scholarly journals Enterococcus faecalis strains show culture heterogeneity in cell surface charge

Microbiology ◽  
2006 ◽  
Vol 152 (3) ◽  
pp. 807-814 ◽  
Author(s):  
Annet E. J. van Merode ◽  
Henny C. van der Mei ◽  
Henk J. Busscher ◽  
Karola Waar ◽  
Bastiaan P. Krom
Keyword(s):  
Zeta Potential ◽  
Cell Surface ◽  
Enterococcus Faecalis ◽  
Ph Dependence ◽  
Cell Surface Hydrophobicity ◽  
Surface Protein ◽  
Opportunistic Pathogen ◽  
Surface Hydrophobicity ◽  
Biliary Stents ◽  
Abiotic Surfaces

Adhesion of micro-organisms to biotic and abiotic surfaces is an important virulence factor and involves different types of interactions. Enterococcus faecalis, a human commensal and an important opportunistic pathogen, has the ability to adhere to surfaces. Biliary stents frequently become clogged with bacterial biofilms, with E. faecalis as one of the predominant species. Six E. faecalis strains isolated from clogged biliary stents were investigated for the presence of specific biochemical factors involved in their adhesion: aggregation substances (Aggs) and the enterococcal surface protein (encoded by the esp gene). In addition, physico-chemical factors involved in adhesion (zeta potential and cell surface hydrophobicity) were determined, as well as the influence of ox bile on these properties. Two-thirds of the biliary stent isolates displayed culture heterogeneity in the pH dependence of their zeta potentials. Moreover, 24 out of 46 clinical isolates of E. faecalis, including 11 laboratory strains, also displayed such heterogeneity. The culture heterogeneity was demonstrated to be a stable trait, not caused by quorum sensing, not plasmid mediated, and independent of the presence of esp and Agg. Data presented show that culture heterogeneity in zeta potential enhances adhesion to an abiotic surface. A higher prevalence of culture heterogeneity in zeta potential in pathogenic as compared to non-pathogenic isolates could indicate that this phenomenon might play a role in virulence and putatively in pathogenesis.

scholarly journals Characterization of Monolaurin Resistance in Enterococcus faecalis

2007 ◽  
Vol 73 (17) ◽  
pp. 5507-5515 ◽  
Author(s):  
Muriel Dufour ◽  
Janet M. Manson ◽  
Philip J. Bremer ◽  
Jean-Pierre Dufour ◽  
Gregory M. Cook ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Surface ◽  
Enterococcus Faecalis ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Wall Structure ◽  
Transmission Electron ◽  
Serious Infections ◽  
Autolytic Activity

ABSTRACT There is increasing concern regarding the presence of vancomycin-resistant enterococci in domestically farmed animals, which may act as reservoirs and vehicles of transmission for drug-resistant enterococci to humans, resulting in serious infections. In order to assess the potential for the use of monolaurin as a food preservative, it is important to understand both its target and potential mechanisms of resistance. A Tn917 mutant library of Enterococcus faecalis AR01/DGVS was screened for resistance (MIC, >100 μg/ml) to monolaurin. Three mutants were identified as resistant to monolaurin and were designated DGRM2, DGRM5, and DGRM12. The gene interrupted in all three mutants was identified as traB, which encodes an E. faecalis pheromone shutdown protein and whose complementation in trans restored monolaurin sensitivity in all three mutants. DGRM2 was selected for further characterization. E. faecalis DGRM2 showed increased resistance to gentamicin and chloramphenicol (inhibitors of protein synthesis), while no difference in the MIC was observed with the cell wall-active antibiotics penicillin and vancomycin. E. faecalis AR01/DGVS and DGRM2 were shown to have similar rates (30% cell lysis after 4 h) of cell autolytic activity when activated by monolaurin. Differences in cell surface hydrophobicity were observed between the wild type and the mutant, with the cell surface of the parent strain being significantly more hydrophobic. Analysis of the cell wall structure of DGRM2 by transmission electron microscopy revealed an increase in the apparent cell wall thickness and contraction of its cytoplasm. Taken together, these results suggest that the increased resistance of DGRM2 was due to a change in cell surface hydrophobicity, consequently limiting the diffusion of monolaurin to a potential target in the cytoplasmic membrane and/or cytoplasm of E. faecalis.

scholarly journals Analysis of Functional Domains of theEnterococcus faecalis Pheromone-Induced Surface Protein Aggregation Substance

2001 ◽  
Vol 183 (19) ◽  
pp. 5659-5667 ◽  
Author(s):  
C. M. Waters ◽  
G. M. Dunny
Keyword(s):  
Cell Surface ◽  
High Efficiency ◽  
Cell Surface Hydrophobicity ◽  
Surface Protein ◽  
Cell Aggregation ◽  
Surface Hydrophobicity ◽  
Host Cells ◽  
Functional Domains ◽  
Aggregation Substance ◽  
C Terminus

ABSTRACT Pheromone-inducible aggregation substance (AS) proteins ofEnterococcus faecalis are essential for high-efficiency conjugation of the sex pheromone plasmids and also serve as virulence factors during host infection. A number of different functions have been attributed to AS in addition to bacterial cell aggregation, including adhesion to host cells, adhesion to fibrin, increased cell surface hydrophobicity, resistance to killing by polymorphonuclear leukocytes and macrophages, and increased vegetation size in an experimental endocarditis model. Relatively little information is available regarding the structure-activity relationship of AS. To identify functional domains, a library of 23 nonpolar 31-amino-acid insertions was constructed in Asc10, the AS encoded by the plasmid pCF10, using the transposons TnlacZ/in and TnphoA/in. Analysis of these insertions revealed a domain necessary for donor-recipient aggregation that extends further into the amino terminus of the protein than previously reported. In addition, insertions in the C terminus of the protein also reduced aggregation. As expected, the ability to aggregate correlates with efficient plasmid transfer. The results also indicated that an increase in cell surface hydrophobicity resulting from AS expression is not sufficient to mediate bacterial aggregation.

Zeta Potential Aspects of Dispersed Solvents Involved in the Determination of Microbial Cell Surface Hydrophobicity

2006 ◽  
Vol 27 (1) ◽  
pp. 23-32 ◽  
Author(s):  
A. Gallardo‐Moreno ◽  
R. Calzado‐Montero ◽  
M. González‐Martín ◽  
C. Pérez‐Giraldo
Keyword(s):  
Zeta Potential ◽  
Cell Surface ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Microbial Cell

Antibiofilm and antivirulence effect of stilbenes on clinically relevant staphylococci

2020 ◽  
Author(s):  
Petra Kašparová ◽  
Olga Maťátková
Keyword(s):  
Cell Surface ◽  
Biofilm Formation ◽  
Pathogenic Bacteria ◽  
Wide Spectrum ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Antibiofilm Activity ◽  
Host Immune System ◽  
Abiotic Surfaces ◽  
Antibiotic Compounds

<p>Genus <em>Staphylococcus</em> comprises many greatly pathogenic species like <em>S. aureus</em>, <em>S. epidermidis</em> or <em>S. saprophyticus</em>. The great pathogenicity of stated species is often facilitated by their capability to form thick complex biofilms on various biotic or abiotic surfaces. Biofilm formation together with extracellular hydrolases or toxins represents important virulence factor, which increases persistence of staphylococci in host via enhancing their ability to evade host immune system and further promote the infection development. With an increased emergence of antibiotic resistance among pathogenic bacteria including staphylococci the search for novel antibiotic compounds with antivirulence effect is sought. Such substances might be stilbenes, phenolic compounds isolated from various plants (<em>Vitis</em> spp., <em>Vaccinium</em> spp., <em>Pterocarpus</em> spp., <em>Pinus</em> spp.). They possess strong antioxidant activity and a wide spectrum of beneficial pharmacological effects (antitumor, hypolipidemic, hypoglycemic). Apart from that, they also have great antimicrobial activity with a potent ability to enhance antibiotics action in combination.</p> <p>Presented work focused on resveratrol, pterostilbene (PTE) and pinosylvine and their effect on <em>S. aureus</em> and <em>S. epidermidis</em> biofilm formation. The effect of stilbene representatives on production of other virulence factors (proteases, phospholipases, haemolysins), cell surface hydrophobicity and morphology was also observed.</p> <p>PTE was found to be the most effective among studied stilbenes against <em>S. aureus</em> and <em>S. epidermidis</em> biofilm with minimum biofilm inhibitory concentrations (MBIC<sub>80</sub>) ranging from 40 to 130 mg/l. Its effect on mature staphylococcal biofilm eradication was even greater with 80% eradication rate achieved by 40-75 mg/l. PTE (49 mg/l) was found to have a potent combinatory antibiofilm activity with erythromycin or tetracycline (5 mg/l both) causing more than 80% inhibition in metabolic activity of biofilm cells. It was able to permeabilize cytoplasmic membrane, thus probably enabling antibiotic uptake by the cell. PTE also altered cell surface hydrophobicity and production of haemolysin.</p> <p>PTE might be the solution to increasing biofilm-related resistance problem and a promising candidate with antibiofilm and antivirulence potential for future antibiotic treatment of staphylococcal infections.</p> <p> </p> <p><em>This work was supported by the grant of Specific university research – grant No. A2_FPBT_2020_004.</em></p>

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