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PubMed2006

[Meningitis caused by Enterococcus faecalis during disseminated anguilluliasis].

INTRODUCTION: Disseminated anguilluliasis is a serious disease requiring early diagnosis and treatment. The occurrence of bacterial complications, especially meningeal, is generally due to Gram-negative bacteria from the gastrointestinal tract. CASE: A 52-year-old man from Guadeloupe, treated for T-lymphoma during the previous year by polychemotherapy, was hospitalized for meningitis. Culture of the cerebrospinal fluid and the bronchoalveolar lavage both showed Enterococcus faecalis. Strongyloides stercoralis were also found in the stool and bronchoalveolar lavage. Outcome under treatment was favorable. DISCUSSION: This case reminds us of the usefulness of presumptive routine ivermectin treatment for all patients exposed to any immunosuppression treatment and ever having lived in a tropical area and thus possibly infected by chronic but silent anguilluliasis, even in the absence of parasitological certainty.

Amoxicillin↗

PubMed2005

IL-10 gene-deficient mice lack TGF-beta/Smad signaling and fail to inhibit proinflammatory gene expression in intestinal epithelial cells after the colonization with colitogenic Enterococcus faecalis.

Nonpathogenic enteric bacterial species initiate and perpetuate experimental colitis in IL-10 gene-deficient mice (IL-10(-/-)). Bacteria-specific effects on the epithelium are difficult to dissect due to the complex nature of the gut microflora. We showed that IL-10(-/-) mice compared with wild-type mice fail to inhibit proinflammatory gene expression in native intestinal epithelial cells (IEC) after the colonization with colitogenic Gram-positive Enterococcus faecalis. Interestingly, proinflammatory gene expression was transient after 1 wk of E. faecalis monoassociation in IEC from wild-type mice, but persisted after 14 wk of bacterial colonization in IL-10(-/-) mice. Accordingly, wild-type IEC expressed phosphorylated NF-kappaB subunit RelA (p65) and phosphorylated Smad2 only at day 7 after bacterial colonization, whereas E. faecalis-monoassociated IL-10(-/-) mice triggered persistent RelA, but no Smad2 phosphorylation in IEC at days 3, 7, 14, and 28. Consistent with the induction of TLR2-mediated RelA phosphorylation and proinflammatory gene expression in E. faecalis-stimulated cell lines, TLR2 protein expression was absent after day 7 from E. faecalis-monoassociated wild-type mice, but persisted in IL-10(-/-) IEC. Of note, TGF-beta1-activated Smad signaling was associated with the loss of TLR2 protein expression and the inhibition of NF-kappaB-dependent gene expression in IEC lines. In conclusion, E. faecalis-monoassociated IL-10(-/-), but not wild-type mice lack protective TGF-beta/Smad signaling and fail to inhibit TLR2-mediated proinflammatory gene expression in the intestinal epithelium, suggesting a critical role for IL-10 and TGF-beta in maintaining normal epithelial cell homeostasis in the interplay with commensal enteric bacteria.

Animals↗

PubMed1995

Evaluation of therapeutic measures for treating endophthalmitis caused by isogenic toxin-producing and toxin-nonproducing Enterococcus faecalis strains.

PURPOSE: Management of endophthalmitis typically includes antibiotic combinations to arrest bacterial growth and antiinflammatory agents to limit inflammatory damage to sensitive tissues. Little research has been reported that systematically evaluates the contribution of each therapeutic component for treating infections caused by organisms of varying virulence. The authors determined the relative value of the antinflammatory corticosteroid, dexamethasone, as an intravitreal therapeutic adjunct for the treatment of infection caused by either Enterococcus faecalis expressing a cytolytic toxin previously shown to contribute to the course and severity of infection, or an otherwise identical strain of E. faecalis specifically attenuated in expression of the cytolytic toxin. METHODS: Endophthalmitis in rabbits was monitored using electroretinography (ERG). Eyes were infected with 100 colony forming units of either the cytolytic or the noncytolytic E. faecalis strain. Intravitreal ampicillin and gentamicin were administered at postinfection day 1, and intravitreal dexamethasone was either omitted or administered at day -1, 1, or 1.5. RESULTS: ERG B-wave amplitude declined precipitously throughout the course of infection with cytolytic toxin-producing E. faecalis, despite the administration of antibiotics and regardless of the time of dexamethasone administration. In fact, the ultimate course of infection caused by cytolytic E. faecalis did not differ from the course in untreated controls. In contrast, infections caused by specifically attenuated, noncytolytic strains of E. faecalis responded well to antibiotics augmented by antiinflammatory therapy when the latter was administered either 1 or 1.5 days after the initiation of infection. In these cases, no loss in ERG B-wave response was observed. CONCLUSIONS: These results underscore the importance of bacterial toxins in infectious diseases of the eye and their contribution to treatment failures. These results further suggest that in cases of endophthalmitis caused by toxin producing bacteria, significant improvement in clinical outcome will require specific therapeutic targeting of the toxins involved.

Ampicillin↗

PubMed2003

Intergeneric transfer of the Enterococcus faecalis plasmid pIP501 to Escherichia coli and Streptomyces lividans and sequence analysis of its tra region.

The nucleotide sequence of the transfer (tra) region of the multiresistance broad-host-range Inc18 plasmid pIP501 was completed. The 8629-bp DNA sequence encodes 10 open reading frames (orf), 9 of them are possibly involved in pIP501 conjugative transfer. The putative pIP501 tra gene products show highest similarity to the respective ORFs of the conjugative Enterococcus faecalis plasmids pRE25 and pAMbeta1, and the Streptococcus pyogenes plasmid pSM19035, respectively. ORF7 and ORF10 encode putative homologues of type IV secretion systems involved in transport of effector molecules from pathogens to host cells and in conjugative plasmid transfer in Gram-negative (G-) bacteria. pIP501 mobilized non-selftransmissible plasmids such as pMV158 between different E. faecalis strains and from E. faecalis to Bacillus subtilis. Evidence for the very broad-host-range of pIP501 was obtained by intergeneric conjugative transfer of pIP501 to a multicellular Gram-positive (G+) bacterium, Streptomyces lividans, and to G- Escherichia coli. We proved for the first time pIP501 replication, expression of its antibiotic resistance genes as well as functionality of the pIP501 tra genes in S. lividans and E. coli.

Base Sequence↗

PubMed1997

Antibacterial activity of calcium hydroxide-containing endodontic sealers on Enterococcus faecalis in vitro.

Antimicrobial activity of endodontic sealers is an important factor in the prognosis of root canal treatment. The aim of this study was to analyse the antimicrobial activity of calcium hydroxide-containing endodontic sealers, Sealapex (SA) and CRCS compared to a ZOE-containing sealer, Roth's cement. The sealers were mixed and placed on the side wall of microtitre plate wells. A 10 microL suspension of Enterococcus faecalis was added to the surface of the sealers 1 h, 24 h, or 7 days after mixture. Bacteria were allowed to come into contact with the sealers for 1 h at 37 degrees C. Fresh media was then added and bacterial growth was measured every 30 min for 16 h. The results showed that in 1-hour-old mixture, CRCS and Roth's cement had a significantly better antimicrobial effect than SA. In 24-hour-old mixtures, ZOE-based sealer showed a more potent antimicrobial activity than calcium hydroxide-containing sealers, whereas SA showed a significantly better antimicrobial effect in the 7-day-old mixture. The antimicrobial activity of each tested sealer changes differently with the time interval between mixing and testing, suggesting different physicochemical properties and potentially diverse clinical applications.

Calcium Hydroxide↗

PubMed2003

Antimicrobial resistance in Enterococcus faecalis at a tertiary care centre of northern India.

BACKGROUND & OBJECTIVES: Multiresistant enterococci are emerging as a leading nosocomial pathogen. Knowledge of the profile of antimicrobial resistance is essential to formulate treatment guidelines for infections caused by enterococci. This study reports the antimicrobial sensitivity of enterococci isolated during a one year period from clinical samples of patients admitted to a teriary care hospital of Delhi. METHODS: A total of 444 isolates of Enterococcus faecalis were screened for antimicrobial susceptibility by the disk diffusion technique as recommended by the National Committee for Clinical Laboratory Standards (NCCLS). Screening for vancomycin resistance was done by the vancomycin screen agar method recommended by NCCLS, which was confirmed by determination of minimum inhibitory concentration (MIC) using microbroth dilution and E-test methods. Vancomycin resistance phenotypes were determined by polymerase chain reaction. RESULTS: A total of 115 (26%) isolates had high level aminoglycoside resistance, 293 (66%) were resistant to ampicillin, 391 (88%) to ciprofloxacin and 377 (85%) to erythromycin. Vancomycin resistance was found in five (1%) isolates, of which four had van A phenotype and one had van B phenotype. INTERPRETATION & CONCLUSION: Emergence of vancomycin resistant enterococci is of concern due to the limited therapeutic options. Implementation of infection control measures can contain the spread of these resistant bacteria.

Base Sequence↗

PubMed1998

Insertion vectors for construction of recombinant conjugative transposons in Bacillus subtilis and Enterococcus faecalis.

The broad-host range of conjugal transfer and the chromosomal location make conjugative transposons (CT) attractive candidates as tools for genetic manipulation of a large variety of bacteria. In this paper we describe insertion vectors capable of integrating into Tn916, the prototype of CT in Gram-positive bacteria. The integration of vectors into a single chromosomal copy of Tn916 was studied both after natural transformation of Bacillus subtilis, and after electroporation in Enterococcus faecalis. Integration occurred either by double or by single crossover, and the integrated DNA segment was shown to be highly stable. All recombinant CT (rCT) were still able to excise from the chromosome to form circular intermediates, the first step of both transposition and conjugal transfer. All classes of rCT generated by insertion vector pSMB47 were capable of conjugal transfer, while using pVMB11 it was possible to generate non-conjugative rCT.

Bacillus subtilis↗

PubMed1990

Efficacy of teicoplanin in two dosage regimens for experimental endocarditis caused by a beta-lactamase-producing strain of Enterococcus faecalis with high-level resistance to gentamicin.

Optimal therapy for the treatment of infections caused by strains of enterococci demonstrating high-level resistance to gentamicin and other aminoglycosides has not been established. The present study examined the efficacy of teicoplanin, a glycopeptide antibiotic active against gram-positive bacterial infections in various animal models, in the treatment of experimental endocarditis due to a beta-lactamase-producing strain of Enterococcus faecalis with high-level resistance to gentamicin. Vancomycin was used as a comparative antibiotic. In the first set of experiments, both antimicrobial agents were administered by continuous intravenous infusion for 5 days at dosages which yielded comparable mean levels in serum (plus or minus the standard deviation) of 14.6 +/- 4.3 micrograms/ml for teicoplanin and 14.3 +/- 2.2 micrograms/ml for vancomycin. These regimens proved similarly effective in sterilizing cardiac vegetations (38 versus 50% of treated animals, respectively; P greater than 0.05). Mean (plus or minus the standard deviation) residual bacterial titers within vegetations were reduced to 3.2 +/- 1.2 log10 CFU/g and 3.4 +/- 1.7 log10 CFU/g, respectively. In separate experiments, the potential of teicoplanin to cure endocarditis was assessed, using two dosage regimens: (i) 30 mg/kg per day (mean level in serum, 13 micrograms/ml) for 10 days or (ii) 150 mg/kg per day (mean level in serum, 84 micrograms/ml) for 5 days. Surviving animals were sacrificed 10 days after the discontinuation of therapy. Both teicoplanin regimens were more effective than the comparative vancomycin (150 mg/kg per day) regimen: 92 versus 43% cured (P =0.025) in the standard-dose group, and 82 versus 37% cured (P = 0.015) in the high-dose group. Results in this rat model of enterococcal endocarditis show that teicoplanin may prove useful in the treatment of serious infections due to high level-gentamicin-resistant enterococci in humans.

Animals↗

PubMed2002

[Conjugative transfer of glycopeptide and macrolide resistant genes among Enterococci and from Enterococcus faecalis to Staphylococcus aureus].

The resistance determinants were transferred from clinical strains of enterococci to Staphylococcus aureus strains. As recipients methicillin-resistant and methicillin-susceptible strains were used and the filter-mating procedure was performed. The transconjugants resistant to erythromycin were obtained in the case of all recipients, in one case the vanA determinant conferring the resistance to vancomycin was transferred together with erythromycin resistance. However the resistance was very unstable and the level was not as high as in the case of Enterococcus faecalis donor strain. The vanA determinant was easily transferred between enterococcal strains by the conjugation and a transfer occurred of vanA alone or together with erythromycin resistance.

Anti-Bacterial Agents↗

PubMed2006

Killing of Enterococcus faecalis by MTAD and chlorhexidine digluconate with or without cetrimide in the presence or absence of dentine powder or BSA.

The antibacterial efficacy of irrigating solutions and local disinfectants used in endodontics appears poorer in vivo than in vitro. One explanation may be inactivation by compounds present in the root canal. MTAD (a mixture of tetracycline isomer, acid, and detergent) is a new root canal irrigation solution with antibacterial activity. The aim of this study was to investigate the antibacterial activity of MTAD and chlorhexidine towards two strains of Enterococcus faecalis and the inhibitory effects of dentine and bovine serum albumin on the antibacterial activity. Survival of bacteria exposed to the medicaments in the presence or absence of inhibitors was monitored in an in vitro model. Full concentration (100%) MTAD and 0.2% chlorhexidine rapidly killed both strains. Combining chlorhexidine with cetrimide further reduced the time required for killing. The presence of dentine or BSA caused a marked delay in killing by both medicaments. The two E. faecalis strains tested showed minor differences in their susceptibility to the disinfectants.

Animals↗

PubMed2000

Once-daily aminoglycoside in the treatment of Enterococcus faecalis endocarditis: case report and review.

Once-daily administration of aminoglycosides (ODA) is effective and safe for many indications. By optimizing pharmacodynamic principles, it enhances bactericidal activity and minimizes toxicity. Its use for the treatment of enterococcal infection is controversial, however, and results of in vitro studies and animal models of endocarditis are conflicting. To date, no case reports or clinical trials have examined its utility in human enterococcal endocarditis. A patient with right-sided endocarditis caused by Enterococcus faecalis was managed by once-daily gentamicin. Clinical and bacteriologic cures of this patient raise questions as to whether enterococcal endocarditis should be regarded as contraindication to ODA. The clinical utility of ODA in this disease deserves further investigation.

Adult↗

PubMed2005

Garlic natural health products exhibit variable constituent levels and antimicrobial activity against Neisseria gonorrhoeae, Staphylococcus aureus and Enterococcus faecalis.

The composition of 19 garlic natural health products (NHPs) and fresh garlic extracts were determined, as was their antibacterial activity. The 19 NHPs and 5 fresh garlic extract standards were analysed for their principal active constituents. They were also extracted for 5, 10 or 15 min in water to fresh garlic equivalents of 200 mg/mL. The extract's minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) against three indicator microorganisms (Neisseria gonorrhoeae, Staphylococcus aureus and Enterococcus faecalis) were determined by the broth microdilution method. While 47% of the aqueous garlic NHP extracts exhibited activity against N. gonorrhoeae, only 16% of the aqueous extracts inhibited S. aureus or E. faecalis at all three timepoints. Generally, products with high antimicrobial activity contained higher levels of garlic constituents with comparable activity to fresh garlic extracts, while products with marginal antibacterial activity often contained lower concentrations of constituents than their product labels indicated. Different extraction times affected antibacterial activity only against N. gonorrhoeae and tended to be correlated with levels of allicin. Thus, many extracts showed discrepancies in both composition, allicin:alliin ratio and antimicrobial activity, raising concerns as to standards of preparation and quality control for these products.

Anti-Bacterial Agents↗

PubMed2005

Structure of peptide sex pheromone receptor PrgX and PrgX/pheromone complexes and regulation of conjugation in Enterococcus faecalis.

Many bacterial activities, including expression of virulence factors, horizontal genetic transfer, and production of antibiotics, are controlled by intercellular signaling using small molecules. To date, understanding of the molecular mechanisms of peptide-mediated cell-cell signaling has been limited by a dearth of published information about the molecular structures of the signaling components. Here, we present the molecular structure of PrgX, a DNA- and peptide-binding protein that regulates expression of the conjugative transfer genes of the Enterococcus faecalis plasmid pCF10 in response to an intercellular peptide pheromone signal. Comparison of the structures of PrgX and the PrgX/pheromone complex suggests that pheromone binding destabilizes PrgX tetramers, opening a 70-bp pCF10 DNA loop required for conjugation repression.

Base Sequence↗

PubMed1998

Glycerol monolaurate inhibits induction of vancomycin resistance in Enterococcus faecalis.

Glycerol monolaurate (GML) is a surfactant that has been found to inhibit the post-exponential phase activation of virulence factor production and the induction of beta-lactamase in Staphylococcus aureus. It has been suggested that signal transduction is the most probable target for GML (S. J. Projan, S. Brown-Skrobot, P. M. Schlievert, F. Vandenesch, and R. P. Novick, J. Bacteriol. 176:4204-4209, 1994). We found that GML suppresses growth of vancomycin-resistant Enterococcus faecalis on plates with vancomycin and blocks the induction of vancomycin resistance, which involves a membrane-associated signal transduction mechanism, either at or before initiation of transcription. Given the surfactant nature of GML and the results of previous experiments, we suggest that GML blocks signal transduction. In contrast, GML has no effect on the induction of erythromycin-inducible macrolide resistance in S. aureus, which does not involve signal transduction.

Anti-Bacterial Agents↗

PubMed2000

Cell wall chemical composition of Enterococcus faecalis in the viable but nonculturable state.

The viable but nonculturable (VBNC) state is a survival mechanism adopted by many bacteria (including those of medical interest) when exposed to adverse environmental conditions. In this state bacteria lose the ability to grow in bacteriological media but maintain viability and pathogenicity and sometimes are able to revert to regular division upon restoration of normal growth conditions. The aim of this work was to analyze the biochemical composition of the cell wall of Enterococcus faecalis in the VBNC state in comparison with exponentially growing and stationary cells. VBNC enterococcal cells appeared as slightly elongated and were endowed with a wall more resistant to mechanical disruption than dividing cells. Analysis of the peptidoglycan chemical composition showed an increase in total cross-linking, which rose from 39% in growing cells to 48% in VBNC cells. This increase was detected in oligomers of a higher order than dimers, such as trimers (24% increase), tetramers (37% increase), pentamers (65% increase), and higher oligomers (95% increase). Changes were also observed in penicillin binding proteins (PBPs), the enzymes involved in the terminal stages of peptidoglycan assembly, with PBPs 5 and 1 being prevalent, and in autolytic enzymes, with a threefold increase in the activity of latent muramidase-1 in E. faecalis in the VBNC state. Accessory wall polymers such as teichoic acid and lipoteichoic acid proved unchanged and doubled in quantity, respectively, in VBNC cells in comparison to dividing cells. It is suggested that all these changes in the cell wall of VBNC enterococci are specific to this particular physiological state. This may provide indirect confirmation of the viability of these cells.

Bacterial Proteins↗

PubMed2005

X-ray crystal structures of HMG-CoA synthase from Enterococcus faecalis and a complex with its second substrate/inhibitor acetoacetyl-CoA.

Biosynthesis of the isoprenoid precursor, isopentenyl diphosphate, is a critical function in all independently living organisms. There are two major pathways for this synthesis, the non-mevalonate pathway found in most eubacteria and the mevalonate pathway found in animal cells and a number of pathogenic bacteria. An early step in this pathway is the condensation of acetyl-CoA and acetoacetyl-CoA into HMG-CoA, catalyzed by the enzyme HMG-CoA synthase. To explore the possibility of a small molecule inhibitor of the enzyme functioning as a non-cell wall antibiotic, the structure of HMG-CoA synthase from Enterococcus faecalis (MVAS) was determined by selenomethionine MAD phasing to 2.4 A and the enzyme complexed with its second substrate, acetoacetyl-CoA, to 1.9 A. These structures show that HMG-CoA synthase from Enterococcus is a member of the family of thiolase fold enzymes and, while similar to the recently published HMG-CoA synthase structures from Staphylococcus aureus, exhibit significant differences in the structure of the C-terminal domain. The acetoacetyl-CoA binary structure demonstrates reduced coenzyme A and acetoacetate covalently bound to the active site cysteine through a thioester bond. This is consistent with the kinetics of the reaction that have shown acetoacetyl-CoA to be a potent inhibitor of the overall reaction, and provides a starting point in the search for a small molecule inhibitor.

Acetoacetates↗

PubMed1989

In vitro postantibiotic effect of daptomycin (LY146032) against Enterococcus faecalis and methicillin-susceptible and methicillin-resistant Staphylococcus aureus strains.

The suppression of bacterial growth that persists after brief exposure to antimicrobial agents has been termed the postantibiotic effect (PAE). This pharmacodynamic interaction varies for each microorganism-antimicrobial agent combination. Daptomycin (LY146032) is a new lipopeptide antibiotic with activity against gram-positive organisms. We studied the in vitro bactericidal activities and PAEs of the following drugs: daptomycin compared with penicillin G and vancomycin, without and with gentamicin against Enterococcus faecalis strains; daptomycin compared with nafcillin and vancomycin against methicillin-susceptible Staphylococcus aureus strains; and daptomycin compared with vancomycin against methicillin-resistant S. aureus strains. Daptomycin, alone and when used in combination with gentamicin, exhibited greater bactericidal activity and in general produced a longer PAE than standard effective regimens against the organism strains studied.

Anti-Bacterial Agents↗

PubMed1997

The effect of Tn916 insertions on contour-clamped homogeneous electrophoresis patterns of Enterococcus faecalis.

Contour-clamped homogeneous gel electrophoresis has increasingly been used and has generally been considered the method of choice for the delineation of enterococcial strains. It has been suggested that the contour-clamped homogeneous electric field (CHEF) electrophoresis digestion patterns of genomic DNA indicate the relatedness of strains when SmaI patterns differ by six or fewer bands. To evaluate the potential reasons for the diversity of bands among clonally related isolates, we studied plasmid-free Enterococcus faecalis FA2-2 and derivatives with transposon Tn916 (encoding for tetracycline resistance) insertions on the chromosome. We obtained derivatives with seven different Tn916 insertion sites and up to two copies of Tn916 on the chromosome, resulting in differences of one to seven bands by CHEF electrophoresis; eight different patterns were observed. With Tn916 insertions, there was either (i) loss of a band(s) with the generation of a new band(s), (ii) the generation of a new band(s) only, or (iii) the loss of a band(s) with no new visible band(s). These results indicate that strains can have up to seven different SmaI bands by CHEF electrophoresis and still be closely related.

Bacterial Typing Techniques↗