Plasmid-associated hemolysin and aggregation substance production contribute to virulence in experimental enterococcal endocarditis

Chow, Joseph W.; Thal, L A; Perri, Mary Beth; Vázquez, Julio; Donabedian, Susan; Clewell, Don B.; Zervos, M. J.

doi:10.1128/aac.37.11.2474

Cited by 295 publications

(244 citation statements)

References 23 publications

Supporting

Mentioning

227

Contrasting

Unclassified

Order By: Relevance

“…E. faecalis strains isolated from the faeces of healthy volunteers, liver transplant patients and blood cultures have been described and characterized for the presence of Esp and Agg elsewhere (Waar et al, 2002a). The enterococcal laboratory strains used in this study were: E. faecalis JH2-2 (Jacob & Hobbs, 1974), OG1X (Ike et al, 1983), OG1X(pAD1) (Clewell et al, 1982), OG1XE(pAD1) (Muscholl et al, 1993), OG1X(pAM373) (Clewell et al, 1985), FA2-2 (Clewell et al, 1982), FA2-2(pAD1) (Chow et al, 1993), MMH594 (Shankar et al, 1999), MMH594b (Shankar et al, 2001b), OG1RF (Dunny et al, 1978) and OG1RF(pCF10) (Dunny et al, 1981). All isolates were cultured from frozen stock on blood agar plates.…”

Section: Methodsmentioning

confidence: 99%

Enterococcus faecalis strains show culture heterogeneity in cell surface charge

et al. 2006

View full text Add to dashboard Cite

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.

show abstract

Section: Methodsmentioning

confidence: 99%

Enterococcus faecalis strains show culture heterogeneity in cell surface charge

et al. 2006

View full text Add to dashboard Cite

show abstract

“…Some indirect evidence for this stems from the fact that for one and the same adhesin ASAl different results regarding binding to eukaryotic cells were observed. Chow et al (1993) (Berti et al, unpublished), using a rat endocarditis model, indicated that the presence or absence of the asal gene did not alter establishment of E. faecalis. The differences observed in those two studies could well be attributed to differences in the eukaryotic receptors ; however, other explanations cannot be excluded at the moment.…”

Section: Interaction With Bacterial and Eukaryotic Cellsmentioning

confidence: 99%

The sex pheromone system of Enterococcus faecalis

Wirth¹

1994

European Journal of Biochemistry

120

View full text Add to dashboard Cite

The sex pheromone system of Enterococcus faecalis was discovered by observing a clumping reaction of E. faecalis strains during conjugative transfer of plasmids. It was found that only a special type of E. faecalis plasmids, the so-called sex pheromone plasmids, are transferred via this mechanism. Various experiments, especially by the group of D. B. Clewell, led to the formulation of a model describing how the sex pheromone system works. Small linear peptides, the so-called sex pheromones, are excreted by strains not possessing the corresponding sex pheromone plasmid. Donor strains harboring the plasmid do not produce the corresponding sex pheromone; they react to the presence of the peptide by production of a plasmid-encoded adhesin, the so-called aggregation substance. This adhesin allows contact between the non-motile mating partners ; after conjugative transfer of the plasmid, the former recipient possesses and replicates the new plasmid. Thereby the population of E. faecalis strains is shifted to a high percentage of donor strains. This is especially true because a donor strain will still excrete sex pheromones corresponding to plasmids it does not harbor; therefore, such a strain can also function as recipient for other sex pheromone plasmids it does not possess.Various aspects of this unique plasmid collection mechanism have been studied during the last few years. The data indicate that, with the exception of pAM373, all sex pheromone plasmids possess one DNA region which is highly similar to and codes for the adhesin. It is also becoming more and more clear that regulatory functions/proteins are not conserved between different sex pheromone plasmids. Induction of adhesin synthesis needs the action of a regulatory cascade composed of unique features; at the moment we are just beginning to understand this cascade. By sequencing the first structural gene for one of those adhesins, we realized that the aggregation substance might act also as an adhesin for eucaryotic cells, probably by interaction with integrins. At least in the case of the in vitro cultured pig kidney tubulus cell line LLC-PK, this idea could be verified. An interesting aspect of the sex pheromone system of E. faecalis is its evolution. I will discuss the idea that two different components, both of which well might contribute to virulence of the opportunistic pathogenic bacterium, were combined in the species E. faecalis to result in this unique plasmid collection system.Enterococcus faecalis belongs to the bacterial genus Enterococcus which at the moment contains more than 15 valid species. The genus was established in 1984 when 'Streptococcus faecalis' and 'Streptococcus faecium' were transferred from the taxionomically unclearly defined group 'Streptococcus' in the new genus (Schleifer and Kilpper-Balz, 1984). Because of this some of the older literature cited in Abbreviations. ASA1, ASA373, ASCIO and ASPl, aggregation substance encoded by sex pheromone plasmids pAD1, pAM373, pCFlO and pPD1, respectively; ORFX, gene product of ogx (or€ ...

show abstract

“…Cytolysin enhances the virulence of Enterococcus faecalis in animal models, such as murine peritonitis and rabbit endophthalmitis (Ike et al, 1984;Jett et al, 1992;Chow et al, 1993;Jett et al, 1994). Other factors include aggregation substance, which is a pheromone-inducible surface protein of E. faecalis and promotes mating aggregate formation during bacterial conjugation (Clewell, 1993).…”

Section: Introductionmentioning

confidence: 99%

Production of enterolysin A by a raw milk enterococcal isolate exhibiting multiple virulence factors

et al. 2003

View full text Add to dashboard Cite

Even though enterococci are a common cause of human infection they can readily be isolated from a range of food sources, including various meat and dairy products. An enterococcal strain, DPC5280, which exhibits a broad spectrum of inhibition against many Gram-positive bacteria was recently isolated from an Irish raw milk sample. Characterization of the inhibition revealed that the strain exhibits haemolytic activity characteristic of the two-component lantibiotic cytolysin and also produces a heat-labile antimicrobial protein of 34 kDa. The latter protein displayed cell wall hydrolytic activity, as evidenced by zymogram gels containing autoclaved lactococcal cells. N-terminal sequencing of the purified protein yielded the sequence ASNEWS which is 100 % identical to enterolysin A (accession no. AF249740), a protein which shares 28 and 29 % identity to the Gly-Gly endopeptidases, lysostaphin and zoocin A, respectively. Indeed, amplification of entL from DPC5280 and sequencing revealed that the protein is 100 % identical to enterolysin A. The DPC5280 strain also contained the determinants associated with multiple virulence factors, including gelatinase, aggregation substance and multiple antibiotic resistance. The linkage of this cell-wall-degrading enzyme to other virulence factors in enterococci may contribute to the competitiveness of pathogenic enterococci when found in complex microbial environments such as food and the gastrointestinal tract. INTRODUCTIONDespite the fact that foods containing enterococci have a long history of safe use, these organisms are not considered as GRAS (generally recognized as safe) organisms. They can readily be isolated from a range of food sources, including raw milk, and are often a constituent of some mixed starter strains used commercially. However, many strains can act as opportunistic pathogens, causing a variety of infections such as urinary tract infections, bacteremia and infective endocarditis (Murray, 1990;Jett et al., 1994), and are of major importance in community-acquired and in hospital-acquired (nosocomial) infections (Jett et al., 1994;Low et al., 1994;Jones et al., 1997;Simjee & Gill, 1997). A contributing factor to their pathogenesis is their evolving resistance to antibiotics. For example, resistance to the antibiotic vancomycin is now widespread among members of the genus, which leaves few options for disease management (Aguirre & Collins, 1993;Knudtson & Hartman, 1993;Facklam & Sahm, 1995;Klein et al., 1998). Considerable progress has recently been made in determining the traits responsible for pathogenesis of enterococci.For example, studies have shown that phenotypes such as production of cytolysin, which has both haemolytic activity (by lysing a broad spectrum of cells, including human, horse and rabbit erythrocytes) and bactericidal activity (against Gram-positive bacteria) play a role in the progression of enterococcal infection (Ike et al., 1984;Jett et al., 1992). Cytolysin enhances the virulence of Enterococcus faecalis in animal models, such as muri...

show abstract

Plasmid-associated hemolysin and aggregation substance production contribute to virulence in experimental enterococcal endocarditis

Cited by 295 publications

References 23 publications

Enterococcus faecalis strains show culture heterogeneity in cell surface charge

Enterococcus faecalis strains show culture heterogeneity in cell surface charge

The sex pheromone system of Enterococcus faecalis

Production of enterolysin A by a raw milk enterococcal isolate exhibiting multiple virulence factors

Contact Info

Product

Resources

About