importance to design improved antimicrobial strategies and diagnostic techniques. PMID:26895713

  17. Microalgal biofilms for wastewater treatment

    NARCIS (Netherlands)

    Boelee, N.C.

    2013-01-01

    The objective of this thesis was to explore the possibilities of using microalgal biofilms for the treatment of municipal wastewater, with a focus on the post-treatment of municipal wastewater effluent. The potential of microalgal biofilms for wastewater treatment was first investigated using a

  18. Microbial ecology of phototrophic biofilms

    NARCIS (Netherlands)

    Roeselers, G.

    2007-01-01

    Biofilms are layered structures of microbial cells and an extracellular matrix of polymeric substances, associated with surfaces and interfaces. Biofilms trap nutrients for growth of the enclosed microbial community and help prevent detachment of cells from surfaces in flowing systems. Phototrophic

  19. Bacterial Biofilms in Jones Tubes.

    Science.gov (United States)

    Ahn, Eric S; Hauck, Matthew J; Kirk Harris, Jonathan; Robertson, Charles E; Dailey, Roger A

    To investigate the presence and microbiology of bacterial biofilms on Jones tubes (JTs) by direct visualization with scanning electron microscopy and polymerase chain reaction (PCR) of representative JTs, and to correlate these findings with inflammation and/or infection related to the JT. In this study, prospective case series were performed. JTs were recovered from consecutive patients presenting to clinic for routine cleaning or recurrent irritation/infection. Four tubes were processed for scanning electron microscopy alone to visualize evidence of biofilms. Two tubes underwent PCR alone for bacterial quantification. One tube was divided in half and sent for scanning electron microscopy and PCR. Symptoms related to the JTs were recorded at the time of recovery. Seven tubes were obtained. Five underwent SEM, and 3 out of 5 showed evidence of biofilms (60%). Two of the 3 biofilms demonstrated cocci and the third revealed rods. Three tubes underwent PCR. The predominant bacteria identified were Pseudomonadales (39%), Pseudomonas (16%), and Staphylococcus (14%). Three of the 7 patients (43%) reported irritation and discharge at presentation. Two symptomatic patients, whose tubes were imaged only, revealed biofilms. The third symptomatic patient's tube underwent PCR only, showing predominantly Staphylococcus (56%) and Haemophilus (36%) species. Two of the 4 asymptomatic patients also showed biofilms. All symptomatic patients improved rapidly after tube exchange and steroid antibiotic drops. Bacterial biofilms were variably present on JTs, and did not always correlate with patients' symptoms. Nevertheless, routine JT cleaning is recommended to treat and possibly prevent inflammation caused by biofilms.

  20. Interaction of Nanoparticles with Biofilms

    Science.gov (United States)

    In this work we have studied the interaction and adsorption of engineered nanoparticles such as TiO2, ZnO, CeO2 , and carbon nanotubes with biofilms. Biofilm is an extracellular polymeric substance coating comprised of living material and it is an aggregation of bacteria, algae, ...

  1. The Effects of Allium sativum Extracts on Biofilm Formation and Activities of Six Pathogenic Bacteria.

    Science.gov (United States)

    Mohsenipour, Zeinab; Hassanshahian, Mehdi

    2015-08-01

    Garlic is considered a rich source of many compounds, which shows antimicrobial effects. The ability of microorganisms to adhere to both biotic and abiotic surfaces and to form biofilm is responsible for a number of diseases of chronic nature, demonstrating extremely high resistance to antibiotics. Bacterial biofilms are complex communities of sessile microorganisms, embedded in an extracellular matrix and irreversibly attached to various surfaces. The present study evaluated the antimicrobial activity of Allium sativum extract against the biofilms of six pathogenic bacteria and their free-living forms. The clinical isolates in this study had not been studied in any other studies, especially in regard to biofilm disruption and inhibition of biofilm cell metabolic activity. Antimicrobial activities of A. sativum L. extracts (methanol and ethanol extracts) against planktonic forms of bacteria were determined using the disc diffusion method. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) values were evaluated by a macrobroth dilution technique. The anti-biofilm effects were assessed by microtiter plate method. The results showed that the A. sativum L. extract discs did not have any zone of inhibition for the tested bacteria. However, The MIC values of A. sativum L. extracts (0.078 - 2.5 mg/mL) confirmed the high ability of these extracts for inhibition of planktonic bacteria. A. sativum L. extracts were efficient to inhibit biofilm structures and the concentration of each extract had a direct relation with the inhibitory effect. Finally, it can be suggested that the extracts of this plant be applied as antimicrobial agents against these pathogens, particularly in biofilm forms.

  2. Formation of 4-hydroxy-2,5-dimethyl-3[2H]-furanone by Zygosaccharomyces rouxii: identification of an intermediate.

    Science.gov (United States)

    Hauck, Tobias; Brühlmann, Fredi; Schwab, Wilfried

    2003-07-01

    The formation of the important flavor compound 4-hydroxy-2,5-dimethyl-3[2H]-furanone (HDMF; Furaneol) from D-fructose-1,6-bisphosphate by the yeast Zygosaccharomyces rouxii was studied with regard to the identification of intermediates present in the culture medium. Addition of o-phenylenediamine, a trapping reagent for alpha-dicarbonyls, to the culture medium and subsequent analysis by high-pressure liquid chromatography with diode array detection revealed the formation of three quinoxaline derivatives derived from D-fructose-1,6-bisphosphate under the applied growth conditions (30 degrees C; pH 4 to 5). Isolation and characterization of these compounds by tandem mass spectrometry and nuclear magnetic resonance spectroscopy led to the identification of phosphoric acid mono-(2,3,4-trihydroxy-4-quinoxaline-2-yl-butyl) ester (Q1), phosphoric acid mono-[2,3-dihydroxy-3-(3-methyl-quinoxaline-2-yl)-propyl] ester (Q2), and phosphoric acid mono-[2-hydroxy-3-(3-methyl-quinoxaline-2-yl)-propyl] ester (Q3). Q1 and Q2 were formed independently of Z. rouxii cells, whereas Q3 was detected only in incubation systems containing the yeast. Identification of Q2 demonstrated for the first time the chemical formation of 1-deoxy-2,3-hexodiulose-6-phosphate in the culture medium, a generally expected but never identified intermediate in the formation pathway of HDMF. Since HDMF was detected only in the presence of Z. rouxii cells, additional enzymatic steps were presumed. Incubation of periplasmic and cytosolic protein extracts obtained from yeast cells with D-fructose-1,6-bisphosphate led to the formation of HDMF, implying the presence of the required enzymes in both extracts.

  3. Interfacial Electrochemical Electron Transfer Processes in Bacterial Biofilm Environments on Au(111)

    DEFF Research Database (Denmark)

    Hu, Yifan; Zhang, Jingdong; Ulstrup, Jens

    2010-01-01

    We have studied Streptococcus mutans (S. mutans) biolilm growth and growth inhibition on Au(111)-surfaces using atomic force microscopy (AFM) and interfacial electrochemistry of a number of redox probe molecules. AFM of the biofilm growth and growth inhibition on both mica and Au(111)-surfaces wa...

  4. Biofilm models of polymicrobial infection.

    Science.gov (United States)

    Gabrilska, Rebecca A; Rumbaugh, Kendra P

    2015-01-01

    Interactions between microbes are complex and play an important role in the pathogenesis of infections. These interactions can range from fierce competition for nutrients and niches to highly evolved cooperative mechanisms between different species that support their mutual growth. An increasing appreciation for these interactions, and desire to uncover the mechanisms that govern them, has resulted in a shift from monomicrobial to polymicrobial biofilm studies in different disease models. Here we provide an overview of biofilm models used to study select polymicrobial infections and highlight the impact that the interactions between microbes within these biofilms have on disease progression. Notable recent advances in the development of polymicrobial biofilm-associated infection models and challenges facing the study of polymicrobial biofilms are addressed.

  5. Antibiotic resistance of bacterial biofilms

    DEFF Research Database (Denmark)

    Hoiby, N.; Bjarnsholt, T.; Givskov, M.

    2010-01-01

    A biofilm is a structured consortium of bacteria embedded in a self-produced polymer matrix consisting of polysaccharide, protein and DNA. Bacterial biofilms cause chronic infections because they show increased tolerance to antibiotics and disinfectant chemicals as well as resisting phagocytosis...... and other components of the body's defence system. The persistence of, for example, staphylococcal infections related to foreign bodies is due to biofilm formation. Likewise, chronic Pseudomonas aeruginosa lung infection in cystic fibrosis patients is caused by biofilm-growing mucoid strains....... Characteristically, gradients of nutrients and oxygen exist from the top to the bottom of biofilms and these gradients are associated with decreased bacterial metabolic activity and increased doubling times of the bacterial cells; it is these more or less dormant cells that are responsible for some of the tolerance...

  6. Antibiotic tolerance and microbial biofilms

    DEFF Research Database (Denmark)

    Folkesson, Anders

    Increased tolerance to antimicrobial agents is thought to be an important feature of microbes growing in biofilms. We study the dynamics of antibiotic action within hydrodynamic flow chamber biofilms of Escherichia coli and Pseudomonas aeruginosa using isogenic mutants and fluorescent gene...... expression reporters and we address the question of how biofilm organization affects antibiotic susceptibility. The dynamics of microbial killing is monitored by viable count determination, and confocal laser microscopy. Our work shows that the apparent increased antibiotic tolerance is due to the formation...... of antibiotic tolerant subpopulations within the biofilm. The formation of these subpopulations is highly variable and dependent on the antibiotic used, the biofilm structural organization and the induction of specific tolerance mechanisms....

  7. Isolate-specific effects of patulin, penicillic Acid and EDTA on biofilm formation and growth of dental unit water line biofilm isolates.

    Science.gov (United States)

    Liaqat, Iram; Bachmann, Robert Thomas; Sabri, Anjum Nasim; Edyvean, Robert G J

    2010-08-01

    Dental unit water line (DUWL) contamination by opportunistic pathogens has its significance in nosocomial infection of patients, health care workers, and life-threatening infections to immunocompromized persons. Recently, the quorum sensing (QS) system of DUWL isolates has been found to affect their biofilm-forming ability, making it an attractive target for antimicrobial therapy. In this study, the effect of two quorum-sensing inhibitory compounds (patulin; PAT, penicillic acid; PA) and EDTA on planktonic growth, AI-2 signalling and in vitro biofilm formation of Pseudomonas aeruginosa, Achromobacter xylosoxidans and Achromobacter sp. was monitored. Vibrio harveyi BB170 bioassay and crystal violet staining methods were used to detect the AI-2 monitoring and biofilm formation in DUWL isolates, respectively. The V. harveyi BB170 bioassay failed to induce bioluminescence in A. xylosoxidans and Achromobacter sp., while P. aeruginosa showed AI-2 like activity suggesting the need of some pretreatments prior to bioassay. All strains were found to form biofilms within 72 h of incubation. The QSIs/EDTA combination have isolate-specific effects on biofilm formation and in some cases it stimulated biofilm formation as often as it was inhibited. However, detailed information about the anti-biofilm effect of these compounds is still lacking.

  8. Inhibitory effects of ZnO nanoparticles on aerobic wastewater biofilms from oxygen concentration profiles determined by microelectrodes

    International Nuclear Information System (INIS)

    Hou, Jun; Miao, Lingzhan; Wang, Chao; Wang, Peifang; Ao, Yanhui; Qian, Jin; Dai, Shanshan

    2014-01-01

    Highlights: • Temporal and spatial inhibitory effects of ZnO NPs on biofilms were investigated. • 50 mg/L nano-ZnO inhibited the microbial activities only in biofilm outer layer. • Adsorbed ZnO NPs had no adverse effects on the cell membrane integrity of biofilms. • Dissolution of ZnO NPs to toxic zinc ions was the main mechanism of toxicity. - Abstract: The presence of ZnO NPs in waste streams can negatively affect the efficiency of biological nutrient removal from wastewater. However, details of the toxic effects of ZnO NPs on microbial activities of wastewater biofilms have not yet been reported. In this study, the temporal and spatial inhibitory effects of ZnO NPs on the O 2 respiration activities of aerobic wastewater biofilms were investigated using an O 2 microelectrode. The resulting time–course microelectrode measurements demonstrated that ZnO NPs inhibited O 2 respiration within 2 h. The spatial distributions of net specific O 2 respiration were determined in biofilms with and without treatment of 5 or 50 mg/L ZnO NPs. The results showed that 50 mg/L of nano-ZnO inhibited the microbial activities only in the outer layer (∼200 μm) of the biofilms, and bacteria present in the deeper parts of the biofilms became even more active. Scanning electron microscopy (SEM) analysis showed that the ZnO NPs were adsorbed onto the biofilm, but these NPs had no adverse effects on the cell membrane integrity of the biofilms. It was found that the inhibition of O 2 respiration induced by higher concentrations of ZnO NPs (50 mg/L) was mainly due to the release of zinc ions by dissolution of the ZnO NPs

  9. Inhibitory effects of ZnO nanoparticles on aerobic wastewater biofilms from oxygen concentration profiles determined by microelectrodes

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Jun [Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098 (China); College of Environment, Hohai University, Nanjing 210098 (China); Miao, Lingzhan, E-mail: mlz1988@126.com [Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098 (China); College of Environment, Hohai University, Nanjing 210098 (China); Wang, Chao, E-mail: hhuhjy973@126.com [Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098 (China); College of Environment, Hohai University, Nanjing 210098 (China); Wang, Peifang; Ao, Yanhui; Qian, Jin; Dai, Shanshan [Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098 (China); College of Environment, Hohai University, Nanjing 210098 (China)

    2014-07-15

    Highlights: • Temporal and spatial inhibitory effects of ZnO NPs on biofilms were investigated. • 50 mg/L nano-ZnO inhibited the microbial activities only in biofilm outer layer. • Adsorbed ZnO NPs had no adverse effects on the cell membrane integrity of biofilms. • Dissolution of ZnO NPs to toxic zinc ions was the main mechanism of toxicity. - Abstract: The presence of ZnO NPs in waste streams can negatively affect the efficiency of biological nutrient removal from wastewater. However, details of the toxic effects of ZnO NPs on microbial activities of wastewater biofilms have not yet been reported. In this study, the temporal and spatial inhibitory effects of ZnO NPs on the O{sub 2} respiration activities of aerobic wastewater biofilms were investigated using an O{sub 2} microelectrode. The resulting time–course microelectrode measurements demonstrated that ZnO NPs inhibited O{sub 2} respiration within 2 h. The spatial distributions of net specific O{sub 2} respiration were determined in biofilms with and without treatment of 5 or 50 mg/L ZnO NPs. The results showed that 50 mg/L of nano-ZnO inhibited the microbial activities only in the outer layer (∼200 μm) of the biofilms, and bacteria present in the deeper parts of the biofilms became even more active. Scanning electron microscopy (SEM) analysis showed that the ZnO NPs were adsorbed onto the biofilm, but these NPs had no adverse effects on the cell membrane integrity of the biofilms. It was found that the inhibition of O{sub 2} respiration induced by higher concentrations of ZnO NPs (50 mg/L) was mainly due to the release of zinc ions by dissolution of the ZnO NPs.

  10. Impact of Hydrodynamics on Oral Biofilm Strength

    NARCIS (Netherlands)

    Paramonova, E.; Kalmykowa, O. J.; van der Mei, H. C.; Busscher, H. J.; Sharma, P. K.

    2009-01-01

    Mechanical removal of oral biofilms is ubiquitously accepted as the best way to prevent caries and periodontal diseases. Removal effectiveness strongly depends on biofilm strength. To investigate the influence of hydrodynamics on oral biofilm strength, we grew single- and multi-species biofilms of

  11. Confocal microscopy imaging of the biofilm matrix

    DEFF Research Database (Denmark)

    Schlafer, Sebastian; Meyer, Rikke L

    2017-01-01

    The extracellular matrix is an integral part of microbial biofilms and an important field of research. Confocal laser scanning microscopy is a valuable tool for the study of biofilms, and in particular of the biofilm matrix, as it allows real-time visualization of fully hydrated, living specimens...... the concentration of solutes and the diffusive properties of the biofilm matrix....

  12. Oral Biofilm Architecture on Natural Teeth

    NARCIS (Netherlands)

    Zijnge, Vincent; van Leeuwen, M. Barbara M.; Degener, John E.; Abbas, Frank; Thurnheer, Thomas; Gmuer, Rudolf; Harmsen, Hermie J. M.

    2010-01-01

    Periodontitis and caries are infectious diseases of the oral cavity in which oral biofilms play a causative role. Moreover, oral biofilms are widely studied as model systems for bacterial adhesion, biofilm development, and biofilm resistance to antibiotics, due to their widespread presence and

  13. Bacterial biofilms: prokaryotic adventures in multicellularity

    DEFF Research Database (Denmark)

    Webb, J.S.; Givskov, Michael Christian; Kjelleberg, S.

    2003-01-01

    The development of bacterial biofilms includes both the initial social behavior of undifferentiated cells, as well as cell death and differentiation in the mature biofilm, and displays several striking similarities with higher organisms. Recent advances in the field provide new insight...... into differentiation and cell death events in bacterial biofilm development and propose that biofilms have an unexpected level of multicellularity....

  14. Control of bacterial biofilm growth on surfaces by nanostructural mechanics and geometry

    International Nuclear Information System (INIS)

    Epstein, A K; Hochbaum, A I; Kim, Philseok; Aizenberg, J

    2011-01-01

    Surface-associated communities of bacteria, called biofilms, pervade natural and anthropogenic environments. Mature biofilms are resistant to a wide range of antimicrobial treatments and therefore pose persistent pathogenic threats. The use of surface chemistry to inhibit biofilm growth has been found to only transiently affect initial attachment. In this work, we investigate the tunable effects of physical surface properties, including high-aspect-ratio (HAR) surface nanostructure arrays recently reported to induce long-range spontaneous spatial patterning of bacteria on the surface. The functional parameters and length scale regimes that control such artificial patterning for the rod-shaped pathogenic species Pseudomonas aeruginosa are elucidated through a combinatorial approach. We further report a crossover regime of biofilm growth on a HAR nanostructured surface versus the nanostructure effective stiffness. When the 'softness' of the hair-like nanoarray is increased beyond a threshold value, biofilm growth is inhibited as compared to a flat control surface. This result is consistent with the mechanoselective adhesion of bacteria to surfaces. Therefore by combining nanoarray-induced bacterial patterning and modulating the effective stiffness of the nanoarray—thus mimicking an extremely compliant flat surface—bacterial mechanoselective adhesion can be exploited to control and inhibit biofilm growth.

  15. Effect of LongZhang Gargle on Biofilm Formation and Acidogenicity of Streptococcus mutans In Vitro

    Directory of Open Access Journals (Sweden)

    Yutao Yang

    2016-01-01

    Full Text Available Streptococcus mutans, with the ability of high-rate acid production and strong biofilm formation, is considered the predominant bacterial species in the pathogenesis of human dental caries. Natural products which may be bioactive against S. mutans have become a hot spot to researches to control dental caries. LongZhang Gargle, completely made from Chinese herbs, was investigated for its effects on acid production and biofilm formation by S. mutans in this study. The results showed an antimicrobial activity of LongZhang Gargle against S. mutans planktonic growth at the minimum inhibitory concentration (MIC of 16% and minimum bactericidal concentration (MBC of 32%. Acid production was significantly inhibited at sub-MIC concentrations. Biofilm formation was also significantly disrupted, and 8% was the minimum concentration that resulted in at least 50% inhibition of biofilm formation (MBIC50. A scanning electron microscopy (SEM showed an effective disruption of LongZhang Gargle on S. mutans biofilm integrity. In addition, a confocal laser scanning microscopy (CLSM suggested that the extracellular polysaccharides (EPS synthesis could be inhibited by LongZhang Gargle at a relatively low concentration. These findings suggest that LongZhang Gargle may be a promising natural anticariogenic agent in that it suppresses planktonic growth, acid production, and biofilm formation against S. mutans.

  16. Growing and analyzing biofilms in flow chambers

    DEFF Research Database (Denmark)

    Tolker-Nielsen, Tim; Sternberg, Claus

    2011-01-01

    This unit describes the setup of flow chamber systems for the study of microbial biofilms, and methods for the analysis of structural biofilm formation. Use of flow chambers allows direct microscopic investigation of biofilm formation. The biofilms in flow chambers develop under hydrodynamic......, and disassembly and cleaning of the system. In addition, embedding and fluorescent in situ hybridization of flow chamber-grown biofilms are addressed....

  17. Preventive effects of a phospholipid polymer coating on PMMA on biofilm formation by oral streptococci

    Science.gov (United States)

    Shibata, Yukie; Yamashita, Yoshihisa; Tsuru, Kanji; Ishihara, Kazuhiko; Fukazawa, Kyoko; Ishikawa, Kunio

    2016-12-01

    The regulation of biofilm formation on dental materials such as denture bases is key to oral health. Recently, a biocompatible phospholipid polymer, poly(2-methacryloyloxyethyl phosphorylcholine-co-n-butyl methacrylate) (PMB) coating, was reported to inhibit sucrose-dependent biofilm formation by Streptococcus mutans, a cariogenic bacterium, on the surface of poly(methyl methacrylate) (PMMA) denture bases. However, S. mutans is a minor component of the oral microbiome and does not play an important role in biofilm formation in the absence of sucrose. Other, more predominant oral streptococci must play an indispensable role in sucrose-independent biofilm formation. In the present study, the effect of PMB coating on PMMA was evaluated using various oral streptococci that are known to be initial colonizers during biofilm formation on tooth surfaces. PMB coating on PMMA drastically reduced sucrose-dependent tight biofilm formation by two cariogenic bacteria (S. mutans and Streptococcus sobrinus), among seven tested oral streptococci, as described previously [N. Takahashi, F. Iwasa, Y. Inoue, H. Morisaki, K. Ishihara, K. Baba, J. Prosthet. Dent. 112 (2014) 194-203]. Streptococci other than S. mutans and S. sobrinus did not exhibit tight biofilm formation even in the presence of sucrose. On the other hand, all seven species of oral streptococci exhibited distinctly reduced glucose-dependent soft biofilm retention on PMB-coated PMMA. We conclude that PMB coating on PMMA surfaces inhibits biofilm attachment by initial colonizer oral streptococci, even in the absence of sucrose, indicating that PMB coating may help maintain clean conditions on PMMA surfaces in the oral cavity.

  18. MRSA decolonization failure—are biofilms the missing link?

    Directory of Open Access Journals (Sweden)

    Frank Günther

    2017-03-01

    Full Text Available Abstract Background Device-associated infections due to biofilm-producing methicillin-resistant Staphylococcus aureus (MRSA have been recently associated with the failure of antibiotic treatment and decolonization measures. The goal of our study was to evaluate the extent to which the formation of biofilms influenced the efficacy of topical decolonization agents or disinfectants such as mupirocin (MUP, octenidine (OCT, chlorhexidine (CHG, polyhexanide (POL, and chloroxylenol (CLO. Methods Bacterial killing in biofilms by the disinfectants and MUP was determined as the reduction [%] in metabolic activity determined by a biofilm viability assay that uses kinetic analysis of metabolic activity. The test substances were diluted in water with standardized hardness (WSH at 25 °C at the standard concentration as well as half the standard concentration to demonstrate the dilution effects in a practical setting. The tested concentrations were: CHG 1%, 2%; OCT 0.1%, 0.05%; PH 0.04%, 0.02%; and CLO 0.12%, 0.24%. A test organism suspension, 1 mL containing ~1 × 109 bacterial cells/mL, and 1 mL of sterile WSH were mixed and incubated for six different exposure times (15 s, 1, 3, 5, 10 and 20 min after the test substance was added. Additionally, the bactericidal effects of all substances were tested on planktonic bacteria and measured as the log10 reduction. Results The disinfectants OCT and CHG showed good efficacy in inhibiting MRSA in biofilms with reduction rates of 94 ± 1% and 91 ± 1%, respectively. POL, on the other hand, had a maximum efficacy of only 81 ± 7%. Compared to the tested disinfectants, MUP showed a significantly lower efficacy with <20% inhibition (p < .05. Bactericidal effects were the greatest for CHG (log10 reduction of 9.0, followed by OCT (7.7, POL (5.1, and CLO (6.8. MUP, however, showed a very low bactericidal effect of only 2.1. Even when the exposure time was increased to 24 h, 2% MUP did not show

  19. Conductive properties of methanogenic biofilms.

    Science.gov (United States)

    Li, Cheng; Lesnik, Keaton Larson; Liu, Hong

    2018-02-01

    Extracellular electron transfer between syntrophic partners needs to be efficiently maintained in methanogenic environments. Direct extracellular electron transfer via electrical current is an alternative to indirect hydrogen transfer but requires construction of conductive extracellular structures. Conductive mechanisms and relationship between conductivity and the community composition in mixed-species methanogenic biofilms are not well understood. The present study investigated conductive behaviors of methanogenic biofilms and examined the correlation between biofilm conductivity and community composition between different anaerobic biofilms enriched from the same inoculum. Highest conductivity observed in methanogenic biofilms was 71.8±4.0μS/cm. Peak-manner response of conductivity upon changes over a range of electrochemical potentials suggests that electron transfer in methanogenic biofilms occurs through redox driven super-exchange. The strong correlation observed between biofilm conductivity and Geobacter spp. in the metabolically diverse anaerobic communities suggests that the efficiency of DEET may provide pressure for microbial communities to select for species that can produce electrical conduits. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Dendrimers and polyamino-phenolic ligands: activity of new molecules against Legionella pneumophila biofilms.

    Directory of Open Access Journals (Sweden)

    Elisa eAndreozzi

    2016-03-01

    Full Text Available Legionnaires’ disease is a potentially fatal pneumonia caused by Legionella pneumophila, an aquatic bacterium often found within the biofilm niche. In man-made water systems microbial biofilms increase the resistance of legionella to disinfection, posing a significant threat to public health. Disinfection methods currently used in water systems have been shown to be ineffective against legionella over the long-term, allowing recolonization by the biofilm-protected microorganisms. In this study, the anti-biofilm activity of previously fabricated polyamino-phenolic ligands and polyamidoamine dendrimers was investigated against legionella mono-species and multi-species biofilms formed by L. pneumophila in association with other bacteria that can be found in tap water (Aeromonas hydrophila, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae. Bacterial ability to form biofilms was verified using a crystal violet colorimetric assay and testing cell viability by real-time quantitative PCR and Plate Count assay. The concentration of the chemicals tested as anti-biofilm agents was chosen based on cytotoxicity assays: the highest non-cytotoxic chemical concentration was used for biofilm inhibition assays, with dendrimer concentration ten-fold higher than polyamino-phenolic ligands. While Macrophen and Double Macrophen were the most active substances among polyamino-phenolic ligands, dendrimers were overall two-fold more effective than all other compounds with a reduction up to 85% and 73% of legionella and multi-species biofilms, respectively. Chemical interaction with matrix molecules is hypothesized, based on SEM images and considering the low or absent anti-microbial activity on planktonic bacteria showed by flow cytometry. These data suggest that the studied compounds, especially dendrimers, could be considered as novel molecules in the design of research projects aimed at the development of efficacious anti-biofilm disinfection

  1. Metabolic activity of Streptococcus mutans biofilms and gene expression during exposure to xylitol and sucrose.

    Science.gov (United States)

    Decker, Eva-Maria; Klein, Christian; Schwindt, Dimitri; von Ohle, Christiane

    2014-12-01

    The objective of the study was to analyse Streptococcus mutans biofilms grown under different dietary conditions by using multifaceted methodological approaches to gain deeper insight into the cariogenic impact of carbohydrates. S. mutans biofilms were generated during a period of 24 h in the following media: Schaedler broth as a control medium containing endogenous glucose, Schaedler broth with an additional 5% sucrose, and Schaedler broth supplemented with 1% xylitol. The confocal laser scanning microscopy (CLSM)-based analyses of the microbial vitality, respiratory activity (5-cyano-2,3-ditolyl tetrazolium chloride, CTC) and production of extracellular polysaccharides (EPS) were performed separately in the inner, middle and outer biofilm layers. In addition to the microbiological sample testing, the glucose/sucrose consumption of the biofilm bacteria was quantified, and the expression of glucosyltransferases and other biofilm-associated genes was investigated. Xylitol exposure did not inhibit the viability of S. mutans biofilms, as monitored by the following experimental parameters: culture growth, vitality, CTC activity and EPS production. However, xylitol exposure caused a difference in gene expression compared to the control. GtfC was upregulated only in the presence of xylitol. Under xylitol exposure, gtfB was upregulated by a factor of 6, while under sucrose exposure, it was upregulated by a factor of three. Compared with glucose and xylitol, sucrose increased cell vitality in all biofilm layers. In all nutrient media, the intrinsic glucose was almost completely consumed by the cells of the S. mutans biofilm within 24 h. After 24 h of biofilm formation, the multiparametric measurements showed that xylitol in the presence of glucose caused predominantly genotypic differences but did not induce metabolic differences compared to the control. Thus, the availability of dietary carbohydrates in either a pure or combined form seems to affect the

  2. Metabolic activity of Streptococcus mutans biofilms and gene expression during exposure to xylitol and sucrose

    Institute of Scientific and Technical Information of China (English)

    Eva-Maria Decker; Christian Klein; Dimitri Schwindt; Christiane von Ohle

    2014-01-01

    The objective of the study was to analyse Streptococcus mutans biofilms grown under different dietary conditions by using multifaceted methodological approaches to gain deeper insight into the cariogenic impact of carbohydrates. S. mutans biofilms were generated during a period of 24 h in the following media:Schaedler broth as a control medium containing endogenous glucose, Schaedler broth with an additional 5%sucrose, and Schaedler broth supplemented with 1%xylitol. The confocal laser scanning microscopy (CLSM)-based analyses of the microbial vitality, respiratory activity (5-cyano-2,3-ditolyl tetrazolium chloride, CTC) and production of extracellular polysaccharides (EPS) were performed separately in the inner, middle and outer biofilm layers. In addition to the microbiological sample testing, the glucose/sucrose consumption of the biofilm bacteria was quantified, and the expression of glucosyltransferases and other biofilm-associated genes was investigated. Xylitol exposure did not inhibit the viability of S. mutans biofilms, as monitored by the following experimental parameters:culture growth, vitality, CTC activity and EPS production. However, xylitol exposure caused a difference in gene expression compared to the control. GtfC was upregulated only in the presence of xylitol. Under xylitol exposure, gtfB was upregulated by a factor of 6, while under sucrose exposure, it was upregulated by a factor of three. Compared with glucose and xylitol, sucrose increased cell vitality in all biofilm layers. In all nutrient media, the intrinsic glucose was almost completely consumed by the cells of the S. mutans biofilm within 24 h. After 24 h of biofilm formation, the multiparametric measurements showed that xylitol in the presence of glucose caused predominantly genotypic differences but did not induce metabolic differences compared to the control. Thus, the availability of dietary carbohydrates in either a pure or combined form seems to affect the cariogenic potential

  3. Morphological Change and Decreasing Transfer Rate of Biofilm-Featured Listeria monocytogenes EGDe.

    Science.gov (United States)

    Lee, Yuejia; Wang, Chinling

    2017-03-01

    Listeria monocytogenes , a lethal foodborne pathogen, has the ability to resist the hostile food processing environment and thus frequently contaminates ready-to-eat foods during processing. It is commonly accepted that the tendency of L. monocytogenes ' to generate biofilms on various surfaces enhances its resistance to the harshness of the food processing environment. However, the role of biofilm formation in the transferability of L. monocytogenes EGDe remains controversial. We examined the growth of Listeria biofilms on stainless steel surfaces and their effect on the transferability of L. monocytogenes EGDe. The experiments were a factorial 2 × 2 design with at least three biological replicates. Through scanning electron microscopy, a mature biofilm with intensive aggregates of cells was observed on the surface of stainless steel after 3 or 5 days of incubation, depending on the initial level of inoculation. During biofilm development, L. monocytogenes EGDe carried out binary fission vigorously before a mature biofilm was formed and subsequently changed its cellular morphology from rod shaped to sphere shaped. Furthermore, static biofilm, which was formed after 3 days of incubation at 25°C, significantly inhibited the transfer rate of L. monocytogenes EGDe from stainless steel blades to 15 bologna slices. During 7 days of storage at 4°C, however, bacterial growth rate was not significantly impacted by whether bacteria were transferred from biofilm and the initial concentrations of transferred bacteria on the slice. In conclusion, this study is the first to report a distinct change in morphology of L. monocytogenes EGDe at the late stage of biofilm formation. More importantly, once food is contaminated by L. monocytogenes EGDe, contamination proceeds independently of biofilm development and the initial level of contamination when food is stored at 4°C, even if contamination with L. monocytogenes EGDe was initially undetectable before storage.

  4. Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA isolates of swine origin form robust biofilms.

    Directory of Open Access Journals (Sweden)

    Tracy L Nicholson

    Full Text Available Methicillin-resistant Staphylococcus aureus (MRSA colonization of livestock animals is common and prevalence rates for pigs have been reported to be as high as 49%. Mechanisms contributing to the persistent carriage and high prevalence rates of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA strains in swine herds and production facilities have not been investigated. One explanation for the high prevalence of MRSA in swine herds is the ability of these organisms to exist as biofilms. In this report, the ability of swine LA-MRSA strains, including ST398, ST9, and ST5, to form biofilms was quantified and compared to several swine and human isolates. The contribution of known biofilm matrix components, polysaccharides, proteins and extracellular DNA (eDNA, was tested in all strains as well. All MRSA swine isolates formed robust biofilms similar to human clinical isolates. The addition of Dispersin B had no inhibitory effect on swine MRSA isolates when added at the initiation of biofilm growth or after pre-established mature biofilms formed. In contrast, the addition of proteinase K inhibited biofilm formation in all strains when added at the initiation of biofilm growth and was able to disperse pre-established mature biofilms. Of the LA-MRSA strains tested, we found ST398 strains to be the most sensitive to both inhibition of biofilm formation and dispersal of pre-formed biofilms by DNaseI. Collectively, these findings provide a critical first step in designing strategies to control or eliminate MRSA in swine herds.

  5. Novel approaches to mitigating bacterial biofilm formation and intercellular communication

    Science.gov (United States)

    Kasper, Stephen H.

    Long thought of as solitary single-cell organisms, it is now widely accepted that bacteria can act and cooperate as social organisms. Phenomena such as biofilm formation and quorum sensing (QS) are two intimately intertwined cooperative behaviors that significantly contribute to the pathogenesis of many bacteria. Biofilms are surface associated communities of bacteria encased in a secreted extracellular matrix, which provides several advantages over an individualized lifestyle, such as increased protection from antimicrobial agents as well as enhanced opportunity for the exchange of genetic material. Bacterial QS is a system of population-based communication through the production, sensing, and response to chemical signals, often controlling the expression of diverse virulence factors (e.g. toxins, proteases). Biofilm formation and QS are cooperative processes that are often leveraged as bacteria coordinate infection processes, and can therefore be novel targets for anti-infective treatments that differ from conventional antibiotic treatment. Our lab has previously identified a novel class of small molecules that inhibit biofilm formation and disrupt QS by the pathogenic bacterium Pseudomonas aeruginosa. These organosulfur-based compounds are either natural products or related derivatives of the tropical plant Petiveria alliacea. Because oral biofilm (e.g. dental plaque) is a major conduit of oral and systemic disease, and is also a site for horizontal transfer for genes encoding antibiotic resistance, there exists a need for novel strategies for inhibiting oral biofilm development. Therefore, a small library (˜50 compounds) of structural derivatives was developed and screened for their ability to inhibit biofilm formation by multiple orally associated bacteria. The screening effort uncovered several related compounds that inhibited oral biofilm development. To determine how natural product-based organosulfur compounds could be inducing QS inhibitory effects, an

  6. Biofilm models for the practitioner

    DEFF Research Database (Denmark)

    Morgenroth, Eberhard Friedrich; van Loosdrecht, M. C. M.; Wanner, O.

    2000-01-01

    Even though mathematical biofilm models are extensively used in biofilm research, there has been very little application of these models in the engineering practice so far. However, practitioners would be interested in models that can be used as tools to control plant operation under dynamic...... conditions or to help them handle complex interactions between particle removal, carbon oxidation, nitrification, denitrification and biological phosphorus removal. But even though there is a whole range of biofilm models available, it is difficult for the practitioner to select the appropriate modeling...

  7. 2-Furaldehyde diethyl acetal from tender coconut water (Cocos nucifera) attenuates biofilm formation and quorum sensing-mediated virulence of Chromobacterium violaceum and Pseudomonas aeruginosa.

    Science.gov (United States)

    Sethupathy, Sivasamy; Nithya, Chari; Pandian, Shunmugiah Karutha

    2015-01-01

    The aim of this study was to evaluate the anti-biofilm and quorum sensing inhibitory (QSI) potential of tender coconut water (TCW) against Chromobacterium violaceum and Pseudomonas aeruginosa. TCW significantly inhibited the QS regulated violacein, virulence factors and biofilm production without affecting their growth. qRT-PCR analysis revealed the down-regulation of autoinducer synthase, transcriptional regulator and virulence genes. Mass-spectrometric analysis of a petroleum ether extract of the TCW hydrolyte revealed that 2-furaldehyde diethyl acetal (2FDA) and palmitic acid (PA) are the major compounds. In vitro bioassays confirmed the ability of 2FDA to inhibit the biofilm formation and virulence factors. In addition, the combination of PA with 2FDA resulted in potent inhibition of biofilm formation and virulence factors. The results obtained strongly suggest that TCW can be exploited as a base for designing a novel antipathogenic drug formulation to treat biofilm mediated infections caused by P. aeruginosa.

  8. Time dependent enhanced resistance against antibiotics & metal salts by planktonic & biofilm form of Acinetobacter haemolyticus MMC 8 clinical isolate

    Directory of Open Access Journals (Sweden)

    Sharvari Vijaykumar Gaidhani

    2014-01-01

    Full Text Available Background & objectives: Available literature shows paucity of reports describing antibiotic and metal resistance profile of biofilm forming clinical isolates of Acinetobacter haemolyticus. The present study was undertaken to evaluate the antibiotic and metal resistance profile of Indian clinical isolate of A. haemolyticus MMC 8 isolated from human pus sample in planktonic and biofilm form. Methods: Antibiotic susceptibility and minimum inhibitory concentration were determined employing broth and agar dilution techniques. Biofilm formation was evaluated quantitatively by microtiter plate method and variation in complex architecture was determined by scanning electron microscopy. Minimum biofilm inhibiting concentration was checked by Calgary biofilm device. Results: Planktonic A. haemolyticus MMC 8 was sensitive to 14 antibiotics, AgNO 3 and HgC1 2 resistant to streptomycin and intermediately resistant to netilmycin and kanamycin. MMC 8 exhibited temporal variation in amount and structure of biofilm. There was 32 - 4000 and 4 - 256 fold increase in antibiotic and metal salt concentration, respectively to inhibit biofilm over a period of 72 h as against susceptible planktonic counterparts. Total viable count in the range of 10 5 -10 6 cfu / ml was observed on plating minimum biofilm inhibiting concentration on Muller-Hinton Agar plate without antimicrobial agents. Biofilm forming cells were several folds more resistant to antibiotics and metal salts in comparison to planktonic cells. Presence of unaffected residual cell population indicated presence of persister cells. Interpretation & conclusions: The results indicate that biofilm formation causes enhanced resistance against antibiotics and metal salts in otherwise susceptible planktonic A. haemolyticus MMC 8.

  9. Stratified growth in Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Werner, E.; Roe, F.; Bugnicourt, A.

    2004-01-01

    In this study, stratified patterns of protein synthesis and growth were demonstrated in Pseudomonas aeruginosa biofilms. Spatial patterns of protein synthetic activity inside biofilms were characterized by the use of two green fluorescent protein (GFP) reporter gene constructs. One construct...... synthesis was restricted to a narrow band in the part of the biofilm adjacent to the source of oxygen. The zone of active GFP expression was approximately 60 Am wide in colony biofilms and 30 Am wide in flow cell biofilms. The region of the biofilm in which cells were capable of elongation was mapped...... by treating colony biofilms with carbenicillin, which blocks cell division, and then measuring individual cell lengths by transmission electron microscopy. Cell elongation was localized at the air interface of the biofilm. The heterogeneous anabolic patterns measured inside these biofilms were likely a result...

  10. Novel method for quantitative estimation of biofilms

    DEFF Research Database (Denmark)

    Syal, Kirtimaan

    2017-01-01

    Biofilm protects bacteria from stress and hostile environment. Crystal violet (CV) assay is the most popular method for biofilm determination adopted by different laboratories so far. However, biofilm layer formed at the liquid-air interphase known as pellicle is extremely sensitive to its washing...... and staining steps. Early phase biofilms are also prone to damage by the latter steps. In bacteria like mycobacteria, biofilm formation occurs largely at the liquid-air interphase which is susceptible to loss. In the proposed protocol, loss of such biofilm layer was prevented. In place of inverting...... and discarding the media which can lead to the loss of the aerobic biofilm layer in CV assay, media was removed from the formed biofilm with the help of a syringe and biofilm layer was allowed to dry. The staining and washing steps were avoided, and an organic solvent-tetrahydrofuran (THF) was deployed...

  11. Propolis-Sahara honeys preparation exhibits antibacterial and anti-biofilm activity against bacterial biofims formed on urinary catheters

    Directory of Open Access Journals (Sweden)

    Saad Aissat

    2016-11-01

    Full Text Available Objective: To evaluate the antibacterial effect of Sahara honeys (SHs against bacterial biofilms formed on urinary catheters in combination with propolis-Sahara honeys (P-SHs. Methods: Three clinical isolates were subjected to biofilm detection methods. The antibacterial and anti-biofilm activity for SHs and P-SHs were determined using agar well diffusion and the percentage of biofilm inhibition (PBI methods. Results: The PBI for Gram-positive bacteria [Staphylococcus aureus (S. aureus] was in the range of 0%–20%, while PBI for Gram-negative bacteria [Pseudomonas aeruginosa and Escherichia coli (E. coli] were in range of 17%–57% and 16%–65%, respectively. The highest PBI (65% was produced by SH2 only on E. coli. In agar well diffusion assay, zones of inhibition ranged from 11–20 mm (S. aureus, 9–19 mm (Pseudomonas aeruginosa and 11–19 mm (E. coli. The highest inhibition (20 mm was produced by SH1 only on S. aureus. In addition, the treatment of SHs and P-SHs catheters with a polymicrobial biofilms reduced biofilm formation after 48 h exposure period. Conclussions: SHs and P-SHs applied as a natural agent can be used as a prophylactic agent to prevent the formation of in vitro biofilm.

  12. Synergistic Effect of 14-Alpha-Lipoyl Andrographolide and Various Antibiotics on the Formation of Biofilms and Production of Exopolysaccharide and Pyocyanin by Pseudomonas aeruginosa▿

    OpenAIRE

    Zeng, Xiangping; Liu, Xiangyang; Bian, Jiang; Pei, Gang; Dai, Huanqin; Polyak, Steven W.; Song, Fuhang; Ma, Li; Wang, Yuqiang; Zhang, Lixin

    2011-01-01

    Pseudomonas aeruginosa produces a biofilm that provides the bacteria with an effective barrier against antibiotics. Here, we investigated the synergy of various antibiotics with 14-alpha-lipoyl andrographolide (AL-1), focusing upon synthesis of the biofilm. AL-1 also inhibited the production of the exopolysaccharide and pyocyanin components. We propose that AL-1 may potentially serve as a cotherapy to combat P. aeruginosa.

  13. Synergistic effect of 14-alpha-lipoyl andrographolide and various antibiotics on the formation of biofilms and production of exopolysaccharide and pyocyanin by Pseudomonas aeruginosa.

    Science.gov (United States)

    Zeng, Xiangping; Liu, Xiangyang; Bian, Jiang; Pei, Gang; Dai, Huanqin; Polyak, Steven W; Song, Fuhang; Ma, Li; Wang, Yuqiang; Zhang, Lixin

    2011-06-01

    Pseudomonas aeruginosa produces a biofilm that provides the bacteria with an effective barrier against antibiotics. Here, we investigated the synergy of various antibiotics with 14-alpha-lipoyl andrographolide (AL-1), focusing upon synthesis of the biofilm. AL-1 also inhibited the production of the exopolysaccharide and pyocyanin components. We propose that AL-1 may potentially serve as a cotherapy to combat P. aeruginosa.

  14. Hydrodynamic dispersion within porous biofilms

    KAUST Repository

    Davit, Y.; Byrne, H.; Osborne, J.; Pitt-Francis, J.; Gavaghan, D.; Quintard, M.

    2013-01-01

    Many microorganisms live within surface-associated consortia, termed biofilms, that can form intricate porous structures interspersed with a network of fluid channels. In such systems, transport phenomena, including flow and advection, regulate

  15. Bacterial biofilms and antibiotic resistance

    Directory of Open Access Journals (Sweden)

    Liliana Caldas-Arias

    2015-04-01

    Full Text Available Biofilms give to bacteria micro-environmental benefits; confers protection against antimicrobials. Bacteria have antibiotic resistance by conventional and unusual mechanisms leading to delayed wound healing, to increase recurrent chronic infections and nosocomial contamination of medical devices. Objective: This narrative review aims to introduce the characteristics of Bacteria-biofilms, antimicrobial resistance mechanisms and potential alternatives for prevention and control of its formation. Methods: Search strategy was performed on records: PubMed / Medline, Lilacs, Redalyc; with suppliers such as EBSCO and thesaurus MeSH and DeCS. Conclusions: Knowledge and research performance of biofilm bacteria are relevant in the search of technology for detection and measuring sensitivity to antibiotics. The identification of Bacterial-biofilms needs no-traditional microbiological diagnosis.

  16. Exploiting social evolution in biofilms

    DEFF Research Database (Denmark)

    Boyle, Kerry E; Heilmann, Silja; van Ditmarsch, Dave

    2013-01-01

    Bacteria are highly social organisms that communicate via signaling molecules, move collectively over surfaces and make biofilm communities. Nonetheless, our main line of defense against pathogenic bacteria consists of antibiotics-drugs that target individual-level traits of bacterial cells...... and thus, regrettably, select for resistance against their own action. A possible solution lies in targeting the mechanisms by which bacteria interact with each other within biofilms. The emerging field of microbial social evolution combines molecular microbiology with evolutionary theory to dissect...... the molecular mechanisms and the evolutionary pressures underpinning bacterial sociality. This exciting new research can ultimately lead to new therapies against biofilm infections that exploit evolutionary cheating or the trade-off between biofilm formation and dispersal....

  17. Biofilms: Community Behavior by Bacteria

    Indian Academy of Sciences (India)

    IAS Admin

    United we stand, divided we fall. This is a ... controls biofilm development, swarming motility and the produc- ... thought that the absence of overt gut flora upsets the balance .... there are several risks of integration which makes this strategy.

  18. Compaction and relaxation of biofilms

    KAUST Repository

    Valladares Linares, R.; Wexler, A. D.; Bucs, Szilard; Dreszer, C.; Zwijnenburg, A.; Flemming, H. C.; Kruithof, J. C.; Vrouwenvelder, Johannes S.

    2015-01-01

    Operation of membrane systems for water treatment can be seriously hampered by biofouling. A better characterization of biofilms in membrane systems and their impact on membrane performance may help to develop effective biofouling control strategies

  19. Involvement of T6 pili in biofilm formation by serotype M6 Streptococcus pyogenes.

    Science.gov (United States)

    Kimura, Keiji Richard; Nakata, Masanobu; Sumitomo, Tomoko; Kreikemeyer, Bernd; Podbielski, Andreas; Terao, Yutaka; Kawabata, Shigetada

    2012-02-01

    The group A streptococcus (GAS) Streptococcus pyogenes is known to cause self-limiting purulent infections in humans. The role of GAS pili in host cell adhesion and biofilm formation is likely fundamental in early colonization. Pilus genes are found in the FCT (fibronectin-binding protein, collagen-binding protein, and trypsin-resistant antigen) genomic region, which has been classified into nine subtypes based on the diversity of gene content and nucleotide sequence. Several epidemiological studies have indicated that FCT type 1 strains, including serotype M6, produce large amounts of monospecies biofilm in vitro. We examined the direct involvement of pili in biofilm formation by serotype M6 clinical isolates. In the majority of tested strains, deletion of the tee6 gene encoding pilus shaft protein T6 compromised the ability to form biofilm on an abiotic surface. Deletion of the fctX and srtB genes, which encode pilus ancillary protein and class C pilus-associated sortase, respectively, also decreased biofilm formation by a representative strain. Unexpectedly, these mutant strains showed increased bacterial aggregation compared with that of the wild-type strain. When the entire FCT type 1 pilus region was ectopically expressed in serotype M1 strain SF370, biofilm formation was promoted and autoaggregation was inhibited. These findings indicate that assembled FCT type 1 pili contribute to biofilm formation and also function as attenuators of bacterial aggregation. Taken together, our results show the potential role of FCT type 1 pili in the pathogenesis of GAS infections.

  20. Adhesion and removal kinetics of Bacillus cereus biofilms on Ni-PTFE modified stainless steel.

    Science.gov (United States)

    Huang, Kang; McLandsborough, Lynne A; Goddard, Julie M

    2016-01-01

    Biofilm control remains a challenge to food safety. A well-studied non-fouling coating involves codeposition of polytetrafluoroethylene (PTFE) during electroless plating. This coating has been reported to reduce foulant build-up during pasteurization, but opportunities remain in demonstrating its efficacy in inhibiting biofilm formation. Herein, the initial adhesion, biofilm formation, and removal kinetics of Bacillus cereus on Ni-PTFE-modified stainless steel (SS) are characterized. Coatings lowered the surface energy of SS and reduced biofilm formation by > 2 log CFU cm(-2). Characterization of the kinetics of biofilm removal during cleaning demonstrated improved cleanability on the Ni-PTFE coated steel. There was no evidence of biofilm after cleaning by either solution on the Ni-PTFE coated steel, whereas more than 3 log and 1 log CFU cm(-2) of bacteria remained on the native steel after cleaning with water and an alkaline cleaner, respectively. This work demonstrates the potential application of Ni-PTFE non-fouling coatings on SS to improve food safety by reducing biofilm formation and improving the cleaning efficiency of food processing equipment.

  1. Selective labelling and eradication of antibiotic-tolerant bacterial populations in Pseudomonas aeruginosa biofilms.

    Science.gov (United States)

    Chua, Song Lin; Yam, Joey Kuok Hoong; Hao, Piliang; Adav, Sunil S; Salido, May Margarette; Liu, Yang; Givskov, Michael; Sze, Siu Kwan; Tolker-Nielsen, Tim; Yang, Liang

    2016-02-19

    Drug resistance and tolerance greatly diminish the therapeutic potential of antibiotics against pathogens. Antibiotic tolerance by bacterial biofilms often leads to persistent infections, but its mechanisms are unclear. Here we use a proteomics approach, pulsed stable isotope labelling with amino acids (pulsed-SILAC), to quantify newly expressed proteins in colistin-tolerant subpopulations of Pseudomonas aeruginosa biofilms (colistin is a 'last-resort' antibiotic against multidrug-resistant Gram-negative pathogens). Migration is essential for the formation of colistin-tolerant biofilm subpopulations, with colistin-tolerant cells using type IV pili to migrate onto the top of the colistin-killed biofilm. The colistin-tolerant cells employ quorum sensing (QS) to initiate the formation of new colistin-tolerant subpopulations, highlighting multicellular behaviour in antibiotic tolerance development. The macrolide erythromycin, which has been previously shown to inhibit the motility and QS of P. aeruginosa, boosts biofilm eradication by colistin. Our work provides insights on the mechanisms underlying the formation of antibiotic-tolerant populations in bacterial biofilms and indicates research avenues for designing more efficient treatments against biofilm-associated infections.

  2. Synergistic effect on biofilm formation between Fusobacterium nucleatum and Capnocytophaga ochracea.

    Science.gov (United States)

    Okuda, Tamaki; Okuda, Katsuji; Kokubu, Eitoyo; Kawana, Tomoko; Saito, Atsushi; Ishihara, Kazuyuki

    2012-02-01

    The formation of dental plaque biofilm by specific Gram-negative rods and spirochetes plays an important role in the development of periodontal disease. The aim of this study was to characterize biofilm formation by Fusobacterium nucleatum and Capnocytophaga ochracea. Coaggregation between F. nucleatum and Capnocytophaga species was determined by visual assay. Biofilm formation was assessed by crystal violet staining. Enhancement of biofilm formation by F. nucleatum via soluble factor of C. ochracea was evaluated by addition of culture supernatant and a two-compartment separated co-culture system. Production of autoinducer-2 by the tested organisms was evaluated using Vibrio harveyi BB170. F. nucleatum strains coaggregated with C. ochracea ATCC 33596 or ONO-26 strains. Ethylenediamine tetraacetic acid, N-acetyl-d-galactosamine or lysine inhibited coaggregation. Heating or proteinase K treatment of F. nucleatum cells affected coaggregation, whereas the same treatment of C. ochracea cells did not. Co-culture of F. nucleatum with C. ochracea in the same well resulted in a statistically significant increase in biofilm formation. Enhancement of F. nucleatum biofilm formation by a soluble component of C. ochracea was observed using the two-compartment co-culture system (P culture supernatant of C. ochracea (P < 0.01). The present findings indicate that induction of coaggregation and intracellular interaction by release of a diffusible molecule by C. ochracea play a significant role in the formation of biofilm by F. nucleatum and C. ochracea. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Physical abrasion method using submerged spike balls to remove algal biofilm from photobioreactors.

    Science.gov (United States)

    Nawar, Azra; Khoja, Asif Hussain; Akbar, Naveed; Ansari, Abeera Ayaz; Qayyum, Muneeb; Ali, Ehsan

    2017-12-02

    A major factor in practical application of photobioreactors (PBR) is the adhesion of algal cells onto their inner walls. Optimized algal growth requires an adequate sunlight for the photosynthesis and cell growth. Limitation in light exposure adversely affects the algal biomass yield. The removal of the biofilm from PBR is a challenging and expansive task. This study was designed to develop an inexpensive technique to prevent adhesion of algal biofilm on tubular PBR to ensure high efficiency of light utilization. Rubber balls with surface projections were introduced into the reactor, to remove the adherent biofilm by physical abrasion technique. The floatation of spike balls created a turbulent flow, thereby inhibiting further biofilm formation. The parameters such as, specific growth rate and doubling time of the algae before introducing the balls were 0.451 day -1 and 1.5 days respectively. Visible biofilm impeding light transmission was formed by 15-20 days. The removal of the biofilm commenced immediately after the introduction of the spike balls with visibly reduced deposits in 3 days. This was also validated by enhance cell count (6.95 × 106 cells mL -1 ) in the medium. The employment of spike balls in PBR is an environmental friendly and economical method for the removal of biofilm.

  4. Selective labelling and eradication of antibiotic-tolerant bacterial populations in Pseudomonas aeruginosa biofilms

    Science.gov (United States)

    Chua, Song Lin; Yam, Joey Kuok Hoong; Hao, Piliang; Adav, Sunil S.; Salido, May Margarette; Liu, Yang; Givskov, Michael; Sze, Siu Kwan; Tolker-Nielsen, Tim; Yang, Liang

    2016-01-01

    Drug resistance and tolerance greatly diminish the therapeutic potential of antibiotics against pathogens. Antibiotic tolerance by bacterial biofilms often leads to persistent infections, but its mechanisms are unclear. Here we use a proteomics approach, pulsed stable isotope labelling with amino acids (pulsed-SILAC), to quantify newly expressed proteins in colistin-tolerant subpopulations of Pseudomonas aeruginosa biofilms (colistin is a ‘last-resort' antibiotic against multidrug-resistant Gram-negative pathogens). Migration is essential for the formation of colistin-tolerant biofilm subpopulations, with colistin-tolerant cells using type IV pili to migrate onto the top of the colistin-killed biofilm. The colistin-tolerant cells employ quorum sensing (QS) to initiate the formation of new colistin-tolerant subpopulations, highlighting multicellular behaviour in antibiotic tolerance development. The macrolide erythromycin, which has been previously shown to inhibit the motility and QS of P. aeruginosa, boosts biofilm eradication by colistin. Our work provides insights on the mechanisms underlying the formation of antibiotic-tolerant populations in bacterial biofilms and indicates research avenues for designing more efficient treatments against biofilm-associated infections. PMID:26892159

  5. Anti-Biofilm and Antivirulence Activities of Metabolites from Plectosphaerella cucumerina against Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Jinwei Zhou

    2017-05-01

    Full Text Available This study reported the efficacy of the metabolites of Plectosphaerella cucumerina, one phyllosphere fungus from Orychophragmus violaceus, against Pseudomonas aeruginosa quorum sensing (QS and QS-regulated biofilms. The minimum inhibitory concentration (MIC of the ethyl acetate (EtOAc extract from P. cucumerina against P. aeruginosa PAO1 was 1.25 mg mL−1. At sub-MIC concentrations, P. cucumerina extract (0.25–1 mg mL−1 not only inhibited biofilm formation but also disrupted preformed biofilms of P. aeruginosa PAO1 without affecting its growth. Fluorescence and scanning electron microscope (SEM showed architectural disruption of the biofilms when treated with P. cucumerina metabolites. Further investigation demonstrated that metabolites in P. cucumerina attenuated the QS-dependent virulence factors. LC-MS/MS spectra coupled with experimentally standard samples suggested that patulin and emodin might act as the principal components possessing anti-biofilm and antivirulence activities. This is the first report of (1 the isolation of P. cucumerina from the phyllosphere of O. violaceus and (2 anti-biofilm, antivirulence, and biofilm disruption activities of this fungus. Thus, this study provides fascinating new pathways for screening antipathogenic agents.

  6. The Ciprofloxacin Impact on Biofilm Formation by Proteus Mirabilis and P. Vulgaris Strains

    Science.gov (United States)

    Kwiecinska-Pirog, Joanna; Skowron, Krzysztof; Bartczak, Wojciech; Gospodarek-Komkowska, Eugenia

    2016-01-01

    Background Proteus spp. bacilli belong to opportunistic human pathogens, which are primarily responsible for urinary tract and wound infections. An important virulence factor is their ability to form biofilms that greatly reduce the effectiveness of antibiotics in the site of infection. Objectives The aim of this study was to determine the value of the minimum concentration of ciprofloxacin that eradicates a biofilm of Proteus spp. strains. Materials and Methods A biofilm formation of 20 strains of P. mirabilis and 20 strains of P. vulgaris were evaluated by a spectrophotometric method using 0.1% 2, 3, 5-Triphenyl-tetrazolium chloride solution (TTC, AVANTORTM). On the basis of the results of the absorbance of the formazan, a degree of reduction of biofilm and minimum biofilm eradication (MBE) values of MBE50 and MBE90 were determined. Results All tested strains formed a biofilm. A value of 1.0 μg/mL ciprofloxacin is MBE50 for the strains of both tested species. An MBE90 value of ciprofloxacin for isolates of P. vulgaris was 2 μg/mL and for P. mirabilis was 512 μg/mL. Conclusions Minimum biofilm eradication values of ciprofloxacin obtained in the study are close to the values of the minimal inhibition concentration (MIC). PMID:27303616

  7. Biofilm in endodontics: a review

    OpenAIRE

    Zambrano de la Peña, Sonia; Salcedo-Moncada, Doris; Petkova- Gueorguieva, Marieta; Ventocilla Huasupoma, María

    2017-01-01

    It is demonstrated the efforts made endodontic microbiology and science to get to decipher the secrets of this unique structure although every day new questions arise. We need the treatments we use to combat biofilm achieve oxygenate the periapical ecosystem and basically scrape and loosen the tightly adhering bacteria Knowing the process of biofilm formation, microbial metabolism and strategies that they use to resist and remain hidden but active , we know why we observe refractory periapica...

  8. Critical review on biofilm methods

    DEFF Research Database (Denmark)

    Azeredo, Joana; F. Azevedo, Nuno; Briandet, Romain

    2017-01-01

    Biofilms are widespread in nature and constitute an important strategy implemented by microorganisms to survive in sometimes harsh environmental conditions. They can be beneficial or have a negative impact particularly when formed in industrial settings or on medical devices. As such, research in...... and limitations of several methods. Accordingly, this review aims at helping scientists in finding the most appropriate and up-to-date methods to study their biofilms....

  9. [Effect of Pseudomonas aeruginosa exometabolites on planktonic and biofilm cultures of Escherichia coli].

    Science.gov (United States)

    Kuznetsova, M V; Karpunina, T I; Maslennikova, I L; Nesterova, L Iu; Demakov, V A

    2012-01-01

    Study the effect of P. aeruginosa exometabolites on planktonic and biofilm cultures of bioluminescent E. coli strain. E. coli K12 TG1 (pF1 lux+ Ap(r)) recombinant bioluminescent strain, P. aeruginosa ATCC 27853 reference strain and 2 nosocomial isolates were used. Pyocyanin and pyoverdin content in supernatant of P. aeruginosa over-night cultures was evaluated according to E. Deziel et al. (2001). Planktonic and biofilm cultures of E. coli were obtained in 96-well plates (LB, statically, 37 degrees C), optical density of plankton, film biomass (OD600, OD580) and bioluminescence in plankton and biofilm were evaluated in microplate reader Infiniti M200 (Tecan, Austria). P. aeruginosa exometabolites increased the duration of lag-phase in E. coli, and short term exposition inhibited luminescence of planktonic cells. These effects are determined by bactericidal action ofpyocyanin and pyoverdin. Supernatants ofover-night cultures of P. aeruginosa inhibit formation of biofilm and disrupt the formed biofilm of E. coli. Effect of pyocyanin and pyoverdin on these processes is not established, other factors may have higher significance. Bioluminescence of E. coli K12 TGI that reflects the energetic status of the cell allows to evaluate and prognose the character of coexistence of P. aeruginosa in combined with E. coli planktonic and biofilm culture.

  10. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2015. Scientific Opinion on Flavouring Group Evaluation 99 Revision 1 (FGE.99Rev1): Consideration of furanone derivatives evaluated by the JECFA (63rd, 65th and 69th meetings)

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Nørby, Karin Kristiane

    on metabolism and toxicity. The present consideration concerns a group of six furanone derivatives evaluated by the JECFA at their 63rd, 65th and 69th meetings. This revision of FGE.99 includes the assessment of the 2,5-dimethyl-4-methoxyfuran-3(2H)-one [FL-no: 13.089] cleared for genotoxicity concern compared...

  11. Lactam inhibiting Streptococcus mutans growth on titanium

    Energy Technology Data Exchange (ETDEWEB)

    Xavier, J.G.; Geremias, T.C.; Montero, J.F.D. [Center for Research on Dental Implants (CEPID), School of Dentistry (ODT), Federal University of Santa Catarina - UFSC, Florianópolis/SC, 88040-900 (Brazil); Vahey, B.R. [Herman Ostrow School of Dentistry of USC, 925 W 34 St, Los Angeles, CA 90089 (United States); Benfatti, C.A.M.; Souza, J.C.M.; Magini, R.S. [Center for Research on Dental Implants (CEPID), School of Dentistry (ODT), Federal University of Santa Catarina - UFSC, Florianópolis/SC, 88040-900 (Brazil); Pimenta, A.L., E-mail: andrea@intelab.ufsc.br [Department of Biologia, ERRMECe, Université de Cergy Pontoise, 2, Av. Adolphe Chauvin 95302 Cergy, Pontoise (France); Integrated Laboratories Technologies (InteLab), Dept. Chemical and Food Engineering (EQA), Federal University of Santa Catarina - UFSC, Florianópolis/SC, 88040-970 (Brazil)

    2016-11-01

    The aim of this work was to analyze the activity of novel synthetic lactams on preventing biofilm formation on titanium surfaces. Titanium (Ti6Al4V) samples were exposed to Streptococcus mutans cultures in the presence or absence of a synthetic lactam. After 48 h incubation, planktonic growth was determined by spectrophotometry. Biofilm was evaluated by crystal violet staining and colony forming units (CFU·ml{sup −1}), followed by scanning electron microscopy (SEM). Results showed that the average of adhered viable cells was approximately 1.5 × 10{sup 2} CFU/ml in the presence of lactam and 4 × 10{sup 2} CFU/ml in its absence. This novel compound was considerable active in reducing biofilm formation over titanium surfaces, indicating its potential for the development of antimicrobial drugs targeting the inhibition of the initial stages of bacterial biofilms on dental implants abutments. - Highlights: • A novel synthetic compound is tested on preventing biofilm formation on titanium surfaces • Biofilm inhibition has been achieved on titanium surfaces containing the novel compound. • Planktonic growth of S. mutans was not affected by the presence of lactams on titanium.

  12. Lactam inhibiting Streptococcus mutans growth on titanium

    International Nuclear Information System (INIS)

    Xavier, J.G.; Geremias, T.C.; Montero, J.F.D.; Vahey, B.R.; Benfatti, C.A.M.; Souza, J.C.M.; Magini, R.S.; Pimenta, A.L.

    2016-01-01

    The aim of this work was to analyze the activity of novel synthetic lactams on preventing biofilm formation on titanium surfaces. Titanium (Ti6Al4V) samples were exposed to Streptococcus mutans cultures in the presence or absence of a synthetic lactam. After 48 h incubation, planktonic growth was determined by spectrophotometry. Biofilm was evaluated by crystal violet staining and colony forming units (CFU·ml −1 ), followed by scanning electron microscopy (SEM). Results showed that the average of adhered viable cells was approximately 1.5 × 10 2 CFU/ml in the presence of lactam and 4 × 10 2 CFU/ml in its absence. This novel compound was considerable active in reducing biofilm formation over titanium surfaces, indicating its potential for the development of antimicrobial drugs targeting the inhibition of the initial stages of bacterial biofilms on dental implants abutments. - Highlights: • A novel synthetic compound is tested on preventing biofilm formation on titanium surfaces • Biofilm inhibition has been achieved on titanium surfaces containing the novel compound. • Planktonic growth of S. mutans was not affected by the presence of lactams on titanium.

  13. Plasticity of Candida albicans Biofilms

    Science.gov (United States)

    Daniels, Karla J.

    2016-01-01

    SUMMARY Candida albicans, the most pervasive fungal pathogen that colonizes humans, forms biofilms that are architecturally complex. They consist of a basal yeast cell polylayer and an upper region of hyphae encapsulated in extracellular matrix. However, biofilms formed in vitro vary as a result of the different conditions employed in models, the methods used to assess biofilm formation, strain differences, and, in a most dramatic fashion, the configuration of the mating type locus (MTL). Therefore, integrating data from different studies can lead to problems of interpretation if such variability is not taken into account. Here we review the conditions and factors that cause biofilm variation, with the goal of engendering awareness that more attention must be paid to the strains employed, the methods used to assess biofilm development, every aspect of the model employed, and the configuration of the MTL locus. We end by posing a set of questions that may be asked in comparing the results of different studies and developing protocols for new ones. This review should engender the notion that not all biofilms are created equal. PMID:27250770

  14. Biofilms in the Food Industry: Health Aspects and Control Methods

    Science.gov (United States)

    Galié, Serena; García-Gutiérrez, Coral; Miguélez, Elisa M.; Villar, Claudio J.; Lombó, Felipe

    2018-01-01

    Diverse microorganisms are able to grow on food matrixes and along food industry infrastructures. This growth may give rise to biofilms. This review summarizes, on the one hand, the current knowledge regarding the main bacterial species responsible for initial colonization, maturation and dispersal of food industry biofilms, as well as their associated health issues in dairy products, ready-to-eat foods and other food matrixes. These human pathogens include Bacillus cereus (which secretes toxins that can cause diarrhea and vomiting symptoms), Escherichia coli (which may include enterotoxigenic and even enterohemorrhagic strains), Listeria monocytogenes (a ubiquitous species in soil and water that can lead to abortion in pregnant women and other serious complications in children and the elderly), Salmonella enterica (which, when contaminating a food pipeline biofilm, may induce massive outbreaks and even death in children and elderly), and Staphylococcus aureus (known for its numerous enteric toxins). On the other hand, this review describes the currently available biofilm prevention and disruption methods in food factories, including steel surface modifications (such as nanoparticles with different metal oxides, nanocomposites, antimicrobial polymers, hydrogels or liposomes), cell-signaling inhibition strategies (such as lactic and citric acids), chemical treatments (such as ozone, quaternary ammonium compounds, NaOCl and other sanitizers), enzymatic disruption strategies (such as cellulases, proteases, glycosidases and DNAses), non-thermal plasma treatments, the use of bacteriophages (such as P100), bacteriocins (such us nisin), biosurfactants (such as lichenysin or surfactin) and plant essential oils (such as citral- or carvacrol-containing oils). PMID:29867809

  15. Biofilms in the Food Industry: Health Aspects and Control Methods

    Directory of Open Access Journals (Sweden)

    Serena Galié

    2018-05-01

    Full Text Available Diverse microorganisms are able to grow on food matrixes and along food industry infrastructures. This growth may give rise to biofilms. This review summarizes, on the one hand, the current knowledge regarding the main bacterial species responsible for initial colonization, maturation and dispersal of food industry biofilms, as well as their associated health issues in dairy products, ready-to-eat foods and other food matrixes. These human pathogens include Bacillus cereus (which secretes toxins that can cause diarrhea and vomiting symptoms, Escherichia coli (which may include enterotoxigenic and even enterohemorrhagic strains, Listeria monocytogenes (a ubiquitous species in soil and water that can lead to abortion in pregnant women and other serious complications in children and the elderly, Salmonella enterica (which, when contaminating a food pipeline biofilm, may induce massive outbreaks and even death in children and elderly, and Staphylococcus aureus (known for its numerous enteric toxins. On the other hand, this review describes the currently available biofilm prevention and disruption methods in food factories, including steel surface modifications (such as nanoparticles with different metal oxides, nanocomposites, antimicrobial polymers, hydrogels or liposomes, cell-signaling inhibition strategies (such as lactic and citric acids, chemical treatments (such as ozone, quaternary ammonium compounds, NaOCl and other sanitizers, enzymatic disruption strategies (such as cellulases, proteases, glycosidases and DNAses, non-thermal plasma treatments, the use of bacteriophages (such as P100, bacteriocins (such us nisin, biosurfactants (such as lichenysin or surfactin and plant essential oils (such as citral- or carvacrol-containing oils.

  16. Radiochemical method for evaluating the effect of antibiotics on Escherichia coli biofilms

    International Nuclear Information System (INIS)

    Dix, B.A.; Cohen, P.S.; Laux, D.C.; Cleeland, R.

    1988-01-01

    A simple radiochemical method for evaluating the action of antibiotics on Escherichia coli cells in biofilms is reported. After growth, biofilms of E. coli ATCC 25922 on disks of urinary catheter material were suspended in fresh medium containing or lacking an antibiotic, incubated for 4 h at 37 degrees C, and pulse-labeled with [ 3 H]leucine for 5 min. Radioactivity in trichloracetic acid-precipitable material in the biofilm and in the surrounding medium (planktonic E. coli) was then measured. Antibiotic-induced inhibition of incorporation of [ 3 H]leucine into the cells in the biofilm was far less pronounced than incorporation into planktonic cells and, furthermore, correlated well with loss in viable counts. The method is simple, inexpensive, and extremely timesaving

  17. Soybean Lectin Enhances Biofilm Formation by Bradyrhizobium japonicum in the Absence of Plants

    Directory of Open Access Journals (Sweden)

    Julieta Pérez-Giménez

    2009-01-01

    Full Text Available Soybean lectin (SBL purified from soybean seeds by affinity chromatography strongly bound to Bradyrhizobium japonicum USDA 110 cell surface. This lectin enhanced biofilm formation by B. japonicum in a concentration-dependent manner. Presence of galactose during biofilm formation had different effects in the presence or absence of SBL. Biofilms were completely inhibited in the presence of both SBL and galactose, while in the absence of SBL, galactose was less inhibitory. SBL was very stable, since its agglutinating activity of B. japonicum cells as well as of human group A+ erythrocytes was resistant to preincubation for one week at 60°C. Hence, we propose that plant remnants might constitute a source of this lectin, which might remain active in soil and thus favor B. japonicum biofilm formation in the interval between soybean crop seasons.

  18. Removal and sterilization of biofilms and planktonic bacteria by microwave-induced argon plasma at atmospheric pressure

    International Nuclear Information System (INIS)

    Lee, Mi Hee; Park, Bong Joo; Jin, Soo Chang; Kim, Dohyun; Kim, Jungsung; Park, Jong-Chul; Han, Inho; Hyun, Soon O; Chung, Kie-Hyung

    2009-01-01

    Microbial biofilms are a functional matrix of microbial cells, enveloped in polysaccharides, enzymes and virulence factors secreted by them that can develop on indwelling medical devices and biomaterials. Plasma sterilization has been widely studied in recent years for biological applications. In this study, we evaluated the possibility of removal and anti-recovery of biofilms by microwave-induced argon plasma at atmospheric pressure. We observed that all bacterial biofilms formatted by Gram-negative and Gram-positive bacteria are removed in less than 20 s, and the growth inhibitions of planktonic bacteria within biofilms are also confirmed by plasma exposure for 5 s. These results suggest that our plasma system can be applied to medical and biological fields where the removal of biofilms and their debris is required.

  19. Development of active biofilms of quinoa (Chenopodium quinoa W.) starch containing gold nanoparticles and evaluation of antimicrobial activity.

    Science.gov (United States)

    Pagno, Carlos H; Costa, Tania M H; de Menezes, Eliana W; Benvenutti, Edilson V; Hertz, Plinho F; Matte, Carla R; Tosati, Juliano V; Monteiro, Alcilene R; Rios, Alessandro O; Flôres, Simone H

    2015-04-15

    Active biofilms of quinoa (Chenopodium quinoa, W.) starch were prepared by incorporating gold nanoparticles stabilised by an ionic silsesquioxane that contains the 1,4-diazoniabicyclo[2.2.2]octane chloride group. The biofilms were characterised and their antimicrobial activity was evaluated against Escherichiacoli and Staphylococcusaureus. The presence of gold nanoparticles produces an improvement in the mechanical, optical and morphological properties, maintaining the thermal and barrier properties unchanged when compared to the standard biofilm. The active biofilms exhibited strong antibacterial activity against food-borne pathogens with inhibition percentages of 99% against E. coli and 98% against S. aureus. These quinoa starch biofilms containing gold nanoparticles are very promising to be used as active food packaging for the maintenance of food safety and extension of the shelf life of packaged foods. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Cranberry Flavonoids Modulate Cariogenic Properties of Mixed-Species Biofilm through Exopolysaccharides-Matrix Disruption.

    Directory of Open Access Journals (Sweden)

    Dongyeop Kim

    Full Text Available The exopolysaccharides (EPS produced by Streptococcus mutans-derived glucosyltransferases (Gtfs are essential virulence factors associated with the initiation of cariogenic biofilms. EPS forms the core of the biofilm matrix-scaffold, providing mechanical stability while facilitating the creation of localized acidic microenvironments. Cranberry flavonoids, such as A-type proanthocyanidins (PACs and myricetin, have been shown to inhibit the activity of Gtfs and EPS-mediated bacterial adhesion without killing the organisms. Here, we investigated whether a combination of cranberry flavonoids disrupts EPS accumulation and S. mutans survival using a mixed-species biofilm model under cariogenic conditions. We also assessed the impact of cranberry flavonoids on mechanical stability and the in situ pH at the biofilm-apatite interface. Topical application of an optimized combination of PACs oligomers (100-300 μM with myricetin (2 mM twice daily was used to simulate treatment regimen experienced clinically. Treatments with cranberry flavonoids effectively reduced the insoluble EPS content (>80% reduction vs. vehicle-control; p<0.001, while hindering S. mutans outgrowth within mixed-species biofilms. As a result, the 3D architecture of cranberry-treated biofilms was severely compromised, showing a defective EPS-matrix and failure to develop microcolonies on the saliva-coated hydroxyapatite (sHA surface. Furthermore, topical applications of cranberry flavonoids significantly weaken the mechanical stability of the biofilms; nearly 90% of the biofilm was removed from sHA surface after exposure to a shear stress of 0.449 N/m2 (vs. 36% removal in vehicle-treated biofilms. Importantly, in situ pH measurements in cranberry-treated biofilms showed significantly higher pH values (5.2 ± 0.1 at the biofilm-apatite interface vs. vehicle-treated biofilms (4.6 ± 0.1. Altogether, the data provide important insights on how cranberry flavonoids treatments modulate

  1. Fur is a repressor of biofilm formation in Yersinia pestis.

    Directory of Open Access Journals (Sweden)

    Fengjun Sun

    Full Text Available BACKGROUND: Yersinia pestis synthesizes the attached biofilms in the flea proventriculus, which is important for the transmission of this pathogen by fleas. The hmsHFRS operons is responsible for the synthesis of exopolysaccharide (the major component of biofilm matrix, which is activated by the signaling molecule 3', 5'-cyclic diguanylic acid (c-di-GMP synthesized by the only two diguanylate cyclases HmsT, and YPO0449 (located in a putative operonYPO0450-0448. METHODOLOGY/PRINCIPAL FINDINGS: The phenotypic assays indicated that the transcriptional regulator Fur inhibited the Y. pestis biofilm production in vitro and on nematode. Two distinct Fur box-like sequences were predicted within the promoter-proximal region of hmsT, suggesting that hmsT might be a direct Fur target. The subsequent primer extension, LacZ fusion, electrophoretic mobility shift, and DNase I footprinting assays disclosed that Fur specifically bound to the hmsT promoter-proximal region for repressing the hmsT transcription. In contrast, Fur had no regulatory effect on hmsHFRS and YPO0450-0448 at the transcriptional level. The detection of intracellular c-di-GMP levels revealed that Fur inhibited the c-di-GMP production. CONCLUSIONS/SIGNIFICANCE: Y. pestis Fur inhibits the c-di-GMP production through directly repressing the transcription of hmsT, and thus it acts as a repressor of biofilm formation. Since the relevant genetic contents for fur, hmsT, hmsHFRS, and YPO0450-0448 are extremely conserved between Y. pestis and typical Y. pseudotuberculosis, the above regulatory mechanisms can be applied to Y. pseudotuberculosis.

  2. Inhibitory activity of Iranian plant extracts on growth and biofilm formation by Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Mansouri, S.

    2013-01-01

    Full Text Available Aims: Pseudomonas aeruginosa is a drug resistance opportunistic bacterium. Biofilm formation is key factor for survivalof P. aeruginosa in various environments. Polysaccharides may be involved in biofilm formation. The purpose of thisstudy was to evaluate antimicrobial and anti-biofilm activities of seven plant extracts with known alpha-glucosidaseinhibitory activities on different strains of P. aeruginosa.Methodology and results: Plants were extracted with methanol by the maceration method. Antimicrobial activities weredetermined by agar dilution and by growth yield as measured by OD560nm of the Luria Bertani broth (LB culture with orwithout extracts. In agar dilution method, extracts of Quercus infectoria inhibited the growth of all, while Myrtuscommunis extract inhibited the growth of 3 out of 8 bacterial strains with minimum inhibitory concentration (MIC of 1000μg/mL. All extracts significantly (p≤0.003 reduced growth rate of the bacteria in comparison with the control withoutextracts in LB broth at sub-MIC concentrations (500 μg/mL. All plant extracts significantly (p≤0.003 reduced biofilmformation compared to the controls. Glycyrrhiza glabra and Q. infectoria had the highest anti-biofilm activities. Nocorrelation between the alpha-glucosidase inhibitory activity with growth or the intensity of biofilm formation was found.Conclusion, significance and impact of study: Extracts of Q. infectoria and M. communis had the most antimicrobial,while Q. infectoria and G. glabra had the highest anti-biofilm activities. All plant extracts had anti-biofilm activities withmarginal effect on growth, suggesting that the mechanisms of these activities are unrelated to static or cidal effects.Further work to understand the relation between antimicrobial and biofilm formation is needed for development of newmeans to fight the infectious caused by this bacterium in future.

  3. Toxicity and transformation of graphene oxide and reduced graphene oxide in bacteria biofilm.

    Science.gov (United States)

    Guo, Zhiling; Xie, Changjian; Zhang, Peng; Zhang, Junzhe; Wang, Guohua; He, Xiao; Ma, Yuhui; Zhao, Bin; Zhang, Zhiyong

    2017-02-15

    Impact of graphene based material (GNMs) on bacteria biofilm has not been well understood yet. In this study, we compared the impact of graphene oxide (GO) and reduced graphene oxide (rGO) on biofilm formation and development in Luria-Bertani (LB) medium using Escherichia coli and Staphylococcus aureus as models. GO significantly enhanced the cell growth, biofilm formation, and biofilm development even up to a concentration of 500mg/L. In contrast, rGO (≥50mg/L) strongly inhibited cell growth and biofilm formation. However, the inhibitory effects of rGO (50mg/L and 100mg/L) were attenuated in the mature phase (>24h) and eliminated at 48h. GO at 250mg/L decreased the reactive oxygen species (ROS) levels in biofilm and extracellular region at mature phase. ROS levels were significantly increased by rGO at early phase, while they returned to the same levels as control at mature phase. These results suggest that oxidative stress contributed to the inhibitory effect of rGO on bacterial biofilm. We further found that supplement of extracellular polymeric substances (EPS) in the growth medium attenuated the inhibitory effect of rGO on the growth of developed biofilm. XPS results showed that rGO were oxidized to GO which can enhance the bacterial growth. We deduced that the elimination of the toxicity of rGO at mature phase was contributed by EPS protection and the oxidation of rGO. This study provides new insights into the interaction of GNMs with bacteria biofilm. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Surface conditioning with Escherichia coli cell wall components can reduce biofilm formation by decreasing initial adhesion

    Directory of Open Access Journals (Sweden)

    Luciana C. Gomes

    2017-07-01

    Full Text Available Bacterial adhesion and biofilm formation on food processing surfaces pose major risks to human health. Non-efficient cleaning of equipment surfaces and piping can act as a conditioning layer that affects the development of a new biofilm post-disinfection. We have previously shown that surface conditioning with cell extracts could reduce biofilm formation. In the present work, we hypothesized that E. coli cell wall components could be implicated in this phenomena and therefore mannose, myristic acid and palmitic acid were tested as conditioning agents. To evaluate the effect of surface conditioning and flow topology on biofilm formation, assays were performed in agitated 96-well microtiter plates and in a parallel plate flow chamber (PPFC, both operated at the same average wall shear stress (0.07 Pa as determined by computational fluid dynamics (CFD. It was observed that when the 96-well microtiter plate and the PPFC were used to form biofilms at the same shear stress, similar results were obtained. This shows that the referred hydrodynamic feature may be a good scale-up parameter from high-throughput platforms to larger scale flow cell systems as the PPFC used in this study. Mannose did not have any effect on E. coli biofilm formation, but myristic and palmitic acid inhibited biofilm development by decreasing cell adhesion (in about 50%. These results support the idea that in food processing equipment where biofilm formation is not critical below a certain threshold, bacterial lysis and adsorption of cell components to the surface may reduce biofilm buildup and extend the operational time.

  5. Influence of phosphorus availability on the community structure and physiology of cultured biofilms.

    Science.gov (United States)

    Li, Shuangshuang; Wang, Chun; Qin, Hongjie; Li, Yinxia; Zheng, Jiaoli; Peng, Chengrong; Li, Dunhai

    2016-04-01

    Biofilms have important effects on nutrient cycling in aquatic ecosystems. However, publications about the community structure and functions under laboratory conditions are rare. This study focused on the developmental and physiological properties of cultured biofilms under various phosphorus concentrations performed in a closely controlled continuous flow incubator. The results showed that the biomass (Chl a) and photosynthesis of algae were inhibited under P-limitation conditions, while the phosphatase activity and P assimilation rate were promoted. The algal community structure of biofilms was more likely related to the colonization stage than with the phosphorus availability. Cyanobacteria were more competitive than other algae in biofilms, particularly when cultured under low P levels. A dominance shift occurred from non-filamentous algae in the early stage to filamentous algae in the mid and late stages under P concentrations of 0.01, 0.1 and 0.6 mg/L. However, the total N content, dry weight biomass and bacterial community structure of biofilms were unaffected by phosphorus availability. This may be attributed to the low respiration rate, high accumulation of extracellular polymeric substances and high alkaline phosphatase activity in biofilms when phosphorus availability was low. The bacterial community structure differed over time, while there was little difference between the four treatments, which indicated that it was mainly affected by the colonization stage of the biofilms rather than the phosphorus availability. Altogether, these results suggested that the development of biofilms was influenced by the phosphorus availability and/or the colonization stage and hence determined the role that biofilms play in the overlying water. Copyright © 2015. Published by Elsevier B.V.

  6. The Effect of Cryopreserved Human Placental Tissues on Biofilm Formation of Wound-Associated Pathogens.

    Science.gov (United States)

    Mao, Yong; Singh-Varma, Anya; Hoffman, Tyler; Dhall, Sandeep; Danilkovitch, Alla; Kohn, Joachim

    2018-01-08

    Biofilm, a community of bacteria, is tolerant to antimicrobial agents and ubiquitous in chronic wounds. In a chronic DFU (Diabetic Foot Ulcers) clinical trial, the use of a human cryopreserved viable amniotic membrane (CVAM) resulted in a high rate of wound closure and reduction of wound-related infections. Our previous study demonstrated that CVAM possesses intrinsic antimicrobial activity against a spectrum of wound-associated bacteria under planktonic culture conditions. In this study, we evaluated the effect of CVAM and cryopreserved viable umbilical tissue (CVUT) on biofilm formation of S. aureus and P. aeruginosa , the two most prominent pathogens associated with chronic wounds. Firstly, we showed that, like CVAM, CVUT released antibacterial activity against multiple bacterial pathogens and the devitalization of CVUT reduced its antibacterial activity. The biofilm formation was then measured using a high throughput method and an ex vivo porcine dermal tissue model. We demonstrate that the formation of biofilm was significantly reduced in the presence of CVAM- or CVUT-derived conditioned media compared to control assay medium. The formation of P. aeruginosa biofilm on CVAM-conditioned medium saturated porcine dermal tissues was reduced 97% compared with the biofilm formation on the control medium saturated dermal tissues. The formation of S. auerus biofilm on CVUT-conditioned medium saturated dermal tissues was reduced 72% compared with the biofilm formation on the control tissues. This study is the first to show that human cryopreserved viable placental tissues release factors that inhibit biofilm formation. Our results provide an explanation for the in vivo observation of their ability to support wound healing.

  7. The Effect of Cryopreserved Human Placental Tissues on Biofilm Formation of Wound-Associated Pathogens

    Directory of Open Access Journals (Sweden)

    Yong Mao

    2018-01-01

    Full Text Available Biofilm, a community of bacteria, is tolerant to antimicrobial agents and ubiquitous in chronic wounds. In a chronic DFU (Diabetic Foot Ulcers clinical trial, the use of a human cryopreserved viable amniotic membrane (CVAM resulted in a high rate of wound closure and reduction of wound-related infections. Our previous study demonstrated that CVAM possesses intrinsic antimicrobial activity against a spectrum of wound-associated bacteria under planktonic culture conditions. In this study, we evaluated the effect of CVAM and cryopreserved viable umbilical tissue (CVUT on biofilm formation of S. aureus and P. aeruginosa, the two most prominent pathogens associated with chronic wounds. Firstly, we showed that, like CVAM, CVUT released antibacterial activity against multiple bacterial pathogens and the devitalization of CVUT reduced its antibacterial activity. The biofilm formation was then measured using a high throughput method and an ex vivo porcine dermal tissue model. We demonstrate that the formation of biofilm was significantly reduced in the presence of CVAM- or CVUT-derived conditioned media compared to control assay medium. The formation of P. aeruginosa biofilm on CVAM-conditioned medium saturated porcine dermal tissues was reduced 97% compared with the biofilm formation on the control medium saturated dermal tissues. The formation of S. auerus biofilm on CVUT-conditioned medium saturated dermal tissues was reduced 72% compared with the biofilm formation on the control tissues. This study is the first to show that human cryopreserved viable placental tissues release factors that inhibit biofilm formation. Our results provide an explanation for the in vivo observation of their ability to support wound healing.

  8. Hybrid combinations containing natural products and antimicrobial drugs that interfere with bacterial and fungal biofilms.

    Science.gov (United States)

    Zacchino, Susana A; Butassi, Estefanía; Cordisco, Estefanía; Svetaz, Laura A

    2017-12-15

    Biofilms contribute to the pathogenesis of many chronic and difficult-to eradicate infections whose treatment is complicated due to the intrinsic resistance to conventional antibiotics. As a consequence, there is an urgent need for strategies that can be used for the prevention and treatment of biofilm-associated infections. The combination therapy comprising an antimicrobial drug with a low molecular weight (MW) natural product and an antimicrobial drug (antifungal or antibacterial) appeared as a good alternative to eradicate biofilms. The aims of this review were to perform a literature search on the different natural products that have showed the ability of potentiating the antibiofilm capacity of antimicrobial drugs, to analyze which are the antimicrobial drugs most used in combination, and to have a look on the microbial species most used to prepare biofilms. Seventeen papers, nine on combinations against antifungal biofilms and eight against antibacterial biofilms were collected. Within the text, the following topics have been developed: breaf history of the discovery of biofilms; stages in the development of a biofilm; the most used methodologies to assess antibiofilm-activity; the natural products with capacity of eradicating biofilms when acting alone; the combinations of low MW natural products with antibiotics or antifungal drugs as a strategy for eradicating microbial biofilms and a list of the low MW natural products that potentiate the inhibition capacity of antifungal and antibacterial drugs against biofilms. Regarding combinations against antifungal biofilms, eight over the nine collected works were carried out with in vitro studies while only one was performed with in vivo assays by using Caenorhabditis elegans nematode. All studies use biofilms of the Candida genus. A 67% of the potentiators were monoterpenes and sesquiterpenes and six over the nine works used FCZ as the antifungal drug. The activity of AmpB and Caspo was enhanced in one and two

  9. Inhibition of Cell Differentiation in Bacillus subtilis by Pseudomonas protegens

    Science.gov (United States)

    Powers, Matthew J.; Sanabria-Valentín, Edgardo; Bowers, Albert A.

    2015-01-01

    ABSTRACT Interspecies interactions have been described for numerous bacterial systems, leading to the identification of chemical compounds that impact bacterial physiology and differentiation for processes such as biofilm formation. Here, we identified soil microbes that inhibit biofilm formation and sporulation in the common soil bacterium Bacillus subtilis. We did so by creating a reporter strain that fluoresces when the transcription of a biofilm-specific gene is repressed. Using this reporter in a coculture screen, we identified Pseudomonas putida and Pseudomonas protegens as bacteria that secrete compounds that inhibit biofilm gene expression in B. subtilis. The active compound produced by P. protegens was identified as the antibiotic and antifungal molecule 2,4-diacetylphloroglucinol (DAPG). Colonies of B. subtilis grown adjacent to a DAPG-producing P. protegens strain had altered colony morphologies relative to B. subtilis colonies grown next to a DAPG-null P. protegens strain (phlD strain). Using a subinhibitory concentration of purified DAPG in a pellicle assay, we saw that biofilm-specific gene transcription was delayed relative to transcription in untreated samples. These transcriptional changes also corresponded to phenotypic alterations: both biofilm biomass and spore formation were reduced in B. subtilis liquid cultures treated with subinhibitory concentrations of DAPG. Our results add DAPG to the growing list of antibiotics that impact bacterial development and physiology at subinhibitory concentrations. These findings also demonstrate the utility of using coculture as a means to uncover chemically mediated interspecies interactions between bacteria. IMPORTANCE Biofilms are communities of bacteria adhered to surfaces by an extracellular matrix; such biofilms can have important effects in both clinical and agricultural settings. To identify chemical compounds that inhibited biofilm formation, we used a fluorescent reporter to screen for bacteria that

  10. Ciliates as engineers of phototrophic biofilms

    NARCIS (Netherlands)

    Weerman, Ellen J.; van der Geest, Harm G.; van der Meulen, Myra D.; Manders, Erik M. M.; van de Koppel, Johan; Herman, Peter M. J.; Admiraal, Wim

    1. Phototrophic biofilms consist of a matrix of phototrophs, non-photosynthetic bacteria and extracellular polymeric substances (EPS) which is spatially structured. Despite widespread exploitation of algae and bacteria within phototrophic biofilms, for example by protozoans, the 'engineering'

  11. Current understanding of multi-species biofilms

    DEFF Research Database (Denmark)

    Yang, Liang; Liu, Yang; Wu, Hong

    2011-01-01

    every year worldwide to deal with damage to equipment, contaminations of products, energy losses, and infections in human beings resulted from microbial biofilms. Microorganisms compete, cooperate, and communicate with each other in multi-species biofilms. Understanding the mechanisms of multi......Direct observation of a wide range of natural microorganisms has revealed the fact that the majority of microbes persist as surface-attached communities surrounded by matrix materials, called biofilms. Biofilms can be formed by a single bacterial strain. However, most natural biofilms are actually......-species biofilm formation will facilitate the development of methods for combating bacterial biofilms in clinical, environmental, industrial, and agricultural areas. The most recent advances in the understanding of multi-species biofilms are summarized and discussed in the review....

  12. Killing of Serratia marcescens biofilms with chloramphenicol.

    Science.gov (United States)

    Ray, Christopher; Shenoy, Anukul T; Orihuela, Carlos J; González-Juarbe, Norberto

    2017-03-29

    Serratia marcescens is a Gram-negative bacterium with proven resistance to multiple antibiotics and causative of catheter-associated infections. Bacterial colonization of catheters mainly involves the formation of biofilm. The objectives of this study were to explore the susceptibility of S. marcescens biofilms to high doses of common antibiotics and non-antimicrobial agents. Biofilms formed by a clinical isolate of S. marcescens were treated with ceftriaxone, kanamycin, gentamicin, and chloramphenicol at doses corresponding to 10, 100 and 1000 times their planktonic minimum inhibitory concentration. In addition, biofilms were also treated with chemical compounds such as polysorbate-80 and ursolic acid. S. marcescens demonstrated susceptibility to ceftriaxone, kanamycin, gentamicin, and chloramphenicol in its planktonic form, however, only chloramphenicol reduced both biofilm biomass and biofilm viability. Polysorbate-80 and ursolic acid had minimal to no effect on either planktonic and biofilm grown S. marcescens. Our results suggest that supratherapeutic doses of chloramphenicol can be used effectively against established S. marcescens biofilms.

  13. Candida Biofilms: Development, Architecture, and Resistance

    Science.gov (United States)

    CHANDRA, JYOTSNA; MUKHERJEE, PRANAB K.

    2015-01-01

    Intravascular device–related infections are often associated with biofilms (microbial communities encased within a polysaccharide-rich extracellular matrix) formed by pathogens on the surfaces of these devices. Candida species are the most common fungi isolated from catheter-, denture-, and voice prosthesis–associated infections and also are commonly isolated from contact lens–related infections (e.g., fungal keratitis). These biofilms exhibit decreased susceptibility to most antimicrobial agents, which contributes to the persistence of infection. Recent technological advances have facilitated the development of novel approaches to investigate the formation of biofilms and identify specific markers for biofilms. These studies have provided extensive knowledge of the effect of different variables, including growth time, nutrients, and physiological conditions, on biofilm formation, morphology, and architecture. In this article, we will focus on fungal biofilms (mainly Candida biofilms) and provide an update on the development, architecture, and resistance mechanisms of biofilms. PMID:26350306

  14. [Formation of the Pseudomonas aeruginosa PAO1 biofilms in the presence of hydrogen peroxide; the effect of the AiiA gene].

    Science.gov (United States)

    Pliuta, V A; Andreenko, Iu V; Kuznetsov, A E; Khmel', I A

    2013-01-01

    In the natural ecosystems, most bacteria exist as specifically organized biofilms attached to various surfaces; the biofilms have a complex architecture and are surrounded by an exopolymeric matrix. The bacteria in the biofilms are extremely resistant to antibacterial agents. The ability of the pathogenic bacteria to produce biofilms causes serious problems in medicine. Therefore, the study of the action of different compounds with antibacterial activity is of great interest. In this work, we studied the effect of the hydrogen peroxide (H2O2) on the formation of biofilms by Pseudomonas aeruginosa PAO1. It was shown that H2O2 in concentrations that do not suppress bacterial growth (or suppress it only weakly) stimulates the formation of the biofilms. At higher concentrations, H2O2 inhibits the formation of the biofilms. In order to determine if the stimulation of the biofilm formation depends on Quorum Sensing (QS) regulation, the plasmid pME6863 containing the heterologous gene aiiA encoding the N-acyl-homoserine lactonase AiiA was introduced into P. aeruginosa PAO1. The synthesis by cells of this enzyme degrading N-acyl-homoserine lactones (AHL), signaling molecules of the QS systems, led to the absence of the stimulation of the biofilm formation by the action of H2O2. This fact indicates that the stimulation of the biofilm formation in the presence of H2O2 depends on the functioning of the QS systems of the gene expression regulation of P. aeruginosa PAO1.

  15. POTENSI HAMBAT PERMEN LUNAK SIRIH DAN PINANG TERHADAP PEMBENTUKAN BIOFILM Streptococcus mutans

    Directory of Open Access Journals (Sweden)

    Maryati 1

    2017-12-01

    Full Text Available Betle leaf (Piper betle L. essential oil and catechu nut (Areca catechu L. extracts have been known to be able to inhibit biofilm formation of S. mutans. This research aimed to characterize the chemical compounds of betle leaf esssential oil, screen the phytochemicals in catechu nut ethanol extract, and assess the inhibitory potential of betle and catechu in chewy candy on biofilm formation by S. mutans. The experiment included preparation of extracts and chemical characterization of the raw materials, formulation of chewy candy, measurement of biofilm inhibition, and sensory evaluation of the candy. In vitro examination for inhibitory potency of betle and catechu chewy candy against biofilm formation S. mutans ATCC 31987 was performed in adhesion phase (4 hours and active accumulation phase (18 hours. Antibacterial assay was performed in BHI broth media on microplate 96 wells. Crystal violet 0.5% was used to stain the biofilm and Optical Density (OD was measured at λ 450 nm. The GC-MS analysis detected 32 compounds in the essential oil of betle leaf. The Betle leaf essential oil contained chavicol acetate, isoeugenol, chavibetol acetate, chavicol, and allylcatechol 3.4-diacetate, while catechu nut ethanol extract contained flavonoids and tannins. The components were possibly the inhibitory agents of S. mutans biofilm formation. Chewy candy containing 0.8% betle leaf essential oil and 2.3% catechu nut extract had effective inhibitory potential for S. mutans biofilm formation. Inhibition during adhesion phase was 74.5±0.7%, while that for accumulation phase was 60.8±1.8%. Sensory analysis suggests that the candy was slightly liked by the panelists (5±2.

  16. Cleaning and Disinfection of Bacillus cereus Biofilm.

    Science.gov (United States)

    Deal, Amanda; Klein, Dan; Lopolito, Paul; Schwarz, John Spencer

    2016-01-01

    Methodology has been evolving for the testing of disinfectants against bacterial single-species biofilms, as the difficulty of biofilm remediation continues to gain much-needed attention. Bacterial single-species biofilm contamination presents a real risk to good manufacturing practice-regulated industries. However, mixed-species biofilms and biofilms containing bacterial spores remain an even greater challenge for cleaning and disinfection. Among spore-forming microorganisms frequently encountered in pharmaceutical manufacturing areas, the spores of Bacillus cereus are often determined to be the hardest to disinfect and eradicate. One of the reasons for the low degree of susceptibility to disinfection is the ability of these spores to be encapsulated within an exopolysachharide biofilm matrix. In this series of experiments, we evaluated the disinfectant susceptibility of B. cereus biofilms relative to disassociated B. cereus spores and biofilm from a non-spore-forming species. Further, we assessed the impact that pre-cleaning has on increasing that susceptibility. Methodology has been evolving for the testing of disinfectants against bacterial single-species biofilms, as the difficulty of biofilm remediation continues to gain much-needed attention. Bacterial single-species biofilm contamination presents a real risk to good manufacturing practice-regulated industries. However, mixed-species biofilms and biofilms containing bacterial spores remain an even greater challenge for cleaning and disinfection. Among spore-forming microorganisms frequently encountered in pharmaceutical manufacturing areas, the spores of Bacillus cereus are often determined to be the hardest to disinfect and eradicate. One of the reasons for the low degree of susceptibility to disinfection is the ability of these spores to be encapsulated within an exopolysachharide biofilm matrix. In this series of experiments, we evaluated the disinfectant susceptibility of B. cereus biofilms relative to

  17. Influence of biofilm-forming lactic acid bacteria against methicillin-resistant Staphylococcus aureus (MRSA S547

    Directory of Open Access Journals (Sweden)

    Laavanya M. Kumar

    2017-12-01

    Full Text Available Objective: To investigate the antibacterial effect of selected lactic acid bacteria (LAB biofilms on the planktonic and biofilm population of methicillin-resistant Staphylococcus aureus (MRSA (S547. Methods: In this study, biofilm-forming LAB were isolated from tairu and kefir. Isolate Y1 and isolate KF were selected based on their prominent inhibition against test pathogens (using spot-on-agar method and agar-well-diffusion assay and efficient biofilm production (using tissue culture plate method. They were then identified as Lactobacillus casei (L. casei Y1 and Lactobacillus plantarum (L. plantarum KF, respectively using 16S rDNA gene sequencing. The influence of incubation time, temperature and aeration on the biofilm production of L. casei Y1 and L. plantarum KF was also investigated using tissue culture plate method. The inhibitory activity of both the selected LAB biofilms was evaluated against MRSA (Institute for Medical Research code: S547 using L. plantarum ATCC 8014 as the reference strain. Results: L. casei Y1 showed the highest reduction of MRSA biofilms, by 3.53 log at 48 h while L. plantarum KF records the highest reduction of 2.64 log at 36 h. In inhibiting planktonic population of MRSA (S547, both L. casei Y1 and L. plantarum KF biofilms recorded their maximum reduction of 4.13 log and 3.41 log at 24 h, respectively. Despite their inhibitory effects being time-dependent, both LAB biofilms exhibited good potential in controlling the biofilm and planktonic population of MRSA (S547. Conclusions: The results from this study could highlight the importance of analysing biofilms of LAB to enhance their antibacterial efficacy. Preferably, these protective biofilms of LAB could also be a better alternative to control the formation of biofilms by pathogens such as MRSA. Keywords: MRSA, Biofilms, Lactic acid bacteria, Antibacterial

  18. When the swimming gets tough, the tough form a biofilm.

    Science.gov (United States)

    Belas, Robert

    2013-10-01

    Bacteria live either as independent planktonic cells or as members of surface-attached communities called biofilms. Motility and biofilm development are mutually exclusive events, and control of the phase of this 'swim-or-stick' switch involves the ability of the bacterium to sense and respond appropriately to a surface. Cairns et al. (2013) report that the Bacillus subtilis flagellum functions in surface-sensing. Using mutants of B. subtilis that prevent flagellum rotation, they measured the expression and activity of DegU, the response regulator of the two-component DegS-DegU circuit. DegU activity and degU transcription increased when flagellum rotation was prevented, and were dependent on the DegS kinase. Inhibiting flagellar rotation by overexpressing the EpsE flagellar 'clutch' or addition of anti-flagellin antiserum also increased degU transcription and activity. These results suggest B. subtilis senses restriction of flagellum rotation as the cell nears a surface. Inhibition of the flagellum activates the DegS-DegU circuit to turn on biofilm formation, i.e. the flagellum is acting as a mechanosensor of surfaces. B. subtilis joins an ever-expanding group of bacteria, including species of Vibrio, Proteus and Caulobacter that use the flagellum as a surface sensor. © 2013 John Wiley & Sons Ltd.

  19. Effect of Silver or Copper Nanoparticles-Dispersed Silane Coatings on Biofilm Formation in Cooling Water Systems

    Science.gov (United States)

    Ogawa, Akiko; Kanematsu, Hideyuki; Sano, Katsuhiko; Sakai, Yoshiyuki; Ishida, Kunimitsu; Beech, Iwona B.; Suzuki, Osamu; Tanaka, Toshihiro

    2016-01-01

    Biofouling often occurs in cooling water systems, resulting in the reduction of heat exchange efficiency and corrosion of the cooling pipes, which raises the running costs. Therefore, controlling biofouling is very important. To regulate biofouling, we focus on the formation of biofilm, which is the early step of biofouling. In this study, we investigated whether silver or copper nanoparticles-dispersed silane coatings inhibited biofilm formation in cooling systems. We developed a closed laboratory biofilm reactor as a model of a cooling pipe and used seawater as a model for cooling water. Silver or copper nanoparticles-dispersed silane coating (Ag coating and Cu coating) coupons were soaked in seawater, and the seawater was circulated in the laboratory biofilm reactor for several days to create biofilms. Three-dimensional images of the surface showed that sea-island-like structures were formed on silane coatings and low concentration Cu coating, whereas nothing was formed on high concentration Cu coatings and low concentration Ag coating. The sea-island-like structures were analyzed by Raman spectroscopy to estimate the components of the biofilm. We found that both the Cu coating and Ag coating were effective methods to inhibit biofilm formation in cooling pipes. PMID:28773758

  20. Effect of tannic and gallic acids alone or in combination with carbenicillin or tetracycline on Chromobacterium violaceum CV026 growth, motility, and biofilm formation.

    Science.gov (United States)

    Dusane, Devendra H; O'May, Che; Tufenkji, Nathalie

    2015-07-01

    Chromobacterium violaceum is an opportunistic pathogen that causes infections that are difficult to treat. The goal of this research was to evaluate the effect of selected tannins (tannic acid (TA) and gallic acid (GA)) on bacterial growth, motility, antibiotic (carbenicillin, tetracycline) susceptibility, and biofilm formation. Both tannins, particularly TA, impaired bacterial growth levels and swimming motilities at sub-minimum inhibitory concentrations (sub-MICs). In combination with tannins, antibiotics showed increased MICs, suggesting that tannins interfered with antibacterial activity. Sub-MICs of tetracycline or TA alone enhanced biofilm formation of C. violaceum; however, in combination, these compounds inhibited biofilm formation. In contrast, carbenicillin at sub-MICs was effective in inhibiting C. violaceum biofilm formation; however, in combination with lower concentrations of TA or GA, biofilms were enhanced. These results provide insights into the effects of tannins on C. violaceum growth and their varying interaction with antibiotics used to target C. violaceum infections.

  1. Microbiële biofilms in tandheelkunde

    NARCIS (Netherlands)

    Krom, B.P.

    2015-01-01

    Aangehechte gemeenschappen van micro-organismen, ook wel biofilms genoemd, zijn altijd en overal aanwezig. Hoewel biofilms een slechte naam hebben, zijn ze meestal natuurlijk, gezond en zelfs gewenst. In de tandartspraktijk komen zowel gezonde (orale biofilms) als ongezonde (bijv. in de waterleiding

  2. Microbiële biofilms in tandheelkunde

    NARCIS (Netherlands)

    Krom, B.P.

    2015-01-01

    Aangehechte gemeenschappen van micro-organismen, ook wel biofilms genoemd, zijn altijd en overal aanwezig. Hoewel biofilms een slechte naam hebben, zijn ze meestal natuurlijk, gezond en zelfs gewenst. In de mondzorgpraktijk komen zowel gezonde (orale biofilms) als ongezonde (bijv. in de waterleiding

  3. Differential growth of wrinkled biofilms

    Science.gov (United States)

    Espeso, D. R.; Carpio, A.; Einarsson, B.

    2015-02-01

    Biofilms are antibiotic-resistant bacterial aggregates that grow on moist surfaces and can trigger hospital-acquired infections. They provide a classical example in biology where the dynamics of cellular communities may be observed and studied. Gene expression regulates cell division and differentiation, which affect the biofilm architecture. Mechanical and chemical processes shape the resulting structure. We gain insight into the interplay between cellular and mechanical processes during biofilm development on air-agar interfaces by means of a hybrid model. Cellular behavior is governed by stochastic rules informed by a cascade of concentration fields for nutrients, waste, and autoinducers. Cellular differentiation and death alter the structure and the mechanical properties of the biofilm, which is deformed according to Föppl-Von Kármán equations informed by cellular processes and the interaction with the substratum. Stiffness gradients due to growth and swelling produce wrinkle branching. We are able to reproduce wrinkled structures often formed by biofilms on air-agar interfaces, as well as spatial distributions of differentiated cells commonly observed with B. subtilis.

  4. Dynamics of Biofilm Regrowth in Drinking Water Distribution Systems.

    Science.gov (United States)

    Douterelo, I; Husband, S; Loza, V; Boxall, J

    2016-07-15

    The majority of biomass within water distribution systems is in the form of attached biofilm. This is known to be central to drinking water quality degradation following treatment, yet little understanding of the dynamics of these highly heterogeneous communities exists. This paper presents original information on such dynamics, with findings demonstrating patterns of material accumulation, seasonality, and influential factors. Rigorous flushing operations repeated over a 1-year period on an operational chlorinated system in the United Kingdom are presented here. Intensive monitoring and sampling were undertaken, including time-series turbidity and detailed microbial analysis using 16S rRNA Illumina MiSeq sequencing. The results show that bacterial dynamics were influenced by differences in the supplied water and by the material remaining attached to the pipe wall following flushing. Turbidity, metals, and phosphate were the main factors correlated with the distribution of bacteria in the samples. Coupled with the lack of inhibition of biofilm development due to residual chlorine, this suggests that limiting inorganic nutrients, rather than organic carbon, might be a viable component in treatment strategies to manage biofilms. The research also showed that repeat flushing exerted beneficial selective pressure, giving another reason for flushing being a viable advantageous biofilm management option. This work advances our understanding of microbiological processes in drinking water distribution systems and helps inform strategies to optimize asset performance. This research provides novel information regarding the dynamics of biofilm formation in real drinking water distribution systems made of different materials. This new knowledge on microbiological process in water supply systems can be used to optimize the performance of the distribution network and to guarantee safe and good-quality drinking water to consumers. Copyright © 2016 Douterelo et al.

  5. Antiadherent activity of Schinus terebinthifolius and Croton urucurana extracts on in vitro biofilm formation of Candida albicans and Streptococcus mutans.

    Science.gov (United States)

    Barbieri, Dicler S V; Tonial, Fabiana; Lopez, Patricia V A; Sales Maia, Beatriz H L N; Santos, Germana D; Ribas, Marina O; Glienke, Chirlei; Vicente, Vania A

    2014-09-01

    To evaluate the antiadherent property of crude, methanol and acetate methanol extract fractions from Schinus terebinthifolius and Croton urucurana in hydroalcoholic (HA) and dimethylsulfoxide (DMSO) solvents on in vitro biofilms formed by Streptococcus mutans and Candida albicans strains. The minimal concentration of adherence (MICA) was determined to evaluate the antiadherent potential of extracts on the in vitro biofilm formation. The extracts of plants were subjected to thin layer chromatography (TLC) in order to detect what class of compounds was responsible for the antiadherent activity. Data were estimated by analysis of variance (ANOVA) complemented by Tukey test level of significance set at 5%. Both plants demonstrated inhibition of S. mutans and C. albicans on in vitro biofilm formation. The biofilms of C. albicans were more efficiently inhibited by the S. terebinthifolius fraction of acetate-methanol and methanol in hydroalcoholic solvents (p<0.05). The S. mutans biofilms adherence was best inhibited by the S. terebinthifolius crude extract and its methanolic fraction, both in hydroalcoholic solvent (p<0.05). TLC of crude extracts and fractions of S. terebinthifolius detected the presence of several active compounds, including phenolic compounds, anthraquinones, terpenoids, and alkaloids. C. urucurana extracts confirmed activity for both microorganisms (p<0.05). However, higher concentrations were needed to achieve antiadherent activity, mainly to inhibit in vitro biofilm formation of C. albicans. The antiadherent potential of both plants on in vitro biofilms formed by C. albicans and S. mutans were confirmed, suggesting the importance of studies about these extracts for therapeutic prevention of oral diseases associated with oral biofilms. Copyright © 2014. Published by Elsevier Ltd.

  6. 2-Methoxy-2,4-diphenyl-3(2H)-furanone-labeled gelatin zymography and reverse zymography: a rapid real-time method for quantification of matrix metalloproteinases-2 and -9 and tissue inhibitors of metalloproteinases.

    Science.gov (United States)

    Min, Danqing; Lyons, James Guy; Jia, Junhong; Lo, Lisa; McLennan, Susan V

    2006-02-01

    Measurement of matrix metalloproteinases (MMPs) and their specific tissue inhibitors of metalloproteinases (TIMPs) by the techniques of zymography and reverse zymography provide useful information regarding the status of matrix accumulation or breakdown. This report describes the use of 2-methoxy-2,4-diphenyl-3(2H)-furanone (MDPF), a fluorescent compound which can be used to label gelatin as a substrate for detection of the gelatin degrading MMP-2 and -9 by zymography. In addition, a modification of the zymographic technique by addition of excess MMPs enables the use of the MDPF-labeled gelatin substrate for the identification and quantification of TIMPs by reverse zymography. Both systems are real-time sensitive reliable quantification techniques, easily used for measurement of these MMPs and TIMPs in clinical, biological, and tissue culture samples.

  7. Determination of furaneol (4-hydroxy-2,5-dimethyl-3(2H)-furanone) in some wines from Italian native grapes by Gas-Chromatography-SIM/MASS spectrometry.

    Science.gov (United States)

    Genovese, Alessandro; Piombino, Paola; Lisanti, Maria Tiziana; Moio, Luigi

    2005-06-01

    Gas Chromatography-Mass Spectrometry (GC-MS) analysis by Selective Ion Monitoring (SIM) was applied to quantify 4-Hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF) in both red and white wines obtained from some Italian cultivar of Vitis vinifera. Wines were extracted by liquid-liquid extraction performed with 1,1,2-trichlorotrifluoroethane (Freon 113). The ion m/z 128 was used for quantification while the ion m/z 129 as qualifier. Precision, linearity and accuracy of the method resulted satisfactory. Results showed a significant variation in the concentration of furaneol in wine with grape variety. Generally, HDMF concentrations in white wines were lower than in red wines. Among white wines, Chardonnay resulted characterized by the highest concentration of HDMF. Among red wines the highest concentrations of HDMF were detected in Primitivo and Refosco varieties.

  8. Efek antibakteri dan penghambatan biofilm ekstrak sereh (Cymbopogon nardus L. terhadap bakteri Streptococcus mutans

    Directory of Open Access Journals (Sweden)

    Zwista Yulia Dewi

    2015-12-01

    Antibacterial effect and biofilm inhibition Of Lemongrass extract (Cymbopogon nardus L. against the growth of Streptococcus mutans. Caries prevention can be carried out by several methods. One of them is by controlling the plaque accumulation on the surface of the teeth. Lemongrass (Cymbopogon nardus L is containing certain compound that can inhibit the growth of bacteria and biofilm. The objective of this research is to observe the influence of antibacterial and biofilm inhibition of lemongrass extract against the growth of S. mutans. Subjects were S. mutans bacteria on KHM90 test as much as 6x108 CFU/ml and on biofilm inhibition test as much as 15x108 CFU/ml. Lemongrass was extracted using petroleum ether followed by using 70% ethanol. Antibacterial activity test carried out with KHM90 determination test using microdilution method on microplate flat bottom 96 wells. Bacteria were prepared by making a suspension in NB media and adjusted to McFarland II standard (6x108 CFU/ml. Biofilm inhibition activity test was performed using microdilution method of the biofilm formed on microplate flat flexible PVC U-bottom 96 wells which were stained using 1% of crystal violet. Bacteria were prepared by making a suspension in BHI media and adjusted to McFarland V standard (15 x108 CFU/ml. The result in the form of optical density (OD was read by Bio-rad microplate reader Benchmark at a wavelength of 595 nm. The value of IC50 was determined by probit method using SPSS version 15.The results of this study of measurements on KHM90 test showed that 108,36% w/v is capable of inhibiting the growth of bacteria. Biofilm inhibitory activity showed IC50 lemongrass value was 0,137% w/v. The conclusion of this study is that lemongrass extract has antibacterial effect against bacteria S. mutans showed by KHM90 obtained at concentrations of 0,18% w/v and there is lemongrass extract biofilm inhibitory effect against the bacteria S. mutans indicated by IC50 value 0,137%

  9. Medical biofilms--nanotechnology approaches.

    Science.gov (United States)

    Neethirajan, Suresh; Clond, Morgan A; Vogt, Adam

    2014-10-01

    Biofilms are colonies of bacteria or fungi that adhere to a surface, protected by an extracellular polymer matrix composed of polysaccharides and extracellular DNA. They are highly complex and dynamic multicellular structures that resist traditional means of killing planktonic bacteria. Recent developments in nanotechnology provide novel approaches to preventing and dispersing biofilm infections, which are a leading cause of morbidity and mortality. Medical device infections are responsible for approximately 60% of hospital acquired infections. In the United States, the estimated cost of caring for healthcare-associated infections is approximately between $28 billion and $45 billion per year. In this review, we will discuss our current understanding of biofilm formation and degradation, its relevance to challenges in clinical practice, and new technological developments in nanotechnology that are designed to address these challenges.

  10. Synergistic Interactions in Multispecies Biofilms

    DEFF Research Database (Denmark)

    Ren, Dawei

    The coexistence of hugely diverse microbes in most environments highlights the intricate interactions in microbial communities, which are central to their properties, such as productivity, stability and the resilience to disturbance. Biofilm, in environmental habitats, is such a spatially...... multispecies biofilm models, oral microbial community, also known as “dental plaque” is thoroughly investigated as a focal point to describe the interspecies interactions [1]. However, owing to the lack of a reliable high throughput and quantitative approach for exploring the interplay between multiple...... bacterial species, the study to elucidate the impact of interaction networks on the multispecies biofilms in natural ecosystems, especially in soil, is still at an early stage. The diverse patterns of interactions within the mixed communities as well as the predatorprey relationship between protozoa...

  11. Growing and Analyzing Biofilms in Flow Chambers

    DEFF Research Database (Denmark)

    Tolker-Nielsen, Tim; Sternberg, Claus

    2011-01-01

    This unit describes the setup of flow chamber systems for the study of microbial biofilms, and methods for the analysis of structural biofilm formation. Use of flow chambers allows direct microscopic investigation of biofilm formation. The biofilms in flow chambers develop under hydrodynamic......, and disassembly and cleaning of the system. In addition, embedding and fluorescent in situ hybridization of flow chamber–grown biofilms are addressed. Curr. Protoc. Microbiol. 21:1B.2.1-1B.2.17. © 2011 by John Wiley & Sons, Inc....

  12. Pattern formation in Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Parsek, Matthew R.; Tolker-Nielsen, Tim

    2008-01-01

    Bacteria are capable of forming elaborate multicellular communities called biofilms. Pattern formation in biofilms depends on cell proliferation and cellular migration in response to the available nutrients and other external cues, as well as on self-generated intercellular signal molecules...... and the production of an extracellular matrix that serves as a structural 'scaffolding' for the biofilm cells. Pattern formation in biofilms allows cells to position themselves favorably within nutrient gradients and enables buildup and maintenance of physiologically distinct subpopulations, which facilitates...... survival of one or more subpopulations upon environmental insult, and therefore plays an important role in the innate tolerance displayed by biofilms toward adverse conditions....

  13. Biofilm reactors for ethanol production

    Energy Technology Data Exchange (ETDEWEB)

    Vega, J L; Clausen, E C; Gaddy, J L

    1988-07-01

    Whole cell immobilization has been studied in the laboratory during the last few years as a method to improve the performance and economics of most fermentation processes. Among the various techniques available for cell immobilization, methods that provide generation of a biofilm offer reduced diffusional resistance, high productivities, and simple operation. This paper reviews some of the important aspects of biofilm reactors for ethanol production, including reactor start-up, steady state behavior, process stability, and mathematical modeling. Special emphasis is placed on covalently bonded Saccharomyces cerevisiae in packed bed reactors.

  14. Extracellular DNA Release Acts as an Antifungal Resistance Mechanism in Mature Aspergillus fumigatus Biofilms

    Science.gov (United States)

    Rajendran, Ranjith; Williams, Craig; Lappin, David F.; Millington, Owain; Martins, Margarida

    2013-01-01

    Aspergillus fumigatus has been shown to form biofilms that are associated with adaptive antifungal resistance mechanisms. These include multidrug efflux pumps, heat shock proteins, and extracellular matrix (ECM). ECM is a key structural and protective component of microbial biofilms and in bacteria has been shown to contain extracellular DNA (eDNA). We therefore hypothesized that A. fumigatus biofilms also possess eDNA as part of the ECM, conferring a functional role. Fluorescence microscopy and quantitative PCR analyses demonstrated the presence of eDNA, which was released phase dependently (8 autolysis, were significantly upregulated as the biofilm matured and that inhibition of chitinases affected biofilm growth and stability, indicating mechanistically that autolysis was possibly involved. Finally, using checkerboard assays, it was shown that combinational treatment of biofilms with DNase plus amphotericin B and caspofungin significantly improved antifungal susceptibility. Collectively, these data show that eDNA is an important structural component of A. fumigatus ECM that is released through autolysis, which is important for protection from environmental stresses, including antifungal therapy. PMID:23314962

  15. Apolar Bioactive Fraction of Melipona scutellaris Geopropolis on Streptococcus mutans Biofilm

    Directory of Open Access Journals (Sweden)

    Marcos Guilherme da Cunha

    2013-01-01

    Full Text Available The aim of this study was to evaluate the influence of the bioactive nonpolar fraction of geopropolis on Streptococcus mutans biofilm. The ethanolic extract of Melipona scutellaris geopropolis was subjected to a liquid-liquid partition, thus obtaining the bioactive hexane fraction (HF possessing antimicrobial activity. The effects of HF on S. mutans UA159 biofilms generated on saliva-coated hydroxyapatite discs were analyzed by inhibition of formation, killing assay, and glycolytic pH-drop assays. Furthermore, biofilms treated with vehicle control and HF were analyzed by scanning electron microscopy (SEM. HF at 250 μg/mL and 400 μg/mL caused 38% and 53% reduction in the biomass of biofilm, respectively, when compared to vehicle control (P0.05. In conclusion, the bioactive HF of geopropolis was promising to control the S. mutans biofilm formation, without affecting the microbial population but interfering with its structure by reducing the biochemical content of biofilm matrix.

  16. Resistance and recovery of river biofilms receiving short pulses of Triclosan and Diuron.

    Science.gov (United States)

    Proia, L; Morin, S; Peipoch, M; Romaní, A M; Sabater, S

    2011-08-01

    The effects of the herbicide Diuron (DIU) and the bactericide Triclosan (TCS) were assessed on laboratory-grown stream biofilms. Four week-old biofilms were exposed in mesocosms to 48-hours of short pulses of either DIU or TCS. The direct and indirect effects of each toxicant on the biofilms, and the subsequent recovery of the biofilms, were evaluated according to structural and functional biomarkers. These parameters were analyzed immediately before exposure, immediately after exposure, and 9 and 16days post-exposure. DIU caused an increase in diatom mortality (+79%), which persisted until the end of the experiment. TCS also affected diatom mortality (+41%), although the effect did not appear until 1week post-exposure. TCS caused an increase in bacterial mortality (+45%); however, this parameter returned to normal values 1week post-exposure. TCS compromised the cellular integrity of the green alga Spirogyra sp., whereas DIU did not. TCS also strongly inhibited phosphate uptake (-71%), which did not return to normal values until 2weeks post-exposure. DIU directly affected algae, but barely affected the heterotrophs, whereas TCS seriously impaired bacteria (direct effect) as well as autotrophs (indirect effect). However, the biofilms recovered their normal structure and function within only a few days to a few weeks. These findings demonstrate the capacity of biofilms to cope with periodic inputs of toxicants, but also the risks associated to repeated exposure or multi-contamination in aquatic ecosystems. Copyright © 2011 Elsevier B.V. All rights reserved.

  17. Apolar Bioactive Fraction of Melipona scutellaris Geopropolis on Streptococcus mutans Biofilm.

    Science.gov (United States)

    da Cunha, Marcos Guilherme; Franchin, Marcelo; Galvão, Lívia Câmara de Carvalho; Bueno-Silva, Bruno; Ikegaki, Masaharu; de Alencar, Severino Matias; Rosalen, Pedro Luiz

    2013-01-01

    The aim of this study was to evaluate the influence of the bioactive nonpolar fraction of geopropolis on Streptococcus mutans biofilm. The ethanolic extract of Melipona scutellaris geopropolis was subjected to a liquid-liquid partition, thus obtaining the bioactive hexane fraction (HF) possessing antimicrobial activity. The effects of HF on S. mutans UA159 biofilms generated on saliva-coated hydroxyapatite discs were analyzed by inhibition of formation, killing assay, and glycolytic pH-drop assays. Furthermore, biofilms treated with vehicle control and HF were analyzed by scanning electron microscopy (SEM). HF at 250  μ g/mL and 400  μ g/mL caused 38% and 53% reduction in the biomass of biofilm, respectively, when compared to vehicle control (P 0.05). In conclusion, the bioactive HF of geopropolis was promising to control the S. mutans biofilm formation, without affecting the microbial population but interfering with its structure by reducing the biochemical content of biofilm matrix.

  18. Reducing Staphylococcus aureus biofilm formation on stainless steel 316L using functionalized self-assembled monolayers.

    Science.gov (United States)

    Kruszewski, Kristen M; Nistico, Laura; Longwell, Mark J; Hynes, Matthew J; Maurer, Joshua A; Hall-Stoodley, Luanne; Gawalt, Ellen S

    2013-05-01

    Stainless steel 316L (SS316L) is a common material used in orthopedic implants. Bacterial colonization of the surface and subsequent biofilm development can lead to refractory infection of the implant. Since the greatest risk of infection occurs perioperatively, strategies that reduce bacterial adhesion during this time are important. As a strategy to limit bacterial adhesion and biofilm formation on SS316L, self-assembled monolayers (SAMs) were used to modify the SS316L surface. SAMs with long alkyl chains terminated with hydrophobic (-CH3) or hydrophilic (oligoethylene glycol) tail groups were used to form coatings and in an orthogonal approach, SAMs were used to immobilize gentamicin or vancomycin on SS316L for the first time to form an "active" antimicrobial coating to inhibit early biofilm development. Modified SS316L surfaces were characterized using surface infrared spectroscopy, contact angles, MALDI-TOF mass spectrometry and atomic force microscopy. The ability of SAM-modified SS316L to retard biofilm development by Staphylococcus aureus was functionally tested using confocal scanning laser microscopy with COMSTAT image analysis, scanning electron microscopy and colony forming unit analysis. Neither hydrophobic nor hydrophilic SAMs reduced biofilm development. However, gentamicin-linked and vancomycin-linked SAMs significantly reduced S. aureus biofilm formation for up to 24 and 48 h, respectively. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Cymbopogon citratus essential oil: effect on polymicrobial caries-related biofilm with low cytotoxicity.

    Science.gov (United States)

    Oliveira, Maria Alcionéia Carvalho de; Borges, Aline Chiodi; Brighenti, Fernanda Lourenção; Salvador, Marcos José; Gontijo, Aline Vidal Lacerda; Koga-Ito, Cristiane Yumi

    2017-11-06

    The objective of this study was to evaluate the effects of Cymbopogon citratus essential oil and its main compound (citral) against primary dental colonizers and caries-related species. Chemical characterization of the essential oil was performed by gas chromatography/mass spectroscopy (GC/MS), and the main compound was determined. Antimicrobial activity was tested against Actinomyces naeslundii, Lactobacillus acidophilus, S. gordonii, S. mitis, S. mutans, S. sanguinis and S. sobrinus. Minimum inhibitory and bactericide concentrations were determined by broth microdilution assay for streptococci and lactobacilli reference, and for clinical strains. The effect of the essential oil on bacterial adhesion and biofilm formation/disruption was investigated. Negative (without treatment) and positive controls (chlorhexidine) were used. The effect of citral on preformed biofilm was also tested using the same methodology. Monospecies and microcosm biofilms were tested. ANOVA or Kruskal-Wallis tests were used (α=0.05). Cytotoxicity of the essential oil to human keratinocytes was performed by MTT assay. GC/MS demonstrated one major component (citral). The essential oil showed an inhibitory effect on all tested bacterial species, including S. mutans and L. acidophilus. Essential oil of C. citratus (10X MIC) reduced the number of viable cells of lactobacilli and streptococci biofilms (p essential oil inhibited adhesion of caries-related polymicrobial biofilm to dental enamel (p essential oil showed low cytotoxicity to human keratinocytes. Based on these findings, this study can contribute to the development of new formulations for products like mouthwash, against dental biofilms.

  20. A short history of microbial biofilms and biofilm infections

    DEFF Research Database (Denmark)

    Høiby, Niels

    2017-01-01

    The observation of aggregated microbes surrounded by a self-produced matrix adhering to surfaces or located in tissues or secretions is old since both Leeuwenhoek and Pasteur have described the phenomenon. In environmental and technical microbiology, biofilms, 80–90 years ago, were already shown ...

  1. Biofilm Induced Tolerance Towards Antimicrobial Peptides

    DEFF Research Database (Denmark)

    Folkesson, Anders; Haagensen, Janus Anders Juul; Zampaloni, Claudia

    2008-01-01

    Increased tolerance to antimicrobial agents is thought to be an important feature of microbes growing in biofilms. We address the question of how biofilm organization affects antibiotic susceptibility. We established Escherichia coli biofilms with differential structural organization due...... to the presence of IncF plasmids expressing altered forms of the transfer pili in two different biofilm model systems. The mature biofilms were subsequently treated with two antibiotics with different molecular targets, the peptide antibiotic colistin and the fluoroquinolone ciprofloxacin. The dynamics...... of microbial killing were monitored by viable count determination, and confocal laser microscopy. Strains forming structurally organized biofilms show an increased bacterial survival when challenged with colistin, compared to strains forming unstructured biofilms. The increased survival is due to genetically...

  2. Molecular Basis for Saccharomyces cerevisiae Biofilm Development

    DEFF Research Database (Denmark)

    Andersen, Kaj Scherz

    In this study, I sought to identify genes regulating the global molecular program for development of sessile multicellular communities, also known as biofilm, of the eukaryotic microorganism, Saccharomyces cerevisiae (yeast). Yeast biofilm has a clinical interest, as biofilms can cause chronic...... infections in humans. Biofilm is also interesting from an evolutionary standpoint, as an example of primitive multicellularity. By using a genome-wide screen of yeast deletion mutants, I show that 71 genes are essential for biofilm formation. Two-thirds of these genes are required for transcription of FLO11......, but only a small subset is previously described as regulators of FLO11. These results reveal that the regulation of biofilm formation and FLO11 is even more complex than what has previously been described. I find that the molecular program for biofilm formation shares many essential components with two...

  3. Cell death in Pseudomonas aeruginosa biofilm development

    DEFF Research Database (Denmark)

    Webb, J.S.; Thompson, L.S.; James, S.

    2003-01-01

    Bacteria growing in biofilms often develop multicellular, three-dimensional structures known as microcolonies. Complex differentiation within biofilms of Pseudomonas aeruginosa occurs, leading to the creation of voids inside microcolonies and to the dispersal of cells from within these voids....... However, key developmental processes regulating these events are poorly understood. A normal component of multicellular development is cell death. Here we report that a repeatable pattern of cell death and lysis occurs in biofilms of P. aeruginosa during the normal course of development. Cell death...... occurred with temporal and spatial organization within biofilms, inside microcolonies, when the biofilms were allowed to develop in continuous-culture flow cells. A subpopulation of viable cells was always observed in these regions. During the onset of biofilm killing and during biofilm development...

  4. Modelling the growth of a methanotrophic biofilm

    DEFF Research Database (Denmark)

    Arcangeli, J.-P.; Arvin, E.

    1999-01-01

    This article discusses the growth of methanotrophic biofilms. Several independent biofilm growths scenarios involving different inocula were examined. Biofilm growth, substrate removal and product formation were monitored throughout the experiments. Based on the oxygen consumption it was concluded...... that heterotrophs and nitrifiers co-existed with methanotrophs in the biofilm. Heterotrophic biomass grew on soluble polymers formed by the hydrolysis of dead biomass entrapped in the biofilm. Nitrifier populations developed because of the presence of ammonia in the mineral medium. Based on these experimental...... was performed on this model. It indicated that the most influential parameters were those related to the biofilm (i.e. density; solid-volume fraction; thickness). This suggests that in order to improve the model, further research regarding the biofilm structure and composition is needed....

  5. Biofilms of vaginal Lactobacillus in vitro test.

    Science.gov (United States)

    Wei, Xiao-Yu; Zhang, Rui; Xiao, Bing-Bing; Liao, Qin-Ping

    2017-01-01

    This paper focuses on biofilms of Lactobacillus spp. - a type of normal flora isolated from healthy human vaginas of women of childbearing age; thereupon, it broadens the research scope of investigation of vaginal normal flora. The static slide culture method was adopted to foster biofilms, marked by specific fluorescence staining. Laser scanning confocal and scanning electron microscopy were used to observe the microstructure of the biofilms. Photographs taken from the microstructure were analysed to calculate the density of the biofilms. The body of Lactobacillus spp., though red, turned yellow when interacting with the green extracellular polysaccharides. The structure of the biofilm and aquaporin within the biofilm were imaged. Lactobacillus density increases over time. This study provides convincing evidence that Lactobacillus can form biofilms and grow over time in vitro. This finding establishes an important and necessary condition for selecting proper strains for the pharmaceutics of vaginal ecology.

  6. The clinical impact of bacterial biofilms

    DEFF Research Database (Denmark)

    Høiby, Niels; Ciofu, Oana; Johansen, Helle Krogh

    2011-01-01

    Bacteria survive in nature by forming biofilms on surfaces and probably most, if not all, bacteria (and fungi) are capable of forming biofilms. A biofilm is a structured consortium of bacteria embedded in a self-produced polymer matrix consisting of polysaccharide, protein and extracellular DNA....... Bacterial biofilms are resistant to antibiotics, disinfectant chemicals and to phagocytosis and other components of the innate and adaptive inflammatory defense system of the body. It is known, for example, that persistence of staphylococcal infections related to foreign bodies is due to biofilm formation....... Likewise, chronic Pseudomonas aeruginosa lung infections in cystic fibrosis patients are caused by biofilm growing mucoid strains. Gradients of nutrients and oxygen exist from the top to the bottom of biofilms and the bacterial cells located in nutrient poor areas have decreased metabolic activity...

  7. Current and future trends for biofilm reactors for fermentation processes.

    Science.gov (United States)

    Ercan, Duygu; Demirci, Ali

    2015-03-01

    Biofilms in the environment can both cause detrimental and beneficial effects. However, their use in bioreactors provides many advantages including lesser tendencies to develop membrane fouling and lower required capital costs, their higher biomass density and operation stability, contribution to resistance of microorganisms, etc. Biofilm formation occurs naturally by the attachment of microbial cells to the support without use of any chemicals agent in biofilm reactors. Biofilm reactors have been studied and commercially used for waste water treatment and bench and pilot-scale production of value-added products in the past decades. It is important to understand the fundamentals of biofilm formation, physical and chemical properties of a biofilm matrix to run the biofilm reactor at optimum conditions. This review includes the principles of biofilm formation; properties of a biofilm matrix and their roles in the biofilm formation; factors that improve the biofilm formation, such as support materials; advantages and disadvantages of biofilm reactors; and industrial applications of biofilm reactors.

  8. Live and heat-killed Lactobacillus spp. interfere with Streptococcus mutans and Streptococcus oralis during biofilm development on titanium surface.

    Science.gov (United States)

    Ciandrini, E; Campana, R; Baffone, W

    2017-06-01

    This research investigates the ability of live and heat-killed (HK) Lactic Acid Bacteria (LAB) to interfere with Streptococcus mutans ATCC 25175 and Streptococcus oralis ATCC 9811 during biofilm formation. Eight Lactobacillus spp. and two oral colonizers, pathogenic Streptococcus mutans and resident Streptococcus oralis, were characterized for their aggregation abilities, cell surface properties and biofilm formation ability on titanium surface. Then, the interference activity of selected live and HK Lactobacillus spp. during S. mutans and S. oralis biofilm development were performed. The cell-free culture supernatants (CFCS) anti-biofilm activity was also determined. LAB possess good abilities of auto-aggregation (from 14.19 to 28.97%) and of co-aggregation with S. oralis. The cell-surfaces characteristics were most pronounced in S. mutans and S. oralis, while the highest affinities to xylene and chloroform were observed in Lactobacillus rhamnosus ATCC 53103 (56.37%) and Lactobacillus paracasei B21060 (43.83%). S. mutans and S. oralis developed a biofilm on titanium surface, while LAB showed a limited or no ability to create biofilm. Live and HK L. rhamnosus ATCC 53103 and L. paracasei B21060 inhibited streptococci biofilm formation by competition and displacement mechanisms with no substantial differences. The CFCSs of both LAB strains, particularly the undiluted one of L. paracasei B21060, decreased S. mutans and S. oralis biofilm formation. This study evidenced the association of LAB aggregation abilities and cell-surface properties with the LAB-mediated inhibition of S. mutans and S. oralis biofilm formation. Lactobacilli showed different mechanisms of action and peculiar strain-specific characteristics, maintained also in the heat-killed LAB. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Reducing Staphylococcus aureus biofilm formation on stainless steel 316L using functionalized self-assembled monolayers

    International Nuclear Information System (INIS)

    Kruszewski, Kristen M.; Nistico, Laura; Longwell, Mark J.; Hynes, Matthew J.; Maurer, Joshua A.; Hall-Stoodley, Luanne; Gawalt, Ellen S.

    2013-01-01

    Stainless steel 316L (SS316L) is a common material used in orthopedic implants. Bacterial colonization of the surface and subsequent biofilm development can lead to refractory infection of the implant. Since the greatest risk of infection occurs perioperatively, strategies that reduce bacterial adhesion during this time are important. As a strategy to limit bacterial adhesion and biofilm formation on SS316L, self-assembled monolayers (SAMs) were used to modify the SS316L surface. SAMs with long alkyl chains terminated with hydrophobic (− CH 3 ) or hydrophilic (oligoethylene glycol) tail groups were used to form coatings and in an orthogonal approach, SAMs were used to immobilize gentamicin or vancomycin on SS316L for the first time to form an “active” antimicrobial coating to inhibit early biofilm development. Modified SS316L surfaces were characterized using surface infrared spectroscopy, contact angles, MALDI-TOF mass spectrometry and atomic force microscopy. The ability of SAM-modified SS316L to retard biofilm development by Staphylococcus aureus was functionally tested using confocal scanning laser microscopy with COMSTAT image analysis, scanning electron microscopy and colony forming unit analysis. Neither hydrophobic nor hydrophilic SAMs reduced biofilm development. However, gentamicin-linked and vancomycin-linked SAMs significantly reduced S. aureus biofilm formation for up to 24 and 48 h, respectively. - Highlights: ► SS316L was modified with glycol terminated SAMs in order to reduce biofilm growth. ► Antibiotics gentamicin and vancomycin were immobilized on SS316L via SAMs. ► Only the antibiotic modifications reduced biofilm development on SS316L

  10. Reducing Staphylococcus aureus biofilm formation on stainless steel 316L using functionalized self-assembled monolayers

    Energy Technology Data Exchange (ETDEWEB)

    Kruszewski, Kristen M., E-mail: kruszewskik@duq.edu [Duquesne University, Department of Chemistry and Biochemistry, 600 Forbes Avenue, Pittsburgh, PA 15282 (United States); Nistico, Laura, E-mail: lnistico@wpahs.org [Allegheny General Hospital, Center for Genomic Sciences, Allegheny-Singer Research Institute, 320 East North Avenue, 11th floor, South Tower, Pittsburgh, PA 15212 (United States); Longwell, Mark J., E-mail: mlongwel@wpahs.org [Allegheny General Hospital, Center for Genomic Sciences, Allegheny-Singer Research Institute, 320 East North Avenue, 11th floor, South Tower, Pittsburgh, PA 15212 (United States); Hynes, Matthew J., E-mail: mjhynes@go.wustl.edu [Washington University in St. Louis, Department of Chemistry, One Brookings Drive, St. Louis, MO 63130 (United States); Maurer, Joshua A., E-mail: maurer@wustl.edu [Washington University in St. Louis, Department of Chemistry, One Brookings Drive, St. Louis, MO 63130 (United States); Hall-Stoodley, Luanne, E-mail: L.Hall-Stoodley@soton.ac.uk [Southampton Wellcome Trust Clinical Research Facility/NIHR Respiratory BRU, University of Southampton Faculty of Medicine, Southampton General Hospital, Tremona Road, Southampton, Hampshire SO16 6YD (United Kingdom); Gawalt, Ellen S., E-mail: gawalte@duq.edu [Duquesne University, Department of Chemistry and Biochemistry, McGowan Institute for Regenerative Medicine, 600 Forbes Avenue, Pittsburgh, PA 15282 (United States)

    2013-05-01

    Stainless steel 316L (SS316L) is a common material used in orthopedic implants. Bacterial colonization of the surface and subsequent biofilm development can lead to refractory infection of the implant. Since the greatest risk of infection occurs perioperatively, strategies that reduce bacterial adhesion during this time are important. As a strategy to limit bacterial adhesion and biofilm formation on SS316L, self-assembled monolayers (SAMs) were used to modify the SS316L surface. SAMs with long alkyl chains terminated with hydrophobic (− CH{sub 3}) or hydrophilic (oligoethylene glycol) tail groups were used to form coatings and in an orthogonal approach, SAMs were used to immobilize gentamicin or vancomycin on SS316L for the first time to form an “active” antimicrobial coating to inhibit early biofilm development. Modified SS316L surfaces were characterized using surface infrared spectroscopy, contact angles, MALDI-TOF mass spectrometry and atomic force microscopy. The ability of SAM-modified SS316L to retard biofilm development by Staphylococcus aureus was functionally tested using confocal scanning laser microscopy with COMSTAT image analysis, scanning electron microscopy and colony forming unit analysis. Neither hydrophobic nor hydrophilic SAMs reduced biofilm development. However, gentamicin-linked and vancomycin-linked SAMs significantly reduced S. aureus biofilm formation for up to 24 and 48 h, respectively. - Highlights: ► SS316L was modified with glycol terminated SAMs in order to reduce biofilm growth. ► Antibiotics gentamicin and vancomycin were immobilized on SS316L via SAMs. ► Only the antibiotic modifications reduced biofilm development on SS316L.

  11. Early staphylococcal biofilm formation on solid orthopaedic implant materials: in vitro study.

    Directory of Open Access Journals (Sweden)

    Hironobu Koseki

    Full Text Available Biofilms forming on the surface of biomaterials can cause intractable implant-related infections. Bacterial adherence and early biofilm formation are influenced by the type of biomaterial used and the physical characteristics of implant surface. In this in vitro research, we evaluated the ability of Staphylococcus epidermidis, the main pathogen in implant-related infections, to form biofilms on the surface of the solid orthopaedic biomaterials, oxidized zirconium-niobium alloy, cobalt-chromium-molybdenum alloy (Co-Cr-Mo, titanium alloy (Ti-6Al-4V, commercially pure titanium (cp-Ti and stainless steel. A bacterial suspension of Staphylococcus epidermidis strain RP62A (ATCC35984 was added to the surface of specimens and incubated. The stained biofilms were imaged with a digital optical microscope and the biofilm coverage rate (BCR was calculated. The total amount of biofilm was determined with the crystal violet assay and the number of viable cells in the biofilm was counted using the plate count method. The BCR of all the biomaterials rose in proportion to culture duration. After culturing for 2-4 hours, the BCR was similar for all materials. However, after culturing for 6 hours, the BCR for Co-Cr-Mo alloy was significantly lower than for Ti-6Al-4V, cp-Ti and stainless steel (P0.05. These results suggest that surface properties, such as hydrophobicity or the low surface free energy of Co-Cr-Mo, may have some influence in inhibiting or delaying the two-dimensional expansion of biofilm on surfaces with a similar degree of smoothness.

  12. In vitro Effects of Lemongrass Extract on Candida albicans Biofilms, Human Cells Viability, and Denture Surface.

    Science.gov (United States)

    Madeira, Petrus L B; Carvalho, Letícia T; Paschoal, Marco A B; de Sousa, Eduardo M; Moffa, Eduardo B; da Silva, Marcos A Dos Santos; Tavarez, Rudys de Jesus Rodolfo; Gonçalves, Letícia M

    2016-01-01

    The purpose of this study was to investigate whether immersion of a denture surface in lemongrass extract (LGE) has effects on C. albicans biofilms, human cell viability and denture surface. Minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) were performed for LGE against C. albicans. For biofilm analysis, discs were fabricated using a denture acrylic resin with surface roughness standardization. C. albicans biofilms were developed on saliva-coated discs, and the effects of LGE at MIC, 5XMIC, and 10XMIC were investigated during biofilm formation and after biofilm maturation. Biofilms were investigated for cell counting, metabolic activity, and microscopic analysis. The cytotoxicity of different concentrations of LGE to peripheral blood mononuclear cells (PBMC) was analyzed using MTT. The effects of LGE on acrylic resin were verified by measuring changes in roughness, color and flexural strength after 28 days of immersion. Data were analyzed by ANOVA, followed by a Tukey test at a 5% significance level. The minimal concentration of LGE required to inhibit C. albicans growth was 0.625 mg/mL, while MFC was 2.5 mg/mL. The presence of LGE during biofilm development resulted in a reduction of cell counting (p 0.05). There were no verified differences in color perception, roughness, or flexural strength after immersion in LGE at MIC compared to the control (p > 0.05). It could be concluded that immersion of the denture surface in LGE was effective in reducing C. albicans biofilms with no deleterious effects on acrylic properties at MIC. MIC was also an effective and safe concentration for use.

  13. Thiazolidinedione-8 alters symbiotic relationship in C. albicans-S. mutans dual species biofilm

    Directory of Open Access Journals (Sweden)

    Mark eFeldman

    2016-02-01

    Full Text Available The small molecule, thiazolidinedione-8 (S-8 was shown to impair biofilm formation of various microbial pathogens, including the fungus Candida albicans and Streptococcus mutans. Previously, we have evaluated the specific molecular mode of S-8 action against C. albicans biofilm-associated pathogenicity. In this study we investigated the influence of S-8 on dual species, C. albicans-S. mutans biofilm. We show that in the presence of S-8 a reduction of the co-species biofilm formation occurred with a major effect on C. albicans. Biofilm biomass and exopolysaccharide (EPS production were significantly reduced by S-8. Moreover, the agent caused oxidative stress associated with a strong induction of reactive oxygen species (ROS and hydrogen peroxide uptake inhibition by a mixed biofilm. In addition, S-8 altered symbiotic relationship between these species by a complex mechanism. Streptococcal genes associated with quorum sensing (comDE and luxS, EPS production (gtfBCD and gbpB, as well as genes related to protection against oxidative stress (nox and sodA were markedly upregulated by S-8. In contrast, fungal genes related to hyphae formation (hwp1, adhesion (als3, hydrophobicity (csh1 and oxidative stress response (sod1, sod2 and cat1 were downregulated in the presence of S-8. In addition, ywp1 gene associated with yeast form of C. albicans was induced by S-8, which is correlated with appearance of mostly yeast cells in S-8 treated dual species biofilms. We concluded that S-8 disturbs symbiotic balance between C. albicans and S. mutans in dual species biofilm.

  14. Antifungal effects of undecylenic acid on the biofilm formation of Candida albicans.

    Science.gov (United States)

    Shi, Dongmei; Zhao, Yaxin; Yan, Hongxia; Fu, Hongjun; Shen, Yongnian; Lu, Guixia; Mei, Huan; Qiu, Ying; Li, Dongmei; Liu, Weida

    2016-05-01

    Undecylenic acid can effectively control skin fungal infection, but the mechanism of its fungal inhibition is unclear. Hyphal growth of Candida albicans (C. albicans) and biofilm formation have been well recognized as important virulence factors for the initiation of skin infection and late development of disseminated infection. In this study, we seek to investigate antifungal mechanisms of undecylenic acid by evaluating the virulence factors of C. albicans during biofilm formation. We found that undecylenic acid inhibits biofilm formation of C. albicans effectively with optimal concentration above 3 mM. In the presence of this compound, the morphological transition from yeast to filamentous phase is abolished ultimately when the concentration of undecylenic acid is above 4 mM. Meanwhile, the cell surface is crumpled, and cells display an atrophic appearance under scanning electron microscopy even with low concentration of drug treatment. On the other hand, the drug treatment decreases the transcriptions of hydrolytic enzymes such as secreted aspartic protease, lipase, and phospholipase. Hyphal formation related genes, like HWP1, are significantly reduced in transcriptional level in drug-treated biofilm condition as well. The down-regulated profile of these genes leads to a poorly organized biofilm in undecylenic acid treated environment.

  15. CdTe–TiO2 nanocomposite: an impeder of bacterial growth and biofilm

    International Nuclear Information System (INIS)

    Gholap, Haribhau; Yadav, Prasad; Ogale, Satishchandra; Patil, Rajendra; Gade, Wasudeo; Banpurkar, Arun

    2013-01-01

    The resurgence of infectious diseases and associated issues related to antibiotic resistance has raised enormous challenges which may possibly be confronted primarily by nanotechnology routes. One key need of critical significance in this context is the development of an agent capable of inhibiting quorum sensing mediated biofilm formation in pathogenic organisms. In this work we examine the possible use of a nanocomposite, CdTe–TiO 2 , as an impeder of growth and biofilm. In the presence of CdTe–TiO 2 , scanning electron microscopy (SEM) analysis shows exposed cells without the surrounding matrix. Confocal laser scanning microscopy shows spatially distributed fluorescence, a typical indication of an impeded biofilm, as opposed to the control which shows matrix-covered cells and continuous fluorescence, typical of biofilm formation. Quantitatively, the inhibition of biofilm was ∼57%. CdTe–TiO 2 also exhibits good antibacterial properties against Gram positive and Gram negative organisms by virtue of the generation of reactive oxygen species inside the cells, reflected by a ruptured appearance in the SEM analysis. (paper)

  16. Beta- Lactam Antibiotics Stimulate Biofilm Formation in Non-Typeable Haemophilus influenzae by Up-Regulating Carbohydrate Metabolism

    Science.gov (United States)

    Wu, Siva; Li, Xiaojin; Gunawardana, Manjula; Maguire, Kathleen; Guerrero-Given, Debbie; Schaudinn, Christoph; Wang, Charles; Baum, Marc M.; Webster, Paul

    2014-01-01

    Non-typeable Haemophilus influenzae (NTHi) is a common acute otitis media pathogen, with an incidence that is increased by previous antibiotic treatment. NTHi is also an emerging causative agent of other chronic infections in humans, some linked to morbidity, and all of which impose substantial treatment costs. In this study we explore the possibility that antibiotic exposure may stimulate biofilm formation by NTHi bacteria. We discovered that sub-inhibitory concentrations of beta-lactam antibiotic (i.e., amounts that partially inhibit bacterial growth) stimulated the biofilm-forming ability of NTHi strains, an effect that was strain and antibiotic dependent. When exposed to sub-inhibitory concentrations of beta-lactam antibiotics NTHi strains produced tightly packed biofilms with decreased numbers of culturable bacteria but increased biomass. The ratio of protein per unit weight of biofilm decreased as a result of antibiotic exposure. Antibiotic-stimulated biofilms had altered ultrastructure, and genes involved in glycogen production and transporter function were up regulated in response to antibiotic exposure. Down-regulated genes were linked to multiple metabolic processes but not those involved in stress response. Antibiotic-stimulated biofilm bacteria were more resistant to a lethal dose (10 µg/mL) of cefuroxime. Our results suggest that beta-lactam antibiotic exposure may act as a signaling molecule that promotes transformation into the biofilm phenotype. Loss of viable bacteria, increase in biofilm biomass and decreased protein production coupled with a concomitant up-regulation of genes involved with glycogen production might result in a biofilm of sessile, metabolically inactive bacteria sustained by stored glycogen. These biofilms may protect surviving bacteria from subsequent antibiotic challenges, and act as a reservoir of viable bacteria once antibiotic exposure has ended. PMID:25007395

  17. Anode biofilm transcriptomics reveals outer surface components essential for high density current production in Geobacter sulfurreducens fuel cells.

    Directory of Open Access Journals (Sweden)

    Kelly P Nevin

    Full Text Available The mechanisms by which Geobacter sulfurreducens transfers electrons through relatively thick (>50 microm biofilms to electrodes acting as a sole electron acceptor were investigated. Biofilms of Geobacter sulfurreducens were grown either in flow-through systems with graphite anodes as the electron acceptor or on the same graphite surface, but with fumarate as the sole electron acceptor. Fumarate-grown biofilms were not immediately capable of significant current production, suggesting substantial physiological differences from current-producing biofilms. Microarray analysis revealed 13 genes in current-harvesting biofilms that had significantly higher transcript levels. The greatest increases were for pilA, the gene immediately downstream of pilA, and the genes for two outer c-type membrane cytochromes, OmcB and OmcZ. Down-regulated genes included the genes for the outer-memb