WorldWideScience

Sample records for bacterial surface colonization

  1. Slowdown of surface diffusion during early stages of bacterial colonization

    Science.gov (United States)

    Vourc'h, T.; Peerhossaini, H.; Léopoldès, J.; Méjean, A.; Chauvat, F.; Cassier-Chauvat, C.

    2018-03-01

    We study the surface diffusion of the model cyanobacterium Synechocystis sp. PCC6803 during the incipient stages of cell contact with a glass surface in the dilute regime. We observe a twitching motility with alternating immobile tumble and mobile run periods, resulting in a normal diffusion described by a continuous-time random walk with a coefficient of diffusion D . Surprisingly, D is found to decrease with time down to a plateau. This is observed only when the cyanobacterial cells are able to produce released extracellular polysaccharides, as shown by a comparative study between the wild-type strain and various polysaccharides-depleted mutants. The analysis of the trajectories taken by the bacterial cells shows that the temporal characteristics of their intermittent motion depend on the instantaneous fraction of visited sites during diffusion. This describes quantitatively the time dependence of D , related to the progressive surface coverage by the polysaccharides. The observed slowdown of the surface diffusion may constitute a basic precursor mechanism for microcolony formation and provides clues for controlling biofilm formation.

  2. Bacterial filamentation accelerates colonization of adhesive spots embedded in biopassive surfaces

    International Nuclear Information System (INIS)

    Möller, Jens; Emge, Philippe; Vizcarra, Ima Avalos; Kollmannsberger, Philip; Vogel, Viola

    2013-01-01

    Sessile bacteria adhere to engineered surfaces and host tissues and pose a substantial clinical and economical risk when growing into biofilms. Most engineered and biological interfaces are of chemically heterogeneous nature and provide adhesive islands for bacterial attachment and growth. To mimic either defects in a surface coating of biomedical implants or heterogeneities within mucosal layers (Peyer's patches), we embedded micrometre-sized adhesive islands in a poly(ethylene glycol) biopassive background. We show experimentally and computationally that filamentation of Escherichia coli can significantly accelerate the bacterial surface colonization under physiological flow conditions. Filamentation can thus provide an advantage to a bacterial population to bridge non-adhesive distances exceeding 5 μm. Bacterial filamentation, caused by blocking of bacterial division, is common among bacterial species and can be triggered by environmental conditions or antibiotic treatment. While great awareness exists that the build-up of antibiotic resistance serves as intrinsic survival strategy, we show here that antibiotic treatment can actually promote surface colonization by triggering filamentation, which in turn prevents daughter cells from being washed away. Our combined microfabrication and computational approaches provide quantitative insights into mechanisms that enable biofouling of biopassive surfaces with embedded adhesive spots, even for spot distances that are multiples of the bacterial length. (paper)

  3. Bacterial filamentation accelerates colonization of adhesive spots embedded in biopassive surfaces

    Science.gov (United States)

    Möller, Jens; Emge, Philippe; Avalos Vizcarra, Ima; Kollmannsberger, Philip; Vogel, Viola

    2013-12-01

    Sessile bacteria adhere to engineered surfaces and host tissues and pose a substantial clinical and economical risk when growing into biofilms. Most engineered and biological interfaces are of chemically heterogeneous nature and provide adhesive islands for bacterial attachment and growth. To mimic either defects in a surface coating of biomedical implants or heterogeneities within mucosal layers (Peyer's patches), we embedded micrometre-sized adhesive islands in a poly(ethylene glycol) biopassive background. We show experimentally and computationally that filamentation of Escherichia coli can significantly accelerate the bacterial surface colonization under physiological flow conditions. Filamentation can thus provide an advantage to a bacterial population to bridge non-adhesive distances exceeding 5 μm. Bacterial filamentation, caused by blocking of bacterial division, is common among bacterial species and can be triggered by environmental conditions or antibiotic treatment. While great awareness exists that the build-up of antibiotic resistance serves as intrinsic survival strategy, we show here that antibiotic treatment can actually promote surface colonization by triggering filamentation, which in turn prevents daughter cells from being washed away. Our combined microfabrication and computational approaches provide quantitative insights into mechanisms that enable biofouling of biopassive surfaces with embedded adhesive spots, even for spot distances that are multiples of the bacterial length.

  4. Bacterial colonization of metallic surfaces exposed in marine environment. Use of bacterial lipids

    International Nuclear Information System (INIS)

    Guezennec, Jean

    1986-01-01

    Addressing fouling and more particularly biofouling phenomena occurring notably on structures in marine environment, this research thesis first describes the fouling phenomenon (components, sequences of biofouling development, bio-film chemical composition). The author reports the study of the composition of the biological veil (microbiological methods, presentation of the different components), addresses the various types of lipids (bacterial markers and others). Then, after a presentation of the experimental equipment and methods (test cells, sample preparation, gas phase chromatography, hydrogenation and bromination, mass spectrometry), the author discusses the influence of different parameters such as the substrate type, speed, season, chlorination, and correlation with thermal transfer [fr

  5. Bacterial colonization of zirconia ceramic surfaces: an in vitro and in vivo study.

    Science.gov (United States)

    Rimondini, Lia; Cerroni, Loredana; Carrassi, Antonio; Torricelli, Paola

    2002-01-01

    The microbial colonization of new ceramic materials developed for abutment manufacturing was assessed. The materials used in these experiments were disks of 'as-fired' and 'rectified' ceramic material made of tetragonal zirconia polycrystals stabilized with yttrium (Y-TZP) and commercially pure grade 2 titanium (Ti) with corresponding eluates. They were tested in vitro with the following bacteria: Streptococcus mutans, S. sanguis, Actinomyces viscosus, A. naeslundii, and Porphyromonas gingivalis. Proliferation was evaluated on plates by inhibitory halos around pits, previously inoculated with eluates obtained from the materials. Bacterial adhesion on materials was quantified by spectrophotometric evaluation of the slime production by the same bacteria. Moreover, early bacterial adhesion was evaluated in human volunteers and observed with SEM. No inhibition of bacterial proliferation using eluates was observed. In vitro as-fired and rectified Y-TZP showed significantly more adherent S. mutans than did Ti disks, while S. sanguis seemed to adhere easily to Ti specimens. No differences were noted for Actinomyces spp and P. gingivalis. In vivo Y-TZP accumulated fewer bacteria than Ti in terms of the total number of bacteria and presence of potential putative pathogens such as rods. No differences were observed between rectified and as-fired Y-TZP. Overall, Y-TZP accumulates fewer bacteria than Ti. Y-TZP may be considered as a promising material for abutment manufacturing.

  6. Bacterial colonization of resin composite cements: influence of material composition and surface roughness.

    Science.gov (United States)

    Glauser, Stephanie; Astasov-Frauenhoffer, Monika; Müller, Johannes A; Fischer, Jens; Waltimo, Tuomas; Rohr, Nadja

    2017-08-01

    So-called secondary caries may develop in the cement gap between the tooth and the bonded restoration. Cement materials with a low susceptibility to biofilm formation are therefore desirable. In the present study, the adhesion of Strepococcus mutans onto three adhesive (Multilink Automix, RelyX Ultimate, and Panavia V5) and three self-adhesive (Multilink Speed Cem, RelyX Unicem 2 Automix, and Panavia SA plus) resin composite cements was evaluated. Previous studies have failed to evaluate concomitantly the effect of both the composition of the cements and their surface roughness on biofilm formation. The presence of S. mutans on cement surfaces with differing degrees of roughness was therefore recorded using fluorescence microscopy and crystal violet staining, and the composition of the cements was analyzed using energy-dispersive X-ray spectroscopy mapping. Biofilm formation on resin composite cements was found to be higher on rougher surfaces, implying that adequate polishing of the cement gap is essential. The use of copper-containing cements (Multilink Automix, Panavia V5, and Panavia SA plus) significantly reduced biofilm formation. © 2017 Eur J Oral Sci.

  7. Elevator buttons as unrecognized sources of bacterial colonization in hospitals.

    Science.gov (United States)

    Kandel, Christopher E; Simor, Andrew E; Redelmeier, Donald A

    2014-01-01

    Elevators are ubiquitous and active inside hospitals, potentially facilitating bacterial transmission. The objective of this study was to estimate the prevalence of bacterial colonization on elevator buttons in large urban teaching hospitals. A total of 120 elevator buttons and 96 toilet surfaces were swabbed over separate intervals at 3 tertiary care hospitals on weekdays and weekends in Toronto, Ontario. For the elevators, swabs were taken from 2 interior buttons (buttons for the ground floor and one randomly selected upper-level floor) and 2 exterior buttons (the "up" button from the ground floor and the "down" button from the upper-level floor). For the toilet surfaces, swabs were taken from the exterior and interior handles of the entry door, the privacy latch, and the toilet flusher. Samples were obtained using standard bacterial collection techniques, followed by plating, culture, and species identification by a technician blind to sample source. The prevalence of colonization of elevator buttons was 61% (95% confidence interval 52%-70%). No significant differences in colonization prevalence were apparent in relation to location of the buttons, day of the week, or panel position within the elevator. Coagulase-negative staphylococci were the most common organisms cultured, whereas Enterococcus and Pseudomonas species were infrequent. Elevator buttons had a higher prevalence of colonization than toilet surfaces (61% v. 43%, p = 0.008). Hospital elevator buttons were commonly colonized by bacteria, although most pathogens were not clinically relevant. The risk of pathogen transmission might be reduced by simple countermeasures.

  8. Bacterial surface adaptation

    Science.gov (United States)

    Utada, Andrew

    2014-03-01

    Biofilms are structured multi-cellular communities that are fundamental to the biology and ecology of bacteria. Parasitic bacterial biofilms can cause lethal infections and biofouling, but commensal bacterial biofilms, such as those found in the gut, can break down otherwise indigestible plant polysaccharides and allow us to enjoy vegetables. The first step in biofilm formation, adaptation to life on a surface, requires a working knowledge of low Reynolds number fluid physics, and the coordination of biochemical signaling, polysaccharide production, and molecular motility motors. These crucial early stages of biofilm formation are at present poorly understood. By adapting methods from soft matter physics, we dissect bacterial social behavior at the single cell level for several prototypical bacterial species, including Pseudomonas aeruginosa and Vibrio cholerae.

  9. Childhood asthma after bacterial colonization of the airway in neonates

    DEFF Research Database (Denmark)

    Bisgaard, Hans; Hermansen, Mette Northman; Buchvald, Frederik

    2007-01-01

    Pathological features of the airway in young children with severe recurrent wheeze suggest an association between bacterial colonization and the initiating events of early asthma. We conducted a study to investigate a possible association between bacterial colonization of the hypopharynx in asymp...

  10. Childhood asthma after bacterial colonization of the airway in neonates

    DEFF Research Database (Denmark)

    Bisgaard, H.; Hermansen, M.N.; Buchvald, F.

    2007-01-01

    Pathological features of the airway in young children with severe recurrent wheeze suggest an association between bacterial colonization and the initiating events of early asthma. We conducted a study to investigate a possible association between bacterial colonization of the hypopharynx in asymp...... in asymptomatic neonates and later development of recurrent wheeze, asthma, and allergy during the first 5 years of life....

  11. Bacterial colonization and gut development in preterm neonates

    DEFF Research Database (Denmark)

    Cilieborg, Malene S.; Boye, Mette; Sangild, Per Torp

    2012-01-01

    Necrotizing enterocolitis (NEC) develops in 5–10% of preterm infants in association with enteral feeding and bacterial colonization. It remains unclear how diet and bacteria interact to protect or provoke the immature gastrointestinal tract. Understanding the factors that control bacterial...... colonization may provide the clue to prevent NEC, and studies in infants must be combined with animal models to understand the mechanisms of the microbiota–epithelium interactions. Analyses of infant fecal samples show that the density and distribution of bacterial species are highly variable......, such as mother's colostrum or milk, that help the immature intestinal immune system to respond appropriately to the highly variable bacterial colonization....

  12. Bacterial Colonization and the Development of Intestinal Defences

    Directory of Open Access Journals (Sweden)

    Hai Ning Shi

    2004-01-01

    Full Text Available In humans, intestinal defences develop during gestation and, at full term, have the capacity to respond in an appropriate manner to infectious agents and foreign antigens. Before an active protective response can occur, however, the gut must first be exposed to colonizing bacteria. Colonization with diverse intestinal microbes is necessary for the development of important gut defenses such as the synthesis and secretion of polymeric immunoglobulin A and the generation of a balanced T helper (Th cell response. Insights into normal immune physiological development of the gut have been made by studying the germ-free animal and intestinal defenses. These studies have provided insights into the physiology of immune responses. Two important immunological functions are the secretion of polymeric immunoglobulin A to protect the intestinal surface against harmful stimuli and inhibition of the systemic response to commensal bacteria and food proteins (eg, oral tolerance to prevent chronic inflammation. Neither function exists in the germ-free state, but rapidly develops after conventionalization (colonization of the germ-free animal. In the present review, the importance of bacterial colonization on the appearance of normal mucosal immune function and to the clinical consequences of inadequate colonization to the development of disease will be discussed. For example, excessive Th2 activity can lead to atopy, whereas Th1 predominance is found in conditions such as Helicobacter pylori gastritis and Crohn's disease. With the eradication of infectious diseases in developed countries in the past three decades, the incidence of atopic and autoimmune diseases has increased. This epidemiological observation has been explained by the 'hygiene hypothesis', which suggests that a reduction in microbial burden by public health measures has contributed to an immunological imbalance in the intestine. A family of pattern recognition receptors (Toll-like receptors on gut

  13. Identification of bacteriology and risk factor analysis of asymptomatic bacterial colonization in pacemaker replacement patients.

    Directory of Open Access Journals (Sweden)

    Xian-Ming Chu

    Full Text Available Recent researches revealed that asymptomatic bacterial colonization on PMs might be ubiquitous and increase the risk of clinical PM infection. Early diagnosis of patients with asymptomatic bacterial colonization could provide opportunity for targeted preventive measures.The present study explores the incidence of bacterial colonization of generator pockets in pacemaker replacement patients without signs of infection, and to analyze risk factors for asymptomatic bacterial colonization.From June 2011 to December 2013, 118 patients underwent pacemaker replacement or upgrade. Identification of bacteria was carried out by bacterial culture and 16S rRNA sequencing. Clinical risk characteristics were analyzed.The total bacterial positive rate was 37.3% (44 cases, and the coagulase-negative Staphylococcus aureus detection rate was the highest. Twenty two (18.6% patients had positive bacterial culture results, of which 50% had coagulase-negative staphylococcus. The bacterial DNA detection rate was 36.4 % (43 cases. Positive bacterial DNA results from pocket tissues and the surface of the devices were 22.0% and 29.7%, respectively. During follow-up (median, 27.0 months, three patients (6.8%, 3/44 became symptomatic with the same genus of microorganism, S. aureus (n=2 and S. epidermidis (n=1. Multivariable logistic regression analysis showed that history of bacterial infection, use of antibiotics, application of antiplatelet drugs, replacement frequency were independent risk factors for asymptomatic bacterial colonization.There was a high incidence of asymptomatic bacterial colonization in pacemaker patients with independent risk factors. Bacterial culture combined genetic testing could improve the detection rate.

  14. Genome-wide identification of bacterial plant colonization genes

    Science.gov (United States)

    Waters, Robert J.; Wetmore, Kelly M.; Mucyn, Tatiana S.; Ryan, Elizabeth M.; Wang, Gaoyan; Ul-Hasan, Sabah; McDonald, Meredith; Yoshikuni, Yasuo; Malmstrom, Rex R.; Deutschbauer, Adam M.; Dangl, Jeffery L.; Visel, Axel

    2017-01-01

    Diverse soil-resident bacteria can contribute to plant growth and health, but the molecular mechanisms enabling them to effectively colonize their plant hosts remain poorly understood. We used randomly barcoded transposon mutagenesis sequencing (RB-TnSeq) in Pseudomonas simiae, a model root-colonizing bacterium, to establish a genome-wide map of bacterial genes required for colonization of the Arabidopsis thaliana root system. We identified 115 genes (2% of all P. simiae genes) with functions that are required for maximal competitive colonization of the root system. Among the genes we identified were some with obvious colonization-related roles in motility and carbon metabolism, as well as 44 other genes that had no or vague functional predictions. Independent validation assays of individual genes confirmed colonization functions for 20 of 22 (91%) cases tested. To further characterize genes identified by our screen, we compared the functional contributions of P. simiae genes to growth in 90 distinct in vitro conditions by RB-TnSeq, highlighting specific metabolic functions associated with root colonization genes. Our analysis of bacterial genes by sequence-driven saturation mutagenesis revealed a genome-wide map of the genetic determinants of plant root colonization and offers a starting point for targeted improvement of the colonization capabilities of plant-beneficial microbes. PMID:28938018

  15. Do edible oils reduce bacterial colonization of enamel in situ?

    Science.gov (United States)

    Hannig, Christian; Kirsch, Jasmin; Al-Ahmad, Ali; Kensche, Anna; Hannig, Matthias; Kümmerer, Klaus

    2013-03-01

    Edible oils are an empiric approach for the prevention of oral diseases. The present in situ study investigated the effect of edible oils on initial bacterial colonization of enamel surfaces. Initial biofilm formation was performed on enamel specimens mounted on maxillary splints and carried by eight subjects. After 1 min of pellicle formation, rinses with safflower oil, olive oil and linseed oil were performed for 10 min. Application of chlorhexidine for 1 min served as positive control. Afterwards, the slabs were carried for 8 h overnight. Samples carried for 8 h without any rinse served as negative controls. The amount of adherent bacteria was determined by DAPI staining (4',6-diamidino-2-phenylindole) and live-dead staining (BacLight). Additionally, determination of colony forming units was performed after desorption of the bacteria. TEM evaluation was carried out after application of the rinses. The number of adherent bacteria on control samples was 6.1 ± 8.1 × 10(5)/cm(2) after 8 h (DAPI). Fluorescence microscopic data from DAPI staining and live-dead staining as well as from the determination of CFU revealed no significant effects of rinsing with oils on the amount of adherent bacteria compared to the non-rinsed control samples. However, with chlorhexidine a significant reduction in the number of bacteria by more than 85 % was achieved (DAPI, chlorhexidine: 8.2 ± 17.1 × 10(4)/cm(2)). The ratio of viable to dead bacteria was almost equal (1:1) irrespective of the rinse adopted as recorded with BacLight. TEM indicated accumulation of oil micelles at the pellicle's surface and modification of its ultrastructure. Rinses with edible oils have no significant impact on the initial pattern and amount of bacterial colonization on enamel over 8 h. Rinses with edible oils cannot be recommended for efficient reduction of oral biofilm formation.

  16. Bacterial colonization and succession in a newly opened hospital.

    Science.gov (United States)

    Lax, Simon; Sangwan, Naseer; Smith, Daniel; Larsen, Peter; Handley, Kim M; Richardson, Miles; Guyton, Kristina; Krezalek, Monika; Shogan, Benjamin D; Defazio, Jennifer; Flemming, Irma; Shakhsheer, Baddr; Weber, Stephen; Landon, Emily; Garcia-Houchins, Sylvia; Siegel, Jeffrey; Alverdy, John; Knight, Rob; Stephens, Brent; Gilbert, Jack A

    2017-05-24

    The microorganisms that inhabit hospitals may influence patient recovery and outcome, although the complexity and diversity of these bacterial communities can confound our ability to focus on potential pathogens in isolation. To develop a community-level understanding of how microorganisms colonize and move through the hospital environment, we characterized the bacterial dynamics among hospital surfaces, patients, and staff over the course of 1 year as a new hospital became operational. The bacteria in patient rooms, particularly on bedrails, consistently resembled the skin microbiota of the patient occupying the room. Bacterial communities on patients and room surfaces became increasingly similar over the course of a patient's stay. Temporal correlations in community structure demonstrated that patients initially acquired room-associated taxa that predated their stay but that their own microbial signatures began to influence the room community structure over time. The α- and β-diversity of patient skin samples were only weakly or nonsignificantly associated with clinical factors such as chemotherapy, antibiotic usage, and surgical recovery, and no factor except for ambulatory status affected microbial similarity between the microbiotas of a patient and their room. Metagenomic analyses revealed that genes conferring antimicrobial resistance were consistently more abundant on room surfaces than on the skin of the patients inhabiting those rooms. In addition, persistent unique genotypes of Staphylococcus and Propionibacterium were identified. Dynamic Bayesian network analysis suggested that hospital staff were more likely to be a source of bacteria on the skin of patients than the reverse but that there were no universal patterns of transmission across patient rooms. Copyright © 2017, American Association for the Advancement of Science.

  17. Effects of bacterial colonization on the porcine intestinal proteome

    DEFF Research Database (Denmark)

    Danielsen, Marianne; Hornshøj, Henrik; Siggers, Richard Harvey

    2007-01-01

    comparison of 12 animals. Our results showed that bacterial colonization differentially affected mechanisms such as proteolysis, epithelial proliferation, and lipid metabolism, which is in good agreement with previous studies of other germ-free animal models. We have also found that E. coli has a profound...... effect on actin remodeling and intestinal proliferation, which may be related to stimulated migration and turnover of enterocytes. Regulations related to L. fermentum colonization involved individual markers for immunoregulatory mechanisms...

  18. Bacterial Endophyte Colonization and Distribution within Plants

    Directory of Open Access Journals (Sweden)

    Shyam L. Kandel

    2017-11-01

    Full Text Available The plant endosphere contains a diverse group of microbial communities. There is general consensus that these microbial communities make significant contributions to plant health. Both recently adopted genomic approaches and classical microbiology techniques continue to develop the science of plant-microbe interactions. Endophytes are microbial symbionts residing within the plant for the majority of their life cycle without any detrimental impact to the host plant. The use of these natural symbionts offers an opportunity to maximize crop productivity while reducing the environmental impacts of agriculture. Endophytes promote plant growth through nitrogen fixation, phytohormone production, nutrient acquisition, and by conferring tolerance to abiotic and biotic stresses. Colonization by endophytes is crucial for providing these benefits to the host plant. Endophytic colonization refers to the entry, growth and multiplication of endophyte populations within the host plant. Lately, plant microbiome research has gained considerable attention but the mechanism allowing plants to recruit endophytes is largely unknown. This review summarizes currently available knowledge about endophytic colonization by bacteria in various plant species, and specifically discusses the colonization of maize plants by Populus endophytes.

  19. Particle surface area and bacterial activity in recirculating aquaculture systems

    DEFF Research Database (Denmark)

    Pedersen, Per Bovbjerg; von Ahnen, Mathis; Fernandes, Paulo

    2017-01-01

    Suspended particles in recirculating aquaculture systems (RAS) provide surface area that can be colonized by bacteria. More particles accumulate as the intensity of recirculation increases thus potentially increasing the bacterial carrying capacity of the systems. Applying a recent, rapid, cultur...... for determining bacterial activity might provide a means for future monitoring and assessment of microbial water quality in aquaculture farming systems......Suspended particles in recirculating aquaculture systems (RAS) provide surface area that can be colonized by bacteria. More particles accumulate as the intensity of recirculation increases thus potentially increasing the bacterial carrying capacity of the systems. Applying a recent, rapid, culture......-independent fluorometric detection method (Bactiquant®) for measuring bacterial activity, the current study explored the relationship between total particle surface area (TSA, derived from the size distribution of particles >5 μm) and bacterial activity in freshwater RAS operated at increasing intensity of recirculation...

  20. Bacterial colonization of colonic crypt mucous gel and disease activity in ulcerative colitis.

    LENUS (Irish Health Repository)

    Rowan, Fiachra

    2012-02-01

    OBJECTIVE: To optimize total bacterial 16S rRNA quantification in microdissected colonic crypts in healthy controls and patients with ulcerative colitis (UC) and to characterize the findings with disease activity. BACKGROUND: Microscopic and molecular techniques have recently converged to allow bacterial enumeration in remote anatomic locations [eg, crypt-associated mucous gel (CAMG)]. The aims of this study were to combine laser capture microdissection (LCM) and 16S rRNA-based quantitative polymerase chain reaction (qPCR) to determine total bacterial copy number in CAMG both in health and in UC and to characterize the findings with disease activity. METHODS: LCM was used to microdissect CAMG from colonic mucosal biopsies from controls (n = 20) and patients with acute (n = 10) or subacute (n = 10) UC. Pan-bacterial 16S rRNA copy number per millimeter square in samples from 6 locations across the large bowel was obtained by qPCR using Desulfovibrio desulfuricans as a reference strain. Copy numbers were correlated with the UC disease activity index (UCDAI) and the simple clinical colitis activity index (SCCAI). RESULTS: Bacterial colonization of CAMG was detectable in all groups. Copy numbers were significantly reduced in acute UC. In subacute colitis, there was a positive correlation between copy number and UCDAI and SCCAI in the ascending, transverse and sigmoid colon. CONCLUSIONS: This study describes a sensitive method of quantitatively assessing bacterial colonization of the colonic CAMG. A positive correlation was found between CAMG bacterial load and subacute disease activity in UC, whereas detectable bacterial load was reduced in acute UC.

  1. Abundance, size distribution and bacterial colonization of transparent exopolymeric particles (TEP) during spring in the Kattegat

    DEFF Research Database (Denmark)

    Mari, X.; Kiørboe, Thomas

    1996-01-01

    The abundance, size distribution and bacterial colonization of transparent exopolymeric particles (TEP) were monitored in the Kattegat (Denmark) at weekly intervals throughout the spring (February-May) encompassing the spring diatom bloom. These recently discovered particles are believed to be fo......The abundance, size distribution and bacterial colonization of transparent exopolymeric particles (TEP) were monitored in the Kattegat (Denmark) at weekly intervals throughout the spring (February-May) encompassing the spring diatom bloom. These recently discovered particles are believed...... of beta differed significantly from three, probably because TEP are fractal. All TEP were colonized by bacteria, and bacteria were both attached to the surface of and embedded in TEP. Yet the number of attached bacteria per TEP was related neither to the surface area nor the volume, but rather scaled...

  2. The quest for a unified view of bacterial land colonization.

    Science.gov (United States)

    Wu, Hao; Fang, Yongjun; Yu, Jun; Zhang, Zhang

    2014-07-01

    Exploring molecular mechanisms underlying bacterial water-to-land transition represents a critical start toward a better understanding of the functioning and stability of the terrestrial ecosystems. Here, we perform comprehensive analyses based on a large variety of bacteria by integrating taxonomic, phylogenetic and metagenomic data, in the quest for a unified view that elucidates genomic, evolutionary and ecological dynamics of the marine progenitors in adapting to nonaquatic environments. We hypothesize that bacterial land colonization is dominated by a single-gene sweep, that is, the emergence of dnaE2 derived from an early duplication event of the primordial dnaE, followed by a series of niche-specific genomic adaptations, including GC content increase, intensive horizontal gene transfer and constant genome expansion. In addition, early bacterial radiation may be stimulated by an explosion of land-borne hosts (for example, plants and animals) after initial land colonization events.

  3. Bacterial colonization of the freshwater planktonic diatom Fragilaria crotonensis

    Czech Academy of Sciences Publication Activity Database

    Znachor, Petr; Šimek, Karel; Nedoma, Jiří

    2012-01-01

    Roč. 66, č. 1 (2012), s. 87-94 ISSN 0948-3055 R&D Projects: GA ČR(CZ) GA206/08/0015; GA ČR(CZ) GAP504/11/2177; GA ČR(CZ) GAP504/11/2182 Institutional research plan: CEZ:AV0Z60170517 Keywords : PDMPO * bacterial colonization * diatoms * Fragilaria crotonensis * flood * reservoir Subject RIV: DA - Hydrology ; Limnology Impact factor: 2.037, year: 2012

  4. Nasal bacterial colonization in cases of idiopathic epistaxis in children.

    Science.gov (United States)

    Kamble, Payal; Saxena, Sonal; Kumar, Sunil

    2015-11-01

    To evaluate the role of nasal bacterial colonization in cases of idiopathic epistaxis in children. A descriptive, hospital based, observational study in our hospital was conducted on total 112 pediatric patients in the age group 4-16 years. Group A (control): 56 patients with no epistaxis; Group B (epistaxis): 56 patients with idiopathic epistaxis. A swab for microbiological evaluation was taken from the anterior nasal cavity of each child. A highly significant association between nasal colonization with pathological Staphylococcus aureus and idiopathic epistaxis was found. The presence of pathological S. aureus colonization in the anterior nasal cavity was also associated with statistically significant number of crusting and presence of dilated blood vessels on the anterior nasal septum of children in epistaxis group. Nasal bacterial colonization with S. aureus leads to a sequence of pathological events i.e. low grade inflammation, crusting and new vessel formation. This leads to irritation in nasal cavity resulting in digital trauma and subsequently epistaxis and thus it plays an important role in causing idiopathic epistaxis in children. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  5. Endogenous Antimicrobial Peptide Expression in Response to Bacterial Epidermal Colonization

    Directory of Open Access Journals (Sweden)

    Michael Brandwein

    2017-11-01

    Full Text Available Bacterial commensal colonization of human skin is vital for the training and maintenance of the skin’s innate and adaptive immune functions. In addition to its physical barrier against pathogen colonization, the skin expresses a variety of antimicrobial peptides (AMPs which are expressed constitutively and induced in response to pathogenic microbial stimuli. These AMPs are differentially effective against a suite of microbial skin colonizers, including both bacterial and fungal residents of the skin. We review the breadth of microorganism-induced cutaneous AMP expression studies and their complementary findings on the efficacy of skin AMPs against different bacterial and fungal species. We suggest further directions for skin AMP research based on emerging skin microbiome knowledge in an effort to advance our understanding of the nuanced host–microbe balance on human skin. Such advances should enable the scientific community to bridge the gap between descriptive disease-state AMP studies and experimental single-species in vitro studies, thereby enabling research endeavors that more closely mimic the natural skin environs.

  6. Bacterial colonization during de novo plaque formation.

    Science.gov (United States)

    Ramberg, Per; Sekino, Satoshi; Uzel, Naciye Guzin; Socransky, Sigmund; Lindhe, Jan

    2003-11-01

    To determine microbial changes that occur during plaque formation in a dentition free of gingival inflammation. Ten subjects were recruited. The study included one preparatory period (2 weeks) and a plaque accumulation period (4 days). The volunteers exercised proper tooth cleaning methods, were scaled and received repeated professional mechanical tooth cleaning during the preparatory period. During the plaque accumulation period, the participants abstained from plaque control measures. Plaque was scored on the approximal surfaces of maxillary and mandibular premolars on Days 0, 1, 2 and 4 using a scale from 0 to 5 and according to the criteria of the Quigley and Hein Plaque Index (QHI). Supragingival plaque samples were obtained from the same intervals and surfaces and evaluated using a checkerboard DNA-DNA hybridization technique. The mean QHI increased from 0 to 1.6 (Day 4). The total number of organisms on Day 0 averaged 140 x 10(5) and increased to about 210 x 10(5) after 4 days without oral hygiene. The most dominant species on Day 0 were members of the genus Actinomyces. These organisms comprised almost 50% of the microbiota evaluated. None of the Actinomyces species increased significantly during the 4 days. Some Streptococcus species increased significantly over time as well as species of the genera Capnocytophaga, Campylobacter, Fusobacteria and Actinomyces actinomycetemcomitans. In the present investigation, the preparatory phase established a situation with minimal gingival inflammation and close to zero amounts of dental plaque. The Day 0 plaque samples exhibited high proportions of Actinomyces species. During the 4 days of no oral hygiene, there was a small increase in total numbers of organisms as well as a modest increase in the proportion of "disease-associated" taxa such as species of the "orange complex" species.

  7. A flow chamber assay for quantitative evaluation of bacterial surface colonization used to investigate the influence of temperature and surface hydrophilicity on the biofilm forming capacity of uropathogenic Escherichia coli

    DEFF Research Database (Denmark)

    Andersen, Thomas Emil; Kingshott, Peter; Palarasah, Yaseelan

    2010-01-01

    very differently. In addition, the temperature was found to have a considerable influence upon the adhesion and biofilm forming capacity of some of the isolates, and that the influence of surface chemistry depended on temperature. Our results suggest that the step from using E. coli laboratory strains...... to clinical isolates entails a significant rise in complexity and yields results that cannot be generalized. The results should be valuable information for researchers working with pre-clinical evaluation of device-associated E. coli infections....... to those found on an implanted device. We have used the method to evaluate the biofilm forming capacity of clinically isolated Escherichia coli on silicone rubber and on silicone rubber containing a hydrophilic coating. It was found that the surface chemistry influenced the colonization of the isolates...

  8. Effect of surface modification of siliconeon Staphylococcus epidermidis adhesion and colonization.

    Science.gov (United States)

    Tang, Haiying; Cao, Ting; Wang, Anfeng; Liang, Xuemei; Salley, Steven O; McAllister, James P; Ng, K Y Simon

    2007-03-15

    Cerebrospinal fluid (CSF) shunts for the treatment of hydrocephalus are generally made of silicone rubber. The growth of bacterial colonies on the silicone surface leads to frequent CSF shunt complications. A systematic study of the effect of the surface modification of silicone on Staphylococcus epidermidis adhesion and colonization was performed for different incubation times by means of colony counting and scanning electron microscopy (SEM). Silicone was modified with different biopolymers and silanes, including heparin, hyaluronan, octadecyltrichlorosilane (OTS), and fluoroalkylsilane (FAS) to provide a stable and biocompatible surface with different surface functional groups and degrees of hydrophobicity. The modified silicone surfaces were studied by using contact angle measurements, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). After 4 and 8 h of incubation, the FAS- and OTS-coated silicone and the hyaluronan coated OTS/silicone surfaces showed significantly reduced bacterial adhesion and colonization compared to blank silicone by both quantification methods. However, the heparin coated OTS/silicone showed significantly increased bacterial adhesion. These results indicate that the nature of the surface functional group and surface roughness determine the extent of bacterial adhesion and colonization. However, the degree of hydrophobicity of the surface did not appear to play a determining role in bacterial adhesion and colonization.

  9. Ecological role of a seaweed secondary metabolite for a colonizing bacterial community.

    Science.gov (United States)

    Persson, Frank; Svensson, Robin; Nylund, Goran M; Fredriksson, N Johan; Pavia, Henrik; Hermansson, Malte

    2011-07-01

    Bacteria associated with seaweeds can both harm and benefit their hosts. Many seaweed species are known to produce compounds that inhibit growth of bacterial isolates, but the ecological role of seaweed metabolites for the associated bacterial community structure is not well understood. In this study the response of a colonizing bacterial community to the secondary metabolite (1,1,3,3-tetrabromo-2-heptanone) from the red alga Bonnemaisonia hamifera was investigated by using field panels coated with the metabolite at a range of concentrations covering those measured at the algal surface. The seaweed metabolite has previously been shown to have antibacterial effects. The metabolite significantly affected the natural fouling community by (i) altering the composition, (ii) altering the diversity by increasing the evenness and (iii) decreasing the density, as measured by terminal restriction fragment length polymorphism in conjunction with clone libraries of the 16S rRNA genes and by bacterial enumeration. No single major bacterial taxon (phylum, class) was particularly affected by the metabolite. Instead changes in community composition were observed at a more detailed phylogenetic level. This indicates a broad specificity of the seaweed metabolite against bacterial colonization, which is supported by the observation that the bacterial density was significantly affected at a lower concentration (0.02 μg cm⁻²) than the composition (1-2.5 μg cm⁻²) and the evenness (5 μg cm⁻²) of the bacterial communities. Altogether, the results emphasize the role of secondary metabolites for control of the density and structure of seaweed-associated bacterial communities.

  10. Polistes olivaceous decreases biotic surface colonization

    African Journals Online (AJOL)

    PRECIOUS

    2009-12-15

    Dec 15, 2009 ... Polistes olivaceous on oral biotic surface (biofilm) model by means of pH response, population of oral bacteria and enamel .... Another 50 subjects used oral rinses of 0.9% normal saline to serve as a negative control and ... Bacterial count of S. mutans, S. sanguis and S. salivarus in each flow. Bacteria.

  11. Candida albicans colonization of surface-sealed interim soft liners.

    Science.gov (United States)

    Olan-Rodriguez, L; Minah, G E; Driscoll, C F

    2000-12-01

    This in-vivo investigation evaluated the effect of 2 denture sealer agents on the microbial colonization of a newly placed soft interim denture liner during a period of 14 days. An interim soft denture liner (Coe-Soft; GC America, Alsip, IL) was coated with 2 different denture surface sealants (Palaseal [Heraeus Kulzer, Irvine, CA] and Mono-Poly [Plastodent, New York, NY]). Three rectangular wells of 1 cm wide x 2 cm long x 2 mm deep were placed in the intaglio of 10 maxillary complete dentures and filled with the soft liner material. The soft liner surface was treated with Palaseal (first well) and Mono-Poly (second well), and the unsealed (third well) was used as a control. These were exposed to the oral cavity for 14 days. The effect the sealant had in the prevention of Candidal colonization in vivo of the soft liner material was evaluated. Microbiological specimens were recovered from all samples and cultivated. Microbiological data from the control and 2-test samples in each denture were tabulated, and statistical analyses were performed. This investigation showed clear differences (p denture liner with either Palaseal or Mono-Poly significantly decreased yeast and bacterial colonization. . Copyright 2000 by The American College of Prosthodontists.

  12. Patterns of gut bacterial colonization in three primate species.

    Science.gov (United States)

    McKenney, Erin A; Rodrigo, Allen; Yoder, Anne D

    2015-01-01

    Host fitness is impacted by trillions of bacteria in the gastrointestinal tract that facilitate development and are inextricably tied to life history. During development, microbial colonization primes the gut metabolism and physiology, thereby setting the stage for adult nutrition and health. However, the ecological rules governing microbial succession are poorly understood. In this study, we examined the relationship between host lineage, captive diet, and life stage and gut microbiota characteristics in three primate species (infraorder, Lemuriformes). Fecal samples were collected from captive lemur mothers and their infants, from birth to weaning. Microbial DNA was extracted and the v4 region of 16S rDNA was sequenced on the Illumina platform using protocols from the Earth Microbiome Project. Here, we show that colonization proceeds along different successional trajectories in developing infants from species with differing dietary regimes and ecological profiles: frugivorous (fruit-eating) Varecia variegata, generalist Lemur catta, and folivorous (leaf-eating) Propithecus coquereli. Our analyses reveal community membership and succession patterns consistent with previous studies of human infants, suggesting that lemurs may serve as a useful model of microbial ecology in the primate gut. Each lemur species exhibits distinct species-specific bacterial diversity signatures correlating to life stages and life history traits, implying that gut microbial community assembly primes developing infants at species-specific rates for their respective adult feeding strategies.

  13. Patterns of gut bacterial colonization in three primate species.

    Directory of Open Access Journals (Sweden)

    Erin A McKenney

    Full Text Available Host fitness is impacted by trillions of bacteria in the gastrointestinal tract that facilitate development and are inextricably tied to life history. During development, microbial colonization primes the gut metabolism and physiology, thereby setting the stage for adult nutrition and health. However, the ecological rules governing microbial succession are poorly understood. In this study, we examined the relationship between host lineage, captive diet, and life stage and gut microbiota characteristics in three primate species (infraorder, Lemuriformes. Fecal samples were collected from captive lemur mothers and their infants, from birth to weaning. Microbial DNA was extracted and the v4 region of 16S rDNA was sequenced on the Illumina platform using protocols from the Earth Microbiome Project. Here, we show that colonization proceeds along different successional trajectories in developing infants from species with differing dietary regimes and ecological profiles: frugivorous (fruit-eating Varecia variegata, generalist Lemur catta, and folivorous (leaf-eating Propithecus coquereli. Our analyses reveal community membership and succession patterns consistent with previous studies of human infants, suggesting that lemurs may serve as a useful model of microbial ecology in the primate gut. Each lemur species exhibits distinct species-specific bacterial diversity signatures correlating to life stages and life history traits, implying that gut microbial community assembly primes developing infants at species-specific rates for their respective adult feeding strategies.

  14. Bacterial translocation in rats nonfunctioning diverted distal colon.

    Science.gov (United States)

    Pinto, Francisco Edilson Leite; Brandt, Carlos Teixeira; Medeiros, Aldo da Cunha; de Oliveira, Ariano José Freitas; Jerônimo, Selma Maria; de Brito, Helena Marques Fonseca

    2007-01-01

    To investigate whether the alterations of the diverted colon segment mucosa, evidenced in fecal colitis, would be able to alter Bacterial Translocation (BT). Sixty-two Wistar male rats ranging from 220 to 320 grams of weight, were divided in two groups: A (Colostomy) and B (Control), with 31 animals each one. In group A, all animals underwent end colostomy, one stoma, in ascending colon; and in the 70th POD was injected in five rats, by rectal route diverted segment - 2 ml of a 0.9% saline solution in animals (A1 subgroup); in eight it was inoculated, by rectal route, 2 ml of a solution containing Escherichia coli ATCC 25922 (American Type Culture Collection), in a concentration of 10(8) Colony Forming Unit for milliliters (CFU/ml) - A2 Subgroup; in ten animals the same solution of E. coli was inoculated, in a concentration of 10(11) CFU/ml (A3 Subgroup); and in eight it was collected part of the mucus found in the diverted distal colonic segment for neutral sugars and total proteins dosage (A4 subgroup). The animals from the group B underwent the same procedures of group A, but with differences in the colostomy confection. In rats from subgroups A1, A2, A3, B1, B2, and B3 2 ml of blood were aspirated from the heart, and fragments from mesenteric lymphatic nodule, liver, spleen, lung and kidney taken for microbiological analysis, after their death. This analysis consisted of evidencing the presence of E. coli ATCC 25922 CFU. Mann-Whitney and ANOVA Tests were applied as analytic techniques for association of variables. The occurrence of BT was evidenced only in those animals in which inoculated concentration of E. coli ATCC 25922, reached levels of 10(11)CFU/ml, i.e. in Subgroups A3 and B3, although, being significantly greater (80%) in those animals without colostomy (subgroup B3) when compared to the ones with colostomy (20%) from the subgroup A3 (P subgroup A3, as in B3. Blood culture was considered positive in 60% of the animals from subgroup B3 and in 10% of

  15. Nasal Bacterial Colonization in Pediatric Epistaxis: The Role of Topical Antibacterial Treatment

    Science.gov (United States)

    Korkmaz, Mukadder; Çetinkol, Yeliz; Korkmaz, Hakan; Batmaz, Timur

    2016-01-01

    Background: Epistaxis is a common problem in childhood. It has been shown that children with recurrent epistaxis are more likely to have nasal colonization with Staphylococcus aureus. It has been suggested that low-grade inflammation, crusting and increased vascularity due to bacterial colonization contributes to the development of epistaxis in children. Aims: This study aimed to investigate the nasal colonization and treatment outcome in pediatric epistaxis patients. Study Design: Retrospective cross-sectional study. Methods: Charts of the pediatric patients referred to our university hospital otolaryngology outpatient clinics for the evaluation of epistaxis were reviewed. The patients whose nasal cultures had been taken at the first clinical visit comprised the study group. Results: Staphylococcus aureus was the most common bacteria grown. The presence of crusting and hypervascularity was not dependent on the type of bacterial growth and there was no relation between hypervascularity and crusting of the nasal mucosa. Thirty-six patients were evaluated for the outcome analysis. Resolution of bleeding was not dependent on nasal colonization; in patients with colonization, there was no difference between topical antibacterial and non-antibacterial treatments. Conclusion: Despite the high colonization rates, topical antibacterial treatment was not found superior to non-antibacterial treatment. Our study does not support the belief that bacterial colonization results in hypervascularity of the septal mucosa causing epistaxis since no relation was found between nasal colonization, hypervascularity and crusting. The role of bacterial colonization in pediatric epistaxis need to be further investigated and treatment protocols must be determined accordingly. PMID:27403392

  16. Nasal Bacterial Colonization in Pediatric Epistaxis: The Role of Topical Antibacterial Treatment

    Directory of Open Access Journals (Sweden)

    Mukaddder Korkmaz

    2016-04-01

    Full Text Available Background: Epistaxis is a common problem in childhood. It has been shown that children with recurrent epistaxis are more likely to have nasal colonization with Staphylococcus aureus. It has been suggested that low-grade inflammation, crusting and increased vascularity due to bacterial colonization contributes to the development of epistaxis in children. Aims: This study aimed to investigate the nasal colonization and treatment outcome in pediatric epistaxis patients. Study Design: Retrospective cross-sectional study. Methods: Charts of the pediatric patients referred to our university hospital otolaryngology outpatient clinics for the evaluation of epistaxis were reviewed. The patients whose nasal cultures had been taken at the first clinical visit comprised the study group. Results: Staphylococcus aureus was the most common bacteria grown. The presence of crusting and hypervascularity was not dependent on the type of bacterial growth and there was no relation between hypervascularity and crusting of the nasal mucosa. Thirty-six patients were evaluated for the outcome analysis. Resolution of bleeding was not dependent on nasal colonization; in patients with colonization, there was no difference between topical antibacterial and non-antibacterial treatments. Conclusion: Despite the high colonization rates, topical antibacterial treatment was not found superior to non-antibacterial treatment. Our study does not support the belief that bacterial colonization results in hypervascularity of the septal mucosa causing epistaxis since no relation was found between nasal colonization, hypervascularity and crusting. The role of bacterial colonization in pediatric epistaxis need to be further investigated and treatment protocols must be determined accordingly.

  17. Development of antifouling surfaces to reduce bacterial attachment

    Science.gov (United States)

    Graham, Mary Viola

    Bacteria are exceptionally good at adhering to surfaces and forming complex structures known as biofilms. This process, known as biofouling, can cause problems for infrastructure (eg, clogging and damaging pipes), for the food industry (eg, contamination of processing surfaces and equipment, and for the medical industry (eg, contamination of indwelling medical devices). Accordingly, multiple strategies have been explored to combat biofouling, including chemical modification of surfaces, development of antibiotic coatings, and more recently, the use of engineered surface topography. When designed properly, engineered surface topographies can significantly reduce bacterial surface attachment, ultimately limiting surface colonization. In this work, we hypothesized that the morphology, size, spacing, and surface pre-treatment of topographical features should directly correlate with the size and shape of target organisms, in order to reduce biofouling. Topographical features with size and spacing from 0.25 to 2 mum were fabricated in silicone elastomer and tested against rod shaped bacteria with an average size of 0.5 x 2 mum and spherical bacteria (cocci) ranging from 0.5 - 1 μm in diameter. Antifouling properties of the different topographical features were tested in both static and flow-based assays, and under oxygen plasma-treated (hydrophilic) and untreated (hydrophobic) surface conditions. We found that surface pre-treatment universally affects the ability bacteria to attach to surfaces, while surface topography limits attachment in a manner dependent on the bacterial size/shape and the size/spacing of the topography.

  18. Variation in local carrying capacity and the individual fate of bacterial colonizers in the phyllosphere

    Science.gov (United States)

    Remus-Emsermann, Mitja N P; Tecon, Robin; Kowalchuk, George A; Leveau, Johan H J

    2012-01-01

    Using a phyllosphere model system, we demonstrated that the term ‘carrying capacity', as it is commonly used in microbial ecology, needs to be understood as the sum of many ‘local carrying capacities' in order to better explain and predict the course and outcome of bacterial colonization of an environment. Using a green fluorescent protein-based bioreporter system for the quantification of reproductive success (RS) in individual Erwinia herbicola cells, we were able to reconstruct the contribution of individual immigrants to bacterial population sizes on leaves. Our analysis revealed that plant foliage represents to bacteria an environment where individual fate is determined by the local carrying capacity of the site where an immigrant cell lands. With increasing inoculation densities, the RS of most immigrants declined, suggesting that local carrying capacity under the tested conditions was linked to local nutrient availability. Fitting the observed experimental data to an adapted model of phyllosphere colonization indicated that there might exist three types of sites on leaves, which differ in their frequency of occurrence and local carrying capacity. Specifically, our data were consistent with a leaf environment that is characterized by few sites where individual immigrants can produce high numbers of offspring, whereas the remainder of the leaf offered an equal number of sites with low and medium RS. Our findings contribute to a bottom–up understanding of bacterial colonization of leaf surfaces, which includes a quantifiable role of chance in the experience at the individual level and in the outcome at the population level. PMID:22258099

  19. Nasopharyngeal co-colonization with Staphylococcus aureus and Streptococcus pneumoniae in children is bacterial genotype independent.

    NARCIS (Netherlands)

    Melles, D.C.; Bogaert, D.; Gorkink, R.F.; Peeters, J.K.; Moorhouse, M.J.; Ott, A.; Leeuwen, W.B. van; Simons, G.; Verbrugh, H.A.; Hermans, P.W.M.; Belkum, A. van

    2007-01-01

    Bacterial interference between Staphylococcus aureus and Streptococcus pneumoniae in the nasopharynx has been observed during colonization, which might have important clinical implications for the widespread use of pneumococcal conjugate vaccine in young children. This study aimed to determine

  20. Mechanisms and rates of bacterial colonization of sinking aggregates

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Grossart, H.P.; Ploug, H.

    2002-01-01

    Quantifying the rate at which bacteria colonize aggregates is a key to understanding microbial turnover of aggregates. We used encounter models based on random walk and advection-diffusion considerations to predict colonization rates from the bacteria's motility patterns (swimming speed, tumbling...... (0 to 2 s(-1)). The rates at which these bacteria colonized artificial aggregates (stationary and sinking) largely agreed with model predictions. We report several findings. (i) Motile bacteria rapidly colonize aggregates, whereas nonmotile bacteria do not. 00 Flow enhances colonization rates. (iii......) Tumbling strains colonize aggregates enriched with organic substrates faster than unenriched aggregates, while a nontumbling strain did not. (iv) Once on the aggregates, the bacteria may detach and typical residence time is about 3 h. Thus, there is a rapid exchange between attached and free bacteria. (v...

  1. Bacterial species colonizing the vagina of healthy women are not associated with race.

    Science.gov (United States)

    Beamer, May A; Austin, Michele N; Avolia, Hilary A; Meyn, Leslie A; Bunge, Katherine E; Hillier, Sharon L

    2017-06-01

    The vaginal microbiota of 36 white versus 25 black asymptomatic women were compared using both cultivation-dependent and -independent identification. Significant differences by race were found in colonization and density of bacterial species. However, exclusion of 12 women with bacterial vaginosis by Nugent criteria resulted in no significant differences by race. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Surface Topography Hinders Bacterial Surface Motility.

    Science.gov (United States)

    Chang, Yow-Ren; Weeks, Eric R; Ducker, William A

    2018-03-21

    We demonstrate that the surface motility of the bacterium, Pseudomonas aeruginosa, is hindered by a crystalline hemispherical topography with wavelength in the range of 2-8 μm. The motility was determined by the analysis of time-lapse microscopy images of cells in a flowing growth medium maintained at 37 °C. The net displacement of bacteria over 5 min is much lower on surfaces containing 2-8 μm hemispheres than on flat topography, but displacement on the 1 μm hemispheres is not lower. That is, there is a threshold between 1 and 2 μm for response to the topography. Cells on the 4 μm hemispheres were more likely to travel parallel to the local crystal axis than in other directions. Cells on the 8 μm topography were less likely to travel across the crowns of the hemispheres and were also more likely to make 30°-50° turns than on flat surfaces. These results show that surface topography can act as a significant barrier to surface motility and may therefore hinder surface exploration by bacteria. Because surface exploration can be a part of the process whereby bacteria form colonies and seek nutrients, these results help to elucidate the mechanism by which surface topography hinders biofilm formation.

  3. Protozoa and their bacterial prey colonize sterile soil fast

    DEFF Research Database (Denmark)

    Altenburger, Andreas; Ekelund, Flemming; Jacobsen, Carsten Suhr

    2010-01-01

    We know little about the ability of protozoa to colonize soils, including their successional patterns. To elucidate this issue, we investigated in which order different protozoan morpho-types colonize sterile soil. We used sterilized soils with different carbon content, and exposed them to the at......We know little about the ability of protozoa to colonize soils, including their successional patterns. To elucidate this issue, we investigated in which order different protozoan morpho-types colonize sterile soil. We used sterilized soils with different carbon content, and exposed them...... to the atmosphere for a period of 14 months. Bacteria and flagellates occurred in high numbers after 25 days. Ciliates reached high abundance levels after 137 days, followed by amoebae after 245 days. Numbers of distinguishable protozoan morpho-types increased until 245 days after exposure and declined thereafter...

  4. Bacterial colonization of the oral cavity of the BALB/c mouse.

    Science.gov (United States)

    Rodrigue, L; Barras, M J; Marcotte, H; Lavoie, M C

    1993-11-01

    The acquisition of the human oral bacterial flora follows a relatively well known sequence of succession that can be influenced by various host factors. These factors have not been studied in the mouse. In the present work, we followed the bacterial colonization of the oral cavity of mice from birth, and tested our mouse model for its suitability in studying the influence of weaning and puberty on the indigenous oral bacterial flora. We observed that the first colonizers were staphylococci, followed by lactobacilli. The proportions of these two predominant bacteria fluctuated for a period of 30-50 days, but evolved towards the proportions previously observed among the indigenous bacterial species of 6-8 week-old BALB/c male mice (predominantly Lactobacillus murinus and Staphylococcus aureus). The weaning period significantly altered the equilibrium among the oral bacterial flora. This equilibrium was not significantly modified during puberty.

  5. Control of bacterial adhesion and growth on honeycomb-like patterned surfaces.

    Science.gov (United States)

    Yang, Meng; Ding, Yonghui; Ge, Xiang; Leng, Yang

    2015-11-01

    It is a great challenge to construct a persistent bacteria-resistant surface even though it has been demonstrated that several surface features might be used to control bacterial behavior, including surface topography. In this study, we develop micro-scale honeycomb-like patterns of different sizes (0.5-10 μm) as well as a flat area as the control on a single platform to evaluate the bacterial adhesion and growth. Bacteria strains, Escherichia coli and Staphylococcus aureus with two distinct shapes (rod and sphere) are cultured on the platforms, with the patterned surface-up and surface-down in the culture medium. The results demonstrate that the 1 μm patterns remarkably reduce bacterial adhesion and growth while suppressing bacterial colonization when compared to the flat surface. The selective adhesion of the bacterial cells on the patterns reveals that the bacterial adhesion is cooperatively mediated by maximizing the cell-substrate contact area and minimizing the cell deformation, from a thermodynamic point of view. Moreover, study of bacterial behaviors on the surface-up vs. surface-down samples shows that gravity does not apparently affect the spatial distribution of the adherent cells although it indeed facilitates bacterial adhesion. Furthermore, the experimental results suggest that two major factors, i.e. the availability of energetically favorable adhesion sites and the physical confinements, contribute to the anti-bacterial nature of the honeycomb-like patterns. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Effects of easy-to-perform procedures to reduce bacterial colonization with Streptococcus mutans and Staphylococcus aureus on toothbrushes

    Science.gov (United States)

    Hage, Annina; Schneider, Katja; Schlösser, Karolin; Zimmermann, Ortrud; Hornecker, Else; Mausberg, Rainer F.; Frickmann, Hagen; Groß, Uwe; Ziebolz, Dirk

    2013-01-01

    It is well known that dental caries and periodontitis are the consequence of bacterial colonization and biofilm formation on the enamel surface. The continuous presence of bacterial biofilms on the tooth surface results in demineralization of the tooth enamel and induces an inflammatory reaction of the surrounding gums (gingivitis). The retention and survival of microorganisms on toothbrushes pose a threat of recontamination especially for certain patients at risk for systemic infections originating from the oral cavity, e.g., after T-cell depleted bone marrow transplantation. Thus, the effects of different decolonization schemes on bacterial colonization of toothbrushes were analyzed, in order to demonstrate their applicability to reduce the likelihood of (auto-)reinfections. Toothbrushes were intentionally contaminated with standardized suspensions of Streptococcus mutans or Staphylococcus aureus. Afterwards, the toothbrushes were exposed to rinsing under distilled water, rinsing and drying for 24 h, 0.2% chlorhexidine-based decolonization, or ultraviolet (UV) radiation. The remaining colony forming units were compared with freshly contaminated positive controls. Each experiment was nine-fold repeated. Bi-factorial variance analysis was performed; significance was accepted at P toothbrush model, the brush head type, or the acitivity state. Chlorhexidine-based decolonization was shown to be superior to rinsing and slightly superior to rinsing and drying for 24 h, while UV radiation was similarly effective as chlorhexidine. UV radiation was slightly less prone to species-dependent limitations of its decolonizing effects by bristle thickness of toothbrushes than chlorhexidin. Reduction of bacterial colonization of toothbrushes might reduce the risk of maintaining bacterial infections of the upper respiratory tract. Accordingly, respective procedures are advisable, particularly as they are cheap and easy to perform. PMID:24265940

  7. Estimation of algal colonization growth on mortar surface using a ...

    Indian Academy of Sciences (India)

    Estimation of algal colonization growth on mortar surface using a hybridization of machine learning and metaheuristic optimization ... The characteristics of the mortar samples, including surface roughness, porosity, surface pH, carbonated condition and type of cement, are employed as input factors for the analysing process ...

  8. Bacterial responses to a simulated colon tumor microenvironment

    NARCIS (Netherlands)

    Boleij, A.; Dutilh, B.E.; Kortman, G.A.M.; Roelofs, R.; Laarakkers, J.M.M.; Engelke, U.F.H.; Tjalsma, H.

    2012-01-01

    One of the few bacteria that have been consistently linked to colorectal cancer (CRC) is the opportunistic pathogen Streptococcus gallolyticus. Infections with this bacterium are generally regarded as an indicator for colonic malignancy, while the carriage rate of this bacterium in the healthy large

  9. Microbial Surface Colonization and Biofilm Development in Marine Environments.

    Science.gov (United States)

    Dang, Hongyue; Lovell, Charles R

    2016-03-01

    Biotic and abiotic surfaces in marine waters are rapidly colonized by microorganisms. Surface colonization and subsequent biofilm formation and development provide numerous advantages to these organisms and support critical ecological and biogeochemical functions in the changing marine environment. Microbial surface association also contributes to deleterious effects such as biofouling, biocorrosion, and the persistence and transmission of harmful or pathogenic microorganisms and their genetic determinants. The processes and mechanisms of colonization as well as key players among the surface-associated microbiota have been studied for several decades. Accumulating evidence indicates that specific cell-surface, cell-cell, and interpopulation interactions shape the composition, structure, spatiotemporal dynamics, and functions of surface-associated microbial communities. Several key microbial processes and mechanisms, including (i) surface, population, and community sensing and signaling, (ii) intraspecies and interspecies communication and interaction, and (iii) the regulatory balance between cooperation and competition, have been identified as critical for the microbial surface association lifestyle. In this review, recent progress in the study of marine microbial surface colonization and biofilm development is synthesized and discussed. Major gaps in our knowledge remain. We pose questions for targeted investigation of surface-specific community-level microbial features, answers to which would advance our understanding of surface-associated microbial community ecology and the biogeochemical functions of these communities at levels from molecular mechanistic details through systems biological integration. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  10. Polistes olivaceous decreases biotic surface colonization | Loo ...

    African Journals Online (AJOL)

    ... than the S group, which was reflected by a lower cariogenic bacterial count and a less compact biofilm especially after the third pulse. P. olivaceous suppresses bacteria growth and accelerates pH recovery. P. olivaceous may have stabilizing effect against cariogenic shift on the oral biofilm, preventing tooth decay.

  11. Cd1d-dependent regulation of bacterial colonization in the intestine of mice

    Science.gov (United States)

    Nieuwenhuis, Edward E.S.; Matsumoto, Tetsuya; Lindenbergh, Dicky; Willemsen, Rob; Kaser, Arthur; Simons-Oosterhuis, Ytje; Brugman, Sylvia; Yamaguchi, Keizo; Ishikawa, Hiroki; Aiba, Yuji; Koga, Yasuhiro; Samsom, Janneke N.; Oshima, Kenshiro; Kikuchi, Mami; Escher, Johanna C.; Hattori, Masahira; Onderdonk, Andrew B.; Blumberg, Richard S.

    2009-01-01

    The accumulation of certain species of bacteria in the intestine is involved in both tissue homeostasis and immune-mediated pathologies. The host mechanisms involved in controlling intestinal colonization with commensal bacteria are poorly understood. We observed that under specific pathogen–free or germ-free conditions, intragastric administration of Pseudomonas aeruginosa, E. coli, Staphylococcus aureus, or Lactobacillus gasseri resulted in increased colonization of the small intestine and bacterial translocation in mice lacking Cd1d, an MHC class I–like molecule, compared with WT mice. In contrast, activation of Cd1d-restricted T cells (NKT cells) with α-galactosylceramide caused diminished intestinal colonization with the same bacterial strains. We also found prominent differences in the composition of intestinal microbiota, including increased adherent bacteria, in Cd1d–/– mice in comparison to WT mice under specific pathogen–free conditions. Germ-free Cd1d–/– mice exhibited a defect in Paneth cell granule ultrastructure and ability to degranulate after bacterial colonization. In vitro, NKT cells were shown to induce the release of lysozyme from intestinal crypts. Together, these data support a role for Cd1d in regulating intestinal colonization through mechanisms that include the control of Paneth cell function. PMID:19349688

  12. a correlation study of lilcer status with. bacterial colonization and ...

    African Journals Online (AJOL)

    ing wound infection in patients with burn injury and those with chronic ulcers 0f the limbs. While wound swabs often culture mixed contaminants, biopsy specimens'usually reveal single organism growth. The depth 'of bacterial invasion may be a pointer to some dangerous complications that can arise from chronic ulcer.

  13. ‘Tidjanibacter massiliensis’ gen. nov., sp. nov., a new bacterial species isolated from human colon

    Directory of Open Access Journals (Sweden)

    M. Mailhe

    2017-05-01

    Full Text Available We report the summary of main characteristics of Tidjanibacter massiliensis strain Marseille-P3084T, a new bacterial species isolated from the liquid sample of the colon of a patient with a history of irritable bowel syndrome.

  14. Chlorhexidine Gluconate Dressings Reduce Bacterial Colonization Rates in Epidural and Peripheral Regional Catheters

    Directory of Open Access Journals (Sweden)

    Klaus Kerwat

    2015-01-01

    Full Text Available Introduction. Bacterial colonization of catheter tips is common in regional anesthesia and is a suspected risk factor for infectious complications. This is the first study evaluating the effect of CHG-impregnated dressings on bacterial colonization of regional anesthesia catheters in a routine clinical setting. Methods. In this prospective study, regional anesthesia catheter infection rates were examined in two groups of patients with epidural and peripheral regional catheters. In the first group, regional anesthesia was dressed with a conventional draping. The second group of patients underwent catheter dressing using a CHG-impregnated draping. Removed catheters and the insertion sites were both screened for bacterial colonization. Results. A total of 337 catheters from 308 patients were analysed. There was no significant reduction of local infections in either epidural or peripheral regional anesthesia catheters in both CHG and conventional groups. In the conventional group, 21% of the catheter tips and 41% of the insertion sites showed positive culture results. In the CHG-group, however, only 3% of the catheter tips and 8% of the insertion sites were colonised. Conclusion. CHG dressings significantly reduce bacterial colonization of the tip and the insertion site of epidural and peripheral regional catheters. However, no reductions in rates of local infections were seen.

  15. Spatial and temporal features of the growth of a bacterial species colonizing the zebrafish gut.

    Science.gov (United States)

    Jemielita, Matthew; Taormina, Michael J; Burns, Adam R; Hampton, Jennifer S; Rolig, Annah S; Guillemin, Karen; Parthasarathy, Raghuveer

    2014-12-16

    The vertebrate intestine is home to microbial ecosystems that play key roles in host development and health. Little is known about the spatial and temporal dynamics of these microbial communities, limiting our understanding of fundamental properties, such as their mechanisms of growth, propagation, and persistence. To address this, we inoculated initially germ-free zebrafish larvae with fluorescently labeled strains of an Aeromonas species, representing an abundant genus in the zebrafish gut. Using light sheet fluorescence microscopy to obtain three-dimensional images spanning the gut, we quantified the entire bacterial load, as founding populations grew from tens to tens of thousands of cells over several hours. The data yield the first ever measurements of the growth kinetics of a microbial species inside a live vertebrate intestine and show dynamics that robustly fit a logistic growth model. Intriguingly, bacteria were nonuniformly distributed throughout the gut, and bacterial aggregates showed considerably higher growth rates than did discrete individuals. The form of aggregate growth indicates intrinsically higher division rates for clustered bacteria, rather than surface-mediated agglomeration onto clusters. Thus, the spatial organization of gut bacteria both relative to the host and to each other impacts overall growth kinetics, suggesting that spatial characterizations will be an important input to predictive models of host-associated microbial community assembly. Our intestines are home to vast numbers of microbes that influence many aspects of health and disease. Though we now know a great deal about the constituents of the gut microbiota, we understand very little about their spatial structure and temporal dynamics in humans or in any animal: how microbial populations establish themselves, grow, fluctuate, and persist. To address this, we made use of a model organism, the zebrafish, and a new optical imaging technique, light sheet fluorescence microscopy

  16. Increased Risk of Pneumonia and Bronchiolitis after Bacterial Colonization of the Airways as Neonates

    DEFF Research Database (Denmark)

    Vissing, Nadja Hawwa; Chawes, Bo Lk; Bisgaard, Hans

    2013-01-01

    with susceptibility to pneumonia and bronchiolitis in young children. Objectives: To investigate the relation between neonatal airway colonization and pneumonia and bronchiolitis during the first three years of life. Methods: Participants comprised children of the COPSAC2000 cohort; a prospective birth cohort study...... physicians at the center. Analyses were adjusted for covariates associated pneumonia and bronchiolitisand bacterial airway colonization. Measurements and Main Results: Hypopharyngeal aspirates and full clinical follow-up until three years of age were available for 265 children. Of these, 56 (21%) neonates...... were colonized with S.pneumoniae, H.influenzae and/or M.catarrhalis at four weeks of age. Colonization with at least one of these microorganisms, (but not S.aureus), was significantly associated with increased incidence of pneumonia and bronchiolitis (adjusted Incidence Rate Ratio=1.79[1.29-2.48], p-value...

  17. Effects of colonization of a bacterial endophyte, Azospirillum sp. B510, on disease resistance in tomato.

    Science.gov (United States)

    Fujita, Moeka; Kusajima, Miyuki; Okumura, Yasuko; Nakajima, Masami; Minamisawa, Kiwamu; Nakashita, Hideo

    2017-08-01

    A plant growth-promoting bacteria, Azospirillum sp. B510, isolated from rice, can enhance growth and yield and induce disease resistance against various types of diseases in rice. Because little is known about the interaction between other plant species and this strain, we have investigated the effect of its colonization on disease resistance in tomato plants. Treatment with this strain by soil-drenching method established endophytic colonization in root tissues in tomato plant. The endophytic colonization with this strain-induced disease resistance in tomato plant against bacterial leaf spot caused by Pseudomonas syringae pv. tomato and gray mold caused by Botrytis cinerea. In Azospirillum-treated plants, neither the accumulation of SA nor the expression of defense-related genes was observed. These indicate that endophytic colonization with Azospirillum sp. B510 is able to activate the innate immune system also in tomato, which does not seem to be systemic acquired resistance.

  18. Tolerance to oxidative stress is required for maximal xylem colonization by the xylem-limited bacterial phytopathogen, Xylella fastidiosa.

    Science.gov (United States)

    Wang, Peng; Lee, Yunho; Igo, Michele M; Roper, M Caroline

    2017-09-01

    Bacterial plant pathogens often encounter reactive oxygen species (ROS) during host invasion. In foliar bacterial pathogens, multiple regulatory proteins are involved in the sensing of oxidative stress and the activation of the expression of antioxidant genes. However, it is unclear whether xylem-limited bacteria, such as Xylella fastidiosa, experience oxidative stress during the colonization of plants. Examination of the X. fastidiosa genome uncovered only one homologue of oxidative stress regulatory proteins, OxyR. Here, a knockout mutation in the X. fastidiosa oxyR gene was constructed; the resulting strain was significantly more sensitive to hydrogen peroxide (H 2 O 2 ) relative to the wild-type. In addition, during early stages of grapevine infection, the survival rate was 1000-fold lower for the oxyR mutant than for the wild-type. This supports the hypothesis that grapevine xylem represents an oxidative environment and that X. fastidiosa must overcome this challenge to achieve maximal xylem colonization. Finally, the oxyR mutant exhibited reduced surface attachment and cell-cell aggregation and was defective in biofilm maturation, suggesting that ROS could be a potential environmental cue stimulating biofilm development during the early stages of host colonization. © 2016 BSPP AND JOHN WILEY & SONS LTD.

  19. [Preoperatiove Airway Bacterial Colonization: the Missing Link between Non-small Cell Lung Cancer Following Lobectomy and Postoperative Pneumonia?

    Science.gov (United States)

    Gao, Ke; Lai, Yutian; Huang, Jian; Wang, Yifan; Wang, Xiaowei; Che, Guowei

    2017-04-20

    Surgical procedure is the main method of treating lung cancer. Meanwhile, postoperative pneumonia (POP) is the major cause of perioperative mortality in lung cancer surgery. The preoperative pathogenic airway bacterial colonization is an independent risk factor causing postoperative pulmonary complications (PPC). This cross-sectional study aimed to explore the relationship between preoperative pathogenic airway bacterial colonization and POP in lung cancer and to identify the high-risk factors of preoperative pathogenic airway bacterial colonization. A total of 125 patients with non-small cell lung cancer (NSCLC) underwent thoracic surgery in six hospitals of Chengdu between May 2015 and January 2016. Preoperative pathogenic airway bacterial colonization was detected in all patients via fiber bronchoscopy. Patients' PPC, high-risk factors, clinical characteristics, and the serum surfactant protein D (SP-D) level were also analyzed. The incidence of preoperative pathogenic airway bacterial colonization among NSCLC patients was 15.2% (19/125). Up to 22 strains were identified in the colonization positive group, with Gram-negative bacteria being dominant (86.36%, 19/22). High-risk factors of pathogenic airway bacterial colonization were age (≥75 yr) and smoking index (≥400 cigarettes/year). PPC incidence was significantly higher in the colonization-positive group (42.11%, 8/19) than that in the colonization-negative group (16.04%, 17/106)(P=0.021). POP incidence was significantly higher in the colonization-positive group (26.32%, 5/19) than that in the colonization-negative group (6.60%, 7/106)(P=0.019). The serum SP-D level of patients in the colonization-positive group was remarkably higher than that in the colonization-negative group [(31.25±6.09) vs (28.17±5.23)](P=0.023). The incidence of preoperative pathogenic airway bacterial colonization among NSCLC patients with POP was 41.67% (5/12). This value was 3.4 times higher than that among the patients without

  20. Colonization with the enteric protozoa Blastocystis is associated with increased diversity of human gut bacterial microbiota.

    Science.gov (United States)

    Audebert, Christophe; Even, Gaël; Cian, Amandine; Loywick, Alexandre; Merlin, Sophie; Viscogliosi, Eric; Chabé, Magali

    2016-05-05

    Alterations in the composition of commensal bacterial populations, a phenomenon known as dysbiosis, are linked to multiple gastrointestinal disorders, such as inflammatory bowel disease and irritable bowel syndrome, or to infections by diverse enteric pathogens. Blastocystis is one of the most common single-celled eukaryotes detected in human faecal samples. However, the clinical significance of this widespread colonization remains unclear, and its pathogenic potential is controversial. To address the issue of Blastocystis pathogenicity, we investigated the impact of colonization by this protist on the composition of the human gut microbiota. For that purpose, we conducted a cross-sectional study including 48 Blastocystis-colonized patients and 48 Blastocystis-free subjects and performed an Ion Torrent 16S rDNA gene sequencing to decipher the Blastocystis-associated gut microbiota. Here, we report a higher bacterial diversity in faecal microbiota of Blastocystis colonized patients, a higher abundance of Clostridia as well as a lower abundance of Enterobacteriaceae. Our results contribute to suggesting that Blastocystis colonization is usually associated with a healthy gut microbiota, rather than with gut dysbiosis generally observed in metabolic or infectious inflammatory diseases of the lower gastrointestinal tract.

  1. Effect of dietary monensin on the bacterial population structure of dairy cattle colonic contents.

    Science.gov (United States)

    McGarvey, Jeffery A; Hamilton, Scott W; DePeters, Edward J; Mitloehner, Frank M

    2010-02-01

    To determine the effect of monensin, a carboxylic polyether ionophore antibiotic, on the bacterial population structure of dairy cattle colonic contents, we fed six lactating Holstein cows a diet containing monensin (600 mg day(-1)) or an identical diet without monensin. Fresh waste samples were taken directly from the animals once a month for 3 months and assayed for their bacterial population structure via 16S rRNA gene sequence analysis. In total 6,912 16S rRNA genes were examined, comprising 345 and 315 operational taxonomic units (OTUs) from the monensin fed and control animals, respectively. Coverage estimates of the OTUs identified were 87.6% for the monensin fed and 88.3% for the control colonic content derived library. Despite this high level of coverage, no significant difference was found between the libraries down to the genus level. Thus we concluded that although monensin is believed to increase milk production in dairy cattle by altering the bacterial population structure within the bovine gastrointestinal tract, we were unable to identify any significant difference in the bacterial population structure of the colonic contents of monensin fed vs. the control dairy cattle, down to the genus level.

  2. Environmental Metabolomics of the Tomato Plant Surface Provides Insights on Salmonella enterica Colonization.

    Science.gov (United States)

    Han, Sanghyun; Micallef, Shirley A

    2016-05-15

    Foodborne illness-causing enteric bacteria are able to colonize plant surfaces without causing infection. We lack an understanding of how epiphytic persistence of enteric bacteria occurs on plants, possibly as an adaptive transit strategy to maximize chances of reentering herbivorous hosts. We used tomato (Solanum lycopersicum) cultivars that have exhibited differential susceptibilities to Salmonella enterica colonization to investigate the influence of plant surface compounds and exudates on enteric bacterial populations. Tomato fruit, shoot, and root exudates collected at different developmental stages supported growth of S. enterica to various degrees in a cultivar- and plant organ-dependent manner. S. enterica growth in fruit exudates of various cultivars correlated with epiphytic growth data (R(2) = 0.504; P = 0.006), providing evidence that plant surface compounds drive bacterial colonization success. Chemical profiling of tomato surface compounds with gas chromatography-time of flight mass spectrometry (GC-TOF-MS) provided valuable information about the metabolic environment on fruit, shoot, and root surfaces. Hierarchical cluster analysis of the data revealed quantitative differences in phytocompounds among cultivars and changes over a developmental course and by plant organ (P enterica growth, while fatty acids, including palmitic and oleic acids, were negatively correlated. We demonstrate that the plant surface metabolite landscape has a significant impact on S. enterica growth and colonization efficiency. This environmental metabolomics approach provides an avenue to understand interactions between human pathogens and plants that could lead to strategies to identify or breed crop cultivars for microbiologically safer produce. In recent years, fresh produce has emerged as a leading food vehicle for enteric pathogens. Salmonella-contaminated tomatoes represent a recurrent human pathogen-plant commodity pair. We demonstrate that Salmonella can utilize

  3. Sutures coated with antiseptic pomade to prevent bacterial colonization: a randomized clinical trial.

    Science.gov (United States)

    Cruz, Fernando; Leite, Fabiola; Cruz, Gustavo; Cruz, Silvia; Reis, Juarez; Pierce, Matthew; Cruz, Mauro

    2013-08-01

    The aim of this study was to assess if an antiseptic pomade could reduce the bacterial colonization on multifilament sutures. A randomized clinical trial was conducted with 40 volunteer patients of both sexes aged 18-70, randomly separated into experimental (n = 20) and control (n = 20) groups. The experimental group received pomade-coated sutures (iodoform + calendula) and the control group uncoated sutures. Two millimeters of the suture was harvested from each patient from the 1st to the 15th postoperative day. The bacteria that had adhered to them were cultured. The number of colony-forming units per milliliter (CFU/mL) was determined and the groups were compared using the Mann-Whitney statistical test (P antiseptic pomade was effective in reducing bacterial colonization on silk braided sutures. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. A simple technique to assess bacterial attachment to metal surfaces

    Digital Repository Service at National Institute of Oceanography (India)

    Sonak, S.; Bhosle, N.B.

    There are several methods to assess bacterial adhesion to metal surfaces. Although these methods are sensitive, they are time consuming and need expensive chemicals and instruments. Hence, their use in assessing bacterial adhesion is limited...

  5. Bacterial Colonization of Host Cells in the Absence of Cholesterol

    Science.gov (United States)

    Gilk, Stacey D.; Cockrell, Diane C.; Luterbach, Courtney; Hansen, Bryan; Knodler, Leigh A.; Ibarra, J. Antonio; Steele-Mortimer, Olivia; Heinzen, Robert A.

    2013-01-01

    Reports implicating important roles for cholesterol and cholesterol-rich lipid rafts in host-pathogen interactions have largely employed sterol sequestering agents and biosynthesis inhibitors. Because the pleiotropic effects of these compounds can complicate experimental interpretation, we developed a new model system to investigate cholesterol requirements in pathogen infection utilizing DHCR24−/− mouse embryonic fibroblasts (MEFs). DHCR24−/− MEFs lack the Δ24 sterol reductase required for the final enzymatic step in cholesterol biosynthesis, and consequently accumulate desmosterol into cellular membranes. Defective lipid raft function by DHCR24−/− MEFs adapted to growth in cholesterol-free medium was confirmed by showing deficient uptake of cholera-toxin B and impaired signaling by epidermal growth factor. Infection in the absence of cholesterol was then investigated for three intracellular bacterial pathogens: Coxiella burnetii, Salmonella enterica serovar Typhimurium, and Chlamydia trachomatis. Invasion by S. Typhimurium and C. trachomatis was unaltered in DHCR24−/− MEFs. In contrast, C. burnetii entry was significantly decreased in −cholesterol MEFs, and also in +cholesterol MEFs when lipid raft-associated αVβ3 integrin was blocked, suggesting a role for lipid rafts in C. burnetii uptake. Once internalized, all three pathogens established their respective vacuolar niches and replicated normally. However, the C. burnetii-occupied vacuole within DHCR24−/− MEFs lacked the CD63-postive material and multilamellar membranes typical of vacuoles formed in wild type cells, indicating cholesterol functions in trafficking of multivesicular bodies to the pathogen vacuole. These data demonstrate that cholesterol is not essential for invasion and intracellular replication by S. Typhimurium and C. trachomatis, but plays a role in C. burnetii-host cell interactions. PMID:23358892

  6. Evaluation of bacterial colonization in patients with the diagnosis of mycosis fungoides

    Directory of Open Access Journals (Sweden)

    Bengü Nisa Akay

    2014-12-01

    Full Text Available Background and Design: Mycosis fungoides (MF is the most common form of cutaneous T-cell lymphoma (CTCL. Bacterial infections are a common complication of MF/Sezary syndrome (SS. Staphylococcus aureus is the most common causes of skin infections in patients with MF/SS. However, the role of infectious agents and their effects on the clinical course is controversial. In this study, we aimed to assess the prevalence of the colonization of bacterial pathogens among individuals with MF/SS in comparison with control subjects. Materials and Methods: Sixty-six patients with MF/SS and 66 healthy control subjects were included in this study. The subjects were swabbed in the nose, throat and axilla and the samples were evaluated according to the Clinical Laboratory Standards Institute (CLSI criteria. Results: The mean age of the patients was 55.9±14.8 years (range: 21-84 years. Forty-eight patients were with ≤stage 2A, 18 were ≥stage 2B SS and MF. No statistically significant difference was observed in the frequency of pathogenic bacteria colonization in the nose and axilla between the two groups. However, in the throat it was statistically higher in MF/SS (p=0.001. There was no statistically significant difference between the two groups in terms of S.aureus colonization. The frequency of pathogenic bacteria colonization in the throat cultures were significant (p=0.004 for patients with late stage disease compared to those with early stages, but this was not shown in axilla and nose cultures. Conclusion: In this study, bacterial colonization in the throat and nasal carriage of S.aureus were found to be higher in patients with MF/SS. Further studies on the benefits of controlling this problem, possibly with simple and inexpensive methods that might ameliorates the symptoms such as itching, scaling and erythema are needed.

  7. RISA-HPLC analysis of lung bacterial colonizers of cystic fibrosis children.

    Science.gov (United States)

    Nazaret, S; Assade, F; Brothier, E; Freydière, A-M; Bellon, G; Cournoyer, B

    2009-01-01

    Microbiological analysis of sputum samples, from children affected by cystic fibrosis (CF) and showing signs of acute or chronic infections, is routinely performed by culture-dependent approaches involving selective media and biochemical tests. These identification schemes are time-consuming, and may lead to false negative results. The aim of this work was to evaluate the efficacy of a Ribosomal Intergenic Spacer Analysis (RISA) coupled to high performance liquid chromatography (HPLC) for the detection and monitoring of CF lung microbial colonizers including Staphylococcus aureus, Haemophilus influenzae, Pseudomonas aeruginosa, the Burkholderia cepacia complex, Stenotrophomonas maltophilia, and Achromobacter xylosoxidans. These RISA-HPLC analyses were performed over a 10-months period on infants (below 18 months) and children that were or were not yet known to be colonised by P. aeruginosa. The RISA-HPLC profiles were found specific of the patients' microbial communities. A specific P. aeruginosa RISA-HPLC peak corresponding to 550 bp PCR products was recorded, and used to investigate P. aeruginosa persistence through time and after various therapeutic treatments. The RISA-HPLC profiles showed the CF children to be colonized by few bacterial species, and sometimes revealed peaks corresponding to bacterial species that were not detected by the selective plating approaches. Significant RISA-HPLC infra-specific variations were observed for most bacterial colonizers of CF lungs except P. aeruginosa. These species could yield as much as 5 distinct RISA-HPLC peaks, with some of these profiles being strain-specific. RISA-HPLC shows a great potential for revealing colonization by novel emerging pathogens, and for evaluating the efficacy of therapeutic treatments on the global bacterial community of CF lungs.

  8. NMR study of the 1-13C glucose colon bacterial metabolism

    International Nuclear Information System (INIS)

    Briet, F.; Flourie, B.; Pochart, P.; Rambaud, J.C.; Desjeux, J.F.; Dallery, L.; Grivet, J.P.

    1994-01-01

    The aim of the study is to examine in-vitro and by nuclear magnetic resonance the biological pathways for the fermentation of the 1- 13 C labelled glucose (99 atoms percent) by human colon bacteria. The preparation of the bacterial suspension and the glucose degradation kinetics are presented; the NMR analysis sensitivity and quantification features are discussed and results are presented. 2 figs., 1 ref

  9. Increased risk of pneumonia and bronchiolitis after bacterial colonization of the airways as neonates.

    Science.gov (United States)

    Vissing, Nadja H; Chawes, Bo L K; Bisgaard, Hans

    2013-11-15

    The frequency of pneumonia and bronchiolitis exhibits considerable variation in otherwise healthy children, and suspected risk factors explain only a minor proportion of the variation. We hypothesized that alterations in the airway microbiome in early life may be associated with susceptibility to pneumonia and bronchiolitis in young children. To investigate the relation between neonatal airway colonization and pneumonia and bronchiolitis during the first 3 years of life. Participants comprised children of the Copenhagen Prospective Studies on Asthma in Childhood2000 (COPSAC2000) cohort, a prospective birth cohort study of 411 children born to mothers with asthma. Aspirates from the hypopharynx at age 4 weeks were cultured for Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Staphylococcus aureus. Clinical information on pneumonia and bronchiolitis within the first 3 years of life was prospectively collected by the research physicians at the center. Analyses were adjusted for covariates associated with pneumonia and bronchiolitis and bacterial airway colonization. Hypopharyngeal aspirates and full clinical follow-up until 3 years of age were available for 265 children. Of these, 56 (21%) neonates were colonized with S. pneumoniae, H. influenzae, and/or M. catarrhalis at 4 weeks of age. Colonization with at least one of these microorganisms (but not S. aureus) was significantly associated with increased incidence of pneumonia and bronchiolitis (adjusted incidence rate ratio, 1.79 [1.29-2.48]; P Neonatal airway colonization with S. pneumoniae, H. influenzae, or M. catarrhalis is associated with increased risk of pneumonia and bronchiolitis in early life independently of asthma. This suggests a role of pathogenic bacterial colonization of the airways in neonates for subsequent susceptibly to pneumonia and bronchiolitis.

  10. ‘Colibacter massiliensis’ gen. nov., sp. nov., a new bacterial species isolated from human left colon

    Directory of Open Access Journals (Sweden)

    M. Mailhe

    2017-05-01

    Full Text Available We present here the main characteristics of the strain Marseille-P2911 (= CSUR P2911=DSMZ 103304, a bacterial species isolated from the left colon liquid sample of a 60-year-old man.

  11. Inhibition of fungal colonization by Pseudoalteromonas tunicata provides a competitive advantage during surface colonization.

    Science.gov (United States)

    Franks, A; Egan, S; Holmström, C; James, S; Lappin-Scott, H; Kjelleberg, S

    2006-09-01

    The marine epiphytic bacterium Pseudoalteromonas tunicata produces a range of extracellular secondary metabolites that inhibit an array of common fouling organisms, including fungi. In this study, we test the hypothesis that the ability to inhibit fungi provides P. tunicata with an advantage during colonization of a surface. Studies on a transposon-generated antifungal-deficient mutant of P. tunicata, FM3, indicated that a long-chain fatty acid-coenzyme A ligase is involved in the production of a broad-range antifungal compound by P. tunicata. Flow cell experiments demonstrated that production of an antifungal compound provided P. tunicata with a competitive advantage against a marine yeast isolate during surface colonization. This compound enabled P. tunicata to disrupt an already established fungal biofilm by decreasing the number of yeast cells attached to the surface by 66% +/- 9%. For in vivo experiments, the wild-type and FM3 strains of P. tunicata were used to inoculate the surface of the green alga Ulva australis. Double-gradient denaturing gradient gel electrophoresis analysis revealed that after 48 h, the wild-type P. tunicata had outcompeted the surface-associated fungal community, whereas the antifungal-deficient mutant had no effect on the fungal community. Our data suggest that P. tunicata is an effective competitor against fungal surface communities in the marine environment.

  12. [Analysis of bacterial colonization associated with Gigaspora margarita spores by green fluorescence protein (GFP) marked technology].

    Science.gov (United States)

    Long, Liangkun; Yao, Qing; Ai, Yuncan; Zhu, Honghui

    2009-05-01

    We analyzed bacterial colonization associated with spores of arbuscular mycorrhizal fungi (AMF) Gigaspora margarita, to indicate their ecological niche, and to provide information for further researches on their populations or functions. Six bacteria strains (Peanibacillus sp. M060106-1, Peanibacillus sp. M061122-2, Peanibacillus sp. M061122-6, Bacillus sp. M061122-4, Bacillus sp. M061122-10 and Brevibacillus sp. M061122-12) isolated from G. margarita spores were tagged with green fluorescence protein (GFP) using the carrier plasmid pNF8 (gfp-mut1). We analyzed the ecological niche and population dynamics of tagged strains on G. margarita under different conditions by using fluorescent microscope and/or plate counts. Four strains (M060106-1, M061122-6, M061122-10 and M061122-12) were tagged with GFP, showing high plasmid stability. These tagged strains possessed the basic characteristics identical to their original strains and, hence, were fit for short-term study of environmental colonization. All four GFP-tagged strains colonized the spore wall of G. margarita, and M061122-6 and M061122-12 further colonized the fungal hyphae. Under different pH conditions,the population dynamic of each GFP-tagged strain on the spores showed the same trend, i.e. first increased and then decreased, and the effects on the population size varied with different pH value. GFP-tagged strains colonized the spores of low viability more easily than those of high viability, and the population dynamic on the spores of high viability was different for each tagged strain. The isolated bacteria associated with G. margarita spores can re-colonize the fungal spores, whereas their colonizing ability depends on their characteristics and environmental factors. These data contributes to the further understanding of populations and functions of AMF-associated bacteria.

  13. Nasal colonization and bacterial contamination of mobile phones carried by medical staff in the operating room.

    Directory of Open Access Journals (Sweden)

    Chih-Hsiang Chang

    Full Text Available Mobile phones (MPs have been an essential part of the lives of healthcare professionals and have improved communication, collaboration, and sharing of information. Nonetheless, the widespread use of MPs in hospitals has raised concerns of nosocomial infections, especially in areas requiring the highest hygienic standards such as operating rooms (ORs. This study evaluated the incidence of bacterial contamination of the MPs carried by medical staff working in the OR and determined its association with bacterial colonization of this personnel.This is an observational cohort study. Medical staffs working in the OR were asked to take bacterial cultures from their MPs, anterior nares, and dominant hands. To identify the relation between MP contamination and bacterial colonization of the medical staff, genotyping of Staphylococcus aureus (SA was done via Staphylococcus protein A gene (spa typing and pulsed-field gel electrophoresis (PFGE.A total of 216 swab samples taken from 72 medical-staff members were analyzed. The culture-positive rate was 98.1% (212/216. In 59 (27.3% samples, the bacteria were possible clinical pathogens. The anterior nares were the most common site of colonization by clinical pathogens (58.3%, 42/72, followed by MPs (13.9%, 10/72 and the dominant hand (9.7%, 7/72. SA was the most commonly isolated clinical pathogen and was found in 43 (19.9% samples. In 66 (94.3% of the 70 staff members for whom bacteria were detected on their MPs, the same bacteria were detected in nares or hand. Among 31 medical staff who were carriers of SA in the anterior nares or dominant hand, 8 (25.8% were found to have SA on their MPs, and genotyping confirmed the same SA strain in 7 (87.5% of them.A high rate of bacterial nasal colonization and MPs contamination were found among the OR medical staff. An MP may be a reservoir for pathogen contamination in the OR.

  14. Copper Is a Host Effector Mobilized to Urine during Urinary Tract Infection To Impair Bacterial Colonization.

    Science.gov (United States)

    Hyre, Amanda N; Kavanagh, Kylie; Kock, Nancy D; Donati, George L; Subashchandrabose, Sargurunathan

    2017-03-01

    Urinary tract infection (UTI) is a major global infectious disease affecting millions of people annually. Human urinary copper (Cu) content is elevated during UTI caused by uropathogenic Escherichia coli (UPEC). UPEC upregulates the expression of Cu efflux genes during clinical UTI in patients as an adaptive response to host-derived Cu. Whether Cu is mobilized to urine as a host response to UTI and its role in protection against UTI remain unresolved. To address these questions, we tested the hypothesis that Cu is a host effector mobilized to urine during UTI to limit bacterial growth. Our results reveal that Cu is mobilized to urine during UTI caused by the major uropathogens Proteus mirabilis and Klebsiella pneumoniae , in addition to UPEC, in humans. Ceruloplasmin, a Cu-containing ferroxidase, is found at higher levels in UTI urine than in healthy control urine and serves as the molecular source of urinary Cu during UTI. Our results demonstrate that ceruloplasmin decreases the bioavailability of iron in urine by a transferrin-dependent mechanism. Experimental UTI with UPEC in nonhuman primates recapitulates the increased urinary Cu content observed during clinical UTI. Furthermore, Cu-deficient mice are highly colonized by UPEC, indicating that Cu is involved in the limiting of bacterial growth within the urinary tract. Collectively, our results indicate that Cu is a host effector that is involved in protection against pathogen colonization of the urinary tract. Because urinary Cu levels are amenable to modulation, augmentation of the Cu-based host defense against UTI represents a novel approach to limiting bacterial colonization during UTI. Copyright © 2017 American Society for Microbiology.

  15. An Optimized Method for Extracting Bacterial RNA from Mouse Skin Tissue Colonized byMycobacterium ulcerans.

    Science.gov (United States)

    Robbe-Saule, Marie; Babonneau, Jérémie; Sismeiro, Odile; Marsollier, Laurent; Marion, Estelle

    2017-01-01

    Bacterial transcriptome analyses during host colonization are essential to decipher the complexity of the relationship between the bacterium and its host. RNA sequencing (RNA-seq) is a promising approach providing valuable information about bacterial adaptation, the host response and, in some cases, mutual tolerance underlying crosstalk, as recently observed in the context of Mycobacterium ulcerans infection. Buruli ulcer is caused by M. ulcerans . This neglected disease is the third most common mycobacterial disease worldwide. Without treatment, M. ulcerans provokes massive skin ulcers. A healing process may be observed in 5% of Buruli ulcer patients several months after the initiation of disease. This spontaneous healing process suggests that some hosts can counteract the development of the lesions caused by M. ulcerans . Deciphering the mechanisms involved in this process should open up new treatment possibilities. To this end, we recently developed the first mouse model for studies of the spontaneous healing process. We have shown that the healing process is based on mutual tolerance between the bacterium and its host. In this context, RNA-seq seems to be the most appropriate method for deciphering bacterial adaptation. However, due to the low bacterial load in host tissues, the isolation of mycobacterial RNA from skin tissue for RNA-seq analysis remains challenging. We developed a method for extracting and purifying mycobacterial RNA whilst minimizing the amount of host RNA in the sample. This approach was based on the extraction of bacterial RNA by a differential lysis method. The challenge in the development of this method was the choice of a lysis system favoring the removal of host RNA without damage to the bacterial cells. We made use of the thick, resistant cell wall of M. ulcerans to achieve this end.

  16. Milk sialyllactose influences colitis in mice through selective intestinal bacterial colonization.

    Science.gov (United States)

    Fuhrer, Andrea; Sprenger, Norbert; Kurakevich, Ekaterina; Borsig, Lubor; Chassard, Christophe; Hennet, Thierry

    2010-12-20

    Milk oligosaccharides contribute to the development of the intestinal environment by acting as decoy receptors for pathogens and as prebiotics, which promote the colonization of commensal bacteria. Here, using α2,3- and α2,6-sialyltransferase-deficient mice, we investigated the role of the sialylated milk oligosaccharides sialyl(α2,3)lactose and sialyl(α2,6)lactose on mucosal immunity. The exposure of newborn mice to milk containing or deficient in sialyllactose had no impact on the development of mucosal leukocyte populations. However, when challenged by dextran sulfate sodium (DSS) in drinking water, adult mice that had been fostered on sialyl(α2,3)lactose-deficient milk were more resistant to colitis compared with mice fostered on normal milk or sialyl(α2,6)lactose-deficient milk. Analysis of intestinal microbiota showed different colonization patterns depending on the presence or absence of sialyl(α2,3)lactose in the milk. Germ-free mice reconstituted with intestinal microbiota isolated from mice fed on sialyl(α2,3)lactose-deficient milk were more resistant to DSS-induced colitis than germ-free mice reconstituted with standard intestinal microbiota. Thus, exposure to sialyllactose during infancy affects bacterial colonization of the intestine, which influences the susceptibility to DSS-induced colitis in adult mice.

  17. The influence of surface modification on bacterial adhesion to titanium-based substrates.

    Science.gov (United States)

    Lorenzetti, Martina; Dogša, Iztok; Stošicki, Tjaša; Stopar, David; Kalin, Mitjan; Kobe, Spomenka; Novak, Saša

    2015-01-28

    This study examines bacterial adhesion on titanium-substrates used for bone implants. Adhesion is the most critical phase of bacterial colonization on medical devices. The surface of titanium was modified by hydrothermal treatment (HT) to synthesize nanostructured TiO2-anatase coatings, which were previously proven to improve corrosion resistance, affect the plasma protein adsorption, and enhance osteogenesis. The affinity of the anatase coatings toward bacterial attachment was studied by using a green fluorescent protein-expressing Escherichia coli (gfp-E. coli) strain in connection with surface photoactivation by UV irradiation. We also analyzed the effects of surface topography, roughness, charge, and wettability. The results suggested the dominant effects of the macroscopic surface topography, as well as microasperity at the surface roughness scale, which were produced during titanium machining, HT treatment, or both. Macroscopic grooves provided a preferential site for bacteria deposit within the valleys, while the microscopic roughness of the valleys determined the actual interaction surface between bacterium and substrate, resulting in an "interlocking" effect and undesired high bacterial adhesion on nontreated titanium. In the case of TiO2-coated samples, the nanocrystals reduced the width between the microasperities and thus added nanoroughness features. These factors decreased the contact area between the bacterium and the coating, with consequent lower bacterial adhesion (up to 50% less) in comparison to the nontreated titanium. On the other hand, the pronounced hydrophilicity of one of the HT-coated discs after pre-irradiation seemed to enhance the attachment of bacteria, although the increase was not statistically significant (p > 0.05). This observation may be explained by the acquired similar degree of wetting between gfp-E. coli and the coating. No correlation was found between the bacterial adhesion and the ζ-values of the samples in PBS, so the

  18. Impact of Neonatal Intensive Care Unit Admission on Bacterial Colonization of Donated Human Milk.

    Science.gov (United States)

    Elmekkawi, Amir; O'Connor, Deborah L; Stone, Debbie; Yoon, Eugene W; Larocque, Michael; McGeer, Allison; Unger, Sharon

    2018-05-01

    Unpasteurized human donor milk typically contains a variety of bacteria. The impact of neonatal intensive care unit (NICU) admission of the donor's infant and duration of lactation on bacterial contamination of human milk is unknown. Research aim: This study aimed (a) to describe the frequency/concentration of skin commensal bacteria and pathogens in unpasteurized human donor milk and (b) to assess the impact of NICU admission and (c) the duration of milk expression on bacterial colonization of donated milk. The authors conducted a retrospective cohort study of human milk donated to the Rogers Hixon Ontario Human Milk Bank from January 2013 to June 2014. Milk samples from each donor were cultured every 2 weeks. The study included 198 donor mothers, of whom 63 had infants admitted to the NICU. Of 1,289 cultures obtained, 1,031 (80%) had detectable bacterial growth and 363 (28%) yielded bacterial growth in excess of 10 7 cfu/L, a local threshold for allowable bacteria prior to pasteurization. The mean (standard deviation) donation period per donor was 13.0 (7.5) weeks. Milk from mothers with NICU exposure had significantly higher concentrations of commensals, but not pathogens, at every time period compared with other mothers. For every 1-month increase in donation from all donors, the odds ratio of presence of any commensal in milk increased by 1.13 (95% confidence interval [1.03, 1.23]) and any pathogen by 1.31 (95% confidence interval [1.20, 1.43]). Commensal bacteria were more abundant in donor milk expressed from mothers exposed to neonatal intensive care. Bacterial contamination increased over the milk donation period.

  19. Bacterial Cell Surface Damage Due to Centrifugal Compaction

    NARCIS (Netherlands)

    Peterson, Brandon W.; Sharma, Prashant K.; van der Mei, Henny C.; Busscher, Henk J.

    Centrifugal damage has been known to alter bacterial cell surface properties and interior structures, including DNA. Very few studies exist on bacterial damage caused by centrifugation because of the difficulty in relating centrifugation speed and container geometry to the damage caused. Here, we

  20. Electrochemical characterization of the bacterial cell surface

    NARCIS (Netherlands)

    Wal, van der A.

    1996-01-01


    Bacterial cells are ubiquitous in natural environments and also play important roles in domestic and industrial processes. They are found either suspended in the aqueous phase or attached to solid particles. The adhesion behaviour of bacteria is influenced by the physico-chemical

  1. Abundance of bacterial and diatom fouling on various surfaces

    Digital Repository Service at National Institute of Oceanography (India)

    PrabhaDevi

    Abundance of bacterial and diatom fouling on aluminium, fibreglass and stainless steel were studied from Dona Paula waters of the Zuari Estuary. Both these forms were reversibly attached in large numbers to surfaces during the initial 24 hr...

  2. Electrostatic behavior of the charge-regulated bacterial cell surface.

    Science.gov (United States)

    Hong, Yongsuk; Brown, Derick G

    2008-05-06

    The electrostatic behavior of the charge-regulated surfaces of Gram-negative Escherichia coli and Gram-positive Bacillus brevis was studied using numerical modeling in conjunction with potentiometric titration and electrophoretic mobility data as a function of solution pH and electrolyte composition. Assuming a polyelectrolytic polymeric bacterial cell surface, these experimental and numerical analyses were used to determine the effective site numbers of cell surface acid-base functional groups and Ca(2+) sorption coefficients. Using effective site concentrations determined from 1:1 electrolyte (NaCl) experimental data, the charge-regulation model was able to replicate the effects of 2:1 electrolyte (CaCl(2)), both alone and as a mixture with NaCl, on the measured zeta potential using a single Ca(2+) surface binding constant for each of the bacterial species. This knowledge is vital for understanding how cells respond to changes in solution pH and electrolyte composition as well as how they interact with other surfaces. The latter is especially important due to the widespread use of the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory in the interpretation of bacterial adhesion. As surface charge and surface potential both vary on a charge-regulated surface, accurate modeling of bacterial interactions with surfaces ultimately requires use of an electrostatic model that accounts for the charge-regulated nature of the cell surface.

  3. Novel salicylazo polymers for colon drug delivery: dissolving polymers by means of bacterial degradation.

    Science.gov (United States)

    Saphier, Sigal; Karton, Yishai

    2010-02-01

    Novel azo polymers were prepared for colonic drug delivery with a release mechanism based on structural features of azo derivatives designed for rapid bacterial degradation leading to soluble polymers. Two Salicylazo derivatives were prepared and conjugated as side chains at different ratios to methacrylic acid-methyl methacrylate copolymers (Eudragits). The azo compounds were designed to have a hydrophilic and a hydrophobic part on opposite sides of the azo bond. Upon reduction of the azo bonds, the hydrophobic part is released, resulting in a more water soluble polymer. The solubility of the polymeric films was studied relative to Eudragit S known to dissolve toward the end of the small intestine. One of the two azo derivatives prepared gave rise to polymers, which showed reduced solubility relative to Eudragit S. These polymers were subjected to reduction tests in anaerobic rat cecal suspensions by following the release of the hydrophobic product. Reduction rate was found to be rapid, comparable to that of Sulfasalazine. Studies on the azopolymeric films in anaerobic rat cecal suspensions, showed that these polymers dissolve faster than in sterilized suspensions. Solid dosage forms may be coated with these polymers to provide an efficient delivery system to the colon with a rapid release mechanism. (c) 2009 Wiley-Liss, Inc. and the American Pharmacists Association.

  4. Bacterial colonization of the ovarian bursa in dogs with clinically suspected pyometra and in controls.

    Science.gov (United States)

    Rubio, Alejandro; Boyen, Filip; Tas, Olaf; Kitshoff, Adriaan; Polis, Ingeborgh; Van Goethem, Bart; de Rooster, Hilde

    2014-10-15

    Septic peritonitis occurs relatively commonly in dogs. Secondary septic peritonitis is usually associated with perforation of intestines or infected viscera, such as the uterus in pyometra cases. The aim of this study was to evaluate the bacterial flora in the ovarian bursae of intact bitches as a potential source of contamination. One hundred forty dogs, clinically suspected of pyometra, were prospectively enrolled. The control group consisted of 26 dogs that underwent elective ovariohysterectomies and 18 dogs with mammary gland tumors that were neutered at the time of mastectomy. Bacteriology samples were taken aseptically at the time of surgery from the bursae and the uterus in all dogs. Twenty-two dogs that were clinically suspected of pyometra had sterile uterine content ("mucometra" cases); the remaining 118 had positive uterine cultures ("pyometra" cases) and septic peritoneal fluid was present in 10% of these cases. Of the 118 pyometra cases, 9 had unilateral and 15 had bilateral bacterial colonization of their ovarian bursae. However, the bacteria from the ovarian bursa were similar to those recovered from the uterine pus in only half of the cases. Furthermore, positive bursae were also seen in one mucometra dog (unilateral) and in four control dogs (two unilateral and two bilateral). The data illustrate that the canine ovarian bursa can harbor bacteria. The biological importance of these isolations remains unclear. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. The role of innate immune responses in the outcome of interspecies competition for colonization of mucosal surfaces.

    Directory of Open Access Journals (Sweden)

    Elena S Lysenko

    2005-09-01

    Full Text Available Since mucosal surfaces may be simultaneously colonized by multiple species, the success of an organism may be determined by its ability to compete with co-inhabitants of its niche. To explore the contribution of host factors to polymicrobial competition, a murine model was used to study the initiation of colonization by Haemophilus influenzae and Streptococcus pneumoniae. Both bacterial species, which occupy a similar microenvironment within the nasopharynx, persisted during colonization when given individually. Co-colonization, however, resulted in rapid clearance of S. pneumoniae from the upper respiratory tract, associated with increased recruitment of neutrophils into paranasal spaces. Systemic depletion of either neutrophil-like cells or complement was sufficient to eliminate this competitive effect, indicating that clearance was likely due to enhanced opsonophagocytic killing. The hypothesis that modulation of opsonophagocytic activity was responsible for host-mediated competition was tested using in vitro killing assays with elicited neutrophil-like cells. Components of H. influenzae (but not S. pneumoniae stimulated complement-dependent phagocytic killing of S. pneumoniae. Thus, the recruitment and activation of neutrophils through selective microbial pattern recognition may underlie the H. influenzae-induced clearance of S. pneumoniae. This study demonstrates how innate immune responses may mediate competitive interactions between species and dictate the composition of the colonizing flora.

  6. Comparison of bacterial quantities in left and right colon biopsies and faeces.

    Science.gov (United States)

    Lyra, Anna; Forssten, Sofia; Rolny, Peter; Wettergren, Yvonne; Lahtinen, Sampo J; Salli, Krista; Cedgård, Lennart; Odin, Elisabeth; Gustavsson, Bengt; Ouwehand, Arthur C

    2012-08-28

    To compare quantities of predominant and pathogenic bacteria in mucosal and faecal samples. Twenty patients undergoing diagnostic colonoscopy with endoscopically and histologically normal mucosa were recruited to the study, 14 subjects of which also supplied faecal (F) samples between 15 d to 105 d post colonoscopy. Mucosal biopsies were taken from each subject from the midportion of the ascending colon (right side samples, RM) and the sigmoid (left side samples, LM). Predominant intestinal and mucosal bacteria including clostridial 16S rRNA gene clusters IV and XIVab, Bacteroidetes, Enterobacteriaceae, Bifidobacterium spp., Akkermansia muciniphila (A. muciniphila), Veillonella spp., Collinsella spp., Faecalibacterium prausnitzii (F. prausnitzii) and putative pathogens such as Escherichia coli (E. coli), Clostridium difficile (C. difficile), Helicobacter pylori (H. pylori) and Staphylococcus aureus (S. aureus) were analysed by quantitative polymerase chain reaction (qPCR). Host DNA was quantified from the mucosal samples with human glyceraldehyde 3-phosphate dehydrogenase gene targeting qPCR. Paired t tests and the Pearson correlation were applied for statistical analysis. The most prominent bacterial groups were clostridial groups IV and XIVa+b and Bacteroidetes and bacterial species F. prausnitzii in both sample types. H. pylori and S. aureus were not detected and C. difficile was detected in only one mucosal sample and three faecal samples. E. coli was detected in less than half of the mucosal samples at both sites, but was present in all faecal samples. All detected bacteria, except Enterobacteriaceae, were present at higher levels in the faeces than in the mucosa, but the different locations in the colon presented comparable quantities (RM, LM and F followed by P(1) for RM vs F, P(2) for LM vs F and P(3) for RM vs LM: 4.17 ± 0.60 log(10)/g, 4.16 ± 0.56 log(10)/g, 5.88 ± 1.92 log(10)/g, P(1) = 0.011, P(2) = 0.0069, P(3) = 0.9778 for A. muciniphila; 6.25 ± 1

  7. Reversibility of bacterial adhesion at an electrode surface

    NARCIS (Netherlands)

    Poortinga, AT; Busscher, HJ; Bos, R.R.M.

    2001-01-01

    Deposition of four bacterial strains from a 1 mM potassium phosphate buffer (pH 7) to an indium tin oxide (ITO) electrode surface has been studied in a parallel plate flow chamber at three electrode potentials (-0.2, 0.1, and 0.5 V). Capacitance measurements demonstrated that the ITO surface was

  8. Electric double layer interactions in bacterial adhesion to surfaces

    NARCIS (Netherlands)

    Poortinga, AT; Norde, W; Busscher, HJ; Bos, R.R.M.

    2002-01-01

    The DLVO (Derjaguin, Landau, Verwey, Overbeek) theory was originally developed to describe interactions between non-biological lyophobic colloids such as polystyrene particles, but is also used to describe bacterial adhesion to surfaces. Despite the differences between the surface of bacteria and

  9. Periodontal bacterial colonization in synovial tissues exacerbates collagen-induced arthritis in B10.RIII mice.

    Science.gov (United States)

    Chukkapalli, Sasanka; Rivera-Kweh, Mercedes; Gehlot, Prashasnika; Velsko, Irina; Bhattacharyya, Indraneel; Calise, S John; Satoh, Minoru; Chan, Edward K L; Holoshitz, Joseph; Kesavalu, Lakshmyya

    2016-07-12

    It has been previously hypothesized that oral microbes may be an etiological link between rheumatoid arthritis (RA) and periodontal disease. However, the mechanistic basis of this association is incompletely understood. Here, we investigated the role of periodontal bacteria in induction of joint inflammation in collagen-induced arthritis (CIA) in B10.RIII mice. CIA-prone B10.RIII mice were infected orally with a polybacterial mixture of Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia for 24 weeks before induction of CIA. The ability of polybacterial mixture to colonize the periodontium and induce systemic response, horizontal alveolar bone resorption in infected B10.RIII mice was investigated. Arthritis incidence, severity of joint inflammation, pannus formation, skeletal damage, hematogenous dissemination of the infection, matrix metalloproteinase 3 (MMP3) levels, and interleukin-17 expression levels were evaluated. B10.RIII mice had gingival colonization with all three bacteria, higher levels of anti-bacterial immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies, significant alveolar bone resorption, and hematogenous dissemination of P. gingivalis to synovial joints. Infected B10.RIII mice had more severe arthritis, and higher serum matrix metalloproteinase 3 levels and activity. Histopathological analysis showed increased inflammatory cell infiltration, destruction of articular cartilage, erosions, and pannus formation. Additionally, involved joints showed had expression levels of interleukin-17. These findings demonstrate that physical presence of periodontal bacteria in synovial joints of B10.RIII mice with collagen-induced arthritis is associated with arthritis exacerbation, and support the hypothesis that oral bacteria, specifically P. gingivalis, play a significant role in augmenting autoimmune arthritis due to their intravascular dissemination to the joints.

  10. Effects of bacterial vaginosis-associated bacteria and sexual intercourse on vaginal colonization with the probiotic Lactobacillus crispatus CTV-05.

    Science.gov (United States)

    Ngugi, Benjamin M; Hemmerling, Anke; Bukusi, Elizabeth A; Kikuvi, Gideon; Gikunju, Joseph; Shiboski, Stephen; Fredricks, David N; Cohen, Craig R

    2011-11-01

    Several fastidious bacteria have been associated with bacterial vaginosis (BV), but their role in lactobacilli recolonization failure is unknown. We studied the effect of 7 BV-associated bacterial species and 2 Lactobacillus species on vaginal colonization with Lactobacillus crispatus CTV-05 (LACTIN-V). Twenty-four women with BV were given a 5-day course of metronidazole vaginal gel and then randomized 3:1 to receive either LACTIN-V or placebo applied vaginally once daily for 5 initial consecutive days, followed by a weekly application over 2 weeks. Vaginal swabs for L. crispatus CTV-05 culture and 9 bacterium-specific 16S rRNA gene quantitative polymerase chain reaction assays were analyzed on several study visits for the 18 women receiving LACTIN-V. Vaginal colonization with CTV-05 was achieved in 61% of the participants receiving LACTIN-V at either day 10 or day 28 visit and 44% at day 28. Participants not colonized with CTV-05 had generally higher median concentrations of BV-associated bacteria compared to those who colonized. Between enrollment and day 28, the median concentration of Gardnerella vaginalis minimally reduced from 10 to 10 16S rRNA gene copies per swab in women who colonized with CTV-05 but increased from 10 to 10 in those who failed to colonize (P = 0.19). Similarly, the median concentration of Atopobium spp. reduced from 10 16S rRNA gene copies per swab to below limit of detection in women who colonized with CTV-05, but increased from 10 to 10 in those who failed to colonize (P = 0.04). The presence of endogenous L. crispatus at enrollment was found to be significantly associated with a reduced odds of colonization with CTV-05 on day 28 (P = 0.003), and vaginal intercourse during the study significantly impaired successful CTV-05 colonization (P = 0.018). Vaginal concentration of certain BV-associated bacteria, vaginal intercourse during treatment, and the presence of endogenous L. crispatus at enrollment predict colonization with probiotic

  11. Reduced bacterial growth and increased osteoblast proliferation on titanium with a nanophase TiO2surface treatment.

    Science.gov (United States)

    Bhardwaj, Garima; Webster, Thomas J

    2017-01-01

    The attachment and initial growth of bacteria on an implant surface dictates the progression of infection. Treatment often requires aggressive antibiotic use, which does not always work. To overcome the difficulties faced in systemic and local antibiotic delivery, scientists have forayed into using alternative techniques, which includes implant surface modifications that prevent initial bacterial adhesion, foreign body formation, and may offer a controlled inflammatory response. The current study focused on using electrophoretic deposition to treat titanium with a nanophase titanium dioxide surface texture to reduce bacterial adhesion and growth. Two distinct nanotopographies were analyzed, Ti-160, an antimicrobial surface designed to greatly reduce bacterial colonization, and Ti-120, an antimicrobial surface with a topography that upregulates osteoblast activity while reducing bacterial colonization; the number following Ti in the nomenclature represents the atomic force microscopy root-mean-square roughness value in nanometers. There was a 95.6% reduction in Staphylococcus aureus (gram-positive bacteria) for the Ti-160-treated surfaces compared to the untreated titanium alloy controls. There was a 90.2% reduction in Pseudomonas aeruginosa (gram-negative bacteria) on Ti-160-treated surfaces compared to controls. For ampicillin-resistant Escherichia coli , there was an 81.1% reduction on the Ti-160-treated surfaces compared to controls. Similarly for surfaces treated with Ti-120, there was an 86.8% reduction in S. aureus , an 82.1% reduction in P. aeruginosa , and a 48.6% reduction in ampicillin-resistant E. coli . The Ti-120 also displayed a 120.7% increase at day 3 and a 168.7% increase at day 5 of osteoblast proliferation over standard titanium alloy control surfaces. Compared to untreated surfaces, Ti-160-treated titanium surfaces demonstrated a statistically significant 1 log reduction in S. aureus and P. aeruginosa , whereas Ti-120 provided an additional

  12. Barriers to bacterial motility on unsaturated surfaces

    DEFF Research Database (Denmark)

    Dechesne, Arnaud; Smets, Barth F.

    2013-01-01

    Our knowledge of the spatial organization and spatial dynamics of microbial populations in soil at a scale close to that of the microorganisms is scarce. While passive dispersal via water ow or soil biota is probably a major dispersal route, it is reasonable to consider that active dispersal also...... characterized by complex 3D geometry and variable hydration. To approach these questions we take advantage of the Porous Surface Model (PSM) a unique experimental platform that allows direct monitoring of microbial motion under precisely controlled matric potential. Using gfp-tagged Pseudomonas strains...

  13. Xylella fastidiosa outer membrane vesicles modulate plant colonization by blocking attachment to surfaces.

    Science.gov (United States)

    Ionescu, Michael; Zaini, Paulo A; Baccari, Clelia; Tran, Sophia; da Silva, Aline M; Lindow, Steven E

    2014-09-16

    Outer membrane vesicles (OMVs) of Gram-negative bacteria have been studied intensively in recent years, primarily in their role in delivering virulence factors and antigens during pathogenesis. However, the near ubiquity of their production suggests that they may play other roles, such as responding to envelope stress or trafficking various cargoes to prevent dilution or degradation by other bacterial species. Here we show that OMVs produced by Xylella fastidiosa, a xylem-colonizing plant pathogenic bacterium, block its interaction with various surfaces such as the walls of xylem vessels in host plants. The release of OMVs was suppressed by the diffusible signal factor-dependent quorum-sensing system, and a X. fastidiosa ΔrpfF mutant in which quorum signaling was disrupted was both much more virulent to plants and less adhesive to glass and plant surfaces than the WT strain. The higher virulence of the ΔrpfF mutant was associated with fivefold higher numbers of OMVs recovered from xylem sap of infected plants. The frequency of attachment of X. fastidiosa to xylem vessels was 20-fold lower in the presence of OMVs than in their absence. OMV production thus is a strategy used by X. fastidiosa cells to adjust attachment to surfaces in its transition from adhesive cells capable of insect transmission to an "exploratory" lifestyle for systemic spread within the plant host which would be hindered by attachment. OMV production may contribute to the movement of other bacteria in porous environments by similarly reducing their contact with environmental constituents.

  14. Colonic transit time is related to bacterial metabolism and mucosal turnover in the gut

    DEFF Research Database (Denmark)

    Roager, Henrik Munch; Hansen, Lea Benedicte Skov; Bahl, Martin Iain

    2016-01-01

    Little is known about how colonic transit time relates to human colonic metabolism and its importance for host health, although a firm stool consistency, a proxy for a long colonic transit time, has recently been positively associated with gut microbial richness. Here, we show that colonic transit...... time in humans, assessed using radio-opaque markers, is associated with overall gut microbial composition, diversity and metabolism. We find that a long colonic transit time associates with high microbial richness and is accompanied by a shift in colonic metabolism from carbohydrate fermentation...

  15. Microbial colonization in diverse surface soil types in Surtsey and diversity analysis of its subsurface microbiota

    Science.gov (United States)

    Marteinsson, V.; Klonowski, A.; Reynisson, E.; Vannier, P.; Sigurdsson, B. D.; Ólafsson, M.

    2015-02-01

    Colonization of life on Surtsey has been observed systematically since the formation of the island 50 years ago. Although the first colonisers were prokaryotes, such as bacteria and blue-green algae, most studies have been focused on the settlement of plants and animals but less on microbial succession. To explore microbial colonization in diverse soils and the influence of associated vegetation and birds on numbers of environmental bacteria, we collected 45 samples from different soil types on the surface of the island. Total viable bacterial counts were performed with the plate count method at 22, 30 and 37 °C for all soil samples, and the amount of organic matter and nitrogen (N) was measured. Selected samples were also tested for coliforms, faecal coliforms and aerobic and anaerobic bacteria. The subsurface biosphere was investigated by collecting liquid subsurface samples from a 181 m borehole with a special sampler. Diversity analysis of uncultivated biota in samples was performed by 16S rRNA gene sequences analysis and cultivation. Correlation was observed between nutrient deficits and the number of microorganisms in surface soil samples. The lowest number of bacteria (1 × 104-1 × 105 cells g-1) was detected in almost pure pumice but the count was significantly higher (1 × 106-1 × 109 cells g-1) in vegetated soil or pumice with bird droppings. The number of faecal bacteria correlated also to the total number of bacteria and type of soil. Bacteria belonging to Enterobacteriaceae were only detected in vegetated samples and samples containing bird droppings. The human pathogens Salmonella, Campylobacter and Listeria were not in any sample. Both thermophilic bacteria and archaea 16S rDNA sequences were found in the subsurface samples collected at 145 and 172 m depth at 80 and 54 °C, respectively, but no growth was observed in enrichments. The microbiota sequences generally showed low affiliation to any known 16S rRNA gene sequences.

  16. Colonic transit time relates to bacterial metabolism and mucosal turnover in the human gut

    DEFF Research Database (Denmark)

    Roager, Henrik Munch; Hansen, Lea Benedicte Skov; Bahl, Martin Iain

    Little is known about how colonic transit time relates to human colonic metabolism, and its importance for host health, although stool consistency, a proxy for colonic transit time, has recently been negatively associated with gut microbial richness. To address the relationships between colonic...... transit time and the gut microbial composition and metabolism, we assessed the colonic transit time of 98 subjects using radiopaque markers, and profiled their gut microbiota by16S rRNA gene sequencingand their urine metabolome by ultra performance liquid chromatography mass spectrometry. Based...... on correlation analyses,we show that colonic transit time is associated with overall gutmicrobial composition, diversity and metabolism. A relatively prolonged colonic transit time associates with high microbial species richness and a shift in colonic metabolismfrom carbohydrate fermentation to protein...

  17. Colonic transit time is related to bacterial metabolism and mucosal turnover in the human gut

    DEFF Research Database (Denmark)

    Roager, Henrik Munch; Hansen, Lea Benedicte Skov; Bahl, Martin Iain

    Little is known about how colonic transit time relates to human colonic metabolism, and its importance for host health, although stool consistency, a proxy for colonic transit time, has recently been negatively associated with gut microbial richness. To address the relationships between colonic...... transit time and the gut microbial composition and metabolism, we assessed the colonic transit time of 98 subjects using radiopaque markers, and profiled their gut microbiota by16S rRNA gene sequencing and their urine metabolome by ultra performance liquid chromatography mass spectrometry. Based...... on correlation analyses, we show that colonic transit time is associated with overall gut microbial composition, diversity and metabolism. A relatively prolonged colonic transit time associates with high microbial species richness and a shift in colonic metabolism from carbohydrate fermentation to protein...

  18. An in vivo comparison of internal bacterial colonization in two dental implant systems: identification of a pathogenic reservoir.

    Science.gov (United States)

    Mawhinney, Joanne; Connolly, Eimear; Claffey, Noel; Moran, Gary; Polyzois, Ioannis

    2015-04-01

    The aim of this study was to compare internal bacterial colonization in two implant systems, one screw root form (SRF) with an external hexagon connection and one plateau root form (PRF) with a Morse taper internal connection. Thirty-two implants; 12 SRF and 20 PRF, were sampled in 15 patients. All implants had been in function for at least 6 months prior to sampling. The implant restoration was removed and 10 µl of sterile saline was introduced into the implant well via a sterile glass syringe. The saline was drawn back up and transferred to the laboratory for microbiological analysis. The number of aerobic and anaerobic colony forming units per millilitre was determined and the dominant micro-organism in each sample was identified by 16s rRNA gene amplicon sequencing. There was a significant difference between bleeding on probing around the SRF implants (3%) and the PRF implants (28%) (p = 0.0496). Bacterial colonization was identified at 11 SRF and 19 PRF implants. The numbers of anaerobic bacteria recovered from PRF implants was significantly higher than that from SRF implants (p = 0.0002). Streptococcus species and Enterococcus faecalis were found to dominate. This in vivo study demonstrated bacterial colonization in both types of implant systems, irrespective of the type of connection. Significantly greater anaerobic counts were found in the Morse taper internal connection implants.

  19. Decontamination Efficiency of Fish Bacterial Flora from Processing Surfaces

    Directory of Open Access Journals (Sweden)

    Birna Guðbjörnsdóttir

    2009-01-01

    Full Text Available There are numerous parameters that can influence bacterial decontamination during washing of machinery and equipment in a food processing establishment. Incomplete decontamination of bacteria will increase the risk of biofilm formation and consequently increase the risk of pathogen contamination or prevalence of other undesirable microorganisms such as spoilage bacteria in the processing line. The efficiency of a typical washing protocol has been determined by testing three critical parameters and their effects on bacterial decontamination. Two surface materials (plastic and stainless steel, water temperatures (7 and 25 °C and detergent concentrations (2 and 4 % were used for this purpose in combination with two types of detergents. Biofilm was prepared on the surfaces with undefined bacterial flora obtained from minced cod fillets. The bacterial flora of the biofilm was characterised by cultivation and molecular analysis of 16S rRNA genes. All different combinations of washing protocols tested were able to remove more than 99.9 % of the bacteria in the biofilm and reduce the cell number from 7 to 0 or 2 log units of bacteria/cm2. The results show that it is possible to use less diluted detergents than recommended with comparable success, and it is easier to clean surface material made of stainless steel compared to polyethylene plastic.

  20. Surface display of proteins by Gram-negative bacterial autotransporters

    Directory of Open Access Journals (Sweden)

    Mourez Michael

    2006-06-01

    Full Text Available Abstract Expressing proteins of interest as fusions to proteins of the bacterial envelope is a powerful technique with many biotechnological and medical applications. Autotransporters have recently emerged as a good tool for bacterial surface display. These proteins are composed of an N-terminal signal peptide, followed by a passenger domain and a translocator domain that mediates the outer membrane translocation of the passenger. The natural passenger domain of autotransporters can be replaced by heterologous proteins that become displayed at the bacterial surface by the translocator domain. The simplicity and versatility of this system has made it very attractive and it has been used to display functional enzymes, vaccine antigens as well as polypeptides libraries. The recent advances in the study of the translocation mechanism of autotransporters have raised several controversial issues with implications for their use as display systems. These issues include the requirement for the displayed polypeptides to remain in a translocation-competent state in the periplasm, the requirement for specific signal sequences and "autochaperone" domains, and the influence of the genetic background of the expression host strain. It is therefore important to better understand the mechanism of translocation of autotransporters in order to employ them to their full potential. This review will focus on the recent advances in the study of the translocation mechanism of autotransporters and describe practical considerations regarding their use for bacterial surface display.

  1. An ortholog of the Leptospira interrogans lipoprotein LipL32 aids in the colonization of Pseudoalteromonas tunicata to host surfaces

    Directory of Open Access Journals (Sweden)

    Melissa eGardiner

    2014-07-01

    Full Text Available The bacterium P. tunicata is a common surface colonizer of marine eukaryotes, including the macroalga Ulva australis. Genomic analysis of P. tunicata identified genes potentially involved in surface colonization, including genes with homology to bacterial virulence factors that mediate attachment. Of particular interest is the presence of a gene, designated ptlL32, encoding an ortholog to the Leptospira lipoprotein LipL32, which has been shown to facilitate the interaction of Leptospira sp. with host extracellular matrix (ECM structures and is thought to be an important virulence trait for pathogenic Leptospira. To investigate the role of PtlL32 in the colonization by P. tunicata we constructed and characterized a ΔptlL32 mutant strain. Whilst P. tunicata ΔptlL32 bound to an abiotic surface with the same capacity as the wild type strain, it had a marked effect on the ability of P. tunicata to bind to ECM, suggesting a specific role in attachment to biological surfaces. Loss of PtlL32 also significantly reduced the capacity for P. tunciata to colonize the host algal surface demonstrating a clear role for this protein as a host-colonization factor. PtlL32 appears to have a patchy distribution across specific groups of environmental bacteria and phylogenetic analysis of PtlL32 orthologous proteins from non-Leptospira species suggests it may have been acquired via horizontal gene transfer between distantly related lineages. This study provides the first evidence for an attachment function for a LipL32- like protein outside the Leptospira and thereby contributes to the understanding of host colonization in ecologically distinct bacterial species.

  2. Bacterial growth on a superhydrophobic surface containing silver nanoparticles

    Science.gov (United States)

    Heinonen, S.; Nikkanen, J.-P.; Laakso, J.; Raulio, M.; Priha, O.; Levänen, E.

    2013-12-01

    The antibacterial effect of silver can be exploited in the food and beverage industry and medicinal applications to reduce biofouling of surfaces. Very small amount of silver ions are enough to destructively affect the metabolism of bacteria. Moreover, superhydrophobic properties could reduce bacterial adhesion to the surface. In this study we fabricated superhydrophobic surfaces that contained nanosized silver particles. The superhydrophobic surfaces were manufactured onto stainless steel as combination of ceramic nanotopography and hydrophobication by fluorosilane. Silver nanoparticles were precipitated onto the surface by a chemical method. The dissolution of silver from the surface was tested in an aqueous environment under pH values of 1, 3, 5, 7, 9, 11 and 13. The pH value was adjusted with nitric acid and ammonia. It was found that dissolution rate of silver increased as the pH of the solution altered from the pH of de-ionized water to lower and higher pH values but dissolution occurred also in de-ionized water. The antimicrobial potential of this coating was investigated using bacterial strains isolated from the brewery equipment surfaces. The results showed that the number of bacteria adhering onto steel surface was significantly reduced (88%) on the superhydrophobic silver containing coating.

  3. Early Administration of Probiotics Alters Bacterial Colonization and Limits Diet-Induced Gut Dysfunction and Severity of Necrotizing Enterocolitis in Preterm Pigs

    DEFF Research Database (Denmark)

    Siggers, Richard H.; Siggers, Jayda; Boye, Mette

    2008-01-01

    Following preterm birth, bacterial colonization and interal formula feeding predispose neonates to gut dysfunction and necrotizing enterocilitis (NEC), a serious gastrointestinal inflammatory disease. We hypothesized that administration of probiotics would beneficially influence early bacterial...... colonization, thereby reducing the susceptibility to formula-induced gut atrophy, dysfunction, and NEC. Caesarean-delivered preterm pigs were provided total parenteral nutrition (1.5 d) followed by enteral feeding (2d) with porcine colosstrum (COLOS; n= 5), formula (FORM; n = 9), or formula with probiotics...

  4. Development of the right colon and the peritoneal surface during the human fetal period: human ontogeny of the right colon.

    Science.gov (United States)

    Rigoard, Philippe; Haustein, Silke V; Doucet, Carole; Scepi, Michel; Richer, Jean Pierre; Faure, Jean Pierre

    2009-10-01

    Development of the digestive tract during the human fetal period has been the subject of many studies, but there are no works that study the ontogeny of both the right colon and the peritoneum. Based on the dissections of adult male cadavers and human fetuses, the aim of this anatomical study was to demonstrate the rules of the morpho-functional group, consisting of the right colon and its peritoneum surface, in human ontogeny. The morphology of the right colon results from a rotational motion, inducting the migration of the cecum in the right iliac fossa and formation of the hepatic flexure. This intestinal migration is based on the axis of rotation of the spreading area of the colon at the ventral side of the lower pole of the right kidney, which becomes visible after the 17th week. Our different observations plead in favor of the peritoneal fusion theory. A few variations of this fusion can explain all the disorders in the position of the cecum-appendix that are encountered in current surgery, as well as the possibility of internal hernias.

  5. Estimation of algal colonization growth on mortar surface using a ...

    Indian Academy of Sciences (India)

    Thu-Hien Tran

    method can successfully capture the functional relationship between the algal colonization growth and its influencing factors with a satisfactory outcome (the coefficient of determination R2 .... be trained very fast since its training process requires solving only a set of linear equations. The LS-SVR's model establishment boils ...

  6. Recognition of lysozyme using surface imprinted bacterial cellulose nanofibers.

    Science.gov (United States)

    Saylan, Yeşeren; Tamahkar, Emel; Denizli, Adil

    2017-11-01

    Here, we developed the lysozyme imprinted bacterial cellulose (Lyz-MIP/BC) nanofibers via the surface imprinting strategy that was designed to recognize lysozyme. This study includes the molecular imprinting method onto the surface of bacterial cellulose nanofibers in the presence of lysozyme by metal ion coordination, as well as further characterizations methods FTIR, SEM and contact angle measurements. The maximum lysozyme adsorption capacity of Lyz-MIP/BC nanofibers was found to be 71 mg/g. The Lyz-MIP/BC nanofibers showed high selectivity for lysozyme towards bovine serum albumin and cytochrome c. Overall, the Lyz-MIP/BC nanofibers hold great potential for lysozyme recognition due to the high binding capacity, significant selectivity and excellent reusability.

  7. The Pseudomonas aeruginosa chemotaxis methyltransferase CheR1 impacts on bacterial surface sampling.

    Directory of Open Access Journals (Sweden)

    Juliane Schmidt

    Full Text Available The characterization of factors contributing to the formation and development of surface-associated bacterial communities known as biofilms has become an area of intense interest since biofilms have a major impact on human health, the environment and industry. Various studies have demonstrated that motility, including swimming, swarming and twitching, seems to play an important role in the surface colonization and establishment of structured biofilms. Thereby, the impact of chemotaxis on biofilm formation has been less intensively studied. Pseudomonas aeruginosa has a very complex chemosensory system with two Che systems implicated in flagella-mediated motility. In this study, we demonstrate that the chemotaxis protein CheR1 is a methyltransferase that binds S-adenosylmethionine and transfers a methyl group from this methyl donor to the chemoreceptor PctA, an activity which can be stimulated by the attractant serine but not by glutamine. We furthermore demonstrate that CheR1 does not only play a role in flagella-mediated chemotaxis but that its activity is essential for the formation and maintenance of bacterial biofilm structures. We propose a model in which motility and chemotaxis impact on initial attachment processes, dispersion and reattachment and increase the efficiency and frequency of surface sampling in P. aeruginosa.

  8. Surface zwitterionization: Effective method for preventing oral bacterial biofilm formation on hydroxyapatite surfaces

    Science.gov (United States)

    Lee, Myoungjin; Kim, Heejin; Seo, Jiae; Kang, Minji; Kang, Sunah; Jang, Joomyung; Lee, Yan; Seo, Ji-Hun

    2018-01-01

    In this study, we conducted surface zwitterionization of hydroxyapatite (HA) surfaces by immersing them in the zwitterionic polymer solutions to provide anti-bacterial properties to the HA surface. Three different monomers containing various zwitterionic groups, i.e., phosphorylcholine (PC), sulfobetaine (SB), and carboxybetaine (CB), were copolymerized with the methacrylic monomer containing a Ca2+-binding moiety, using the free radical polymerization method. As a control, functionalization of the copolymer containing the Ca2+-binding moiety was synthesized using a hydroxy group. The stable immobilization of the zwitterionic functional groups was confirmed by water contact angle analysis and X-ray photoelectron spectroscopy (XPS) measurement conducted after the sonication process. The zwitterionized HA surface showed significantly decreased protein adsorption, whereas the hydroxyl group-coated HA surface showed limited efficacy. The anti-bacterial adhesion property was confirmed by conducting Streptococcus mutans (S. mutans) adhesion tests for 6 h and 24 h. When furanone C-30, a representative anti-quorum sensing molecule for S. mutans, was used, only a small amount of bacteria adhered after 6 h and the population did not increase after 24 h. In contrast, zwitterionized HA surfaces showed almost no bacterial adhesion after 6 h and the effect was retained for 24 h, resulting in the lowest level of oral bacterial adhesion. These results confirm that surface zwitterionization is a promising method to effectively prevent oral bacterial adhesion on HA-based materials.

  9. Biocontrol of Bacterial Fruit Blotch byBacillus subtilis9407 via Surfactin-Mediated Antibacterial Activity and Colonization.

    Science.gov (United States)

    Fan, Haiyan; Zhang, Zhanwei; Li, Yan; Zhang, Xun; Duan, Yongming; Wang, Qi

    2017-01-01

    In this study, Bacillus subtilis 9407 showed a strong antibacterial activity against Acidovorax citrulli in vitro and 61.7% biocontrol efficacy on melon seedlings 4 days post inoculation under greenhouse conditions. To understand the biocontrol mechanism of B. subtilis 9407, identify the primary antibacterial compound and determine its role in controlling bacterial fruit blotch (BFB), a srfAB deletion mutant (Δ srfAB ) was constructed. The Δ srfAB which was deficient in production of surfactin, not only showed almost no ability to inhibit growth of A. citrulli but also decreased biofilm formation and reduced swarming motility. Colonization assay demonstrated that B. subtilis 9407 could conlonize on melon roots and leaves in a large population, while Δ srfAB showed a four- to ten-fold reduction in colonization of melon roots and leaves. Furthermore, a biocontrol assay showed that Δ srfAB lost the biocontrol efficacy. In summary, our results indicated that surfactin, which consists of C13- to C16-surfactin A was the primary antibacterial compound of B. subtilis 9407, and it played a major role in biofilm formation, swarming motility, colonization and suppressing BFB. We propose that the biocontrol activity of B. subtilis 9407 is the results of the coordinated action of surfactin-mediated antibacterial activity and colonization. This study reveals for the first time that the use of a B. subtilis strain as a potential biological control agent could efficiently control BFB by producing surfactin.

  10. Colonization and Maize Growth Promotion Induced by Phosphate Solubilizing Bacterial Isolates.

    Science.gov (United States)

    Li, Yongbin; Liu, Xiaomeng; Hao, Tianyi; Chen, Sanfeng

    2017-06-29

    Phosphorus (P) limits the production of maize, one of the major food crops in China. Phosphate-solubilizing bacteria (PSB) have the capacity to solubilize phosphate complexes into plant absorbable and utilizable forms by the process of acidification, chelation, and exchange reactions. In this study, six bacteria, including one Paenibacillus sp. B1 strain, four Pseudomonas sp. strains (B10, B14, SX1, and SX2) and one Sphingobium sp. SX14 strain, were those isolated from the maize rhizosphere and identified based on their 16S rRNA sequences. All strains could solubilize inorganic P (Ca₃(PO₄)₂, FePO₄ and AlPO₄), and only B1 and B10 organic P (lecithin). All strains, except of SX1, produced IAA, and SX14 and B1 showed the highest level. B1 incited the highest increase in root length and the second increase in shoot and total dry weight, shoot length, and total P and nitrogen (N), along with increased root length. In addition, by confocal laser scanning microscopy (CLSM), we found that green fluorescent protein (GFP)-labeled B1 mainly colonized root surfaces and in epidermal and cortical tissue. Importantly, B1 can survive through forming spores under adverse conditions and prolong quality guarantee period of bio-fertilizer. Therefore, it can act as a good substitute for bio-fertilizer to promote agricultural sustainability.

  11. Analysis of bacterial-surface-specific antibodies in body fluids using bacterial flow cytometry.

    Science.gov (United States)

    Moor, Kathrin; Fadlallah, Jehane; Toska, Albulena; Sterlin, Delphine; Balmer, Maria L; Macpherson, Andrew J; Gorochov, Guy; Larsen, Martin; Slack, Emma

    2016-08-01

    Antibacterial antibody responses that target surfaces of live bacteria or secreted toxins are likely to be relevant in controlling bacterial pathogenesis. The ability to specifically quantify bacterial-surface-binding antibodies is therefore highly attractive as a quantitative correlate of immune protection. Here, binding of antibodies from various body fluids to pure-cultured live bacteria is made visible with fluorophore-conjugated secondary antibodies and measured by flow cytometry. We indicate the necessary controls for excluding nonspecific binding and also demonstrate a cross-adsorption technique for determining the extent of cross-reactivity. This technique has numerous advantages over standard ELISA and western blotting techniques because of its independence from scaffold binding, exclusion of cross-reactive elements from lysed bacteria and ability to visualize bacterial subpopulations. In addition, less than 10(5) bacteria and less than 10 μg of antibody are required per sample. The technique requires 3-4 h of hands-on experimentation and analysis. Moreover, it can be combined with automation and mutliplexing for high-throughput applications.

  12. The bacterial cytoskeleton modulates motility, type 3 secretion, and colonization in Salmonella.

    Directory of Open Access Journals (Sweden)

    David M Bulmer

    2012-01-01

    Full Text Available Although there have been great advances in our understanding of the bacterial cytoskeleton, major gaps remain in our knowledge of its importance to virulence. In this study we have explored the contribution of the bacterial cytoskeleton to the ability of Salmonella to express and assemble virulence factors and cause disease. The bacterial actin-like protein MreB polymerises into helical filaments and interacts with other cytoskeletal elements including MreC to control cell-shape. As mreB appears to be an essential gene, we have constructed a viable ΔmreC depletion mutant in Salmonella. Using a broad range of independent biochemical, fluorescence and phenotypic screens we provide evidence that the Salmonella pathogenicity island-1 type three secretion system (SPI1-T3SS and flagella systems are down-regulated in the absence of MreC. In contrast the SPI-2 T3SS appears to remain functional. The phenotypes have been further validated using a chemical genetic approach to disrupt the functionality of MreB. Although the fitness of ΔmreC is reduced in vivo, we observed that this defect does not completely abrogate the ability of Salmonella to cause disease systemically. By forcing on expression of flagella and SPI-1 T3SS in trans with the master regulators FlhDC and HilA, it is clear that the cytoskeleton is dispensable for the assembly of these structures but essential for their expression. As two-component systems are involved in sensing and adapting to environmental and cell surface signals, we have constructed and screened a panel of such mutants and identified the sensor kinase RcsC as a key phenotypic regulator in ΔmreC. Further genetic analysis revealed the importance of the Rcs two-component system in modulating the expression of these virulence factors. Collectively, these results suggest that expression of virulence genes might be directly coordinated with cytoskeletal integrity, and this regulation is mediated by the two-component system

  13. Anhydride-functional silane immobilized onto titanium surfaces induces osteoblast cell differentiation and reduces bacterial adhesion and biofilm formation

    Energy Technology Data Exchange (ETDEWEB)

    Godoy-Gallardo, Maria, E-mail: maria.godoy.gallardo@upc.edu [Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC), ETSEIB, Av. Diagonal 647, 08028 Barcelona (Spain); Centre for Research in NanoEngineering (CRNE) — UPC, C/ Pascual i Vila 15, 08028 Barcelona (Spain); Guillem-Marti, Jordi, E-mail: jordi.guillem.marti@upc.edu [Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC), ETSEIB, Av. Diagonal 647, 08028 Barcelona (Spain); Centre for Research in NanoEngineering (CRNE) — UPC, C/ Pascual i Vila 15, 08028 Barcelona (Spain); Sevilla, Pablo, E-mail: psevilla@euss.es [Department of Mechanics, Escola Universitària Salesiana de Sarrià (EUSS), C/ Passeig de Sant Bosco, 42, 08017 Barcelona (Spain); Manero, José M., E-mail: jose.maria.manero@upc.edu [Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC), ETSEIB, Av. Diagonal 647, 08028 Barcelona (Spain); Centre for Research in NanoEngineering (CRNE) — UPC, C/ Pascual i Vila 15, 08028 Barcelona (Spain); Gil, Francisco J., E-mail: francesc.xavier.gil@upc.edu [Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC), ETSEIB, Av. Diagonal 647, 08028 Barcelona (Spain); Centre for Research in NanoEngineering (CRNE) — UPC, C/ Pascual i Vila 15, 08028 Barcelona (Spain); and others

    2016-02-01

    Bacterial infection in dental implants along with osseointegration failure usually leads to loss of the device. Bioactive molecules with antibacterial properties can be attached to titanium surfaces with anchoring molecules such as silanes, preventing biofilm formation and improving osseointegration. Properties of silanes as molecular binders have been thoroughly studied, but research on the biological effects of these coatings is scarce. The aim of the present study was to determine the in vitro cell response and antibacterial effects of triethoxysilypropyl succinic anhydride (TESPSA) silane anchored on titanium surfaces. X-ray photoelectron spectroscopy confirmed a successful silanization. The silanized surfaces showed no cytotoxic effects. Gene expression analyses of Sarcoma Osteogenic (SaOS-2) osteoblast-like cells cultured on TESPSA silanized surfaces reported a remarkable increase of biochemical markers related to induction of osteoblastic cell differentiation. A manifest decrease of bacterial adhesion and biofilm formation at early stages was observed on treated substrates, while favoring cell adhesion and spreading in bacteria–cell co-cultures. Surfaces treated with TESPSA could enhance a biological sealing on implant surfaces against bacteria colonization of underlying tissues. Furthermore, it can be an effective anchoring platform of biomolecules on titanium surfaces with improved osteoblastic differentiation and antibacterial properties. - Highlights: • TESPSA silane induces osteoblast differentiation. • TESPSA reduces bacterial adhesion and biofilm formation. • TESPSA is a promising anchoring platform of biomolecules onto titanium.

  14. Surface physicochemical properties at the micro and nano length scales: role on bacterial adhesion and Xylella fastidiosa biofilm development.

    Science.gov (United States)

    Lorite, Gabriela S; Janissen, Richard; Clerici, João H; Rodrigues, Carolina M; Tomaz, Juarez P; Mizaikoff, Boris; Kranz, Christine; de Souza, Alessandra A; Cotta, Mônica A

    2013-01-01

    The phytopathogen Xylella fastidiosa grows as a biofilm causing vascular occlusion and consequently nutrient and water stress in different plant hosts by adhesion on xylem vessel surfaces composed of cellulose, hemicellulose, pectin and proteins. Understanding the factors which influence bacterial adhesion and biofilm development is a key issue in identifying mechanisms for preventing biofilm formation in infected plants. In this study, we show that X. fastidiosa biofilm development and architecture correlate well with physicochemical surface properties after interaction with the culture medium. Different biotic and abiotic substrates such as silicon (Si) and derivatized cellulose films were studied. Both biofilms and substrates were characterized at the micro- and nanoscale, which corresponds to the actual bacterial cell and membrane/ protein length scales, respectively. Our experimental results clearly indicate that the presence of surfaces with different chemical composition affect X. fastidiosa behavior from the point of view of gene expression and adhesion functionality. Bacterial adhesion is facilitated on more hydrophilic surfaces with higher surface potentials; XadA1 adhesin reveals different strengths of interaction on these surfaces. Nonetheless, despite different architectural biofilm geometries and rates of development, the colonization process occurs on all investigated surfaces. Our results univocally support the hypothesis that different adhesion mechanisms are active along the biofilm life cycle representing an adaptation mechanism for variations on the specific xylem vessel composition, which the bacterium encounters within the infected plant.

  15. Anhydride-functional silane immobilized onto titanium surfaces induces osteoblast cell differentiation and reduces bacterial adhesion and biofilm formation

    International Nuclear Information System (INIS)

    Godoy-Gallardo, Maria; Guillem-Marti, Jordi; Sevilla, Pablo; Manero, José M.; Gil, Francisco J.

    2016-01-01

    Bacterial infection in dental implants along with osseointegration failure usually leads to loss of the device. Bioactive molecules with antibacterial properties can be attached to titanium surfaces with anchoring molecules such as silanes, preventing biofilm formation and improving osseointegration. Properties of silanes as molecular binders have been thoroughly studied, but research on the biological effects of these coatings is scarce. The aim of the present study was to determine the in vitro cell response and antibacterial effects of triethoxysilypropyl succinic anhydride (TESPSA) silane anchored on titanium surfaces. X-ray photoelectron spectroscopy confirmed a successful silanization. The silanized surfaces showed no cytotoxic effects. Gene expression analyses of Sarcoma Osteogenic (SaOS-2) osteoblast-like cells cultured on TESPSA silanized surfaces reported a remarkable increase of biochemical markers related to induction of osteoblastic cell differentiation. A manifest decrease of bacterial adhesion and biofilm formation at early stages was observed on treated substrates, while favoring cell adhesion and spreading in bacteria–cell co-cultures. Surfaces treated with TESPSA could enhance a biological sealing on implant surfaces against bacteria colonization of underlying tissues. Furthermore, it can be an effective anchoring platform of biomolecules on titanium surfaces with improved osteoblastic differentiation and antibacterial properties. - Highlights: • TESPSA silane induces osteoblast differentiation. • TESPSA reduces bacterial adhesion and biofilm formation. • TESPSA is a promising anchoring platform of biomolecules onto titanium.

  16. Dandruff is associated with disequilibrium in the proportion of the major bacterial and fungal populations colonizing the scalp.

    Directory of Open Access Journals (Sweden)

    Cécile Clavaud

    Full Text Available The bacterial and fungal communities associated with dandruff were investigated using culture-independent methodologies in the French subjects. The major bacterial and fungal species inhabiting the scalp subject's were identified by cloning and sequencing of the conserved ribosomal unit regions (16S for bacterial and 28S-ITS for fungal and were further quantified by quantitative PCR. The two main bacterial species found on the scalp surface were Propionibacterium acnes and Staphylococcus epidermidis, while Malassezia restricta was the main fungal inhabitant. Dandruff was correlated with a higher incidence of M. restricta and S. epidermidis and a lower incidence of P. acnes compared to the control population (p<0.05. These results suggested for the first time using molecular methods, that dandruff is linked to the balance between bacteria and fungi of the host scalp surface.

  17. Studying the Differences of Bacterial Metabolome and Microbiome in the Colon between Landrace and Meihua Piglets

    Directory of Open Access Journals (Sweden)

    Shijuan Yan

    2017-09-01

    Full Text Available This study was conducted to compare the microbiome and metabolome differences in the colon lumen from two pig breeds with different genetic backgrounds. Fourteen weaned piglets at 30 days of age, including seven Landrace piglets (a lean-type pig breed with a fast growth rate and seven Meihua piglets (a fatty-type Chinese local pig breed with a slow growth rate, were fed the same diets for 35 days. Untargeted metabolomics analyses showed that a total of 401 metabolites differed between Landrace and Meihua. Seventy of these 401 metabolites were conclusively identified. Landrace accumulated more short-chain fatty acids (SCFAs and secondary bile acids in the colon lumen. Moreover, expression of the SCFAs transporter (solute carrier family 5 member 8, SLC5A8 and receptor (G protein-coupled receptor 41, GPR41 in the colon mucosa was higher, while the bile acids receptor (farnesoid X receptor, FXR had lower expression in Landrace compared to Meihua. The relative abundances of 8 genera and 16 species of bacteria differed significantly between Landrace and Meihua, and were closely related to the colonic concentrations of bile acids or SCFAs based on Pearson's correlation analysis. Collectively, our results demonstrate for the first time that there were differences in the colonic microbiome and metabolome between Meihua and Landrace piglets, with the most profound disparity in production of SCFAs and secondary bile acids.

  18. Nature of bacterial colonization influences transcription of mucin genes in mice during the first week of life

    Directory of Open Access Journals (Sweden)

    Bergström Anders

    2012-08-01

    Full Text Available Abstract Background Postnatal regulation of the small intestinal mucus layer is potentially important in the development of adult gut functionality. We hypothesized that the nature of bacterial colonization affects mucus gene regulation in early life. We thus analyzed the influence of the presence of a conventional microbiota as well as two selected monocolonizing bacterial strains on the transcription of murine genes involved in mucus layer development during the first week of life. Mouse pups (N = 8/group from differently colonized dams: Germ-free (GF, conventional specific pathogen free (SPF, monocolonized with either Lactobacillus acidophilus NCFM (Lb or Escherichia coli Nissle (Ec were analyzed by qPCR on isolated ileal tissue sections from postnatal days 1 and 6 (PND1, PND6 after birth with respect to: (i transcription of specific genes involved in mucus production (Muc1-4, Tff3 and (ii amounts of 16S rRNA of Lactobacillus and E. coli. Quantification of 16S rRNA genes was performed to obtain a measure for amounts of colonized bacteria. Results We found a microbiota-independent transcriptional increase of all five mucus genes from PND1 to PND6. Furthermore, the relative level of transcription of certain mucus genes on PND1 was increased by the presence of bacteria. This was observed for Tff3 in the SPF, Ec, and Lb groups; for Muc2 in SPF; and for Muc3 and Muc4 in Ec and Lb, respectively. Detection of bacterial 16S rRNA genes levels above the qPCR detection level occurred only on PND6 and only for some of the colonized animals. On PND6, we found significantly lower levels of Muc1, Muc2 and Muc4 gene transcription for Lb animals with detectable Lactobacillus levels as compared to animals with Lactobacillus levels below the detection limit. Conclusions In summary, our data show that development of the expression of genes encoding secreted (Muc2/Tff3 and membrane-bound (Muc1/Muc3/Muc4 mucus regulatory proteins, respectively, is distinct and

  19. Xylo-Oligosaccharides and Inulin Affect Genotoxicity and Bacterial Populations Differently in a Human Colonic Simulator Challenged with Soy Protein

    Directory of Open Access Journals (Sweden)

    Michael A. Conlon

    2013-09-01

    Full Text Available High dietary intakes of some protein sources, including soy protein, can increase colonic DNA damage in animals, whereas some carbohydrates attenuate this. We investigated whether inulin and xylo-oligosaccharides (XOS could be protective against DNA strand breaks by adding them to a human colonic simulator consisting of a proximal vessel (PV (pH 5.5 and a distal vessel (DV (pH 6.8 inoculated with human faeces and media containing soy protein. Genotoxicity of the liquid phase and microbial population changes in the vessels were measured. Soy protein (3% was fermented with 1% low amylose cornstarch for 10 day followed by soy protein with 1% XOS or 1% inulin for 10 day. Inulin did not alter genotoxicity but XOS significantly reduced PV genotoxicity and increased DV genotoxicity. Inulin and XOS significantly increased butyrate concentration in the DV but not PV. Numbers of the key butyrate-producing bacterium Faecalibacterium prausnitzii were significantly increased in the PV and DV by inulin but significantly decreased by XOS in both vessels. Other bacteria examined were also significantly impacted by the carbohydrate treatments or by the vessel (i.e., pH. There was a significant overall inverse correlation between levels of damage induced by the ferments and levels of sulphate-reducing bacteria, Bacteroides fragilis, and acetate. In conclusion, dietary XOS can potentially modulate the genotoxicity of the colonic environment and specific bacterial groups and short chain fatty acids may mediate this.

  20. Xylo-Oligosaccharides and Inulin Affect Genotoxicity and Bacterial Populations Differently in a Human Colonic Simulator Challenged with Soy Protein

    Science.gov (United States)

    Christophersen, Claus T.; Petersen, Anne; Licht, Tine R.; Conlon, Michael A.

    2013-01-01

    High dietary intakes of some protein sources, including soy protein, can increase colonic DNA damage in animals, whereas some carbohydrates attenuate this. We investigated whether inulin and xylo-oligosaccharides (XOS) could be protective against DNA strand breaks by adding them to a human colonic simulator consisting of a proximal vessel (PV) (pH 5.5) and a distal vessel (DV) (pH 6.8) inoculated with human faeces and media containing soy protein. Genotoxicity of the liquid phase and microbial population changes in the vessels were measured. Soy protein (3%) was fermented with 1% low amylose cornstarch for 10 day followed by soy protein with 1% XOS or 1% inulin for 10 day. Inulin did not alter genotoxicity but XOS significantly reduced PV genotoxicity and increased DV genotoxicity. Inulin and XOS significantly increased butyrate concentration in the DV but not PV. Numbers of the key butyrate-producing bacterium Faecalibacterium prausnitzii were significantly increased in the PV and DV by inulin but significantly decreased by XOS in both vessels. Other bacteria examined were also significantly impacted by the carbohydrate treatments or by the vessel (i.e., pH). There was a significant overall inverse correlation between levels of damage induced by the ferments and levels of sulphate-reducing bacteria, Bacteroides fragilis, and acetate. In conclusion, dietary XOS can potentially modulate the genotoxicity of the colonic environment and specific bacterial groups and short chain fatty acids may mediate this. PMID:24064573

  1. Bacterial colonization of the phyllosphere of mediterranean perennial species as influenced by leaf structural and chemical features.

    Science.gov (United States)

    Yadav, R K P; Karamanoli, K; Vokou, D

    2005-08-01

    In this study, we assessed various leaf structural and chemical features as possible predictors of the size of the phyllosphere bacterial population in the Mediterranean environment. We examined eight perennial species, naturally occurring and coexisting in the same area, in Halkidiki (northern Greece). They are Arbutus unedo, Quercus coccifera, Pistacia lentiscus, and Myrtus communis (evergreen sclerophyllous species), Lavandula stoechas and Cistus incanus (drought semi-deciduous species), and Calamintha nepeta and Melissa officinalis (non-woody perennial species). M. communis, L. stoechas, C. nepeta, and M. officinalis produce essential oil in substantial quantities. We sampled summer leaves from these species and (1) estimated the size of the bacterial population of their phyllosphere, (2) estimated the concentration of different leaf constituents, and (3) studied leaf morphological and anatomical features and expressed them in a quantitative way. The aromatic plants are on average more highly colonized than the other species, whereas the non-woody perennials are more highly colonized than the woody species. The population size of epiphytic bacteria is positively correlated with glandular and non-glandular trichome densities, and with water and phosphorus contents; it is negatively correlated with total phenolics content and the thickness of the leaf, of the mesophyll, and of the abaxial epidermis. No correlation was found with the density of stomata, the nitrogen, and the soluble sugar contents. By regression tree analysis, we found that the leaf-microbe system can be effectively described by three leaf attributes with leaf water content being the primary explanatory attribute. Leaves with water content >73% are the most highly colonized. For leaves with water content 1.34 mg g(-1) d.w.) are more colonized, and leaves with the adaxial epidermis thicker than 20.77 microm are the least colonized. Although these critical attributes and values hold true only within

  2. Diversity of bacterial communities that colonize the filter units used for controlling plant pathogens in soilless cultures.

    Science.gov (United States)

    Renault, David; Vallance, Jessica; Déniel, Franck; Wery, Nathalie; Godon, Jean Jacques; Barbier, Georges; Rey, Patrice

    2012-01-01

    In recent years, increasing the level of suppressiveness by the addition of antagonistic bacteria in slow filters has become a promising strategy to control plant pathogens in the recycled solutions used in soilless cultures. However, knowledge about the microflora that colonize the filtering columns is still limited. In order to get information on this issue, the present study was carried out over a 4-year period and includes filters inoculated or not with suppressive bacteria at the start of the filtering process (two or three filters were used each year). After 9 months of filtration, polymerase chain reaction (PCR)-single strand conformation polymorphism analyses point out that, for the same year of experiment, the bacterial communities from control filters were relatively similar but that they were significantly different between the bacteria-amended and control filters. To characterize the changes in bacterial communities within the filters, this microflora was studied by quantitative PCR, community-level physiological profiles, and sequencing 16SrRNA clone libraries (filters used in year 1). Quantitative PCR evidenced a denser bacterial colonization of the P-filter (amended with Pseudomonas putida strains) than control and B-filter (amended with Bacillus cereus strains). Functional analysis focused on the cultivable bacterial communities pointed out that bacteria from the control filter metabolized more carbohydrates than those from the amended filters whose trophic behaviors were more targeted towards carboxylic acids and amino acids. The bacterial communities in P- and B-filters both exhibited significantly more phylotype diversity and markedly distinct phylogenetic compositions than those in the C-filter. Although there were far fewer Proteobacteria in B- and P-filters than in the C-filter (22% and 22% rather than 69% of sequences, respectively), the percentages of Firmicutes was much higher (44% and 55% against 9%, respectively). Many Pseudomonas

  3. Neonatal Bacterial Colonization Predispose to Lower Respiratory Infections in Early Childhood

    DEFF Research Database (Denmark)

    Vissing, Nadja Hawwa

    2014-01-01

    , the variation has been explained by environmental exposures such as day care attendance, breastfeeding, crowding, siblings, tobacco smoke exposure, low socioeconomic status, and male sex, but these risk factors only explain a minor proportion of the variation. Confidence in the results is hampered by lack...... neonatal airway colonization and risk of the LRI in a validated study cohort, and whether a possible association could be reflected in the early immune response to airway pathogens. In study I we aimed to ascertain the quality of information on child’s health, including asthma, allergy, eczema, respiratory...... at 4 weeks of age, revealing that 21% of the healthy neonates were colonized with Streptococcus pneumoniae, Hemofilus influenzae and/or Moraxella catarrhalis. Colonization with at least one of these microorganisms was significantly associated with two-fold increased incidence of LRI, independently...

  4. Ternary Complexation on Bacterial Surfaces: Implications for Subsurface Anion Transport

    Science.gov (United States)

    Maclean, L. C.; Higginbottom, C. M.; Fowle, D. A.

    2002-12-01

    The physical, chemical, and biological controls on contaminant mobilities in aquatic ecosystems must be determined to establish the threat that contamination poses to the environment. Quantitative models of contaminant mobilities are required as a prerequisite to guide remediation efforts and to prioritize the potential hazard to the ecosystem of each contaminated site. It is well established that mineral surface adsorption is an important control on contaminant mobilities, and many studies have utilized thermodynamics to quantify metal/organic adsorption in order to yield predictive models of contaminant transport. However, these models of contaminant transport may not be representative of the reactions which control contaminant mobilities as most mineral surfaces are coated with organic acids, bacteria, and extracellular polymers. Numerous laboratory studies have demonstrated that bacterial cell walls have a high affinity for binding metal cations, and field studies indicate that a significant proportion of bacteria cells and associated extracellular matrices are coated with small scale hydrous metal oxides. The small size of bacteria, and in many cases the nanoscale of their associated mineral phases, suggests these bacteria-mineral composites may represent a large proportion of surface area exposed to fluid flow. Therefore, due to the affinity of bacterial cell walls for cations and biominerals, bacteria may also have a significant impact on anionic contaminant mobility in many natural systems. The extent of metal-bacteria adsorption reactions varies drastically as a function of pH and solution chemistry. Current adsorption models have focused on the interactions of positively charged metal cations with bacterial surfaces, however in many oxidizing environments metals such as Cr exist as anions or anionic complexes. We have studied the ability of non-metabolizing cells of the bacterial species Bacillus subtilis and Shewanella putrifaciens to adsorb aqueous Cr

  5. Biocontrol of verticillium wilt and colonization of cotton plants by an endophytic bacterial isolate.

    Science.gov (United States)

    Li, C-H; Shi, L; Han, Q; Hu, H-L; Zhao, M-W; Tang, C-M; Li, S-P

    2012-09-01

    To explore biocontrol potential of 39 DAEB isolates (doubly antagonistic towards both Verticillium dahliae Kleb and Fusarium oxysporum) against verticillium wilt of cotton and to elucidate colonization and category characteristics of an endophytic bacterium with significant biocontrol activity. Thirty-nine antagonistic endophytic bacteria strains were tested for their ability to control verticillium wilt in cotton plants caused by a defoliating pathotype of V. dahliae 107 in cotton under controlled conditions. The biocontrol trial revealed that an endophytic bacterium, designated HA02, showed a significant biocontrol activity to V. dahliae 107. After cotton seedlings were inoculated with a gfp gene-tagged HA02 (HA02-gfp), HA02-gfp populations were higher in the root than in the stem; in addition, the HA02-gfp was distributed in the maturation zone of cotton root. Furthermore, HA02-gfp also colonized seedlings of maize, rape and soybean after the bacteria inoculation. Phylogenetic trees based on 16S rDNA sequences combined with morphological, physiological and identification showed that the bacterium belongs to the Enterobacter genus. Our results showed that only 1 of 39 DAEB isolates demonstrated more efficient biocontrol potential towards V. dahliae 107 in greenhouse and field trials. HA02-gfp mainly colonized cotton in roots. In addition, we quantitatively observed HA02 colonization in other hosts. HA02 belongs to the Enterobacter genus. This is the first study on biocontrol to defoliating pathotype of V. dahliae Kleb by endophytic bacteria. The HA02 showed effective biocontrol to V. dahliae 107 in greenhouse and field trials. Furthermore, we assessed the quantitative and qualitative colonization of HA02 in cotton seedlings. Our study provides basic information to further explore managing strategies to control this critical disease. © 2012 The Authors Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

  6. Surface Proteins of Lactococcus lactis: Bacterial Resources for Muco-adhesion in the Gastrointestinal Tract

    Directory of Open Access Journals (Sweden)

    Muriel Mercier-Bonin

    2017-11-01

    Full Text Available Food and probiotic bacteria, in particular lactic acid bacteria, are ingested in large amounts by humans and are part of the transient microbiota which is increasingly considered to be able to impact the resident microbiota and thus possibly the host health. The lactic acid bacterium Lactococcus lactis is extensively used in starter cultures to produce dairy fermented food. Also because of a generally recognized as safe status, L. lactis has been considered as a possible vehicle to deliver in vivo therapeutic molecules with anti-inflammatory properties in the gastrointestinal tract. One of the key factors that may favor health effects of beneficial bacteria to the host is their capacity to colonize transiently the gut, notably through close interactions with mucus, which covers and protects the intestinal epithelium. Several L. lactis strains have been shown to exhibit mucus-binding properties and bacterial surface proteins have been identified as key determinants of such capacity. In this review, we describe the different types of surface proteins found in L. lactis, with a special focus on mucus-binding proteins and pili. We also review the different approaches used to investigate the adhesion of L. lactis to mucus, and particularly to mucins, one of its major components, and we present how these approaches allowed revealing the role of surface proteins in muco-adhesion.

  7. The mechanics of bacterial cluster formation on plant leaf surfaces as revealed by bioreporter technology

    NARCIS (Netherlands)

    Tecon, R.; Leveau, J.H.J.

    2012-01-01

    Bacteria that colonize the leaves of terrestrial plants often occur in clusters whose size varies from a few to thousands of cells. For the formation of such bacterial clusters, two non-mutually exclusive but very different mechanisms may be proposed: aggregation of multiple cells or clonal

  8. The effects of the time of intranasal splinting on bacterial colonization, postoperative complications, and patient discomfort after septoplasty operations.

    Science.gov (United States)

    Karatas, Abdullah; Pehlivanoglu, Filiz; Salviz, Mehti; Kuvat, Nuray; Cebi, Isil Taylan; Dikmen, Burak; Sengoz, Gonul

    The main reason for nasal tampon placement after septoplasty is to prevent postoperative hemorrhage, while the secondary purpose is internal stabilization after operations involving the cartilaginous-bony skeleton of the nose. Silicone intranasal splints are as successful as other materials in controlling postoperative hemorrhages of septal origin. The possibility of leaving the splints intranasally for extended periods helps stabilize the septum in the midline. However, there is nothing in the literature about how long these splints can be retained inside the nasal cavity without increasing the risk of infection, postoperative complications, and patient discomfort. The current study aimed to evaluate the association between the duration of intranasal splinting and bacterial colonization, postoperative complications, and patient discomfort. Patients who had undergone septoplasty were divided into three groups according to the day of removal of the silicone splints. The splints were removed on the fifth, seventh, and tenth postoperative days. The removed splints were microbiologically cultured. Early and late complications were assessed, including local and systemic infections, tissue necrosis, granuloma formation, mucosal crusting, synechia, and septal perforation. Postoperative patient discomfort was evaluated by scoring the levels of pain and nasal obstruction. No significant difference was found in the rate of bacterial colonization among the different groups. Decreased mucosal crusting and synechia were detected with longer usage intervals of intranasal silicone splints. Postoperative pain and nasal obstruction were also diminished by the third postoperative day. Silicone splints were well tolerated by the patients and any negative effects on postoperative patient comfort were limited. In fact, prolonged splint usage intervals reduced late complications. Long-term silicone nasal splint usage is a reliable, effective, and comfortable method in patients with

  9. The effects of the time of intranasal splinting on bacterial colonization, postoperative complications, and patient discomfort after septoplasty operations

    Directory of Open Access Journals (Sweden)

    Abdullah Karatas

    Full Text Available Abstract Introduction: The main reason for nasal tampon placement after septoplasty is to prevent postoperative hemorrhage, while the secondary purpose is internal stabilization after operations involving the cartilaginous-bony skeleton of the nose. Silicone intranasal splints are as successful as other materials in controlling postoperative hemorrhages of septal origin. The possibility of leaving the splints intranasally for extended periods helps stabilize the septum in the midline. However, there is nothing in the literature about how long these splints can be retained inside the nasal cavity without increasing the risk of infection, postoperative complications, and patient discomfort. Objective: The current study aimed to evaluate the association between the duration of intranasal splinting and bacterial colonization, postoperative complications, and patient discomfort. Methods: Patients who had undergone septoplasty were divided into three groups according to the day of removal of the silicone splints. The splints were removed on the fifth, seventh, and tenth postoperative days. The removed splints were microbiologically cultured. Early and late complications were assessed, including local and systemic infections, tissue necrosis, granuloma formation, mucosal crusting, synechia, and septal perforation. Postoperative patient discomfort was evaluated by scoring the levels of pain and nasal obstruction. Results: No significant difference was found in the rate of bacterial colonization among the different groups. Decreased mucosal crusting and synechia were detected with longer usage intervals of intranasal silicone splints. Postoperative pain and nasal obstruction were also diminished by the third postoperative day. Conclusions: Silicone splints were well tolerated by the patients and any negative effects on postoperative patient comfort were limited. In fact, prolonged splint usage intervals reduced late complications. Long-term silicone

  10. Colonization of Vitis vinifera by a green fluorescence protein-labeled, gfp-marked strain of Xylophilus ampelinus, the causal agent of bacterial necrosis of grapevine.

    Science.gov (United States)

    Grall, Sophie; Manceau, Charles

    2003-04-01

    The dynamics of Xylophilus ampelinus were studied in Vitis vinifera cv. Ugni blanc using gfp-marked bacterial strains to evaluate the relative importance of epiphytic and endophytic phases of plant colonization in disease development. Currently, bacterial necrosis of grapevine is of economic importance in vineyards in three regions in France: the Cognac, Armagnac, and Die areas. This disease is responsible for progressive destruction of vine shoots, leading to their death. We constructed gfp-marked strains of the CFBP2098 strain of X. ampelinus for histological studies. We studied the colonization of young plants of V. vinifera cv. Ugni blanc by X. ampelinus after three types of artificial contamination in a growth chamber and in a greenhouse. (i) After wounding of the stem and inoculation, the bacteria progressed down to the crown through the xylem vessels, where they organized into biofilms. (ii) When the bacteria were forced into woody cuttings, they rarely colonized the emerging plantlets. Xylem vessels could play a key role in the multiplication and conservation of the bacteria, rather than being a route for plant colonization. (iii) When bacterial suspensions were sprayed onto the plants, bacteria progressed in two directions: both in emerging organs and down to the crown, thus displaying the importance of epiphytic colonization in disease development.

  11. Impact of Bacterial-Fungal Interactions on the Colonization of the Endosphere

    NARCIS (Netherlands)

    Overbeek, van L.S.; Saikkonen, Kari

    2016-01-01

    Research on different endophyte taxa and the related scientific disciplines have largely developed separately, and comprehensive community-level studies on bacterial and fungal interactions and their importance are lacking. Here, we discuss the transmission modes of bacteria and fungi and the

  12. Active Transport of Phosphorylated Carbohydrates Promotes Intestinal Colonization and Transmission of a Bacterial Pathogen.

    Directory of Open Access Journals (Sweden)

    Brandon Sit

    2015-08-01

    Full Text Available Efficient acquisition of extracellular nutrients is essential for bacterial pathogenesis, however the identities and mechanisms for transport of many of these substrates remain unclear. Here, we investigate the predicted iron-binding transporter AfuABC and its role in bacterial pathogenesis in vivo. By crystallographic, biophysical and in vivo approaches, we show that AfuABC is in fact a cyclic hexose/heptose-phosphate transporter with high selectivity and specificity for a set of ubiquitous metabolites (glucose-6-phosphate, fructose-6-phosphate and sedoheptulose-7-phosphate. AfuABC is conserved across a wide range of bacterial genera, including the enteric pathogens EHEC O157:H7 and its murine-specific relative Citrobacter rodentium, where it lies adjacent to genes implicated in sugar sensing and acquisition. C. rodentium ΔafuA was significantly impaired in an in vivo murine competitive assay as well as its ability to transmit infection from an afflicted to a naïve murine host. Sugar-phosphates were present in normal and infected intestinal mucus and stool samples, indicating that these metabolites are available within the intestinal lumen for enteric bacteria to import during infection. Our study shows that AfuABC-dependent uptake of sugar-phosphates plays a critical role during enteric bacterial infection and uncovers previously unrecognized roles for these metabolites as important contributors to successful pathogenesis.

  13. A three-scale analysis of bacterial communities involved in rocks colonization and soil formation in high mountain environments.

    Science.gov (United States)

    Esposito, Alfonso; Ciccazzo, Sonia; Borruso, Luigimaria; Zerbe, Stefan; Daffonchio, Daniele; Brusetti, Lorenzo

    2013-10-01

    Alpha and beta diversities of the bacterial communities growing on rock surfaces, proto-soils, riparian sediments, lichen thalli, and water springs biofilms in a glacier foreland were studied. We used three molecular based techniques to allow a deeper investigation at different taxonomic resolutions: denaturing gradient gel electrophoresis, length heterogeneity-PCR, and automated ribosomal intergenic spacer analysis. Bacterial communities were mainly composed of Acidobacteria, Proteobacteria, and Cyanobacteria with distinct variations among sites. Proteobacteria were more represented in sediments, biofilms, and lichens; Acidobacteria were mostly found in proto-soils; and Cyanobacteria on rocks. Firmicutes and Bacteroidetes were mainly found in biofilms. UniFrac P values confirmed a significant difference among different matrices. Significant differences (P rocks which shared a more similar community structure, while at deep taxonomic resolution two distinct bacterial communities between lichens and rocks were found.

  14. Function of Platelet-Induced Epithelial Attachment at Titanium Surfaces Inhibits Microbial Colonization.

    Science.gov (United States)

    Maeno, M; Lee, C; Kim, D M; Da Silva, J; Nagai, S; Sugawara, S; Nara, Y; Kihara, H; Nagai, M

    2017-06-01

    The aim of this study was to evaluate the barrier function of platelet-induced epithelial sheets on titanium surfaces. The lack of functional peri-implant epithelial sealing with basal lamina (BL) attachment at the interface of the implant and the adjacent epithelium allows for bacterial invasion, which may lead to peri-implantitis. Although various approaches have been reported to combat bacterial infection by surface modifications to titanium, none of these have been successful in a clinical application. In our previous study, surface modification with protease-activated receptor 4-activating peptide (PAR4-AP), which induced platelet activation and aggregation, was successful in demonstrating epithelial attachment via BL and epithelial sheet formation on the titanium surface. We hypothesized that the platelet-induced epithelial sheet on PAR4-AP-modified titanium surfaces would reduce bacterial attachment, penetration, and invasion. Titanium surface was modified with PAR4-AP and incubated with platelet-rich plasma (PRP). The aggregated platelets released collagen IV, a critical BL component, onto the PAR4-AP-modified titanium surface. Then, human gingival epithelial cells were seeded on the modified titanium surface and formed epithelial sheets. Green fluorescent protein (GFP)-expressing Escherichia coli was cultured onto PAR4-AP-modified titanium with and without epithelial sheet formation. While Escherichia coli accumulated densely onto the PAR4-AP titanium lacking epithelial sheet, few Escherichia coli were observed on the epithelial sheet on the PAR4-AP surface. No bacterial invasion into the interface of the epithelial sheet and the titanium surface was observed. These in vitro results indicate the efficacy of a platelet-induced epithelial barrier that functions to prevent bacterial attachment, penetration, and invasion on PAR4-AP-modified titanium.

  15. Gamma-cyclodextrin/usnic acid thin film fabricated by MAPLE for improving the resistance of medical surfaces to Staphylococcus aureus colonization

    Science.gov (United States)

    Iordache, Florin; Grumezescu, Valentina; Grumezescu, Alexandru Mihai; Curuţiu, Carmen; Diţu, Lia Mara; Socol, Gabriel; Ficai, Anton; Truşcă, Roxana; Holban, Alina Maria

    2015-05-01

    This study reports on the successful deposition of γ-cyclodextrin/usnic acid (γCD/UA) thin film by Matrix Assisted Pulsed Laser Evaporation (MAPLE) as anti-adherent coating on medical surfaces against microbial colonization. The obtained results demonstrate that these bioactive thin films inhibit Staphylococcus aureus biofilm formation at all stages, starting with their initiation. The antibiofilm effect was constant along the bacterial incubation time. Furthermore, the γCD/UA coatings show a great biocompatibility which means that this material is suitable for the development of modern medical devices with antimicrobial properties.

  16. The effects of omeprazole therapy on bacterial colonization of the pharynx in healthy dogs.

    Science.gov (United States)

    Sullivan, Lauren A; Wakayama, Justin; Boscan, Pedro L; Hyatt, Doreene R; Twedt, David C; Lappin, Michael R; Dargatz, David A

    2016-01-01

    To identify the relative abundance of commensal pharyngeal flora in healthy dogs and determine if abundance of pharyngeal flora is altered during omeprazole administration. Eight adult Beagles. A total of 3 baseline pharyngeal swabs, collected 48 hours apart, were obtained from each dog. Omeprazole (1 mg/kg PO q 24 h) was administered for a total of 12 days. During omeprazole administration, pharyngeal swabs were obtained on Days 8, 10, and 12. All swabs were submitted for semiquantitative aerobic and anaerobic culture. Growth of bacterial isolates, as well as genus of isolates, was compared between the pretreatment (n = 24) and treatment (n = 24) swabs. A greater abundance of several bacterial species was identified during the treatment period, including coagulase-negative Staphylococcus (P therapy. Further studies are warranted to determine the clinical significance of gastric acid suppressants on pharyngeal flora in dogs. © Veterinary Emergency and Critical Care Society 2015.

  17. Helicobacter pylori HP0231 Influences Bacterial Virulence and Is Essential for Gastric Colonization

    OpenAIRE

    Zhong, Yu; Anderl, Florian; Kruse, Tobias; Schindele, Franziska; Jagusztyn-Krynicka, Elzbieta Katarzyna; Fischer, Wolfgang; Gerhard, Markus; Mejias-Luque, Raquel

    2016-01-01

    The Dsb protein family is responsible for introducing disulfide bonds into nascent proteins in prokaryotes, stabilizing the structure of many proteins. Helicobacter pylori HP0231 is a Dsb-like protein, shown to catalyze disulfide bond formation and to participate in redox homeostasis. Notably, many H. pylori virulence factors are stabilized by the formation of disulfide bonds. By employing H. pylori HP0231 deficient strains we analyzed the effect of lack of this bacterial protein on the funct...

  18. Temporal Dynamics of Bacterial and Fungal Colonization on Plastic Debris in the North Sea.

    Science.gov (United States)

    De Tender, Caroline; Devriese, Lisa I; Haegeman, Annelies; Maes, Sara; Vangeyte, Jürgen; Cattrijsse, André; Dawyndt, Peter; Ruttink, Tom

    2017-07-05

    Despite growing evidence that biofilm formation on plastic debris in the marine environment may be essential for its biodegradation, the underlying processes have yet to be fully understood. Thus, far, bacterial biofilm formation had only been studied after short-term exposure or on floating plastic, yet a prominent share of plastic litter accumulates on the seafloor. In this study, we explored the taxonomic composition of bacterial and fungal communities on polyethylene plastic sheets and dolly ropes during long-term exposure on the seafloor, both at a harbor and an offshore location in the Belgian part of the North Sea. We reconstructed the sequence of events during biofilm formation on plastic in the harbor environment and identified a core bacteriome and subsets of bacterial indicator species for early, intermediate, and late stages of biofilm formation. Additionally, by implementing ITS2 metabarcoding on plastic debris, we identified and characterized for the first time fungal genera on plastic debris. Surprisingly, none of the plastics exposed to offshore conditions displayed the typical signature of a late stage biofilm, suggesting that biofilm formation is severely hampered in the natural environment where most plastic debris accumulates.

  19. Efficient responses to host and bacterial signals during Vibrio cholerae colonization

    Science.gov (United States)

    Rothenbacher, Francesca P; Zhu, Jun

    2014-01-01

    Vibrio cholerae, the microorganism responsible for the diarrheal disease cholera, is able to sense and respond to a variety of changing stimuli in both its aquatic and human gastrointestinal environments. Here we present a review of research efforts aimed toward understanding the signals this organism senses in the human host. V. cholerae’s ability to sense and respond to temperature and pH, bile, osmolarity, oxygen and catabolite levels, nitric oxide, and mucus, as well as the quorum sensing signals produced in response to these factors will be discussed. We also review the known quorum sensing regulatory pathways and discuss their importance with regard to the regulation of virulence and colonization during infection. PMID:24256715

  20. Molecular Analysis of Bacterial Microbiota on Brazilian Currency Note Surfaces

    Directory of Open Access Journals (Sweden)

    Tairacan Augusto Pereira da Fonseca

    2015-10-01

    Full Text Available Currency notes have been implicated as a vehicle for transmitting community-acquired bacterial infections. However, the overall diversity of the bacterial population residing on banknotes is still unknown in Brazil. In this study, we aimed to investigate the overall bacterial population from 150 different Brazilian Rial (R$ notes in circulation using a culture-independent Illumina massively parallel sequencing approach of the 16S rRNA genes. Samples were randomly collected from three different street markets or “feiras” in the metropolitan region of São Paulo. Taxonomical composition revealed the abundance of Proteobacteria phyla, followed by Firmicutes and Streptophyta, with a total of 1193 bacterial families and 3310 bacterial genera. Most of these bacterial genera are of human, animal, and environmental origins. Also, our analysis revealed the presence of some potential pathogenic bacterial genera including Salmonella, Staphylococcus, and Klebsiella. The results demonstrate that there is a tremendous diversity of bacterial contamination on currency notes, including organisms known to be opportunistic pathogens. One of the factors that may contribute to the richness of bacterial diversity in currency notes is personal hygiene. Thus, our results underscore the need to increase public awareness of the importance of personal hygiene of money handlers who also handle food.

  1. Molecular Analysis of Bacterial Microbiota on Brazilian Currency Note Surfaces.

    Science.gov (United States)

    Pereira da Fonseca, Tairacan Augusto; Pessôa, Rodrigo; Sanabani, Sabri Saeed

    2015-10-22

    Currency notes have been implicated as a vehicle for transmitting community-acquired bacterial infections. However, the overall diversity of the bacterial population residing on banknotes is still unknown in Brazil. In this study, we aimed to investigate the overall bacterial population from 150 different Brazilian Rial (R$) notes in circulation using a culture-independent Illumina massively parallel sequencing approach of the 16S rRNA genes. Samples were randomly collected from three different street markets or "feiras" in the metropolitan region of São Paulo. Taxonomical composition revealed the abundance of Proteobacteria phyla, followed by Firmicutes and Streptophyta, with a total of 1193 bacterial families and 3310 bacterial genera. Most of these bacterial genera are of human, animal, and environmental origins. Also, our analysis revealed the presence of some potential pathogenic bacterial genera including Salmonella, Staphylococcus, and Klebsiella. The results demonstrate that there is a tremendous diversity of bacterial contamination on currency notes, including organisms known to be opportunistic pathogens. One of the factors that may contribute to the richness of bacterial diversity in currency notes is personal hygiene. Thus, our results underscore the need to increase public awareness of the importance of personal hygiene of money handlers who also handle food.

  2. Fructose-enhanced reduction of bacterial growth on nanorough surfaces

    Directory of Open Access Journals (Sweden)

    Durmus NG

    2012-02-01

    Full Text Available Naside Gozde Durmus1, Erik N Taylor1, Fatih Inci3,4, Kim M Kummer1, Keiko M Tarquinio5, Thomas J Webster1,21School of Engineering, Brown University, Providence, RI, USA; 2Department of Orthopedics, Brown University, Providence, RI, USA; 3Bio-Acoustic-MEMS in Medicine (BAMM Laboratory, Center for Biomedical Engineering, Department of Medicine, Brigham and Women's Hospital, Harvard-MIT Health Sciences and Technology, Harvard Medical School, MA, USA; 4Istanbul Technical University, Molecular Biology-Genetics and Biotechnology Program, Mobgam, Maslak, Istanbul, Turkey; 5Division of Pediatric Critical Care Medicine, Rhode Island Hospital, Providence, RI, USAAbstract: Patients on mechanical ventilators for extended periods of time often face the risk of developing ventilator-associated pneumonia. During the ventilation process, patients incapable of breathing are intubated with polyvinyl chloride (PVC endotracheal tubes (ETTs. PVC ETTs provide surfaces where bacteria can attach and proliferate from the contaminated oropharyngeal space to the sterile bronchoalveolar area. To overcome this problem, ETTs can be coated with antimicrobial agents. However, such coatings may easily delaminate during use. Recently, it has been shown that changes in material topography at the nanometer level can provide antibacterial properties. In addition, some metabolites, such as fructose, have been found to increase the efficiency of antibiotics used to treat Staphylococcus aureus (S. aureus infections. In this study, we combined the antibacterial effect of nanorough ETT topographies with sugar metabolites to decrease bacterial growth and biofilm formation on ETTs. We present for the first time that the presence of fructose on the nanorough surfaces decreases the number of planktonic S. aureus bacteria in the solution and biofilm formation on the surface after 24 hours. We thus envision that this method has the potential to impact the future of surface engineering of

  3. Spectrum of bacterial colonization associated with urothelial cells from patients with chronic lower urinary tract symptoms.

    Science.gov (United States)

    Khasriya, Rajvinder; Sathiananthamoorthy, Sanchutha; Ismail, Salim; Kelsey, Michael; Wilson, Mike; Rohn, Jennifer L; Malone-Lee, James

    2013-07-01

    Chronic lower urinary tract symptoms (LUTS), such as urgency and incontinence, are common, especially among the elderly, but their etiology is often obscure. Recent studies of acute urinary tract infections implicated invasion by Escherichia coli into the cytoplasm of urothelial cells, with persistence of long-term bacterial reservoirs, but the role of infection in chronic LUTS is unknown. We conducted a large prospective study with eligible patients with LUTS and controls over a 3-year period, comparing routine urine cultures of planktonic bacteria with cultures of shed urothelial cells concentrated in centrifuged urinary sediments. This comparison revealed large numbers of bacteria undetected by routine cultures. Next, we typed the bacterial species cultured from patient and control sediments under both aerobic and anaerobic conditions, and we found that the two groups had complex but significantly distinct profiles of bacteria associated with their shed bladder epithelial cells. Strikingly, E. coli, the organism most responsible for acute urinary tract infections, was not the only or even the main offending pathogen in this more-chronic condition. Antibiotic protection assays with shed patient cells and in vitro infection studies using patient-derived strains in cell culture suggested that LUTS-associated bacteria are within or extremely closely associated with shed epithelial cells, which explains how routine cultures might fail to detect them. These data have strong implications for the need to rethink our common diagnoses and treatments of chronic urinary tract symptoms.

  4. Forces involved in bacterial adhesion to hydrophilic and hydrophobic surfaces

    NARCIS (Netherlands)

    Boks, N.P.; Norde, W.; Meil, H.C.; Busscher, H.J.

    2008-01-01

    Using a parallel-plate flow chamber, the hydrodynamic shear forces to prevent bacterial adhesion (F-prev) and to detach adhering bacteria (F-det) were evaluated for hydrophilic glass, hydrophobic, dimethyldichlorosilane (DDS)-coated glass and six different bacterial strains, in order to test the

  5. Forces involved in bacterial adhesion to hydrophilic and hydrophobic surfaces

    NARCIS (Netherlands)

    Boks, Niels P.; Norde, Willem; van der Mei, Henny C.; Busscher, Henk J.

    2008-01-01

    Using a parallel-plate flow chamber, the hydrodynamic shear forces to prevent bacterial adhesion (F(prev)) and to detach adhering bacteria (F(det)) were evaluated for hydrophilic glass, hydrophobic, dimethyldichlorosilane (DDS)-coated glass and six different bacterial strains, in order to test the

  6. Plant genotype-specific archaeal and bacterial endophytes but similar Bacillus antagonists colonize Mediterranean olive trees

    Directory of Open Access Journals (Sweden)

    Henry eMueller

    2015-03-01

    Full Text Available Endophytes have an intimate and often symbiotic interaction with their hosts. Less is known about the composition and function of endophytes in trees. In order to evaluate our hypothesis that plant genotype and origin have a strong impact on both, endophytes of leaves from 10 Olea europaea L. cultivars from the Mediterranean basin growing at a single agricultural site in Spain and from nine wild olive trees located in natural habitats in Greece, Cyprus and on Madeira Island were studied. The composition of the bacterial endophytic communities as revealed by 16S rRNA gene amplicon sequencing and the subsequent PCoA analysis showed a strong correlation to the plant genotypes. The bacterial distribution patterns were congruent with the plant origins in Eastern and Western areas of the Mediterranean basin. Subsequently, the endophytic microbiome of wild olives was shown to be closely related to those of cultivated olives of the corresponding geographic origins. The olive leaf endosphere harbored mostly Proteobacteria, followed by Firmicutes, Actinobacteria and Bacteroidetes. The detection of a high portion of archaeal taxa belonging to the phyla Thaumarchaeota, Crenarchaeota and Euryarchaeota in the amplicon libraries was an unexpected discovery, which was confirmed by quantitative real-time PCR revealing an archaeal portion of up to 35.8%. Although the function of these Archaea for their host plant remains speculative, this finding suggests a significant relevance of archaeal endophytes for plant-microbe interactions. In addition, the antagonistic potential of culturable endophytes was determined; all isolates with antagonistic activity against the olive-pathogenic fungus Verticillium dahliae Kleb. belong to Bacillus amyloliquefaciens. In contrast to the specific global structural diversity, BOX-fingerprints of the antagonistic Bacillus isolates were highly similar and independent of the olive genotype from which they were isolated.

  7. Plant genotype-specific archaeal and bacterial endophytes but similar Bacillus antagonists colonize Mediterranean olive trees.

    Science.gov (United States)

    Müller, Henry; Berg, Christian; Landa, Blanca B; Auerbach, Anna; Moissl-Eichinger, Christine; Berg, Gabriele

    2015-01-01

    Endophytes have an intimate and often symbiotic interaction with their hosts. Less is known about the composition and function of endophytes in trees. In order to evaluate our hypothesis that plant genotype and origin have a strong impact on both, endophytes of leaves from 10 Olea europaea L. cultivars from the Mediterranean basin growing at a single agricultural site in Spain and from nine wild olive trees located in natural habitats in Greece, Cyprus, and on Madeira Island were studied. The composition of the bacterial endophytic communities as revealed by 16S rRNA gene amplicon sequencing and the subsequent PCoA analysis showed a strong correlation to the plant genotypes. The bacterial distribution patterns were congruent with the plant origins in "Eastern" and "Western" areas of the Mediterranean basin. Subsequently, the endophytic microbiome of wild olives was shown to be closely related to those of cultivated olives of the corresponding geographic origins. The olive leaf endosphere harbored mostly Proteobacteria, followed by Firmicutes, Actinobacteria, and Bacteroidetes. The detection of a high portion of archaeal taxa belonging to the phyla Thaumarchaeota, Crenarchaeota, and Euryarchaeota in the amplicon libraries was an unexpected discovery, which was confirmed by quantitative real-time PCR revealing an archaeal portion of up to 35.8%. Although the function of these Archaea for their host plant remains speculative, this finding suggests a significant relevance of archaeal endophytes for plant-microbe interactions. In addition, the antagonistic potential of culturable endophytes was determined; all isolates with antagonistic activity against the olive-pathogenic fungus Verticillium dahliae Kleb. belong to Bacillus amyloliquefaciens. In contrast to the specific global structural diversity, BOX-fingerprints of the antagonistic Bacillus isolates were highly similar and independent of the olive genotype from which they were isolated.

  8. Influence of bacterial colonization of the healing screws on peri-implant tissue

    Directory of Open Access Journals (Sweden)

    Simonetta D'Ercole

    2013-06-01

    Conclusion: The healing screws left in situ for a period of 90 days caused a peri-implant inflammation and the presence of periodontal pathogenic bacteria in the peri-implant sulcus, due to the plaque accumulation on screw surfaces.

  9. Impervious Surfaces Alter Soil Bacterial Communities in Urban Areas: A Case Study in Beijing, China.

    Science.gov (United States)

    Hu, Yinhong; Dou, Xiaolin; Li, Juanyong; Li, Feng

    2018-01-01

    The rapid expansion of urbanization has caused land cover change, especially the increasing area of impervious surfaces. Such alterations have significant effects on the soil ecosystem by impeding the exchange of gasses, water, and materials between soil and the atmosphere. It is unclear whether impervious surfaces have any effects on soil bacterial diversity and community composition. In the present study, we conducted an investigation of bacterial communities across five typical land cover types, including impervious surfaces (concrete), permeable pavement (bricks with round holes), shrub coverage ( Buxus megistophylla Levl. ), lawns ( Festuca elata Keng ex E. Alexeev ), and roadside trees ( Sophora japonica Linn. ) in Beijing, to explore the response of bacteria to impervious surfaces. The soil bacterial communities were addressed by high-throughput sequencing of the bacterial 16S rRNA gene. We found that Proteobacteria , Actinobacteria , Acidobacteria , Bacteroidetes , Chloroflexi , and Firmicutes were the predominant phyla in urban soils. Soil from impervious surfaces presented a lower bacterial diversity, and differed greatly from other types of land cover. Soil bacterial diversity was predominantly affected by Zn, dissolved organic carbon (DOC), and soil moisture content (SMC). The composition of the bacterial community was similar under shrub coverage, roadside trees, and lawns, but different from beneath impervious surfaces and permeable pavement. Variance partitioning analysis showed that edaphic properties contributed to 12% of the bacterial community variation, heavy metal pollution explained 3.6% of the variation, and interaction between the two explained 33% of the variance. Together, our data indicate that impervious surfaces induced changes in bacterial community composition and decrease of bacterial diversity. Interactions between edaphic properties and heavy metals were here found to change the composition of the bacterial community and diversity

  10. Impervious Surfaces Alter Soil Bacterial Communities in Urban Areas: A Case Study in Beijing, China

    Directory of Open Access Journals (Sweden)

    Yinhong Hu

    2018-02-01

    Full Text Available The rapid expansion of urbanization has caused land cover change, especially the increasing area of impervious surfaces. Such alterations have significant effects on the soil ecosystem by impeding the exchange of gasses, water, and materials between soil and the atmosphere. It is unclear whether impervious surfaces have any effects on soil bacterial diversity and community composition. In the present study, we conducted an investigation of bacterial communities across five typical land cover types, including impervious surfaces (concrete, permeable pavement (bricks with round holes, shrub coverage (Buxus megistophylla Levl., lawns (Festuca elata Keng ex E. Alexeev, and roadside trees (Sophora japonica Linn. in Beijing, to explore the response of bacteria to impervious surfaces. The soil bacterial communities were addressed by high-throughput sequencing of the bacterial 16S rRNA gene. We found that Proteobacteria, Actinobacteria, Acidobacteria, Bacteroidetes, Chloroflexi, and Firmicutes were the predominant phyla in urban soils. Soil from impervious surfaces presented a lower bacterial diversity, and differed greatly from other types of land cover. Soil bacterial diversity was predominantly affected by Zn, dissolved organic carbon (DOC, and soil moisture content (SMC. The composition of the bacterial community was similar under shrub coverage, roadside trees, and lawns, but different from beneath impervious surfaces and permeable pavement. Variance partitioning analysis showed that edaphic properties contributed to 12% of the bacterial community variation, heavy metal pollution explained 3.6% of the variation, and interaction between the two explained 33% of the variance. Together, our data indicate that impervious surfaces induced changes in bacterial community composition and decrease of bacterial diversity. Interactions between edaphic properties and heavy metals were here found to change the composition of the bacterial community and

  11. Prevention of bacterial adhesion

    DEFF Research Database (Denmark)

    Klemm, Per; Vejborg, Rebecca Munk; Hancock, Viktoria

    2010-01-01

    Management of bacterial infections is becoming increasingly difficult due to the emergence and increasing prevalence of bacterial pathogens that are resistant to available antibiotics. Conventional antibiotics generally kill bacteria by interfering with vital cellular functions, an approach...... that imposes selection pressure for resistant bacteria. New approaches are urgently needed. Targeting bacterial virulence functions directly is an attractive alternative. An obvious target is bacterial adhesion. Bacterial adhesion to surfaces is the first step in colonization, invasion, and biofilm formation....... As such, adhesion represents the Achilles heel of crucial pathogenic functions. It follows that interference with adhesion can reduce bacterial virulence. Here, we illustrate this important topic with examples of techniques being developed that can inhibit bacterial adhesion. Some of these will become...

  12. Bacterial diversity in relation to secondary production and succession on surfaces of the kelp Laminaria hyperborea

    Science.gov (United States)

    Bengtsson, Mia M; Sjøtun, Kjersti; Lanzén, Anders; Øvreås, Lise

    2012-01-01

    Kelp forests worldwide are known as hotspots for macroscopic biodiversity and primary production, yet very little is known about the biodiversity and roles of microorganisms in these ecosystems. Secondary production by heterotrophic bacteria associated to kelp is important in the food web as a link between kelp primary production and kelp forest consumers. The aim of this study was to investigate the relationship between bacterial diversity and two important processes in this ecosystem; bacterial secondary production and primary succession on kelp surfaces. To address this, kelp, Laminaria hyperborea, from southwestern Norway was sampled at different geographical locations and during an annual cycle. Pyrosequencing (454-sequencing) of amplicons of the 16S rRNA gene of bacteria was used to study bacterial diversity. Incorporation of tritiated thymidine was used as a measure of bacterial production. Our data show that bacterial diversity (richness and evenness) increases with the age of the kelp surface, which corresponds to the primary succession of its bacterial communities. Higher evenness of bacterial operational taxonomical units (OTUs) is linked to higher bacterial production. Owing to the dominance of a few abundant OTUs, kelp surface biofilm communities may be characterized as low-diversity habitats. This is the first detailed study of kelp-associated bacterial communities using high-throughput sequencing and it extends current knowledge on microbial community assembly and dynamics on living surfaces. PMID:22763650

  13. Application of air ions for bacterial de-colonization in air filters contaminated by aerosolized bacteria

    International Nuclear Information System (INIS)

    Kim, Yang Seon; Yoon, Ki Young; Park, Jae Hong; Hwang, Jungho

    2011-01-01

    We aerosolized the Escherichia coli (E. coli) and Staphylococcus epidermidis (S. epidermidis) bacteria and collected them on membrane filters. Then we generated air ions by applying a high voltage to a carbon fiber tip and applied them to the contaminated filters. The antibacterial efficiency was not significantly affected by the bacteria being Gram-positive or Gram-negative, however, negative ions showed a lower antibacterial efficiency than positive ions to both E. coli and S. epidermidis, even though the concentration of negative air ions was much higher than that of positive air ions. With a field emission scanning electron microscope (FE-SEM) images and fluorescence microscopy images using a LIVE/DEAD BacLight Bacterial Viability Kit, electrostatic disruption of the bacteria was found to be the dominant antibacterial effect. - Research Highlights: →This study examined the effects of air ions generated by a carbon fiber ionizer on the inactivation of bioaerosols. →When the ion exposure time and the ion generation concentration were increased, the antibacterial efficiency increased. →The bioaerosols carried a significant number of negative electrical charges. →Negative ions showed lower antibacterial efficiency than positive ions to both E. coli and S. epidermidis, even though the concentration of negative air ions was much higher than that of positive air ions.

  14. Hard-bottom succession of subtidal epibenthic communities colonizing hidden and exposed surfaces off northern Chile

    Directory of Open Access Journals (Sweden)

    Aldo S. Pacheco

    2010-03-01

    Full Text Available The biodiversity of hard-bottom substrata comprises species growing on exposed rock and in hidden microhabitats, such as cracks and crevices. This study examines the succession of epibenthic organisms colonizing an artificial substratum with one surface exposed and one surface hidden on a vertical wall off northern Chile. On each sampling date species coverage of three replicate panels on both surfaces was assessed. The hidden surface was dominated in terms of coverage by the bryozoans Membranipora isabelleana and Lagenicella variabilis, while algae were absent. In contrast, the exposed surface was dominated by encrusting red corallines and the red alga Rhodymenia corallina. At the end of the experimental period both surfaces were dominated by colonial suspension feeders, but showed a different community structure and successional pattern. On the exposed surface, competitive exclusion was identified as an important aspect of succession, whereas on the hidden surface this pattern was not observed. These findings have implications for overall biodiversity, because pioneer species that are not able to survive long periods on exposed surfaces become restricted to hidden surfaces, from where they spread laterally. Thus, hidden microhabitats provide refuges for certain species, and may play an important role in the overall succession on rock faces. We conclude that examination of hidden microhabitats is necessary in order to fully understand succession in hard-bottom habitats.

  15. Initial Inoculation Concentration Does Not Affect Final Bacterial Colonization of In vitro Vascular Conduits.

    Science.gov (United States)

    Heafner, Thomas A; Lewis, Clayton; Baluh, Graham; Clemens, Michael; Propper, Brandon; Arthurs, Zachary M

    2018-02-21

    Despite improved peri-operative care, prosthetic graft infections continue to cause substantial morbidity and mortality. Contemporary graft infection models have tested a conduit's infectability using varying concentrations without standardization. Using a static assay in vitro model, we sought to evaluate the impact of inoculation concentration on vascular conduit attachment. The 2-hour and 24-hour attachment of Staphylococcus aureus TCH1516 and Pseudomonas aeruginosa PA01-UW were determined on polytetrafluoroethylene (PTFE), Dacron ® , nitinol, cobalt chromium, and Viabahn ® (W.L. Gore and Associates, Newark, DE) endoprotheses. Individually and in combination, concentrations at 10 4 , 10 5 , 10 6 , 10 7 , and 10 8 were tested on 2-mm sections of each graft. After each time interval, the prosthetics were rinsed to remove non-attached bacteria, sonicated to release the attached bacteria, spiral plated, and then analyzed for the attached concentration. After two hours, the higher initial inoculation concentration translated into a higher attachment percentage, but the mean attachment percentage was only 14.8% in the 10 8 group. Pseudomonas aeruginosa had the greatest mean attachment across all material and concentration groups. The sequence of attachment on the conduits followed a constant order: Dacron, PTFE, cobalt, nitinol, and Viabahn with no difference between Dacron and PTFE. Although there were still differences at the 24-hour mark, the median attachment at each concentration was greater than the highest initial concentration (10 8 ). Initial attachment percentage is poor consistently regardless of inoculation concentration, however, Staphylococcus aureus and Pseudomonas aeruginosa are still able to achieve full attachment after 24 hours. A concentration of less than 10 7 should be used in vascular graft infection models to ensure adequate bacterial attachment.

  16. Enhancement and suppression effects of a nanopatterned surface on bacterial adhesion

    Science.gov (United States)

    Li, Xinlei; Chen, Tongsheng

    2016-05-01

    We present a quantitative thermodynamic model to elucidate the effects of a nanopatterned surface on bacterial adhesion. Based on the established model, we studied the equilibrium state of rodlike bacterial cells adhered to a nanopillar-patterned surface. Theoretical analyses showed the physical origin of bacterial adhesion on a nanopatterned surface is actually determined by the balance between adhesion energy and deformation energy of the cell membrane. We found that there are enhancement effects on bacterial adhesion to the patterned surface with large radius and small spacing of nanopillars, but suppression effects for nanopillars with a radius smaller than a critical value. In addition, according to our model, a phase diagram has been constructed which can clarify the interrelated effects of the radius and the spacing of nanopillars. The broad agreement with experimental observations implies that these studies would provide useful guidance to the design of nanopatterned surfaces for biomedical applications.

  17. Comparison of the effect of topical application of human milk and dry cord care on the bacterial colonization of umbilical cord in newborn infants

    OpenAIRE

    Fatemeh Abbaszadeh; zanab Hajizadeh; Mahboobeh Kafaei Atrian; Azam Bagheri; Nahid Sarafraz

    2014-01-01

    Background: Breast milk contains significant amounts of compounds that act as natural antimicrobial agents. This study was conducted to compare the effect of topical application of human milk and dry cord care on bacterial colonization in the umbilical cord of newborn infants. Methods: This clinical trial study was carried out on 174 infants in Kashan. The newborns were randomized to mother's milk group and dry cord care group from the birth. In group 1, the mother rubbed her own milk on ...

  18. SIGIRR, a negative regulator of TLR/IL-1R signalling promotes Microbiota dependent resistance to colonization by enteric bacterial pathogens.

    Directory of Open Access Journals (Sweden)

    Ho Pan Sham

    Full Text Available Enteric bacterial pathogens such as enterohemorrhagic E. coli (EHEC and Salmonella Typhimurium target the intestinal epithelial cells (IEC lining the mammalian gastrointestinal tract. Despite expressing innate Toll-like receptors (TLRs, IEC are innately hypo-responsive to most bacterial products. This is thought to prevent maladaptive inflammatory responses against commensal bacteria, but it also limits antimicrobial responses by IEC to invading bacterial pathogens, potentially increasing host susceptibility to infection. One reason for the innate hypo-responsiveness of IEC is their expression of Single Ig IL-1 Related Receptor (SIGIRR, a negative regulator of interleukin (IL-1 and TLR signaling. To address whether SIGIRR expression and the innate hypo-responsiveness of IEC impacts on enteric host defense, Sigirr deficient (-/- mice were infected with the EHEC related pathogen Citrobacter rodentium. Sigirr -/- mice responded with accelerated IEC proliferation and strong pro-inflammatory and antimicrobial responses but surprisingly, Sigirr -/- mice proved dramatically more susceptible to infection than wildtype mice. Through haematopoietic transplantation studies, it was determined that SIGIRR expression by non-haematopoietic cells (putative IEC regulated these responses. Moreover, the exaggerated responses were found to be primarily dependent on IL-1R signaling. Whilst exploring the basis for their susceptibility, Sigirr -/- mice were found to be unusually susceptible to intestinal Salmonella Typhimurium colonization, developing enterocolitis without the typical requirement for antibiotic based removal of competing commensal microbes. Strikingly, the exaggerated antimicrobial responses seen in Sigirr -/- mice were found to cause a rapid and dramatic loss of commensal microbes from the infected intestine. This depletion appears to reduce the ability of the microbiota to compete for space and nutrients (colonization resistance with the invading

  19. Atomic force microscopy studies of bioprocess engineering surfaces - imaging, interactions and mechanical properties mediating bacterial adhesion.

    Science.gov (United States)

    James, Sean A; Hilal, Nidal; Wright, Chris J

    2017-07-01

    The detrimental effect of bacterial biofilms on process engineering surfaces is well documented. Thus, interest in the early stages of bacterial biofilm formation; in particular bacterial adhesion and the production of anti-fouling coatings has grown exponentially as a field. During this time, Atomic force microscopy (AFM) has emerged as a critical tool for the evaluation of bacterial adhesion. Due to its versatility AFM offers not only insight into the topographical landscape and mechanical properties of the engineering surfaces, but elucidates, through direct quantification the topographical and biomechnical properties of the foulants The aim of this review is to collate the current research on bacterial adhesion, both theoretical and practical, and outline how AFM as a technique is uniquely equipped to provide further insight into the nanoscale world at the bioprocess engineering surface. Copyright © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Vaginal epithelial cells regulate membrane adhesiveness to co-ordinate bacterial adhesion

    NARCIS (Netherlands)

    Younes, Jessica A.; Klappe, Karin; Kok, Jan Willem; Busscher, Henk J.; Reid, Gregor; van der Mei, Henny C.

    Vaginal epithelium is colonized by different bacterial strains and species. The bacterial composition of vaginal biofilms controls the balance between health and disease. Little is known about the relative contribution of the epithelial and bacterial cell surfaces to bacterial adhesion and whether

  1. Growth promotion and colonization of switchgrass (Panicum virgatum cv. Alamo by bacterial endophyte Burkholderia phytofirmans strain PsJN

    Directory of Open Access Journals (Sweden)

    Kim Seonhwa

    2012-05-01

    Full Text Available Abstract Background Switchgrass is one of the most promising bioenergy crop candidates for the US. It gives relatively high biomass yield and can grow on marginal lands. However, its yields vary from year to year and from location to location. Thus it is imperative to develop a low input and sustainable switchgrass feedstock production system. One of the most feasible ways to increase biomass yields is to harness benefits of microbial endophytes. Results We demonstrate that one of the most studied plant growth promoting bacterial endophytes, Burkholderia phytofirmans strain PsJN, is able to colonize and significantly promote growth of switchgrass cv. Alamo under in vitro, growth chamber, and greenhouse conditions. In several in vitro experiments, the average fresh weight of PsJN-inoculated plants was approximately 50% higher than non-inoculated plants. When one-month-old seedlings were grown in a growth chamber for 30 days, the PsJN-inoculated Alamo plants had significantly higher shoot and root biomass compared to controls. Biomass yield (dry weight averaged from five experiments was 54.1% higher in the inoculated treatment compared to non-inoculated control. Similar results were obtained in greenhouse experiments with transplants grown in 4-gallon pots for two months. The inoculated plants exhibited more early tillers and persistent growth vigor with 48.6% higher biomass than controls. We also found that PsJN could significantly promote growth of switchgrass cv. Alamo under sub-optimal conditions. However, PsJN-mediated growth promotion in switchgrass is genotype specific. Conclusions Our results show B. phytofirmans strain PsJN significantly promotes growth of switchgrass cv. Alamo under different conditions, especially in the early growth stages leading to enhanced production of tillers. This phenomenon may benefit switchgrass establishment in the first year. Moreover, PsJN significantly stimulated growth of switchgrass cv. Alamo under sub

  2. Diversity of Bacterial Communities of Fitness Center Surfaces in a U.S. Metropolitan Area

    Directory of Open Access Journals (Sweden)

    Nabanita Mukherjee

    2014-12-01

    Full Text Available Public fitness centers and exercise facilities have been implicated as possible sources for transmitting community-acquired bacterial infections. However, the overall diversity of the bacterial community residing on the surfaces in these indoor environments is still unknown. In this study, we investigated the overall bacterial ecology of selected fitness centers in a metropolitan area (Memphis, TN, USA utilizing culture-independent pyrosequencing of the 16S rRNA genes. Samples were collected from the skin-contact surfaces (e.g., exercise instruments, floor mats, handrails, etc. within fitness centers. Taxonomical composition revealed the abundance of Firmicutes phyla, followed by Proteobacter and Actinobacteria, with a total of 17 bacterial families and 25 bacterial genera. Most of these bacterial genera are of human and environmental origin (including, air, dust, soil, and water. Additionally, we found the presence of some pathogenic or potential pathogenic bacterial genera including Salmonella, Staphylococcus, Klebsiella, and Micrococcus. Staphylococcus was found to be the most prevalent genus. Presence of viable forms of these pathogens elevates risk of exposure of any susceptible individuals. Several factors (including personal hygiene, surface cleaning and disinfection schedules of the facilities may be the reasons for the rich bacterial diversity found in this study. The current finding underscores the need to increase public awareness on the importance of personal hygiene and sanitation for public gym users.

  3. Diversity of bacterial communities of fitness center surfaces in a U.S. metropolitan area.

    Science.gov (United States)

    Mukherjee, Nabanita; Dowd, Scot E; Wise, Andy; Kedia, Sapna; Vohra, Varun; Banerjee, Pratik

    2014-12-03

    Public fitness centers and exercise facilities have been implicated as possible sources for transmitting community-acquired bacterial infections. However, the overall diversity of the bacterial community residing on the surfaces in these indoor environments is still unknown. In this study, we investigated the overall bacterial ecology of selected fitness centers in a metropolitan area (Memphis, TN, USA) utilizing culture-independent pyrosequencing of the 16S rRNA genes. Samples were collected from the skin-contact surfaces (e.g., exercise instruments, floor mats, handrails, etc.) within fitness centers. Taxonomical composition revealed the abundance of Firmicutes phyla, followed by Proteobacter and Actinobacteria, with a total of 17 bacterial families and 25 bacterial genera. Most of these bacterial genera are of human and environmental origin (including, air, dust, soil, and water). Additionally, we found the presence of some pathogenic or potential pathogenic bacterial genera including Salmonella, Staphylococcus, Klebsiella, and Micrococcus. Staphylococcus was found to be the most prevalent genus. Presence of viable forms of these pathogens elevates risk of exposure of any susceptible individuals. Several factors (including personal hygiene, surface cleaning and disinfection schedules of the facilities) may be the reasons for the rich bacterial diversity found in this study. The current finding underscores the need to increase public awareness on the importance of personal hygiene and sanitation for public gym users.

  4. Effect of micro- and nanoscale topography on the adhesion of bacterial cells to solid surfaces.

    Science.gov (United States)

    Hsu, Lillian C; Fang, Jean; Borca-Tasciuc, Diana A; Worobo, Randy W; Moraru, Carmen I

    2013-04-01

    Attachment and biofilm formation by bacterial pathogens on surfaces in natural, industrial, and hospital settings lead to infections and illnesses and even death. Minimizing bacterial attachment to surfaces using controlled topography could reduce the spreading of pathogens and, thus, the incidence of illnesses and subsequent human and financial losses. In this context, the attachment of key microorganisms, including Escherichia coli, Listeria innocua, and Pseudomonas fluorescens, to silica and alumina surfaces with micron and nanoscale topography was investigated. The results suggest that orientation of the attached cells occurs preferentially such as to maximize their contact area with the surface. Moreover, the bacterial cells exhibited different morphologies, including different number and size of cellular appendages, depending on the topographical details of the surface to which they attached. This suggests that bacteria may utilize different mechanisms of attachment in response to surface topography. These results are important for the design of novel microbe-repellant materials.

  5. A pathogen-inducible patatin-like lipid acyl hydrolase facilitates fungal and bacterial host colonization in Arabidopsis.

    Science.gov (United States)

    La Camera, Sylvain; Geoffroy, Pierrette; Samaha, Hala; Ndiaye, Abdoulaye; Rahim, Gwendoline; Legrand, Michel; Heitz, Thierry

    2005-12-01

    Genes and proteins related to patatin, the major storage protein of potato tubers, have been identified in many plant species and shown to be induced by a variety of environmental stresses. The Arabidopsis patatin-like gene family (PLPs) comprises nine members, two of which (PLP2 and PLP7) are strongly induced in leaves challenged with fungal and bacterial pathogens. Here we show that accumulation of PLP2 protein in response to Botrytis cinerea or Pseudomonas syringae pv. tomato (avrRpt2) is dependent on jasmonic acid and ethylene signaling, but is not dependent on salicylic acid. Expression of a PLP2-green fluorescent protein (GFP) fusion protein and analysis of recombinant PLP2 indicates that PLP2 encodes a cytoplasmic lipid acyl hydrolase with wide substrate specificity. Transgenic plants with altered levels of PLP2 protein were generated and assayed for pathogen resistance. Plants silenced for PLP2 expression displayed enhanced resistance to B. cinerea, whereas plants overexpressing PLP2 were much more sensitive to this necrotrophic fungus. We also established a positive correlation between the level of PLP2 expression in transgenic plants and cell death or damage in response to paraquat treatment or infection by avirulent P. syringae. Interestingly, repression of PLP2 expression increased resistance to avirulent bacteria, while PLP2-overexpressing plants multiplied avirulent bacteria close to the titers reached by virulent bacteria. Collectively, the data indicate that PLP2-encoded lipolytic activity can be exploited by pathogens with different lifestyles to facilitate host colonization. In particular PLP2 potentiates plant cell death inflicted by Botrytis and reduces the efficiency of the hypersensitive response in restricting the multiplication of avirulent bacteria. Both effects are possibly mediated by providing fatty acid precursors of bioactive oxylipins.

  6. Rhizospheric Bacterial Strain Brevibacterium casei MH8a Colonizes Plant Tissues and Enhances Cd, Zn, Cu Phytoextraction by White Mustard.

    Science.gov (United States)

    Płociniczak, Tomasz; Sinkkonen, Aki; Romantschuk, Martin; Sułowicz, Sławomir; Piotrowska-Seget, Zofia

    2016-01-01

    Environmental pollution by heavy metals has become a serious problem in the world. Phytoextraction, which is one of the plant-based technologies, has attracted the most attention for the bioremediation of soils polluted with these contaminants. The aim of this study was to determine whether the multiple-tolerant bacterium, Brevibacterium casei MH8a isolated from the heavy metal-contaminated rhizosphere soil of Sinapis alba L., is able to promote plant growth and enhance Cd, Zn, and Cu uptake by white mustard under laboratory conditions. Additionally, the ability of the rifampicin-resistant spontaneous mutant of MH8a to colonize plant tissues and its mechanisms of plant growth promotion were also examined. In order to assess the ecological consequences of bioaugmentation on autochthonous bacteria, the phospholipid fatty acid (PLFA) analysis was used. The MH8a strain exhibited the ability to produce ammonia, 1-amino-cyclopropane-1-carboxylic acid deaminase, indole 3-acetic acid and HCN but was not able to solubilize inorganic phosphate and produce siderophores. Introduction of MH8a into soil significantly increased S. alba biomass and the accumulation of Cd (208%), Zn (86%), and Cu (39%) in plant shoots in comparison with those grown in non-inoculated soil. Introduced into the soil, MH8a was able to enter the plant and was found in the roots and leaves of inoculated plants thus indicating its endophytic features. PLFA analysis revealed that the MH8a that was introduced into soil had a temporary influence on the structure of the autochthonous bacterial communities. The plant growth-promoting features of the MH8a strain and its ability to enhance the metal uptake by white mustard and its long-term survival in soil as well as its temporary impact on autochthonous microorganisms make the strain a suitable candidate for the promotion of plant growth and the efficiency of phytoextraction.

  7. Rhizospheric bacterial strain Brevibacterium casei MH8a colonizes plant tissues and enhances Cd, Zn, Cu phytoextraction by white mustard

    Directory of Open Access Journals (Sweden)

    Tomasz ePłociniczak

    2016-02-01

    Full Text Available Environmental pollution by heavy metals has become a serious problem in the world. Phytoextraction, which is one of the plant-based technologies, has attracted the most attention for the bioremediation of soils polluted with these contaminants.The aim of this study was to determine whether the multiple-tolerant bacterium, Brevibacterium casei MH8a isolated from the heavy metal-contaminated rhizosphere soil of Sinapis alba L., is able to promote plant growth and enhance Cd, Zn and Cu uptake by white mustard under laboratory conditions. Additionally, the ability of the rifampicin-resistant spontaneous mutant of MH8a to colonize plant tissues and its mechanisms of plant growth promotion were also examined. In order to assess the ecological consequences of bioaugmentation on autochthonous bacteria, the phospholipid fatty acid (PLFA analysis was used. The MH8a strain exhibited the ability to produce ammonia, 1-amino-cyclopropane-1-carboxylic acid deaminase, indole 3-acetic acid and HCN but was not able to solubilize inorganic phosphate and produce siderophores. Introduction of MH8a into soil significantly increased S. alba biomass and the accumulation of Cd (208%, Zn (86% and Cu (39% in plant shoots in comparison with those grown in non-inoculated soil. Introduced into the soil, MH8a was able to enter the plant and was found in the roots and leaves of inoculated plants thus indicating its endophytic features. PLFA analysis revealed that the MH8a that was introduced into soil had a temporary influence on the structure of the autochthonous bacterial communities. The plant growth-promoting features of the MH8a strain and its ability to enhance the metal uptake by white mustard and its long-term survival in soil as well as its temporary impact on autochthonous microorganisms make the strain a suitable candidate for the promotion of plant growth and the efficiency of phytoextraction.

  8. The effect of smoking on CT score, bacterial colonization and distribution of inflammatory cells in the upper airways of patients with chronic rhinosinusitis.

    Science.gov (United States)

    Uhliarova, Barbora; Adamkov, Marian; Svec, Martin; Calkovska, Andrea

    2014-06-01

    The study was designed to determine whether smoking affects CT score, bacterial colonization of the upper airways and distribution of inflammatory cells in nasal mucosa in patients with chronic rhinosinusitis. Sixty-four patients were enrolled in the prospective study. We characterized differences in CT score, rate of revision surgery, differences in bacterial colonization in the middle nasal meatus and distribution of inflammatory cells in nasal tissue in smoking and non-smoking patients with chronic rhinosinusitis with nasal polyps (CRSwNP), chronic rhinosinusitis without nasal polyps (CRSsNP) and control group. Direct tobacco use was associated with significantly more severe form of the disease according to the preoperative CT investigation of paranasal sinuses using Lund-Mackay scoring system in both CRSwNP (p = 0.035) and CRSsNP (p = 0.023) groups. More intense colonization of upper-respiratory tract by the pathogenic bacteria in smokers compared to non-smokers was found. Non-pathogenic bacterial flora was more often present in non-smokers compared to smokers. Plasma cells and lymphocytes were the most numerous cells in nasal tissue in all three groups. In smokers with presence of pathogenic bacteria in middle nasal meatus there was stronger neutrophil (p = 0.002) and macrophage infiltration (p = 0.044) in CRSsNP group. Tobacco smoke exposure is related to higher Lund-Mackay score, increased colonization by pathogenic bacteria and lower incidence of commensals in middle nasal meatus, but does not influence cell distribution in nasal mucosa in patients with chronic rhinosinusitis.

  9. Bacterial community diversity and variation in spray water sources and the tomato fruit surface

    Directory of Open Access Journals (Sweden)

    Ottesen Andrea R

    2011-04-01

    Full Text Available Abstract Background Tomato (Solanum lycopersicum consumption has been one of the most common causes of produce-associated salmonellosis in the United States. Contamination may originate from animal waste, insects, soil or water. Current guidelines for fresh tomato production recommend the use of potable water for applications coming in direct contact with the fruit, but due to high demand, water from other sources is frequently used. We sought to describe the overall bacterial diversity on the surface of tomato fruit and the effect of two different water sources (ground and surface water when used for direct crop applications by generating a 454-pyrosequencing 16S rRNA dataset of these different environments. This study represents the first in depth characterization of bacterial communities in the tomato fruit surface and the water sources commonly used in commercial vegetable production. Results The two water sources tested had a significantly different bacterial composition. Proteobacteria was predominant in groundwater samples, whereas in the significantly more diverse surface water, abundant phyla also included Firmicutes, Actinobacteria and Verrucomicrobia. The fruit surface bacterial communities on tomatoes sprayed with both water sources could not be differentiated using various statistical methods. Both fruit surface environments had a high representation of Gammaproteobacteria, and within this class the genera Pantoea and Enterobacter were the most abundant. Conclusions Despite the major differences observed in the bacterial composition of ground and surface water, the season long use of these very different water sources did not have a significant impact on the bacterial composition of the tomato fruit surface. This study has provided the first next-generation sequencing database describing the bacterial communities living in the fruit surface of a tomato crop under two different spray water regimes, and therefore represents an

  10. Facile method to stain the bacterial cell surface for super-resolution fluorescence microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gunsolus, Ian L.; Hu, Dehong; Mihai, Cosmin; Lohse, Samuel E.; Lee, Chang-Soo; Torelli, Marco; Hamers, Robert J.; Murphy, Catherine; Orr, Galya; Haynes, Christy L.

    2014-01-01

    A method to fluorescently stain the surfaces of both Gram-negative and Gram-positive bacterial cells compatible with super-resolution fluorescence microscopy is presented. This method utilizes a commercially-available fluorescent probe to label primary amines at the surface of the cell. We demonstrate efficient staining of two bacterial strains, the Gram-negative Shewanella oneidensis MR-1 and the Gram-positive Bacillus subtilis 168. Using structured illumination microscopy and stochastic optical reconstruction microscopy, which require high quantum yield or specialized dyes, we show that this staining method may be used to resolve the bacterial cell surface with sub-diffraction-limited resolution. We further use this method to identify localization patterns of nanomaterials, specifically cadmium selenide quantum dots, following interaction with bacterial cells.

  11. Bacterial Surface Glycans: Microarray and QCM Strategies for Glycophenotyping and Exploration of Recognition by Host Receptors.

    Science.gov (United States)

    Kalograiaki, Ioanna; Campanero-Rhodes, María A; Proverbio, Davide; Euba, Begoña; Garmendia, Junkal; Aastrup, Teodor; Solís, Dolores

    2018-01-01

    Bacterial surfaces are decorated with a diversity of carbohydrate structures that play important roles in the bacteria-host relationships. They may offer protection against host defense mechanisms, elicit strong antigenic responses, or serve as ligands for host receptors, including lectins of the innate immune system. Binding by these lectins may trigger defense responses or, alternatively, promote attachment, thereby enhancing infection. The outcome will depend on the particular bacterial surface landscape, which may substantially differ among species and strains. In this chapter, we describe two novel methods for exploring interactions directly on the bacterial surface, based on the generation of bacterial microarrays and quartz crystal microbalance (QCM) sensor chips. Bacterial microarrays enable profiling of accessible carbohydrate structures and screening of their recognition by host receptors, also providing information on binding avidity, while the QCM approach allows determination of binding affinity and kinetics. In both cases, the chief element is the use of entire bacterial cells, so that recognition of the bacterial glycan epitopes is explored in their natural environment. © 2018 Elsevier Inc. All rights reserved.

  12. Bacteroidales Secreted Antimicrobial Proteins Target Surface Molecules Necessary for Gut Colonization and Mediate Competition In Vivo

    Directory of Open Access Journals (Sweden)

    Kevin G. Roelofs

    2016-08-01

    Full Text Available We recently showed that human gut Bacteroidales species secrete antimicrobial proteins (BSAPs, and we characterized in vitro the first such BSAP produced by Bacteroides fragilis. In this study, we identified a second potent BSAP produced by the ubiquitous and abundant human gut species Bacteroides uniformis. The two BSAPs contain a membrane attack complex/perforin (MACPF domain but share very little sequence similarity. We identified the target molecules of BSAP-sensitive cells and showed that each BSAP targets a different class of surface molecule: BSAP-1 targets an outer membrane protein of sensitive B. fragilis strains, and BSAP-2 targets the O-antigen glycan of lipopolysaccharide (LPS of sensitive B. uniformis strains. Species-wide genomic and phenotypic analyses of B. fragilis and B. uniformis showed that BSAP-producing strains circumvent killing by synthesizing an orthologous nontargeted surface molecule. The BSAP genes are adjacent to the gene(s encoding their target replacements, suggesting coacquisition. Using a gnotobiotic mouse competitive-colonization model, we found that the BSAP surface targets are important for colonization of the mammalian gut, thereby explaining why they are maintained in sensitive strains and why they were replaced rather than deleted in BSAP-producing strains. Using isogenic BSAP-producing, -sensitive, and -resistant strains, we show that a BSAP-producing strain outcompetes a sensitive strain but not a resistant strain in the mammalian gut. Human gut metagenomic datasets reveal that BSAP-1-sensitive strains do not cooccur with BSAP-1-producing strains in human gut microbiotas, further supporting the idea that BSAPs are important competitive factors with relevance to the strain-level composition of the human gut microbiota.

  13. Contribution of the Collagen-Binding Proteins of Streptococcus mutans to Bacterial Colonization of Inflamed Dental Pulp.

    Science.gov (United States)

    Nomura, Ryota; Ogaya, Yuko; Nakano, Kazuhiko

    2016-01-01

    Streptococcus mutans is a major pathogen of dental caries. Collagen-binding proteins (CBPs) (approximately 120 kDa), termed Cnm and Cbm, are regarded as important cell surface antigens related to the adherence of S. mutans to collagenous tissue. Furthermore, CBP-positive S. mutans strains are associated with various systemic diseases involving bacteremia, such as infective endocarditis. Endodontic infection is considered to be an important cause of bacteremia, but little is known regarding the presence of S. mutans in dental pulp tissue. In the present study, the distribution and virulence of S. mutans in dental pulp tissues were investigated by focusing on CBPs. Adhesion and invasion properties of various S. mutans strains were analyzed using human dental pulp fibroblasts (HDPFs). CBP-positive strains had a significantly higher rate of adhesion to HDPFs compared with CBP-defective isogenic mutant strains (Pmutans strains isolated from infected root canal specimens was then analyzed by PCR. We found that approximately 50% of the root canal specimens were positive for S. mutans. Approximately 20% of these strains were Cnm-positive, while no Cbm-positive strains were isolated. The Cnm-positive strains isolated from the specimens showed adhesion to HDPFs. Our results suggest that CBP-positive S. mutans strains exhibit high colonization in dental pulp. This could be a possible virulence factor for various systemic diseases.

  14. DGGE and 16S rDNA sequencing analysis of bacterial communities in colon content and feces of pigs fed whole crop rice.

    Science.gov (United States)

    Wang, Hai-Feng; Zhu, Wei-Yun; Yao, Wen; Liu, Jian-Xin

    2007-01-01

    The effect of feeding whole crop rice (WCR) to growing-finishing pigs at three levels 0 (Control), 10% and 20% on bacterial communities in colon content and feces was analyzed using 16S rDNA-based techniques. Amplicons of the V6-V8 variable regions of bacterial 16S rDNA were analyzed by denaturing gradient gel electrophoresis (DGGE), cloning and sequencing. The total number of DGGE bands and Shannon index of diversity for feces samples were higher in the pigs fed WCR-containing diets compared with the control, while a decrease trend was observed in these two parameters for colon content samples with the inclusion of WCR in the diets, although statistical differences were not significant. In general, the intestinal bacterial communities were prone to form the cluster for pig fed the same diet. Feeding of WCR induced the presence of special DGGE band with the sequence showing 99% similarity to that of Lactobacillus reuteri (DSM 20016T). The sequences of seven amplicons in total nine clones showed less than 97% similarity with those of previously identified or unidentified bacteria, suggesting that most bacteria in gastrointestinal tracts have not been cultured or identified. The results suggest that the diet containing WCR did not affect the major groups of bacteria, but stimulated the growth of L. reuteri-like species.

  15. The impact of date palm fruits and their component polyphenols, on gut microbial ecology, bacterial metabolites and colon cancer cell proliferation.

    Science.gov (United States)

    Eid, Noura; Enani, Sumia; Walton, Gemma; Corona, Giulia; Costabile, Adele; Gibson, Glenn; Rowland, Ian; Spencer, Jeremy P E

    2014-01-01

    The fruit of the date palm (Phoenix dactylifera L.) is a rich source of dietary fibre and polyphenols. We have investigated gut bacterial changes induced by the whole date fruit extract (digested date extract; DDE) and its polyphenol-rich extract (date polyphenol extract; DPE) using faecal, pH-controlled, mixed batch cultures mimicking the distal part of the human large intestine, and utilising an array of microbial group-specific 16S rRNA oligonucleotide probes. Fluorescence microscopic enumeration indicated that there was a significant increase in the growth of bifidobacteria in response to both treatments, whilst whole dates also increased bacteroides at 24 h and the total bacterial counts at later fermentation time points when compared with DPE alone. Bacterial metabolism of whole date fruit led to the production of SCFA, with acetate significantly increasing following bacterial incubation with DDE. In addition, the production of flavonoid aglycones (myricetin, luteolin, quercetin and apigenin) and the anthocyanidin petunidin in less than 1 h was also observed. Lastly, the potential of DDE, DPE and metabolites to inhibit Caco-2 cell growth was investigated, indicating that both were capable of potentially acting as antiproliferative agents in vitro, following a 48 h exposure. This potential to inhibit growth was reduced following fermentation. Together these data suggest that consumption of date fruits may enhance colon health by increasing beneficial bacterial growth and inhibiting the proliferation of colon cancer cells. This is an early suggestion that date intake by humans may aid in the maintenance of bowel health and even the reduction of colorectal cancer development.

  16. Staphylococcus aureus Colonization of the Mouse Gastrointestinal Tract Is Modulated by Wall Teichoic Acid, Capsule, and Surface Proteins.

    Directory of Open Access Journals (Sweden)

    Yoshiki Misawa

    2015-07-01

    Full Text Available Staphylococcus aureus colonizes the nose, throat, skin, and gastrointestinal (GI tract of humans. GI carriage of S. aureus is difficult to eradicate and has been shown to facilitate the transmission of the bacterium among individuals. Although staphylococcal colonization of the GI tract is asymptomatic, it increases the likelihood of infection, particularly skin and soft tissue infections caused by USA300 isolates. We established a mouse model of persistent S. aureus GI colonization and characterized the impact of selected surface antigens on colonization. In competition experiments, an acapsular mutant colonized better than the parental strain Newman, whereas mutants defective in sortase A and clumping factor A showed impaired ability to colonize the GI tract. Mutants lacking protein A, clumping factor B, poly-N-acetyl glucosamine, or SdrCDE showed no defect in colonization. An S. aureus wall teichoic acid (WTA mutant (ΔtagO failed to colonize the mouse nose or GI tract, and the tagO and clfA mutants showed reduced adherence in vitro to intestinal epithelial cells. The tagO mutant was recovered in lower numbers than the wild type strain in the murine stomach and duodenum 1 h after inoculation. This reduced fitness correlated with the in vitro susceptibility of the tagO mutant to bile salts, proteases, and a gut-associated defensin. Newman ΔtagO showed enhanced susceptibility to autolysis, and an autolysin (atl tagO double mutant abrogated this phenotype. However, the atl tagO mutant did not survive better in the mouse GI tract than the tagO mutant. Our results indicate that the failure of the tagO mutant to colonize the GI tract correlates with its poor adherence and susceptibility to bactericidal factors within the mouse gut, but not to enhanced activity of its major autolysin.

  17. Surface thermodynamics and adhesion forces governing bacterial transmission in contact lens related microbial keratitis

    NARCIS (Netherlands)

    Qu, Wenwen; Busscher, Henk J.; Hooymans, Johanna M. M.; van der Mei, Henny C.

    2011-01-01

    Contact lens induced microbial keratitis results from bacterial transmission from one surface to another. We investigated the adhesion forces of Pseudomonas aeruginosa, Staphylococci and Serratia to different contact lenses, lens cases and corneal surfaces using AFM, and applied a Weibull analysis

  18. Analysis of bacterial detachment from substratum surfaces by the passage of air-liquid interfaces

    NARCIS (Netherlands)

    Gomez-Suarez, C; Busscher, HJ; van der Mei, HC

    A theoretical analysis of the detachment of bacteria adhering to substratum surfaces upon the passage of an air-liquid interface is given, together with experimental results for bacterial detachment in the absence and presence of a conditioning film on different substratum surfaces. Bacteria

  19. Bacterial Colonization in the Marginal Region of Ceramic Restorations: Effects of Different Cement Removal Methods and Polishing.

    Science.gov (United States)

    Pereira, Smb; Anami, L C; Pereira, C A; Souza, Roa; Kantorski, K Z; Bottino, M A; Jorge, Aoc; Valandro, L F

    statistically influenced Ra (MBr, p=0.0019; Br, p=0.002; Photo-Expl, p=0.0262; Photo-SB, p=0.0196) when comparing the polished and unpolished groups. The MBr and MBr-Pol technique differed significantly for CFU/mL values (p=0.010). There was no significant difference in the amounts of biomass and biothickness comparing polished and unpolished groups and when all groups were compared (p>0.05). Different morphological patterns were observed (more regular surface for polished groups). We conclude that margin polishing after cementation of feldspar/pressed ceramic restorations is decisive for achieving smoother surfaces, as the excess cement around the edges can increase the surface roughness in these areas, influencing bacterial adhesion.

  20. Defensive remodeling: How bacterial surface properties and biofilm formation promote resistance to antimicrobial peptides.

    Science.gov (United States)

    Nuri, Reut; Shprung, Tal; Shai, Yechiel

    2015-11-01

    Multidrug resistance bacteria are a major concern worldwide. These pathogens cannot be treated with conventional antibiotics and thus alternative therapeutic agents are needed. Antimicrobial peptides (AMPs) are considered to be good candidates for this purpose. Most AMPs are short and positively charged amphipathic peptides, which are found in all known forms of life. AMPs are known to kill bacteria by binding to the negatively charged bacterial surface, and in most cases cause membrane disruption. Resistance toward AMPs can be developed, by modification of bacterial surface molecules, secretion of protective material and up-regulation or elimination of specific proteins. Because of the general mechanisms of attachment and action of AMPs, bacterial resistance to AMPs often involves biophysical and biochemical changes such as surface rigidity, cell wall thickness, surface charge, as well as membrane and cell wall modification. Here we focus on the biophysical, surface and surrounding changes that bacteria undergo in acquiring resistance to AMPs. In addition we discuss the question of whether bacterial resistance to administered AMPs might compromise our innate immunity to endogenous AMPs. This article is part of a Special Issue entitled: Bacterial Resistance to Antimicrobial Peptides. Copyright © 2015. Published by Elsevier B.V.

  1. Surface physical chemistry properties in coated bacterial cellulose membranes with calcium phosphate.

    Science.gov (United States)

    de Olyveira, Gabriel Molina; Basmaji, Pierre; Costa, Ligia Maria Manzine; Dos Santos, Márcio Luiz; Dos Santos Riccardi, Carla; Guastaldi, Fernando Pozzi Semeghini; Scarel-Caminaga, Raquel Mantuaneli; de Oliveira Capote, Ticiana Sidorenko; Pizoni, Elisabeth; Guastaldi, Antônio Carlos

    2017-06-01

    Bacterial cellulose has become established as a new biomaterial, and it can be used for medical applications. In addition, it has called attention due to the increasing interest in tissue engineering materials for wound care. In this work, the bacterial cellulose fermentation process was modified by the addition of chondroitin sulfate to the culture medium before the inoculation of the bacteria. The biomimetic process with heterogeneous calcium phosphate precipitation of biological interest was studied for the guided regeneration purposes on bacterial cellulose. FTIR results showed the incorporation of the chondroitin sulfate in the bacterial cellulose, SEM images confirmed the deposition of the calcium phosphate on the bacterial cellulose surface, XPS analysis showed a selective chemical group influences which change calcium phosphate deposition, besides, the calcium phosphate phase with different Ca/P ratios on bacterial cellulose surface influences wettability. XTT results concluded that these materials did not affect significantly in the cell viability, being non-cytotoxic. Thus, it was produced one biomaterial with the surface charge changes for calcium phosphate deposition, besides different wettability which builds new membranes for Guided Tissue Regeneration. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. [Submucosal bacterial abscesses of the ascending colon and liver associated with portal and superior mesenteric vein thrombosis due to Enterococcus faecalis infection: a case report].

    Science.gov (United States)

    Norimura, Daisuke; Takeshima, Fuminao; Satou, Yoshiaki; Nakagoe, Tohru; Ohnita, Ken; Isomoto, Hajime; Nakao, Kazuhiko

    2014-06-01

    A 72-year-old woman with diabetes mellitus was admitted with fever and general fatigue. Blood biochemistry showed elevated hepatic and biliary enzyme levels, abdominal computed tomography showed multiple liver abscesses with portal and superior mesenteric vein thrombosis, and total colonoscopy revealed a submucosal bacterial abscess in the ascending colon. The abscesses were determined to be associated with Enterococcus faecalis infection. The patient was treated conservatively with antibiotics (meropenem) and anticoagulants (warfarin), which led to a gradual amelioration of symptoms and resolution of thrombosis.

  3. Effect of four dental varnishes on the colonization of cariogenic bacteria on exposed sound root surfaces.

    Science.gov (United States)

    Ekenbäck, S B; Linder, L E; Lönnies, H

    2000-01-01

    The aim of this study was to evaluate the effect of four different dental varnishes on the colonization of mutans streptococci, total streptococci and lactobacilli on exposed sound root surfaces. Sixty-five individuals were randomly allotted to one of four groups for treatment with Cervitec((R) ) varnish containing 1% chlorhexidine and 1% thymol, a thymol varnish or one of two different fluoride varnishes, Fluor Protector and Duraphat. The varnish was applied to three buccal root surfaces in each patient at baseline and after 1 week. Dental plaque from the root surfaces was collected and analysed on four different occasions: at baseline, after 1 week, 1 month and 6 months. The Cervitec varnish caused a statistically significant reduction in the number of mutans streptococci over time. The reduction was significant at 1 week and 1 month relative to baseline. The numbers of total streptococci and lactobacilli were not significantly affected by treatment with Cervitec. No statistically significant difference over time was found for mutans streptococci, lactobacilli or total streptococci after treatment with the fluoride varnishes or the thymol varnish.

  4. Surface-Selective Preferential Production of Reactive Oxygen Species on Piezoelectric Ceramics for Bacterial Killing

    OpenAIRE

    Tan, Guoxin; Wang, Shuangying; Zhu, Ye; Zhou, Lei; Yu, Peng; Wang, Xiaolan; He, Tianrui; Chen, Junqi; Mao, Chuanbin; Ning, Chengyun

    2016-01-01

    Reactive oxygen species (ROS) can be used to kill bacterial cells, and thus the selective generation of ROS from material surfaces is an emerging direction in antibacterial material discovery. We found the polarization of piezoelectric ceramic causes the two sides of the disk to become positively and negatively charged, which translate into cathode and anode surfaces in an aqueous solution. Because of the microelectrolysis of water, ROS are preferentially formed on the cathode surface. Conseq...

  5. Electrochemical determination of the onset of bacterial surface adhesion

    Science.gov (United States)

    Jones, Akhenaton-Andrew; Buie, Cullen

    2017-11-01

    Microbial biofouling causes economic loss through corrosion and drag losses on ship hulls, and in oil and food distribution. Microorganisms interacting with surfaces under these open channel flows contend with high shear rates and active transport to the surface. The metallic surfaces they interact with carry charge at various potentials that are little addressed in literature. In this study we demonstrate that the Levich curve, chronoamperometry, and cyclic voltammetry in a rotating disk electrode are ideal for studying adhesion of microbes to metallic surfaces. We study the adhesion of Escherichia coli, Bacillus subtilis, and 1 μm silica microspheres over a 0.15 - 37.33 dynes .cm-2 or shear rates of 14.73 - 3727.28 s-1 range. Our results agree with literature on red blood cells in rotating disk electrodes, deposition rates from optical systems, and show that we can quantify changes in active electrode area by bacteria adhesion and protein secretion. These methods measure changes in area instead of mass, are more accurate than fluorescence microscopy, and apply to a larger range of problems than on-chip flow devices.

  6. Primary role of electron work function for evaluation of nanostructured titania implant surface against bacterial infection

    Energy Technology Data Exchange (ETDEWEB)

    Golda-Cepa, M., E-mail: golda@chemia.uj.edu.pl [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland); Syrek, K. [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland); Brzychczy-Wloch, M. [Department of Bacteriology, Microbial Ecology and Parasitology, Jagiellonian University Medical College, Czysta 18, 31-121 Krakow (Poland); Sulka, G.D. [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland); Kotarba, A., E-mail: kotarba@chemia.uj.edu.pl [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland)

    2016-09-01

    The electron work function as an essential descriptor for the evaluation of metal implant surfaces against bacterial infection is identified for the first time. Its validity is demonstrated on Staphylococcus aureus adhesion to nanostructured titania surfaces. The established correlation: work function–bacteria adhesion is of general importance since it can be used for direct evaluation of any electrically conductive implant surfaces. - Highlights: • The correlation between work function and bacteria adhesion was discovered. • The discovered correlation is rationalized in terms of electrostatic bacteria–surface repulsion. • The results provide basis for the simple evaluation of implant surfaces against infection.

  7. Understanding bacterial resistance to antimicrobial peptides: From the surface to deep inside.

    Science.gov (United States)

    Maria-Neto, Simone; de Almeida, Keyla Caroline; Macedo, Maria Ligia Rodrigues; Franco, Octávio Luiz

    2015-11-01

    Resistant bacterial infections are a major health problem in many parts of the world. The major commercial antibiotic classes often fail to combat common bacteria. Although antimicrobial peptides are able to control bacterial infections by interfering with microbial metabolism and physiological processes in several ways, a large number of cases of resistance to antibiotic peptide classes have also been reported. To gain a better understanding of the resistance process various technologies have been applied. Here we discuss multiple strategies by which bacteria could develop enhanced antimicrobial peptide resistance, focusing on sub-cellular regions from the surface to deep inside, evaluating bacterial membranes, cell walls and cytoplasmic metabolism. Moreover, some high-throughput methods for antimicrobial resistance detection and discrimination are also examined. This article is part of a Special Issue entitled: Bacterial Resistance to Antimicrobial Peptides. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Comparison of the effect of topical application of human milk and dry cord care on the bacterial colonization of umbilical cord in newborn infants

    Directory of Open Access Journals (Sweden)

    Fatemeh Abbaszadeh

    2014-04-01

    Full Text Available Background: Breast milk contains significant amounts of compounds that act as natural antimicrobial agents. This study was conducted to compare the effect of topical application of human milk and dry cord care on bacterial colonization in the umbilical cord of newborn infants. Methods: This clinical trial study was carried out on 174 infants in Kashan. The newborns were randomized to mother's milk group and dry cord care group from the birth. In group 1, the mother rubbed her own milk on the cord stump every 12 hours from 3 hours after birth to 2 days after the umbilical cord separation. In group 2, the mother was recommended not to use any material on the cord. Then, the cord samples were taken four times; 3hours after birth, at days 3 and 7, and 2 days after the umbilical cord separation. Results: The findings of the culture two days after umbilical cord separation indicated that low percentage of neonates in the breast milk (23.1% and dry cord care (28.8% groups had bacterial colonization. Moreover, no significant difference was found between the two groups in terms of growth of pathogenic organisms and normal flora of the skin (P>0.05. Conclusion: Given the low prevalence of pathogenic microorganisms in the two groups, it seems using breast milk and dry cord care are equally effective methods of taking care of umbilical cord.

  9. Hydration-controlled bacterial motility and dispersal on surfaces

    DEFF Research Database (Denmark)

    Dechesne, Arnaud; Wang, G.; Gulez, Gamze

    2010-01-01

    Flagellar motility, a mode of active motion shared by many prokaryotic species, is recognized as a key mechanism enabling population dispersal and resource acquisition in microbial communities living in marine, freshwater, and other liquid-replete habitats. By contrast, its role in variably...... resume motility in response to periodic increases in hydration. We propose a biophysical model that captures key effects of hydration and liquid-film thickness on individual cell velocity and use a simple roughness network model to simulate colony expansion. Model predictions match experimental results...... the costs associated with flagella synthesis and explain the sustained presence of flagellated prokaryotes in partially saturated habitats such as soil surfaces....

  10. [Can the urine dipstick be used in the diagnosis of urinary bacterial colonizations in a preoperative urological assessment?].

    Science.gov (United States)

    Cariou, G; El Basri, A; Cohen, J; Cortesse, A

    2016-04-01

    The use of the dipstick urinalysis has been validated for the diagnosis of symptomatic urinary infections, cystitis and pyelonephritis thanks to an excellent negative predictive value. For prostatitis, it is rather its positive predictive value that is interesting. The aim of this study is to validate its use in the screening of urinary colonizations in the preoperative assessment in urology. A monocentric prospective study was carried out for one year in 2011 comparing the data from the urine dipstick test with a fresh-voided midstream urinary examination and culture performed on the day of admission with the same urine sample in 598 asymptomatic patients programmed for a urological procedure. The gold standard to diagnose a microbiological-confirmed urinary tract infection or colonization was uropathogen growth of ≥10(3) colony-forming units per ml (cfu/mL) with or without leucocyturia. The study disclosed 5% of colonized patients. The urine dipstick test had a 65% sensitivity and a 97% negative predictive value. However, the low sensitivity of the urine dipstick test entailed 34% of false negatives. In spite of a good negative predictive value linked to a low prevalence of colonized patients (5%), the low sensitivity of the urine dipstick test entails a non-negligible number of false negatives. Its use as a single test of preoperative screening would expose colonized patients to the prospect of an operation, which seems to be unacceptable for some of them, notably endoscopic ones. 4. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  11. Bacterial Cell Surface Adsorption of Rare Earth Elements

    Science.gov (United States)

    Jiao, Y.; Park, D.; Reed, D.; Fujita, Y.; Yung, M.; Anderko, A.; Eslamimanesh, A.

    2015-12-01

    Rare earth elements (REE) play a critical role in many emerging clean energy technologies, including high-power magnets, wind turbines, solar panels, hybrid/electric vehicle batteries and lamp phosphors. In order to sustain demand for such technologies given current domestic REE shortages, there is a need to develop new approaches for ore processing/refining and recycling of REE-containing materials. To this end, we have developed a microbially-mediated bioadsorption strategy with application towards enrichment of REE from complex mixtures. Specifically, the bacterium Caulobacter crescentus was genetically engineered to display lanthanide binding tags (LBTs), short peptides that possess high affinity and specificity for rare earth elements, on its cell surface S-layer protein. Under optimal conditions, LBT-displayed cells adsorbed greater than 5-fold more REE than control cells lacking LBTs. Competition binding experiments with a selection of REEs demonstrated that our engineered cells could facilitate separation of light- from heavy- REE. Importantly, binding of REE onto our engineered strains was much more favorable compared to non-REE metals. Finally, REE bound to the cell surface could be stripped off using citrate, providing an effective and non-toxic REE recovery method. Together, this data highlights the potential of our approach for selective REE enrichment from REE containing mixtures.

  12. Biochemical characteristics and bacterial community structure of the sea surface microlayer in the South Pacific Ocean

    Directory of Open Access Journals (Sweden)

    I. Obernosterer

    2008-05-01

    Full Text Available The chemical and biological characteristics of the surface microlayer were determined during a transect across the South Pacific Ocean in October-December 2004. Concentrations of particulate organic carbon (1.3 to 7.6-fold and nitrogen (1.4 to 7-fold, and POC:PON ratios were consistently higher in the surface microlayer as compared to surface waters (5 m. The large variability in particulate organic matter enrichment was negatively correlated to wind speed. No enhanced concentrations of dissolved organic carbon were detectable in the surface microlayer as compared to 5 m, but chromophoric dissolved organic matter was markedly enriched (by 2 to 4-fold at all sites. Based on pigment analysis and cell counts, no consistent enrichment of any of the major components of the autotrophic and heterotrophic microbial community was detectable. CE-SSCP fingerprints and CARD FISH revealed that the bacterial communities present in the surface microlayer had close similarity (>76% to those in surface waters. By contrast, bacterial heterotrophic production (3H-leucine incorporation was consistently lower in the surface microlayer than in surface waters. By applying CARD-FISH and microautoradiography, we observed that Bacteroidetes and Gammaproteobacteria dominated leucine uptake in the surface microlayer, while in surface waters Bacteroidetes and Alphaproteobacteria were the major groups accounting for leucine incorporation. Our results demonstrate that the microbial community in the surface microlayer closely resembles that of the surface waters of the open ocean. Even a short residence in the surface microlayer influences leucine incorporation by different bacterial groups, probably as a response to the differences in the physical and chemical nature of the two layers.

  13. Surface properties of semi-synthetic enteric coating films: Opportunities to develop bio-based enteric coating films for colon- targeted delivery

    Science.gov (United States)

    This study investigated the surface properties of the semi-synthetic enteric coating materials for potential colon- targeted bioactive delivery. The enteric coating materials were produced by combining nanoscale resistant starch, pectin, and carboxymethylcellulose. The surface properties of the co...

  14. Effects of three approaches to standardized oral hygiene to reduce bacterial colonization and ventilator associated pneumonia in mechanically ventilated patients: a randomised control trial.

    Science.gov (United States)

    Berry, A M; Davidson, P M; Masters, J; Rolls, K; Ollerton, R

    2011-06-01

    Ventilator associated pneumonia remains an important concern in the intensive care unit (ICU). An increasing body of evidence shows that mortality and morbidity can be reduced by implementing a range of preventive strategies, including optimizing oral hygiene. The aim of this feasibility study was to test two oral hygiene strategies on the effects of microbial colonization of dental plaque with respiratory pathogens (primary outcome) and incidence of ventilator associated pneumonia (secondary outcome). A single blind randomised comparative study was conducted in a 20-bed adult intensive care unit in a university hospital. Patients with an expected duration of mechanical ventilation more than 48 h were eligible. Patients were randomised to one of three study regimens (Group A control, second hourly oral rinse with sterile water, Group B sodium bicarbonate mouth wash second hourly, and Group C twice daily irrigations with chlorhexidine 0.2% aqueous oral rinse and second hourly irrigations with sterile water). All study options included cleaning with a toothbrush and non foaming toothpaste. Data from a total of 109 patients were analyzed. Group A 43, Group B 33 and Group C 33 (mean age: 58 ± 17 years, simplified acute physiology score II: 44 ± 14 points). On admission no significant differences were found between groups for all clinical data. While Group B showed a greater trend to reduction in bacterial colonization no significant differences could be demonstrated at Day 4 of admission (p=0.302). The incidence of ventilator associated pneumonia was evenly spread between Groups B and C (5%) while Group A was only 1%. While a number of studies have advocated the use of various mouth rinses in reducing colonization of dental plaque a standardized oral hygiene protocol which includes the use of mechanical cleaning with a toothbrush may be a factor in the reduction of colonization of dental plaque with respiratory pathogens. This feasibility study provides data to

  15. Characterization of bacteria in biopsies of colon and stools by high throughput sequencing of the V2 region of bacterial 16S rRNA gene in human.

    Science.gov (United States)

    Momozawa, Yukihide; Deffontaine, Valérie; Louis, Edouard; Medrano, Juan F

    2011-02-10

    The characterization of the human intestinal microflora and their interactions with the host have been identified as key components in the study of intestinal disorders such as inflammatory bowel diseases. High-throughput sequencing has enabled culture-independent studies to deeply analyze bacteria in the gut. It is possible with this technology to systematically analyze links between microbes and the genetic constitution of the host, such as DNA polymorphisms and methylation, and gene expression. In this study the V2 region of the bacterial 16S ribosomal RNA (rRNA) gene using 454 pyrosequencing from seven anatomic regions of human colon and two types of stool specimens were analyzed. The study examined the number of reads needed to ascertain differences between samples, the effect of DNA extraction procedures and PCR reproducibility, and differences between biopsies and stools in order to design a large scale systematic analysis of gut microbes. It was shown (1) that sequence coverage lower than 1,000 reads influenced quantitative and qualitative differences between samples measured by UniFrac distances. Distances between samples became stable after 1,000 reads. (2) Difference of extracted bacteria was observed between the two DNA extraction methods. In particular, Firmicutes Bacilli were not extracted well by one method. (3) Quantitative and qualitative difference in bacteria from ileum to rectum colon were not observed, but there was a significant positive trend between distances within colon and quantitative differences. Between sample type, biopsies or stools, quantitative and qualitative differences were observed. Results of human colonic bacteria analyzed using high-throughput sequencing were highly dependent on the experimental design, especially the number of sequence reads, DNA extraction method, and sample type.

  16. Characterization of bacteria in biopsies of colon and stools by high throughput sequencing of the V2 region of bacterial 16S rRNA gene in human.

    Directory of Open Access Journals (Sweden)

    Yukihide Momozawa

    Full Text Available BACKGROUND: The characterization of the human intestinal microflora and their interactions with the host have been identified as key components in the study of intestinal disorders such as inflammatory bowel diseases. High-throughput sequencing has enabled culture-independent studies to deeply analyze bacteria in the gut. It is possible with this technology to systematically analyze links between microbes and the genetic constitution of the host, such as DNA polymorphisms and methylation, and gene expression. METHODS AND FINDINGS: In this study the V2 region of the bacterial 16S ribosomal RNA (rRNA gene using 454 pyrosequencing from seven anatomic regions of human colon and two types of stool specimens were analyzed. The study examined the number of reads needed to ascertain differences between samples, the effect of DNA extraction procedures and PCR reproducibility, and differences between biopsies and stools in order to design a large scale systematic analysis of gut microbes. It was shown (1 that sequence coverage lower than 1,000 reads influenced quantitative and qualitative differences between samples measured by UniFrac distances. Distances between samples became stable after 1,000 reads. (2 Difference of extracted bacteria was observed between the two DNA extraction methods. In particular, Firmicutes Bacilli were not extracted well by one method. (3 Quantitative and qualitative difference in bacteria from ileum to rectum colon were not observed, but there was a significant positive trend between distances within colon and quantitative differences. Between sample type, biopsies or stools, quantitative and qualitative differences were observed. CONCLUSIONS: Results of human colonic bacteria analyzed using high-throughput sequencing were highly dependent on the experimental design, especially the number of sequence reads, DNA extraction method, and sample type.

  17. Surface-Selective Preferential Production of Reactive Oxygen Species on Piezoelectric Ceramics for Bacterial Killing.

    Science.gov (United States)

    Tan, Guoxin; Wang, Shuangying; Zhu, Ye; Zhou, Lei; Yu, Peng; Wang, Xiaolan; He, Tianrui; Chen, Junqi; Mao, Chuanbin; Ning, Chengyun

    2016-09-21

    Reactive oxygen species (ROS) can be used to kill bacterial cells, and thus the selective generation of ROS from material surfaces is an emerging direction in antibacterial material discovery. We found the polarization of piezoelectric ceramic causes the two sides of the disk to become positively and negatively charged, which translate into cathode and anode surfaces in an aqueous solution. Because of the microelectrolysis of water, ROS are preferentially formed on the cathode surface. Consequently, the bacteria are selectively killed on the cathode surface. However, the cell experiment suggested that the level of ROS is safe for normal mammalian cells.

  18. Bacterial Adhesion and Surface Roughness for Different Clinical Techniques for Acrylic Polymethyl Methacrylate.

    Science.gov (United States)

    Dantas, Lucas Costa de Medeiros; da Silva-Neto, João Paulo; Dantas, Talita Souza; Naves, Lucas Zago; das Neves, Flávio Domingues; da Mota, Adérito Soares

    2016-01-01

    This study sought to assess the effect of different surface finishing and polishing protocols on the surface roughness and bacterial adhesion (S. sanguinis) to polymethyl methacrylates (PMMA). Fifty specimens were divided into 5 groups (n = 10) according to their fabrication method and surface finishing protocol: LP (3 : 1 ratio and laboratory polishing), NF (Nealon technique and finishing), NP (Nealon technique and manual polishing), MF (3 : 1 ratio and manual finishing), and MP (3 : 1 ratio and manual polishing). For each group, five specimens were submitted to bacterial adhesion tests and analyzed by scanning electron microscopy (SEM). Two additional specimens were subjected to surface topography analysis by SEM and the remaining three specimens were subjected to surface roughness measurements. Data were compared by one-way ANOVA. The mean bacterial counts were as follows: NF, 19.6 ± 3.05; MP, 5.36 ± 2.08; NP, 4.96 ± 1.93; MF, 7.36 ± 2.45; and LP, 1.56 ± 0.62 (CFU). The mean surface roughness values were as follows: NF, 3.23 ± 0.15; MP, 0.52 ± 0.05; NP, 0.60 ± 0.08; MF, 2.69 ± 0.12; and LP, 0.07 ± 0.02 (μm). A reduction in the surface roughness was observed to be directly related to a decrease in bacterial adhesion. It was verified that the laboratory processing of PMMA might decrease the surface roughness and consequently the adhesion of S. sanguinis to this material.

  19. Biomimetic Bacterial Identification Platform Based on Thermal Wave Transport Analysis (TWTA) through Surface-Imprinted Polymers.

    Science.gov (United States)

    Steen Redeker, Erik; Eersels, Kasper; Akkermans, Onno; Royakkers, Jeroen; Dyson, Simba; Nurekeyeva, Kunya; Ferrando, Beniamino; Cornelis, Peter; Peeters, Marloes; Wagner, Patrick; Diliën, Hanne; van Grinsven, Bart; Cleij, Thomas Jan

    2017-05-12

    This paper introduces a novel bacterial identification assay based on thermal wave analysis through surface-imprinted polymers (SIPs). Aluminum chips are coated with SIPs, serving as synthetic cell receptors that have been combined previously with the heat-transfer method (HTM) for the selective detection of bacteria. In this work, the concept of bacterial identification is extended toward the detection of nine different bacterial species. In addition, a novel sensing approach, thermal wave transport analysis (TWTA), is introduced, which analyzes the propagation of a thermal wave through a functional interface. The results presented here demonstrate that bacterial rebinding to the SIP layer resulted in a measurable phase shift in the propagated wave, which is most pronounced at a frequency of 0.03 Hz. In this way, the sensor is able to selectively distinguish between the different bacterial species used in this study. Furthermore, a dose-response curve was constructed to determine a limit of detection of 1 × 10 4 CFU mL -1 , indicating that TWTA is advantageous over HTM in terms of sensitivity and response time. Additionally, the limit of selectivity of the sensor was tested in a mixed bacterial solution, containing the target species in the presence of a 99-fold excess of competitor species. Finally, a first application for the sensor in terms of infection diagnosis is presented, revealing that the platform is able to detect bacteria in clinically relevant concentrations as low as 3 × 10 4 CFU mL -1 in spiked urine samples.

  20. Colonic epithelial cell expression of ICAM-1 relates to loss of surface continuity

    DEFF Research Database (Denmark)

    Vainer, Ben; Horn, Thomas; Nielsen, Ole Haagen

    2006-01-01

    OBJECTIVE: Intercellular adhesion molecule-1 (ICAM-1) is important in ulcerative colitis (UC) by mediating the arrest and further migration of neutrophils. In vitro studies have shown that colonocytes from chronically inflamed colon and cultured colon cancer cells are capable of expressing ICAM-1...

  1. Status of bacterial colonization in teeth associated with different types of pulpal and periradicular disease: A scanning electron microscopy analysis

    Directory of Open Access Journals (Sweden)

    Yan-Hua Huang

    2015-03-01

    Conclusion: Bacterial infection was lighter in the root canals with pulpitis than in those with apical periodontitis, which might require special considerations regarding different stages of pulp and periapical pathology in root canal treatment.

  2. Bacterial Colonization of the Implant-Abutment Interface (IAI) of Dental Implants with a Sloped Marginal Design: An in-vitro Study.

    Science.gov (United States)

    Koutouzis, Theofilos; Gadalla, Hana; Lundgren, Tord

    2016-02-01

    The aim of this study is to utilize an in vitro dynamic loading model to assess the potential risk of bacterial invasion into the Implant Abutment Interface (IAI) microgap of dental implants with sloped marginal design. Forty implants were divided into two groups (n = 20 per group) based on implant marginal design. Group 1 was comprised of implants with Morse-taper connection and conventional marginal design that connected to titanium abutments. Group 2 was comprised of implants with Morse-taper connection and sloped marginal design that connected to titanium abutments. The specimens were immersed in a bacterial solution of E. coli and loaded with 500,000 cycles of 160N using a chewing simulator. Following disconnection of fixtures and abutments, microbial samples were taken from the threaded portion of the abutment, plated and cultured under appropriate conditions. Ten out of twenty implants of Group 1 and eight out of twenty implants of Group 2 had IAI microgaps colonized by E. Coli. There was not a statistically significant difference in the mean number of E. Coli CFU detected between implants of Group 1 (mean 19.2, SD 23.6) and Group 2 (mean 12.5, SD18.9) (p > .05). The present study demonstrated that implants with a sloped marginal design exhibited similar risk for bacterial invasion into the IAI microgap under in vitro dynamic loading conditions compared to implants with conventional marginal design. © 2015 Wiley Periodicals, Inc.

  3. Light structures phototroph, bacterial and fungal communities at the soil surface.

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    Lawrence O Davies

    Full Text Available The upper few millimeters of soil harbour photosynthetic microbial communities that are structurally distinct from those of underlying bulk soil due to the presence of light. Previous studies in arid zones have demonstrated functional importance of these communities in reducing soil erosion, and enhancing carbon and nitrogen fixation. Despite being widely distributed, comparative understanding of the biodiversity of the soil surface and underlying soil is lacking, particularly in temperate zones. We investigated the establishment of soil surface communities on pasture soil in microcosms exposed to light or dark conditions, focusing on changes in phototroph, bacterial and fungal communities at the soil surface (0-3 mm and bulk soil (3-12 mm using ribosomal marker gene analyses. Microbial community structure changed with time and structurally similar phototrophic communities were found at the soil surface and in bulk soil in the light exposed microcosms suggesting that light can influence phototroph community structure even in the underlying bulk soil. 454 pyrosequencing showed a significant selection for diazotrophic cyanobacteria such as Nostoc punctiforme and Anabaena spp., in addition to the green alga Scenedesmus obliquus. The soil surface also harboured distinct heterotrophic bacterial and fungal communities in the presence of light, in particular, the selection for the phylum Firmicutes. However, these light driven changes in bacterial community structure did not extend to the underlying soil suggesting a discrete zone of influence, analogous to the rhizosphere.

  4. Multi-functional and redundant roles of Borrelia burgdorferi outer surface proteins in tissue adhesion, colonization, and complement evasion.

    Directory of Open Access Journals (Sweden)

    Jennifer A Caine

    2016-10-01

    Full Text Available Borrelia burgdorferi is the causative agent of Lyme disease in the U.S., with at least 25,000 cases reported to the CDC each year. B. burgdorferi is thought to enter and exit the bloodstream to achieve rapid dissemination to distal tissue sites during infection. Travel through the bloodstream requires evasion of immune surveillance and pathogen clearance in the host, a process at which B. burgdorferi is adept. B. burgdorferi encodes greater than 19 adhesive outer surface proteins many of which have been found to bind to host cells or components of the extracellular matrix. Several others bind to host complement regulatory factors, in vitro. Production of many of these adhesive proteins is tightly regulated by environmental cues, and some have been shown to aid in vascular interactions and tissue colonization, as well as survival in the blood, in vivo. Recent work has described multifaceted and redundant roles of B. burgdorferi outer surface proteins in complement component interactions and tissue targeted adhesion and colonization, distinct from their previously identified in vitro binding capabilities. Recent insights into the multifunctional roles of previously well characterized outer surface proteins such as BBK32, DbpA, CspA, and OspC have changed the way we think about the surface proteome of these organisms during the tick-mammal lifecycle. With the combination of new and old in vivo models and in vitro techniques, the field has identified distinct ligand binding domains on BBK32 and DbpA that afford tissue colonization or blood survival to B. burgdorferi. In this review we describe the multifunctional and redundant roles of many adhesive outer surface proteins of B. burgdorferi in tissue adhesion, colonization, and bloodstream survival that, together, promote the survival of Borrelia spp. throughout maintenance in their multi-host lifestyle.

  5. Xylo-oligosaccharides and inulin affect genotoxicity and bacterial populations differently in a human colonic simulator challenged with soy protein

    DEFF Research Database (Denmark)

    Christophersen, C. T.; Petersen, Anne; Licht, Tine Rask

    2013-01-01

    High dietary intakes of some protein sources, including soy protein, can increase colonic DNA damage in animals, whereas some carbohydrates attenuate this. We investigated whether inulin and xylo-oligosaccharides (XOS) could be protective against DNA strand breaks by adding them to a human colonic...... cornstarch for 10 day followed by soy protein with 1% XOS or 1% inulin for 10 day. Inulin did not alter genotoxicity but XOS significantly reduced PV genotoxicity and increased DV genotoxicity. Inulin and XOS significantly increased butyrate concentration in the DV but not PV. Numbers of the key butyrate......-producing bacterium Faecalibacterium prausnitzii were significantly increased in the PV and DV by inulin but significantly decreased by XOS in both vessels. Other bacteria examined were also significantly impacted by the carbohydrate treatments or by the vessel (i.e., pH). There was a significant overall inverse...

  6. Effects of Tylosin on Bacterial Mucolysis, Clostridium perfringens Colonization, and Intestinal Barrier Function in a Chick Model of Necrotic Enteritis

    Science.gov (United States)

    Collier, C. T.; van der Klis, J. D.; Deplancke, B.; Anderson, D. B.; Gaskins, H. R.

    2003-01-01

    Necrotic enteritis (NE) is a worldwide poultry disease caused by the alpha toxin-producing bacterium Clostridium perfringens. Disease risk factors include concurrent coccidial infection and the dietary use of cereal grains high in nonstarch polysaccharides (NSP), such as wheat, barley, rye, and oats. Outbreaks of NE can be prevented or treated by the use of in-feed antibiotics. However, the current debate regarding the prophylactic use of antibiotics in animal diets necessitates a better understanding of factors that influence intestinal colonization by C. perfringens as well as the pathophysiological consequences of its growth. We report a study with a chick model of NE, which used molecular (16S rRNA gene [16S rDNA]) and culture-based microbiological techniques to investigate the impact of the macrolide antibiotic tylosin phosphate (100 ppm) and a dietary NSP (pectin) on the community structure of the small intestinal microbiota relative to colonization by C. perfringens. The effects of tylosin and pectin on mucolytic activity of the microbiota and C. perfringens colonization and their relationship to pathological indices of NE were of particular interest. The data demonstrate that tylosin reduced the percentage of mucolytic bacteria in general and the concentration of C. perfringens in particular, and these responses correlated in a temporal fashion with a reduction in the occurrence of NE lesions and an improvement in barrier function. The presence of pectin did not significantly affect the variables measured. Thus, it appears that tylosin can control NE through its modulation of C. perfringens colonization and the mucolytic activity of the intestinal microbiota. PMID:14506046

  7. Analysis of Bacterial Cell Surface Chemical Composition Using Cryogenic X-Ray Photoelectron Spectroscopy.

    Science.gov (United States)

    Ramstedt, Madeleine; Shchukarev, Andrey

    2016-01-01

    This chapter describes a method for measuring the average surface chemical composition with respect to lipids, polysaccharides, and peptides (protein + peptidoglycan) for the outer part of the bacterial cell wall. Bacterial cultures grown over night are washed with a buffer or saline at controlled pH. The analysis is done on fast-frozen bacterial cell pellets obtained after centrifugation, and the analysis requires access to X-ray photoelectron spectroscopy instrumentation that can perform analyses at cryogenic temperatures (for example using liquid nitrogen). The method can be used to monitor changes in the cell wall composition following environmental stimuli or genetic mutations. The data obtained originate from the outermost part of the cell wall. Thus, it is expected that for gram-negative bacteria only the outer membrane and part of the periplasmic peptidoglycan layer is probed during analysis, and for gram-positive bacteria only the top nanometers of the peptidoglycan layer of the cell wall is monitored.

  8. The influence of Lactobacillus rhamnosus LC705 together with Propionibacterium freudenreichii ssp. shermanii JS on potentially carcinogenic bacterial activity in human colon.

    Science.gov (United States)

    Hatakka, Katja; Holma, Reetta; El-Nezami, Hani; Suomalainen, Tarja; Kuisma, Minna; Saxelin, Maija; Poussa, Tuija; Mykkänen, Hannu; Korpela, Riitta

    2008-12-10

    The bacterial enzymes beta-glucosidase, beta-glucuronidase, and urease may contribute to the development of colon cancer by generating carcinogens. A reduction in the activity of these enzymes by certain lactic acid bacteria is considered to be beneficial. This study examined fecal beta-glucosidase, beta-glucuronidase, and urease activities during administration of Lactobacillus rhamnosus LC705 (LC705) together with Propionibacterium freudenreichii ssp shermanii JS (PJS). Thirty-eight healthy men participated in this randomized, double-blind, placebo-controlled, two-period crossover study with treatment periods of 4 weeks. Subjects consumed daily bacterial or placebo capsules. Bacterial capsules contained viable LC705 and PJS (2x10(10) CFU of each strain daily). The activities of beta-glucosidase, beta-glucuronidase and urease, recovery of LC705 and PJS, and counts of total lactobacilli and propionibacteria were determined from feces. The mean fecal counts of total lactobacilli and propionibacteria as well as strains LC705 and PJS were significantly increased during the administration of bacteria (3.5-, 13-, 80- and 11-fold, respectively). beta-glucosidase activity decreased by 10% (P=0.18) and urease activity by 13% (P=0.16) during bacterial supplementation versus placebo. The change in beta-glucosidase activity was negatively correlated with the change in propionibacteria counts (R=-0.350, P=0.039), being -2.68 versus 0.94 nmol/min/mg protein in subjects with increased and unchanged/decreased propionibacteria, respectively (P=0.003). To conclude, the administration of LC705 and PJS was followed by an increase in the fecal counts of lactobacilli and propionibacteria and a decrease in the activity of beta-glucosidase with increasing counts of propionibacteria.

  9. Differences in visceral fat and fat bacterial colonization between ulcerative colitis and Crohn's disease. An in vivo and in vitro study.

    Directory of Open Access Journals (Sweden)

    Alessandra Zulian

    Full Text Available Crohn's disease (CD is notably characterized by the expansion of visceral fat with small adipocytes expressing a high proportion of anti-inflammatory genes. Conversely, visceral fat depots in ulcerative colitis (UC patients have never been characterized. Our study aims were a to compare adipocyte morphology and gene expression profile and bacterial translocation in omental (OM and mesenteric (MES adipose tissue of patients with UC and CD, and b to investigate the effect of bacterial infection on adipocyte proliferation in vitro. Specimens of OM and MES were collected from 11 UC and 11 CD patients, processed and examined by light microscopy. Gene expression profiles were evaluated in adipocytes isolated from visceral adipose tissue using microarray and RTqPCR validations. Bacteria within adipose tissue were immuno-detected by confocal scanning laser microscopy. Adipocytes were incubated with Enterococcus faecalis and cells counted after 24 h. Morphology and molecular profile of OM and MES revealed that UC adipose tissue is less inflamed than CD adipose tissue. Genes linked to inflammation, bacterial response, chemotaxis and angiogenesis were down-regulated in adipocytes from UC compared to CD, whereas genes related to metallothioneins, apoptosis pathways and growth factor binding were up-regulated. A dense perinuclear positivity for Enterococcus faecalis was detected in visceral adipocytes from CD, whereas positivity was weak in UC. In vitro bacterial infection was associated with a five-fold increase in the proliferation rate of OM preadipocytes. Compared to UC, visceral adipose tissue from CD is more inflamed and more colonized by intestinal bacteria, which increase adipocyte proliferation. The influence of bacteria stored within adipocytes on the clinical course of IBD warrants further investigations.

  10. Mechanism of cell integration on biomaterial implant surfaces in the presence of bacterial contamination.

    Science.gov (United States)

    Yue, Chongxia; van der Mei, Henny C; Kuijer, Roel; Busscher, Henk J; Rochford, Edward T J

    2015-11-01

    Bacterial contamination during biomaterial implantation is often unavoidable, yielding a combat between cells and bacteria. Here we aim to determine the modulatory function of bacterial components on stem-cell, fibroblast, and osteoblast adhesion to a titanium alloy, including the role of toll-like-receptors (TLRs). Presence of heat-sacrificed Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, or Pseudomonas aeruginosa induced dose and cell-type dependent responses. Stem-cells were most sensitive to bacterial presence, demonstrating decreased adhesion number yet increased adhesion effort with a relatively large focal adhesion contact area. Blocking TLRs had no effect on stem-cell adhesion in presence of S. aureus, but blocking both TLR2 and TLR4 induced an increased adhesion effort in presence of E. coli. Neither lipopolysaccharide, lipoteichoic acid, nor bacterial DNA provoked the same cell response as did whole bacteria. Herewith we suggest a new mechanism as to how biomaterials are integrated by cells despite the unavoidable presence of bacterial contamination. Stimulation of host cell integration of implant surfaces may open a new window to design new biomaterials with enhanced healing, thereby reducing the risk of biomaterial-associated infection of both "hardware-based" implants as well as of tissue-engineered constructs, known to suffer from similarly high infection risks as currently prevailing in "hardware-based" implants. © 2015 Wiley Periodicals, Inc.

  11. Colon cancer

    Science.gov (United States)

    Colorectal cancer; Cancer - colon; Rectal cancer; Cancer - rectum; Adenocarcinoma - colon; Colon - adenocarcinoma; Colon carcinoma ... eat may play a role in getting colon cancer. Colon cancer may be linked to a high-fat, ...

  12. Bacterial stimuli activate nitric oxide colonic mucosal production in diverticular disease. Protective effects of L. casei DG® (Lactobacillus paracasei CNCM I-1572).

    Science.gov (United States)

    Turco, Fabio; Andreozzi, Paolo; Palumbo, Ilaria; Zito, Francesco Paolo; Cargiolli, Martina; Fiore, Walter; Gennarelli, Nicola; De Palma, Giovanni Domenico; Sarnelli, Giovanni; Cuomo, Rosario

    2017-08-01

    Micro-inflammation and changes in gut microbiota may play a role in the pathogenesis of diverticular disease (DD). The objective of this article is to evaluate the expression of nitric oxide (NO)-related mediators and S100B in colonic mucosa of patients with DD in an ex vivo model of bacterial infection. Intestinal biopsies obtained from patients with diverticulosis, symptomatic uncomplicated diverticular disease (SUDD) and SUDD with previous acute diverticulitis (SUDD+AD) were stimulated with the probiotic L. casei DG® (LCDG) and/or the pathogen enteroinvasive Escherichia coli (EIEC). S100B, NO release and iNOS expression were then evaluated. Basal iNOS expression was significantly increased in SUDD and SUDD+AD patients. Basal NO expression was significantly increased in SUDD+AD. No differences in S100B release were found. In all groups, iNOS expression was significantly increased by EIEC and reduced by LCDG. In all groups, except for SUDD+AD, EIEC significantly increased NO release, whereas no increase was observed when LCDG was added to biopsies. EIEC did not induce significant changes in S100B release. Colonic mucosa of patients with DD is characterized by a different reactivity toward pathogenic stimuli. LCDG plays a role in counteracting the pro-inflammatory effects exerted by EIEC, suggesting a beneficial role of this probiotic in DD.

  13. Differential effect of early antibiotic intervention on bacterial fermentation patterns and mucosal gene expression in the colon of pigs under diets with different protein levels.

    Science.gov (United States)

    Zhang, Chuanjian; Yu, Miao; Yang, Yuxiang; Mu, Chunlong; Su, Yong; Zhu, Weiyun

    2017-03-01

    The study aimed to evaluate the effects of early antibiotic intervention (EAI) on bacterial fermentation patterns and mucosal immune markers in the colon of pigs with different protein level diets. Eighteen litters of piglets at day (d) 7 were fed creep feed without or with growth promoting antibiotics until d 42. At d 42, pigs within each group were further randomly assigned to a normal- or low-crude protein (CP) diet. At d 77 and d 120, five pigs per group were slaughtered for analyzing colonic bacteria, metabolites, and mucosal gene expressions. Results showed that low-CP diet increased propionate and butyrate concentrations at d 77 but reduced ammonia and phenol concentrations (P fermentation and gene expressions of pro-inflammatory cytokines. Low-CP diet markedly reduced protein fermentation, modified microbial communities, and down-regulated gene expressions of pro-inflammatory cytokines possibly via down-regulating TLR4-MyD88-NF-κB signaling pathway.

  14. Composition of the bacterial community in the gut of the pine engraver, Ips pini (Say) (Coloptera) colonizing red pine

    Science.gov (United States)

    Italo Jr. Delalibera; Archana Vasanthakumar; Benjamin J. Burwitz; Patrick D. Schloss; Kier D. Klepzig; Jo Handelsman; Kenneth F. Raffa

    2007-01-01

    The gut bacterial community of a bark beetle, the pine engraver Ips pini (Say), was characterized using culture-dependent and culture-independent methods. Bacteria from individual guts of larvae, pupae and adults were cultured and DNA was extracted from samples of pooled larval guts. Analysis of 16S rRNA gene sequences amplified directly from the gut...

  15. The oral bacterial microbiome of occlusal surfaces in children and its association with diet and caries

    Science.gov (United States)

    Azcarate-Peril, Maria Andrea; Cadenas, Maria Belen; Butz, Natasha; Paster, Bruce J.; Chen, Tsute; Bair, Eric

    2017-01-01

    Dental caries is the most prevalent disease in humans globally. Efforts to control it have been invigorated by an increasing knowledge of the oral microbiome composition. This study aimed to evaluate the bacterial diversity in occlusal biofilms and its relationship with clinical surface diagnosis and dietary habits. Anamneses were recorded from thirteen 12-year-old children. Biofilm samples collected from occlusal surfaces of 46 permanent second molars were analyzed by 16S rRNA amplicon sequencing combined with the BLASTN-based search algorithm for species identification. The overall mean decayed, missing and filled surfaces modified index [DMFSm Index, including active white spot lesions (AWSL)] value was 8.77±7.47. Biofilm communities were highly polymicrobial collectively, representing 10 bacterial phyla, 25 classes, 29 orders, 58 families, 107 genera, 723 species. Streptococcus sp_Oral_Taxon_065, Corynebacterium matruchotii, Actinomyces viscosus, Actinomyces sp_Oral_Taxon_175, Actinomyces sp_Oral_Taxon_178, Actinomyces sp_Oral_Taxon_877, Prevotella nigrescens, Dialister micraerophilus, Eubacterium_XI G 1 infirmum were more abundant among surfaces with AWSL, and Streptococcus gordonii, Streptococcus sp._Oral_Taxon_058, Enterobacter sp._str._638 Streptococcus australis, Yersinia mollaretii, Enterobacter cloacae, Streptococcus sp._Oral_Taxon_71, Streptococcus sp._Oral_Taxon_F11, Centipeda sp._Oral_Taxon_D18 were more abundant among sound surfaces. Streptococcus mutans was detected on all surfaces in all patients, while Streptococcus sobrinus was detected only in three patients (mean relative abundances 7.1% and 0.6%, respectively). Neither species differentiated healthy from diseased sites. Diets of nine of the subjects were scored as high in fermentable carbohydrates (≧2X/day between meals). A direct association between relative abundances of bacteria and carbohydrate consumption was observed among 18 species. High consumption of fermentable carbohydrates and

  16. Effect of different finishing techniques for restorative materials on surface roughness and bacterial adhesion.

    Science.gov (United States)

    Aykent, Filiz; Yondem, Isa; Ozyesil, Atilla G; Gunal, Solen K; Avunduk, Mustafa C; Ozkan, Semiha

    2010-04-01

    The formation of biofilm and bacterial accumulation on dental materials may lead to the development of gingival inflammation and secondary caries. The purpose of this study was to examine the effect of different surface finishing and polishing methods on surface roughness and the adhesion of S. mutans bacteria to 2 new-generation indirect composite resins, 1 direct composite resin, and 1 ceramic material. Forty specimens (10 x 10 x 2 mm) of each material, indirect composite resins (SR Adoro, Estenia), direct composite resin (Tetric), and a ceramic material (VITABLOCS Mark II), were fabricated. Specimens were divided into 4 groups (n=10) that were treated with 1 of the following 4 surface finishing techniques: diamond rotary cutting instrument, sandpaper discs (Sof-Lex), silicone-carbide rubber points (Shofu), or a felt wheel with diamond paste. Surface roughness was measured with a profilometer. Test specimens were covered with artificial saliva and mucin to produce pellicle. Bacterial suspension (10(9) CFU/ml) was then added to the pellicle-coated specimens, and bacterial adhesion was determined using a confocal laser microscope and image analyzing program. Data were analyzed with 2-way ANOVA, followed by Tukey HSD test, Pearson correlation, and regression analysis (alpha=.05). The highest surface roughness values were recorded in SR Adoro and diamond rotary cutting instrument groups. The lowest vital S. mutans adhesion was seen in the ceramic group and in SR Adoro indirect composite resin (Padhesion to indirect composite resin materials differed from that to ceramic material after surface treatments. A positive correlation was observed between surface roughness and the vital S. mutans adhesion. Copyright 2010 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

  17. Crystalline Bacterial Surface Layer (S-Layer) Opens Golden Opportunities for Nanobiotechnology in Textiles.

    Science.gov (United States)

    Asadi, Narges; Chand, Nima; Rassa, Mehdi

    2015-12-01

    This study focuses on the successful recrystallization of bacterial S-layer arrays of the Lactobacillus acidophilus ATCC 4356 at textile surfaces to create a novel method and material. Optimum bacterial growth was obtained at approximately 45 °C, pH 5.0, and 14 h pi. The cells were resuspended in guanidine hydrochloride and the 43 kDa S-protein was dialyzed and purified. The optimum reassembly on the polypropylene fabric surface in terms of scanning electron microscopy (SEM), reflectance, and uniformity (spectrophotometry) was obtained at 30 °C, pH 5.0 for 30 minutes in the presence of 2 gr/l (liquor ratio; 1:40) of the S-protein. Overall, our data showed that the functional aspects and specialty applications of the fabric would be very attractive for the textile and related sciences, and result in advanced technical textiles.

  18. Honey bees avoid nectar colonized by three bacterial species, but not by a yeast species, isolated from the bee gut.

    Science.gov (United States)

    Good, Ashley P; Gauthier, Marie-Pierre L; Vannette, Rachel L; Fukami, Tadashi

    2014-01-01

    The gut microflora of the honey bee, Apis mellifera, is receiving increasing attention as a potential determinant of the bees' health and their efficacy as pollinators. Studies have focused primarily on the microbial taxa that appear numerically dominant in the bee gut, with the assumption that the dominant status suggests their potential importance to the bees' health. However, numerically minor taxa might also influence the bees' efficacy as pollinators, particularly if they are not only present in the gut, but also capable of growing in floral nectar and altering its chemical properties. Nonetheless, it is not well understood whether honey bees have any feeding preference for or against nectar colonized by specific microbial species. To test whether bees exhibit a preference, we conducted a series of field experiments at an apiary using synthetic nectar inoculated with specific species of bacteria or yeast that had been isolated from the bee gut, but are considered minor components of the gut microflora. These species had also been found in floral nectar. Our results indicated that honey bees avoided nectar colonized by the bacteria Asaia astilbes, Erwinia tasmaniensis, and Lactobacillus kunkeei, whereas the yeast Metschnikowia reukaufii did not affect the feeding preference of the insects. Our results also indicated that avoidance of bacteria-colonized nectar was caused not by the presence of the bacteria per se, but by the chemical changes to nectar made by the bacteria. These findings suggest that gut microbes may not only affect the bees' health as symbionts, but that some of the microbes may possibly affect the efficacy of A. mellifera as pollinators by altering nectar chemistry and influencing their foraging behavior.

  19. Influence of some bacterial and host factors on colonization and invasiveness of Escherichia coli K1 in neonatal rats.

    OpenAIRE

    Wullenweber, M; Beutin, L; Zimmermann, S; Jonas, C

    1993-01-01

    Of 209 healthy infants examined, 44 (21.1%) carried Escherichia coli K1 in their feces. Of these 44 isolates, 36 (81.8%) were attributed to 10 different known clonal groups of E. coli K1 and 4 isolates represented unknown types. The influence of mannose-resistant (MR) adhesins, aerobactin production, and resistance to serum on colonization and invasiveness of E. coli K1 in orally infected inbred LEW baby rats was investigated. Strains expressing MR adhesins had significantly higher colonizati...

  20. Quantitative characterization of the influence of the nanoscale morphology of nanostructured surfaces on bacterial adhesion and biofilm formation.

    Directory of Open Access Journals (Sweden)

    Ajay Vikram Singh

    Full Text Available Bacterial infection of implants and prosthetic devices is one of the most common causes of implant failure. The nanostructured surface of biocompatible materials strongly influences the adhesion and proliferation of mammalian cells on solid substrates. The observation of this phenomenon has led to an increased effort to develop new strategies to prevent bacterial adhesion and biofilm formation, primarily through nanoengineering the topology of the materials used in implantable devices. While several studies have demonstrated the influence of nanoscale surface morphology on prokaryotic cell attachment, none have provided a quantitative understanding of this phenomenon. Using supersonic cluster beam deposition, we produced nanostructured titania thin films with controlled and reproducible nanoscale morphology respectively. We characterized the surface morphology; composition and wettability by means of atomic force microscopy, X-ray photoemission spectroscopy and contact angle measurements. We studied how protein adsorption is influenced by the physico-chemical surface parameters. Lastly, we characterized Escherichia coli and Staphylococcus aureus adhesion on nanostructured titania surfaces. Our results show that the increase in surface pore aspect ratio and volume, related to the increase of surface roughness, improves protein adsorption, which in turn downplays bacterial adhesion and biofilm formation. As roughness increases up to about 20 nm, bacterial adhesion and biofilm formation are enhanced; the further increase of roughness causes a significant decrease of bacterial adhesion and inhibits biofilm formation. We interpret the observed trend in bacterial adhesion as the combined effect of passivation and flattening effects induced by morphology-dependent protein adsorption. Our findings demonstrate that bacterial adhesion and biofilm formation on nanostructured titanium oxide surfaces are significantly influenced by nanoscale morphological

  1. Si+ ion implantation reduces the bacterial accumulation on the Ti6Al4V surface

    International Nuclear Information System (INIS)

    Gallardo-Moreno, A M; Pacha-Olivenza, M A; Perera-Nunez, J; Gonzalez-Carrasco, J L; Gonzalez-Martin, M L

    2010-01-01

    Ti6Al4V is one of the most commonly used biomaterials in orthopedic applications due to its interesting mechanical properties and reasonable biocompatibility. Nevertheless, after the implantation, microbial adhesion to its surface can provoke severe health problems associated to the development of biofilms and subsequent infectious processes. This work shows a modification of the Ti6Al4V surface by Si+ ion implantation which reduces the bacterial accumulation under shear forces. Results have shown that the number of bacteria remaining on the surface at the end of the adhesion experiments decreased for silicon-treated surface. In general, the new surface also behaved as less adhesive under in vitro flow conditions. Since no changes are observed in the electrical characteristics between the control and implanted samples, differences are likely related to small changes observed in hydrophobicity.

  2. Seasonal variability in bacterial and fungal diversity of the near-surface atmosphere.

    Science.gov (United States)

    Bowers, Robert M; Clements, Nicholas; Emerson, Joanne B; Wiedinmyer, Christine; Hannigan, Michael P; Fierer, Noah

    2013-01-01

    Bacteria and fungi are ubiquitous throughout the Earth's lower atmosphere where they often represent an important component of atmospheric aerosols with the potential to impact human health and atmospheric dynamics. However, the diversity, composition, and spatiotemporal dynamics of these airborne microbes remain poorly understood. We performed a comprehensive analysis of airborne microbes across two aerosol size fractions at urban and rural sites in the Colorado Front Range over a 14-month period. Coarse (PM10-2.5) and fine (PM2.5) particulate matter samples were collected at weekly intervals with both bacterial and fungal diversity assessed via high-throughput sequencing. The diversity and composition of the airborne communities varied across the sites, between the two size fractions, and over time. Bacteria were the dominant type of bioaerosol in the collected air samples, while fungi and plants (pollen) made up the remainder, with the relative abundances of fungi peaking during the spring and summer months. As bacteria made up the majority of bioaerosol particles, we analyzed the bacterial communities in greater detail using a bacterial-specific 16S rRNA gene sequencing approach. Overall, bacterial taxonomic richness and the relative abundances of specific bacterial taxa exhibited significant patterns of seasonality. Likewise, airborne bacterial communities varied significantly between sites and across aerosol size fractions. Source-tracking analyses indicate that soils and leaves represented important sources of bacteria to the near-surface atmosphere across all locations with cow fecal bacteria also representing an important source of bioaerosols at the more rural sites during early fall and early spring. Together, these data suggest that a complex set of environmental factors, including changes in atmospheric conditions and shifts in the relative importance of available microbial sources, act to control the composition of microbial bioaerosols in rural and

  3. In vitro Candida colonization on acrylic resins and denture liners: influence of surface free energy, roughness, saliva, and adhering bacteria.

    Science.gov (United States)

    Pereira-Cenci, Tatiana; Pereira, Tatiana; Cury, Altair Antoninha Del Bel; Cenci, Maximiliano Sérgio; Rodrigues-Garcia, Renata Cunha Matheus

    2007-01-01

    This study aimed to determine the influence of surface roughness (Ra), surface free energy (SFE), saliva, and bacteria on Candida adhesion to denture materials. The Ra and SFE of 2 acrylic resin specimens and 2 denture liner specimens were measured and assayed in a flow chamber for bacteria culture perfusion plus Candida albicans or C glabrata cultures. Adhesion was determined by counting under light microscopy. Candida adhesion showed significant differences depending on the factors involved. The overall colonization was significantly decreased by saliva and influenced by bacteria. Candida adhesion was strongly affected by Ra, saliva, and bacteria, but not by SFE.

  4. Deadaption and Readaptation with Lactose, But No Cross-Adaptation to Lactulose: A Case of Occult Colonic Bacterial Adaptation

    Directory of Open Access Journals (Sweden)

    Andrew Szilagyi

    2004-01-01

    Full Text Available The standard 3 h breath hydrogen (3hBH2 test distinguishes lactose maldigesters from lactose digesters. However, multiple factors impact on BH2 and care is needed to exclude a priori variables. When these factors are controlled, a negative BH2 test implies lactase persistent status or lactase nonpersistent status with colonic adaptation. A case of a Sicilian man who tested negative (lactase persistent status confirmed on an initial 50 g lactose challenge is described. It was observed that he consumed 28.1 g lactose/day before testing. He subsequently underwent five additional challenge tests in the course of the next 10 months. In four tests the dose intake of lactose was varied upon instruction, and in the fifth test a 30 g lactulose challenge was carried out. It was demonstrated that on radically decreasing lactose intake, a full lactase nonpersistent status was unmasked. Output of 3hBH2 varied inversely with daily lactose intake. Finally, at a time when he was readapted to lactose, there was no discernible adaptation to lactulose challenge. It was concluded that 'occult' colonically adapted subjects may contribute to negative BH2 tests. There is a relationship between variation in lactose intake and the results of BH2 testing. Finally, there was no cross-adaptation to lactulose challenge when lactose was used as the adapting sugar.

  5. Effect of surface topological structure and chemical modification of flame sprayed aluminum coatings on the colonization of Cylindrotheca closterium on their surfaces

    Science.gov (United States)

    Chen, Xiuyong; He, Xiaoyan; Suo, Xinkun; Huang, Jing; Gong, Yongfeng; Liu, Yi; Li, Hua

    2016-12-01

    Biofouling is one of the major problems for the coatings used for protecting marine infrastructures during their long-term services. Regulation in surface structure and local chemistry is usually the key for adjusting antifouling performances of the coatings. In this study, flame sprayed multi-layered aluminum coatings with micropatterned surfaces were constructed and the effects of their surface structure and chemistry on the settlement of typical marine diatoms were investigated. Micropatterned topographical morphology of the coatings was constructed by employing steel mesh as a shielding plate during the coating deposition. A silicone elastomer layer for sealing and interconnection was further brush-coated on the micropatterned coatings. Additional surface modification was made using zwitterionic molecules via DOPA linkage. The surface-modified coatings resist effectively colonization of Cylindrotheca closterium. This is explained by the quantitative examination of a simplified conditioning layer that deteriorated adsorption of bovine calf serum proteins on the zwitterionic molecule-treated samples is revealed. The colonization behaviors of the marine diatoms are markedly influenced by the micropatterned topographical morphology. Either the surface micropatterning or the surface modification by zwitterionic molecules enhances antimicrobial ability of the coatings. However, the combined micropatterned structure and zwitterionic modification do not show synergistic effect. The results give insight into anti-corrosion/fouling applications of the modified aluminum coatings in the marine environment.

  6. Effect of temperature and colonization of Legionella pneumophila and Vermamoeba vermiformis on bacterial community composition of copper drinking water biofilms

    OpenAIRE

    Buse, Helen Y.; Ji, Pan; Gomez?Alvarez, Vicente; Pruden, Amy; Edwards, Marc A.; Ashbolt, Nicholas J.

    2017-01-01

    Summary It is unclear how the water?based pathogen, Legionella pneumophila (Lp), and associated free?living amoeba (FLA) hosts change or are changed by the microbial composition of drinking water (DW) biofilm communities. Thus, this study characterized the bacterial community structure over a 7?month period within mature (>?600?day?old) copper DW biofilms in reactors simulating premise plumbing and assessed the impact of temperature and introduction of Lp and its FLA host, Vermamoeba vermifor...

  7. Changes in bacterial community structure in the colon of pigs fed different experimental diets and after infection with Brachyspira hyodysenteriae

    DEFF Research Database (Denmark)

    Leser, Thomas D.; Lindecrona, Rikke Hvid; Jensen, Tim Kåre

    2000-01-01

    Bacterial communities in the large intestines of pigs were compared using terminal restriction fragment length polymorphism (T-RFLP) analysis targeting the 16S ribosomal DNA. The pigs were fed different experimental diets based on either modified standard feed or cooked rice supplemented with die...... between two independent but identical experiments. When the animals were experimentally infected with Brachyspira hyodysenteriae, causing swine dysentery, many of the T-RFs fluctuated, suggesting a destabilization of the microbial community....

  8. Covalent Immobilization of Enoxacin onto Titanium Implant Surfaces for Inhibiting Multiple Bacterial Species Infection and In Vivo Methicillin-Resistant Staphylococcus aureus Infection Prophylaxis.

    Science.gov (United States)

    Nie, Bin'en; Long, Teng; Ao, Haiyong; Zhou, Jianliang; Tang, Tingting; Yue, Bing

    2017-01-01

    Infection is one of the most important causes of titanium implant failure in vivo A developing prophylactic method involves the immobilization of antibiotics, especially vancomycin, onto the surface of the titanium implant. However, these methods have a limited effect in curbing multiple bacterial infections due to antibiotic specificity. In the current study, enoxacin was covalently bound to an amine-functionalized Ti surface by use of a polyethylene glycol (PEG) spacer, and the bactericidal effectiveness was investigated in vitro and in vivo The titanium surface was amine functionalized with 3-aminopropyltriethoxysilane (APTES), through which PEG spacer molecules were covalently immobilized onto the titanium, and then the enoxacin was covalently bound to the PEG, which was confirmed by X-ray photoelectron spectrometry (XPS). A spread plate assay, confocal laser scanning microscopy (CLSM), and scanning electron microscopy (SEM) were used to characterize the antimicrobial activity. For the in vivo study, Ti implants were inoculated with methicillin-resistant Staphylococcus aureus (MRSA) and implanted into the femoral medullary cavity of rats. The degree of infection was assessed by radiography, micro-computed tomography, and determination of the counts of adherent bacteria 3 weeks after surgery. Our data demonstrate that the enoxacin-modified PEGylated Ti surface effectively prevented bacterial colonization without compromising cell viability, adhesion, or proliferation in vitro Furthermore, it prevented MRSA infection of the Ti implants in vivo Taken together, our results demonstrate that the use of enoxacin-modified Ti is a potential approach to the alleviation of infections of Ti implants by multiple bacterial species. Copyright © 2016 American Society for Microbiology.

  9. Bacterial colonization of the implant-abutment interface of conical connection with an internal octagon: an in vitro study using real-time PCR.

    Science.gov (United States)

    Baj, A; Beltramini, G A; Bolzoni, A; Cura, F; Palmieri, A; Scarano, A; Ottria, L; Giannì, A B

    2017-01-01

    Bacterial leakage at the implant-abutment connection of a two-piece implant system is considered the main cause of peri-implantitis. Prevention of bacterial leakage at the implant-abutment connection is mandatory for reducing inflammation process around implant neck and achieving bone stability. Micro-cavities at implant-abutment connection level can favour bacterial leakage, even in modern two-piece implant systems. The conical connection with an internal octagon (CCIO) is considered to be more stable mechanically and allows a more tight link between implant and abutment. As P. gingivalis and T. forsythia penetration might have clinical relevance, it was the purpose of this investigation to evaluate molecular leakage of these two bacteria in a new two-implant system with an internal conical implant-abutment connection with internal octagon (Shiner XT, FMD Falappa Medical Devices S.p.A. Rome, Italy). To verify the ability of the implant in protecting the internal space from the external environment, the passage of genetically modified Escherichia c oli across implant-abutment interface was evaluated. Four Shiner XT implants (FMD, Falappa Medical Devices®, Rome, Italy) were immerged in a bacterial culture for 24 h and bacteria amount was measured inside implant-abutment interface with Real-time PCR. Bacteria were detected inside all studied implants, with a median percentage of 6% for P. gingivalis and 5% for T. forsythia. Other comparable studies about the tightness of the tested implant system reported similar results. The gap size at the implant-abutment connection of CCIOs was measured by other authors discovering a gap size of 1–2μm of the AstraTech system and of 4μm for the Ankylos system. Bacterial leakage along implant-abutment connection of cylindrical and tapered implants, Shiner XT, (FMD Falappa Medical Devices S.p.A. Rome, Italy) showed better results compared to other implants. Additional studies are needed to explore the relationship in terms of

  10. Influence of biological fluids in bacterial viability on different hospital surfaces and fomites.

    Science.gov (United States)

    Esteves, Deigilam C; Pereira, Valeria C; Souza, Joyce M; Keller, Rogéria; Simões, Rebeca D; Winkelstroter Eller, Lizziane K; Rodrigues, Marcus Vinicius P

    2016-03-01

    The hospital environment is susceptible to bacterial contamination along with survival in fomites and surfaces, allowing dissemination of potential pathogenic strains. The present research aimed to evaluate the influence of biological fluids in bacterial viability on fomites and surfaces commonly present in nosocomial environment. Four different fomites and surfaces (ceramic floor, cotton fabric fragments and synthetic fibers, and eggcrate foam mattress) were contaminated with potential pathogens (Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa, and Klebsiella pneumoniae), then submitted to influence of biological fluids (blood, urine, artificial saliva). The viability of strains was evaluated at 24 hours after contamination and then in intervals of 7 days, by the colony-forming unit count technique. S aureus presented viability (>70 days) in all conditions tested, E faecalis and K pneumoniae had decreased viability over time, and E coli did not exhibit a growth relationship with surfaces or fluids. Persistence and adaptability capacity of potential pathogens in fomites and surfaces exposed to the patient are important for guidance, planning, and outlining of protocols for microorganism dissemination control and prevention in the health care environment. Copyright © 2016 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  11. Identification of Bacterial Surface Antigens by Screening Peptide Phage Libraries Using Whole Bacteria Cell-Purified Antisera

    Science.gov (United States)

    Hu, Yun-Fei; Zhao, Dun; Yu, Xing-Long; Hu, Yu-Li; Li, Run-Cheng; Ge, Meng; Xu, Tian-Qi; Liu, Xiao-Bo; Liao, Hua-Yuan

    2017-01-01

    Bacterial surface proteins can be good vaccine candidates. In the present study, we used polyclonal antibodies purified with intact Erysipelothrix rhusiopthiae to screen phage-displayed random dodecapeptide and loop-constrained heptapeptide libraries, which led to the identification of mimotopes. Homology search of the mimotope sequences against E. rhusiopthiae-encoded ORF sequences revealed 14 new antigens that may localize on the surface of E. rhusiopthiae. When these putative surface proteins were used to immunize mice, 9/11 antigens induced protective immunity. Thus, we have demonstrated that a combination of using the whole bacterial cells to purify antibodies and using the phage-displayed peptide libraries to determine the antigen specificities of the antibodies can lead to the discovery of novel bacterial surface antigens. This can be a general approach for identifying surface antigens for other bacterial species. PMID:28184219

  12. Intestinal Colonization Dynamics of Vibrio cholerae

    Science.gov (United States)

    Almagro-Moreno, Salvador; Pruss, Kali; Taylor, Ronald K.

    2015-01-01

    To cause the diarrheal disease cholera, Vibrio cholerae must effectively colonize the small intestine. In order to do so, the bacterium needs to successfully travel through the stomach and withstand the presence of agents such as bile and antimicrobial peptides in the intestinal lumen and mucus. The bacterial cells penetrate the viscous mucus layer covering the epithelium and attach and proliferate on its surface. In this review, we discuss recent developments and known aspects of the early stages of V. cholerae intestinal colonization and highlight areas that remain to be fully understood. We propose mechanisms and postulate a model that covers some of the steps that are required in order for the bacterium to efficiently colonize the human host. A deeper understanding of the colonization dynamics of V. cholerae and other intestinal pathogens will provide us with a variety of novel targets and strategies to avoid the diseases caused by these organisms. PMID:25996593

  13. Multiplex flow cytometry barcoding and antibody arrays identify surface antigen profiles of primary and metastatic colon cancer cell lines.

    Directory of Open Access Journals (Sweden)

    Kumar Sukhdeo

    Full Text Available Colon cancer is a deadly disease affecting millions of people worldwide. Current treatment challenges include management of disease burden as well as improvements in detection and targeting of tumor cells. To identify disease state-specific surface antigen signatures, we combined fluorescent cell barcoding with high-throughput flow cytometric profiling of primary and metastatic colon cancer lines (SW480, SW620, and HCT116. Our multiplexed technique offers improvements over conventional methods by permitting the simultaneous and rapid screening of cancer cells with reduced effort and cost. The method uses a protein-level analysis with commercially available antibodies on live cells with intact epitopes to detect potential tumor-specific targets that can be further investigated for their clinical utility. Multiplexed antibody arrays can easily be applied to other tumor types or pathologies for discovery-based approaches to target identification.

  14. Influence of surface-energy components of Ni-P-TiO2-PTFE nanocomposite coatings on bacterial adhesion.

    Science.gov (United States)

    Liu, Chen; Zhao, Qi

    2011-08-02

    The influence of total surface energy on bacterial adhesion has been investigated intensively with the frequent conclusion that bacterial adhesion is less on low-energy surfaces. However, there are also a number of contrary findings that high-energy surfaces have a smaller biofouling tendency. Recently, it was found that the CQ ratio, which is defined as the ratio of Lifshitz-van der Waals (LW) apolar to electron donor surface-energy components of substrates, has a strong correlation to bacterial adhesion. However, the electron donor surface-energy components of substrates varied over only a very limited range. In this article, a series of Ni-P-TiO(2)-PTFE nanocomposite coatings with wide range of surface-energy components were prepared using an electroless plating technique. The bacterial adhesion and removal on the coatings were evaluated with different bacteria under both static and flow conditions. The experimental results demonstrated that there was a strong correlation between bacterial attachment (or removal) and the CQ ratio. The coatings with the lowest CQ ratio had the lowest bacterial adhesion or the highest bacterial removal, which was explained using the extented DLVO theory.

  15. Chemical mediation of bacterial surface colonisation by secondary metabolites from the red alga Delisea pulchra

    DEFF Research Database (Denmark)

    Maximilien, Ria; de Nys, Rocky; Holmström, Carola

    1998-01-01

    experimentally investigated inhibition of marine bacteria by furanones, initially testing the effects of crude extract of D. pulchra (about 50 % of which is furanones) on the growth of 144 strains of bacteria isolated from the surfaces of D. pulchra, nearby rocks, or a co-occurring alga (Sasgassum vestitum......We investigated the effects of halogenated furanones from the red alga Delisea pulchra on colonisation of surfaces by marine bacteria. Bacterial abundance on the surface of D. pulchra, assessed using scanning electron microscopy (SEM), was significantly lower than on the surfaces of 3 co......). This crude extract did not strongly inhibit growth of these bacteria; 79% of the strains grew at 50 pg ml(-1) of crude extract, and 63 % grew at 500 mu g ml(-1). Inhibition of growth that did occur was strongly source dependent, with bacteria isolated from rocks the least affected, and strains from D...

  16. Surface colonized silver nano particles over chitosan poly-electrolyte micro-spheres and their multi-functional behavior

    Science.gov (United States)

    Prakash, B.; Asha, S.; Nimrodh Ananth, A.; Vanithakumari, G.; Okram, G. S.; Jose, Sujin P.; Jothi Rajan, M. A.

    2018-02-01

    Chitosan/tripolyphosphate polyelectrolyte (TPP) microspheres, decorated and surface functionalized with silver nanoparticles (NPs) of average diameter of 15 nm, were synthesized following a simple two-step procedure. These Ag NP-functionalized polyelectrolyte microspheres (Ag-CSPMs) are found to be biocompatible and enhancing the reactive oxygen species in curcumin with excellent anti-bacterial activity for selected Gram-positive and negative bacterial strains, making them much attractive relative to bare surface counterparts; the well-stabilized silver NPs do not form any agglomerations on the surface of the chitosan microspheres. They also show excellent cytotoxic behavior towards MCF7 cell lines, showing a half-maximal inhibitory concentration (IC50) of 32 μg ml-1. Therefore, Ag-CSPMs exhibit multi-functional ability having potential towards theranostics applications.

  17. Evaluation of penicylinders used in disinfectant testing: bacterial attachment and surface texture.

    Science.gov (United States)

    Cole, E C; Rutala, W A; Carson, J L

    1987-01-01

    Two possible deficiencies in the AOAC use-dilution method for registration of chemical disinfectants by the Environmental Protection Agency are examined: (1) the physical disparities among brands of penicylinders and (2) the variability of bacterial numbers on penicylinders depending upon test strain and penicylinder surface texture. Textural differences of 2 brands of stainless steel penicylinders, one brand of porcelain, and one brand of glass were assessed by scanning electron microscopy. A considerable variation in smoothness of both inner and outer surfaces of stainless steel and porcelain penicylinders was observed. Glass penicylinders were very smooth. Numbers of bacteria attached to a penicylinder were assessed by vortexing the penicylinders 30 s at No. 4 after using the AOAC method of bacterial inoculation and drying 40 min at 37 degrees C. With this methodology, stainless steel carriers retained the 3 AOAC-recommended bacterial test strains differentially: ca 10(7) for Pseudomonas aeruginosa, 5 X 10(6) for Staphylococcus aureus, and 10(6) for Salmonella choleraesuis; glass retained 10(6)-10(7) organisms of all 3 test strains; porcelain retained about that amount of S. aureus but 10(5)-10(6) P. aeruginosa and 10(3)-10(4) S. choleraesuis. These data suggest that disinfectants are not similarly challenged with the AOAC-recommended test bacteria and that an alternative method should be considered to ensure comparable numbers of bacteria on penicylinders.

  18. The effect of iatrogenic Staphylococcus epidermidis intercellar adhesion operon on the formation of bacterial biofilm on polyvinyl chloride surfaces.

    Science.gov (United States)

    Lianhua, Ye; Yunchao, Huang; Guangqiang, Zhao; Kun, Yang; Xing, Liu; Fengli, Guo

    2014-12-01

    The intercellular adhesion gene (ica) of Staphylococcus epidermidis is a key factor for bacterial aggregation. This study explored the effect of ica on the formation of bacterial biofilm on polyvinyl chloride (PVC) surfaces. Genes related to bacterial biofilm formation, including 16S rRNA, autolysin (atlE), fibrinogen binding protein gene (fbe), and ica were identified and sequenced from 112 clinical isolates of iatrogenic S. epidermidis by polymerase chain reaction (PCR) and gene sequencing. Based on the sequencing result, ica operon-positive (icaADB+/atlE+/fbe+) and ica operon-negative (icaADB-/atlE+/fbe+) strains were separated and co-cultivated with PVC material. After 6, 12, 18, 24, and 30 h of co-culture, the thickness of the bacterial biofilm and quantity of bacterial colony on the PVC surface were measured under the confocal laser scanning microscope and scanning electron microscope. The positive rate of S. epidermidis-specific 16SrRNA in 112 iatrogenic strains was 100% (112/112). The genotype of ica-positive (icaADB+/atlE+/fbe+) strains accounted for 57.1% (64/112), and genotype of ica-negative (icaADB-/atlE+/fbe+) strains accounted for 37.5% (42/112). During 30 h of co-culture, no obvious bacterial biofilm formed on the surface of PVC in the ica-positive group, however, mature bacterial biofilm structure formed after 24 h. For all time points, thickness of bacterial biofilm and quantity of bacterial colony on PVC surfaces in the ica operon-positive group were significantly higher than those in ica operon-negative group (poperon-negative and ica operon-positive strains. The ica operon plays an important role in bacterial biofilm formation and bacterial multiplication on PVC material.

  19. Modeling bacterial attachment to surfaces as an early stage of biofilm development.

    Science.gov (United States)

    El Moustaid, Fadoua; Eladdadi, Amina; Uys, Lafras

    2013-06-01

    Biofilms are present in all natural, medical and industrial surroundings where bacteria live. Biofilm formation is a key factor in the growth and transport of both beneficial and harmful bacteria. While much is known about the later stages of biofilm formation, less is known about its initiation which is an important first step in the biofilm formation. In this paper, we develop a non-linear system of partial differential equations of Keller-Segel type model in one-dimensional space, which couples the dynamics of bacterial movement to that of the sensing molecules. In this case, bacteria perform a biased random walk towards the sensing molecules. We derive the boundary conditions of the adhesion of bacteria to a surface using zero-Dirichlet boundary conditions, while the equation describing sensing molecules at the interface needed particular conditions to be set. The numerical results show the profile of bacteria within the space and the time evolution of the density within the free-space and on the surface. Testing different parameter values indicate that significant amount of sensing molecules present on the surface leads to a faster bacterial movement toward the surface which is the first step of biofilm initiation. Our work gives rise to results that agree with the biological description of the early stages of biofilm formation.

  20. Bacterial adhesion to protein-coated surfaces: An AFM and QCM-D study

    Science.gov (United States)

    Strauss, Joshua; Liu, Yatao; Camesano, Terri A.

    2009-09-01

    Bacterial adhesion to biomaterials, mineral surfaces, or other industrial surfaces is strongly controlled by the way bacteria interact with protein layers or organic matter and other biomolecules that coat the materials. Despite this knowledge, many studies of bacterial adhesion are performed under clean conditions, instead of in the presence of proteins or organic molecules. We chose fetal bovine serum (FBS) as a model protein, and prepared FBS films on quartz crystals. The thickness of the FBS layer was characterized using atomic force microscopy (AFM) imaging under liquid and quartz crystal microbalance with dissipation (QCM-D). Next, we characterized how the model biomaterial surface would interact with the nocosomial pathogen Staphylococcus epidermidis. An AFM probe was coated with S. epidermidis cells and used to probe a gold slide that had been coated with FBS or another protein, fibronectin (FN). These experiments show that AFM and QCM-D can be used in complementary ways to study the complex interactions between bacteria, proteins, and surfaces.

  1. Cooperative Binding and Activation of Fibronectin by a Bacterial Surface Protein*

    Science.gov (United States)

    Marjenberg, Zoe R.; Ellis, Ian R.; Hagan, Robert M.; Prabhakaran, Sabitha; Höök, Magnus; Talay, Susanne R.; Potts, Jennifer R.; Staunton, David; Schwarz-Linek, Ulrich

    2011-01-01

    Integrin-dependent cell invasion of some pathogenic bacteria is mediated by surface proteins targeting the extracellular matrix protein fibronectin (FN). Although the structural basis for bacterial FN recognition is well understood, it has been unclear why proteins such as streptococcal SfbI contain several FN-binding sites. We used microcalorimetry to reveal cooperative binding of FN fragments to arrays of binding sites in SfbI. In combination with thermodynamic analyses, functional cell-based assays show that SfbI induces conformational changes in the N-terminal 100-kDa region of FN (FN100kDa), most likely by competition with intramolecular interactions defining an inactive state of FN100kDa. This study provides insights into how long range conformational changes resulting in FN activation may be triggered by bacterial pathogens. PMID:21059652

  2. Plasma of Argon Increases Cell Attachment and Bacterial Decontamination on Different Implant Surfaces.

    Science.gov (United States)

    Canullo, Luigi; Genova, Tullio; Wang, Hom-Lay; Carossa, Stefano; Mussano, Federico

    This in vitro study tested the effects of argon atmospheric pressure dielectric barrier discharge (APDBD) on different implant surfaces with regard to physical changes, bacterial decontamination, and osteoblast adhesion. Seven hundred twenty disks with three different surface topographies-machined (MAC), titanium plasma-sprayed (TPS), and zirconia-blasted and acid-etched (ZRT)-were tested in this experiment. Bacterial adhesion tests were performed repeatedly on a simplified biofilm of Streptococcus mitis. Bacteria were incubated in the presence of the samples, which were subsequently either left untreated as controls or treated with APDBD for 30, 60, and 120 seconds. Samples were then metalized, prior to the recurring acquisition of images using a scanning electronic microscope (SEM). Protein adsorption, surface wettability, and early biologic response were determined for both treated (120 seconds) and untreated implant surfaces. For depicting the eukaryotic cell behavior, preosteoblastic murine cells were used. Cells were conveniently stained, and nuclei were counted. Cell viability was assessed by a chemiluminescent assay at 1, 2, and 3 days. On all treated samples, values of the contact angle measurements were lower than 10 degrees. The untreated samples showed values of contact angle of 80, 100, and 110 degrees, respectively, for MAC, TPS, and ZRT. The protein adsorption on TPS and ZRT was significantly increased after the plasma of argon treatment. However, no significant effect was noted on the MAC disks. The number and the cell spreading area of adherent osteoblasts significantly increased in all treated surfaces. Nonetheless, argon treatment did not influence the osteoblast proliferation and viability at different time points. Bacteria adhesion was significantly reduced, even after 60 seconds of argon treatment. Preliminary data showed that argon atmospheric pressure dielectric barrier discharge disinfected the implant surface, with potential to promote

  3. Bacterial cell surface properties: role of loosely bound extracellular polymeric substances (LB-EPS).

    Science.gov (United States)

    Zhao, Wenqiang; Yang, Shanshan; Huang, Qiaoyun; Cai, Peng

    2015-04-01

    This study investigated the effect of loosely bound extracellular polymeric substances (LB-EPS) on the comprehensive surface properties of four bacteria (Bacillus subtilis, Streptococcus suis, Escherichia coli and Pseudomonas putida). The removal of LB-EPS from bacterial surfaces by high-speed centrifugation (12,000×g) was confirmed by SEM images. Viability tests showed that the percentages of viable cells ranged from 95.9% to 98.0%, and no significant difference was found after treatment (P>0.05). FTIR spectra revealed the presence of phosphodiester, carboxylic, phosphate, and amino functional groups on bacteria surfaces, and the removal of LB-EPS did not alter the types of cell surface functional groups. Potentiometric titration results suggested the total site concentrations on the intact bacteria were higher than those on LB-EPS free bacteria. Most of the acidity constants (pKa) were almost identical, except the increased pKa values of phosphodiester groups on LB-EPS free S. suis and E. coli surfaces. The electrophoretic mobilities and hydrodynamic diameters of the intact and LB-EPS free bacteria were statistically unchanged (P>0.05), indicating LB-EPS had no influence on the net surface charges and size distribution of bacteria. However, LB-ESP could enhance cell aggregation processes. The four LB-EPS free bacteria all exhibited fewer hydrophobicity values (26.1-65.0%) as compared to the intact cells (47.4-69.3%), suggesting the removal of uncharged nonpolar compounds (e.g., carbohydrates) in LB-EPS. These findings improve our understanding of the changes in cell surface characterizations induced by LB-EPS, and have important implications for assessing the role of LB-EPS in bacterial adhesion and transport behaviors. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Surface layers of Xanthomonas malvacearum, the cause of bacterial blight of cotton.

    Science.gov (United States)

    Verma, J P; Formanek, H

    1981-01-01

    Mureins were isolated from two strains of Xanthomonas malvacearum, a phytopathogenic bacterium causing bacterial blight of cotton. The purity of murein was 70-95 % and the amino acid and amino sugar components (glutamic acid, alanina, meso-disminopimelic acid, muramic acid and glucosamine) were present at the molar ratio of 1:1.9:1:l.12.0.85. The bacterium secreted a copious amount of slime which masked itd surface structure. The slime was composed of densley interwoven network of filamentous material originating from the cell surface and extended into the medium without and discernable boundary. The slime was secreted through surface layers pores by force, giving the effect of a spray or jet. Slime also played a role in chain formatin of baterial cells.

  5. Surface contact stimulates the just-in-time deployment of bacterial adhesins.

    Science.gov (United States)

    Li, Guanglai; Brown, Pamela J B; Tang, Jay X; Xu, Jing; Quardokus, Ellen M; Fuqua, Clay; Brun, Yves V

    2012-01-01

    The attachment of bacteria to surfaces provides advantages such as increasing nutrient access and resistance to environmental stress. Attachment begins with a reversible phase, often mediated by surface structures such as flagella and pili, followed by a transition to irreversible attachment, typically mediated by polysaccharides. Here we show that the interplay between pili and flagellum rotation stimulates the rapid transition between reversible and polysaccharide-mediated irreversible attachment. We found that reversible attachment of Caulobacter crescentus cells is mediated by motile cells bearing pili and that their contact with a surface results in the rapid pili-dependent arrest of flagellum rotation and concurrent stimulation of polar holdfast adhesive polysaccharide. Similar stimulation of polar adhesin production by surface contact occurs in Asticcacaulis biprosthecum and Agrobacterium tumefaciens. Therefore, single bacterial cells respond to their initial contact with surfaces by triggering just-in-time adhesin production. This mechanism restricts stable attachment to intimate surface interactions, thereby maximizing surface attachment, discouraging non-productive self-adherence, and preventing curing of the adhesive. © 2011 Blackwell Publishing Ltd.

  6. Surface structures involved in plant stomata and leaf colonization by Shiga-toxigenic Escherichia coli O157:H7

    Directory of Open Access Journals (Sweden)

    Zeus eSaldaña

    2011-05-01

    Full Text Available Shiga-toxigenic Escherichia coli (STEC O157:H7 uses a myriad of surface adhesive appendages including pili, flagella, and the type 3 secretion system (T3SS to adhere to and inflict damage to the human gut mucosa. Consumption of contaminated ground beef, milk, juices, water or leafy greens has been associated with outbreaks of diarrheal disease in humans due to STEC. The aim of this study was to investigate which of the known STEC O157:H7 adherence factors mediate colonization of baby spinach leaves and where the bacteria reside within tainted leaves. We found that STEC O157:H7 colonizes baby spinach leaves through the coordinated production of curli, the E. coli common pilus (ECP, hemorrhagic coli type 4 pilus (HCP, flagella, and T3SS. Electron microscopy analysis of tainted leaves revealed STEC bacteria in the internal cavity of the stomata, in intercellular spaces, and within vascular tissue (xylem and phloem, where the bacteria were protected from the bactericidal effect of gentamicin, sodium hypochlorite or ozonated water treatments. We confirmed that the T3S escN mutant showed a reduced number of bacteria within the stomata suggesting that T3S is required for the successful colonization of leaves. In agreement, non-pathogenic E. coli K-12 strain DH5α transformed with a plasmid carrying the LEE pathogenicity island, harboring the T3SS and effector genes, internalized into stomata more efficiently than without the LEE. This study highlights a role for pili, flagella, and T3SS in the interaction of STEC with spinach leaves. Colonization of plant stomata and internal tissues may constitute a strategy by which STEC survives in a nutrient-rich microenvironment protected from external foes and may be a potential source for human infection.

  7. Surface structures involved in plant stomata and leaf colonization by shiga-toxigenic Escherichia coli o157:h7.

    Science.gov (United States)

    Saldaña, Zeus; Sánchez, Ethel; Xicohtencatl-Cortes, Juan; Puente, Jose Luis; Girón, Jorge A

    2011-01-01

    Shiga-toxigenic Escherichia coli (STEC) O157:H7 uses a myriad of surface adhesive appendages including pili, flagella, and the type 3 secretion system (T3SS) to adhere to and inflict damage to the human gut mucosa. Consumption of contaminated ground beef, milk, juices, water, or leafy greens has been associated with outbreaks of diarrheal disease in humans due to STEC. The aim of this study was to investigate which of the known STEC O157:H7 adherence factors mediate colonization of baby spinach leaves and where the bacteria reside within tainted leaves. We found that STEC O157:H7 colonizes baby spinach leaves through the coordinated production of curli, the E. coli common pilus, hemorrhagic coli type 4 pilus, flagella, and T3SS. Electron microscopy analysis of tainted leaves revealed STEC bacteria in the internal cavity of the stomata, in intercellular spaces, and within vascular tissue (xylem and phloem), where the bacteria were protected from the bactericidal effect of gentamicin, sodium hypochlorite or ozonated water treatments. We confirmed that the T3S escN mutant showed a reduced number of bacteria within the stomata suggesting that T3S is required for the successful colonization of leaves. In agreement, non-pathogenic E. coli K-12 strain DH5α transformed with a plasmid carrying the locus of enterocyte effacement (LEE) pathogenicity island, harboring the T3SS and effector genes, internalized into stomata more efficiently than without the LEE. This study highlights a role for pili, flagella, and T3SS in the interaction of STEC with spinach leaves. Colonization of plant stomata and internal tissues may constitute a strategy by which STEC survives in a nutrient-rich microenvironment protected from external foes and may be a potential source for human infection.

  8. Investigation of Clinical Relevance of Bacterial Colonization in Patients With Suspected Viral Respiratory Tract Infection By Using Multiplex PCR Method

    Directory of Open Access Journals (Sweden)

    Vedat Turhan

    2013-02-01

    Full Text Available Numerous viral and bacterial pathogens have been reported causing acute respiratory tract infection (ARTI. Nasopharyngeal swab (NPS specimens from 351 patients (278 children, 73 adults with suspected upper and lower ARTI were submitted during the study period from Jan. 2005 to Dec. 2006. Organism-specific nucleic acids were detected using TemPlex technology (ResPlex I and II, Genaco Biomedical Products, Huntsville, AL. Amplified products were identified using a suspension array for multiplex detection performed on a Luminex 100 instrument (Luminex, Austin, TX. A total of 221 viral and bacterial respiratory agents were detected in 148 patients (135 [48.5%] of the 278 children and 13 [17.8%] of the 73 adults with suspected ARTI. A single respiratory pathogen was detected in 89 patients [25.35%], whereas mixed infection with two or three pathogens was found in 59 [16.8%] of 351 suspected patients. S. pneumonia was the most frequently isolated strain (54 [15.3%] of 351 patients, followed by H. influenzae (37 [10.5%], rhinoviruses (35 [9.9%], influenza A virus (23 [6.5%], enteroviruses (19 [5.4%], hMPV (14 [3.9%], PIV-1 (12 [3.4%], PIV-3 (11 [3.1%], RSV (10 [2.8%], and influenza B virus (6 [1.7%]. Mixed infections were more frequent in children (56 [20.1%] of 278 than adult patients (3 [4.1%] of 73 patients. The detection rate of the bacteria peaked in the spring season (37 [40.6%] of 91 bacteria, followed by winter (24 infections, autumn (18 infections and summer (12 infections. The prevalence of co-infection is ~40%, finding a much higher incidence of co-infection with more than one agent than that reported previously. [Dis Mol Med 2013; 1(1.000: 2-7

  9. Surface activation of graphene oxide nanosheets by ultraviolet irradiation for highly efficient anti-bacterials

    Science.gov (United States)

    Veerapandian, Murugan; Zhang, Linghe; Krishnamoorthy, Karthikeyan; Yun, Kyusik

    2013-10-01

    A comprehensive investigation of anti-bacterial properties of graphene oxide (GO) and ultraviolet (UV) irradiated GO nanosheets was carried out. Microscopic characterization revealed that the GO nanosheet-like structures had wavy features and wrinkles or thin grooves. Fundamental surface chemical states of GO nanosheets (before and after UV irradiation) were investigated using x-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy. Minimum inhibitory concentration (MIC) results revealed that UV irradiated GO nanosheets have more pronounced anti-bacterial behavior than GO nanosheets and standard antibiotic, kanamycin. The MIC of UV irradiated GO nanosheets was 0.125 μg ml-1 for Escherichia coli and Salmonella typhimurium, 0.25 μg ml-1 for Bacillus subtilis and 0.5 μg ml-1 for Enterococcus faecalis, ensuring its potential as an anti-infective agent for controlling the growth of pathogenic bacteria. The minimum bactericidal concentration of normal GO nanosheets was determined to be two-fold higher than its corresponding MIC value, indicating promising bactericidal activity. The mechanism of anti-bacterial action was evaluated by measuring the enzymatic activity of β-d-galactosidase for the hydrolysis of o-nitrophenol-β-d-galactopyranoside.

  10. Surface activation of graphene oxide nanosheets by ultraviolet irradiation for highly efficient anti-bacterials

    International Nuclear Information System (INIS)

    Veerapandian, Murugan; Zhang, Linghe; Yun, Kyusik; Krishnamoorthy, Karthikeyan

    2013-01-01

    A comprehensive investigation of anti-bacterial properties of graphene oxide (GO) and ultraviolet (UV) irradiated GO nanosheets was carried out. Microscopic characterization revealed that the GO nanosheet-like structures had wavy features and wrinkles or thin grooves. Fundamental surface chemical states of GO nanosheets (before and after UV irradiation) were investigated using x-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy. Minimum inhibitory concentration (MIC) results revealed that UV irradiated GO nanosheets have more pronounced anti-bacterial behavior than GO nanosheets and standard antibiotic, kanamycin. The MIC of UV irradiated GO nanosheets was 0.125 μg ml −1 for Escherichia coli and Salmonella typhimurium, 0.25 μg ml −1 for Bacillus subtilis and 0.5 μg ml −1 for Enterococcus faecalis, ensuring its potential as an anti-infective agent for controlling the growth of pathogenic bacteria. The minimum bactericidal concentration of normal GO nanosheets was determined to be two-fold higher than its corresponding MIC value, indicating promising bactericidal activity. The mechanism of anti-bacterial action was evaluated by measuring the enzymatic activity of β-d-galactosidase for the hydrolysis of o-nitrophenol-β-d-galactopyranoside. (paper)

  11. Ecosystem productivity is associated with bacterial phylogenetic distance in surface marine waters.

    Science.gov (United States)

    Galand, Pierre E; Salter, Ian; Kalenitchenko, Dimitri

    2015-12-01

    Understanding the link between community diversity and ecosystem function is a fundamental aspect of ecology. Systematic losses in biodiversity are widely acknowledged but the impact this may exert on ecosystem functioning remains ambiguous. There is growing evidence of a positive relationship between species richness and ecosystem productivity for terrestrial macro-organisms, but similar links for marine micro-organisms, which help drive global climate, are unclear. Community manipulation experiments show both positive and negative relationships for microbes. These previous studies rely, however, on artificial communities and any links between the full diversity of active bacterial communities in the environment, their phylogenetic relatedness and ecosystem function remain hitherto unexplored. Here, we test the hypothesis that productivity is associated with diversity in the metabolically active fraction of microbial communities. We show in natural assemblages of active bacteria that communities containing more distantly related members were associated with higher bacterial production. The positive phylogenetic diversity-productivity relationship was independent of community diversity calculated as the Shannon index. From our long-term (7-year) survey of surface marine bacterial communities, we also found that similarly, productive communities had greater phylogenetic similarity to each other, further suggesting that the traits of active bacteria are an important predictor of ecosystem productivity. Our findings demonstrate that the evolutionary history of the active fraction of a microbial community is critical for understanding their role in ecosystem functioning. © 2015 John Wiley & Sons Ltd.

  12. Characterization of the bacterial community associated with the surface and mucus layer of whiting (Merlangius merlangus).

    Science.gov (United States)

    Smith, Cindy J; Danilowicz, Bret S; Meijer, Wim G

    2007-10-01

    The bacterial community inhabiting the mucus layer and surface of whiting was examined to determine whether the bacteria present are a reflection of the surrounding water or an indigenous bacterial flora is present. The outer mucus, mouth mucus and gut of four whiting harvested from a site in the Irish Sea and the surrounding water were examined by terminal restriction fragment length polymorphism (tRFLP) analysis of the 16S rRNA gene and clone library construction. The water community was the most diverse, with only a small number of shared water-mucus phylotypes present. The bacterial flora associated with the outer mucus layer were more diverse than that of the mouth mucus and gut. All three mucus layers were characterized by the presence of a dominant phylotype, identified as clone wom-1, highly similar to Photobacterium iliopiscarium. In addition to other Photobacterium phylotypes, members of the CFB and Clostridia groups were also detected. Subsequently, whiting from 11 different sites along the east and south coast of Ireland were compared by tRFLP analysis. Strikingly, the mucus layer of whiting at all sites was characterized by the presence and dominance of a TRF corresponding to the clone wom-1 which was virtually absent from the water column.

  13. Interactions between multiple filaments and bacterial biofilms on the surface of an apple

    Science.gov (United States)

    He, CHENG; Maoyuan, XU; Shuhui, PAN; Xinpei, LU; Dawei, LIU

    2018-04-01

    In this paper, the interactions between two dielectric barrier discharge (DBD) filaments and three bacterial biofilms are simulated. The modeling of a DBD streamer is studied by means of 2D finite element calculation. The model is described by the proper governing equations of air DBD at atmospheric pressure and room temperature. The electric field in the computing domain and the self-consistent transportation of reactive species between a cathode and biofilms on the surface of an apple are realized by solving a Poisson equation and continuity equations. The electron temperature is solved by the electron energy conservation equation. The conductivity and permittivity of bacterial biofilms are considered, and the shapes of the bacterial biofilms are irregular in the uncertainty and randomness of colony growth. The distribution of the electrons suggests that two plasma channels divide into three plasma channels when the streamer are 1 mm from the biofilms. The toe-shapes of the biofilms and the simultaneous effect of two streamer heads result in a high electric field around the biofilms, therefore the stronger ionization facilitates the major part of two streamers combined into one streamer and three streamers arise. The distribution of the reactive oxygen species and the reactive nitrogen species captured by time fluences are non-uniform due to the toe-shaped bacterial biofilms. However, the plasma can intrude into the cavities in the adjacent biofilms due to the μm-scale mean free path. The two streamers case has a larger treatment area and realizes the simultaneous treatment of three biofilms compared with one streamer case.

  14. An investigation of the effect of scaling-induced surface roughness on bacterial adhesion in common fixed dental restorative materials.

    Science.gov (United States)

    Checketts, Matthew R; Turkyilmaz, Ilser; Asar, Neset Volkan

    2014-11-01

    Bacterial plaque must be routinely removed from teeth, adjacent structures, and prostheses. However, the removal of this plaque can inadvertently increase the risk of future bacterial adhesion. The purpose of this investigation was to assess the change in the surface roughness of 3 different surfaces after dental prophylactic instrumentation and how this influenced bacterial adhesion. Forty specimens each of Type III gold alloy, lithium disilicate, and zirconia were fabricated in the same dimensions. The specimens were divided into 4 groups: ultrasonic scaler, stainless steel curette, prophylaxis cup, and control. Pretreatment surface roughness measurements were made with a profilometer. Surface treatments in each group were performed with a custom mechanical scaler. Posttreatment surface roughness values were measured. In turn, the specimens were inoculated with Streptococcus mutans, Lactobacillus acidophilus, and Actinomyces viscosus. Bacterial adhesion was assessed by rinsing the specimens with sterile saline to remove unattached cells. The specimens were then placed in sterile tubes with 1 mL of sterile saline. The solution was plated and quantified. Scanning electron microscopy was performed. The statistical analysis of surface roughness was completed by using repeated-measures single-factor ANOVA with a Bonferroni correction. The surface roughness values for gold alloy specimens increased as a result of prophylaxis cup treatment (0.221 to 0.346 Ra) (Pbacterial adhesion to gold alloy proved inconclusive. A quantitative comparison indicated no statistically significant differences in pretreatment and posttreatment surface roughness values for lithium disilicate and zirconia specimens. In spite of these similarities, the overall bacterial adherence values for lithium disilicate were significantly greater than those recorded for gold alloy or zirconia (PInstrumentation of the lithium disilicate and zirconia with the stainless steel curette significantly increased

  15. MyD88-deficient Hydra reveal an ancient function of TLR signaling in sensing bacterial colonizers.

    Science.gov (United States)

    Franzenburg, Sören; Fraune, Sebastian; Künzel, Sven; Baines, John F; Domazet-Loso, Tomislav; Bosch, Thomas C G

    2012-11-20

    Toll-like receptor (TLR) signaling is one of the most important signaling cascades of the innate immune system of vertebrates. Studies in invertebrates have focused on the fruit fly Drosophila melanogaster and the nematode Caenorhabditis elegans, and there is little information regarding the evolutionary origin and ancestral function of TLR signaling. In Drosophila, members of the Toll-like receptor family are involved in both embryonic development and innate immunity. In C. elegans, a clear immune function of the TLR homolog TOL-1 is controversial and central components of vertebrate TLR signaling including the key adapter protein myeloid differentiation primary response gene 88 (MyD88) and the transcription factor NF-κB are not present. In basal metazoans such as the cnidarians Hydra magnipapillata and Nematostella vectensis, all components of the vertebrate TLR signaling cascade are present, but their role in immunity is unknown. Here, we use a MyD88 loss-of-function approach in Hydra to demonstrate that recognition of bacteria is an ancestral function of TLR signaling and that this process contributes to both host-mediated recolonization by commensal bacteria as well as to defense against bacterial pathogens.

  16. Effect of temperature and colonization of Legionella pneumophila and Vermamoeba vermiformis on bacterial community composition of copper drinking water biofilms.

    Science.gov (United States)

    Buse, Helen Y; Ji, Pan; Gomez-Alvarez, Vicente; Pruden, Amy; Edwards, Marc A; Ashbolt, Nicholas J

    2017-07-01

    It is unclear how the water-based pathogen, Legionella pneumophila (Lp), and associated free-living amoeba (FLA) hosts change or are changed by the microbial composition of drinking water (DW) biofilm communities. Thus, this study characterized the bacterial community structure over a 7-month period within mature (> 600-day-old) copper DW biofilms in reactors simulating premise plumbing and assessed the impact of temperature and introduction of Lp and its FLA host, Vermamoeba vermiformis (Vv), co-cultures (LpVv). Sequence and quantitative PCR (qPCR) analyses indicated a correlation between LpVv introduction and increases in Legionella spp. levels at room temperature (RT), while at 37°C, Lp became the dominant Legionella spp. qPCR analysis suggested Vv presence may not be directly associated with Lp biofilm growth at RT and 37°C, but may contribute to or be associated with non-Lp legionellae persistence at RT. Two-way PERMANOVA and PCoA revealed that temperature was a major driver of microbiome diversity. Biofilm community composition also changed over the seven-month period and could be associated with significant shifts in dissolved oxygen, alkalinity and various metals in the influent DW. Hence, temperature, biofilm age, DW quality and transient intrusions/amplification of pathogens and FLA hosts may significantly impact biofilm microbiomes and modulate pathogen levels over extended periods. © 2016 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  17. An in vivo Study on Bacterial Colonization with Metal, Ceramic and Self-ligating Brackets: A Scanning Electron Microscopy Study

    Directory of Open Access Journals (Sweden)

    Aravind S Raju

    2013-01-01

    Conclusion: This study highlights that higher retention of plaque in ceramic brackets ligated with elastomeric ring followed with metal brackets ligated with steel ligatures and comparatively less plaque retention in self-ligating brackets. Excess composite around the bracket base is the critical site of plaque accumulation associated with fixed appliances due to its rough surface texture.

  18. Claudin-4 Undergoes Age-Dependent Change in Cellular Localization on Pig Jejunal Villous Epithelial Cells, Independent of Bacterial Colonization

    Directory of Open Access Journals (Sweden)

    J. Alex Pasternak

    2015-01-01

    Full Text Available Newborn piglets are immunologically naïve and must receive passive immunity via colostrum within 24 hours to survive. Mechanisms by which the newborn piglet gut facilitates uptake of colostral cells, antibodies, and proteins may include FcRn and pIgR receptor-mediated endocytosis and paracellular transport between tight junctions (TJs. In the present study, FcRn gene (FCGRT was minimally expressed in 6-week-old gut and newborn jejunum but it was expressed at significantly higher levels in the ileum of newborn piglets. pIgR was highly expressed in the jejunum and ileum of 6-week-old animals but only minimally in neonatal gut. Immunohistochemical analysis showed that Claudin-5 localized to blood vessel endothelial cells. Claudin-4 was strongly localized to the apical aspect of jejunal epithelial cells for the first 2 days of life after which it was redistributed to the lateral surface between adjacent enterocytes. Claudin-4 was localized to ileal lateral surfaces within 24 hours after birth indicating regional and temporal differences. Tissue from gnotobiotic piglets showed that commensal microbiota did not influence Claudin-4 surface localization on jejunal or ileal enterocytes. Regulation of TJs by Claudin-4 surface localization requires further investigation. Understanding the factors that regulate gut barrier maturation may yield protective strategies against infectious diseases.

  19. Bacterial strategies of resistance to antimicrobial peptides.

    Science.gov (United States)

    Joo, Hwang-Soo; Fu, Chih-Iung; Otto, Michael

    2016-05-26

    Antimicrobial peptides (AMPs) are a key component of the host's innate immune system, targeting invasive and colonizing bacteria. For successful survival and colonization of the host, bacteria have a series of mechanisms to interfere with AMP activity, and AMP resistance is intimately connected with the virulence potential of bacterial pathogens. In particular, because AMPs are considered as potential novel antimicrobial drugs, it is vital to understand bacterial AMP resistance mechanisms. This review gives a comparative overview of Gram-positive and Gram-negative bacterial strategies of resistance to various AMPs, such as repulsion or sequestration by bacterial surface structures, alteration of membrane charge or fluidity, degradation and removal by efflux pumps.This article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'. © 2016 The Author(s).

  20. Surface tailored organobentonite enhances bacterial proliferation and phenanthrene biodegradation under cadmium co-contamination

    Energy Technology Data Exchange (ETDEWEB)

    Mandal, Asit [Future Industries Institute (formerly Centre for Environmental Risk Assessment and Remediation), University of South Australia, Mawson Lakes, SA 5095 (Australia); Indian Council of Agricultural Research (ICAR), Indian Institute of Soil Science, Bhopal (India); Biswas, Bhabananda [Future Industries Institute (formerly Centre for Environmental Risk Assessment and Remediation), University of South Australia, Mawson Lakes, SA 5095 (Australia); Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), ACT Building, University of Newcastle, Callaghan, NSW 2308 (Australia); Sarkar, Binoy, E-mail: binoy.sarkar@unisa.edu.au [Future Industries Institute (formerly Centre for Environmental Risk Assessment and Remediation), University of South Australia, Mawson Lakes, SA 5095 (Australia); Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), ACT Building, University of Newcastle, Callaghan, NSW 2308 (Australia); Patra, Ashok K. [Indian Council of Agricultural Research (ICAR), Indian Institute of Soil Science, Bhopal (India); Naidu, Ravi, E-mail: ravi.naidu@newcastle.edu.au [Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), ACT Building, University of Newcastle, Callaghan, NSW 2308 (Australia); Global Centre for Environmental Remediation (GCER), Faculty of Science and Information Technology, University of Newcastle, Callaghan, NSW 2308 (Australia)

    2016-04-15

    Co-contamination of soil and water with polycyclic aromatic hydrocarbon (PAH) and heavy metals makes biodegradation of the former extremely challenging. Modified clay-modulated microbial degradation provides a novel insight in addressing this issue. This study was conducted to evaluate the growth and phenanthrene degradation performance of Mycobacterium gilvum VF1 in the presence of a palmitic acid (PA)-grafted Arquad® 2HT-75-based organobentonite in cadmium (Cd)-phenanthrene co-contaminated water. The PA-grafted organobentonite (ABP) adsorbed a slightly greater quantity of Cd than bentonite at up to 30 mg L{sup −1} metal concentration, but its highly negative surface charge imparted by carboxylic groups indicated the potential of being a significantly superior adsorbent of Cd at higher metal concentrations. In systems co-contained with Cd (5 and 10 mg L{sup −1}), the Arquad® 2HT-75-modified bentonite (AB) and PA-grafted organobentonite (ABP) resulted in a significantly higher (72–78%) degradation of phenanthrene than bentonite (62%) by the bacterium. The growth and proliferation of bacteria were supported by ABP which not only eliminated Cd toxicity through adsorption but also created a congenial microenvironment for bacterial survival. The macromolecules produced during ABP–bacteria interaction could form a stable clay-bacterial cluster by overcoming the electrostatic repulsion among individual components. Findings of this study provide new insights for designing clay modulated PAH bioremediation technologies in mixed-contaminated water and soil. - Highlights: • Surface tailored organobentonite synthesised and characterised • Modified clay adsorbs Cd and reduces toxicity to Mycobacterium gilvum. • It creates congenial microenvironment for bacterial survival. • It enhances phenanthrene biodegradation in metal co-contaminated condition.

  1. Bacterial adherence in otitis media: Determination of N-acetylgalactosamine (GalNAc) residues in the submucosal glands and surface epithelium of the normal and diseased Eustachian tube

    DEFF Research Database (Denmark)

    Kirkeby, S; Friis, M; Mikkelsen, H B

    2011-01-01

    Acute otitis media (AOM) is the most common childhood infection caused by bacteria. The pathogenesis of AOM implicates initial adherence of a pathogen to the nasopharyngeal epithelium, which is followed by bacterial colonization of the middle ear cavity through the Eustachian tube. N-acetylgalact......Acute otitis media (AOM) is the most common childhood infection caused by bacteria. The pathogenesis of AOM implicates initial adherence of a pathogen to the nasopharyngeal epithelium, which is followed by bacterial colonization of the middle ear cavity through the Eustachian tube. N...

  2. Comparison of bacterial cells and amine-functionalized abiotic surfaces as support for Pd nanoparticle synthesis

    DEFF Research Database (Denmark)

    De Corte, Simon; Bechstein, Stefanie; Lokanathan, Arcot R.

    2013-01-01

    An increasing demand for catalytic Pd nanoparticles has motivated the search for sustainable production methods. An innovative approach uses bacterial cells as support material for synthesizing Pd nanoparticles by reduction of Pd(II) with e.g. hydrogen or formate. Nevertheless, drawbacks...... nanoparticles, and that abiotic surfaces could support the Pd particle synthesis as efficiently as bacteria. In this study, we explore the possibility of replacing bacteria with amine-functionalized materials, and we compare different functionalization strategies. Pd nanoparticles formed on the support...... on these surfaces was higher than for Pd particles formed on Shewanella oneidensis cells. Smaller Pd nanoparticles generally have better catalytic properties, and previous studies have shown that the particle size can be lowered by increasing the amount of support material used during Pd particle formation. However...

  3. Inactivation of bacterial and viral biothreat agents on metallic copper surfaces.

    Science.gov (United States)

    Bleichert, Pauline; Espírito Santo, Christophe; Hanczaruk, Matthias; Meyer, Hermann; Grass, Gregor

    2014-12-01

    In recent years several studies in laboratory settings and in hospital environments have demonstrated that surfaces of massive metallic copper have intrinsic antibacterial and antiviral properties. Microbes are rapidly inactivated by a quick, sharp shock known as contact killing. The underlying mechanism is not yet fully understood; however, in this process the cytoplasmic membrane is severely damaged. Pathogenic bacterial and viral high-consequence species able to evade the host immune system are among the most serious lethal microbial challenges to human health. Here, we investigated contact-killing mediated by copper surfaces of Gram-negative bacteria (Brucella melitensis, Burkholderia mallei, Burkholderia pseudomallei, Francisella tularensis tularensis and Yersinia pestis) and of Gram-positive endospore-forming Bacillus anthracis. Additionally, we also tested inactivation of monkeypox virus and vaccinia virus on copper. This group of pathogens comprises biothreat species (or their close relatives) classified by the Center for Disease and Control and Prevention (CDC) as microbial select agents posing severe threats to public health and having the potential to be deliberately released. All agents were rapidly inactivated on copper between 30 s and 5 min with the exception of B. anthracis endospores. For vegetative bacterial cells prolonged contact to metallic copper resulted in the destruction of cell structure.

  4. Bacterial communities of surface and deep hydrocarbon-contaminated waters of the Deepwater Horizon oil spill

    Science.gov (United States)

    Yang, T.; Nigro, L. M.; McKay, L.; Ziervogel, K.; Gutierrez, T.; Teske, A.

    2010-12-01

    We performed a 16S rRNA gene sequencing survey of bacterial communities within oil-contaminated surface water, deep hydrocarbon plume water, and deep water samples above and below the plume to determine spatial and temporal patterns of oil-degrading bacteria growing in response to the Deepwater Horizon oil leak. In addition, we are reporting 16S rRNA sequencing results from time series incubation, enrichment and cultivation experiments. Surface oil slick samples were collected 3 nautical miles from ground zero, (5/6/10, RV Pelican) and were added to uncontaminated surface water (collected within a 30 nautical mile radius of ground zero, 5/6/10 - 5/9/10, RV Pelican). This mixture was incubated for 20 days in a rolling bottle at 25°C. 16S rRNA clone libraries from marine snow-like microbial flocs that had formed during the incubation yielded a highly diverse bacterial community, predominately composed of the Alpha- and Gammaproteobacteria, and a smaller number of Planktomycetes and other bacterial lineages. The most frequently recovered proteobacterial sequences were closely related to cultured species of the genus Cycloclasticus, specialists in aerobic oxidation of aromatic hydrocarbons. These time series incubation results will be compared to the microbial community structure of contaminated surface water, sampled on the same cruise with RV Pelican (5/6/10-5/9/10) and frozen immediately. Stable isotope probing (SIP) experiments with C13-labelled alkanes and polycyclic aromatic substrates and gulf water samples have yielded different enrichments. With naphthalene, predominantly Alteromonas-related clones and a smaller share of Cycloclasticus clones were recovered; phenanthrene yielded predominantly clones related to Cycloclasticus, and diverse other Gamma- and Alphaproteobacteria. Analyses of SIP experiments with hexadecane are in progress. The microbial community composition of the deep hydrocarbon plume was characterized using water column profile samples taken

  5. Bacterial Ghosts as antigen and drug delivery system for ocular surface diseases: Effective internalization of Bacterial Ghosts by human conjunctival epithelial cells.

    Science.gov (United States)

    Kudela, Pavol; Koller, Verena Juliana; Mayr, Ulrike Beate; Nepp, Johannes; Lubitz, Werner; Barisani-Asenbauer, Talin

    2011-05-20

    The purpose of the presented investigation was to examine the efficiency of the novel carrier system Bacterial Ghosts (BGs), which are empty bacterial cell envelopes of Gram-negative bacteria to target human conjunctival epithelial cells, as well as to test the endocytic capacity of conjunctival cells after co-incubation with BGs generated from different bacterial species, and to foreclose potential cytotoxic effects caused by BGs. The efficiency of conjunctival cells to internalize BGs was investigated using the Chang conjunctival epithelial cell line and primary human conjunctiva-derived epithelial cells (HCDECs) as in vitro model. A high capacity of HCDECs to functionally internalize BGs was detected with the level of internalization depending on the type of species used for BGs generation. Detailed analysis showed no cytotoxic effect of BGs on HCDECs independently of the used bacterial species. Moreover, co-incubation with BGs did not enhance expression of both MHC class I and class II molecules by HCDECs, but increased expression of ICAM-1. The high rates of BG's internalization by HCDECs with no BG-mediated cytotoxic impact designate this carrier system to be a promising candidate for an ocular surface drug delivery system. BGs could be useful for future therapeutic ocular surface applications and eye-specific disease vaccine development including DNA transfer. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Proteomic inventory of "anchorless" proteins on the colon adenocarcinoma cell surface.

    NARCIS (Netherlands)

    Tjalsma, H.; Pluk, W.J.G.; Heuvel, L.P.W.J. van den; Peters, W.H.M.; Roelofs, R.H.W.M.; Swinkels, D.W.

    2006-01-01

    Surface proteins play important pathophysiological roles in health and disease, and accumulating proteomics-based studies suggest that several "non-membrane" proteins are sorted to the cell surface by unconventional mechanisms. Importantly, these proteins may comprise attractive therapeutic targets

  7. Colonic Polyps

    Science.gov (United States)

    ... Colonic polyps grow in the large intestine, or colon. Most polyps are not dangerous. However, some polyps ... member with polyps Have a family history of colon cancer Most colon polyps do not cause symptoms. ...

  8. Bacterial whole-cell biocatalysts by surface display of enzymes: toward industrial application.

    Science.gov (United States)

    Schüürmann, Jan; Quehl, Paul; Festel, Gunter; Jose, Joachim

    2014-10-01

    Despite the first report on the bacterial display of a recombinant peptide appeared almost 30 years ago, industrial application of cells with surface-displayed enzymes is still limited. To display an enzyme on the surface of a living cell bears several advantages. First of all, neither the substrate nor the product of the enzymatic reaction needs to cross a membrane barrier. Second, the enzyme being linked to the cell can be separated from the reaction mixture and hence the product by simple centrifugation. Transfer to a new substrate preparation results in multiple cycles of enzymatic conversion. Finally, the anchoring in a matrix, in this case, the cell envelope stabilizes the enzyme and makes it less accessible to proteolytic degradation and material adsorption resulting in continuous higher activities. These advantages in common need to balance some disadvantages before this application can be taken into account for industrial processes, e.g., the exclusion of the enzyme from the cellular metabolome and hence from redox factors or other co-factors that need to be supplied. Therefore, this digest describes the different systems in Gram-positive and Gram-negative bacteria that have been used for the surface display of enzymes so far and focuses on examples among these which are suitable for industrial purposes or for the production of valuable resources, not least in order to encourage a broader application of whole-cell biocatalysts with surface-displayed enzymes.

  9. Bacterial adherence on fluorinated carbon based coatings deposited on polyethylene surfaces

    International Nuclear Information System (INIS)

    Terriza, A; Del Prado, G; Perez, A Ortiz; Martinez, M J; Puertolas, J A; Manso, D Molina; Gonzalez-Elipe, A R; Yubero, F; Barrena, E Gomez; Esteban, J

    2010-01-01

    Development of intrinsically antibacterial surfaces is of key importance in the context of prostheses used in orthopaedic surgery. In this work we present a thorough study of several plasma based coatings that may be used with this functionality: diamond like carbon (DLC), fluorine doped DLC (F-DLC) and a high fluorine content carbon-fluor polymer (CF X ). The study correlates the surface chemistry and hydrophobicity of the coating surfaces with their antibacterial performance. The coatings were deposited by RF-plasma assisted deposition at room temperature on ultra high molecular weight polyethylene (UHMWPE) samples. Fluorine content and relative amount of C-C and C-F bond types was monitored by X-ray photoelectron spectroscopy and hydrophobicity by water contact angle measurements. Adherence of Staphylococcus aureus and Staphylococcus epidermidis to non-coated and coated UHMWPE samples was evaluated. Comparisons of the adherence performance were evaluated using a paired t test (two materials) and a Kruskall Wallis test (all the materials). S. aureus was statistically significant (p< 0.001) less adherent to DLC and F-DLC surfaces than S. epidermidis. Both bacteria showed reduction of adherence on DLC/UHMWPE. For S. aureus, reduction of bacterial adherence on F-DLC/UHMWPE was statistically significant respect to all other materials.

  10. Longevity in mice is promoted by probiotic-induced suppression of colonic senescence dependent on upregulation of gut bacterial polyamine production.

    Directory of Open Access Journals (Sweden)

    Mitsuharu Matsumoto

    Full Text Available BACKGROUND: Chronic low-grade inflammation is recognized as an important factor contributing to senescence and age-related diseases. In mammals, levels of polyamines (PAs decrease during the ageing process; PAs are known to decrease systemic inflammation by inhibiting inflammatory cytokine synthesis in macrophages. Reductions in intestinal luminal PAs levels have been associated with intestinal barrier dysfunction. The probiotic strain Bifidobacterium animalis subsp. lactis LKM512 is known to increase intestinal luminal PA concentrations. METHODOLOGY/PRINCIPAL FINDINGS: We supplemented the diet of 10-month-old Crj:CD-1 female mice with LKM512 for 11 months, while the controls received no supplementation. Survival rates were compared using Kaplan-Meier survival curves. LKM512-treated mice survived significantly longer than controls (P<0.001; moreover, skin ulcers and tumors were more common in the control mice. We then analyzed inflammatory and intestinal conditions by measuring several markers using HPLC, ELISA, reverse transcription-quantitative PCR, and histological slices. LKM512 mice showed altered 16S rRNA gene expression of several predominant intestinal bacterial groups. The fecal concentrations of PAs, but not of short-chain fatty acids, were significantly higher in LKM512-treated mice (P<0.05. Colonic mucosal function was also better in LKM512 mice, with increased mucus secretion and better maintenance of tight junctions. Changes in gene expression levels were evaluated using the NimbleGen mouse DNA microarray. LKM512 administration also downregulated the expression of ageing-associated and inflammation-associated genes and gene expression levels in 21-month-old LKM512-treated mice resembled those in 10-month-old untreated (younger mice. CONCLUSION/SIGNIFICANCE: Our study demonstrated increased longevity in mice following probiotic treatment with LKM512, possibly due to the suppression of chronic low-grade inflammation in the colon

  11. Modulating the bacterial surface with small RNAs: a new twist on PhoP/Q-mediated lipopolysaccharide modification

    DEFF Research Database (Denmark)

    Overgaard, Martin; Kallipolitis, Birgitte; Valentin-Hansen, Poul

    2009-01-01

    Summary In recent years, small non-coding RNAs have emerged as important regulatory components in bacterial stress responses and in bacterial virulence. Many of these are conserved in related species and act on target mRNAs by sequence complementarity. They are tightly controlled...... of bacterial surface properties by regulating lipopolysaccharide modification. The small RNA is expressed as part of the PhoP/PhoQ two-component system that plays a major role in virulence of pathogenic species. This work expands the list of global regulators known to control small RNA expression...

  12. Surface charge-conversion polymeric nanoparticles for photodynamic treatment of urinary tract bacterial infections

    International Nuclear Information System (INIS)

    Liu, Shijie; Shao, Chen; Qiao, Shenglin; Li, Lili; Qi, Guobin; Lin, Yaoxin; Qiao, Zengying; Wang, Hao

    2015-01-01

    Urinary tract infections are typical bacterial infections which result in a number of economic burdens. With increasing antibiotic resistance, it is urgent that new approaches are explored that can eliminate pathogenic bacteria without inducing drug resistance. Antimicrobial photodynamic therapy (PDT) is a new promising tactic. It is a gentle in situ photochemical reaction in which a photosensitizer (PS) generates reactive oxygen species (ROS) under laser irradiation. In this work, we have demonstrated Chlorin e6 (Ce6) encapsulated charge-conversion polymeric nanoparticles (NPs) for efficiently targeting and killing pathogenic bacteria in a weakly acidic urinary tract infection environment. Owing to the surface charge conversion of NPs in an acidic environment, the NPs exhibited enhanced recognition for Gram-positive (ex. S. aureus) and Gram-negative (ex. E. coli) bacteria due to the charge interaction. Also, those NPs showed significant antibacterial efficacy in vitro with low cytotoxicity. The MIC value of NPs to E. coli is 17.91 μg ml −1 , compared with the free Ce6 value of 29.85 μg ml −1 . Finally, a mouse acute cystitis model was used to assess the photodynamic therapy effects in urinary tract infections. A significant decline (P < 0.05) in bacterial cells between NPs and free Ce6 occurred in urine after photodynamic therapy treatment. And the plated counting results revealed a remarkable bacterial cells drop (P < 0.05) in the sacrificed bladder tissue. Above all, this nanotechnology strategy opens a new door for the treatment of urinary tract infections with minimal side effects. (paper)

  13. Surface charge-conversion polymeric nanoparticles for photodynamic treatment of urinary tract bacterial infections

    Science.gov (United States)

    Liu, Shijie; Qiao, Shenglin; Li, Lili; Qi, Guobin; Lin, Yaoxin; Qiao, Zengying; Wang, Hao; Shao, Chen

    2015-12-01

    Urinary tract infections are typical bacterial infections which result in a number of economic burdens. With increasing antibiotic resistance, it is urgent that new approaches are explored that can eliminate pathogenic bacteria without inducing drug resistance. Antimicrobial photodynamic therapy (PDT) is a new promising tactic. It is a gentle in situ photochemical reaction in which a photosensitizer (PS) generates reactive oxygen species (ROS) under laser irradiation. In this work, we have demonstrated Chlorin e6 (Ce6) encapsulated charge-conversion polymeric nanoparticles (NPs) for efficiently targeting and killing pathogenic bacteria in a weakly acidic urinary tract infection environment. Owing to the surface charge conversion of NPs in an acidic environment, the NPs exhibited enhanced recognition for Gram-positive (ex. S. aureus) and Gram-negative (ex. E. coli) bacteria due to the charge interaction. Also, those NPs showed significant antibacterial efficacy in vitro with low cytotoxicity. The MIC value of NPs to E. coli is 17.91 μg ml-1, compared with the free Ce6 value of 29.85 μg ml-1. Finally, a mouse acute cystitis model was used to assess the photodynamic therapy effects in urinary tract infections. A significant decline (P < 0.05) in bacterial cells between NPs and free Ce6 occurred in urine after photodynamic therapy treatment. And the plated counting results revealed a remarkable bacterial cells drop (P < 0.05) in the sacrificed bladder tissue. Above all, this nanotechnology strategy opens a new door for the treatment of urinary tract infections with minimal side effects.

  14. Bacterial adhesion on conventional and self-ligating metallic brackets after surface treatment with plasma-polymerized hexamethyldisiloxane

    Directory of Open Access Journals (Sweden)

    Rogerio Amaral Tupinambá

    Full Text Available ABSTRACT Introduction: Plasma-polymerized film deposition was created to modify metallic orthodontic brackets surface properties in order to inhibit bacterial adhesion. Methods: Hexamethyldisiloxane (HMDSO polymer films were deposited on conventional (n = 10 and self-ligating (n = 10 stainless steel orthodontic brackets using the Plasma-Enhanced Chemical Vapor Deposition (PECVD radio frequency technique. The samples were divided into two groups according to the kind of bracket and two subgroups after surface treatment. Scanning Electron Microscopy (SEM analysis was performed to assess the presence of bacterial adhesion over samples surfaces (slot and wings region and film layer integrity. Surface roughness was assessed by Confocal Interferometry (CI and surface wettability, by goniometry. For bacterial adhesion analysis, samples were exposed for 72 hours to a Streptococcus mutans solution for biofilm formation. The values obtained for surface roughness were analyzed using the Mann-Whitney test while biofilm adhesion were assessed by Kruskal-Wallis and SNK test. Results: Significant statistical differences (p 0.05. Conclusion: Plasma-polymerized film deposition was only effective on reducing surface roughness and bacterial adhesion in conventional brackets. It was also noted that conventional brackets showed lower biofilm adhesion than self-ligating brackets despite the absence of film.

  15. Bacterial adhesion on conventional and self-ligating metallic brackets after surface treatment with plasma-polymerized hexamethyldisiloxane

    Science.gov (United States)

    Tupinambá, Rogerio Amaral; Claro, Cristiane Aparecida de Assis; Pereira, Cristiane Aparecida; Nobrega, Celestino José Prudente; Claro, Ana Paula Rosifini Alves

    2017-01-01

    ABSTRACT Introduction: Plasma-polymerized film deposition was created to modify metallic orthodontic brackets surface properties in order to inhibit bacterial adhesion. Methods: Hexamethyldisiloxane (HMDSO) polymer films were deposited on conventional (n = 10) and self-ligating (n = 10) stainless steel orthodontic brackets using the Plasma-Enhanced Chemical Vapor Deposition (PECVD) radio frequency technique. The samples were divided into two groups according to the kind of bracket and two subgroups after surface treatment. Scanning Electron Microscopy (SEM) analysis was performed to assess the presence of bacterial adhesion over samples surfaces (slot and wings region) and film layer integrity. Surface roughness was assessed by Confocal Interferometry (CI) and surface wettability, by goniometry. For bacterial adhesion analysis, samples were exposed for 72 hours to a Streptococcus mutans solution for biofilm formation. The values obtained for surface roughness were analyzed using the Mann-Whitney test while biofilm adhesion were assessed by Kruskal-Wallis and SNK test. Results: Significant statistical differences (p 0.05). Conclusion: Plasma-polymerized film deposition was only effective on reducing surface roughness and bacterial adhesion in conventional brackets. It was also noted that conventional brackets showed lower biofilm adhesion than self-ligating brackets despite the absence of film. PMID:28902253

  16. [Bacterial biofilms on PVC tubing's inner surface of hemodialysis water treatment system].

    Science.gov (United States)

    Yang, Sha; Jia, Ke; Peng, Youming; Liu, Hong; Liu, Yinghong; Chen, Xing; Liu, Fuyou

    2009-10-01

    To determine the morphology, bacteria and endotoxin content of biofilms on the inner surface of PVC tubes in hemodialysis water treatment system. We dissolved biofilms of segments before and after reverse osmosis machine for bacterial count and identification. We studied biofilm structure of segments before and after reverse osmosis machine with eyes and scanning electron microscope. Biofilms of all 7 segments were dissolved for qualitative and quantitative assay of endotoxin. The inner surface of segment before reverse osmosis machine was homogeneously distributed with activated carbon powder deposition. The segment after reverse osmosis machine was normal. With scanning electron microscope, biofilm with successive surface and sandwich was found on the inner surface of segment before reverse osmosis machine, formed by clustering bacillus, activated carbon powder and some coccus. Bacteria of the same shape and length were found on segment after reverse osmosis machine, but fewer and looser. Bacterial culture and identification showed the former was mostly gram-negative bacillus, the latter was only a few micrococcus. Endotoxin of biofilm was between 2.0 EU/mL and 4.0 EU/mL. Quantitative assay showed: segment after softener (2.821+/-0.807) EU/mL; segment after active charcoal canister(3.635+/-0.427) EU/mL; segment before reverse osmosis machine (3.687+/-0.271) EU/mL; segment after reverse osmosis machine (2.041+/-0.295) EU/mL; exit of power pump (1.983+/-0.390)EU/mL;the 1st dead space (2.373+/-0.535) EU/mL; and the 2nd dead space (2.858+/-0.690)EU/mL. Biofilms are found on the inner surface of segment before and after reverse osmosis machine. Endotoxin level from high to low is as follows: segment before reverse osmosis machine, segment after active charcoal canister, the 2nd dead space, segment after softener, the 1st dead space, segment after reverse osmosis machine, exit of power pump. The character of the bacteria and endotoxin of the biofilm can help us find

  17. Gamma-polyglutamic acid (gamma-PGA) produced by Bacillus amyloliquefaciens C06 promoting its colonization on fruit surface.

    Science.gov (United States)

    Liu, Jun; He, Dan; Li, Xiu-zhen; Gao, Shengfeng; Wu, Huijun; Liu, Wenzhe; Gao, Xuewen; Zhou, Ting

    2010-08-15

    Bacillus amyloliquefaciens C06, an effective biological agent in controlling brown rot of stone fruit caused by Monilinia fructicola, was also found to produce extra-cellular mucilage and form mucoid colonies on semi-solid surfaces. This study aimed to characterize the extra-cellular mucilage produced by B. amyloliquefaciens C06 using transposon mutagenesis and biochemical and physical analyses. The mucilage production in B. amyloliquefaciens C06 was demonstrated to be associated with ywsC gene expression and characterized to be of high molecular weight, consisted of only glutamic acid and linked with non-peptide bonds, thus identified as gamma-polyglutamic acid (gamma-PGA). Compared with wild type B. amyloliquefaciens C06, its mutants deficient in producing gamma-PGA, e.g. M106 and C06DeltaywsC showed less efficiency in biofilm formation, surface adhesion and swarming ability. It was also demonstrated that gamma-PGA was not essential for C06 to form colony on semi-solid surfaces, but was able to improve its colony structure. In vivo evaluation showed that disruption of gamma-PGA production in C06DeltaywsC impaired its efficiency of colonizing apple surfaces. Copyright 2010 Elsevier B.V. All rights reserved.

  18. Preparation of miniantibodies to Azospirillum brasilense Sp245 surface antigens and their use for bacterial detection.

    Science.gov (United States)

    Dykman, Lev A; Staroverov, Sergei A; Guliy, Olga I; Ignatov, Oleg V; Fomin, Alexander S; Vidyasheva, Irina V; Karavaeva, Olga A; Bunin, Viktor D; Burygin, Gennady L

    2012-01-01

    This article reports the first preparation of miniantibodies to Azospirillum brasilense Sp245 surface antigens by using a combinatorial phage library of sheep antibodies. The prepared phage antibodies were used for the first time for lipopolysaccharide and flagellin detection by dot assay, electro-optical analysis of cell suspensions, and transmission electron microscopy. Interaction of A. brasilense Sp245 with antilipopolysaccharide and antiflagellin phage-displayed miniantibodies caused the magnitude of the electro-optical signal to change considerably. The electro-optical results were in good agreement with the electron microscopic data. This is the first reported possibility of employing phage-displayed miniantibodies in bacterial detection aided by electro-optical analysis of cell suspensions.

  19. Mechanisms of recurrent otitis media: importance of the immune response to bacterial surface antigens.

    Science.gov (United States)

    Murphy, T F; Yi, K

    1997-12-29

    Otitis-prone children experience recurrent episodes of otitis media due to nontypeable H. influenzae (NTHI). A protective immune response occurs following infection, but this immune response is specific for the infecting strain, leaving the child susceptible to infection by other strains of NTHI. Little is known about the mechanism by which a strain-specific antibody response occurs to nonencapsulated bacteria. To explore the mechanism by which this strain-specific response occurs, animals were inoculated with whole bacterial cells and the antibody response was studied. The antibody response was predominantly directed to a highly strain-specific, immunodominant surface loop on the major outer membrane protein. This exquisitely restricted immune response leaves the host susceptible to recurrent infections by many strains of NTHI. The ability of the bacterium to direct the host to make a strain-specific antibody response has important implications in understanding the immune response to otitis media due to NTHI and in designing strategies for vaccine development.

  20. Monodisperse gold nanoparticles formed on bacterial crystalline surface layers (S-layers) by electroless deposition

    Energy Technology Data Exchange (ETDEWEB)

    Dieluweit, S. [Center for Nanobiotechnology, University of Natural Resources and Applied Life Sciences (BOKU), Gregor Mendel-Strasse 33, A-1180 Vienna (Austria); Pum, D. [Center for Nanobiotechnology, University of Natural Resources and Applied Life Sciences (BOKU), Gregor Mendel-Strasse 33, A-1180 Vienna (Austria); Sleytr, U.B. [Center for Nanobiotechnology, University of Natural Resources and Applied Life Sciences (BOKU), Gregor Mendel-Strasse 33, A-1180 Vienna (Austria); Kautek, W. [Department for Physical Chemistry, University of Vienna, Waehringer Strasse 42, A-1090 Vienna (Austria)]. E-mail: wolfgang.kautek@univie.ac.at

    2005-12-15

    The fabrication of patterned arrays of nanoparticles whose electronic, optical and magnetic properties will find technological applications, such as ultra-high-density memories, is currently one of the most important objectives of inorganic material research. In this study, the in situ electroless nucleation of ordered two-dimensional arrays of gold nanoparticles (5 nm in size) by using bacterial S-layers as molecular templates and their characterization by small spot X-ray photoelectron emission spectroscopy (XPS) is presented. This yielded the elemental composition of the nanoclusters, which consisted of almost entirely elemental gold, and possible side reactions on the cluster and protein surface. The preferential deposition of the gold nanoparticles on the S-layer suggests that topography and functional groups are important for superlattice formation.

  1. Chemical mediation of bacterial surface colonisation by secondary metabolites from the red alga Delisea pulchra

    DEFF Research Database (Denmark)

    Maximilien, Ria; de Nys, Rocky; Holmström, Carola

    1998-01-01

    experimentally investigated inhibition of marine bacteria by furanones, initially testing the effects of crude extract of D. pulchra (about 50 % of which is furanones) on the growth of 144 strains of bacteria isolated from the surfaces of D. pulchra, nearby rocks, or a co-occurring alga (Sasgassum vestitum......). This crude extract did not strongly inhibit growth of these bacteria; 79% of the strains grew at 50 pg ml(-1) of crude extract, and 63 % grew at 500 mu g ml(-1). Inhibition of growth that did occur was strongly source dependent, with bacteria isolated from rocks the least affected, and strains from D...... - attachment, swarming, and swimming. Individual furanones or crude extract at natural concentrations strongly inhibited bacterial attachment in the laboratory and in the field. In laboratory assays, attachment of 3 strains isolated from rocks was much more strongly affected than that of 3 isolates from D...

  2. Rapid bacterial antibiotic susceptibility test based on simple surface-enhanced Raman spectroscopic biomarkers

    Science.gov (United States)

    Liu, Chia-Ying; Han, Yin-Yi; Shih, Po-Han; Lian, Wei-Nan; Wang, Huai-Hsien; Lin, Chi-Hung; Hsueh, Po-Ren; Wang, Juen-Kai; Wang, Yuh-Lin

    2016-03-01

    Rapid bacterial antibiotic susceptibility test (AST) and minimum inhibitory concentration (MIC) measurement are important to help reduce the widespread misuse of antibiotics and alleviate the growing drug-resistance problem. We discovered that, when a susceptible strain of Staphylococcus aureus or Escherichia coli is exposed to an antibiotic, the intensity of specific biomarkers in its surface-enhanced Raman scattering (SERS) spectra drops evidently in two hours. The discovery has been exploited for rapid AST and MIC determination of methicillin-susceptible S. aureus and wild-type E. coli as well as clinical isolates. The results obtained by this SERS-AST method were consistent with that by the standard incubation-based method, indicating its high potential to supplement or replace existing time-consuming methods and help mitigate the challenge of drug resistance in clinical microbiology.

  3. Comparing the ocular surface effects of topical vancomycin and linezolid for treating bacterial keratitis.

    Science.gov (United States)

    Akova Budak, Berna; Baykara, Mehmet; Kıvanç, Sertaç Argun; Yilmaz, Hakan; Cicek, Serhat

    2016-01-01

    Vancomycin is the gold standard in combination therapy for severe and resistant gram-positive keratitis and in particular for Methicillin-resistant Staphylococcus aureus (MRSA) infections. The aim of this study was to report the ocular surface toxicity and scoring in patients whose treatment shifted to topical linezolid/ceftazidime from topical vancomycin/ceftazidime due to their vancomycin intolerance. A retrospective, interventional case series of bacterial keratitis was treated with topical linezolid (one drop of 0.2% solution per eye), administered hourly until epithelization and then gradually decreased. The number and extent of punctate epithelial erosions were noted across the entire surface of the cornea. Ocular discomfort was assessed by means of (a) patient-reported pain upon instillation of the medication (vancomycin/linezolid), (b) reported burning sensation between doses and (c) reported foreign-body sensation. No ocular surface toxicity related to linezolid use was noted. Patients were followed for at least 2 months after treatment between April and December 2013. Of the seven patients included in the study (age range: 2-88 years; five females, two males), complete epithelization and resolution was achieved in five patients. One patient was treated with linezolid after penetrating keratoplasty. The second culture of another patient with impending perforation despite linezolid/ceftazidime therapy yielded Fusarium spp., so he underwent tectonic keratoplasty. The mean ocular surface score was 9.4 ± 1.6 during vancomycin treatment and 5.9 ± 1.3 during linezolid treatment after discontinuation of vancomycin. The topical linezolid score was significantly lower (p = 0.027). Topical linezolid may be better tolerated, according to the mean ocular surface score, than topical vancomycin by some patients and can be considered an alternative for patients who do not well tolerate vancomycin.

  4. Decolorization of industrial synthetic dyes using engineered Pseudomonas putida cells with surface-immobilized bacterial laccase

    Science.gov (United States)

    2012-01-01

    Background Microbial laccases are highly useful in textile effluent dye biodegradation. However, the bioavailability of cellularly expressed or purified laccases in continuous operations is usually limited by mass transfer impediment or enzyme regeneration difficulty. Therefore, this study develops a regenerable bacterial surface-displaying system for industrial synthetic dye decolorization, and evaluates its effects on independent and continuous operations. Results A bacterial laccase (WlacD) was engineered onto the cell surface of the solvent-tolerant bacterium Pseudomonas putida to construct a whole-cell biocatalyst. Ice nucleation protein (InaQ) anchor was employed, and the ability of 1 to 3 tandemly aligned N-terminal repeats to direct WlacD display were compared. Immobilized WlacD was determined to be surface-displayed in functional form using Western blot analysis, immunofluorescence microscopy, flow cytometry, and whole-cell enzymatic activity assay. Engineered P. putida cells were then applied to decolorize the anthraquinone dye Acid Green (AG) 25 and diazo-dye Acid Red (AR) 18. The results showed that decolorization of both dyes is Cu2+- and mediator-independent, with an optimum temperature of 35°C and pH of 3.0, and can be stably performed across a temperature range of 15°C to 45°C. A high activity toward AG25 (1 g/l) with relative decolorization values of 91.2% (3 h) and 97.1% (18 h), as well as high activity to AR18 (1 g/l) by 80.5% (3 h) and 89.0% (18 h), was recorded. The engineered system exhibited a comparably high activity compared with those of separate dyes in a continuous three-round shake-flask decolorization of AG25/AR18 mixed dye (each 1 g/l). No significant decline in decolorization efficacy was noted during first two-rounds but reaction equilibriums were elongated, and the residual laccase activity eventually decreased to low levels. However, the decolorizing capacity of the system was easily retrieved via a subsequent 4-h

  5. Decolorization of industrial synthetic dyes using engineered Pseudomonas putida cells with surface-immobilized bacterial laccase

    Directory of Open Access Journals (Sweden)

    Wang Wei

    2012-06-01

    Full Text Available Abstract Background Microbial laccases are highly useful in textile effluent dye biodegradation. However, the bioavailability of cellularly expressed or purified laccases in continuous operations is usually limited by mass transfer impediment or enzyme regeneration difficulty. Therefore, this study develops a regenerable bacterial surface-displaying system for industrial synthetic dye decolorization, and evaluates its effects on independent and continuous operations. Results A bacterial laccase (WlacD was engineered onto the cell surface of the solvent-tolerant bacterium Pseudomonas putida to construct a whole-cell biocatalyst. Ice nucleation protein (InaQ anchor was employed, and the ability of 1 to 3 tandemly aligned N-terminal repeats to direct WlacD display were compared. Immobilized WlacD was determined to be surface-displayed in functional form using Western blot analysis, immunofluorescence microscopy, flow cytometry, and whole-cell enzymatic activity assay. Engineered P. putida cells were then applied to decolorize the anthraquinone dye Acid Green (AG 25 and diazo-dye Acid Red (AR 18. The results showed that decolorization of both dyes is Cu2+- and mediator-independent, with an optimum temperature of 35°C and pH of 3.0, and can be stably performed across a temperature range of 15°C to 45°C. A high activity toward AG25 (1 g/l with relative decolorization values of 91.2% (3 h and 97.1% (18 h, as well as high activity to AR18 (1 g/l by 80.5% (3 h and 89.0% (18 h, was recorded. The engineered system exhibited a comparably high activity compared with those of separate dyes in a continuous three-round shake-flask decolorization of AG25/AR18 mixed dye (each 1 g/l. No significant decline in decolorization efficacy was noted during first two-rounds but reaction equilibriums were elongated, and the residual laccase activity eventually decreased to low levels. However, the decolorizing capacity of the system was easily retrieved

  6. A Root-Colonizing Pseudomonad Lessens Stress Responses in Wheat Imposed by CuO Nanoparticles

    Science.gov (United States)

    Wright, Melanie; Adams, Joshua; Yang, Kwang; McManus, Paul; Jacobson, Astrid; Gade, Aniket; McLean, Joan; Britt, David; Anderson, Anne

    2016-01-01

    Nanoparticle (NPs) containing essential metals are being considered in formulations of fertilizers to boost plant nutrition in soils with low metal bioavailability. This paper addresses whether colonization of wheat roots by the bacterium, Pseudomonas chlororaphis O6 (PcO6), protected roots from the reduced elongation caused by CuO NPs. There was a trend for slightly elongated roots when seedlings with roots colonized by PcO6 were grown with CuO NPs; the density of bacterial cells on the root surface was not altered by the NPs. Accumulations of reactive oxygen species in the plant root cells caused by CuO NPs were little affected by root colonization. However, bacterial colonization did reduce the extent of expression of an array of genes associated with plant responses to stress induced by root exposure to CuO NPs. PcO6 colonization also reduced the levels of two important chelators of Cu ions, citric and malic acids, in the rhizosphere solution; presumably because these acids were used as nutrients for bacterial growth. There was a trend for lower levels of soluble Cu in the rhizosphere solution and reduced Cu loads in the true leaves with PcO6 colonization. These studies indicate that root colonization by bacterial cells modulates plant responses to contact with CuO NPs. PMID:27776146

  7. A Root-Colonizing Pseudomonad Lessens Stress Responses in Wheat Imposed by CuO Nanoparticles.

    Directory of Open Access Journals (Sweden)

    Melanie Wright

    Full Text Available Nanoparticle (NPs containing essential metals are being considered in formulations of fertilizers to boost plant nutrition in soils with low metal bioavailability. This paper addresses whether colonization of wheat roots by the bacterium, Pseudomonas chlororaphis O6 (PcO6, protected roots from the reduced elongation caused by CuO NPs. There was a trend for slightly elongated roots when seedlings with roots colonized by PcO6 were grown with CuO NPs; the density of bacterial cells on the root surface was not altered by the NPs. Accumulations of reactive oxygen species in the plant root cells caused by CuO NPs were little affected by root colonization. However, bacterial colonization did reduce the extent of expression of an array of genes associated with plant responses to stress induced by root exposure to CuO NPs. PcO6 colonization also reduced the levels of two important chelators of Cu ions, citric and malic acids, in the rhizosphere solution; presumably because these acids were used as nutrients for bacterial growth. There was a trend for lower levels of soluble Cu in the rhizosphere solution and reduced Cu loads in the true leaves with PcO6 colonization. These studies indicate that root colonization by bacterial cells modulates plant responses to contact with CuO NPs.

  8. A CASE STUDY OF NONPOINT SOURCES BACTERIAL CONTRIBUTION TO RURAL SURFACE WATER

    Science.gov (United States)

    The presentation will address several bacterial issues affecting the Turkey Creek (TC) watershed, in north central Ok. Our results from seasonal stream Escherichia coli (E. coli) analysis, bacterial source tracking, and antibiotic resistance will be shared and discussed in relat...

  9. Modification of anti-bacterial surface properties of textile polymers by vacuum arc ion source implantation

    Energy Technology Data Exchange (ETDEWEB)

    Nikolaev, A.G., E-mail: nik@opee.hcei.tsc.ru [High Current Electronics Institute, Siberian Branch of the Russian Academy of Sciences, Tomsk 634055 (Russian Federation); Yushkov, G.Yu.; Oks, E.M. [High Current Electronics Institute, Siberian Branch of the Russian Academy of Sciences, Tomsk 634055 (Russian Federation); Oztarhan, A. [Izmir University, Izmir 35140 (Turkey); Akpek, A.; Hames-Kocabas, E.; Urkac, E.S. [Bioengineering Department, Ege University, Bornova 35100, Izmir (Turkey); Brown, I.G. [Lawrence Berkeley National Laboratory, Berkeley, CA 94708 (United States)

    2014-08-15

    Highlights: • Ion implantation. • Anti-bacterial properties. • Textile polymer. • Vacuum arc ion source. - Abstract: Ion implantation provides an important technology for the modification of material surface properties. The vacuum arc ion source is a unique instrument for the generation of intense beams of metal ions as well as gaseous ions, including mixed metal–gas beams with controllable metal:gas ion ratio. Here we describe our exploratory work on the application of vacuum arc ion source-generated ion beams for ion implantation into polymer textile materials for modification of their biological cell compatibility surface properties. We have investigated two specific aspects of cell compatibility: (i) enhancement of the antibacterial characteristics (we chose to use Staphylococcus aureus bacteria) of ion implanted polymer textile fabric, and (ii) the “inverse” concern of enhancement of neural cell growth rate (we chose Rat B-35 neuroblastoma cells) on ion implanted polymer textile. The results of both investigations were positive, with implantation-generated antibacterial efficiency factor up to about 90%, fully comparable to alternative conventional (non-implantation) approaches and with some potentially important advantages over the conventional approach; and with enhancement of neural cell growth rate of up to a factor of 3.5 when grown on suitably implanted polymer textile material.

  10. In vivo targeting of surface-modified liposomes to metastatically growing colon carcinoma cells and sinusoidal endothelial cells in the rat liver.

    NARCIS (Netherlands)

    Scherphof, GL; Kamps, JAAM; Koning, GA

    1997-01-01

    We prepared immunoliposomes by covalent coupling of a randomly thiolated monoclonal antibody against the rat colon adenocarcinoma cell line CC531 to MPB-PE on the outer surface of conventional as well as PEGylated liposomes of about 100-nm diameter. We attempted to target these immunoliposomes in

  11. Bacterial surface appendages strongly impact nanomechanical and electrokinetic properties of Escherichia coli cells subjected to osmotic stress.

    Directory of Open Access Journals (Sweden)

    Grégory Francius

    Full Text Available The physicochemical properties and dynamics of bacterial envelope, play a major role in bacterial activity. In this study, the morphological, nanomechanical and electrohydrodynamic properties of Escherichia coli K-12 mutant cells were thoroughly investigated as a function of bulk medium ionic strength using atomic force microscopy (AFM and electrokinetics (electrophoresis. Bacteria were differing according to genetic alterations controlling the production of different surface appendages (short and rigid Ag43 adhesins, longer and more flexible type 1 fimbriae and F pilus. From the analysis of the spatially resolved force curves, it is shown that cells elasticity and turgor pressure are not only depending on bulk salt concentration but also on the presence/absence and nature of surface appendage. In 1 mM KNO(3, cells without appendages or cells surrounded by Ag43 exhibit large Young moduli and turgor pressures (∼700-900 kPa and ∼100-300 kPa respectively. Under similar ionic strength condition, a dramatic ∼50% to ∼70% decrease of these nanomechanical parameters was evidenced for cells with appendages. Qualitatively, such dependence of nanomechanical behavior on surface organization remains when increasing medium salt content to 100 mM, even though, quantitatively, differences are marked to a much smaller extent. Additionally, for a given surface appendage, the magnitude of the nanomechanical parameters decreases significantly when increasing bulk salt concentration. This effect is ascribed to a bacterial exoosmotic water loss resulting in a combined contraction of bacterial cytoplasm together with an electrostatically-driven shrinkage of the surface appendages. The former process is demonstrated upon AFM analysis, while the latter, inaccessible upon AFM imaging, is inferred from electrophoretic data interpreted according to advanced soft particle electrokinetic theory. Altogether, AFM and electrokinetic results clearly demonstrate the

  12. Potential Environmental Factors Affecting Oil-Degrading Bacterial Populations in Deep and Surface Waters of the Northern Gulf of Mexico.

    Science.gov (United States)

    Liu, Jiqing; Bacosa, Hernando P; Liu, Zhanfei

    2016-01-01

    Understanding bacterial community dynamics as a result of an oil spill is important for predicting the fate of oil released to the environment and developing bioremediation strategies in the Gulf of Mexico. In this study, we aimed to elucidate the roles of temperature, water chemistry (nutrients), and initial bacterial community in selecting oil degraders through a series of incubation experiments. Surface (2 m) and bottom (1537 m) waters, collected near the Deepwater Horizon site, were amended with 200 ppm light Louisiana sweet crude oil and bacterial inoculums from surface or bottom water, and incubated at 4 or 24°C for 50 days. Bacterial community and residual oil were analyzed by pyrosequencing and gas chromatography-mass spectrometry (GC-MS), respectively. The results showed that temperature played a key role in selecting oil-degrading bacteria. Incubation at 4°C favored the development of Cycloclasticus, Pseudoalteromonas , Sulfitobacter , and Reinekea , while 24°C incubations enhanced Oleibacter, Thalassobius, Phaeobacter, and Roseobacter. Water chemistry and the initial community also had potential roles in the development of hydrocarbon-degrading bacterial communities. Pseudoalteromonas , Oleibacter , and Winogradskyella developed well in the nutrient-enriched bottom water, while Reinekea and Thalassobius were favored by low-nutrient surface water. We revealed that the combination of 4°C, crude oil and bottom inoculum was a key factor for the growth of Cycloclasticus , while the combination of surface inoculum and bottom water chemistry was important for the growth of Pseudoalteromonas . Moreover, regardless of the source of inoculum, bottom water at 24°C was a favorable condition for Oleibacter. Redundancy analysis further showed that temperature and initial community explained 57 and 19% of the variation observed, while oil and water chemistry contributed 14 and 10%, respectively. Overall, this study revealed the relative roles of temperature, water

  13. Colonization of the Tongue Surface in Japanese Independent Elders: A Preliminary Study

    Directory of Open Access Journals (Sweden)

    Tomohisa Ohno

    2017-09-01

    Full Text Available Oral care is important to decrease oral bacteria, especially in the dependent elders. There have been some reports on oral microflora in the dependent elders. However, investigations involving healthy independent elders are limited. The purpose of this study was to obtain more information on the microflora in Japanese independent elders. One hundred Japanese independent elders aged 65 years or older participated in this study. Eighty-one independent elders (male: 44, female: 37, mean age: 72.7 ± 5.8 participated in this study. Their mean Barthel Index was 99.1 ± 3.1, and mean score of MMSE was 28.0 ± 2.3. The tongue bacterial flora was examinved to identify microorganisms by the culture method. The predominant aerobic organisms were Streptococcus spp. (detection rate: 100%, Neisseria spp. (96%, and Corynebacterium spp. (56%. Candida spp. was also isolated (32%. In this study, the oral microflora of the tongue in Japanese independent elders was clarified. The results of this investigation may contribute to research on oral bacteria in elder persons in the future.

  14. Surface-modified nanoparticles as a new, versatile, and mechanically robust nonadhesive coating : Suppression of protein adsorption and bacterial adhesion

    NARCIS (Netherlands)

    Holmes, P. F.; Currie, E. P. K.; Thies, J. C.; van der Mei, H. C.; Busscher, H. J.; Norde, W.

    2009-01-01

    The synthesis of surface-modified silica nanoparticles, chemically grafted with acrylate and poly(ethylene glycol) (PEG) groups, and the ability of the resulting crosslinked coatings to inhibit protein adsorption and bacterial adhesion are explored. Water contact angles, nanoindentation, and atomic

  15. Bacterial microflora isolated from the bark surface of poplars growing in areas where air pollution is very high

    Directory of Open Access Journals (Sweden)

    Krystyna Przybył

    2015-01-01

    Full Text Available In the autumn of 1976 bacteria of the genera Bacillus, Pseudomonas, Flavobacterium, Erwinia and Cellulomonas were isolated from the bark surface of poplars growing in protective belts around several industrial plants. It was found that the qualitative and quantitative composition of the surface bacterial microflora changes in dependence on the degree of resistance of the poplars to the action of the dust emitted by the industrial establishment and containing high amounts of heavy metals.

  16. Induction of specific immunoglobulin A in the small intestine, colon-rectum, and vagina measured by a new method for collection of secretions from local mucosal surfaces.

    OpenAIRE

    Haneberg, B; Kendall, D; Amerongen, H M; Apter, F M; Kraehenbuhl, J P; Neutra, M R

    1994-01-01

    In order study patterns of local antibody responses following mucosal immunization of mice via different routes, a method for collection of secretions directly from mucosal surfaces was developed. Mice were immunized on days 0, 10, 17, and 24 by administration of cholera toxin into the oral cavity, stomach, colon-rectum, or vagina. At sacrifice on day 32, absorbent wicks were placed in the oral cavity and, via an applicator tube, into the vagina and distal colon-rectum and along the entire sm...

  17. Induction of specific immunoglobulin A in the small intestine, colon-rectum, and vagina measured by a new method for collection of secretions from local mucosal surfaces.

    Science.gov (United States)

    Haneberg, B; Kendall, D; Amerongen, H M; Apter, F M; Kraehenbuhl, J P; Neutra, M R

    1994-01-01

    In order study patterns of local antibody responses following mucosal immunization of mice via different routes, a method for collection of secretions directly from mucosal surfaces was developed. Mice were immunized on days 0, 10, 17, and 24 by administration of cholera toxin into the oral cavity, stomach, colon-rectum, or vagina. At sacrifice on day 32, absorbent wicks were placed in the oral cavity and, via an applicator tube, into the vagina and distal colon-rectum and along the entire small intestine after flushing of luminal contents. Protein was quantitatively extracted from wicks, and specific anti-cholera toxin immunoglobulin A (IgA) and IgG were measured by enzyme-linked immunosorbent assay. Concentrations of specific IgA in secretions at various mucosal sites were dramatically influenced by the route of immunization. Oral immunization effectively induced IgA in saliva, and the intragastric route was optimal for induction of IgA in the small intestine. High levels of specific IgA appeared on the colonic-rectal mucosal surface only after rectal delivery of antigen. Oral, gastric, and rectal immunizations also produced distant responses in the vagina. Following vaginal immunization, however, neither local nor distant IgA responses were detected. These results suggest that vaccines intended for protection of colonic-rectal and vaginal mucosal surfaces might best be administered by the rectal route.

  18. Modulation of Candida albicans virulence by bacterial biofilms on titanium surfaces.

    Science.gov (United States)

    Cavalcanti, Yuri Wanderley; Wilson, Melanie; Lewis, Michael; Del-Bel-Cury, Altair Antoninha; da Silva, Wander José; Williams, David W

    2016-01-01

    Whilst Candida albicans occurs in peri-implant biofilms, its role in peri-implantitis remains unclear. This study therefore examined the virulence of C. albicans in mixed-species biofilms on titanium surfaces. Biofilms of C. albicans (Ca), C. albicans with streptococci (Streptococcus sanguinis, S. mutans) (Ca-Ss-Sm) and those incorporating Porphyromonas gingivalis (Ca-Pg and Ca-Ss-Sm-Pg) were developed. Expression of C. albicans genes associated with adhesion (ALS1, ALS3, HWP1) and hydrolytic enzymes (SAP2, SAP4, SAP6, PLD1) was measured and hyphal production by C. albicans quantified. Compared with Ca biofilms, significant (pbiofilms containing streptococci (Ca-Ss-Sm). In Ca-Pg biofilms, down-regulation of HWP1 and SAP4 expression, with reduced hyphal production occurred. Ca-Ss-Sm-Pg biofilms had increased hyphal proportions and up-regulation of ALS3, SAP2 and SAP6. In conclusion, C. albicans expressed virulence factors in biofilms that could contribute to peri-implantitis, but this was dependent on associated bacterial species.

  19. Temporal variation of coastal surface sediment bacterial communities along an environmental pollution gradient.

    Science.gov (United States)

    Thiyagarajan, V; Tsoi, M M Y; Zhang, W; Qian, P Y

    2010-07-01

    Terminal restriction fragment length polymorphism analysis (T-RFLP) was used to track the changes of bacterial community compositions (BCC) in coastal surface sediments along an environmental pollution gradient between 2004 and 2006. BCC in the chronically contaminated sites showed the largest deviation from those in the adjacent sites. Surprisingly, BCC at two contrasting environments (oceanic vs. river-influenced) were more similar. Unexpectedly, the BCC did not recover (when compared to oceanic control site) even after 5 years of pollution abatement initiatives in Victoria Harbour, Hong Kong. On the other hand, disposal of treated sewage for 5 years in one of the sites did not significantly affect the BCC. A striking seasonal variation in the BCC was observed at only the polluted sites. Although factors other than pollution gradients may explain the observed BCC patterns, the information presented here can be useful in predicting long-term effects of pollution on BCC. Furthermore, this study suggests that BCC analysis using T-RFLP is a faster, reliable and easier approach to monitor microbenthic community response to environmental pollution gradient in coastal sediments. 2010 Elsevier Ltd. All rights reserved.

  20. Mucin dynamics in intestinal bacterial infection.

    Directory of Open Access Journals (Sweden)

    Sara K Lindén

    Full Text Available Bacterial gastroenteritis causes morbidity and mortality in humans worldwide. Murine Citrobacter rodentium infection is a model for gastroenteritis caused by the human pathogens enteropathogenic Escherichia coli and enterohaemorrhagic E. coli. Mucin glycoproteins are the main component of the first barrier that bacteria encounter in the intestinal tract.Using Immunohistochemistry, we investigated intestinal expression of mucins (Alcian blue/PAS, Muc1, Muc2, Muc4, Muc5AC, Muc13 and Muc3/17 in healthy and C. rodentium infected mice. The majority of the C. rodentium infected mice developed systemic infection and colitis in the mid and distal colon by day 12. C. rodentium bound to the major secreted mucin, Muc2, in vitro, and high numbers of bacteria were found in secreted MUC2 in infected animals in vivo, indicating that mucins may limit bacterial access to the epithelial surface. In the small intestine, caecum and proximal colon, the mucin expression was similar in infected and non-infected animals. In the distal colonic epithelium, all secreted and cell surface mucins decreased with the exception of the Muc1 cell surface mucin which increased after infection (p<0.05. Similarly, during human infection Salmonella St Paul, Campylobacter jejuni and Clostridium difficile induced MUC1 in the colon.Major changes in both the cell-surface and secreted mucins occur in response to intestinal infection.

  1. Amide side chain amphiphilic polymers disrupt surface established bacterial bio-films and protect mice from chronic Acinetobacter baumannii infection.

    Science.gov (United States)

    Uppu, Divakara S S M; Samaddar, Sandip; Ghosh, Chandradhish; Paramanandham, Krishnamoorthy; Shome, Bibek R; Haldar, Jayanta

    2016-01-01

    Bacterial biofilms represent the root-cause of chronic or persistent infections in humans. Gram-negative bacterial infections due to nosocomial and opportunistic pathogens such as Acinetobacter baumannii are more difficult to treat because of their inherent and rapidly acquiring resistance to antibiotics. Due to biofilm formation, A. baumannii has been noted for its apparent ability to survive on artificial surfaces for an extended period of time, therefore allowing it to persist in the hospital environment. Here we report, maleic anhydride based novel cationic polymers appended with amide side chains that disrupt surface established multi-drug resistant A. baumannii biofilms. More importantly, these polymers significantly (p polymers also show potent antibacterial efficacy against methicillin resistant Staphylococcus aureus (MRSA), vancomycin resistant Enterococci (VRE) and multi-drug resistant clinical isolates of A. baumannii with minimal toxicity to mammalian cells. We observe that optimal hydrophobicity dependent on the side chain chemical structure of these polymers dictate the selective toxicity to bacteria. Polymers interact with the bacterial cell membranes by causing membrane depolarization, permeabilization and energy depletion. Bacteria develop rapid resistance to erythromycin and colistin whereas no detectable development of resistance occurs against these polymers even after several passages. These results suggest the potential use of these polymeric biomaterials in disinfecting biomedical device surfaces after the infection has become established and also for the topical treatment of chronic bacterial infections. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Bacterial translocation in rats nonfunctioning diverted distal colon Translocação bacteriana no coto colônico distal desfuncionalizado de ratos

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    Francisco Edilson Leite Pinto Júnior

    2007-06-01

    Full Text Available PURPOSE: To investigate whether the alterations of the diverted colon segment mucosa, evidenced in fecal colitis, would be able to alter Bacterial Translocation (BT. METHODS: Sixty-two Wistar male rats ranging from 220 to 320 grams of weight, were divided in two groups: A (Colostomy and B (Control, with 31 animals each one. In group A, all animals underwent end colostomy, one stoma, in ascending colon; and in the 70th POD was injected in five rats, by rectal route diverted segment - 2ml of a 0.9% saline solution in animals (A1 subgroup; in eight it was inoculated, by rectal route, 2ml of a solution containing Escherichia coli ATCC 25922 (American Type Culture Collection, in a concentration of 10(8 Colony Forming Unit for milliliters (CFU/ml - A2 Subgroup; in ten animals the same solution of E. coli was inoculated, in a concentration of 10(11 CFU/ml (A3 Subgroup; and in eight it was collected part of the mucus found in the diverted distal colonic segment for neutral sugars and total proteins dosage (A4 subgroup. The animals from the group B underwent the same procedures of group A, but with differences in the colostomy confection. In rats from subgroups A1, A2, A3, B1, B2, and B3 2ml of blood were aspirated from the heart, and fragments from mesenteric lymphatic nodule, liver, spleen, lung and kidney taken for microbiological analysis, after their death. This analysis consisted of evidencing the presence of E. coli ATCC 25922 CFU. Mann-Whitney and ANOVA Tests were applied as analytic techniques for association of variables. RESULTS: The occurrence of BT was evidenced only in those animals in which inoculated concentration of E. coli ATCC 25922, reached levels of 10(11CFU/ml, i.e. in Subgroups A3 and B3, although, being significantly greater (80% in those animals without colostomy (subgroup B3 when compared to the ones with colostomy (20% from the subgroup A3 (P OBJETIVO: Investigar se as alterações do cólon desfuncionalizado, evidenciadas na

  3. Mechanism of cell integration on biomaterial implant surfaces in the presence of bacterial contamination

    NARCIS (Netherlands)

    Yue, Chongxia; van der Mei, Henny C.; Kuijer, Roel; Busscher, Henk J.; Rochford, Edward T. J.

    2015-01-01

    Bacterial contamination during biomaterial implantation is often unavoidable, yielding a combat between cells and bacteria. Here we aim to determine the modulatory function of bacterial components on stem-cell, fibroblast, and osteoblast adhesion to a titanium alloy, including the role of

  4. Characterizing bacterial communities in tilapia pond surface sediment and their responses to pond differences and temporal variations.

    Science.gov (United States)

    Fan, Limin; Barry, Kamira; Hu, Gengdong; Meng, Shunlong; Song, Chao; Qiu, Liping; Zheng, Yao; Wu, Wei; Qu, Jianhong; Chen, Jiazhang; Xu, Pao

    2017-01-01

    Bacterial community compositions in the surface sediment of tilapia ponds and their responses to pond characteristics or seasonal variations were investigated. For that, three ponds with different stocking densities were selected to collect the samples. And the method of Illumina high-throughput sequencing was used to amplify the bacterial 16S rRNA genes. A total of 662, 876 valid reads and 5649 operational taxonomic units were obtained. Further analysis showed that the dominant phyla in all three ponds were Proteobacteria, Bacteroidetes, Chloroflexi, and Acidobacteria. The phyla Planctomycetes, Firmicutes, Chlorobi, and Spirochaetae were also relatively abundant. Among the eight phyla, the abundances of only Proteobacteria, Bacteroidetes, Firmicutes, and Spirochaetae were affected by seasonal variations, while seven of these (with the exception of Acidobacteria) were affected by pond differences. A comprehensive analysis of the richness and diversity of the bacterial 16S rRNA gene, and of the similarity in bacterial community composition in sediment also showed that the communities in tilapia pond sediment were shaped more by pond differences than by seasonal variations. Linear discriminant analysis further indicated that the influences of pond characteristics on sediment bacterial communities might be related to feed coefficients and stocking densities of genetically improved farmed tilapia (GIFT).

  5. Atomic Layer Deposition of a Silver Nanolayer on Advanced Titanium Orthopedic Implants Inhibits Bacterial Colonization and Supports Vascularized de Novo Bone Ingrowth.

    Science.gov (United States)

    Devlin-Mullin, Aine; Todd, Naomi M; Golrokhi, Zahra; Geng, Hua; Konerding, Moritz A; Ternan, Nigel G; Hunt, John A; Potter, Richard J; Sutcliffe, Chris; Jones, Eric; Lee, Peter D; Mitchell, Christopher A

    2017-06-01

    Joint replacement surgery is associated with significant morbidity and mortality following infection with either methicillin-resistant Staphylococcus aureus (MRSA) or Staphylococcus epidermidis. These organisms have strong biofilm-forming capability in deep wounds and on prosthetic surfaces, with 10 3 -10 4 microbes resulting in clinically significant infections. To inhibit biofilm formation, we developed 3D titanium structures using selective laser melting and then coated them with a silver nanolayer using atomic layer deposition. On bare titanium scaffolds, S. epidermidis growth was slow but on silver-coated implants there were significant further reductions in both bacterial recovery (p titanium scaffolds and not further affected by silver coating. Ultrastructural examination and viability assays using either human bone or endothelial cells, demonstrated strong adherence and growth on titanium-only or silver-coated implants. Histological, X-ray computed microtomographic, and ultrastructural analyses revealed that silver-coated titanium scaffolds implanted into 2.5 mm defects in rat tibia promoted robust vascularization and conspicuous bone ingrowth. We conclude that nanolayer silver of titanium implants significantly reduces pathogenic biofilm formation in vitro, facilitates vascularization and osseointegration in vivo making this a promising technique for clinical orthopedic applications. © 2017 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Effect of two different polishing systems on fluoride release, surface roughness and bacterial adhesion of newly developed restorative materials.

    Science.gov (United States)

    Bayrak, Gokcen Deniz; Sandalli, Nuket; Selvi-Kuvvetli, Senem; Topcuoglu, Nursen; Kulekci, Guven

    2017-11-12

    To evaluate the effects of two different polishing systems on fluoride release, surface roughness and bacterial adhesion of five restorative materials MATERIALS AND METHODS: The study groups were comprised of five different restorative materials, Beautifil II (B); GCP Glass Fill (G); Amalgomer CR (A); Dyract XP (D); Fuji IX GP (F) and 21 specimens were prepared from each material. Each group was divided into three subgroups according to the polishing system: Mylar (control) (C), Sof-lex (S), and Enhance-Pogo (EP). The amount of fluoride release was measured using a fluoride ion-selective electrode and surface roughness was investigated with a profilometer. Bacterial adhesion on the materials was evaluated by optical density readouts for S.mutans on a spectrophotometer. The highest amount of fluoride was released from specimens in the S subgroup of group G during all measurement days. Surface roughness values were significantly lower in subgroup C than the other polishing systems in all study groups except group G (P restorative materials especially in glass ionomer-based materials. This article stated that polishing promoted a significant increase of fluoride release on restorative materials especially in glass ionomer-based materials. Further, proper polishing systems must be chosen according to the structure and composition of materials to provide the best clinical benefits in terms of fluoride release, surface roughness and bacterial adhesion. © 2017 Wiley Periodicals, Inc.

  7. Bacterial Adhesion & Blocking Bacterial Adhesion

    DEFF Research Database (Denmark)

    Vejborg, Rebecca Munk

    2008-01-01

    reduce or delay bacterial biofilm formation of a range of urinary tract infectious E.coli and Klebsiella isolates. Several other proteinaceous coatings were also found to display anti-adhesive properties, possibly providing a measure for controlling the colonization of implant materials. Several other...... components. These substances may both mediate and stabilize the bacterial biofilm. Finally, several adhesive structures were examined, and a novel physiological biofilm phenotype in E.coli biofilms was characterized, namely cell chain formation. The autotransporter protein, antigen 43, was implicated...

  8. Rapid label-free identification of mixed bacterial infections by surface plasmon resonance

    Directory of Open Access Journals (Sweden)

    Fu Weiling

    2011-06-01

    Full Text Available Abstract Background Early detection of mixed aerobic-anaerobic infection has been a challenge in clinical practice due to the phenotypic changes in complex environments. Surface plasmon resonance (SPR biosensor is widely used to detect DNA-DNA interaction and offers a sensitive and label-free approach in DNA research. Methods In this study, we developed a single-stranded DNA (ssDNA amplification technique and modified the traditional SPR detection system for rapid and simultaneous detection of mixed infections of four pathogenic microorganisms (Pseudomonas aeruginosa, Staphylococcus aureus, Clostridium tetani and Clostridium perfringens. Results We constructed the circulation detection well to increase the sensitivity and the tandem probe arrays to reduce the non-specific hybridization. The use of 16S rDNA universal primers ensured the amplification of four target nucleic acid sequences simultaneously, and further electrophoresis and sequencing confirmed the high efficiency of this amplification method. No significant signals were detected during the single-base mismatch or non-specific probe hybridization (P 2 values of >0.99. The lowest detection limits were 0.03 nM for P. aeruginosa, 0.02 nM for S. aureus, 0.01 nM for C. tetani and 0.02 nM for C. perfringens. The SPR biosensor had the same detection rate as the traditional culture method (P Conclusions Our method can rapidly and accurately identify the mixed aerobic-anaerobic infection, providing a reliable alternative to bacterial culture for rapid bacteria detection.

  9. Role of bacterial surface structures on the interaction of Klebsiella pneumoniae with phagocytes.

    Directory of Open Access Journals (Sweden)

    Catalina March

    Full Text Available Phagocytosis is a key process of the immune system. The human pathogen Klebsiella pneumoniae is a well known example of a pathogen highly resistant to phagocytosis. A wealth of evidence demonstrates that the capsule polysaccharide (CPS plays a crucial role in resistance to phagocytosis. The amoeba Dictyostelium discoideum shares with mammalian macrophages the ability to phagocytose and kill bacteria. The fact that K. pneumoniae is ubiquitous in nature and, therefore, should avoid predation by amoebae, poses the question whether K. pneumoniae employs similar means to counteract amoebae and mammalian phagocytes. Here we developed an assay to evaluate K. pneumoniae-D. discoideum interaction. The richness of the growth medium affected the threshold at which the cps mutant was permissive for Dictyostelium and only at lower nutrient concentrations the cps mutant was susceptible to predation by amoebae. Given the critical role of bacterial surface elements on host-pathogen interactions, we explored the possible contribution of the lipopolysaccharide (LPS and outer membrane proteins (OMPs to combat phagoyctosis by D. discoideum. We uncover that, in addition to the CPS, the LPS O-polysaccharide and the first core sugar participate in Klebsiella resistance to predation by D. discoideum. K. pneumoniae LPS lipid A decorations are also necessary to avoid predation by amoebae although PagP-dependent palmitoylation plays a more important role than the lipid A modification with aminoarabinose. Mutants lacking OMPs OmpA or OmpK36 were also permissive for D. discoideium growth. Except the LPS O-polysaccharide mutants, all mutants were more susceptible to phagocytosis by mouse alveolar macrophages. Finally, we found a correlation between virulence, using the pneumonia mouse model, and resistance to phagocytosis. Altogether, this work reveals novel K. pneumoniae determinants involved in resistance to phagocytosis and supports the notion that Dictyostelium amoebae

  10. Immortalization of Fetal Bovine Colon Epithelial Cells by Expression of Human Cyclin D1, Mutant Cyclin Dependent Kinase 4, and Telomerase Reverse Transcriptase: An In Vitro Model for Bacterial Infection.

    Directory of Open Access Journals (Sweden)

    Kengo Kuroda

    Full Text Available Cattle are the economically important animals in human society. They are essential for the production of livestock products such as milk and meats. The production efficiency of livestock products is negatively impacted by infection with zoonotic pathogens. To prevent and control infectious diseases, it is important to understand the interaction between cattle tissue and pathogenic bacteria. In this study, we established an in vitro infection model of an immortalized bovine colon-derived epithelial cell line by transducing the cells with lentiviral vectors containing genes encoding cell cycle regulators cyclin D1, mutant cyclin dependent kinase 4 (CDK4, and human telomerase reverse transcriptase (TERT. The established cell line showed continuous cell proliferation, expression of epithelial markers, and an intact karyotype, indicating that the cells maintained their original nature as colon-derived epithelium. Furthermore, we exposed the established cell line to two strains of Salmonella enterica and EHEC. Interestingly, S. Typhimurium showed higher affinity for the established cell line and invaded the cytoplasm than S. Enteritidis. Quantitative RT-PCR revealed that gene expression of Toll-like receptor 1 (TLR1, TLR 2 and TLR 3, whereas TLR 4, 5 and 6 were not detectable in established cells. Our established immortalized colon-derived epithelial cell should be a useful tool for studies evaluating the molecular mechanisms underlying bacterial infection.

  11. Immortalization of Fetal Bovine Colon Epithelial Cells by Expression of Human Cyclin D1, Mutant Cyclin Dependent Kinase 4, and Telomerase Reverse Transcriptase: An In Vitro Model for Bacterial Infection.

    Science.gov (United States)

    Kuroda, Kengo; Kiyono, Tohru; Isogai, Emiko; Masuda, Mizuki; Narita, Moe; Okuno, Katsuya; Koyanagi, Yukako; Fukuda, Tomokazu

    2015-01-01

    Cattle are the economically important animals in human society. They are essential for the production of livestock products such as milk and meats. The production efficiency of livestock products is negatively impacted by infection with zoonotic pathogens. To prevent and control infectious diseases, it is important to understand the interaction between cattle tissue and pathogenic bacteria. In this study, we established an in vitro infection model of an immortalized bovine colon-derived epithelial cell line by transducing the cells with lentiviral vectors containing genes encoding cell cycle regulators cyclin D1, mutant cyclin dependent kinase 4 (CDK4), and human telomerase reverse transcriptase (TERT). The established cell line showed continuous cell proliferation, expression of epithelial markers, and an intact karyotype, indicating that the cells maintained their original nature as colon-derived epithelium. Furthermore, we exposed the established cell line to two strains of Salmonella enterica and EHEC. Interestingly, S. Typhimurium showed higher affinity for the established cell line and invaded the cytoplasm than S. Enteritidis. Quantitative RT-PCR revealed that gene expression of Toll-like receptor 1 (TLR1), TLR 2 and TLR 3, whereas TLR 4, 5 and 6 were not detectable in established cells. Our established immortalized colon-derived epithelial cell should be a useful tool for studies evaluating the molecular mechanisms underlying bacterial infection.

  12. Microbiological spectrum of the intraperitoneal surface after elective right-sided colon cancer: are there differences in the peritoneal contamination after performing a stapled or a handsewn anastomosis?

    Science.gov (United States)

    Ruiz-Tovar, Jaime; Santos, Jair; Arroyo, Antonio; Llavero, Carolina; López, Alberto; Frangi, Andres; Armañanzas, Laura; Alcaide, Maria Jose; Candela, Fernando; Calpena, Rafael

    2012-11-01

    Although colonic surgery is performed with strict aseptic measures, some contamination is nearly impossible to avoid. In stapled anastomosis, the hole opened in the colon is minimum, just necessary for introducing the parts of the mechanical devices. In handsewn anastomosis, the colonic lumen is more exposed to the peritoneum, despite colonic occlusion with clamps while the suture is performed. A prospective, randomized study was performed between October 2009 and June 2011. Inclusion criteria were a diagnosis of right-sided colon cancer and having undergone an elective surgery with curative aims. The patients were divided into two groups: those patients undergoing a stapled ileocolonic anastomosis (group 1) and those undergoing a handsewn anastomosis (group 2). A microbiological sample was obtained from the peritoneal surface before opening the colon and after finishing the anastomosis in each group. Data were correlated with the wound infection and intra-abdominal infection rates. Eighty-four patients were included in the study: 42 patients in each group. There were two intra-abdominal abscesses (5 %) in each group (NS). Wound infection rate was 10 % in group 1 and 7 % in group 2 (NS). Mean operative time was 98.8 min in the stapled group and 105.2 min in the handsewn one (P = 0.013). Positive cultures were obtained in 79 % of the cases after stapled anastomosis and 73 % after handsewn ones (NS). Peritoneal contamination appears in over 70 % of cases after ileocolonic anastomosis. Significant differences in peritoneal contamination, wound infection, and intra-abdominal abscess between stapled and handsewn anastomoses could not be demonstrated.

  13. Bacterial adhesion to orthopaedic implant materials and a novel oxygen plasma modified PEEK surface

    NARCIS (Netherlands)

    Rochford, E. T. J.; Poulsson, A. H. C.; Salavarrieta Varela, J.; Lezuo, P.; Richards, R. G.; Moriarty, T. F.

    2014-01-01

    Despite extensive use of polyetheretherketone (PEEK) in biomedical applications, information about bacterial adhesion to this biomaterial is limited. This study investigated Staphylococcus aureus and Staphylococcus epidermidis adhesion to injection moulded and machined PEEK OPTIMA (R) using a

  14. A Polymethyl Methacrylate-Based Acrylic Dental Resin Surface Bound with a Photoreactive Polymer Inhibits Accumulation of Bacterial Plaque.

    Science.gov (United States)

    Fukunishi, Miya; Inoue, Yuuki; Morisaki, Hirobumi; Kuwata, Hirotaka; Ishihara, Kazuhiko; Baba, Kazuyoshi

    The aim of this study was to examine the ability of a poly(2-methacryloyloxyethyl phosphorylcholine-co-n-butylmethacrylate-co-2-methacryloyloxyethyloxy-p-azidobenzoate) (PMBPAz) coating on polymethyl methacrylate (PMMA)-based dental resin to inhibit bacterial plaque formation, as well as the polymer's durability against water soaking and chemical exposure. Successful application of PMBPAz on PMMA surfaces was confirmed by x-ray photoelectron spectroscopy (XPS) and measuring the static air contact angle in water. The anti-adhesive effects to bacterial plaque were evaluated using Streptococcus mutans biofilm formation assay. The mechanical and chemical durabilities of the PMBPAz coating on the PMMA surfaces were examined using soaking and immersion tests, respectively. XPS signals for phosphorus and nitrogen atoms and hydrophilic status on PMMA surfaces treated with PMBPAz were observed, indicating the presence of the polymer on the substrates. The treated PMMA surfaces showed significant inhibition of S mutans biofilm formation compared to untreated surfaces. The PMBPAz coating was preserved after water soaking and chemical exposure. In addition, water soaking did not decrease the ability of treated PMMA to inhibit biofilm formation compared to treated PMMA specimens not subjected to water soaking. This study suggests that PMBPAz coating may represent a useful modification to PMMA surfaces for inhibiting denture plaque accumulation.

  15. Proteome Analysis Identifies the Dpr Protein of Streptococcus mutans as an Important Factor in the Presence of Early Streptococcal Colonizers of Tooth Surfaces

    Science.gov (United States)

    Yoshida, Akihiro; Niki, Mamiko; Yamamoto, Yuji; Yasunaga, Ai; Ansai, Toshihiro

    2015-01-01

    Oral streptococci are primary colonizers of tooth surfaces and Streptococcus mutans is the principal causative agent of dental caries in humans. A number of proteins are involved in the formation of monospecies biofilms by S. mutans. This study analyzed the protein expression profiles of S. mutans biofilms formed in the presence or absence of S. gordonii, a pioneer colonizer of the tooth surface, by two-dimensional gel electrophoresis (2-DE). After identifying S. mutans proteins by Mass spectrometric analysis, their expression in the presence of S. gordonii was analyzed. S. mutans was inoculated with or without S. gordonii DL1. The two species were compartmentalized using 0.2-μl Anopore membranes. The biofilms on polystyrene plates were harvested, and the solubilized proteins were separated by 2-DE. When S. mutans biofilms were formed in the presence of S. gordonii, the peroxide resistance protein Dpr of the former showed 4.3-fold increased expression compared to biofilms that developed in the absence of the pioneer colonizer. In addition, we performed a competition assay using S. mutans antioxidant protein mutants together with S. gordonii and other initial colonizers. Growth of the dpr-knockout S. mutans mutant was significantly inhibited by S. gordonii, as well as by S. sanguinis. Furthermore, a cell viability assay revealed that the viability of the dpr-defective mutant was significantly attenuated compared to the wild-type strain when co-cultured with S. gordonii. Therefore, these results suggest that Dpr might be one of the essential proteins for S. mutans survival on teeth in the presence of early colonizing oral streptococci. PMID:25816242

  16. Bacterial cell-surface displaying of thermo-tolerant glutamate dehydrogenase and its application in L-glutamate assay.

    Science.gov (United States)

    Song, Jianxia; Liang, Bo; Han, Dongfei; Tang, Xiangjiang; Lang, Qiaolin; Feng, Ruirui; Han, Lihui; Liu, Aihua

    2015-03-01

    In this paper, glutamate dehydrogenase (Gldh) is reported to efficiently display on Escherichia coli cell surface by using N-terminal region of ice the nucleation protein as an anchoring motif. The presence of Gldh was confirmed by SDS-PAGE and enzyme activity assay. Gldh was detected mainly in the outer membrane fraction, suggesting that the Gldh was displayed on the bacterial cell surface. The optimal temperature and pH for the bacteria cell-surface displayed Gldh (bacteria-Gldh) were 70°C and 9.0, respectively. Additionally, the fusion protein retained almost 100% of its initial enzymatic activity after 1 month incubation at 4°C. Transition metal ions could inhibit the enzyme activity to different extents, while common anions had little adverse effect on enzyme activity. Importantly, the displayed Gldh is most specific to l-glutamate reported so far. The bacterial Gldh was enabled to catalyze oxidization of l-glutamate with NADP(+) as cofactor, and the resultant NADPH can be detected spectrometrically at 340nm. The bacterial-Gldh based l-glutamate assay was established, where the absorbance at 340nm increased linearly with the increasing l-glutamate concentration within the range of 10-400μM. Further, the proposed approach was successfully applied to measure l-glutamate in real samples. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. A Perfect Storm: Increased Colonization and Failure of Vaccination Leads to Severe Secondary Bacterial Infection in Influenza Virus-Infected Obese Mice

    Directory of Open Access Journals (Sweden)

    Erik A. Karlsson

    2017-09-01

    Full Text Available Obesity is a risk factor for developing severe disease following influenza virus infection; however, the comorbidity of obesity and secondary bacterial infection, a serious complication of influenza virus infections, is unknown. To fill this gap in knowledge, lean and obese C57BL/6 mice were infected with a nonlethal dose of influenza virus followed by a nonlethal dose of Streptococcus pneumoniae. Strikingly, not only did significantly enhanced death occur in obese coinfected mice compared to lean controls, but also high mortality was seen irrespective of influenza virus strain, bacterial strain, or timing of coinfection. This result was unexpected, given that most influenza virus strains, especially seasonal human A and B viruses, are nonlethal in this model. Both viral and bacterial titers were increased in the upper respiratory tract and lungs of obese animals as early as days 1 and 2 post-bacterial infection, leading to a significant decrease in lung function. This increased bacterial load correlated with extensive cellular damage and upregulation of platelet-activating factor receptor, a host receptor central to pneumococcal invasion. Importantly, while vaccination of obese mice against either influenza virus or pneumococcus failed to confer protection, antibiotic treatment was able to resolve secondary bacterial infection-associated mortality. Overall, secondary bacterial pneumonia could be a widespread, unaddressed public health problem in an increasingly obese population.

  18. The chemical composition of the pharmacologically active Thymus species, its antibacterial activity against Streptococcus mutans and the antiadherent effects of T. vulgaris on the bacterial colonization of the in situ pellicle.

    Science.gov (United States)

    Schött, Gesche; Liesegang, Stefanie; Gaunitz, Franziska; Gleß, Alexandra; Basche, Sabine; Hannig, Christian; Speer, Karl

    2017-09-01

    The pharmacological active genus Thymus L. comprises over 200 species. Besides its traditional pharmacological use, thyme may reduce the risk of caries disease, however, there is very little respective literature. The pharmacological effects can be attributed to the secondary plant metabolites. The composition of the essential oil and the polyphenols is important for the evaluation of the pharmacological activity. Nevertheless, there are no studies regarding a comparative analysis of the different pharmacological thyme species. In the present study, four different pharmacology Thymus species were cultivated under comparable conditions, and the volatile compounds as well as the polyphenols were characterized. In addition, the in vitro antibacterial activity against S. mutans, one of the primary cariogenic bacterial species, as well as of the essential oil and of the polyphenols were investigated. Furthermore, the bacterial viability and its effect on the initial bacterial adhesion under oral conditions were evaluated in situ for the essential oil and the polyphenols. By GC-MS, 69 volatile compounds, and by LC-DAD-MS/MS, 46 polyphenols could be identified. The comprehensive examination of the essential oils and the polyphenols revealed that the main compounds were equal. However, the yield of the essential oil and the polyphenol content differed clearly. The essential oils of the four investigated Thymus species exhibited an antibacterial activity against S. mutans in vitro, in contrast to the polyphenols of T. vulgaris. Rinsing with polyphenol-rich infusions reduced the initial bacterial colonization while the essential oil inhibited the bacterial growth on dental enamel in situ. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Chimeric FimH adhesin of type 1 fimbriae: a bacterial surface display system for heterologous sequences

    DEFF Research Database (Denmark)

    Pallesen, L; Poulsen, LK; Christiansen, Gunna

    1995-01-01

    of heterologous DNA segments encoding two reporter sequences. In the selected positions such insertions did not significantly alter the function of the FimH protein with regard to surface location and adhesive ability. The system seemed to be quite flexible, since chimeric versions of the FimH adhesin containing......The FimH adhesin of type 1 fimbriae has been tested as a display system for heterologous protein segments on the surface of Escherichia coli. This was carried out by introduction of restriction site handles (BglII sites) in two different positions in the fimH gene, followed by in-frame insertion...... as many as 56 foreign amino acids were transported to the bacterial surface as components of the fimbrial organelles. Furthermore, the foreign protein segments were recognized by insert-specific antibodies when expressed within chimeric proteins on the surface of the bacteria. The results from...

  20. A Bacterial Surface Display System Expressing Cleavable Capsid Proteins of Human Norovirus: A Novel System to Discover Candidate Receptors

    Directory of Open Access Journals (Sweden)

    Qian Xu

    2017-12-01

    Full Text Available Human noroviruses (HuNoVs are the dominant cause of food-borne outbreaks of acute gastroenteritis. However, fundamental researches on HuNoVs, such as identification of viral receptors have been limited by the currently immature system to culture HuNoVs and the lack of efficient small animal models. Previously, we demonstrated that the recombinant protruding domain (P domain of HuNoVs capsid proteins were successfully anchored on the surface of Escherichia coli BL21 cells after the bacteria were transformed with a plasmid expressing HuNoVs P protein fused with bacterial transmembrane anchor protein. The cell-surface-displayed P proteins could specifically recognize and bind to histo-blood group antigens (HBGAs, receptors of HuNoVs. In this study, an upgraded bacterial surface displayed system was developed as a new platform to discover candidate receptors of HuNoVs. A thrombin-susceptible “linker” sequence was added between the sequences of bacterial transmembrane anchor protein and P domain of HuNoV (GII.4 capsid protein in a plasmid that displays the functional P proteins on the surface of bacteria. In this new system, the surface-displayed HuNoV P proteins could be released by thrombin treatment. The released P proteins self-assembled into small particles, which were visualized by electron microscopy. The bacteria with the surface-displayed P proteins were incubated with pig stomach mucin which contained HBGAs. The bacteria-HuNoV P proteins-HBGAs complex could be collected by low speed centrifugation. The HuNoV P proteins-HBGAs complex was then separated from the recombinant bacterial surface by thrombin treatment. The released viral receptor was confirmed by using the monoclonal antibody against type A HBGA. It demonstrated that the new system was able to capture and easily isolate receptors of HuNoVs. This new strategy provides an alternative, easier approach for isolating unknown receptors/ligands of HuNoVs from different samples

  1. Pathogenic bacteria colonizing the airways in asymptomatic neonates stimulates topical inflammatory mediator release

    DEFF Research Database (Denmark)

    Følsgaard, Nilofar Vahman; Schjørring, Susanne; Chawes, Bo Lund Krogsgaard

    2013-01-01

    Rationale: Bacterial colonization of neonatal airways with the pathogenic bacterial species, Moraxella catarrhalis, Streptococcus pneumoniae, and Haemophilus influenzae, is associated with later development of childhood asthma. Objectives: To study a possible association between colonization with...

  2. Nasopharyngeal and Adenoid Colonization by Haemophilus influenzae and Haemophilus parainfluenzae in Children Undergoing Adenoidectomy and the Ability of Bacterial Isolates to Biofilm Production.

    Science.gov (United States)

    Kosikowska, Urszula; Korona-Głowniak, Izabela; Niedzielski, Artur; Malm, Anna

    2015-05-01

    Haemophili are pathogenic or opportunistic bacteria often colonizing the upper respiratory tract mucosa. The prevalence of Haemophilus influenzae (with serotypes distribution), and H. parainfluenzae in the nasopharynx and/or the adenoid core in children with recurrent pharyngotonsillitis undergoing adenoidectomy was assessed. Haemophili isolates were investigated for their ability to biofilm production.Nasopharyngeal swabs and the adenoid core were collected from 164 children who underwent adenoidectomy (2-5 years old). Bacteria were identified by the standard methods. Serotyping of H. influenzae was performed using polyclonal and monoclonal antisera. Biofilm formation was detected spectrophotometrically using 96-well microplates and 0.1% crystal violet.Ninety seven percent (159/164) children who underwent adenoidectomy were colonized by Haemophilus spp. The adenoid core was colonized in 99.4% (158/159) children, whereas the nasopharynx in 47.2% (75/159) children (P influenzae were identified, in 22.6% (36/159) children only (nonencapsulated) H. influenzae NTHi (nonencapsulated) isolates were present, whereas 7.5% (12/159) children were colonized by both types. 14.5% (23/159) children were colonized by untypeable (rough) H. influenzae. In 22% (35/159) children H. influenzae serotype d was isolated. Totally, 192 isolates of H. influenzae, 96 isolates of H. parainfluenzae and 14 isolates of other Haemophilus spp. were selected. In 20.1% (32/159) children 2 or 3 phenotypically different isolates of the same species (H. influenzae or H. parainfluenzae) or serotypes (H. influenzae) were identified in 1 child. 67.2% (129/192) isolates of H. influenzae, 56.3% (54/96) isolates of H. parainfluenzae and 85.7% (12/14) isolates of other Haemophilus spp. were positive for biofilm production. Statistically significant differences (P = 0.0029) among H. parainfluenzae biofilm producers and nonproducers in the adenoid core and the nasopharynx were detected.H. influenzae and H

  3. Surface topography of composite restorative materials following ultrasonic scaling and its Impact on bacterial plaque accumulation. An in-vitro SEM study

    Science.gov (United States)

    Hossam, A. Eid; Rafi, A. Togoo; Ahmed, A Saleh; Sumanth, Phani CR

    2013-01-01

    Background: This is an in vitro study to investigate the effects of ultrasonic scaling on the surface roughness and quantitative bacterial count on four different types of commonly used composite restorative materials for class V cavities. Materials & Methods: Nanofilled, hybrid, silorane and flowable composites were tested. Forty extracted teeth served as specimen and were divided into 4 groups of 10 specimens, with each group receiving a different treatment and were examined by a Field emission scanning electron microscope. Bacterial suspension was then added to the pellicle-coated specimens, and then bacterial adhesion was analyzed by using image analyzing program. Results: Flowable and silorane-based composites showed considerably smoother surfaces and lesser bacterial count in comparison to other types, proving that bacterial adhesion is directly proportional to surface roughness. Conclusion: The use of ultrasonic scalers affects the surfaces of composite restorative materials. Routine periodontal scaling should be carried out very carefully, and polishing of the scaled surfaces may overcome the alterations in roughness, thus preventing secondary caries, surface staining, plaque accumulation and subsequent periodontal inflammation. How to cite this article: Eid H A, Togoo R A, Saleh A A, Sumanth C R. Surface Topography of Composite Restorative Materials following Ultrasonic Scaling and its Impact on Bacterial Plaque Accumulation. An In-Vitro SEM Study. J Int Oral Health 2013; 5(3):13-19. PMID:24155597

  4. Rapid Identification of Bacterial Pathogens of Military Interest Using Surface-Enhanced Raman Spectroscopy

    Science.gov (United States)

    2014-06-11

    wound infections. Methods: A total of sixteen bacterial isolates including: six Acinetobacter baumannii , four Staphylococcus aureus, three... Acinetobacter baumannii -calcoaceticus complex, which remains a critical cause of infection. Additionally, there has been a dramatic increase of...manufacturer’s instructions. Lysozyme treatment was used for Acinetobacter baumannii prior to cell lysis, while lysostaphin and lysozyme were used for

  5. Colonic Diseases

    Science.gov (United States)

    ... Ulcerative colitis - ulcers of the colon and rectum Diverticulitis - inflammation or infection of pouches in the colon Irritable bowel syndrome - an uncomfortable condition causing abdominal cramping and other symptoms Treatment for colonic diseases varies greatly depending on the disease and its ...

  6. A Method for Quantification of Epithelium Colonization Capacity by Pathogenic Bacteria

    Directory of Open Access Journals (Sweden)

    Rune M. Pedersen

    2018-02-01

    Full Text Available Most bacterial infections initiate at the mucosal epithelium lining the gastrointestinal, respiratory, and urogenital tracts. At these sites, bacterial pathogens must adhere and increase in numbers to effectively breach the outer barrier and invade the host. If the bacterium succeeds in reaching the bloodstream, effective dissemination again requires that bacteria in the blood, reestablish contact to distant endothelium sites and form secondary site foci. The infectious potential of bacteria is therefore closely linked to their ability to adhere to, colonize, and invade epithelial and endothelial surfaces. Measurement of bacterial adhesion to epithelial cells is therefore standard procedure in studies of bacterial virulence. Traditionally, such measurements have been conducted with microtiter plate cell cultures to which bacteria are added, followed by washing procedures and final quantification of retained bacteria by agar plating. This approach is fast and straightforward, but yields only a rough estimate of the adhesive properties of the bacteria upon contact, and little information on the ability of the bacterium to colonize these surfaces under relevant physiological conditions. Here, we present a method in which epithelia/endothelia are simulated by flow chamber-grown human cell layers, and infection is induced by seeding of pathogenic bacteria on these surfaces under conditions that simulate the physiological microenvironment. Quantification of bacterial adhesion and colonization of the cell layers is then performed by in situ time-lapse fluorescence microscopy and automatic detection of bacterial surface coverage. The method is demonstrated in three different infection models, simulating Staphylococcus aureus endothelial infection and Escherichia coli intestinal- and uroepithelial infection. The approach yields valuable information on the fitness of the bacterium to successfully adhere to and colonize epithelial surfaces and can be used

  7. Crystal structure of bacterial cell-surface alginate-binding protein with an M75 peptidase motif.

    Science.gov (United States)

    Maruyama, Yukie; Ochiai, Akihito; Mikami, Bunzo; Hashimoto, Wataru; Murata, Kousaku

    2011-02-18

    A gram-negative Sphingomonas sp. A1 directly incorporates alginate polysaccharide into the cytoplasm via the cell-surface pit and ABC transporter. A cell-surface alginate-binding protein, Algp7, functions as a concentrator of the polysaccharide in the pit. Based on the primary structure and genetic organization in the bacterial genome, Algp7 was found to be homologous to an M75 peptidase motif-containing EfeO, a component of a ferrous ion transporter. Despite the presence of an M75 peptidase motif with high similarity, the Algp7 protein purified from recombinant Escherichia coli cells was inert on insulin B chain and N-benzoyl-Phe-Val-Arg-p-nitroanilide, both of which are substrates for a typical M75 peptidase, imelysin, from Pseudomonas aeruginosa. The X-ray crystallographic structure of Algp7 was determined at 2.10Å resolution by single-wavelength anomalous diffraction. Although a metal-binding motif, HxxE, conserved in zinc ion-dependent M75 peptidases is also found in Algp7, the crystal structure of Algp7 contains no metal even at the motif. The protein consists of two structurally similar up-and-down helical bundles as the basic scaffold. A deep cleft between the bundles is sufficiently large to accommodate macromolecules such as alginate polysaccharide. This is the first structural report on a bacterial cell-surface alginate-binding protein with an M75 peptidase motif. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. Crystal structure of bacterial cell-surface alginate-binding protein with an M75 peptidase motif

    International Nuclear Information System (INIS)

    Maruyama, Yukie; Ochiai, Akihito; Mikami, Bunzo; Hashimoto, Wataru; Murata, Kousaku

    2011-01-01

    Research highlights: → Bacterial alginate-binding Algp7 is similar to component EfeO of Fe 2+ transporter. → We determined the crystal structure of Algp7 with a metal-binding motif. → Algp7 consists of two helical bundles formed through duplication of a single bundle. → A deep cleft involved in alginate binding locates around the metal-binding site. → Algp7 may function as a Fe 2+ -chelated alginate-binding protein. -- Abstract: A gram-negative Sphingomonas sp. A1 directly incorporates alginate polysaccharide into the cytoplasm via the cell-surface pit and ABC transporter. A cell-surface alginate-binding protein, Algp7, functions as a concentrator of the polysaccharide in the pit. Based on the primary structure and genetic organization in the bacterial genome, Algp7 was found to be homologous to an M75 peptidase motif-containing EfeO, a component of a ferrous ion transporter. Despite the presence of an M75 peptidase motif with high similarity, the Algp7 protein purified from recombinant Escherichia coli cells was inert on insulin B chain and N-benzoyl-Phe-Val-Arg-p-nitroanilide, both of which are substrates for a typical M75 peptidase, imelysin, from Pseudomonas aeruginosa. The X-ray crystallographic structure of Algp7 was determined at 2.10 A resolution by single-wavelength anomalous diffraction. Although a metal-binding motif, HxxE, conserved in zinc ion-dependent M75 peptidases is also found in Algp7, the crystal structure of Algp7 contains no metal even at the motif. The protein consists of two structurally similar up-and-down helical bundles as the basic scaffold. A deep cleft between the bundles is sufficiently large to accommodate macromolecules such as alginate polysaccharide. This is the first structural report on a bacterial cell-surface alginate-binding protein with an M75 peptidase motif.

  9. Crystal structure of bacterial cell-surface alginate-binding protein with an M75 peptidase motif

    Energy Technology Data Exchange (ETDEWEB)

    Maruyama, Yukie; Ochiai, Akihito [Laboratory of Basic and Applied Molecular Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan); Mikami, Bunzo [Laboratory of Applied Structural Biology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan); Hashimoto, Wataru [Laboratory of Basic and Applied Molecular Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan); Murata, Kousaku, E-mail: kmurata@kais.kyoto-u.ac.jp [Laboratory of Basic and Applied Molecular Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan)

    2011-02-18

    Research highlights: {yields} Bacterial alginate-binding Algp7 is similar to component EfeO of Fe{sup 2+} transporter. {yields} We determined the crystal structure of Algp7 with a metal-binding motif. {yields} Algp7 consists of two helical bundles formed through duplication of a single bundle. {yields} A deep cleft involved in alginate binding locates around the metal-binding site. {yields} Algp7 may function as a Fe{sup 2+}-chelated alginate-binding protein. -- Abstract: A gram-negative Sphingomonas sp. A1 directly incorporates alginate polysaccharide into the cytoplasm via the cell-surface pit and ABC transporter. A cell-surface alginate-binding protein, Algp7, functions as a concentrator of the polysaccharide in the pit. Based on the primary structure and genetic organization in the bacterial genome, Algp7 was found to be homologous to an M75 peptidase motif-containing EfeO, a component of a ferrous ion transporter. Despite the presence of an M75 peptidase motif with high similarity, the Algp7 protein purified from recombinant Escherichia coli cells was inert on insulin B chain and N-benzoyl-Phe-Val-Arg-p-nitroanilide, both of which are substrates for a typical M75 peptidase, imelysin, from Pseudomonas aeruginosa. The X-ray crystallographic structure of Algp7 was determined at 2.10 A resolution by single-wavelength anomalous diffraction. Although a metal-binding motif, HxxE, conserved in zinc ion-dependent M75 peptidases is also found in Algp7, the crystal structure of Algp7 contains no metal even at the motif. The protein consists of two structurally similar up-and-down helical bundles as the basic scaffold. A deep cleft between the bundles is sufficiently large to accommodate macromolecules such as alginate polysaccharide. This is the first structural report on a bacterial cell-surface alginate-binding protein with an M75 peptidase motif.

  10. Bacterial communities associated with the surfaces of fresh fruits and vegetables.

    Directory of Open Access Journals (Sweden)

    Jonathan W Leff

    Full Text Available Fresh fruits and vegetables can harbor large and diverse populations of bacteria. However, most of the work on produce-associated bacteria has focused on a relatively small number of pathogenic bacteria and, as a result, we know far less about the overall diversity and composition of those bacterial communities found on produce and how the structure of these communities varies across produce types. Moreover, we lack a comprehensive view of the potential effects of differing farming practices on the bacterial communities to which consumers are exposed. We addressed these knowledge gaps by assessing bacterial community structure on conventional and organic analogs of eleven store-bought produce types using a culture-independent approach, 16 S rRNA gene pyrosequencing. Our results demonstrated that the fruits and vegetables harbored diverse bacterial communities, and the communities on each produce type were significantly distinct from one another. However, certain produce types (i.e., sprouts, spinach, lettuce, tomatoes, peppers, and strawberries tended to share more similar communities as they all had high relative abundances of taxa belonging to the family Enterobacteriaceae when compared to the other produce types (i.e., apples, peaches, grapes, and mushrooms which were dominated by taxa belonging to the Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria phyla. Although potentially driven by factors other than farming practice, we also observed significant differences in community composition between conventional and organic analogs within produce types. These differences were often attributable to distinctions in the relative abundances of Enterobacteriaceae taxa, which were generally less abundant in organically-grown produce. Taken together, our results suggest that humans are exposed to substantially different bacteria depending on the types of fresh produce they consume with differences between conventionally and organically

  11. Effect of Ultraviolet Light Irradiation Combined with Riboflavin on Different Bacterial Pathogens from Ocular Surface Infection

    OpenAIRE

    Shen, Jing; Liang, Qingfeng; Su, Guanyu; Zhang, Yang; Wang, Zhiqun; Liang, Hong; Baudouin, Christophe; Labbé, Antoine

    2017-01-01

    In order to study Staphylococcus epidermis and Staphylococcus aureus in vitro viability after the exposure to ultraviolet (UV) light and riboflavin, twelve strains of Staphylococcus epidermis and twelve strains of Staphylococcus aureus were isolated from patients with bacterial keratitis. The growth situation of Staphylococcus epidermidis and Staphylococcus aureus under different experimental conditions was qualitatively observed. The number of colonies surviving bacteria was counted under di...

  12. Raman and surface-enhanced Raman spectroscopy of amino acids and nucleotide bases for target bacterial vibrational mode identification

    Science.gov (United States)

    Guicheteau, Jason; Argue, Leanne; Hyre, Aaron; Jacobson, Michele; Christesen, Steven D.

    2006-05-01

    Raman and surface-enhanced Raman spectroscopy (SERS) studies of bacteria have reported a wide range of vibrational mode assignments associated with biological material. We present Raman and SER spectra of the amino acids phenylalanine, tyrosine, tryptophan, glutamine, cysteine, alanine, proline, methionine, asparagine, threonine, valine, glycine, serine, leucine, isoleucine, aspartic acid and glutamic acid and the nucleic acid bases adenosine, guanosine, thymidine, and uridine to better characterize biological vibrational mode assignments for bacterial target identification. We also report spectra of the bacteria Bacillus globigii, Pantoea agglomerans, and Yersinia rhodei along with band assignments determined from the reference spectra obtained.

  13. Risk factors for otitis media in children with special emphasis on the role of colonization with bacterial airway pathogens: The Generation R study

    NARCIS (Netherlands)

    J.A.M. Labout (Joost); L. Duijts (Liesbeth); A. Lebon (Ankie); R. de Groot (Ronald); A. Hofman (Albert); V.W.V. Jaddoe (Vincent); H.A. Verbrugh (Henri); P.W.M. Hermans (Peter); H.A. Moll (Henriëtte)

    2011-01-01

    textabstractAcute otitis media is the most frequent diagnosis in children visiting physicians' offices. Risk factors for otitis media have been widely studied. Yet, the correlation between bacterial carriage and the development of otitis media is not entirely clear. Our aim was to study in a

  14. Risk factors for otitis media in children with special emphasis on the role of colonization with bacterial airway pathogens: the Generation R study

    NARCIS (Netherlands)

    Labout, J.A.; Duijts, L.; Lebon, A.; Groot, R. de; Hofman, A.; Jaddoe, V.V.; Verbrugh, H.A.; Hermans, P.W.M.; Moll, H.A.

    2011-01-01

    Acute otitis media is the most frequent diagnosis in children visiting physicians' offices. Risk factors for otitis media have been widely studied. Yet, the correlation between bacterial carriage and the development of otitis media is not entirely clear. Our aim was to study in a population-based

  15. A Role for the RNA Chaperone Hfq in Controlling Adherent-Invasive Escherichia coli Colonization and Virulence

    DEFF Research Database (Denmark)

    Simonsen, Karina T; Nielsen, Gorm; Bjerrum, Janni Vester

    2011-01-01

    strain LF82 forms a persistent infection in C. elegans, thereby reducing the host lifespan significantly. This host killing phenotype was associated with massive bacterial colonization of the nematode intestine and damage to the intestinal epithelial surface. C. elegans killing was independent of known...

  16. Development of a high-efficient transformation system of Bacillus pumilus strain DX01 to facilitate gene isolation via gfp-tagged insertional mutagenesis and visualize bacterial colonization of rice roots.

    Science.gov (United States)

    Shen, Xinqian; Chen, Yunpeng; Liu, Tong; Hu, Xiaolu; Gu, Zhenfang

    2013-09-01

    A Tn5 transposition vector, pMOD-tet-egfp, was constructed and used for the random insertional mutagenesis of Bacillus pumilus. Various parameters were investigated to increase the transformation efficiency B. pumilus DX01 via Tn5 transposition complexes (transposome): bacterial growth phase, type of electroporation buffer, electric field strength, and recovery medium. Transformation efficiency was up to 3 × 10(4) transformants/μg of DNA under the optimized electroporation conditions, and a total of 1,467 gfp-tagged transformants were obtained. Fluorescence-activated cell sorting analysis showed that all gfp-tagged bacterial cells expressed GFP, indicating that foreign DNA has been successfully integrated into the genome of B. pumilus and expressed. Finally, flanking DNA sequences were isolated from several transformants and colonization of rice roots by B. pumilus DX01 was also studied. The method developed here will be useful for creating an insertion mutant library of gram-positive bacteria, thus facilitating their molecular genetic and cytological studies.

  17. Hijacking Complement Regulatory Proteins for Bacterial Immune Evasion.

    Science.gov (United States)

    Hovingh, Elise S; van den Broek, Bryan; Jongerius, Ilse

    2016-01-01

    The human complement system plays an important role in the defense against invading pathogens, inflammation and homeostasis. Invading microbes, such as bacteria, directly activate the complement system resulting in the formation of chemoattractants and in effective labeling of the bacteria for phagocytosis. In addition, formation of the membrane attack complex is responsible for direct killing of Gram-negative bacteria. In turn, bacteria have evolved several ways to evade complement activation on their surface in order to be able to colonize and invade the human host. One important mechanism of bacterial escape is attraction of complement regulatory proteins to the microbial surface. These molecules are present in the human body for tight regulation of the complement system to prevent damage to host self-surfaces. Therefore, recruitment of complement regulatory proteins to the bacterial surface results in decreased complement activation on the microbial surface which favors bacterial survival. This review will discuss recent advances in understanding the binding of complement regulatory proteins to the bacterial surface at the molecular level. This includes, new insights that have become available concerning specific conserved motives on complement regulatory proteins that are favorable for microbial binding. Finally, complement evasion molecules are of high importance for vaccine development due to their dominant role in bacterial survival, high immunogenicity and homology as well as their presence on the bacterial surface. Here, the use of complement evasion molecules for vaccine development will be discussed.

  18. Bacterial Adhesion Forces with Substratum Surfaces and the Susceptibility of Biofilms to Antibiotics

    OpenAIRE

    Muszanska, Agnieszka K.; Nejadnik, M. Reza; Chen, Yun; van den Heuvel, Edwin R.; Busscher, Henk J.; van der Mei, Henny C.; Norde, Willem

    2012-01-01

    Biofilms causing biomaterial-associated infection resist antibiotic treatment and usually necessitate the replacement of infected implants. Here we relate bacterial adhesion forces and the antibiotic susceptibility of biofilms on uncoated and polymer brush-coated silicone rubber. Nine strains of Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa adhered more weakly to brush-coated silicone rubber (−0.05 ± 0.03 to −0.51 ± 0.62 nN) than to uncoated silicone rubber (−1...

  19. Protein and bacterial fouling characteristics of peptide and antibody decorated surfaces of PEG-poly(acrylic acid) co-polymers.

    Science.gov (United States)

    Wagner, Victoria E; Koberstein, Jeffrey T; Bryers, James D

    2004-05-01

    The potential for base poly(ethylene glycol) graft poly(acrylic acid) PEG-g-PA copolymers and surface-modified PEG-g-PA materials to inhibit random protein fouling and bacterial adhesion are investigated. PEG-g-PA co-polymers were synthesized that inhibited non-specific protein and cellular adhesion. PEG-g-PA co-polymers were then covalently modified with either cell adhesion peptides (YRGDS, YEILDV) or fragments of antibodies to monocyte/macrophage integrin receptors (Anti-VLA4, Anti-beta1, Anti-beta2, and Anti-CD64) known to enhance macrophage adhesion and, perhaps, modulate their activation. Materials produced in this work were characterized using: hydrophobicity by contact angle; angle-resolved X-ray Photoelectron Spectroscopy to confirm the presence of PEG in the bulk material and the surface; degree of hydration; differential scanning calorimetry; and thermal gravimetric analysis. To evaluate the non-fouling efficacy of the various modified surfaces, three proteins, human serum albumin, human fibronectin (Fraction I) and human immunoglobulin were 125I labeled. Samples of base PEG-g-PA and PEG-g-PA, modified with various peptides, were exposed to solutions containing either 2 or 200 microg/ml of one of the labeled proteins at 37 degrees C for 24 h. PEG-g-PA substrata modified with directly bound peptides exhibited protein adsorption that varied depending upon the surface bounded peptide. PEG-g-PA modified with peptides linked by linear PEG tethers reduced protein adsorption at 24 h by approximately 45% in comparison to PEG-g-PA. Peptides linked by way of StarPEO and StarlikePEO tethers further decreased protein adsorption in comparison to PEG-g-PA. The ability of peptide:PEOtethers to inhibit protein adsorption appeared to be a function of type and surface coverage of the PEO tether and not influenced by the amount or molecular structure the tethered peptide. Peptides directly coupled to the PEG-g-PA increased the amount of protein fouling relative to controls

  20. The impact of date palm fruits and their component polyphenols, on gut microbial ecology, bacterial metabolites and colon cancer cell proliferation

    OpenAIRE

    Eid, Noura; Enani, Sumia; Walton, Gemma; Corona, Giulia; Costabile, Adele; Gibson, Glenn; Rowland, Ian; Spencer, Jeremy P. E.

    2014-01-01

    The fruit of the date palm (Phoenix dactylifera L.) is a rich source of dietary fibre and polyphenols. We have investigated gut bacterial changes induced by the whole date fruit extract (digested date extract; DDE) and its polyphenol-rich extract (date polyphenol extract; DPE) using faecal, pH-controlled, mixed batch cultures mimicking the distal part of the human large intestine, and utilising an array of microbial group-specific 16S rRNA oligonucleotide probes. Fluorescence microscopic enum...

  1. Identification of a Supramolecular Functional Architecture of Streptococcus mutans Adhesin P1 on the Bacterial Cell Surface*

    Science.gov (United States)

    Heim, Kyle P.; Sullan, Ruby May A.; Crowley, Paula J.; El-Kirat-Chatel, Sofiane; Beaussart, Audrey; Tang, Wenxing; Besingi, Richard; Dufrene, Yves F.; Brady, L. Jeannine

    2015-01-01

    P1 (antigen I/II) is a sucrose-independent adhesin of Streptococcus mutans whose functional architecture on the cell surface is not fully understood. S. mutans cells subjected to mechanical extraction were significantly diminished in adherence to immobilized salivary agglutinin but remained immunoreactive and were readily aggregated by fluid-phase salivary agglutinin. Bacterial adherence was restored by incubation of postextracted cells with P1 fragments that contain each of the two known adhesive domains. In contrast to untreated cells, glutaraldehyde-treated bacteria gained reactivity with anti-C-terminal monoclonal antibodies (mAbs), whereas epitopes recognized by mAbs against other portions of the molecule were masked. Surface plasmon resonance experiments demonstrated the ability of apical and C-terminal fragments of P1 to interact. Binding of several different anti-P1 mAbs to unfixed cells triggered release of a C-terminal fragment from the bacterial surface, suggesting a novel mechanism of action of certain adherence-inhibiting antibodies. We also used atomic force microscopy-based single molecule force spectroscopy with tips bearing various mAbs to elucidate the spatial organization and orientation of P1 on living bacteria. The similar rupture lengths detected using mAbs against the head and C-terminal regions, which are widely separated in the tertiary structure, suggest a higher order architecture in which these domains are in close proximity on the cell surface. Taken together, our results suggest a supramolecular organization in which additional P1 polypeptides, including the C-terminal segment originally identified as antigen II, associate with covalently attached P1 to form the functional adhesive layer. PMID:25666624

  2. Colon interposition

    International Nuclear Information System (INIS)

    Isolauri, J.; Tampere Univ. Central Hospital; Paakkala, T.; Arajaervi, P.; Markkula, H.

    1987-01-01

    Colon interposition was carried out in 12 patients with oesophageal carcinoma and on 38 patients with benign oesophageal disease an average of 71 months before the radiographic examination. Various ischaemic changes including 'jejunization', loss of haustration and stricture formation were observed in 15 cases. In 12 patients one or several diverticula were seen in the colon graft. Reflux was observed in 17 cases in supine position. Double contrast technique in the examination of interposed colon is recommended. (orig.)

  3. Comparing Methods of Separating Bacterial Biofilms on the Surface of Water Transportation Pipes and Equipment of Milking in the Farms

    Directory of Open Access Journals (Sweden)

    setareh nabizadeh

    2016-08-01

    Full Text Available Introduction Bacterial biofilms can be both useful and harmful based on their combination and locations. Biofilm formation occurs as a stepwise process. Their formation in liquid transportation pipes used for milking system and drinking water in animal farms may create some problems and is a potential source of pollution. Speed of biofilm formation depends on many factors including: construction and functional characteristics of bacteria, the composition and culture conditions such as temperature and substratum. In this research the Bacillus subtillis bacteria with special characteristics was selected due to its capability for biofilm creation. Bacillus subtillis bacteria is mobility and a stronger connection than other bacteria levels are created. In the research conducted in the biofilm there are many resources on biofilm formation by Bacillus subtillis bacteria. Bacillus subtillis is saprophytic in the soil, water and air. There is also the ability to form spores of Bacillus subtillis. Materials and Methods Firstly the possibility of creating biofilms on different Plastic (polyvinilchlorid, polypropylene, polyethylengelycole, alluminum and glass surfaces in three temperatures of 4°C, 30°C and 37°C were studied. Two different methods of biofilms separation including separating swap and vortex were tested and their efficienceies were calculated. After biofilm formation on parts of the vortex separation method after washing parts in sterile conditions in a tube containing normal saline for 4 minutes was vortex. The bacterial suspension decreasing dilution series was created. Pour plate in medium using agar plate count agar and was cultured at 30°C for 24-48 hours. Numbers of colonies were counted. The numbers of biofilm cells were calculated. In swap method after biofilm formation on parts using a cotton swap was isolated biofilms. The swap was transferred to tube containing normal saline and the bacterial suspension decreasing dilution

  4. Vaginal epithelial cells regulate membrane adhesiveness to co-ordinate bacterial adhesion.

    Science.gov (United States)

    Younes, Jessica A; Klappe, Karin; Kok, Jan Willem; Busscher, Henk J; Reid, Gregor; van der Mei, Henny C

    2016-04-01

    Vaginal epithelium is colonized by different bacterial strains and species. The bacterial composition of vaginal biofilms controls the balance between health and disease. Little is known about the relative contribution of the epithelial and bacterial cell surfaces to bacterial adhesion and whether and how adhesion is regulated over cell membrane regions. Here, we show that bacterial adhesion forces with cell membrane regions not located above the nucleus are stronger than with regions above the nucleus both for vaginal pathogens and different commensal and probiotic lactobacillus strains involved in health. Importantly, adhesion force ratios over membrane regions away from and above the nucleus coincided with the ratios between numbers of adhering bacteria over both regions. Bacterial adhesion forces were dramatically decreased by depleting the epithelial cell membrane of cholesterol or sub-membrane cortical actin. Thus, epithelial cells can regulate membrane regions to which bacterial adhesion is discouraged, possibly to protect the nucleus. © 2015 John Wiley & Sons Ltd.

  5. The Design of Simple Bacterial Microarrays: Development towards Immobilizing Single Living Bacteria on Predefined Micro-Sized Spots on Patterned Surfaces.

    Directory of Open Access Journals (Sweden)

    Nina Bjørk Arnfinnsdottir

    Full Text Available In this paper we demonstrate a procedure for preparing bacterial arrays that is fast, easy, and applicable in a standard molecular biology laboratory. Microcontact printing is used to deposit chemicals promoting bacterial adherence in predefined positions on glass surfaces coated with polymers known for their resistance to bacterial adhesion. Highly ordered arrays of immobilized bacteria were obtained using microcontact printed islands of polydopamine (PD on glass surfaces coated with the antiadhesive polymer polyethylene glycol (PEG. On such PEG-coated glass surfaces, bacteria were attached to 97 to 100% of the PD islands, 21 to 62% of which were occupied by a single bacterium. A viability test revealed that 99% of the bacteria were alive following immobilization onto patterned surfaces. Time series imaging of bacteria on such arrays revealed that the attached bacteria both divided and expressed green fluorescent protein, both of which indicates that this method of patterning of bacteria is a suitable method for single-cell analysis.

  6. Bacterial adhesion forces with substratum surfaces and the susceptibility of biofilms to antibiotics.

    Science.gov (United States)

    Muszanska, Agnieszka K; Nejadnik, M Reza; Chen, Yun; van den Heuvel, Edwin R; Busscher, Henk J; van der Mei, Henny C; Norde, Willem

    2012-09-01

    Biofilms causing biomaterial-associated infection resist antibiotic treatment and usually necessitate the replacement of infected implants. Here we relate bacterial adhesion forces and the antibiotic susceptibility of biofilms on uncoated and polymer brush-coated silicone rubber. Nine strains of Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa adhered more weakly to brush-coated silicone rubber (-0.05 ± 0.03 to -0.51 ± 0.62 nN) than to uncoated silicone rubber (-1.05 ± 0.46 to -5.1 ± 1.3 nN). Biofilms of weakly adhering organisms on polymer brush coatings remained in a planktonic state, susceptible to gentamicin, unlike biofilms formed on uncoated silicone rubber.

  7. Multidrug resistance phenotypes are widespread over different bacterial taxonomic groups thriving in surface water.

    Science.gov (United States)

    Narciso-da-Rocha, Carlos; Manaia, Célia M

    2016-09-01

    The environment is the original and most ancient source of the antibiotic resistance determinants that threat the human health nowadays. In the environment, water is a privileged habitat and mode of dissemination of bacteria of different origins. Freshwater bodies that cross urban areas are supposed to hold a complex mixture of both human/animal origin and strictly environmental bacteria. In this study, we were interested in unveiling the bacterial diversity in urban river transects and, simultaneously, investigate the occurrence of antibiotic resistant bacteria, in particular the multidrug resistant (MDR). With this aim, water and sediments of two rivers were sampled from an urban transect and the bacterial diversity was assessed based on 16S rRNA gene-based community analysis and, simultaneously, total heterotrophic bacteria were isolated in the presence and in the absence of antibiotics. The three predominant phyla were Proteobacteria, Bacteroidetes and Actinobacteria, in water, or Acidobacteria, in sediments. MDR bacteria were observed to belong to the predominant phyla observed in water, mostly of the classes Gamma- and Betaproteobacteria (Proteobacteria) and Sphingobacteriia and Flavobacteriia (Bacteroidetes) and belonged to genera of ubiquitous (Pseudomonas, Acinetobacter, Stenotrophomonas) or mainly environmental (Chitinophaga, Chryseobacterium) bacteria. The observation that MDR bacteria are widespread in the environment and over distinct phylogenetic lineages has two relevant implications: i) the potential of environmental bacteria as source or facilitators for antibiotic resistance acquisition; ii) the need to complement culture-independent methods with culture-based approaches in order to identify major sources of MDR profiles. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Effectiveness of different cleaning agents against the colonization of Candida spp and the in vitro detection of the adherence of these yeast cells to denture acrylic surfaces.

    Science.gov (United States)

    Nalbant, A Dilek; Kalkanci, Ayse; Filiz, Banu; Kustimur, Semra

    2008-08-30

    The aim of this study is to examine the effect Klorhex and Fittydent, which are used as cleaning agents on the adhesion of Candida on the surfaces of acrylic denture and palatal mucosa. In addition, ability of yeasts to adhere to acrylic strips was evaluated after applying these agents in vitro. Each group of 15 patients cleaned their dentures with either Klorhex or with Fittydent. The control group cleaned their dentures with water. It was found that 62.2% of the patients had colonies of Candida species on their palatal mucosa which was reduced to 51.1% after using these cleaning agents. The colonization rate with Candida spp on their dentures was reduces from 82.2% to 68.8% using these cleaning agents. The mean adhesion value of the Candida strains isolated from the acrylic strips were found to be 75 cell/strip prior to applying the Klorhex and Fittydent and 37.5 cell/strip and 15 cell/strip after applying these agents, respectively. These results showed that Klorhex and Fittydent have a certain preventive effect on the colonization rate of Candida spp on the surface of these dentures, the palatal mucosa, as well as on the acrylic strips in vitro.

  9. Effectiveness of Different Cleaning Agents against the Colonization of Candida spp and the in Vitro Detection of the Adherence of These Yeast Cells to Denture Acrylic Surfaces

    Science.gov (United States)

    Kalkanci, Ayse; Filiz, Banu; Kustimur, Semra

    2008-01-01

    Purpose The aim of this study is to examine the effect Klorhex and Fittydent, which are used as cleaning agents on the adhesion of Candida on the surfaces of acrylic denture and palatal mucosa. In addition, ability of yeasts to adhere to acrylic strips was evaluated after applying these agents in vitro. Materials and Methods Each group of 15 patients cleaned their dentures with either Klorhex or with Fittydent. The control group cleaned their dentures with water. Results It was found that 62.2% of the patients had colonies of Candida species on their palatal mucosa which was reduced to 51.1% after using these cleaning agents. The colonization rate with Candida spp on their dentures was reduces from 82.2% to 68.8% using these cleaning agents. The mean adhesion value of the Candida strains isolated from the acrylic strips were found to be 75 cell/strip prior to applying the Klorhex and Fittydent and 37.5 cell/strip and 15 cell/strip after applying these agents, respectively. Conclusion These results showed that Klorhex and Fittydent have a certain preventive effect on the colonization rate of Candida spp on the surface of these dentures, the palatal mucosa, as well as on the acrylic strips in vitro. PMID:18729309

  10. Development of non-pathogenic bacterial biofilms on the surface of stainless steel which are inhibitory to Salmonella enterica.

    Science.gov (United States)

    Kim, Yoonbin; Kim, Hoikyung; Beuchat, Larry R; Ryu, Jee-Hoon

    2018-02-01

    Non-pathogenic bacterial biofilms were developed on the surface of stainless steel possessing desiccation tolerance and antimicrobial activity against Salmonella enterica. Three bacteria exhibiting strong antimicrobial activities against S. enterica were isolated from various soils, foods, and food-contact surfaces. Isolates were identified as Pseudomonas extremorientalis (strain Lettuce-28), Paenibacillus peoriae (strain Lettuce-7), and Streptomyces cirratus (strain Geumsan-207). These bacteria grew rapidly and formed biofilms within 24 h on the surface of stainless steel coupons (SSCs) immersed in laboratory media (tryptic soy broth or Bennet's broth) at 25 °C. Cells in biofilms had enhanced tolerance to desiccation (exposure to 43% atmospheric relative humidity [RH]) and retained antimicrobial activity against S. enterica. Populations of S. enterica deposited on SSCs containing biofilm formed by Ps. extremorientalis strain Lettuce-28, for example, decreased by > 2.5 log CFU/coupon within 24 h at 25 °C and 43% RH, while the number of cells inoculated on SSCs lacking biofilm decreased by 1.5 log CFU/coupon. Antimicrobial activities of the three antagonistic bacteria against S. enterica persisted in desiccated biofilms. This study provides insights to developing strategies to inactivate Salmonella and perhaps other foodborne pathogens on abiotic surfaces using non-pathogenic antagonistic bacteria. Copyright © 2017. Published by Elsevier Ltd.

  11. Switching of bacterial adhesion to a glycosylated surface by reversible reorientation of the carbohydrate ligand

    DEFF Research Database (Denmark)

    Weber, Theresa; Chrasekaran, Vijayan; Stamer, Insa

    2014-01-01

    The surface recognition in many biological systems is guided by the interaction of carbohydrate-specific proteins (lectins) with carbohydrate epitopes (ligands) located within the unordered glycoconjugate layer (glycocalyx) of cells. Thus, for recognition, the respective ligand has to reorient...

  12. Residual viral and bacterial contamination of surfaces after cleaning and disinfection

    NARCIS (Netherlands)

    Tuladhar, E.; Hazeleger, W.C.; Koopmans, M.; Zwietering, M.H.; Beumer, R.R.; Duizer, E.

    2012-01-01

    Environmental surfaces contaminated with pathogens can be sources of indirect transmission, and cleaning and disinfection are common interventions focused on reducing contamination levels. We determined the efficacy of cleaning and disinfection procedures for reducing contamination by noroviruses,

  13. Effects of farmhouse hotel and paper mill effluents on bacterial community structures in sediment and surface water of Nanxi River, China.

    Science.gov (United States)

    Lu, Xiao-Ming; Lu, Peng-Zhen

    2014-11-01

    The pyrosequencing technique was used to evaluate bacterial community structures in sediment and surface water samples taken from Nanxi River receiving effluents from a paper mill and a farmhouse hotel, respectively. For each sample, 4,610 effective bacterial sequences were selected and used to do the analysis of diversity and abundance, respectively. Bacterial phylotype richness in the sediment sample without effluent input was higher than the other samples, and the surface water sample with addition of effluent from the paper mill contained the least richness. Effluents from both the paper mill and farmhouse hotel have a potential to reduce the bacterial diversity and abundance in the sediment and surface water, especially it is more significant in the sediment. The effect of the paper mill effluent on the sediment and surface water bacterial communities was more serious than that of the farmhouse hotel effluent. Characterization of microbial community structures in the sediment and surface water from two tributaries of the downstream river indicated that various effluents from the paper mill and farmhouse hotel have the similar potential to decrease the natural variability in riverine microbial ecosystems.

  14. Colonic angiodysplasia

    Energy Technology Data Exchange (ETDEWEB)

    Vallee, C.; Legmann, P.; Garnier, T.; Levesque, M.; Favriel, J.M.

    1984-11-01

    The main clinical, endoscopic and radiographic findings in thirty documented cases of colonic angiodysplasia or vacular ectasia are described. We emphasise the association with colonic diverticulosis and cardiovascular pathology, describe the histological changes, summarize the present physiopathological hypothesis, and consider the various therapeutic approaches.

  15. Colonic angiodysplasia

    International Nuclear Information System (INIS)

    Vallee, C.; Legmann, P.; Garnier, T.; Levesque, M.

    1984-01-01

    The main clinical, endoscopic and radiographic findings in thirty documented cases of colonic angiodysplasia or vacular ectasia are described. We emphasise the association with colonic diverticulosis and cardiovascular pathology, describe the histological changes, summarize the present physiopathological hypothesis, and consider the various therapeutic approaches. (orig.)

  16. Colonic locomotion

    NARCIS (Netherlands)

    Dodou, D.

    2006-01-01

    The most effective screening method for colonic cancer is colonoscopy. However, colonoscopy cannot be easily embraced by the population because of the related pain intensity. Robotic devices that pull themselves forward through the colon are a possible alternative. The main challenge for such

  17. Colonic lipoma

    International Nuclear Information System (INIS)

    Siddiqui, M.S.; Khatri, A.R.; Quraishy, M.S.; Fatima, L.; Muzaffar, S.

    2003-01-01

    Lipoma of the colon is rare and may lead to intestinal obstruct. We have presented two cases of colonic lipoma. Both were elderly females, one presented with diarrhea and the other with sub-acute intestinal obstruction. After colonoscopy surgical removal was done. Histopathology revealed lipoma. (author)

  18. Issues in determining factors influencing bacterial attachment: a review using the attachment of Escherichia coli to abiotic surfaces as an example.

    Science.gov (United States)

    Goulter, R M; Gentle, I R; Dykes, G A

    2009-07-01

    An understanding of the mechanisms which facilitate the attachment of Escherichia coli and other bacterial species to abiotic surfaces is desired by numerous industries including the food and medical industries. Numerous studies have attempted to explain bacterial attachment as a function of bacterial properties such as cellular surface charge, hydrophobicity and outer membrane proteins amongst others. Conflicting evidence in the literature both for and against a positive relationship may arise from the nature of the test methods used to measure them. A handful of recent studies utilizing technologies such as atomic force microscopy have begun to look at bacterial attachment at a single cell and molecular level. These studies may provide the information required to fully understand the underlying factors which influence bacterial cell attachment to abiotic surfaces. A number of issues in determining the influential factors of bacterial attachment have been identified from the literature: a lack of standardization and sensitivity of methods, as well as the value of measuring bulk properties of a number of cells rather than the behaviour of single cells which may overlook key interactions at a molecular level. These issues will need to be addressed in future studies in this area.

  19. Bacterial resistance control on mineral surfaces of hydroxyapatite and human teeth via surface charge-driven antifouling coatings.

    Science.gov (United States)

    Venault, Antoine; Yang, Hui-Shan; Chiang, Yen-Che; Lee, Bor-Shuinn; Ruaan, Ruoh-Chyu; Chang, Yung

    2014-03-12

    This works reports a set of new functionalized polyethyleneimine (PEI) polymers, including a neutral PEGylated polymer PEI-g-PEGMA, a negatively charged polymer PEI-g-SA, and a zwitterionic polymer PEI-g-SBMA, and their use as antibiofouling coating agent for human teeth protection. Polymers were synthesized by Michael addition, XPS analysis revealed that each polymer could be efficiently coated onto hydroxyapatite, ceramic material used as a model tooth. Polymers carrying a negative net charge were more efficiently adsorbed, because of the establishment of electrostatic interactions with calcium ions. Protein adsorption tests revealed that two factors were important in the reduction of protein adsorption. Both the surface charge and the surface ability to bind and entrap water molecules had to be considered. PEI-g-SBMA, which zeta potential in PBS solution was negative, was efficient to inhibit the adsorption of BSA, a negative protein. On the other hand, it also resisted the adsorption of lysozyme, a positive protein, because zwitterionic molecules can easily entrap water and provide a very hydrophilic environment. Streptococcus mutans attachment tests performed unveiled that all modified polymers were efficient to resist this type of bacteria responsible for dental carries. Best results were also obtained with PEI-g-SBMA coating. This polymer was also shown to efficiently resist the adsorption of positively charged bacteria (Stenotrophomonas maltophilia). Tests performed on real human tooth showed that PEI-g-SBMA could inhibit up to 70% of bacteria adhesion, which constitutes a major result considering that surface of teeth is very rough, therefore physically promoting the attachment of proteins and bacteria.

  20. Leucine, starch and bicarbonate utilization by specific bacterial groups in surface shelf waters off Galicia (NW Spain).

    Science.gov (United States)

    Teira, E; Hernando-Morales, V; Guerrero-Feijóo, E; Varela, M M

    2017-06-01

    The capability of different bacterial populations to degrade abundant polymers, such as algal-derived polysaccharides, or to utilize preferentially polymers over monomers, remains largely unknown. In this study, microautoradiography was combined with fluorescence in situ hybridization (MAR-FISH) to evaluate the ability of Bacteroidetes, SAR11, Roseobacter spp., Gammaproteobacteria and SAR86 cells to use bicarbonate, leucine and starch under natural light conditions at two locations in shelf surface waters off NW Spain. The percentage of cells incorporating bicarbonate was relatively high (mean 32% ± 4%) and was positively correlated with the intensity of solar radiation. The proportion of cells using starch (mean 56% ± 4%) or leucine (mean 47% ± 4%) was significantly higher than that using bicarbonate. On average, SAR11, Roseobacter spp. and Gammaproteobacteria showed a similarly high percentage of cells using leucine (47%-65% of hybridized cells) than using starch (51%-64% of hybridized cells), while Bacteroidetes and SAR86 cells preferentially used starch (53% of hybridized cells) over leucine (34%-40% of hybridized cells). We suggest that the great percentage of bacteria using starch is related to a high ambient availability of polymers associated to algal cell lysis, which, in turn, weakens the short-term coupling between phytoplankton release and bacterial production. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  1. Bacterial inhibiting surfaces caused by the effects of silver release and/or electrical field

    DEFF Research Database (Denmark)

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

    2008-01-01

    In this study, silver-palladium surfaces and silver-bearing stainless steels were designed and investigated focusing on electrochemical principles to form inhibiting effects on planktonic and/or biofilm bacteria in water systems. Silver-resistant Escherichia coli and silver-sensitive E. coli were...... used for the evaluation of inhibiting effects and the inhibiting mechanism. For silver-palladium surfaces combined with bacteria in media, the inhibiting effect was a result of electrochemical interactions and/or electrical field, and in some specific media, such as ammonium containing, undesired...... silver ions release can occur from their Surfaces. For silver-bearing stainless steels, the inhibiting effect can only be explained by high local silver ions release. and can be limited or deactivated dependent on the specific environment. (c) 2008 Elsevier Ltd. All rights reserved....

  2. Surface-functionalized gold nanoparticles mediate bacterial transformation: a nanobiotechnological approach.

    Science.gov (United States)

    Chatterjee, Saptarshi; Sarkar, Keka

    2014-02-01

    Transformation of bacteria is an important step in molecular biology. Viral and non-virus-based gene delivery techniques, including chemical/biological and physical approaches, have been applied to bacterial, mammalian and plant cells. E. coli is not competent to take up DNA; hence, different methods are used to incorporate plasmid DNA. A novel method has been developed using glutathione-functionalized gold nanoparticles to mediate transformation of plasmid DNA (pUC19) into E. coli DH5α that does not require the preparation of competent cells. The glutathione-functionalized gold nanoparticles acted as a vector and facilitated the entry of DNA into the host cell. The method also gave a higher transformation efficiency (4.2 × 10(7)/μg DNA) compared to 2.3 × 10(5)/μg DNA using the conventional CaCl2-mediated method. It was also non-toxic to the bacterium making it suitable for biotechnological applications.

  3. Effect of Ultraviolet Light Irradiation Combined with Riboflavin on Different Bacterial Pathogens from Ocular Surface Infection

    Science.gov (United States)

    Su, Guanyu; Zhang, Yang; Wang, Zhiqun; Liang, Hong; Baudouin, Christophe; Labbé, Antoine

    2017-01-01

    In order to study Staphylococcus epidermis and Staphylococcus aureus in vitro viability after the exposure to ultraviolet (UV) light and riboflavin, twelve strains of Staphylococcus epidermis and twelve strains of Staphylococcus aureus were isolated from patients with bacterial keratitis. The growth situation of Staphylococcus epidermidis and Staphylococcus aureus under different experimental conditions was qualitatively observed. The number of colonies surviving bacteria was counted under different UV light power and different exposure time. The experiment showed that there was no inhibition effect on the growth of bacteria using riboflavin alone. In UV alone group and UV-riboflavin group, inhibition effect on the bacteria growth was found. The UV-riboflavin combination had better inhibition effect on bacteria than UV irradiation alone. The amount of bacteria in the UV-riboflavin group was decreased by 99.1%~99.5% and 54.8%~64.6% in the UV alone group, when the UV light power was 10.052 mW/cm2 and the irradiation time was 30 min. Moreover, with the increase of the UV power or irradiation time, the survival rates of bacteria were rapidly reduced. Compared with Staphylococcus aureus, Staphylococcus epidermis was more easily to be killed under the action of UV light combined with riboflavin. PMID:29158733

  4. Effect of Ultraviolet Light Irradiation Combined with Riboflavin on Different Bacterial Pathogens from Ocular Surface Infection.

    Science.gov (United States)

    Shen, Jing; Liang, Qingfeng; Su, Guanyu; Zhang, Yang; Wang, Zhiqun; Liang, Hong; Baudouin, Christophe; Labbé, Antoine

    2017-01-01

    In order to study Staphylococcus epidermis and Staphylococcus aureus in vitro viability after the exposure to ultraviolet (UV) light and riboflavin, twelve strains of Staphylococcus epidermis and twelve strains of Staphylococcus aureus were isolated from patients with bacterial keratitis. The growth situation of Staphylococcus epidermidis and Staphylococcus aureus under different experimental conditions was qualitatively observed. The number of colonies surviving bacteria was counted under different UV light power and different exposure time. The experiment showed that there was no inhibition effect on the growth of bacteria using riboflavin alone. In UV alone group and UV-riboflavin group, inhibition effect on the bacteria growth was found. The UV-riboflavin combination had better inhibition effect on bacteria than UV irradiation alone. The amount of bacteria in the UV-riboflavin group was decreased by 99.1%~99.5% and 54.8%~64.6% in the UV alone group, when the UV light power was 10.052 mW/cm 2 and the irradiation time was 30 min. Moreover, with the increase of the UV power or irradiation time, the survival rates of bacteria were rapidly reduced. Compared with Staphylococcus aureus , Staphylococcus epidermis was more easily to be killed under the action of UV light combined with riboflavin.

  5. Interactions between bacteria and solid surfaces in relation to bacterial transport in porous media

    NARCIS (Netherlands)

    Rijnaarts, H.H.M.

    1994-01-01

    Interactions between bacteria and solid surfaces strongly influence the behaviour of bacteria in natural and engineered ecosystems. Many biofilm reactors and terrestrial environments are porous media. The purpose of the research presented in this thesis is to gain a better insight into the

  6. Bacterial adhesion and biofilm formation on surfaces of variable roughness and hydrophobicity

    DEFF Research Database (Denmark)

    Tang, Lone; Pillai, Saju; Iversen, Anders

    L.Biofilm formation on surfaces in food production and processing can deteriorate the quality of food products and be a hazard to consumers. The food industry currently uses a number of approaches to either remove biofilm or prevent its formation. Due to the inherent resilience of bacteria...

  7. Motility and Chemotaxis Mediate the Preferential Colonization of Gastric Injury Sites by Helicobacter pylori

    Science.gov (United States)

    Aihara, Eitaro; Closson, Chet; Matthis, Andrea L.; Schumacher, Michael A.; Engevik, Amy C.; Zavros, Yana; Ottemann, Karen M.; Montrose, Marshall H.

    2014-01-01

    Helicobacter pylori (H. pylori) is a pathogen contributing to peptic inflammation, ulceration, and cancer. A crucial step in the pathogenic sequence is when the bacterium first interacts with gastric tissue, an event that is poorly understood in vivo. We have shown that the luminal space adjacent to gastric epithelial damage is a microenvironment, and we hypothesized that this microenvironment might enhance H. pylori colonization. Inoculation with 106 H. pylori (wild-type Sydney Strain 1, SS1) significantly delayed healing of acetic-acid induced ulcers at Day 1, 7 and 30 post-inoculation, and wild-type SS1 preferentially colonized the ulcerated area compared to uninjured gastric tissue in the same animal at all time points. Gastric resident Lactobacillus spp. did not preferentially colonize ulcerated tissue. To determine whether bacterial motility and chemotaxis are important to ulcer healing and colonization, we analyzed isogenic H. pylori mutants defective in motility (ΔmotB) or chemotaxis (ΔcheY). ΔmotB (106) failed to colonize ulcerated or healthy stomach tissue. ΔcheY (106) colonized both tissues, but without preferential colonization of ulcerated tissue. However, ΔcheY did modestly delay ulcer healing, suggesting that chemotaxis is not required for this process. We used two-photon microscopy to induce microscopic epithelial lesions in vivo, and evaluated accumulation of fluorescently labeled H. pylori at gastric damage sites in the time frame of minutes instead of days. By 5 min after inducing damage, H. pylori SS1 preferentially accumulated at the site of damage and inhibited gastric epithelial restitution. H. pylori ΔcheY modestly accumulated at the gastric surface and inhibited restitution, but did not preferentially accumulate at the injury site. H. pylori ΔmotB neither accumulated at the surface nor inhibited restitution. We conclude that bacterial chemosensing and motility rapidly promote H. pylori colonization of injury sites, and thereby biases

  8. Bacterial surface layer proteins as a novel capillary coating material for capillary electrophoretic separations

    Energy Technology Data Exchange (ETDEWEB)

    Moreno-Gordaliza, Estefanía, E-mail: emorenog@ucm.es [Division of Analytical Biosciences, Leiden Academic Centre for Drug Research, Universiteit Leiden, Einsteinweg 55, 2300, RA, Leiden (Netherlands); Department of Analytical Chemistry, Faculty of Chemistry, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040, Madrid (Spain); Stigter, Edwin C.A. [Division of Analytical Biosciences, Leiden Academic Centre for Drug Research, Universiteit Leiden, Einsteinweg 55, 2300, RA, Leiden (Netherlands); Department of Molecular Cancer Research, Universitair Medisch Centrum Utrecht, Wilhelmina Kinder Ziekenhuis, Lundlaan 6, 3584, EA Utrecht (Netherlands); Lindenburg, Petrus W.; Hankemeier, Thomas [Division of Analytical Biosciences, Leiden Academic Centre for Drug Research, Universiteit Leiden, Einsteinweg 55, 2300, RA, Leiden (Netherlands)

    2016-06-07

    A novel concept for stable coating in capillary electrophoresis, based on recrystallization of surface layer proteins on hydrophobized fused silica capillaries, was demonstrated. Surface layer protein A (SlpA) from Lactobacillus acidophilus bacteria was extracted, purified and used for coating pre-silanized glass substrates presenting different surface wettabilities (either hydrophobic or hydrophilic). Contact angle determination on SlpA-coated hydrophobic silica slides showed that the surfaces turned to hydrophilic after coating (53 ± 5°), due to a protein monolayer formation by protein-surface hydrophobic interactions. Visualization by atomic force microscopy demonstrated the presence of a SlpA layer on methylated silica slides displaying a surface roughness of 0.44 ± 0.02 nm. Additionally, a protein layer was visualized by fluorescence microscopy in methylated silica capillaries coated with SlpA and fluorescein isothiocyanate-labeled. The SlpA-coating showed an outstanding stability, even after treatment with 20 mM NaOH (pH 12.3). The electroosmotic flow in coated capillaries showed a partial suppression at pH 7.50 (3.8 ± 0.5 10{sup −9} m{sup 2} V{sup −1} s{sup −1}) when compared with unmodified fused silica (5.9 ± 0.1 10{sup −8} m{sup 2} V{sup −1} s{sup −1}). To demonstrate the potential of this novel coating, the SlpA-coated capillaries were applied for the first time for electrophoretic separation, and proved to be very suitable for the isotachophoretic separation of lipoproteins in human serum. The separations showed a high degree of repeatability (absolute migration times with 1.1–1.8% coefficient-of-variation (CV) within a day) and 2–3% CV inter-capillary reproducibility. The capillaries were stable for more than 100 runs at pH 9.40, and showed to be an exceptional alternative for challenging electrophoretic separations at long-term use. - Highlights: • New coating using recrystallized surface-layer proteins on

  9. Repurposing niclosamide as a versatile antimicrobial surface coating against device-associated, hospital-acquired bacterial infections.

    Science.gov (United States)

    Gwisai, Tinotenda; Hollingsworth, Nisha Rosita; Cowles, Sarah; Tharmalingam, Nagendran; Mylonakis, Eleftherios; Fuchs, Beth Burgwyn; Shukla, Anita

    2017-07-12

    Device-associated and hospital-acquired infections remain amongst the greatest challenges in regenerative medicine. Furthermore, the rapid emergence of antibiotic resistance and lack of new classes of antibiotics has made the treatment of these bacterial infections increasingly difficult. The repurposing of Food and Drug Administration approved drugs for antimicrobial therapies is a powerful means of reducing the time and cost associated with drug discovery and development. In this work, niclosamide, a commercially available anthelmintic drug with recently identified antimicrobial properties, was found to prevent the formation of, and combat existing biofilms of, several relevant Gram-positive bacteria, namely strains of Staphylococcus aureus, including methicillin resistant S. aureus (MRSA), and Staphylococcus epidermidis, all common causes of hospital-acquired and device-associated infections. This anti-biofilm activity was demonstrated at niclosamide concentrations as low as 0.01 μg ml -1 . We then assessed niclosamide activity as an antibacterial coating, which could potentially be applied to medical device surfaces. We developed solvent cast niclosamide coatings on a variety of surfaces common amongst medical devices including glass, titanium, stainless steel, and aluminum. Niclosamide-coated surfaces exhibited potent in vitro activity against S. aureus, MRSA, and S. epidermidis. At niclosamide surface concentrations as low as 1.6 × 10 -2 μg mm -2 , the coatings prevented attachment of these bacteria. The coatings also cleared bacteria inoculated suspensions at niclosamide surface concentrations of 3.1 × 10 -2 μg mm -2 . Hemolysis was not observed at any of the antimicrobial coating concentrations tested. We report a facile, effective means of coating devices with niclosamide to both clear and prevent biofilm formation of common bacteria encountered in hospital-acquired and device-associated infections.

  10. Endophytic colonization of Vitis vinifera L. by Burkholderia phytofirmans strain PsJN: from the rhizosphere to inflorescence tissues.

    Science.gov (United States)

    Compant, Stéphane; Kaplan, Hervé; Sessitsch, Angela; Nowak, Jerzy; Ait Barka, Essaïd; Clément, Christophe

    2008-01-01

    The colonization pattern of Vitis vinifera L. by Burkholderia phytofirmans strain PsJN was determined using grapevine fruiting cuttings with emphasis on putative inflorescence colonization under nonsterile conditions. Two-week-old rooted plants harbouring flower bud initials, grown in nonsterile soil, were inoculated with PsJN:gfp2x. Plant colonization was subsequently monitored at various times after inoculation with plate counts and epifluorescence and/or confocal microscopy. Strain PsJN was chronologically detected on the root surfaces, in the endorhiza, inside grape inflorescence stalks, not inside preflower buds and flowers but rather as an endophyte inside young berries. Data demonstrated low endophytic populations of strain PsJN in inflorescence organs, i.e. grape stalks and immature berries with inconsistency among plants for bacterial colonization of inflorescences. Nevertheless, endophytic colonization of inflorescences by strain PsJN was substantial for some plants. Microscopic analysis revealed PsJN as a thriving endophyte in inflorescence organs after the colonization process. Strain PsJN was visualized colonizing the root surface, entering the endorhiza and spreading to grape inflorescence stalks, pedicels and then to immature berries through xylem vessels. In parallel to these observations, a natural microbial communities was also detected on and inside plants, demonstrating the colonization of grapevine by strain PsJN in the presence of other microorganisms.

  11. Antigen 43-mediated autotransporter display, a versatile bacterial cell surface presentation system

    DEFF Research Database (Denmark)

    Kjærgaard, Kristian; Hasman, Henrik; Schembri, Mark

    2002-01-01

    to the outer membrane and secretion through the cell envelope is contained within the protein itself. Ag43 consists of two subunits (alpha and beta), where the beta-subunit forms an integral outer membrane translocator to which the alpha-subunit is noncovalently attached. The simplicity of the Ag43 system...... makes it ideally suited as a surface display scaffold. Here we demonstrate that the Ag43 alpha-module can accommodate and display correctly folded inserts and has the ability to display entire functional protein domains, exemplified by the FimH lectin domain. The presence of heterologous cysteine...... bridges does not interfere with surface display, and Ag43 chimeras are correctly processed into alpha- and beta-modules, offering optional and easy release of the chimeric alpha-subunits. Furthermore, Ag43 can be displayed in many gram-negative bacteria. This feature is exploited for display of our...

  12. The osmolyte xylitol reduces the salt concentration of airway surface liquid and may enhance bacterial killing

    Science.gov (United States)

    Zabner, Joseph; Seiler, Michael P.; Launspach, Janice L.; Karp, Philip H.; Kearney, William R.; Look, Dwight C.; Smith, Jeffrey J.; Welsh, Michael J.

    2000-10-01

    The thin layer of airway surface liquid (ASL) contains antimicrobial substances that kill the small numbers of bacteria that are constantly being deposited in the lungs. An increase in ASL salt concentration inhibits the activity of airway antimicrobial factors and may partially explain the pathogenesis of cystic fibrosis (CF). We tested the hypothesis that an osmolyte with a low transepithelial permeability may lower the ASL salt concentration, thereby enhancing innate immunity. We found that the five-carbon sugar xylitol has a low transepithelial permeability, is poorly metabolized by several bacteria, and can lower the ASL salt concentration in both CF and non-CF airway epithelia in vitro. Furthermore, in a double-blind, randomized, crossover study, xylitol sprayed for 4 days into each nostril of normal volunteers significantly decreased the number of nasal coagulase-negative Staphylococcus compared with saline control. Xylitol may be of value in decreasing ASL salt concentration and enhancing the innate antimicrobial defense at the airway surface.

  13. Engineering bacterial surface displayed human norovirus capsid proteins: A novel system to explore interaction between norovirus and ligands

    Directory of Open Access Journals (Sweden)

    Mengya eNiu

    2015-12-01

    Full Text Available Human noroviruses (HuNoVs are major contributors to acute nonbacterial gastroenteritis outbreaks. Many aspects of HuNoVs are poorly understood due to both the current inability to culture HuNoVs, and the lack of efficient small animal models. Surrogates for HuNoVs, such as recombinant viral like particles (VLPs expressed in eukaryotic system or P particles expressed in prokaryotic system, have been used for studies in immunology and interaction between the virus and its receptors. However, it is difficult to use VLPs or P particles to collect or isolate potential ligands binding to these recombinant capsid proteins. In this study, a new strategy was used to collect HuNoVs binding ligands through the use of ice nucleation protein (INP to display recombinant capsid proteins of HuNoVs on bacterial surfaces. The viral protein-ligand complex could be easily separated by a low speed centrifugation step. This system was also used to explore interaction between recombinant capsid proteins of HuNoVs and their receptors. In this system, the VP1 capsid encoding gene (ORF2 and the protruding domain (P domain encoding gene (3’ terminal fragment of ORF2 of HuNoVs GI.1 and GII.4 were fused with 5’ terminal fragment of ice nucleation protein encoding gene (inaQn. The results demonstrated that the recombinant VP1 and P domains of HuNoVs were expressed and anchored on the surface of Escherichia coli BL21 cells after the bacteria were transformed with the corresponding plasmids. Both cell surface displayed VP1 and P domains could be recognized by HuNoVs specific antibodies and interact with the viral histo-blood group antigens receptors. In both cases, displayed P domains had better binding abilities than VP1. This new strategy of using displayed HuNoVs capsid proteins on the bacterial surface could be utilized to separate HuNoVs binding components from complex samples, to investigate interaction between the virus and its receptors, as well as to develop an

  14. Amperometric L-glutamate biosensor based on bacterial cell-surface displayed glutamate dehydrogenase

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Bo [Laboratory for Biosensing, Key Laboratory of Biofuels, and Shandong Provinicial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy & Bioprocess Technology, Chinese Academy of Sciences, 189 Songling Road, Qingdao 266101 (China); University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049 (China); Zhang, Shu [Laboratory for Biosensing, Key Laboratory of Biofuels, and Shandong Provinicial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy & Bioprocess Technology, Chinese Academy of Sciences, 189 Songling Road, Qingdao 266101 (China); Key Laboratory of Marine Chemistry Theory and Technology of Ministry of Education, Ocean University of China, 238 Songling Road, Qingdao 266100 (China); Lang, Qiaolin [Laboratory for Biosensing, Key Laboratory of Biofuels, and Shandong Provinicial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy & Bioprocess Technology, Chinese Academy of Sciences, 189 Songling Road, Qingdao 266101 (China); Song, Jianxia; Han, Lihui [Key Laboratory of Marine Chemistry Theory and Technology of Ministry of Education, Ocean University of China, 238 Songling Road, Qingdao 266100 (China); Liu, Aihua, E-mail: liuah@qibebt.ac.cn [Laboratory for Biosensing, Key Laboratory of Biofuels, and Shandong Provinicial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy & Bioprocess Technology, Chinese Academy of Sciences, 189 Songling Road, Qingdao 266101 (China); University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049 (China)

    2015-07-16

    Highlights: • E. coli surface-dispalyed Gldh exhibiting excellent enzyme activity and stability. • Sensitive amperometric biosensor for glutamate using Gldh-bacteria and MWNTs. • The glutamate biosensor exhibited high specificity and stability. - Abstract: A novel L-glutamate biosensor was fabricated using bacteria surface-displayed glutamate dehydrogenase (Gldh-bacteria). Here the cofactor NADP{sup +}-specific dependent Gldh was expressed on the surface of Escherichia coli using N-terminal region of ice nucleation protein (INP) as the anchoring motif. The cell fractionation assay and SDS-PAGE analysis indicated that the majority of INP-Gldh fusion proteins were located on the surface of cells. The biosensor was fabricated by successively casting polyethyleneimine (PEI)-dispersed multi-walled carbon nanotubes (MWNTs), Gldh-bacteria and Nafion onto the glassy carbon electrode (Nafion/Gldh-bacteria/PEI-MWNTs/GCE). The MWNTs could not only significantly lower the oxidation overpotential towards NAPDH, which was the product of NADP{sup +} involving in the oxidation of glutamate by Gldh, but also enhanced the current response. Under the optimized experimental conditions, the current–time curve of the Nafion/Gldh-bacteria/PEI-MWNTs/GCE was performed at +0.52 V (vs. SCE) by amperometry varying glutamate concentration. The current response was linear with glutamate concentration in two ranges (10 μM–1 mM and 2–10 mM). The low limit of detection was estimated to be 2 μM glutamate (S/N = 3). Moreover, the proposed biosensor is stable, specific, reproducible and simple, which can be applied to real samples detection.

  15. Preparation and surface functionalisation of poly(styrene maleimide) nanoparticles for bacterial detection

    CSIR Research Space (South Africa)

    Barnard, A

    2012-10-01

    Full Text Available .kashan.co.za] INTRODUCTION The detection of bacteria in water is essential for the prevention of water-borne disease outbreaks. Conventionally, culturing methods are used to detect bacteria in water, whereby the number of bacteria present in a sample is multiplied to a... to the particle surfaces for attachment of fluorescent markers and antibodies. Figure 1: Process diagram of proposed development method of nanoparticles for bacteria detection Particle characterisation was performed with transmission electron microscopy (TEM...

  16. Polyspecies biofilm formation on implant surfaces with different surface characteristics

    Directory of Open Access Journals (Sweden)

    Patrick R. SCHMIDLIN

    2013-01-01

    Full Text Available Objective To investigate the microbial adherence and colonization of a polyspecies biofilm on 7 differently processed titanium surfaces. Material and Methods Six-species biofilms were formed anaerobically on 5-mm-diameter sterilized, saliva-preconditioned titanium discs. Material surfaces used were either machined, stained, acid-etched or sandblasted/acid-etched (SLA. Samples of the latter two materials were also provided in a chemically modified form, with increased wettability characteristics. Surface roughness and contact angles of all materials were determined. The discs were then incubated anaerobically for up to 16.5 h. Initial microbial adherence was evaluated after 20 min incubation and further colonization after 2, 4, 8, and 16.5 h using non-selective and selective culture techniques. Results at different time points were compared using ANOVA and Scheffé post hoc analysis. Results The mean differences in microorganisms colonizing after the first 20 min were in a very narrow range (4.5 to 4.8 log CFU. At up to 16.5 h, the modified SLA surface exhibited the highest values for colonization (6.9±0.2 log CFU, p<0.05 but increasing growth was observed on all test surfaces over time. Discrepancies among bacterial strains on the differently crafted titanium surfaces were very similar to those described for total log CFU. F. nucleatum was below the detection limit on all surfaces after 4 h. Conclusion Within the limitations of this in vitro study, surface roughness had a moderate influence on biofilm formation, while wettability did not seem to influence biofilm formation under the experimental conditions described. The modified SLA surface showed the highest trend for bacterial colonization.

  17. Amperometric L-glutamate biosensor based on bacterial cell-surface displayed glutamate dehydrogenase.

    Science.gov (United States)

    Liang, Bo; Zhang, Shu; Lang, Qiaolin; Song, Jianxia; Han, Lihui; Liu, Aihua

    2015-07-16

    A novel L-glutamate biosensor was fabricated using bacteria surface-displayed glutamate dehydrogenase (Gldh-bacteria). Here the cofactor NADP(+)-specific dependent Gldh was expressed on the surface of Escherichia coli using N-terminal region of ice nucleation protein (INP) as the anchoring motif. The cell fractionation assay and SDS-PAGE analysis indicated that the majority of INP-Gldh fusion proteins were located on the surface of cells. The biosensor was fabricated by successively casting polyethyleneimine (PEI)-dispersed multi-walled carbon nanotubes (MWNTs), Gldh-bacteria and Nafion onto the glassy carbon electrode (Nafion/Gldh-bacteria/PEI-MWNTs/GCE). The MWNTs could not only significantly lower the oxidation overpotential towards NAPDH, which was the product of NADP(+) involving in the oxidation of glutamate by Gldh, but also enhanced the current response. Under the optimized experimental conditions, the current-time curve of the Nafion/Gldh-bacteria/PEI-MWNTs/GCE was performed at +0.52 V (vs. SCE) by amperometry varying glutamate concentration. The current response was linear with glutamate concentration in two ranges (10 μM-1 mM and 2-10 mM). The low limit of detection was estimated to be 2 μM glutamate (S/N=3). Moreover, the proposed biosensor is stable, specific, reproducible and simple, which can be applied to real samples detection. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. New methods for determination of microbial adherence and colonization to bio material surface pre and post-irradiation treatment in cancer patients

    International Nuclear Information System (INIS)

    Shehata, M.M.K.K.

    2007-01-01

    Biomaterials are being used with increasing frequency in medical fields in the saving of patients' lives and enhancing the quality of life for many others.Colonization of biomaterials by some pathogenic microorganisms depends on their ability to grow and adhere to the solid surface which then allows microorganisms to from bio films in which they are protected from host defense mechanisms and antimicrobial chemotherapy. Adherence and colonization followed by biofilm formation has been implicated as a potential virulence factor of some pathogenic strains responsible for catheter related infections in immuno-compromised cancer patients. Adherence assay and quantitation of bio films of microorganisms isolated and identified from catheter associated urinary tract infections from bladder cancer patients was performed by spectrophotometric method, hydrophobicities of some tested strains were also evaluated by adhesion to p-xylene, MICs of various antibiotics for isolated strains in conjunction with plasmid profiles and algD gene responsible for biofilm formation of selected strains were determined before and after in-vitro exposure to test dose of 24.14 Gy gamma radiation in studying the role of radiotherapy on the microorganisms and their virulence and also enable the design for new approaches to the prevention of serious microbial infections by interfering with adhesion process

  19. An ex vivo porcine nasal mucosa explants model to study MRSA colonization.

    Directory of Open Access Journals (Sweden)

    Pawel Tulinski

    Full Text Available Staphylococcus aureus is an opportunistic pathogen able to colonize the upper respiratory tract and skin surfaces in mammals. Methicillin-resistant S. aureus ST398 is prevalent in pigs in Europe and North America. However, the mechanism of successful pig colonization by MRSA ST398 is poorly understood. To study MRSA colonization in pigs, an ex vivo model consisting of porcine nasal mucosa explants cultured at an air-liquid interface was evaluated. In cultured mucosa explants from the surfaces of the ventral turbinates and septum of the pig nose no changes in cell morphology and viability were observed up to 72 h. MRSA colonization on the explants was evaluated followed for three MRSA ST398 isolates for 180 minutes. The explants were incubated with 3×10(8 CFU/ml in PBS for 2 h to allow bacteria to adhere to the explants surface. Next the explants were washed and in the first 30 minutes post adhering time, a decline in the number of CFU was observed for all MRSA. Subsequently, the isolates showed either: bacterial growth, no growth, or a further reduction in bacterial numbers. The MRSA were either localized as clusters between the cilia or as single bacteria on the cilia surface. No morphological changes in the epithelium layer were observed during the incubation with MRSA. We conclude that porcine nasal mucosa explants are a valuable ex vivo model to unravel the interaction of MRSA with nasal tissue.

  20. An ex vivo porcine nasal mucosa explants model to study MRSA colonization.

    Science.gov (United States)

    Tulinski, Pawel; Fluit, Ad C; van Putten, Jos P M; de Bruin, Alain; Glorieux, Sarah; Wagenaar, Jaap A; Duim, Birgitta

    2013-01-01

    Staphylococcus aureus is an opportunistic pathogen able to colonize the upper respiratory tract and skin surfaces in mammals. Methicillin-resistant S. aureus ST398 is prevalent in pigs in Europe and North America. However, the mechanism of successful pig colonization by MRSA ST398 is poorly understood. To study MRSA colonization in pigs, an ex vivo model consisting of porcine nasal mucosa explants cultured at an air-liquid interface was evaluated. In cultured mucosa explants from the surfaces of the ventral turbinates and septum of the pig nose no changes in cell morphology and viability were observed up to 72 h. MRSA colonization on the explants was evaluated followed for three MRSA ST398 isolates for 180 minutes. The explants were incubated with 3×10(8) CFU/ml in PBS for 2 h to allow bacteria to adhere to the explants surface. Next the explants were washed and in the first 30 minutes post adhering time, a decline in the number of CFU was observed for all MRSA. Subsequently, the isolates showed either: bacterial growth, no growth, or a further reduction in bacterial numbers. The MRSA were either localized as clusters between the cilia or as single bacteria on the cilia surface. No morphological changes in the epithelium layer were observed during the incubation with MRSA. We conclude that porcine nasal mucosa explants are a valuable ex vivo model to unravel the interaction of MRSA with nasal tissue.

  1. Sequential colonization of periodontal pathogens in induction of periodontal disease and atherosclerosis in LDLRnull mice.

    Science.gov (United States)

    Chukkapalli, Sasanka S; Easwaran, Meena; Rivera-Kweh, Mercedes F; Velsko, Irina M; Ambadapadi, Sriram; Dai, Jiayin; Larjava, Hannu; Lucas, Alexandra R; Kesavalu, Lakshmyya

    2017-01-01

    Periodontal disease (PD) and atherosclerotic vascular disease (ASVD) are both chronic inflammatory diseases with a polymicrobial etiology and have been epidemiologically associated. The purpose is to examine whether periodontal bacteria that infect the periodontium can also infect vascular tissues and enhance pre-existing early aortic atherosclerotic lesions in LDLRnull mice. Mice were orally infected with intermediate bacterial colonizer Fusobacterium nucleatum for the first 12 weeks followed by late bacterial colonizers (Porphyromonas gingivalis, Treponema denticola and Tannerella forsythia) for the remaining 12 weeks mimicking the human oral microbiota ecological colonization. Genomic DNA from all four bacterial was detected in gingival plaque by PCR, consistently demonstrating infection of mouse gingival surfaces. Infected mice had significant levels of IgG and IgM antibodies, alveolar bone resorption, and showed apical migration of junctional epithelium revealing the induction of PD. These results support the ability of oral bacteria to cause PD in mice. Detection of bacterial genomic DNA in systemic organs indicates hematogenous dissemination from the gingival pockets. Bacterial infection did not alter serum lipid fractions or serum amyloid A levels and did not induce aortic atherosclerotic plaque. This is the first study examining the causal role of periodontal bacteria in induction of ASVD in LDLRnull mice. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Colon neoplasm

    International Nuclear Information System (INIS)

    Kimura F, K.

    1991-01-01

    The main aspects of colon neoplasms are described, including several factors that predispose the disease, the occurrence, the main biomedical radiography and the evaluation after the surgery. (C.G.C.)

  3. Methods for dynamic investigations of surface-attached in vitro bacterial and fungal biofilms

    DEFF Research Database (Denmark)

    Sternberg, Claus; Bjarnsholt, Thomas; Shirtliff, Mark

    2014-01-01

    Three dynamic models for the investigation of in vitro biofilm formation are described in this chapter. In the 6-well plate assay presented here, the placing of the plate on a rotating platform provides shear, thereby making the system dynamic with respect to the static microtiter assay.The second...... reported model, especially suitable for harvesting high amounts of cells for transcriptomic or proteomic investigations, is based on numerous glass beads placed in a flask incubated with shaking on a rotating platform, thus increasing the surface area for biofilm formation. Finally, the flow-cell system...

  4. Bacterial production of sunscreen pigments increase arid land soil surface temperature

    Science.gov (United States)

    Couradeau, Estelle; Karaoz, Ulas; Lim, HsiaoChien; Nunes da Rocha, Ulisses; Northern, Trent; Brodie, Eoin; Garcia-Pichel, Ferran

    2015-04-01

    Biological Soil Crusts (BSCs) are desert top soils formations built by complex microbial communities and dominated by the filamentous cyanobacterium Microcoleus sp. BSCs cover extensive desert areas where they correspond to millimeters size mantles responsible of soil stability and fertility. Despite their ecological importance, little is known about how these communities will endure climate change. It has been shown in North America that different species of Microcoleus showed distinct temperature preferences and that their continental biogeography may be susceptible to small changes in temperature with unknown consequences for the ecosystem function. Using a combination of physical, biochemical and microbiological analyses to characterize a successional gradient of crust maturity from light to dark BSCs (Moab, Utah) we found that the concentration of scytonemin (a cyanobacterial sunscreen pigment) increased with crust maturity. We also confirmed that scytonemin was by far the major pigment responsible of light absorption in the visible spectrum in BSCs, and is then responsible of the darkening of the BSCs (i.e decrease of albedo) with maturity. We measured the surface temperature and albedo and found, as predicted, a negative linear relationship between these two parameters. The decrease in albedo across the gradient of crust maturity corresponded to an increase in surface temperature up to 10° C. Upon investigation of microbial community composition using SSU rRNA gene analysis, we demonstrate that warmer crust surface temperatures (decreased albedo) are associated with a replacement of the dominant cyanobacterium; the thermosensitive Microcoleus sp. being replaced by a thermotolerant Microcoleus sp. in darker BSCs. This study supports at the local scale a finding previously made at the continental scale, but also sheds light on the importance of scytonemin as a significant warmer of soils with important consequences for BSC composition and function. Based on

  5. Rapid identification of bacterial resistance to Ciprofloxacin using surface-enhanced Raman spectroscopy

    Science.gov (United States)

    Kastanos, Evdokia; Hadjigeorgiou, Katerina; Pitris, Costas

    2014-02-01

    Due to its effectiveness and broad coverage, Ciprofloxacin is the fifth most prescribed antibiotic in the US. As current methods of infection diagnosis and antibiotic sensitivity testing (i.e. an antibiogram) are very time consuming, physicians prescribe ciprofloxacin before obtaining antibiogram results. In order to avoid increasing resistance to the antibiotic, a method was developed to provide both a rapid diagnosis and the sensitivity to the antibiotic. Using Surface Enhanced Raman Spectroscopy, an antibiogram was obtained after exposing the bacteria to Ciprofloxacin for just two hours. Spectral analysis revealed clear separation between sensitive and resistant bacteria and could also offer some inside into the mechanisms of resistance.

  6. Biodegradation of bispyribac sodium by a novel bacterial consortium BDAM: Optimization of degradation conditions using response surface methodology.

    Science.gov (United States)

    Ahmad, Fiaz; Anwar, Samina; Firdous, Sadiqa; Da-Chuan, Yin; Iqbal, Samina

    2018-05-05

    Bispyribac sodium (BS), is a selective, systemic and post emergent herbicide used to eradicate grasses and broad leaf weeds. Extensive use of this herbicide has engendered serious environmental concerns. Hence it is important to develop strategies for bioremediation of BS in a cost effective and environment friendly way. In this study a bacterial consortium named BDAM, comprising three novel isolates Achromobacter xylosoxidans (BD1), Achromobacter pulmonis (BA2), and Ochrobactrum intermedium (BM2), was developed by virtue of its potential for degradation of BS. Different culture conditions (temperature, pH and inoculum size) were optimized for degradation of BS by the consortium BDAM and the mutual interactions of these parameters were analysed using a 2 3 full factorial central composite design (CCD) based on Response Surface Methodology (RSM). The optimal values for temperature, pH and inoculum size were found to be 40 °C, 8 and 0.4 g/L respectively to achieve maximum degradation of BS (85.6%). Moreover, the interactive effects of these parameters were investigated using three dimensional surface plots in terms of maximum fitness function. Importantly, it was concluded that the newly developed consortium is a potential candidate for biodegradation of BS in a safe, cost-effective and environmentally friendly manner. Copyright © 2017. Published by Elsevier B.V.

  7. Spatial Homogeneity of Bacterial Communities Associated with the Surface Mucus Layer of the Reef-Building Coral Acropora palmata.

    Directory of Open Access Journals (Sweden)

    Dustin W Kemp

    Full Text Available Coral surface mucus layer (SML microbiota are critical components of the coral holobiont and play important roles in nutrient cycling and defense against pathogens. We sequenced 16S rRNA amplicons to examine the structure of the SML microbiome within and between colonies of the threatened Caribbean reef-building coral Acropora palmata in the Florida Keys. Samples were taken from three spatially distinct colony regions--uppermost (high irradiance, underside (low irradiance, and the colony base--representing microhabitats that vary in irradiance and water flow. Phylogenetic diversity (PD values of coral SML bacteria communities were greater than surrounding seawater and lower than adjacent sediment. Bacterial diversity and community composition was consistent among the three microhabitats. Cyanobacteria, Bacteroidetes, Alphaproteobacteria, and Proteobacteria, respectively were the most abundant phyla represented in the samples. This is the first time spatial variability of the surface mucus layer of A. palmata has been studied. Homogeneity in the microbiome of A. palmata contrasts with SML heterogeneity found in other Caribbean corals. These findings suggest that, during non-stressful conditions, host regulation of SML microbiota may override diverse physiochemical influences induced by the topographical complexity of A. palmata. Documenting the spatial distribution of SML microbes is essential to understanding the functional roles these microorganisms play in coral health and adaptability to environmental perturbations.

  8. Spatial Homogeneity of Bacterial Communities Associated with the Surface Mucus Layer of the Reef-Building Coral Acropora palmata.

    Science.gov (United States)

    Kemp, Dustin W; Rivers, Adam R; Kemp, Keri M; Lipp, Erin K; Porter, James W; Wares, John P

    2015-01-01

    Coral surface mucus layer (SML) microbiota are critical components of the coral holobiont and play important roles in nutrient cycling and defense against pathogens. We sequenced 16S rRNA amplicons to examine the structure of the SML microbiome within and between colonies of the threatened Caribbean reef-building coral Acropora palmata in the Florida Keys. Samples were taken from three spatially distinct colony regions--uppermost (high irradiance), underside (low irradiance), and the colony base--representing microhabitats that vary in irradiance and water flow. Phylogenetic diversity (PD) values of coral SML bacteria communities were greater than surrounding seawater and lower than adjacent sediment. Bacterial diversity and community composition was consistent among the three microhabitats. Cyanobacteria, Bacteroidetes, Alphaproteobacteria, and Proteobacteria, respectively were the most abundant phyla represented in the samples. This is the first time spatial variability of the surface mucus layer of A. palmata has been studied. Homogeneity in the microbiome of A. palmata contrasts with SML heterogeneity found in other Caribbean corals. These findings suggest that, during non-stressful conditions, host regulation of SML microbiota may override diverse physiochemical influences induced by the topographical complexity of A. palmata. Documenting the spatial distribution of SML microbes is essential to understanding the functional roles these microorganisms play in coral health and adaptability to environmental perturbations.

  9. Use of Response Surface Methodology to Optimize Culture Conditions for Hydrogen Production by an Anaerobic Bacterial Strain from Soluble Starch

    Science.gov (United States)

    Kieu, Hoa Thi Quynh; Nguyen, Yen Thi; Dang, Yen Thi; Nguyen, Binh Thanh

    2016-05-01

    Biohydrogen is a clean source of energy that produces no harmful byproducts during combustion, being a potential sustainable energy carrier for the future. Therefore, biohydrogen produced by anaerobic bacteria via dark fermentation has attracted attention worldwide as a renewable energy source. However, the hydrogen production capability of these bacteria depends on major factors such as substrate, iron-containing hydrogenase, reduction agent, pH, and temperature. In this study, the response surface methodology (RSM) with central composite design (CCD) was employed to improve the hydrogen production by an anaerobic bacterial strain isolated from animal waste in Phu Linh, Soc Son, Vietnam (PL strain). The hydrogen production process was investigated as a function of three critical factors: soluble starch concentration (8 g L-1 to 12 g L-1), ferrous iron concentration (100 mg L-1 to 200 mg L-1), and l-cysteine concentration (300 mg L-1 to 500 mg L-1). RSM analysis showed that all three factors significantly influenced hydrogen production. Among them, the ferrous iron concentration presented the greatest influence. The optimum hydrogen concentration of 1030 mL L-1 medium was obtained with 10 g L-1 soluble starch, 150 mg L-1 ferrous iron, and 400 mg L-1 l-cysteine after 48 h of anaerobic fermentation. The hydrogen concentration produced by the PL strain was doubled after using RSM. The obtained results indicate that RSM with CCD can be used as a technique to optimize culture conditions for enhancement of hydrogen production by the selected anaerobic bacterial strain. Hydrogen production from low-cost organic substrates such as soluble starch using anaerobic fermentation methods may be one of the most promising approaches.

  10. Bacterial vs. fungal spore resistance to peroxygen biocide on inanimate surfaces

    Directory of Open Access Journals (Sweden)

    Mostafa Essam Eissa

    2014-12-01

    Full Text Available A sporicidal agent formula based on a mixture of peroxyacetic acid and hydrogen peroxide was assessed for its efficacy on a representative sample of vinyl surface material. Vinyl is the construction material of wall and floor lining in pharmaceutical plants. The experimental manipulations; applied herein, simulated the actual biocidal agent preparation and were carried out using USP purified water, test temperature was 20–25 °C, RH% was 40–60% and pH was 3.08 and 2.86 for 1% and 2% (v/v respectively. Following the selection of the optimum method of antimicrobial activity neutralization, two disinfectant concentrations were examined for their sporicidal activity. The results of carrier test revealed that the disinfectant concentration (2% (v/v was significantly effective as a sporicidal agent after 5 and 10 min for Aspergillus brasiliensis and Bacillus subtilis subsp. spizizenii, respectively, while the concentration of 1% (v/v did not achieve even one logarithmic reduction after 20 min. The agent was able to achieve more than 100 times reduction from the initial bioburden on the surfaces when used in the concentration of 2% (v/v after 10 min of contact time. The ideal kinetics of microbial death usually follows 2 parts (by averaging the responses with time for the 3 replicates: initial slow rate of death followed by higher rate. The initial sigmoidal part was only observed with B. subtilis upon exposure to 2% (v/v sporicidal agent. Elimination time for B. subtilis spores was 15 min which was about double the time required for eradication of A. brasiliensis.

  11. Bacterial Enhancement of Vinyl Fouling by Algae

    OpenAIRE

    Holmes, Paul E.

    1986-01-01

    The role of bacteria in the development of algae on low-density vinyl was investigated. Unidentified bacterial contaminants in unialgal stock cultures of Phormidium faveolarum and Pleurochloris pyrenoidosa enhanced, by 1 to 2 orders of magnitude, colonization of vinyl by these algae, as determined by epifluorescence microscopy counts and chlorophyll a in extracts of colonized vinyl. Colonization by bacteria always preceded that by algae. Scanning electron microscopy of the colonized Phormidiu...

  12. A Method for Quantification of Epithelium Colonization Capacity by Pathogenic Bacteria

    DEFF Research Database (Denmark)

    Micha Pedersen, Rune; Grønnemose, Rasmus Birkholm; Stærk, Kristian

    2018-01-01

    the bloodstream, effective dissemination again requires that bacteria in the blood, reestablish contact to distant endothelium sites and form secondary site foci. The infectious potential of bacteria is therefore closely linked to their ability to adhere to, colonize, and invade epithelial and endothelial...... of retained bacteria by agar plating. This approach is fast and straightforward, but yields only a rough estimate of the adhesive properties of the bacteria upon contact, and little information on the ability of the bacterium to colonize these surfaces under relevant physiological conditions. Here, we present...... a method in which epithelia/endothelia are simulated by flow chamber-grown human cell layers, and infection is induced by seeding of pathogenic bacteria on these surfaces under conditions that simulate the physiological microenvironment. Quantification of bacterial adhesion and colonization of the cell...

  13. Structure and chemistry of bacterially populated acidic microenvironments found on naturally colonized and weathered circumneutral pH unsaturated waste rock from the Antamina Mine, Peru

    Science.gov (United States)

    Dockrey, J. W.; Mayer, K. U.; Beckie, R. D.; Southam, G.

    2009-12-01

    The microbial community present in geochemically well characterized field cells and experimental waste rock piles at the Antamina Mine, were examined using electron microscopy, culture dependent, and culture independent techniques. Relatively large populations of up to 10^8 bacteria per gram were found, despite the young age of the waste rock (1.5 years). Most samples were at alkaline pH and dominated by bacteria capable of neutral pH thiosulfate oxidation. One sample from a field cell producing drainage at a pH of 6.5 was dominated by acidophilic bacteria capable of Fe^2+ and S^0 oxidation. A weathered massive sulfide from this sample was thoroughly examined using a field emission gun scanning electron microscope equipped with a focused ion beam (FE-SEM-FIB). Bacteria were abundant as monolayer and agglomerate biofilms upon and within a porous schwertmannite precipitate, while no bacteria were found directly attached to clean sulfide surfaces. Pitting of pyrrhotite was observed beneath the microbially inhabited schwertmannite, while no pitting was observed in adjacent clean pyrrhotite surfaces indicating greater oxidation of the pyrrhotite surface beneath the schwertmannite. Some waste rock that has been exposed to natural surface weathering conditions for more than twice the amount of time, possessed larger total populations of bacteria, but did not support significant populations of acidophiles, suggesting a succession from neutrophiles to acidophiles takes place prior to the development of acid mine drainage. The development of the porous iron oxide film may be prerequisite for acidophilic bacteria to flourish, creating acidic microenvironments within a neutral bulk, ambient pH mine waste.

  14. Strategies to improve the surface plasmon resonance-based immmunodetection of bacterial cells

    International Nuclear Information System (INIS)

    Charlermroj, Ratthaphol; Karoonuthaisiri, Nitsara; Gajanandana, Oraprapai; Himananto, Orawan; Oplatowska, Michalina; Grant, Irene R.; Elliott, Christopher T.

    2013-01-01

    We have made a comparison of (a) different surface chemistries of SPR sensor chips (such as carboxymethylated dextran and carboxymethylated C1) and (b) of different assay formats (direct, sandwich and subtractive immunoassay) in order to improve the sensitivity of the determination of the model bacteria Acidovorax avenae subsp. citrulli (Aac). The use of the carboxymethylated sensor chip C1 resulted in a better sensitivity than that of carboxymethylated dextran CM5 in all the assay formats. The direct assay format, in turn, exhibits the best sensitivity. Thus, the combination of a carboxymethylated sensor chip C1 with the direct assay format resulted in the highest sensitivity for Aac, with a limit of detection of 1.6 × 10 6 CFU mL -1 . This SPR immunosensor was applied to the detection of Aac in watermelon leaf extracts spiked with the bacteria, and the lower LOD is 2.2 × 10 7 CFU mL −1 . (author)

  15. The Association of Anisakiasis in the Ascending Colon with Sigmoid Colon Cancer: CT Colonography Findings

    International Nuclear Information System (INIS)

    Yoo, Hye Jin; Kim, Se Hyung; Lee, Jeong Min; Kim, Min A; Han, Joon Koo; Choi, Byung Ihn

    2008-01-01

    The association of anisakiasis of the colon with colon cancer is rare and difficult to diagnose. Only one case of this type has been reported to date. In this study, we report a case of synchronous colon cancer and colonic anisakiasis. A 50- year-old woman was admitted for abdominal pain, and a volume-rendered surface- shaded image of CT colonography (CTC) revealed a concentric narrowing in the sigmoid colon and a segmental fold thickening in the ascending colon. A total colectomy was performed and the diagnosis of synchronous sigmoid colon cancer and anisakiasis of the ascending colon was confirmed. This case is the first reported visualization of synchronous colon cancer and colonic anisakiasis on a CTC

  16. Colonic urticaria pattern due to early ischemia

    Energy Technology Data Exchange (ETDEWEB)

    Greenberg, H.M.; Goldberg, H.I.; Axel, L.

    1981-05-15

    The unusual radiographic pattern of bleb-like mounds on the surface of the colon mucosa, previously described as colonic urticaria, was seen in 3 patients in whom no allergic state was present. This urticaria-like pattern was due to colonic distention in all 3, and represented only submucosal edema on the gross and microscopic specimens. We hypothesize that this pattern is due to early changes of ischemia caused by colon distention.

  17. Escherichia coli Nissle 1917 bacterial ghosts retain crucial surface properties and express chlamydial antigen: an imaging study of a delivery system for the ocular surface.

    Science.gov (United States)

    Montanaro, Jacqueline; Inic-Kanada, Aleksandra; Ladurner, Angela; Stein, Elisabeth; Belij, Sandra; Bintner, Nora; Schlacher, Simone; Schuerer, Nadine; Mayr, Ulrike Beate; Lubitz, Werner; Leisch, Nikolaus; Barisani-Asenbauer, Talin

    2015-01-01

    To target chronic inflammatory ocular surface diseases, a drug delivery platform is needed that is safe, possesses immunomodulatory properties, and can be used either for drug delivery, or as a foreign antigen carrier. A new therapeutic approach that we have previously proposed uses nonliving bacterial ghosts (BGs) as a carrier-delivery system which can be engineered to carry foreign antigens and/or be loaded with therapeutic drugs. The parent strain chosen for development of our BG delivery system is the probiotic Escherichia coli strain Nissle 1917 (EcN), whose intrinsic properties trigger the innate immune system with the flagella and fimbriae used to attach and stimulate epithelial cells. In previous studies, we have shown that EcN BGs are safe for the ocular surface route, but evidence that EcN BGs retain flagella and fimbriae after transformation, has never been visually confirmed. In this study, we used different visualization techniques to determine whether flagella and fimbriae are retained on EcN BGs engineered either for drug delivery or as a foreign antigen carrier. We have also shown by immunoelectron microscopy that EcN retains two foreign antigens after processing to become EcN BGs. Furthermore, we demonstrated that BGs derived from EcN and expressing a foreign antigen attachment to conjunctival epithelial cells in vitro without causing reduced cell viability. These results are an important step in constructing a delivery system based on a nonliving probiotic that is suitable for use in ocular surface diseases pairing immunomodulation and targeted delivery.

  18. Investigating bacterial growth in surgical theatres: establishing the effect of laminar airflow on bacterial growth on plastic, metal and wood surfaces.

    Science.gov (United States)

    Da Costa, Alex Rodrigues; Kothari, Ami; Bannister, Gordon C; Blom, Ashley W

    2008-07-01

    Infection is a devastating complication of surgery. Intra-operative wound contamination is a common cause of infection. A number of measures have been effective in reducing wound contamination. One such measure is laminar flow. Controversy exists as to whether it is safe to keep open instruments and implants outside the laminar flow. This study compares bacterial contamination of wood, plastic and stainless steel within and outside the laminar flow. Identically shaped and sized tiles were left for 90 min within and outside the laminar flow and then cultured for bacterial growth. A third of metal and plastic tiles were contaminated, but only 10% of wooden tiles, suggesting that wood is a more hostile environment for bacteria. There was no difference in contamination between tiles placed inside and those placed outside the laminar flow. This study suggests that placing instruments and implants outside the laminar flow is a safe practice.

  19. Bacterial biodiversity in deep-sea sediments from two regions of contrasting surface water productivity near the Crozet Islands, Southern Ocean

    Science.gov (United States)

    Jamieson, R. E.; Heywood, J. L.; Rogers, A. D.; Billett, D. S. M.; Pearce, D. A.

    2013-05-01

    The relationship between surface-derived particulate organic matter (POM) and deep-sea sediment bacterial abundance, community structure and composition was investigated in two different sediment layers from two zones of contrasting surface water productivity in the southern Indian Ocean. Bacterial sediment communities from high chlorophyll (HC) and low chlorophyll (LC) sites were characterized and compared using direct counts, clone library construction, denaturing gradient gel electrophoresis (DGGE) and fluorescence in situ hybridization (FISH). Of the 1566 bacterial clones generated from the sediment communities, 1010 matched published 16S rDNA sequences at ≥97% identity. A comparison of surface sediment clone libraries showed that at least one third of all identified operational taxonomic units (OTUs) were common to both HC and LC sites. DGGE community profiles were consistent (82% similar) and evenness of the major phylogenetic groups was 96% similar between surface sediment communities, where gamma- and alpha-Proteobacteria were dominant. Sediment communities shared similarly high biodiversity, while species richness was marginally higher at the LC site. Intra-site shifts in bacterial abundance and composition were observed with increasing sediment depth. Despite the differences in organic matter input between sites, the consistency observed between HC and LC sediment communities pointed to (1) the extent of remineralisation by mega and meio-fauna as a potential factor affecting the quantity and quality of POM available to sediment bacteria, (2) sampling during the early 'nutrient assimilation phase' of the bacterial response to freshly deposited POM or (3) that the action of bacteria in the water column could affect the quantity and quality of POM available to sediment bacteria. Although factors other than these may explain the observed similarities, this first comparison of such deep-sea sediment communities in relation to surface-derived productivity may

  20. Preparation of PEI-coated bacterial biosorbent in water solution: optimization of manufacturing conditions using response surface methodology.

    Science.gov (United States)

    Mao, Juan; Kwak, In-Seob; Sathishkumar, Muthuswamy; Sneha, Krishnamurthy; Yun, Yeoung-Sang

    2011-01-01

    The aim of this study is to optimize preparation method of polyethyleneimine (PEI)-coated bacterial biosorbent in water as reaction media using fermentation waste biomass of Corynebacterium glutamicum as a raw material. The fermentation waste biomass of C. glutamicum and Reactive Red 4 were used as model raw bacterium and pollutant. Major factors affecting the performance of PEI-coated biosorbent were the amounts of polymer (PEI) and cross-linker glutaraldehyde (GA). These factors were optimized through response surface methodology (RSM) with two-level-two-factor (2(2)) full factorial central composite design. As a result, the optimum conditions were found to be 4.29 g of PEI and 0.15 mL of GA, with 10 g of the biomass, where the sorption capacity was enhanced 4.52-fold compared to that of the raw biomass. Therefore, this simple, cost-effective, and water-based method could be a useful modification tool for the development of a high performance biosorbent for removing anionic pollutants. Copyright © 2010 Elsevier Ltd. All rights reserved.

  1. Classification of bacterial samples as negative or positive for a UTI and antibiogram using surface enhanced Raman spectroscopy

    Science.gov (United States)

    Kastanos, Evdokia; Hadjigeorgiou, Katerina; Kyriakides, Alexandros; Pitris, Costas

    2011-03-01

    Urinary tract infection (UTI) diagnosis requires an overnight culture to identify a sample as positive or negative for a UTI. Additional cultures are required to identify the pathogen responsible for the infection and to test its sensitivity to antibiotics. A rise in ineffective treatments, chronic infections, rising health care costs and antibiotic resistance are some of the consequences of this prolonged waiting period of UTI diagnosis. In this work, Surface Enhanced Raman Spectroscopy (SERS) is used for classifying bacterial samples as positive or negative for UTI. SERS spectra of serial dilutions of E.coli bacteria, isolated from a urine culture, were classified as positive (105-108 cells/ml) or negative (103-104 cells/ml) for UTI after mixing samples with gold nanoparticles. A leave-one-out cross validation was performed using the first two principal components resulting in the correct classification of 82% of all samples. Sensitivity of classification was 88% and specificity was 67%. Antibiotic sensitivity testing was also done using SERS spectra of various species of gram negative bacteria collected 4 hours after exposure to antibiotics. Spectral analysis revealed clear separation between the spectra of samples exposed to ciprofloxacin (sensitive) and amoxicillin (resistant). This study can become the basis for identifying urine samples as positive or negative for a UTI and determining their antibiogram without requiring an overnight culture.

  2. Effect of UV-photofunctionalization on oral bacterial attachment and biofilm formation to titanium implant material.

    Science.gov (United States)

    de Avila, Erica Dorigatti; Lima, Bruno P; Sekiya, Takeo; Torii, Yasuyoshi; Ogawa, Takahiro; Shi, Wenyuan; Lux, Renate

    2015-10-01

    Bacterial biofilm infections remain prevalent reasons for implant failure. Dental implant placement occurs in the oral environment, which harbors a plethora of biofilm-forming bacteria. Due to its trans-mucosal placement, part of the implant structure is exposed to oral cavity and there is no effective measure to prevent bacterial attachment to implant materials. Here, we demonstrated that UV treatment of titanium immediately prior to use (photofunctionalization) affects the ability of human polymicrobial oral biofilm communities to colonize in the presence of salivary and blood components. UV-treatment of machined titanium transformed the surface from hydrophobic to superhydrophilic. UV-treated surfaces exhibited a significant reduction in bacterial attachment as well as subsequent biofilm formation compared to untreated ones, even though overall bacterial viability was not affected. The function of reducing bacterial colonization was maintained on UV-treated titanium that had been stored in a liquid environment before use. Denaturing gradient gel-electrophoresis (DGGE) and DNA sequencing analyses revealed that while bacterial community profiles appeared different between UV-treated and untreated titanium in the initial attachment phase, this difference vanished as biofilm formation progressed. Our findings confirm that UV-photofunctionalization of titanium has a strong potential to improve outcome of implant placement by creating and maintaining antimicrobial surfaces. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Effect of UV-photofunctionalization on Oral Bacterial Attachment and Biofilm Formation to Titanium Implant Material

    Science.gov (United States)

    de Avila, Erica Dorigatti; Lima, Bruno P.; Sekiya, Takeo; Torii, Yasuyoshi; Ogawa, Takahiro; Shi, Wenyuan; Lux, Renate

    2015-01-01

    Bacterial biofilm infections remain prevalent reasons for implant failure. Dental implant placement occurs in the oral environment, which harbors a plethora of biofilm-forming bacteria. Due to its trans-mucosal placement, part of the implant structure is exposed to oral cavity and there is no effective measure to prevent bacterial attachment to implant materials. Here, we demonstrated that UV treatment of titanium immediately prior to use (photofunctionalization) affects the ability of human polymicrobial oral biofilm communities to colonize in the presence of salivary and blood components. UV-treatment of machined titanium transformed the surface from hydrophobic to superhydrophilic. UV-treated surfaces exhibited a significant reduction in bacterial attachment as well as subsequent biofilm formation compared to untreated ones, even though overall bacterial viability was not affected. The function of reducing bacterial colonization was maintained on UV-treated titanium that had been stored in a liquid environment before use. Denaturing gradient gel-electrophoresis (DGGE) and DNA sequencing analyses revealed that while bacterial community profiles appeared different between UV-treated and untreated titanium in the initial attachment phase, this difference vanished as biofilm formation progressed. Our findings confirm that UV-photofunctionalization of titanium has a strong potential to improve outcome of implant placement by creating and maintaining antimicrobial surfaces. PMID:26210175

  4. Learning about Colon Cancer

    Science.gov (United States)

    ... What do we know about heredity and colon cancer? Colon cancer, a malignant tumor of the large intestine, ... page Additional Resources for Information on Hereditary Colon Cancer Colon and Rectal Cancer Information [cancer.gov] The most ...

  5. Escherichia coli Nissle 1917 bacterial ghosts retain crucial surface properties and express chlamydial antigen: an imaging study of a delivery system for the ocular surface

    Directory of Open Access Journals (Sweden)

    Montanaro J

    2015-07-01

    Full Text Available Jacqueline Montanaro,1 Aleksandra Inic-Kanada,1 Angela Ladurner,1 Elisabeth Stein,1 Sandra Belij,1 Nora Bintner,1 Simone Schlacher,1 Nadine Schuerer,1 Ulrike Beate Mayr,2 Werner Lubitz,2 Nikolaus Leisch,3 Talin Barisani-Asenbauer11Laura Bassi Centres of Expertise, OCUVAC – Centre of Ocular Inflammation and Infection, Centre for Pathophysiology, Infectiology, and Immunology, Medical University of Vienna, Vienna, Austria; 2BIRD-C GmbH & Co KG, Kritzendorf, Austria; 3Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, AustriaAbstract: To target chronic inflammatory ocular surface diseases, a drug delivery platform is needed that is safe, possesses immunomodulatory properties, and can be used either for drug delivery, or as a foreign antigen carrier. A new therapeutic approach that we have previously proposed uses nonliving bacterial ghosts (BGs as a carrier-delivery system which can be engineered to carry foreign antigens and/or be loaded with therapeutic drugs. The parent strain chosen for development of our BG delivery system is the probiotic Escherichia coli strain Nissle 1917 (EcN, whose intrinsic properties trigger the innate immune system with the flagella and fimbriae used to attach and stimulate epithelial cells. In previous studies, we have shown that EcN BGs are safe for the ocular surface route, but evidence that EcN BGs retain flagella and fimbriae after transformation, has never been visually confirmed. In this study, we used different visualization techniques to determine whether flagella and fimbriae are retained on EcN BGs engineered either for drug delivery or as a foreign antigen carrier. We have also shown by immunoelectron microscopy that EcN retains two foreign antigens after processing to become EcN BGs. Furthermore, we demonstrated that BGs derived from EcN and expressing a foreign antigen attachment to conjunctival epithelial cells in vitro without causing reduced cell viability. These results

  6. Acquisition of C1 inhibitor by Bordetella pertussis virulence associated gene 8 results in C2 and C4 consumption away from the bacterial surface

    Science.gov (United States)

    Hovingh, Elise S.; Kuipers, Betsy; Pinelli, Elena; Rooijakkers, Suzan H. M.

    2017-01-01

    Whooping cough, or pertussis, is a contagious disease of the respiratory tract that is re-emerging worldwide despite high vaccination coverage. The causative agent of this disease is the Gram-negative Bordetella pertussis. Knowledge on complement evasion strategies of this pathogen is limited. However, this is of great importance for future vaccine development as it has become apparent that a novel pertussis vaccine is needed. Here, we unravel the effect of Virulence associated gene 8 (Vag8) of B. pertussis on the human complement system at the molecular level. We show that both recombinant and endogenously secreted Vag8 inhibit complement deposition on the bacterial surface at the level of C4b. We reveal that Vag8 binding to human C1-inhibitor (C1-inh) interferes with the binding of C1-inh to C1s, C1r and MASP-2, resulting in the release of active proteases that subsequently cleave C2 and C4 away from the bacterial surface. We demonstrate that the depletion of these complement components in the bacterial surrounding and subsequent decreased deposition on B. pertussis leads to less complement-mediated bacterial killing. Vag8 is the first protein described that specifically prevents C1s, C1r and MASP-2 binding to C1-inh and thereby mediates complement consumption away from the bacterial surface. Unravelling the mechanism of this unique complement evasion strategy of B. pertussis is one of the first steps towards understanding the interactions between the first line of defense complement and B. pertussis. PMID:28742139

  7. The Efficacy of Umbelliferone, Arbutin, and N-Acetylcysteine to Prevent Microbial Colonization and Biofilm Development on Urinary Catheter Surface: Results from a Preliminary Study

    Directory of Open Access Journals (Sweden)

    Tommaso Cai

    2016-01-01

    Full Text Available We evaluated, in a preliminary study, the efficacy of umbelliferone, arbutin, and N-acetylcysteine to inhibit biofilm formation on urinary catheter. We used 20 urinary catheters: 5 catheters were incubated with Enterococcus faecalis (control group; 5 catheters were incubated with E. faecalis in presence of umbelliferone (150 mg, arbutin (60 mg, and N-acetylcysteine (150 mg (group 1; 5 catheters were incubated with E. faecalis in presence of umbelliferone (150 mg, arbutin (60 mg, and N-acetylcysteine (400 mg (group 2; and 5 catheters were incubated with E. faecalis in presence of umbelliferone (300 mg, arbutin (60 mg, and N-acetylcysteine (150 mg (group 3. After 72 hours, planktonic microbial growth and microorganisms on catheter surface were assessed. In the control group, we found a planktonic load of ≥105 CFU/mL in the inoculation medium and retrieved 3.69 × 106 CFU/cm from the sessile cells adherent to the catheter surface. A significantly lower amount in planktonic (p<0.001 and sessile (p=0.004 bacterial load was found in group 3, showing <100 CFU/mL and 0.12 × 106 CFU/cm in the incubation medium and on the catheter surface, respectively. In groups 1 and 2, 1.67 × 106 CFU/cm and 1.77 × 106 CFU/cm were found on catheter surface. Our results document that umbelliferone, arbutin, and N-acetylcysteine are able to reduce E. faecalis biofilm development on the surface of urinary catheters.

  8. Analysis of bacterial contamination on surface of general radiography equipment and CT equipment in emergency room of radiology

    International Nuclear Information System (INIS)

    Hong, Dong Hee; KIm, Hyeong Gyun

    2016-01-01

    We aim to offer basic materials about infection management through conducting bacterial contamination test about general radiography equipment and CT equipment installed in ER of three general hospitals with 100 sickbeds or more located in Gyeongsangbuk-do Province, and suggest management plan. It had been conducted from 1st December 2015 to 31st December, and objects were general radiography equipment and CT equipment of emergency room located in Gyeongsangbuk-do Province. For general radiography equipment, sources were collected from 4 places such as upper side of control box which employees use most, upper side of exposure button, whole upper side of table which is touching part of patient's skin, upper side of stand bucky's grid, and where patients put their jaws on. For CT equipment, sources were collected from 3 places such as upper side of control box which radiography room employees use most, X-ray exposure button, whole upper side of table which is touching part of patient's skin, and gantry inner. Surface contamination strain found at general radiography equipment in emergency room of radiology are Providencia stuartii(25%), Stenotrophomonas maltophilia(18%), Enterobacter cloacae(8%), Pseudomonas species(8%), Staphylococcus epidermidis(8%), Gram negative bacilli(8%), and ungrown bacteria at incubator after 48 hours of incubation (67%) which is the biggest. Most bacteria were found at upper side of stand bucky-grid and stand bucky of radiology's general radiography equipment, and most sources of CT equipment were focused at patient table, which means it is contaminated by patients who have various diseases, and patients who have strains with decreased immunity may get severe diseases. Thus infection prevention should be made through 70% alcohol disinfection at both before test and after test

  9. Analysis of potential risks from the bacterial communities associated with air-contact surfaces from tilapia (Oreochromis niloticus) fish farming.

    Science.gov (United States)

    Grande Burgos, Maria Jose; Romero, Jose Luis; Pérez Pulido, Rubén; Cobo Molinos, Antonio; Gálvez, Antonio; Lucas, Rosario

    2018-01-01

    Tilapia farming is a promising growing sector in aquaculture. Yet, there are limited studies on microbiological risks associated to tilapia farms. The aim of the present study was to analyse the bacterial communities from solid surfaces in contact with air in a tilapia farm in order to evaluate the presence of bacteria potentially toxinogenic or pathogenic to humans or animals. Samples from a local tilapia farm (tank wall, aerator, water outlets, sink and floor) were analyzed by high throughput sequencing technology. Sequences were assigned to operational taxonomic units (OTUs). Proteobacteria was the main phylum represented in most samples (except for one). Cyanobacteria were a relevant phylum in the inner wall from the fattening tank and the wet floor by the pre-fattening tank. Bacteroidetes were the second phylum in relative abundance for samples from the larval rearing tank and the pre-fattening tank and one sample from the fattening tank. Fusobacteria showed highest relative abundances in samples from the larval rearing tank and pre-fattening tank. Other phyla (Verrucomicrobia, Actinobacteria, Firmicutes, Planktomycetes, Acidobacteria, Chloroflexi, Chlorobi, Gemmatiomonadetes or Fibrobacters) had lower relative abundances. A large fraction of the reads (ranging from 43.67% to 72.25%) were assigned to uncultured bacteria. Genus Acinetobacter (mainly A. calcoaceticus/baumanni) was the predominant OTU in the aerator of the fattening tank and also in the nearby sink on the floor. The genera Cetobacterium and Bacteroides showed highest relative abundances in the samples from the larval rearing tank and the pre-fattening tank. Genera including fish pathogens (Fusobacterium, Aeromonas) were only detected at low relative abundances. Potential human pathogens other than Acinetobacter were either not detected or had very low relative abundances (< 0.01%). The results of the study suggest that the main risk factors to be monitored in tilapia farm are putative human

  10. Analysis of bacterial contamination on surface of general radiography equipment and CT equipment in emergency room of radiology

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Dong Hee; KIm, Hyeong Gyun [Dept. of Radiological Science, Far East University, Eumseong (Korea, Republic of)

    2016-09-15

    We aim to offer basic materials about infection management through conducting bacterial contamination test about general radiography equipment and CT equipment installed in ER of three general hospitals with 100 sickbeds or more located in Gyeongsangbuk-do Province, and suggest management plan. It had been conducted from 1st December 2015 to 31st December, and objects were general radiography equipment and CT equipment of emergency room located in Gyeongsangbuk-do Province. For general radiography equipment, sources were collected from 4 places such as upper side of control box which employees use most, upper side of exposure button, whole upper side of table which is touching part of patient's skin, upper side of stand bucky's grid, and where patients put their jaws on. For CT equipment, sources were collected from 3 places such as upper side of control box which radiography room employees use most, X-ray exposure button, whole upper side of table which is touching part of patient's skin, and gantry inner. Surface contamination strain found at general radiography equipment in emergency room of radiology are Providencia stuartii(25%), Stenotrophomonas maltophilia(18%), Enterobacter cloacae(8%), Pseudomonas species(8%), Staphylococcus epidermidis(8%), Gram negative bacilli(8%), and ungrown bacteria at incubator after 48 hours of incubation (67%) which is the biggest. Most bacteria were found at upper side of stand bucky-grid and stand bucky of radiology's general radiography equipment, and most sources of CT equipment were focused at patient table, which means it is contaminated by patients who have various diseases, and patients who have strains with decreased immunity may get severe diseases. Thus infection prevention should be made through 70% alcohol disinfection at both before test and after test.

  11. Characterization of the gacA-dependent surface and coral mucus colonization by an opportunistic coral pathogen Serratia marcescens PDL100.

    Science.gov (United States)

    Krediet, Cory J; Carpinone, Emily M; Ritchie, Kim B; Teplitski, Max

    2013-05-01

    Opportunistic pathogens rely on global regulatory systems to assess the environment and to control virulence and metabolism to overcome host defenses and outcompete host-associated microbiota. In Gammaproteobacteria, GacS/GacA is one such regulatory system. GacA orthologs direct the expression of the csr (rsm) small regulatory RNAs, which through their interaction with the RNA-binding protein CsrA (RsmA), control genes with functions in carbon metabolism, motility, biofilm formation, and virulence. The csrB gene was controlled by gacA in Serratia marcescens PDL100. A disruption of the S. marcescens gacA gene resulted in an increased fitness of the mutant on mucus of the host coral Acropora palmata and its high molecular weight fraction, whereas the mutant was as competitive as the wild type on the low molecular weight fraction of the mucus. Swarming motility and biofilm formation were reduced in the gacA mutant. This indicates a critical role for gacA in the efficient utilization of specific components of coral mucus and establishment within the surface mucopolysaccharide layer. While significantly affecting early colonization behaviors (coral mucus utilization, swarming motility, and biofilm formation), gacA was not required for virulence of S. marcescens PDL100 in either a model polyp Aiptasia pallida or in brine shrimp Artemia nauplii. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  12. Evaluating bacterial community structures in oil collected from the sea surface and sediment in the northern Gulf of Mexico after the Deepwater Horizon oil spill

    OpenAIRE

    Liu, Zhanfei; Liu, Jiqing

    2013-01-01

    Bacterial community structures were evaluated in oil samples using culture-independent pyrosequencing, including oil mousses collected on sea surface and salt marshes during the Deepwater Horizon oil spill, and oil deposited in sediments adjacent to the wellhead 1 year after the spill. Phylogenetic analysis suggested that Erythrobacter, Rhodovulum, Stappia, and Thalassospira of Alphaproteobacteria were the prevailing groups in the oil mousses, which may relate to high temperatures and strong ...

  13. In-vitro experimental evaluation of skin-to-surface recovery of four bacterial species by antibacterial and non-antibacterial medical examination gloves.

    Science.gov (United States)

    Leitgeb, Johannes; Schuster, Rupert; Eng, Aik-Hwee; Yee, Bit-New; Teh, Yee-Peng; Dosch, Verena; Assadian, Ojan

    2013-10-11

    The number of bacteria recovered from a stainless steel coupon after touching a pigskin substrate with an examination glove coated on its outside with polyhexanide (PHMB), as compared to the number of bacteria recovered in the same manner with non-coated control gloves was evaluated. Suspensions containing 1 × 109 colony-forming units of 4 clinically relevant bacterial species (Enterococcus faecium ATCC #51559; Escherichia coli ATCC #25922; Klebsiella pneumoniae ATCC #4352; and Staphylococcus aureus ATCC #33591) were used to contaminate Gamma-irradiated pigskin substrates. Bacterial recoveries from the pigskin substrate, stainless steel coupons, and each glove swatch were performed. A difference in the bacterial recovery from the stainless steel coupons after touching with coated and uncoated control gloves was measured. For E. faecium, the coated glove showed a reduction of 4.63 log10 cfu recovery, when compared to control gloves. For E. coli, the coated glove showed 5.48 log10 cfu, for K. pneumoniae 5.03 log10 cfu, and for S. aureus 5.72 log10 cfu recovery, when compared to the non-coated control glove. An in-vitro experiment designed to mimic cross-contamination of clinically relevant bacteria in a simulated healthcare setting following glove contact with a contaminated biological surface and cross-transfer to a stainless steel surface has demonstrated that an examination glove coated on its outside surface with PHMB was able to reduce bacterial recovery from a contaminated surface by > 4 log10 cfu, compared to a control non-coated examination glove. These elaborated results may encourage further clinical investigation on the clinical impact of an antibacterial examination glove.

  14. Phenotypic Heterogeneity and the Evolution of Bacterial Life Cycles.

    Science.gov (United States)

    van Gestel, Jordi; Nowak, Martin A

    2016-02-01

    Most bacteria live in colonies, where they often express different cell types. The ecological significance of these cell types and their evolutionary origin are often unknown. Here, we study the evolution of cell differentiation in the context of surface colonization. We particularly focus on the evolution of a 'sticky' cell type that is required for surface attachment, but is costly to express. The sticky cells not only facilitate their own attachment, but also that of non-sticky cells. Using individual-based simulations, we show that surface colonization rapidly evolves and in most cases leads to phenotypic heterogeneity, in which sticky and non-sticky cells occur side by side on the surface. In the presence of regulation, cell differentiation leads to a remarkable set of bacterial life cycles, in which cells alternate between living in the liquid and living on the surface. The dominant life stage is formed by the surface-attached colony that shows many complex features: colonies reproduce via fission and by producing migratory propagules; cells inside the colony divide labour; and colonies can produce filaments to facilitate expansion. Overall, our model illustrates how the evolution of an adhesive cell type goes hand in hand with the evolution of complex bacterial life cycles.

  15. Candida krusei isolated from fruit juices ultrafiltration membranes promotes colonization of Escherichia coli O157:H7 and Salmonella enterica on stainless steel surfaces.

    Science.gov (United States)

    Tarifa, María Clara; Lozano, Jorge Enrique; Brugnoni, Lorena Inés

    2017-02-01

    To clarify the interactions between a common food spoilage yeast and two pathogenic bacteria involved in outbreaks associated with fruit juices, the present paper studies the effect of the interplay of Candida krusei, collected from UF membranes, with Escherichia coli O157:H7 and Salmonella enterica in the overall process of adhesion and colonization of abiotic surfaces. Two different cases were tested: a) co-adhesion by pathogenic bacteria and yeasts, and b) incorporation of bacteria to pre-adhered C. krusei cells. Cultures were made on stainless steel at 25°C using apple juice as culture medium. After 24 h of co-adhesion with C. krusei, both E. coli O157:H7 and S. enterica increased their counts 1.05 and 1.11 log CFU cm 2 , respectively. Similar increases were obtained when incorporating bacteria to pre-adhered cells of Candida. Nevertheless C. krusei counts decreased in both experimental conditions, in a) 0.40 log CFU cm 2 and 0.55 log CFU cm 2 when exposed to E. coli O157:H7 and S. enterica and in b) 0.18 and 0.68 log CFU cm 2 , respectively. This suggests that C. krusei, E. coli O157:H7, and S. enterica have a complex relationship involving physical and chemical interactions on food contact surfaces. This study supports the possibility that pathogen interactions with members of spoilage microbiota, such as C. krusei, might play an important role for the survival and dissemination of E. coli O157:H7 and Salmonella enterica in food-processing environments. Based on the data obtained from the present study, much more attention should be given to prevent the contamination of these pathogens in acidic drinks.

  16. A short-time scale colloidal system reveals early bacterial adhesion dynamics.

    Directory of Open Access Journals (Sweden)

    Christophe Beloin

    2008-07-01

    Full Text Available The development of bacteria on abiotic surfaces has important public health and sanitary consequences. However, despite several decades of study of bacterial adhesion to inert surfaces, the biophysical mechanisms governing this process remain poorly understood, due, in particular, to the lack of methodologies covering the appropriate time scale. Using micrometric colloidal surface particles and flow cytometry analysis, we developed a rapid multiparametric approach to studying early events in adhesion of the bacterium Escherichia coli. This approach simultaneously describes the kinetics and amplitude of early steps in adhesion, changes in physicochemical surface properties within the first few seconds of adhesion, and the self-association state of attached and free-floating cells. Examination of the role of three well-characterized E. coli surface adhesion factors upon attachment to colloidal surfaces--curli fimbriae, F-conjugative pilus, and Ag43 adhesin--showed clear-cut differences in the very initial phases of surface colonization for cell-bearing surface structures, all known to promote biofilm development. Our multiparametric analysis revealed a correlation in the adhesion phase with cell-to-cell aggregation properties and demonstrated that this phenomenon amplified surface colonization once initial cell-surface attachment was achieved. Monitoring of real-time physico-chemical particle surface properties showed that surface-active molecules of bacterial origin quickly modified surface properties, providing new insight into the intricate relations connecting abiotic surface physicochemical properties and bacterial adhesion. Hence, the biophysical analytical method described here provides a new and relevant approach to quantitatively and kinetically investigating bacterial adhesion and biofilm development.

  17. Bacterial flora of the sigmoid neovagina

    NARCIS (Netherlands)

    T.A. Toolenaar; I. Freundt (Ingrid); J.H. Wagenvoort; F.J. Huikeshoven (Frans); M. Vogel; J. Jeekel (Hans); A.C. Drogendijk

    1993-01-01

    textabstractThe bacterial microbiota of 15 sigmoid neovaginas, created in patients with congenital vaginal aplasia or male transsexualism, was studied. No specimen was sterile, and only normal inhabitants of the colon were cultured. The total counts of bacteria were

  18. Metagenomic analysis of bacterial community composition and antibiotic resistance genes in a wastewater treatment plant and its receiving surface water.

    Science.gov (United States)

    Tang, Junying; Bu, Yuanqing; Zhang, Xu-Xiang; Huang, Kailong; He, Xiwei; Ye, Lin; Shan, Zhengjun; Ren, Hongqiang

    2016-10-01

    The presence of pathogenic bacteria and the dissemination of antibiotic resistance genes (ARGs) may pose big risks to the rivers that receive the effluent from municipal wastewater treatment plants (WWTPs). In this study, we investigated the changes of bacterial community and ARGs along treatment processes of one WWTP, and examined the effects of the effluent discharge on the bacterial community and ARGs in the receiving river. Pyrosequencing was applied to reveal bacterial community composition including potential bacterial pathogen, and Illumina high-throughput sequencing was used for profiling ARGs. The results showed that the WWTP had good removal efficiency on potential pathogenic bacteria (especially Arcobacter butzleri) and ARGs. Moreover, the bacterial communities of downstream and upstream of the river showed no significant difference. However, the increase in the abundance of potential pathogens and ARGs at effluent outfall was observed, indicating that WWTP effluent might contribute to the dissemination of potential pathogenic bacteria and ARGs in the receiving river. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Microbial colonization of irradiated pathogenic yeast to catheter surfaces: Relationship between adherence, cell surface hydrophobicity, biofilm formation and antifungal susceptibility. A scanning electron microscope analysis.

    Science.gov (United States)

    Farrag, Hala Abdallah; A-Karam El-Din, Alzahraa; Mohamed El-Sayed, Zeinab Galal; Abdel-Latifissa, Soheir; Kamal, Mona Mohamed

    2015-06-01

    Technological advances such as long-term indwelling catheters have created milieu in which infections are a major complication. Thus it is essential to be able to recognize, diagnose, and treat infections occurring in immunocompromised patients. Adherence assay and quantitation of biofilms was performed by a spectrophotometric method, hydrophobicity was evaluated by adhesion to p-xylene. The minimum inhibitory concentration (MIC) of Nystatin was carried out by a well dilution method. Out of 100 bladder cancer patients, 23 pathogenic yeast isolates were identified. The samples were taken from urinary catheters and urine collected from their attached drainage bags. Pathogenic yeast identified were species of Candida, Cryptococcus, Saccharomyces, Blastoschizomyces, Trichosporn, Hansenula, Prototheca and Rhodotorula. With the exception of Rhodotorula minuta, the yeast were sensitive to the antimycotic agent (Nystatin) used before and after in vitro gamma irradiation at 24.41 Gy as measured by a disc diffusion method. All tested yeast strains were slime producers and showed positive adherence reactions. There were considerable differences in adherence measurements after irradiation. An increase in adherence measurement values (using a spectrophotometric method) after irradiation were detected in four strains whereas eight other strains showed a reduction in their adherence reaction. The cell surface hydrophobicity (CSH) was evaluated by adhesion to p-xylene. Candida tropicalis showed a hydrophobic reaction with an increase in the cell surface hydrophobicity after irradiation. Scanning electron microscopy of irradiated C. tropicalis showed marked abnormalities in cell shape and size with significant reduction in adherence ability at the MIC level of Nystatin (4 μg/ml). More basic research at the level of pathogenesis and catheter substance is needed to design novel strategies to prevent fungal adherence and to inhibit biofilm formation.

  20. Degree of bacterial contamination and antibiotic susceptibility pattern of isolates from housekeeping surfaces in operating rooms and surgical wards at Jimma University Specialized Hospital, south west Ethiopia.

    Science.gov (United States)

    Genet, Chalachew; Kibru, Gebre; Hemalatha, Kannan

    2012-01-01

    The role of the hospital environment as a reservoir of potential pathogens has received increasing attention. There are several reports demonstrating contamination of a wide variety of environmental sites in operating rooms (ORs) and surgical wards (SWs) which lead to nosocomial spread. To determine the degree of bacterial contamination and antibiotic susceptibility pattern of isolates from floor and tabletop surfaces in ORs and SWs at Jimma University Specialized Hospital (JUSH). A cross sectional study was conducted on 144 floor and tabletop surfaces from October to January 2009/2010. Samples were investigated for identification of bacterial species following standard procedures and antimicrobial susceptibility tests were performed using disc diffusion technique. The data was analyzed using SPSS version 16 and compared with the proposed standard value. The mean aerobic colony counts (ACCs) for tabletop surfaces (34 CFU/cm2) and floors (19CFU/cm2) in SWs were significantly higher than the set ACC standard for hand contact surfaces (< 5 CFU/cm2) P < 0.00. The ACCs obtained from tabletop surfaces (6.2 CFU/cm2) and floors (10.1CFU/cm2) in ORs were also exceeding the standard. Over 55% of gram negative bacteria were identified from Critical Zone of ORs. Staphylococcus aureus was the must frequently isolated bacterium accounting 33.3% followed by Escherichia coli and Klebsiella spp each with 11.1%. Moreover, S. aureus showed 100% resistance to methicillin and multidrug resistant Enterobacteriaceae were also seen in more than 90 % of isolates. An increased bacterial contamination was measured in both ORs and SWs of the JUSH and the isolated bacteria were also resistant for most of the antibiotics used as a treatment options in the study area. Therefore, appropriate infection control measures needs to be taken to keep the contamination level within the proposed standard.

  1. Bactericidal effect of photocatalytically-active nanostructured TiO2surfaces on biofilms of the early oral colonizer, Streptococcus oralis.

    Science.gov (United States)

    Westas, Emma; Hayashi, Mariko; Cecchinato, Francesca; Wennerberg, Ann; Andersson, Martin; Jimbo, Ryo; Davies, Julia R

    2017-08-01

    This study evaluated the photocatalytic bactericidal effect of nanostructured anatase-rich titanium dioxide (TiO 2 ) on microbial biofilms. Commercially pure titanium discs were spin-coated with photocatalytic TiO 2 nanoparticles (P25). Uncoated discs were used as control (CTRL). Half of the CTRL and half of the P25-coated surfaces were coated with purified saliva (SAL) to give four different groups (CTRL, CTRL + SAL, P25 and P25 + SAL). Streptococcus oralis were allowed to form biofilms on the discs for 18 h and non-adherent cells were rinsed off. Bacterial viability was assessed at time 0 with Live/Dead BacLight staining and epifluorescence microscopy. The remaining discs were divided into a non-UV group and UVA-irradiated (+UV) group (irradiation time, 6 or 24 h). Thereafter, viability was assessed as above. Viability at time 0 was high and no dead cells were seen on any of the surfaces, even after 24 h, in the absence of UVA. However, after 24 h of exposure, the proportion of viable cells was reduced by 40% on the P25 discs compared to 0 and 6 h, and this effect was enhanced with a salivary pellicle. Members of mixed species biofilms differ in their susceptibility to the bactericidal effect of the surfaces tested and further investigations are needed to optimize the conditions. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2321-2328, 2017. © 2017 Wiley Periodicals, Inc.

  2. Evaluating bacterial community structures in oil collected from the sea surface and sediment in the northern Gulf of Mexico after the Deepwater Horizon oil spill.

    Science.gov (United States)

    Liu, Zhanfei; Liu, Jiqing

    2013-06-01

    Bacterial community structures were evaluated in oil samples using culture-independent pyrosequencing, including oil mousses collected on sea surface and salt marshes during the Deepwater Horizon oil spill, and oil deposited in sediments adjacent to the wellhead 1 year after the spill. Phylogenetic analysis suggested that Erythrobacter, Rhodovulum, Stappia, and Thalassospira of Alphaproteobacteria were the prevailing groups in the oil mousses, which may relate to high temperatures and strong irradiance in surface Gulf waters. In the mousse collected from the leaves of Spartina alterniflora, Vibrio of Gammaproteobacteria represented 57% of the total operational taxonomic units, suggesting that this indigenous genus is particularly responsive to the oil contamination in salt marshes. The bacterial communities in oil-contaminated sediments were highly diversified. The relatively high abundance of the Methylococcus, Methylobacter, Actinobacteria, Firmicutes, and Chlorofexi bacteria resembles those found in certain cold-seep sediments with gas hydrates. Bacterial communities in the overlying water of the oil-contaminated sediment were dominated by Ralstonia of Betaproteobacteria, which can degrade small aromatics, and Saccharophagus degradans of Gammaproteobacteria, a cellulose degrader, suggesting that overlying water was affected by the oil-contaminated sediments, possibly due to the dissolution of small aromatics and biosurfactants produced during biodegradation. Overall, these results provided key information needed to evaluate oil degradation in the region and develop future bioremediation strategies. © 2013 The Authors. Microbiology Open published by John Wiley & Sons Ltd.

  3. Colonization study of gfp-tagged Achromobacter marplatensis strain in sugar beet.

    Science.gov (United States)

    Shi, YingWu; Li, Chun; Yang, HongMei; Zhang, Tao; Gao, Yan; Chu, Min; Zeng, Jun; Lin, Qing; OuTiKuEr; Li, YuGuo; Huo, Xiangdong; Lou, Kai

    2017-04-01

    This study details the introduction of a gfp marker into an endophytic bacterial strain (Achromobacter marplatensis strain 17, isolated from sugar beet) to monitor its colonization of sugar beet (Beta. vulgaris L.). Stability of the plasmid encoding the gfp was confirmed in vitro for at least 72 h of bacterial growth and after the colonization of tissues, under nonselective conditions. The colonization was observed using fluorescence microscopy and enumeration of culturable endophytes in inoculated sugar beet plants that grew for 10 or 20 days. gfp-Expressing strains were re-isolated from the inner tissues of surface-sterilized roots and stems of inoculated plants, and the survival of the Achromobacter marplatensis 17:gfp strain in plants 20 days after inoculation, even in the absence of selective pressure, suggests that it is good colonizer. These results also suggest that this strain could be a useful tool for the delivery of enzymes or other proteins into plants. In addition, the study highlights that sugar beet plants can be used effectively for detailed in vitro studies on the interactions between A. marplatensis strain 17 and its host, particularly if a gfp-tagged strain of the pathogen is used.

  4. Colonization of Madagascar periwinkle (Catharanthus roseus), by endophytes encoding gfp marker.

    Science.gov (United States)

    Torres, Adalgisa Ribeiro; Araújo, Welington Luiz; Cursino, Luciana; de Barros Rossetto, Priscilla; Mondin, Mateus; Hungria, Mariangela; Azevedo, João Lúcio

    2013-07-01

    This study reports the introduction of gfp marker in two endophytic bacterial strains (Pantoea agglomerans C33.1, isolated from cocoa, and Enterobacter cloacae PR2/7, isolated from citrus) to monitor the colonization in Madagascar perinwinkle (Catharanthus roseus). Stability of the plasmid encoding gfp was confirmed in vitro for at least 72 h of bacterial growth and after the colonization of tissues, under non-selective conditions. The colonization was observed using fluorescence microscopy and enumeration of culturable endophytes in inoculated perinwinkle plants that grew for 10 and 20 days. Gfp-expressing strains were re-isolated from the inner tissues of surface-sterilized roots and stems of inoculated plants, and the survival of the P. agglomerans C33:1gfp in plants 20 days after inoculation, even in the absence of selective pressure, suggests that is good colonizer. These results indicated that both gfp-tagged strains, especially P. agglomerans C33.1, may be useful tools to deliver enzymes or other proteins in plant.

  5. Microbes on a Bottle: Substrate, Season and Geography Influence Community Composition of Microbes Colonizing Marine Plastic Debris.

    Directory of Open Access Journals (Sweden)

    Sonja Oberbeckmann

    Full Text Available Plastic debris pervades in our oceans and freshwater systems and the potential ecosystem-level impacts of this anthropogenic litter require urgent evaluation. Microbes readily colonize aquatic plastic debris and members of these biofilm communities are speculated to include pathogenic, toxic, invasive or plastic degrading-species. The influence of plastic-colonizing microorganisms on the fate of plastic debris is largely unknown, as is the role of plastic in selecting for unique microbial communities. This work aimed to characterize microbial biofilm communities colonizing single-use poly(ethylene terephthalate (PET drinking bottles, determine their plastic-specificity in contrast with seawater and glass-colonizing communities, and identify seasonal and geographical influences on the communities. A substrate recruitment experiment was established in which PET bottles were deployed for 5-6 weeks at three stations in the North Sea in three different seasons. The structure and composition of the PET-colonizing bacterial/archaeal and eukaryotic communities varied with season and station. Abundant PET-colonizing taxa belonged to the phylum Bacteroidetes (e.g. Flavobacteriaceae, Cryomorphaceae, Saprospiraceae-all known to degrade complex carbon substrates and diatoms (e.g. Coscinodiscophytina, Bacillariophytina. The PET-colonizing microbial communities differed significantly from free-living communities, but from particle-associated (>3 μm communities or those inhabiting glass substrates. These data suggest that microbial community assembly on plastics is driven by conventional marine biofilm processes, with the plastic surface serving as raft for attachment, rather than selecting for recruitment of plastic-specific microbial colonizers. A small proportion of taxa, notably, members of the Cryomorphaceae and Alcanivoraceae, were significantly discriminant of PET but not glass surfaces, conjuring the possibility that these groups may directly interact

  6. Microbes on a Bottle: Substrate, Season and Geography Influence Community Composition of Microbes Colonizing Marine Plastic Debris.

    Science.gov (United States)

    Oberbeckmann, Sonja; Osborn, A Mark; Duhaime, Melissa B

    2016-01-01

    Plastic debris pervades in our oceans and freshwater systems and the potential ecosystem-level impacts of this anthropogenic litter require urgent evaluation. Microbes readily colonize aquatic plastic debris and members of these biofilm communities are speculated to include pathogenic, toxic, invasive or plastic degrading-species. The influence of plastic-colonizing microorganisms on the fate of plastic debris is largely unknown, as is the role of plastic in selecting for unique microbial communities. This work aimed to characterize microbial biofilm communities colonizing single-use poly(ethylene terephthalate) (PET) drinking bottles, determine their plastic-specificity in contrast with seawater and glass-colonizing communities, and identify seasonal and geographical influences on the communities. A substrate recruitment experiment was established in which PET bottles were deployed for 5-6 weeks at three stations in the North Sea in three different seasons. The structure and composition of the PET-colonizing bacterial/archaeal and eukaryotic communities varied with season and station. Abundant PET-colonizing taxa belonged to the phylum Bacteroidetes (e.g. Flavobacteriaceae, Cryomorphaceae, Saprospiraceae-all known to degrade complex carbon substrates) and diatoms (e.g. Coscinodiscophytina, Bacillariophytina). The PET-colonizing microbial communities differed significantly from free-living communities, but from particle-associated (>3 μm) communities or those inhabiting glass substrates. These data suggest that microbial community assembly on plastics is driven by conventional marine biofilm processes, with the plastic surface serving as raft for attachment, rather than selecting for recruitment of plastic-specific microbial colonizers. A small proportion of taxa, notably, members of the Cryomorphaceae and Alcanivoraceae, were significantly discriminant of PET but not glass surfaces, conjuring the possibility that these groups may directly interact with the PET

  7. Microbes on a Bottle: Substrate, Season and Geography Influence Community Composition of Microbes Colonizing Marine Plastic Debris

    Science.gov (United States)

    Osborn, A. Mark

    2016-01-01

    Plastic debris pervades in our oceans and freshwater systems and the potential ecosystem-level impacts of this anthropogenic litter require urgent evaluation. Microbes readily colonize aquatic plastic debris and members of these biofilm communities are speculated to include pathogenic, toxic, invasive or plastic degrading-species. The influence of plastic-colonizing microorganisms on the fate of plastic debris is largely unknown, as is the role of plastic in selecting for unique microbial communities. This work aimed to characterize microbial biofilm communities colonizing single-use poly(ethylene terephthalate) (PET) drinking bottles, determine their plastic-specificity in contrast with seawater and glass-colonizing communities, and identify seasonal and geographical influences on the communities. A substrate recruitment experiment was established in which PET bottles were deployed for 5–6 weeks at three stations in the North Sea in three different seasons. The structure and composition of the PET-colonizing bacterial/archaeal and eukaryotic communities varied with season and station. Abundant PET-colonizing taxa belonged to the phylum Bacteroidetes (e.g. Flavobacteriaceae, Cryomorphaceae, Saprospiraceae—all known to degrade complex carbon substrates) and diatoms (e.g. Coscinodiscophytina, Bacillariophytina). The PET-colonizing microbial communities differed significantly from free-living communities, but from particle-associated (>3 μm) communities or those inhabiting glass substrates. These data suggest that microbial community assembly on plastics is driven by conventional marine biofilm processes, with the plastic surface serving as raft for attachment, rather than selecting for recruitment of plastic-specific microbial colonizers. A small proportion of taxa, notably, members of the Cryomorphaceae and Alcanivoraceae, were significantly discriminant of PET but not glass surfaces, conjuring the possibility that these groups may directly interact with the

  8. Effect of early measles vaccine on pneumococcal colonization

    DEFF Research Database (Denmark)

    Hansen, Nadja Skadkær; Byberg, Stine; Hervig Jacobsen, Lars

    2017-01-01

    BACKGROUND: Measles vaccine (MV) may have non-specific beneficial effects for child health and particularly seems to prevent respiratory infections. Streptococcus pneumoniae is the leading cause of bacterial pneumonia among children worldwide, and nasopharyngeal colonization precedes infection...

  9. Reductions in bacterial microorganisms by filtration and ozonation of the surface water supply at the USFWS Northeast Fishery Center

    Science.gov (United States)

    A water filtration and ozonation system was recently installed to treat creek water used to culture species of concern at the U.S. Fish and Wildlife Service's Northeast Fishery Center, Lamar National Fish Hatchery (NFH). Past experience with fish culture indicates that the following bacterial pathog...

  10. Angiodysplasia of the colon

    Science.gov (United States)

    Vascular ectasia of the colon; Colonic arteriovenous malformation; Hemorrhage - angiodysplasia; Bleed - angiodysplasia ... Angiodysplasia of the colon is mostly related to the aging and breakdown of the blood vessels. It is more common in older adults. ...

  11. Bacterial Keratitis

    Science.gov (United States)

    ... Español Eye Health / Eye Health A-Z Bacterial Keratitis Sections What Is Bacterial Keratitis? Bacterial Keratitis Symptoms ... Lens Care Bacterial Keratitis Treatment What Is Bacterial Keratitis? Leer en Español: ¿Qué Es la Queratitis Bacteriana? ...

  12. A review of engineered zirconia surfaces in biomedical applications

    OpenAIRE

    Yin, Ling; Nakanishi, Yoshitaka; Alao, Abdur-Rasheed; Song, Xiao-Fei; Abduo, Jaafar; Zhang, Yu

    2017-01-01

    Zirconia is widely used for load-bearing functional structures in medicine and dentistry. The quality of engineered zirconia surfaces determines not only the fracture and fatigue behaviour but also the low temperature degradation (ageing sensitivity), bacterial colonization and bonding strength of zirconia devices. This paper reviews the current manufacturing techniques for fabrication of zirconia surfaces in biomedical applications, particularly, in tooth and joint replacements, and influenc...

  13. Bacterial binding to extracellular proteins - in vitro adhesion

    DEFF Research Database (Denmark)

    Schou, C.; Fiehn, N.-E.

    1999-01-01

    Viridans streptococci, bacterial adherence, extracellular matrix proteins, surface receptors, endocarditis......Viridans streptococci, bacterial adherence, extracellular matrix proteins, surface receptors, endocarditis...

  14. A Phloem-Feeding Insect Transfers Bacterial Endophytic Communities between Grapevine Plants

    Directory of Open Access Journals (Sweden)

    Sebastiàn Lòpez-Fernàndez

    2017-05-01

    Full Text Available Bacterial endophytes colonize the inner tissues of host plants through the roots or through discontinuities on the plant surface, including wounds and stomata. Little is known regarding a possible role of insects in acquiring and transmitting non-phytopathogenic microorganisms from plant to plant, especially those endophytes that are beneficial symbionts providing plant protection properties and homeostatic stability to the host. To understand the ecological role of insects in the transmission of endophytic bacteria, we used freshly hatched nymphs of the American sap-feeding leafhopper Scaphoideus titanus (vector to transfer microorganisms across grapevine plants. After contact with the vector, sink plants were colonized by a complex endophytic community dominated by Proteobacteria, highly similar to that present in source plants. A similar bacterial community, but with a higher ratio of Firmicutes, was found on S. titanus. Insects feeding only on sink plants transferred an entirely different bacterial community dominated by Actinobacteria, where Mycobacterium sp., played a major role. Despite the fact that insects dwelled mostly on plant stems, the bacterial communities in plant roots resembled more closely those inside and on insects, when compared to those of above-ground plant organs. We prove here the potential of insect vectors to transfer entire endophytic bacterial communities between plants. We also describe the role of plants and bacterial endophytes in establishing microbial communities in plant-feeding insects.

  15. A Phloem-Feeding Insect Transfers Bacterial Endophytic Communities between Grapevine Plants

    Science.gov (United States)

    Lòpez-Fernàndez, Sebastiàn; Mazzoni, Valerio; Pedrazzoli, Federico; Pertot, Ilaria; Campisano, Andrea

    2017-01-01

    Bacterial endophytes colonize the inner tissues of host plants through the roots or through discontinuities on the plant surface, including wounds and stomata. Little is known regarding a possible role of insects in acquiring and transmitting non-phytopathogenic microorganisms from plant to plant, especially those endophytes that are beneficial symbionts providing plant protection properties and homeostatic stability to the host. To understand the ecological role of insects in the transmission of endophytic bacteria, we used freshly hatched nymphs of the American sap-feeding leafhopper Scaphoideus titanus (vector) to transfer microorganisms across grapevine plants. After contact with the vector, sink plants were colonized by a complex endophytic community dominated by Proteobacteria, highly similar to that present in source plants. A similar bacterial community, but with a higher ratio of Firmicutes, was found on S. titanus. Insects feeding only on sink plants transferred an entirely different bacterial community dominated by Actinobacteria, where Mycobacterium sp., played a major role. Despite the fact that insects dwelled mostly on plant stems, the bacterial communities in plant roots resembled more closely those inside and on insects, when compared to those of above-ground plant organs. We prove here the potential of insect vectors to transfer entire endophytic bacterial communities between plants. We also describe the role of plants and bacterial endophytes in establishing microbial communities in plant-feeding insects. PMID:28555131

  16. Second messenger-mediated tactile response by a bacterial rotary motor.

    Science.gov (United States)

    Hug, Isabelle; Deshpande, Siddharth; Sprecher, Kathrin S; Pfohl, Thomas; Jenal, Urs

    2017-10-27

    When bacteria encounter surfaces, they respond with surface colonization and virulence induction. The mechanisms of bacterial mechanosensation and downstream signaling remain poorly understood. Here, we describe a tactile sensing cascade in Caulobacter crescentus in which the flagellar motor acts as sensor. Surface-induced motor interference stimulated the production of the second messenger cyclic diguanylate by the motor-associated diguanylate cyclase DgcB. This led to the allosteric activation of the glycosyltransferase HfsJ to promote rapid synthesis of a polysaccharide adhesin and surface anchoring. Although the membrane-embedded motor unit was essential for surface sensing, mutants that lack external flagellar structures were hypersensitive to mechanical stimuli. Thus, the bacterial flagellar motor acts as a tetherless sensor reminiscent of mechanosensitive channels. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  17. Bacterial-viral interactions in the sea surface microlayer of a black carbon-dominated tropical coastal ecosystem (Halong Bay, Vietnam

    Directory of Open Access Journals (Sweden)

    A. S. Pradeep Ram

    2018-02-01

    Full Text Available Increasing human activity has raised concerns about the impact of deposition of anthropogenic combustion aerosols (i.e., black carbon; BC on marine processes. The sea surface microlayer (SML is a key gate for the introduction of atmospheric BC into the ocean; however, relatively little is known of the effects of BC on bacteria-virus interactions, which can strongly influence microbially mediated processes. To study the impact of BC on bacteria-virus interactions, field investigations involving collection from the SML and underlying water were carried out in Halong Bay (Vietnam. Most inorganic nutrient concentrations, as well as dissolved organic carbon, were modestly but significantly higher ('p' = 0.02–0.05 in the SML than in underlying water. The concentrations of particulate organic carbon (though not chlorophyll 'a' and of total particulate carbon, which was composed largely of particulate BC (mean = 1.7 ± 6.4 mmol L–1, were highly enriched in the SML, and showed high variability among stations. On average, microbial abundances (both bacteria and viruses and bacterial production were 2- and 5fold higher, respectively, in the SML than in underlying water. Significantly lower bacterial production ('p' 3 μm compared to the bulk sample, but our data overall suggest that bacterial production in the SML was stimulated by particulate BC. Higher bacterial production in the SML than in underlying water supported high viral lytic infection rates (from 5.3 to 30.1% which predominated over percent lysogeny (from undetected to 1.4%. The sorption of dissolved organic carbon by black carbon, accompanied by the high lytic infection rate in the black carbon-enriched SML, may modify microbially mediated processes and shift the net ecosystem metabolism (ratio of production and respiration to net heterotrophy and CO2 production in this critical layer between ocean and atmosphere.

  18. Quantitative Evaluation of Bacteria Adherent and in Biofilm on Single-Wall Carbon Nanotube-Coated Surfaces

    Directory of Open Access Journals (Sweden)

    Fabrizio Pantanella

    2011-01-01

    Full Text Available Biofilm is a common bacterial lifestyle, and it plays a crucial role in human health, causing biofilm-mediated infections. Recently, to counteract biofilm development, new nano-structured biomaterials have been proposed. However, data about the antibacterial properties of nano-structured surfaces are fragmentary and controversial, and, in particular, the susceptibility of nano-structured materials to colonization and biofilm formation by bacterial pathogens has not been yet thoroughly considered. Here, the ability of the pathogenic Streptococcus mutans and Pseudomonas aeruginosa to adhere and form biofilm on surfaces coated with single-wall carbon nanotubes (SWCNTs was analyzed. Our results showed that the surfaces of SWCNTs-coated glass beads (SWCNTs-GBs were colonized at the same extent of uncoated GBs both by S. mutans and P. aeruginosa. In conclusion, our results demonstrate that single wall SWCNTs-coated surfaces are not suitable to counteract bacterial adhesion and biofilm development.

  19. Bacteria colonizing paper machines

    OpenAIRE

    Ekman, Jaakko

    2011-01-01

    Bacteria growing in paper machines can cause several problems. Biofilms detaching from paper machine surfaces may lead to holes and spots in the end product or even break the paper web leading to expensive delays in production. Heat stable endospores will remain viable through the drying section of paper machine, increasing the microbial contamination of paper and board. Of the bacterial species regularly found in the end products, Bacillus cereus is the only one classified as a pathogen. Cer...

  20. Image diagnostic of colonic diseases - controversial questions

    International Nuclear Information System (INIS)

    Pomakov, P.; Rizov, A.; Stancheva, I.

    2013-01-01

    In the system of colonic diseases' diagnostic algorithm, fibrocolonoscopy (FCS) is defined as 'Golden Standard'. By this reason some X-ray diagnostic methods - irrigography, etc. are currently not being used in a number of health institutions. The aim of this study is a comparative analysis of FCS and irrigography diagnostic efficacy in various colonic diseases. For 10-years period, in cooperation with a gastroenterologist-gastroscopist, 2151 patients with various colonic diseases were evaluated by FCS and irrigography with pharmaco-diagnostics/when necessary. Advantage of FCS was established in diagnosing diseases with patho-morfologic changes on the inner surface of the colon - benign and malignant neoplastic processes, chronic inflammatory diseases, etc. At the same time functional changes - irritated colon syndrome, changes in defecation act, etc., are not an object of diagnosis through FCS. Correction in colonic diseases diagnostic algorithm is necessary. FCS should be mandatory. If result is negative - irrigography with pharmaco-diagnostics should be done. (authors)

  1. Ca2+ response in neutrophils after exposure to bacterial N-formyl-methionyl-leucyl-phenylalanine: delayed response in ulcerative colitis

    DEFF Research Database (Denmark)

    Vainer, Ben; Lamberth, Kasper; Brimnes, Jens

    2003-01-01

    In acute stages of ulcerative colitis (UC), neutrophils migrate from the circulation into inflamed colonic tissue, initiated by yet unknown stimuli. The bacterial peptide N-formyl-methionyl-leucyl-phenylalanine (FMLP) is a component of the surface membrane of colonic bacteria such as Escherichia...... mediated neutrophil migration is impaired in UC patients. The aim of the present work was to study the influx of Ca2+ into peripheral blood neutrophils of UC patients after exposure to FMLP and after binding of either beta 2-integrins or intercellular adhesion molecule-1 (ICAM-1)....

  2. [Acute bacterial exacerbation of chronic obstructive pulmonary disease and biofilm].

    Science.gov (United States)

    Legnani, Delfino

    2009-07-01

    The lower respiratory tract of patients affected by COPD is constantly colonized by pathogenic microrganisms such as H. influenzae, M. catarrhalis and S. pneumoniae. Role of bacterial colonization of big and small airways in patients affected by COPD is still unclear but it is likely to play a role in directly or indirectly maintaining the vicious circle of infection/inflammation. Colonizer pathogens are capable to stimulate mucus production, to alter the ciliary function by inducing dyskinesia and stasis; in addition, they represent a strong stimulus for neutrophils to come in the airways, which release elastase that, in turn, inhibit the mucus-ciliary function. The same pathogens are responsible for epithelial damage and chronic inflammation, by releasing neutrophilic elastase, leading to the damage progression and obstruction. Recent studies have also shown that infection sustained by H. influenzae is not limited to bronchial mucosa, i.e. surface epithelial cells, but that the pathogen is capable to penetrate cells, so spreading the infection in sub-epithelial cellular layers. In addition, the ability to produce biofilm is another possible defence mechanism which allows them to grow and colonise. Such a mechanism could in part explain the lack of response to antimicrobials and contribute to stimulation of parenchymal inflammatory response, the cause of pathological-anatomic damage which occurs in COPD. The impossibility to eradicate chronic infection and bacterial exacerbations of COPD are likely the elements that promt and worsen obstruction, so determining the disease's progression.

  3. Aerobic and Anaerobic Bacterial Isolates on the Surface and Core of Tonsils from Patients with Chronic Tonsillitis

    Directory of Open Access Journals (Sweden)

    Meera Niranjan Khadilkar

    2017-08-01

    Full Text Available Introduction Controversy regarding treatment of tonsillitis based on throat culture report still persists. If surface culture is a determinant of bacteriology of the core, then rational therapy could be aimed at organisms cultured by surface swab. Materials and Methods A Cross-sectional study was conducted on 100 patients of chronic tonsillitis who underwent tonsillectomy. Tonsil surface and core swabs were studied for aerobic and anaerobic growth. Result Eighty seven percent patients had aerobic growth on tonsil surface and ninety percent in tonsil core. Staphylococcus aureus was the commonest aerobic bacteria isolated. Anaerobic growth was present in 47% patients on tonsil surface, and 48% in core. Porphyromonas sp. was the commonest anaerobic bacterium isolated. Discussion There was no statistically significant difference between aerobic and anaerobic bacteria found in tonsil surface and core.  Conclusion Throat swabs adequately represent core pathogen, and are dependable in detecting bacteriology of chronic tonsillitis.

  4. Role of surface energy and nano-roughness in the removal efficiency of bacterial contamination by nonwoven wipes from frequently touched surfaces.

    Science.gov (United States)

    Edwards, Nicholas W M; Best, Emma L; Connell, Simon D; Goswami, Parikshit; Carr, Chris M; Wilcox, Mark H; Russell, Stephen J

    2017-01-01

    Healthcare associated infections (HCAIs) are responsible for substantial patient morbidity, mortality and economic cost. Infection control strategies for reducing rates of transmission include the use of nonwoven wipes to remove pathogenic bacteria from frequently touched surfaces. Wiping is a dynamic process that involves physicochemical mechanisms to detach and transfer bacteria to fibre surfaces within the wipe. The purpose of this study was to determine the extent to which systematic changes in fibre surface energy and nano-roughness influence removal of bacteria from an abiotic polymer surface in dry wiping conditions, without liquid detergents or disinfectants. Nonwoven wipe substrates composed of two commonly used fibre types, lyocell (cellulosic) and polypropylene, with different surface energies and nano-roughnesses, were manufactured using pilot-scale nonwoven facilities to produce samples of comparable structure and dimensional properties. The surface energy and nano-roughness of some lyocell substrates were further adjusted by either oxygen (O 2 ) or hexafluoroethane (C 2 F 6 ) gas plasma treatment. Static adpression wiping of an inoculated surface under dry conditions produced removal efficiencies of between 9.4% and 15.7%, with no significant difference ( p  nonwoven wipe substrates with a surface energy closest to that of the contaminated surface produced the highest E. coli removal efficiency, while the associated increase in fibre nano-roughness abrogated this trend with S. aureus and E. faecalis .

  5. Salt Reduction in a Model High-Salt Akawi Cheese: Effects on Bacterial Activity, pH, Moisture, Potential Bioactive Peptides, Amino Acids, and Growth of Human Colon Cells.

    Science.gov (United States)

    Gandhi, Akanksha; Shah, Nagendra P

    2016-04-01

    This study evaluated the effects of sodium chloride reduction and its substitution with potassium chloride on Akawi cheese during storage for 30 d at 4 °C. Survival of probiotic bacteria (Lactobacillus acidophilus, Lactobacillus casei, and Bifidobacterium longum) and starter bacteria (Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus), angiotensin-converting enzyme-inhibitory and antioxidant activities, and concentrations of standard amino acids as affected by storage in different brine solutions (10% NaCl, 7.5% NaCl, 7.5% NaCl+KCl [1:1], 5% NaCl, and 5% NaCl+KCl [1:1]) were investigated. Furthermore, viability of human colon cells and human colon cancer cells as affected by the extract showing improved peptide profiles, highest release of amino acids and antioxidant activity (that is, from cheese brined in 7.5% NaCl+KCl) was evaluated. Significant increase was observed in survival of probiotic bacteria in cheeses with low salt after 30 d. Calcium content decreased slightly during storage in all cheeses brined in various solutions. Further, no significant changes were observed in ACE-inhibitory activity and antioxidant activity of cheeses during storage. Interestingly, concentrations of 4 essential amino acids (phenylalanine, tryptophan, valine, and leucine) increased significantly during storage in brine solutions containing 7.5% total salt. Low concentration of cheese extract (100 μg/mL) significantly improved the growth of normal human colon cells, and reduced the growth of human colon cancer cells. Overall, the study revealed that cheese extracts from reduced-NaCl brine improved the growth of human colon cells, and the release of essential amino acids, but did not affect the activities of potential bioactive peptides. © 2016 Institute of Food Technologists®

  6. Membrane biofouling in a wastewater nitrification reactor: Microbial succession from autotrophic colonization to heterotrophic domination.

    Science.gov (United States)

    Lu, Huijie; Xue, Zheng; Saikaly, Pascal; Nunes, Suzana P; Bluver, Ted R; Liu, Wen-Tso

    2016-01-01

    Membrane biofouling is a complex process that involves bacterial adhesion, extracellular polymeric substances (EPS) excretion and utilization, and species interactions. To obtain a better understanding of the microbial ecology of biofouling process, this study conducted rigorous, time-course analyses on the structure, EPS and microbial composition of the fouling layer developed on ultrafiltration membranes in a nitrification bioreactor. During a 14-day fouling event, three phases were determined according to the flux decline and microbial succession patterns. In Phase I (0-2 days), small sludge flocs in the bulk liquid were selectively attached on membrane surfaces, leading to the formation of similar EPS and microbial community composition as the early biofilms. Dominant populations in small flocs, e.g., Nitrosomonas, Nitrobacter, and Acinetobacter spp., were also the major initial colonizers on membranes. In Phase II (2-4 d), fouling layer structure, EPS composition, and bacterial community went through significant changes. Initial colonizers were replaced by fast-growing and metabolically versatile heterotrophs (e.g., unclassified Sphingobacteria). The declining EPS polysaccharide to protein (PS:PN) ratios could be correlated well with the increase in microbial community diversity. In Phase III (5-14 d), heterotrophs comprised over 90% of the community, whereas biofilm structure and EPS composition remained relatively stable. In all phases, AOB and NOB were constantly found within the top 40% of the fouling layer, with the maximum concentrations around 15% from the top. The overall microbial succession pattern from autotrophic colonization to heterotrophic domination implied that MBR biofouling could be alleviated by forming larger bacterial flocs in bioreactor suspension (reducing autotrophic colonization), and by designing more specific cleaning procedures targeting dominant heterotrophs during typical filtration cycles. Copyright © 2015 Elsevier Ltd. All

  7. Membrane biofouling in a wastewater nitrification reactor: microbial succession from autotrophic colonization to heterotrophic domination

    KAUST Repository

    Lu, Huijie

    2015-10-22

    Membrane biofouling is a complex process that involves bacterial adhesion, extracellular polymeric substances (EPS) excretion and utilization, and species interactions. To obtain a better understanding of the microbial ecology of biofouling process, this study conducted rigorous, time-course analyses on the structure, EPS and microbial composition of the fouling layer developed on ultrafiltration membranes in a nitrification bioreactor. During a 14-day fouling event, three phases were determined according to the flux decline and microbial succession patterns. In Phase I (0-2 days), small sludge flocs in the bulk liquid were selectively attached on membrane surfaces, leading to the formation of similar EPS and microbial community composition as the early biofilms. Dominant populations in small flocs, e.g., Nitrosomonas, Nitrobacter, and Acinetobacter spp., were also the major initial colonizers on membranes. In Phase II (2-4 d), fouling layer structure, EPS composition, and bacterial community went through significant changes. Initial colonizers were replaced by fast-growing and metabolically versatile heterotrophs (e.g., unclassified Sphingobacteria). The declining EPS polysaccharide to protein (PS:PN) ratios could be correlated well with the increase in microbial community diversity. In Phase III (5-14 d), heterotrophs comprised over 90% of the community, whereas biofilm structure and EPS composition remained relatively stable. In all phases, AOB and NOB were constantly found within the top 40% of the fouling layer, with the maximum concentrations around 15% from the top. The overall microbial succession pattern from autotrophic colonization to heterotrophic domination implied that MBR biofouling could be alleviated by forming larger bacterial flocs in bioreactor suspension (reducing autotrophic colonization), and by designing more specific cleaning procedures targeting dominant heterotrophs during typical filtration cycles.

  8. Modeling the acid-base properties of bacterial surfaces: A combined spectroscopic and potentiometric study of the gram-positive bacterium Bacillus subtilis.

    Science.gov (United States)

    Leone, Laura; Ferri, Diego; Manfredi, Carla; Persson, Per; Shchukarev, Andrei; Sjöberg, Staffan; Loring, John

    2007-09-15

    In this study, macroscopic and spectroscopic data were combined to develop a surface complexation model that describes the acid-base properties of Bacillus subtilis. The bacteria were freeze-dried and then resuspended in 0.1 M NaCl ionic medium. Macroscopic measurements included potentiometric acid-base titrations and electrophoretic mobility measurements. In addition, ATR-FTIR spectra of wet pastes from suspensions of Bacillus subtilis at different pH values were collected. The least-squares program MAGPIE was used to generate a surface complexation model that takes into account the presence of three acid-base sites on the surface: tripple bond COOH, tripple bond NH+, and tripple bond PO-, which were identified previously by XPS measurements. Both potentiometric titration data and ATR-FTIR spectra were used quantitatively, and electrostatic effects at the charged bacterial surface were accounted for using the constant capacitance model. The model was calculated using two different approaches: in the first one XPS data were used to constrain the ratio of the total concentrations of all three surface sites. The capacitance of the double layer, the total buffer capacity, and the deprotonation constants of the tripple bond NH+, tripple bond POH, and tripple bond COOH species were determined in the fit. A second approach is presented in which the ratio determined by XPS of the total concentrations of tripple bond NH+ to tripple bond PO- sites is relaxed. The total concentration of tripple bond PO- sites was determined in the fit, while the deprotonation constant for tripple bond POH was manually varied until the minimization led to a model which predicted an isoelectric point that resulted in consistency with electrophoretic mobility data. The model explains well the buffering capacity of Bacillus subtilis suspensions in a wide pH range (between pH=3 and pH=9) which is of considerable environmental interest. In particular, a similar quantitative use of the IR data

  9. Metagenomic insights into zooplankton-associated bacterial communities

    DEFF Research Database (Denmark)

    De Corte, Daniele; Srivastava, Abhishek; Koski, Marja

    2018-01-01

    ocean. The zooplankton-associated bacterial community is able to colonize the zooplankton's internal and external surfaces by using a large set of adhesion mechanisms and to metabolize complex organic compounds released or exuded by the zooplankton such as chitin, taurine and other complex molecules....... Moreover, the high number of genes involved in iron and phosphorus metabolisms in the zooplankton-associated microbiome suggests that this zooplankton-associated bacterial community mediates specific biogeochemical processes (through the proliferation of specific taxa) that are generally underrepresented......, we assessed the phylogenetic composition and metabolic potential of microbial communities associated with crustacean zooplankton species collected in the North Atlantic. Using Illumina sequencing of the 16S rRNA gene we found significant differences between the microbial communities associated...

  10. Surface modification of zirconia with polydopamine to enhance fibroblast response and decrease bacterial activity in vitro: A potential technique for soft tissue engineering applications.

    Science.gov (United States)

    Liu, Mingyue; Zhou, Jianfeng; Yang, Yang; Zheng, Miao; Yang, Jianjun; Tan, Jianguo

    2015-12-01

    The quality of soft-tissue integration plays an important role in the short- and long-term success of dental implants. The aim of the present study was to provide a surface modification approach for zirconia implant abutment materials and to evaluate its influence on fibroblast behavior and oral bacteria adhesion, which are the two main factors influencing the quality of peri-implant soft-tissue seal. In this study, polydopamine (PDA)-coated zirconia was prepared and the surface characteristics were evaluated using scanning electron microscopy, atomic force microscopy, a contact-angle-measuring device, X-ray photoelectron spectroscopy, and Raman spectroscopy. The responses of human gingival fibroblasts (HGFs) to PDA-coated zirconia; i.e., adhesion, proliferation, morphology, protein synthesis, and gene expression, were analyzed. Additionally, the adhesion of Streptococcus gordonii and Streptococcus mutans to zirconia after PDA coating was assessed by scanning electron microscopy and live/dead staining. The material surface analyses suggested the successful coating of PDA onto the zirconia surface. The PDA coating significantly increased cell adhesion and proliferation compared with pristine zirconia. HGFs exhibited a high degree of spreading and secreted a high level of collagen type I on PDA-modified disks. Upregulation of integrin α5, β1, β3 and fibronectin was noted in HGFs cultured on PDA-coated zirconia. The number of adherent bacteria decreased significantly on zirconia after PDA coating. In summary, our result suggest that PDA is able to modify the surface of zirconia, influence HGFs' behavior and reduce bacterial adhesion. Therefore, this surface modification approach holds great potential for improving soft-tissue integration around zirconia abutments in clinical application. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Extracellular Polymeric Substance Production and Aggregated Bacteria Colonization Influence the Competition of Microbes in Biofilms

    Directory of Open Access Journals (Sweden)

    Pahala G. Jayathilake

    2017-09-01

    Full Text Available The production of extracellular polymeric substance (EPS is important for the survival of biofilms. However, EPS production is costly for bacteria and the bacterial strains that produce EPS (EPS+ grow in the same environment as non-producers (EPS− leading to competition between these strains for nutrients and space. The outcome of this competition is likely to be dependent on factors such as initial attachment, EPS production rate, ambient nutrient levels and quorum sensing. We use an Individual-based Model (IbM to study the competition between EPS+ and EPS− strains by varying the nature of initial colonizers which can either be in the form of single cells or multicellular aggregates. The microbes with EPS+ characteristics obtain a competitive advantage if they initially colonize the surface as smaller aggregates and are widely spread-out between the cells of EPS−, when both are deposited on the substratum. Furthermore, the results show that quorum sensing-regulated EPS production may significantly reduce the fitness of EPS producers when they initially deposit as aggregates. The results provide insights into how the distribution of bacterial aggregates during initial colonization could be a deciding factor in the competition among different strains in biofilms.

  12. Bacterial meningitis

    NARCIS (Netherlands)

    Roos, Karen L.; van de Beek, Diederik

    2010-01-01

    Bacterial meningitis is a neurological emergency. Empiric antimicrobial and adjunctive therapy should be initiated as soon as a single set of blood cultures has been obtained. Clinical signs suggestive of bacterial meningitis include fever, headache, meningismus, vomiting, photophobia, and an

  13. Surface chemistry and acid-base activity of Shewanella putrefaciens: Cell wall charging and metal binding to bacterial cell walls

    NARCIS (Netherlands)

    Claessens, Jacqueline Wilhelmien

    2006-01-01

    To gain insight into the surface chemistry of live microorganisms, pH stat experiments are combined with analyses of the time-dependent changes in solution chemistry using suspensions of live cells of Shewanella putrefaciens. The results of this study illustrate the complex response of the live

  14. Surface chemistry and acid-base activity of Shewanella putrefaciens : Cell wall charging and metal binding to bacterial cell walls

    NARCIS (Netherlands)

    Claessens, J.W.

    2006-01-01

    To gain insight into the surface chemistry of live microorganisms, pH stat experiments are combined with analyses of the time-dependent changes in solution chemistry using suspensions of live cells of Shewanella putrefaciens. The results of this study illustrate the complex response of the live

  15. Cadmium biosorption by ozonized activated sludge: The role of bacterial flocs surface properties and mixed liquor composition

    International Nuclear Information System (INIS)

    Laurent, Julien; Casellas, Magali; Pons, Marie-Noelle; Dagot, Christophe

    2010-01-01

    Cadmium uptake by activated sludge was studied following modifications of sludge composition and surface properties induced by ozone treatment. Ozone leads to the solubilization of sludge compounds as well as their mineralization, especially humic like substances. Small particles were formed following floc disintegration, leading to a decrease of average floc size. The study of surface properties underlined the mineralization as the number of surface binding sites decreased with the increase of ozone dose. Depending on ozone dose, cadmium uptake by activated sludge flocs was either increased or decreased. Different mechanisms were involved: below 10 mg O 3 /g TS, the increase of floc specific surface area following floc size decrease as well as the release of phosphate ions yielded an increase by 75% of cadmium uptake, due to the better availability of biosorption sites and the increase of precipitation. Inversely, at higher ozone doses, the number of biosorption sites decreased due to oxidation by ozone. Moreover, dissolved organic matter concentration increased and provided ligands for metal complexation. Cadmium uptake was therefore limited for ozone doses ranging from 10 to 16.8 mg O 3 /g TS.

  16. Detection of bacterial metabolites through dynamic acquisition from surface enhanced raman spectroscopy substrates integtrated in a centrifugal microfluidic platform

    DEFF Research Database (Denmark)

    Durucan, Onur; Morelli, Lidia; Schmidt, Michael Stenbæk

    2015-01-01

    In this work we present a novel technology that combines the advantages of centrifugal microfluidics with dynamic in-situ Surface Enhanced Raman Spectroscopy (SERS) sensing. Our technology is based on an automated readout system that allows on-line SERS acquisition on a rotating centrifugal...

  17. Comparative effectiveness of NiCl2, Ni- and NiO-NPs in controlling oral bacterial growth and biofilm formation on oral surfaces.

    Science.gov (United States)

    Khan, Shams Tabrez; Ahamed, Maqusood; Alhadlaq, Hisham A; Musarrat, Javed; Al-Khedhairy, Abdulaziz

    2013-12-01

    Oral ailments are often treated with antibiotics, which are rendered ineffective as bacteria continue to develop resistance against them. It has been suggested that the nanoparticles (NPs) approach may provide a safer and viable alternative to traditional antibacterial agents. Therefore, nickel (Ni)- and nickel oxide (NiO)-NPs were synthesized, characterized and assessed for their efficacy in reducing oral bacterial load in vitro. Also, the effects of bulk compound NiCl2 (Ni ions), along with the Ni- and NiO-NPs on bacterial exopolysaccharide (EPS) production and biofilm formation on the surface of artificial teeth, and acrylic dentures, were investigated. Total bacteria from a healthy male were collected and adjusted to 4×109cells/ml for all the tests. Effect of the NPs on growth, biofilm formation, EPS production and acid production from glucose was tested using standard protocols. Data revealed that the Ni-NPs (average size 41.23nm) exhibited an IC50 value of 73.37μg/ml against total oral bacteria. While, NiO-NPs (average size 35.67nm) were found less effective with much higher IC50 value of 197.18μg/ml. Indeed, the Ni ions exhibited greater biocidal activity with an IC50 value of 70μg/ml. Similar results were obtained with biofilm inhibition on the surfaces of dental prostheses. The results explicitly suggested the effectiveness of tested Ni compounds on the growth of oral bacteria and biofilm formation in the order as NiCl2>Ni-NPs>NiO-NPs. The results elucidated that Ni-NPs could serve as effective nanoantibiotics against oral bacteria. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Improving the Immunogenicity of the Mycobacterium bovis BCG Vaccine by Non-Genetic Bacterial Surface Decoration Using the Avidin-Biotin System.

    Directory of Open Access Journals (Sweden)

    Ting-Yu Angela Liao

    Full Text Available Current strategies to improve the current BCG vaccine attempt to over-express genes encoding specific M. tuberculosis (Mtb antigens and/or regulators of antigen presentation function, which indeed have the potential to reshape BCG in many ways. However, these approaches often face serious difficulties, in particular the efficiency and stability of gene expression via nucleic acid complementation and safety concerns associated with the introduction of exogenous DNA. As an alternative, we developed a novel non-genetic approach for rapid and efficient display of exogenous proteins on bacterial cell surface. The technology involves expression of proteins of interest in fusion with a mutant version of monomeric avidin that has the feature of reversible binding to biotin. Fusion proteins are then used to decorate the surface of biotinylated BCG. Surface coating of BCG with recombinant proteins was highly reproducible and stable. It also resisted to the freeze-drying shock routinely used in manufacturing conventional BCG. Modifications of BCG surface did not affect its growth in culture media neither its survival within the host cell. Macrophages phagocytized coated BCG bacteria, which efficiently delivered their surface cargo of avidin fusion proteins to MHC class I and class II antigen presentation compartments. Thereafter, chimeric proteins corresponding to a surrogate antigen derived from ovalbumin and the Mtb specific ESAT6 antigen were generated and tested for immunogenicity in vaccinated mice. We found that BCG displaying ovalbumin antigen induces an immune response with a magnitude similar to that induced by BCG genetically expressing the same surrogate antigen. We also found that BCG decorated with Mtb specific antigen ESAT6 successfully induces the expansion of specific T cell responses. This novel technology, therefore, represents a practical and effective alternative to DNA-based gene expression for upgrading the current BCG vaccine.

  19. Improving the Immunogenicity of the Mycobacterium bovis BCG Vaccine by Non-Genetic Bacterial Surface Decoration Using the Avidin-Biotin System

    Science.gov (United States)

    Liao, Ting-Yu Angela; Lau, Alice; Joseph, Sunil; Hytönen, Vesa; Hmama, Zakaria

    2015-01-01

    Current strategies to improve the current BCG vaccine attempt to over-express genes encoding specific M. tuberculosis (Mtb) antigens and/or regulators of antigen presentation function, which indeed have the potential to reshape BCG in many ways. However, these approaches often face serious difficulties, in particular the efficiency and stability of gene expression via nucleic acid complementation and safety concerns associated with the introduction of exogenous DNA. As an alternative, we developed a novel non-genetic approach for rapid and efficient display of exogenous proteins on bacterial cell surface. The technology involves expression of proteins of interest in fusion with a mutant version of monomeric avidin that has the feature of reversible binding to biotin. Fusion proteins are then used to decorate the surface of biotinylated BCG. Surface coating of BCG with recombinant proteins was highly reproducible and stable. It also resisted to the freeze-drying shock routinely used in manufacturing conventional BCG. Modifications of BCG surface did not affect its growth in culture media neither its survival within the host cell. Macrophages phagocytized coated BCG bacteria, which efficiently delivered their surface cargo of avidin fusion proteins to MHC class I and class II antigen presentation compartments. Thereafter, chimeric proteins corresponding to a surrogate antigen derived from ovalbumin and the Mtb specific ESAT6 antigen were generated and tested for immunogenicity in vaccinated mice. We found that BCG displaying ovalbumin antigen induces an immune response with a magnitude similar to that induced by BCG genetically expressing the same surrogate antigen. We also found that BCG decorated with Mtb specific antigen ESAT6 successfully induces the expansion of specific T cell responses. This novel technology, therefore, represents a practical and effective alternative to DNA-based gene expression for upgrading the current BCG vaccine. PMID:26716832

  20. Colon diverticula - slideshow

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/presentations/100158.htm Colon diverticula - series—Normal anatomy To use the sharing ... to slide 6 out of 6 Overview The colon, or large intestine, is a muscular tube that ...

  1. Preventing infection of osseointegrated transcutaneous implants: Incorporation of silver into preconditioned fibronectin-functionalized hydroxyapatite coatings suppresses Staphylococcus aureus colonization while promoting viable fibroblast growth in vitro.

    Science.gov (United States)

    Chimutengwende-Gordon, Mukai; Pendegrass, Catherine; Bayston, Roger; Blunn, Gordon

    2014-09-01

    The success of transcutaneous implants depends on the achievement of a soft tissue seal by enabling fibroblasts to win the race for the surface against bacteria. Fibronectin-functionalized hydroxyapatite coatings (HAFn) have been shown to improve dermal tissue ingrowth and attachment. However, during the early postoperative period before a soft tissue seal has formed, bacterial colonization may occur. This study explored the incorporation of silver, a broad spectrum antimicrobial agent, into HAFn coatings with the aim of reducing bacterial colonization. Silver is known to have dose-dependent cytotoxic effects. Therefore, the effects of silver incorporation into HAFn coatings on both in vitro human dermal fibroblast viability and Staphylococcus aureus colonization were assessed. An electrochemical deposition technique was used to codeposit hydroxyapatite and silver (HAAg) and fibronectin was adsorbed onto this to produce HAAgFn coatings. Surfaces were preconditioned with serum to mimic the in vivo environment. Nonpreconditioned HAAg and HAAgFn coatings suppressed bacterial colonization but were cytotoxic. After serum-preconditioning, more than 90% of fibroblasts that grew on all HAAg and HAAgFn coatings were viable. The highest silver content coatings tested (HAAg100 and HAAgFn100) resulted in a greater than 99% reduction in biofilm and planktonic bacterial numbers compared to HA and HAFn controls. Although HAAg100 had greater antibacterial activity than HAAgFn100, the findings of this study indicate that fibroblasts would win the race for the surface against S aureus on both HAAg100 and HAAgFn100 after serum-preconditioning.

  2. Bacterial surface-displayed GII.4 human norovirus capsid proteins bound to surface of Romaine lettuce through HBGA-like molecules

    Science.gov (United States)

    Human Noroviruses (HuNoVs) are the main cause of nonbacterial gastroenteritis. Contaminated produce is a main vehicle for dissemination of HuNoVs. In this study, we used an ice nucleation protein (INP) mediated surface display system to present the protruding domain of GII.4 HuNoV capsid protein (G...

  3. Bacterial attachment and biofilm formation on surfaces are reduced by small-diameter nanoscale pores: how small is small enough?

    OpenAIRE

    Feng, Guoping; Cheng, Yifan; Wang, Shu-Yi; Borca-Tasciuc, Diana A; Worobo, Randy W; Moraru, Carmen I

    2015-01-01

    Background/Objectives: Prevention of biofilm formation by bacteria is of critical importance to areas that directly affect human health and life including medicine, dentistry, food processing and water treatment. This work showcases an effective and affordable solution for reducing attachment and biofilm formation by several pathogenic bacteria commonly associated with foodborne illnesses and medical infections. Methods: Our approach exploits anodisation to create alumina surfaces with cylind...

  4. Phagocytosis escape by a Staphylococcus aureus protein that connects complement and coagulation proteins at the bacterial surface.

    Directory of Open Access Journals (Sweden)

    Ya-Ping Ko

    Full Text Available Upon contact with human plasma, bacteria are rapidly recognized by the complement system that labels their surface for uptake and clearance by phagocytic cells. Staphylococcus aureus secretes the 16 kD Extracellular fibrinogen binding protein (Efb that binds two different plasma proteins using separate domains: the Efb N-terminus binds to fibrinogen, while the C-terminus binds complement C3. In this study, we show that Efb blocks phagocytosis of S. aureus by human neutrophils. In vitro, we demonstrate that Efb blocks phagocytosis in plasma and in human whole blood. Using a mouse peritonitis model we show that Efb effectively blocks phagocytosis in vivo, either as a purified protein or when produced endogenously by S. aureus. Mutational analysis revealed that Efb requires both its fibrinogen and complement binding residues for phagocytic escape. Using confocal and transmission electron microscopy we show that Efb attracts fibrinogen to the surface of complement-labeled S. aureus generating a 'capsule'-like shield. This thick layer of fibrinogen shields both surface-bound C3b and antibodies from recognition by phagocytic receptors. This information is critical for future vaccination attempts, since opsonizing antibodies may not function in the presence of Efb. Altogether we discover that Efb from S. aureus uniquely escapes phagocytosis by forming a bridge between a complement and coagulation protein.

  5. Colonização bacteriana do canal cervical em gestantes com trabalho de parto prematuro ou ruptura prematura de membranas Cervical bacterial colonization in women with preterm labor or premature rupture of membranes

    Directory of Open Access Journals (Sweden)

    Giuliane Jesus Lajos

    2008-08-01

    Full Text Available OBJETIVO: estudar a colonização bacteriana do canal cervical em gestantes com trabalho de parto prematuro ou com ruptura prematura de membranas. MÉTODOS: foram avaliadas 212 gestantes com trabalho de parto prematuro ou ruptura prematura de membranas. Na admissão hospitalar foram coletadas duas amostras do conteúdo endocervical e realizadas bacterioscopia e cultura em meios ágar sangue e ágar chocolate. Foram analisadas associações da colonização endocervical com infecção do trato urinário materno, corioamnionite, utilização de antibióticos, sofrimento fetal, prematuridade e infecção e óbito neonatais. RESULTADOS: a prevalência de colonização endocervical foi 14,2% (IC95%=9,5-18,9%, com resultados similares entre os casos com trabalho de parto prematuro ou ruptura prematura de membranas. O microorganismo mais prevalente na população estudada foi o estreptococo do grupo B (9,4%, sendo também isolados Candida sp, Streptococcus sp, Streptococcus pneumoniae, Escherichia coli e Enterococcus sp. Das bacterioscopias analisadas, os achados mais freqüentes foram baixa prevalência de bacilos de Döderlein e elevado número de leucócitos. Em mulheres colonizadas, houve maior prevalência de infecção do trato urinário (23,8 versus 5,4%; pPURPOSE: to study cervical colonization in women with preterm labor or premature rupture of membranes. METHODS: two hundred and twelve pregnant women with preterm labor or premature rupture of membranes were studied. Two cervical samples from each woman were collected and bacterioscopy and culture were performed. Association of cervical microorganisms and urinary tract infection, chorioamnionitis, fetal stress, antibiotic use, prematurity, neonatal infection, and neonatal death were evaluated. RESULTS: the prevalence of endocervical colonization was 14.2% (CI95%=9.5-18.9%, with similar results in preterm labor or premature rupture of membranes. Group B streptococcus was the most prevalent

  6. Gut microbial colonization orchestrates TLR2 expression, signaling and epithelial proliferation in the small intestinal mucosa.

    Directory of Open Access Journals (Sweden)

    Nives Hörmann

    Full Text Available The gut microbiota is an environmental factor that determines renewal of the intestinal epithelium and remodeling of the intestinal mucosa. At present, it is not resolved if components of the gut microbiota can augment innate immune sensing in the intestinal epithelium via the up-regulation of Toll-like receptors (TLRs. Here, we report that colonization of germ-free (GF Swiss Webster mice with a complex gut microbiota augments expression of TLR2. The microbiota-dependent up-regulation of components of the TLR2 signaling complex could be reversed by a 7 day broad-spectrum antibiotic treatment. TLR2 downstream signaling via the mitogen-activated protein kinase (ERK1/2 and protein-kinase B (AKT induced by bacterial TLR2 agonists resulted in increased proliferation of the small intestinal epithelial cell line MODE-K. Mice that were colonized from birth with a normal gut microbiota (conventionally-raised; CONV-R showed signs of increased small intestinal renewal and apoptosis compared with GF controls as indicated by elevated mRNA levels of the proliferation markers Ki67 and Cyclin D1, elevated transcripts of the apoptosis marker Caspase-3 and increased numbers of TUNEL-positive cells per intestinal villus structure. In accordance, TLR2-deficient mice showed reduced proliferation and reduced apoptosis. Our findings suggest that a tuned proliferation response of epithelial cells following microbial colonization could aid to protect the host from its microbial colonizers and increase intestinal surface area.

  7. Intestinal translocation of clinical isolates of vancomycin-resistant Enterococcus faecalis and ESBL-producing Escherichia coli in a rat model of bacterial colonization and liver ischemia/reperfusion injury.

    Directory of Open Access Journals (Sweden)

    Karin M van der Heijden

    Full Text Available The objectives of this study were to develop a rat model of gastrointestinal colonization with vancomycin-resistant Enterococcus faecalis (VRE and extended-spectrum beta-lactamase (ESBL-producing E. coli and to evaluate intestinal translocation to blood and tissues after total and partial hepatic ischemia. Metho