Bacterial Surface Colonization Research Articles

Endotracheal Intubation: The Role of Sterility

There is a paucity of data regarding whether sterile handling of endotracheal tubes (ETTs) impacts the incidence and prevalence of pneumonia in the emergency, urgent, or elective clinical scenarios. Intensive care units employ infection control and reduction schemes to reduce pneumonia rates. A MEDLINE search of the English-language literature for the last 30 years was performed using the keywords "endotracheal intubation," "intubation," "pneumonia," "sinusitis," "tracheobronchitis," "nosocomial infection," and "infection." Data were limited to those papers addressing the role of sterile handling or passage of ETTs, infection with antibiotic-resistant micro-organisms, antibiotic prophylaxis, and the role of virulence determinants in supporting invasive infection. Also, a convenience sample of a single author's patients requiring tracheal intubation was undertaken. Data were acquired on tube handling, success of insertion, and subsequent occurrence of pneumonia. Virtually no data exist on the impact of sterile ETT handling, but unsterile manipulation of the ETT prior to insertion is common (112 of 154 intubation events). Within the limited patient sample, no conclusions may be drawn regarding the impact of unsterile handling on pneumonia rates, although sinusitis after nasotracheal intubation clearly increases the incidence of pneumonia. Biofilm generation as a facilitator of bacterial colonization of artificial airway surfaces is a ubiquitous virulence determinant that is not ameliorated by antibiotic administration. Unsterile ETT handling and insertion techniques are not clearly associated with pneumonia induction, but physiologically sound approaches that retard biofilm production may decrease pneumonia rates.

Inhibitory Effect of Synthetic Nano-Hydroxyapatite on Dental Caries

The objective of this study was to investigate the inhibitory effect of the synthetic nanohydroxyapatite (HA) on dental caries. The nano-HA was synthesized by using the depositing reaction of Ca (H2PO4)2. The artificial dental caries was made by using sour solution and inoculating Streptococcus mutans (S.mutans) to the Sprague-Dawley (SD) rat’s mouth respectively. After mineralization of solution of nano-HA for 10 days, the hardness of enamel was measured. The inhibitory effect of the synthetic nano-HA on dental caries was detected by gargling way to rinse the rat tooth with the solution of nano-HA in the animal test. Transmission electron microscopy (TEM) revealed that the dried HA particles were needle-like with ф5-20nm×60nm and the sintered HA particles were spherical with less than 100nm. The remineralized test indicated that the solution of nano-HA with different shapes enhanced the hardness of artificial caries and improved the remineralization of artificial caries. The animal test showed that the dried nano-HA had the inhibitory effect on dental caries. The good absorptive effect of the nano-HA on both the saliva protein and the glucans leads to the development of interventions that could reduce or modify bacterial colonization of tooth surfaces.

Wza the translocon for E. coli capsular polysaccharides defines a new class of membrane protein

Many types of bacteria produce extracellular polysaccharides (EPSs). Some are secreted polymers and show only limited association with the cell surface, whereas others are firmly attached to the cell surface and form a discrete structural layer, the capsule, which envelopes the cell and allows the bacteria to evade or counteract the host immune system. EPSs have critical roles in bacterial colonization of surfaces, such as epithelia and medical implants; in addition some EPSs have important industrial and biomedical applications in their own right. Here we describe the 2.26 A resolution structure of the 340 kDa octamer of Wza, an integral outer membrane lipoprotein, which is essential for group 1 capsule export in Escherichia coli. The transmembrane region is a novel alpha-helical barrel. The bulk of the Wza structure is located in the periplasm and comprises three novel domains forming a large central cavity. Wza is open to the extracellular environment but closed to the periplasm. We propose a route and mechanism for translocation of the capsular polysaccharide. This work may provide insight into the export of other large polar molecules such as DNA and proteins.

Quaternary uncoiling dynamics of type I fimbriae suggest regulatory mechanism for bacterial adhesion

<dm:abstracts xmlns:dm="http://www.elsevier.com/xml/dm/dtd"><ce:abstract xmlns:ce="http://www.elsevier.com/xml/common/dtd" view="all" class="author" id="aep-abstract-id17"><ce:section-title>Publisher Summary</ce:section-title><ce:abstract-sec view="all" id="aep-abstract-sec-id18"><ce:simple-para id="fsabs003" view="all">This chapter discusses about bacterial adhesions and their mucosal cell receptors. It also discusses selected postadhesion events and describes how they influence mucosal colonization. The specific binding interaction between the bacterial adhesions and host receptors allows the bacteria to firmly attach to particular sites on the mucosal surfaces and thereby resist dislocation by the hydrokinetic forces that typically act on these surfaces. Adhesion of bacteria to mucosal surfaces is an important determinant of the mucosal colonization—especially in determining its site and density. Several critical postadhesion events are necessary for the bacteria to successfully establish themselves on the mucosal surfaces and to initiate infection. These events include: alterations to the expression of virulence factors by bacteria and induction of physiologic changes on the mucosal surface. The advantages of inhibiting adhesion to prevent the bacterial colonization of mucosal surfaces rely on the assumption that the spread of strains with genotypic resistance to the methods applied are much slower than in the case of employing approaches aimed at killing the organisms.</ce:simple-para></ce:abstract-sec></ce:abstract></dm:abstracts>

Chemical inhibition of bacterial colonization by the red alga Bonnemaisonia hamifera

Attachment and growth are 2 major processes in bacterial colonization of surfaces in the sea. By inhibiting either or both of these processes, marine macroorganisms may defend themselves against bacterial infection and fouling. We tested crude extracts from 5 red seaweed species for their ability to inhibit bacterial growth and attachment. For this we used 11 strains of bacteria, represent- ing 5 different taxonomic groups. The effects on growth and attachment were tested by a standard disc-diffusion assay and by incorporating crude extracts into phytagel blocks that served as a surface for bacterial attachment. Extracts from one of the tested algae, Bonnemaisonia hamifera, were partic- ularly active and inhibited growth of 9 bacteria at concentrations volumetrically equivalent to whole algal tissue, or lower. The other 4 algal extracts had weak growth-inhibiting effects on only a few bacterial strains. None of the algal extracts exhibited broad-spectrum effects against bacterial attach- ment, but 4 of 5 algal extracts had some strain-specific effects. Surface extracts of B. hamifera tested on bacteria showed that metabolites are naturally present at sufficiently high concentrations in order to inhibit bacterial growth on the surface of the seaweed. In situ quantification of bacteria on B. ham- ifera also showed that this alga had significantly fewer bacteria on its surface compared to a co- existing alga. These findings suggest that B. hamifera naturally reduces its epibacterial abundance by production of broad-spectrum growth-inhibiting secondary metabolites. This is one of a few examples where ecologically relevant effects of algal metabolites on bacterial colonization have been shown.

Effects of Caribbean sponge secondary metabolites on bacterial surface colonization

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 40:191-203 (2005) - doi:10.3354/ame040191 Effects of Caribbean sponge secondary metabolites on bacterial surface colonization Sarah R. Kelly1, Eliane Garo2, Paul R. Jensen2, William Fenical2, Joseph R. Pawlik1,* 1Department of Biology and Marine Biology, Center for Marine Science, University of North Carolina at Wilmington, Wilmington, North Carolina 28403, USA2Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego,La Jolla, California 92093, USA *Corresponding author. Email: pawlikj@uncw.edu ABSTRACT: Crude organic tissue extracts from 8 species of Caribbean sponges were assayed for inhibitory effects on surface colonization using 24 environmental marine bacterial isolates, 4 known marine invertebrate pathogens, and 1 common fouling bacterium. Each extract was tested for its effects on bacterial attachment, growth and swarming. The 24 bacterial strains were isolated from sponge surfaces, nearby substrata, or adjacent seawater. Extracts were incorporated into agar for assays of bacterial attachment and swarming. Growth-inhibition assays were conducted with the standard agar disk-diffusion assay. Of the 24 bacterial isolates, 23 were significantly inhibited from attaching to an extract-treated agar surface; 1 isolate from the surface of Agelas conifera exhibited significantly enhanced attachment on agar treated with the extract of that sponge. Sponge extracts had the least effect on growth: of 184 assays, 11 displayed significant antibacterial activity, all of these from 4 sponge species (A. conifera, Ailochroia crassa, Amphimedon compressa, and Aplysina fulva). The same isolate from the surface of A. conifera that exhibited enhanced attachment in response to the extract of that sponge exhibited inhibited growth in response to the same extract. Six out of 24 bacterial isolates exhibited swarming, the majority (67%) of which were isolated from substratum sources. Extracts from 4 of the 8 sponge species (the same species as listed above) inhibited swarming in all 6 strains, while the remaining extracts enhanced, inhibited, or had no effect on swarming depending on the strain. Bioassay-guided fractionation of the extract of A. crassa yielded 2 compounds responsible for inhibiting attachment and swarming, respectively. Ianthellin was identified as the metabolite that inhibited attachment, whereas another brominated tryosine metabolite inhibited swarming. Chemical defenses of sponges may target microbial attachment, and to a lesser degree influence swarming and growth. Non-toxic metabolites may play the greatest role in affecting bacterial epibiosis on the surfaces of marine sponges. KEY WORDS: Bacterial attachment · Bacterial swarming · Bromotyrosine metabolites · Microbial chemical defense · Quorum sensing · Antibacterial Full text in pdf format PreviousExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 40, No. 2. Online publication date: September 06, 2005 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2005 Inter-Research.

Minerals, metals and molecules: ore and environmental mineralogy in the new millennium

AbstractAspects of the (bio)geochemical cycling of metals (including Fe, Cu, Pb, Zn, Hg, As, Sb, U, Tc, Np) at or near the Earth's surface are discussed with reference to the recent work of the authors. Key stages of the breakdown of metalliferous minerals, transport of metals as solution complexes or colloidal precipitates, and interaction of metals in solution with the surfaces of minerals are considered. Emphasis is on molecular-scale observations using techniques such as scanning probe microscopy, photoelectron and (synchrotron) X-ray spectroscopies. The importance of the biological/mineralogical interface is also emphasized with reference to the bacterial colonization of mineral surfaces and formation of biofilms, and their influence on mineral surface reactivity and flow of fluids through rocks and sediments. Also noted is the importance of relating molecular and micro-scale observations to macroscopic phenomena. Molecular-scale understanding is central to attempts to model many processes of relevance in mineral exploration and exploitation, and in the containment of hazardous wastes and remediation of polluted areas. Mineralogists have a central role to play in the relevant environmental sciences and technologies.

9] Biofilm-induced gene expression and gene transfer

Publisher Summary This chapter discusses the transition of bacterial cells from a planktonic state to a biofilm state, involving adhesion to a substrate, to other cells along with production of extracellular polysaccharides, represents a major physiological change for bacteria, and is the process that drives bacterial colonization of inert and biological surfaces. Evidence is accumulating that bacteria in biofilms are not simply planktonic cells adherent to a surface, but rather exhibit considerable biofilm-induced phenotypic variation dependent on highly orchestrated changes in gene expression. The phenotypic properties of biofilm-mode bacteria can depend on plasmid stability and transfer with the biofilm. The close proximity of cells within a biofilm, combined with the presence of matrix material that can concentrate compounds—such as, plasmid and chromosomal DNA, pheromones, and bacteriophage—is conducive to the exchange of mobile genetic elements by processes such as conjugation, transposition, and transduction. Molecular definition of biofilm dependent changes in gene expression and plasmid transfer is thus necessary to understand the unique properties of biofilms.

Inhibiting bacterial adhesion onto surfaces: the non-stick coating approach

The use of low-surface-energy poly(methylpropenoxyfluoroalkylsiloxane) or poly(perfluoroacrylate) coatings as a potential means of inhibiting the bacterial colonisation of surfaces, is described and discussed.

Bacterial adhesins: function and structure

Specific adhesion to host tissue cells is an essential virulence factor of most bacterial pathogens. The fundamental processes that determine bacterial attachment to host tissue surfaces are mediated by microbial adhesins. Host specificity and tissue tropism are characteristics exhibited by different bacteria and are determined (at least in part) by the interaction between adhesins and their complementary receptors on host cell surfaces. A detailed picture of how bacteria are able to target to various receptors is emerging. A large number of bacterial adhesins with individual receptor specificities have been identified. Furthermore, recent research has shown that individual adhesins are prone to rapid microevolution that results in changes in the receptor specificity of individual adhesins. Microbial adhesins are often assembled into complex polymeric organelle structures, however non-organelle adhesins linked to the cell surface as monomers or simple oligomers also exist. This review gives an overview of bacterial adhesins and focuses on some general aspects of their biogenesis and role in bacterial colonization of host cell surfaces and as virulence factors.

Preventing bacterial adhesion onto surfaces: the low-surface-energy approach

Good-quality coatings prepared from poly(methylpropenoxyfluoroalkylsiloxane)s or poly(perfluoroacrylate)s are capable of inhibiting the bacterial colonisation of surfaces.

Evidence that halogenated furanones from Delisea pulchra inhibit acylated homoserine lactone (AHL)-mediated gene expression by displacing the AHL signal from its receptor protein.

Acylated homoserine lactone (AHL)-mediated gene expression controls phenotypes involved in colonization, often specifically of higher organisms, in both marine and terrestrial environments. The marine red alga Delisea pulchra produces halogenated furanones which resemble AHLs structurally and show inhibitory activity at ecologically realistic concentrations in AHL bioassays. Evidence is presented that halogenated furanones displace tritiated OHHL [N-3-(oxohexanoyl)-L-homoserine lactone] from Escherichia coli cells overproducing LuxR with potencies corresponding to their respective inhibitory activities in an AHL-regulated bioluminescence assay, indicating that this is the mechanism by which furanones inhibit AHL-dependent phenotypes. Alternative mechanisms for this phenomenon are also addressed. General metabolic disruption was assessed with two-dimensional PAGE, revealing limited non-AHL-related effects. A direct chemical interaction between the algal compounds and AHLs, as monitored by 1H NMR spectroscopy, was shown not to occur in vitro. These results support the contention that furanones, at the concentrations produced by the alga, can control bacterial colonization of surfaces by specifically interfering with AHL-mediated gene expression at the level of the LuxR protein.

Effects of Substratum Topography on Bacterial Adhesion

The effect of substratum topography on bacterial surface colonization was studied using a chemically homogeneous silicon coupon. “Grooves” 10 μm deep and 10, 20, 30, and 40 μm wide were etched on the coupon perpendicular to the direction of flow. Flow (Re = 5.5) of a bacterial suspension (108cells/ml) was directed through a parallel plate flow chamber inverted on a confocal microscope. Images were collected in real time to obtain rate and endpoint colonization data for each of three strains of bacteria:Pseudomonas aeruginosaand motile and nonmotilePseudomonas fluorescens.A higher velocity experiment (Re = 16.6) and an abiotic control using hydrophilic, negatively charged microspheres were also performed. Using a colloidal deposition expression, the initial rates of attachment were compared.P. aeruginosaattached at a higher rate thanP. fluorescensmot+ which attached at a higher rate thanP. fluorescensmot−. For all bacteria the rate was independent of groove size and was greatest on the downstream edges of the grooves. Only the motile organisms were found in the bottoms of the grooves. A higher fluid velocity resulted in an increase in the initial rate of attachment. In contrast, there was no adhesion of the beads. Attachment of the bacteria appears to be predominated by transport from the bulk phase to the substratum.

Influence of surface properties on accumulation of conditioning films and marine bacteria on substrata exposed to oligotrophic waters

The influence of interfacial wettabilities on initial conditioning and bacterial colonization of polished surfaces was examined in the oligotrophic, subtropical waters off O'ahu's south shore and in the laboratory. After exposures to seawater for 3 d, accumulations of attached bacteria on 11 types of substrata during two deployments varied as a second order function of substratum wettability. As observed in previous biomedical and mesotrophic field studies, surfaces with intermediate critical surface tensions (γcrit = 20–30 mN m‐1) and extremes in the polar and dispersive components of the composite surface free energy were least colonized by bacteria. Conditioning film thicknesses, varied by a factor of 100 among materials and also appeared to be a second order function of γcrit. Sorbed films produced interfaces with a range of wettabilities, dependent upon substratum and sorbate properties. Bacteria isolated from surfaces exhibited four basic partitioning patterns into non‐aqueous solvents which demonstrates that cell surface wettabilities vary widely among isolates and are characterized as (i) broadly hydrophobic, (ii) broadly hydrophilic, (iii) only compatible in phases with surface tensions < 20 mN m‐1, or (iv) only compatible in phases with surface tension > 27 mN m‐1. Partitioning patterns of cultured isolates are consistent with field observations of denser colonization of low and high γcrit surfaces. The results support the hypothesis that substratum surface properties influence conditioning film attributes and continue to exert control over bacterial adsorption and attachment even after conditioning films are established.

Bioactivity of echinoderm ethanolic body-wall extracts: an assessment of marine bacterial attachment and macroinvertebrate larval settlement

The ethanolic body-wall extracts of 16 species of echinoderms from 16 genera were screened for their ability to affect the attachment of the marine bacteria Deleya marina (Baumann) and Alteromonas luteo-violacea (Gauthier). Body-wall extracts were tested at concentrations which mimic mean natural tissue concentration, 3.0 mg/ml seawater, and four half-log dilutions of this initial concentration. The extracts of three echinoderm species caused significant inhibition of bacterial attachment, while extracts of eight species caused significant enhancement of attachment. The body-wall extract of the asteroid Goniaster tesselatus (Lamarck) displayed the most potent antimicrobial activity, completely inhibiting attachment of both bacterial species at a concentration of 3.0 mg/ml seawater. The ethanolic extracts of 20 echinoderm species were also tested at a similar range of concentrations for their ability to affect the settlement of cyprid larvae of the barnacle Balanus amphitrite (Darwin), and coronate larvae of the bryozoan Bugula neritina (Linné). All echinoderm extracts inhibited settlement of both barnacle and bryozoan larvae at the highest concentration tested (3.0 mg/ml seawater). Eleven of the 20 echinoderms tested (13 asteroids, 3 holothuroids, 3 ophiuroids and a crinoid) had body-wall extracts that inhibited settlement of competent barnacle and bryozoan larvae at concentrations as low as 0.12 mg/ml seawater. These extracted echinoderm compounds may function as non-toxic or toxic antifoulants, and to promote bacterial surface colonization, which could be valuable to the organisms disease resistance.

Adherence of oral microorganisms to human parotid salivary proteins.

Bacterial colonisation of oral surfaces by microorganisms may be dependent on their interaction with specific host receptor molecules. Primary oral colonisers are known to remove specific proteins from parotid saliva. The aim of this study was to determine whether these interactions facilitate microbial attachment to a surface and hence identify specific salivary components as putative host receptor molecules. Parotid saliva was resolved by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and then electroblotted onto nitrocellulose membranes. Suspensions of fluorescently labelled microorganisms were incubated with the blots and salivary components with adherent bacteria identified as fluorescent bands under ultraviolet (UV) transillumination. Species of streptococci known to be early colonisers of the clean tooth surface were found to adhere specifically to certain salivary proteins, especially to basic proline-rich proteins (PRPs). Polymorphic variations in these patterns could form the basis of differences in oral microflora, susceptibility to oral infections and consequent disease.

Salivary factors in caries models.

Consideration of salivary factors in caries models rarely extends beyond viewing saliva as a sink or diluent for plaque metabolic products, or as a source of buffering, for neutralizing plaque acids. In reality, saliva has a complex chemistry and a wide range of biochemical activities that may significantly affect plaque chemistry and microbiology. Thus, saliva is a major source of microbial nutrients, without which bacterial acid production is diminished. Buffering by salivary bicarbonate, and base production from urea and basic amino acids and peptides, significantly affect Stephan curves. Saliva is supersaturated with respect to basic calcium phosphate salts and contains novel inhibitors of calcium phosphate precipitation, while specific salivary proteins bind calcium. It seems important to consider if this system is reflected in plaque. Saliva, with contributions from serum and bacterial constituents, provides most of the precursors for the acquired enamel pellicle, which acts to slow demineralization during caries attack. Pellicle constituents appear to influence initial bacterial colonization of tooth surfaces and, therefore, may affect the microbial composition of plaque, but their detailed effects on plaque are poorly understood. Microbial adaptations to the anti-bacterial systems also seem important but are poorly investigated. Thus, saliva possesses an array of activities that have substantial actual or potential impact on plaque and, therefore, merit consideration for inclusion in systems intended to model dental caries.

Bacterial colonization of tegumental surfaces of Culaeatrema inconstans Lasee et al., 1988 (Digenea) from the brook stickleback, Culaea inconstans

Bacterial colonization of tegumental surfaces of <i>Culaeatrema inconstans</i> Lasee <i>et al.</i>, 1988 (Digenea) from the brook stickleback, <i>Culaea inconstans</i>

Characterization of initial events in bacterial surface colonization by two Pseudomonas species using image analysis

The processes leading to bacterial colonization on solid-water interfaces are adsorption, desorption, growth, and erosion. These processes have been measured individually in situ in a flowing system in real time using image analysis. Four different substrata (copper, silicon, 316 stainless-steel and glass) and 2 different bacterial species (Pseudomonas aeruginosa and Pseudomonas fluorescens) were used in the experiments. The flow was laminar (Re = 1.4) and the shear stress was kept constant during all experiments at 0.75 N m(-2). The surface roughness varied among the substrata from 0.002 microm (for silicon) to 0.015 microm (for copper). Surface free energies varied from 25.1 dynes cm(-1) for silicon to 31.2 dynes cm(-1) for copper. Cell curface hydrophobicity, reported as hydrocarbon partitioning values, ranged from 0.67 for Ps. fluorescens to 0.97 for Ps. aeruginosa.The adsorption rate coefficient varied by as much as a factor of 10 among the combinations of bacterial strain and substratum material, and was positively correlated with surface free energy, the surface roughness of the substratum, and the hydrophobicity of the cells. The probability of desorption decreased with increasing surface free energy and surface roughness of the substratum. Cell growth was inhibited on copper, but replication of cells overlying an initial cell layer was observed with increased exposure time to the cell-containing bulk water. A mathematical model describing cell accumulation on a substratum is presented.

The effect of some environmental parameters on surface colonization by microorganisms

The occurrence of biofouling in water systems results from microbial growth on submerged surfaces. Biofouling-related problems are often overcome by chemical treatment. However, situations often develop which necessitate a complete shutdown in order to allow mechanical cleaning of a system as well as replacement of corroded piping material. Strategies additional to chemical treatment are therefore needed to control biofouling. Such strategies may include physical or chemical alterations to a water system to create conditions less favourable for microbial activity. Different fluid velocities were simulated in a single continuous flow reactor which enabled the comparison of bacterial colonization of surfaces at six different fluid velocities while all other parameters were kept constant. As expected, the highest colonization rates occurred at conditions of zero flow, with a decrease in fouling rates with an increase of fluid velocity. In a second set of experiments, the influence of dissolved organic carbon concentration on biofouling of different types of surfaces was studied. In these experiments, highest colonization rates occurred on stainless steel, followed by aluminium and glass. Direct epifluorescent microscopy techniques were employed to enumerate sessile bacteria. There was a progressive increase in corrosion rate with increases in sulphate concentration up to sulphate levels greater than 600 mg/l after which there was no further marked increase in corrosion rate.