Adhesion Of Pathogenic Bacteria Research Articles

Elaboration of highly hydrophobic polymeric surface — a potential strategy to reduce the adhesion of pathogenic bacteria?

Different polymeric surfaces have been modified in order to reach a high hydrophobic character, indeed the superhydrophobicity property. For this purpose, polypropylene and polystyrene have been treated by RF or μwaves CF4 plasma with different volumes, the results were compared according to the density of injected power. The effect of pretreatment such as mechanical abrasion or plasma activation was also studied. The modified surfaces were shown as hydrophobic, or even superhydrophobic depending of defects density. They were characterized by measurement of wettability and roughness at different scales, i.e. macroscopic, mesoscopic and atomic. It has been shown that a homogeneous surface at the macroscopic scale could be heterogeneous at lower mesoscopic scale. This was associated with the crystallinity of the material. The bioadhesion tests were performed with Gram positive and negative pathogenic strains: Listeria monocytogenes, Pseudomonas aeruginosa and Hafnia alvei. They have demonstrated an antibacterial efficiency of very hydrophobic and amorphous PS treated for all strains tested and a strain-dependent efficiency with modified PP surface being very heterogeneous at the mesoscopic scale. Thus, these biological results pointed out not only the respective role of the surface chemistry and topography in bacterial adhesion, but also the dependence on the peaks and valley distribution at bacteria dimension scale.

Gangliosides and sialic acid effects upon newborn pathogenic bacteria adhesion: An in vitro study

The effect of the main gangliosides (GM1, GM3, GD3) and free sialic acid (Neu5Ac) upon the adhesion of pathogenic bacteria implicated in infant diarrhoea is assessed in vitro using the Caco-2 cell line. Concentrations of the bioactive compounds found in the bioaccessible (soluble) fraction of infant formula and human milk are employed. Bacterial adhesion behaviour included enterotoxigenic Escherichia coli (ETEC), enteropathogenic E.coli (EPEC), Listeria monocytogenes, Salmonella entericaserovartyphi, Shigella sonnei, Campylobacter jejuni and Helicobacter pylori. Three different approaches were assayed: pre-incubation of bacteria and compounds before addition to cells (competition); pre-incubation of the cells with compounds (exclusion); and pre-incubation of cells with bacteria (displacement). Furthermore, the spatial localization of the most abundant gangliosides, GM3 and GD3, in Caco-2 cells has been determined using confocal microscopy. Results show that GM3, GD3, GM1 and Neu5Ac at the assayed concentrations are able to interfere with the adhesion of several pathogenic bacteria involved in neonatal diseases-the greatest effect corresponding to Neu5Ac, followed by GD3, GM1 and GM3. Gangliosides GM3 and GD3 are located in the apical and basolateral membranes of the Caco-2 cells.

Adhesion to the yeast cell surface as a mechanism for trapping pathogenic bacteria by Saccharomyces probiotics

Recently, much attention has been given to the use of probiotics as an adjuvant for the prevention or treatment of gastrointestinal pathology. The great advantage of therapy with probiotics is that they have few side effects such as selection of resistant bacteria or disturbance of the intestinal microbiota, which occur when antibiotics are used. Adhesion of pathogenic bacteria onto the surface of probiotics instead of onto intestinal receptors could explain part of the probiotic effect. Thus, this study evaluated the adhesion of pathogenic bacteria onto the cell wall of Saccharomyces boulardii and Saccharomyces cerevisiae strains UFMG 905, W303 and BY4741. To understand the mechanism of adhesion of pathogens to yeast, cell-wall mutants of the parental strain of Saccharomyces cerevisiae BY4741 were used because of the difficulty of mutating polyploid yeast, as is the case for Saccharomyces cerevisiae and Saccharomyces boulardii. The tests of adhesion showed that, among 11 enteropathogenic bacteria tested, only Escherichia coli, Salmonella Typhimurium and Salmonella Typhi adhered to the surface of Saccharomyces boulardii, Saccharomyces cerevisiae UFMG 905 and Saccharomyces cerevisiae BY4741. The presence of mannose, and to some extent bile salts, inhibited this adhesion, which was not dependent on yeast viability. Among 44 cell-wall mutants of Saccharomyces cerevisiae BY4741, five lost the ability to fix the bacteria. Electron microscopy showed that the phenomenon of yeast-bacteria adhesion occurred both in vitro and in vivo (in the digestive tract of dixenic mice). In conclusion, some pathogenic bacteria were captured on the surface of Saccharomyces boulardii, Saccharomyces cerevisiae UFMG 905 and Saccharomyces cerevisiae BY4741, thus preventing their adhesion to specific receptors on the intestinal epithelium and their subsequent invasion of the host.

Retraction of enteropathogenic E. coli type IV pili promotes efficient host cell colonization, effector translocation and tight junction disruption

Type IV pili (Tfp) play a primary role in mediating the adherence of pathogenic bacteria to their hosts. The pilus filament can retract with an immense force. However, the role of this activity in microbial pathogenesis has not been rigorously explored. Experiments performed on volunteers suggested that the retraction capacity of enteropathogenic Escherichia coli (EPEC) Tfp is required for full virulence. Here we review our recent study1 in which we showed that the retraction capacity of the EPEC Tfp facilitates tight-junction disruption and actin-rich pedestal formation by promoting efficient bacterial protein effector translocation into epithelial host cells. We also present new data using live imaging confocal microscopy suggesting that EPEC adheres to monolayers in microcolonies and that Tfp retraction facilitates significant changes in the microcolony shape, which may be critical for efficient effector delivery. Our studies hence suggest novel insights into the role of pili retraction in EPEC pathogenesis.

Soluble Plantain Fibre Blocks Epithelial Adhesion and M-Cell Translocation of Intestinal Pathogens

Introduction Dietary fibres may have prebiotic effects mediated by promotion of probiotic bacteria. This study explores the possibility that they may also improve health by inhibiting epithelial adhesion and translocation by pathogenic bacteria. We have focussed on soluble non-starch polysaccharide (NSP) from plantain bananas ( Musa spp) since previous studies had shown that this is particularly effective at blocking Escherichia coli epithelial adherence. Methods The ability of plantain NSP to inhibit epithelial cell adhesion and invasion of various bacterial pathogens, their translocation through microfold (M)-cell monolayers (generated by co-culture of Caco2-cl1 cells and Raji B cells) and human Peyer9s patches mounted in Ussing chambers has been assessed. Results Plantain NSP showed dose-related inhibition of epithelial adhesion and M-cell translocation by a range of gut pathogens. Plantain NSP at 5 mg/ml, a concentration readily achievable in the human gut lumen, inhibited adhesion to Caco2 cells of Clostridium difficile (67.6±12.3%, p Salmonella typhimurium (85.0±8.2%, p Shigella sonnei (46.6±29.3%, p ETEC (56.1±23.67%, p Salmonella (80.2±9.7%) and Shigella (46.7±13.4%; both p 2 cells by plantain NSP was also confirmed by Giemsa stain and light microscopy. Plantain NSP, at 5 mg/ml, also inhibited translocation of Salmonella and Shigella across M-cells by 46% and 73% respectively (both P Salmonella translocation across follicle-associated epithelium (FAE) of human ileal Peyer9s patches was observed with 5 mg/ml plantain NSP (p Conclusion Soluble plant fibre from plantain bananas inhibits invasion and adhesion of pathogenic bacteria to Caco2 cells, and their translocation across M-cells of the FAE. This represents a novel mechanism by which soluble dietary fibres could promote intestinal health and prevent infective diarrhoea.

* Soluble plantain fibre blocks epithelial adhesion and M-cell translocation of intestinal pathogens

IntroductionDietary fibres may have prebiotic effects mediated by promotion of probiotic bacteria. This study explores the possibility that they may also improve health by inhibiting epithelial adhesion and translocation by...

Ability of Lactobacillus to inhibit enteric pathogenic bacteria adhesion on Caco-2 cells

The antagonistic effects of Lactobacillus against pathogenic bacteria were evaluated in vitro on cultured Caco-2 cells. Lactobacilli were added simultaneously with enteric pathogenic strains (enterotoxigenic Escherichia coli K88 or Salmonella typhimurium SARB21 and SL1344), before pathogenic strains and after pathogenic strains for competition, exclusion and displacement assays. The six lactobacilli significantly limited the adhesion and invasion of the pathogenic bacteria. In the simulating competition and exclusion assays, the adhesion of pathogenic strains was reduced by Lactobacillus strains significantly, whereas the inhibiting effect on pathogenic strains adhesion was a little weaker in the displacement assay. Furthermore, we found that the antagonistic effects of lactobacilli against K88, SARB21, and SL1344 were various. Strain R4 showed a strong inhibitory effect on the adhesion of K88 to Caco-2 cells. In the competition assay of R4, the number of viable cell-associated K88 (3.84 ± 0.10 log CFU/well) was much lower than the control group without Lactobacillus (5.98 ± 0.02 log CFU/well). Compared to the control group (6.07 ± 0.02 log CFU/well), the six Lactobacillus strains all performed strong antagonistic effects against SL1344, particularly D17 showed a higher inhibitory effect in the displacement assays (4.15 ± 0.04 log CFU/well). These results implied that several Lactobacillus strains might be useful for protecting against enteric pathogenic infection.

Effect of cranberry juice intake on human gut microbial community and urinary metabolites in a randomized, placebo‐controlled intervention

Cranberry polyphenols support health by reducing pathogenic bacteria adhesion and growth. This randomized, double‐blind, cross‐over pilot study compared effects of consuming a light 27% cranberry juice beverage(LCB) vs. a placebo beverage (LPB) on fecal microbial community and urine metabolites. Healthy subjects(n=5), 20–40 y, received 480 ml/d LPB or LCB in two 6‐wk intervention periods, with a 1 mth washout. Fecal samples were collected at baseline, 3 and 6 wk and 24h urine at baseline and 6 wk. Microbial community structure, measured by terminal restriction fragment length polymorphism and quantitative PCR (QPCR) of the 16S rRNA gene, differed significantly (MRBP; p=0.036) between treatments at 6 wks. Bifidobacteria(as % of total Eubacteria) significantly increased when subjects received the LCB (F= 6.19, p<0.015)with no significant effect on Bacterodetes, Lactobacillus sp., Enterobacteria, or C. coccoides/E.rectale groups (by qPCR and adjusted for period effect). LCB intake significantly changed 49 urine metabolites, notably of nucleotide metabolism, and potential intake biomarkers, including protocatechuic acid‐3‐glucoside (Metabolon, Inc, NC) to help guide cranberry health research. The results suggest that cranberry juice intake may modulate human gut microbial community without decreasing percentages of some beneficial commensal bacteria. Supported by Ocean Spray Cranberries, Inc.

Anti-adhesion activity of two biosurfactants produced by Bacillus spp. prevents biofilm formation of human bacterial pathogens

In this work, two biosurfactant-producing strains, Bacillus subtilis and Bacillus licheniformis, have been characterized. Both strains were able to grow at high salinity conditions and produce biosurfactants up to 10% NaCl. Both extracted-enriched biosurfactants showed good surface tension reduction of water, from 72 to 26-30 mN/m, low critical micelle concentration, and high resistance to pH and salinity. The potential of the two lipopeptide biosurfactants at inhibiting biofilm adhesion of pathogenic bacteria was demonstrated by using the MBEC device. The two biosurfactants showed interesting specific anti-adhesion activity being able to inhibit selectively biofilm formation of two pathogenic strains. In particular, Escherichia coli CFT073 and Staphylococcus aureus ATCC 29213 biofilm formation was decreased of 97% and 90%, respectively. The V9T14 biosurfactant active on the Gram-negative strain was ineffective against the Gram-positive and the opposite for the V19T21. This activity was observed either by coating the polystyrene surface or by adding the biosurfactant to the inoculum. Two fractions from each purified biosurfactant, obtained by flash chromatography, fractions (I) and (II), showed that fraction (II), belonging to fengycin-like family, was responsible for the anti-adhesion activity against biofilm of both strains.

Electrospun Non‐Woven Nanofibrous Hybrid Mats Based on Chitosan and PLA for Wound‐Dressing Applications

Continuous defect-free nanofibers containing chitosan (Ch) or quaternized chitosan (QCh) were successfully prepared by one-step electrospinning of Ch or QCh solutions mixed with poly[(L-lactide)-co-(D,L-lactide)] in common solvent. XPS revealed the surface chemical composition of the bicomponent electrospun mats. Crosslinked Ch- and QCh-containing nanofibers exhibited higher kill rates against bacteria S. aureus and E. coli than the corresponding solvent-cast films. SEM observations showed that hybrid mats were very effective in suppressing the adhesion of pathogenic bacteria S. aureus. The hybrid nanofibers are promising for wound-healing applications.

Prevention of Intestinal Infection by Glycomacropeptide

The preventive effects of glycomacropeptide (GMP) against intestinal infection were investigated, and conjugates of GMP with xylooligosaccharide (XOS) and carboxymethyldextran (CMD) were prepared by the Maillard reaction to enhance the effect of GMP. The binding ability of GMP to intestinal pathogenic bacteria was evaluated by a binding assay with biotinylated bacteria. GMP showed the ability to bind to Salmonella enteritidis and enterohemorrhagic Escherichia coli O157:H7 (EHEC O157). This binding ability was decreased by a sialidase treatment and completely eliminated by periodate oxidation. These results indicate that such carbohydrate moieties as sialic acid in GMP are involved in binding to S. enteritidis and EHEC O157. The preventive effect of GMP on the adhesion of pathogenic bacteria to Caco-2 cells was also investigated. GMP showed an inhibitory effect on the adhesion of EHEC O157 in a dose-dependent manner, although it was not a potent inhibitor of the adhesion of Salmonella infection. However, in the case of Salmonella infection, GMP-XOS and GMP-CMD significantly suppressed IL-8 production which was the index of infection. Our results indicate GMP to be a promising agent for preventing intestinal infection.

Measurement of bacterial adhesion—in vitro evaluation of different methods

The adhesion of bacteria to host tissue is the first step in pathogenesis. Similarly, bacterial adhesion to inanimate surfaces is the first step in formation of biofilms—a real problem in industrial processes and medical devices. Various agents capable of blocking the adhesion of bacteria to surfaces have been identified, such as probiotics, which are supposed to prevent the adhesion of pathogenic bacteria to the intestinal mucosa. Although measurement of bacterial adhesion is important itself, especially when agents used to prevent adhesion are developed, a relative small number of techniques can be used in the measurement of adhesion. These techniques are not well validated and there is lack of studies where those methods are compared to each other. Here we have compared different commonly used methods to measure adhesion of bacteria; radioactive labelling, fluorescence tagging, and staining of bacteria. The methods were used to measure the adhesion of Escherichia coli and Salmonella enterica serovar Typhimurium to intestinal mucus. Moreover, selected probiotic strains were used to study whether probiotics or the adhesion method used affected the results. As a result, we show that the best reproducibility and sensitivity were obtained using radioactive labelling. With other methods, the sensitivity was too low due to poorly adhering bacteria and low signal-to-background ratio.

A Human Flora‐Associated Rat Model of the Breast‐Fed Infant Gut

ABSTRACTObjectivesBacterial colonization of the infant gut may have important influences on the development of gastrointestinal, respiratory, and allergic disease. Early diet is a major determinant of the gut microflora. It is very difficult to carry out studies in human infants that can investigate the interaction of diet, flora, and mucosa. In this study we have developed an infant human flora‐associated (IHFA) rat model to allow such investigation.MethodsGerm‐free infant rats were infected with fecal bacteria from exclusively breast‐fed infants and were maintained on a modified infant formula for 8 weeks. The fecal and cecal contents were collected and compared with feces of breast‐fed infants for bacterial populations, bacterial metabolites, and enzymes and for the ability to inhibit adhesion of pathogenic bacteria to human mucosal cells.ResultsThe IHFA cecum and feces were dominated by lactic acid bacteria, Bifidobacterium, and lactobacilli, which were representative of the infant feces. The fecal short‐chain fatty acid profile was dominated by acetic and lactic acid in a similar manner to human infant feces. Other bacterial metabolites were similar to those of the human infant. Rat intestinal samples were able to inhibit the adhesion of pathogens to mucosal cells, but to a lesser extent than the human samples.ConclusionsThis IHFA infant model of the intestinal flora of the breast‐fed infant is considered valid for studying the effect of diet on bacterial colonization and metabolism.

A human flora-associated rat model of the breast-fed infant gut.

Bacterial colonization of the infant gut may have important influences on the development of gastrointestinal, respiratory, and allergic disease. Early diet is a major determinant of the gut microflora. It is very difficult to carry out studies in human infants that can investigate the interaction of diet, flora, and mucosa. In this study we have developed an infant human flora-associated (IHFA) rat model to allow such investigation. Germ-free infant rats were infected with fecal bacteria from exclusively breast-fed infants and were maintained on a modified infant formula for 8 weeks. The fecal and cecal contents were collected and compared with feces of breast-fed infants for bacterial populations, bacterial metabolites, and enzymes and for the ability to inhibit adhesion of pathogenic bacteria to human mucosal cells. The IHFA cecum and feces were dominated by lactic acid bacteria, Bifidobacterium, and lactobacilli, which were representative of the infant feces. The fecal short-chain fatty acid profile was dominated by acetic and lactic acid in a similar manner to human infant feces. Other bacterial metabolites were similar to those of the human infant. Rat intestinal samples were able to inhibit the adhesion of pathogens to mucosal cells, but to a lesser extent than the human samples. This IHFA infant model of the intestinal flora of the breast-fed infant is considered valid for studying the effect of diet on bacterial colonization and metabolism.

Antigenic characterization of fimbria preparations from Streptococcus mutans isolates from caries-free and caries-susceptible subjects.

The adhesion of pathogenic bacteria to the host surface is an essential step in the development of numerous infections, including dental caries. Attachment of Streptococcus mutans, the main etiological agent of human dental caries, to the tooth surface may be mediated by glucan synthesized by glucosyltransferase (GTF) and by cell surface proteins, such as P1, which bind to salivary receptors. Fimbriae on the surfaces of many microorganisms are known to function in bacterial adhesion. Previous studies in this laboratory have initially characterized the fibrillar surface of S. mutans. The purpose of this investigation was the comparison of the antigenic properties of fimbria preparations of S. mutans isolates from five caries-resistant (CR) and six caries-susceptible (CS) subjects. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of S. mutans fimbrial preparations revealed five major protein bands at 200, 175, 157, 86, and 66 kDa in preparations from CR and CS subjects. Immunoblot analysis indicated the presence of the same major bands recognized by anti-S. mutans fimbria antisera. Furthermore, the 175- and 157-kDa bands were recognized by antibodies to P1 and GTF, respectively. Immunoblot analysis with antisera to the fimbria preparation, to P1, or to GTF indicated that the levels of fimbria-reactive components and P1 and GTF antigens were higher in S. mutans fimbria preparations from CS subjects than in those from CR individuals. For example, four of six fimbria preparations from CS patients had demonstrable P1, and all had GTF. In contrast, only two of five CR fimbrial preparations exhibited P1 and GTF. Enzyme-linked immunosorbent assay demonstrated similar results for levels of GTF antigen in the fimbrial preparations from CR and CS subjects. The results suggest that differences between the compositions of S. mutans fimbriae in CR and CS individuals may play an important role in the virulence of this microorganism in dental caries.

Use of carbohydrates and peptides in studies of adhesion of pathogenic bacteria and in efforts to generate carbohydrate-specific T cells

Abstract

Localization of the Fusobacterium nucleatum T18 adhesin activity mediating coaggregation with Porphyromonas gingivalis T22.

Adherence of pathogenic bacteria is often an essential first step in the infectious process. The ability of bacteria to adhere to one another, or to coaggregate, may be an important factor in their ability to colonize and function as pathogens in the periodontal pocket. Previously, a strong and specific coaggregation was demonstrated between two putative periodontal pathogens, Fusobacterium nucleatum and Porphyromonas gingivalis. The interaction appeared to be mediated by a protein adhesin on the F. nucleatum cells and a carbohydrate receptor on the P. gingivalis cells. In this investigation, we have localized the adhesin activity of F. nucleatum T18 to the outer membrane on the basis of the ability of F. nucleatum T18 vesicles to coaggregate with whole cells of P. gingivalis T22 and the ability of the outer membrane fraction of F. nucleatum T18 to inhibit coaggregation between whole cells of F. nucleatum T18 and P. gingivalis T22. Proteolytic pretreatment of the F. nucleatum T18 outer membrane fraction resulted in a loss of coaggregation inhibition, confirming the proteinaceous nature of the adhesin. The F. nucleatum T18 outer membrane fraction was found to be enriched for several proteins, including a 42-kDa major outer membrane protein which appeared to be exposed on the bacterial cell surface. Fab fragments prepared from antiserum raised to the 42-kDa outer membrane protein were found to partially but specifically block coaggregation. These data support the conclusion that the 42-kDa major outer membrane protein of F. nucleatum T18 plays a role in mediating coaggregation with P. gingivalis T22.

Adhesion of bacteria to mucosal surfaces--an area of increasing importance in diarrhoeal disease.

The study of the adhesive interactions between host and microorganisms is likely to have major repercussions in many aspects of the study of infectious diseases. In the field of bacterial diarrhoea, it has already been shown that the ability to adhere to the brush border of the intestinal mucosa is an essential pre-requisite to colonisation of the intestine, thus initiating the chain of events leading to proliferation, enterotoxin production, small-intestinal secretion, and overt diarrhoea. The interruption of this chain of events by a new generation of therapeutic agents which act by inhibiting the adhesion of pathogenic bacteria, or by rendering them non-adhesive with specific IgA, will usher in a new era in the treatment of diarrhoeal disease.