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Sample records for enterococcus faecalis illustrated

  1. Genetic Diversity among Enterococcus faecalis

    PubMed Central

    McBride, Shonna M.; Fischetti, Vincent A.; LeBlanc, Donald J.; Moellering, Robert C.; Gilmore, Michael S.

    2007-01-01

    Enterococcus faecalis, a ubiquitous member of mammalian gastrointestinal flora, is a leading cause of nosocomial infections and a growing public health concern. The enterococci responsible for these infections are often resistant to multiple antibiotics and have become notorious for their ability to acquire and disseminate antibiotic resistances. In the current study, we examined genetic relationships among 106 strains of E. faecalis isolated over the past 100 years, including strains identified for their diversity and used historically for serotyping, strains that have been adapted for laboratory use, and isolates from previously described E. faecalis infection outbreaks. This collection also includes isolates first characterized as having novel plasmids, virulence traits, antibiotic resistances, and pathogenicity island (PAI) components. We evaluated variation in factors contributing to pathogenicity, including toxin production, antibiotic resistance, polymorphism in the capsule (cps) operon, pathogenicity island (PAI) gene content, and other accessory factors. This information was correlated with multi-locus sequence typing (MLST) data, which was used to define genetic lineages. Our findings show that virulence and antibiotic resistance traits can be found within many diverse lineages of E. faecalis. However, lineages have emerged that have caused infection outbreaks globally, in which several new antibiotic resistances have entered the species, and in which virulence traits have converged. Comparing genomic hybridization profiles, using a microarray, of strains identified by MLST as spanning the diversity of the species, allowed us to identify the core E. faecalis genome as consisting of an estimated 2057 unique genes. PMID:17611618

  2. Enterococcus faecalis grows on ascorbic acid.

    PubMed

    Mehmeti, Ibrahim; Solheim, Margrete; Nes, Ingolf F; Holo, Helge

    2013-08-01

    We show that Enterococcus faecalis can utilize ascorbate for fermentative growth. In chemically defined media, growth yield was limited by the supply of amino acids, and the cells showed a much higher demand for amino acids than when they were grown on glucose.

  3. Targeting Enterococcus faecalis biofilms with phage therapy.

    PubMed

    Khalifa, Leron; Brosh, Yair; Gelman, Daniel; Coppenhagen-Glazer, Shunit; Beyth, Shaul; Poradosu-Cohen, Ronit; Que, Yok-Ai; Beyth, Nurit; Hazan, Ronen

    2015-04-01

    Phage therapy has been proven to be more effective, in some cases, than conventional antibiotics, especially regarding multidrug-resistant biofilm infections. The objective here was to isolate an anti-Enterococcus faecalis bacteriophage and to evaluate its efficacy against planktonic and biofilm cultures. E. faecalis is an important pathogen found in many infections, including endocarditis and persistent infections associated with root canal treatment failure. The difficulty in E. faecalis treatment has been attributed to the lack of anti-infective strategies to eradicate its biofilm and to the frequent emergence of multidrug-resistant strains. To this end, an anti-E. faecalis and E. faecium phage, termed EFDG1, was isolated from sewage effluents. The phage was visualized by electron microscopy. EFDG1 coding sequences and phylogeny were determined by whole genome sequencing (GenBank accession number KP339049), revealing it belongs to the Spounavirinae subfamily of the Myoviridae phages, which includes promising candidates for therapy against Gram-positive pathogens. This analysis also showed that the EFDG1 genome does not contain apparent harmful genes. EFDG1 antibacterial efficacy was evaluated in vitro against planktonic and biofilm cultures, showing effective lytic activity against various E. faecalis and E. faecium isolates, regardless of their antibiotic resistance profile. In addition, EFDG1 efficiently prevented ex vivo E. faecalis root canal infection. These findings suggest that phage therapy using EFDG1 might be efficacious to prevent E. faecalis infection after root canal treatment.

  4. Targeting Enterococcus faecalis Biofilms with Phage Therapy

    PubMed Central

    Khalifa, Leron; Brosh, Yair; Gelman, Daniel; Coppenhagen-Glazer, Shunit; Beyth, Shaul; Poradosu-Cohen, Ronit; Que, Yok-Ai; Beyth, Nurit

    2015-01-01

    Phage therapy has been proven to be more effective, in some cases, than conventional antibiotics, especially regarding multidrug-resistant biofilm infections. The objective here was to isolate an anti-Enterococcus faecalis bacteriophage and to evaluate its efficacy against planktonic and biofilm cultures. E. faecalis is an important pathogen found in many infections, including endocarditis and persistent infections associated with root canal treatment failure. The difficulty in E. faecalis treatment has been attributed to the lack of anti-infective strategies to eradicate its biofilm and to the frequent emergence of multidrug-resistant strains. To this end, an anti-E. faecalis and E. faecium phage, termed EFDG1, was isolated from sewage effluents. The phage was visualized by electron microscopy. EFDG1 coding sequences and phylogeny were determined by whole genome sequencing (GenBank accession number KP339049), revealing it belongs to the Spounavirinae subfamily of the Myoviridae phages, which includes promising candidates for therapy against Gram-positive pathogens. This analysis also showed that the EFDG1 genome does not contain apparent harmful genes. EFDG1 antibacterial efficacy was evaluated in vitro against planktonic and biofilm cultures, showing effective lytic activity against various E. faecalis and E. faecium isolates, regardless of their antibiotic resistance profile. In addition, EFDG1 efficiently prevented ex vivo E. faecalis root canal infection. These findings suggest that phage therapy using EFDG1 might be efficacious to prevent E. faecalis infection after root canal treatment. PMID:25662974

  5. [Investigation of Enterococcus faecalis antimicrobial resistance].

    PubMed

    Casal, M M; Cause, M; Solís, F; Rodríz, F; Casal, M

    2009-09-01

    We performed an antibiotic resistance study on Enterococcus faecalis isolated from intrahospitalary and extrahospitalary samples between january 2004 and january 2008. Three different samples were studied; urine, blood and wound swabs, considering a strain per patient. We included in the study a global amount of 3,641 Enterococcus faecalis isolations from clinical samples received at Hospital Universitario Reina Sofía microbiology service in Córdoba (Spain). We employed semiautomatic system WIDER I (Soria Melguizo) for identification and sensibility testing. We considered sensibility and resistance criteria recommended by MENSURA group. We found a sensitivity rate of 98.04% to betalactamics.The highest resistance rates were obtained with aminoglycosides, between 33.82% and 48.01%. Linezolid and Vancomycin sensitivity was 100%. It seems that vancomycin resistance is not a worrying issue today, but it should be controlled.

  6. Transcriptional response of Enterococcus faecalis to sunlight.

    PubMed

    Sassoubre, Lauren M; Ramsey, Matthew M; Gilmore, Michael S; Boehm, Alexandria B

    2014-01-05

    Microarrays were used to investigate the transcriptional response of Enterococcus faecalis to photostress. E. faecalis are Gram-positive bacteria used as indicators of water quality and have been shown to vary diurnally in response to sunlight. E. faecalis in filtered seawater microcosms were exposed to artificial sunlight for 12h and then placed in the dark for 12h. Transcript abundance was measured at 0, 2, 6, 12, and 24h in the sunlit microcosm and a dark control using microarrays. Culturable E. faecalis concentrations decreased 6-7 orders of magnitude within the first 6h of light exposure. After 12h in the dark, no evidence of dark-repair was observed. Expression data collected after 12h of sunlight exposure revealed a difference in transcript abundance in the light relative to dark microcosms for 35 unique ORFs, 33 ORFs showed increased transcript abundance and 2 ORFs showed reduced transcript abundance. A majority (51%) of the ORFs with increased transcript abundance in the sunlit relative to dark microcosms encoded hypothetical proteins; others were associated with protein synthesis, oxidative stress and DNA repair. Results suggest that E. faecalis exposed to sunlight actively transcribe RNA in response to photostress.

  7. Pheromone-inducible conjugation in Enterococcus faecalis

    PubMed Central

    Kozlowicz, Briana K.; Dworkin, Martin; Dunny, Gary M.

    2009-01-01

    Pheromone-inducible transfer of the plasmid pCF10 in Enterococcus faecalis is regulated using a complicated network of proteins and RNAs. The plasmid itself has been assembled from parts garnered from a variety of sources, and many aspects of the system resemble a biological kluge. Recently several new functions of various pCF10 gene products that participate in regulation of plasmid transfer have been identified. The results indicate that selective pressures controlling the evolution of the plasmid have produced a highly complex regulatory network with multiple biological functions that may serve well as a model for the evolution of biological complexity. PMID:16503196

  8. Characterization of monolaurin resistance in Enterococcus faecalis.

    PubMed

    Dufour, Muriel; Manson, Janet M; Bremer, Philip J; Dufour, Jean-Pierre; Cook, Gregory M; Simmonds, Robin S

    2007-09-01

    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 microg/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.

  9. Enterococcus faecalis antigens in human infections.

    PubMed

    Xu, Y; Jiang, L; Murray, B E; Weinstock, G M

    1997-10-01

    Genomic libraries of two Enterococcus faecalis strains, OG1RF and TX52 (an isolate from an endocarditis patient), were constructed in cosmid vectors pBeloBAC11 and pLAFRx, and screened with a serum from a rabbit immunized with surface proteins of an E. faecalis endocarditis isolate and sera from four patients with enterococcal endocarditis. Seventy-five cosmid clones reacted with at least two of the sera. Thirty-eight of the 75 immunopositive clones were considered to contain distinct inserts based on their DNA restriction patterns and were chosen for further subcloning into a pBluescript vector. Each sublibrary was screened with one of the five sera, and the DNA sequence of the immunopositive subclones was determined. Analysis of these sequences revealed similarities to a range of proteins, including bacterial virulence factors, transporters, two-component regulators, metabolic enzymes, and membrane or cell surface proteins. Fourteen subclones did not show significant similarity to any sequence in the databases and may contain novel genes. Thirteen of the immunopositive cosmid clones did not yield immunopositive subclones, and one such cosmid clone produced a nonprotein antigen in Escherichia coli.

  10. Genome Sequence of Enterococcus faecalis Strain CG_E

    PubMed Central

    Gabris, Christina; Daniel, Rolf

    2017-01-01

    ABSTRACT Enterococcus faecalis CG_E is a Gram-positive, lactic acid-producing coccus. The draft genome of E. faecalis strain CG_E comprises 2,969,881 bp and exhibits a G+C content of 37.34%. The genome encodes 2,848 predicted protein-encoding and 97 RNA genes. PMID:28082508

  11. Genome Sequence of Enterococcus faecalis Strain CG_E.

    PubMed

    Gabris, Christina; Poehlein, Anja; Bengelsdorf, Frank R; Daniel, Rolf; Dürre, Peter

    2017-01-12

    Enterococcus faecalis CG_E is a Gram-positive, lactic acid-producing coccus. The draft genome of E. faecalis strain CG_E comprises 2,969,881 bp and exhibits a G+C content of 37.34%. The genome encodes 2,848 predicted protein-encoding and 97 RNA genes.

  12. Sensitivity to detergents and plasmid curing in Enterococcus faecalis.

    PubMed

    Keyhani, Jacqueline; Keyhani, Ezzatollah; Attar, Farnoosh; Haddadi, Azam

    2006-03-01

    This research reports the sensitivity of a clinical isolate of Enterococcus faecalis to sodium N-lauroylsarcosinate (sarkosyl) and sodium dodecyl sulfate (SDS), as well as the efficiency of these detergents in curing the strain. Compared to Escherichia coli, Enterococcus faecalis was very sensitive to both detergents, with minimum inhibitory concentrations (MIC) for the latter being 100 times lower than for Escherichia coli. The clinical isolate of Enterococcus faecalis used in this study exhibited plasmid-borne resistance to kanamycin (MIC 2 mg/ml) and tetracycline (MIC 50 mug/ml); 3% curing was observed after growth in the presence of sarkosyl but no curing was observed after growth in the presence of either SDS or acridine orange. In contrast, 35% curing of plasmid-bearing Escherichia coli was observed after growth in the presence of either SDS or acridine orange, but none was observed after growth in the presence of sarkosyl.

  13. Antimicrobial Susceptibility Patterns of Enterococcus faecalis and Enterococcus faecium Isolated from Poultry Flocks in Germany.

    PubMed

    Maasjost, J; Mühldorfer, K; Cortez de Jäckel S; Hafez, H M

    2015-03-01

    Between 2010 and 2011, 145 Enterococcus isolates (Enterococcus faecalis, n = 127; Enterococcus faecium, n = 18) were collected during routine bacteriologic diagnostics from broilers, layers, and fattening turkeys in Germany showing various clinical signs. The susceptibility to 24 antimicrobial agents was investigated by broth microdilution test to determine minimum inhibitory concentrations (MICs). All E. faecalis isolates (n = 127) were susceptible to the beta-lactam antibiotics ampicillin, amoxicillin-clavulanic acid, and penicillin. Corresponding MIC with 50% inhibition (MIC50) and MIC with 90% inhibition (MIC90) values of these antimicrobial agents were at the lower end of the test range (≤ 4 μg/ml). In addition, no vancomycin-resistant enterococci (VRE) were found. High resistance rates were identified in both Enterococcus species for lincomycin (72%-99%) and tetracycline (67%-82%). Half or more than half of Enterococcus isolates were resistant to gentamicin (54%-72%) and the macrolide antibiotics erythromycin (44%-61%) and tylosin-tartate (44%-56%). Enterococcus faecalis isolated from fattening turkeys showed the highest prevalence of antimicrobial resistance compared to other poultry production systems. Eighty-nine out of 145 Enterococcus isolates were resistant to three or more antimicrobial classes. Again, turkeys stood out with 42 (8 1%) multiresistant isolates. The most-frequent resistance patterns of E. faecalis were gentamicin, lincomycin, and tetracycline in all poultry production systems.

  14. An antimicrobial peptidoglycan hydrolase for treating Enterococcus faecalis

    USDA-ARS?s Scientific Manuscript database

    Enterococcus faecalis is an intestinal bacteria species that can become an opportunistic pathogen in humans and farm animals with antibiotic resistant strains becoming increasingly common. In farm animals, strong antimicrobials, such as Vancomycin, should not be used due to the risk of propagation ...

  15. Enterococcus faecalis promotes osteoclastogenesis and semaphorin 4D expression.

    PubMed

    Wang, Shuai; Deng, Zuhui; Seneviratne, Chaminda J; Cheung, Gary S P; Jin, Lijian; Zhao, Baohong; Zhang, Chengfei

    2015-10-01

    Enterococcus faecalis is considered a major bacterial pathogen implicated in endodontic infections and contributes considerably to periapical periodontitis. This study aimed to investigate the potential mechanisms by which E. faecalis accounts for the bone destruction in periapical periodontitis in vitro. Osteoclast precursor RAW264.7 cells were treated with E. faecalis ATCC 29212 and a wild strain of E. faecalis derived clinically from an infected root canal. The results showed that, to some extent, E. faecalis induced the RAW264.7 cells to form tartrate-resistant acid phosphatase (TRAP)-positive multinucleated osteoclast-like cells. This pathogen markedly stimulated RAW264.7 cells to express semaphorin 4D (Sema4D), which inhibits bone formation. Once RAW264.7 cells were primed by low-dose receptor activator of nuclear factor-kappa B ligand (RANKL), E. faecalis could significantly increase the production of TRAP-positive multinucleated cells and up-regulate the expression of osteoclast-specific markers, including NFATc1, TRAP and cathepsin K. Both p38 and ERK1/2 MAPK signaling pathways were activated by E. faecalis in RANKL-primed RAW264.7 cells, and meanwhile the expression of Sema4D was highly increased. In conclusion, E. faecalis may greatly contribute to the bone resorption in periapical periodontitis by promoting RANKL-dependent osteoclastogenesis and expression of Sema4D through activation of p38 and ERK1/2 MAPK signaling pathways.

  16. Transcriptome analysis of Enterococcus faecalis in response to alkaline stress

    PubMed Central

    Ran, Shujun; Liu, Bin; Jiang, Wei; Sun, Zhe; Liang, Jingping

    2015-01-01

    Enterococcus faecalis is the most commonly isolated species from endodontic failure root canals; its persistence in treated root canals has been attributed to its ability to resist high pH stress. The goal of this study was to characterize the E. faecalis transcriptome and to identify candidate genes for response and resistance to alkaline stress using Illumina HiSeq 2000 sequencing. We found that E. faecalis could survive and form biofilms in a pH 10 environment and that alkaline stress had a great impact on the transcription of many genes in the E. faecalis genome. The transcriptome sequencing results revealed that 613 genes were differentially expressed (DEGs) for E. faecalis grown in pH 10 medium; 211 genes were found to be differentially up-regulated and 402 genes differentially down-regulated. Many of the down-regulated genes found are involved in cell energy production and metabolism and carbohydrate and amino acid metabolism, and the up-regulated genes are mostly related to nucleotide transport and metabolism. The results presented here reveal that cultivation of E. faecalis in alkaline stress has a profound impact on its transcriptome. The observed regulation of genes and pathways revealed that E. faecalis reduced its carbohydrate and amino acid metabolism and increased nucleotide synthesis to adapt and grow in alkaline stress. A number of the regulated genes may be useful candidates for the development of new therapeutic approaches for the treatment of E. faecalis infections. PMID:26300863

  17. Probiotic potential of Enterococcus faecalis strains isolated from meconium

    PubMed Central

    Al Atya, Ahmed K.; Drider-Hadiouche, Karima; Ravallec, Rozenn; Silvain, Amadine; Vachee, Anne; Drider, Djamel

    2015-01-01

    107 bacterial isolates with Gram positive staining and negative catalase activity, presumably assumed as lactic acid bacteria, were isolated from samples of meconium of 6 donors at Roubaix hospital, in the north of France. All these bacterial isolates were identified by MALDI-TOF mass spectrometry as Enterococcus faecalis. However, only six isolates among which E. faecalis 14, E. faecalis 28, E. faecalis 90, E. faecalis 97, and E. faecalis 101 (obtained from donor 3), and E. faecalis 93 (obtained from donor 5) were active against some Gram-negative bacteria and Gram-positive bacteria , through production of lactic acid, and bacteriocin like inhibitory substances. The identification of these isolates was confirmed by 16rDNA sequencing and their genetic relatedness was established by REP-PCR and pulsed field gel electrophoresis methods. Importantly, the aforementioned antagonistic isolates were sensitive to various classes of antibiotics tested, exhibited high scores of coaggregation and hydrophobicity, and were not hemolytic. Taken together, these properties render these strains as potential candidates for probiotic applications. PMID:25883590

  18. Efficacy of Ceftobiprole Medocaril against Enterococcus faecalis in a Murine Urinary Tract Infection Model

    PubMed Central

    Murray, Barbara E.

    2012-01-01

    We evaluated ceftobiprole against the well-characterized Enterococcus faecalis strain OG1RF (with and without the β-lactamase [Bla] plasmid pBEM10) in a murine urinary tract infection (UTI) model. Ceftobiprole was equally effective for Bla+ and Bla− OG1 strains, while ampicillin was moderately to markedly (depending on the inoculum) less effective against Bla+ than Bla− OG1 strains. These data illustrate an in vivo effect on ampicillin of Bla production by E. faecalis and the stability and efficacy of ceftobiprole in experimental UTI. PMID:22450988

  19. Mature biofilms of Enterococcus faecalis and Enterococcus faecium are highly resistant to antibiotics.

    PubMed

    Holmberg, Anna; Rasmussen, Magnus

    2016-01-01

    Enterococcus faecalis and Enterococcus faecium are important nosocomial pathogens that form biofilms on implanted materials. We compare the antibiotic sensitivity of bacteria in new (established during 24 hours) and mature (established during 120 hours) enterococcal biofilms. Mature biofilms contained more bacteria and were much more tolerant to antibiotics, including rifampicin-containing combinations, as judged by determination of minimal biofilm eradication concentrations and by time-kill experiments of bacteria in biofilms formed on beads of bone cement.

  20. Association of Enterococcus faecalis with different forms of periradicular diseases.

    PubMed

    Rôças, Isabela N; Siqueira, José F; Santos, Kátia R N

    2004-05-01

    Data from culture studies have revealed that Enterococcus faecalis is occasionally isolated from primary endodontic infections but frequently recovered from treatment failures. This molecular study was undertaken to investigate the prevalence of E. faecalis in endodontic infections and to determine whether this species is associated with particular forms of periradicular diseases. Samples were taken from cases of untreated teeth with asymptomatic chronic periradicular lesions, acute apical periodontitis, or acute periradicular abscesses, and from root-filled teeth associated with asymptomatic chronic periradicular lesions. DNA was extracted from the samples, and a 16S rDNA-based nested polymerase chain reaction assay was used to identify E. faecalis. This species occurred in seven of 21 root canals associated with asymptomatic chronic periradicular lesions, in one of 10 root canals associated with acute apical periodontitis, and in one of 19 pus samples aspirated from acute periradicular abscesses. Statistical analysis showed that E. faecalis was significantly more associated with asymptomatic cases than with symptomatic ones. E. faecalis was detected in 20 of 30 cases of persistent endodontic infections associated with root-filled teeth. When comparing the frequencies of this species in 30 cases of persistent infections with 50 cases of primary infections, statistical analysis demonstrated that E. faecalis was strongly associated with persistent infections. The average odds of detecting E. faecalis in cases of persistent infections associated with treatment failure were 9.1. The results of this study indicated that E. faecalis is significantly more associated with asymptomatic cases of primary endodontic infections than with symptomatic ones. Furthermore, E. faecalis was much more likely to be found in cases of failed endodontic therapy than in primary infections.

  1. Endocarditis and biofilm-associated pili of Enterococcus faecalis

    PubMed Central

    Nallapareddy, Sreedhar R.; Singh, Kavindra V.; Sillanpää, Jouko; Garsin, Danielle A.; Höök, Magnus; Erlandsen, Stanley L.; Murray, Barbara E.

    2006-01-01

    Increasing multidrug resistance in Enterococcus faecalis, a nosocomial opportunist and common cause of bacterial endocarditis, emphasizes the need for alternative therapeutic approaches such as immunotherapy or immunoprophylaxis. In an earlier study, we demonstrated the presence of antibodies in E. faecalis endocarditis patient sera to recombinant forms of 9 E. faecalis cell wall–anchored proteins; of these, we have now characterized an in vivo–expressed locus of 3 genes and an associated sortase gene (encoding sortase C; SrtC). Here, using mutation analyses and complementation, we demonstrated that both the ebp (encoding endocarditis and biofilm-associated pili) operon and srtC are important for biofilm production of E. faecalis strain OG1RF. In addition, immunogold electron microscopy using antisera against EbpA–EbpC proteins as well as patient serum demonstrated that E. faecalis produces pleomorphic surface pili. Assembly of pili and their cell wall attachment appeared to occur via a mechanism of cross-linking of the Ebp proteins by the designated SrtC. Importantly, a nonpiliated, allelic replacement mutant was significantly attenuated in an endocarditis model. These biologically important surface pili, which are antigenic in humans during endocarditis and encoded by a ubiquitous E. faecalis operon, may be a useful immunotarget for studies aimed at prevention and/or treatment of this pathogen. PMID:17016560

  2. In vitro susceptibility studies of vancomycin-resistant Enterococcus faecalis.

    PubMed Central

    Sahm, D F; Kissinger, J; Gilmore, M S; Murray, P R; Mulder, R; Solliday, J; Clarke, B

    1989-01-01

    Vancomycin resistance exhibited by Enterococcus faecalis isolates V583, V586, and V587 is described. The vancomycin MICs ranged from 32 to 64 micrograms/ml. Although resistant to vancomycin, the isolates were susceptible to teicoplanin (MIC, less than or equal to 0.5 micrograms/ml). Such a glycopeptide susceptibility profile has not been previously described for E. faecalis. Time kill studies showed that vancomycin resistance adversely affected the synergistic activity that vancomycin and aminoglycoside combinations usually demonstrate against enterococci. However, the ability to detect vancomycin resistance varied with the susceptibility testing method used. Whereas broth microdilution, broth macrodilution, and agar dilution methods detected resistance, disk-agar diffusion and the AutoMicrobic system Gram-Positive GPS-A susceptibility card (Vitek Systems Inc., Hazelwood, Mo.) did not. To detect vancomycin resistance reliably and establish the incidence of such E. faecalis isolates, adjustments in some susceptibility testing methods may be necessary. PMID:2554802

  3. Presence of virulence factors in Enterococcus faecalis and Enterococcus faecium susceptible and resistant to vancomycin

    PubMed Central

    Comerlato, Carolina Baldisserotto; de Resende, Mariah Costa Carvalho; Caierão, Juliana; d'Azevedo, Pedro Alves

    2013-01-01

    Despite the increasing importance of Enterococcus as opportunistic pathogens, their virulence factors are still poorly understood. This study determines the frequency of virulence factors in clinical and commensal Enterococcus isolates from inpatients in Porto Alegre, Brazil. Fifty Enterococcus isolates were analysed and the presence of the gelE, asa1 and esp genes was determined. Gelatinase activity and biofilm formation were also tested. The clonal relationships among the isolates were evaluated using pulsed-field gel electrophoresis. The asa1, gelE and esp genes were identified in 38%, 60% and 76% of all isolates, respectively. The first two genes were more prevalent in Enterococcus faecalis than in Enterococcus faecium, as was biofilm formation, which was associated with gelE and asa1 genes, but not with the esp gene. The presence of gelE and the activity of gelatinase were not fully concordant. No relationship was observed among any virulence factors and specific subclones of E. faecalis or E. faecium resistant to vancomycin. In conclusion, E. faecalis and E. faecium isolates showed significantly different patterns of virulence determinants. Neither the source of isolation nor the clonal relationship or vancomycin resistance influenced their distribution. PMID:23903974

  4. Enterococcus faecalis as multidrug resistance strains in clinical isolates in Imam Reza Hospital in Kermanshah, Iran.

    PubMed

    Mohammadi, F; Ghafourian, S; Mohebi, R; Taherikalani, M; Pakzad, I; Valadbeigi, H; Hatami, V; Sadeghifard, N

    2015-01-01

    The current study aimed to investigate the prevalence of vancomycin-resistant Enterococcus in E. faecalis and E. faecium and antimicrobial susceptibility patterns, then dominant genes responsible for vancomycin resistance were determined. For this propose, 180 clinical isolates of Enterococcus were subjected for identification and antibiotic susceptibility assay. Then, the gene responsible vancomycin resistant strains were determined. The results demonstrated the E. faecalis as a dominant Enterococcus. Resistance to erythromycin was dominant and multidrug resistance strains observed in E. faecalis. vanA was responsible for vancomycin resistance. In conclusion, a high rate of resistance to antibiotics in Enterococcus is clearly problematic, and a novel strategy is needed to decrease resistance in Enterococcus.

  5. Esp-independent biofilm formation by Enterococcus faecalis.

    PubMed

    Kristich, Christopher J; Li, Yung-Hua; Cvitkovitch, Dennis G; Dunny, Gary M

    2004-01-01

    Enterococcus faecalis is a gram-positive opportunistic pathogen known to form biofilms in vitro. In addition, this organism is often isolated from biofilms on the surfaces of various indwelling medical devices. However, the molecular mechanisms regulating biofilm formation in these clinical isolates are largely unknown. Recent work has suggested that a specific cell surface protein (Esp) of E. faecalis is critical for biofilm formation by this organism. However, in the same study, esp-deficient strains of E. faecalis were found to be capable of biofilm formation. To test the hypothesis that Esp is dispensable for biofilm formation by E. faecalis, we used microtiter plate assays and a chemostat-based biofilm fermentor assay to examine biofilm formation by genetically well-defined, non-Esp-expressing strains. Our results demonstrate that in vitro biofilm formation occurs, not only in the absence of esp, but also in the absence of the entire pathogenicity island that harbors the esp coding sequence. Using scanning electron microscopy to evaluate biofilms of E. faecalis OG1RF grown in the fermentor system, biofilm development was observed to progress through multiple stages, including attachment of individual cells to the substratum, microcolony formation, and maturation into complex multilayered structures apparently containing water channels. Microtiter plate biofilm analyses indicated that biofilm formation or maintenance was modulated by environmental conditions. Furthermore, our results demonstrate that expression of a secreted metalloprotease, GelE, enhances biofilm formation by E. faecalis. In summary, E. faecalis forms complex biofilms by a process that is sensitive to environmental conditions and does not require the Esp surface protein.

  6. Effect of a genetically engineered bacteriophage on Enterococcus faecalis biofilms.

    PubMed

    Tinoco, Justine Monnerat; Buttaro, Bettina; Zhang, Hongming; Liss, Nadia; Sassone, Luciana; Stevens, Roy

    2016-11-01

    Enterococcus faecalis is a Gram-positive, facultative anaerobic bacterium that is associated with failed endodontic cases and nosocomial infections. E. faecalis can form biofilms, penetrate dentinal tubules and survive in root canals with scarce nutritional supplies. These properties can make E. faecalis resistant to conventional endodontic disinfection therapy. Furthermore, treatment may be complicated by the fact that many E. faecalis strains are resistant to antibiotics. A potential alternative to antibiotic therapy is phage therapy. ϕEf11 is a temperate phage that infects strains of E. faecalis. It was previously sequenced and genetically engineered to modify its properties in order to render it useful as a therapeutic agent in phage therapy. In the current study, we have further genetically modified the phage to create phage ϕEf11/ϕFL1C(Δ36)(PnisA). The aim of this study was to evaluate the efficacy of bacteriophage ϕEf11/ϕFL1C(Δ36)(PnisA), to disrupt biofilms of two Enterococcus faecalis strains: JH2-2 (vancomycin-sensitive) and V583 (vancomycin-resistant). 24h static biofilms of E. faecalis strains JH2-2(pMSP3535 nisR/K) and V583 (pMSP3535nisR/K), formed on cover slips, were inoculated with bacteriophage ϕEf11/ϕFL1C(Δ36)(PnisA). After 24 and 48h incubation, the bacterial biomass was imaged by confocal microscopy and viable cells were quantified by colony forming unit measurement. The results showed a 10-100-fold decrease in viable cells (CFU/biofilm) after phage treatment, which was consistent with comparisons of treated and untreated biofilm images visualized as max projections of the Z-series. The biomass of both vancomycin-sensitive and vancomycin-resistant E. faecalis biofilms is markedly reduced following infection by bacteriophage ϕEf11/ϕFL1C(Δ36)(PnisA). Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Antibiotic Resistance in Enterococcus faecalis Isolated from Hospitalized Patients

    PubMed Central

    Balaei Gajan, Esrafil; Shirmohammadi, Adileh; Aghazadeh, Mohammad; Alizadeh, Mohammad; Sighari Deljavan, Alireza; Ahmadpour, Farzin

    2013-01-01

    Background and aims Enterococci are Gram-positive cocci that often occur in pairs (diplococci) or short chains. Be-side developing high level of antibiotic resistance, these bacteria can cause wide range of disease in human, thus to help provide an effective treatment for infections caused by this genus, this study was conceived to provide information on Enterococcus faecalis Antibiotic resistance to widely used antibiotics in hospitalized patients. Materials and methods Disk diffusion agar and Broth dilution methods were used to perform Antibiogram test on isolated Enterococcus faecalis. Culture medium used for Disk diffusion agar test was Muller Hinton agar, and for Broth dilution methods, Muller Hinton broth culture medium was utilized. In disk diffusion agar method, different commercial antibiotics disks produced by Pharmaceutical companies were used. Microsoft Excel software was used to perform statistical analysis. Results Based on antibiograms of 105 cases, a high resistance to Synercid, Nalidixic acid, Oxacillin and Teofilin was de-tected whereas the lowest resistance observed in Nitrofurantoin, Vancomycin, Linezolid and Teicoplanin antibiotics. Conclusion According to the results, Teicoplanin, Vancomycin, Linezolid and Nitrofurantoin are recommended against E. faecalis species. PMID:23875089

  8. Molecular characterization of Rifr mutations in Enterococcus faecalis and Enterococcus faecium.

    PubMed

    Du, Xiaoxing; Hua, Xiaoting; Qu, Tingting; Jiang, Yan; Zhou, Zhihui; Yu, Yunsong

    2014-08-01

    Mutation rate is an important factor affecting the appearance and spread of acquired antibiotic resistance. The frequencies and types of enterococci mutations were determined in this study. The MICs of rifampicin in enterococci and their rifampicin-resistant mutants were determined by the Clinical and Laboratory Standards Institute (CLSI) agar dilution method. The Enterococcus faecalis isolates A15 and 18165 showed no significant differences in mutation frequencies or mutation rates. In Enterococcus faecium, the mutation frequency and mutation rate were both 6·4-fold lower than in E. faecalis. The spectrum of mutations characterized in E. faecium B42 differed significantly from that of E. faecalis. The types and rate of mutations indicated that E. faecalis had a higher potential to develop linezolid resistance. Rifampicin resistance was associated with mutations in the rpoB gene. Rifampicin MICs for the E. faecalis mutant were 2048 mg/l, but rifampicin MICs for E. faecium mutants ranged from 64 to 1024 mg/l.

  9. Enterococcus faecalis Constitutes an Unusual Bacterial Model in Lysozyme Resistance▿

    PubMed Central

    Hébert, Laurent; Courtin, Pascal; Torelli, Riccardo; Sanguinetti, Maurizio; Chapot-Chartier, Marie-Pierre; Auffray, Yanick; Benachour, Abdellah

    2007-01-01

    Lysozyme is an important and widespread compound of the host constitutive defense system, and it is assumed that Enterococcus faecalis is one of the few bacteria that are almost completely lysozyme resistant. On the basis of the sequence analysis of the whole genome of E. faecalis V583 strain, we identified two genes that are potentially involved in lysozyme resistance, EF_0783 and EF_1843. Protein products of these two genes share significant homology with Staphylococcus aureus peptidoglycan O-acetyltransferase (OatA) and Streptococcus pneumoniae N-acetylglucosamine deacetylase (PgdA), respectively. In order to determine whether EF_0783 and EF_1843 are involved in lysozyme resistance, we constructed their corresponding mutants and a double mutant. The ΔEF_0783 mutant and ΔEF_0783 ΔEF_1843 double mutant were shown to be more sensitive to lysozyme than the parental E. faecalis JH2-2 strain and ΔEF_1843 mutant were. However, compared to other bacteria, such as Listeria monocytogenes or S. pneumoniae, the tolerance of ΔEF_0783 and ΔEF_0783 ΔEF_1843 mutants towards lysozyme remains very high. Peptidoglycan structure analysis showed that EF_0783 modifies the peptidoglycan by O acetylation of N-acetyl muramic acid, while the EF_1843 deletion has no obvious effect on peptidoglycan structure under the same conditions. Moreover, the EF_0783 and EF_1843 deletions seem to significantly affect the ability of E. faecalis to survive within murine macrophages. In all, while EF_0783 is currently involved in the lysozyme resistance of E. faecalis, peptidoglycan O acetylation and de-N-acetylation are not the main mechanisms conferring high levels of lysozyme resistance to E. faecalis. PMID:17785473

  10. Phage therapy against Enterococcus faecalis in dental root canals

    PubMed Central

    Khalifa, Leron; Shlezinger, Mor; Beyth, Shaul; Houri-Haddad, Yael; Coppenhagen-Glazer, Shunit; Beyth, Nurit; Hazan, Ronen

    2016-01-01

    Antibiotic resistance is an ever-growing problem faced by all major sectors of health care, including dentistry. Recurrent infections related to multidrug-resistant bacteria such as methicillin-resistant Staphylococcus aureus, carbapenem-resistant Enterobacteriaceae, and vancomycin-resistant enterococci (VRE) in hospitals are untreatable and question the effectiveness of notable drugs. Two major reasons for these recurrent infections are acquired antibiotic resistance genes and biofilm formation. None of the traditionally known effective techniques have been able to efficiently resolve these issues. Hence, development of a highly effective antibacterial practice has become inevitable. One example of a hard-to-eradicate pathogen in dentistry is Enterococcus faecalis, which is one of the most common threats observed in recurrent root canal treatment failures, of which the most problematic to treat are its biofilm-forming VRE strains. An effective response against such infections could be the use of bacteriophages (phages). Phage therapy was found to be highly effective against biofilm and multidrug-resistant bacteria and has other advantages like ease of isolation and possibilities for genetic manipulations. The potential of phage therapy in dentistry, in particular against E. faecalis biofilms in root canals, is almost unexplored. Here we review the efforts to develop phage therapy against biofilms. We also focus on the phages isolated against E. faecalis and discuss the possibility of using phages against E. faecalis biofilm in root canals. PMID:27640530

  11. Susceptibilities of Enterococcus faecalis biofilms to some antimicrobial medications.

    PubMed

    Lima, K C; Fava, L R; Siqueira, J F

    2001-10-01

    Enterococcus faecalis has been suggested to be an important etiological agent in endodontic failures. The purpose of this study was to evaluate the effectiveness of chlorhexidine- or antibiotics-based medications in eliminating E. faecalis biofilms. One-day and three-day biofilms of E. faecalis were induced on cellulose nitrate membrane filters. Each biofilm-containing membrane was thoroughly covered with 1 ml of the test medications and incubated for 1 day at 37 degrees C. Treated biofilms were then aseptically transferred to vials containing a neutralizing agent in saline solution and vortexed. Suspensions were 10-fold diluted, seeded onto Mitis salivarius agar plates, and the colony-forming units counted after 48 h of incubation. There were significant differences between the formulations tested. The association of clindamycin with metronidazole significantly reduced the number of cells in 1-day biofilms. However of all medications tested, only 2% chlorhexidine-containing medications were able to thoroughly eliminate most of both 1-day and 3-day E. faecalis biofilms.

  12. Phage therapy against Enterococcus faecalis in dental root canals.

    PubMed

    Khalifa, Leron; Shlezinger, Mor; Beyth, Shaul; Houri-Haddad, Yael; Coppenhagen-Glazer, Shunit; Beyth, Nurit; Hazan, Ronen

    2016-01-01

    Antibiotic resistance is an ever-growing problem faced by all major sectors of health care, including dentistry. Recurrent infections related to multidrug-resistant bacteria such as methicillin-resistant Staphylococcus aureus, carbapenem-resistant Enterobacteriaceae, and vancomycin-resistant enterococci (VRE) in hospitals are untreatable and question the effectiveness of notable drugs. Two major reasons for these recurrent infections are acquired antibiotic resistance genes and biofilm formation. None of the traditionally known effective techniques have been able to efficiently resolve these issues. Hence, development of a highly effective antibacterial practice has become inevitable. One example of a hard-to-eradicate pathogen in dentistry is Enterococcus faecalis, which is one of the most common threats observed in recurrent root canal treatment failures, of which the most problematic to treat are its biofilm-forming VRE strains. An effective response against such infections could be the use of bacteriophages (phages). Phage therapy was found to be highly effective against biofilm and multidrug-resistant bacteria and has other advantages like ease of isolation and possibilities for genetic manipulations. The potential of phage therapy in dentistry, in particular against E. faecalis biofilms in root canals, is almost unexplored. Here we review the efforts to develop phage therapy against biofilms. We also focus on the phages isolated against E. faecalis and discuss the possibility of using phages against E. faecalis biofilm in root canals.

  13. Candida albicans and Enterococcus faecalis in the gut

    PubMed Central

    Garsin, Danielle A; Lorenz, Michael C

    2013-01-01

    The fungus Candida albicans and the gram-positive bacterium Enterococcus faecalis are both normal residents of the human gut microbiome and cause opportunistic disseminated infections in immunocompromised individuals. Using a nematode infection model, we recently showed that co-infection resulted in less pathology and less mortality than infection with either species alone and this was partly explained by an interkingdom signaling event in which a bacterial-derived product inhibits hyphal morphogenesis of C. albicans. In this addendum we discuss these findings in the contest of other described bacterial-fungal interactions and recent data suggesting a potentially synergistic relationship between these two species in the mouse gut as well. We suggest that E. faecalis and C. albicans promote a mutually beneficial association with the host, in effect choosing a commensal lifestyle over a pathogenic one. PMID:23941906

  14. Sex pheromones and gene transfer in Enterococcus faecalis.

    PubMed

    Wirth, R

    2000-01-01

    Cell-density-dependent regulatory controls have been recognized in recent years to play major roles with regard to many microorganisms. In gram-negative bacteria very often N-acyl-homoserine lactones act as 'quorum-sensing' regulators, whilst gram-positive bacteria mainly use peptides to monitor their cell density. The so-called sex pheromone system of Enterococcus faecalis is just one example of the latter type of regulation. The system is a complex one; in this communication, I will discuss in particular the potential role of the peptides to also act as virulence factors.

  15. Enterococcus faecalis Inhibits Hyphal Morphogenesis and Virulence of Candida albicans

    PubMed Central

    Cruz, Melissa R.; Graham, Carrie E.; Gagliano, Bryce C.

    2013-01-01

    The Gram-positive bacterium Enterococcus faecalis and the fungus Candida albicans are both found as commensals in many of the same niches of the human body, such as the oral cavity and gastrointestinal (GI) tract. However, both are opportunistic pathogens and have frequently been found to be coconstituents of polymicrobial infections. Despite these features in common, there has been little investigation into whether these microbes affect one another in a biologically significant manner. Using a Caenorhabditis elegans model of polymicrobial infection, we discovered that E. faecalis and C. albicans negatively impact each other's virulence. Much of the negative effect of E. faecalis on C. albicans was due to the inhibition of C. albicans hyphal morphogenesis, a developmental program crucial to C. albicans pathogenicity. We discovered that the inhibition was partially dependent on the Fsr quorum-sensing system, a major regulator of virulence in E. faecalis. Specifically, two proteases regulated by Fsr, GelE and SerE, were partially required. Further characterization of the inhibitory signal revealed that it is secreted into the supernatant, is heat resistant, and is between 3 and 10 kDa. The substance was also shown to inhibit C. albicans filamentation in the context of an in vitro biofilm. Finally, a screen of an E. faecalis transposon mutant library identified other genes required for suppression of C. albicans hyphal formation. Overall, we demonstrate a biologically relevant interaction between two clinically important microbes that could affect treatment strategies as well as impact our understanding of interkingdom signaling and sensing in the human-associated microbiome. PMID:23115035

  16. Eradication of Enterococcus faecalis Biofilms on Human Dentin

    PubMed Central

    Rosen, Eyal; Tsesis, Igor; Elbahary, Shlomo; Storzi, Nimrod; Kolodkin-Gal, Ilana

    2016-01-01

    Objectives: This work assesses different methods to interfere with Enterococcus faecalis biofilms formed on human dentin slabs. Methods: First, methods are presented that select for small molecule inhibitors of biofilm targets using multi-well polystyrene biofilm plates. Next, we establish methodologies to study and interfere with biofilm formation on a medically relevant model, whereby biofilms are grown on human root dentin slabs. Results: Non-conventional D-amino acid (D-Leucine) can efficiently disperse biofilms formed on dentin slabs without disturbing planktonic growth. Cation chelators interfere with biofilm formation on dentin slabs and polystyrene surfaces, and modestly impact planktonic growth. Strikingly, sodium hypochlorite, the treatment conventionally used to decontaminate infected root canal systems, was extremely toxic to planktonic bacteria, but did not eradicate biofilm cells. Instead, it induced a viable but non-culturable state in biofilm cells when grown on dentin slabs. Conclusion: Sodium hypochlorite may contribute to bacterial persistence. A combination of the methods described here can greatly contribute to the development of biofilm inhibitors and therapies to treat Enterococcus faecalis infections formed in the root canal system. PMID:28082955

  17. Enterococcus faecalis prophage dynamics and contributions to pathogenic traits.

    PubMed

    Matos, Renata C; Lapaque, Nicolas; Rigottier-Gois, Lionel; Debarbieux, Laurent; Meylheuc, Thierry; Gonzalez-Zorn, Bruno; Repoila, Francis; Lopes, Maria de Fatima; Serror, Pascale

    2013-06-01

    Polylysogeny is frequently considered to be the result of an adaptive evolutionary process in which prophages confer fitness and/or virulence factors, thus making them important for evolution of both bacterial populations and infectious diseases. The Enterococcus faecalis V583 isolate belongs to the high-risk clonal complex 2 that is particularly well adapted to the hospital environment. Its genome carries 7 prophage-like elements (V583-pp1 to -pp7), one of which is ubiquitous in the species. In this study, we investigated the activity of the V583 prophages and their contribution to E. faecalis biological traits. We systematically analyzed the ability of each prophage to excise from the bacterial chromosome, to replicate and to package its DNA. We also created a set of E. faecalis isogenic strains that lack from one to all six non-ubiquitous prophages by mimicking natural excision. Our work reveals that prophages of E. faecalis V583 excise from the bacterial chromosome in the presence of a fluoroquinolone, and are able to produce active phage progeny. Intricate interactions between V583 prophages were also unveiled: i) pp7, coined EfCIV583 for E. faecalis chromosomal island of V583, hijacks capsids from helper phage 1, leading to the formation of distinct virions, and ii) pp1, pp3 and pp5 inhibit excision of pp4 and pp6. The hijacking exerted by EfCIV583 on helper phage 1 capsids is the first example of molecular piracy in Gram positive bacteria other than staphylococci. Furthermore, prophages encoding platelet-binding-like proteins were found to be involved in adhesion to human platelets, considered as a first step towards the development of infective endocarditis. Our findings reveal not only a role of E. faecalis V583 prophages in pathogenicity, but also provide an explanation for the correlation between antibiotic usage and E. faecalis success as a nosocomial pathogen, as fluoriquinolone may provoke release of prophages and promote gene dissemination among

  18. Enterococcal surface protein, Esp, enhances biofilm formation by Enterococcus faecalis.

    PubMed

    Tendolkar, Preeti M; Baghdayan, Arto S; Gilmore, Michael S; Shankar, Nathan

    2004-10-01

    Enterococci play a dual role in human ecology. They serve as commensal organisms of the gastrointestinal tract and are also leading causes of multiple antibiotic-resistant hospital-acquired infection. Many nosocomial infections result from the ability of microorganisms to form biofilms. The molecular mechanisms involved in enterococcal biofilm formation are only now beginning to be understood. Enterococcal surface protein, Esp, has been reported to contribute to biofilm formation by Enterococcus faecalis. Recent studies have shown that enterococci form biofilms independently of Esp expression. To precisely determine what role Esp plays in E. faecalis biofilm formation, Esp was expressed on the cell surface of genetically well-defined, natively Esp-deficient strains, and isogenic Esp-positive and Esp-deficient strains were compared for their biofilm-forming ability. The results show that Esp expression leads to a significant increase in biofilm formation, irrespective of the strain tested. The contribution of Esp to biofilm formation was found to be most pronounced in the presence of 0.5% (wt/vol) or greater glucose. These results unambiguously define Esp as a key contributor to the ability of E. faecalis to form biofilms.

  19. Enterococcal Surface Protein, Esp, Enhances Biofilm Formation by Enterococcus faecalis

    PubMed Central

    Tendolkar, Preeti M.; Baghdayan, Arto S.; Gilmore, Michael S.; Shankar, Nathan

    2004-01-01

    Enterococci play a dual role in human ecology. They serve as commensal organisms of the gastrointestinal tract and are also leading causes of multiple antibiotic-resistant hospital-acquired infection. Many nosocomial infections result from the ability of microorganisms to form biofilms. The molecular mechanisms involved in enterococcal biofilm formation are only now beginning to be understood. Enterococcal surface protein, Esp, has been reported to contribute to biofilm formation by Enterococcus faecalis. Recent studies have shown that enterococci form biofilms independently of Esp expression. To precisely determine what role Esp plays in E. faecalis biofilm formation, Esp was expressed on the cell surface of genetically well-defined, natively Esp-deficient strains, and isogenic Esp-positive and Esp-deficient strains were compared for their biofilm-forming ability. The results show that Esp expression leads to a significant increase in biofilm formation, irrespective of the strain tested. The contribution of Esp to biofilm formation was found to be most pronounced in the presence of 0.5% (wt/vol) or greater glucose. These results unambiguously define Esp as a key contributor to the ability of E. faecalis to form biofilms. PMID:15385507

  20. Antimicrobial effect of alexidine and chlorhexidine against Enterococcus faecalis infection

    PubMed Central

    Kim, Hyun-Shik; Woo Chang, Seok; Baek, Seung-Ho; Han, Seung Hyun; Lee, Yoon; Zhu, Qiang; Kum, Kee-Yeon

    2013-01-01

    A previous study demonstrated that alexidine has greater affinity for the major virulence factors of bacteria than chlorhexidine. The aim of this study was to compare the antimicrobial activity of 1% alexidine with that of 2% chlorhexidine using Enterococcus faecalis-infected dentin blocks. Sixty bovine dentin blocks were prepared and randomly divided into six groups of 10 each. E. faecalis was inoculated on 60 dentin blocks using the Luppens apparatus for 24 h and then the dentin blocks were soaked in 2% chlorhexidine or 1% alexidine solutions for 5 and 10 min, respectively. Sterile saline was used as a control. The antimicrobial efficacy was assessed by counting the number of bacteria adhering to the dentin surface and observing the degradation of bacterial shape or membrane rupture under a scanning electron microscope. Significantly fewer bacteria were observed in the 2% chlorhexidine- or 1% alexidine-soaked groups than in the control group (P<0.05). However, there was no significant difference in the number of bacteria adhering to the dentinal surface between the two experimental groups or between the two soaking time groups (P>0.05). Ruptured or antiseptic-attached bacteria were more frequently observed in the 10-min-soaked chlorhexidine and alexidine groups than in the 5-min-soaked chlorhexidine and alexidine groups. In conclusion, 10-min soaking with 1% alexidine or 2% chlorhexidine can be effective against E. faecalis infection. PMID:23492900

  1. Mechanisms of clinical resistance to fluoroquinolones in Enterococcus faecalis.

    PubMed Central

    Nakanishi, N; Yoshida, S; Wakebe, H; Inoue, M; Mitsuhashi, S

    1991-01-01

    About 10% of 100 clinical isolates of Enterococcus faecalis were resistant to greater than or equal to 25 micrograms of norfloxacin, ofloxacin, ciprofloxacin, and temafloxacin per ml. In this study, the DNA gyrase of E. faecalis was purified from a fluoroquinolone-susceptible strain (ATCC 19433) and two resistant isolates, MS16968 and MS16996. Strains MS16968 and MS16996 were 64- to 128-fold and 16- to 32-fold less susceptible, respectively, to fluoroquinolones than was ATCC 19433; MICs of nonquinolone antibacterial agents for these strains were almost equal. The DNA gyrase from ATCC 19433 had two subunits, designated A and B, with properties similar to those of DNA gyrase from other gram-positive bacteria such as Bacillus subtilis and Micrococcus luteus. Inhibition of the supercoiling activity of the enzyme from ATCC 19433 by the fluoroquinolones correlated with their antibacterial activities. In contrast, preparations of DNA gyrase from MS16968 and MS16996 were at least 30-fold less sensitive to inhibition of supercoiling by the fluoroquinolones than the gyrase from ATCC 19433 was. Experiments that combined heterologous gyrase subunits showed that the A subunit from either of the resistant isolates conferred resistance to fluoroquinolones. These findings indicate that an alteration in the gyrase A subunit is the major contributor to fluoroquinolone resistance in E. faecalis clinical isolates. A difference in drug uptake may also contribute to the level of fluoroquinolone resistance in these isolates. Images PMID:1656852

  2. Efficacy of contemporary and novel Intracanal medicaments against enterococcus faecalis.

    PubMed

    Marickar, R F; Geetha, R V; Neelakantan, P

    2014-01-01

    To compare the antibacterial activity of propolis (30% in methyl cellulose), curcumin (2.5mg/mL of methyl cellulose), 2% chlorhexidine gel (CHX), 2% metronidazole gel (MZ) and a mixture of 2% CHX and 2% MZ against Enterococcus faecalis in vitro. Calcium hydroxide served as the control. The inhibitory effect of the medicaments on E. faecalis was determined by the agar diffusion test and tube dilution test. The rate of bactericidal activity was evaluated by the time-kill assay. Zones of inhibition data and time to kill data were statistically analyzed by ANOVA and post hoc Tukey test (P=0.05). CHX demonstrated the highest mean zone of inhibition (34 ± 3mm) which was not significantly different (P ≥ 0.05) from curcumin (33 ± 2mm) and MZ (30 ± 2mm). Calcium hydroxide showed only contact inhibition. The time kill assay showed a time dependent action of each medicament. All tested agents except calcium hydroxide demonstrated significant reduction of viable bacteria at the time periods. The intracanal medicaments tested brought about a time dependent antibacterial effect on E.faecalis.

  3. A newly isolated probiotic Enterococcus faecalis strain from vagina microbiota enhances apoptosis of human cancer cells.

    PubMed

    Nami, Y; Abdullah, N; Haghshenas, B; Radiah, D; Rosli, R; Yari Khosroushahi, A

    2014-08-01

    This study aimed to describe probiotic properties and bio-therapeutic effects of newly isolated Enterococcus faecalis from the human vaginal tract. The Enterococcus faecalis strain was originally isolated from the vaginal microbiota of Iranian women and was molecularly identified using 16SrDNA gene sequencing. Some biochemical methodologies were preliminarily used to characterize the probiotic potential of Ent. faecalis, including antibiotic susceptibility, antimicrobial activity, as well as acid and bile resistance. The bio-therapeutic effects of this strain's secreted metabolites on four human cancer cell lines (AGS, HeLa, MCF-7 and HT-29) and one normal cell line (HUVEC) were evaluated by cytotoxicity assay and apoptosis scrutiny. The characterization results demonstrated into the isolated bacteria strain revealed probiotic properties, such as antibiotic susceptibility, antimicrobial activity and resistance under conditions similar to those in the gastrointestinal tract. Results of bio-therapeutic efficacy assessments illustrated acceptable apoptotic effects on four human cancer cell lines and negligible side effects on assayed normal cell line. Our findings revealed that the apoptotic effect of secreted metabolites mainly depended on proteins secreted by Ent. faecalis on different cancer cells. These proteins can induce the apoptosis of cancer cells. The metabolites produced by this vaginal Ent. faecalis strain can be used as alternative pharmaceutical compounds with promising therapeutic indices because they are not cytotoxic to normal mammalian cells. Accordingly, the physicochemical, structural and functional properties of the secreted anticancer substances should be further investigated before using them as anticancer therapeutics. This study aim to screen total bacterial secreted metabolites as a wealthy source to find the new active compounds to introduce as anticancer therapeutics in the future. © 2014 The Society for Applied Microbiology.

  4. Distribution of aminoglycoside resistance genes in recent clinical isolates of Enterococcus faecalis, Enterococcus faecium and Enterococcus avium.

    PubMed Central

    Kobayashi, N.; Alam, M.; Nishimoto, Y.; Urasawa, S.; Uehara, N.; Watanabe, N.

    2001-01-01

    Aminoglycoside modifying enzymes (AMEs) are major factors which confer aminoglycoside resistance on bacteria. Distribution of genes encoding seven AMEs was investigated by multiplex PCR for 279 recent clinical isolates of enterococci derived from a university hospital in Japan. The aac(6')-aph(2"), which is related to high level gentamicin resistance, was detected at higher frequency in Enterococcus faecalis (42.5%) than in Enterococcus faecium (4.3%). Almost half of E. faecalis and E. faecium isolates possessed ant(6)-Ia and aph(3')-IIIa. The profile of AME gene(s) detected most frequently in individual strains of E. faecalis was aac(6')aph(2") + ant(6)-Ia + aph(3')-IIIa, and isolates with this profile showed high level resistance to both gentamicin and streptomycin. In contrast, AME gene profiles of aac(6')-Ii+ ant(6)-Ia+aph(3')-IIIa, followed by aac(6')-Ii alone, were predominant in E. faecium. Only one AME gene profile of ant(6)-Ia+aph(3')-IIIa was found in Enterococcus avium. The ant(4')-Ia and ant(9)-Ia, which have been known to be distributed mostly among Staphylococcus aureus strains, were detected in a few enterococcal strains. An AME gene aph(2")-Ic was not detected in any isolates of the three enterococcal species. These findings indicated a variety of distribution profiles of AME genes among enterococci in our study site. PMID:11349969

  5. Pulmonary hypertension syndrome in broilers caused by Enterococcus faecalis.

    PubMed

    Tankson, J D; Thaxton, J P; Vizzier-Thaxton, Y

    2001-10-01

    A field strain of Enterococcus faecalis was administered to broiler chicks at doses of 0, 3 x 10(6), 1.5 x 10(7), and 2 x 10(7) bacteria/bird either intra-abdominally or intravenously. In trials 1 to 3, birds were reared communally in a broiler house on pine shaving litter. In trial 4, challenged and control birds were maintained in separate isolation rooms in metal cages with raised wire floors. Challenged birds exhibited a characteristic cavity or depression in the external wall of the right ventricle. A subjective scoring system was devised to quantify challenge effects by assigning each heart a score of 1 to 4. The average number of birds, over all trials and over all dose levels, exhibiting the ventricular cavity was 93%. This value in controls was 5%. The average heart score for challenged birds was 3.1, and that for controls was 0.20. Heart scores of challenged and control chicks were not different in birds reared communally or in separate isolation rooms. Additionally, both routes of administration were equally effective. Results suggest that challenge with E. faecalis caused pulmonary hypertension.

  6. Susceptibilties of two Enterococcus faecalis phenotypes to root canal medications.

    PubMed

    Abdullah, Mariam; Ng, Yuan-Ling; Gulabivala, Kishor; Moles, David R; Spratt, David A

    2005-01-01

    This study aimed to investigate and compare the efficacy of selected root canal irrigants and a medicament on a clinical isolate of Enterococcus faecalis grown as biofilm or planktonic suspension phenotype. A cell-dense pellet "presentation" prepared from planktonic phenotype was also tested. Each bacterial presentation was exposed to calcium hydroxide (pH 12.3), 0.2% chlorhexidine gluconate, 17% ethylene-diamine-tetra-acetic acid, 10% povidone iodine, or 3.0% sodium hypochlorite (NaOCl) for a range of time periods (1, 2, 4, 8, 15, 30, and 60 min). Phosphate buffered saline was used as a control agent. The difference in gradients of bacterial killing among the biofilm, planktonic suspension or pellet presentation was significant (p < 0.05) and dependent upon the test agent except in the case of NaOCl and calcium hydroxide where no difference could be detected. NaOCl was the most effective agent and achieved 100% kills for all presentations of E. faecalis after a 2 min contact time.

  7. In vitro inactivation of Enterococcus faecalis with a led device.

    PubMed

    D'Ercole, S; Spoto, G; Trentini, P; Tripodi, D; Petrini, M

    2016-07-01

    Non-coherent light-emitting diodes (LEDs) are effective in a large variety of clinical indications; however, the bactericidal activity of LEDs is unclear, although the effectiveness of such lights is well known. Currently, no studies have examined the effects of NIR-LED on bacteria. The aims of this study were to verify the antibacterial activity of 880-nm LED irradiation on a bacterial suspension of Enterococcus faecalis and to compare it with the actions of sodium hypochlorite (NaOCl) and the concurrent use of both treatments. Before we proceeded with the main experiment, we first performed preliminary tests to evaluate the influence of such parameters as the distance of irradiation, the energy density, the irradiation time and the presence of photosensitizers on the antimicrobial effects of LEDs. After treatment, the colony forming units per milliliter (CFU/mL) was recorded and the data were submitted to ANOVA and Bonferroni post hoc tests at a level of significance of 5%. The results showed that LED irradiation, at the parameters used, is able to significantly decrease E. faecalis viability in vitro. The total inhibition of E. faecalis was obtained throughout concurrent treatment of LED and NaOCl (1%) for 5min. The same antimicrobial activity was confirmed in all of the experiments (p<0.05), but no statistically significant differences were found by varying such parameters as the distance of irradiation (from 0.5mm to 10mm), energy density (from 2.37 to 8.15mJ/s), irradiation time (from 5min to 20min) or by adding toluidine blue O (TBO).

  8. Draft Genome Sequence of an Enterococcus faecalis ATCC 19433 Siphovirus Isolated from Raw Domestic Sewage.

    PubMed

    Santiago-Rodriguez, Tasha M; Ly, Melissa; Pride, David T; Toranzos, Gary A

    2017-01-19

    We previously isolated and characterized an Enterococcus faecalis ATCC 19433 siphovirus from raw domestic sewage as a viral indicator of human fecal pollution. Here, we report the draft genome sequence of this bacteriophage.

  9. Antimicrobial resistance and virulence of Enterococcus faecalis isolated from retail food

    USDA-ARS?s Scientific Manuscript database

    Although enterococci are considered opportunistic nosocomial pathogens, their contribution to food-borne illnesses via dissemination through retail food remains undefined. In this study, prevalence and association of antimicrobial resistance and virulence factors of 80 Enterococcus faecalis isolate...

  10. Draft Genome Sequence of an Enterococcus faecalis Strain Isolated from a Neonatal Blood Sepsis Patient

    PubMed Central

    Kropp, K. A.; Lucid, A.; Carroll, J.; Belgrudov, V.; Walsh, P.; Kelly, B.; Smith, C.; Dickinson, P.; O’Driscoll, A.; Templeton, K.; Ghazal, P.

    2014-01-01

    Herein, we report the draft genome sequence of Enterococcus faecalis ED-NGS-1009, cultivated from a blood sample taken from a neonatal sepsis patient at the Royal Infirmary in Edinburgh, Scotland, United Kingdom. PMID:25212626

  11. Draft Genome Sequence of an Enterococcus faecalis ATCC 19433 Siphovirus Isolated from Raw Domestic Sewage

    PubMed Central

    Ly, Melissa; Pride, David T.; Toranzos, Gary A.

    2017-01-01

    ABSTRACT We previously isolated and characterized an Enterococcus faecalis ATCC 19433 siphovirus from raw domestic sewage as a viral indicator of human fecal pollution. Here, we report the draft genome sequence of this bacteriophage. PMID:28104647

  12. Outbreak of mastitis in sheep caused by multi-drug resistant Enterococcus faecalis in Sardinia, Italy.

    PubMed

    Sanciu, G; Marogna, G; Paglietti, B; Cappuccinelli, P; Leori, G; Rappelli, P

    2013-03-01

    An outbreak of infective mastitis due to Enterococcus faecalis occurred in an intensive sheep farm in north Sardinia (Italy). E. faecalis, which is only rarely isolated from sheep milk, was unexpectedly found in 22·3% of positive samples at microbiological examination. Forty-five out of the 48 E. faecalis isolates showed the same multi-drug resistance pattern (cloxacillin, streptomycin, kanamycin, clindamycin, oxytetracycline). E. faecalis isolates were analysed by pulsed-field gel electrophoresis, and all 45 multi-drug resistant strains showed an indistinguishable macrorestiction profile, indicating their clonal origin. To our knowledge, this is the first report of an outbreak of mastitis in sheep caused by E. faecalis.

  13. Purification and characterization of enterocin 4, a bacteriocin produced by Enterococcus faecalis INIA 4.

    PubMed Central

    Joosten, H M; Nunez, M; Devreese, B; Van Beeumen, J; Marugg, J D

    1996-01-01

    A simple two-step procedure was developed to obtain pure enterocin 4, a bacteriocin produced by Enterococcus faecalis INIA 4. Chemical and genetic characterization revealed that the primary structure of enterocin 4 is identical to that of peptide antibiotic AS-48 from Enterococcus faecalis S-48. In contrast to the reported inhibitory spectrum of AS-48, enterocin 4 displayed no activity against gram-negative bacteria. PMID:8900014

  14. The effect of berberine hydrochloride on Enterococcus faecalis biofilm formation and dispersion in vitro.

    PubMed

    Chen, Lihua; Bu, Qianqian; Xu, Huan; Liu, Yuan; She, Pengfei; Tan, Ruichen; Wu, Yong

    2016-01-01

    Enterococcus faecalis (E. faecalis) is one of the major causes of biofilm infections. Berberine hydrochloride (BBH) has diverse pharmacological effects; however, the effects and mechanisms of BBH on E. faecalis biofilm formation and dispersion have not been reported. In this study, 99 clinical isolates from the urine samples of patients with urinary tract infections (UTIs) were collected and identified. Ten strains of E. faecalis with biofilm formation ability were studied. BBH inhibited E. faecalis biofilm formation and promoted the biofilm dispersion of E. faecalis. In addition, sortase A and esp expression levels were elevated during early E. faecalis biofilm development, whereas BBH significantly reduced their expression levels. The results of this study indicated that BBH effectively prevents biofilm formation and promotes biofilm dispersion in E. faecalis, most likely by inhibiting the expressions of sortase A and esp.

  15. REAL-TIME PCR METHOD TO DETECT ENTEROCOCCUS FAECALIS IN WATER

    EPA Science Inventory

    A 16S rDNA real-time PCR method was developed to detect Enterococcus faecalis in water samples. The dynamic range for cell detection spanned five logs and the detection limit was determined to be 6 cfu/reaction. The assay was capable of detecting E. faecalis cells added to biof...

  16. Mechanisms for Photoinactivation of Enterococcus faecalis in Seawater

    PubMed Central

    Sassoubre, Lauren M.; Nelson, Kara L.

    2012-01-01

    Field studies in fresh and marine waters consistently show diel fluctuations in concentrations of enterococci, indicators of water quality. We investigated sunlight inactivation of Enterococcus faecalis to gain insight into photoinactivation mechanisms and cellular responses to photostress. E. faecalis bacteria were exposed to natural sunlight in clear, filtered seawater under both oxic and anoxic conditions to test the relative importance of oxygen-mediated and non-oxygen-mediated photoinactivation mechanisms. Multiple methods were used to assess changes in bacterial concentration, including cultivation, quantitative PCR (qPCR), propidium monoazide (PMA)-qPCR, LIVE/DEAD staining using propidium iodide (PI), and cellular activity, including ATP concentrations and expression of the superoxide dismutase-encoding gene, sodA. Photoinactivation, based on numbers of cultivable cells, was faster in oxic than in anoxic microcosms exposed to sunlight, suggesting that oxygen-mediated photoinactivation dominated. There was little change in qPCR signal over the course of the experiment, demonstrating that the nucleic acid targets were not damaged to a significant extent. The PMA-qPCR signal was also fairly stable, consistent with the observation that the fraction of PI-permeable cells was constant. Thus, damage to the membrane was minimal. Microbial ATP concentrations decreased in all microcosms, particularly the sunlit oxic microcosms. The increase in relative expression of the sodA gene in the sunlit oxic microcosms suggests that cells were actively responding to oxidative stress. Dark repair was not observed. This research furthers our understanding of photoinactivation mechanisms and the conditions under which diel fluctuations in enterococci can be expected in natural and engineered systems. PMID:22941072

  17. In vitro activity of Amazon plant extracts against Enterococcus faecalis

    PubMed Central

    de Castilho, Adriana Lígia; da Silva, Juliana Paola Correa; Saraceni, Cintia Helena Coury; Díaz, Ingrit Elida Collantes; Paciencia, Mateus Luís Barradas; Varella, Antonio Drauzio; Suffredini, Ivana Barbosa

    2014-01-01

    Previous studies analyzing 2,200 plant extracts indicated anti-enterococcal activity in 25 extracts obtained from Brazilian forests’ plants. In the present study, these extracts were subjected to microdilution broth assay (MDBA) and disk diffusion assay (DDA) using planktonic Enterococcus faecalis ATCC® 29212™ and were submitted to phytochemical analysis in TLC and HPLC. Three extracts obtained from Ipomoea alba (MIC < 40 μg/mL), Diclinanona calycina (MIC ≤ 40 μg/mL) and Moronobea coccinea (40 < MIC < 80 μg/mL; MBC = 80 μg/mL) showed significant bactericidal activity in the MDBA and four extracts obtained from I. alba (14.04 ± 0.55 mm diameter) S. globulifera (14.43 ± 0.33 mm and 12.18 ± 0.28 mm diameter) and Connarus ruber var. ruber (13.13 ± 0.18 mm diameter) were active in DDA. Residues H2O obtained from Psidium densicomum (mean of 16.78 mm diameter) and from Stryphnodendron pulcherrimum (mean of 15.97 mm diameter) have shown an improved antibacterial activity after fractionation if compared to that obtained from the respective crude extracts. Antioxidant activity was observed in some residues of the active extracts. TLC analysis showed that phenolic compounds are likely to be found in active extracts. Three molecules were isolated from S. globulifera and were identified by 13C NMR lupeol, α-amyrin and 3β-hydroxyglutin-5-ene. The present chemical and biological findings suggest that these extracts are a potential source of new anti-Enterococcus compounds to be introduced in endodontic therapy. PMID:25477906

  18. Convergent transcription confers a bistable switch in Enterococcus faecalis conjugation.

    PubMed

    Chatterjee, Anushree; Johnson, Christopher M; Shu, Che-Chi; Kaznessis, Yiannis N; Ramkrishna, Doraiswami; Dunny, Gary M; Hu, Wei-Shou

    2011-06-07

    Convergent gene pairs with head-to-head configurations are widespread in both eukaryotic and prokaryotic genomes and are speculated to be involved in gene regulation. Here we present a unique mechanism of gene regulation due to convergent transcription from the antagonistic prgX/prgQ operon in Enterococcus faecalis controlling conjugative transfer of the antibiotic resistance plasmid pCF10 from donor cells to recipient cells. Using mathematical modeling and experimentation, we demonstrate that convergent transcription in the prgX/prgQ operon endows the system with the properties of a robust genetic switch through premature termination of elongating transcripts due to collisions between RNA polymerases (RNAPs) transcribing from opposite directions and antisense regulation between complementary counter-transcripts. Evidence is provided for the presence of truncated RNAs resulting from convergent transcription from both the promoters that are capable of sense-antisense interactions. A mathematical model predicts that both RNAP collision and antisense regulation are essential for a robust bistable switch behavior in the control of conjugation initiation by prgX/prgQ operons. Moreover, given that convergent transcription is conserved across species, the mechanism of coupling RNAP collision and antisense interaction is likely to have a significant regulatory role in gene expression.

  19. Structural proteins of Enterococcus faecalis bacteriophage ϕEf11

    PubMed Central

    Stevens, Roy H.; Zhang, Hongming; Hsiao, Chaiwing; Kachlany, Scott; Tinoco, Eduardo M. B.; DePew, Jessica; Fouts, Derrick E.

    2016-01-01

    ABSTRACT ϕEf11, a temperate Siphoviridae bacteriophage, was isolated by induction from a root canal isolate of Enterococcus faecalis. Sequence analysis suggested that the ϕEf11 genome included a contiguous 8 gene module whose function was related to head structure assembly and another module of 10 contiguous genes whose products were responsible for tail structure assembly. SDS-PAGE analysis of virions of a ϕEf11 derivative revealed 11 well-resolved protein bands. To unify the deduced functional gene assignments emanating from the DNA sequence data, with the structural protein analysis of the purified virus, 6 of the SDS-PAGE bands were subjected to mass spectrometry analysis. 5 of the 6 protein bands analyzed by mass spectrometry displayed identical amino acid sequences to those predicted to be specified by 4 of the ORFs identified in the ϕEf11 genome. These included: ORF8 (predicted scaffold protein), ORF10 (predicted major head protein), ORF15 (predicted major tail protein), and ORF23 (presumptive antireceptor). PMID:28090386

  20. Rapid Kill—Novel Endodontic Sealer and Enterococcus faecalis

    PubMed Central

    Zaltsman, Nathan; Houri-Haddad, Yael; Abramovitz, Itzhak; Davidi, Michael Perez; Weiss, Ervin I.

    2013-01-01

    With growing concern over bacterial resistance, the identification of new antimicrobial means is paramount. In the oral cavity microorganisms are essential to the development of periradicular diseases and are the major causative factors associated with endodontic treatment failure. As quaternary ammonium compounds have the ability to kill a wide array of bacteria through electrostatic interactions with multiple anionic targets on the bacterial surface, it is likely that they can overcome bacterial resistance. Melding these ideas, we investigated the potency of a novel endodontic sealer in limiting Enterococcus faecalis growth. We used a polyethyleneimine scaffold to synthesize nano-sized particles, optimized for incorporation into an epoxy-based endodontic sealer. The novel endodontic sealer was tested for its antimicrobial efficacy and evaluated for biocompatibility and physical eligibility. Our results show that the novel sealer foundation affixes the nanoparticles, achieving surface bactericidal properties, but at the same time impeding nanoparticle penetration into eukaryotic cells and thereby mitigating a possible toxic effect. Moreover, adequate physical properties are maintained. The nanosized quaternary amine particles interact within minutes with bacteria, triggering cell death across wide pH values. Throughout this study we demonstrate a new antibacterial perspective for endodontic sealers; a novel antibacterial, effective and safe antimicrobial means. PMID:24223159

  1. Enterococcus faecalis Enhances Cell Proliferation through Hydrogen Peroxide-Mediated Epidermal Growth Factor Receptor Activation

    PubMed Central

    Boonanantanasarn, Kanitsak; Gill, Ann Lindley; Yap, YoonSing; Jayaprakash, Vijayvel; Sullivan, Maureen A.

    2012-01-01

    Enterococcus faecalis is a member of the intestinal and oral microbiota that may affect the etiology of colorectal and oral cancers. The mechanisms by which E. faecalis may contribute to the initiation and progression of these cancers remain uncertain. Epidermal growth factor receptor (EGFR) signaling is postulated to play a crucial role in oral carcinogenesis. A link between E. faecalis and EGFR signaling in oral cancer has not been elucidated. The present study aimed to evaluate the association between E. faecalis and oral cancer and to determine the underlying mechanisms that link E. faecalis to EGFR signaling. We report the high frequency of E. faecalis infection in oral tumors and the clinical association with EGFR activation. Using human oral cancer cells, we support the clinical findings and demonstrate that E. faecalis can induce EGFR activation and cell proliferation. E. faecalis activates EGFR through production of H2O2, a signaling molecule that activates several signaling pathways. Inhibitors of H2O2 (catalase) and EGFR (gefitinib) significantly blocked E. faecalis-induced EGFR activation and cell proliferation. Therefore, E. faecalis infection of oral tumor tissues suggests a possible association between E. faecalis infection and oral carcinogenesis. Interaction of E. faecalis with host cells and production of H2O2 increase EGFR activation, thereby contributing to cell proliferation. PMID:22851748

  2. Complete Genome Sequence of Bacteriophage BC-611 Specifically Infecting Enterococcus faecalis Strain NP-10011

    PubMed Central

    Horiuchi, Tomohiro; Sakka, Makiko; Hayashi, Atsushi; Shimada, Takashi; Kimura, Tetsuya

    2012-01-01

    Enterococcus faecalis is an opportunistic pathogen that causes serious infections in humans and animals and is also an important bacterium for dairy and probiotic supplement production. Therefore, bacteriophages infecting E. faecalis may be useful for phage therapy against multidrug-resistant strains or may threaten industrial fermentation. We isolated a virulent Siphoviridae bacteriophage, BC-611, specifically infecting E. faecalis strain NP-10011 but not infecting other E. faecalis strains or other enterococci. Although the genome sequence of BC-611 resembled that of enterococcal bacteriophage SAP6, BC-611 was marked by its narrow host specificity. PMID:22879611

  3. Biocide and antibiotic resistance of Enterococcus faecalis and Enterococcus faecium isolated from the swine meat chain.

    PubMed

    Rizzotti, Lucia; Rossi, Franca; Torriani, Sandra

    2016-12-01

    In this study nine strains of Enterococcus faecalis and 12 strains of Enterococcus faecium, isolated from different sample types in the swine meat chain and previously characterized for the presence of antibiotic resistance genes, were examined for phenotypic tolerance to seven biocides (chlorexidine, benzalkonium chloride, triclosan, sodium hypochlorite, 2-propanol, formaldehyde and hydrogen peroxide) and resistance to nine antibiotics (ampicillin, vancomycin, gentamicin, kanamycin, streptomycin, erythromycin, clindamycin, tetracycline and chloramphenicol). Moreover, the presence of efflux system encoding genes qacA/B, qacC, qacE, qacEΔ1, emeA, and stress response genes, sigV and gsp65, involved in the tolerance to biocides, was analysed. Most strains were not tolerant to the biocides, but showed minimum inhibitory concentrations (MICs) higher than the recommended cut-off values for all the antibiotics tested, except for vancomycin and chloramphenicol. Only weak correlations, if any, were found between biocide and antibiotic resistance data. One E. faecalis strain was tolerant to triclosan and one E. faecium strain, with higher tolerance to chlorexidine than the other strains tested, was found to carry a qacA/B gene. Our results indicated that phenotypic resistance to antibiotics is very frequent in enterococcal isolates from the swine meat chain, but phenotypic tolerance to biocides is not common. On the other hand, the gene qacA/B was found for the first time in the species E. faecium, an indication of the necessity to adopt measures suitable to control the spread of biocide resistance determinants among enterococci.

  4. Influence of ultrasonic activation on photodynamic therapy over root canal system infected with Enterococcus faecalis--an in vitro study.

    PubMed

    Ghinzelli, Guilherme Cavagnoli; Souza, Matheus Albino; Cecchin, Doglas; Farina, Ana Paula; de Figueiredo, José Antônio Poli

    2014-12-01

    The purpose of this study was to evaluate, in vitro, the influence of ultrasonic activation on photodynamic therapy over root canal system infected with Enterococcus faecalis. The root canals of 50 single-rooted human extracted teeth were enlarged up to a file 60, autoclaved, inoculated with Enterococcus faecalis and incubated for 30 days. The samples were divided into five groups (n=10) according to the protocol of decontamination: G1 (control group) - no procedure was performed; G2 - photosensitizer (0.01% methylene blue); G3 - ultrasonic activation of photosensitizer (0.01% methylene blue); G4 - photodynamic therapy with no ultrasonic activation; and G5 - photodynamic therapy with ultrasonic activation. Microbiological tests (CFU counting) and scanning electron microscopy (SEM) were performed to evaluate and illustrate, respectively, the effectiveness of proposed treatments. Data were subjected to one-way ANOVA followed by post hoc Tukey test (α=0.05). The microbiological test demonstrated that G5 (photodynamic therapy with ultrasonic activation) showed the lowest mean contamination (3.17 log CFU/mL), which was statistically different from all other groups (p<0.05). G4 (photodynamic therapy) showed a mean of contamination of 3.60 log CFU/mL, which was statistically different from groups 1, 2 and 3 (p<0.05). The use of ultrasonic activation on photodynamic therapy improved its potential for decontamination, resulting in the higher elimination Enterococcus faecalis from the root canal space. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Molecular Mechanism of Quorum-Sensing in Enterococcus faecalis: Its Role in Virulence and Therapeutic Approaches

    PubMed Central

    Ali, Liaqat; Goraya, Mohsan Ullah; Arafat, Yasir; Ajmal, Muhammad; Chen, Ji-Long; Yu, Daojin

    2017-01-01

    Quorum-sensing systems control major virulence determinants in Enterococcus faecalis, which causes nosocomial infections. The E. faecalis quorum-sensing systems include several virulence factors that are regulated by the cytolysin operon, which encodes the cytolysin toxin. In addition, the E. faecalis Fsr regulator system controls the expression of gelatinase, serine protease, and enterocin O16. The cytolysin and Fsr virulence factor systems are linked to enterococcal diseases that affect the health of humans and other host models. Therefore, there is substantial interest in understanding and targeting these regulatory pathways to develop novel therapies for enterococcal infection control. Quorum-sensing inhibitors could be potential therapeutic agents for attenuating the pathogenic effects of E. faecalis. Here, we discuss the regulation of cytolysin, the LuxS system, and the Fsr system, their role in E. faecalis-mediated infections, and possible therapeutic approaches to prevent E. faecalis infection. PMID:28467378

  6. Dissemination of Enterococcus faecalis and Enterococcus faecium in a ricotta processing plant and evaluation of pathogenic and antibiotic resistance profiles.

    PubMed

    Fernandes, Meg da Silva; Fujimoto, Graciela; de Souza, Leandro Pio; Kabuki, Dirce Yorika; da Silva, Márcio José; Kuaye, Arnaldo Yoshiteru

    2015-04-01

    In this work, the sources of contamination by Enterococcus spp. in a ricotta processing line were evaluated. The isolated strains were tested for virulence genes (gelE, cylA,B, M, esp, agg, ace, efaA, vanB), expression of virulence factors (hemolysin and gelatinase), and the resistance to 10 different antibiotics. Enterococcus faecium and Enterococcus faecalis were subjected to discriminatory identification by intergenic spacer region (ITS)-polymerase chain reaction and sequencing of the ITS region. The results showed that Enterococcus spp. was detected in the raw materials, environment samples and the final product. None of the 107 Enterococcus isolates were completely free from all virulence genes considered. A fraction of 21.5% of the isolates containing all of the genes of the cylA, B, M operon also expressed β-hemolysis. Most of the isolates showed the gelE gene, but only 9.3% were able to hydrolyze gelatin. In addition, 23.5% of the observed Enterococcus isolates had the vanB gene but were susceptible to vancomycin in vitro. The dissemination of antibiotic-resistant enterococci was revealed in this study: 19.3% of the E. faecium samples and 78.0% of the E. faecalis samples were resistant to at least one of the antibiotics tested. Sequencing of region discriminated 5 and 7 distinct groups among E. faecalis and E. faecium, respectively. Although some similarity was observed among some of the isolates, all E. faecalis and E. faecium isolates had genetic differences both in the ITS region and in the virulence profile, which makes them different from each other.

  7. Antibiotic resistance patterns and genetic relatedness of Enterococcus faecalis and Enterococcus faecium isolated from military working dogs in Korea.

    PubMed

    Bang, Kiman; An, Jae-Uk; Kim, Woohyun; Dong, Hee-Jin; Kim, Junhyung; Cho, Seongbeom

    2017-06-30

    Enterococcus spp. are normally present in the gastrointestinal tracts of animals and humans, but can cause opportunistic infections that can be transmitted to other animals or humans with integrated antibiotic resistance. To investigate if this is a potential risk in military working dogs (MWDs), we analyzed antibiotic resistance patterns and genetic relatedness of Enterococcus spp. isolated from fecal samples of MWDs of four different age groups. Isolation rates of Enterococcus spp., Enterococcus (E.) faecalis, and E. faecium, were 87.7% (57/65), 59.6% (34/57), and 56.1% (32/57), respectively, as determined by bacterial culture and multiplex PCR. The isolation rate of E. faecalis gradually decreased with age (puppy, 100%; adolescent, 91.7%; adult, 36.4%; and senior, 14.3%). Rates of resistance to the antibiotics ciprofloxacin, gentamicin, streptomycin, sulfamethoxazole/trimethoprim, imipenem, and kanamycin among Enterococcus spp. increased in adolescents and adults and decreased in senior dogs, with some isolates having three different antibiotic resistance patterns. There were indistinguishable pulsed-field gel electrophoresis patterns among the age groups. The results suggest that Enterococcus is horizontally transferred, regardless of age. As such, periodic surveillance studies should be undertaken to monitor changes in antibiotic resistance, which may necessitate modification of antibiotic regimens to manage antibiotic resistance transmission.

  8. The Enterococcal Surface Protein, Esp, Is Involved in Enterococcus faecalis Biofilm Formation

    PubMed Central

    Toledo-Arana, Alejandro; Valle, Jaione; Solano, Cristina; Arrizubieta, María Jesús; Cucarella, Carme; Lamata, Marta; Amorena, Beatriz; Leiva, José; Penadés, José Rafael; Lasa, Iñigo

    2001-01-01

    The enterococcal surface protein, Esp, is a high-molecular-weight surface protein of unknown function whose frequency is significantly increased among infection-derived Enterococcus faecalis isolates. In this work, a global structural similarity was found between Bap, a biofilm-associated protein of Staphylococcus aureus, and Esp. Analysis of the relationship between the presence of the Esp-encoding gene (esp) and the biofilm formation capacity in E. faecalis demonstrated that the presence of the esp gene is highly associated (P < 0.0001) with the capacity of E. faecalis to form a biofilm on a polystyrene surface, since 93.5% of the E. faecalis esp-positive isolates were capable of forming a biofilm. Moreover, none of the E. faecalis esp-deficient isolates were biofilm producers. Depending on the E. faecalis isolate, insertional mutagenesis of esp caused either a complete loss of the biofilm formation phenotype or no apparent phenotypic defect. Complementation studies revealed that Esp expression in an E. faecalis esp-deficient strain promoted primary attachment and biofilm formation on polystyrene and polyvinyl chloride plastic from urine collection bags. Together, these results demonstrate that (i) biofilm formation capacity is widespread among clinical E. faecalis isolates, (ii) the biofilm formation capacity is restricted to the E. faecalis strains harboring esp, and (iii) Esp promotes primary attachment and biofilm formation of E. faecalis on abiotic surfaces. PMID:11571153

  9. The enterococcal surface protein, Esp, is involved in Enterococcus faecalis biofilm formation.

    PubMed

    Toledo-Arana, A; Valle, J; Solano, C; Arrizubieta, M J; Cucarella, C; Lamata, M; Amorena, B; Leiva, J; Penadés, J R; Lasa, I

    2001-10-01

    The enterococcal surface protein, Esp, is a high-molecular-weight surface protein of unknown function whose frequency is significantly increased among infection-derived Enterococcus faecalis isolates. In this work, a global structural similarity was found between Bap, a biofilm-associated protein of Staphylococcus aureus, and Esp. Analysis of the relationship between the presence of the Esp-encoding gene (esp) and the biofilm formation capacity in E. faecalis demonstrated that the presence of the esp gene is highly associated (P < 0.0001) with the capacity of E. faecalis to form a biofilm on a polystyrene surface, since 93.5% of the E. faecalis esp-positive isolates were capable of forming a biofilm. Moreover, none of the E. faecalis esp-deficient isolates were biofilm producers. Depending on the E. faecalis isolate, insertional mutagenesis of esp caused either a complete loss of the biofilm formation phenotype or no apparent phenotypic defect. Complementation studies revealed that Esp expression in an E. faecalis esp-deficient strain promoted primary attachment and biofilm formation on polystyrene and polyvinyl chloride plastic from urine collection bags. Together, these results demonstrate that (i) biofilm formation capacity is widespread among clinical E. faecalis isolates, (ii) the biofilm formation capacity is restricted to the E. faecalis strains harboring esp, and (iii) Esp promotes primary attachment and biofilm formation of E. faecalis on abiotic surfaces.

  10. Role of a qnr-Like Gene in the Intrinsic Resistance of Enterococcus faecalis to Fluoroquinolones▿

    PubMed Central

    Arsène, Stéphanie; Leclercq, Roland

    2007-01-01

    Fluoroquinolones are poorly active against enterococci. Recently, plasmid-borne resistance to fluoroquinolones due to the qnr gene was reported in members of the Enterobacteriaceae family. The gene encodes a pentapeptide repeat protein that protects DNA gyrase from inhibition by fluoroquinolones. We have identified in the genome of Enterococcus faecalis V583 a qnr-like gene, named E. faecalis qnr (qnrE. faecalis), encoding a putative pentapeptide repeat protein that shares 25% identity with Qnr. To assess its potential role in the intrinsic resistance of E. faecalis to fluoroquinolones, qnrE. faecalis was inactivated in E. faecalis JH2-2 by insertion of the thermosensitive vector pG1KT. This strain was then complemented with qnrE. faecalis cloned in the multicopy plasmid pORI23. The effects of its overexpression were also studied. Inactivation of the qnrE. faecalis gene resulted in twofold decreases in the MICs of ofloxacin and ciprofloxacin. When the gene was complemented or overexpressed, MICs of fluoroquinolones increased four- to nine-fold, leading to MICs of ofloxacin and ciprofloxacin equal to 32 μg/ml and 8 μg/ml, respectively. The E. faecalis Qnr (QnrE. faecalis) protein was produced and purified. QnrE. faecalis protein protected Escherichia coli DNA gyrase from inhibition by ofloxacin. The qnrE. faecalis gene was then introduced into E. coli DH10B, Staphylococcus aureus RN4220, and Lactococcus lactis IL-1419 to study its heterologous expression. MICs of the various fluoroquinolones tested increased 4- to 16-fold, showing that QnrE. faecalis conferred resistance to fluoroquinolones in various bacterial backgrounds. Overexpression of qnrE. faecalis in enterococci or mobilization of the gene to other bacterial species may be anticipated as a possible new mechanism for fluoroquinolone resistance. PMID:17620379

  11. Differences in antibiotic resistance patterns of Enterococcus faecalis and Enterococcus faecium strains isolated from farm and pet animals.

    PubMed

    Butaye, P; Devriese, L A; Haesebrouck, F

    2001-05-01

    The prevalence of acquired resistance in 146 Enterococcus faecium and 166 Enterococcus faecalis strains from farm and pet animals, isolated in 1998 and 1999 in Belgium, against antibiotics used for growth promotion and for therapy was determined. Acquired resistance against flavomycin and monensin, two antibiotics used solely for growth promotion, was not detected. Avoparcin (glycopeptide) resistance was found sporadically in E. faecium only. Avilamycin resistance was almost exclusively seen in strains from farm animals. Resistance rates were higher in E. faecium strains from broiler chickens than in strains from other animal groups with tylosin and virginiamycin and in E. faecalis as well as in E. faecium strains with narasin and bacitracin. Resistance against ampicillin was mainly found among E. faecium strains from pets and was absent in E. faecalis. Tetracycline resistance occurred most often in strains from farm animals, while enrofloxacin resistance, only found in E. faecalis, occurred equally among strains from all origins. Resistance against gentamicin was very rare in broiler strains, whereas resistance rates were high in strains from other origins. It can be concluded that resistance against antibiotics used solely for growth promotion was more prevalent in E. faecium strains than in E. faecalis strains. With few exceptions, resistance against the different categories of antibiotics was more prevalent in strains from farm animals than in those from pets.

  12. Differences in Antibiotic Resistance Patterns of Enterococcus faecalis and Enterococcus faecium Strains Isolated from Farm and Pet Animals

    PubMed Central

    Butaye, Patrick; Devriese, Luc A.; Haesebrouck, Freddy

    2001-01-01

    The prevalence of acquired resistance in 146 Enterococcus faecium and 166 Enterococcus faecalis strains from farm and pet animals, isolated in 1998 and 1999 in Belgium, against antibiotics used for growth promotion and for therapy was determined. Acquired resistance against flavomycin and monensin, two antibiotics used solely for growth promotion, was not detected. Avoparcin (glycopeptide) resistance was found sporadically in E. faecium only. Avilamycin resistance was almost exclusively seen in strains from farm animals. Resistance rates were higher in E. faecium strains from broiler chickens than in strains from other animal groups with tylosin and virginiamycin and in E. faecalis as well as in E. faecium strains with narasin and bacitracin. Resistance against ampicillin was mainly found among E. faecium strains from pets and was absent in E. faecalis. Tetracycline resistance occurred most often in strains from farm animals, while enrofloxacin resistance, only found in E. faecalis, occurred equally among strains from all origins. Resistance against gentamicin was very rare in broiler strains, whereas resistance rates were high in strains from other origins. It can be concluded that resistance against antibiotics used solely for growth promotion was more prevalent in E. faecium strains than in E. faecalis strains. With few exceptions, resistance against the different categories of antibiotics was more prevalent in strains from farm animals than in those from pets. PMID:11302798

  13. Riboflavin-shuttled extracellular electron transfer from Enterococcus faecalis to electrodes in microbial fuel cells.

    PubMed

    Zhang, Enren; Cai, Yamin; Luo, Yue; Piao, Zhe

    2014-11-01

    Great attention has been focused on Gram-negative bacteria in the application of microbial fuel cells. In this study, the Gram-positive bacterium Enterococcus faecalis was employed in microbial fuel cells. Bacterial biofilms formed by E. faecalis ZER6 were investigated with respect to electricity production through the riboflavin-shuttled extracellular electron transfer. Trace riboflavin was shown to be essential for transferring electrons derived from the oxidation of glucose outside the peptidoglycan layer in the cell wall of E. faecalis biofilms formed on the surface of electrodes, in the absence of other potential electron mediators (e.g., yeast extract).

  14. Probiotic properties and adsorption of Enterococcus faecalis PSCT3-7 to vermiculite.

    PubMed

    Kim, Jin-Yoon; Awji, Elias Gebru; Park, Na-Hye; Park, Ji-Yong; Kim, Jong-Choon; Lee, Sam-Pin; Suh, Joo-Won; Park, Seung-Chun

    2017-03-30

    The probiotic properties of Enterococcus (E.) faecalis PSCT3-7, a new strain isolated from the intestines of pigs fed dietary fiber containing 50% sawdust, were investigated. E. faecalis PSCT3-7 tolerated a pH range of 3 to 8 and 0.3% bile salts, and it inhibited the growth of Salmonella Typhimurium in a concentration-dependent manner. In addition, E. faecalis showed resistance to several antibacterial agents. Vermiculite, a nutrient and microbial carrier, increased the bile tolerance of the strain. Scanning electron microscope images revealed good adsorption of E. faecalis PSCT3-7 onto vermiculite. E. faecalis PSCT3-7 represents a potential probiotic candidate to administer with vermiculite to swine.

  15. Probiotic properties and adsorption of Enterococcus faecalis PSCT3-7 to vermiculite

    PubMed Central

    Kim, Jin-Yoon; Awji, Elias Gebru; Park, Na-Hye; Park, Ji-Yong; Kim, Jong-Choon; Lee, Sam-Pin

    2017-01-01

    The probiotic properties of Enterococcus (E.) faecalis PSCT3-7, a new strain isolated from the intestines of pigs fed dietary fiber containing 50% sawdust, were investigated. E. faecalis PSCT3-7 tolerated a pH range of 3 to 8 and 0.3% bile salts, and it inhibited the growth of Salmonella Typhimurium in a concentration-dependent manner. In addition, E. faecalis showed resistance to several antibacterial agents. Vermiculite, a nutrient and microbial carrier, increased the bile tolerance of the strain. Scanning electron microscope images revealed good adsorption of E. faecalis PSCT3-7 onto vermiculite. E. faecalis PSCT3-7 represents a potential probiotic candidate to administer with vermiculite to swine. PMID:27456777

  16. Biofilm mediates Enterococcus faecalis adhesion, invasion and survival into bovine mammary epithelial cells.

    PubMed

    Elhadidy, M; Zahran, E

    2014-03-01

    We proposed in this study that during intramammary infection, biofilm formation may facilitate adherence and colonization of Enterococcus faecalis to mammary gland epithelium. This was established by comparing six different Ent. faecalis isolates with different biofilm-forming profiles for their adhesive, invasive and survival capabilities to bovine mammary epithelial cell line (MAC-T). Our results showed increased ability of the biofilm-producer Ent. faecalis strains to adhere, invade and survive inside MAC-T cells rather than nonbiofilm-producer strains. We showed that growth of bacteria in bovine milk significantly augmented the adherence and invasion of all tested strains, and this feature was abolished again when strains were subcultured in brain heart infusion broth. Moreover, growth in bovine milk significantly increased biofilm formation by all tested strains. These results indicated that biofilm formation by Ent. faecalis, especially after expressing milk-dependent induction, may have special relevance in the pathogenesis of Ent. faecalis mastitis during intramammary infection by enhancing bovine mammary epithelial adhesion and colonization. Results obtained from current work highlighted the role of biofilm in the pathogenesis of Enterococcus faecalis mastitis. Those biofilm-forming strains might be substantial as useful antigens in diagnostic assays and as future vaccine candidates to control Ent. faecalis mastitis. © 2013 The Society for Applied Microbiology.

  17. The opportunistic pathogen Enterococcus faecalis resists phagosome acidification and autophagy to promote intracellular survival in macrophages.

    PubMed

    Zou, Jun; Shankar, Nathan

    2016-06-01

    While many strains of Enterococcus faecalis have been reported to be capable of surviving within macrophages for extended periods, the exact mechanisms involved are largely unknown. In this study, we found that after phagocytosis by macrophages, enterococci-containing vacuoles resist acidification, and E. faecalis is resistant to low pH. Ultrastructural examination of the enterococci-containing vacuole by transmission electron microscopy revealed a single membrane envelope, with no evidence of the classical double-membraned autophagosomes. Western blot analysis further confirmed that E. faecalis could trigger inhibition of the production of LC3-II during infection. By employing cells transfected with RFP-LC3 plasmid and infected with GFP-labelled E. faecalis, we also observed that E. faecalis was not delivered into autophagosomes during macrophage infection. While these observations indicated no role for autophagy in elimination of intracellular E. faecalis, enhanced production of reactive oxygen species and nitric oxide were keys to this process. Stimulation of autophagy suppressed the intracellular survival of E. faecalis in macrophages in vitro and decreased the burden of E. faecalis in vivo. In summary, the results from this study offer new insights into the interaction of E. faecalis with host cells and may provide a new approach to treatment of enterococcal infections.

  18. Phenotypic and molecular antibiotic resistance profile of Enterococcus faecalis and Enterococcus faecium isolated from different traditional fermented foods.

    PubMed

    Sánchez Valenzuela, Antonio; Lavilla Lerma, Leyre; Benomar, Nabil; Gálvez, Antonio; Pérez Pulido, Rubén; Abriouel, Hikmate

    2013-02-01

    A collection of 55 enterococci (41 Enterococcus faecium and 14 E. faecalis strains) isolated from various traditional fermented foodstuffs of both animal and vegetable origins, and water was evaluated for resistance against 15 antibiotics. Lower incidence of resistance was observed with gentamicin, ampicillin, penicillin and teicoplanin. However, a high incidence of antibiotic resistance was detected for rifampicin (12 out of 14 of isolates), ciprofloxacin (9/14), and quinupristin/dalfopristin (8/14) in E. faecalis strains. Enterococcus faecium isolates were resistant to rifampicin (25/41), ciprofloxacin (23/41), erythromycin (18/41), levofloxacin (16/41), and nitrofurantoin (15/41). One Enterococcus faecalis and two E. faecium strains were resistant to vancomycin (MIC>16 μg/mL). Among 55 isolates, 27 (19 E. faecium and eight E. faecalis) were resistant to at least three antibiotics. High level of multidrug resistance to clinically important antibiotics was detected in E. faecalis strains (57% of E. faecalis versus 46% of E. faecium), which showed resistance to six to seven antibiotics, especially those isolated from foods of animal origin. So, it is necessary to re-evaluate the use of therapeutic antibiotics in stock farms at both regional and international levels due to the high number of multiple resistant (MR) bacteria. Fifty-six MR E. faecalis and E. faecium strains selected from this and previous studies (Valenzuela et al., 2008, 2010) were screened by polymerase chain reaction for antibiotic resistance genes, revealing the presence of tet(L), tet(M), ermB, cat, efrA, efrB, mphA, or msrA/B genes. The ABC Multidrug Efflux Pump EfrAB was detected in 96% of E. faecalis strains and also in 13% of E. faecium strains; this is the first report describing EfrAB in this enterococcal species. The efflux pump-associated msrA/B gene was detected in 66.66% of E. faecium strains, but not in E. faecalis strains.

  19. Multicenter clinical evaluation of VRESelect agar for identification of vancomycin-resistant Enterococcus faecalis and Enterococcus faecium.

    PubMed

    Anderson, Neil W; Buchan, Blake W; Young, Carol L; Newton, Duane W; Brenke, Connie; Lapsley, Linda; Granato, Paul A; Ledeboer, Nathan A

    2013-08-01

    A chromogenic medium for identification of vancomycin-resistant Enterococcus faecalis and Enterococcus faecium, VRESelect, was compared to bile esculin azide agar with 6 μg/ml vancomycin (BEAV) for the isolation of vancomycin-resistant enterococci (VRE) from stool specimens. At 24 to 28 h, VRESelect demonstrated 98.7% (confidence interval [CI], 96.1 to 99.7%) sensitivity and 99.0% (CI, 98.0 to 99.6%) specificity versus 85.1% (CI, 79.8 to 89.5%) and 90.1% (CI, 79.8 to 89.5%) sensitivity and specificity, respectively, for BEAV.

  20. A new chromogenic agar medium, chromID VRE, to screen for vancomycin-resistant Enterococcus faecium and Enterococcus faecalis.

    PubMed

    Ledeboer, Nathan A; Tibbetts, Robert J; Dunne, William M

    2007-12-01

    We compared the performance of a chromogenic agar medium chromID VRE (bioMérieux, Marcy-l'Etoile, France) designed to recover and identify vancomycin-resistant enterococci (VRE) from clinical specimens with bile esculin azide vancomycin (BEAV) agar. For this study, 120 stool specimens were plated on chromID VRE and BEAV and examined after 24 and 48 h. At 24 h, the sensitivity and specificity were as follows: BEAV, 90.2% and 73%, respectively; chromID VRE, 86.3% and 100.0%, respectively. Furthermore, we determined that the sensitivity and specificity of chromID VRE for Enterococcus faecium were 85.4% and 100%, respectively, and for Enterococcus faecalis, 90% and 100%, respectively. We conclude that chromID VRE provides an equivalent sensitivity for the recovery of VRE from stool specimens, with improved specificity, and the added advantage of providing differentiation between vancomycin-resistant E. faecium and E. faecalis.

  1. Effects of ionophores on Enterococcus faecalis and E. faecium growth in pure and mixed ruminal culture

    USDA-ARS?s Scientific Manuscript database

    Enterococcus faecalis and faecium are Gram-positive human pathogens that can live in the gastrointestinal tract of food animals. Vancomycin-resistant enterococci (VRE) are an increasing threat to humans as a nosocomial infection, as well as a reservoir of antibiotic resistance genes. Ionophores ar...

  2. An indigenous gut bacterium, Enterococcus faecalis (Lactobacillales: Enterococcaceae), increases seed consumption by Harpalus pensylvanicus (Coleoptera: Carabidae)

    USDA-ARS?s Scientific Manuscript database

    Harpalus pensylvanicus is a beneficial beetle contributing to insect control and seed predation in North American cropland. The bacterial endosymbiont Enterococcus faecalis is found in the intestinal tract of H. pensylvanicus and is thought to contribute to the digestion of the insect's seed diet. W...

  3. Complete Genome Sequence of Enterococcus faecalis Strain W11 Isolated from an Algal Food Product

    PubMed Central

    Takizawa, Noboru

    2016-01-01

    Here, we report the complete genome sequence of Enterococcus faecalis strain W11 isolated from an algal food product in Japan. This study should facilitate the identification of a novel mechanism of glycerol metabolic control in lactic acid bacteria. PMID:27688337

  4. Draft Genome Sequence of Enterococcus faecalis Strain UCD-PD3

    PubMed Central

    De Vries, Dana R.; Martin, Alexandra L.; Coil, David A.

    2016-01-01

    Here, we present the draft genome sequence of Enterococcus faecalis strain UCD-PD3. The assembly contains 2,861,314 bp in 73 contigs. This strain was isolated from a feral domestic cat (Felis catus) anal sac secretion sample, as part of a project on isolating and characterizing the microbes present in feline anal sacs. PMID:27979940

  5. Genetic variability of vancomycin-resistant Enterococcus faecium and Enterococcus faecalis isolates from humans, chickens, and pigs in Malaysia.

    PubMed

    Getachew, Yitbarek; Hassan, Latiffah; Zakaria, Zunita; Abdul Aziz, Saleha

    2013-08-01

    Vancomycin-resistant enterococci (VRE) have been reported to be present in humans, chickens, and pigs in Malaysia. In the present study, representative samples of VRE isolated from these populations were examined for similarities and differences by using the multilocus sequence typing (MLST) method. Housekeeping genes of Enterococcus faecium (n = 14) and Enterococcus faecalis (n = 11) isolates were sequenced and analyzed using the MLST databases eBURST and goeBURST. We found five sequence types (STs) of E. faecium and six STs of E. faecalis existing in Malaysia. Enterococcus faecium isolates belonging to ST203, ST17, ST55, ST79, and ST29 were identified, and E. faecium ST203 was the most common among humans. The MLST profiles of E. faecium from humans in this study were similar to the globally reported nosocomial-related strain lineage belonging to clonal complex 17 (CC17). Isolates from chickens and pigs have few similarities to those from humans, except for one isolate from a chicken, which was identified as ST203. E. faecalis isolates were more diverse and were identified as ST4, ST6, ST87, ST108, ST274, and ST244, which were grouped as specific to the three hosts. E. faecalis, belonging to the high-risk CC2 and CC87, were detected among isolates from humans. In conclusion, even though one isolate from a chicken was found clonal to that of humans, the MLST analysis of E. faecium and E. faecalis supports the findings of others who suggest VRE to be predominantly host specific and that clinically important strains are found mainly among humans. The infrequent detection of a human VRE clone in a chicken may in fact suggest a reverse transmission of VRE from humans to animals.

  6. Nonclinical and Clinical Enterococcus faecium Strains, but Not Enterococcus faecalis Strains, Have Distinct Structural and Functional Genomic Features

    PubMed Central

    Kim, Eun Bae

    2014-01-01

    Certain strains of Enterococcus faecium and Enterococcus faecalis contribute beneficially to animal health and food production, while others are associated with nosocomial infections. To determine whether there are structural and functional genomic features that are distinct between nonclinical (NC) and clinical (CL) strains of those species, we analyzed the genomes of 31 E. faecium and 38 E. faecalis strains. Hierarchical clustering of 7,017 orthologs found in the E. faecium pangenome revealed that NC strains clustered into two clades and are distinct from CL strains. NC E. faecium genomes are significantly smaller than CL genomes, and this difference was partly explained by significantly fewer mobile genetic elements (ME), virulence factors (VF), and antibiotic resistance (AR) genes. E. faecium ortholog comparisons identified 68 and 153 genes that are enriched for NC and CL strains, respectively. Proximity analysis showed that CL-enriched loci, and not NC-enriched loci, are more frequently colocalized on the genome with ME. In CL genomes, AR genes are also colocalized with ME, and VF are more frequently associated with CL-enriched loci. Genes in 23 functional groups are also differentially enriched between NC and CL E. faecium genomes. In contrast, differences were not observed between NC and CL E. faecalis genomes despite their having larger genomes than E. faecium. Our findings show that unlike E. faecalis, NC and CL E. faecium strains are equipped with distinct structural and functional genomic features indicative of adaptation to different environments. PMID:24141120

  7. Biological changes of Enterococcus faecalis in the viable but nonculturable state.

    PubMed

    E, J; Jiang, Y T; Yan, P F; Liang, J P

    2015-11-23

    Enterococcus faecalis may enter a viable but nonculturable (VBNC) state under adverse conditions. E. faecalis, the major bacterial species present in failed root canal treatments, is thought to survive after endodontic treatment by entering a VBNC state. In this study, we characterized the VBNC state of E. faecalis. We designed 3 different protocols to successfully induce the VBNC state. Approximately one-third of bacteria entered a VBNC state after 15-30 days, and all remained viable for at least 2 months. The morphology, glycometabolism, and adhesion capabilities of VBNC cells differed from those of E. faecalis during the exponential growth phase. Specifically, VBNC E. faecalis cells could not decompose lactose, D-mannitol, or D-sorbitol, although they were able to metabolize sucrose. Transmission electron microscopy showed that the morphology of the VBNC E. faecalis cells changed significantly; the cytoplasmic matrix was unevenly condensed and the overall morphology of the cells became irregular, but the cell membranes remained intact. Although the adhesion ability of the bacteria decreased, VBNC E. faecalis could still adhere to collagen fiber type I and tooth dentine. The persistence of this adhesion ability may be important in the virulence of VBNC E. faecalis.

  8. Prevalence of Enterococcus faecalis in saliva and filled root canals of teeth associated with apical periodontitis

    PubMed Central

    Wang, Qian-Qian; Zhang, Cheng-Fei; Chu, Chun-Hung; Zhu, Xiao-Fei

    2012-01-01

    To investigate the prevalence of Enterococcus faecalis in saliva and filled root canals of patients requiring endodontic retreatment for apical periodontitis. Patients with apical periodontitis who were referred for endodontic retreatment were examined. The type and quality of the restoration, symptoms, quality of obturation were recorded. During retreatment, an oral rinse sample and root canal sample were cultured using brain-heart infusion agar and bile esculinazide agar to select for E. faecalis. The 16S rRNA technique was used to identify E. faecalis. A total of 32 women and 22 men (mean age: 38 years; s.d.: 11 years) and 58 teeth were studied. The prevalence of E. faecalis was 19% in the saliva and 38% in the root canals. The odds that root canals harbored E. faecalis were increased if the saliva habored this bacterium (odds ratio=9.7; 95% confidence interval=1.8–51.6; P<0.05). Teeth with unsatisfactory root obturation had more cultivable bacterial species in root canals than teeth with satisfactory root obturation (P<0.05). E. faecalis is more common in root canals of teeth with apical periodontitis than in saliva. The prevalence of E. faecalis in root canals is associated with the presence of E. faecalis in saliva. PMID:22422085

  9. Transmission and genetic diversity of Enterococcus faecalis during hatch of broiler chicks.

    PubMed

    Olsen, Rikke Heidemann; Christensen, Henrik; Bisgaard, Magne

    2012-11-09

    The normal gastrointestinal flora of poultry includes Enterococcus faecalis. E. faecalis is also associated with first week mortality of chickens, but it is not clear whether this is due to vertical or horizontal transmission. Aims of the present study were to investigate transmission and genetic diversity of E. faecalis during hatching of broiler chicks. When hatching started, 15% of the chicks were colonized with E. faecalis. This colonization was interpreted as vertical transmission and was higher than previously reported. Transmission of E. faecalis from parents older than 42 weeks was five times greater than transmission of E. faecalis from younger parents. Seventy percent of broiler chicks were colonized with E. faecalis within 24 h after hatch started, which was interpreted as horizontal transmission. Twenty-one sequence types (STs) were demonstrated among 322 isolates of E. faecalis obtained from newly hatched chicks representing 11 different broiler parent flocks. Furthermore, three STs (ST59, ST82, ST174) made up 50.6% of the isolates, indicating that these STs have adapted successfully to the avian niche. All STs, except those novel to this study, have previously been associated with lesions in poultry, underlining the importance of controlling these particular STs.

  10. Efficacy of Atmospheric Pressure Plasma as an Antibacterial Agent Against Enterococcus Faecalis in Vitro

    NASA Astrophysics Data System (ADS)

    Cao, Yingguang; Yang, Ping; Lu, Xinpei; Xiong, Zilan; Ye, Tao; Xiong, Qing; Sun, Ziyong

    2011-02-01

    Enterococcus faecalis (E. faecalis) is a microorganism that can survive extreme challenges in obturated root canals. The aim of this study was to evaluate the efficacy of a non-thermal atmospheric pressure plasma plume against E. faecalis in vitro. A non-thermal atmospheric pressure plasma jet device which could generate a cold plasma plume carrying a peak current of 300 mA was used. The antibacterial efficacy of this device against E. faecalis and its biofilm under different conditions was detected. The antibacterial efficacy of the plasma against E. faecalis and Staphylococcus aureus (S. aureus) was also evaluated. After plasma treatment, the average diameter of inhibition zone on S. aureus and E. faecalis was 2.62±0.26 cm and 1.06±0.30 cm, respectively (P < 0.05). The diameter was increased with prolongation of the treatment duration. The diameters of inhibition zone of the sealed Petri dishes were larger than those of the uncovered Petri dishes. There was significant difference in colony-forming units between plasma group and control group on E. faecalis biofilm (P < 0.01). The transmission electron microscopy revealed that the ultrastructural changes cytoderm of E. faecalis were observed after treatment for 2 min. It is concluded that the non-thermal atmospheric pressure plasma could serve as an effective adjunct to standard endodontic microbial treatment.

  11. Prevalence of Enterococcus faecalis in saliva and filled root canals of teeth associated with apical periodontitis.

    PubMed

    Wang, Qian-Qian; Zhang, Cheng-Fei; Chu, Chun-Hung; Zhu, Xiao-Fei

    2012-03-01

    To investigate the prevalence of Enterococcus faecalis in saliva and filled root canals of patients requiring endodontic retreatment for apical periodontitis. Patients with apical periodontitis who were referred for endodontic retreatment were examined. The type and quality of the restoration, symptoms, quality of obturation were recorded. During retreatment, an oral rinse sample and root canal sample were cultured using brain-heart infusion agar and bile esculinazide agar to select for E. faecalis. The 16S rRNA technique was used to identify E. faecalis. A total of 32 women and 22 men (mean age: 38 years; s.d.: 11 years) and 58 teeth were studied. The prevalence of E. faecalis was 19% in the saliva and 38% in the root canals. The odds that root canals harbored E. faecalis were increased if the saliva habored this bacterium (odds ratio=9.7; 95% confidence interval=1.8-51.6; P<0.05). Teeth with unsatisfactory root obturation had more cultivable bacterial species in root canals than teeth with satisfactory root obturation (P<0.05). E. faecalis is more common in root canals of teeth with apical periodontitis than in saliva. The prevalence of E. faecalis in root canals is associated with the presence of E. faecalis in saliva.

  12. Longer Intestinal Persistence of Enterococcus faecalis Compared to Enterococcus faecium Clones in Intensive-Care-Unit Patients▿

    PubMed Central

    Ruiz-Garbajosa, Patricia; del Campo, Rosa; Coque, Teresa M.; Asensio, Angel; Bonten, Marc; Willems, Rob; Baquero, Fernando; Cantón, Rafael

    2009-01-01

    The dynamics of intestinal colonization with enterococcal clones in intensive-care-unit (ICU) patients was evaluated. Eight patients admitted directly to the neurosurgical ICU at the Ramón y Cajal University Hospital (Madrid, Spain) from the community and with no overlapping stay during a 10-month period in 2006 were studied. Rectal swab specimens were collected on admission and daily until the patients were discharged. Clonality was determined by pulsed-field gel electrophoresis and multilocus sequence typing. Clonal colonization dynamics were estimated by using two new parameters: the clonal diversity per patient per day (CDPD) and the clonal persistence ratio (CPR). Enterococcus faecalis isolates (n = 123) and Enterococcus faecium isolates (n = 66) were resolved into 13 and 15 clones, respectively. The CDPD of E. faecalis steadily increased during admission, and E. faecalis showed a higher (P = 0.001) CPR value than E. faecium (0.86 and 0.42, respectively). E. faecium, with the exception of an ampicillin-resistant clone belonging to clonal complex 17, frequently appeared as a short-term colonizer, even though the E. faecalis clones had significantly (P = 0.03) more days under antibiotic exposure than E. faecium (77.5 and 65 days/100 colonization days, respectively). E. faecalis had a longer persistence than E. faecium, except for the CC17 ampicillin-resistant clone, and E. faecalis showed a cumulative increase in CDPD, whereas E. faecium did not. CDPD and CPR were useful for measuring the dynamics of intestinal colonization with enterococcal clones. PMID:19052172

  13. Enterococcus Faecalis Biofilm. Formation and Development in Vitro Observed by Scanning Electron Microscopy.

    PubMed

    Bulacio, María de Los Á; Galván, Lucas R; Gaudioso, Cristina; Cangemi, Rosa; Erimbaue, Marta I

    2015-12-01

    Biofilm produced by Enterococcus faecalis isolated from root canals was detected by growing it on microplates and using 10% crystal violet stain, elution with alcohol and three procedures: no fixation, heat fixation and 10% formaldehyde fixation. The biofilm was evaluated using a Versamax Microplate Reader (USA). Twenty sterile root portions were incubated in TS broth with E. faecalis (108) for 48 hours, 4, 7, 14 and 30 days, after which they were processed and observed by scanning electron microscopy (SEM). Significantly more biofilm was found on the microplates for formaldehyde fixation than for heat fixation or no fixation (ANOVA p<0.0001). SEM showed E. faecalis growth at all times and biofilm development as from 14 days' incubation. Fixation with 10% formaldehyde was the most appropriate technique for detecting E. faecalis biofilm development on microplates. SEM confirmed biofilm formation after 14 days incubation.

  14. The surface rhamnopolysaccharide epa of Enterococcus faecalis is a key determinant of intestinal colonization.

    PubMed

    Rigottier-Gois, Lionel; Madec, Clément; Navickas, Albertas; Matos, Renata C; Akary-Lepage, Elodie; Mistou, Michel-Yves; Serror, Pascale

    2015-01-01

    Enterococcus faecalis is a commensal bacterium of the human intestine and a major opportunistic pathogen in immunocompromised and elderly patients. The pathogenesis of E. faecalis infection relies in part on its capacity to colonize the gut. Following disruption of intestinal homeostasis, E. faecalis can overgrow, cross the intestinal barrier, and enter the lymph and bloodstream. To identify and characterize E. faecalis genes that are key to intestinal colonization, our strategy consisted in screening mutants for the following phenotypes related to intestinal lifestyle: antibiotic resistance, overgrowth, and competition against microbiota. From the identified colonization genes, epaX encodes a glycosyltransferase located in a variable region of the enterococcal polysaccharide antigen (epa) locus. We demonstrated that EpaX acts on sugar composition, promoting resistance to bile salts and cell wall integrity. Given that EpaX is enriched in hospital-adapted isolates, this study points to the importance of the epa variability as a key determinant for enterococcal intestinal colonization.

  15. Ligand-Signaled Upregulation of Enterococcus faecalis ace Transcription, a Mechanism for Modulating Host-E. faecalis Interaction

    PubMed Central

    Nallapareddy, Sreedhar R.; Murray, Barbara E.

    2006-01-01

    Enterococcus faecalis, the third most frequent cause of bacterial endocarditis, appears to be equipped with diverse surface-associated proteins showing structural-fold similarity to the immunoglobulin-fold family of staphylococcal adhesins. Among the putative E. faecalis surface proteins, the previously characterized adhesin Ace, which shows specific binding to collagen and laminin, was detectable in surface protein preparations only after growth at 46°C, mirroring the finding that adherence was observed in 46°C, but not 37°C, grown E. faecalis cultures. To elucidate the influence of different growth and host parameters on ace expression, we investigated ace expression using E. faecalis OG1RF grown in routine laboratory media (brain heart infusion) and found that ace mRNA levels were low in all growth phases. However, quantitative reverse transcription-PCR showed 18-fold-higher ace mRNA amounts in cells grown in the presence of collagen type IV compared to the controls. Similarly, a marked increase was observed when cells were either grown in the presence of collagen type I or serum but not in the presence of fibrinogen or bovine serum albumin. The production of Ace after growth in the presence of collagen type IV was demonstrated by immunofluorescence microscopy, mirroring the increased ace mRNA levels. Furthermore, increased Ace expression correlated with increased collagen and laminin adhesion. Collagen-induced Ace expression was also seen in three of three other E. faecalis strains of diverse origins tested, and thus it appears to be a common phenomenon. The observation of host matrix signal-induced adherence of E. faecalis may have important implications on our understanding of this opportunistic pathogen. PMID:16926389

  16. Production of tyramine by Enterococcus faecalis strains in water-boiled salted duck.

    PubMed

    Liu, Fang; Du, Lihui; Xu, Weiyan; Wang, Daoying; Zhang, Muhan; Zhu, Yongzhi; Xu, Weimin

    2013-05-01

    The potential to produce biogenic amines was investigated with 15 Lactococcus lactis and 15 Enterococcus faecalis strains isolated from water-boiled salted duck. The production of biogenic amines from the isolated strains grown in de Man Rogosa Sharpe broth containing precursor amino acids was determined by thin-layer chromatography and high-performance liquid chromatography. None of the L. lactis strains produced any biogenic amines, whereas 12 strains of E. faecalis produced tyramine and b -phenylethylamine. PCR assays were used to detect the presence of tyrosine decarboxylase genes in all of the isolated strains. Only the 12 biogenic amine-producing Enterococcus strains had a 924-bp fragment characteristic for the tyrosine decarboxylase gene. The comparison of the amplified partial tyrDC gene sequences of the 12 positive Enterococcus strains revealed 99% similarity within the same species. The tyramine production of the sterilized water-boiled salted duck inoculated with E. faecalis R612Z1 increased significantly during storage. This study reveals that the isolated E. faecalis strains can produce tyramine and β-phenylethylamine in the medium; however, they can only produce tyramine in water-boiled salted duck.

  17. Antibacterial Potential of 2.5% Sodium Hypochlorite in Distinct Irrigation Protocols on Enterococcus faecalis Biofilm.

    PubMed

    Alves, Denise Ramos Silveira; Cunha, Rodrigo Sanches; da Silveira Bueno, Carlos Eduardo; de Alencar, Ana Helena Gonçalves; de Araújo Estrela, Cyntia Rodrigues; dos Santos, Tatiane Oliveira; Estrela, Carlos

    2015-05-01

    The aim of this study was to evaluate the effect of irrigation methods on antibacterial potential of 2.5% NaOCl on Enterococcus faecalis biofilm. Enterococcus faecalis biofilms were prepared during 60 days on 48 human root canals and randomized into control and experimental groups using positive and negative pressure irrigation. Bacterial growth was analyzed using turbidity of culture medium followed by UV spectrophotometry, and scanning electron microscopy (SEM) analyses were performed. Mean and standard deviations were used for evaluate the mean optical densities associated to the number of bacteria present culture, and Scheirer-Ray-Hare (an extension of the Kruskal-Wallis test) and Tamhane test to analyze the SEM images in the groups and thirds. Significance was set at 5%. Enterococcus faecalis was still present after root canal cleaning regardless of irrigation methods or bacterial identification methods. Positive and negative pressure irrigation protocols using 2.5% NaOCl show a similar capacity to reduce E. faecalis in infected root canals.

  18. New Insights into the Antimicrobial Effect of Mast Cells against Enterococcus faecalis

    PubMed Central

    Scheb-Wetzel, Matthias; Rohde, Manfred; Bravo, Alicia

    2014-01-01

    Enterococcus faecalis has emerged as an important cause of life-threatening multidrug-resistant bacterial infections in the hospital setting. The pathogenesis of enterococcal infections has remained a relatively neglected field despite their obvious clinical relevance. The objective of this study was to characterize the interactions between mast cells (MCs), an innate immune cell population abundant in the intestinal lamina propria, and E. faecalis. This study was conducted with primary bone marrow-derived murine MCs. The results demonstrated that MCs exerted an antimicrobial effect against E. faecalis that was mediated both by degranulation, with the concomitant discharge of the antimicrobial effectors contained in the granules, and by the release of extracellular traps, in which E. faecalis was snared and killed. In particular, the cathelicidin LL-37 released by the MCs had potent antimicrobial effect against E. faecalis. We also investigated the specific receptors involved in the recognition of E. faecalis by MCs. We found that Toll-like receptors (TLRs) are critically involved in the MC recognition of E. faecalis, since MCs deficient in the expression of MyD88, an adaptor molecule required for signaling by most TLRs, were significantly impaired in their capacity to degranulate, to reduce E. faecalis growth as well as to release tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6) after encountering this pathogen. Furthermore, TLR2 was identified as the most prominent TLR involved in the recognition of E. faecalis by MCs. The results of this study indicate that MCs may be important contributors to the host innate immune defenses against E. faecalis. PMID:25114115

  19. Enterococcus faecalis promotes innate immune suppression and polymicrobial catheter-associated urinary tract infection.

    PubMed

    Tien, Brenda Yin Qi; Goh, Hwee Mian Sharon; Chong, Kelvin Kian Long; Bhaduri-Tagore, Soumili; Holec, Sarah; Dress, Regine; Ginhoux, Florent; Ingersoll, Molly A; Williams, Rohan B H; Kline, Kimberly A

    2017-09-11

    Enterococcus faecalis, a member of the human gastrointestinal microbiota, is an opportunistic pathogen associated with hospital-acquired wound, bloodstream, and urinary tract infections. E. faecalis can subvert or evade immune-mediated clearance, although the mechanisms are poorly understood. In this study, we examined E. faecalis-mediated subversion of macrophage activation. We observed that E. faecalis actively prevents NF-κB signaling in mouse RAW264.7 macrophages in the presence of Toll-like receptor agonists and during polymicrobial infection with Escherichia coliE. faecalis and E. coli co-infection in a mouse model of catheter-associated urinary tract infection (CAUTI) resulted in a suppressed macrophage transcriptional response in the bladder compared to E. coli infection alone. Finally, we demonstrated that co-inoculation of E. faecalis with a commensal strain of E. coli into catheterized bladders significantly augmented E. coli CAUTI. Taken together, these results support that E. faecalis suppression of NF-κB-driven responses in macrophages promotes polymicrobial CAUTI pathogenesis especially when co-infected with less virulent or commensal E. coli strains. Copyright © 2017 American Society for Microbiology.

  20. Increased Enterococcus faecalis infection is associated with clinically active Crohn disease.

    PubMed

    Zhou, Youlian; Chen, Huiting; He, Hanchang; Du, Yanlei; Hu, Jiaqi; Li, Yingfei; Li, Yuyuan; Zhou, Yongjian; Wang, Hong; Chen, Ye; Nie, Yuqiang

    2016-09-01

    This study was performed to investigate the relationship between the abundance of pathogenic gut microbes in Chinese patients with inflammatory bowel disease (IBD) and disease severity.We collected clinical data and fecal samples from 47 therapy-naive Chinese patients with ulcerative colitis (UC), 67 patients with Crohn disease (CD), and 48 healthy volunteers. Bacteria levels of Fusobacterium species (spp), enterotoxigenic Bacteroides fragilis (B fragilis), enteropathogenic Escherichia coli (E coli), and Enterococcus faecalis (E faecalis) were assessed by quantitative real-time PCR (qRT-PCR). Spearman correlation coefficients were calculated to test associations between bacterial content and clinical parameters.Compared to healthy controls, the levels of both Fusobacterium spp and E faecalis were significantly increased in the feces of patients with IBD (P < 0.01). B fragilis levels were higher (P < 0.05) and E faecalis levels lower (P < 0.05) in patients with CD compared to those with UC. Increased E faecalis colonization in CD associated positively with disease activity (P = 0.015), Crohn disease activity index (CDAI; R = 0.3118, P = 0.0108), and fecal calprotectin (P = 0.016).E faecalis and Fusobacterium spp are significantly enriched in patients with IBD, and increased E faecalis infection is associated with clinically active CD.

  1. MurAA Is Required for Intrinsic Cephalosporin Resistance of Enterococcus faecalis

    PubMed Central

    Vesić, Dušanka

    2012-01-01

    Enterococcus faecalis is a low-GC Gram-positive bacterium that is intrinsically resistant to cephalosporins, antibiotics that target cell wall biosynthesis. To probe the mechanistic basis for intrinsic resistance, a library of transposon mutants was screened to identify E. faecalis strains that are highly susceptible to ceftriaxone, revealing a transposon mutant with a disruption in murAA. murAA is predicted to encode a UDP-N-acetylglucosamine 1-carboxyvinyl transferase that catalyzes the first committed step in peptidoglycan synthesis: phosphoenolpyruvate (PEP)-dependent conversion of UDP-N-acetylglucosamine to UDP-N-acetylglucosamine-enolpyruvate. In-frame deletion of murAA, but not its homolog in the E. faecalis genome (murAB), led to increased susceptibility of E. faecalis to cephalosporins. Furthermore, expression of murAA enhanced cephalosporin resistance in an E. faecalis mutant lacking IreK (formerly PrkC), a key kinase required for cephalosporin resistance. Further genetic analysis revealed that MurAA catalytic activity is necessary but not sufficient for this role. Collectively, our data indicate that MurAA and MurAB have distinct roles in E. faecalis physiology and suggest that MurAA possesses a unique property or activity that enables it to enhance intrinsic resistance of E. faecalis to cephalosporins. PMID:22290954

  2. Increased Enterococcus faecalis infection is associated with clinically active Crohn disease

    PubMed Central

    Zhou, Youlian; Chen, Huiting; He, Hanchang; Du, Yanlei; Hu, Jiaqi; Li, Yingfei; Li, Yuyuan; Zhou, Yongjian; Wang, Hong; Chen, Ye; Nie, Yuqiang

    2016-01-01

    Abstract This study was performed to investigate the relationship between the abundance of pathogenic gut microbes in Chinese patients with inflammatory bowel disease (IBD) and disease severity. We collected clinical data and fecal samples from 47 therapy-naive Chinese patients with ulcerative colitis (UC), 67 patients with Crohn disease (CD), and 48 healthy volunteers. Bacteria levels of Fusobacterium species (spp), enterotoxigenic Bacteroides fragilis (B fragilis), enteropathogenic Escherichia coli (E coli), and Enterococcus faecalis (E faecalis) were assessed by quantitative real-time PCR (qRT-PCR). Spearman correlation coefficients were calculated to test associations between bacterial content and clinical parameters. Compared to healthy controls, the levels of both Fusobacterium spp and E faecalis were significantly increased in the feces of patients with IBD (P < 0.01). B fragilis levels were higher (P < 0.05) and E faecalis levels lower (P < 0.05) in patients with CD compared to those with UC. Increased E faecalis colonization in CD associated positively with disease activity (P = 0.015), Crohn disease activity index (CDAI; R = 0.3118, P = 0.0108), and fecal calprotectin (P = 0.016). E faecalis and Fusobacterium spp are significantly enriched in patients with IBD, and increased E faecalis infection is associated with clinically active CD. PMID:27684872

  3. Prevalence and Genetic Diversity of Enterococcus faecalis Isolates from Mineral Water and Spring Water in China

    PubMed Central

    Wei, Lei; Wu, Qingping; Zhang, Jumei; Guo, Weipeng; Chen, Moutong; Xue, Liang; Wang, Juan; Ma, Lianying

    2017-01-01

    Enterococcus faecalis is an important opportunistic pathogen which is frequently detected in mineral water and spring water for human consumption and causes human urinary tract infections, endocarditis and neonatal sepsis. The aim of this study was to determine the prevalence, virulence genes, antimicrobial resistance and genetic diversity of E. faecalis from mineral water and spring water in China. Of 314 water samples collected from January 2013 to January 2014, 48 samples (15.3%) were contaminated E. faecalis. The highest contamination rate occurred in activated carbon filtered water of spring water (34.5%), followed by source water of spring water (32.3%) and source water of mineral water (6.4%). The virulence gene test of 58 E. faecalis isolates showed that the detection rates of asa1, ace, cylA, gelE and hyl were 79.3, 39.7, 0, 100, 0%, respectively. All 58 E. faecalis isolates were not resistant to 12 kinds of antibiotics (penicillin, ampicillin, linezolid, quinupristin/dalfopristin, vancomycin, gentamicin, streptomycin, ciprofloxacin, levofloxacin, norfloxacin, nitrofurantoin, and tetracycline). Enterobacterial repetitive intergenic consensus-PCR classified 58 isolates and three reference strains into nine clusters with a similarity of 75%. This study is the first to investigate the prevalence of E. faecalis in mineral water and spring water in China. The results of this study suggested that spring water could be potential vehicles for transmission of E. faecalis. PMID:28670302

  4. Enterococcus faecalis colonisation and endocarditis in five intensive care patients as late sequelae of selective decontamination.

    PubMed

    Sijpkens, Y W; Buurke, E J; Ulrich, C; van Asselt, G J

    1995-03-01

    To describe Enterococcus faecalis colonisation and endocarditis in 5 intensive care patients after treatment with selective decontamination (SDD). Intensive care unit (ICU) in a general hospital. The patients were admitted to the ICU because of adult respiratory distress syndrome, polytrauma (2 patients), abdominal aortic surgery and gastrointestinal surgery. Because these patients needed mechanical ventilation they received systemic cefotaxime and SDD (polymyxin E, amphotericin B and norfloxacin). Colonisation with E. faecalis was documented in all patients. Intravascular catheter-related infection with E. faecalis occurred in 4 patients. None of the patients received antibiotics active against, E. faecalis, because body temperature normalised after catheter removal. In the course of his ICU stay one patient died. Autopsy showed E. faecalis endocarditis. The other 4 patients recovered from their primary illness, but had to be readmitted after several months because of E. faecalis endocarditis. One of these patients died. One patient recovered of endocarditis, but one year later valve surgery was necessary. The other 2 patients needed acute valve replacement. The latter 3 patients survived. We observed 5 patients with E. faecalis endocarditis as a late and severe sequela of SDD during their ICU stay.

  5. Identification of Polyketide Inhibitors Targeting 3-Dehydroquinate Dehydratase in the Shikimate Pathway of Enterococcus faecalis

    PubMed Central

    Hernandez-Valladares, Maria; Go, Maybelle Kho; Tung, Alvin; Aguda, Adeleke H.; Robinson, Robert C.; Yew, Wen Shan

    2014-01-01

    Due to the emergence of resistance toward current antibiotics, there is a pressing need to develop the next generation of antibiotics as therapeutics against infectious and opportunistic diseases of microbial origins. The shikimate pathway is exclusive to microbes, plants and fungi, and hence is an attractive and logical target for development of antimicrobial therapeutics. The Gram-positive commensal microbe, Enterococcus faecalis, is a major human pathogen associated with nosocomial infections and resistance to vancomycin, the “drug of last resort”. Here, we report the identification of several polyketide-based inhibitors against the E. faecalis shikimate pathway enzyme, 3-dehydroquinate dehydratase (DHQase). In particular, marein, a flavonoid polyketide, both inhibited DHQase and retarded the growth of Enterococcus faecalis. The purification, crystallization and structural resolution of recombinant DHQase from E. faecalis (at 2.2 Å resolution) are also reported. This study provides a route in the development of polyketide-based antimicrobial inhibitors targeting the shikimate pathway of the human pathogen E. faecalis. PMID:25072253

  6. Genetic relationships among Enterococcus faecalis isolates from different sources as revealed by multilocus sequence typing.

    PubMed

    Chen, X; Song, Y Q; Xu, H Y; Menghe, B L G; Zhang, H P; Sun, Z H

    2015-08-01

    Enterococcus faecalis is part of the natural gut flora of humans and other mammals; some isolates are also used in food production. So, it is important to evaluate the genetic diversity and phylogenetic relationships among E. faecalis isolates from different sources. Multilocus sequence typing protocol was used to compare 39 E. faecalis isolates from Chinese traditional food products (including dairy products, acidic gruel) and 4 published E. faecalis isolates from other sources including human-derived isolates employing 5 housekeeping genes (groEL, clpX, recA, rpoB, and pepC). A total of 23 unique sequence types were identified, which were grouped into 5 clonal complexes and 10 singletons. The value of standardized index of association of the alleles (IA(S)=0.1465) and network structure indicated a high frequency of intraspecies recombination across these isolates. Enterococcus faecalis lineages also exhibited clearly source-clustered distributions. The isolates from dairy source were clustered together. However, the relationship between isolates from acidic gruel and one isolate from a human source was close. The MLST scheme presented in this study provides a sharable and continuously growing sequence database enabling global comparison of strains from different sources, and will further advance our understanding of the microbial ecology of this important species.

  7. High Frequency of Vancomycin-Resistant Enterococcus Faecalis in an Iranian Referral Children Medical Hospital

    PubMed Central

    POURAKBARI, Babak; AGHDAM, Mojtaba Kamali; MAHMOUDI, Shima; ASHTIANI, Mohammad Taghi Haghi; SABOUNI, Farah; MOVAHEDI, Zahra; ALYARI, Amir Esmael; SADEGHI, Reihane Hosseinpour; MAMISHI, Setareh

    2012-01-01

    ABSTRACT Background: Enterococci have emerged in recent years as important nosocomial pathogens. Although most enterococcal human infections are caused by Enterococcus faecalis, studies on vancomycin resistance are usually limited to Enterococcus faecium isolates and a little is known about E. faecalis. Therefore we undertook this study to obtain information about the prevalence of vancomycin -resistant E. faecalis (VREF) and genes responsible for resistance. Material and methods: Ninety-one E. faecalis isolates of different patients admitted at Children's Medical Center from August 2009 to June 2010 were included in this cross-sectional study. Antimicrobial testing was performed by Kirby-Bauer disk diffusion method according to Clinical Laboratories Standards Institute (CLSI). Results: Among all isolates, 15 (16%) were identified as VR E. faecalis. PCR analysis revealed that all VREF isolates were positive for the vanA gene. Conclusion: The present study reports the highest range of VREF in Iran. The increased frequency of VREF, as seen with rapid rise in the number of VanA isolates should be considered in infection control practices. PMID:23400108

  8. Evaluation of Enterococcus faecalis adhesion, penetration, and method to prevent the penetration of Enterococcus faecalis into root cementum: Confocal laser scanning microscope and scanning electron microscope analysis.

    PubMed

    Halkai, Rahul S; Hegde, Mithra N; Halkai, Kiran R

    2016-01-01

    To ascertain the role of Enterococcus faecalis in persistent infection and a possible method to prevent the penetration of E. faecalis into root cementum. One hundred and twenty human single-rooted extracted teeth divided into five groups. Group I (control): intact teeth, Group II: no apical treatment done, Group III divided into two subgroups. In Groups IIIa and IIIb, root apex treated with lactic acid of acidic and neutral pH, respectively. Group IV: apical root cementum exposed to lactic acid and roughened to mimic the apical resorption. Group V: apical treatment done same as Group IV and root-end filling done using mineral trioxide aggregate (MTA). Apical one-third of all samples immersed in E. faecalis broth for 8 weeks followed by bone morphogenetic protein and obturation and again immersed into broth for 8 weeks. Teeth split into two halves and observed under confocal laser scanning microscope and scanning electron microscope, organism identified by culture and polymerase chain reaction techniques. Adhesion and penetration was observed in Group IIIa and Group IV. Only adhesion in Group II and IIIB and no adhesion and penetration in Group I and V. Adhesion and penetration of E. faecalis into root cementum providing a long-term nidus for subsequent infection are the possible reason for persistent infection and root-end filling with MTA prevents the adhesion and penetration.

  9. Evaluation of Enterococcus faecalis adhesion, penetration, and method to prevent the penetration of Enterococcus faecalis into root cementum: Confocal laser scanning microscope and scanning electron microscope analysis

    PubMed Central

    Halkai, Rahul S.; Hegde, Mithra N.; Halkai, Kiran R.

    2016-01-01

    Aim: To ascertain the role of Enterococcus faecalis in persistent infection and a possible method to prevent the penetration of E. faecalis into root cementum. Methodology: One hundred and twenty human single-rooted extracted teeth divided into five groups. Group I (control): intact teeth, Group II: no apical treatment done, Group III divided into two subgroups. In Groups IIIa and IIIb, root apex treated with lactic acid of acidic and neutral pH, respectively. Group IV: apical root cementum exposed to lactic acid and roughened to mimic the apical resorption. Group V: apical treatment done same as Group IV and root-end filling done using mineral trioxide aggregate (MTA). Apical one-third of all samples immersed in E. faecalis broth for 8 weeks followed by bone morphogenetic protein and obturation and again immersed into broth for 8 weeks. Teeth split into two halves and observed under confocal laser scanning microscope and scanning electron microscope, organism identified by culture and polymerase chain reaction techniques. Results: Adhesion and penetration was observed in Group IIIa and Group IV. Only adhesion in Group II and IIIB and no adhesion and penetration in Group I and V. Conclusion: Adhesion and penetration of E. faecalis into root cementum providing a long-term nidus for subsequent infection are the possible reason for persistent infection and root-end filling with MTA prevents the adhesion and penetration. PMID:27994316

  10. Different extracts of Zingiber officinale decrease Enterococcus faecalis infection in Galleria mellonella.

    PubMed

    Maekawa, Lilian Eiko; Rossoni, Rodnei Dennis; Barbosa, Júnia Oliveira; Jorge, Antonio Olavo Cardoso; Junqueira, Juliana Campos; Valera, Marcia Carneiro

    2015-01-01

    Dried, fresh and glycolic extracts of Zingiber officinale were obtained to evaluate the action against G. mellonella survival assay against Enterococcus faecalis infection. Eighty larvae were divided into: 1) E. faecalis suspension (control); 2) E. faecalis + fresh extract of Z. officinale (FEO); 3) E. faecalis + dried extract of Z. officinale (DEO); 4) E. faecalis + glycolic extract of Z. officinale (GEO); 5) Phosphate buffered saline (PBS). For control group, a 5 μL inoculum of standardized suspension (107 cells/mL) of E. faecalis (ATCC 29212) was injected into the last left proleg of each larva. For the treatment groups, after E. faecalis inoculation, the extracts were also injected, but into the last right proleg. The larvae were stored at 37 °C and the number of dead larvae was recorded daily for 168 h (7 days) to analyze the survival curve. The larvae were considered dead when they did not show any movement after touching. E. faecalis infection led to the death of 85% of the larvae after 168 h. Notwithstanding, in treatment groups with association of extracts, there was an increase in the survival rates of 50% (GEO), 61% (FEO) and 66% (DEO) of the larvae. In all treatment groups, the larvae exhibited a survival increase with statistically significant difference in relation to control group (p=0.0029). There were no statistically significant differences among treatment groups with different extracts (p=0.3859). It may be concluded that the tested extracts showed antimicrobial activity against E. faecalis infection by increasing the survival of Galleria mellonella larvae.

  11. Brain abscess caused by Enterococcus faecalis following a dental procedure in a patient with hereditary hemorrhagic telangiectasia.

    PubMed

    Mylona, Eleni; Vadala, Chariklia; Papastamopoulos, Vasilios; Skoutelis, Athanasios

    2012-05-01

    Hereditary hemorrhagic telangiectasia (HHT) is a disease characterized by arteriovenous malformations (AVMs). Brain abscess is a complication of HHT with AVMs. Literature provides evidence that Enterococcus faecalis can cause endodontic infections. We present the case of an HHT patient who developed brain abscess due to E. faecalis after a dental procedure.

  12. Draft Genome Sequence of Enterococcus faecalis PC1.1, a Candidate Probiotic Strain Isolated from Human Feces

    PubMed Central

    Ó Cuív, Páraic; Klaassens, Eline S.; Smith, Wendy J.; Mondot, Stanislas; Durkin, A. Scott; Harkins, Derek M.; Foster, Les; McCorrison, Jamison; Torralba, Manolito; Nelson, Karen E.

    2013-01-01

    Enterococcus faecalis is commonly isolated from the gastrointestinal tract of healthy infants and adults, where it contributes to host health and well-being. We describe here the draft genome sequence of E. faecalis PC1.1, a candidate probiotic strain isolated from human feces. PMID:23469340

  13. Differences in the chemical composition of Enterococcus faecalis biofilm under conditions of starvation and alkalinity.

    PubMed

    Chen, Weixu; Liang, Jingping; He, Zhiyan; Jiang, Wei

    2017-01-02

    ABSTACT This study aimed to investigate the dynamic changes that occur in the chemical composition of an Enterococcus faecalis (E. faecalis) biofilm under conditions of starvation and in an alkaline environment and to explore the function of chemical composition changes in the resistance of the E. faecalis biofilm to an extreme environment. This study established an in vitro E. faecalis biofilm model under starvation and in an alkaline environment. During the formation of the biofilm, the pH value and nutritional condition of the culture medium were changed, and the changes in chemical composition were observed using biochemical measures. The results showed that, when the pH value of the culture medium was 11, the percentage of water-insoluble polysaccharides in the biofilm was significantly lower than under other conditions. In addition, the percentage of water-soluble polysaccharides in culture medium with pH values of 9 and 11 gradually decreased. The level of the water-soluble polysaccharides in each milligram of dry weight of biofilm at pH 11 increased compared to that under other conditions. The results from this study indicate that the chemical composition of E. faecalis biofilm changed in extreme environments. These changes served as a defensive mechanism for E. faecalis against environmental pressures.

  14. Recovery of Enterococcus faecalis in root canal lumen of patients with primary and secondary endodontic lesions.

    PubMed

    Pirani, Chiara; Bertacci, Angelica; Cavrini, Francesca; Foschi, Federico; Acquaviva, Giovanni Luca; Prati, Carlo; Sambri, Vittorio

    2008-04-01

    The presence of Enterococcus faecalis in root canal teeth affected by primary and secondary periapical lesions was studied using polymerase chain reaction (PCR) assays. The association between presence of E. faecalis with clinical signs of apical lesions was assessed to evaluate a possible relationship between clinical findings. Microbial samples were obtained from healthy patients affected by different periapical lesions, 79 teeth with primary periapical lesion and 23 with secondary periapical lesion. For each tooth, clinical symptoms and X-ray appearance were examined. E. faecalis was detected in 6 of 79 samples with primary lesion (7.6%), and in 9 of 23 with secondary lesion (39.1%). Suggested association was found between E. faecalis and secondary apical lesions. As regard specific signs and symptoms E. faecalis was more associated with asymptomatic lesions (all p<0.05) than with symptomatic apical lesions. The study confirms the high presence of E. faecalis in secondary apical lesions. However, its effective role in endodontic pathogenesis such as bone periapical lesions needs to be clarified.

  15. Synergy characterization for Enterococcus faecalis strains displaying moderately high-level gentamicin and streptomycin resistance.

    PubMed Central

    Bantar, C E; Micucci, M; Fernandez Canigia, L; Smayevsky, J; Bianchini, H M

    1993-01-01

    Synergy of 14 Enterococcus faecalis strains displaying moderately high-level aminoglycoside resistance (MICs, 500 and 256 to 1,000 micrograms/ml for gentamicin and streptomycin, respectively) was characterized by time-kill studies. All strains proved resistant to penicillin plus the respective aminoglycoside. Strains with moderately high-level aminoglycoside resistance should be considered to exhibit high-level resistance in severe infections. PMID:8349776

  16. First report of the multidrug resistance gene cfr in Enterococcus faecalis of animal origin.

    PubMed

    Liu, Yang; Wang, Yang; Wu, Congming; Shen, Zhangqi; Schwarz, Stefan; Du, Xiang-Dang; Dai, Lei; Zhang, Wanjiang; Zhang, Qijing; Shen, Jianzhong

    2012-03-01

    The multiresistance gene cfr was identified for the first time in an Enterococcus faecalis isolate of animal origin. The 32,388-bp plasmid pEF-01, which carried the cfr gene, was sequenced completely. Three copies of the insertion sequence IS1216 were identified in pEF-01, and the detection of a cfr- and IS1216-containing amplicon by inverse PCR suggests that IS1216 may play a role in the dissemination of cfr by a recombination process.

  17. Deactivation of Enterococcus Faecalis Bacteria by an Atmospheric Cold Plasma Brush

    NASA Astrophysics Data System (ADS)

    Chen, Wei; Huang, Jun; Du, Ning; Liu, Xiao-Di; Lv, Guo-Hua; Wang, Xing-Quan; Zhang, Guo-Ping; Guo, Li-Hong; Yang, Si-Ze

    2012-07-01

    An atmospheric cold plasma brush suitable for large area and low-temperature plasma-based sterilization is designed and used to treat enterococcus faecalis bacteria. The results show that the efficiency of the inactivation process by helium plasma is dependent on applied power and exposure time. After plasma treatments, the cell structure and morphology changes can be observed by scanning electron microscopy. Optical emission measurements indicate that reactive species such as O and OH play a significant role in the sterilization process.

  18. [Antimicrobial susceptibility of Enterococcus faecalis isolated from patients in Córdoba (Spain)].

    PubMed

    Causse, M; Franco-Alvarez de Luna, F; García-Mayorgas, A D; Rodríguez, F C; Casal, M

    2006-06-01

    Enterococcus faecalis is a pathogenic microorganism. The aim of this investigation was to study the antibiotic susceptibility of the strains isolated in Cordoba in a 20-month period (January 2004 to August 2005). Susceptibility rates to betalactamics were 98% to ampicillin and 99% to amoxicillin/clavulanic acid; high-dose aminoglycosides (streptomycin 1000 microg and gentamycin 500 microg) obtained 56% and 76%, respectively. We found no strains resistant to glycopeptides (vancomycin and teicoplanin) or to linezolid.

  19. A rare case of Enterococcus faecalis-induced orbital cellulitis and myositis

    PubMed Central

    Kohli, Piyush; Ichhpujani, Parul; Bansal, Rakesh Kumar; Kumar, Suresh

    2016-01-01

    Orbital cellulitis is an infection of soft tissue behind the orbital septum. Common pathogens isolated include Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus pneumoniae. It is a straightforward diagnosis and usually responds to empirical treatment without any sequela. We report a case of orbital cellulitis caused by Enterococcus faecalis, which was complicated by myositis of levator palpebrae superioris. To the best of our knowledge, only one case report exists dating way back to 1986. PMID:27688288

  20. Alkaline stress response in Enterococcus faecalis: adaptation, cross-protection, and changes in protein synthesis.

    PubMed Central

    Flahaut, S; Hartke, A; Giard, J C; Auffray, Y

    1997-01-01

    The alkaline shock response in Enterococcus faecalis was studied in this work. Cells adapted to an optimum pH of 10.5 were tolerate to pH 11.9 conditions but acquired sensitivity to acid damage. An analysis of stress proteins revealed that 37 polypeptides were amplified. Two of these are DnaK and GroEL. The combined results show that bile salts and alkaline stress responses are closely related. PMID:9023964

  1. Relationship between biofilm formation, the enterococcal surface protein (Esp) and gelatinase in clinical isolates of Enterococcus faecalis and Enterococcus faecium.

    PubMed

    Di Rosa, Roberta; Creti, Roberta; Venditti, Mario; D'Amelio, Raffaele; Arciola, Carla R; Montanaro, Lucio; Baldassarri, Lucilla

    2006-03-01

    One-hundred and twenty-eight enterococcal isolates were examined for their ability to form biofilm in relation to the presence of the gene encoding the enterococcal surface protein (esp), production of gelatinase and to the source of isolation. Neither esp nor gelatinase seemed to be required for biofilm formation: both Enterococcus faecalis and Enterococcus faecium did not show a correlation between the presence of either esp or the production of gelatinase and biofilm formation. However, in E. faecium while esp was found in isolates from either source, the presence of both esp and biofilm together was only found in strains from clinical settings, suggesting that there exists a synergy between these factors which serves as an advantage for the process of infection.

  2. Prevalence and characterization of antibiotic resistant Enterococcus faecalis in French cheeses.

    PubMed

    Jamet, Emmanuel; Akary, Elodie; Poisson, Marie-Ange; Chamba, Jean-François; Bertrand, Xavier; Serror, Pascale

    2012-09-01

    Prevalence of enterococci and antibiotic resistance profiles of Enterococcus faecalis was analyzed in 126 French cheeses from retail stores. Forty-four percent of pasteurized or thermised-milk cheeses, and up to 92% of raw-milk cheeses contained detectable enterococci. A total of 337 antibiotic resistant enterococci were isolated in 29% and 60% of pasteurized-milk and raw-milk cheeses, respectively. E. faecalis was the predominant antibiotic resistant species recovered (81%), followed by Enterococcus faecium (13%), and Enterococcus durans (6%). The most prevalent antibiotic resistances were tetracycline (Tet) and minocycline (Min), followed by erythromycin (Ery), kanamycin (Kan) and chloramphenicol (Cm). The most common multiple antibiotic resistance phenotype was Cm Ery Kan Min Tet. The occurrence of antibiotic genes, as searched by PCR, was 100 % for aph3'IIIa, 96 % for ermB, 90 % for tetM and 80 % for catA in isolates resistant to Kan, Ery, Tet or Cm, respectively. MLST analysis of 30 multidrug resistant E. faecalis revealed that ST19, CC21, CC25 and CC55 isolates were the most common in cheeses. In conclusion, as in many other European countries, French cheeses do contain enterococci with multiple antibiotics resistances. However, low occurrence of high-level gentamicin resistant or sulfamethoxazole/trimethoprim-resistant enterococci and absence of vancomycin- or ampicillin- resistant enterococci indicate that cheeses cannot be considered as a major reservoir for nosocomial multi-drug resistant enterococci. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. In vitro antibacterial effect of different irrigating solutions on Enterococcus faecalis.

    PubMed

    Bulacio, María de los Angeles; Cangemi, Rosa; Cecilia, Marta; Raiden, Guillermo

    2006-01-01

    Was evaluated the minimum inhibitory concentration (MIC) and the antibacterial effect (AE) of 2.5% NaOCl, 0.2% chlorhexidine gluconate (CHX) and 17% EDTA on Enterococcus faecalis. The antibacterial capacity was assessed by difusion in agar. The AE was evaluated on contaminated root dentin, employing apical and middle portions of human roots, sterilized and contaminated with Enterococcus faecalis, immersed in the irrigation solutions and incubated at 37 degrees C. Viable cells were counted at 0, 4, 8 and 24 hours. MIC: NaOCl and CHX: 0.2%, EDTA below 5%. Diffusion in agar: NaOCl 2.5% = 21 mm. CHX 0.2% = 14 mm. EDTA 17% = 20 mm. Effect on root dentin: NaOCl 2.5%: Enterococcus faecalis was totally inhibited for 24 hours in the apical area, and for 8 hours in the middle area. CHX 0.2% elicited a reduction of more than 5 log CFU and EDTA 17% induced a reduction of more than 3 log CFU at all the time points examined in the apical and middle areas.

  4. Effect of NaCl Treatments on Tyramine Biosynthesis of Enterococcus faecalis.

    PubMed

    Liu, Fang; Wang, Xinxin; Du, Lihui; Wang, Daoying; Zhu, Yongzhi; Geng, Zhiming; Xu, Xiaoxi; Xu, Weimin

    2015-05-01

    The effect of NaCl stress (0 to 8%, wt/vol) on the growth and tyramine production in two Enterococcus faecalis strains was examined during culture time. The growth of E. faecalis was inhibited by the increase in NaCl concentration, but tyramine production was unaffected. Tyramine accumulated rapidly during the logarithmic phase of the strains, and the final tyramine levels were approximately 800 μg/ml. Relative gene expression of four genes in the tyrosine decarboxylase locus, namely, tyrRS, tyrDC, tyrP, and nhaC, was evaluated at different incubation times. The results showed that NaCl stress could upregulate the expression of tyrDC and tyrP to improve the tyramine production of a single E. faecalis strain under certain conditions, and TyrS could act as a negative regulator on the genetic regulation of the tyramine cluster.

  5. Bactericidal Effects of Diode Laser Irradiation on Enterococcus faecalis Using Periapical Lesion Defect Model

    PubMed Central

    Nagayoshi, Masato; Nishihara, Tatsuji; Nakashima, Keisuke; Iwaki, Shigetsugu; Chen, Ker-Kong; Terashita, Masamichi; Kitamura, Chiaki

    2011-01-01

    Objective. Photodynamic therapy has been expanded for use in endodontic treatment. The aim of this study was to investigate the antimicrobial effects of diode laser irradiation on endodontic pathogens in periapical lesions using an in vitro apical lesion model. Study Design. Enterococcus faecalis in 0.5% semisolid agar with a photosensitizer was injected into apical lesion area of in vitro apical lesion model. The direct effects of irradiation with a diode laser as well as heat produced by irradiation on the viability of microorganisms in the lesions were analyzed. Results. The viability of E. faecalis was significantly reduced by the combination of a photosensitizer and laser irradiation. The temperature caused by irradiation rose, however, there were no cytotoxic effects of heat on the viability of E. faecalis. Conclusion. Our results suggest that utilization of a diode laser in combination with a photosensitizer may be useful for clinical treatment of periapical lesions. PMID:21991489

  6. Antimicrobial activity of essential oils and chloroform alone and combinated with cetrimide against Enterococcus faecalis biofilm

    PubMed Central

    Ferrer Luque, Carmen Maria; González-Rodríguez, Maria Paloma; Arias-Moliz, Maria Teresa; Baca, Pilar

    2013-01-01

    Abstract The Enterococcus faecalis bacteria have been identified as the most commonly recovered species from teeth with persistent endodontic infections. The antimicrobial activity of essential oils and chloroform (CHL), alone and in association with various concentrations of cetrimide (CTR), against biofilm of Enterococcus faecalis was investigated. Solutions of CHL, eucalyptus oil (EO) and orange oil (OO) associated with CTR at 0.3%, 0.2%, 0.1%, and 0.05% were used to determine antimicrobial activity by exposing treated bovine dentine blocks to E. faecalis. Biofilms grown in the dentine blocks for 7 days were exposed to solutions for 2 and 5 min. Biofilm reduction between OO and EO at 2 min did not show any significant differences; however, OO had a higher kill percentage of biofilms than did the eucalyptus oil at 5 min (p < 0.01). Combinations with CTR at all concentrations achieved a 100% kill rate at 2 and 5 min. The association of CTR with solvent agents achieved the maximum antimicrobial activity against E. faecalis biofilms in dentine. PMID:24265917

  7. Antibacterial Activity of Leaf Extract of Annona muricata and Simarouba glauca on Enterococcus faecalis.

    PubMed

    Mathew, Jain; George, Reshmi; Theruvil, Robin; Padavil, Tobin C; Tomy, Lincy; Kurian, Anil

    2016-08-01

    To determine the antimicrobial effect of water extracts of leaves of Annona muricata and Simarouba glauca on Enterococcus faecalis using agar diffusion method. Dried leaves of A. muricata and S. glauca were powdered and extracted in a soxhlet apparatus. Enterococcus faecalis was grown overnight in Trypticase soy agar plates. About 10 μl of each extract was placed on agar plates and incubated overnight. The zone of inhibition was measured after 24 hours. About 1% sodium hypochlorite and distilled water were used as positive and negative controls. The leaf extract of A. muricata showed similar effectiveness as that of sodium hypochlorite, whereas the leaf extract of S. glauca showed only a slight reduction in growth of E. faecalis. Leaf extract of A. muricata can be developed as an alternative to sodium hypochlorite for root canal irrigants. Success of endodontic treatment depends on complete disinfection of the root canals. Root canal irrigants have a major role in complete disinfection of the root canals. Chemical root canal irrigants are more or less toxic to the oral environment. In this study, naturally derived leaf extracts of A. muricata and S. glauca are compared with sodium hypochlorite for its effectiveness against E. faecalis - the most common pathogen found in the root canals.

  8. Investigation of mechanism and molecular epidemiology of linezolid-resistant Enterococcus faecalis in China.

    PubMed

    Wang, Lipeng; He, Yunyan; Xia, Yun; Wang, Huijuan; Liang, Shumei

    2014-08-01

    Enterococcus is a major cause of important nosocomial infections. Linezolid, the first member of an entirely new class of antibiotics (oxazolidinones), is effective against serious infections caused by Enterococcus. However, resistance to linezolid has been discovered throughout the world rapidly. From 2011 to 2013, nine linezolid-resistant E. faecalis isolates were collected and the possible mechanisms of linezolid resistance, including mutations in domain V of 23S rRNA genes and in ribosomal proteins L3 and L4, and the multiresistance gene cfr, were investigated. Furthermore, an epidemiological survey of the nine linezolid-resistant E. faecalis isolates was performed by pulsed field gel electrophoresis (PFGE), multilocus sequence typing (MLST) and DiversiLab. The three methods were compared to evaluate their merits and demerits, respectively. We failed to find the resistance mechanisms that have been revealed in recent years by PCR and sequencing analysis in the linezolid-resistant E. faecalis. Epidemiological investigation suggested that a small-scale outbreak of linezolid-resistant E. faecalis emerged in neurosurgery ICU from March to May of 2013. DiversiLab was a reliable typing tool and a suitable alternative to PFGE because it was as discriminatory as PFGE and better than MLST.

  9. Antibacterial Effect of All-in-one Self-etch Adhesives on Enterococcus faecalis

    PubMed Central

    Ebrahimi Chaharom, Mohammad Esmaeel; Ajami, Amir Ahmad; Abed Kahnamouei, Mehdi; Jafari Navimipour, Elmira; Tehranchi, Pardis; Zand, Vahid; Sadeghi, Mohammad Reza; Sohrabi, Aydin

    2014-01-01

    Background and aims. The aim of this study was to evaluate the antibacterial activity of one-step self-etch adhesives on Enterococcus faecalis on days 1, 7 and 14 with the use of modified direct contact test. Materials and methods. The modified directcontact test was used to evaluate the antibacterial effect of Adper Easy One, Bond Force, Clearfil S3 Bond, Futurabond M, G-Bond, iBond and OptiBond All-in-one adhesives on Enterococcus faecalis after aging the samples in phosphate-buffered saline for one, seven and fourteen days. Data were analyzed using one-way ANOVA and post hoc Tukey tests. Aging effect of each adhesive was evaluated by paired-sample test. In this study, P<0.05 was considered significant. Results. All the tested adhesives exhibited antibacterial activity after one day and had significant differences with the positive control group (P<0.05). After one week, OptiBond All-in-one, iBond and Futurabond M exhibited significant differences in bacterial growth from other groups (P<0.05). There were no significant differences between the groups in two weeks (P>0.05). Conclusion. iBond exhibited the highest antibacterial effect on E. faecalis after one week. Futurabond and OptiBond All-in-one exhibited antibacterial effects against E. faecalis for one week. PMID:25587384

  10. EFFICACY OF SODIUM HYPOCHLORITE AND CHLORHEXIDINE AGAINST Enterococcus faecalis – A SYSTEMATIC REVIEW

    PubMed Central

    Estrela, Carlos; Silva, Julio Almeida; de Alencar, Ana Helena Gonçalves; Leles, Claudio Rodrigues; Decurcio, Daniel Almeida

    2008-01-01

    The efficacy of the sodium hypochlorite (NaOCl) and chlorhexidine (CHX) on Enterococcus faecalis was evaluated by systematic review and meta-analysis. The search strategies included search in electronic biomedical journal databases (MEDLINE, EMBASE, CENTRAL) and handsearching records, using different matches of keywords for NaOCl, CHX and Enterococcus faecalis. From 41 in vivo studies, 5 studies met the inclusion criteria. In a sample containing 159 teeth, E. faecalis was detected initially in 16 (10%) teeth by polymerase chain reaction (PCR) and 42 (26.4%) teeth by microbial culture techniques. After root canal disinfection, this species was observed in 11 (6.9%) teeth by PCR and 12 (7.5%) teeth by culture. Risk differences of included studies were combined as generic inverse variance data type (Review Manager Version 5.0 – Cochrane Collaboration, http://www.cc-ims.net, accessed 15 May 2008), taking into account the separate tracking of positive and negative cultures/PCR. The level of statistical significance was set at p<0.05. In conclusion, NaOCl or CHX showed low ability to eliminate E. faecalis when evaluated by either PCR or culture techniques. PMID:19082392

  11. Ex vivo antimicrobial efficacy of strong acid electrolytic water against Enterococcus faecalis biofilm.

    PubMed

    Chen, X; Li, P; Wang, X; Gu, M; Zhao, C; Sloan, A J; Lv, H; Yu, Q

    2013-10-01

    To observe the antimicrobial effect of strong acid electrolytic water (SAEW) against an Enterococcus faecalis (E. faecalis) biofilm when used as a root canal irrigant. The effect of SAEW, sodium hypochlorite (5.25%; NaOCl) and sodium chloride (0.9%; normal saline) on E. faecalis biofilm vitality on coverslips was observed by confocal laser scanning microscopy (CLSM). Thirty-five root canals from extracted human teeth were sterilized prior to contamination with E. faecalis for four weeks. Bacterial samples were collected with sterile paper points and plated onto BHI agar plates for 48 h. Root canal walls were observed by scanning electron microscopy before and after instrumentation, together with root canal irrigation with SAEW, NaOCl or normal saline, with or without ultrasonic vibration. Antimicrobial effectiveness was established by counting colony-forming units and analysed by two-way anova. Confocal laser scanning microscopy revealed that SAEW decreased E. faecalis biofilm vitality, and the proportion of dead bacteria increased in accordance with increasing treatment time. Most bacteria in the biofilms were killed after 10-min treatment. No significant difference was observed between SAEW and NaOCl groups at the same treatment time (P > 0.05) or in the susceptibility of E. faecalis to SAEW and NaOCl (P > 0.05) in extracted human teeth with or without ultrasonic activation. SAEW and NaOCl were more effective against E. faecalis biofilm than normal saline, and antimicrobial efficacy was significantly enhanced by ultrasonic vibration (P < 0.05). Strong acid electrolytic water effectively killed E. faecalis in a biofilm both on coverslips and in the root canals of extracted human teeth. © 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  12. Ampicillin in Combination with Ceftaroline, Cefepime, or Ceftriaxone Demonstrates Equivalent Activities in a High-Inoculum Enterococcus faecalis Infection Model.

    PubMed

    Luther, Megan K; Rice, Louis B; LaPlante, Kerry L

    2016-05-01

    Ampicillin-ceftriaxone combination therapy has become a predominant treatment for serious Enterococcus faecalis infections, such as endocarditis. Unfortunately, ceftriaxone use is associated with future vancomycin-resistant enterococcus colonization. We evaluated E. faecalis in an in vitro pharmacodynamic model against simulated human concentration-time profiles of ampicillin plus ceftaroline, cefepime, ceftriaxone, or gentamicin. Ampicillin-cefepime and ampicillin-ceftaroline demonstrated activities similar to those of ampicillin-ceftriaxone against E. faecalis. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  13. Proteolytic activity of Enterococcus faecalis VB63F for reduction of allergenicity of bovine milk proteins.

    PubMed

    Biscola, V; Tulini, F L; Choiset, Y; Rabesona, H; Ivanova, I; Chobert, J-M; Todorov, S D; Haertlé, T; Franco, B D G M

    2016-07-01

    With the aim of screening proteolytic strains of lactic acid bacteria to evaluate their potential for the reduction of allergenicity of the major bovine milk proteins, we isolated a new proteolytic strain of Enterococcus faecalis (Ent. faecalis VB63F) from raw bovine milk. The proteases produced by this strain had strong activity against caseins (αS1-, αS2-, and β-casein), in both skim milk and sodium caseinate. However, only partial hydrolysis of whey proteins was observed. Proteolysis of Na-caseinate and whey proteins, observed after sodium dodecyl sulfate-PAGE, was confirmed by analysis of peptide profiles by reversed-phase HPLC. Inhibition of proteolysis with EDTA indicated that the proteases produced by Ent. faecalis VB63F belonged to the group of metalloproteases. The optimal conditions for their activity were 42°C and pH 6.5. The majority of assessed virulence genes were absent in Ent. faecalis VB63F. The obtained results suggest that Ent. faecalis VB63F could be efficient in reducing the immunoreactivity of bovine milk proteins.

  14. Genetic diversity of Enterococcus faecalis isolated from environmental, animal and clinical sources in Malaysia.

    PubMed

    Daniel, Diane S; Lee, Sui M; Gan, Han M; Dykes, Gary A; Rahman, Sadequr

    Enterococcus faecalis ranks as one of the leading causes of nosocomial infections. A strong epidemiological link has been reported between E. faecalis inhabiting animals and environmental sources. This study investigates the genetic diversity, antibiotic resistance and virulence determinants in E. faecalis from three sources in Malaysia. A total of 250 E. faecalis isolates were obtained consisting of 120 isolates from farm animals, 100 isolates from water sources and 30 isolates from hospitalized patients. Pulse-field gel electrophoresis-typing yielded 63 pulsotypes, with high diversity observed in all sources (D=≥0.901). No pulsotype was common to all the three sources. Each patient room had its own unique PFGE pattern which persisted after six months. Minimum inhibitory concentrations of Vancomycin, Gentamicin, Penicillin, Tetracycline, Nitrofurantoin, Levofloxacin, Ciprofloxacin and Fosfomycin were evaluated. Resistance to Tetracycline was most prevalent in isolates from farm animals (62%) and water sources (49%). Water isolates (86%) had a higher prevalence of the asa1 gene, which encodes for aggregation substance, whereas clinical (78%) and farm animal isolates (87%) had a higher prevalence of the esp gene, encoding a surface exposed protein. This study generates knowledge on the genetic diversity of E. faecalis with antibiotic resistance and virulence characteristics from various sources in Malaysia. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. Confocal microscopy evaluation of the effect of irrigants on Enterococcus faecalis biofilm: An in vitro study.

    PubMed

    Flach, Nicole; Böttcher, Daiana Elisabeth; Parolo, Clarissa Cavalcanti Fatturi; Firmino, Luciana Bitello; Malt, Marisa; Lammers, Marcelo Lazzaron; Grecca, Fabiana Soares

    2016-01-01

    The purpose of this study was to evaluate in vitro the effectiveness of two endodontic irrigants and their association against Enterococcus faecalis (E. faecalis) by confocal laser scanning microscope (CLSM). Twenty-four bovine incisors were inoculated in a monoculture of E. faecalis for 21 days. After this period, the teeth were divided into three test groups (n = 5) according to the chemical used. Group 1: 2.5% sodium hypochlorite (NaOCl), group 2: 2% chlorhexidine gel (CHX), group 3: 2.5% NaOCl + 2% CHX gel, and two control groups (n = 3): negative control group (NCG)-sterile and without root canals preparation and positive control group (PCG)-saline. Then, the samples were stained with SYTO9 and propidium iodide and subjected to analysis by CLSM. Bacterial viability was quantitatively analyzed by the proportions of dead and live bacteria in the biofilm remnants. Statistical analysis was performed by the One-way ANOVA test (p = 0.05). No statistical differences were observed to bacterial viability. According to CLSM analysis, none of the tested substances could completely eliminate E. faecalis from the root canal space. Until now, there are no irrigant solutions able to completely eliminate E. faecalis from the root canal. In this regard, the search for irrigants able to intensify the antimicrobial action is of paramount importance.

  16. Detection of the macrolide-efflux protein A gene mef(A) in Enterococcus faecalis.

    PubMed

    Schwaiger, Karin; Hölzel, Christina; Bauer, Johann

    2011-09-01

    The mef(A) gene codes for an efflux protein that conveys resistance to 14- and 15-membered macrolides. Enterococci are emerging pathogens, as well as indicator and reservoir bacteria that are known to have a strong tendency to acquire resistance genes. A total of 485 Enterococcus faecalis strains of porcine (n = 239) and human origin (n = 246) were screened for the presence of the mef(A) gene by using polymerase chain reaction. In total, 29 E. faecalis of porcine (n = 10) and human (n = 19) origin were positive for the presence of the mef(A) gene. Most of the mef(A)-containing strains were isolated from fecal samples of healthy individuals; only one strain originated from a stool sample of a diseased pig. To our knowledge, this is the first report on the occurrence of the mef(A) gene in E. faecalis apart from mating experiments. The main clinical relevance of this study is that donor E. faecalis might transfer the mef(A) gene to recipients that are usually combated with macrolides. Hence, the role of E. faecalis as a resistance reservoir with respect to limited treatment options are a cause for concern.

  17. Screening of Bacteriocin-producing Enterococcus faecalis Strains for Antagonistic Activities against Clostridium perfringens

    PubMed Central

    Kim, So-Young

    2014-01-01

    This study was conducted to isolate and characterize bacteriocin-producing bacteria against Clostridium perfringens (C. perfringens) from domestic animals to determine their usefulness as probiotics. Bacteriocin-producing bacteria were isolated from pig feces by the spot-on-lawn method. A total of 1,370 bacterial stains were isolated, and six were tentatively selected after identifying the inhibitory activity against the pathogenic indicator C. perfringens KCTC 3269 and KCTC 5100. The selected strains were identified as Enterococcus faecalis (E. faecalis) by 16s rRNA sequencing. Most of the isolated bacterial strains were resistant to 0.5% bile salts for 48 h and remained viable after 2 h at pH 3.0. Some E. faecalis also showed strong inhibitory activity against Listeria monocytogenes KCTC 3569, KCTC 3586 and KCTC 3710. In the present study, we finally selected E. faecalis AP 216 and AP 45 strain based on probiotic selection criteria such as antimicrobial activity against C. perfringens and tolerance to acid and bile salts. The bacteriocins of E. faecalis AP 216 and AP 45 strains were highly thermostable, showing anticlostridial activities even after incubation at 121℃ for 15 min. These bacteriocinproducing bacteria and/or bacteriocins could be used in feed manufacturing as probiotics as an alternative to antibiotics in the livestock industry. PMID:26761495

  18. Assessment of pheromone response in biofilm forming clinical isolates of high level gentamicin resistant Enterococcus faecalis.

    PubMed

    Jayanthi, S; Ananthasubramanian, M; Appalaraju, B

    2008-01-01

    Twenty five clinical isolates of high level gentamicin resistant Enterococcus faecalis were tested for their biofilm formation and pheromone responsiveness. The biofilm assay was carried out using microtiter plate method. Two isolates out of the 25 (8%) were high biofilm formers and 19 (76%) and four (16%) isolates were moderate and weak biofilm formers respectively. All the isolates responded to pheromones of E. faecalis FA2-2 strain. On addition of pheromone producing E. faecalis FA2-2 strain to these isolates, seven of 19 (37%) moderate biofilm formers developed into high biofilm formers. Similarly one of the 4 (25%) weak biofilm formers developed into high level biofilm former. Twelve (48%) of the 25 isolates were transconjugated by cross streak method using gentamicin as selective marker. This proves that the genetic factor for gentamicin resistance is present in the pheromone responsive plasmid. Among these twelve transaconjugants, seven isolates and one isolate were high biofilm formers on addition of E. faecalis FA2-2 and prior to its addition respectively. Out of the total 25 isolates, eight transconjugants for gentamicin resistance could turn to high biofilm formers on addition of the pheromone producing strain. All the isolates were resistant to more than two antibiotics tested. All the isolates were sensitive to vancomycin. The results indicate the significance of this nosocomial pathogen in biofilm formation and the role of pheromone responding clinical isolates of E. faecalis in spread of multidrug resistance genes.

  19. Multi-drug-resistant Enterococcus faecalis among Egyptian patients with urinary tract infection.

    PubMed

    Abdelkareem, Mohammad Z; Sayed, Mohamed; Hassuna, Noha A; Mahmoud, Mahmoud S; Abdelwahab, Sayed F

    2017-04-01

    The prevalence of Enterococcus faecalis (E. faecalis) infections among Egyptians with urinary tract infection (UTI), their antimicrobial susceptibility and mechanisms of resistance are under investigated. In this study, 300 urine samples were collected from UTI patients to identify E. faecalis. Antimicrobial susceptibility to 18 antimicrobial agents was tested. The presence of aac(6)-Ie-aph(2)Ia, erm(B) and mef(A/E) genes was examined by PCR. Fifty-seven (19%) isolates were identified as E. faecalis. All isolates were sensitive to teicoplanin and were completely resistant to nalidixic acid, cefotaxime and cefadroxil. Multi-drug-resistant (MDR) was found to be 100% with 45 different antibiotypes. The aac(6)Ia-aph(2)Ia gene was found in 100 and 90% of the isolates resistant to gentamicin at concentrations of 120 and 10 μg, respectively. erm(B) and mef(A/E) genes were present in 92.5% (37/40) and 2.5% (1/40) of erythromycin-resistant isolates, respectively. We conclude that there is a high prevalence of E. faecalis in UTI cases with a 100% MDR rate indicating a serious problem in treating infections by this organism in Egypt.

  20. The in vitro Effect of Irrigants with Low Surface Tension on Enterococcus faecalis

    PubMed Central

    Giardino, Luciano; Estrela, Carlos; Generali, Luigi; Mohammadi, Zahed; Asgary, Saeed

    2015-01-01

    Introduction: Due to the complex anatomy of the root canal system and high surface tension of common root canal irrigants (RCI), conducting an investigation on RCIs containing surfactants is a priority. The aim of this in vitro study was to verify the antibacterial potential of RCI with low surface tension in root canals infected with Enterococcus faecalis (E. faecalis). Methods and Materials: Thirty-five extracted human maxillary anterior teeth were prepared and inoculated with E. faecalis for 60 days. After root canal preparation, the teeth were randomly divided to one positive and one negative control groups and 5 experimental groups: Hypoclean/Tetraclean NA, Hypoclean, Tetraclean, NaOCl/Tetraclean and NaOCl. Bacterial growth was observed by turbidity of culture medium and then measured using a UV spectrophotometer. Data were analyzed in three time intervals (pre-instrumentation and, 20 min and 72 h after canal preparation) using the ANOVA and post hoc Tukey’s tests. The level of significance was set at 0.05. Results: The results indicated the presence of E. faecalis in all post-irrigation samples irrespective of the RCI. However, the optical densities in both post-irrigation periods showed bacterial reduction and significant differences between groups. Conclusion: RCI with low surface tension showed antibacterial potential in E. faecalis infected roots. PMID:26229541

  1. Indole production provides limited benefit to Escherichia coli during co-culture with Enterococcus faecalis.

    PubMed

    Pringle, Shelly L; Palmer, Kelli L; McLean, Robert J C

    2017-01-01

    Escherichia coli lives in the gastrointestinal tract and elsewhere, where it coexists within a mixed population. Indole production enables E. coli to grow with other gram-negative bacteria as indole inhibits N-acyl-homoserine lactone (AHL) quorum regulation. We investigated whether E. coli indole production enhanced competition with gram-positive Enterococcus faecalis, wherein quorum signaling is mediated by small peptides. During planktonic co-culture with E. faecalis, the fitness and population density of E. coli tnaA mutants (unable to produce indole) equaled or surpassed that of E. coli wt. During biofilm growth, the fitness of both populations of E. coli stabilized around 100 %, whereas the fitness of E. faecalis declined over time to 85-90 %, suggesting that biofilm and planktonic populations have different competition strategies. Media supplementation with indole removed the competitive advantage of E. coli tnaA in planktonic populations but enhanced it in biofilm populations. E. coli wt and tnaA showed similar growth in Luria-Bertani (LB) broth. However, E. coli growth was inhibited in the presence of filter-sterilized spent LB from E. faecalis, with inhibition being enhanced by indole. Similarly, there was also an inhibition of E. faecalis growth by proteinaceous components (likely bacteriocins) from spent culture media from both E. coli strains. We conclude that E. coli indole production is not a universal competition strategy, but rather works against gram-negative, AHL-producing bacteria.

  2. Vitality of Enterococcus faecalis inside dentinal tubules after five root canal disinfection methods

    PubMed Central

    Vatkar, Niranjan Ashok; Hegde, Vivek; Sathe, Sucheta

    2016-01-01

    Aim: To compare the vitality of Enterococcus faecalis within dentinal tubules after subjected to five root canal disinfection methods. Materials and Methods: Dentin blocks (n = 60) were colonized with E. faecalis. After 4 weeks of incubation, the dentin blocks were divided into one control and five test groups (n = 10 each). The root canals of test groups were subjected to one of the disinfection methods, namely, normal saline (NS), sodium hypochlorite (NaOCl), chlorhexidine digluconate (CHX), neodymium-doped yttrium aluminum garnet (Nd: YAG) laser, and diode laser. The effect of disinfection methods was assessed by LIVE/DEAD BacLight stain under the confocal laser scanning microscopy to determine the “zone of dead bacteria” (ZDB). Mean values were calculated for ZDB and the difference between groups was established. Results: Penetration of E. faecalis was seen to a depth of >1000 μm. Viable bacteria were detected with NS irrigation. NaOCl and CHX showed partial ZDB. When the root canals were disinfected with Nd: YAG and diode lasers, no viable bacteria were found. Conclusion: E. faecalis has the ability to colonize inside dentinal tubules to a depth of >1000 μm. In contrast to conventional irrigants, both Nd: YAG and diode lasers were effective in eliminating the vitality of E. faecalis. NS, NaOCl, and CHX showed viable bacteria remaining in dentinal tubules. PMID:27656064

  3. Collagen degradation and MMP9 activation by Enterococcus faecalis contributes to intestinal anastomotic leak

    PubMed Central

    Shogan, B. D.; Belogortseva, N.; Luong, P. M.; Zaborin, A.; Lax, S.; Bethel, Cindy; Ward, M.; Muldoon, J. P.; Singer, M.; An, G.; Umanskiy, K.; Konda, V.; Shakhsheer, B.; Luo, J.; Klabbers, R.; Hancock, L. E.; Gilbert, J.; Zaborina, O.; Alverdy, J. C.

    2016-01-01

    Even under the most expert care, a properly constructed intestinal anastomosis can fail to heal resulting in leakage of its contents, peritonitis and sepsis. The cause of anastomotic leak remains unknown and its incidence has not changed in decades. Here, we demonstrate that the commensal bacterium Enterococcus faecalis contributes to the pathogenesis of anastomotic leak through its capacity to degrade collagen and to activate tissue matrix metalloprotease-9 (MMP9) in host intestinal tissues. We demonstrate in rats that leaking anastomotic tissues were colonized by E. faecalis strains that showed an increased collagen-degrading activity and also an increased ability to activate host MMP9, both of which contributed to anastomotic leakage. We demonstrate that the E. faecalis genes gelE and sprE were required for E. faecalis-mediated MMP9 activation. Either elimination of E. faecalis strains through direct topical antibiotics applied to rat intestinal tissues or pharmacological suppression of intestinal MMP9 activation prevented anastomotic leak in rats. In contrast, the standard recommended intravenous antibiotics used in patients undergoing colorectal surgery did not eliminate E. faecalis at anastomotic tissues nor did they prevent leak in our rat model. Finally, we show in humans undergoing colon surgery and treated with the standard recommended intravenous antibiotics, that their anastomotic tissues still contained E. faecalis and other bacterial strains with collagen-degrading/MMP9 activity. We suggest that intestinal microbes with the capacity to produce collagenases and to activate host metalloproteinase MMP9 may break down collagen in the gut tissue contributing to anastomotic leak. PMID:25947163

  4. Transfer of tetracycline resistance genes with aggregation substance in food-borne Enterococcus faecalis.

    PubMed

    Choi, Jong-Mi; Woo, Gun-Jo

    2015-04-01

    Enterococcus faecalis has the ability to conjugate with the aid of aggregation substance (AS) and inducible sex pheromones to exchange genetic elements in food matrix. To evaluate the food safety condition and the transferable factor, 250 tetracycline-resistant food-borne E. faecalis were collected in Korea. Among the isolates, a majority of tetracycline-resistant isolates (49.6 %) harbored both the tet(M) and tet(L) genes together, followed by tet(M) (19.6 %), and tet(L) (6.8 %) alone. Also, we found the combination of tet(L)/tet(M)/tet(O) or tet(M)/tet(O). We identified two tet(S) genes including the isolate carrying tet(M) + tet(S) genes. Additionally, most E. faecalis were positive for cpd and ccf (both 96.8 %) followed by cob (57.2 %). Through mating experiments, we confirmed E. faecalis possessing the Int-Tn gene and/or any AS gene successfully transferred tet genes to JH2-2 E. faecalis, whereas neither E. faecalis carrying AS genes nor the Int-Tn gene showed the conjugation. Pulsed-field gel electrophoresis results supported a distinct pattern, implying transfer of genetic information. Our study revealed a high occurrence of tetracycline resistance genes in E. faecalis from various foods. The widespread dissemination of tetracycline resistance genes would be promoted to transfer tetracycline resistance genes by pheromone-mediated conjugation systems.

  5. Development of a genomic site for gene integration and expression in Enterococcus faecalis

    PubMed Central

    DebRoy, Sruti; van der Hoeven, Ransome; Singh, Kavindra V.; Gao, Peng; Harvey, Barrett R.; Murray, Barbara E.; Garsin, Danielle A.

    2012-01-01

    Enterococcus faecalis, a gram-positive opportunistic pathogen, has become one of the leading causes of nosocomial infections. Normally a resident of the gastrointestinal tract, extensive use of antibiotics has resulted in the rise of E. faecalis strains that are resistant to multiple antibiotics. This, compounded with the ability to easily exchange antibiotic determinants with other bacteria, has made certain E. faecalis infections difficult to treat medically. The genetic toolbox for the study of E. faecalis has expanded greatly in recent years, but has lacked methodology to stably introduce a gene in single copy in a non-disruptive manner for complementation or expression of non-native genes. In this study, we identified a specific site in the genome of E. faecalis OG1RF that can serve as an expression site for a gene of interest. This site is well conserved in most of the sequenced E. faecalis genomes. A vector has also been developed to integrate genes into this site by allelic exchange. Using this system, we complemented an in-frame deletion in eutV, demonstrating that the mutation does not cause polar effects. We also generated an E. faecalis OG1RF strain that stably expresses the green fluorescent protein and is comparable to the parent strain in terms of in vitro growth and pathogenicity in C. elegans and mice. Another major advantage of this new methodology is the ability to express integrated genes without the need for maintaining antibiotic selection, making this an ideal tool for functional studies of genes in infection models and co-culture systems. PMID:22542850

  6. Effectiveness of Artocarpus lakoocha extract, poloxamer 407, on Enterococcus faecalis in vitro.

    PubMed

    Teanpaisan, Rawee; Ruangkiatkul, Phattharanan; Thammasitboon, Kewalin; Puripattanavong, Jindaporn; Faroongsarng, Damrongsak

    2013-11-01

    The antiviral activities of Artocarpus lakoocha (A. lakoocha) extract have been reported in a number of studies; however, data regarding its antibacterial capability are limited. The aim of the present study was to examine the effectiveness of A. lakoocha extract, poloxamer 407, on Enterococcus faecalis (E. faecalis). The effect of the antimicrobial activity of A. lakoocha extract and A. lakoocha extract, poloxamer 407, against E. faecalis was investigated. The antibacterial efficacy of A. lakoocha extract, poloxamer 407, against E. faecalis was compared to calcium hydroxide in a tooth model. The minimal inhibitory concentration and minimal bactericidal concentration (MBC) of A. lakoocha extract against E. faecalis were 0.39 ± 0 mg/mL and 3.12 ± 0 mg/mL, respectively; the MBC of calcium hydroxide against E. faecalis was 31.25 ± 0 mg/mL. In the tooth model, the E. faecalis count in all groups significantly decreased as the depth into the dentin increased compared to the control. There were no significant differences between 4% A. lakoocha extract poloxamer and UltraCal XS at any time period (P > 0.05) with one exception: at a depth of 0.6 mm on day 5, UltraCal XS had a significantly greater colonization than 4% A. lakoocha extract poloxamer. A. lakoocha extract, poloxamer 407, might be a useful alternative for antimicrobial medication in endodontic treatment. However, controlled clinical studies to evaluate its efficacy are needed. © 2013 Wiley Publishing Asia Pty Ltd.

  7. Transmission and genetic diversity of Enterococcus faecalis among layer chickens during hatch

    PubMed Central

    2011-01-01

    Background Studies on transmission of Enterococcus faecalis among chickens during hatch have not been carried out so far. Information about vertical transmission and subsequent spreading and colonization of the cloacal mucosa through cloacal 'drinking' during hatch are important to understand the epidemiology of E. faecalis infections. In the present investigation vertical transmission and subsequent spreading and colonization of the cloacal mucosa of chickens by E. faecalis through cloacal 'drinking' were examined. Methods Two different batches of layer chickens originating from 45 weeks old Brown and White Lohmann parents, respectively from the same farm were sampled in the hatcher. Isolates were confirmed to be E. faecalis by polymerase chain reaction (PCR) and further by multilocus sequence typing (MLST) to state their population structure and comparison made to sequence types previously obtained from chicken. Results A total of 480 chickens were swabbed from the cloacae just after hatch and after 24 hours. A total of 101 isolates were confirmed as E. faecalis by a species specific PCR. The prevalence of E. faecalis increased from 14% at 0 h to 97% after 24 h for the Brown Lohmann chickens and from 0.5% to 23% for the White Lohmann flock. The 84 isolates analysed by MLST were distributed on 14 sequence types (ST). Three ST (401, 82 and 249) accounted for 64% of all isolates analysed by MLST after 24 h. ST 82 has previously been reported from amyloid arthropathy and other lesions in poultry. Conclusions The present findings demonstrated a high potential of a few contaminated eggs or embryos to rapidly facilitate the spread of E. faecalis to almost all chickens during hatch. PMID:22017822

  8. Enterococcus faecalis infection activates phosphatidylinositol 3-kinase signaling to block apoptotic cell death in macrophages.

    PubMed

    Zou, Jun; Shankar, Nathan

    2014-12-01

    Apoptosis is an intrinsic immune defense mechanism in the host response to microbial infection. Not surprisingly, many pathogens have evolved various strategies to manipulate this important pathway to benefit their own survival and dissemination in the host during infection. To our knowledge, no attempts have been made to explore the host cell survival signals modulated by the bacterium Enterococcus faecalis. Here, we show for the first time that during early stages of infection, internalized enterococci can prevent host cell (RAW264.7 cells, primary macrophages, and mouse embryonic fibroblasts [MEFs]) apoptosis induced by a wide spectrum of proapoptotic stimuli. Activation of caspase 3 and cleavage of the caspase 3 substrate poly(ADP-ribose) polymerase were inhibited in E. faecalis-infected cells, indicating that E. faecalis protects macrophages from apoptosis by inhibiting caspase 3 activation. This antiapoptotic activity in E. faecalis-infected cells was dependent on the activation of the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway, which resulted in the increased expression of the antiapoptotic factor Bcl-2 and decreased expression of the proapoptotic factor Bax. Further analysis revealed that active E. faecalis physiology was important for inhibition of host cell apoptosis, and this feature seemed to be a strain-independent trait among E. faecalis isolates. Employing a mouse peritonitis model, we also determined that cells collected from the peritoneal lavage fluid of E. faecalis-infected mice showed reduced levels of apoptosis compared to cells from uninfected mice. These results show early modulation of apoptosis during infection and have important implications for enterococcal pathogenesis.

  9. Gene transfer of vancomycin and tetracycline resistances among Enterococcus faecalis during cheese and sausage fermentations.

    PubMed

    Cocconcelli, Pier Sandro; Cattivelli, Daniela; Gazzola, Simona

    2003-12-01

    This study assessed the frequency of transfer of two mobile genetic elements coding for virulence determinants and antibiotic resistance factors, into food associated enterococci during fermentation processes. First, the transfer of the pheromone-inducible pCF10 plasmid, carrying tetracycline resistance and aggregation substance (AS) as virulence factor, between clinical and food strains of Enterococcus faecalis, was investigated in models of cheese and fermented sausage. The experiments demonstrated that even in the absence of selective tetracycline pressure, plasmid pCF10 was transferred from E. faecalis OG1rf cells to food strain E. faecalis BF3098c and that the plasmid subsequently persisted in these environments. Very high frequency of transfer was observed in sausage (10(-3)/recipient) if compared to cheese (10(-6)) and plate mating (10(-4)). Transconjugants were subsequently verified by PCR. The second transmissible element was the plasmid harbouring the vancomycin resistance (VanA phenotype) from E. faecalis A256. The transfer of this antibiotic resistance to a food strain of E. faecalis was studied in vitro and in food models. Although the transfer of vancomycin resistance was achieved in all the environments, the highest conjugation frequencies were observed during the ripening of fermented sausages, reaching 10(-3) transconjugants/recipient cell. PCR confirmed the transfer of the VanA genotype into a food associated Enterococcus strain. This study showed that even in the absence of selective pressure, mobile genetic elements carrying antibiotic resistance and virulence determinants can be transferred at high frequency to food associated enterococci during cheese and sausage fermentation.

  10. Enterococcus species diversity and molecular characterization of biomarker genes in Enterococcus faecalis in Port Blair Bay, Andaman and Nicobar Islands, India.

    PubMed

    Meena, Balakrishnan; Anburajan, Lawrance; Sathish, Thadikamala; Raghavan, Rangamaran Vijaya; Jha, Dilip Kumar; Venkateshwaran, Pitchiah; Das, Apurba Kumar; Dheenan, Palaiya Sukumaran; Vinithkumar, Nambali Valsalan; Dharani, Gopal; Kirubagaran, Ramalingam

    2015-05-15

    This study was performed to evaluate the abundance and diversity of Enterococcus sp. and the distribution of biomarker genes in Enterococcus faecalis in Port Blair Bay, Andaman and Nicobar Islands. The Enterococcus sp. densities at the seven sampling stations were highly influenced by tidal fluctuations and season. The distributions and diversities of species varied in the inner and outer regions of Port Blair Bay. Among the 1816 total isolates, the occurrence of fecal Enterococcus was high (1.78×10(4) CFU/100 mL) in Phoenix Bay. Moreover, 67.76% of the isolates were identified as Enterococcus, and the most frequently identified species were E. hirae, E. avium and E. faecalis. Assessments of antibiotic resistance and biomarker genes revealed the maximum occurrence in the Aberdeen Bay isolates. The most prevalent biomarker genes observed in the E. faecalis isolates were gelE and asa1, whereas cyl was not found among the isolates. In silico sequence analysis of biomarker genes of E. faecalis also revealed that they are evolutionarily well conserved with those of earlier reports. Further, multivariate analysis distinguished the JB, PB and OS stations from the other stations according to distinctive microbial densities and compositions. In addition, the Shannon-Wiener diversity indices and box-whisker plots further facilitated and supported the multivariate results.

  11. Root Canal Irrigation: Chemical Agents and Plant Extracts Against Enterococcus faecalis

    PubMed Central

    Borzini, Letizia; Condò, Roberta; De Dominicis, Paolo; Casaglia, Adriano; Cerroni, Loredana

    2016-01-01

    Background: There are various microorganisms related to intra and extra-radicular infections and many of these are involved in persistent infections. Bacterial elimination from the root canal is achieved by means of the mechanical action of instruments and irrigation as well as the antibacterial effects of the irrigating solutions. Enterococcus faecalis can frequently be isolated from root canals in cases of failed root canal treatments. Antimicrobial agents have often been developed and optimized for their activity against endodontic bacteria. An ideal root canal irrigant should be biocompatible, because of its close contact with the periodontal tissues during endodontic treatment. Sodium hypoclorite (NaOCl) is one of the most widely recommended and used endodontic irrigants but it is highly toxic to periapical tissues. Objectives: To analyze the literature on the chemotherapeutic agent and plant extracts studied as root canal irrigants. In particularly, the study is focused on their effect on Enterococcus faecalis. Method: Literature search was performed electronically in PubMed (PubMed Central, MEDLINE) for articles published in English from 1982 to April 2015. The searched keywords were “endodontic irrigants” and “Enterococcus faecalis” and “essential oil” and “plant extracts”. Results: Many of the studied chemotherapeutic agents and plant extracts have shown promising results in vitro. Conclusion: Some of the considered phytotherapic substances, could be a potential alternative to NaOCl for the biomechanical treatment of the endodontic space. PMID:28217184

  12. Erythromycin- and copper-resistant Enterococcus hirae from marine sediment and co-transfer of erm(B) and tcrB to human Enterococcus faecalis.

    PubMed

    Pasquaroli, Sonia; Di Cesare, Andrea; Vignaroli, Carla; Conti, Giulia; Citterio, Barbara; Biavasco, Francesca

    2014-09-01

    An erythromycin-, copper- and cadmium-resistant isolate of Enterococcus hirae from marine sediment was shown to harbor the plasmid pRE25 and to co-transfer erm(B) and tcrB to Enterococcus faecalis JH2-2. These data highlight the scope for antibiotic resistance selection by the marine environment through heavy metals and its possible involvement in antibiotic-resistant enterococcal infections.

  13. Effects of iron and phytic acid on production of extracellular radicals by Enterococcus faecalis.

    PubMed

    Moore, Danny R; Kotake, Yashige; Huycke, Mark M

    2004-12-01

    Enterococcus faecalis is a human intestinal commensal that produces extracellular superoxide, hydrogen peroxide, and hydroxyl radical while colonizing the intestinal tract. To determine whether dietary factors implicated in colorectal cancer affect oxidant production by E. faecalis, radicals were measured in rats colonized with this microorganism while on diets supplemented with iron or phytic acid. Hydroxyl radical activity was measured by assaying for aromatic hydroxylation products of D-phenylalanine using reverse-phase high-performance liquid chromatography and electrochemical detection. In vitro, as expected, iron enhanced, and phytic acid decreased, hydroxyl radical formation by E. faecalis. For rats colonized with E. faecalis given supplemental dietary iron (740 mg elemental iron as ferric phosphate per kg diet) or phytic acid (1.2% w/w), no differences were found in concentrations of urinary ortho- or meta- isomers of D-phenylalanine compared to rats on a basal diet. Aqueous radicals in colonic contents were further assessed ex vivo by electron spin resonance using 5,5-dimethyl-1-pyrroline-N-oxide as a spin trap. Mixtures of thiyl (sulfur-centered) and oxygen-centered radicals were detected across all diets. In vitro, similar spectra were observed when E. faecalis was incubated with hydrogen sulfide, air-oxidized cysteine, or an alkylsulfide, as typical sulfur-containing compounds that might occur in colonic contents. In conclusion, intestinal colonization with E. faecalis in a rat model generates both thiyl and oxygen-centered radicals in colonic contents. Radical formation, however, was not significantly altered by short-term dietary supplementation with iron or phytic acid.

  14. Antimicrobial Activity of Photodynamic Therapy Against Enterococcus faecalis Before and After Reciprocating Instrumentation in Permanent Molars.

    PubMed

    Pinheiro, Sérgio Luiz; Azenha, Giuliana Rodrigues; Democh, Yasmin Marialva; Nunes, Daniela Camila; Provasi, Silvia; Fontanetti, Giovana Masiero; Duarte, Danilo Antônio; Fontana, Carlos Eduardo; da Silveira Bueno, Carlos Eduardo

    2016-12-01

    The present study sought to evaluate the antimicrobial activity against Enterococcus faecalis of photodynamic therapy applied before and after reciprocating instrumentation of permanent molars. Apical extrusion of debris can cause flare-ups due to introduction of bacteria into the periapical tissues. Eighteen mesial roots from permanent mandibular molars were selected. The crowns were removed to obtain a standard root length of 15 mm. The included mesial roots had an angulation of 10°-40° and canals with independent foramina. The orifice of each mesiolingual canal was sealed with light-curing resin, and the working length was established visually, 1 mm short of the apical foramen. The roots were rendered impermeable and sterilized, and the mesiobuccal canals were contaminated with a standard strain of E. faecalis for 21 days. Specimens were randomly divided into three groups (n = 6): G1, photodynamic therapy performed before instrumentation and irrigation with 0.9% NaCl (saline) solution; G2, photodynamic therapy performed after instrumentation and irrigation with 0.9% NaCl; and G3 (control), instrumentation and irrigation with 2.5% NaOCl (sodium hypochlorite) solution. Canals were shaped with a WaveOne primary file (25.08) and irrigated with 0.9% NaCl. E. faecalis samples were collected before and after each procedure, and the results were analyzed using descriptive statistics and the Kruskal-Wallis and Wilcoxon tests. Significant reductions in E. faecalis were observed when photodynamic therapy was performed before and after instrumentation of the root canal system (p < 0.05). Reciprocating instrumentation significantly reduced E. faecalis colonies in experimentally contaminated root canal systems (p < 0.05). Photodynamic therapy was effective in removing E. faecalis from the root canal system, whether performed before or after reciprocating instrumentation.

  15. Antibiofilm efficacy of silver nanoparticles as a vehicle for calcium hydroxide medicament against Enterococcus faecalis.

    PubMed

    Afkhami, Farzaneh; Pourhashemi, Seyyed Jalal; Sadegh, Mona; Salehi, Yasaman; Fard, Mohammad Javad Kharrazi

    2015-12-01

    The aim of the present study was to investigate antibacterial characteristic and Enterococcus faecalis (E. faecalis) biofilm suppression effect of different vehicles of calcium hydroxide as intracanal medicaments in short and long-term. Fifty-four human single-root teeth were contaminated with E. faecalis bacteria. The teeth were randomly divided into three experimental (n=16) and one control group (n=6). Each group was then exposed to various intracanal medicaments, namely calcium hydroxide paste (group 1), calcium hydroxide with chlorhexidine (group 2), calcium hydroxide with silver nanoparticles suspension (AgNPs) (group 3), and saline as the control group (group 4). Cultures were made from each group after one week and one month, and the number of colonies was counted. Moreover, a sample of each group was examined under electron microscope. Kruskal-Wallis test served for inter-group comparisons, and Mann-Whitney test served for comparison between the two incubation periods. All the intracanal medicaments resulted in significant decrease in number of colonies compared to control group in both incubation periods. After one week, the mixture of calcium hydroxide and AgNPs was the most effective medicament against E. faecalis bacteria (p<.05). No significant difference in antibacterial effect of the medicaments existed after one month incubation period (p>.05). AgNPs was more effective on the E. faecalis biofilm than other tested vehicles in short-term medication. AgNPs seems to have a good potential to be used as an appropriate vehicle of calcium hydroxide in order to eliminate of E. faecalis biofilm from human dentine in short-term. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Characterization of Enterococcus faecalis isolates by chicken embryo lethality assay and ERIC-PCR.

    PubMed

    Blanco, Ana E; Barz, Martin; Cavero, David; Icken, Wiebke; Sharifi, A Reza; Voss, Matthias; Buxadé, Carlos; Preisinger, Rudolf

    2017-08-31

    Enterococcus faecalis is the major causative agent of amyloid arthropathy in chickens. Given the difficulty of estimating the risk from field strains, the embryo lethality assay (ELA) is proposed in this study as a model to predict the virulence of 68 avian E. faecalis strains. Additionally, Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction (ERIC-PCR) was used to characterize the genetic diversity of the E. faecalis strains. The ELA was performed 10 times with subsets of 7-8 E. faecalis strains each on a sample of 9987 eggs, including control groups. An estimated 3-24 colony-forming units were inoculated into the allantoic cavity of 10-day-old embryos. The embryonic mortality rate (EMR) was determined by means of candling the eggs over a period of seven days. The ELA was able to distinguish the virulence of the E. faecalis strains. Twenty-six strains were considered as avirulent strains with an EMR of below 40%. Five strains were highly virulent with an EMR above 80%. The remaining 37 strains were classified as strains of moderate virulence, causing an EMR between 40% and 80%. The highest EMR occurred three and four days post-inoculation (p.i.). From the fourth day p.i., almost no embryonic mortality was observed. Therefore, the ELA could be optimized by reducing experiment duration to four days p.i. ERIC-PCR did not cluster the strains according to its virulence, although ERIC banding patterns revealed a considerable genetic diversity. In conclusion, the ELA can be considered a reliable and useful tool to predict the virulence of avian E. faecalis strains.

  17. Transcriptomic and functional analysis of NaCl-induced stress in Enterococcus faecalis.

    PubMed

    Solheim, Margrete; La Rosa, Sabina Leanti; Mathisen, Thomas; Snipen, Lars G; Nes, Ingolf F; Brede, Dag Anders

    2014-01-01

    The robust physiology of Enterococcus faecalis facilitates tolerance to various stresses. We here report the transcriptional response of E. faecalis V583 to growth in the presence of 6.5% NaCl. Among the early responses observed was an immediate down-regulation of mscL, accompanied by an up-regulation of genes predicted to be involved in uptake of extracellular potassium and glycine betaine. The high NaCl concentration also induced expression of chaperons and cell envelope related traits, such as the enterococcal polysaccharide antigen (epa) locus. Functional genetic analysis revealed reduced salt stress resistance in both epaB and epaE mutants. The reduced salt resistance phenotype associated with the epaB mutant was restored by complementation, hence demonstrating a role of Epa in the physiological robustness of E. faecalis. Furthermore, we demonstrate that Epa confers increased resistance towards multiple cell envelope stress-inducing factors. Accordingly, these findings delineate a potential link between the robust nature of E. faecalis and its ability to perform as a human pathogen, and provide a new perspective on the mechanisms by which Epa contributes to virulence. Notably, the high NaCl concentration also resulted in strict repression of the gelE-sprE operon and impaired gelatinase activity. We demonstrate that NaCl antagonize the GBAP-pheromone dependent induction in a concentration dependent manner.

  18. Biochemical and Genetic Characterization of the Enterococcus faecalis Oxaloacetate Decarboxylase Complex

    PubMed Central

    Repizo, Guillermo D.; Blancato, Víctor S.; Mortera, Pablo; Lolkema, Juke S.

    2013-01-01

    Enterococcus faecalis encodes a biotin-dependent oxaloacetate decarboxylase (OAD), which is constituted by four subunits: E. faecalis carboxyltransferase subunit OadA (termed Ef-A), membrane pump Ef-B, biotin acceptor protein Ef-D, and the novel subunit Ef-H. Our results show that in E. faecalis, subunits Ef-A, Ef-D, and Ef-H form a cytoplasmic soluble complex (termed Ef-AHD) which is also associated with the membrane. In order to characterize the role of the novel Ef-H subunit, coexpression of oad genes was performed in Escherichia coli, showing that this subunit is vital for Ef-A and Ef-D interaction. Diminished growth of the oadA and oadD single deletion mutants in citrate-supplemented medium indicated that the activity of the complex is essential for citrate utilization. Remarkably, the oadB-deficient strain was still capable of growing to wild-type levels but with a delay during the citrate-consuming phase, suggesting that the soluble Ef-AHD complex is functional in E. faecalis. These results suggest that the Ef-AHD complex is active in its soluble form, and that it is capable of interacting in a dynamic way with the membrane-bound Ef-B subunit to achieve its maximal alkalinization capacity during citrate fermentation. PMID:23435880

  19. Effectiveness of Persea major Kopp (Lauraceae) extract against Enterococcus faecalis: a preliminary in vitro study.

    PubMed

    Volpato, Lusiane; Gabardo, Marilisa Carneiro Leão; Leonardi, Denise Piotto; Tomazinho, Paulo Henrique; Maranho, Leila Teresinha; Baratto-Filho, Flares

    2017-03-06

    Persea major Kopp (Lauraceae) is a plant with wound healing, antibacterial, and analgesic properties. The aim of this study was to assess the in vitro antibacterial activity of the concentrated crude extract (CCE) and ethyl acetate fraction (EAF) of this plant against Enterococcus faecalis and compare it with calcium hydroxide [Ca(OH)2] paste and 2% chlorhexidine digluconate (CHX). The plant material was collected, and an extract was prepared according to the requirements of the study (CCE and EAF). The minimum inhibitory concentrations (MICs) of CCE, EAF, Ca(OH)2, Ca(OH)2 + CCE, and CHX against E. faecalis were determined using the broth microdilution method RESULTS: The EAF inhibited E. faecalis at concentrations of 166.50, 83.25, and 41.62 mg mL(-1), and 1.00, 0.50, and 0.25% of CHX solutions showed antimicrobial activity. The MICs of Ca(OH)2 paste were 166.50 and 83.25 mg mL(-1), whereas Ca(OH)2 + CCE showed antimicrobial activity only at a concentration of 166.50 mg mL(-1). CCE showed no inhibitory effect at any of the concentrations tested CONCLUSIONS: The CCE did not show any antimicrobial activity against E. faecalis; however, the EAF was the most effective among the three highest concentrations tested.

  20. Effectiveness of a high purity chlorine dioxide solution in eliminating intracanal Enterococcus faecalis biofilm.

    PubMed

    Herczegh, Anna; Ghidan, Agoston; Friedreich, Dóra; Gyurkovics, Milán; Bendő, Zsolt; Lohinai, Zsolt

    2013-03-01

    We investigated the effectiveness of chlorine dioxide (ClO2) solution in comparison to sodium hypochlorite (NaOCl) and chlorhexidine gluconate (CHX) in the elimination of intracanal Enterococcus faecalis biofilm. Extracted human teeth were inoculated with E. faecalis. After preparation the canals were irrigated with ClO2, NaOCl, CHX or physiologic saline for control. Two and five days later bacterial samples were collected and streaked onto Columbia agar. CFU/mL were counted. The canal walls were investigated by scanning electron microscopy (SEM). The gas phase was investigated in an upside down Petri dish where E. faecalis was inoculated onto blood agar. The irrigants were placed on absorbent paper into the cover. Bacteria were detectable in the control group, but not in any of the irrigants groups. There was a massive reinfection 2 or 5 days after irrigation in the control group. The lowest reinfection was found after the ClO2 treatment. These findings were confirmed by SEM images. We observed an antibacterial effect of ClO2 and NaOCl gas phases on E. faecalis growth, but not of CHX. ClO2 eliminates intracanal biofilm and keeps canal nearly free from bacteria. We suggest the use of high purity ClO2 as a root canal irrigant in clinical practice.

  1. Phage endolysins with broad antimicrobial activity against Enterococcus faecalis clinical strains.

    PubMed

    Proença, Daniela; Fernandes, Sofia; Leandro, Clara; Silva, Filipa Antunes; Santos, Sofia; Lopes, Fátima; Mato, Rosario; Cavaco-Silva, Patrícia; Pimentel, Madalena; São-José, Carlos

    2012-06-01

    Increasing antibiotic resistance of bacterial pathogens has drawn the attention to the potential use of bacteriophage endolysins as alternative antibacterial agents. Here we have identified, characterized, and studied the lytic potential of two endolysins, Lys168 and Lys170, from phages infecting Enterococcus faecalis. Lys168 and Lys170 belong to the cysteine, histidine-dependent amidohydrolases/peptidases (CHAP) and amidase-2 protein families, respectively. Lys168 is quite a unique enterococcal phage endolysin. It shares 95% amino acidic identity with the endolysin of Staphylococcus aureus phage SAP6, which in turn is distantly related to all known CHAP endolysins of S. aureus phages. Lys170 seems to be a natural chimera assembling catalytic and cell-wall-binding domains of different origin. Both endolysins showed a clear preference to act against E. faecalis and they were able to lyse a high proportion of clinical isolates of this species. Specifically, Lys168 and Lys170 lysed more than 70% and 90% of the tested isolates, respectively, which included a panel of diverse and typed strains representative of highly prevalent clonal complexes. Lys170 was active against all tested E. faecalis VRE strains. The quasi specificity toward E. faecalis is discussed considering the nature of the enzymes' functional domains and the structure of the cell wall peptidoglycan.

  2. Antimicrobial Activity of Calcium Hydroxide and Betamethasone on Enterococcus faecalis; An in vitro Assessment

    PubMed Central

    Tabrizizadeh, Mahdi; Rasti, Mojtaba; Ayatollahi, Fatemeh; Mossadegh, Mohammad Hossein; Zandi, Hengameh; Dehghan, Farzad; Mousavi, Zohreh

    2015-01-01

    Introduction: Calcium hydroxide (CH) is one of the most common intracanal medications. Corticosteroids (CS) are used in endodontics because of their anti-inflammatory activity. This study aimed to evaluate the antimicrobial effect of CH+betamethasone and CH+saline against Enterococcus faecalis (E. faecalis) using agar diffusion test and measuring the microbial zone of inhibition (ZOI). Methods and Materials: Four plates containing Mueller-Hinton broth and E. faecalis culture media, were prepared. In each plate, 5 holes (5×3 mm) were created and a creamy mixture of CH+betamethasone was inserted into the holes (10 holes for each material). Two holes with ampicillin disks and two empty holes were used as negative and positive controls, respectively. Plates were incubated for 24 h and then the diameter of microbial ZOI was measured. The pH of each mixture was measured by pH meter. Data were analyzed using the Mann-Whitney U test. Results: The mean diameter of ZOI for CH+betamethasone and CH+saline was 3.4 and 3 mm, respectively. The difference was not significant (P=0.143). The pH was 12.5 for CH+saline and 12.3 CH+betamethasone, respectively. Conclusion: The mixture of CH+betamethasone had good antimicrobial effects against E. faecalis. Further studies are needed to confirm the value of this mixture in clinical settings. PMID:26213541

  3. Antibacterial efficacy of endodontic irrigating solutions and their combinations in root canals contaminated with Enterococcus faecalis.

    PubMed

    Dornelles-Morgental, Renata; Guerreiro-Tanomaru, Juliane Maria; de Faria-Júnior, Norberto Batista; Hungaro-Duarte, Marco Antonio; Kuga, Milton Carlos; Tanomaru-Filho, Mário

    2011-09-01

    The objective of this study was to evaluate the antibacterial efficacy of irrigating solutions and their combinations against Enterococcus faecalis. One hundred ten single-rooted human teeth were inoculated with E. faecalis and incubated for 21 days. Teeth were divided according to the irrigant: Group I (GI), 2.5% sodium hypochlorite solution (NaOCl); GII, 2.5% NaOCl + 10% citric acid; GIII, 2.5% NaOCl + apple cider vinegar; GIV, apple cider vinegar; GV, 2% chlorhexidine solution; GVI, 1% peracetic acid; GVII, saline solution. Microbiological samples were taken after root canal preparation and 7 days later. Data were submitted to ANOVA (5%). All solutions promoted reduction of E. faecalis after instrumentation, but bacterial counts were higher in the final sample. GI, GV, and GVI had lower bacterial counts than the other groups. The irrigating solutions may present activity but do not eradicate E. faecalis in the root canal system. Copyright © 2011 Mosby, Inc. All rights reserved.

  4. Calcium-silicate mesoporous nanoparticles loaded with chlorhexidine for both anti- Enterococcus faecalis and mineralization properties.

    PubMed

    Fan, Wei; Li, Yanyun; Sun, Qing; Ma, Tengjiao; Fan, Bing

    2016-10-21

    In infected periapical tissues, Enterococcus faecalis is one of the most common dominant bacteria. Chlorhexidine has been proved to show strong antibacterial ability against E. faecalis but is ineffective in promoting mineralization for tissues around root apex. Mesoporous calcium-silicate nanoparticles are newly synthesized biomaterials with excellent ability to promote mineralization and carry-release bioactive molecules in a controlled manner. In this study, mesoporous calcium-silicate nanoparticles were functionalized with chlorhexidine and their releasing profile, antibacterial ability, effect on cell proliferation and in vitro mineralization property were evaluated. The chlorhexidine was successfully incorporated into mesoporous calcium-silicate nanoparticles by a mixing-coupling method. The new material could release chlorhexidine as well as Ca(2+) and SiO3(2-) in a sustained manner with an alkaline pH value under different conditions. The antimicrobial ability against planktonic E. faecalis was dramatically improved after chlorhexidine incorporation. The nanoparticles with chlorhexidine showed no negative effect on cell proliferation with low concentrations. On dentin slices, the new synthesized material demonstrated a similar inhibitory effect on E. faecalis as the chlorhexidine. After being immersed in SBF for 9 days, numerous apatite crystals could be observed on surfaces of the material tablets. Mesoporous calcium-silicate nanoparticles loaded with chlorhexidine exhibited release of ions and chlorhexidine, low cytotoxicity, excellent antibacterial ability and in vitro mineralization. This material could be developed into a new effective intra-canal medication in dentistry or a new bone defect filling material for infected bone defects.

  5. The antimicrobial effect of chloroform on Enterococcus faecalis after gutta-percha removal.

    PubMed

    Edgar, Scott W; Marshall, J Gordon; Baumgartner, J Craig

    2006-12-01

    The purpose of this in vitro study was to evaluate the antimicrobial effectiveness of chloroform on Enterococcus faecalis when used as a gutta-percha solvent during endodontic retreatment. Bilaterally matched human teeth were instrumented, infected with E. faecalis, and obturated. The gutta-percha was then removed using either chloroform or saline. Bacterial samples were collected after gutta-percha removal and following additional apical enlargement. A significant difference was seen (p<0.05) between the number of colony forming units (CFU) of E. faecalis for teeth retreated using chloroform (mean 21+56 CFU/ml) versus saline (mean 280+480 CFU/ml). Negative cultures were obtained in 11 of 17 chloroform samples and none of the saline samples. Samples taken after apical enlargement two sizes larger than the original master apical file showed a significant difference (p<0.05) between teeth retreated using chloroform versus saline. Negative cultures were seen in 9 of 17 chloroform samples and 1 of 17 saline samples. This study demonstrated that the use of chloroform during endodontic retreatment significantly reduced intracanal levels of cultivatable E. faecalis.

  6. Clinical and molecular epidemiology of hospital Enterococcus faecalis isolates in eastern France.

    PubMed

    Mulin, Blandine; Bailly, Pascale; Thouverez, Michelle; Cailleaux, Vincent; Cornette, Christian; Dupont, Marie-Jeanne; Talon, Daniel

    1999-03-01

    OBJECTIVE: To report on the occurrence of Enterococcus faecalis hospital isolates obtained during 1 year in hospitals in the Franche-Comté region of France. METHODS: Clinical isolates of E. faecalis of different antibiotic susceptibility phenotypes from hospitalized patients were characterized by pulsed-field gel electrophoresis. Patients with positive cultures were investigated by three case-control studies to identify risk factors for colonization/infection. RESULTS: The crude incidence of colonization/infection was 2.37%, and 4-day and 7-day colonization rates after admission were 10.0% and 6.36%, respectively. The rates of high-level resistance to kanamycin (HLKR) and to gentamicin (HLGR) were 47.1% and 7.1%, respectively. No isolate was resistant to glycopeptides or produced beta-lactamase. The 209 hospital isolates obtained during the study yielded 98 major DNA patterns, of which two were major epidemic patterns including HLKR isolates. No single factor was significantly associated with colonization/infection by HLKR isolates. The length of hospitalization before isolation was associated with colonization by HLGR isolates. CONCLUSIONS: The isolation frequency of E. faecalis strains with acquired resistance to aminoglycoside antibiotics, and the wide dissemination of resistant strains with characteristics that allow them to persist and spread, argue for further large prospective surveys of clinical isolates of E. faecalis in hospitals.

  7. [In vitro activity of ampicillin-ceftriaxone against Enterococcus faecalis isolates recovered from invasive infections].

    PubMed

    Burguer Moreira, Noelia; Nastro, Marcela; Vay, Carlos; Famiglietti, Ángela; Rodríguez, Carlos Hernán

    2016-01-01

    In vitro activity of the combination of ampicillin- ceftriaxone against 30 Enterococcus faecalis isolates recovered from invasive infections in patients admitted to Hospital de Clínicas José de San Martin in the city of Buenos Aires was assessed. Ampicillin- ceftriaxone synergies were determined by microdilution in Müeller-Hinton (MH) broth with and without subinhibitory concentrations of ceftriaxone. Synergy was detected in 22/30 isolates. A decrease in both minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) was observed in 14/30 isolates, whereas in 6/30 isolates the decrease was observed in the MIC value and only in the MBC value in the 2 remaining isolates. The bactericidal activity of the combination showed to be higher at low concentrations of ampicillin (< 1 μg/ml). We detected in vitro synergy using the ampicillin-ceftriaxone combination and thus, its efficacy was confirmed in the treatment of severe infections by E. faecalis.

  8. Cloning, purification, crystallization and preliminary crystallographic analysis of SecA from Enterococcus faecalis

    SciTech Connect

    Meining, Winfried; Scheuring, Johannes; Fischer, Markus; Weinkauf, Sevil

    2006-06-01

    SecA ATPase from E. faecalis has been cloned, overexpressed, purified and crystallized. Crystals belong to space group C2 and diffract to 2.4 Å resolution. The gene coding for SecA from Enterococcus faecalis was cloned and overexpressed in Escherichia coli. In this protein, the lysine at position 6 was replaced by an asparagine in order to reduce sensitivity towards proteases. The modified protein was purified and crystallized. Crystals diffracting to 2.4 Å resolution were obtained using the vapour-diffusion technique. The crystals belong to the monoclinic space group C2, with unit-cell parameters a = 203.4, b = 49.8, c = 100.8 Å, α = γ = 90.0, β = 119.1°. A selenomethionine derivative was prepared and is currently being tested in crystallization trials.

  9. In vitro antimicrobial effect of bacteriophages on human dentin infected with Enterococcus faecalis ATCC 29212.

    PubMed

    Paisano, A F; Spira, B; Cai, S; Bombana, A C

    2004-10-01

    This study assessed the effect of bacteriophages on the viability of Enterococcus faecalis. Human dental roots were inoculated with a suspension of E. faecalis at three different multiplicities of infection - 0.1, 1.0 and 10.0. The phage lysate was able to significantly inhibit bacteria growth when incubated at the multiplicities of infection of 1.0, 10.0 and 0.1. The dental roots were also inoculated with bacteria for 6 days to allow bacterial penetration into the teeth tubules. Addition of the phage lysate to the roots following the 6-day incubation period led to a substantial reduction in bacteria viability. Phage therapy may be an important alternative for the treatment of root canal infections refractory to conventional endodontic therapy.

  10. Purulent pericarditis as a complication of bacteraemic Enterococcus faecalis urinary tract infection.

    PubMed

    Nehme, Fredy; Gitau, Jane; Liu, Jing

    2017-03-15

    Purulent pericarditis is a rare clinical entity in the modern antibiotic era. The most common portal of entry is thought to be direct extension from a primary lung source and is usually caused by Staphylococcus aureus, Streptococcus pneumoniae or Haemophilus influenzae We report the case of a man aged 69 years who presented with purulent pericarditis due to Enterococcus faecalis likely caused by haematogenous spread from a urinary tract source. Urgent pericardiocentesis was vital and restored his haemodynamic stability. He was treated for a total duration of 4 weeks with susceptible antibiotics. Echocardiography 3 weeks later showed persistent resolution of the pericardial effusion. This case shows that prompt diagnosis and drainage of the pericardial effusion are vital to achieve a positive outcome in purulent pericarditis. To the best of our knowledge, this is the first reported case of purulent pericarditis caused by E. faecalis from a urinary tract source. 2017 BMJ Publishing Group Ltd.

  11. Transcriptomic response of Enterococcus faecalis V583 to low hydrogen peroxide levels.

    PubMed

    Yan, Xue; Budin-Verneuil, Aurélie; Verneuil, Nicolas; Gilmore, Michael S; Artigaud, Sébastien; Auffray, Yanick; Pichereau, Vianney

    2015-02-01

    Enterococcus faecalis is a Gram-positive commensal bacterium inhabiting the gastrointestinal tracts of human and other mammals, but is also increasingly recognized as an opportunistic human pathogen. Oxidative stress is one of the major challenges encountered by enterococci, both in their natural environment and during infection. In this paper, we evaluated the transcriptomic response of E. faecalis to oxidative stress, and showed that transcript abundance was reduced for 93 genes and increased for 39 genes during growth in medium containing 1.75 mM H2O2. The presence of hydrogen peroxide affected several metabolic pathways, including a large decrease in ethanolamine utilization and methylglyoxal metabolism, and an increase in transcript abundance for several transport systems. In particular, four operons encoding iron transporters appeared highly induced. By contrast, in our experimental conditions, the expression of most of the genes known to be involved in the enterococcal response to oxidative stress, did not appear significantly altered.

  12. Intrathecal/Intraventricular Linezolid in Multidrug-Resistant Enterococcus faecalis Ventriculitis

    PubMed Central

    Lich, Brian F.; Conner, Andrew K.; Burks, Joshua D.; Glenn, Chad A.; Sughrue, Michael E.

    2016-01-01

    Background The use of intrathecal antibiotic therapy for the treatment of ventriculitis and/or meningitis has demonstrated efficacy especially when sterilization of the cerebrospinal fluid is not possible with intravenous antibiotics alone. Case Description We describe the successful treatment of Enterococcus faecalis ventriculitis utilizing intrathecal linezolid in a 32-year-old female patient with severe allergy to vancomycin, prohibitive bacterial susceptibilities, and failure of previous attempts to sterilize the cerebrospinal fluid despite multimodal treatment. Conclusion Intrathecal linezolid is a useful treatment in the setting of multidrug-resistant bacterial ventriculitis. We present a useful dosing regimen for the administration of intrathecal linezolid. PMID:27867829

  13. Infective endocarditis caused by Enterococcus faecalis treated with continuous infusion of ampicillin without adjunctive aminoglycosides.

    PubMed

    Ogawa, Taku; Sato, Masatoshi; Yonekawa, Shinsuke; Nakagawa, Chiyo; Uno, Kenji; Kasahara, Kei; Maeda, Koichi; Konishi, Mitsuru; Mikasa, Keiichi

    2013-01-01

    Aminoglycosides are useful antimicrobial agents for treating infective endocarditis; however, they occasionally cause troublesome side effects, such as nephrotoxicity and ototoxicity. We herein report a case of infective endocarditis caused by Enterococcus faecalis that was treated successfully with continuous infusion of ampicillin without adjunctive aminoglycosides. The serum ampicillin concentrations were higher than the minimal inhibitory concentration for the target strain. Although the use of ampicillin monotherapy is currently avoided because double β-lactam therapy is reportedly more effective, continuous penicillin administration remains an effective therapeutic choice for treating infective endocarditis.

  14. VanE-type vancomycin-resistant Enterococcus faecalis clinical isolates from Australia.

    PubMed

    Abadía-Patiño, Lorena; Christiansen, Keryn; Bell, Jan; Courvalin, Patrice; Périchon, Bruno

    2004-12-01

    Three distinct Enterococcus faecalis VanE-type isolates-BM4574, BM4575, and BM4576-obtained in Australia were studied. Expression of the resistance genes was constitutive in BM4575, probably due to a 2-bp deletion into the vanSE gene, and inducible in BM4574 and BM4576. Transcription analysis of the vanE operons suggested that the five genes were cotranscribed from an initiation site located 25 bp upstream from the ATG start codon of vanE.

  15. First Report of the Multidrug Resistance Gene cfr in Enterococcus faecalis of Animal Origin

    PubMed Central

    Liu, Yang; Wang, Yang; Wu, Congming; Shen, Zhangqi; Schwarz, Stefan; Du, Xiang-Dang; Dai, Lei; Zhang, Wanjiang

    2012-01-01

    The multiresistance gene cfr was identified for the first time in an Enterococcus faecalis isolate of animal origin. The 32,388-bp plasmid pEF-01, which carried the cfr gene, was sequenced completely. Three copies of the insertion sequence IS1216 were identified in pEF-01, and the detection of a cfr- and IS1216-containing amplicon by inverse PCR suggests that IS1216 may play a role in the dissemination of cfr by a recombination process. PMID:22203597

  16. Successful salvage treatment of native valve Enterococcus faecalis infective endocarditis with telavancin: two case reports.

    PubMed

    Thompson, Mickala M; Hassoun, Ali

    2017-07-01

    Infective endocarditis (IE) one-year mortality rates approach 40%. Here, we report two native valve Enterococcus faecalis IE cases in patients successfully treated with telavancin. An 88-year-old with mitral valve endocarditis and a penicillin allergy, initially treated with intravenous vancomycin, was switched to telavancin. A 69-year-old, who previously received amoxicillin and intravenous vancomycin for presumed enterococcal bacteraemia, was diagnosed with dual valve endocarditis for which he received telavancin. Both received six weeks of telavancin. Neither had telavancin-related adverse events, evidence of infection at six months, nor required telavancin dosing adjustments. Documented use of novel treatments for serious enterococcal infections is needed.

  17. Pheromone-responsive conjugative vancomycin resistance plasmids in Enterococcus faecalis isolates from humans and chicken feces.

    PubMed

    Lim, Suk-Kyung; Tanimoto, Koichi; Tomita, Haruyoshi; Ike, Yasuyoshi

    2006-10-01

    The drug resistances and plasmid contents of a total of 85 vancomycin-resistant enterococcus (VRE) strains that had been isolated in Korea were examined. Fifty-four of the strains originated from samples of chicken feces, and 31 were isolated from hospital patients in Korea. Enterococcus faecalis KV1 and KV2, which had been isolated from a patient and a sample of chicken feces, respectively, were found to carry the plasmids pSL1 and pSL2, respectively. The plasmids transferred resistances to vancomycin, gentamicin, kanamycin, streptomycin, and erythromycin to E. faecalis strains at a high frequency of about 10(-3) per donor cell during 4 hours of broth mating. E. faecalis strains containing each of the pSL plasmids formed clumps after 2 hours of incubation in broth containing E. faecalis FA2-2 culture filtrate (i.e., the E. faecalis sex pheromone), and the plasmid subsequently transferred to the recipient strain in a 10-min short mating in broth, indicating that the plasmids are responsive to E. faecalis pheromones. The pSL plasmids did not respond to any of synthetic pheromones for the previously characterized plasmids. The pheromone specific for pSL plasmids has been designated cSL1. Southern hybridization analysis showed that specific FspI fragments from each of the pSL plasmids hybridized with the aggregation substance gene (asa1) of the pheromone-responsive plasmid pAD1, indicating that the plasmids had a gene homologous to asa1. The restriction maps of the plasmids were identical, and the size of the plasmids was estimated to be 128.1 kb. The plasmids carried five drug resistance determinants for vanA, ermB, aph(3'), aph(6'), and aac(6')/aph(2'), which encode resistance to vancomycin, erythromycin, kanamycin, streptomycin, and gentamicin/kanamycin, respectively. Nucleotide sequence analyses of the drug resistance determinants and their flanking regions are described in this report. The results described provide evidence for the exchange of genetic information

  18. Enterococcus faecalis Subverts and Invades the Host Urothelium in Patients with Chronic Urinary Tract Infection

    PubMed Central

    Horsley, Harry; Malone-Lee, James; Holland, David; Tuz, Madeleine; Hibbert, Andrew; Kelsey, Michael; Kupelian, Anthony; Rohn, Jennifer L.

    2013-01-01

    Bacterial urinary tract infections (UTI) are a major growing concern worldwide. Uropathogenic Escherichia coli has been shown to invade the urothelium during acute UTI in mice and humans, forming intracellular reservoirs that can evade antibiotics and the immune response, allowing recurrence at a later date. Other bacterial species, such as Staphylococcus saprophyticus, Klebsiella pneumonia and Salmonella enterica have also been shown to be invasive in acute UTI. However, the role of intracellular infection in chronic UTI causing more subtle lower urinary tract symptoms (LUTS), a particular problem in the elderly population, is poorly understood. Moreover, the species of bacteria involved remains largely unknown. A previous study of a large cohort of non-acute LUTS patients found that Enterococcus faecalis was frequently found in urine specimens. E. faecalis accounts for a significant proportion of chronic bladder infections worldwide, although the invasive lifestyle of this uropathogen has yet to be reported. Here, we wanted to explore this question in more detail. We harvested urothelial cells shed in response to inflammation and, using advanced imaging techniques, inspected them for signs of bacterial pathology and invasion. We found strong evidence of intracellular E. faecalis harboured within urothelial cells shed from the bladder of LUTS patients. Furthermore, using a culture model system, these patient-isolated strains of E. faecalis were able to invade a transitional carcinoma cell line. In contrast, we found no evidence of cellular invasion by E. coli in the patient cells or the culture model system. Our data show that E. faecalis is highly competent to invade in this context; therefore, these results have implications for both the diagnosis and treatment of chronic LUTS. PMID:24363814

  19. Antibacterial Efficacy of Different Concentrations of Sodium Hypochlorite Gel and Solution on Enterococcus faecalis Biofilm

    PubMed Central

    Zand, Vahid; Lotfi, Mehrdad; Soroush, Mohammad Hosein; Abdollahi, Amir Ardalan; Sadeghi, Mehdi; Mojadadi, Ali

    2016-01-01

    Introduction: This in vitro study compared the antibacterial efficacy of 2.5% sodium hypochlorite gel and 2.5% and 5.25% sodium hypochlorite solutions on Enterococcus faecalis (E. faecalis) biofilm. Methods and Materials: The root canals of 60 extracted human single-rooted teeth were contaminated with E. faecalis and incubated for 6 weeks. The samples were randomly assigned to three experimental groups and one control group (n=15). The study protocol in the experimental groups consisted of injection of 5 mL of each irrigant into the root canals. Samples were collected from the root canal walls and 1:10 serial dilutions were prepared and added to Muller Hinton Agar (MHA) plates and incubated at 37°C for 48 h. A classic colony counting technique was used for determining vital E. faecalis bacterial counts in MHA plates. The Kruskal-Wallis test was used for statistical analysis of the data. The level of significance was set at 0.05. Results: The antibacterial effect of the irrigants in all three experimental groups was significantly greater than the control group (P<0.05), with no significant difference between 2.5% and 5.25% NaOCl solutions (P>0.05). The effect of 2.5% and 5.25% NaOCl solutions were significantly superior to 2.5% NaOCl gel (P<0.05). Conclusion: Under the limitations of this study, 2.5% NaOCl gel was effective in reducing E. faecalis counts; however this effect was less than that of NaOCl solutions. PMID:27790262

  20. Large-Scale Screening of a Targeted Enterococcus faecalis Mutant Library Identifies Envelope Fitness Factors

    PubMed Central

    Rigottier-Gois, Lionel; Alberti, Adriana; Houel, Armel; Taly, Jean-François; Palcy, Philippe; Manson, Janet; Pinto, Daniela; Matos, Renata C.; Carrilero, Laura; Montero, Natalia; Tariq, Muhammad; Karsens, Harma; Repp, Christian; Kropec, Andrea; Budin-Verneuil, Aurélie; Benachour, Abdellah; Sauvageot, Nicolas; Bizzini, Alain; Gilmore, Michael S.; Bessières, Philippe; Kok, Jan; Huebner, Johannes; Lopes, Fatima; Gonzalez-Zorn, Bruno; Hartke, Axel; Serror, Pascale

    2011-01-01

    Spread of antibiotic resistance among bacteria responsible for nosocomial and community-acquired infections urges for novel therapeutic or prophylactic targets and for innovative pathogen-specific antibacterial compounds. Major challenges are posed by opportunistic pathogens belonging to the low GC% Gram-positive bacteria. Among those, Enterococcus faecalis is a leading cause of hospital-acquired infections associated with life-threatening issues and increased hospital costs. To better understand the molecular properties of enterococci that may be required for virulence, and that may explain the emergence of these bacteria in nosocomial infections, we performed the first large-scale functional analysis of E. faecalis V583, the first vancomycin-resistant isolate from a human bloodstream infection. E. faecalis V583 is within the high-risk clonal complex 2 group, which comprises mostly isolates derived from hospital infections worldwide. We conducted broad-range screenings of candidate genes likely involved in host adaptation (e.g., colonization and/or virulence). For this purpose, a library was constructed of targeted insertion mutations in 177 genes encoding putative surface or stress-response factors. Individual mutants were subsequently tested for their i) resistance to oxidative stress, ii) antibiotic resistance, iii) resistance to opsonophagocytosis, iv) adherence to the human colon carcinoma Caco-2 epithelial cells and v) virulence in a surrogate insect model. Our results identified a number of factors that are involved in the interaction between enterococci and their host environments. Their predicted functions highlight the importance of cell envelope glycopolymers in E. faecalis host adaptation. This study provides a valuable genetic database for understanding the steps leading E. faecalis to opportunistic virulence. PMID:22194979

  1. High genetic diversity of Enterococcus faecium and Enterococcus faecalis clinical isolates by pulsed-field gel electrophoresis and multilocus sequence typing from a hospital in Malaysia.

    PubMed

    Weng, Poh Leng; Ramli, Ramliza; Shamsudin, Mariana Nor; Cheah, Yoke-Kqueen; Hamat, Rukman Awang

    2013-01-01

    Little is known on the genetic relatedness and potential dissemination of particular enterococcal clones in Malaysia. We studied the antibiotic susceptibility profiles of Enterococcus faecium and Enterococcus faecalis and subjected them to pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). E. faecium and E. faecalis displayed 27 and 30 pulsotypes, respectively, and 10 representative E. faecium and E. faecalis isolates (five each) yielded few different sequence types (STs): ST17 (2 isolates), ST78, ST203, and ST601 for E. faecium, and ST6, ST16, ST28, ST179, and ST399 for E. faecalis. Resistance to tazobactam-piperacillin and ampicillin amongst E. faecium isolates was highly observed as compared to E. faecalis isolates. All of the isolates were sensitive to vancomycin and teicoplanin. The presence of epidemic and nosocomial strains of selected E. faecium STs: 17, 78, and 203 and E. faecalis ST6 as well as high rates of resistance to multiple antibiotics amongst E. faecium isolates is of a particular concern.

  2. High Genetic Diversity of Enterococcus faecium and Enterococcus faecalis Clinical Isolates by Pulsed-Field Gel Electrophoresis and Multilocus Sequence Typing from a Hospital in Malaysia

    PubMed Central

    Weng, Poh Leng; Ramli, Ramliza; Shamsudin, Mariana Nor; Cheah, Yoke-Kqueen; Hamat, Rukman Awang

    2013-01-01

    Little is known on the genetic relatedness and potential dissemination of particular enterococcal clones in Malaysia. We studied the antibiotic susceptibility profiles of Enterococcus faecium and Enterococcus faecalis and subjected them to pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). E. faecium and E. faecalis displayed 27 and 30 pulsotypes, respectively, and 10 representative E. faecium and E. faecalis isolates (five each) yielded few different sequence types (STs): ST17 (2 isolates), ST78, ST203, and ST601 for E. faecium, and ST6, ST16, ST28, ST179, and ST399 for E. faecalis. Resistance to tazobactam-piperacillin and ampicillin amongst E. faecium isolates was highly observed as compared to E. faecalis isolates. All of the isolates were sensitive to vancomycin and teicoplanin. The presence of epidemic and nosocomial strains of selected E. faecium STs: 17, 78, and 203 and E. faecalis ST6 as well as high rates of resistance to multiple antibiotics amongst E. faecium isolates is of a particular concern. PMID:23819125

  3. Effect of Nanosilver Gel, Chlorhexidine Gluconate, and Camphorated Phenol on Enterococcus faecalis Biofilm.

    PubMed

    Bo, Dong; Kayombo, Cecilia Marcellino

    2014-01-01

    Aim. To assess the effectiveness of nanosilver gel (NSG) in comparison to chlorhexidine gluconate (CHX) and camphorated phenol (CP) against Enterococcus faecalis (E.f) biofilm. Methods and Materials. Two tests were done, methyl thiazolyl tetrazolium (MTT) assay and confocal laser scanning microscopy (CLSM) analysis, to determine the effectiveness of NSG, CHX, and CP on E.f biofilm. Polystyrene microtiter 96- and 6-well plates were used for MTT and CLSM, respectively. Nanosilver gel was in three concentrations (0.05%, 0.1%, and 0.2%), chlorhexidine gluconate used was 2%, and camphorated phenol and normal saline were as control. Analysis was done using one-way ANOVA; the post hoc test was run for multiple comparisons. The level of statistical significance was set at P < 0.05. Results. One-way ANOVA showed significant differences among groups (0.05% NSG and CP, 0.1% NSG and CP, 0.2% NSG and CP, 0.1% NSG and 2% CHX, 0.2% and NSG and 2% CHX) (P < 0.001) and also showed significant difference between groups (P < 0.001), f-ratio 87.823. A post hoc Tukey's test revealed no significant difference between chlorhexidine gluconate and 0.05% nanosilver gel (P > 0.05). Conclusions. 0.1% and 0.2% nanosilver gel is more effective on Enterococcus faecalis biofilm as compared to chlorhexidine gluconate and camphorated phenol.

  4. Enterococcal surface protein Esp does not facilitate intestinal colonization or translocation of Enterococcus faecalis in clindamycin-treated mice.

    PubMed

    Pultz, Nicole J; Shankar, Nathan; Baghdayan, Arto S; Donskey, Curtis J

    2005-01-15

    Enterococcal surface protein (Esp) is a cell wall-associated protein of Enterococcus faecalis that has been identified as a potential virulence factor. We used a mouse model to examine whether Esp facilitates intestinal colonization or translocation of E. faecalis to mesenteric lymph nodes. After clindamycin treatment, similar levels of high-density colonization were established after orogastric inoculation of an E. faecalis isolate containing the esp gene within a large pathogenicity island and an isogenic mutant created by allelic replacement of the esp gene with a chloramphenicol resistance cassette (P=0.7); translocation to mesenteric lymph nodes was detected in 3 of 12 (25%) mice in both groups. Isogenic mutants of FA2-2 (a plasmid-free derivative of E. faecalis strain JH2) with or without the esp gene failed to establish colonization of clindamycin-treated mice. These results suggest that Esp does not facilitate intestinal colonization or translocation of E. faecalis.

  5. Detection of the esp gene in high-level gentamicin resistant Enterococcus faecalis strains from pet animals in Japan.

    PubMed

    Harada, Tetsuya; Tsuji, Noboru; Otsuki, Koichi; Murase, Toshiyuki

    2005-03-20

    We investigated the prevalence of the esp gene and the susceptibility to gentamicin in Enterococcus faecalis and E. faecium strains obtained from pet animals. Nine of 30 E. faecalis and 2 of 38 E. faecium strains from the pet animals had the esp gene. Three esp-positive E. faecalis strains, which were isolated from two dogs and a cat, showed gentamicin MICs of > or =256 microg/ml and harbored the high-level gentamicin resistance (HLGR) gene, aac(6')-Ie-aph(2'')-Ia. Of the nine esp-positive E. faecalis strains, five, including the three strains with the HLGR gene, were closely related by numerical analysis of PFGE patterns. Longitudinal investigation needs to elucidate whether the HLGR gene was incorporated into a subpopulation of the esp-positive E. faecalis.

  6. Chemical Compositions and Aroma Evaluation of Volatile Oil from the Industrial Cultivation Medium of Enterococcus faecalis.

    PubMed

    Ono, Toshirou; Usami, Atsushi; Nakaya, Satoshi; Maeba, Keisuke; Yonejima, Yasunori; Toyoda, Masanori; Ikeda, Atsushi; Miyazawa, Mitsuo

    2015-01-01

    Enterococcus faecalis is one of the major lactic acid bacterium (LAB) species colonizing the intestines of animals and humans. The characteristic odor of the volatile oils obtained from both the liquid medium after incubation (MAI) and liquid medium before incubation (MBI) in the cultivation process of E. faecalis was investigated to determine the utility of the liquid medium. In total, fifty-six and thirty-two compounds were detected in the volatile oils from the MAI (MAI oil) and MBI (MBI oil), respectively. The principle components of MAI oil were 2,5-dimethylpyrazine (19.3%), phenylacetaldehyde (19.3%), and phenylethyl alcohol (9.3%). The aroma extract dilution analysis (AEDA) method was performed using gas chromatography-olfactometry (GC-O). The total number of aroma-active compounds identified in the volatile oil from MBI and MAI was thirteen compounds; in particular, 5-methyl-2-furanmethanol, phenylacetaldehyde, and phenylethyl alcohol were the most primary aroma-active compounds in MAI oil. These results imply that the industrial cultivation medium after incubation of E. faecalis may be utilized as a source of volatile oils.

  7. Involvement of PhoP-PhoS homologs in Enterococcus faecalis virulence.

    PubMed

    Teng, Fang; Wang, Ling; Singh, Kavindra V; Murray, Barbara E; Weinstock, George M

    2002-04-01

    Eleven PhoP-PhoS homolog pairs were identified by searching the Enterococcus faecalis V583 genome sequence database at The Institute for Genomic Research with the Bacillus subtilis PhoP-PhoS sequences. Each pair appears to be a potential two-component system composed of a response regulator and a sensor kinase. Seven of the homologs were disrupted in E. faecalis strain OG1RF. TX10293, a mutant disrupted in one of these genes (etaR, the first gene of the gene pair designated etaRS), showed delayed killing and a higher 50% lethal dose in a mouse peritonitis model. The predicted EtaR protein sequence showed greatest similarity to LisR of Listeria monocytogenes (77%) and CsrR of Streptococcus pyogenes (70%); EtaS is 53% similar to LisK and 54% similar to CsrS. When grown in vitro, the TX10293 mutant was more sensitive to low pH (pH 3.4) and more resistant to high temperature (55 degrees C) than wild-type OG1RF. In conclusion, many potential two-component systems are identified for E. faecalis, one of which, EtaRS, was shown to be involved in stress response and virulence.

  8. The Spx Regulator Modulates Stress Responses and Virulence in Enterococcus faecalis

    PubMed Central

    Kajfasz, Jessica K.; Mendoza, Jorge E.; Gaca, Anthony O.; Miller, James H.; Koselny, Kristy A.; Giambiagi-deMarval, Marcia; Wellington, Melanie; Abranches, Jacqueline

    2012-01-01

    The ability to cope with endogenous or host-generated reactive oxygen species is considered a key virulence attribute of the opportunistic pathogen Enterococcus faecalis, a leading cause of hospital-acquired infections. In this study, we used in silico and mutational analyses to identify and characterize the role of the Spx global regulator in oxidative stress tolerance and virulence in E. faecalis. While the Δspx strain grew as well as the wild-type strain under anaerobic conditions, the mutant strain exhibited impaired growth under aerobic conditions and was highly sensitive to oxidative stress agents. The spx mutant strain was also sensitive to a variety of other stressful conditions, including antibiotic stress and killing by the mouse-derived macrophage cell line J774. Using a murine model of foreign body-associated peritonitis, we demonstrated that the ability of the Δspx strain to colonize the peritoneum and disseminate in the bloodstream was significantly reduced compared to that of the parent strain. Transcriptional analysis revealed that a large number of known oxidative stress genes are under positive control by Spx. Collectively, our results show that Spx is a major stress gene regulator and is implicated in the pathophysiology of E. faecalis. The relationship of Spx to other oxidative stress regulators is also discussed. PMID:22508863

  9. Incorporation of Exogenous Fatty Acids Protects Enterococcus faecalis from Membrane-Damaging Agents

    PubMed Central

    Saito, Holly E.; Harp, John R.

    2014-01-01

    Enterococcus faecalis is a commensal bacterium of the mammalian intestine that can persist in soil and aquatic systems and can be a nosocomial pathogen to humans. It employs multiple stress adaptation strategies in order to survive such a wide range of environments. Within this study, we sought to elucidate whether membrane fatty acid composition changes are an important component for stress adaptation. We noted that E. faecalis OG1RF was capable of changing its membrane composition depending upon growth phase and temperature. The organism also readily incorporated fatty acids from bile, serum, and medium supplemented with individual fatty acids, often dramatically changing the membrane composition such that a single fatty acid was predominant. Growth in either low levels of bile or specific individual fatty acids was found to protect the organism from membrane challenges such as high bile exposure. In particular, we observed that when grown in low levels of bile, serum, or the host-derived fatty acids oleic acid and linoleic acid, E. faecalis was better able to survive the antibiotic daptomycin. Interestingly, the degree of membrane saturation did not appear to be important for protection from the stressors examined here; instead, it appears that a specific fatty acid or combination of fatty acids is critical for stress resistance. PMID:25128342

  10. Adherence and intracellular survival within human macrophages of Enterococcus faecalis isolates from coastal marine sediment.

    PubMed

    Sabatino, Raffaella; Di Cesare, Andrea; Pasquaroli, Sonia; Vignaroli, Carla; Citterio, Barbara; Amiri, Mehdi; Rossi, Luigia; Magnani, Mauro; Mauro, Alessandro; Biavasco, Francesca

    2015-09-01

    Enterococcus faecalis is part of the human intestinal microbiota and an important nosocomial pathogen. It can be found in the marine environment, where it is also employed as a fecal indicator. To assess the pathogenic potential of marine E. faecalis, four strains isolated from marine sediment were analyzed for their ability to survive in human macrophages. Escherichia coli DH5α was used as a negative control. The number of adherent and intracellular bacteria was determined 2.5 h after the infection (T0) and after further 24h (T24) by CFU and qPCR counts. At T24 adherent and intracellular enterococcal CFU counts were increased for all strains, the increment in intracellular bacteria being particularly marked. No CFU of E. coli DH5α were detected. In contrast, qPCR counts of intracellular enterococcal and E. coli bacteria were similar at both time points. These findings suggest that whereas E. coli was killed within macrophages (no CFU, positive qPCR), the E. faecalis isolates not only escaped killing, but actually multiplied, as demonstrated by the increase in the viable cell population. These findings support earlier data by our group, further documenting that marine sediment can be a reservoir of pathogenic enterococci.

  11. Effects of ozone and photo-activated disinfection against Enterococcus faecalis biofilms in vitro.

    PubMed

    Tuncay, Ö; Dinçer, A N; Kuştarcı, A; Er, Ö; Dinç, G; Demirbuga, S

    2015-01-01

    The purpose of this study was to compare the antibacterial effects of gaseous ozone (O3) and photo-activated disinfection (PAD) methods against Enterococcus faecalis (E. faecalis) biofilms. Sixty-five human mandibular premolars with straight root canals were selected. After root canal preparation, the samples were sterilized and placed into eppendorf tubes with 1 mL brain heart infusion broth containing 1.5×10(8) colony-forming units (CFUs)/mL of E. faecalis. The contaminated samples were then divided into four groups (n=15) according to the disinfection method used: Group 1, Saline (positive control); Group 2, NaOCl (negative control); Group 3, Gaseous O3; and Group 4, PAD. Three non-contaminated teeth were used to control the infection and sterilization process. The CFUs were counted and the data were analyzed statistically. There was a statistically significant difference between the experimental and control groups (P<0.05). The saline group had the highest number of remaining microorganisms. Complete sterilization was achieved in the 2.5% NaOCl group. There were no statistically differences between PAD and gaseous O3 (P>0.05). Both PAD and gaseous O3 have a significant antibacterial effect on infected root canals. However, 2.5% NaOCl was superior in terms of its antimicrobial abilities compared with the other disinfection procedures.

  12. Potential for nosocomial transmission of Enterococcus faecalis from surfaces in dental operatories.

    PubMed

    Vidana, R; Sillerström, E; Ahlquist, M; Lund, B

    2015-06-01

    To assess the potential for nosocomial transmission of Enterococcus faecalis during root canal treatment by measuring its occurrence on surfaces in dental operatories in relation to the efficacy of disinfection routines. Eight dental clinics (two endodontic specialist clinics and six general dentistry clinics) were included. Bacterial sampling was conducted in duplicate after root canal treatment and collected before and after disinfection from four surfaces expected to be frequently disinfected and six surfaces expected to be occasionally disinfected. A total of 320 samples were collected. Overall, 40.6% (n = 130) exhibited bacterial growth, mostly consisting of environmental bacteria (36.3%) and to a lesser extent of bacteria from salivary contamination (3.4%). Only three surfaces, all of which were probably seldomly disinfected, were positive for E. faecalis (0.9%). Disinfection routines resulted in an increased contamination in the majority of general dentistry clinics: 64% (32/50) of the surfaces were contaminated prior to and 70% (35/50) after disinfection. Conversely, disinfection of surfaces in the specialist clinics reduced contamination levels by 10%. The origin of E. faecalis in secondary root canal infections remains unclear, as the potential for nosocomial transmission of enterococci from environmental surfaces in dental surgeries appears to be very small. The incorrect or ineffective disinfection procedures in general dentistry clinics needs to be addressed to counteract the risk for bacterial transmission in dental operatories. © 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  13. Enterococcus faecalis zinc-responsive proteins mediate bacterial defence against zinc overload, lysozyme and oxidative stress.

    PubMed

    Abrantes, Marta C; Kok, Jan; Silva Lopes, Maria de Fátima

    2014-12-01

    Two Enterococcus faecalis genes encoding the P-type ATPase EF1400 and the putative SapB protein EF0759 were previously shown to be strongly upregulated in the presence of high concentrations of zinc. In the present work, we showed that a Zn(2+)-responsive DNA-binding motif (zim) is present in the promoter regions of these genes. Both proteins were further studied with respect to their involvement in zinc homeostasis and invasion of the host. EF0759 contributed to intramacrophage survival by an as-yet unknown mechanism(s). EF1400, here renamed ZntAEf, is an ATPase with specificity for zinc and plays a role in dealing with several host defences, i.e. zinc overload, oxidative stress and lysozyme; it provides E. faecalis cells with the ability to survive inside macrophages. As these three host defence mechanisms are important at several sites in the host, i.e. inside macrophages and in saliva, this work suggested that ZntAEf constitutes a crucial E. faecalis defence mechanism that is likely to contribute to the ability of this bacterium to endure life inside its host.

  14. Genome-based characterization of hospital-adapted Enterococcus faecalis lineages

    PubMed Central

    Raven, Kathy E.; Reuter, Sandra; Gouliouris, Theodore; Reynolds, Rosy; Russell, Julie E.; Brown, Nicholas M.; Török, M. Estée; Parkhill, Julian; Peacock, Sharon J.

    2016-01-01

    Vancomycin-resistant Enterococcus faecalis (VREfs) is an important nosocomial pathogen1,2. We undertook whole genome sequencing of E. faecalis associated with bloodstream infection in the UK and Ireland over more than a decade to determine the population structure and genetic associations with hospital adaptation. Three lineages predominated in the population, two of which (L1 and L2) were nationally distributed, and one (L3) geographically restricted. Genome comparison with a global collection identified that L1 and L3 were also present in the USA, but were genetically distinct. Over 90% of VREfs belonged to L1–L3, with resistance acquired and lost multiple times in L1 and L2, but only once followed by clonal expansion in L3. Putative virulence and antibiotic resistance genes were over-represented in L1, L2 and L3 isolates combined, versus the remainder. Each of the three main lineages contained a mixture of vancomycin-resistant and -susceptible E. faecalis (VSEfs), which has important implications for infection control and antibiotic stewardship. PMID:27213049

  15. Pheromone killing of multidrug-resistant Enterococcus faecalis V583 by native commensal strains.

    PubMed

    Gilmore, Michael S; Rauch, Marcus; Ramsey, Matthew M; Himes, Paul R; Varahan, Sriram; Manson, Janet M; Lebreton, Francois; Hancock, Lynn Ernest

    2015-06-09

    Multidrug-resistant Enterococcus faecalis possess numerous mobile elements that encode virulence and antibiotic resistance traits as well as new metabolic pathways, often constituting over one-quarter of the genome. It was of interest to determine how this large accretion of mobile elements affects competitive growth in the gastrointestinal (GI) tract consortium. We unexpectedly observed that the prototype clinical isolate strain V583 was actively killed by GI tract flora, whereas commensal enterococci flourished. It was found that killing of V583 resulted from lethal cross-talk between accumulated mobile elements and that this cross-talk was induced by a heptapeptide pheromone produced by native E. faecalis present in the fecal consortium. These results highlight two important aspects of the evolution of multidrug-resistant enterococci: (i) the accretion of mobile elements in E. faecalis V583 renders it incompatible with commensal strains, and (ii) because of this incompatibility, multidrug-resistant strains sharing features found in V583 cannot coexist with commensal strains. The accumulation of mobile elements in hospital isolates of enterococci can include those that are inherently incompatible with native flora, highlighting the importance of maintaining commensal populations as means of preventing colonization and subsequent infection by multidrug-resistant strains.

  16. Bactericidal effect of plasma jet with helium flowing through 3% hydrogen peroxide against Enterococcus faecalis.

    PubMed

    Zhou, Xin-Cai; Li, Yu-Lan; Liu, De-Xi; Cao, Ying-Guang; Lu, Xin-Pei

    2016-11-01

    The aim of the present study was to assess the antimicrobial activity of plasma jet with helium (He) flowing through 3% hydrogen peroxide in root canals infected with Enterococcus faecalis. A total of 42 single-rooted anterior teeth were prepared, sterilized, inoculated with an E. faecalis suspension and incubated for 7 days. Next, the teeth were randomly divided into six experimental groups (including groups treated by plasma jet with or without He for different time durations) and one control group treated without plasma. The number of surviving bacteria in each canal was determined by counting the colony forming units (CFU)/ml on nutrient agar plates. The results indicated that statistically significant reduction in CFU/ml (P<0.005) existed for all treatment groups relative to the control group. The greatest reductions in CFU/ml were observed for Group 3 (7.027 log unit reduction) and Group 2 (6.237 log unit reduction), which were treated by plasma jet sterilization with He flowing through 3% hydrogen peroxide for 4 min or for 2 min, respectively. In addition, the reduction in Group 3 was significantly greater compared with that in Group 2 or in the groups treated by plasma jet sterilization without He flowing through 3% hydrogen peroxide for 1, 2 or 4 min. In conclusion, plasma jet with or without He flowing through 3% hydrogen peroxide can effectively sterilized root canals infected with E. faecalis and should be considered as an alternative method for root canal disinfection in endodontic treatments.

  17. Enterococcus faecalis reconfigures its gene regulatory network activation under copper exposure

    PubMed Central

    Latorre, Mauricio; Galloway-Peña, Jessica; Roh, Jung Hyeob; Budinich, Marko; Reyes-Jara, Angélica; Murray, Barbara E.; Maass, Alejandro; González, Mauricio

    2014-01-01

    A gene regulatory network was generated in the bacterium Enterococcus faecalis in order to understand how this organism can activate its expression under different copper concentrations. The topological evaluation of the network showed common patterns described in other organisms. Integrating microarray experiments allowed the identification of sub-networks activated under low (0.05 mM CuSO4) and high (0.5 mM CuSO4) copper concentrations. The analysis indicates the presence of specific functionally activated modules induced by copper, highlighting the regulons LysR, ArgR as global regulators and CopY, Fur and LexA as local regulators. Taking advantage of the fact that E. faecalis presented a homeostatic module isolated, we produced an in vivo intervention removing this system from the cell without affecting the connectivity of the global transcriptional network. This strategy led us to find that this bacterium can reconfigure its gene expression to maintain cellular homeostasis, activating new modules principally related to glucose metabolism and transcriptional processes. Finally, these results position E. faecalis as the organism having the most complete and controllable systemic model of copper homeostasis available to date. PMID:24382465

  18. Genetic Diversity and Antibiotic Resistance of Enterococcus faecalis Isolates from Traditional Korean Fermented Soybean Foods.

    PubMed

    Lee, Jong-Hoon; Shin, Donghun; Lee, Bitnara; Lee, Inhyung; Jeong, Do-Won

    2017-02-24

    Eighty-five Enterococcus faecalis isolates collected from animals (40 isolates), Meju (Korean fermented soybean product; 27 isolates), humans (10 isolates), and various environmental samples (eight isolates) were subjected to multilocus sequence typing (MLST) to identify genetic differences between samples of different origins. MLST analysis resulted in 44 sequence types (STs), and the eBURST algorithm clustered the STs into 21 clonal complexes (CCs) and 17 singletons. The predominant STs, ST695 (21.1%, 18/85) and ST694 (9.4%, 8/85), were singletons, and only contained isolates originating from Meju. None of the STs in the current study belonged to CC2 or CC9, which comprise clinical isolates with high levels of antibiotic resistance. The E. faecalis isolates showed the highest rates of resistance to tetracycline (32.9%), followed by erythromycin (9.4%) and vancomycin (2.4%). All isolates from Meju were sensitive to these three antibiotics. Hence, MLST uncovered genetic diversity within E. faecalis, and clustering of the STs using eBURST revealed a correlation between the genotypes and origins of the isolates.

  19. Pheromone killing of multidrug-resistant Enterococcus faecalis V583 by native commensal strains

    PubMed Central

    Gilmore, Michael S.; Rauch, Marcus; Ramsey, Matthew M.; Himes, Paul R.; Varahan, Sriram; Manson, Janet M.; Lebreton, Francois; Hancock, Lynn Ernest

    2015-01-01

    Multidrug-resistant Enterococcus faecalis possess numerous mobile elements that encode virulence and antibiotic resistance traits as well as new metabolic pathways, often constituting over one-quarter of the genome. It was of interest to determine how this large accretion of mobile elements affects competitive growth in the gastrointestinal (GI) tract consortium. We unexpectedly observed that the prototype clinical isolate strain V583 was actively killed by GI tract flora, whereas commensal enterococci flourished. It was found that killing of V583 resulted from lethal cross-talk between accumulated mobile elements and that this cross-talk was induced by a heptapeptide pheromone produced by native E. faecalis present in the fecal consortium. These results highlight two important aspects of the evolution of multidrug-resistant enterococci: (i) the accretion of mobile elements in E. faecalis V583 renders it incompatible with commensal strains, and (ii) because of this incompatibility, multidrug-resistant strains sharing features found in V583 cannot coexist with commensal strains. The accumulation of mobile elements in hospital isolates of enterococci can include those that are inherently incompatible with native flora, highlighting the importance of maintaining commensal populations as means of preventing colonization and subsequent infection by multidrug-resistant strains. PMID:26039987

  20. Biofilm and planktonic Enterococcus faecalis elicit different responses from host phagocytes in vitro.

    PubMed

    Daw, Kasturee; Baghdayan, Arto S; Awasthi, Shanjana; Shankar, Nathan

    2012-07-01

    Enterococcus faecalis is a commensal organism of the gastrointestinal tract but can also cause serious opportunistic infections. In addition to high levels of antibiotic resistance, the ability to form biofilms on abiotic surfaces and on in-dwelling devices within the host complicates treatment strategies and successful outcomes of antibiotic therapy. Despite rapid advances made in recent years in understanding the genomics and virulence of this organism, much remains to be learned regarding the host response to enterococcal infections. In this study, we investigated the interaction of RAW264.7 macrophages and JAWS II dendritic cells with biofilm and planktonic E. faecalis, in vitro. Specifically, we compared phagocytosis, intracellular survival, secretion of proinflammatory cytokines, and the activation and maturation of phagocytes. Our results revealed that both macrophages and dendritic cells phagocytize biofilm mode cells at levels equal to or better than their planktonic counterparts. Internalized biofilm bacteria showed relatively greater survival at 24 h in macrophages than in dendritic cells and led to slightly higher expression of phagocyte activation markers. Macrophages infected with biofilm cells also secreted lower levels of proinflammatory cytokines studied. Overall, these results suggest that biofilm E. faecalis may be better adapted to overcome host defenses in vivo. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  1. Preliminary study on total protein extraction methods from Enterococcus faecalis biofilm.

    PubMed

    Chen, W; Liang, J; He, Z; Jiang, W

    2016-08-30

    Enterococcus faecalis is the major pathogen of post-endodontic disease and refractory periapical periodontitis, and recent research on this species has focused on its pathogenicity. E. faecalis most often causes disease in the form of a biofilm, and total protein expression shows a strong association with its virulence. Therefore, the purpose of our study was to explore different methods of extracting the total proteins of the E. faecalis (ATCC 33186 standard strain) biofilm. The total proteins in the biofilm were extracted using an ultrasonication method with varied parameters, including duration, amplitude setting, period, and duty cycle. After the optimal conditions of ultrasonication were determined based on the protein profile from sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis, the total protein content in the biofilm was detected using the bicinchoninic acid assay, Bradford Coomassie brilliant blue assay, and Lowry assay, and the results were compared and analyzed. The parameters for the optimal conditions of ultrasonication were as follows: a processing duration of 2 min, amplitude setting of 20%, and ultrasonication period of 4 s at a 50% duty cycle. The total protein content was 2299.1 mg/dish when measured by the bicinchoninic assay, 3793.8 mg/dish when measured by the Bradford Coomassie brilliant blue assay, and 1858.0 mg/dish when measured by the Lowry assay. These results demonstrate that the Bradford Coomassie brilliant blue assay is a simple and feasible method for use in detecting the total protein content in a bacterial biofilm.

  2. Antibacterial Efficacy of Neem (Azadirachta indica) Extract against Enterococcus faecalis: An in vitro Study.

    PubMed

    Mustafa, Mohammed

    2016-10-01

    Debridement and disinfection of the root canal is a crucial step in the success of endodontic treatment. Several antimicrobial agents alone or in combination are used to achieve this. The objective of this in vitro study was to assess the antimicrobial efficacy of neem (Azadirachta indica) extract against Enterococcus faecalis. Neem leaf extract, 2% chlorhexidine, 3% sodium hypochlorite were used to assess the antimicrobial efficiency. Agar well diffusion test was used to study the antimicrobial efficacy with saline as control. The zone of inhibition was recorded, tabulated, and analyzed statistically with the help of IBM Statistical Package for the Social Sciences statistics version 20 using analysis of variance test. All the three medicaments showed well-defined and comparable zones of inhibition around their respective wells. All values were significantly higher than the control group. Analysis of variance showed significant difference between zone diameters of chlorhexidine, neem leaf extract, and 3% sodium hypochlorite against E. faecalis (p < 0.05). From the present study, it can be concluded that neem leaf extract shows comparable zones of inhibition with that of chlorhexidine and sodium hypochlorite. Neem leaf extract has significant antimicrobial activity against E. faecalis and thus opens the perspectives for the use of neem extract as an intracanal medication.

  3. How proteases from Enterococcus faecalis contribute to its resistance to short α-helical antimicrobial peptides.

    PubMed

    Nešuta, Ondrej; Budešínský, Miloš; Hadravová, Romana; Monincová, Lenka; Humpolicková, Jana; Cerovský, Václav

    2017-09-29

    HYL-20 (GILSSLWKKLKKIIAK-NH2) is an analogue of a natural antimicrobial peptide (AMP) previously isolated from the venom of wild bee. We examined its antimicrobial activity against three strains of Enterococcus faecalis while focusing on its susceptibility to proteolytic degradation by two known proteases-gelatinase (GelE) and serine protease (SprE)-which are secreted by these bacterial strains. We found that HYL-20 was primarily deamidated at its C-terminal which made the peptide susceptible to consecutive intramolecular cleavage by GelE. Further study utilising 1,10-phenanthroline, a specific GelE inhibitor and analogous peptide with D-Lys at its C-terminus (HYL-20k) revealed that the C-terminal deamidation of HYL-20 is attributed to not yet unidentified protease which also cleaves internal peptide bonds of AMPs. In contrast to published data, participation of SprE in the protective mechanism of E. faecalis against AMPs was not proved. The resistance of HYL-20k to C-terminal deamidation and subsequent intramolecular cleavage has resulted in increased antimicrobial activity against E. faecalis grown in planktonic and biofilm form when compared to HYL-20. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  4. Genome-based characterization of hospital-adapted Enterococcus faecalis lineages.

    PubMed

    Raven, Kathy E; Reuter, Sandra; Gouliouris, Theodore; Reynolds, Rosy; Russell, Julie E; Brown, Nicholas M; Török, M Estée; Parkhill, Julian; Peacock, Sharon J

    2016-02-08

    Vancomycin-resistant Enterococcus faecalis (VREfs) is an important nosocomial pathogen(1,2). We undertook whole genome sequencing of E. faecalis associated with bloodstream infection in the UK and Ireland over more than a decade to determine the population structure and genetic associations with hospital adaptation. Three lineages predominated in the population, two of which (L1 and L2) were nationally distributed, and one (L3) geographically restricted. Genome comparison with a global collection identified that L1 and L3 were also present in the USA, but were genetically distinct. Over 90% of VREfs belonged to L1-L3, with resistance acquired and lost multiple times in L1 and L2, but only once followed by clonal expansion in L3. Putative virulence and antibiotic resistance genes were over-represented in L1, L2 and L3 isolates combined, versus the remainder. Each of the three main lineages contained a mixture of vancomycin-resistant and -susceptible E. faecalis (VSEfs), which has important implications for infection control and antibiotic stewardship.

  5. Genome-based characterization of hospital-adapted Enterococcus faecalis lineages.

    PubMed

    Raven, Kathy E; Reuter, Sandra; Gouliouris, Theodore; Reynolds, Rosy; Russell, Julie E; Brown, Nicholas M; Török, M Estée; Parkhill, Julian; Peacock, Sharon J

    2016-03-01

    Vancomycin-resistant Enterococcus faecalis (VREfs) is an important nosocomial pathogen1,2. We undertook whole genome sequencing of E. faecalis associated with bloodstream infection in the UK and Ireland over more than a decade to determine the population structure and genetic associations with hospital adaptation. Three lineages predominated in the population, two of which (L1 and L2) were nationally distributed, and one (L3) geographically restricted. Genome comparison with a global collection identified that L1 and L3 were also present in the USA, but were genetically distinct. Over 90% of VREfs belonged to L1-L3, with resistance acquired and lost multiple times in L1 and L2, but only once followed by clonal expansion in L3. Putative virulence and antibiotic resistance genes were over-represented in L1, L2 and L3 isolates combined, versus the remainder. Each of the three main lineages contained a mixture of vancomycin-resistant and -susceptible E. faecalis (VSEfs), which has important implications for infection control and antibiotic stewardship.

  6. Inhibition of initial adhesion of uropathogenic Enterococcus faecalis by biosurfactants from Lactobacillus isolates.

    PubMed Central

    Velraeds, M M; van der Mei, H C; Reid, G; Busscher, H J

    1996-01-01

    In this study, 15 Lactobacillus isolates were found to produce biosurfactants in the mid-exponential and stationary growth phases. The stationary-phase biosurfactants from lactobacillus casei subsp. rhamnosus 36 and ATCC 7469, Lactobacillus fermentum B54, and Lactobacillus acidophilus RC14 were investigated further to determine their capacity to inhibit the initial adhesion of uropathogenic Enterococcus faecalis 1131 to glass in a parallel-plate flow chamber. The initial deposition rate of E. faecalis to glass with an adsorbed biosurfactant layer from L. acidophilus RC14 or L. fermentum B54 was significantly decreased by approximately 70%, while the number of adhering enterococci after 4 h of adhesion was reduced by an average of 77%. The surface activity of the biosurfactants and their activity inhibiting the initial adhesion of E. faecalis 1131 were retained after dialysis (molecular weight cutoff, 6,000 to 8,000) and freeze-drying. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy revealed that the freeze-dried biosurfactants from L. acidophilus RC14 and L. fermentum B54 were richest in protein, while those from L. casei subsp. rhamnosus 36 and ATCC 7469 had relatively high polysaccharide and phosphate contents. PMID:8787394

  7. Transcriptome profiling of TDC cluster deletion mutant of Enterococcus faecalis V583.

    PubMed

    Perez, Marta; Ladero, Victor; Del Rio, Beatriz; Redruello, Begoña; de Jong, Anne; Kuipers, Oscar P; Kok, Jan; Martin, M Cruz; Fernandez, Maria; Alvarez, Miguel A

    2016-09-01

    The species Enterococcus faecalis is able to catabolise the amino acid tyrosine into the biogenic amine tyramine by the tyrosine decarboxilase (TDC) pathway Ladero et al. (2012) [1]. The TDC cluster comprises four genes: tyrS, an aminoacyl-tRNA synthetase-like gene; tdcA, which encodes the tyrosine decarboxylase; tyrP, a tyrosine/tyramine exchanger gene and nhaC-2, which encodes an Na(+)/H(+) antiporter and whose role in the tyramine biosynthesis remains unknown [2]. In E. faecalis V583 the last three genes are co-transcribed as a single polycistronic mRNA forming the catabolic operon, while tyrS is transcribed independently of the catabolic genes as a monocistronic mRNA [2]. The catabolic operon is transcriptionally induced by tyrosine and acidic pH. On the opposite, the tyrS expression is repressed by tyrosine concentrations [2]. In this work we report the transcriptional profiling of the TDC cluster deletion mutant (E. faecalis V583 ΔTDC) [2] compared to the wild-type strain, both grown in M17 medium supplemented with tyrosine. The transcriptional profile data of TDC cluster-regulated genes were deposited in the Gene Expression Omnibus (GEO) database under accession no. GSE77864.

  8. Crystal structure of an aerobic FMN-dependent azoreductase (AzoA) from Enterococcus faecalis.

    PubMed

    Liu, Zhi-Jie; Chen, Huizhong; Shaw, Neil; Hopper, Sherryll L; Chen, Lirong; Chen, Siwei; Cerniglia, Carl E; Wang, Bi-Cheng

    2007-07-01

    The initial critical step of reduction of the azo bond during the metabolism of azo dyes is catalyzed by a group of NAD(P)H dependant enzymes called azoreductases. Although several azoreductases have been identified from microorganisms and partially characterized, very little is known about the structural basis for substrate specificity and the nature of catalysis. Enterococcus faecalis azoreductase A (AzoA) is a highly active azoreductase with a broad spectrum of substrate specificity and is capable of degrading a wide variety of azo dyes. Here, we report the crystal structure of the AzoA from E. faecalis determined at 2.07 A resolution with bound FMN ligand. Phases were obtained by single wavelength anomalous scattering of selenomethionine labeled protein crystals. The asymmetric unit consisted of two dimers with one FMN molecule bound to each monomer. The AzoA monomer takes a typical NAD(P)-binding Rossmann fold with a highly conserved FMN binding pocket. A salt bridge between Arg18 and Asp184 restricts the size of the flavin binding pocket such that only FMN can bind. A putative NADH binding site could be identified and a plausible mechanism for substrate reduction is proposed. Expression studies revealed azoA gene to be expressed constitutively in E. faecalis.

  9. Antimicrobial activity of tetraacetylethylenediamine-sodium perborate versus sodium hypochlorite against Enterococcus faecalis

    PubMed Central

    Shakouie, Sahar; Salem Milani, Amin; Eskandarnejad, Mahsa; Rahimi, Saeed; Froughreyhani, Mohammad; Galedar, Saeede; Ranjbar, Ehsan

    2016-01-01

    Background. This study evaluated the antimicrobial activity of Tetraacetylethylenediamine-sodium perborate (TAED-SP) in comparison to 2.5% and 5% sodium hypochlorite (NaOCl) against Enterococcus faecalis. Methods. A standard suspension of E. faecalis was inoculated on 60 plates containing Mueller-Hinton agar culture medium. Four sterile disks of Beckman filtration paper were placed on each plate. TAED-SP, 5% and 2.5% NaOCl were placed on three disks. Sterile physiologic saline was placed on the fourth disk as negative control. After 24-hour incubation, the diameter of the inhibition zone around the disks was measured using a transparent ruler. One-way Analysis of Variance (ANOVA) was used to compare the mean zone of microbial growth in the groups. P-values less than 0.05 were considered statistically significant. Results. There was a significant difference in the diameter of the inhibition zones between groups (P < 0.05). The Tukey post hoc test showed a higher diameter of the inhibitory zone with TAED-SP than that of 2.5% NaOCl. However, there were no significant differences between the inhibitory zones of TAED-SP and 5% NaOCl. Conclusion. TAED-SP and 5% NaOCl have similar antibacterial activity against E. faecalis; however, TAED-SP has a greater antibacterial effect compared to 2.5% NaOCl. PMID:27092214

  10. Bactericidal effect of the 908 nm diode laser on Enterococcus faecalis in infected root canals

    PubMed Central

    Preethee, Thomas; Kandaswamy, Deivanayagam; Arathi, Ganesh; Hannah, Rosaline

    2012-01-01

    Aim: The aim of this study is to evaluate the bactericidal effect of 908 nm diode laser in conjunction with various irrigation regimes in disinfection of apical third of root dentin. Materials and Methods: Sixty prepared teeth with single canals were contaminated with Enterococcus faecalis. The specimens were divided into 6 groups (n = 10): Group 1 and 3 and 5 were subjected to chemo-mechanical preparation using 5.25% sodium hypochlorite (NaOCl), 17% Ethylenediaminetetraacetic acid (EDTA); 1.3% NaOCl, MTAD (mixture of doxycycline, citric acid and a detergent (Tween 80); and, 8.5% saline, respectively followed by 908 nm diode laser irradiation; Group 2 and 4, followed the same procedure as Group1 and 3, however without laser irradiation; and, Group 6, rinsed with saline solution (control). Dentin shavings from apical third were analyzed for the presence of E. faecalis using culture method and Polymerase Chain reaction (PCR). Results: One-way Analysis of variance showed statistically significant differences between the laser irradiated groups, non irradiated groups and the control group. Conclusion: 908 nm diode used in conjunction with conventional chemomechanical techniques demonstrated a significant elimination of E. faecalis in the apical third of root dentin. PMID:22368335

  11. Antimicrobial Activity of Three Root Canal Irrigants on Enterococcus Faecalis: An in Vitro Study

    PubMed Central

    Ahangari, Zohreh; Samiee, Mohammad; Yolmeh, Mohammad Amin; Eslami, Gita

    2008-01-01

    INTRODUCTION: The aim of this study was to compare the antimicrobial effects of 2.5% Sodium hypochlorite (NaOCl), 2% Chlorhexidine Gluconate (CHX) and BioPure MTAD (MTAD) on Enterococcus (E) faecalis-contaminated root canals of human extracted teeth. MATERIALS AND METHODS: Seventy human intact extracted single-rooted teeth with straight root canal randomly divided into 5 groups: positive control (n=5), negative control (n=5), 2.5% NaOCl (n=20), 2% CHX (n=20), and MTAD (n=20). Each tooth was instrumented using the passive step-back technique hand and rotary instruments. E. faecalis incubated into the canals and grew for 4 weeks. Canals irrigated using three mentioned solutions for 5 minutes. Samples were taken from canal walls and transferred into Brain Heart Infusion (BHI) culture medium and placed in an incubator at 37ºC for 96 hours and bacteriological evaluations were done. Chi- Square test and SPSS software were used for the statistical analysis of the results. RESULTS: Bacterial growth was seen in only one sample of MTAD group (5%), but in 4 of CHX group (20%) and 5 of NaOCl group (25%). Chi-Square test showed no statistically difference between groups. CONCLUSION: Based on the results of this study, it seems that all three solutions have acceptable antimicrobial effect on E. faecalis. PMID:24171016

  12. Implication of hypR in the virulence and oxidative stress response of Enterococcus faecalis.

    PubMed

    Verneuil, Nicolas; Rincé, Alain; Sanguinetti, Maurizio; Auffray, Yanick; Hartke, Axel; Giard, Jean-Christophe

    2005-11-01

    HypR has recently been described as the first transcriptional regulator involved in the oxidative stress response and in the intracellular survival of Enterococcus faecalis within macrophages. In order to characterize the HypR regulon, real-time quantitative RT-PCR experiments were performed. The expression of four genes involved in the oxidative stress response encoding catalase, glutathione reductase, and the two subunits of alkyl hydroperoxide reductase were down regulated in the hypR background under H(2)O(2) condition. These findings show that HypR acts as a transcriptional activator, especially during oxidative stress. In addition, DNAse I footprinting assays allowed us to identify the HypR-protected DNA regions corresponding to the "HypR box" in the hypR promoter. Moreover, the effect of the hypR mutation on the virulence of E. faecalis was evaluated in comparison with the wild-type JH2-2 strain using a mouse peritonitis model. Our results revealed that HypR appears to be an important virulence factor in E. faecalis.

  13. Comparison of the bile salts and sodium dodecyl sulfate stress responses in Enterococcus faecalis.

    PubMed Central

    Flahaut, S; Frere, J; Boutibonnes, P; Auffray, Y

    1996-01-01

    The resistance to detergents and detergent-induced tolerance of a gastrointestinal organism, Enterococcus faecalis ATCC 19433, were examined. The most remarkable observation was the rapid response of cells in contact with bile salts and sodium dodecyl sulfate (SDS). The killing by high concentrations of detergents was nearly instantaneous. A 5-s adaptation with moderate sublethal concentrations of bile salts or SDS (0.08 or 0.01%, respectively) was sufficient to induce significant adaptation against homologous lethal conditions (0.3% bile salts or 0.017% SDS). However, resistance to a subsequent lethal challenge progressively increased further to a maximum reached after 30 min of adaptation. Furthermore, extremely strong cross-resistances were observed with bile salts- and SDS-adapted cells. However, no relationship seems to exist between levels of tolerance and de novo-synthesized proteins, since blockage of protein synthesis during adaptation had no effect on induction of resistance to bile salts and SDS. We conclude that this induced tolerance to detergent stress is independent of protein synthesis. Nevertheless, the stress-induced protein patterns of E. faecalis ATCC 19433 showed significant modifications. The rates of synthesis of 45 and 34 proteins were enhanced after treatments with bile salts and SDS, respectively. In spite of the overlap of 12 polypeptides, the protein profiles induced by the two detergents were different, suggesting that these detergents trigger different responses in E. faecalis. Therefore, bile salts cannot be substituted for SDS in biochemical detergent shock experiments with bacteria. PMID:8779581

  14. Antimicrobial activity of tetraacetylethylenediamine-sodium perborate versus sodium hypochlorite against Enterococcus faecalis.

    PubMed

    Shakouie, Sahar; Salem Milani, Amin; Eskandarnejad, Mahsa; Rahimi, Saeed; Froughreyhani, Mohammad; Galedar, Saeede; Ranjbar, Ehsan

    2016-01-01

    Background. This study evaluated the antimicrobial activity of Tetraacetylethylenediamine-sodium perborate (TAED-SP) in comparison to 2.5% and 5% sodium hypochlorite (NaOCl) against Enterococcus faecalis. Methods. A standard suspension of E. faecalis was inoculated on 60 plates containing Mueller-Hinton agar culture medium. Four sterile disks of Beckman filtration paper were placed on each plate. TAED-SP, 5% and 2.5% NaOCl were placed on three disks. Sterile physiologic saline was placed on the fourth disk as negative control. After 24-hour incubation, the diameter of the inhibition zone around the disks was measured using a transparent ruler. One-way Analysis of Variance (ANOVA) was used to compare the mean zone of microbial growth in the groups. P-values less than 0.05 were considered statistically significant. Results. There was a significant difference in the diameter of the inhibition zones between groups (P < 0.05). The Tukey post hoc test showed a higher diameter of the inhibitory zone with TAED-SP than that of 2.5% NaOCl. However, there were no significant differences between the inhibitory zones of TAED-SP and 5% NaOCl. Conclusion. TAED-SP and 5% NaOCl have similar antibacterial activity against E. faecalis; however, TAED-SP has a greater antibacterial effect compared to 2.5% NaOCl.

  15. Investigation of mechanisms and molecular epidemiology of linezolid nonsusceptible Enterococcus faecalis isolated from a teaching hospital in China.

    PubMed

    Li, Bin; Ma, Chuan-Ling; Yu, Xiao; Sun, Yao; Li, Mei-Mei; Ye, Jian-Zhong; Zhang, Ya-Pei; Wu, Qing; Zhou, Tie-Li

    2016-08-01

    The epidemiological and molecular characteristics of eight linezolid nonsusceptible Enterococcus faecalis isolated from a teaching hospital in China (January to July 2014) were investigated. The target site modifications and cfr gene associated with linezolid resistance were not found. Results of the epidemiological investigation indicated that linezolid resistance possibly occurred on several independent occasions and was often not related to linezolid administration.

  16. Draft Genome Sequence of the Bacteriocinogenic Strain Enterococcus faecalis DBH18, Isolated from Mallard Ducks (Anas platyrhynchos)

    PubMed Central

    Arbulu, Sara; Jimenez, Juan J.; Borrero, Juan; Sánchez, Jorge; Frantzen, Cyril; Herranz, Carmen; Nes, Ingolf F.; Cintas, Luis M.; Diep, Dzung B.

    2016-01-01

    Here, we report the draft genome sequence of Enterococcus faecalis DBH18, a bacteriocinogenic lactic acid bacterium (LAB) isolated from mallard ducks (Anas platyrhynchos). The assembly contains 2,836,724 bp, with a G+C content of 37.6%. The genome is predicted to contain 2,654 coding DNA sequences (CDSs) and 50 RNAs. PMID:27417838

  17. Expression of Alzheimer-Type Neurofibrillary Epitopes in Primary Rat Cortical Neurons Following Infection with Enterococcus faecalis.

    PubMed

    Underly, Robert; Song, Mee-Sook; Dunbar, Gary L; Weaver, Charles L

    2015-01-01

    The neurofibrillary tau pathology and amyloid deposits seen in Alzheimer's disease (AD) also have been seen in bacteria-infected brains. However, few studies have examined the role of these bacteria in the generation of tau pathology. One suggested link between infection and AD is edentulism, the complete loss of teeth. Edentulism can result from chronic periodontal disease due to infection by Enterococcus faecalis. The current study assessed the ability to generate early Alzheimer-like neurofibrillary epitopes in primary rat cortical neurons through bacterial infection by E. faecalis. Seven-day old cultured neurons were infected with E. faecalis for 24 and 48 h. An upward molecular weight shift in tau by Western blotting (WB) and increased appearance of tau reactivity in cell bodies and degenerating neurites was found in the 48 h infection group for the antibody CP13 (phospho-Serine 202). A substantial increase in reactivity of Alz-50 was seen at 24 and 48 h after infection. Furthermore, extensive microtubule-associated protein 2 (MAP2) reactivity also was seen at 24 and 48 h post-infection. Our preliminary findings suggest a potential link between E. faecalis infection and intracellular changes that may help facilitate early AD-like neurofibrillary pathology. HighlightsEnterococcus faecalis used in the generation of AD neurofibrillary epitopes in rat.Infection increases Alz-50, phospho-Serine 202 tau, and MAP2 expression.Infection by Enterococcus may play a role in early Alzheimer neurofibrillary changes.

  18. Expression of Alzheimer-Type Neurofibrillary Epitopes in Primary Rat Cortical Neurons Following Infection with Enterococcus faecalis

    PubMed Central

    Underly, Robert; Song, Mee-Sook; Dunbar, Gary L.; Weaver, Charles L.

    2016-01-01

    The neurofibrillary tau pathology and amyloid deposits seen in Alzheimer’s disease (AD) also have been seen in bacteria-infected brains. However, few studies have examined the role of these bacteria in the generation of tau pathology. One suggested link between infection and AD is edentulism, the complete loss of teeth. Edentulism can result from chronic periodontal disease due to infection by Enterococcus faecalis. The current study assessed the ability to generate early Alzheimer-like neurofibrillary epitopes in primary rat cortical neurons through bacterial infection by E. faecalis. Seven-day old cultured neurons were infected with E. faecalis for 24 and 48 h. An upward molecular weight shift in tau by Western blotting (WB) and increased appearance of tau reactivity in cell bodies and degenerating neurites was found in the 48 h infection group for the antibody CP13 (phospho-Serine 202). A substantial increase in reactivity of Alz-50 was seen at 24 and 48 h after infection. Furthermore, extensive microtubule-associated protein 2 (MAP2) reactivity also was seen at 24 and 48 h post-infection. Our preliminary findings suggest a potential link between E. faecalis infection and intracellular changes that may help facilitate early AD-like neurofibrillary pathology. HighlightsEnterococcus faecalis used in the generation of AD neurofibrillary epitopes in rat.Infection increases Alz-50, phospho-Serine 202 tau, and MAP2 expression.Infection by Enterococcus may play a role in early Alzheimer neurofibrillary changes. PMID:26834627

  19. Chitosan-propolis nanoparticle formulation demonstrates anti-bacterial activity against Enterococcus faecalis biofilms

    PubMed Central

    Ong, Teik Hwa; Chitra, Ebenezer; Ramamurthy, Srinivasan; Siddalingam, Rajinikanth Paruvathanahalli; Yuen, Kah Hay; Ambu, Stephen Periathamby

    2017-01-01

    Propolis obtained from bee hives is a natural substance with antimicrobial properties. It is limited by its insolubility in aqueous solutions; hence ethanol and ethyl acetate extracts of Malaysian propolis were prepared. Both the extracts displayed antimicrobial and anti-biofilm properties against Enterococcus faecalis, a common bacterium associated with hospital-acquired infections. High performance liquid chromatography (HPLC) analysis of propolis revealed the presence of flavonoids like kaempferol and pinocembrin. This study investigated the role of propolis developed into nanoparticles with chitosan for its antimicrobial and anti-biofilm properties against E. faecalis. Bacteria that grow in a slimy layer of biofilm are resistant to penetration by antibacterial agents. The use of nanoparticles in medicine has received attention recently due to better bioavailability, enhanced penetrative capacity and improved efficacy. A chitosan-propolis nanoformulation was chosen based on ideal physicochemical properties such as particle size, zeta potential, polydispersity index, encapsulation efficiency and the rate of release of the active ingredients. This formulation inhibited E. faecalis biofilm formation and reduced the number of bacteria in the biofilm by ~90% at 200 μg/ml concentration. When tested on pre-formed biofilms, the formulation reduced bacterial number in the biofilm by ~40% and ~75% at 200 and 300 μg/ml, respectively. The formulation not only reduced bacterial numbers, but also physically disrupted the biofilm structure as observed by scanning electron microscopy. Treatment of biofilms with chitosan-propolis nanoparticles altered the expression of biofilm-associated genes in E. faecalis. The results of this study revealed that chitosan-propolis nanoformulation can be deemed as a potential anti-biofilm agent in resisting infections involving biofilm formation like chronic wounds and surgical site infections. PMID:28362873

  20. The effect of different root canal medicaments on the elimination of Enterococcus faecalis ex vivo

    PubMed Central

    Dammaschke, Till; Jung, Nina; Harks, Inga; Schafer, Edgar

    2013-01-01

    Objective: The aim of this study was to evaluate the antimicrobial effect of chlorhexidine gel (CHX-G) 2%, chlorhexidine powder (CHX-P) 1%, povidone-iodine (PVP-I), polyhexanide and camphorated-and-mentholated chlorophenol (ChKM) ex vivo. Materials and Methods: For every medicament group 10 root segments (15 mm long) of extracted human teeth were prepared to ISO-size 45 and sterilized (n = 50). The root segments were then inoculated with Enterococcus faecalis and aerobically incubated at 37°C. After 1 week, ten root canals were filled with one of the medicaments, respectively and aerobically incubated at 37°C for another week. Ten teeth served as positive controls and were filled with sterile saline solution. After 7 days, the medicaments were inactivated and all root canals were instrumented to ISO-size 50. The obtained dentin samples were dispersed in Ringer solution followed by the preparation of serial dilutions. 10 μl per sample were applied to an agar plate and incubated at 37°C for 48 h. The colony forming units were counted and the reduction factors (RFs) were calculated and statistically analyzed. Results: Compared with the positive controls all medicaments exhibited an antibacterial effect against E. faecalis. The RFs for CHX-G, CHX-P and ChKM were significantly higher compared to PVP-I and polyhexanide (P < 0.05). In contrast to PVP-I and polyhexanide, CHX-G, CHX-P and ChKM were able to eliminate E. faecalis from all dentin samples. Conclusions: Within the limitations of this ex vivo investigation, 2% CHX-G and CHX-P were as effective as ChKM against E. faecalis. Thus, when choosing a root canal medicament the better biocompatibility of CHX compared with ChKM should be taken in consideration. PMID:24932119

  1. Chitosan-propolis nanoparticle formulation demonstrates anti-bacterial activity against Enterococcus faecalis biofilms.

    PubMed

    Ong, Teik Hwa; Chitra, Ebenezer; Ramamurthy, Srinivasan; Siddalingam, Rajinikanth Paruvathanahalli; Yuen, Kah Hay; Ambu, Stephen Periathamby; Davamani, Fabian

    2017-01-01

    Propolis obtained from bee hives is a natural substance with antimicrobial properties. It is limited by its insolubility in aqueous solutions; hence ethanol and ethyl acetate extracts of Malaysian propolis were prepared. Both the extracts displayed antimicrobial and anti-biofilm properties against Enterococcus faecalis, a common bacterium associated with hospital-acquired infections. High performance liquid chromatography (HPLC) analysis of propolis revealed the presence of flavonoids like kaempferol and pinocembrin. This study investigated the role of propolis developed into nanoparticles with chitosan for its antimicrobial and anti-biofilm properties against E. faecalis. Bacteria that grow in a slimy layer of biofilm are resistant to penetration by antibacterial agents. The use of nanoparticles in medicine has received attention recently due to better bioavailability, enhanced penetrative capacity and improved efficacy. A chitosan-propolis nanoformulation was chosen based on ideal physicochemical properties such as particle size, zeta potential, polydispersity index, encapsulation efficiency and the rate of release of the active ingredients. This formulation inhibited E. faecalis biofilm formation and reduced the number of bacteria in the biofilm by ~90% at 200 μg/ml concentration. When tested on pre-formed biofilms, the formulation reduced bacterial number in the biofilm by ~40% and ~75% at 200 and 300 μg/ml, respectively. The formulation not only reduced bacterial numbers, but also physically disrupted the biofilm structure as observed by scanning electron microscopy. Treatment of biofilms with chitosan-propolis nanoparticles altered the expression of biofilm-associated genes in E. faecalis. The results of this study revealed that chitosan-propolis nanoformulation can be deemed as a potential anti-biofilm agent in resisting infections involving biofilm formation like chronic wounds and surgical site infections.

  2. The effect of different root canal medicaments on the elimination of Enterococcus faecalis ex vivo.

    PubMed

    Dammaschke, Till; Jung, Nina; Harks, Inga; Schafer, Edgar

    2013-10-01

    The aim of this study was to evaluate the antimicrobial effect of chlorhexidine gel (CHX-G) 2%, chlorhexidine powder (CHX-P) 1%, povidone-iodine (PVP-I), polyhexanide and camphorated-and-mentholated chlorophenol (ChKM) ex vivo. For every medicament group 10 root segments (15 mm long) of extracted human teeth were prepared to ISO-size 45 and sterilized (n = 50). The root segments were then inoculated with Enterococcus faecalis and aerobically incubated at 37°C. After 1 week, ten root canals were filled with one of the medicaments, respectively and aerobically incubated at 37°C for another week. Ten teeth served as positive controls and were filled with sterile saline solution. After 7 days, the medicaments were inactivated and all root canals were instrumented to ISO-size 50. The obtained dentin samples were dispersed in Ringer solution followed by the preparation of serial dilutions. 10 μl per sample were applied to an agar plate and incubated at 37°C for 48 h. The colony forming units were counted and the reduction factors (RFs) were calculated and statistically analyzed. Compared with the positive controls all medicaments exhibited an antibacterial effect against E. faecalis. The RFs for CHX-G, CHX-P and ChKM were significantly higher compared to PVP-I and polyhexanide (P < 0.05). In contrast to PVP-I and polyhexanide, CHX-G, CHX-P and ChKM were able to eliminate E. faecalis from all dentin samples. Within the limitations of this ex vivo investigation, 2% CHX-G and CHX-P were as effective as ChKM against E. faecalis. Thus, when choosing a root canal medicament the better biocompatibility of CHX compared with ChKM should be taken in consideration.

  3. Novel Structural Components Contribute to the High Thermal Stability of Acyl Carrier Protein from Enterococcus faecalis.

    PubMed

    Park, Young-Guen; Jung, Min-Cheol; Song, Heesang; Jeong, Ki-Woong; Bang, Eunjung; Hwang, Geum-Sook; Kim, Yangmee

    2016-01-22

    Enterococcus faecalis is a Gram-positive, commensal bacterium that lives in the gastrointestinal tracts of humans and other mammals. It causes severe infections because of high antibiotic resistance. E. faecalis can endure extremes of temperature and pH. Acyl carrier protein (ACP) is a key element in the biosynthesis of fatty acids responsible for acyl group shuttling and delivery. In this study, to understand the origin of high thermal stabilities of E. faecalis ACP (Ef-ACP), its solution structure was investigated for the first time. CD experiments showed that the melting temperature of Ef-ACP is 78.8 °C, which is much higher than that of Escherichia coli ACP (67.2 °C). The overall structure of Ef-ACP shows the common ACP folding pattern consisting of four α-helices (helix I (residues 3-17), helix II (residues 39-53), helix III (residues 60-64), and helix IV (residues 68-78)) connected by three loops. Unique Ef-ACP structural features include a hydrophobic interaction between Phe(45) in helix II and Phe(18) in the α1α2 loop and a hydrogen bonding between Ser(15) in helix I and Ile(20) in the α1α2 loop, resulting in its high thermal stability. Phe(45)-mediated hydrophobic packing may block acyl chain binding subpocket II entry. Furthermore, Ser(58) in the α2α3 loop in Ef-ACP, which usually constitutes a proline in other ACPs, exhibited slow conformational exchanges, resulting in the movement of the helix III outside the structure to accommodate a longer acyl chain in the acyl binding cavity. These results might provide insights into the development of antibiotics against pathogenic drug-resistant E. faecalis strains.

  4. Antimicrobial effectiveness of intracanal medicaments on Enterococcus faecalis: chlorhexidine versus octenidine.

    PubMed

    de Lucena, J M V M; Decker, E M; Walter, C; Boeira, L S; Löst, C; Weiger, R

    2013-01-01

    To determine the viability of Enterococcus faecalis in infected human root dentine in vitro after exposure to root canal medicaments based on chlorhexidine and octenidine. Human root segments (n = 40) were infected with E. faecalis for 8 weeks. Root dentine samples (rd) collected at week 4 served as individual baseline values. At week 8, the root segments were randomly divided into four test groups (n = 10 each) for the placement of one of the following medicaments in the root canals: calcium hydroxide paste (CH), chlorhexidine gel (CHX-gel) (5.0%), chlorhexidine/gutta-percha points (CHX-GP) (active points(®) ; Roeko, Langenau, Germany) and octenidine gel (OCT-gel) (5.0%) followed by incubation for 4 weeks. The effect on E. faecalis viability was assessed by two fluorescent dyes (syto 9/propidium iodide) to determine the 'proportion of viable bacteria' (PVB%) and number of 'colony-forming units' (CFU). Mean values and 95% confidence intervals (CI) were calculated for PVB% and log CFU, and the difference between groups was established. Viable and dead bacterial cells were detected in all 'rd' samples at weeks 4 and 8. The treatment with CHX-gel, CHX-GP and OCT-gel resulted in significantly lower PVB% values with 15.4%, 3.5% and 0%, respectively. No growth (CFU) was recorded for these samples at week 12. When medicated by CH, the PVB% was increased without a corresponding change in CFUs. In contrast to calcium hydroxide, both CHX - and octenidine-based intracanal medicaments were effective in decreasing the viability of E. faecalis. OCT showed the most favourable results and may have potential as an endodontic medicament. © 2012 International Endodontic Journal.

  5. A comparison of monomicrobial versus polymicrobial Enterococcus faecalis bacteriuria in a French University Hospital.

    PubMed

    Fourcade, C; Canini, L; Lavigne, J-P; Sotto, A

    2015-08-01

    Enterococci are of considerable relevance in the hospital setting. Their most common location is the urinary tract, where they may be responsible for both colonization and infections. They are often associated with the presence of other microorganisms. The aim was to compare monomicrobial and polymicrobial Enterococcus faecalis bacteriuria. A retrospective study was performed on the demographic, clinical, and laboratory data of 299 patients who had presented with E. faecalis bacteriuria in 2012 at a University Hospital. The bacteriuria was polymicrobial in 46.1 % of cases and in 36.4 % of cases was responsible for a urinary tract infection. Infections appeared to be more prevalent in the polymicrobial than the monomicrobial group (42 % vs 32 %, p = 0.06). Half of the patients who presented with urinary tract colonization received antibiotic treatment (54/ out of 10). A multivariate analysis adjusted for age (adjusted odds ratio [AOR] = 1.02 per year, p = 0.006), gender (AOR = 2.2, p = 0.007), and clinical classification (colonization or infection, AOR = 1.6, p = 0.091), showed that diabetes mellitus (AOR = 2.0, p = 0.04), hospital length of stay exceeding 28 days (AOR = 2.0, p = 0.03), and presence of a urinary catheter (AOR = 2.4, p = 0.001) were all factors associated with polymicrobial E. faecalis bacteriuria. A reduction in the length of hospital stay and the use of urinary catheters would appear to be required to decrease the incidence of urinary tract colonization and infections by polymicrobial E. faecalis. Improper use of antibiotics to treat urinary tract colonization remains a major concern.

  6. Novel Structural Components Contribute to the High Thermal Stability of Acyl Carrier Protein from Enterococcus faecalis*

    PubMed Central

    Park, Young-Guen; Jung, Min-Cheol; Song, Heesang; Jeong, Ki-Woong; Bang, Eunjung; Hwang, Geum-Sook; Kim, Yangmee

    2016-01-01

    Enterococcus faecalis is a Gram-positive, commensal bacterium that lives in the gastrointestinal tracts of humans and other mammals. It causes severe infections because of high antibiotic resistance. E. faecalis can endure extremes of temperature and pH. Acyl carrier protein (ACP) is a key element in the biosynthesis of fatty acids responsible for acyl group shuttling and delivery. In this study, to understand the origin of high thermal stabilities of E. faecalis ACP (Ef-ACP), its solution structure was investigated for the first time. CD experiments showed that the melting temperature of Ef-ACP is 78.8 °C, which is much higher than that of Escherichia coli ACP (67.2 °C). The overall structure of Ef-ACP shows the common ACP folding pattern consisting of four α-helices (helix I (residues 3–17), helix II (residues 39–53), helix III (residues 60–64), and helix IV (residues 68–78)) connected by three loops. Unique Ef-ACP structural features include a hydrophobic interaction between Phe45 in helix II and Phe18 in the α1α2 loop and a hydrogen bonding between Ser15 in helix I and Ile20 in the α1α2 loop, resulting in its high thermal stability. Phe45-mediated hydrophobic packing may block acyl chain binding subpocket II entry. Furthermore, Ser58 in the α2α3 loop in Ef-ACP, which usually constitutes a proline in other ACPs, exhibited slow conformational exchanges, resulting in the movement of the helix III outside the structure to accommodate a longer acyl chain in the acyl binding cavity. These results might provide insights into the development of antibiotics against pathogenic drug-resistant E. faecalis strains. PMID:26631734

  7. Opsonic Antibodies to Enterococcus faecalis Strain 12030 Are Directed against Lipoteichoic Acid

    PubMed Central

    Theilacker, Christian; Kaczynski, Zbigniew; Kropec, Andrea; Fabretti, Francesca; Sange, Tatjana; Holst, Otto; Huebner, Johannes

    2006-01-01

    A teichoic acid (TA)-like polysaccharide in Enterococcus faecalis has previously been shown to induce opsonic antibodies that protect against bacteremia after active and passive immunization. Here we present new data providing a corrected structure of the antigen and the epitope against which the opsonic antibodies are directed. Capsular polysaccharide isolated from E. faecalis strain 12030 by enzymatic digestion of peptidoglycan and chromatography (enzyme-TA) was compared with lipoteichoic acid (LTA) extracted using butanol and purified by hydrophobic-interaction chromatography (BuOH-LTA). Structural determinations were carried out by chemical analysis and nuclear magnetic resonance spectroscopy. Antibody specificity was assessed by enzyme-linked immunosorbent assay and the opsonophagocytosis assay. After alanine ester hydrolysis, there was structural identity between enzyme-TA and BuOH-LTA of the TA-parts of the two molecules. The basic enterococcal LTA structure was confirmed: 1,3-poly(glycerol phosphate) nonstoichiometrically substituted at position C-2 of the glycerol residues with d-Ala and kojibiose. We also detected a novel substituent at position C-2, [d-Ala→6]-α-d-Glcp-(1→2-[d-Ala→6]-α-d-Glcp-1→). Antiserum raised against enzyme-TA bound equally well to BuOH-LTA and dealanylated BuOH-LTA as to the originally described enzyme-TA antigen. BuOH-LTA was a potent inhibitor of opsonophagocytic killing by the antiserum to enzyme-TA. Immunization with antibiotic-killed whole bacterial cells did not induce a significant proportion of antibodies directed against alanylated epitopes on the TA, and opsonic activity was inhibited completely by both alanylated and dealanylated BuOH-LTA. In summary, the E. faecalis strain 12030 enzyme-TA is structurally and immunologically identical to dealanylated LTA. Opsonic antibodies to E. faecalis 12030 are directed predominantly to nonalanylated epitopes on the LTA molecule. PMID:16988246

  8. The Heterodimeric ABC Transporter EfrCD Mediates Multidrug Efflux in Enterococcus faecalis

    PubMed Central

    Hürlimann, Lea M.; Corradi, Valentina; Hohl, Michael; Bloemberg, Guido V.; Tieleman, D. Peter

    2016-01-01

    Nosocomial infections with Enterococcus faecalis are an emerging health problem. However, drug efflux pumps contributing to intrinsic drug resistance are poorly studied in this Gram-positive pathogen. In this study, we functionally investigated seven heterodimeric ABC transporters of E. faecalis that are annotated as drug efflux pumps. Deletion of ef0789-ef0790 on the chromosome of E. faecalis resulted in increased susceptibility to daunorubicin, doxorubicin, ethidium, and Hoechst 33342, and the corresponding transporter was named EfrCD. Unexpectedly, the previously described heterodimeric multidrug ABC transporter EfrAB contributes marginally to drug efflux in the endogenous context of E. faecalis. In contrast, heterologous expression in Lactococcus lactis revealed that EfrAB, EfrCD, and the product of ef2226-ef2227 (EfrEF) mediate the efflux of fluorescent substrates and confer resistance to multiple dyes and drugs, including fluoroquinolones. Four of seven transporters failed to exhibit drug efflux activity for the set of drugs and dyes tested, even upon overexpression in L. lactis. Since all seven transporters were purified as heterodimers after overexpression in L. lactis, a lack of drug efflux activity is not attributed to poor expression or protein aggregation. Reconstitution of the purified multidrug transporters EfrAB, EfrCD, and EfrEF in proteoliposomes revealed functional coupling between ATP hydrolysis and drug binding. Our analysis creates an experimental basis for the accurate prediction of drug efflux transporters and indicates that many annotated multidrug efflux pumps might be incapable of drug transport and thus might fulfill other physiological functions in the cell. PMID:27381387

  9. Association of Metal Homeostasis and (p)ppGpp Regulation in the Pathophysiology of Enterococcus faecalis.

    PubMed

    Colomer-Winter, C; Gaca, A O; Lemos, J A

    2017-07-01

    In Enterococcus faecalis, the regulatory nucleotides pppGpp and ppGpp, collectively, (p)ppGpp, are required for growth in blood, survival within macrophages, and virulence. However, a clear understanding of how (p)ppGpp promotes virulence in E. faecalis and other bacterial pathogens is still lacking. In the host, the essential transition metals iron (Fe) and manganese (Mn) are not readily available to invading pathogens because of a host-driven process called nutritional immunity. Considering its central role in adaptation to nutritional stresses, we hypothesized that (p)ppGpp mediates E. faecalis virulence through regulation of metal homeostasis. Indeed, supplementation of serum with either Fe or Mn restored growth and survival of the Δrel ΔrelQ [(p)ppGpp(0)] strain to wild-type levels. Using a chemically defined medium, we found that (p)ppGpp accumulates in response to either Fe depletion or Mn depletion and that the (p)ppGpp(0) strain has a strong growth requirement for Mn that is alleviated by Fe supplementation. Although inactivation of the nutrient-sensing regulator codY restored some phenotypes of the (p)ppGpp(0) strain, transcriptional analysis showed that the (p)ppGpp/CodY network does not promote transcription of known metal transporters. Interestingly, physiologic and enzymatic investigations suggest that the (p)ppGpp(0) strain requires higher levels of Mn in order to cope with high levels of endogenously produced reactive oxygen species (ROS). Because (p)ppGpp mediates antibiotic persistence and virulence in several bacteria, our findings have broad implications and provide new leads for the development of novel therapeutic and preventive strategies against E. faecalis and beyond. Copyright © 2017 American Society for Microbiology.

  10. Enterococcus faecalis Gene Transfer under Natural Conditions in Municipal Sewage Water Treatment Plants†

    PubMed Central

    Marcinek, Herbert; Wirth, Reinhard; Muscholl-Silberhorn, Albrecht; Gauer, Matthias

    1998-01-01

    The ability of Enterococcus faecalis to transfer various genetic elements under natural conditions was tested in two municipal sewage water treatment plants. Experiments in activated sludge basins of the plants were performed in a microcosm which allowed us to work under sterile conditions; experiments in anoxic sludge digestors were performed in dialysis bags. We used the following naturally occurring genetic elements: pAD1 and pIP1017 (two so-called sex pheromone plasmids with restricted host ranges, which are transferred at high rates under laboratory conditions); pIP501 (a resistance plasmid possessing a broad host range for gram-positive bacteria, which is transferred at low rates under laboratory conditions); and Tn916 (a conjugative transposon which is transferred under laboratory conditions at low rates to gram-positive bacteria and at very low rates to gram-negative bacteria). The transfer rate between different strains of E. faecalis under natural conditions was, compared to that under laboratory conditions, at least 105-fold lower for the sex pheromone plasmids, at least 100-fold lower for pIP501, and at least 10-fold lower for Tn916. In no case was transfer from E. faecalis to another bacterial species detected. By determining the dependence of transfer rates for pIP1017 on bacterial concentration and extrapolating to actual concentrations in the sewage water treatment plant, we calculated that the maximum number of transfer events for the sex pheromone plasmids between different strains of E. faecalis in the municipal sewage water treatment plant of the city of Regensburg ranged from 105 to 108 events per 4 h, indicating that gene transfer should take place under natural conditions. PMID:9464401

  11. Antibacterial Activity of Diode Laser and Sodium Hypochlorite in Enterococcus Faecalis-Contaminated Root Canals.

    PubMed

    Sohrabi, Khosrow; Sooratgar, Aidin; Zolfagharnasab, Kaveh; Kharazifard, Mohammad Javad; Afkhami, Farzaneh

    2016-01-01

    The aim of the present in vitro study was to evaluate the disinfection ability of 980-nm diode laser in comparison with sodium hypochlorite (NaOCl) as a common root canal irrigant in canals infected with Enterococcus faecalis (E. faecalis). The root canals of 18 extracted single-rooted premolars were prepared by rotary system. After decoronation, the roots were autoclaved. One specimen was chosen for the negative control, and the remaining teeth were incubated with E. faecalis suspension for two weeks. Subsequently, one specimen was selected as the positive control and the remaining samples were divided into two groups (n=8). The samples of the first group were irrigated with 5.25% NaOCl and the second group were treated with a 980-nm diode laser. Microbial samples were taken from the root canals and bacterial cultivation was carried out. The average value and the standard deviation of colony-forming units (CFU) of each specimen were measured using descriptive statistics. The student's t-test was used to compare the reduction in CFU in each group. The equality of variance of CFU was measured by the Levene's test. NaOCl resulted in 99.87% removal of the bacteria and showed significantly more antibacterial effect compared to the 980-nm diode laser which led to 96.56% bacterial reduction (P<0.05). Although 5.25% NaOCl seems to reduce E. faecalis more effectively, the diode laser also reduced the bacterial count. Therefore a 980-nm diode laser could be considered as a complementary disinfection method in root canal treatment.

  12. Global Regulation of Gene Expression by the MafR Protein of Enterococcus faecalis

    PubMed Central

    Ruiz-Cruz, Sofía; Espinosa, Manuel; Goldmann, Oliver; Bravo, Alicia

    2016-01-01

    Enterococcus faecalis is a natural inhabitant of the human gastrointestinal tract. However, as an opportunistic pathogen, it is able to colonize other host niches and cause life-threatening infections. Its adaptation to new environments involves global changes in gene expression. The EF3013 gene (here named mafR) of E. faecalis strain V583 encodes a protein (MafR, 482 residues) that has sequence similarity to global response regulators of the Mga/AtxA family. The enterococcal OG1RF genome also encodes the MafR protein (gene OG1RF_12293). In this work, we have identified the promoter of the mafR gene using several in vivo approaches. Moreover, we show that MafR influences positively the transcription of many genes on a genome-wide scale. The most significant target genes encode components of PTS-type membrane transporters, components of ABC-type membrane transporters, and proteins involved in the metabolism of carbon sources. Some of these genes were previously reported to be up-regulated during the growth of E. faecalis in blood and/or in human urine. Furthermore, we show that a mafR deletion mutant strain induces a significant lower degree of inflammation in the peritoneal cavity of mice, suggesting that enterococcal cells deficient in MafR are less virulent. Our work indicates that MafR is a global transcriptional regulator. It might facilitate the adaptation of E. faecalis to particular host niches and, therefore, contribute to its potential virulence. PMID:26793169

  13. Effect of chitosan-ethylenediamine tetraacetic acid on Enterococcus faecalis dentinal biofilm and smear layer removal

    PubMed Central

    Geethapriya, Nagarajan; Subbiya, Arunajatesan; Padmavathy, Kesavaram; Mahalakshmi, Krishnan; Vivekanandan, Paramasivam; Sukumaran, Virudhachalam Ganapathy

    2016-01-01

    Objective: The objective of the study was to evaluate the effectiveness of chitosan and chitosan-ethylenediamine tetraacetic acid (EDTA) (3:1,1:1,1:3) in comparison with 5.2% sodium hypochlorite (NaOCl) in disinfecting Enterococcus faecalis biofilm on root canal dentin and in the removal of smear layer with minimal erosion. Materials and Methods: Seventy single-rooted extracted human mandibular premolars (n = 70) were selected for the study. Forty tooth samples were biomechanically prepared, vertically sectioned, and sterilized by autoclaving. The tooth sections were artificially infected with E. faecalis (ATCC 29212 [n = 35] and clinical isolate [SBEF2, n = 35]) to form mature dentinal biofilm in vitro. The tooth samples were treated with the test solutions: chitosan and chitosan-EDTA (3:1, 1:1, 1:3), and the killing time was determined. The smear layer removal ability of the test solutions (Group A: chitosan-EDTA [1:1], Group B: EDTA, Group C: control) (n = 10 tooth/group) was assessed. Results: Chitosan and chitosan-EDTA (3:1, 1:1, 1:3) exhibited antibacterial activity against both the strains of E. faecalis. Chitosan and chitosan-EDTA caused 3 log reduction in the viable count of the sessile cells of E. faecalis at 15 min while 5.2% NaOCl exhibited 99.98% inhibition at 15 min. Chitosan-EDTA (1:1) was found to be effective in removing the smear layer and showed lesser erosion than EDTA at the coronal and middle portions. Conclusion: Chitosan-EDTA (1:1) is a potential root canal irrigant that performs a dual role – root canal disinfection and smear layer removal. PMID:27656070

  14. Chicken embryo lethality assay for determining the lethal dose and virulence of Enterococcus faecalis.

    PubMed

    Blanco, Ana E; Barz, Martin; Icken, Wiebke; Cavero, David; Sharifi, A Reza; Voss, Matthias; Preisinger, Rudolf; Buxadé, Carlos

    2017-10-01

    Enterococcus faecalis is the major pathogen found in field cases of amyloid arthropathy in chickens. Given the need for a better understanding of the virulence mechanisms of the causative strains, the embryo lethality assay (ELA) is proposed in the present study as a model to evaluate the virulence of E. faecalis strains, specifically the pathogenic avian strain K923/96, which was previously related with amyloid arthropathy. Hence, 0.2 ml of five doses of the cited strain (from 2.5 to 2500 colony-forming units (CFU) per ml) were inoculated into the allantoic cavity of 10-day-old embryos. The embryo mortality rate (EMR) was determined by daily candling of the eggs over a period of seven days and based on this information the median lethal dose (LD50) was calculated. The ELA was repeated four times on a sample of 3443 eggs. The infectious dose showed a significant effect on the EMR. The EMR with the doses of 2.5, 5, 25, 250 and 2500 CFU/ml was 43%, 45%, 63%, 90% and 93%, respectively. The estimated dose at LD50 was 6.6 CFU/ml. As expected, the higher the infectious dose, the greater the EMR and the lower the embryo survival time. The highest EMR was recorded after three and four days post-inoculation in all doses. In conclusion, these results can be used as a basis for further researches on the E. faecalis virulence. In order to corroborate its model capacity to predict the virulence of this bacterium, more ELAs with different E. faecalis strains are required.

  15. High Incidence of Virulence Factors Among Clinical Enterococcus faecalis Isolates in Southwestern Iran

    PubMed Central

    Heidari, Hamid; Hasanpour, Somayeh; Ebrahim-Saraie, Hadi Sedigh

    2017-01-01

    Background Over the past two decades, enterococci have emerged as an important agent responsible for hospital acquired infection. Several virulence factors contribute to the adherence, colonization, evasion of the host immune response, and pathogenicity and severity of the infection. Enterococcus faecalis is the most common and virulent species causing infections in hospitalized patients. The aim of the present study was to examine the prevalence of genes encoding virulence factors and antimicrobial resistance patterns of E. faecalis strains isolated from hospitalized patients in Shiraz, south west of Iran. Materials and Methods A total of 51 E. faecalis isolates from the urine, blood, pleural fluid, peritoneal fluid, eye discharge, endotracheal tube (ETT) and transjugular intrahepatic portosystemic shunt (TIPS) specimens of patients were identified by phenotypic and genotypic methods. Antimicrobial sensitivity tests and detection of virulence factors were performed using standard methods. Results The efa and asa1 were the most frequently detected gene (100%) among the isolates, followed by esp (94.1%), ace (90.2%), gelE (80.4%), cylA (64.7%), and hyl (51%). More than half of the isolates (52.9%) were high level gentamicin resistant (HLGR). Vancomycin resistance was observed among 23 (45.1%) isolates. The lowest antimicrobial activity was related to erythromycin (3.9%), tetracycline (5.9%) and ciprofloxacin (9.8%). No isolate was found resistant to fosfomycin and linezolid. Conclusion Our data indicated a high incidence of virulence factors among E. faecalis strains isolated from clinical samples. Colonization of drug resistant virulent isolates in hospital environment may lead to life threatening infection in hospitalized patients. Therefore, infection control procedures should be performed. PMID:28332345

  16. Virulence Genes among Enterococcus faecalis and Enterococcus faecium Isolated from Coastal Beaches and Human and Nonhuman Sources in Southern California and Puerto Rico

    PubMed Central

    Talavera, Ginamary Negrón; Hernández, Luis A. Ríos; Ambrose, Richard F.; Jay, Jennifer A.

    2016-01-01

    Most Enterococcus faecalis and E. faecium are harmless to humans; however, strains harboring virulence genes, including esp, gelE, cylA, asa1, and hyl, have been associated with human infections. E. faecalis and E. faecium are present in beach waters worldwide, yet little is known about their virulence potential. Here, multiplex PCR was used to compare the distribution of virulence genes among E. faecalis and E. faecium isolated from beaches in Southern California and Puerto Rico to isolates from potential sources including humans, animals, birds, and plants. All five virulence genes were found in E. faecalis and E. faecium from beach water, mostly among E. faecalis. gelE was the most common among isolates from all source types. There was a lower incidence of asa1, esp, cylA, and hyl genes among isolates from beach water, sewage, septage, urban runoff, sea wrack, and eelgrass as compared to human isolates, indicating that virulent strains of E. faecalis and E. faecium may not be widely disseminated at beaches. A higher frequency of asa1 and esp among E. faecalis from dogs and of asa1 among birds (mostly seagull) suggests that further studies on the distribution and virulence potential of strains carrying these genes may be warranted. PMID:27144029

  17. Structural studies of the Enterococcus faecalis SufU [Fe-S] cluster protein

    PubMed Central

    Riboldi, Gustavo P; Verli, Hugo; Frazzon, Jeverson

    2009-01-01

    Background Iron-sulfur clusters are ubiquitous and evolutionarily ancient inorganic prosthetic groups, the biosynthesis of which depends on complex protein machineries. Three distinct assembly systems involved in the maturation of cellular Fe-S proteins have been determined, designated the NIF, ISC and SUF systems. Although well described in several organisms, these machineries are poorly understood in Gram-positive bacteria. Within the Firmicutes phylum, the Enterococcus spp. genus have recently assumed importance in clinical microbiology being considered as emerging pathogens for humans, wherein Enterococcus faecalis represents the major species associated with nosocomial infections. The aim of this study was to carry out a phylogenetic analysis in Enterococcus faecalis V583 and a structural and conformational characterisation of it SufU protein. Results BLAST searches of the Enterococcus genome revealed a series of genes with sequence similarity to the Escherichia coli SUF machinery of [Fe-S] cluster biosynthesis, namely sufB, sufC, sufD and SufS. In addition, the E. coli IscU ortholog SufU was found to be the scaffold protein of Enterococcus spp., containing all features considered essential for its biological activity, including conserved amino acid residues involved in substrate and/or co-factor binding (Cys50,76,138 and Asp52) and, phylogenetic analyses showed a close relationship with orthologues from other Gram-positive bacteria. Molecular dynamics for structural determinations and molecular modeling using E. faecalis SufU primary sequence protein over the PDB:1su0 crystallographic model from Streptococcus pyogenes were carried out with a subsequent 50 ns molecular dynamic trajectory. This presented a stable model, showing secondary structure modifications near the active site and conserved cysteine residues. Molecular modeling using Haemophilus influenzae IscU primary sequence over the PDB:1su0 crystal followed by a MD trajectory was performed to analyse

  18. Interference in Pheromone-Responsive Conjugation of a High-Level Bacitracin Resistant Enterococcus faecalis Plasmid of Poultry Origin

    PubMed Central

    Tremblay, Cindy-Love; Archambault, Marie

    2013-01-01

    The current study reports on contact interference of a high-level bacitracin- resistant pheromone-responsive plasmid of Enterococcus faecalis strain 543 of poultry origin during conjugative transfer of bcr antimicrobial resistance genes using a polyclonal antiserum aggregation substance44–560 (AS). After induction with pheromones produced by the recipient strain E. faecalis JH2-2, clumping of the donor E. faecalis strain 543 was observed as well as high transfer frequencies of bcr in short time broth mating. Filter mating assays from donor strain E. faecalis 543 to the recipient strain E. faecalis JH2-2 revealed conjugative transfer of asa1 (AS), bcrRAB and traB (negative regulator pheromone response) genes. The presence of these genes in transconjugants was confirmed by antimicrobial susceptibility testing, PCR, Southern hybridization and sequencing. A significant reduction in formation of aggregates was observed when the polyclonal anti-AS44–560 was added in the pheromone-responsive conjugation experiments as compared to the induced state. Moreover, interference of anti-AS44–560 antibodies in pheromone-responsive conjugation was demonstrated by a reduction in horizontal transfer of asa1 and bcr genes between E. faecalis strain 543 and E. faecalis JH2-2. Reducing the pheromone-responsive conjugation of E. faecalis is of interest because of its clinical importance in the horizontal transfer of antimicrobial resistance. PMID:24030654

  19. The Capability of Tyramine Production and Correlation between Phenotypic and Genetic Characteristics of Enterococcus faecium and Enterococcus faecalis Strains.

    PubMed

    Bargossi, Eleonora; Gardini, Fausto; Gatto, Veronica; Montanari, Chiara; Torriani, Sandra; Tabanelli, Giulia

    2015-01-01

    The aim of this study was to investigate the diversity of tyramine production capability of four Enterococcus strains in buffered systems in relation to their genetic characteristics and environmental conditions. Cells of the strains Enterococcus faecalis EF37 and ATCC 29212, and E. faecium FC12 and FC643 were re-suspended in phosphate/citrate buffers with different pH, NaCl concentration and incubation temperature. At intervals, cell viability and tyramine production were assessed by plate counting and HPLC analysis, respectively. The activity of a purified tyrosine decarboxylase (TDC) was determined under the same conditions, as a reference. Reduced loss in cell viability was observed in all the tested conditions, except for pH 4 after 24 h. The TDC activity was greatly heterogeneous within the enterococci: EF37 and FC12 produced the higher tyramine concentrations, ATCC 29212 showed a reduced decarboxylase activity, while EF643 did not accumulate detectable amounts of tyramine in all the conditions assayed. Among the considerate variables, temperature was the most influencing factor on tyramine accumulation for enterococcal cells. To further correlate the phenotypic and genetic characteristics of the enterococci, the TDC operon region carrying the genes tyrosine decarboxylase (tyrDC), tyrosine/tyramine permease (tyrP), and Na(+)/H(+) antiporter (nhaC-2) was amplified and sequenced. The genetic organization and nucleotide sequence of this operon region were highly conserved in the enterococcal strains of the same species. The heterogeneity in tyramine production found between the two E. faecalis strains could be ascribed to different regulation mechanisms not yet elucidated. On the contrary, a codon stop was identified in the translated tyrDC sequence of E. faecium FC643, supporting its inability to accumulate tyramine in the tested conditions. In addition, the presence of an additional putative tyrosine decarboxylase with different substrate specificity and

  20. The Capability of Tyramine Production and Correlation between Phenotypic and Genetic Characteristics of Enterococcus faecium and Enterococcus faecalis Strains

    PubMed Central

    Bargossi, Eleonora; Gardini, Fausto; Gatto, Veronica; Montanari, Chiara; Torriani, Sandra; Tabanelli, Giulia

    2015-01-01

    The aim of this study was to investigate the diversity of tyramine production capability of four Enterococcus strains in buffered systems in relation to their genetic characteristics and environmental conditions. Cells of the strains Enterococcus faecalis EF37 and ATCC 29212, and E. faecium FC12 and FC643 were re-suspended in phosphate/citrate buffers with different pH, NaCl concentration and incubation temperature. At intervals, cell viability and tyramine production were assessed by plate counting and HPLC analysis, respectively. The activity of a purified tyrosine decarboxylase (TDC) was determined under the same conditions, as a reference. Reduced loss in cell viability was observed in all the tested conditions, except for pH 4 after 24 h. The TDC activity was greatly heterogeneous within the enterococci: EF37 and FC12 produced the higher tyramine concentrations, ATCC 29212 showed a reduced decarboxylase activity, while EF643 did not accumulate detectable amounts of tyramine in all the conditions assayed. Among the considerate variables, temperature was the most influencing factor on tyramine accumulation for enterococcal cells. To further correlate the phenotypic and genetic characteristics of the enterococci, the TDC operon region carrying the genes tyrosine decarboxylase (tyrDC), tyrosine/tyramine permease (tyrP), and Na+/H+ antiporter (nhaC-2) was amplified and sequenced. The genetic organization and nucleotide sequence of this operon region were highly conserved in the enterococcal strains of the same species. The heterogeneity in tyramine production found between the two E. faecalis strains could be ascribed to different regulation mechanisms not yet elucidated. On the contrary, a codon stop was identified in the translated tyrDC sequence of E. faecium FC643, supporting its inability to accumulate tyramine in the tested conditions. In addition, the presence of an additional putative tyrosine decarboxylase with different substrate specificity and genetic

  1. Effects of Enterococcus faecalis fsr genes on production of gelatinase and a serine protease and virulence.

    PubMed

    Qin, X; Singh, K V; Weinstock, G M; Murray, B E

    2000-05-01

    Three agr-like genes (fsrA, fsrB, and fsrC, for Enterococcus faecalis regulator) were found upstream of the previously reported gelatinase gene (gelE) and a downstream putative serine protease gene (sprE; accession number Z12296) of Enterococcus faecalis OG1RF. The deduced amino acid sequence of fsrA shows 26% identity and 38% similarity to Staphylococcus aureus AgrA (the response regulator of the accessory gene regulator system in the agr locus), FsrB shows 23% identity and 41% similarity to S. aureus AgrB, and FsrC shows 23% identity and 36% similarity to S. aureus AgrC (the sensor transducer of Agr system). Northern blot analysis suggested that gelE and sprE are cotranscribed and that fsrB and fsrC are also cotranscribed in OG1RF. Northern blot analysis of fsrA, fsrB, fsrC, gelE, and sprE insertion mutants showed that fsrB, fsrC, gelE, and sprE are not expressed in fsrA, fsrB, and fsrC mutants, while insertion in an open reading frame further upstream of fsrA did not effect the expression of these genes, suggesting that agr-like genes may be autoregulated and that they regulate gelE and sprE expression, as further confirmed by complementation of fsr gene mutations with a 6-kb fragment which contains all three fsr genes in the shuttle vector, pAT18. Testing of 95 other isolates of E. faecalis showed that 62% produced gelatinase (Gel(+)), while 91% (including all Gel(+) strains) hybridized to a gelE probe; 71% (including all Gel(+) strains) hybridized to an fsr probe, corroborating the conclusion that both gelE and fsr are necessary for gelatinase production. Testing of fsrA, fsrB, and sprE mutants in a mouse peritonitis model showed that sprE and agr-like gene mutants resulted in highly significantly prolonged survival compared to the parent strain OG1RF, a finding similar to what we had previously shown for a gelE mutant. These results suggest that sprE and agr-like genes contribute to the virulence of E. faecalis OG1RF in this model.

  2. Comparison of Enterococcus faecium and Enterococcus faecalis Strains isolated from water and clinical samples: antimicrobial susceptibility and genetic relationships.

    PubMed

    Castillo-Rojas, Gonzalo; Mazari-Hiríart, Marisa; Ponce de León, Sergio; Amieva-Fernández, Rosa I; Agis-Juárez, Raúl A; Huebner, Johannes; López-Vidal, Yolanda

    2013-01-01

    Enterococci are part of the normal intestinal flora in a large number of mammals, and these microbes are currently used as indicators of fecal contamination in water and food for human consumption. These organisms are considered one of the primary causes of nosocomial and environmental infections due to their ability to survive in the environment and to their intrinsic resistance to antimicrobials. The aims of this study were to determine the biochemical patterns and antimicrobial susceptibilities of Enterococcus faecalis and E. faecium isolates from clinical samples and from water (groundwater, water from the Xochimilco wetland, and treated water from the Mexico City Metropolitan Area) and to determine the genetic relationships among these isolates. A total of 121 enterococcus strains were studied; 31 and 90 strains were isolated from clinical samples and water (groundwater, water from the Xochimilco wetland, and water for agricultural irrigation), respectively. Identification to the species level was performed using a multiplex PCR assay, and antimicrobial profiles were obtained using a commercial kit. Twenty-eight strains were analyzed by pulsed-field gel electrophoresis (PFGE). E. faecium strains isolated from water showed an atypical biochemical pattern. The clinical isolates showed higher resistance to antibiotics than those from water. Both the enterococci isolated from humans, and those isolated from water showed high genetic diversity according to the PFGE analysis, although some strains seemed to be closely related. In conclusion, enterococci isolated from humans and water are genetically different. However, water represents a potential route of transmission to the community and a source of antimicrobial resistance genes that may be readily transmitted to other, different bacterial species.

  3. Comparison of Enterococcus faecium and Enterococcus faecalis Strains Isolated from Water and Clinical Samples: Antimicrobial Susceptibility and Genetic Relationships

    PubMed Central

    Castillo-Rojas, Gonzalo; Mazari-Hiríart, Marisa; Ponce de León, Sergio; Amieva-Fernández, Rosa I.; Agis-Juárez, Raúl A.; Huebner, Johannes; López-Vidal, Yolanda

    2013-01-01

    Enterococci are part of the normal intestinal flora in a large number of mammals, and these microbes are currently used as indicators of fecal contamination in water and food for human consumption. These organisms are considered one of the primary causes of nosocomial and environmental infections due to their ability to survive in the environment and to their intrinsic resistance to antimicrobials. The aims of this study were to determine the biochemical patterns and antimicrobial susceptibilities of Enterococcus faecalis and E. faecium isolates from clinical samples and from water (groundwater, water from the Xochimilco wetland, and treated water from the Mexico City Metropolitan Area) and to determine the genetic relationships among these isolates. A total of 121 enterococcus strains were studied; 31 and 90 strains were isolated from clinical samples and water (groundwater, water from the Xochimilco wetland, and water for agricultural irrigation), respectively. Identification to the species level was performed using a multiplex PCR assay, and antimicrobial profiles were obtained using a commercial kit. Twenty-eight strains were analyzed by pulsed-field gel electrophoresis (PFGE). E. faecium strains isolated from water showed an atypical biochemical pattern. The clinical isolates showed higher resistance to antibiotics than those from water. Both the enterococci isolated from humans, and those isolated from water showed high genetic diversity according to the PFGE analysis, although some strains seemed to be closely related. In conclusion, enterococci isolated from humans and water are genetically different. However, water represents a potential route of transmission to the community and a source of antimicrobial resistance genes that may be readily transmitted to other, different bacterial species. PMID:23560050

  4. β-Lactam combinations with daptomycin provide synergy against vancomycin-resistant Enterococcus faecalis and Enterococcus faecium

    PubMed Central

    Smith, Jordan R.; Barber, Katie E.; Raut, Animesh; Aboutaleb, Mostafa; Sakoulas, George; Rybak, Michael J.

    2015-01-01

    Objectives Enterococcus faecalis (Efc) and Enterococcus faecium (Efm) are frequently resistant to vancomycin and β-lactams (BLs). In vitro data suggest synergy between several BLs and glycopeptides or lipopeptides against resistant pathogens. Our objective was to conduct combination MIC and time–kill experiments to evaluate BL synergy with daptomycin against enterococci. Methods Fifteen Efc and 20 Efm strains were evaluated for daptomycin enhancement via combination MICs. Daptomycin MICs were obtained by microdilution in the absence and presence of ceftaroline, ertapenem, cefepime, ceftriaxone, cefotaxime, cefazolin and ampicillin. Two Efc strains (R6981 and R7808) and one isogenic daptomycin-susceptible/daptomycin-non-susceptible Efm pair (8019/5938) were evaluated in time–kill experiments. Daptomycin at 0.5 × MIC was used in combination with BL at biological free concentration. Strain 5938 was evaluated for enhancement of daptomycin binding in fluorescently labelled daptomycin (BoDipy) experiments. Results Ceftaroline reduced daptomycin MIC values the most against all strains. In time–kill experiments, ceftaroline, ertapenem, cefepime, ceftriaxone and ampicillin demonstrated synergy with daptomycin against all strains, cefazolin demonstrated none and cefotaxime demonstrated synergy against only R7808. Bacterial reduction at 24 h was greater for daptomycin + ceftaroline, ertapenem, cefepime, ceftriaxone or ampicillin for all strains compared with any single agent or daptomycin + cefazolin or cefotaxime (P < 0.001). In BoDipy daptomycin experiments, ceftaroline enhanced daptomycin binding most compared with all other agents (P < 0.001). Conclusions The data support the potential use of daptomycin/BL combination therapy in infections caused by VRE. Combination regimens, other than those involving cefazolin and cefotaxime, provide better kill compared with daptomycin alone. Further clinical research involving daptomycin combinations is

  5. Biofilm forming capacity of Enterococcus faecalis on Gutta-percha points treated with four disinfectants using confocal scanning laser microscope: An in vitro study

    PubMed Central

    Ravi Chandra, Polavarapu Venkata; Kumar, Vemisetty Hari; Reddy, Surakanti Jayaprada; Kiran, Dandolu Ram; Krishna, Muppala Nagendra; Kumar, Golla Vinay

    2015-01-01

    Background: The aim of this study was to evaluate and compare the in vitro biofilm forming capacity of Enterococcus faecalis on Gutta-percha points disinfected with four disinfectants. Materials and Methods: A total of 50 Gutta-percha points used in this study were divided into four test groups based on disinfectant (5.25% sodium hypochlorite, 2% chlorhexidine gluconate, 20% neem, 13% benzalkonium chloride [BAK]), and one control group. The Gutta-percha points were initially treated with corresponding disinfectants followed by anaerobic incubation in Brain Heart Infusion broth suspended with human serum and E. faecalis strain for 14 days. After incubation, these Gutta-percha points were stained with Acridine Orange (Sigma – Aldrich Co., St. Louis, MO, USA) and 0.5 mm thick cross section samples were prepared. The biofilm thickness of E. faecalis was analyzed quantitatively using a confocal scanning laser microscope. Results statistically analyzed using analysis of variance. P < 0.05 was considered to be significant. Results: Confocal scanning laser microscope showed reduced amount of E. faecalis biofilm on Gutta-percha points treated with BAK and sodium hypochlorite. Post-hoc (least square differences) test revealed that there is no statistically significant difference between BAK and sodium hypochlorite groups (P > 0.05). Conclusion: This study illustrates that the Gutta-percha points disinfected with sodium hypochlorite and BAK showed minimal biofilm growth on its surface. PMID:26288622

  6. Antimicrobial activity of herbal medicines (tulsi extract, neem extract) and chlorhexidine against Enterococcus faecalis in Endodontics: An in vitro study.

    PubMed

    Chandrappa, Pradeep Muttagadur; Dupper, Akash; Tripathi, Pragya; Arroju, Ramakrishna; Sharma, Preeti; Sulochana, Konthoujam

    2015-12-01

    Successful endodontic treatment depends on effective disinfection and complete sealing of root canal. Various medicaments are advised for disinfecting root canal, such as herbal and non-herbal medicaments. This study was done to assess the antimicrobial activity of herbal medicines (neem extract, tulsi extract) and chlorhexidine against Enterococcus faecalis in Endodontics. Agar diffusion method was used to evaluate the antimicrobial action of different medicines. Sixty samples were segregated into four groups with 15 samples in each: Group I: chlorhexidine 2%, Group II: neem extract, Group III: tulsi extract, and Group IV: distilled water. The inhibition zones against E. faecalis were recorded and statistically assessed using one-way analysis of variance (ANOVA) test (P < 0.05). Significant antibacterial effect against E. faecalis was observed with chlorhexidine followed by neem extract and tulsi extract. Herbal medicines seemed to be effective against E. faecalis compared to 2% chlorhexidine gluconate.

  7. Slime production and antibiotic resistance of Enterococcus faecalis isolated from arthritis in chickens.

    PubMed

    Ciftci, Alper; Findik, Arzu; Iça, Tuba; Bas, Bülent; Onuk, Ertan Emek; Güngördü, Sibel

    2009-06-01

    Slime factor production and antibiotic resistance of 67 Enterococcus faecalis strains isolated from chicken arthritis were investigated in this study. Slime factor productions of enterococci were found as 59.7%. The antibiotic resistances were investigated by testing gentamycin, penicillin, streptomycin, vancomycin, danofloxacin, and enrofloxacin. The resistance rates were found as 62.68%, 76.11%, 67.16%, 13.43%, 47.76%, 43.28%, respectively. For slime factor positive enterococci, the antibiotic resistance rates were found as follows respectively; 82.50%, 87.50%, 92.50%, 17.50%, 72.50%, and 60.00%. In conclusion; the slime factor might play a role as a colonization factor for chicken arthritis and slime factor positive enterococci were found to be more resistant to these antibiotics. The resistance rates between slime factor positive and negative enterococci against the tested antibiotics except for vancomycin were found statistically significant (p<0.05).

  8. Treatment of enterococcus faecalis bacteria by a helium atmospheric cold plasma brush with oxygen addition

    SciTech Connect

    Chen Wei; Huang Jun; Wang Xingquan; Lv Guohua; Zhang Guoping; Du Ning; Liu Xiaodi; Guo Lihong; Yang Size

    2012-07-01

    An atmospheric cold plasma brush suitable for large area and low-temperature plasma-based sterilization is designed. Results demonstrate that the He/O{sub 2} plasma more effectively kills Enterococcus faecalis than the pure He plasma. In addition, the sterilization efficiency values of the He/O{sub 2} plasma depend on the oxygen fraction in Helium gas. The atmospheric cold plasma brush using a proper ratio of He/O{sub 2} (2.5%) reaches the optimum sterilization efficiency. After plasma treatment, the cell structure and morphology changes can be observed by the scanning electron microscopy. Optical emission measurements indicate that reactive species such as O and OH play a significant role in the sterilization process.

  9. Microbial Flora of Root Canals of Pulpally-infected Teeth: Enterococcus faecalis a Prevalent Species

    PubMed Central

    Gajan, Esrafil Balaei; Aghazadeh, Mohammad; Abashov, Rahib; Salem Milani, Amin; Moosavi, Zohreh

    2009-01-01

    Background and aims The aim of this study was to determine the microorganisms prevalent in the necrotic dental pulp and root canals of unsuccessfully treated teeth. Materials and methods The present study was conducted on 150 single-rooted teeth of patients referring to a dental clinic. Sampling was performed by placing a sterile paper point in the canal for 60 s. Bacterial samples were evaluated by a microbiological technique specific for anaerobic species, used for isolation and identification of sampled strains. Results From the 150 samples taken, 101 were from necrotic pulps (primary infection) and 49 were from the teeth with an unsuccessful endodontic treatment (secondary infection). Conclusion Enterococcus faecalis was a prevalent species in the failed root canals evaluated. PMID:23230477

  10. Treatment of enterococcus faecalis bacteria by a helium atmospheric cold plasma brush with oxygen addition

    NASA Astrophysics Data System (ADS)

    Chen, Wei; Huang, Jun; Du, Ning; Liu, Xiao-Di; Wang, Xing-Quan; Lv, Guo-Hua; Zhang, Guo-Ping; Guo, Li-Hong; Yang, Si-Ze

    2012-07-01

    An atmospheric cold plasma brush suitable for large area and low-temperature plasma-based sterilization is designed. Results demonstrate that the He/O2 plasma more effectively kills Enterococcus faecalis than the pure He plasma. In addition, the sterilization efficiency values of the He/O2 plasma depend on the oxygen fraction in Helium gas. The atmospheric cold plasma brush using a proper ratio of He/O2 (2.5%) reaches the optimum sterilization efficiency. After plasma treatment, the cell structure and morphology changes can be observed by the scanning electron microscopy. Optical emission measurements indicate that reactive species such as O and OH play a significant role in the sterilization process.

  11. Serodiversity of Opsonic Antibodies against Enterococcus faecalis —Glycans of the Cell Wall Revisited

    PubMed Central

    Theilacker, Christian; Kaczyński, Zbigniew; Kropec, Andrea; Sava, Irina; Ye, Libin; Bychowska, Anna; Holst, Otto; Huebner, Johannes

    2011-01-01

    In a typing system based on opsonic antibodies against carbohydrate antigens of the cell envelope, 60% of Enterococcus faecalis strains can be assigned to one of four serotypes (CPS-A to CPS-D). The structural basis for enterococcal serotypes, however, is still incompletely understood. Here we demonstrate that antibodies raised against lipoteichoic acid (LTA) from a CPS-A strain are opsonic to both CPS-A and CPS-B strains. LTA-specific antibodies also bind to LTA of CPS-C and CPS-D strains, but fail to opsonize them. From CPS-C and CPS-D strains resistant to opsonization by anti-LTA, we purified a novel diheteroglycan with a repeating unit of →6)-β-Galf-(1→3)- β-D-Glcp-(1→ with O-acetylation in position 5 and lactic acid substitution at position 3 of the Galf residue. The purified diheteroglycan, but not LTA absorbed opsonic antibodies from whole cell antiserum against E. faecalis type 2 (a CPS-C strain) and type 5 (CPS-D). Rabbit antiserum raised against purified diheteroglycan opsonized CPS-C and CPS-D strains and passive protection with diheteroglycan-specific antiserum reduced bacterial counts by 1.4 – 3.4 logs in mice infected with E. faecalis strains of the CPS-C and CPS-D serotype. Diheteroglycan-specific opsonic antibodies were absorbed by whole bacterial cells of E. faecalis FA2-2 (CPS-C) but not by its isogenic acapsular cpsI-mutant and on native PAGE purified diheteroglycan co-migrated with the gene product of the cps-locus, suggesting that it is synthesized by this locus. In summary, two polysaccharide antigens, LTA and a novel diheteroglycan, are targets of opsonic antibodies against typeable E. faecalis strains. These cell-wall associated polymers are promising candidates for active and passive vaccination and add to our armamentarium to fight this important nosocomial pathogen. PMID:21437253

  12. An ABC transporter is required for secretion of peptide sex pheromones in Enterococcus faecalis.

    PubMed

    Varahan, Sriram; Harms, Nathan; Gilmore, Michael S; Tomich, John M; Hancock, Lynn E

    2014-09-23

    Enterococci are leading causes of hospital-acquired infection in the United States and continue to develop resistances to new antibiotics. Many Enterococcus faecalis isolates harbor pheromone-responsive plasmids that mediate horizontal transfer of even large blocks of chromosomal genes, resulting in hospital-adapted strains over a quarter of whose genomes consist of mobile elements. Pheromones to which the donor cells respond derive from lipoprotein signal peptides. Using a novel bacterial killing assay dependent on the presence of sex pheromones, we screened a transposon mutant library for functions that relate to the production and/or activity of the effector pheromone. Here we describe a previously uncharacterized, but well-conserved, ABC transporter that contributes to pheromone production. Using three distinct pheromone-dependent mating systems, we show that mutants defective in expressing this transporter display a 5- to 6-order-of-magnitude reduction in conjugation efficiency. In addition, we demonstrate that the ABC transporter mutant displays an altered biofilm architecture, with a significant reduction in biofilm biomass compared to that of its isogenic parent, suggesting that pheromone activity also influences biofilm development. The conservation of this peptide transporter across the Firmicutes suggests that it may also play an important role in cell-cell communication in other species within this important phylum. Enterococcus faecalis ranks as one of the leading causes of hospital-associated infections. Strains possessing resistance to multiple antibiotics are becoming all too common in clinical settings. Pheromone-responsive plasmids play an important role in harboring and disseminating these antibiotic resistance genes. Here we have identified a novel ABC transporter that is responsible for the secretion of peptide pheromones, which enables communication between cells to mediate plasmid transfer. We have also shown that this transporter is

  13. Glycopeptide susceptibility among Danish Enterococcus faecium and Enterococcus faecalis isolates of animal and human origin and PCR identification of genes within the VanA cluster.

    PubMed Central

    Aarestrup, F M; Ahrens, P; Madsen, M; Pallesen, L V; Poulsen, R L; Westh, H

    1996-01-01

    The MICs of vancomycin and avoparcin were determined for isolates of Enterococcus faecium and isolates of Enterococcus faecalis recovered from the feces of humans and animals in Denmark. Two hundred twenty-one of 376 (59%) isolates of E. faecium and 2 of 133 (1.5%) isolates of E. faecalis were resistant to vancomycin (MICs, 128 to > or = 256 micrograms/ml), and all vancomycin-resistant isolates were resistant to avoparcin (MICs, 64 to > or = 256 micrograms/ml). All vancomycin-resistant isolates examined carried the vanA, vanX, and vanR genes, suggesting that a gene cluster similar to that of the transposon Tn1546 was responsible for the resistance. PMID:8843309

  14. Involvement of Enterococcus faecalis Small RNAs in Stress Response and Virulence

    PubMed Central

    Michaux, Charlotte; Hartke, Axel; Martini, Cecilia; Reiss, Swantje; Albrecht, Dirk; Budin-Verneuil, Aurélie; Sanguinetti, Maurizio; Engelmann, Susanne; Hain, Torsten; Verneuil, Nicolas

    2014-01-01

    Candidate small RNAs (sRNAs) have recently been identified in Enterococcus faecalis, a Gram-positive opportunistic pathogen, and six of these candidate sRNAs with unknown functions were selected for a functional study. Deletion mutants and complemented strains were constructed, and their virulence was tested. We were unable to obtain the ef0869-0870 mutant, likely due to an essential role, and the ef0820-0821 sRNA seemed not to be involved in virulence. In contrast, the mutant lacking ef0408-0409 sRNA, homologous to the RNAII component of the toxin-antitoxin system, appeared more virulent and more able to colonize mouse organs. The three other mutants showed reduced virulence. In addition, we checked the responses of these mutant strains to several stresses encountered in the gastrointestinal tract or during the infection process. In parallel, the activities of the sRNA promoters were measured using transcriptional fusion constructions. To attempt to identify the regulons of these candidate sRNAs, proteomics profiles of the mutant strains were compared with that of the wild type. This showed that the selected sRNAs controlled the expression of proteins involved in diverse cellular processes and the stress response. The combined data highlight the roles of certain candidate sRNAs in the adaptation of E. faecalis to environmental changes and in the complex transition process from a commensal to a pathogen. PMID:24914223

  15. Overexpression, crystallization and preliminary X-ray crystallographic analysis of phosphopantetheine adenylyltransferase from Enterococcus faecalis

    SciTech Connect

    Kang, Ji Yong; Lee, Hyung Ho; Yoon, Hye Jin; Kim, Hyoun Sook; Suh, Se Won

    2006-11-01

    Phosphopantetheine adenylyltransferase from En. faecalis was crystallized and X-ray diffraction data were collected to 2.70 Å resolution. Phosphopantetheine adenylyltransferase, an essential enzyme in the coenzyme A biosynthetic pathway, catalyzes the reversible transfer of an adenylyl group from ATP to 4′-phosphopantetheine, yielding 3′-dephospho-CoA and pyrophosphate. Enterococcus faecalis PPAT has been overexpressed in Escherichia coli as a fusion with a C-terminal purification tag and crystallized at 297 K using a reservoir solution consisting of 0.1 M sodium HEPES pH 7.5, 0.8 M sodium dihydrogen phosphate and 0.8 M potassium dihydrogen phosphate. X-ray diffraction data were collected to 2.70 Å at 100 K. The crystals belong to the primitive tetragonal space group P4{sub 1} (or P4{sub 3}), with unit-cell parameters a = b = 160.81, c = 225.68 Å. Four copies of the hexameric molecule are likely to be present in the asymmetric unit, giving a crystal volume per protein weight (V{sub M}) of 3.08 Å{sup 3} Da{sup −1} and a solvent content of 60.1%.

  16. Structural Studies on Cytosolic Domain of Magnesium Transporter MgtE from Enterococcus faecalis

    SciTech Connect

    Ragumani, S.; Sauder, J; Burley, S; Swaminathan, S

    2009-01-01

    Magnesium (Mg{sup 2+}) is an essential element for growth and maintenance of living cells. It acts as a cofactor for many enzymes and is also essential for stability of the plasma membrane. There are two distinct classes of magnesium transporters identified in bacteria that convey Mg{sup 2+} from periplasm to cytoplasm [ATPase-dependent (MgtA and MgtB) and constitutively active (CorA and MgtE)]. Previously published work on Mg{sup 2+} transporters yielded structures of full length MgtE from Thermus thermophilus, determined at 3.5 {angstrom} resolution, and its cytoplasmic domain with and without bond Mg{sup 2+} determined at 2.3 and 3.9 {angstrom} resolution, respectively. Here, they report the crystal structure of the Mg{sup 2+} bound form of the cytosolic portion of MgtE (residues 6-262) from Enterococcus faecalis at 2.2 {angstrom} resolution. The present structure and magnesium bound cytosolic domain structure from T. thermophilus (PDB ID: 2YVY) are structurally similar. Three magnesium binding sites are common to both MgtE full length and the present structure. Their work revealed an additional Mg{sup 2+} binding site in the E. faecalis structure. In this report, they discuss the functional significance of Mg{sup 2+} binding sites in the cytosolic domains of MgtE transporters.

  17. Enterococcus faecalis Clones in Poultry and in Humans with Urinary Tract Infections, Vietnam

    PubMed Central

    Poulsen, Louise Ladefoged; Bisgaard, Magne; Son, Nguyen Thai; Trung, Nguyen Vu; An, Hoang Manh

    2012-01-01

    Enterococcus spp. as pathogens have increased, but the sources of infection often remain unclear. To investigate whether poultry might be a reservoir for E. faecalis–associated urinary tract infections (UTIs) in humans, we characterized E. faecalis isolates from patients in Vietnam with UTIs during January 2008–January 2010 and poultry living in close contact with them by multilocus sequence typing (MLST), pulsed-field gel electrophoresis, analysis of antimicrobial drug susceptibility patterns, and sequencing of virulence genes. In 7 (23%) of 31 UTI cases, we detected identical MLST, indistinguishable or closely related pulsed-field gel electrophoresis patterns, and similar antimicrobial drug susceptibility patterns. Isolates from urine and poultry showed identical virulence gene profiles, except for 1 variation, and individual genes showed identical sequences. The homology of isolates from urine and poultry further indicates the zoonotic potential and global spread of E. faecalis sequence type 16, which recently was reported in humans with endocarditis and in pigs in Denmark. PMID:22709904

  18. The Natural Surfactant Glycerol Monolaurate Significantly Reduces Development of Staphylococcus aureus and Enterococcus faecalis Biofilms

    PubMed Central

    Hess, Donavon J.; Henry-Stanley, Michelle J.

    2015-01-01

    Abstract Background: Bacterial biofilms are involved in a large proportion of clinical infections, including device-related infections. Unfortunately, biofilm-associated bacteria are typically less susceptible to antibiotics, and infected devices must often be removed. On the basis of a recent observation that lipid-rich biofilm matrix material is present in early biofilm formation and may protect a population of bacteria from interacting with ordinarily diffusible small molecules, we hypothesized that surfactants may be useful in preventing biofilm development. Methods: Experimental Staphylococcus aureus or Enterococcus faecalis biofilms were cultivated on surgical suture suspended in a growth medium supplemented with the natural surfactant glycerol monolaurate (GML) or with a component molecule, lauric acid. After 16 h incubation, the numbers of viable biofilm-associated bacteria were measured by standard microbiologic techniques and biofilm biomass was measured using the colorimetric crystal violet assay. Results: Both GML and lauric acid were effective in inhibiting biofilm development as measured by decreased numbers of viable biofilm-associated bacteria as well as decreased biofilm biomass. Compared with lauric acid on a molar basis, GML represented a more effective inhibitor of biofilms formed by either S. aureus or E. faecalis. Conclusions: Because the natural surfactant GML inhibited biofilm development, resulting data were consistent with the hypothesis that lipids may play an important role in biofilm growth, implying that interfering with lipid formation may help control development of clinically relevant biofilms. PMID:26110557

  19. Effect of ultrasonics on Enterococcus faecalis biofilm in a bovine tooth model.

    PubMed

    Gründling, Grasiela Longhi; Zechin, Janaína Guzzo; Jardim, Wagner Mariano; de Oliveira, Sílvia Dias; de Figueiredo, José Antônio Poli

    2011-08-01

    The purpose of this study was to evaluate in vitro the effect of the ultrasonic irrigation of sodium hypochlorite and EDTA in root canals of bovine teeth infected with Enterococcus faecalis. Eighty-four bovine incisors were inoculated with E. faecalis, remaining in culture for 50 days for biofilm formation. The teeth were divided into four groups: the control group, which received no treatment; the ultrasonic + distilled water group; the conventional irrigation with sodium hypochlorite + EDTA group; and the passive ultrasonic irrigation with sodium hypochlorite + EDTA group. Microbiological tests and analysis in scanning electron microscopy (SEM) were performed. In microbiological testing, groups using sodium hypochlorite did not show bacterial growth. There were significant differences between the control group and the ultrasonic + distilled water group and between these groups and groups using sodium hypochlorite. In SEM analysis, at the canal wall area, there was no significant difference between the groups using sodium hypochlorite, but these were different from the others groups. The control group was significantly different from the ultrasonic + distilled water group. At the exposed tubule area, there was no significant difference between the groups. Passive ultrasonic irrigation can be an aid in cleaning the root canal; however, the main role in bacteria elimination is played by the irrigant. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  20. Genotypic and phenotypic diversity in Enterococcus faecalis: is agar invasion a pathogenicity score?

    PubMed

    Cafini, F; Gómez-Aguado, F; Corcuera, M T; Ramos, C; Bas, P; Collado, L; Gómez-Lus, M L; Prieto, J

    2015-04-01

    The main objective of the present study is to analyze different genotypic and phenotypic traits related to virulence in Enterococcus faecalis, as well as evaluated the agar invasion phenotype in a collection of isolates with different clinical origins. Seventy-nine E. faecalis isolates, with invasive and non-invasive clinical origins, have been used in this work. Presence of cytolysin activator (cylA), gelatinase (gelE), surface protein (esp), aggregation substance (asa1), endocarditis antigen (efaA), and collagen-binding protein (ace) have been analyzed by PCR. Phenotypic characterization included gelatinase activity, haemolysin production, biofilm formation and agar invasion. All the isolates tested harboured at least one of the virulence determinants. The 95.5% of isolates from haematologic samples were positive for agar invasion test, significantly higher than isolates from non-invasive diseases. A significant reduction in relative invasion area was observed in three selected agar-invasive strains after 15 serial passages. It has been observed a significant high prevalence of agar-invasion positive isolates among strains belonged to haematological samples. Agar invasiveness is reduced after adaptation of clinical isolates to laboratory conditions, showing that agar invasion phenotype can be modulate by culture conditions as other virulence factors observed in different bacterial species.

  1. Eradication of Intracanal Enterococcus Faecalis Biofilm by Passive Ultrasonic Irrigation and RinsEndo System

    PubMed Central

    Toljan, Ivana; Bago, Ivona; Anić, Ivica

    2016-01-01

    Aim The aim of the study was to compare the antimicrobial efficacy of three irrigation techniques after the use of standardized volume of NaOCl and with standardized time and irrigation. Methodology Forty-eight single rooted teeth were inoculated with an Enterococcus faecalis suspension for 24 h. The remaining six canals served as negative controls. The 36 root canals were randomly distributed into three experimental groups; group 1, conventional syringe irrigation; group 2, automated-dynamic irrigation (RinsEndo); group 3, passive ultrasonic irrigation (PUI). In the first protocol, the standardized volume of 3% NaOCl (20 mL) was used and in the second protocol, and standardized irrigation time (45 seconds) was used. Samples from root canals were cultured and the colony-forming units (CFUs) were counted. Results When the volume of the irrigant was standardized, RinsEndo was more effective than PUI (p<0.01). When the irrigation time was standardized, there were no significant differences between any irrigation techniques (p>0.05). The RinsEndo group had the highest percentage of minimal counts of E. faecalis CFUs. Conclusions RinsEndo was more effective than PUI only when the volume of the irrigant was standardized. However, the RinsEndo provided higher bacterial reduction in both protocols when using the least amount of the irrigant and providing longer contact time. PMID:27688422

  2. Characterization and Application of Enterocin RM6, a Bacteriocin from Enterococcus faecalis

    PubMed Central

    Chung, Yoon-Kyung; Yousef, Ahmed E.

    2013-01-01

    Use of bacteriocins in food preservation has received great attention in recent years. The goal of this study is to characterize enterocin RM6 from Enterococcus faecalis OSY-RM6 and investigate its efficacy against Listeria monocytogenes in cottage cheese. Enterocin RM6 was purified from E. faecalis culture supernatant using ion exchange column, multiple C18-silica cartridges, followed by reverse-phase high-performance liquid chromatography. The molecular weight of enterocin RM6 is 7145.0823 as determined by mass spectrometry (MS). Tandem mass spectrometry (MS/MS) analysis revealed that enterocin RM6 is a 70-residue cyclic peptide with a head-to-tail linkage between methionine and tryptophan residues. The peptide sequence of enterocin RM6 was further confirmed by sequencing the structural gene of the peptide. Enterocin RM6 is active against Gram-positive bacteria, including L. monocytogenes, Bacillus cereus, and methicillin-resistant Staphylococcus aureus (MRSA). Enterocin RM6 (final concentration in cottage cheese, 80 AU/mL) caused a 4-log reduction in population of L. monocytogenes inoculated in cottage cheese within 30 min of treatment. Therefore, enterocin RM6 has potential applications as a potent antimicrobial peptide against foodborne pathogens in food. PMID:23844357

  3. The Presence and Origin of Enterococcus faecalis in Cabo Rojo, Puerto Rico

    NASA Astrophysics Data System (ADS)

    Zachman, A. J.; Sturm, P.; Viqueira Ríos, R.

    2015-12-01

    Currently, a watershed management plan is being developed for Cabo Rojo region in Southwest Puerto Rico. This project fills in major gaps for water quality data on the Rio Viejo, a tributary on the Guanajibio River. The Rio Viejo flows through the town of Cabo Rojo, a town of 51,245 people. The project has identified 5 sites along the river to track bacterial loads. In the tropics, Enterococcus faecalis is an important indicator for fecal contamination in surface waters as it does not reproduce as quickly soils as E. coli. A combination of EPA 1600 and 9230B from Standard Methods for the Examination of Water and Wastewater for identification of E. faecalis were utilized. The assay is a four step procedure that identifies the four criteria of bacteria in the group D Streptococcus system. The criteria require that the bacteria are Gram-positive cocci and Esculin-positive. There also must be growth in Brain Heart Infusion Broth at 35C and 45C as well as growth in Brain Heart Infusion broth + 6.5% NaCl. Further research will be conducted at North Carolina State University to ascertain the vertebrate species that is the source of the contamination through the use of qPCR.

  4. Efficacy of a combined nanoparticulate/calcium hydroxide root canal medication on elimination of Enterococcus faecalis.

    PubMed

    Javidi, Maryam; Afkhami, Farzaneh; Zarei, Mina; Ghazvini, Kiarash; Rajabi, Omid

    2014-08-01

    The purpose of this study was to evaluate the efficacy of Ca(OH)2 with or without a silver nanoparticle suspension to eliminate Enterococcus faecalis from root canals. A total of 66 extracted human single-rooted teeth contaminated with E. faecalis were treated with 10% Ca(OH)2 alone, Ca(OH)2 with nanosilver or sterile water (as a negative control). Samples were obtained with paper points and Gates-Glidden burs at 1 and 7 days after root canal preparation and the number of colony-forming units (CFU) was determined. The number of CFUs observed after dressing with Ca(OH)2  + nanosilver was significantly less than the number observed with Ca(OH)2 alone after 1 or 7 days (P < 0.001, P < 0.001). No differences in antimicrobial properties were observed between the two time points in the Ca(OH)2  + nanosilver group (P > 0.05). Higher antimicrobial efficacy was observed in the Ca(OH)2 group after 7 days than 1 day (P < 0.001). This study highlighted the potential advantage of using a mixture of Ca(OH)2 and nanosilver for intracanal medicament. © 2013 The Authors. Australian Endodontic Journal © 2013 Australian Society of Endodontology.

  5. The Intraperitoneal Transcriptome of the Opportunistic Pathogen Enterococcus faecalis in Mice

    PubMed Central

    Muller, Cécile; Cacaci, Margherita; Sauvageot, Nicolas; Sanguinetti, Maurizio; Rattei, Thomas; Eder, Thomas; Giard, Jean-Christophe; Kalinowski, Jörn; Hain, Torsten; Hartke, Axel

    2015-01-01

    Enterococcus faecalis is a Gram-positive lactic acid intestinal opportunistic bacterium with virulence potential. For a better understanding of the adapation of this bacterium to the host conditions, we performed a transcriptome analysis of bacteria isolated from an infection site (mouse peritonitis) by RNA-sequencing. We identified a total of 211 genes with significantly higher transcript levels and 157 repressed genes. Our in vivo gene expression database reflects well the infection process since genes encoding important virulence factors like cytolysin, gelatinase or aggregation substance as well as stress response proteins, are significantly induced. Genes encoding metabolic activities are the second most abundant in vivo induced genes demonstrating that the bacteria are metabolically active and adapt to the special nutrient conditions of the host. α- and β- glucosides seem to be important substrates for E. faecalis inside the host. Compared to laboratory conditions, the flux through the upper part of glycolysis seems to be reduced and more carbon may enter the pentose phosphate pathway. This may reflect the need of the bacteria under infection conditions to produce more reducing power for biosynthesis. Another important substrate is certainly glycerol since both pathways of glycerol catabolism are strongly induced. Strongly in vivo induced genes should be important for the infection process. This assumption has been verified in a virulence test using well characterized mutants affected in glycerol metabolism. This showed indeed that mutants unable to metabolize this sugar alcohol are affected in organ colonisation in a mouse model. PMID:25978463

  6. The Intraperitoneal Transcriptome of the Opportunistic Pathogen Enterococcus faecalis in Mice.

    PubMed

    Muller, Cécile; Cacaci, Margherita; Sauvageot, Nicolas; Sanguinetti, Maurizio; Rattei, Thomas; Eder, Thomas; Giard, Jean-Christophe; Kalinowski, Jörn; Hain, Torsten; Hartke, Axel

    2015-01-01

    Enterococcus faecalis is a Gram-positive lactic acid intestinal opportunistic bacterium with virulence potential. For a better understanding of the adapation of this bacterium to the host conditions, we performed a transcriptome analysis of bacteria isolated from an infection site (mouse peritonitis) by RNA-sequencing. We identified a total of 211 genes with significantly higher transcript levels and 157 repressed genes. Our in vivo gene expression database reflects well the infection process since genes encoding important virulence factors like cytolysin, gelatinase or aggregation substance as well as stress response proteins, are significantly induced. Genes encoding metabolic activities are the second most abundant in vivo induced genes demonstrating that the bacteria are metabolically active and adapt to the special nutrient conditions of the host. α- and β- glucosides seem to be important substrates for E. faecalis inside the host. Compared to laboratory conditions, the flux through the upper part of glycolysis seems to be reduced and more carbon may enter the pentose phosphate pathway. This may reflect the need of the bacteria under infection conditions to produce more reducing power for biosynthesis. Another important substrate is certainly glycerol since both pathways of glycerol catabolism are strongly induced. Strongly in vivo induced genes should be important for the infection process. This assumption has been verified in a virulence test using well characterized mutants affected in glycerol metabolism. This showed indeed that mutants unable to metabolize this sugar alcohol are affected in organ colonisation in a mouse model.

  7. vanE gene cluster of vancomycin-resistant Enterococcus faecalis BM4405.

    PubMed

    Abadía Patiño, Lorena; Courvalin, Patrice; Perichon, Bruno

    2002-12-01

    Acquired VanE-type resistance to low levels of vancomycin (MIC = 16 microg/ml) in Enterococcus faecalis BM4405 is due to the inducible synthesis of peptidoglyean precursors terminating in D-alanine-D-serine (Fines,M., B. Prichon, P. Reynolds, D. Sahm, and P. Courvalin, Antimicrob. Agents Chemother. 43:2161-2164, 1999). A chromosomal location was assigned to the vanE operon by pulsed-field gel electrophoresis and hybridization, and its sequence was determined. Three genes, encoding the VanE ligase, the VanXYE DD-peptidase, and the VanTE serine racemase, that displayed 43 to 53% identity with the corresponding genes in the vanC operon were found. In addition, two genes coding for a two-component regulatory system, VanRE-VanSE, exhibiting 60 and 44% identity with VanR,-VanS, were present downstream from vanTE. However, because of a stop codon at position 78, VanSE was probably not functional. The five genes, with the same orientation, were shown to be cotranscribed by Northern analysis and reverse transcription-PCR. The vanE, vanXYE, and vanTE genes conferred inducible low-level resistance to vancomycin after cloning in E. faecalis JH2-2, probably following cross talk with a two-component regulatory system of the host.

  8. Endophthalmitis Caused by Enterococcus faecalis: Clinical Features, Antibiotic Sensitivities, and Outcomes

    PubMed Central

    Kuriyan, Ajay E.; Sridhar, Jayanth; Flynn, Harry W.; Smiddy, William E.; Albini, Thomas A.; Berrocal, Audina M.; Forster, Richard K.; Belin, Peter J.; Miller, Darlene

    2014-01-01

    Purpose To report the clinical features, antibiotic sensitivities, and visual acuity (VA) outcomes of endophthalmitis caused by Enterococcus faecalis. Study Design Retrospective, observational case series. Methods A consecutive case series of patients with culture-positive endophthalmitis caused by E. faecalis between January 1, 2002 and December 31, 2012 at an academic referral center. Results Of 14 patients identified, clinical settings included bleb-associated (n=8), post-cataract surgery (n=4), and post-penetrating keratoplasty (n=2). All isolates were vancomycin sensitive. When comparing isolates in the current study to isolates from 1990–2001, the minimal inhibitory concentration required to inhibit 90% of isolates (MIC 90, μg/ml) increased for ciprofloxacin (4 from 1), erythromycin (256 from 4), and penicillin (8 from 4), indicating higher levels of resistance. The MIC 90 remained the same for vancomycin (2) and linezolid (2). Presenting VA ranged from hand motion to no light perception. Initial treatment strategies were vitreous tap and intravitreal antibiotic injection (n=12) and pars plana vitrectomy with intravitreal antibiotic injection (n=2). VA outcomes were ≤ 20/400 in 13 (93%) of 14 patients. Conclusions Although all isolates were sensitive to vancomycin and linezolid, higher MIC 90s for isolates in the current study, compared to isolates from 1990 to 2001, occurred with ciprofloxacin, erythromycin, and penicillin. Despite prompt treatment, most patients had poor outcomes. PMID:25089354

  9. Molecular cloning, overexpression, purification, and characterization of an aerobic FMN-dependent azoreductase from Enterococcus faecalis.

    PubMed

    Chen, Huizhong; Wang, Rong-Fu; Cerniglia, Carl E

    2004-04-01

    Azo dyes represent a major class of synthetic colorants that are ubiquitous in foods and consumer products. Enterococcus faecalis is a predominant member of the human gastrointestinal microflora. Strain ATCC 19433 grew in the presence of azo dyes and metabolized them to colorless products. A gene encoding a putative FMN-dependent aerobic azoreductase that shares 34% identity with azoreductase (AcpD) of Escherichia coli has been identified in this strain. The gene in E. faecalis, designated as azoA, encoded a protein of 208 amino acids with a calculated isoelectric point of 4.8. AzoA was heterologously overexpressed in E. coli with a strong band of 23 kDa on SDS-PAGE. The purified recombinant enzyme was a homodimer with a molecular weight of 43 kDa, probably containing one molecule of FMN per dimer. AzoA required FMN and NADH, but not NADPH, as a preferred electron donor for its activity. The apparent Km values for both NADH and 2-[4-(dimethylamino)phenylazo]benzoic acid (Methyl red) substrates were 0.14 and 0.024 mM, respectively. The apparent Vmax was 86.2 microM/min/mg protein. The enzyme was not only able to decolorize Methyl red, but was also able to convert sulfonated azo dyes Orange II, Amaranth, Ponceau BS, and Ponceau S. AzoA is the first aerobic azoreductase to be identified and characterized from human intestinal gram-positive bacteria.

  10. Involvement of Enterococcus faecalis small RNAs in stress response and virulence.

    PubMed

    Michaux, Charlotte; Hartke, Axel; Martini, Cecilia; Reiss, Swantje; Albrecht, Dirk; Budin-Verneuil, Aurélie; Sanguinetti, Maurizio; Engelmann, Susanne; Hain, Torsten; Verneuil, Nicolas; Giard, Jean-Christophe

    2014-09-01

    Candidate small RNAs (sRNAs) have recently been identified in Enterococcus faecalis, a Gram-positive opportunistic pathogen, and six of these candidate sRNAs with unknown functions were selected for a functional study. Deletion mutants and complemented strains were constructed, and their virulence was tested. We were unable to obtain the ef0869-0870 mutant, likely due to an essential role, and the ef0820-0821 sRNA seemed not to be involved in virulence. In contrast, the mutant lacking ef0408-0409 sRNA, homologous to the RNAII component of the toxin-antitoxin system, appeared more virulent and more able to colonize mouse organs. The three other mutants showed reduced virulence. In addition, we checked the responses of these mutant strains to several stresses encountered in the gastrointestinal tract or during the infection process. In parallel, the activities of the sRNA promoters were measured using transcriptional fusion constructions. To attempt to identify the regulons of these candidate sRNAs, proteomics profiles of the mutant strains were compared with that of the wild type. This showed that the selected sRNAs controlled the expression of proteins involved in diverse cellular processes and the stress response. The combined data highlight the roles of certain candidate sRNAs in the adaptation of E. faecalis to environmental changes and in the complex transition process from a commensal to a pathogen.

  11. Bactericial effect of a non-thermal plasma needle against Enterococcus faecalis biofilms

    NASA Astrophysics Data System (ADS)

    Jiang, Chunqi; Schaudinn, C.; Jaramillo, D. E.; Sedghizadeh, P. P.; Webster, P.; Costerton, J. W.

    2011-10-01

    Up to 3 cm long submillimeter-in-scale plasma needle was generated in ambient atmosphere for root canal disinfection. Powered with 1-2 kHz, multi-kilovolt nanosecond electric pulses, this He/(1%)O2 plasma jet consists of ionization fronts propagating at speeds of the order of 107 cm/s. Plasma treatment of Enterococcus faecalis biofilms on hydroxyapatite (HA) discs for 5 min resulted in severe damage of the bacterial cells and sterilized HA surfaces of more than 3 mm in diameter, observed by the scanning electron microscopy. With a curing dielectric microtube placed 1 cm or less below the nozzle, the plasma jet entered even at a sharp angle and followed the curvature of the tube, and reached the bottom of the tube. The bactericidal effect of the plasma needle against E. faecalis biofilm grown on the inner surfaces of the tube was demonstrated. However, the bactericidal effect weakens or diminishes for the bacteria grown deeper in the tube, indicating improvement of the plasma treatment scheme is needed. Mechanisms of the plasma bactericidal effects are discussed. Supported by the National Institute of Dental and Craniofacial Research and the Air Force Office of Scientific Research.

  12. Identification and Characterization of a Bacitracin Resistance Network in Enterococcus faecalis

    PubMed Central

    Fang, Chong; Shaaly, Aishath; Leslie, David J.; Weimar, Marion R.; Kalamorz, Falk; Carne, Alan; Cook, Gregory M.

    2014-01-01

    Resistance of Enterococcus faecalis against antimicrobial peptides, both of host origin and produced by other bacteria of the gut microflora, is likely to be an important factor in the bacterium's success as an intestinal commensal. The aim of this study was to identify proteins with a role in resistance against the model antimicrobial peptide bacitracin. Proteome analysis of bacitracin-treated and untreated cells showed that bacitracin stress induced the expression of cell wall-biosynthetic proteins and caused metabolic rearrangements. Among the proteins with increased production, an ATP-binding cassette (ABC) transporter with similarity to known peptide antibiotic resistance systems was identified and shown to mediate resistance against bacitracin. Expression of the transporter was dependent on a two-component regulatory system and a second ABC transporter, which were identified by genome analysis. Both resistance and the regulatory pathway could be functionally transferred to Bacillus subtilis, proving the function and sufficiency of these components for bacitracin resistance. Our data therefore show that the two ABC transporters and the two-component system form a resistance network against antimicrobial peptides in E. faecalis, where one transporter acts as the sensor that activates the TCS to induce production of the second transporter, which mediates the actual resistance. PMID:24342648

  13. Identification and characterization of a bacitracin resistance network in Enterococcus faecalis.

    PubMed

    Gebhard, Susanne; Fang, Chong; Shaaly, Aishath; Leslie, David J; Weimar, Marion R; Kalamorz, Falk; Carne, Alan; Cook, Gregory M

    2014-01-01

    Resistance of Enterococcus faecalis against antimicrobial peptides, both of host origin and produced by other bacteria of the gut microflora, is likely to be an important factor in the bacterium's success as an intestinal commensal. The aim of this study was to identify proteins with a role in resistance against the model antimicrobial peptide bacitracin. Proteome analysis of bacitracin-treated and untreated cells showed that bacitracin stress induced the expression of cell wall-biosynthetic proteins and caused metabolic rearrangements. Among the proteins with increased production, an ATP-binding cassette (ABC) transporter with similarity to known peptide antibiotic resistance systems was identified and shown to mediate resistance against bacitracin. Expression of the transporter was dependent on a two-component regulatory system and a second ABC transporter, which were identified by genome analysis. Both resistance and the regulatory pathway could be functionally transferred to Bacillus subtilis, proving the function and sufficiency of these components for bacitracin resistance. Our data therefore show that the two ABC transporters and the two-component system form a resistance network against antimicrobial peptides in E. faecalis, where one transporter acts as the sensor that activates the TCS to induce production of the second transporter, which mediates the actual resistance.

  14. Antibacterial Efficacy of Calcium Hypochlorite with Vibringe Sonic Irrigation System on Enterococcus faecalis: An In Vitro Study

    PubMed Central

    Dumani, Aysin; Guvenmez, Hatice Korkmaz; Yilmaz, Sehnaz; Yoldas, Oguz; Kurklu, Zeliha Gonca Bek

    2016-01-01

    Aim. The purpose of this study was to compare the in vitro efficacy of calcium hypochlorite (Ca[OCl]2) and sodium hypochlorite (NaOCl) associated with sonic (Vibringe) irrigation system in root canals which were contaminated with Enterococcus faecalis. Material and Methods. The root canals of 84 single-rooted premolars were enlarged up to a file 40, autoclaved, inoculated with Enterococcus faecalis, and incubated for 21 days. The samples were divided into 7 groups according to the irrigation protocol: G0: no treatment; G1: distilled water; G2: 2.5% NaOCl; G3: 2.5% Ca(OCl)2; G4: distilled water with sonic activation; G5: 2.5% NaOCl with sonic activation; and G6: 2.5% Ca(OCl)2 with sonic activation. Before and after decontamination procedures microbiological samples were collected and the colony-forming units were counted and the percentages of reduction were calculated. Results. Distilled water with syringe irrigation and sonic activation groups demonstrated poor antibacterial effect on Enterococcus faecalis compared to other experimental groups (p < 0.05). There was no statistically significant difference between syringe and sonic irrigation systems with Ca(OCl)2 and NaOCl. Conclusion. The antimicrobial property of Ca(OCl)2 has been investigated and compared with that of NaOCl. Both conventional syringe irrigation and sonic irrigation were found effective at removing E. faecalis from the root canal of extracted human teeth. PMID:27218106

  15. Antibacterial Efficacy of Calcium Hypochlorite with Vibringe Sonic Irrigation System on Enterococcus faecalis: An In Vitro Study.

    PubMed

    Dumani, Aysin; Guvenmez, Hatice Korkmaz; Yilmaz, Sehnaz; Yoldas, Oguz; Kurklu, Zeliha Gonca Bek

    2016-01-01

    Aim. The purpose of this study was to compare the in vitro efficacy of calcium hypochlorite (Ca[OCl]2) and sodium hypochlorite (NaOCl) associated with sonic (Vibringe) irrigation system in root canals which were contaminated with Enterococcus faecalis. Material and Methods. The root canals of 84 single-rooted premolars were enlarged up to a file 40, autoclaved, inoculated with Enterococcus faecalis, and incubated for 21 days. The samples were divided into 7 groups according to the irrigation protocol: G0: no treatment; G1: distilled water; G2: 2.5% NaOCl; G3: 2.5% Ca(OCl)2; G4: distilled water with sonic activation; G5: 2.5% NaOCl with sonic activation; and G6: 2.5% Ca(OCl)2 with sonic activation. Before and after decontamination procedures microbiological samples were collected and the colony-forming units were counted and the percentages of reduction were calculated. Results. Distilled water with syringe irrigation and sonic activation groups demonstrated poor antibacterial effect on Enterococcus faecalis compared to other experimental groups (p < 0.05). There was no statistically significant difference between syringe and sonic irrigation systems with Ca(OCl)2 and NaOCl. Conclusion. The antimicrobial property of Ca(OCl)2 has been investigated and compared with that of NaOCl. Both conventional syringe irrigation and sonic irrigation were found effective at removing E. faecalis from the root canal of extracted human teeth.

  16. Effect of Passive Ultrasonic Irrigation on Enterococcus faecalis from Root Canals: An Ex Vivo Study.

    PubMed

    Guerreiro-Tanomaru, Juliane Maria; Chávez-Andrade, Gisselle Moraima; de Faria-Júnior, Norberto Batista; Watanabe, Evandro; Tanomaru-Filho, Mário

    2015-01-01

    Endodontic irrigation aims to clean and disinfect the root canal system. Passive ultrasonic irrigation (PUI) is based on the use of an ultrasound-activated instrument into the root canal filled with irrigant. The aim of this study was to evaluate, ex vivo, the effectiveness of PUI in eliminating Enterococcus faecalis from root canals. Seventy-five extracted human single-root teeth were used. After root canal preparation, specimens were inoculated with E. faecalis and incubated at 37 °C for 21 days. Specimens were distributed into five groups (n=15), according to the irrigation method: PUI + saline solution (PUI/SS); PUI + 1% NaOCl (PUI/NaOCl); conventional needle irrigation (CNI) + saline solution (CNI/SS); CNI + 1% NaOCl (CNI/NaOCl); No irrigation (control). Microbiological samples were collected at three time points: initial (21 days after inoculation), post-irrigation (immediately after irrigation), and final (7 days after irrigation). Data were obtained in CFU mL-1 and subjected to analysis by ANOVA and Tukey's tests at 5% significance level. The post-irrigation samples did not demonstrate statistical difference between PUI/SS and CNI/SS nor between PUI/NaOCl and CNI/NaOCl (p>0.05), but PUI/NaOCl and CNI/NaOCl had lower CFU mL-1 number than the other groups (p>0.05). Statistically significant difference was observed between the initial and post-irrigation samples and between the post-irrigation and final samples (p<0.05) in all groups, except in the control. The final samples of all groups presented bacterial counts similar to the initial samples. PUI or CNI with 1% NaOCl contribute to disinfection, but are unable to eradicate E. faecalis from the root canal system.

  17. Bactericidal effect of plasma jet with helium flowing through 3% hydrogen peroxide against Enterococcus faecalis

    PubMed Central

    Zhou, Xin-Cai; Li, Yu-Lan; Liu, De-Xi; Cao, Ying-Guang; Lu, Xin-Pei

    2016-01-01

    The aim of the present study was to assess the antimicrobial activity of plasma jet with helium (He) flowing through 3% hydrogen peroxide in root canals infected with Enterococcus faecalis. A total of 42 single-rooted anterior teeth were prepared, sterilized, inoculated with an E. faecalis suspension and incubated for 7 days. Next, the teeth were randomly divided into six experimental groups (including groups treated by plasma jet with or without He for different time durations) and one control group treated without plasma. The number of surviving bacteria in each canal was determined by counting the colony forming units (CFU)/ml on nutrient agar plates. The results indicated that statistically significant reduction in CFU/ml (P<0.005) existed for all treatment groups relative to the control group. The greatest reductions in CFU/ml were observed for Group 3 (7.027 log unit reduction) and Group 2 (6.237 log unit reduction), which were treated by plasma jet sterilization with He flowing through 3% hydrogen peroxide for 4 min or for 2 min, respectively. In addition, the reduction in Group 3 was significantly greater compared with that in Group 2 or in the groups treated by plasma jet sterilization without He flowing through 3% hydrogen peroxide for 1, 2 or 4 min. In conclusion, plasma jet with or without He flowing through 3% hydrogen peroxide can effectively sterilized root canals infected with E. faecalis and should be considered as an alternative method for root canal disinfection in endodontic treatments. PMID:27882119

  18. Targeted sampling protocol as prelude to bacterial source tracking with Enterococcus faecalis.

    PubMed

    Kuntz, Robin L; Hartel, Peter G; Godfrey, Dominique G; McDonald, Jennifer L; Gates, Keith W; Segars, William I

    2003-01-01

    Recent studies suggest that host origin databases for bacterial source tracking (BST) must contain a large number of isolates because bacterial subspecies change with geography and time. A new targeted sampling protocol was developed as a prelude to BST to minimize these changes. The research was conducted on the Sapelo River, a tidal river on the Georgia coast. A general sampling of the river showed fecal enterococcal numbers ranging from <10 (below the limit of detection) to 990 colony-forming units (CFU) per 100 mL. Locations with high enterococcal numbers were combined with local knowledge to determine targeted sampling sites. Fecal enterococcal numbers around one site ranged from <10 to 24,000 CFU per 100 mL. Bacterial source tracking was conducted to determine if a wastewater treatment facility at the site was responsible for this contamination. The fecal indicator bacterium was Enterococcus faecalis. Ribotyping, automated with a RiboPrinter (DuPont Qualicon, Wilmington, DE), was the BST method. Thirty-seven ribotypes were observed among 83 Ent. faecalis isolates obtained from the Sapelo River and the wastewater lagoon. Sixteen ribotypes were associated with either the river or the lagoon, and only five ribotypes (14%) were shared. Nevertheless, these five ribotypes represented 39 of the 83 Ent. faecalis isolates, almost a majority (47%). These results suggest that the fecal contamination in the river came from the wastewater treatment facility. As a prelude to BST, targeted sampling minimized subspecies changes with geography and time, and eliminated the need for a permanent host origin database by restricting BST to a small geographic area and requiring sampling to be completed in one day.

  19. Probing surface adhesion forces of Enterococcus faecalis to medical-grade polymers using atomic force microscopy.

    PubMed

    Sénéchal, Annie; Carrigan, Shawn D; Tabrizian, Maryam

    2004-05-11

    The aim of this study was to compare the initial adhesion forces of the uropathogen Enterococcus faecalis with the medical-grade polymers polyurethane (PU), polyamide (PA), and poly(tetrafluoroethylene) (PTFE). To quantify the cell-substrate adhesion forces, a method was developed using atomic force microscopy (AFM) in liquid that allows for the detachment of individual live cells from a polymeric surface through the application of increasing force using unmodified cantilever tips. Results show that the lateral force required to detach E. faecalis cells from a substrate differed depending on the nature of the polymeric surface: a force of 19 +/- 4 nN was required to detach cells from PU, 6 +/- 4 nN from PA, and 0.7 +/- 0.3 nN from PTFE. Among the unfluorinated polymers (PU and PA), surface wettability was inversely proportional to the strength of adhesion. AFM images also demonstrated qualitative differences in bacterial adhesion; PU was covered by clusters of cells with few cell singlets present, whereas PA was predominantly covered by individual cells. Moreover, extracellular material could be observed on some clusters of PU-adhered cells as well as in the adjacent region surrounding cells adhered on PA. E. faecalis adhesion to the fluorinated polymer (PTFE) showed different characteristics; only a few individual cells were found, and bacteria were easily damaged, and thus detached, by the tip. This work demonstrates the utility of AFM for measurement of cell-substrate lateral adhesion forces and the contribution these forces make toward understanding the initial stages of bacterial adhesion. Further, it suggests that initial adhesion can be controlled, through appropriate biomaterial design, to prevent subsequent formation of aggregates and biofilms.

  20. Effect of Antimicrobials Used in Regenerative Endodontic Procedures on 3-week-old Enterococcus faecalis Biofilm.

    PubMed

    Tagelsir, Azza; Yassen, Ghaeth H; Gomez, Grace F; Gregory, Richard L

    2016-02-01

    We evaluated the effect of various antimicrobials used in endodontic regeneration on a 3-week-old Enterococcus faecalis biofilm. E. faecalis biofilm was grown on standardized dentin samples for 3 weeks. Infected dentin samples were randomized into 8 experimental groups (n = 8) and treated with calcium hydroxide (Ca[OH]2), 500 mg/mL of double antibiotic paste (DAP, equal portions of metronidazole and ciprofloxacin), low dilutions of DAP (1 or 0.1 mg/mL loaded into a methylcellulose vehicle system), sterile saline, or placebo paste (only methylcellulose) for 7 days. The other experimental groups were treated with 1.5% sodium hypochlorite (NaOCl) or 2% chlorhexidine gluconate (CHX) solutions for 5 minutes. After the assigned treatments, the bacterial biofilms were detached from dentin, spiral plated, and quantified using an automated counting machine. Permutation tests followed by Sidak post hoc multiple comparisons were used for statistical analyses (α = 0.05). The infected dentin treated with 1.5% NaOCl or 500 mg/mL of DAP provided complete eradication of bacterial biofilm. Furthermore, the infected dentin treated with 2% CHX, Ca(OH)2, or 1 mg/mL of DAP had a comparable antibiofilm effect, but they were not able to completely eradicate bacterial biofilm. No significant difference in the antibiofilm effect was observed between 500 mg/mL of DAP, Ca(OH)2, 1.5% NaOCl, and 2% CHX. At least 1 mg/mL of DAP in a methylcellulose vehicle system is required to eliminate a substantial amount of E. faecalis biofilm. Furthermore, the antibiofilm effects of 1.5% NaOCl and 2% CHX irrigation solutions were comparable with that of 500 mg/mL of DAP and Ca(OH)2. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  1. Basal Levels of (p)ppGpp in Enterococcus faecalis: the Magic beyond the Stringent Response

    PubMed Central

    Gaca, Anthony O.; Kajfasz, Jessica K.; Miller, James H.; Liu, Kuanqing; Wang, Jue D.; Abranches, Jacqueline; Lemos, José A.

    2013-01-01

    ABSTRACT The stringent response (SR), mediated by the alarmone (p)ppGpp, is a conserved bacterial adaptation system controlling broad metabolic alterations necessary for survival under adverse conditions. In Enterococcus faecalis, production of (p)ppGpp is controlled by the bifunctional protein RSH (for “Rel SpoT homologue”; also known as RelA) and by the monofunctional synthetase RelQ. Previous characterization of E. faecalis strains lacking rsh, relQ, or both revealed that RSH is responsible for activation of the SR and that alterations in (p)ppGpp production negatively impact bacterial stress survival and virulence. Despite its well-characterized role as the effector of the SR, the significance of (p)ppGpp during balanced growth remains poorly understood. Microarrays of E. faecalis strains producing different basal amounts of (p)ppGpp identified several genes and pathways regulated by modest changes in (p)ppGpp. Notably, expression of numerous genes involved in energy generation were induced in the ∆rsh ∆relQ [(p)ppGpp0] strain, suggesting that a lack of basal (p)ppGpp places the cell in a “transcriptionally relaxed” state. Alterations in the fermentation profile and increased production of H2O2 in the (p)ppGpp0 strain substantiate the observed transcriptional changes. We confirm that, similar to what is seen in Bacillus subtilis, (p)ppGpp directly inhibits the activity of enzymes involved in GTP biosynthesis, and complete loss of (p)ppGpp leads to dysregulation of GTP homeostasis. Finally, we show that the association of (p)ppGpp with antibiotic survival does not relate to the SR but rather relates to basal (p)ppGpp pools. Collectively, this study highlights the critical but still underappreciated role of basal (p)ppGpp pools under balanced growth conditions. PMID:24065631

  2. Comparative Genomics and Transduction Potential of Enterococcus faecalis Temperate Bacteriophages▿ †

    PubMed Central

    Yasmin, Azra; Kenny, John G.; Shankar, Jayendra; Darby, Alistair C.; Hall, Neil; Edwards, Clive; Horsburgh, Malcolm J.

    2010-01-01

    To determine the relative importance of temperate bacteriophage in the horizontal gene transfer of fitness and virulence determinants of Enterococcus faecalis, a panel of 47 bacteremia isolates were treated with the inducing agents mitomycin C, norfloxacin, and UV radiation. Thirty-four phages were purified from culture supernatants and discriminated using pulsed-field gel electrophoresis (PFGE) and restriction mapping. From these analyses the genomes of eight representative phages were pyrosequenced, revealing four distinct groups of phages. Three groups of phages, ΦFL1 to 3, were found to be sequence related, with ΦFL1A to C and ΦFL2A and B sharing the greatest identity (87 to 88%), while ΦFL3A and B share 37 to 41% identity with ΦFL1 and 2. ΦFL4A shares 3 to 12% identity with the phages ΦFL1 to 3. The ΦFL3A and B phages possess a high DNA sequence identity with the morphogenesis and lysis modules of Lactococcus lactis subsp. cremoris prophages. Homologs of the Streptococcus mitis platelet binding phage tail proteins, PblA and PblB, are encoded on each sequenced E. faecalis phage. Few other phage genes encoding potential virulence functions were identified, and there was little evidence of carriage of lysogenic conversion genes distal to endolysin, as has been observed with genomes of many temperate phages from the opportunist pathogens Staphylococcus aureus and Streptococcus pyogenes. E. faecalis JH2-2 lysogens were generated using the eight phages, and these were examined for their relative fitness in Galleria mellonella. Several lysogens exhibited different effects upon survival of G. mellonella compared to their isogenic parent. The eight phages were tested for their ability to package host DNA, and three were shown to be very effective for generalized transduction of naive host cells of the laboratory strains OG1RF and JH2-2. PMID:20008075

  3. Heterologous expression of glycopeptide resistance vanHAX gene clusters from soil bacteria in Enterococcus faecalis.

    PubMed

    Hasman, Henrik; Aarestrup, Frank M; Dalsgaard, Anders; Guardabassi, Luca

    2006-04-01

    The aim of the study was to determine whether glycopeptide resistance gene clusters from soil bacteria could be heterologously expressed in Enterococcus faecalis and adapt to the new host following exposure to vancomycin. The vanHAX clusters from Paenibacillus thiaminolyticus PT-2B1, Paenibacillus apiarius PA-B2B and Amycolatopsis coloradensis DSM 44225 were separately cloned in an appropriately constructed shuttle vector containing the two-component regulatory system (vanRS) of Tn1546. The complete vanA(PT) operon (vanRSHAXY) from P. thiaminolyticus PT-2B1 was cloned in the same shuttle vector lacking enterococcal vanRS. All plasmid constructs were electroporated into E. faecalis JH2-2 and the MICs of vancomycin and teicoplanin were determined for each recombinant strain before and following exposure to sublethal concentrations of vancomycin. The vanHAX clusters from P. thiaminolyticus and P. apiarius conferred high-level vancomycin resistance (MIC > or = 125 mg/L) in E. faecalis JH2-2. In contrast, cloning of the vanHAX cluster from A. coloradensis did not result in a significant increase of vancomycin resistance (MIC = 0.7 mg/L). Resistance to vancomycin was not observed after cloning the complete vanA(PT) operon from P. thiaminolyticus (MIC = 2 mg/L), but this recombinant rapidly adapted to high concentrations of vancomycin (MIC = 500 mg/L) following exposure to sub-lethal concentrations of this antibiotic. The results showed that vanA(PT) in P. thiaminolyticus is a possible ancestor of vanA-mediated glycopeptide resistance in enterococci. Experimental evidence supported the hypothesis that enterococci did not acquire glycopeptide resistance directly from glycopeptide-producing organisms such as A. coloradensis.

  4. Teicoplanin versus vancomycin for prophylaxis of experimental Enterococcus faecalis endocarditis in rats.

    PubMed Central

    Entenza, J M; Calandra, T; Moosmann, Y; Malinverni, R; Glauser, M P

    1992-01-01

    Teicoplanin was compared with vancomycin for the prophylaxis of experimental Enterococcus faecalis endocarditis in rats. Single intravenous doses of teicoplanin (7 mg/kg of body weight) or vancomycin (15 mg/kg) were given 30 min before bacterial challenge. Two strains of E. faecalis (309 and 1209) isolated from patients with endocarditis were tested. Bacterial inocula ranged from 10(4) (i.e., the inoculum infecting 90% of the control rats [ID90]) to 10(7) CFU/ml. The MICs and MBCs of teicoplanin and vancomycin were, respectively, 0.25 to greater than 128 mg/liter and 2 to greater than 128 mg/liter for strain 309 and 0.5 to greater than 128 mg/liter and 0.5 to greater than 128 mg/liter for strain 1209. Vancomycin prevented endocarditis only in 60% (strain 309) and in 87% (strain 1209) of rats challenged with the smallest bacterial-inoculum size (ID90), whereas teicoplanin prevented endocarditis in 100% of rats challenged with the same inoculum (strain 309; P = 0.05), in 87% of rats challenged with 10 times the ID90 (strain 309; P = 0.02), and in 95% of rats challenged with 100 times the ID90 (strain 1209; P = 0.0003). The combination of teicoplanin plus gentamicin (4 mg/kg) extended the protection to inocula 100 times the ID90 (strain 309; 96% of sterile animals) and 1,000 times the ID90 (strain 1209; 100% of sterile animals). Prevention of endocarditis was likely to be due to a prolonged inhibition of bacterial growth by sustained levels of teicoplanin in serum and not to bacterial killing. Indeed, teicoplanin did not exhibit any bactericidal activity either in vitro (time-kill curves) or in vivo (serum bactericidal activity). Teicoplanin proved to be superior to vancomycin in the prophylaxis of experimental E. faecalis endocarditis in rats. PMID:1416824

  5. Evaluation of the antibacterial efficacy of silver nanoparticles against Enterococcus faecalis biofilm.

    PubMed

    Wu, Daming; Fan, Wei; Kishen, Anil; Gutmann, James L; Fan, Bing

    2014-02-01

    The purpose of this study was to evaluate the antibacterial efficacy of silver nanoparticles (AgNPs) as an irrigant or medicament against Enterococcus faecalis biofilms formed on root dentin. Dentin sections were inoculated with E. faecalis for 4 weeks to establish a standard monospecies biofilm model. These biofilms were tested in 2 stages. In stage 1, the biofilms were irrigated with 0.1% AgNP solution, 2% sodium hypochlorite, and sterile saline for 2 minutes, respectively. In stage 2, the biofilms were treated with AgNP gel (0.02% and 0.01%) and calcium hydroxide for 7 days. The ultrastructure of one half of the specimens from each group was evaluated by using scanning electron microscopy, whereas the structure and distribution of viable bacteria of the other half of the specimens were assessed with confocal laser scanning microscopy combined with viability staining. Syringe irrigation with 0.1% AgNP solution did not disrupt the biofilm structure, and the proportion of viable bacteria in the biofilm structures was not different from that of the saline group (P > .05) but was less than that of the control group (P < .05). The biofilms treated with 0.02% AgNP gel as medicament significantly disrupted the structural integrity of the biofilm and resulted in the least number of post-treatment residual viable E. faecalis cells compared with 0.01% AgNP gel and calcium hydroxide groups (P < .05). The findings from this study suggested that the antibiofilm efficacy of AgNPs depends on the mode of application. AgNPs as a medicament and not as an irrigant showed potential to eliminate residual bacterial biofilms during root canal disinfection. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  6. Human salivary proteins with affinity to lipoteichoic acid of Enterococcus faecalis.

    PubMed

    Baik, Jung Eun; Choe, Hyuk-Il; Hong, Sun Woong; Kang, Seok-Seong; Ahn, Ki Bum; Cho, Kun; Yun, Cheol-Heui; Han, Seung Hyun

    2016-09-01

    Enterococcus faecalis is associated with refractory apical periodontitis and its lipoteichoic acid (Ef.LTA) is considered as a major virulence factor. Although the binding proteins of Ef.LTA may play an important role for mediating infection and immunity in the oral cavity, little is known about Ef.LTA-binding proteins (Ef.LTA-BPs) in saliva. In this study, we identified salivary Ef.LTA-BPs with biotinylated Ef.LTA (Ef.LTA-biotin) through mass spectrometry. The biotinylation of Ef.LTA was confirmed by binding capacity with streptavidin-FITC on CHO/CD14/TLR2 cells. The biological activity of Ef.LTA-biotin was determined based on the induction of nitric oxide and macrophage inflammatory protein-1α in a macrophage cell-line, RAW 264.7. To identify salivary Ef.LTA-BPs, the Ef.LTA-biotin was mixed with a pool of human saliva obtained from nine healthy subjects followed by precipitation with a streptavidin-coated bead. Ef.LTA-BPs were then separated with 12% SDS-PAGE and subjected to the mass spectrometry. Six human salivary Ef.LTA-BPs including short palate lung and nasal epithelium carcinoma-associated protein 2, zymogen granule protein 16 homolog B, hemoglobin subunit α and β, apolipoprotein A-I, and lipocalin-1 were identified with statistical significance (P<0.05). Ef.LTA-BPs were validated with lipocalin-1 using pull-down assay. Hemoglobin inhibited the biofilm formation of E. faecalis whereas lipocalin-1 did not show such effect. Collectively, the identified Ef.LTA-BPs could provide clues for our understanding of the pathogenesis of E. faecalis and host immunity in oral cavity. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Photodynamic therapy in root canals contaminated with Enterococcus faecalis using curcumin as photosensitizer.

    PubMed

    da Frota, Matheus Franco; Guerreiro-Tanomaru, Juliane Maria; Tanomaru-Filho, Mario; Bagnato, Vanderlei Salvador; Espir, Camila Galetti; Berbert, Fabio Luis Camargo Villela

    2015-09-01

    The aim of the study was to evaluate the photodynamic therapy (PDT) effect on root canals contaminated with Enterococcus faecalis using a light emitting diode (LED) light and a curcumin solution (CUR) as photosensitizer (PS). Eighty root canals from uniradicular human teeth were prepared with Protaper Universal rotary system and contaminated with E. faecalis for 21 days. They were divided as: GIa-PDT (CUR, pre-irradiation for 5 + 5 min of irradiation); GIb-PDT (CUR, pre-irradiation for 5 + 10 min of irradiation); GIIa-(CUR, pre-irradiation for 5 + 5 min without irradiation); GIIb-(CUR pre-irradiation for 5 + 10 min of irradiation); GIIIa-(physiological solution and irradiation for 5 min); and GIIIb-(physiological solution and irradiation for 10 min); positive and negative control groups. Collections from root canals were made at time intervals of 21 days after contamination, immediately after treatment, and 7 days after treatment, and submitted to colony forming units per milliter (CFU mL(-1)) counts. The data were submitted to ANOVA and Tukey multiple comparison tests, at a level of significance of 5 %. In the immediate post-treatment collection, group GIa showed greater bacterial reduction in comparison with GIIa, GIIb, GIIIa, GIIIb, and positive control (P < 0.05). At 7 days post-treatment, GIa showed significant bacterial reduction only in comparison with GIIIa (P < 0.05). Curcumin as sensitizer was effective by 5 min LED irradiation but not by 10 min irradiation PDT using LED light, and curcumin as PS was not effective in eliminating E. faecalis. No difference was observed for periods of irradiation.

  8. Antibacterial Efficacy of Super-Oxidized Water on Enterococcus faecalis Biofilms in Root Canal

    PubMed Central

    Zan, Recai; Alacam, Tayfun; Hubbezoglu, Ihsan; Tunc, Tutku; Sumer, Zeynep; Alici, Oguzhan

    2016-01-01

    Background The success of endodontic treatment depends on a few crucial factors. One of these factors is the complete chemomechanic preparation of root canal against various bacteria. In particular, the effect of resistant bacteria may cause intense pain with flare-up and formation of periapical lesions. Therefore, the strong effect of irrigants plays an important role in terms of the complete elimination of these bacteria to achieve long-term successful treatment. Objectives The aim of this study was to investigate the antibacterial effects of super-oxidized water (SPO) in root canals infected with Enterococcus faecalis biofilms. Methods One hundred twenty single-root, premolar teeth were selected. Initially, the teeth were prepared and then disinfected. E. faecalis were inoculated and kept at 37°C for 24 hours in the root canals. The re-inoculation procedure was repeated on the first, fourth, seventh, and tenth days. The infected root canals were divided into one negative (saline) and one positive (sodium hypochlorite) control group and four experimental groups (super-oxidized water: 1, 2, 3, or 5 minutes) (n = 20). Paper points were placed in the root canals to control and evaluate the biofilm formation. Biofilms were counted on blood agar plates, and data was evaluated and statistically analyzed using one-way ANOVA and Tukey’s test. Results Although sodium hypochlorite (NaOCl) showed no statistically significant difference when compared with three and five minutes of SPO irrigation (P > 0.05), NaOCl showed statistically significant differences among all other groups (P < 0.05). Conclusions Super-oxidized water indicated a remarkable and similar bactericidal effect to that of traditional NaOCl against E. faecalis biofilms. In terms of successful endodontic treatment approaches, super-oxidized water may be used as an effective irrigation solution in clinics. PMID:27800142

  9. Genome-Wide Identification of Small RNAs in the Opportunistic Pathogen Enterococcus faecalis V583

    PubMed Central

    Shioya, Kouki; Michaux, Charlotte; Kuenne, Carsten; Hain, Torsten; Verneuil, Nicolas; Budin-Verneuil, Aurélie; Hartsch, Thomas; Hartke, Axel; Giard, Jean-Christophe

    2011-01-01

    Small RNA molecules (sRNAs) are key mediators of virulence and stress inducible gene expressions in some pathogens. In this work we identify sRNAs in the Gram positive opportunistic pathogen Enterococcus faecalis. We characterized 11 sRNAs by tiling microarray analysis, 5′ and 3′ RACE-PCR, and Northern blot analysis. Six sRNAs were specifically expressed at exponential phase, two sRNAs were observed at stationary phase, and three were detected during both phases. Searches of putative functions revealed that three of them (EFA0080_EFA0081 and EFB0062_EFB0063 on pTF1 and pTF2 plasmids, respectively, and EF0408_EF04092 located on the chromosome) are similar to antisense RNA involved in plasmid addiction modules. Moreover, EF1097_EF1098 shares strong homologies with tmRNA (bi-functional RNA acting as both a tRNA and an mRNA) and EF2205_EF2206 appears homologous to 4.5S RNA member of the Signal Recognition Particle (SRP) ribonucleoprotein complex. In addition, proteomic analysis of the ΔEF3314_EF3315 sRNA mutant suggests that it may be involved in the turnover of some abundant proteins. The expression patterns of these transcripts were evaluated by tiling array hybridizations performed with samples from cells grown under eleven different conditions some of which may be encountered during infection. Finally, distribution of these sRNAs among genome sequences of 54 E. faecalis strains was assessed. This is the first experimental genome-wide identification of sRNAs in E. faecalis and provides impetus to the understanding of gene regulation in this important human pathogen. PMID:21912655

  10. Genome-wide identification of small RNAs in the opportunistic pathogen Enterococcus faecalis V583.

    PubMed

    Shioya, Kouki; Michaux, Charlotte; Kuenne, Carsten; Hain, Torsten; Verneuil, Nicolas; Budin-Verneuil, Aurélie; Hartsch, Thomas; Hartke, Axel; Giard, Jean-Christophe

    2011-01-01

    Small RNA molecules (sRNAs) are key mediators of virulence and stress inducible gene expressions in some pathogens. In this work we identify sRNAs in the gram positive opportunistic pathogen Enterococcus faecalis. We characterized 11 sRNAs by tiling microarray analysis, 5' and 3' RACE-PCR, and Northern blot analysis. Six sRNAs were specifically expressed at exponential phase, two sRNAs were observed at stationary phase, and three were detected during both phases. Searches of putative functions revealed that three of them (EFA0080_EFA0081 and EFB0062_EFB0063 on pTF1 and pTF2 plasmids, respectively, and EF0408_EF04092 located on the chromosome) are similar to antisense RNA involved in plasmid addiction modules. Moreover, EF1097_EF1098 shares strong homologies with tmRNA (bi-functional RNA acting as both a tRNA and an mRNA) and EF2205_EF2206 appears homologous to 4.5S RNA member of the Signal Recognition Particle (SRP) ribonucleoprotein complex. In addition, proteomic analysis of the ΔEF3314_EF3315 sRNA mutant suggests that it may be involved in the turnover of some abundant proteins. The expression patterns of these transcripts were evaluated by tiling array hybridizations performed with samples from cells grown under eleven different conditions some of which may be encountered during infection. Finally, distribution of these sRNAs among genome sequences of 54 E. faecalis strains was assessed. This is the first experimental genome-wide identification of sRNAs in E. faecalis and provides impetus to the understanding of gene regulation in this important human pathogen.

  11. Antibacterial Efficacy of Aqueous Ozone in Root Canals Infected by Enterococcus faecalis

    PubMed Central

    Hubbezoglu, Ihsan; Zan, Recai; Tunc, Tutku; Sumer, Zeynep

    2014-01-01

    Background: In endodontics, the elimination of resistant bacteria such as Enterococcus faecalis plays an important role for treatment success in root canals. Therefore, new alternative irrigants (instead of sodium hypochlorite) have been researched to achieve ideal endodontic treatment. Objectives: The aim of the present study was to evaluate and to compare the antibacterial effect of aqueous ozone with different concentrations and techniques of application (manual and ultrasonic) against E. faecalis in human root canals. Patients and Methods: Eighty single-root mandibular premolar teeth were selected, prepared and sterilized. E. faecalis was incubated in the root canals and kept at 37°C for 24 h. The teeth were divided into four main groups each has 20 members: NaOCl (positive control) group; 8 ppm aqueous ozone group; 12 ppm aqueous ozone group; and 16 ppm aqueous ozone group. While half of the specimens were disinfected with aqueous ozone by manual technique, the other half was disinfected with the aqueous ozone by ultrasonic technique. Conventional irrigation technique was simultaneously applied with ultrasonic vibration that was produced by VDW.ULTRA device. The disinfection procedures were performed for 180 s to ensure standardization of all the working groups. Paper points (placed in the root canals before and after the disinfection procedures) were transferred to Eppendorf tubes containing 0.5 mL of brain heart infusion broth. Then, 50 μL of the suspension was inoculated onto broth agar media. Microbial colonies were counted, and the data were evaluated statistically using 2-way analysis of variance (ANOVA) and Tukey tests. Results: Although the antibacterial effect of 16 ppm aqueous ozone using a manual technique had an insufficient effect, its ultrasonic application technique resulted in complete disinfection in the root canals. Conclusions: The bactericidal activity of high concentration of aqueous ozone combined with ultrasonic application technique

  12. Antibacterial Efficacy of Aqueous Ozone in Root Canals Infected by Enterococcus faecalis.

    PubMed

    Hubbezoglu, Ihsan; Zan, Recai; Tunc, Tutku; Sumer, Zeynep

    2014-07-01

    In endodontics, the elimination of resistant bacteria such as Enterococcus faecalis plays an important role for treatment success in root canals. Therefore, new alternative irrigants (instead of sodium hypochlorite) have been researched to achieve ideal endodontic treatment. The aim of the present study was to evaluate and to compare the antibacterial effect of aqueous ozone with different concentrations and techniques of application (manual and ultrasonic) against E. faecalis in human root canals. Eighty single-root mandibular premolar teeth were selected, prepared and sterilized. E. faecalis was incubated in the root canals and kept at 37°C for 24 h. The teeth were divided into four main groups each has 20 members: NaOCl (positive control) group; 8 ppm aqueous ozone group; 12 ppm aqueous ozone group; and 16 ppm aqueous ozone group. While half of the specimens were disinfected with aqueous ozone by manual technique, the other half was disinfected with the aqueous ozone by ultrasonic technique. Conventional irrigation technique was simultaneously applied with ultrasonic vibration that was produced by VDW.ULTRA device. The disinfection procedures were performed for 180 s to ensure standardization of all the working groups. Paper points (placed in the root canals before and after the disinfection procedures) were transferred to Eppendorf tubes containing 0.5 mL of brain heart infusion broth. Then, 50 μL of the suspension was inoculated onto broth agar media. Microbial colonies were counted, and the data were evaluated statistically using 2-way analysis of variance (ANOVA) and Tukey tests. Although the antibacterial effect of 16 ppm aqueous ozone using a manual technique had an insufficient effect, its ultrasonic application technique resulted in complete disinfection in the root canals. The bactericidal activity of high concentration of aqueous ozone combined with ultrasonic application technique showed efficacy similar to that of 5.25% NaOCl in root canals.

  13. In vivo broiler experiments to assess anti-Campylobacter jejuni activity of a live Enterococcus faecalis strain.

    PubMed

    Robyn, J; Rasschaert, G; Hermans, D; Pasmans, F; Heyndrickx, M

    2013-01-01

    Bacterial gastroenteritis caused by thermotolerant Campylobacter species, mainly Campylobacter jejuni, has been the most reported zoonotic disease in many developed countries in recent years. Reducing Campylobacter shedding on the farm could result in a reduction of the number of campylobacteriosis cases. In 2 independent broiler seeder experiments, in which broiler chickens were orally inoculated with 2 amounts of Enterococcus faecalis MB 5259, we established whether a live E. faecalis strain was capable of reducing cecal Campylobacter colonization in broiler chickens. In previous in vitro experiments it has been demonstrated that this E. faecalis MB 5259 displays anti-Campylobacter activity. The effect of pH and bile salts on E. faecalis MB 5259 showed that growth and survival of E. faecalis MB 5259 can be impaired during passage through the gastrointestinal tract of broiler chickens. Despite these results E. faecalis MB 5259 was capable of colonizing the broiler ceca. Contrary to the in vitro experiments, in which E. faecalis MB 5259 inhibited C. jejuni MB 4185 growth, no inhibition was observed in the in vivo experiments independent of the inoculum size.

  14. Bacteriocin protein BacL1 of Enterococcus faecalis is a peptidoglycan D-isoglutamyl-L-lysine endopeptidase.

    PubMed

    Kurushima, Jun; Hayashi, Ikue; Sugai, Motoyuki; Tomita, Haruyoshi

    2013-12-27

    Enterococcus faecalis strains are commensal bacteria in humans and other animals, and they are also the causative agent of opportunistic infectious diseases. Bacteriocin 41 (Bac41) is produced by certain E. faecalis clinical isolates, and it is active against other E. faecalis strains. Our genetic analyses demonstrated that the extracellular products of the bacL1 and bacA genes, which are encoded in the Bac41 operon, coordinately express the bacteriocin activity against E. faecalis. In this study, we investigated the molecular functions of the BacL1 and BacA proteins. Immunoblotting and N-terminal amino acid sequence analysis revealed that BacL1 and BacA are secreted without any processing. The coincidental treatment with the recombinant BacL1 and BacA showed complete bacteriocin activity against E. faecalis, but neither BacL1 nor BacA protein alone showed the bacteriocin activity. Interestingly, BacL1 alone demonstrated substantial degrading activity against the cell wall fraction of E. faecalis in the absence of BacA. Furthermore, MALDI-TOF MS analysis revealed that BacL1 has a peptidoglycan D-isoglutamyl-L-lysine endopeptidase activity via a NlpC/P60 homology domain. These results collectively suggest that BacL1 serves as a peptidoglycan hydrolase and, when BacA is present, results in the lysis of viable E. faecalis cells.

  15. Enterococcus faecalis Bearing Aggregation Substance Is Resistant to Killing by Human Neutrophils despite Phagocytosis and Neutrophil Activation

    PubMed Central

    Rakita, Robert M.; Vanek, Natalie N.; Jacques-Palaz, Karen; Mee, Mee; Mariscalco, M. Michele; Dunny, Gary M.; Snuggs, Mark; Van Winkle, W. Barry; Simon, Scott I.

    1999-01-01

    Enterococcus faecalis aggregation substance (AS) mediates efficient bacterium-bacterium contact to facilitate plasmid exchange as part of a bacterial sex pheromone system. We have previously determined that AS promotes direct, opsonin-independent binding of E. faecalis to human neutrophils (PMNs) via complement receptor type 3 and other receptors on the PMN surface. We have now examined the functional consequences of this bacterium-host cell interaction. AS-bearing E. faecalis was phagocytosed and internalized by PMNs, as determined by deconvolution fluorescence microscopy. However, these bacteria were not killed by PMNs, and internalized bacteria excluded propidium iodide, indicating intact bacterial membranes. Resistance to killing occurred despite activation of PMNs, as indicated by an increase in both functional and total surface Mac-1 expression, shedding of l-selectin, and an increase in PMN extracellular superoxide and phagosomal oxidant production. Deconvolution fluorescence microscopy also revealed that phagosomes containing AS-bearing bacteria were markedly larger than phagosomes containing opsonized E. faecalis, suggesting that some modification of phagosomal maturation may be involved in AS-induced resistance to killing. PMN phagosomal pH was significantly higher after ingestion of nonopsonized AS-bearing E. faecalis than after that of opsonized bacteria. The novel ability of AS to promote intracellular survival of E. faecalis inside PMNs suggests that AS may be a virulence factor used by strains of E. faecalis. PMID:10531268

  16. Microbial shifts in the porcine distal gut in response to diets supplemented with Enterococcus Faecalis as alternatives to antibiotics

    PubMed Central

    Li, Pinghua; Niu, Qing; Wei, Qingtian; Zhang, Yeqiu; Ma, Xiang; Kim, Sung Woo; Lin, Mingxin; Huang, Ruihua

    2017-01-01

    Gut microbiota plays an important role in host health and nutrient digestion of animals. Probiotics have become one of effective alternatives to antibiotics enhancing animal health and performance through modulating gut microbiota. Previously, our research demonstrated that dietary Enterococcus Faecalis UC-100 substituting antibiotics enhanced growth and health of weaned pigs. To investigate the alterations of microbiota in the distal gut of pigs fed E. faecalis UC-100 substituting antibiotics, this study assessed fecal microbiota in pigs from different dietary treatments: the basal diet group, the E. faecalis group, and the antibiotic group on d 0, 14, and 28 of feeding through 16 S rRNA sequencing. Twenty-one phyla and 137 genera were shared by all pigs, whereas 12 genera were uniquely identified in the E. faecalis group on d 14 and 28. Bacterial abundance and diversity in the E. faecalis group, bacterial diversity in the antibiotic group, especially abundances of Fibrobacteres phylum and 12 genera in the E. faecalis group and antibiotics group were lower than that in the basal diet group on d 28. These results showed that microbial shifts in the porcine gut in response to diets containing E. faecalis were similar to the response to which containing antibiotics. PMID:28165001

  17. The effects of sodium hypochlorite and chlorhexidine irrigants on the antibacterial activities of alkaline media against Enterococcus faecalis.

    PubMed

    Ma, Jinglei; Tong, Zhongchun; Ling, Junqi; Liu, Hongyan; Wei, Xi

    2015-07-01

    Sodium hypochlorite (NaOCl), chlorhexidine (CHX) and calcium hydroxide are common intracanal medicaments. The present study aimed to evaluate the effects of NaOCl and CHX on the antibacterial activities of alkaline media against Enterococcus faecalis. The survival rates of planktonic and biofilm E. faecalis were evaluated by plate counts after 1 min of pretreatment with NaOCl and CHX, and time-kill assays were then used to assess subsequent pH alkaline challenges. Dead and living cells in the E. faecalis biofilm were assessed with SYTO 9 and PI staining in combination with confocal laser scanning microscopy following exposure to NaOCl or CHX and subsequent alkaline challenges by common root canal irrigation and dressing procedures. One minute of pretreatment with 2% CHX, 0.2% CHX, or 5.25% NaOCl in combination with a subsequent alkaline challenge significantly decreased planktonic E. faecalis survival rates, but pretreatment with 1% NaOCl did not. The E. faecalis biofilm survival rates were reduced in the subsequent alkaline challenge following CHX pretreatment but gradually increased following NaOCl pretreatment. Similarly, CLSM analysis revealed that the greatest proportions of dead E. faecalis cells in the biofilms were presented in the CHX and alkaline treatment group. CHX might be more effective in improving the antibacterial activities of alkaline root canal medicaments against E. faecalis than NaOCl during routine root canal therapy procedures. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Prevalence of Virulence Factors and Vancomycin-resistant Genes among Enterococcus faecalis and E. faecium Isolated from Clinical Specimens

    PubMed Central

    NASAJ, Mona; MOUSAVI, Seyed Masoud; HOSSEINI, Seyed Mostafa; ARABESTANI, Mohammad Reza

    2016-01-01

    Background: The aim of this study was to determine the occurrence of virulence determinants and vancomycin-resistant genes among Enterococcus faecalis and E. faecium obtained from various clinical sources. Methods: The study was performed on the 280 enterococcal isolated from clinical specimens in Hamadan hospitals, western Iran in 2012–14. Antibiotic susceptibility testing was performed using disk diffusion and Minimal Inhibitory Concentration (MIC) methods. The presence of vancomycin-resistant genes and virulence genes was investigated using PCR. Results: Totally 280 enterococcal isolates were identified as follows: E. faecalis (62.5%), E. faecium (24%) and Enterococcus spp (13.5%). The results of antibiotic susceptibility testing showed that resistance rates to vancomycin and teicoplanin in E. faecalis and E. faecium isolates were 5% and 73%, respectively. Of Sixty vancomycin-resistant Enterococci strains, fifty-one isolates were identified as E. faecium (VREfm) and nine as E. faecalis (VREfs). Prevalence of esp, hyl, and asa1 genes were determined as 82%, 71.6%, and 100%, respectively in E. faecium strains; and 78%, 56/6%, and 97%, respectively in E. faecalis strains. Conclusion: The increased frequency of VREF, as seen with rapid rise in the number of vanA isolates should be considered in infection control practices. PMID:27648425

  19. The mazEF toxin-antitoxin system as an attractive target in clinical isolates of Enterococcus faecium and Enterococcus faecalis.

    PubMed

    Soheili, Sara; Ghafourian, Sobhan; Sekawi, Zamberi; Neela, Vasantha Kumari; Sadeghifard, Nourkhoda; Taherikalani, Morovat; Khosravi, Afra; Ramli, Ramliza; Hamat, Rukman Awang

    2015-01-01

    The toxin-antitoxin (TA) system is a regulatory system where two sets of genes encode the toxin and its corresponding antitoxin. In this study, the prevalence of TA systems in independently isolated clinical isolates of Enterococcus faecium and Enterococcus faecalis was determined, the dominant TA system was identified, different virulence genes in E. faecium and E. faecalis were surveyed, the level of expression of the virulence and TA genes in normal and stress conditions was determined, and finally their associations with the TA genes were defined. Remarkably, the analysis demonstrated higBA and mazEF in all clinical isolates, and their locations were on chromosomes and plasmids, respectively. On the other hand, a quantitative analysis of TA and virulence genes revealed that the expression level in both genes is different under normal and stress conditions. The results obtained by anti-mazF peptide nucleic acids demonstrated that the expression level of virulence genes had decreased. These findings demonstrate an association between TA systems and virulence factors. The mazEF on the plasmids and the higBA TA genes on the chromosomes of all E. faecium and E. faecalis strains were dominant. Additionally, there was a decrease in the expression of virulence genes in the presence of anti-mazF peptide nucleic acids. Therefore, it is suggested that mazEF TA systems are potent and sensitive targets in all E. faecium and E. faecalis strains.

  20. High-level aminoglycoside resistance in Enterococcus faecalis and Enterococcus faecium causing invasive infection: Twelve-year surveillance in the Minami Ibaraki Area.

    PubMed

    Osuka, Hanako; Nakajima, Jun; Oishi, Tsuyoshi; Funayama, Yasunori; Ebihara, Tsugio; Ishikawa, Hiroichi; Saito, Kazuto; Koganemaru, Hiroshi; Hitomi, Shigemi

    2016-01-01

    We examined prevalence of high-level aminoglycoside resistance (HLAR) in Enterococcus faecalis and Enterococcus faecium causing invasive infection in the Minami Ibaraki Area. Ten strains of both species each, recovered from the blood or the cerebrospinal fluid between 2003 and 2014, were randomly selected every year. High-level resistance to gentamicin (HLR-GM) and streptomycin (HLR-SM) was detected in 34% (41 of 120 strains) and 18% (21) of E. faecalis and 9% (11) and 39% (48) of E. faecium, respectively. In comparisons of the proportions among three four-year periods, HLR-SM among E. faecium was significantly lower in the 2011-2014 period. All strains with HLR-GM were positive for the aac(6')-Ie-aph(2″)-Ia gene. The ant(6')-Ia gene was detected in all with HLR-SM except for one E. faecalis strain. The present study showed that prevalence of HLR-GM among E. faecalis and E. faecium causing invasive infection in this area was nearly equivalent to that described in previous studies in Japan and that proportions of strains with HLAR did not vary during the study period except for that of HLR-SM among E. faecium.

  1. Induction of ermAMR from a Clinical Strain of Enterococcus faecalis by 16-Membered-Ring Macrolide Antibiotics

    PubMed Central

    Oh, Tae-Gwon; Kwon, Ae-Ran; Choi, Eung-Chil

    1998-01-01

    We cloned the MLSB resistance determinant by PCR from a clinical isolate of Enterococcus faecalis 373, which is induced more strongly by a 16-membered-ring macrolide, tylosin, than by erythromycin. To elucidate the molecular basis of resistance of E. faecalis 373, we analyzed the cloned gene, designated ermAMR, by site-directed mutagenesis and reporter gene assay. Our results showed that an arginine-to-cysteine change in the seventh codon of the putative leader peptide endowed tylosin with resistance inducibility and that TAAA duplication enabled the control region to express the downstream methylase gene at a drastically increased level. PMID:9791136

  2. New Combinations of Mutations in VanD-Type Vancomycin-Resistant Enterococcus faecium, Enterococcus faecalis, and Enterococcus avium Strains ▿

    PubMed Central

    Depardieu, F.; Foucault, M.-L.; Bell, J.; Dubouix, A.; Guibert, M.; Lavigne, J.-P.; Levast, M.; Courvalin, P.

    2009-01-01

    We studied the clinical isolates Enterococcus faecium NEF1, resistant to high levels of vancomycin (MIC, 512 μg/ml) and teicoplanin (MIC, 64 μg/ml); Enterococcus faecium BM4653 and BM4656 and Enterococcus avium BM4655, resistant to moderate levels of vancomycin (MIC, 32 μg/ml) and to low levels of teicoplanin (MIC, 4 μg/ml); and Enterococcus faecalis BM4654, moderately resistant to vancomycin (MIC, 16 μg/ml) but susceptible to teicoplanin (MIC, 0.5 μg/ml). The strains were distinct, were constitutively resistant via the synthesis of peptidoglycan precursors ending in d-alanyl-d-lactate, and harbored a chromosomal vanD gene cluster that was not transferable. New mutations were found in conserved domains of VanSD: at T170I near the phosphorylation site in NEF1, at V67A at the membrane surface in BM4653, at G340S in the G2 ATP-binding domain in BM4655, in the F domain in BM4656 (a 6-bp insertion), and in the G1 and G2 domains of BM4654 (three mutations). The mutations resulted in constitutivity, presumably through the loss of the phosphatase activity of the sensor. The chromosomal Ddl d-Ala:d-Ala ligase had an IS19 copy in NEF1, a mutation in the serine (S185F) or near the arginine (T289P) involved in d-Ala1 binding in BM4653 or BM4655, respectively, and a mutation next to the lysine (P180S) involved in d-Ala2 binding in BM4654, leading to the production of an impaired enzyme. In BM4653 vanYD, a new insertion sequence, ISEfa9, belonging to the IS3 family, resulted in the absence of d,d-carboxypeptidase activity. Strain BM4656 had a functional d-Ala:d-Ala ligase, associated with high levels of both VanXD and VanYD activities, and is the first example of a VanD-type strain with a functional Ddl enzyme. Study of these five clinical isolates, displaying various assortments of mutations, confirms that all VanD-type strains isolated so far have undergone mutations in the vanSD or vanRD gene, leading to constitutive resistance, but that the Ddl host ligase is not

  3. Biochemical characterization of an anti-Candida factor produced by Enterococcus faecalis

    PubMed Central

    2012-01-01

    Background Because Candida albicans is resistant to several antifungal antibiotics, there is a need to identify other less toxic natural products, particularly antimicrobial proteins, peptides or bacteriocin like inhibitory substances. An attempt has been made to purify and characterise an anti-Candida compound produced by Enterococcus faecalis. Results An anti-Candida protein (ACP) produced by E. faecalis active against 8 C. albicans strains was characterised and partially purified. The ACP showed a broad-spectrum activity against multidrug resistant C. albicans MTCC 183, MTCC 7315, MTCC 3958, NCIM 3557, NCIM 3471 and DI. It was completely inactivated by treatment with proteinase K and partially by pronase E. The ACP retained biological stability after heat-treatment at 90°C for 20 min, maintained activity over a pH range 6–10, and remained active after treatment with α-amylase, lipase, organic solvents, and detergents. The antimicrobial activity of the E. faecalis strain was found exclusively in the extracellular filtrate produced in the late logarithmic growth phase. The highest activity (1600 AU mL-1) against C. albicans MTCC 183 was recorded at 48 h of incubation, and activity decreased thereafter. The peptide showed very low haemagglutination and haemolytic activities against human red blood cells. The antimicrobial substance was purified by salt-fractionation and chromatography. Partially purified ACP had a molecular weight of approximately 43 KDa in Tricine-PAGE analysis. The 12 amino acid N terminal sequence was obtained by Edman degradation. The peptide was de novo sequenced by ESI-MS, and the deduced combined sequence when compared to other bacteriocins and antimicrobial peptide had no significant sequence similarity. Conclusions The inhibitory activity of the test strain is due to the synthesis of an antimicrobial protein. To our knowledge, this is the first report on the isolation of a promising non-haemolytic anti-Candida protein from E

  4. Good Bugs vs Bad Bugs: Evaluation of Inhibitory Effect of Selected Probiotics against Enterococcus faecalis.

    PubMed

    Bohora, Aarti A; Kokate, Sharad R

    2017-04-01

    The main goal of endodontics is the prevention of apical periodontitis. This is due to the presence of persistent pathogenic microorganisms, such as Enterococcus faecalis, and its ability to directly cause acute and chronic inflammation in the periapical tissues. Lactobacillus has been shown to promote health in the intestines as well as to inhibit the growth of certain problematic oral bacteria. This study explores shifting the established paradigm of endodontic treatment, which has focused on eliminating all bacteria from the canal system and on elimination of the problematic bacteria through introducing probiotics. A preliminary work was performed to evaluate the possible effectiveness of probiotics in preventing the growth of E. faecalis. Two probiotic cultures Lactobacillus plantarum ATCC 8041 and Lactobacillus rhamnosus ATCC 7408 were selected to check their antimicrobial activity against E. faecalis ATCC 29212 by two methods: agar cup/well diffusion method and deferred antagonism test. Agar cup method: A total of 0.5 mL of requisite test pathogen culture was inoculated into 20 mL of molten sterile Mueller and Hinton agar and cooled to 45 ± 2°C. Circular wells of diameter 10 mm were punched in each of the poured plates. Appropriately diluted test samples were added to the above-punched wells. The plates were incubated upright position at 37°C for 24 hours in aerobic conditions. Postincubation, zone of inhibition was measured. The cell-free supernatant of Lactobacillus species was also evaluated for antimicrobial activity. Deferred antagonism test: The test probiotic strain was standardized to 0.1 optical density (OD) at 600 nm and inoculated in a 1 cm wide diametric streak across the surface of trypticase soy agar + yeast extract + calcium carbonate (TSYCa) agar using a sterile cotton swab. Then, the plate agar containing the test strain was incubated at 37°C for 24 hours under aero-philic condition and then standardized to 0.1 OD at 600 nm for overnight

  5. Complete Genome Sequence of Enterococcus faecalis Strain P8-1 Isolated from Wild Magellanic Penguin (Spheniscus magellanicus) Feces on the South Coast of Brazil

    PubMed Central

    Prichula, Janira; Campos, Fabricio Souza; Pereira, Rebeca Inhoque; Cardoso, Leonardo Almansa; Wachholz, Guilherme Raffo; Pieta, Luiza; Mariot, Roberta Fogliatto; de Moura, Tiane Martin; Tavares, Maurício; d’Azevedo, Pedro Alves; Frazzon, Ana Paula Guedes

    2016-01-01

    Enterococcus faecalis strains have a ubiquitous nature that allows them to survive in different niches. Studies involving enterococci isolated from marine animals are scarce. Therefore, in this study, we report the complete genome sequence of E. faecalis strain P8-1 isolated from feces of a Magellanic penguin on the south coast of Brazil. PMID:26769928

  6. Substantivity of Ag-Ca-Si mesoporous nanoparticles on dentin and its ability to inhibit Enterococcus faecalis.

    PubMed

    Fan, Wei; Wu, Yujie; Ma, Tengjiao; Li, Yanyun; Fan, Bing

    2016-01-01

    The main purpose of this study was to investigate the substantivity of Ag-Ca-Si mesoporous nanoparticles (Ag-MCSNs) on dentin and its residual antibacterial effects against Enterococcus faecalis. Ag-MCSNs were fabricated and characterized, ion release profile and pH were tested, and the ability to inhibit planktonic E. faecalis as well as the cytotoxicity was evaluated. Dentin slices were medicated with Ca(OH)2 paste, 2 % chlorhexidine gel and Ag-MCSNs paste for 7 days and then irrigated. Dentin slices were then immersed in E. faecalis suspension for 6 days and then transferred to fresh brain heart infusion solution. The optical density value within 10 h after immersing and transferring were measured and compared among groups. Results indicated that Ag-MCSNs showed high pH, sustained Ag(+)-Ca(2+)-SiO3 (2-) ion release, and high substantivity on dentin. The Ag-MCSNs exhibited strong antibacterial effects against planktonic E. faecalis and much better residual inhibition effects against E. faecalis growth on dentin than Ca(OH)2 paste (P < 0.05). The Ag-MCSNs showed excellent antibacterial ability against E. faecalis and high substantivity on dentin, which might be developed to a new effective intra-canal medicament for human teeth.

  7. Characteristics of an environmental strain, Enterococcus faecalis CECT7121, and its effects as additive on craft dry-fermented sausages.

    PubMed

    Sparo, M; Nuñez, G G; Castro, M; Calcagno, M L; García Allende, M A; Ceci, M; Najle, R; Manghi, M

    2008-06-01

    Lactic acid bacteria are the most adequate microorganisms for natural preservation of food. In the present work, the strain of Enterococcus faecalis CECT7121 was employed in the manufacture of craft dry-fermented sausages and its performance as a biopreservative was analysed. This strain is devoid of the genes for haemolysin and gelatinase and does not produce biogenic amines. It is sensitive to almost all the antibiotics tested and opsonophagocytic assays showed that it is devoid of a capsule. This strain had a high LD50 (10(11)CFU ml(-1)) in mice. No statistical differences were found between control and sausages inoculated with E. faecalis CECT7121 regarding the production of lactic acid, pH variation over time, reaching a minimum pH value of 5.1, and sensory analysis in both series. Sausages inoculated with E. faecalis CECT7121 had lower viable counts of Enterobacteriaceae, Staphylococcus aureus and other Gram-positive cocci at the end of fermentation and 7 days and no viable enterobacteria and S. aureus were recovered at the end of drying. E. faecalis CECT7121 did not affect the growth of Lactobacillus spp. but it displaced the autochthonous populations of enterococci. E. faecalis CECT7121 was recovered in each time point as assessed by its inhibitory activity on Listeria monocytogenes and S. aureus. These results would indicate that the addition of E. faecalis CECT7121 during the manufacture of craft dry-fermented sausages offers an interesting alternative for biopreservation.

  8. [The effect of a combined nanoparticulate/calcium hydroxide medication on the biofilm of Enterococcus faecalis in starvation phase].

    PubMed

    Zhang, Fu-hua; Li, Mao; Wei, Zhi-jun; Zhao, Bing

    2016-02-01

    To evaluate the efficacy of Ca(OH)2 with a silver nanoparticle suspension to eliminate the biofilm of Enterococcus faecalis (E. faecalis) in starvation phase. The biofilm models of E.faecalis in the starvation phase were built in vitro with 256 extracted human single-rooted teeth, and the methods of plate culture count and crystal violet biofilm assay were applied to determine the effect of the inhibition of different intracanal medicament (silver nanoparticle with calcium hydroxide, silver nanoparticle alone, calcium hydroxide alone ) to the biofilm of E. faecalis in starvation phase at 1 and 7 days. The negative control group was treated with sterile water only. Statistical analysis was carried out with SPSS 13.0 software package. The inhibitory effect of Ca(OH)2+nanosilver on the biofilms of E. faecalis was found more significant than that of silver nanoparticle alone and calcium hydroxide alone at 1 and 7 days, and silver nanoparticle alone was more effective than calcium hydroxide alone. No difference in antimicrobial properties was observed between the two time points in the Ca(OH)2+silver nanoparticle group and silver nanoparticle group, while higher antimicrobial efficacy was observed in the Ca(OH)2 group after 7 days than 1 day. Silver nanoparticle with calcium hydroxide has an obvious inhibitory effect on the biofilm of E.faecalis in the starvation phase.

  9. Local Genetic Patterns within a Vancomycin-Resistant Enterococcus faecalis Clone Isolated in Three Hospitals in Portugal

    PubMed Central

    Novais, Carla; Coque, Teresa M.; Sousa, João Carlos; Baquero, Fernando; Peixe, Luisa

    2004-01-01

    Eight pulsed-field gel electrophoresis subtypes and six Tn1546 variants were identified among Enterococcus faecalis isolates of a single clone recovered in three geographically separate Portuguese hospitals. Some clonal subtypes were found in particular hospitals, and Tn1546 variants were either widespread or confined to some of them. We also report on the first Tn1546 transposon containing an ISEf1 insertion. PMID:15328141

  10. Critical Importance of In Vivo Amoxicillin and Cefotaxime Concentrations for Synergy in Treatment of Experimental Enterococcus faecalis Endocarditis

    PubMed Central

    Join-Lambert, Olivier; Mainardi, Jean-Luc; Cuvelier, Catherine; Dautrey, Sophie; Farinotti, Robert; Fantin, Bruno; Carbon, Claude

    1998-01-01

    The synergy between amoxicillin and cefotaxime against two strains of Enterococcus faecalis (JH2-2 and 6370) in vitro and in rabbit endocarditis was investigated. In vitro synergy was obtained only when amoxicillin concentrations were below the MBC and when cefotaxime concentrations were above 1 μg/ml. No synergy was observed in vivo, because of the short period of time during which these pharmacologic requirements were achieved. PMID:9527811

  11. Basal levels of (p)ppGpp in Enterococcus faecalis: the magic beyond the stringent response.

    PubMed

    Gaca, Anthony O; Kajfasz, Jessica K; Miller, James H; Liu, Kuanqing; Wang, Jue D; Abranches, Jacqueline; Lemos, José A

    2013-09-24

    The stringent response (SR), mediated by the alarmone (p)ppGpp, is a conserved bacterial adaptation system controlling broad metabolic alterations necessary for survival under adverse conditions. In Enterococcus faecalis, production of (p)ppGpp is controlled by the bifunctional protein RSH (for "Rel SpoT homologue"; also known as RelA) and by the monofunctional synthetase RelQ. Previous characterization of E. faecalis strains lacking rsh, relQ, or both revealed that RSH is responsible for activation of the SR and that alterations in (p)ppGpp production negatively impact bacterial stress survival and virulence. Despite its well-characterized role as the effector of the SR, the significance of (p)ppGpp during balanced growth remains poorly understood. Microarrays of E. faecalis strains producing different basal amounts of (p)ppGpp identified several genes and pathways regulated by modest changes in (p)ppGpp. Notably, expression of numerous genes involved in energy generation were induced in the rsh relQ [(p)ppGpp(0)] strain, suggesting that a lack of basal (p)ppGpp places the cell in a "transcriptionally relaxed" state. Alterations in the fermentation profile and increased production of H2O2 in the (p)ppGpp(0) strain substantiate the observed transcriptional changes. We confirm that, similar to what is seen in Bacillus subtilis, (p)ppGpp directly inhibits the activity of enzymes involved in GTP biosynthesis, and complete loss of (p)ppGpp leads to dysregulation of GTP homeostasis. Finally, we show that the association of (p)ppGpp with antibiotic survival does not relate to the SR but rather relates to basal (p)ppGpp pools. Collectively, this study highlights the critical but still underappreciated role of basal (p)ppGpp pools under balanced growth conditions. Drug-resistant bacterial infections continue to pose a significant public health threat by limiting therapeutic options available to care providers. The stringent response (SR), mediated by the accumulation of

  12. Epidemiological alteration in pathogens found in ground meat in Iran: unexpected predominance of vancomycin-resistant Enterococcus faecalis.

    PubMed

    Sadeghifard, Nourkhoda; Kazemian, Hossein; Mohebi, Reza; Sekawi, Zamberi; Khosravi, Afra; Valizadeh, Nasrin; Ghafourian, Sobhan

    2015-01-01

    Colonization of the human and animal intestinal tract with potential pathogenic bacteria is correlated with the risk of contamination of food products. The current study analyzed the prevalence of Enterococcus faecalis and Escherichia coli O157H7 in ground meat in Ilam, Iran. Both index organisms were identified following standard food microbiological methods. For E. faecalis, the susceptibility to vancomycin was tested, and PCR was used to check for the vanA gene. E. faecalis was present in all 24 ground meat samples, with no E. coli O157H7 detected in samples. The analysis showed the presence of the vanA gene in 5/24 vancomycin resistant enterococci. In conclusion, this study for the first time demonstrates the presence of vancomycin-resistant enterococci in ground meat in Iran. This observation warrants further epidemiologic investigation and should be followed up in the future.

  13. Evaluation of a novel chromogenic agar medium for isolation and differentiation of vancomycin-resistant Enterococcus faecium and Enterococcus faecalis isolates.

    PubMed

    Ledeboer, Nathan A; Das, Kingshuk; Eveland, Michael; Roger-Dalbert, Céline; Mailler, Sandrine; Chatellier, Sonia; Dunne, William Michael

    2007-05-01

    The development of reliable and rapid methods for the identification of patients colonized with vancomycin-resistant enterococci (VRE) is central to the containment of this agent within a hospital environment. To this end, we evaluated a prototype chromogenic agar medium (VRE-BMX; bioMérieux, Marcy l'Etoile, France) used to recover VRE from clinical specimens. This medium can also identify isolated colonies as either vancomycin-resistant Enterococcus faecium or Enterococcus faecalis, based on distinct colony colors. We compared the performance of VRE-BMX with bile esculin azide agar supplemented with vancomycin (BEAV). For this study, 147 stool samples were plated on each test medium and examined after 24 and 48 h of incubation. At 24 h, the sensitivity and specificity of each medium were as follows: BEAV, 90.9% and 89.9%, respectively; VRE-BMX, 96.4% and 96.6%, respectively. The positive predictive values (PPV) of VRE-BMX and BEAV at 24 h were 89.8% and 80.7%, respectively. VRE-BMX provided the identification of 10 isolates of vancomycin-resistant E. faecalis and 4 isolates of vancomycin-resistant E. faecium that were not recovered by BEAV. Further, VRE-BMX was capable of identifying patients colonized with both E. faecium and E. faecalis, a feature useful for infection control purposes that is not a function of BEAV. In terms of the recovery of vancomycin-resistant E. faecium and E. faecalis, the sensitivity and PPV were as follows: BEAV, 75.7% and 74.6%, respectively; VRE-BMX, 95.5% and 91.3%, respectively. In this initial evaluation, we found that VRE-BMX provided improved recovery of VRE from stool specimens, with the added advantage of being able to differentiate between vancomycin-resistant E. faecalis and E. faecium. Extending the incubation period beyond 24 h did not significantly improve the recovery of VRE and resulted in decreased specificity.

  14. Atomic force microscopy visualization of injuries in Enterococcus faecalis surface caused by Er,Cr:YSGG and diode lasers

    PubMed Central

    López-Jiménez, Lidia; Viñas, Miguel; Vinuesa, Teresa

    2015-01-01

    Aim: To visualize by Atomic Force Microscopy the alterations induced on Enterococcus. faecalis surface after treatment with 2 types of laser: Erbium chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser and Diode laser. Material and Methods: Bacterial suspensions from overnight cultures of E. faecalis were irradiated during 30 seconds with the laser-lights at 1 W and 2 W of power, leaving one untreated sample as control. Surface alterations on treated E. faecalis were visualized by Atomic Force Microscopy (AFM) and its surface roughness determined. Results: AFM imaging showed that at high potency of laser both cell morphology and surface roughness resulted altered, and that several cell lysis signs were easily visualized. Surface roughness clearly increase after the treatment with Er,Cr:YSGG at 2W of power, while the other treatments gave similar values of surface roughness. The effect of lasers on bacterial surfaces visualized by AFM revealed drastic alterations. Conclusions: AFM is a good tool to evaluate surface injuries after laser treatment; and could constitute a measure of antimicrobial effect that can complete data obtained by determination of microbial viability. Key words:Atomic force microscopy, Er,Cr:YSGG laser, diode laser, Enterococcus faecalis, surface roughness. PMID:25475770

  15. Fine-Tuned Transcriptional Regulation of Malate Operons in Enterococcus faecalis

    PubMed Central

    Mortera, Pablo; Espariz, Martín; Suárez, Cristian; Repizo, Guillermo; Deutscher, Josef; Alarcón, Sergio; Blancato, Víctor

    2012-01-01

    In Enterococcus faecalis, the mae locus is constituted by two putative divergent operons, maePE and maeKR. The first operon encodes a putative H+/malate symporter (MaeP) and a malic enzyme (MaeE) previously shown to be essential for malate utilization in this bacterium. The maeKR operon encodes two putative proteins with significant similarity to two-component systems involved in sensing malate and activating its assimilation in bacteria. Our transcriptional and genetic assays showed that maePE and maeKR are induced in response to malate by the response regulator MaeR. In addition, we observed that both operons were partially repressed in the presence of glucose. Accordingly, the cometabolism of this sugar and malate was detected. The binding of the complex formed by CcpA and its corepressor P-Ser-HPr to a cre site located in the mae region was demonstrated in vitro and explains the carbon catabolite repression (CCR) observed for the maePE operon. However, our results also provide evidence for a CcpA-independent CCR mechanism regulating the expression of both operons. Finally, a biomass increment of 40 or 75% was observed compared to the biomass of cells grown only on glucose or malate, respectively. Cells cometabolizing both carbon sources exhibit a higher rate of glucose consumption and a lower rate of malate utilization. The growth improvement achieved by E. faecalis during glucose-malate cometabolism might explain why this microorganism employs different regulatory systems to tightly control the assimilation of both carbon sources. PMID:22247139

  16. Gentamicin induces efaA expression and biofilm formation in Enterococcus faecalis.

    PubMed

    Kafil, Hossein Samadi; Mobarez, Ashraf Mohabati; Moghadam, Mehdi Forouzandeh; Hashemi, Zahra Sadat; Yousefi, Mehdi

    2016-03-01

    Enterococci have been ranked among the leading causes of nosocomial bacteremia and urinary tract infection. This study aimed to investigate the effect of ampicillin, vancomycin, gentamicin and ceftizoxime on biofilm formation and gene expression of colonization factors on Enterococcus faecalis. Twelve clinical isolates of E. faecalis were used to investigate the effect of antibiotics on biofilm formation and gene expression of efaA, asa1, ebpA, esp and ace. Flow system assay and Microtiter plates were used for biofilm assay. Two hundred clinical isolates were used for confirming the effect of antibiotics on biofilm formation. Ampicillin, vancomycin and ceftizoxime did not have any significant effect on biofilm formation, but gentamicin induced biofilm formation in 89% of isolates. In twelve selected isolate gentamicin increased expression of esp (+50.9%) and efaA (+33.9%) genes and reduced or maintained expression of others (asa1:-47.4%, ebpA: 0, ace:-19.2%). Vancomycin increased expression of esp (+89.1%) but reduced the others (asa1: -34.9%, ebpA:-11%, ace:-30%, efaA:-60%). Ceftizoxime increased slightly ebpA (+19.7%) and reduced others (asa1:-66.2%, esp:-35%, ace:-28.1%, efaA:-38.4%). and ampicillin strongly increased expression of ace (+231%), esp (+131%) and ebpA (+83%) but reduced others (asa1:-85.5%, efaA:-47.4%). The findings of the present study showed that antibiotics may have a role in biofilm formation and sustainability of enterococci, especially in case of gentamicin. efaA gene may have an important role, especially in antibiotic induced biofilm formation by gentamicin. Experiments with efaA mutants are needed to investigate the exact effect of efaA on biofilm formation with antibiotic induced cells.

  17. Drosophila Host Model Reveals New Enterococcus faecalis Quorum-Sensing Associated Virulence Factors

    PubMed Central

    Teixeira, Neuza; Varahan, Sriram; Gorman, Matthew J.; Palmer, Kelli L.; Zaidman-Remy, Anna; Yokohata, Ryoji; Nakayama, Jiro; Hancock, Lynn E.; Jacinto, António; Gilmore, Michael S.; de Fátima Silva Lopes, Maria

    2013-01-01

    Enterococcus faecalis V583 is a vancomycin-resistant clinical isolate which belongs to the hospital-adapted clade, CC2. This strain harbours several factors that have been associated with virulence, including the fsr quorum-sensing regulatory system that is known to control the expression of GelE and SprE proteases. To discriminate between genes directly regulated by Fsr, and those indirectly regulated as the result of protease expression or activity, we compared gene expression in isogenic mutants of V583 variously defective in either Fsr quorum sensing or protease expression. Quorum sensing was artificially induced by addition of the quorum signal, GBAP, exogenously in a controlled manner. The Fsr regulon was found to be restricted to five genes, gelE, sprE, ef1097, ef1351 and ef1352. Twelve additional genes were found to be dependent on the presence of GBAP-induced proteases. Induction of GelE and SprE by GBAP via Fsr resulted in accumulation of mRNA encoding lrgAB, and this induction was found to be lytRS dependent. Drosophila infection was used to discern varying levels of toxicity stemming from mutations in the fsr quorum regulatory system and the genes that it regulates, highlighting the contribution of LrgAB and bacteriocin EF1097 to infection toxicity. A contribution of SprE to infection toxicity was also detected. This work brought to light new players in E. faecalis success as a pathogen and paves the way for future studies on host tolerance mechanisms to infections caused by this important nosocomial pathogen. PMID:23734216

  18. Development of a peptide antagonist against fsr quorum sensing of Enterococcus faecalis.

    PubMed

    Nakayama, Jiro; Yokohata, Ryoji; Sato, Mami; Suzuki, Takashi; Matsufuji, Takahisa; Nishiguchi, Kenzo; Kawai, Takeshi; Yamanaka, Yosuke; Nagata, Koji; Tanokura, Masaru; Sonomoto, Kenji

    2013-04-19

    Enterococcus faecalis fsr quorum sensing (QS) involves an 11-residue cyclic peptide named gelatinase biosynthesis-activating pheromone (GBAP) that autoinduces two pathogenicity-related extracellular proteases in a cell density-dependent fashion. To identify anti-pathogenic agents that target fsr QS signaling, peptide antagonists of GBAP were created by our unique drug design approach based on reverse alanine scanning. First of all, a receptor-binding scaffold (RBS), [Ala(4,5,6,8,9,11)]Z-GBAP, was created, in which all amino acids within the ring region of GBAP, except for two essential aromatic residues, were substituted to alanine. Next, the substituted alanine residues were changed back to the original amino acid one by one, permitting selection of those peptide combinations exhibiting increased antagonist activity. After three cycles of this reverse alanine scan, [Ala(5,9,11)]Z-GBAP was obtained as a maximally reverted peptide (MRP) holding the strongest antagonist activity. Then, the fifth residue in MRP, which is one of the critical residues to determine agonist/antagonist activity, was further modified by substituting with different types of amino acids including unnatural amino acids. As a result, [Tyr(Bzl)(5), Ala(9,11)]Z-GBAP, named ZBzl-YAA5911, showed the strongest antagonist activity [IC(50) = 26.2 nM and Kd against GBAP receptor (FsrC) = 39.4 nM]. In vivo efficacy of this peptide was assessed with an aphakic rabbit endophthalmitis model. ZBzl-YAA5911 suppressed the translocation of E. faecalis from the aqueous humor into the vitreous cavity by more than 1 order of magnitude and significantly reduced retinal damage. We propose that ZBzl-YAA5911 or its derivatives would be useful as anti-infective agents to attenuate virulence expression in this opportunistic pathogen.

  19. Transcriptomics Analysis Reveals Putative Genes Involved in Biofilm Formation and Biofilm-associated Drug Resistance of Enterococcus faecalis.

    PubMed

    Seneviratne, Chaminda J; Suriyanarayanan, Tanujaa; Swarup, Sanjay; Chia, Kuan Hui Burton; Nagarajan, Niranjan; Zhang, Chengfei

    2017-06-01

    Enterococcus faecalis is a gram-positive bacterium associated with endodontic infections and is capable of forming biofilms that can confer drug resistance to the bacterium, resulting in treatment failure. Current knowledge on E. faecalis drug resistance is of a limited and conflicting nature. The present study examined the genetic basis of E. faecalis biofilm formation and drug resistance using a RNA sequencing (RNA-Seq)-based transcriptome approach. Eighteen clinical isolates of E. faecalis were screened for their biofilm formation abilities using the crystal violet assay, colony counting, and confocal imaging. Selected isolates were then evaluated for antibiotic susceptibility in planktonic and biofilm growth modes followed by RNA-Seq analysis of E. faecalis planktonic, biofilm, and vancomycin-treated biofilm samples and Kyoto Encyclopedia of Genes and Genomes mapping in order to identify genes associated with biofilm formation and drug resistance of E. faecalis. All 18 clinical isolates retained biofilm formation ability and were classified as strong, weak, or laboratory American Type Culture Collection strainlike biofilm formers. Interestingly, both the strong and weak biofilm-forming isolates were uniformly resistant to ampicillin and vancomycin at the treated concentrations (256-4096 μg/mL). RNA-Seq analysis of these isolates identified a total of 163 and 101 differentially regulated genes in planktonic versus biofilm and vancomycin-treated biofilm versus biofilm comparisons, respectively, with significant differences in arsenic resistance operon genes arsR and arsD, sporulation regulatory gene paiA, ABC drug transporter classes, and penicillin-binding proteins. The present transcriptomic study revealed putative genes associated with E. faecalis biofilm formation and drug resistance, which will provide a foundation for improved therapeutic strategies against E. faecalis infections in the future. Copyright © 2017 American Association of Endodontists

  20. Enterococcus faecalis Endocarditis Severity in Rabbits Is Reduced by IgG Fabs Interfering with Aggregation Substance

    PubMed Central

    Schlievert, Patrick M.; Chuang-Smith, Olivia N.; Peterson, Marnie L.; Cook, Laura C. C.; Dunny, Gary M.

    2010-01-01

    Background Enterococcus faecalis is a significant cause of infective endocarditis, an infection of the heart endothelium leading to vegetation formation (microbes, fibrin, platelets, and host cells attached to underlying endothelial tissue). Our previous research determined that enterococcal aggregation substance (AS) is an important virulence factor in causation of endocarditis, although endocarditis may occur in the absence of AS production. Production of AS by E. faecalis causes the organism to form aggregates through AS binding to enterococcal binding substance. In this study, we assessed the ability of IgGs and IgG Fabs against AS to provide protection against AS+ E. faecalis endocarditis. Methodology/Principal Findings When challenged with AS+ E. faecalis, 10 rabbits actively immunized against AS+ E. faecalis developed more significant vegetations than 9 animals immunized against AS− E. faecalis, and 9/10 succumbed compared to 2/9 (p<0.005), suggesting enhanced aggregation by IgG contributes significantly to disease. IgG antibodies against AS also enhanced enterococcal aggregation as tested in vitro. In contrast, Fab fragments of IgG from rabbits immunized against purified AS, when passively administered to rabbits (6/group) immediately before challenge with AS+ E. faecalis, reduced total vegetation (endocarditis lesion) microbial counts (7.9×106 versus 2.0×105, p = 0.02) and size (40 mg versus 10, p = 0.05). In vitro, the Fabs prevented enterococcal aggregation. Conclusions/Significance The data confirm the role of AS in infective endocarditis formation and suggest that use of Fabs against AS will provide partial protection from AS+ E. faecalis illness. PMID:20957231

  1. Systems biology approach for mapping the response of human urothelial cells to infection by Enterococcus faecalis

    PubMed Central

    Dozmorov, Mikhail G; Kyker, Kimberly D; Saban, Ricardo; Shankar, Nathan; Baghdayan, Arto S; Centola, Michael B; Hurst, Robert E

    2007-01-01

    Background To better understand the response of urinary epithelial (urothelial) cells to Enterococcus faecalis, a uropathogen that exhibits resistance to multiple antibiotics, a genome-wide scan of gene expression was obtained as a time series from urothelial cells growing as a layered 3-dimensional culture similar to normal urothelium. We herein describe a novel means of analysis that is based on deconvolution of gene variability into technical and biological components. Results Analysis of the expression of 21,521 genes from 30 minutes to 10 hours post infection, showed 9553 genes were expressed 3 standard deviations (SD) above the system zero-point noise in at least 1 time point. The asymmetric distribution of relative variances of the expressed genes was deconvoluted into technical variation (with a 6.5% relative SD) and biological variation components (>3 SD above the mode technical variability). These 1409 hypervariable (HV) genes encapsulated the effect of infection on gene expression. Pathway analysis of the HV genes revealed an orchestrated response to infection in which early events included initiation of immune response, cytoskeletal rearrangement and cell signaling followed at the end by apoptosis and shutting down cell metabolism. The number of poorly annotated genes in the earliest time points suggests heretofore unknown processes likely also are involved. Conclusion Enterococcus infection produced an orchestrated response by the host cells involving several pathways and transcription factors that potentially drive these pathways. The early time points potentially identify novel targets for enhancing the host response. These approaches combine rigorous statistical principles with a biological context and are readily applied by biologists. PMID:18047719

  2. Molecular Epidemiologic Analysis of Enterococcus faecalis Isolates in Cuba by Multilocus Sequence Typing

    PubMed Central

    Kobayashi, Nobumichi; Nagashima, Shigeo

    2009-01-01

    We carried out the first study of Enterococcus faecalis clinical isolates in Cuba by multilocus sequence typing linking the molecular typing data with the presence of virulence determinants and the antibiotic resistance genes. A total of 23 E. faecalis isolates recovered from several clinic sources and geographic areas of Cuba during a period between 2000 and 2005 were typed by multilocus sequence typing. Thirteen sequence types (STs) including five novel STs were identified, and the ST 64 (clonal complex [CC] 8), ST 6 (CC2), ST 21(CC21), and ST 16 (CC58) were found in more than one strain. Sixty-seven percent of STs corresponded to STs reported previously in Spain, Poland, and The Netherlands, and other STs (ST115, ST64, ST6, and ST40) were genetically close to those detected in the United States. Prevalence of both antimicrobial resistance genes [aac(6′)-aph(2″), aph(3′), ant(6), ant(3″)(9), aph(2″)-Id, aph(2″)-Ic, erm(B), erm(A), erm(C), mef(A), tet(M), and tet(L)] and virulence genes (agg, gelE, cylA, esp, ccf, and efaAfs) were examined by polymerase chain reaction. Aminoglycoside resistance genes aac(6′)-Ie-aph(2″)-Ia, aph(3′), ant(6), ant(3″)(9) were more frequently detected in ST6, ST16, ST23, ST64, and ST115. The multidrug resistance was distributed to all STs detected, except for ST117 and singleton ST225. The presence of cyl gene was specifically linked to the ST64 and ST16. Presence of the esp, gel, and agg genes was not specific to any particular ST. This research provided the first insight into the population structure of E. faecalis in Cuba, that is, most Cuban strains were related to European strains, whereas others to U.S. strains. The CC2, CC21, and CC8, three of the biggest CCs in the world, were evidently circulating in Cuba, associated with multidrug resistance and virulence traits. PMID:19857135

  3. Antibacterial Efficacy of Octenisept, Alexidine, Chlorhexidine, and Sodium Hypochlorite against Enterococcus faecalis Biofilms.

    PubMed

    Bukhary, Sundus; Balto, Hanan

    2017-04-01

    The purpose of this study was to evaluate the antibacterial effectiveness of Octenisept (OCT; Schülke & Mayr GmBH, Norderstedt, Germany), 1% alexidine (ALX) (Santa Cruz Biotechnology, Inc, Santa Cruz, CA), and 2% chlorhexidine (CHX) against Enterococcus faecalis biofilm using confocal laser scanning microscopy. Root dentin discs were prepared from extracted human teeth, sterilized, and inoculated with E. faecalis strain (ATCC 29212) to establish 3-week-old biofilm model. Infected dentin discs were exposed to OCT (n = 20), 1% ALX (n = 20), and 2% CHX (n = 20) for 10 minutes. Dentin discs (n = 15) exposed to 5.25% sodium hypochlorite (NaOCl) were used as a positive control, whereas specimens exposed to saline (n = 15) were used as a negative control. After exposure, the dentin discs were stained with fluorescent LIVE/DEAD BacLight dye (Invitrogen Molecular Probes, Eugene, OR) and analyzed with confocal laser scanning microscopy to determine the proportion of dead cells in the biofilm. Statistical analysis was performed using the Kruskal-Wallis and Mann-Whitney U tests (P < .05). The highest proportion of dead cells was found in the 5.25% NaOCl group (94.14%; range, 92.30%-98.20%) compared with the experimental groups (P < .05). A significantly greater proportion of dead cells was found in the OCT group (74.14%; range, 70.03%-78.96%) compared with the 1% ALX and 2% CHX groups (P < .05). The proportion of dead cells was 43.89% (range, 24.86%-55.63%) and 42.78% (range, 25.45%-55.06%) in the 1% ALX and 2% CHX groups, respectively, with no statistical significant difference between the 2 groups (P > .05). NaOCl had significantly greater antimicrobial activity against E. faecalis biofilms compared with OCT, CHX, and ALX. OCT was more effective than CHX and ALX. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  4. Biofilms of Enterococcus faecalis and Enterococcus faecium isolated from the processing of ricotta and the control of these pathogens through cleaning and sanitization procedures.

    PubMed

    da Silva Fernandes, Meg; Kabuki, Dirce Yorika; Kuaye, Arnaldo Yoshiteru

    2015-05-04

    The biofilm formation of Enterococcus faecalis and Enterococcus faecium isolated from the processing of ricotta on stainless steel coupons was evaluated, and the effect of cleaning and sanitization procedures in the control of these biofilms was determined. The formation of biofilms was observed while varying the incubation temperature (7, 25 and 39°C) and time (0, 1, 2, 4, 6 and 8 days). At 7°C, the counts of E. faecalis and E. faecium were below 2 log10 CFU/cm(2). For the temperatures of 25 and 39°C, after 1 day, the counts of E. faecalis and E. faecium were 5.75 and 6.07 log10 CFU/cm(2), respectively, which is characteristic of biofilm formation. The tested sanitation procedures a) acid-anionic tensioactive cleaning, b) anionic tensioactive cleaning+sanitizer and c) acid-anionic tensioactive cleaning+sanitizer were effective in removing the biofilms, reducing the counts to levels below 0.4 log10 CFU/cm(2). The sanitizer biguanide was the least effective, and peracetic acid was the most effective. These studies revealed the ability of enterococci to form biofilms and the importance of the cleaning step and the type of sanitizer used in sanitation processes for the effective removal of biofilms.

  5. CRISPR-Cas and Restriction-Modification Act Additively against Conjugative Antibiotic Resistance Plasmid Transfer in Enterococcus faecalis

    PubMed Central

    Price, Valerie J.; Huo, Wenwen; Sharifi, Ardalan

    2016-01-01

    ABSTRACT Enterococcus faecalis is an opportunistic pathogen and a leading cause of nosocomial infections. Conjugative pheromone-responsive plasmids are narrow-host-range mobile genetic elements (MGEs) that are rapid disseminators of antibiotic resistance in the faecalis species. Clustered regularly interspaced short palindromic repeat (CRISPR)-Cas and restriction-modification confer acquired and innate immunity, respectively, against MGE acquisition in bacteria. Most multidrug-resistant E. faecalis isolates lack CRISPR-Cas and possess an orphan locus lacking cas genes, CRISPR2, that is of unknown function. Little is known about restriction-modification defense in E. faecalis. Here, we explore the hypothesis that multidrug-resistant E. faecalis strains are immunocompromised. We assessed MGE acquisition by E. faecalis T11, a strain closely related to the multidrug-resistant hospital isolate V583 but which lacks the ~620 kb of horizontally acquired genome content that characterizes V583. T11 possesses the E. faecalis CRISPR3-cas locus and a predicted restriction-modification system, neither of which occurs in V583. We demonstrate that CRISPR-Cas and restriction-modification together confer a 4-log reduction in acquisition of the pheromone-responsive plasmid pAM714 in biofilm matings. Additionally, we show that the orphan CRISPR2 locus is functional for genome defense against another pheromone-responsive plasmid, pCF10, only in the presence of cas9 derived from the E. faecalis CRISPR1-cas locus, which most multidrug-resistant E. faecalis isolates lack. Overall, our work demonstrated that the loss of only two loci led to a dramatic reduction in genome defense against a clinically relevant MGE, highlighting the critical importance of the E. faecalis accessory genome in modulating horizontal gene transfer. Our results rationalize the development of antimicrobial strategies that capitalize upon the immunocompromised status of multidrug-resistant E. faecalis

  6. Chlorine disinfection of Pseudomonas aeruginosa, total coliforms, Escherichia coli and Enterococcus faecalis: revisiting reclaimed water regulations.

    PubMed

    Coronel-Olivares, Claudia; Reyes-Gómez, Lidia María; Hernández-Muñoz, Aurelio; Martínez-Falcón, Ana Paola; Vázquez-Rodríguez, Gabriela A; Iturbe, Ulises

    2011-01-01

    Pathogenic organisms can be transmitted orally through drinking water or through skin and mucosae by both direct and indirect contact, and their presence in water thus has a negative impact on public health. In wastewater treatment plants (WWTP), water is disinfected to inactivate pathogens. The quantification of several microbial indicators in aquatic systems is required to estimate the biological quality of such systems. So far, coliform bacteria have been used as traditional indicators world-wide. This study has assessed the resistance of total coliforms, Escherichia coli, Pseudomonas aeruginosa and Enterococcus faecalis to three dosages of sodium hypochlorite (NaClO) at two exposure times. The bacteria were isolated from secondary effluents of a WWTP located in Hidalgo, Mexico. The results show that the number of colony-forming units of all studied bacterial types decreased when both the NaClO concentration and exposure times increased. However, they were not eliminated. The inclusion of the species Pseudomonas aeruginosa in regulations for treated wastewater quality as a new indicator is highly recommended due to its importance as an opportunistic pathogen. The detection of this species along with the traditional organisms could be particulary significant for reclaimed water to be used with direct human contact.

  7. Heat-Killed Enterococcus faecalis EF-2001 Ameliorates Atopic Dermatitis in a Murine Model.

    PubMed

    Choi, Eun-Ju; Iwasa, Masahiro; Han, Kwon-Il; Kim, Wan-Jae; Tang, Yujiao; Hwang, Young Joung; Chae, Jeong Ryong; Han, Weon Cheol; Shin, Yu-Su; Kim, Eun-Kyung

    2016-03-05

    Recent reports have shown the immunomodulatory effect of heat-killed lactic acid bacteria. Atopic dermatitis (AD) is an allergic skin disease, caused by immune dysregulation among other factors. The aim of this study was to assess the effect of heat-killed Enterococcus faecalis EF-2001 (EF-2001) on AD. We established an in vivo AD model by repeated local exposure of Dermatophagoides farinae extract (DFE; house dust mite extract) and 2,4-dinitrochlorobenzene (DNCB) to the ears of mice. After oral administration of EF-2001 for four weeks, the epidermal and dermal ear thickness, mast cell infiltration, and serum immunoglobulin levels were measured. In addition, the gene expression levels of pathogenic cytokines in the ears, lymph nodes, and splenocytes were assayed. EF-2001 attenuated AD symptoms based on the ear thickness, histopathological analysis, and serum immunoglobulin levels. Moreover, EF-2001 decreased the DFE/DNCB-induced expression of various pathogenic cytokines in the ears, lymph nodes, and splenocytes. These results suggest that EF-2001 has therapeutic potential in the treatment of AD owing to its immunomodulatory effects.

  8. Crystal structure of enterococcus faecalis sly A-like transcriptional factor.

    SciTech Connect

    Wu, R.; Zhang, R.; Zagnitko, O.; Dementieva, I.; Maltsev, N.; Watson, J. D.; Laskowski, R.; Gornicki, P.; Joachimiak, A.; Univ. of Chicago; European Bioinformatics Inst.

    2003-05-30

    The crystal structure of a SlyA transcriptional regulator at 1.6 {angstrom} resolution is presented, and structural relationships between members of the MarR/SlyA family are discussed. The SlyA family, which includes SlyA, Rap, Hor, and RovA proteins, is widely distributed in bacterial and archaeal genomes. Current evidence suggests that SlyA-like factors act as repressors, activators, and modulators of gene transcription. These proteins have been shown to up-regulate the expression of molecular chaperones, acid-resistance proteins, and cytolysin, and down-regulate several biosynthetic enzymes. The structure of SlyA from Enterococcus faecalis, determined as a part of an ongoing structural genomics initiative (www.mcsg.anl.gov), revealed the same winged helix DNA-binding motif that was recently found in the MarR repressor from Escherichia coli and the MexR repressor from Pseudomonas aeruginosa, a sequence homologue of MarR. Phylogenetic analysis of the MarR/SlyA family suggests that Sly is placed between the SlyA and MarR subfamilies and shows significant sequence similarity to members of both subfamilies.

  9. Adaptation of Enterococcus faecalis to Daptomycin Reveals an Ordered Progression to Resistance

    PubMed Central

    Miller, Corwin; Kong, Jiayi; Tran, Truc T.; Arias, Cesar A.; Saxer, Gerda

    2013-01-01

    With increasing numbers of hospital-acquired antibiotic resistant infections each year and staggering health care costs, there is a clear need for new antimicrobial agents, as well as novel strategies to extend their clinical efficacy. While genomic studies have provided a wealth of information about the alleles associated with adaptation to antibiotics, they do not provide essential information about the relative importance of genomic changes, their order of appearance, or potential epistatic relationships between adaptive changes. Here we used quantitative experimental evolution of a single polymorphic population in continuous culture with whole-genome sequencing and allelic frequency measurements to study daptomycin (DAP) resistance in the vancomycin-resistant clinical pathogen Enterococcus faecalis S613. Importantly, we sustained both planktonic and nonplanktonic (i.e., biofilm) populations in coculture as the concentration of antibiotic was raised, facilitating the development of more ecological complexity than is typically observed in laboratory evolution. Quantitative experimental evolution revealed a clear order and hierarchy of genetic changes leading to resistance, the signaling and metabolic pathways responsible, and the relative importance of these mutations to the evolution of DAP resistance. Despite the relative simplicity of this ex vivo approach compared to the ecological complexity of the human body, we showed that experimental evolution allows for rapid identification of clinically relevant adaptive molecular pathways and new targets for drug design in pathogens. PMID:23959318

  10. Mechanisms of Allosteric Activation and Inhibition of the Deoxyribonucleoside Triphosphate Triphosphohydrolase from Enterococcus faecalis*♦

    PubMed Central

    Vorontsov, Ivan I.; Wu, Ying; DeLucia, Maria; Minasov, George; Mehrens, Jennifer; Shuvalova, Ludmilla; Anderson, Wayne F.; Ahn, Jinwoo

    2014-01-01

    EF1143 from Enterococcus faecalis, a life-threatening pathogen that is resistant to common antibiotics, is a homo-tetrameric deoxyribonucleoside triphosphate (dNTP) triphosphohydrolase (dNTPase), converting dNTPs into the deoxyribonucleosides and triphosphate. The dNTPase activity of EF1143 is regulated by canonical dNTPs, which simultaneously act as substrates and activity modulators. Previous crystal structures of apo-EF1143 and the protein bound to both dGTP and dATP suggested allosteric regulation of its enzymatic activity by dGTP binding at four identical allosteric sites. However, whether and how other canonical dNTPs regulate the enzyme activity was not defined. Here, we present the crystal structure of EF1143 in complex with dGTP and dTTP. The new structure reveals that the tetrameric EF1143 contains four additional secondary allosteric sites adjacent to the previously identified dGTP-binding primary regulatory sites. Structural and enzyme kinetic studies indicate that dGTP binding to the first allosteric site, with nanomolar affinity, is a prerequisite for substrate docking and hydrolysis. Then, the presence of a particular dNTP in the second site either enhances or inhibits the dNTPase activity of EF1143. Our results provide the first mechanistic insight into dNTP-mediated regulation of dNTPase activity. PMID:24338016

  11. The Enterococcus faecalis cytolysin: a novel toxin active against eukaryotic and prokaryotic cells.

    PubMed

    Coburn, Phillip S; Gilmore, Michael S

    2003-10-01

    The enterococcal cytolysin, a two-peptide lytic system, is a divergent relative of a large family of toxins and bacteriocins secreted by pathogenic and non-pathogenic Gram-positive bacteria. This family includes the lantibiotics and streptolysin S. The enterococcal cytolysin is of interest because its activities enhance enterococcal virulence in infection models and, in epidemiological studies, it has been associated with patient mortality. The cytolysin is lethal for a broad range of prokaryotic and eukaryotic cells, and this activity requires two non-identical, post-translationally modified peptides. The smaller of the two peptides also plays a role in a quorum-sensing autoinduction of the cytolysin operon. As a trait that is present in particularly virulent strains of Enterococcus faecalis, including strains that are resistant to multiple antibiotics, it serves as a model for testing the value of developing new virulence-targeting therapeutics. Further, because of the interest in small membrane active peptides as therapeutics themselves, studies of the molecular structure/activity relationships for the cytolysin peptides are providing insights into the physical basis for prokaryotic versus eukaryotic cell targeting.

  12. Enterococcus faecalis causing delayed spondylodiscitis in a case with retained intraspinal bullet

    PubMed Central

    Aiyer, Siddharth N.; Kanna, Rishi; Reddy, Srikanth; Rajasekaran, Shanmuganathan

    2016-01-01

    Delayed presentations have been reported following gunshot wounds (GSW) with retained intraspinal bullets due to migration of projectile or lead intoxication. We report on the rare occurrence of delayed pyogenic spondylodiscitis and neurological dysfunction following injury from low velocity GSW to the spine with a retained projectile. A 55-year-old male presented 4 months following GSW to the abdomen which resulted in colonic injury and L5 fracture. The patient was treated initially with ileo-transverse anastomosis, antibiotics, without retrieval of the bullet. He developed low back pain, claudication 4 months following GSW and investigations suggested a pyogenic spondylodiscitis at L5–S1. The patient was treated with surgical debridement of infective focus and stabilisation with definitive fusion being performed after an interval of 14 days. The biopsy of the lesion confirmed findings of spondylodiscitis and the culture isolated Enterococcus faecalis species. The patient was treated with antibiotics as per sensitivity and made an uneventful recovery over 4 weeks. The follow-up radiographs showed satisfactory healing at final follow up of 24 months. GSW with colonic perforation have higher incidence of infective complications however majority to these occur in the early postoperative period. This case report demonstrates the possibility of late onset presentation due to spinal infection occurring following colonic perforation with retained intraspinal bullet. PMID:28097252

  13. An ABC Transporter Is Required for Secretion of Peptide Sex Pheromones in Enterococcus faecalis

    PubMed Central

    Varahan, Sriram; Harms, Nathan; Gilmore, Michael S.; Tomich, John M.

    2014-01-01

    ABSTRACT Enterococci are leading causes of hospital-acquired infection in the United States and continue to develop resistances to new antibiotics. Many Enterococcus faecalis isolates harbor pheromone-responsive plasmids that mediate horizontal transfer of even large blocks of chromosomal genes, resulting in hospital-adapted strains over a quarter of whose genomes consist of mobile elements. Pheromones to which the donor cells respond derive from lipoprotein signal peptides. Using a novel bacterial killing assay dependent on the presence of sex pheromones, we screened a transposon mutant library for functions that relate to the production and/or activity of the effector pheromone. Here we describe a previously uncharacterized, but well-conserved, ABC transporter that contributes to pheromone production. Using three distinct pheromone-dependent mating systems, we show that mutants defective in expressing this transporter display a 5- to 6-order-of-magnitude reduction in conjugation efficiency. In addition, we demonstrate that the ABC transporter mutant displays an altered biofilm architecture, with a significant reduction in biofilm biomass compared to that of its isogenic parent, suggesting that pheromone activity also influences biofilm development. The conservation of this peptide transporter across the Firmicutes suggests that it may also play an important role in cell-cell communication in other species within this important phylum. PMID:25249282

  14. Heat-Killed Enterococcus faecalis EF-2001 Ameliorates Atopic Dermatitis in a Murine Model

    PubMed Central

    Choi, Eun-Ju; Iwasa, Masahiro; Han, Kwon-Il; Kim, Wan-Jae; Tang, Yujiao; Hwang, Young Joung; Chae, Jeong Ryong; Han, Weon Cheol; Shin, Yu-Su; Kim, Eun-Kyung

    2016-01-01

    Recent reports have shown the immunomodulatory effect of heat-killed lactic acid bacteria. Atopic dermatitis (AD) is an allergic skin disease, caused by immune dysregulation among other factors. The aim of this study was to assess the effect of heat-killed Enterococcus faecalis EF-2001 (EF-2001) on AD. We established an in vivo AD model by repeated local exposure of Dermatophagoides farinae extract (DFE; house dust mite extract) and 2,4-dinitrochlorobenzene (DNCB) to the ears of mice. After oral administration of EF-2001 for four weeks, the epidermal and dermal ear thickness, mast cell infiltration, and serum immunoglobulin levels were measured. In addition, the gene expression levels of pathogenic cytokines in the ears, lymph nodes, and splenocytes were assayed. EF-2001 attenuated AD symptoms based on the ear thickness, histopathological analysis, and serum immunoglobulin levels. Moreover, EF-2001 decreased the DFE/DNCB-induced expression of various pathogenic cytokines in the ears, lymph nodes, and splenocytes. These results suggest that EF-2001 has therapeutic potential in the treatment of AD owing to its immunomodulatory effects. PMID:26959058

  15. Study Comparing the Effectiveness of Chlorhexidine, Calcium Hydroxide and Linezolid Based Medicaments Against Enterococcus Faecalis

    PubMed Central

    Pavaskar, Rajdeep; Chalakkal, Paul; Krishnan, Ramesh; Sirikonda, Saritha; Vasepalli, Madhu; Venkataramana, Pammi

    2014-01-01

    Purpose: This study evaluated the efficacy of 2% chlorhexidine (CX), calcium hydroxide (CH), Vitapex® (VP), linezolid (LZ), a combination of LZ with CH (LC) against Enterococcus faecalis (EF). Study Design: EF strains were mixed with peptone water and the turbidity was adjusted to the McFarland’s turbidity standard tube No: 0.5. The inoculum obtained was used to make lawn cultures on the agar plates. A total of 30 agar plates were prepared, such that each plate had five wells containing the five medicaments. The plates were incubated and evaluated for zones of inhibition after intervals of 24 hours and 72 hours. The results were statistically evaluated by paired t-test, ANOVA and Post-hoc analysis using Tukey’s HSD. Results: The difference between values of the zones of inhibition around various medicaments after 24 hours and 72 hours was found to be statistically significant. A comparison between the five groups after 24 hours or 72 hours showed that each group differed significantly from the rest of the groups. Conclusions: LC had the greatest effectiveness against EF, followed by LZ, CX, VP and CH. PMID:24783147

  16. The TIR Domain Containing Locus of Enterococcus faecalis Is Predominant among Urinary Tract Infection Isolates and Downregulates Host Inflammatory Response

    PubMed Central

    Kraemer, Thomas Daniel; Quintanar Haro, Orlando Daniel; Domann, Eugen; Chakraborty, Trinad; Tchatalbachev, Svetlin

    2014-01-01

    Based on Toll/interleukin-1 receptor (TIR) domain structure homology, we detected a previously uncharacterized gene encoding for a TIR domain containing protein (Tcp) in the genome of Enterococcus faecalis. We assigned this gene the name tcpF (as in Tcp of E. faecalis). Screening of E. faecalis samples revealed that tcpF is more common in isolates from urinary tract infections (UTIs) than in human faecal flora. tcpF alleles showed moderate single nucleotide polymorphism (SNP) among UTI isolates. Infection of mouse RAW264.7 macrophages with a tcpF knock-out mutant led to elevated cytokine response compared to the isogenic wild type E. faecalis strain. In silico analysis predicted significant tertiary structure homology to the TIR domain of human TLR1 (TLR1-TIR). When transiently expressed in cultured eukaryotic cells, TcpF caused suppression of TLR2-dependent NF-κB activation suggesting for TcpF a role as a factor in E. faecalis that benefits colonization by modulating the host's immune responses. PMID:25147569

  17. Antimicrobial activity of some essential oils against oral multidrug-resistant Enterococcus faecalis in both planktonic and biofilm state

    PubMed Central

    Benbelaïd, Fethi; Khadir, Abdelmounaïm; Abdoune, Mohamed Amine; Bendahou, Mourad; Muselli, Alain; Costa, Jean

    2014-01-01

    Objective To evaluate some essential oils in treatment of intractable oral infections, principally caused by biofilm of multidrug-resistant Enterococcus faecalis (E. faecalis), such as persistent endodontic infections in which their treatment exhibits a real challenge for dentists. Methods Ten chemically analyzed essential oils by gas chromatography-mass spectrometry were evaluated for antimicrobial activity against sensitive and resistant clinical strains of E. faecalis in both planktonic and biofilm state using two methods, disk diffusion and broth micro-dilution. Results Studied essential oils showed a good antimicrobial activity and high ability in E. faecalis biofilm eradication, whether for sensitive or multidrug-resistant strains, especially those of Origanum glandulosum and Thymbra capitata with interesting minimum inhibitory concentration, biofilm inhibitory concentration, and biofilm eradication concentration values which doesn't exceed 0.063%, 0.75%, and 1.5%, respectively. Conclusions Findings of this study indicate that essential oils extracted from aromatic plants can be used in treatment of intractable oral infections, especially caused by biofilm of multidrug-resistant E. faecalis. PMID:25182948

  18. Construction of an Enterococcus faecalis Tn917-Mediated-Gene-Disruption Library Offers Insight into Tn917 Insertion Patterns

    PubMed Central

    Garsin, Danielle A.; Urbach, Jonathan; Huguet-Tapia, Jose C.; Peters, Joseph E.; Ausubel, Frederick M.

    2004-01-01

    Sequencing the insertion sites of 8,865 Tn917 insertions in Enterococcus faecalis strain OG1RF identified a hot spot in the replication terminus region corresponding to 6% of the genome where 65% of the transposons had inserted. In E. faecalis, Tn917 preferentially inserted at a 29-bp consensus sequence centered on TATAA, a 5-bp sequence that is duplicated during insertion. The regional insertion site preference at the chromosome terminus was not observed in another low-G+C gram-positive bacterium, Listeria monocytogenes, although the consensus insertion sequence was the same. The 8,865 Tn917 insertion sites sequenced in E. faecalis corresponded to only ∼610 different open reading frames, far fewer than the predicted number of 2,400, assuming random insertion. There was no significant preference in orientation of the Tn917 insertions with either transcription or replication. Even though OG1RF has a smaller genome than strain V583 (2.8 Mb versus 3.2 Mb), the only E. faecalis strain whose sequence is in the public domain, over 10% of the Tn917 insertions appear to be in a OG1RF-specific sequence, suggesting that there are significant genomic differences among E. faecalis strains. PMID:15489440

  19. Characterization of lead-resistant river isolate Enterococcus faecalis and assessment of its multiple metal and antibiotic resistance.

    PubMed

    Aktan, Yasin; Tan, Sema; Icgen, Bulent

    2013-06-01

    Contamination of surface waters has a direct impact on the public health of entire communities. Microorganisms inhabiting contaminated surface waters have developed mechanisms of coping with a variety of toxic metals and drugs. Investigations were carried out to isolate and identify lead-resistant bacteria from the river Kızılırmak along the city of Kırıkkale, Turkey. Of the 33 lead-resistant isolates, one isolate with a minimal inhibitory concentration of 1,200 mg L(-1) was isolated and identified as Enterococcus faecalis by using biochemical tests and 16S rRNA sequencing. Lead-resistant E. faecalis isolate was found out to be resistant to other heavy metals like aluminum, lithium, barium, chromium, iron, silver, tin, nickel, zinc, and strontium and to drugs like amikacin, aztreonam, and gentamicin. E. faecalis harbored four plasmids with the molecular sizes of 1.58, 3.06, 22.76, and 28.95 kb. Plasmid profile analyses of cured derivatives revealed that the lead resistance ability of E. faecalis was still existing despite the elimination of all the plasmids. Moreover, the antibiotic resistance pattern of the cured derivatives did not demonstrate any change from the parental strain. Our findings indicated that the lead resistance genes of E. faecalis were located on the chromosomal DNA rather than the plasmid.

  20. The effect of gelatinase production of Enterococcus faecalis on adhesion to dentin after irrigation with various endodontic irrigants.

    PubMed

    Guneser, Mehmet Burak; Eldeniz, Ayce Unverdi

    2016-12-01

    Objectives: The aim of this study was to evaluate whether the gelatinase production ability of Enterococcus faecalis provides any advantage on adhesion of this bacterium to dentin treated with various irrigants and their combinations. Materials and methods: Standardized dentin discs were randomly divided into five groups (n = 20): group 1: 2.5% sodium hypochlorite (NaOCl), group 2: 2% chlorhexidine (CHX), group 3: NaOCl + Saline + CHX, group 4: NaOCl + EDTA + NaOCl, group 5: QMix. After incubation of dentin discs with irrigants, each group was divided into two subgroups (n = 10) according to the bacterial strains used; a gelatinase-producing and a gelatinase-deficient strain of E. faecalis. After incubation of the discs with the bacterial suspensions aerobically for 48 h, XTT assay was conducted for bacterial adherence evaluation. Data were statistically analyzed by ANOVA and Tukey's HSD tests (p = .05). Results: Gelatinase-producing E. faecalis adhered to dentin was significantly more than gelatinase-deficient E. faecalis in all test groups (p < .05). Adherence to CHX-treated dentin was lower than to the surfaces treated with other irrigants, alone or in combination (p < .05). These differences were significant except for comparisons with QMix for gelatinase-producing bacteria (p < .05). Conclusions: Gelatinase production of E. faecalis may be an important factor for bacterial adhesion. The addition of CHX to the irrigation regimen resulted in fewer adhered bacteria to dentin. QMix was not as effective as CHX in terms of bacterial adhesion prevention.

  1. Effects of storage temperature on tyramine production by Enterococcus faecalis R612Z1 in water-boiled salted ducks.

    PubMed

    Liu, Fang; Du, Lihui; Wu, Haihong; Wang, Daoying; Zhu, Yongzhi; Geng, Zhiming; Zhang, Muhan; Xu, Weimin

    2014-10-01

    Tyramine production by Enterococcus faecalis R612Z1 in water-boiled salted ducks was evaluated during storage at different temperatures. The results showed that E. faecalis R612Z1 could produce tyramine in meat samples when the storage temperature was no less than 4°C. The E. faecalis R612Z1 counts of the meat samples reached 10(8) CFU/g on day 7 at 4°C and on day 4 at 10°C. However, the tyramine content of the meat samples stored at 10°C increased to 23.73 μg/g (on day 10), which was greater than the level in the samples stored at 4°C (7.56 μg/g). Reverse transcription quantitative PCR detection of the expression level of the tyrDC gene in E. faecalis R612Z1 in the meat samples revealed no significant changes at different storage temperatures. Thus, the changes in tyramine production of E. faecalis R612Z1 may be due to the different enzymatic activities at different storage temperatures.

  2. The TIR Domain Containing Locus of Enterococcus faecalis Is Predominant among Urinary Tract Infection Isolates and Downregulates Host Inflammatory Response.

    PubMed

    Kraemer, Thomas Daniel; Quintanar Haro, Orlando Daniel; Domann, Eugen; Chakraborty, Trinad; Tchatalbachev, Svetlin

    2014-01-01

    Based on Toll/interleukin-1 receptor (TIR) domain structure homology, we detected a previously uncharacterized gene encoding for a TIR domain containing protein (Tcp) in the genome of Enterococcus faecalis. We assigned this gene the name tcpF (as in Tcp of E. faecalis). Screening of E. faecalis samples revealed that tcpF is more common in isolates from urinary tract infections (UTIs) than in human faecal flora. tcpF alleles showed moderate single nucleotide polymorphism (SNP) among UTI isolates. Infection of mouse RAW264.7 macrophages with a tcpF knock-out mutant led to elevated cytokine response compared to the isogenic wild type E. faecalis strain. In silico analysis predicted significant tertiary structure homology to the TIR domain of human TLR1 (TLR1-TIR). When transiently expressed in cultured eukaryotic cells, TcpF caused suppression of TLR2-dependent NF-κB activation suggesting for TcpF a role as a factor in E. faecalis that benefits colonization by modulating the host's immune responses.

  3. [Photoreactivation of Escherichia coli and Enterococcus faecalis in the secondary effluent disinfected by UV-TiO2].

    PubMed

    Wang, Xi-Feng; Gong, Xin; Hu, Xiao-Lian; Ren, Bo-Zhi

    2014-04-01

    Effects of photoreactivating light intensity (0-41 microW x cm(-2)) on photoreactivation of Escherichia coli (E. coli) and Enterococcus faecalis (E. faecalis) in the secondary effluent after UV and UV-TiO2 disinfection were investigated. The results indicated that the disinfection efficiency of UV-TiO2 was much higher than that of UV disinfection. The photoreactivation rate of E. coli was much higher in UV disinfection than that in UV-TiO2 disinfection. Under high light intensity in UV-TiO2 disinfection, high resurrection rate can be induced. However, a higher resurrection rate can be introduced even under low light intensity in the UV disinfection. Meanwhile, UV-TiO2 disinfection had a strong inhibition effect on E. faecalis photoreactivation, when the light intensity was lower than 21 microW x cm(-2), three was no resurrection occurred on E. faecalis after 72 h resurrection irradiation, only under a strong photoreactivating light intensity, the resurrection rate of E. faecalis was observed.

  4. An In Vitro Study on the Effects of Nisin on the Antibacterial Activities of 18 Antibiotics against Enterococcus faecalis

    PubMed Central

    Ling, Junqi; Ma, Jinglei; Huang, Lijia; Zhang, Luodan

    2014-01-01

    Enterococcus faecalis rank among the leading causes of nosocomial infections worldwide and possesses both intrinsic and acquired resistance to a variety of antibiotics. Development of new antibiotics is limited, and pathogens continually generate new antibiotic resistance. Many researchers aim to identify strategies to effectively kill this drug-resistant pathogen. Here, we evaluated the effect of the antimicrobial peptide nisin on the antibacterial activities of 18 antibiotics against E. faecalis. The MIC and MBC results showed that the antibacterial activities of 18 antibiotics against E. faecalis OG1RF, ATCC 29212, and strain E were significantly improved in the presence of 200 U/ml nisin. Statistically significant differences were observed between the results with and without 200 U/ml nisin at the same concentrations of penicillin or chloramphenicol (p<0.05). The checkerboard assay showed that the combination of nisin and penicillin or chloramphenicol had a synergetic effect against the three tested E. faecalis strains. The transmission electron microscope images showed that E. faecalis was not obviously destroyed by penicillin or chloramphenicol alone but was severely disrupted by either antibiotic in combination with nisin. Furthermore, assessing biofilms by a confocal laser scanning microscope showed that penicillin, ciprofloxacin, and chloramphenicol all showed stronger antibiofilm actions in combination with nisin than when these antibiotics were administered alone. Therefore, nisin can significantly improve the antibacterial and antibiofilm activities of many antibiotics, and certain antibiotics in combination with nisin have considerable potential for use as inhibitors of this drug-resistant pathogen. PMID:24586598

  5. The effect of temperature and contact time of sodium hypochlorite on human roots infected with Enterococcus faecalis and Candida albicans.

    PubMed

    Gulsahi, Kamran; Tirali, R Ebru; Cehreli, S Burcak; Karahan, Zeynep Ceren; Uzunoglu, Emel; Sabuncuoglu, Bizden

    2014-01-01

    The aim of this study was to evaluate the effectiveness of 2.5 % NaOCl at different temperature and time intervals on Enterococcus faecalis and Candida albicans-infected human roots. A total of 112 root cylinders prepared from extracted single-rooted humans were infected by E. faecalis (Group A, n = 56) or C. albicans (Group B, n = 56); 3 root cylinders served as negative controls. Both groups were further divided into 6 subgroups according to three contact times (30 s, 1 min, 5 min) with NaOCl at two different temperatures (25 or 37 °C). Microorganism growth was controlled at the 24th and 48th hours. Statistical analysis was performed using the Chi-square test. While NaOCl at 25 °C for 5 min was the most effective irrigation regimen to eliminate E. faecalis (p < 0.001), NaOCl at 37 °C for 5 min exhibited significantly superior antifungal properties (p < 0.05). At the same contact times, difference in the temperature of NaOCl did not affect the growth of either E. faecalis or C. albicans. As a result, the irrigation time of NaOCl was more effective than the temperature to eliminate E. faecalis, while pre-heating of NaOCl to 37 °C increased its effectiveness on C. albicans at 5 min contact time.

  6. The effect of sodium hypochlorite on Enterococcus faecalis when grown on dentine as a single- and multi-species biofilm.

    PubMed

    Yap, Benlee; Zilm, Peter S; Briggs, Nancy; Rogers, Anthony H; Cathro, Peter C

    2014-12-01

    Enterococcus faecalis is often involved in the aetiology of apical periodontitis after endodontic treatment. This project aimed to establish, on dentine in vitro, a multi-species biofilm containing E. faecalis, and to determine if the organism had an increased resistance to sodium hypochlorite compared with an axenic biofilm. Biofilms were established on dentine discs in flow cells with either E. faecalis alone (axenic) or together with Fusobacterium nucleatum and Streptococcus sanguinis. Following treatment with either 0.9% sodium hypochlorite or saline, the viability of E. faecalis was determined by serial plating and qualitative analysis was performed by scanning electron microscopy and confocal laser scanning microscopy. Viable counts indicated that 0.9% NaOCl is highly effective against E. faecalis grown alone and as part of a multi-species biofilm (P = 0.0005 and P = 0.001, respectively). No significant difference in its survival in the two biofilm types was found (P = 0.8276).

  7. The Polyamine N-Acetyltransferase-Like Enzyme PmvE Plays a Role in the Virulence of Enterococcus faecalis

    PubMed Central

    Martini, Cecilia; Michaux, Charlotte; Bugli, Francesca; Arcovito, Alessandro; Iavarone, Federica; Cacaci, Margherita; Sterbini, Francesco Paroni; Hartke, Axel; Sauvageot, Nicolas; Sanguinetti, Maurizio; Posteraro, Brunella

    2014-01-01

    We previously showed that the mutant strain of Enterococcus faecalis lacking the transcriptional regulator SlyA is more virulent than the parental strain. We hypothesized that this phenotype was due to overexpression of the second gene of the slyA operon, ef_3001, renamed pmvE (for polyamine metabolism and virulence of E. faecalis). PmvE shares strong homologies with N1-spermidine/spermine acetyltransferase enzymes involved in the metabolism of polyamines. In this study, we used an E. faecalis strain carrying the recombinant plasmid pMSP3535-pmvE (V19/p3535-pmvE), which allows the induction of pmvE by addition of nisin. Thereby, we showed that the overexpression of PmvE increased the virulence of E. faecalis in the Galleria mellonella infection model, as well as the persistence within peritoneal macrophages. We were also able to show a direct interaction between the His-tagged recombinant PmvE (rPmvE) protein and putrescine by the surface plasmon resonance (SPR) technique on a Biacore instrument. Moreover, biochemical assays showed that PmvE possesses an N-acetyltransferase activity toward polyamine substrates. Our results suggest that PmvE contributes to the virulence of E. faecalis, likely through its involvement in the polyamine metabolism. PMID:25385793

  8. Antibacterial and residual antimicrobial activities against Enterococcus faecalis biofilm: A comparison between EDTA, chlorhexidine, cetrimide, MTAD and QMix

    NASA Astrophysics Data System (ADS)

    Zhang, Rui; Chen, Min; Lu, Yan; Guo, Xiangjun; Qiao, Feng; Wu, Ligeng

    2015-08-01

    We compared the antibacterial and residual antimicrobial activities of five root canal irrigants (17% EDTA,2% chlorhexidine,0.2% cetrimide, MTAD, and QMix) in a model of Enterococcus faecalis biofilm formation. Sixty dentin blocks with 3-week E. faecalis biofilm were divided into six equal groups and flushed with irrigant for 2 min or left untreated. A blank control group was also established. Antibacterial activities of the irrigants were evaluated by counting colony forming units. To test residual antimicrobial activities, 280 dentin blocks were divided into seven equal groups and flushed with irrigant for 2 min or left untreated and then incubated with E. faecalis suspension for 48 h, or used as a blank. No bacteria were observed in the blank control group. The number of viable E. faecalis was significantly fewer in the irrigant-treated groups compared with the untreated control (P < 0.05). Among the five irrigants, QMix had the strongest antibacterial activity. Residual antimicrobial activities of CHX were significantly higher at 12 h, 24 h and 36 h compared to untreated control (P < 0.05). All five root canal irrigants were effective to some extent against E. faecalis, but QMix and CHX had the strongest, and CHX the longest (up to 36 h), antimicrobial activity.

  9. Biofilm formation on polystyrene under different temperatures by antibiotic resistant Enterococcus faecalis and Enterococcus faecium isolated from food.

    PubMed

    Marinho, A R; Martins, P D; Ditmer, E M; d'Azevedo, P A; Frazzon, J; Van Der Sand, S T; Frazzon, A P G

    2013-01-01

    The ability of antibiotic resistant E. faecalis and E. faecium isolated from food to form biofilm at different temperatures in the absence or presence of 0.75% glucose was evaluated. A synergistic effect on biofilm at 10 °C, 28 °C, 37 °C and 45 °C and glucose was observed for E. faecalis and E. faecium.

  10. Transcriptome Analysis of Enterococcus faecalis during Mammalian Infection Shows Cells Undergo Adaptation and Exist in a Stringent Response State

    PubMed Central

    Frank, Kristi L.; Colomer-Winter, Cristina; Grindle, Suzanne M.; Lemos, José A.; Schlievert, Patrick M.; Dunny, Gary M.

    2014-01-01

    As both a commensal and a major cause of healthcare-associated infections in humans, Enterococcus faecalis is a remarkably adaptable organism. We investigated how E. faecalis adapts in a mammalian host as a pathogen by characterizing changes in the transcriptome during infection in a rabbit model of subdermal abscess formation using transcriptional microarrays. The microarray experiments detected 222 and 291 differentially regulated genes in E. faecalis OG1RF at two and eight hours after subdermal chamber inoculation, respectively. The profile of significantly regulated genes at two hours post-inoculation included genes involved in stress response, metabolism, nutrient acquisition, and cell surface components, suggesting genome-wide adaptation to growth in an altered environment. At eight hours post-inoculation, 88% of the differentially expressed genes were down-regulated and matched a transcriptional profile consistent with a (p)ppGpp-mediated stringent response. Subsequent subdermal abscess infections with E. faecalis mutants lacking the (p)ppGpp synthetase/hydrolase RSH, the small synthetase RelQ, or both enzymes, suggest that intracellular (p)ppGpp levels, but not stringent response activation, influence persistence in the model. The ability of cells to synthesize (p)ppGpp was also found to be important for growth in human serum and whole blood. The data presented in this report provide the first genome-wide insights on E. faecalis in vivo gene expression and regulation measured by transcriptional profiling during infection in a mammalian host and show that (p)ppGpp levels affect viability of E. faecalis in multiple conditions relevant to mammalian infection. The subdermal abscess model can serve as a novel experimental system for studying the E. faecalis stringent response in the context of the mammalian immune system. PMID:25545155

  11. Horizontal transfer of antibiotic resistance from Enterococcus faecium of fermented meat origin to clinical isolates of E. faecium and Enterococcus faecalis.

    PubMed

    Jahan, Musarrat; Zhanel, George G; Sparling, Richard; Holley, Richard A

    2015-04-16

    Enterococcus species are part of the normal intestinal flora of a large number of mammals including humans and consequently, they can be used as indicators of faecal contamination in food and water for human consumption. Their presence in large numbers in foods may indicate a lapse in sanitation and their ability to serve as a genetic reservoir of transferable antibiotic resistance is of concern. In the present study, Enterococcus spp., isolated from commercially fermented meat and human clinical specimen were studied to determine genetic relationships. SmaI pulsed-field gel electrophoresis (PFGE) patterns exhibited genomic heterogeneity within and between both groups of isolates. However, in spite of this heterogeneity there were still substantial phenotypic similarities which suggested that food might be a potential vehicle for distribution of resistant bacteria among humans. In vitro conjugation experiments demonstrated transfer of the tetracycline resistant determinant, tet(M), from Enterococcus faecium S27 isolated from fermented sausage to clinical isolates of both E. faecium and Enterococcus faecalis. The streptomycin resistance of E. faecium S27 was also transferred to a clinical strain, E. faecalis 82916, which was confirmed by the presence of the streptomycin resistance gene, aadA, in the donor and transconjugant strains. Since the aadA gene is associated with a class 1 integron, results also suggested that resistance transfer might have occurred via an integron. It appears this is the first identification of a class 1 integron in E. faecium isolated from food. The importance of food enterococci as a reservoir of antibiotic resistance genes and the potential for their genetic transfer to human strains following consumption of uncooked or undercooked contaminated meat is underlined by this work.

  12. Native Microbial Colonization of Drosophila melanogaster and Its Use as a Model of Enterococcus faecalis Pathogenesis▿ †

    PubMed Central

    Cox, Christopher R.; Gilmore, Michael S.

    2007-01-01

    Enterococci are commensal organisms of the gastrointestinal (GI) tracts of a broad range of mammalian and insect hosts, but they are also leading causes of nosocomial infection. Little is known about the ecological role of enterococci in the GI tract consortia. To develop a tractable model for studying the roles of these organisms as commensals and pathogens, we characterized the Drosophila melanogaster microflora and examined the occurrence of enterococci in the gastrointestinal consortium of Drosophila. In a survey of laboratory-reared Drosophila and wild-captured flies, we found that Drosophila was naturally colonized by representatives of five bacterial phyla. Among these organisms were several species of enterococci, including Enterococcus faecalis, Enterococcus faecium, Enterococcus gallinaraum, and Enterococcus durans, as well as a previously detected but uncultured Enterococcus species. Drosophila could be cured of enterococcal carriage by antibiotic treatment and could be reassociated with laboratory strains. High-level colonization by a well-characterized strain expressing the enterococcal cytolysin was found to be detrimental to Drosophila compared to the effect of an isogenic, noncytolytic control. The anatomical distribution of enterococci in the Drosophila GI tract was determined by immunohistochemical staining of thin sections of naturally colonized and reassociated flies. PMID:17220307

  13. Effect of smear layer against disinfection protocols on Enterococcus faecalis-infected dentin.

    PubMed

    Wang, Zhejun; Shen, Ya; Haapasalo, Markus

    2013-11-01

    This study examined the effect of the smear layer on the antibacterial effect of different disinfecting solutions in infected dentinal tubules. Cells of Enterococcus faecalis were forced into dentinal tubules according to a previously established protocol. After a 3-week incubation period of infected dentin blocks, a uniform smear layer was produced. Forty infected dentin specimens were prepared and subjected to 3 and 10 minutes of exposure to disinfecting solutions including sterile water, 2% and 6% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), 17% EDTA, and QMiX (Dentsply Tulsa Dental, Tulsa, OK). The following combinations were also included: 2% NaOCl + 2% CHX, 2% NaOCl + QMiX, 6% NaOCl + QMiX, and 6% NaOCl + 17% EDTA + 2% CHX. Four other dentin specimens similarly infected but with no smear layer were subjected to 3 minutes of exposure to 2% CHX and 6% NaOCl for comparison. Confocal laser scanning microscopy and viability staining were used to analyze the proportions of dead and live bacteria inside the dentin. In the presence of a smear layer, 10 minutes of exposure to QMiX, 2% NaOCl + QMiX, 6% NaOCl + QMiX, and 6% NaOCl + 17% EDTA + 2% CHX resulted in significantly more dead bacteria than 3 minutes of exposure to these same disinfecting solutions (P < .05). No statistically significant difference between 3 and 10 minutes was found in other groups (P > .05); 6% NaOCl + QMiX and 6% NaOCl + 17% EDTA + 2% CHX showed the strongest antibacterial effect. In the absence of a smear layer, 2% CHX and 6% NaOCl killed significantly more bacteria than they did in the presence of a smear layer (P < .05). The smear layer reduces the effectiveness of disinfecting agents against E. faecalis in infected dentin. Solutions containing 6% NaOCl and/or QMiX showed the highest antibacterial activity. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  14. Relationship between the Level of Acquired Resistance to Gentamicin and Synergism with Amoxicillin in Enterococcus faecalis

    PubMed Central

    Aslangul, Elisabeth; Ruimy, Raymond; Chau, Françoise; Garry, Louis; Andremont, Antoine; Fantin, Bruno

    2005-01-01

    In enterococci, intrinsic low-level resistance to gentamicin does not abolish synergism with a cell wall-active antibiotic while high-level resistance due to acquired aminoglycoside-modifying enzymes does. To study the impact of intermediate levels of resistance to gentamicin (64 < MIC < 500 μg/ml), we selected in vitro three consecutive generations of mutants of Enterococcus faecalis JH2-2 with MICs of gentamicin at 128 μg/ml for G1-1477, 256 μg/ml for G2-1573, and 512 μg/ml for G3-1688. E. faecalis 102, which is highly resistant to gentamicin by enzymatic inactivation was used as control. In in vitro killing curves experiments, gentamicin concentrations allowing bactericidal activity and synergism in combination with amoxicillin increased from 4 μg/ml (1/16th the MIC), 16 μg/ml (one-eighth the MIC), 64 μg/ml (one-quarter the MIC), and 256 μg/ml (one-half the MIC) for strains JH2-2, G1-1477, G2-1573 and G3-1688, respectively. As expected, no bactericidal effect of the combination or synergism could be obtained with strain 102. In rabbits with aortic endocarditis caused by strain G1-1477 or G2-1573, combination therapy with amoxicillin and gentamicin was significantly more active than amoxicillin alone (P < 0.05) but not in those infected with the strains G3-1688 and 102. Thus, intermediate levels of resistance to gentamicin was not associated with a loss of a beneficial effect of the gentamicin-amoxicillin combination in vivo even though higher concentrations of gentamicin were necessary to achieve in vitro synergism. Therefore, the use of an MIC of 500 μg/ml as a clinical cutoff limit to predict in vivo benefit of the combination remains a simple and effective tool. PMID:16189091

  15. Exogenous Fatty Acids Protect Enterococcus faecalis from Daptomycin-Induced Membrane Stress Independently of the Response Regulator LiaR

    PubMed Central

    Harp, John R.; Saito, Holly E.; Bourdon, Allen K.; Reyes, Jinnethe; Arias, Cesar A.

    2016-01-01

    ABSTRACT Enterococcus faecalis is a commensal bacterium of the gastrointestinal tract that can cause nosocomial infections in immunocompromised humans. The hallmarks of this organism are its ability to survive in a variety of stressful habitats and, in particular, its ability to withstand membrane damage. One strategy used by E. faecalis to protect itself from membrane-damaging agents, including the antibiotic daptomycin, involves incorporation of exogenous fatty acids from bile or serum into the cell membrane. Additionally, the response regulator LiaR (a member of the LiaFSR [lipid II-interacting antibiotic response regulator and sensor] system associated with cell envelope stress responses) is required for the basal level of resistance E. faecalis has to daptomycin-induced membrane damage. This study aimed to determine if membrane fatty acid changes could provide protection against membrane stressors in a LiaR-deficient strain of E. faecalis. We noted that despite the loss of LiaR, the organism readily incorporated exogenous fatty acids into its membrane, and indeed growth in the presence of exogenous fatty acids increased the survival of LiaR-deficient cells when challenged with a variety of membrane stressors, including daptomycin. Combined, our results suggest that E. faecalis can utilize both LiaR-dependent and -independent mechanisms to protect itself from membrane damage. IMPORTANCE Enterococcus faecalis is responsible for a significant number of nosocomial infections. Worse, many of the antibiotics used to treat E. faecalis infection are no longer effective, as this organism has developed resistance to them. The drug daptomycin has been successfully used to treat some of these resistant strains; however, daptomycin-resistant isolates have been identified in hospitals. Many daptomycin-resistant isolates are found to harbor mutations in the genetic locus liaFSR, which is involved in membrane stress responses. Another mechanism shown to increase tolerance to

  16. Antimicrobial efficacy of different concentration of sodium hypochlorite on the biofilm of Enterococcus faecalis at different stages of development

    PubMed Central

    Frough-Reyhani, Mohammad; Soroush-Barhaghi, Mohammadhosien; Amini, Mahsa; Gholizadeh, Yousefreza

    2016-01-01

    Background Persistent infection of the root canal due to the presence of resistance bacterial species, such as Enterococcus faecalis, has always been one of the most important reasons for endodontic treatment failure. This study investigated the antimicrobial efficacy of 1%, 2.5 % and 5% sodium hypochlorite in eliminating E. faecalis biofilms at different stages of development. Material and Methods In this study 4-, 6- and 10-week-old E. faecalis biofilms were subjected to one of the following approaches: phosphate-buffered saline solution (PBS) or 1%, 2.5% and 5% NaOCl. Dentin chip suspensions were used for colony forming unit (CFU) counting to estimate remaining E. faecalis counts. Statistical comparison of the means was carried out with Kruskal-Wallis test, and pair-wise comparisons were made by Mann-Whitney U test, at a significance level of P<0.05. Results The results showed that 2.5% and 5% NaOCl completely eliminated E. faecalis biofilms in three stages of biofilm development, whereas 1% NaOCl resulted in 85.73%, 81.88% and 78.62% decreases in bacterial counts in 4-, 6- and 10-week-old biofilms, respectively, which was significantly more than those with PBS (p<0.05). Conclusions The bacteria in mature and old biofilms were more resistant to 1% NaOCl than were the bacteria in young biofilms. Overall survival rate and residual bacteria increased with biofilm aging. Key words:Antibacterial, biofilm, E. faecalis, sodium hypochlorite. PMID:27957257

  17. Effects of lysed Enterococcus faecalis FK-23 on experimental allergic rhinitis in a murine model

    PubMed Central

    Zhu, Luping; Shimada, Takashi; Chen, Ruoxi; Lu, Meiping; Zhang, Qingzhao; Lu, Wenmin; Yin, Min; Enomoto, Tadao; Cheng, Lei

    2012-01-01

    In the current study, we sought to investigate whether lysed Enterococcus faecalis FK-23 (LFK), a heat-killed probiotic preparation, attenuated eosinophil influx into the upper airway and had immunomodulatory activity in a murine allergic rhinitis model. Eighteen BALB/c mice were divided into three groups; the ovalbumin (OVA)-sensitized/challenged group, which received saline orally for 6 weeks (OVA group), the OVA-sensitized/challenged group, which received LFK orally for 6 weeks (LFK-fed group), and the non-sensitized group, which received saline for 6 weeks (saline control group). Nasal rubbing and sneezing were monitored during the study. After the final challenge, interleukin (IL)-4, interferon (IFN)-γ, and OVA-specific IgE levels in the sera and splenocyte culture supernatants were determined, eosinophilic infiltrate into the upper airway was quantified, and splenic CD4+CD25+ regulatory T cells (Tregs) were examined by flow cytometry. We found that nasal rubbing was significantly reduced in LFK-fed mice compared to the OVA group on d 27 and 35, and sneezing was significantly inhibited by LFK administration for 35 d. LFK-fed mice had significantly less eosinophil influx into the nasal mucosa than the OVA group. There were no significant differences between the LFK-fed group and OVA group in the serum and splenocyte culture supernatant levels of IL-4, IFN-γ, and OVA-specific IgE. Interestingly, the LFK-fed mice had a significantly greater percentage of splenic CD4+CD25+ Tregs than OVA group. Our results indicate that oral administration of LFK may alleviate nasal symptoms, reduce nasal eosinophilia, and increase the percentage of CD4+CD25+ Tregs in experimental allergic rhinitis. PMID:23554753

  18. Enterococcus faecalis Inhibits Superantigen Toxic Shock Syndrome Toxin-1-Induced Interleukin-8 from Human Vaginal Epithelial Cells through Tetramic Acids

    PubMed Central

    Brosnahan, Amanda J.; Merriman, Joseph A.; Salgado-Pabón, Wilmara; Ford, Bradley; Schlievert, Patrick M.

    2013-01-01

    The vaginal mucosa can be colonized by many bacteria including commensal organisms and potential pathogens, such as Staphylococcus aureus. Some strains of S. aureus produce the superantigen toxic shock syndrome toxin-1, which can penetrate the vaginal epithelium to cause toxic shock syndrome. We have observed that a female was mono-colonized with Enterococcus faecalis vaginally as tested in aerobic culture, even upon repeated culture for six months, suggesting this organism was negatively influencing colonization by other bacteria. In recent studies, we demonstrated an “outside-in” mechanism of cytokine signaling and consequent inflammation that facilitates the ability of potential pathogens to initiate infection from mucosal surfaces. Thus, we hypothesized that this strain of E. faecalis may make anti-inflammatory factors which block disease progression of more pathogenic organisms. E. faecalis MN1 inhibited interleukin-8 production from human vaginal epithelial cells in response to the vaginal pathogens Candida albicans, Gardnerella vaginalis, and Neisseria gonorrhoeae, as well as to toxic shock syndrome toxin-1. We further demonstrated that this organism secretes two tetramic acid compounds which appear responsible for inhibition of interleukin-8 production, as well as inhibition of T cell proliferation due to toxic shock syndrome toxin-1. Microbicides that include anti-inflammatory molecules, such as these tetramic acid compounds naturally produced by E. faecalis MN1, may be useful in prevention of diseases that develop from vaginal infections. PMID:23613823

  19. IS256 abolishes gelatinase activity and biofilm formation in a mutant of the nosocomial pathogen Enterococcus faecalis V583.

    PubMed

    Perez, Marta; Calles-Enríquez, Marina; del Rio, Beatriz; Ladero, Victor; Martín, María Cruz; Fernández, María; Alvarez, Miguel A

    2015-07-01

    Enterococcus faecalis is one of the most controversial species of lactic acid bacteria. Some strains are used as probiotics, while others are associated with severe and life-threatening nosocomial infections. Their pathogenicity depends on the acquisition of multidrug resistance and virulence factors. Gelatinase, which is required in the first steps of biofilm formation, is an important virulence determinant involved in E. faecalis pathogenesis, including endocarditis and peritonitis. The gene that codes for gelatinase (gelE) is controlled by the Fsr quorum-sensing system, whose encoding genes (fsrA, fsrB, fsrC, and fsrD) are located immediately upstream of gelE. The integration of a DNA fragment into the fsr locus of a derived mutant of E. faecalis V583 suppressed the gelatinase activity and prevented biofilm formation. Sequence analysis indicated the presence of IS256 integrated into the fsrC gene at nucleotide position 321. Interestingly, IS256 is also associated with biofilm formation in Staphylococcus epidermidis and Staphylococcus aureus. This is the first description of an insertion sequence that prevents biofilm formation in E. faecalis.

  20. Immunostimulatory Effects Triggered by Enterococcus faecalis CECT7121 Probiotic Strain Involve Activation of Dendritic Cells and Interferon-Gamma Production.

    PubMed

    Molina, Matías Alejandro; Díaz, Ailén Magalí; Hesse, Christina; Ginter, Wiebke; Gentilini, María Virginia; Nuñez, Guillermo Gabriel; Canellada, Andrea Mercedes; Sparwasser, Tim; Berod, Luciana; Castro, Marisa Silvia; Manghi, Marcela Alejandra

    2015-01-01

    Probiotics can modulate the immune system, conferring beneficial effects on the host. Understanding how these microorganisms contribute to improve the health status is still a challenge. Previously, we have demonstrated that Enterococcus faecalis CECT7121 implants itself and persists in the murine gastrointestinal tract, and enhances and skews the profile of cytokines towards the Th1 phenotype in several biological models. Given the importance of dendritic cells (DCs) in the orchestration of immunity, the aim of this work was to elucidate the influence of E. faecalis CECT7121 on DCs and the outcome of the immune responses. In this work we show that E. faecalis CECT7121 induces a strong dose-dependent activation of DCs and secretion of high levels of IL-12, IL-6, TNFα, and IL-10. This stimulation is dependent on TLR signaling, and skews the activation of T cells towards the production of IFNγ. The influence of this activation in the establishment of Th responses in vivo shows the accumulation of specific IFNγ-producing cells. Our findings indicate that the activation exerted by E. faecalis CECT7121 on DCs and its consequence on the cellular adaptive immune response may have broad therapeutic implications in immunomodulation.

  1. Immunostimulatory Effects Triggered by Enterococcus faecalis CECT7121 Probiotic Strain Involve Activation of Dendritic Cells and Interferon-Gamma Production

    PubMed Central

    Molina, Matías Alejandro; Díaz, Ailén Magalí; Hesse, Christina; Ginter, Wiebke; Gentilini, María Virginia; Nuñez, Guillermo Gabriel; Canellada, Andrea Mercedes; Sparwasser, Tim; Berod, Luciana; Castro, Marisa Silvia; Manghi, Marcela Alejandra

    2015-01-01

    Probiotics can modulate the immune system, conferring beneficial effects on the host. Understanding how these microorganisms contribute to improve the health status is still a challenge. Previously, we have demonstrated that Enterococcus faecalis CECT7121 implants itself and persists in the murine gastrointestinal tract, and enhances and skews the profile of cytokines towards the Th1 phenotype in several biological models. Given the importance of dendritic cells (DCs) in the orchestration of immunity, the aim of this work was to elucidate the influence of E. faecalis CECT7121 on DCs and the outcome of the immune responses. In this work we show that E. faecalis CECT7121 induces a strong dose-dependent activation of DCs and secretion of high levels of IL-12, IL-6, TNFα, and IL-10. This stimulation is dependent on TLR signaling, and skews the activation of T cells towards the production of IFNγ. The influence of this activation in the establishment of Th responses in vivo shows the accumulation of specific IFNγ-producing cells. Our findings indicate that the activation exerted by E. faecalis CECT7121 on DCs and its consequence on the cellular adaptive immune response may have broad therapeutic implications in immunomodulation. PMID:25978357

  2. Enterococcus faecalis inhibits superantigen toxic shock syndrome toxin-1-induced interleukin-8 from human vaginal epithelial cells through tetramic acids.

    PubMed

    Brosnahan, Amanda J; Merriman, Joseph A; Salgado-Pabón, Wilmara; Ford, Bradley; Schlievert, Patrick M

    2013-01-01

    The vaginal mucosa can be colonized by many bacteria including commensal organisms and potential pathogens, such as Staphylococcus aureus. Some strains of S. aureus produce the superantigen toxic shock syndrome toxin-1, which can penetrate the vaginal epithelium to cause toxic shock syndrome. We have observed that a female was mono-colonized with Enterococcus faecalis vaginally as tested in aerobic culture, even upon repeated culture for six months, suggesting this organism was negatively influencing colonization by other bacteria. In recent studies, we demonstrated an "outside-in" mechanism of cytokine signaling and consequent inflammation that facilitates the ability of potential pathogens to initiate infection from mucosal surfaces. Thus, we hypothesized that this strain of E. faecalis may make anti-inflammatory factors which block disease progression of more pathogenic organisms. E. faecalis MN1 inhibited interleukin-8 production from human vaginal epithelial cells in response to the vaginal pathogens Candida albicans, Gardnerella vaginalis, and Neisseria gonorrhoeae, as well as to toxic shock syndrome toxin-1. We further demonstrated that this organism secretes two tetramic acid compounds which appear responsible for inhibition of interleukin-8 production, as well as inhibition of T cell proliferation due to toxic shock syndrome toxin-1. Microbicides that include anti-inflammatory molecules, such as these tetramic acid compounds naturally produced by E. faecalis MN1, may be useful in prevention of diseases that develop from vaginal infections.

  3. Tyramine biosynthesis is transcriptionally induced at low pH and improves the fitness of Enterococcus faecalis in acidic environments.

    PubMed

    Perez, Marta; Calles-Enríquez, Marina; Nes, Ingolf; Martin, Maria Cruz; Fernandez, Maria; Ladero, Victor; Alvarez, Miguel A

    2015-04-01

    Enterococcus faecalis is a commensal bacterium of the human gut that requires the ability to pass through the stomach and therefore cope with low pH. E. faecalis has also been identified as one of the major tyramine producers in fermented food products, where they also encounter acidic environments. In the present work, we have constructed a non-tyramine-producing mutant to study the role of the tyramine biosynthetic pathway, which converts tyrosine to tyramine via amino acid decarboxylation. Wild-type strain showed higher survival in a system that mimics gastrointestinal stress, indicating that the tyramine biosynthetic pathway has a role in acid resistance. Transcriptional analyses of the E. faecalis V583 tyrosine decarboxylase cluster showed that an acidic pH, together with substrate availability, induces its expression and therefore the production of tyramine. The protective role of the tyramine pathway under acidic conditions appears to be exerted through the maintenance of the cytosolic pH. Tyramine production should be considered important in the adaptability of E. faecalis to acidic environments, such as fermented dairy foods, and to survive passage through the human gastrointestinal tract.

  4. Sunlight mediated inactivation mechanisms of Enterococcus faecalis and Escherichia coli in clear water versus waste stabilization pond water.

    PubMed

    Kadir, Khalid; Nelson, Kara L

    2014-03-01

    Escherichia coli and enterococci have been previously reported to differ in the mechanisms and conditions that affect their sunlight-mediated inactivation in waste stabilization ponds. This study was undertaken to further characterize these mechanisms, using simulated sunlight and single strains of laboratory-grown E. coli and Enterococcus faecalis, with a focus on characterizing the contribution of exogenous reactive oxygen species to the inactivation process. We found that direct damage by UVB light (280-320 nm) was not a significant inactivation mechanism for either organism. E. coli inactivation was strongly dependent on dissolved oxygen concentrations and the presence of UVB wavelengths but E. coli were not susceptible to inactivation by exogenous sensitizers present in waste stabilization pond water. In contrast, E. faecalis inactivation in pond water occurred primarily through exogenous mechanisms, with strong evidence that singlet oxygen is an important transient reactive species. The exogenous mechanism could utilize wavelengths into the visible spectrum and sensitizers were mainly colloidal, distributed between 0.2 and ∼1 μm in size. Singlet oxygen is likely an important endogenous species in both E. faecalis and E. coli inactivation due to sunlight. Although the two organisms had similar inactivation rates in buffered, clear water, the inactivation rate of E. faecalis was 7 times greater than that of E. coli in air-saturated pond water at circumneutral pH due to its susceptibility to exogenous sensitizers and longer wavelengths.

  5. The Two Functional Enoyl-Acyl Carrier Protein Reductases of Enterococcus faecalis Do Not Mediate Triclosan Resistance

    PubMed Central

    Zhu, Lei; Bi, Hongkai; Ma, Jincheng; Hu, Zhe; Zhang, Wenbin; Cronan, John E.; Wang, Haihong

    2013-01-01

    ABSTRACT Enoyl-acyl carrier protein (enoyl-ACP) reductase catalyzes the last step of the elongation cycle in the synthesis of bacterial fatty acids. The Enterococcus faecalis genome contains two genes annotated as enoyl-ACP reductases, a FabI-type enoyl-ACP reductase and a FabK-type enoyl-ACP reductase. We report that expression of either of the two proteins restores growth of an Escherichia coli fabI temperature-sensitive mutant strain under nonpermissive conditions. In vitro assays demonstrated that both proteins support fatty acid synthesis and are active with substrates of all fatty acid chain lengths. Although expression of E. faecalis fabK confers to E. coli high levels of resistance to the antimicrobial triclosan, deletion of fabK from the E. faecalis genome showed that FabK does not play a detectable role in the inherent triclosan resistance of E. faecalis. Indeed, FabK seems to play only a minor role in modulating fatty acid composition. Strains carrying a deletion of fabK grow normally without fatty acid supplementation, whereas fabI deletion mutants make only traces of fatty acids and are unsaturated fatty acid auxotrophs. PMID:24085780

  6. Antimicrobial Effect of Lippia sidoides and Thymol on Enterococcus faecalis Biofilm of the Bacterium Isolated from Root Canals

    PubMed Central

    Veras, H. N. H.; Rodrigues, F. F. G.; Botelho, M. A.; Menezes, I. R. A.; Coutinho, H. D. M.; da Costa, J. G. M.

    2014-01-01

    The species Lippia sidoides Cham. (Verbenaceae) is utilized in popular medicine as a local antiseptic on the skin and mucosal tissues. Enterococcus faecalis is the bacterium isolated from root canals of teeth with persistent periapical lesions and has the ability to form biofilm, where it is responsible for the failure of endodontic treatments. Essential oil of L. sidoides (EOLS) and its major component, thymol, were evaluated for reducing the CFU in biofilms of E. faecalis in vitro. The essential oil was obtained by hydrodistillation and examined with respect to the chemical composition, by gas chromatography-mass spectrometry (GC-MS). The GC-MS analysis has led to the identification of thymol (84.9%) and p-cymene (5.33%). EOLS and thymol reduced CFU in biofilms of E. faecalis in vitro (time of maturation, 72 h), with an exposure time of 30 and 60 min at concentrations of 2.5 and 10%. There was no statistical difference in effect between EOLS and thymol, demonstrating that this phenolic monoterpene was the possible compound responsible for the antimicrobial activity of EOLS. This study provides a basis for the possible utilization of EOLS as an adjuvant in the treatment of root canals that show colonization by E. faecalis. PMID:24683344

  7. Spread of an Enterococcus faecalis sequence type 6 (CC2) clone in patients undergoing selective decontamination of the digestive tract.

    PubMed

    Muruzábal-Lecumberri, Izaskun; Girbau, Cecilia; Canut, Andrés; Alonso, Rodrigo; Fernández-Astorga, Aurora

    2015-03-01

    Enterococcus faecalis (E. faecalis) is a common cause of nosocomial infection in immunocompromised patients. The presence and dissemination of high-risk clonal complexes, such as CC2, is an ongoing problem in hospitals. The aim of this work was to characterize 24 E. faecalis isolates from ICU patients undergoing selective decontamination of the digestive tract (SDD) by phenotypical (antimicrobial susceptibility) and genotypical (presence of virulence genes, RAPD-PCR and MLST) methods. Our results showed high prevalence of the ST6 E. faecalis clone (91.6%), especially adapted to the hospital environment, with a multidrug resistance pattern and a multitude of putative virulence genes. In addition, ST179 (4.2%) and ST191 (4.2%) were detected. By RAPD-PCR analysis, the 22 isolates identified as ST6 showed six different DNA patterns, while the two remaining isolates, ST179 and ST191, showed two additional profiles. CC2 is a known clonal complex with high adaptability to hospital environment and worldwide distribution. The high prevalence of the ST6 clone in the studied population could be related to the presence of gentamicin in the SDD mixture since most strains were gentamicin resistant. Consequently, strict surveillance should be applied for rapid detection and control of this clone to prevent future spread outside the ICU.

  8. High rates of multidrug resistance in Enterococcus faecalis and E. faecium isolated from inpatients and outpatients in Taiwan.

    PubMed

    Wang, Jann-Tay; Chang, Shan-Chwen; Wang, Hui-Yin; Chen, Pei-Chen; Shiau, Yih-Ru; Lauderdale, Tsai-Ling

    2013-04-01

    Longitudinal national data on resistance in Enterococcus faecalis and E. faecium from different sources in Taiwan are rare. The present study analyzed data from the Taiwan Surveillance of Antimicrobial Resistance program to address this issue. Between 2002 and 2010, a total of 1696 E. faecalis and 452 E. faecium isolates were studied. Although these 2 species together comprised similar percentages of all enterococci in each study year (94.1-97.2%, P = 0.19), the proportion of E. faecium increased from 12.4% in 2002 to 27.3% in 2010 (P < 0.001). The most noteworthy change in susceptibilities of these 2 species was vancomycin resistance in E. faecium (VREfm), which increased from 0.3% in 2004 to 24.9% in 2010 (P < 0.001). VREfm prevalence differed significantly between geographic regions, patient age groups, and locations. Multidrug resistance was very common in both species even in isolates from outpatients (82.7% for E. faecalis and 98.1% for E. faecium), at rates similar to those from intensive care unit (ICU) and non-ICU patients (80.5-80.9% in E. faecalis and 97.2-98.6% in E. faecium). Nonsusceptibility to linezolid was <0.5% in both species. All tested isolates were susceptible to daptomycin. Continuous surveillance of VRE prevalence and survey of community reservoirs of multidrug-resistant enterococci are warranted. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Qualitative comparison of sonic or laser energisation of 4% sodium hypochlorite on an Enterococcus faecalis biofilm grown in vitro.

    PubMed

    Seet, Aaron N; Zilm, Peter S; Gully, Neville J; Cathro, Peter R

    2012-12-01

    The effectiveness of sonic activation, laser activation and syringe irrigation of 4% sodium hypochlorite in removing an Enterococcus faecalis biofilm was compared. Biofilms were grown in extracted human single rooted teeth using a flow cell apparatus. After 4 weeks' growth, teeth were subjected to each treatment using 4% sodium hypochlorite and radicular dentinal surfaces of the root canals were analysed by scanning electron microscopy. Results showed that sonic activation and syringe irrigation with sodium hypochlorite showed reduced numbers of bacterial cells on the radicular dentine but were not effective in eliminating E. faecalis in the dentinal tubules. Laser activation of sodium hypochlorite resulted in clean dentine walls and undetectable levels of bacteria within dentinal tubules. Qualitatively, sonic or laser activation of 4% NaOCl resulted in greater bacterial reduction compared with syringe irrigation, with laser activation producing the greatest overall reduction. © 2012 The Authors. Australian Endodontic Journal © 2012 Australian Society of Endodontology.

  10. Adhesion of Enterococcus faecalis 1131 grown under subinhibitory concentrations of ampicillin and vancomycin to a hydrophilic and a hydrophobic substratum.

    PubMed

    Gallardo-Moreno, A M; van der Mei, H C; Busscher, H J; González-Martín, M L; Bruque, J M; Pérez-Giraldo, C

    2001-09-11

    The effect of two subinhibitory antibiotic concentrations of ampicillin and vancomycin during growth on the adhesion of Enterococcus faecalis 1131 to glass and silicone rubber was studied in a parallel plate flow chamber. Initial deposition rates and numbers of adhering bacteria after 4 h were higher on hydrophilic glass than on hydrophobic silicone rubber, regardless of growth conditions. The presence of 1/4 minimal inhibitory concentration (MIC) of ampicillin during growth reduced enterococcal adhesion to both substrata, but growth in the presence of 1/4 MIC vancomycin did not affect the adhesion of E. faecalis. Moreover, enterococcal adhesion increased after growth in the presence of 1/8 MIC vancomycin. The increased adhesion after growth in the presence of subinhibitory concentrations of vancomycin may have strong implications for patients living with implanted biomaterials, as they may suffer adverse effects from use of this antibiotic, especially since bacteria once adhered are less sensitive to antibiotics.

  11. Characterization of a bacteriocin produced by Enterococcus faecalis N1-33 and its application as a food preservative.

    PubMed

    Hata, Tomomi; Alemu, Melaku; Kobayashi, Miho; Suzuki, Chise; Nitisinprasert, Sunee; Ohmomo, Sadahiro

    2009-03-01

    A bacteriocin-producing strain, N1-33, isolated from fermented bamboo shoot was identified as Enterococcus faecalis. The pH-adjusted culture supernatant of this strain consisted of several peptides with bacteriocin activity, and the supernatant inhibited the growth of pathogenic bacteria such as Listeria monocytogenes. The major peptide with bacteriocin activity was purified, and the first 39 amino acid residues of the bacteriocin were found to be identical to enterocin MR10A produced by E. faecalis MRR10-3. Addition of the pH-adjusted and concentrated culture supernatant of strain N1-33 caused a marked reduction in the growth of Bacillus cereus in custard cream and L. monocytogenes in pickled cucumber. These results suggest the potential use of the bacteriocin produced by strain N1-33 in food biopreservation.

  12. Ex situ study of Enterococcus faecalis survival in the recreational waters of the southern coast of the Caspian Sea.

    PubMed

    Irankhah, Sahar; Soudi, Mohammad Reza; Gharavi, Sara

    2016-04-01

    The US Environmental Protection Agency has suggested faecal enterococci as the primary bacterial indicators. Of more importance is their direct correlation with swimmer-associated gastroenteritis in recreation water quality monitoring. In contrast to other seawater bodies with 3.5% salinity, the recreational waters in the southern coast of the Caspian Sea possess its own salinity (about 1% w/v) and thus require further investigations to determine the capacity of Enterococcus faecalis as the sole primary microbial index in this unique aquatic environment. The survey of the presence and survival of E. faecalis as a microbial index in the recreational waters of the southern Caspian Sea was carried out using a microcosm as an experimental model. The concentration of E. faecalis cells in samples of seawater were estimated by a standard membrane filtration method using m-Enterococcus agar as the selective culture medium. As the current standard culture-based methods are not reliable enough for the detection of non-growing, damaged and under-tension bacteria, PCR was used to identify the possible VBNC form of the bacterium after disappearance of the culturable cells. A continuous decline in the number of culturable E. faecalis cells resulted in apparent elimination of the bacteria from seawater in a defined period. Detection of intact DNA was possible in the following 60 days. The salinity of about 1% and the self-purification properties of the Caspian Sea make the conditions feasible for the use of this microorganism as a measure of water quality throughout the region. The results confirmed the presence of damaged bacterial cells, namely VBNC forms, indicating the necessity of examining of the sea water samples by using molecular approaches or repair procedures.

  13. Ex situ study of Enterococcus faecalis survival in the recreational waters of the southern coast of the Caspian Sea

    PubMed Central

    Irankhah, Sahar; Soudi, Mohammad Reza; Gharavi, Sara

    2016-01-01

    Background and Objectives: The US Environmental Protection Agency has suggested faecal enterococci as the primary bacterial indicators. Of more importance is their direct correlation with swimmer-associated gastroenteritis in recreation water quality monitoring. In contrast to other seawater bodies with 3.5% salinity, the recreational waters in the southern coast of the Caspian Sea possess its own salinity (about 1% w/v) and thus require further investigations to determine the capacity of Enterococcus faecalis as the sole primary microbial index in this unique aquatic environment. Materials and Methods: The survey of the presence and survival of E. faecalis as a microbial index in the recreational waters of the southern Caspian Sea was carried out using a microcosm as an experimental model. The concentration of E. faecalis cells in samples of seawater were estimated by a standard membrane filtration method using m-Enterococcus agar as the selective culture medium. As the current standard culture-based methods are not reliable enough for the detection of non-growing, damaged and under-tension bacteria, PCR was used to identify the possible VBNC form of the bacterium after disappearance of the culturable cells. Results and Conclusion: A continuous decline in the number of culturable E. faecalis cells resulted in apparent elimination of the bacteria from seawater in a defined period. Detection of intact DNA was possible in the following 60 days. The salinity of about 1% and the self-purification properties of the Caspian Sea make the conditions feasible for the use of this microorganism as a measure of water quality throughout the region. The results confirmed the presence of damaged bacterial cells, namely VBNC forms, indicating the necessity of examining of the sea water samples by using molecular approaches or repair procedures. PMID:27307975

  14. Escherichia coli and Enterococcus faecalis are able to incorporate and enhance a pre-formed Gardnerella vaginalis biofilm.

    PubMed

    Castro, Joana; Machado, Daniela; Cerca, Nuno

    2016-04-01

    Gardnerella vaginalis is the most frequent microorganism found in bacterial vaginosis (BV), while Escherichia coli and Enterococcus faecalis are amongst the most frequent pathogens found in urinary tract infections (UTIs). This study aimed to evaluate possible interactions between UTIs pathogens and G. vaginalis using an in vitro dual-species biofilm model. Our results showed that dual-species biofilms reached significantly higher bacterial concentration than monospecies biofilms. Moreover, visualization of dual-populations species in the biofilms, using the epifluorescence microscopy, revealed that all of the urogenital pathogens coexisted with G. vaginalis. In conclusion, our work demonstrates that uropathogens can incorporate into mature BV biofilms.

  15. RNA of Enterococcus faecalis Strain EC-12 Is a Major Component Inducing Interleukin-12 Production from Human Monocytic Cells

    PubMed Central

    Nishibayashi, Ryoichiro; Inoue, Ryo; Harada, Yuri; Watanabe, Takumi; Makioka, Yuko; Ushida, Kazunari

    2015-01-01

    Interleukin-12 (IL-12) is an important cytokine for the immunomodulatory effects of lactic acid bacteria (LAB). Using murine immune cells, we previously reported that the RNA of Enterococcus faecalis EC-12, a LAB strain exerting probiotic-like beneficial effects, is the major IL-12-inducing immunogenic component. However, it was recently revealed that bacterial RNA can be a ligand for Toll-like receptor (TLR) 13, which is only expressed in mice. Because TLR13 is not expressed in humans, the immuno-stimulatory and -modulatory effects of LAB RNA in human cells should be augmented excluding TLR13 contribution. In experiment 1 of this study, the role of LAB RNA in IL-12 induction in human immune cells was studied using three LAB strains, E.faecalis EC-12, Lactobacillus gasseri JCM5344, and Bifidobacterium breve JCM1192. RNase A treatment of heat-killed LAB significantly decreased the IL-12 production of human peripheral blood mononuclear cells on stimulation, while RNase III treatment revealed virtually no effects. Further, IL-12 production against heat-killed E. faecalis EC-12 was abolished by depleting monocytes. These results demonstrated that single stranded RNA (ssRNA) of LAB is a strong inducer of IL-12 production from human monocytes. In experiment 2, major receptor for ssRNA of E. faecalis EC-12 was identified using THP-1 cells, a human monocytic cell line. The type of RNA molecules of E. faecalis EC-12 responsible for IL-12 induction was also identified. IL-12 production induced by the total RNA of E. faecalis EC-12 was significantly reduced by the treatment of siRNA for TLR8 but not for TLR7. Furthermore, both 23S and 16S rRNA, but not mRNA, of E. faecalis EC-12 markedly induced IL-12 production from THP-1 cells. These results suggested that the recognition of ssRNA of E. faecalis EC-12 was mediated by TLR8 and that rRNA was the RNA molecule that exhibited IL-12-inducing ability in human cells. PMID:26083838

  16. Enterococcus faecalis Uses a Phosphotransferase System Permease and a Host Colonization-Related ABC Transporter for Maltodextrin Uptake.

    PubMed

    Sauvageot, Nicolas; Mokhtari, Abdelhamid; Joyet, Philippe; Budin-Verneuil, Aurélie; Blancato, Víctor S; Repizo, Guillermo D; Henry, Céline; Pikis, Andreas; Thompson, John; Magni, Christian; Hartke, Axel; Deutscher, Josef

    2017-05-01

    Maltodextrin is a mixture of maltooligosaccharides, which are produced by the degradation of starch or glycogen. They are mostly composed of α-1,4- and some α-1,6-linked glucose residues. Genes presumed to code for the Enterococcus faecalis maltodextrin transporter were induced during enterococcal infection. We therefore carried out a detailed study of maltodextrin transport in this organism. Depending on their length (3 to 7 glucose residues), E. faecalis takes up maltodextrins either via MalT, a maltose-specific permease of the phosphoenolpyruvate (PEP):carbohydrate phosphotransferase system (PTS), or the ATP binding cassette (ABC) transporter MdxEFG-MsmX. Maltotriose, the smallest maltodextrin, is primarily transported by the PTS permease. A malT mutant therefore exhibits significantly reduced growth on maltose and maltotriose. The residual uptake of the trisaccharide is catalyzed by the ABC transporter, because a malT mdxF double mutant no longer grows on maltotriose. The trisaccharide arrives as maltotriose-6″-P in the cell. MapP, which dephosphorylates maltose-6'-P, also releases Pi from maltotriose-6″-P. Maltotetraose and longer maltodextrins are mainly (or exclusively) taken up via the ABC transporter, because inactivation of the membrane protein MdxF prevents growth on maltotetraose and longer maltodextrins up to at least maltoheptaose. E. faecalis also utilizes panose and isopanose, and we show for the first time, to our knowledge, that in contrast to maltotriose, its two isomers are primarily transported via the ABC transporter. We confirm that maltodextrin utilization via MdxEFG-MsmX affects the colonization capacity of E. faecalis, because inactivation of mdxF significantly reduced enterococcal colonization and/or survival in kidneys and liver of mice after intraperitoneal infection.IMPORTANCE Infections by enterococci, which are major health care-associated pathogens, are difficult to treat due to their increasing resistance to clinically

  17. Antimicrobial efficacy of photodynamic therapy, Nd:YAG laser and QMiX solution against Enterococcus faecalis biofilm.

    PubMed

    Bago Jurič, Ivona; Plečko, Vanda; Anić, Ivica; Pleško, Sanja; Jakovljević, Suzana; Rocca, Jean Paul; Medioni, Etienne

    2016-03-01

    Lasers have been recommended in final root canal disinfection protocol, however, there is no clear evidence about their efficacy against bacteria in biofilms. The aim of the study was to evaluate and compare the disinfection effect of antimicrobial photodynamic therapy (aPDT), Nd:YAG laser and QMiX solution against Enterococcus faecalis biofilm. The study sample consisted of 65 dentine slices, which were inoculated with E. faecalis and incubated anaerobically for three weeks. The dentine discs were randomly allocated to one of the following experimental groups: aPDT (100 mW, 10 mg/ml phenothiazinium chloride, 1 min), Nd:YAG laser (2 W, 15 Hz, 4×5 s), QMiX solution (1 min). Positive controls did not receive any treatment and negative controls were treated with 5.25% NaOCl. To harvest surviving adherent cells, each dentine sample was transffered to a test tube containing of TSB, serial ten-fold dilutions were made and aliquot of 1 ml was plated onto blood agar plates and incubated for 48 h. Colony forming units grown were counted and transformed into actual counts based on the dilution factor. The remaining viable cells after each protocol were analysed by FISH. The aPDT and the QMiX solution were equally effective, with the reduction rate of E. faecalis CFUs of 98.8% and 99.3% respectively (p=1.107). The Nd:YAG laser caused 96% reduction of E. faecalis (P<0.001). The aPDT and the QMiX solution showed similar antibacterial efficacy against old E. faecalis biofilm, followed by Nd:YAG irradiation. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Ultrasonic activation and chemical modification of photosensitizers enhances the effects of photodynamic therapy against Enterococcus faecalis root-canal isolates.

    PubMed

    Tennert, C; Drews, A M; Walther, V; Altenburger, M J; Karygianni, L; Wrbas, K T; Hellwig, E; Al-Ahmad, A

    2015-06-01

    The aim of this study was to evaluate the effect of photodynamic therapy (PDT) on Enterococcus faecalis biofilms in artificially infected root canals using modified photosensitizers and passive ultrasonic activation. Two hundred and seventy extracted human teeth with one root canal were instrumented utilizing ProTaper files, autoclaved, infected with E. faecalis T9 for 72 h and divided into different groups: irrigation with 3% sodium hypochlorite (NaOCl), 20% ethylenediaminetetraacetic acid (EDTA), or 20% citric acid, PDT without irrigation, PDT accompanied by irrigation with NaOCl, EDTA, or citric acid, PDT using an EDTA-based photosensitizer or a citric-acid-based photosensitizer and PDT with ultrasonic activation of the photosensitizer. A 15 mg/ml toluidine blue served as the photosensitizer, activated by a 100 mW LED light source. Sterile paper points were used for sampling the root canals and dentin chips were collected to assess the remaining contamination after treatment. Samples were cultured on blood agar plates and colony forming units were quantified. PDT alone achieved a reduction in E. faecalis counts by 92.7%, NaOCl irrigation alone and combined with PDT by 99.9%. The antibacterial effects increased by the combination of irrigation using EDTA or citric acid and PDT compared to irrigation alone. More than 99% of E. faecalis were killed using PDT with the modified photosensitizers and ultrasonic activation. NaOCl based disinfection achieved the highest antimicrobial effect. Using PDT with an EDTA-based or citric-acid-based phozosensitizer or activating the photosensitizer with ultrasound resulted in a significantly higher reduction in E. faecalis counts compared to conventional PDT. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Incongruence between the cps type 2 genotype and host-related phenotypes of an Enterococcus faecalis food isolate.

    PubMed

    Gaspar, Frédéric Bustos; Montero, Natalia; Akary, Elodie; Teixeira, Neuza; Matos, Renata; Gonzalez-Zorn, Bruno; Barreto Crespo, Maria Teresa; Serror, Pascale; Silva Lopes, Maria de Fátima

    2012-08-17

    Enterococcus faecalis is a nosocomial opportunistic pathogen, but is also found in fermented food products where it plays a fundamental role in the fermentation process. Previously, we have described the non-starter E. faecalis cheese isolate QA29b as harboring virulence genes and proven to be virulent in Galleria mellonella virulence model. In this study, we further characterized this food strain concerning traits relevant for the host-pathogen relationship. QA29b was found to belong to sequence type (ST) 72, a common ST among food isolates, and thus we consider it as a good representative of food E. faecalis strains. It demonstrated high ability to form biofilms, to adhere to epithelial cells and was readily eliminated by J774.A1 macrophage cells. Despite carrying the cps locus associated with the capsular polysaccharide CPS 2 type, cps genes were not expressed, likely due to an IS6770 inserted in the cpsC-cpsK promoter region. This work constitutes the first study of traits important for interaction, colonization and infection in the host performed on a good representative of E. faecalis food isolates. Reported results stress the need for a reliable serotyping assay of E. faecalis, as cps genotyping may not be reliable. Overall, QA29b characterization shows that despite its virulence potential in an insect model, this food strain is readily eliminated by mammalian macrophages. Thus, fine tuned approaches combining cellular and mammalian models are needed to address and elucidate the multifactorial aspect of virulence potential associated with food isolates.

  20. Role of mprF1 and mprF2 in the Pathogenicity of Enterococcus faecalis

    PubMed Central

    Bao, Yinyin; Sakinc, Tuerkan; Laverde, Diana; Wobser, Dominique; Benachour, Abdellah; Theilacker, Christian; Hartke, Axel; Huebner, Johannes

    2012-01-01

    Background Enterococcus faecalis is one of the leading causes of nosocomial infections. Due to its innate and acquired resistance to most antibiotics, identification of new targets for antimicrobial treatment of E. faecalis is a high priority. The multiple peptide resistance factor MprF, which was first described in Staphylococcus aureus, modifies phosphatidylglycerol with lysin and reduces the negative charge of the membrane, thus increasing resistance to cationic antimicrobial peptides. We studied the effect of mprF in E. faecalis regarding influence on bacterial physiology and virulence. Results Two putative mprF paralogs (mprF1 and mprF2) were identified in E. faecalis by BLAST search using the well-described S. aureus gene as a lead. Two deletion mutants in E. faecalis 12030 were created by homologous recombination. Analysis of both mutants by thin-layer chromatography showed that inactivation of mprF2 abolishes the synthesis of three distinct amino-phosphatidylglycerols (PGs). In contrast, deletion of mprF1 did not interfere with the biosynthesis of amino-PG. Inactivation of mprF2 increased susceptibility against several antimicrobial peptides and resulted in a 42% increased biofilm formation compared to wild-type mprF. However, resistance to opsonic killing was increased in the mutant, while virulence in a mouse bacteremia model was unchanged. Conclusion Our data suggest that only mprF2 is involved in the aminoacylation of PG in enterococci, and is probably responsible for synthesis of Lys-PG, Ala-PG, and Arg-PG, while mprF1 does not seem to have a role in aminoacylation. As in other Gram-positive pathogens, aminoacylation through MprF2 increases resistance against cationic antimicrobial peptides. Unlike mprF found in other bacteria, mprF2 does not seem to be a major virulence factor in enterococci. PMID:22723861

  1. Secondary Cell Wall Polymers of Enterococcus faecalis Are Critical for Resistance to Complement Activation via Mannose-binding Lectin*

    PubMed Central

    Geiss-Liebisch, Stefan; Rooijakkers, Suzan H. M.; Beczala, Agnieszka; Sanchez-Carballo, Patricia; Kruszynska, Karolina; Repp, Christian; Sakinc, Tuerkan; Vinogradov, Evgeny; Holst, Otto; Huebner, Johannes; Theilacker, Christian

    2012-01-01

    The complement system is part of our first line of defense against invading pathogens. The strategies used by Enterococcus faecalis to evade recognition by human complement are incompletely understood. In this study, we identified an insertional mutant of the wall teichoic acid (WTA) synthesis gene tagB in E. faecalis V583 that exhibited an increased susceptibility to complement-mediated killing by neutrophils. Further analysis revealed that increased killing of the mutant was due to a higher rate of phagocytosis by neutrophils, which correlated with higher C3b deposition on the bacterial surface. Our studies indicated that complement activation via the lectin pathway was much stronger on the tagB mutant compared with wild type. In concordance, we found an increased binding of the key lectin pathway components mannose-binding lectin and mannose-binding lectin-associated serine protease-2 (MASP-2) on the mutant. To understand the mechanism of lectin pathway inhibition by E. faecalis, we purified and characterized cell wall carbohydrates of E. faecalis wild type and V583ΔtagB. NMR analysis revealed that the mutant strain lacked two WTAs with a repeating unit of →6)[α-l-Rhap-(1→3)]β-d-GalpNAc-(1→5)-Rbo-1-P and →6) β-d-Glcp-(1→3) [α-d-Glcp-(1→4)]-β-d-GalpNAc-(1→5)-Rbo-1-P→, respectively (Rbo, ribitol). In addition, compositional changes in the enterococcal rhamnopolysaccharide were noticed. Our study indicates that in E. faecalis, modification of peptidoglycan by secondary cell wall polymers is critical to evade recognition by the complement system. PMID:22908219

  2. Enterococcus faecalis Produces Abundant Extracellular Structures Containing DNA in the Absence of Cell Lysis during Early Biofilm Formation

    PubMed Central

    Barnes, Aaron M. T.; Ballering, Katie S.; Leibman, Rachel S.; Wells, Carol L.; Dunny, Gary M.

    2012-01-01

    ABSTRACT Enterococcus faecalis is a common Gram-positive commensal bacterium of the metazoan gastrointestinal tract capable of biofilm formation and an opportunistic pathogen of increasing clinical concern. Dogma has held that biofilms are slow-growing structures, often taking days to form mature microcolonies. Here we report that extracellular DNA (eDNA) is an integral structural component of early E. faecalis biofilms (≤4 h postinoculation). Combining cationic dye-based biofilm matrix stabilization techniques with correlative immuno-scanning electron microscopy (SEM) and fluorescent techniques, we demonstrate that—in early E. faecalis biofilms—eDNA localizes to previously undescribed intercellular filamentous structures, as well as to thick mats of extruded extracellular matrix material. Both of these results are consistent with previous reports that early biofilms are exquisitely sensitive to exogenous DNase treatment. High-resolution SEM demonstrates a punctate labeling pattern in both structures, suggesting the presence of an additional, non-DNA constituent. Notably, the previously described fratricidal or lytic mechanism reported as the source of eDNA in older (≥24 h) E. faecalis biofilms does not appear to be at work under these conditions; extensive visual examination by SEM revealed a striking lack of lysed cells, and bulk biochemical assays also support an absence of significant lysis at these early time points. In addition, some cells demonstrated eDNA labeling localized at the septum, suggesting the possibility of DNA secretion from metabolically active cells. Overall, these data are consistent with a model in which a subpopulation of viable E. faecalis cells secrete or extrude DNA into the extracellular matrix. PMID:22829679

  3. In vitro evaluation of antibacterial effect of AH Plus incorporated with quaternary ammonium epoxy silicate against Enterococcus faecalis.

    PubMed

    Gong, Shi-Qiang; Huang, Zhi-Bin; Shi, Wei; Ma, Bo; Tay, Franklin R; Zhou, Bin

    2014-10-01

    The purpose of this study was to evaluate the in vitro antibacterial effect of AH Plus (Dentsply, DeTrey, Konstanz, Germany) incorporated with quaternary ammonium epoxy silicate (QAES) against Enterococcus faecalis. QAES particles were synthesized by the cocondensation of tetraethoxysilane with 2 trialkoxysilanes (3-[trimethoxysilyl]propyldimethyloctadecyl ammonium chloride and 3-glycidyloxypropyltrimethoxysilane) through a 1-pot sol-gel route. Dried QAES particles were then characterized by attenuated total reflection Fourier transform infrared spectroscopy and scanning electron microscopy. AH Plus sealers incorporated with 0-8 wt% QAES were tested after 4 weeks of water aging to assess the in vitro antibacterial activity against E. faecalis by the direct contact test (DCT) and 3-dimensional image analysis of live/dead-stained E. faecalis biofilms using confocal laser scanning microscopy. The Fourier transform infrared spectroscopy spectrum of QAES particles revealed the coexistence of the characteristic absorbance band of the siloxane backbone (Si-O-Si) from 1,000-1,100 cm(-1), epoxide band peaking at ∼916 cm(-1), and C-N stretching vibration peaking at 1,373 cm(-1). The scanning electron microscopic image showed the spherical morphology of QAES particles with ∼120 nm in diameter and a rough surface. DCT results revealed that AH Plus alone (0 wt% QAES) after 4 weeks of water aging had no inhibitory effect on E. faecalis growth (P = .569). AH Plus incorporated with QAES (2-8 wt%) showed antibacterial activity against E. faecalis as shown in DCT and biofilm viability results (P < .001). The incorporation of QAES into epoxy resin-based AH Plus may be a promising approach for controlling endodontic infection at the time of canal filling and preventing subsequent reinfection. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  4. Frequencies of resistance to Melaleuca alternifolia (tea tree) oil and rifampicin in Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis.

    PubMed

    Hammer, Katherine A; Carson, Christine F; Riley, Thomas V

    2008-08-01

    This study was conducted to determine the frequencies at which single-step mutants resistant to tea tree oil and rifampicin occurred amongst the Gram-positive organisms Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis. For tea tree oil, resistance frequencies were very low at <10(-9). Single-step mutants resistant to tea tree oil were undetectable at two times the minimum inhibitory concentration (MIC) for S. aureus RN4220 and derivative mutator strains or at 3 x MIC for the remaining S. aureus strains, including a clinical meticillin-resistant S. aureus isolate. Similarly, no mutants were recovered at 2x MIC for S. epidermidis or at 1x MIC for E. faecalis. Resistance frequencies determined in vitro for rifampicin (8 x MIC) ranged from 10(-7) to 10(-8) for all isolates, with the exception of the S. aureus mutator strains, which had slightly higher frequencies. These data suggest that Gram-positive organisms such as Staphylococcus and Enterococcus spp. have very low frequencies of resistance to tea tree oil.

  5. Characterization of dihydrofolate reductase genes from trimethoprim-susceptible and trimethoprim-resistant strains of Enterococcus faecalis.

    PubMed

    Coque, T M; Singh, K V; Weinstock, G M; Murray, B E

    1999-01-01

    Enterococci are usually susceptible in vitro to trimethoprim; however, high-level resistance (HLR) (MICs, >1,024 microg/ml) has been reported. We studied Enterococcus faecalis DEL, for which the trimethoprim MIC was >1,024 microg/ml. No transfer of resistance was achieved by broth or filter matings. Two different genes that conferred trimethoprim resistance when they were cloned in Escherichia coli (MICs, 128 and >1,024 microg/ml) were studied. One gene that coded for a polypeptide of 165 amino acids (MIC, 128 microg/ml for E. coli) was identical to dfr homologs that we cloned from a trimethoprim-susceptible E. faecalis strain, and it is presumed to be the intrinsic E. faecalis dfr gene (which causes resistance in E. coli when cloned in multiple copies); this gene was designated dfrE. The nucleotide sequence 5' to this dfr gene showed similarity to thymidylate synthetase genes, suggesting that the dfr and thy genes from E. faecalis are located in tandem. The E. faecalis gene that conferred HLR to trimethoprim in E. coli, designated dfrF, codes for a predicted polypeptide of 165 amino acids with 38 to 64% similarity with other dihydrofolate reductases from gram-positive and gram-negative organisms. The nucleotide sequence 5' to dfrF did not show similarity to the thy sequences. A DNA probe for dfrF hybridized under high-stringency conditions only to colony lysates of enterococci for which the trimethoprim MIC was >1,024 microg/ml; there was no hybridization to plasmid DNA from the strain of origin. To confirm that this gene causes trimethoprim resistance in enterococci, we cloned it into the integrative vector pAT113 and electroporated it into RH110 (E. faecalis OG1RF::Tn916DeltaEm) (trimethoprim MIC, 0.5 microg/ml), which resulted in RH110 derivatives for which the trimethoprim MIC was >1, 024 microg/ml. These results indicate that dfrF is an acquired but probably chromosomally located gene which is responsible for in vitro HLR to trimethoprim in E. faecalis.

  6. Efficacy of Ampicillin plus Ceftriaxone in Treatment of Experimental Endocarditis Due to Enterococcus faecalis Strains Highly Resistant to Aminoglycosides

    PubMed Central

    Gavaldà, Joan; Torres, Carmen; Tenorio, Carmen; López, Pedro; Zaragoza, Myriam; Capdevila, Josep A.; Almirante, Benito; Ruiz, Fernanda; Borrell, Nuria; Gomis, Xavier; Pigrau, Carles; Baquero, Fernando; Pahissa, Albert

    1999-01-01

    The purpose of this work was to evaluate the in vitro possibilities of ampicillin-ceftriaxone combinations for 10 Enterococcus faecalis strains with high-level resistance to aminoglycosides (HLRAg) and to assess the efficacy of ampicillin plus ceftriaxone, both administered with humanlike pharmacokinetics, for the treatment of experimental endocarditis due to HLRAg E. faecalis. A reduction of 1 to 4 dilutions in MICs of ampicillin was obtained when ampicillin was combined with a fixed subinhibitory ceftriaxone concentration of 4 μg/ml. This potentiating effect was also observed by the double disk method with all 10 strains. Time-kill studies performed with 1 and 2 μg of ampicillin alone per ml or in combination with 5, 10, 20, 40, and 60 μg of ceftriaxone per ml showed a ≥2 log10 reduction in CFU per milliliter with respect to ampicillin alone and to the initial inoculum for all 10 E. faecalis strains studied. This effect was obtained for seven strains with the combination of 2 μg of ampicillin per ml plus 10 μg of ceftriaxone per ml and for six strains with 5 μg of ceftriaxone per ml. Animals with catheter-induced endocarditis were infected intravenously with 108 CFU of E. faecalis V48 or 105 CFU of E. faecalis V45 and were treated for 3 days with humanlike pharmacokinetics of 2 g of ampicillin every 4 h, alone or combined with 2 g of ceftriaxone every 12 h. The levels in serum and the pharmacokinetic parameters of the humanlike pharmacokinetics of ampicillin or ceftriaxone in rabbits were similar to those found in humans treated with 2 g of ampicillin or ceftriaxone intravenously. Results of the therapy for experimental endocarditis caused by E. faecalis V48 or V45 showed that the residual bacterial titers in aortic valve vegetations were significantly lower in the animals treated with the combinations of ampicillin plus ceftriaxone than in those treated with ampicillin alone (P < 0.001). The combination of ampicillin and ceftriaxone showed in vitro and

  7. Partial Diversity Generates Effector Immunity Specificity of the Bac41-Like Bacteriocins of Enterococcus faecalis Clinical Strains

    PubMed Central

    Kurushima, Jun; Ike, Yasuyoshi

    2016-01-01

    ABSTRACT Bacteriocin 41 (Bac41) is the plasmid-encoded bacteriocin produced by the opportunistic pathogen Enterococcus faecalis. Its genetic determinant consists of bacL1 (effector), bacL2 (regulator), bacA (effector), and bacI (immunity). The secreted effectors BacL1 and BacA coordinate to induce the lytic cell death of E. faecalis. Meanwhile, the immunity factor BacI provides self-resistance to the Bac41 producer, E. faecalis, against the action of BacL1 and BacA. In this study, we demonstrated that more than half of the 327 clinical strains of E. faecalis screened had functional Bac41 genes. Analysis of the genetic structure of the Bac41 genes in the DNA sequences of the E. faecalis strains revealed that the Bac41-like genes consist of a relatively conserved region and a variable region located downstream from bacA. Based on similarities in the variable region, the Bac41-like genes could be classified into type I, type IIa, and type IIb. Interestingly, the distinct Bac41 types had specific immunity factors for self-resistance, BacI1 or BacI2, and did not show cross-immunity to the other type of effector. We also demonstrated experimentally that the specificity of the immunity was determined by the combination of the C-terminal region of BacA and the presence of the unique BacI1 or BacI2 factor. These observations suggested that Bac41-like bacteriocin genes are extensively disseminated among E. faecalis strains in the clinical environment and can be grouped into at least three types. It was also indicated that the partial diversity results in specificity of self-resistance which may offer these strains a competitive advantage. IMPORTANCE Bacteriocins are antibacterial effectors produced by bacteria. In general, a bacteriocin-coding gene is accompanied by a cognate immunity gene that confers self-resistance on the bacteriocin-producing bacterium itself. We demonstrated that one of the bacteriocins, Bac41, is disseminated among E. faecalis clinical strains and the

  8. Molecular Mechanism of Quorum-Sensing in Enterococcus faecalis: Its Role in Virulence and Therapeutic Approaches.

    PubMed

    Ali, Liaqat; Goraya, Mohsan Ullah; Arafat, Yasir; Ajmal, Muhammad; Chen, Ji-Long; Yu, Daojin

    2017-05-03

    Quorum-sensing systems control major virulence determinants in Enterococcusfaecalis, which causes nosocomial infections. The E. faecalis quorum-sensing systems include several virulence factors that are regulated by the cytolysin operon, which encodes the cytolysin toxin. In addition, the E. faecalis Fsr regulator system controls the expression of gelatinase, serine protease, and enterocin O16. The cytolysin and Fsr virulence factor systems are linked to enterococcal diseases that affect the health of humans and other host models. Therefore, there is substantial interest in understanding and targeting these regulatory pathways to develop novel therapies for enterococcal infection control. Quorum-sensing inhibitors could be potential therapeutic agents for attenuating the pathogenic effects of E. faecalis. Here, we discuss the regulation of cytolysin, the LuxS system, and the Fsr system, their role in E. faecalis-mediated infections, and possible therapeutic approaches to prevent E. faecalis infection.

  9. Biochemical and Structural Basis for Inhibition of Enterococcus faecalis Hydroxymethylglutaryl-CoA Synthase, mvaS, by Hymeglusin

    SciTech Connect

    Skaff, D. Andrew; Ramyar, Kasra X.; McWhorter, William J.; Barta, Michael L.; Geisbrecht, Brian V.; Miziorko, Henry M.

    2012-07-25

    Hymeglusin (1233A, F244, L-659-699) is established as a specific {beta}-lactone inhibitor of eukaryotic hydroxymethylglutaryl-CoA synthase (HMGCS). Inhibition results from formation of a thioester adduct to the active site cysteine. In contrast, the effects of hymeglusin on bacterial HMG-CoA synthase, mvaS, have been minimally characterized. Hymeglusin blocks growth of Enterococcus faecalis. After removal of the inhibitor from culture media, a growth curve inflection point at 3.1 h is observed (vs 0.7 h for the uninhibited control). Upon hymeglusin inactivation of purified E. faecalis mvaS, the thioester adduct is more stable than that measured for human HMGCS. Hydroxylamine cleaves the thioester adduct; substantial enzyme activity is restored at a rate that is 8-fold faster for human HMGCS than for mvaS. Structural results explain these differences in enzyme-inhibitor thioester adduct stability and solvent accessibility. The E. faecalis mvaS-hymeglusin cocrystal structure (1.95 {angstrom}) reveals virtually complete occlusion of the bound inhibitor in a narrow tunnel that is largely sequestered from bulk solvent. In contrast, eukaryotic (Brassica juncea) HMGCS binds hymeglusin in a more solvent-exposed cavity.

  10. Effects Of Myrcia Ovata Cambess. Essential Oil On Planktonic Growth Of Gastrointestinal Microorganisms and Biofilm Formation Of Enterococcus Faecalis

    PubMed Central

    Cândido, Cinthya S.; Portella, Cadmo Silton A.; Laranjeira, Bruno J.; da Silva, Sérgio S.; Arriaga, Angela M.C.; Santiago, Gilvandete M. P.; Gomes, Geovany A.; Almeida, Paulo César; Carvalho, Cibele B. M.

    2010-01-01

    The essential oil from the leaves of Myrcia ovata Cambess., commonly used in Brazil for the treatment of gastric illnesses, was screened for antimicrobial activity and action in the formation of microbial biofilms by Enterococcus faecalis. The oil was obtained by hydrodistillation using a clevenger-type system. Its chemical composition was analyzed using GC and GC-MS. Both MIC and MBC of the essential oil were determined by broth microdilution techniques and agar dilution method. The essential oil showed antimicrobial activity against E. faecalis, Escherichia coli, Pseudomonas aeruginosa, Salmonella choleraesuis, Staphylococcus aureus, Streptococcus pneumoniae and Candida parapsilosis. The results showed that the essential oil of M. ovata Cambess. was effective against the formation of biofilm by E. faecalis when compared with the control. Four volatile compounds, representing 92.1 % of the oil, were identified and geranial was the major component (50.4 %). At the best of our knowledge, this is the first report of the chemical composition and antimicrobial activity of the essential oil from leaves of M. ovata. PMID:24031537

  11. Atomic force microscopy visualization of injuries in Enterococcus faecalis surface caused by Er,Cr:YSGG and diode lasers.

    PubMed

    López-Jiménez, Lidia; Arnabat-Domínguez, Josep; Viñas, Miguel; Vinuesa, Teresa

    2015-01-01

    To visualize by atomic force microscopy the alterations induced on Enterococcus. faecalis surface after treatment with 2 types of laser: Erbium chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser and Diode laser. Bacterial suspensions from overnight cultures of E. faecalis were irradiated during 30 seconds with the laser-lights at 1 W and 2 W of power, leaving one untreated sample as control. Surface alterations on treated E. faecalis were visualized by atomic force microscopy (AFM) and its surface roughness determined. AFM imaging showed that at high potency of laser both cell morphology and surface roughness resulted altered, and that several cell lysis signs were easily visualized. Surface roughness clearly increase after the treatment with Er,Cr:YSGG at 2W of power, while the other treatments gave similar values of surface roughness. The effect of lasers on bacterial surfaces visualized by AFM revealed drastic alterations. AFM is a good tool to evaluate surface injuries after laser treatment; and could constitute a measure of antimicrobial effect that can complete data obtained by determination of microbial viability.

  12. Effectiveness of repeated photodynamic therapy in the elimination of intracanal Enterococcus faecalis biofilm: an in vitro study.

    PubMed

    Prażmo, Ewa Joanna; Godlewska, Renata Alicja; Mielczarek, Agnieszka Beata

    2017-04-01

    The study aimed to investigate the effectiveness of photodynamic therapy in the elimination of intracanal Enterococcus faecalis biofilm and to analyse how a repeated light irradiation, replenishment of oxygen and photosensitiser affect the results of the photodynamic disinfecting protocol. After chemomechanical preparation, 46 single-rooted human teeth were infected with a clinical strain of E. faecalis and incubated for a week in microaerobic conditions. The experimental procedures included groups of single application of photodynamic therapy, two cycles of PDT, irrigation with 5.25% NaOCl solution and negative and positive control. The number of residing bacterial colonies in the root canals was determined based on the CFU/ml method. In the group of preparations irrigated with NaOCl, bacterial colonies were not observed. A single PDT eliminated 45% of the initial CFU/ml. Repeated PDT eradicated 95% of the intracanal bacterial biofilm. Photodynamic therapy has a high potential for the elimination of E. faecalis biofilm. There is a safe therapeutic window where photoinduced disinfection can be used as an adjuvant to conventional endodontic treatment, which remains the most effective.

  13. EC300: a phage-based, bacteriolysin-like protein with enhanced antibacterial activity against Enterococcus faecalis.

    PubMed

    Proença, Daniela; Leandro, Clara; Garcia, Miguel; Pimentel, Madalena; São-José, Carlos

    2015-06-01

    Bacteriophage lytic enzymes, either endolysins or virion-associated lysins, have been receiving considerable attention as potential antibacterial agents, particularly for the combat of antibiotic-resistant Gram-positive pathogens. A conclusion that easily emerges from the careful analysis of a great number of reports on the field is that the activity of phage lytic enzymes is rarely studied in conditions that support robust growth of the target bacteria. Here, we report the construction and study of a chimerical lysin, EC300, which was designed to target and kill Enterococcus faecalis in conditions supporting vigorous bacterial growth. EC300 resulted from the fusion of a predicted M23 endopeptidase domain of a virion-associated lysin to the putative cell wall binding domain of a previously characterized amidase endolysin, both produced by the E. faecalis phage F170/08. This bacteriolysin-like protein exhibited a clear enhanced lytic activity over the parental endolysin when both were assayed in a rich bacterial growth medium. We demonstrate the killing efficacy of EC300 against growing cells of a panel of typed E. faecalis clinical strains with high level of antibiotic resistance. The possible reasons for the marked difference between the lytic performance of EC300 and that of the amidase are discussed.

  14. Role of Serum, a Biological Cue, in Adherence of Enterococcus faecalis to Extracellular Matrix Proteins, Collagen, Fibrinogen, and Fibronectin

    PubMed Central

    Nallapareddy, Sreedhar R.; Murray, Barbara E.

    2009-01-01

    Background Most previous reports have found that Enterococcus faecalis isolates do not show significant adherence to fibronectin and fibrinogen Methods The influence of various conditions on E. faecalis adherence to ECM proteins was evaluated using a radiolabeled adherence assay. Results Among conditions studied, growth in 40% serum, a biological cue with potential clinical relevance, elicited adherence of all 46 E. faecalis strains tested to fibronectin and fibrinogen, but not to elastin; the adherence levels were independent of strain source and was eliminated by treating cells with trypsin. As previously reported, serum also elicited collagen adherence. While prolonged exposure to serum during growth was needed for enhancement of adherence to fibrinogen, brief exposure (<5 min) to serum had an immediate, although partial, effect on adherence to fibronectin and collagen. Pre-treatment of bacteria with chloramphenicol did not decrease the enhanced fibronectin and collagen adherence, indicating that protein synthesis is not required for the latter effect. Conclusion Together, these data suggest that serum components may serve i) as host environmental stimuli to induce production of extracellular matrix protein binding adhesin(s), as previously seen with collagen adherence, and also ii) as activators of adherence, perhaps by forming bridges between ECM proteins and adhesins. PMID:18462135

  15. Comparative Antimicrobial Efficacy of Eucalyptus Galbie and Myrtus Communis L. Extracts, Chlorhexidine and Sodium Hypochlorite against Enterococcus Faecalis.

    PubMed

    Nourzadeh, Mahdieh; Amini, Arezu; Fakoor, Farzaneh; Raoof, Maryam; Sharififar, Fariba

    2017-01-01

    The aim of this study was to evaluate the antimicrobial effect of Eucalyptusgalbie and Myrtus communis L. methanolic extracts, chlorhexidine (CHX) and sodium hypochlorite (NaOCl) on Enterococcus faecalis (E. faecalis) as the predominant species isolated from infected root canals. One hundred twenty mandibular premolars were randomly divided into 8 groups: Eucalyptusgalbie (E. galbie) 12.5 mg/mL, Myrtus communis L. (M. communis L.) 6.25 mg/mL, 0.2% CHX, %2 CHX, 2.5% NaOCl, 5.25% NaOCl, positive and negative control group. Sampling was performed using paper points (from the root canal space lumen) and Gates-Glidden drills (from the dentinal tubules); then colony forming units (CFU) were counted and analyzed using the Kruskal-Wallis test, followed by Mann Whitney U test. The level of significance was set at 0.05. All irrigants reduced more than 99% of bacteria in root canal. In the presence of M. communis L. and E. galbie, the bacterial count in dentin were significantly more than CHX and NaOCl groups (P<0.05) except 0.2% CHX in 200 µm and 400 µm depths (P>0.05). Although 5.25% NaOCl was the most effective irrigant, all agents exerted acceptable antimicrobial activity against E. faecalis.

  16. Effects of myrcia ovata cambess. Essential oil on planktonic growth of gastrointestinal microorganisms and biofilm formation of enterococcus faecalis.

    PubMed

    Cândido, Cinthya S; Portella, Cadmo Silton A; Laranjeira, Bruno J; da Silva, Sérgio S; Arriaga, Angela M C; Santiago, Gilvandete M P; Gomes, Geovany A; Almeida, Paulo César; Carvalho, Cibele B M

    2010-07-01

    The essential oil from the leaves of Myrcia ovata Cambess., commonly used in Brazil for the treatment of gastric illnesses, was screened for antimicrobial activity and action in the formation of microbial biofilms by Enterococcus faecalis. The oil was obtained by hydrodistillation using a clevenger-type system. Its chemical composition was analyzed using GC and GC-MS. Both MIC and MBC of the essential oil were determined by broth microdilution techniques and agar dilution method. The essential oil showed antimicrobial activity against E. faecalis, Escherichia coli, Pseudomonas aeruginosa, Salmonella choleraesuis, Staphylococcus aureus, Streptococcus pneumoniae and Candida parapsilosis. The results showed that the essential oil of M. ovata Cambess. was effective against the formation of biofilm by E. faecalis when compared with the control. Four volatile compounds, representing 92.1 % of the oil, were identified and geranial was the major component (50.4 %). At the best of our knowledge, this is the first report of the chemical composition and antimicrobial activity of the essential oil from leaves of M. ovata.

  17. Antimicrobial activity of Chlorhexidine, Peracetic acid and Sodium hypochlorite/etidronate irrigant solutions against Enterococcus faecalis biofilms.

    PubMed

    Arias-Moliz, M T; Ordinola-Zapata, R; Baca, P; Ruiz-Linares, M; García García, E; Hungaro Duarte, M A; Monteiro Bramante, C; Ferrer-Luque, C M

    2015-12-01

    To evaluate the antimicrobial effect of 2.5% sodium hypochlorite alone (NaOCl) and associated with 9% HEBP (NaOCl/HEBP), 2% peracetic acid (PAA) and 2% chlorhexidine (CHX), on the viability of Enterococcus faecalis biofilms attached to dentine. Biofilms of E. faecalis were grown on the surface of dentine blocks for 5 days and then exposed to the irrigating solutions for 3 min. Distilled water was used as the control. The total biovolume and the percentage of dead cells of the infected dentine were measured by means of confocal microscopy and the live/dead technique. Nonparametric tests were used to determine statistical differences (P < 0.05). NaOCl and the NaOCl/HEBP mixture were associated with a significantly greater percentage of dead cells, followed by PAA (P < 0.05). No significant antimicrobial effect of CHX was observed in comparison with the control group. Total biovolume decreased significantly in NaOCl, NaOCl/HEBP and PAA solutions in comparison with the CHX and control groups. NaOCl alone or associated with HEBP were the most effective irrigant solutions in dissolving and killing E. faecalis biofilms. © 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  18. Adaptation to NaCl Reduces the Susceptibility of Enterococcus faecalis to Melaleuca alternifolia (Tea Tree) Oil.

    PubMed

    Lim, Ee Lin; Hammer, Katherine Ann

    2015-10-01

    This study investigated the hypothesis that the salt adaptation response of Enterococcus faecalis alters susceptibility to tea tree oil (TTO). Six E. faecalis isolates were adapted to 6.5 % NaCl, and then exposed to TTO in phosphate-buffered saline (PBS). One isolate was also exposed to TTO in Brain Heart Infusion Broth (BHIB). The viability of salt-adapted and non-adapted control cells was determined at 0, 45 and 90 min and compared. MICs for several antibiotics and TTO were also determined by E test and broth microdilution, respectively. Results showed that susceptibility to TTO in PBS was significantly reduced after salt adaptation for five isolates (83 %) (P < 0.05). Mean differences between salt-adapted and non-adapted cell counts were 2.51 log at 45 min and 2.13 log at 90 min. However, when E. faecalis ATCC 19433 was exposed to TTO in BHIB, no significant differences were seen. In conclusion, salt adaptation resulted in reduced susceptibility to TTO in PBS for the majority of isolates, indicating that cross protection had occurred. This effect was absent in BHIB, suggesting that the uptake of compatible solutes from the growth medium protected non-adapted cells from TTO. Whether this has implications for the clinical effectiveness of TTO remains to be determined.

  19. Mortality in kittens is associated with a shift in ileum mucosa-associated enterococci from Enterococcus hirae to biofilm-forming Enterococcus faecalis and adherent Escherichia coli.

    PubMed

    Ghosh, Anuradha; Borst, Luke; Stauffer, Stephen H; Suyemoto, Mitsu; Moisan, Peter; Zurek, Ludek; Gookin, Jody L

    2013-11-01

    Approximately 15% of foster kittens die before 8 weeks of age, with most of these kittens demonstrating clinical signs or postmortem evidence of enteritis. While a specific cause of enteritis is not determined in most cases, these kittens are often empirically administered probiotics that contain enterococci. The enterococci are members of the commensal intestinal microbiota but also can function as opportunistic pathogens. Given the complicated role of enterococci in health and disease, it would be valuable to better understand what constitutes a "healthy" enterococcal community in these kittens and how this microbiota is impacted by severe illness. In this study, we characterized the ileum mucosa-associated enterococcal community of 50 apparently healthy and 50 terminally ill foster kittens. In healthy kittens, Enterococcus hirae was the most common species of ileum mucosa-associated enterococci and was often observed to adhere extensively to the small intestinal epithelium. These E. hirae isolates generally lacked virulence traits. In contrast, non-E. hirae enterococci, notably Enterococcus faecalis, were more commonly isolated from the ileum mucosa of kittens with terminal illness. Isolates of E. faecalis had numerous virulence traits and multiple antimicrobial resistances. Moreover, the attachment of Escherichia coli to the intestinal epithelium was significantly associated with terminal illness and was not observed in any kitten with adherent E. hirae. These findings identify a significant difference in the species of enterococci cultured from the ileum mucosa of kittens with terminal illness compared to the species cultured from healthy kittens. In contrast to prior case studies that associated enteroadherent E. hirae with diarrhea in young animals, these controlled studies identified E. hirae as more often isolated from healthy kittens and adherence of E. hirae as more common and extensive in healthy kittens than in sick kittens.

  20. Mortality in Kittens Is Associated with a Shift in Ileum Mucosa-Associated Enterococci from Enterococcus hirae to Biofilm-Forming Enterococcus faecalis and Adherent Escherichia coli

    PubMed Central

    Ghosh, Anuradha; Borst, Luke; Stauffer, Stephen H.; Suyemoto, Mitsu; Moisan, Peter; Zurek, Ludek

    2013-01-01

    Approximately 15% of foster kittens die before 8 weeks of age, with most of these kittens demonstrating clinical signs or postmortem evidence of enteritis. While a specific cause of enteritis is not determined in most cases, these kittens are often empirically administered probiotics that contain enterococci. The enterococci are members of the commensal intestinal microbiota but also can function as opportunistic pathogens. Given the complicated role of enterococci in health and disease, it would be valuable to better understand what constitutes a “healthy” enterococcal community in these kittens and how this microbiota is impacted by severe illness. In this study, we characterized the ileum mucosa-associated enterococcal community of 50 apparently healthy and 50 terminally ill foster kittens. In healthy kittens, Enterococcus hirae was the most common species of ileum mucosa-associated enterococci and was often observed to adhere extensively to the small intestinal epithelium. These E. hirae isolates generally lacked virulence traits. In contrast, non-E. hirae enterococci, notably Enterococcus faecalis, were more commonly isolated from the ileum mucosa of kittens with terminal illness. Isolates of E. faecalis had numerous virulence traits and multiple antimicrobial resistances. Moreover, the attachment of Escherichia coli to the intestinal epithelium was significantly associated with terminal illness and was not observed in any kitten with adherent E. hirae. These findings identify a significant difference in the species of enterococci cultured from the ileum mucosa of kittens with terminal illness compared to the species cultured from healthy kittens. In contrast to prior case studies that associated enteroadherent E. hirae with diarrhea in young animals, these controlled studies identified E. hirae as more often isolated from healthy kittens and adherence of E. hirae as more common and extensive in healthy kittens than in sick kittens. PMID:23966487

  1. β-Lactams enhance daptomycin activity against vancomycin-resistant Enterococcus faecalis and Enterococcus faecium in in vitro pharmacokinetic/pharmacodynamic models.

    PubMed

    Smith, Jordan R; Barber, Katie E; Raut, Animesh; Rybak, Michael J

    2015-05-01

    Enterococcus faecalis and Enterococcus faecium are frequently resistant to vancomycin and β-lactams. In enterococcal infections with reduced glycopeptide susceptibility, combination therapy is often administered. Our objective was to conduct pharmacokinetic/pharmacodynamic (PK/PD) models to evaluate β-lactam synergy with daptomycin (DAP) against resistant enterococci. One E. faecalis strain (R6981) and two E. faecium strains (R6370 and 8019) were evaluated. DAP MICs were obtained. All strains were evaluated for response to LL37, an antimicrobial peptide, in the presence and absence of ceftaroline (CPT), ertapenem (ERT), and ampicillin (AMP). After 96 h, in vitro models were run simulating 10 mg DAP/kg body weight/day, 600 mg CPT every 8 h (q8h), 2 g AMP q4h, and 1 g ERT q24h, both alone and in combination against all strains. DAP MICs were 2, 4, and 4 μg/ml for strains R6981, R6370, and 8019, respectively. PK/PD models demonstrated bactericidal activity with DAP-CPT, DAP-AMP, and DAP-ERT combinations against strain 8019 (P < 0.001 and log10 CFU/ml reduction of >2 compared to any single agent). Against strains R6981 and R6370, the DAP-AMP combination demonstrated enhancement against R6370 but not R6981, while the combinations of DAP-CPT and DAP-ERT were bactericidal, demonstrated enhancement, and were statistically superior to all other regimens at 96 h (P < 0.001) against both strains. CPT, ERT, and AMP similarly augmented LL37 killing against strain 8019. In strains R6981 and R6370, CPT and ERT aided LL37 more than AMP (P < 0.001). Compared to DAP alone, combination regimens provide better killing and prevent resistance. Clinical research involving DAP combinations is warranted. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  2. β-Lactams Enhance Daptomycin Activity against Vancomycin-Resistant Enterococcus faecalis and Enterococcus faecium in In Vitro Pharmacokinetic/Pharmacodynamic Models

    PubMed Central

    Smith, Jordan R.; Barber, Katie E.; Raut, Animesh

    2015-01-01

    Enterococcus faecalis and Enterococcus faecium are frequently resistant to vancomycin and β-lactams. In enterococcal infections with reduced glycopeptide susceptibility, combination therapy is often administered. Our objective was to conduct pharmacokinetic/pharmacodynamic (PK/PD) models to evaluate β-lactam synergy with daptomycin (DAP) against resistant enterococci. One E. faecalis strain (R6981) and two E. faecium strains (R6370 and 8019) were evaluated. DAP MICs were obtained. All strains were evaluated for response to LL37, an antimicrobial peptide, in the presence and absence of ceftaroline (CPT), ertapenem (ERT), and ampicillin (AMP). After 96 h, in vitro models were run simulating 10 mg DAP/kg body weight/day, 600 mg CPT every 8 h (q8h), 2 g AMP q4h, and 1 g ERT q24h, both alone and in combination against all strains. DAP MICs were 2, 4, and 4 μg/ml for strains R6981, R6370, and 8019, respectively. PK/PD models demonstrated bactericidal activity with DAP-CPT, DAP-AMP, and DAP-ERT combinations against strain 8019 (P < 0.001 and log10 CFU/ml reduction of >2 compared to any single agent). Against strains R6981 and R6370, the DAP-AMP combination demonstrated enhancement against R6370 but not R6981, while the combinations of DAP-CPT and DAP-ERT were bactericidal, demonstrated enhancement, and were statistically superior to all other regimens at 96 h (P < 0.001) against both strains. CPT, ERT, and AMP similarly augmented LL37 killing against strain 8019. In strains R6981 and R6370, CPT and ERT aided LL37 more than AMP (P < 0.001). Compared to DAP alone, combination regimens provide better killing and prevent resistance. Clinical research involving DAP combinations is warranted. PMID:25753639

  3. Effects of microgravity on the virulence of Listeria monocytogenes, Enterococcus faecalis, Candida albicans, and methicillin-resistant Staphylococcus aureus.

    PubMed

    Hammond, Timothy G; Stodieck, Louis; Birdsall, Holly H; Becker, Jeanne L; Koenig, Paul; Hammond, Jeffrey S; Gunter, Margaret A; Allen, Patricia L

    2013-11-01

    To evaluate effects of microgravity on virulence, we studied the ability of four common clinical pathogens--Listeria monocytogenes, methicillin-resistant Staphylococcus aureus (MRSA), Enterococcus faecalis, and Candida albicans--to kill wild type Caenorhabditis elegans (C. elegans) nematodes at the larval and adult stages. Simultaneous studies were performed utilizing spaceflight, clinorotation in a 2-D clinorotation device, and static ground controls. The feeding rate of worms for killed E. coli was unaffected by spaceflight or clinorotation. Nematodes, microbes, and growth media were separated until exposed to true or modeled microgravity, then mixed and grown for 48 h. Experiments were terminated by paraformaldehyde fixation, and optical density measurements were used to assay residual microorganisms. Spaceflight was associated with reduced virulence for Listeria, Enterococcus, MRSA, and Candida for both larval and adult C. elegans. These are the first data acquired with a direct in vivo assay system in space to demonstrate virulence. Clinorotation reproduced the effects of spaceflight in some, but not all, virulence assays: Candida and Enterococcus were less virulent for larval worms but not adult worms, whereas virulence of MRSA and Listeria were unaffected by clinorotation in tests with both adult and larval worms. We conclude that four common clinical microorganisms are all less virulent in space.

  4. Draft Genome Sequence of a Multidrug-Resistant Strain of Enterococcus faecalis, PM01, Isolated from the Nest of an American Bushtit, Psaltriparius minimus

    PubMed Central

    Esani, Saika; Constable, John V. H.

    2017-01-01

    ABSTRACT Pathogenic microorganisms associated with avian nests may detrimentally impact parental health and nest success for the nest primary users, potentially neighboring avian or terrestrial species, including humans. Here, we report the genome sequence of Enterococcus faecalis strain PM01, isolated from a failed nest of American bushtits, Psaltriparius minimus. PMID:28302771

  5. Characterization of Multi-Drug Resistant Enterococcus faecalis Isolated from Cephalic Recording Chambers in Research Macaques (Macaca spp.)

    PubMed Central

    Lebreton, Francois; Trowel, Elise; de la Fuente-Núñez, César; Dzink-Fox, Joanne; Gilmore, Michael S.; Fox, James G.

    2017-01-01

    Nonhuman primates are commonly used for cognitive neuroscience research and often surgically implanted with cephalic recording chambers for electrophysiological recording. Aerobic bacterial cultures from 25 macaques identified 72 bacterial isolates, including 15 Enterococcus faecalis isolates. The E. faecalis isolates displayed multi-drug resistant phenotypes, with resistance to ciprofloxacin, enrofloxacin, trimethoprim-sulfamethoxazole, tetracycline, chloramphenicol, bacitracin, and erythromycin, as well as high-level aminoglycoside resistance. Multi-locus sequence typing showed that most belonged to two E. faecalis sequence types (ST): ST 4 and ST 55. The genomes of three representative isolates were sequenced to identify genes encoding antimicrobial resistances and other traits. Antimicrobial resistance genes identified included aac(6’)-aph(2”), aph(3’)-III, str, ant(6)-Ia, tetM, tetS, tetL, ermB, bcrABR, cat, and dfrG, and polymorphisms in parC (S80I) and gyrA (S83I) were observed. These isolates also harbored virulence factors including the cytolysin toxin genes in ST 4 isolates, as well as multiple biofilm-associated genes (esp, agg, ace, SrtA, gelE, ebpABC), hyaluronidases (hylA, hylB), and other survival genes (ElrA, tpx). Crystal violet biofilm assays confirmed that ST 4 isolates produced more biofilm than ST 55 isolates. The abundance of antimicrobial resistance and virulence factor genes in the ST 4 isolates likely relates to the loss of CRISPR-cas. This macaque colony represents a unique model for studying E. faecalis infection associated with indwelling devices, and provides an opportunity to understand the basis of persistence of this pathogen in a healthcare setting. PMID:28081148

  6. Evaluation of Cold Plasma Treatment and Safety in Disinfecting 3-week Root Canal Enterococcus faecalis Biofilm In Vitro.

    PubMed

    Li, Yinglong; Sun, Ke; Ye, Guopin; Liang, Yongdong; Pan, Hong; Wang, Guomin; Zhao, Yijiao; Pan, Jie; Zhang, Jue; Fang, Jing

    2015-08-01

    Although endodontic infection is caused by multi-bacteria species, Enterococcus faecalis is usually isolated in chronic apical periodontitis. The aim of this study was to evaluate the effectiveness and mechanical safety of cold plasma therapy in disinfecting 3-week E. faecalis biofilms. Teeth with 3-week E. faecalis biofilm were treated with AC argon/oxygen (Ar/O2) cold plasma for various treatment times and compared with those treated with Ca(OH)2, 2% chlorhexidine gel, and Ca(OH)2/chlorhexidine for a week. Antimicrobial efficacy was assessed by colony-forming unit method. Scanning electron microscopy was used to assess the morphologic changes of E. faecalis biofilm by plasma. Confocal laser scanning microscopy was used to confirm the viability of the biofilm after the plasma treatment. Microhardness and roughness changes of root canal dentin caused by plasma were verified with Vickers Hardness Tester and 3D Profile Measurement Laser Microscope, respectively. There were no detectable live bacteria after 12 minutes of cold plasma treatment. This was further confirmed by scanning electron microscopy and confocal laser scanning microscopy results. Microhardness and roughness of root canal dentin showed no significant difference after plasma treatment. Atmospheric pressure cold plasma is an effective therapy in endodontics for its strong sterilization effect on fully matured biofilm within a few minutes. Meanwhile, it has an accepted mechanical safety for its low temperature and not affecting the microhardness and roughness of root canal dentin significantly. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  7. In vitro activity of daptomycin against Enterococcus faecalis under various conditions of growth-phases, inoculum and pH.

    PubMed

    Argemi, Xavier; Hansmann, Yves; Christmann, Daniel; Lefebvre, Sophie; Jaulhac, Benoit; Jehl, François

    2013-01-01

    Enterococcus faecalis (E. faecalis) has become a major leading cause of nosocomial endocarditis. Treatment of such infections remains problematic and new therapeutic options are needed. Nine E. faecalis strains were tested: six obtained from patients presenting endocarditis, one with isolated bacteremia, and two reference strains. Antibiotics included daptomycin, alone or in combination, linezolid, tigecycline, rifampicin, gentamicin, teicoplanin, ceftriaxone and amoxicillin. Time-kill studies included colony counts at 1, 4 and 24 h of incubation. Significant bactericidal activity was defined as a decrease of ≥3log10CFU/ml after 24 h of incubation. Antibiotics were tested at a low (10(6) CFU/ml) and high (10(9) CFU/ml) inoculum, against exponential- and stationary-phase bacteria. We also performed time kill studies of chemically growth arrested E. faecalis. Various pH conditions were used during the tests. In exponential growth phase and with a low inoculum, daptomycin alone at 60 µg/ml and the combination amoxicillin-gentamicin both achieved a 4-log10 reduction in one hour on all strains. In exponential growth phase with a high inoculum, daptomycin alone was bactericidal at a concentration of 120 µg/ml. All the combinations tested with this drug were indifferent. In stationary phase with a high inoculum daptomycin remained bactericidal but exhibited a pH dependent activity and slower kill rates. All combinations that did not include daptomycin were not bactericidal in conditions of high inoculum, whatever the growth phase. The results indicate that daptomycin is the only antibiotic that may be able of overcoming the effects of growth phase and high inoculum.

  8. Bacillus subtilis as a platform for molecular characterisation of regulatory mechanisms of Enterococcus faecalis resistance against cell wall antibiotics.

    PubMed

    Fang, Chong; Stiegeler, Emanuel; Cook, Gregory M; Mascher, Thorsten; Gebhard, Susanne

    2014-01-01

    To combat antibiotic resistance of Enterococcus faecalis, a better understanding of the molecular mechanisms, particularly of antibiotic detection, signal transduction and gene regulation is needed. Because molecular studies in this bacterium can be challenging, we aimed at exploiting the genetically highly tractable Gram-positive model organism Bacillus subtilis as a heterologous host. Two fundamentally different regulators of E. faecalis resistance against cell wall antibiotics, the bacitracin sensor BcrR and the vancomycin-sensing two-component system VanSB-VanRB, were produced in B. subtilis and their functions were monitored using target promoters fused to reporter genes (lacZ and luxABCDE). The bacitracin resistance system BcrR-BcrAB of E. faecalis was fully functional in B. subtilis, both regarding regulation of bcrAB expression and resistance mediated by the transporter BcrAB. Removal of intrinsic bacitracin resistance of B. subtilis increased the sensitivity of the system. The lacZ and luxABCDE reporters were found to both offer sensitive detection of promoter induction on solid media, which is useful for screening of large mutant libraries. The VanSB-VanRB system displayed a gradual dose-response behaviour to vancomycin, but only when produced at low levels in the cell. Taken together, our data show that B. subtilis is a well-suited host for the molecular characterization of regulatory systems controlling resistance against cell wall active compounds in E. faecalis. Importantly, B. subtilis facilitates the careful adjustment of expression levels and genetic background required for full functionality of the introduced regulators.

  9. Bactericidal Efficacy of Photodynamic Therapy and Chitosan in Root Canals Experimentally Infected with Enterococcus faecalis: An In Vitro Study.

    PubMed

    Camacho-Alonso, Fabio; Julián-Belmonte, Encarnación; Chiva-García, Fernando; Martínez-Beneyto, Yolanda

    2017-04-01

    To evaluate the antibacterial efficacy of photodynamic therapy (PDT) and chitosan against Enterococcus faecalis and assess the possible enhancive effect of chitosan on the photosensitizer methylene blue in experimentally infected root canals of extracted human teeth in vitro. E. faecalis is frequently found in persistent endodontic infections. In this context, the antimicrobial PDT or newer antibacterial alternatives such as chitosan could become modern alternatives to existing antibacterial treatment approaches. One hundred two single-rooted extracted teeth were used. The teeth were contaminated with 0.1 mL E. faecalis (3 × 10(8) cell/mL). These were randomized into six treatment groups (n = 17 teeth): Group 1 (2.5% NaOCl); Group 2 (PDT); Group 3 (chitosan 3 mg/mL); Group 4 (PDT+chitosan 3 mg/mL); Group 5 (positive control, no treatment); and Group 6 (negative control, no inoculation, no treatment). The canal content was sampled with sterile paper points. The samples were cultured on blood agar plates to determine the number of colony-forming units (CFU)/mL. Five teeth in each group were analyzed by scanning electron microscope (SEM) to determine the percentage of area with contamination and debris. The positive control group showed the highest number of CFU/mL, with statistically significant differences in comparison with the other treatment groups (p ≤ 0.05). Group 4 (PDT+chitosan) showed the lowest CFU/mL count, followed by Group 2 (PDT alone), which obtained similar results to Group 1 (NaOCl), but there was no significance between the treated groups. SEM images showed that Group 4 (PDT+Chitosan) showed the lowest area of contamination. Combination of PDT and chitosan showed antibacterial potential against endodontic infection by E. faecalis.

  10. Dietary Enterococcus faecalis LAB31 Improves Growth Performance, Reduces Diarrhea, and Increases Fecal Lactobacillus Number of Weaned Piglets

    PubMed Central

    Hu, Yuanliang; Dun, Yaohao; Li, Shenao; Zhang, Dongxiao; Peng, Nan; Zhao, Shumiao; Liang, Yunxiang

    2015-01-01

    Lactic acid bacteria (LAB) have been shown to enhance performance of weaned piglets. However, few studies have reported the addition of LAB Enterococcus faecalis as alternatives to growth promoting antibiotics for weaned piglets. This study evaluated the effects of dietary E. faecalis LAB31 on the growth performance, diarrhea incidence, blood parameters, fecal bacterial and Lactobacillus communities in weaned piglets. A total of 360 piglets weaned at 26 ± 2 days of age were randomly allotted to 5 groups (20 pens, with 4 pens for each group) for a trial of 28 days: group N (negative control, without antibiotics or probiotics); group P (Neomycin sulfate, 100 mg/kg feed); groups L, M and H (supplemented with E. faecalis LAB31 0.5×109, 1.0×109, and 2.5×109 CFU/kg feed, respectively). Average daily gain and feed conversion efficiency were found to be higher in group H than in group N, and showed significant differences between group H and group P (P0 < 0.05). Furthermore, groups H and P had a lower diarrhea index than the other three groups (P0 < 0.05). Denaturing gradient gel electrophoresis (DGGE) showed that the application of probiotics to the diet changed the bacterial community, with a higher bacterial diversity in group M than in the other four groups. Real-time PCR revealed that the relative number of Lactobacillus increased by addition of probiotics, and was higher in group H than in group N (P0 < 0.05). However, group-specific PCR-DGGE showed no obvious difference among the five groups in Lactobacillus composition and diversity. Therefore, the dietary addition of E. faecalis LAB31 can improve growth performance, reduce diarrhea, and increase the relative number of Lactobacillus in feces of weaned piglets. PMID:25617897

  11. Dietary Enterococcus faecalis LAB31 improves growth performance, reduces diarrhea, and increases fecal Lactobacillus number of weaned piglets.

    PubMed

    Hu, Yuanliang; Dun, Yaohao; Li, Shenao; Zhang, Dongxiao; Peng, Nan; Zhao, Shumiao; Liang, Yunxiang

    2015-01-01

    Lactic acid bacteria (LAB) have been shown to enhance performance of weaned piglets. However, few studies have reported the addition of LAB Enterococcus faecalis as alternatives to growth promoting antibiotics for weaned piglets. This study evaluated the effects of dietary E. faecalis LAB31 on the growth performance, diarrhea incidence, blood parameters, fecal bacterial and Lactobacillus communities in weaned piglets. A total of 360 piglets weaned at 26 ± 2 days of age were randomly allotted to 5 groups (20 pens, with 4 pens for each group) for a trial of 28 days: group N (negative control, without antibiotics or probiotics); group P (Neomycin sulfate, 100 mg/kg feed); groups L, M and H (supplemented with E. faecalis LAB31 0.5×109, 1.0×109, and 2.5×109 CFU/kg feed, respectively). Average daily gain and feed conversion efficiency were found to be higher in group H than in group N, and showed significant differences between group H and group P (P0 < 0.05). Furthermore, groups H and P had a lower diarrhea index than the other three groups (P0 < 0.05). Denaturing gradient gel electrophoresis (DGGE) showed that the application of probiotics to the diet changed the bacterial community, with a higher bacterial diversity in group M than in the other four groups. Real-time PCR revealed that the relative number of Lactobacillus increased by addition of probiotics, and was higher in group H than in group N (P0 < 0.05). However, group-specific PCR-DGGE showed no obvious difference among the five groups in Lactobacillus composition and diversity. Therefore, the dietary addition of E. faecalis LAB31 can improve growth performance, reduce diarrhea, and increase the relative number of Lactobacillus in feces of weaned piglets.

  12. Characterization of Multi-Drug Resistant Enterococcus faecalis Isolated from Cephalic Recording Chambers in Research Macaques (Macaca spp.).

    PubMed

    Woods, Stephanie E; Lieberman, Mia T; Lebreton, Francois; Trowel, Elise; de la Fuente-Núñez, César; Dzink-Fox, Joanne; Gilmore, Michael S; Fox, James G

    2017-01-01

    Nonhuman primates are commonly used for cognitive neuroscience research and often surgically implanted with cephalic recording chambers for electrophysiological recording. Aerobic bacterial cultures from 25 macaques identified 72 bacterial isolates, including 15 Enterococcus faecalis isolates. The E. faecalis isolates displayed multi-drug resistant phenotypes, with resistance to ciprofloxacin, enrofloxacin, trimethoprim-sulfamethoxazole, tetracycline, chloramphenicol, bacitracin, and erythromycin, as well as high-level aminoglycoside resistance. Multi-locus sequence typing showed that most belonged to two E. faecalis sequence types (ST): ST 4 and ST 55. The genomes of three representative isolates were sequenced to identify genes encoding antimicrobial resistances and other traits. Antimicrobial resistance genes identified included aac(6')-aph(2"), aph(3')-III, str, ant(6)-Ia, tetM, tetS, tetL, ermB, bcrABR, cat, and dfrG, and polymorphisms in parC (S80I) and gyrA (S83I) were observed. These isolates also harbored virulence factors including the cytolysin toxin genes in ST 4 isolates, as well as multiple biofilm-associated genes (esp, agg, ace, SrtA, gelE, ebpABC), hyaluronidases (hylA, hylB), and other survival genes (ElrA, tpx). Crystal violet biofilm assays confirmed that ST 4 isolates produced more biofilm than ST 55 isolates. The abundance of antimicrobial resistance and virulence factor genes in the ST 4 isolates likely relates to the loss of CRISPR-cas. This macaque colony represents a unique model for studying E. faecalis infection associated with indwelling devices, and provides an opportunity to understand the basis of persistence of this pathogen in a healthcare setting.

  13. Evaluation of Antimicrobial Effects of Different Concentrations of Triple Antibiotic Paste on Mature Biofilm of Enterococcus faecalis

    PubMed Central

    Frough Reyhani, Mohammad; Rahimi, Saeed; Fathi, Zahra; Shakouie, Sahar; Salem Milani, Amin; Soroush Barhaghi, Mohammad Hossein; Shokri, Javad

    2015-01-01

    Background and aims. Triple antibiotic paste (TAP) is widely used in endodontics for root canal disinfection, particularly in regenerative procedures. The aim of this in vitro study was to evaluate the antimicrobial effects of different concentrations of TAP at 1-, 2-, 3-, and 4-week intervals on mature Enterococcus faecalis biofilm. Materials and methods. A total of 287 extracted one-rooted human central incisors were infected with E. faecalis ATCC 29212 after removing the crown and preparation. The root canal space was filled with one of the 0.01-, 0.1-, 1-, 10-, 100-, and 1000-mg/mL concentrations of TAP or normal saline (control). The root canal dentin was sampled after 1, 2, 3, and 4 weeks. The dentinal shavings were cultured on Mueller-Hinton agar plates after serial dilutions. The classic colony-forming unit (CFU) counting technique was used to determine remaining bacterial counts. Data were analyzed by using the two-way ANOVA, post hoc Tukey tests and one-way ANOVA (P<0.05). Results. TAP completely eliminated E. faecalis biofilms at all the intervals at concentrations of 1000, 100, and 10 mg/mL, whereas 1-, 0.1-, and 0.01-mg/mL TAP resulted in significant reduction of CFU means compared with the control group. There were no statistically significant differences between the four time intervals. Conclusion. Use of lower concentrations of TAP at short term could eradicate E. faecalis biofilm and decrease high-concentration side effects. PMID:26697145

  14. A Comparison between Antibacterial Activity of Propolis and Aloe vera on Enterococcus faecalis (an In Vitro Study)

    PubMed Central

    Ehsani, Maryam; Amin Marashi, Mahmood; Zabihi, Ebrahim; Issazadeh, Maryam; Khafri, Soraya

    2013-01-01

    Removing the bacteria, including Enterococcus faecalis, from the root canal is one of the important aims in endodontic treatment.We aimed to compare the antibacterial activity of Chlorhexidine with two natural drugs. The antibacterial activities of three different propolis extracts (alcohol concentrations: 0, 15, 40%) and Aloe vera gel on E. faecalis were compared using three methods: disk diffusion, microdilution and direct contact test. In addition to the above bacterium, the Aloe vera gel effect on Staphylococcus aureus and Streptococcus mutans was evaluated. Disk diffusion test revealed that propolis ethanolic extracts (the alcohol concentration of 15 and 40%) and Aloe vera gel have antibacterial activities but aqueous extract of propolis did not show any effect in this test. The MICs for propolis ethanolic extracts, Aloe vera gel and aqueous extract of propolis (0% alcohol) were 313 µg/ml, 750 µg/ml, 2250 µg/ml, and ≥ 500 µg/ml respectively, much higher than the Chlorhexidine one. In direct contact test, contrary to Aloe vera, all three propolis extracts showed antibacterial effects on E. faecalis. The Aloe vera gel also showed significant antibacterial effect on S.aureus and S.mutans. The hydroalcoholic extracts of propolis and Aloe vera gel had antibacterial effects on E. faecalis, however, propolis is more potent than Aloe vera. The antibacterial effect of Aloe vera on S. aureus and S. mutans is low (MIC ≥ 2250 µg/ml). Appropriate concentrations of alcoholic extracts of propolis and some fractions of Aloe vera gel might be good choices for disinfecting the root canal in endodontic treatments. PMID:24551800

  15. A Comparison between Antibacterial Activity of Propolis and Aloe vera on Enterococcus faecalis (an In Vitro Study).

    PubMed

    Ehsani, Maryam; Amin Marashi, Mahmood; Zabihi, Ebrahim; Issazadeh, Maryam; Khafri, Soraya

    2013-01-01

    Removing the bacteria, including Enterococcus faecalis, from the root canal is one of the important aims in endodontic treatment.We aimed to compare the antibacterial activity of Chlorhexidine with two natural drugs. The antibacterial activities of three different propolis extracts (alcohol concentrations: 0, 15, 40%) and Aloe vera gel on E. faecalis were compared using three methods: disk diffusion, microdilution and direct contact test. In addition to the above bacterium, the Aloe vera gel effect on Staphylococcus aureus and Streptococcus mutans was evaluated. Disk diffusion test revealed that propolis ethanolic extracts (the alcohol concentration of 15 and 40%) and Aloe vera gel have antibacterial activities but aqueous extract of propolis did not show any effect in this test. The MICs for propolis ethanolic extracts, Aloe vera gel and aqueous extract of propolis (0% alcohol) were 313 µg/ml, 750 µg/ml, 2250 µg/ml, and ≥ 500 µg/ml respectively, much higher than the Chlorhexidine one. In direct contact test, contrary to Aloe vera, all three propolis extracts showed antibacterial effects on E. faecalis. The Aloe vera gel also showed significant antibacterial effect on S.aureus and S.mutans. The hydroalcoholic extracts of propolis and Aloe vera gel had antibacterial effects on E. faecalis, however, propolis is more potent than Aloe vera. The antibacterial effect of Aloe vera on S. aureus and S. mutans is low (MIC ≥ 2250 µg/ml). Appropriate concentrations of alcoholic extracts of propolis and some fractions of Aloe vera gel might be good choices for disinfecting the root canal in endodontic treatments.

  16. The in Vitro Antibacterial Efficacy of Persian Green Tea Extract as an Intracanal Irrigant on Enterococcus faecalis Biofilm

    PubMed Central

    Ramezanali, Fatemeh; Samimi, Shiva; Kharazifard, Mohammadjavad; Afkhami, Farzaneh

    2016-01-01

    Introduction: The aim of this study was to compare the antibacterial effect of Persian green tea extract (GTE) and 2.5% sodium hypochlorite (NaOCl) against Enterococcus faecalis (E. faecalis) as an intracanal irrigant. Methods and Materials: Thirty freshly extracted teeth were instrumented and sectioned into mesial and distal segments. The specimens were put into wells containing 2 mL of E. faecalis-containing medium. After 3 weeks, the specimens were removed and divided randomly into three groups (n=20). Each group was exposed to 3 mL of different irrigants for 3 min. Groups 1, 2 and 3 were irrigated with GTE, 2.5% NaOCl and normal saline, respectively. Biofilm formed in the middle third of the root canal was carved by sterile scalpel and cultured in Mueller-Hinton medium. Number of colony forming units (CFU) was counted on each plate. In addition, antimicrobial activity of the irrigants was evaluated by the agar disc diffusion test. The diameter of inhibition zone (IZ) around each irrigant was evaluated. The Kruskal-Wallis and Dunn tests were used to analysis the data. Results: While in NaOCl group no bacterial colonies were observed, the mean number of E. faecalis in GTE and control groups were 275±74 CFU/mL (P<0.001) and 119×108±11×108 (P<0.001), respectively. The mean of IZ in NaOCl and GTE groups were 24.35±0.78 and 6.9±0.87 mm, in order of appearance (P<0.001). Zone of inhibition was not observed around the control group (P<0.001). Conclusion: This research highlighted the potential role of plant extracts in antimicrobial root canal irrigation protocol. PMID:27790260

  17. Influence of the length of remaining root canal filling and post space preparation on the coronal leakage of Enterococcus faecalis

    PubMed Central

    Mozini, Alexandra Conca Alves; Vansan, Luis P.; Sousa Neto, Manoel D.; Pietro, Rosimeire

    2009-01-01

    This study evaluated the sealing ability of different lengths of remaining root canal filling and post space preparation against coronal leakage of Enterococcus faecalis. Forty-one roots of maxillary incisors were biomechanically prepared, maintaining standardized canal diameter at the middle and coronal thirds. The roots were autoclaved and all subsequent steps were undertaken in a laminar flow chamber. The canals of 33 roots were obturated with AH Plus sealer and gutta-percha. The root canal fillings were reduced to 3 predetermined lengths (n=11): G1=6 mm, G2=4 mm and G3=2 mm. The remaining roots served as positive and negative controls. Bacterial leakage test apparatuses were fabricated with the roots attached to Eppendorf tubes keeping 2 mm of apex submerged in BHI in glass flasks. The specimens received an E. faecalis inoculum of 1 x 107 cfu/mL every 3 days and were observed for bacterial leakage daily during 60 days. Data were submitted to ANOVA, Tukey’s test and Fisher’s test. At 60 days, G1 (6 mm) and G2 (4 mm) presented statistically similar results (p>0.05) (54.4% of specimens with bacterial leakage) and both groups differed significantly (p<0.01) from G3 (2 mm), which presented 100% of specimens with E. faecalis leakage. It may be concluded that the shortest endodontic obturation remnant leaked considerably more than the other lengths, although none of the tested conditions avoids coronal leakage of E. faecalis. PMID:24031339

  18. Antibacterial effect of calcium hydroxide combined with chlorhexidine on Enterococcus faecalis: a systematic review and meta-analysis

    PubMed Central

    SAATCHI, Masoud; SHOKRANEH, Ali; NAVAEI, Hooman; MARACY, Mohammad Reza; SHOJAEI, Hasan

    2014-01-01

    Objective Enterococcus faecalis (E. faecalis) is the most frequently isolated strain in failed endodontic therapy cases since it is resistant to calcium hydroxide (CH). Whether a combination of CH and chlorhexidine (CHX) is more effective than CH alone against E. faecalis is a matter of controversy. Thus, the aim of this study was to conduct a systematic review and meta-analysis of the literature. Material and Methods A comprehensive search in PubMed, EMbase, EBSCOhost, The Cochrane Library, SciELO, and BBO databases, Clinical trials registers, Open Grey, and conference proceedings from the earliest available date to February 1, 2013 was carried out and the relevant articles were identified by two independent reviewers. Backward and forward search was performed and then inclusion and exclusion criteria were applied. The included studies were divided into "comparisons" according to the depth of sampling and dressing period of each medicament. Meta-analysis was performed using Stata software 10.0. The level of significance was set at 0.05. Results Eighty-five studies were retrieved from databases and backward/forward searches. Fortyfive studies were considered as relevant (5 in vivo, 18 in vitro, 18 ex vivo, and 4 review articles). Nine studies were included for meta-analysis. Inter-observer agreement (Cohen kappa) was 0.93. The included studies were divided into 21 comparisons for meta-analysis. Chi-square test showed the comparisons were heterogeneous (p<0.001). Random effect model demonstrated no significant difference between CH/CHX mixture and CH alone in their effect on E. faecalis (p=0.115). Conclusions According to the evidence available now, mixing CH with CHX does not significantly increase the antimicrobial activity of CH against E. faecalis. It appears that mixing CH with CHX does not improve its ex vivo antibacterial property as an intracanal medicament against E. faecalis. Further in vivo studies are necessary to confirm and correlate the findings of

  19. Enterococcus faecalis strains from food, environmental, and clinical origin produce ACE-inhibitory peptides and other bioactive peptides during growth in bovine skim milk.

    PubMed

    Gútiez, Loreto; Gómez-Sala, Beatriz; Recio, Isidra; del Campo, Rosa; Cintas, Luis M; Herranz, Carmen; Hernández, Pablo E

    2013-08-16

    Enterococcus faecalis isolates from food and environmental origin were evaluated for their angiotensin-converting enzyme (ACE)-inhibitory activity (ACE-IA) after growth in bovine skim milk (BSM). Most (90% active) but not all (10% inactive) E. faecalis strains produced BSM-derived hydrolysates with high ACE-IA. Known ACE-inhibitory peptides (ACE-IP) and an antioxidant peptide were identified in the E. faecalis hydrolysates by reversed-phase high-performance liquid chromatography-tandem mass spectrometry (RP-HPLC-MS/MS). Antimicrobial activity against Pediococcus damnosus CECT4797 and Listeria ivanovii CECT913 was also observed in the E. faecalis hydrolysates. The incidence of virulence factors in the E. faecalis strains with ACE-IA and producers of ACE-IP was variable but less virulence factors were observed in the food and environmental strains than in the clinical reference strains. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) based analysis demonstrated that food and environmental E. faecalis strains were genetically different from those of clinical origin. When evaluated, most E. faecalis strains of clinical origin also originated BSM-derived hydrolysates with high ACE-IA due to the production of ACE-IP. Accordingly, the results of this work suggest that most E. faecalis strains of food, environmental and clinical origin produce BSM-derived bioactive peptides with human health connotations and potential biotechnological applications. © 2013 Elsevier B.V. All rights reserved.

  20. Comparative Analysis of Protaper and Waveone Systems to Reduce Enterococcus Faecalis from Root Canal System in Primary Molars--An in Vitro Study.

    PubMed

    Pinheiro, Sérgio Luiz; Pessoa, Carolina; da Silva, Josianne Neres; Gonçalves, Rafael Orro; Duarte, Danilo Antonio; da Silveira Bueno, Carlos Eduardo

    2016-01-01

    To assess, in vitro, the ability of the ProTaper(™) and WaveOne(™) systems to reduce Enterococcus faecalis contamination in primary molars. Sixty roots of primary molars were contaminated with E. faecalis. Roots were randomly allocated to one of four groups (n=20): ProTaper(™), WaveOne(™), control A, or control B. The files used were S1 and S2/F1 and F2 (ProTaper(™) system) and 25.08 (WaveOne(™) system). In control group A, the root canal was left uninstrumented, whereas in control group B, the root canal was irrigated with NaCl 0.9%. E. faecalis was sampled from the root canal system before and after instrumentation and the Wilcoxon test and Mann-Whitney U were used. There were no differences in E. faecalis counts between pre-instrumentation counts in the ProTaper™ and WaveOne(™) (p>0.05). The ProTaper(™) system led to an 89.36% reduction in E. faecalis burden, versus 78.10% with the WaveOne(™) system (p>0.05). Instrumentation time was shorter with WaveOne(™) (p<0.0001). The ProTaper(™) and WaveOne™ systems were equally effective in reducing Enterococcus faecalis in primary molars. The WaveOne(™) system was associated with shorter instrumentation time.

  1. Molecular characterization of resistance, virulence and clonality in vancomycin-resistant Enterococcus faecium and Enterococcus faecalis: A hospital-based study in Beijing, China.

    PubMed

    Yang, Jing-xian; Li, Tong; Ning, Yong-zhong; Shao, Dong-hua; Liu, Jing; Wang, Shu-qin; Liang, Guo-wei

    2015-07-01

    The incidence of vancomycin-resistant enterococcus (VRE) in China is increasing, the molecular epidemiology of VRE in China is only partly known. This study was conducted to assess the molecular characterization of resistance, virulence and clonality of 69 vancomycin-resistant Enterococcus faecium (VREfm) and seven vancomycin-resistant Enterococcus faecalis (VREfs) isolates obtained from a Chinese hospital between July 2011 and July 2013. The glycopeptide resistance genes (VanA and VanB) were screened by multiplex PCR. The presence of five putative virulence genes (esp, gelE, asa1, hyl and cylA) were evaluated by another multiplex PCR. Multilocus sequence typing (MLST) scheme was used to assess the clonality. All 76 VRE isolates exhibited VanA phenotype and harbored VanA gene. Esp was the only gene detected both in VREfm and VREfs strains, accounting for 89.9% and 42.9%, respectively. The hyl gene was merely positive in 27.5% of VREfm strains. MLST analysis demonstrated three STs (ST6, ST4 and ST470) in VREfs and twelve STs (ST78, ST571, ST17, ST564, ST389, ST18, ST547, ST341, ST414, ST343, ST262 and ST203) in VREfm, which were all designated as CC17 by eBURST algorithm. An outbreak of VREfm belonging to ST571 was found to happen within the neurology ward in this hospital. To our knowledge, this is the first report of ST6 (CC2) VREfs strains in China and the first outbreak report of VREfm strains belonging to ST571 around the world. Our data could offer important information for understanding the molecular features of VRE in China.

  2. The Native Plasmid pML21 Plays a Role in Stress Tolerance in Enterococcus faecalis ML21, as Analyzed by Plasmid Curing Using Plasmid Incompatibility.

    PubMed

    Zuo, Fang-Lei; Chen, Li-Li; Zeng, Zhu; Feng, Xiu-Juan; Yu, Rui; Lu, Xiao-Ming; Ma, Hui-Qin; Chen, Shang-Wu

    2016-02-01

    To investigate the role of the native plasmid pML21 in Enterococcus faecalis ML21's response to abiotic stresses, the plasmid pML21 was cured based on the principle of plasmid incompatibility and segregational instability, generating E. faecalis mutant strain ML0. The mutant and the wild strains were exposed to abiotic stresses: bile salts, low pH, H2O2, ethanol, heat, and NaCl, and their survival rate was measured. We found that curing of pML21 lead to reduced tolerance to stress in E. faecalis ML0, especially oxidative and osmotic stress. Complementation analysis suggested that the genes from pML21 played different role in stress tolerance. The result indicated that pML21 plays a role in E. faecalis ML21's response to abiotic stresses.

  3. EfaR Is a Major Regulator of Enterococcus faecalis Manganese Transporters and Influences Processes Involved in Host Colonization and Infection

    PubMed Central

    Abrantes, M. C.; Lopes, M. de F.

    2013-01-01

    Metal ions, in particular manganese, are important modulators of bacterial pathogenicity. However, little is known about the role of manganese-dependent proteins in the nosocomial pathogen Enterococcus faecalis, a major cause of bacterial endocarditis. The present study demonstrates that the DtxR/MntR family metalloregulator EfaR of E. faecalis controls the expression of several of its regulon members in a manganese-dependent way. We also show that efaR inactivation impairs the ability of E. faecalis to form biofilms, to survive inside macrophages, and to tolerate oxidative stress. Our results reveal that EfaR is an important modulator of E. faecalis virulence and link manganese homeostasis to enterococcal pathogenicity. PMID:23297382

  4. Enumeration of viable Enterococcus faecalis, a predominant apical periodontitis pathogen, using propidium monoazide and quantitative real-time polymerase chain reaction.

    PubMed

    Takahashi, Yusuke; Yoshida, Akihiro; Nagayoshi, Masato; Kitamura, Chiaki; Nishihara, Tatsuji; Awano, Shuji; Ansai, Toshihiro

    2011-12-01

    To discriminate between viable and non-viable Enterococcus faecalis, the predominant pathogen in apical periodontitis, a real-time PCR method combined with propidium monoazide (PMA) was developed and evaluated. PMA had no antimicrobial effect on E. faecalis cells and permitted enumeration of both viable and non-viable cells. Therefore, E. faecalis cells from the root canals of nine patients with apical periodontitis were analyzed to evaluate the diagnostic usefulness of this approach. Viable and non-viable E. faecalis cells were successfully discriminated in these clinical specimens. A real-time PCR assay combined with PMA will contribute to the precise diagnosis of apical periodontitis. © 2011 The Societies and Blackwell Publishing Asia Pty Ltd.

  5. Enterococcus faecalis plasmid pAD1-encoded Fst toxin affects membrane permeability and alters cellular responses to lantibiotics.

    PubMed

    Weaver, Keith E; Weaver, Dariel M; Wells, Carol L; Waters, Christopher M; Gardner, Marshall E; Ehli, Erik A

    2003-04-01

    Fst is a peptide toxin encoded by the par toxin-antitoxin stability determinant of Enterococcus faecalis plasmid pAD1. Intracellular overproduction of Fst resulted in simultaneous inhibition of all cellular macromolecular synthesis concomitant with cell growth inhibition and compromised the integrity of the cell membrane. Cells did not lyse or noticeably leak intracellular contents but had specific defects in chromosome partitioning and cell division. Extracellular addition of synthetic Fst had no effect on cell growth. Spontaneous Fst-resistant mutants had a phenotype consistent with changes in membrane composition. Interestingly, overproduction of Fst sensitized cells to the lantibiotic nisin, and Fst-resistant mutants were cross-resistant to nisin and the pAD1-encoded cytolysin.

  6. Increased pheromone cCF10 expression in Enterococcus faecalis biofilm formed by isolates from renal transplant patients.

    PubMed

    Jarzembowski, Tomasz; Daca, Agnieszka; Bryl, Ewa; Wiśniewska, Katarzyna; Gołębiewska, Justyna; Dębska-Ślizień, Alicja; Rutkowski, Bolesław; Witkowski, Jacek

    2012-12-01

    Renal transplant recipients are at a high risk of developing infectious complications even caused by commensal bacteria. This is because of various physiological non-immunological, and immunological protective mechanisms are not fully efficient in RTx patients. Therefore, rapid and precise diagnostic tools are essential in this particular group of patients. We aimed to develop simple and sensitive protocol Flow-Fish for the study of gene expression in enterococci and to compare expression of genes involved in virulence regulation in biofilm and planktonic form of Enterococcus faecalis. Proper optimization of the method was demonstrated with analysis of dehydrogenase gene expression. According to expectation reduction of the dehydrogenase gene expression was observed in biofilm. Furthermore, expression of studied gene was higher in clinical than in commensal strains. We have also found that in contrast to dehydrogenase gene, pheromone cCF10 gene expression increasing then clinical strains formed biofilm.

  7. Identification and characterization of gsp65, an organic hydroperoxide resistance (ohr) gene encoding a general stress protein in Enterococcus faecalis.

    PubMed

    Rincé, A; Giard, J C; Pichereau, V; Flahaut, S; Auffray, Y

    2001-02-01

    The Enterococcus faecalis general stress protein Gsp65 has been purified from two-dimensional gel electrophoresis. Determination of its N-terminal sequence and characterization of the corresponding gene revealed that the gsp65 product is a 133-amino-acid protein sharing homologies with organic hydroperoxide resistance (Ohr) proteins. Transcriptional analysis of gsp65 gave evidence for a monocistronic mRNA initiated 52 nucleotides upstream of the ATG start codon and for an induction in response to hydrogen peroxide, heat shock, acid pH, detergents, ethanol, sodium chloride, and tert-butylhydroperoxide (tBOOH). A gsp65 mutant showed increased sensitivity to the organic hydroperoxide tBOOH and to ethanol.

  8. Enterocin 96, a Novel Class II Bacteriocin Produced by Enterococcus faecalis WHE 96, Isolated from Munster Cheese▿

    PubMed Central

    Izquierdo, Esther; Wagner, Camille; Marchioni, Eric; Aoude-Werner, Dalal; Ennahar, Saïd

    2009-01-01

    Enterococcus faecalis WHE 96, a strain isolated from soft cheese based on its anti-Listeria activity, produced a 5,494-Da bacteriocin that was purified to homogeneity by ultrafiltration and cation-exchange and reversed-phase chromatographies. The amino acid sequence of this bacteriocin, named enterocin 96, was determined by Edman degradation, and its structural gene was sequenced, revealing a double-glycine leader peptide. After a comparison with other bacteriocins, it was shown that enterocin 96 was a new class II bacteriocin that showed very little similarity with known structures. Enterocin 96 was indeed a new bacteriocin belonging to class II bacteriocins. The activity spectrum of enterocin 96 covered a wide range of bacteria, with strong activity against most gram-positive strains but very little or no activity against gram-negative strains. PMID:19411428

  9. Enterocin 96, a novel class II bacteriocin produced by Enterococcus faecalis WHE 96, isolated from Munster cheese.

    PubMed

    Izquierdo, Esther; Wagner, Camille; Marchioni, Eric; Aoude-Werner, Dalal; Ennahar, Saïd

    2009-07-01

    Enterococcus faecalis WHE 96, a strain isolated from soft cheese based on its anti-Listeria activity, produced a 5,494-Da bacteriocin that was purified to homogeneity by ultrafiltration and cation-exchange and reversed-phase chromatographies. The amino acid sequence of this bacteriocin, named enterocin 96, was determined by Edman degradation, and its structural gene was sequenced, revealing a double-glycine leader peptide. After a comparison with other bacteriocins, it was shown that enterocin 96 was a new class II bacteriocin that showed very little similarity with known structures. Enterocin 96 was indeed a new bacteriocin belonging to class II bacteriocins. The activity spectrum of enterocin 96 covered a wide range of bacteria, with strong activity against most gram-positive strains but very little or no activity against gram-negative strains.

  10. Virulence factors in vancomycin-resistant and vancomycin- susceptible Enterococcus faecalis from Brazil

    PubMed Central

    Camargo, I. L. B. C.; Zanella, R. C.; Gilmore, M. S.; Darini, A. L. C.

    2008-01-01

    Enterococci are members of commensal flora of animals and insects, but are also important opportunistic pathogens. Our objective was to observe if there was any difference of virulence in several groups of E. faecalis, mainly between vancomycin-resistant E. faecalis (VREFS) of colonization and infection. VREFS and vancomycin-sensitive E. faecalis from Brazil were screened for the presence of virulence factor genes. Phenotypic assays were used to assess in vitro expression, to understand the pathogenic potential of these isolates and to determine whether a correlation exists between virulence and antibiotic resistance. Different virulence profiles were found suggesting that the disseminating clone may have generated several variations. However, our study showed that one constellation of traits appeared most commonly: gelatinase, aggregation substance and esp (GEA). These factors are important because they have been implicated in cell aggregation and biofilm formation. Biofilm formation may promote the conjugation of plasmids harboring resistance and virulence genes, enhancing the probability of entry of new resistance genes into species. Curiously, the profile GEA was not exclusive to VREFS, it was the second most observed in VSEFS isolates from colonization and infection in hospitalized patients and also from rectal swabs of healthy volunteers. Such strains appear to represent the entry gateway to new resistance genes into E. faecalis and may contribute to the spreading of E. faecalis mainly in hospitals. PMID:24031215

  11. The influence of different peritoneal dialysis fluids on the in vitro activity of ampicillin, daptomycin, and linezolid against Enterococcus faecalis.

    PubMed

    Kussmann, M; Schuster, L; Zeitlinger, M; Pichler, P; Reznicek, G; Wiesholzer, M; Burgmann, H; Poeppl, W

    2015-11-01

    Intraperitoneal administration of antibiotics is recommended for the treatment of peritoneal dialysis-related peritonitis. However, little data are available on a possible interference between peritoneal dialysis fluids and the activity of antimicrobial agents. Thus, the present in vitro study set out to investigate the influence of different peritoneal dialysis fluids on the antimicrobial activity of ampicillin, linezolid, and daptomycin against Enterococcus faecalis. Time-kill curves in four different peritoneal dialysis fluids were performed over 24 h with four different concentrations (1 × MIC, 4 × MIC, 8 × MIC, 30 × MIC) of each antibiotic evaluated. Cation-adjusted Mueller-Hinton broth was used as the comparator solution. All four peritoneal dialysis fluids evaluated had a bacteriostatic effect on the growth of Enterococcus faecalis. Compared to the cation-adjusted Mueller-Hinton broth comparator solution, the antimicrobial activity of all antibiotics tested was reduced. For ampicillin and linezolid, no activity was found in any peritoneal dialysis fluid, regardless of the concentration. Daptomycin demonstrated dose-dependent activity in all peritoneal dialysis fluids. Bactericidal activity was observed at the highest concentrations evaluated in Dianeal® PDG4 and Extraneal®, but not in concentrations lower than 30 × MIC and not in Nutrineal® PD4 and Physioneal® 40. The antimicrobial activity of ampicillin and linezolid is limited in peritoneal dialysis fluids in vitro. Daptomycin is highly effective in peritoneal dialysis fluids and might, thus, serve as an important treatment option in peritoneal dialysis-related peritonitis. Further studies are needed to evaluate the clinical impact of the present findings.

  12. Inactivation of Staphylococcus aureus and Enterococcus faecalis by a direct-current, cold atmospheric-pressure air plasma microjet☆

    PubMed Central

    Tian, Ye; Sun, Peng; Wu, Haiyan; Bai, Na; Wang, Ruixue; Zhu, Weidong; Zhang, Jue; Liu, Fuxiang

    2010-01-01

    Objective A direct-current, cold atmospheric-pressure air plasma microjet (PMJ) was performed to inactivate Staphylococcus aureus (S. aureus) and Enterococcus faecalis (E. faecalis) in air. The process of sterilization and morphology of bacteria was observed. We wish to know the possible inactivation mechanisms of PMJ and explore a potential application in dental and other temperature sensitive treatment. Methods In this study, we employed a direct current, atmospheric pressure, cold air PMJ to inactivate bacterias. Scanning electron microscopy was employed to evaluate the morphology of S. aureus and showed rupture of cell walls after the plasma treatment and Optical emission spectrum (OES) were used to understand the possible inactivation mechanisms of PMJ. Results The inactivation rates could reach 100% in 5 min. When the distance between the exit nozzle of the PMJ device and Petri dish was extended from 1 cm to 3 cm, effective inactivation was also observed with a similar inactivation curve. Conclusion The inactivation of bacteria is attributed to the abundant reactive oxygen and nitrogen species, as well as ultroviolet radiation in the plasma. Different life spans and defensibilities of these killing agents may hold the key to understanding the different inactivation curves at different treatment distances. PMID:23554639

  13. The Two-Component System GrvRS (EtaRS) Regulates ace Expression in Enterococcus faecalis OG1RF

    PubMed Central

    Singh, Kavindra V.; La Rosa, Sabina Leanti; Cohen, Ana Luisa V.; Murray, Barbara E.

    2014-01-01

    Expression of ace (adhesin to collagen of Enterococcus faecalis), encoding a virulence factor in endocarditis and urinary tract infection models, has been shown to increase under certain conditions, such as in the presence of serum, bile salts, urine, and collagen and at 46°C. However, the mechanism of ace/Ace regulation under different conditions is still unknown. In this study, we identified a two-component regulatory system GrvRS as the main regulator of ace expression under these stress conditions. Using Northern hybridization and β-galactosidase assays of an ace promoter-lacZ fusion, we found transcription of ace to be virtually absent in a grvR deletion mutant under the conditions that increase ace expression in wild-type OG1RF and in the complemented strain. Moreover, a grvR mutant revealed decreased collagen binding and biofilm formation as well as attenuation in a murine urinary tract infection model. Here we show that GrvR plays a major role in control of ace expression and E. faecalis virulence. PMID:25385790

  14. Inactivation of Staphylococcus aureus and Enterococcus faecalis by a direct-current, cold atmospheric-pressure air plasma microjet.

    PubMed

    Tian, Ye; Sun, Peng; Wu, Haiyan; Bai, Na; Wang, Ruixue; Zhu, Weidong; Zhang, Jue; Liu, Fuxiang

    2010-07-01

    A direct-current, cold atmospheric-pressure air plasma microjet (PMJ) was performed to inactivate Staphylococcus aureus (S. aureus) and Enterococcus faecalis (E. faecalis) in air. The process of sterilization and morphology of bacteria was observed. We wish to know the possible inactivation mechanisms of PMJ and explore a potential application in dental and other temperature sensitive treatment. In this study, we employed a direct current, atmospheric pressure, cold air PMJ to inactivate bacterias. Scanning electron microscopy was employed to evaluate the morphology of S. aureus and showed rupture of cell walls after the plasma treatment and Optical emission spectrum (OES) were used to understand the possible inactivation mechanisms of PMJ. The inactivation rates could reach 100% in 5 min. When the distance between the exit nozzle of the PMJ device and Petri dish was extended from 1 cm to 3 cm, effective inactivation was also observed with a similar inactivation curve. The inactivation of bacteria is attributed to the abundant reactive oxygen and nitrogen species, as well as ultroviolet radiation in the plasma. Different life spans and defensibilities of these killing agents may hold the key to understanding the different inactivation curves at different treatment distances.

  15. The effects of solution chemistry on the sticking efficiencies of viable Enterococcus faecalis: An atomic force microscopy and modeling study

    NASA Astrophysics Data System (ADS)

    Cail, Tracy L.; Hochella, Michael F.

    2005-06-01

    Atomic force microscopy (AFM) and Derjaguin-Landau-Verwey-Overbeek (DLVO) theory in combination with the interaction force boundary layer (IFBL) model have been used to empirically and theoretically calculate sticking efficiencies (α) of Enterococcus faecalis cells against a silica glass surface. Sticking efficiencies were calculated in solutions of varying pH and ionic strength and related to maximum distances of transport through a hypothetical soil block using colloid filtration theory. AFM measurements show that the repulsive and attractive forces between E. faecalis cells and a glass surface are a function of ionic strength but are less sensitive to changes in solution pH. Zeta (ζ)-potential measurements of the cells and glass surfaces correlate with these trends. Calculated DLVO energy profiles predict much greater sensitivity to changing solution chemistry. Sticking efficiencies derived from AFM measurements range from 9.6 × 10 -17 to 1 in solutions of low ionic strength (IS) and from 2.6 × 10 -33 to 1 at higher IS. Corresponding α values determined from DLVO theory are essentially zero in all tested solutions. Sticking efficiencies calculated in this study are smaller than values determined from column and field studies in similar systems; however, α derived from AFM data and the IFBL model more closely represent field data than do values calculated from DLVO energy values. A comparison with different methods of calculating α suggests that reversible adhesion may be significant in column-scale transport studies.

  16. Deletion of fabN in Enterococcus faecalis results in unsaturated fatty acid auxotrophy and decreased release of inflammatory cytokines.

    PubMed

    Diederich, Ann-Kristin; Duda, Katarzyna A; Romero-Saavedra, Felipe; Engel, Regina; Holst, Otto; Huebner, Johannes

    2016-05-01

    The Gram-positive bacterium Enterococcus faecalis can cause life-threatening infections and is resistant to several commonly used antibiotics. The type II fatty acid pathway in bacteria is discussed as a potential target for antimicrobial therapy. However, it was shown that inhibition or deletion of its enzymes can be rescued in Gram-positive bacteria by supplementation with fatty acids. Here we show that by deletion of the fabN gene, which is essential for unsaturated fatty acid (UFA) synthesis in E. faecalis, growth is impaired but can be rescued by supplementation with oleic acid or human serum. Nonetheless, we demonstrate alterations of the UFA profile after supplementation with oleic acid in the ΔfabN mutant using a specific glycolipid. In addition, we demonstrate that cytokine release in vitro is almost abolished after stimulation of mouse macrophages by the mutant in comparison to the wild type. The results indicate that fabN is not a suitable target for antimicrobials as UFA auxotrophy can be overcome. However, deletion of fabN resulted in a decreased inflammatory response indicating that fabN and resulting UFA synthesis are relevant for virulence.

  17. Decolorization and detoxification of sulfonated toxic diazo dye C.I. Direct Red 81 by Enterococcus faecalis YZ 66.

    PubMed

    Sahasrabudhe, Madhuri M; Saratale, Rijuta G; Saratale, Ganesh D; Pathade, Girish R

    2014-01-01

    Isolated Enterococcus faecalis YZ 66 strain shows ability to decolorize various industrial dyes among which, it showed complete decolorization and degradation of toxic, sulfonated recalcitrant diazo dye Direct Red 81 (50 mg/L) within 1.5 h of incubation under static anoxic condition. The optimum pH and temperature for decolorization was 7.0 and 40°C, respectively. Significant induction in the activity of intracellular oxidoreductive enzymes suggested its involvement in the decolorization of Direct Red 81. The biodegradation of Direct Red 81 was monitored by UV-Visible, FT-IR spectroscopy and HPLC. The final products were characterized by GC-MS and possible pathway of the degradation of the dye was proposed. The phytotoxicity assay (with respect to plants Sorghum vulgare and Phaseolus mungo) revealed that the degradation of Direct Red 81 produced nontoxic metabolites. Finally E. faecalis was employed to decolorize actual industrial effluent showing decolorization (in terms of ADMI value) with moderate COD and BOD reduction. Moreover the result increases the applicability of the strain for the treatment of industrial wastewaters containing dye pollutants.

  18. Inhibition of efflux pumps in methicillin-resistant Staphylococcus aureus and Enterococcus faecalis resistant strains by triterpenoids from Momordica balsamina.

    PubMed

    Ramalhete, Cátia; Spengler, Gabriella; Martins, Ana; Martins, Marta; Viveiros, Miguel; Mulhovo, Silva; Ferreira, Maria-José U; Amaral, Leonard

    2011-01-01

    Six cucurbitane-type triterpenoids (1-6) isolated from the aerial parts of Momordica balsamina were evaluated for their ability to inhibit the activity of bacterial efflux pumps of methicillin-resistant Staphylococcus aureus (MRSA) COL(OXA), Enterococcus faecalis ATCC 29212, Salmonella enterica subsp. I serovar Typhimurium 5408 and S. Typhimurium 5408CIP strains. The latter strain overproduces the AcrB transporter of the AcrAB-TolC efflux pump six-fold compared with its parent. Compounds 4-6 were also tested for similar activity against Escherichia coli AG100 wild-type strain and E. coli AG100TET8 that overproduces the AcrAB-TolC efflux pump. Evaluation of efflux activity was performed using a semi-automated method that measures accumulation of the universal efflux pump substrate ethidium bromide (EtBr). Some of the compounds significantly inhibited efflux of EtBr by MRSA COL(OXA) and E. faecalis ATCC 29212. A correlation between activity and the topological polar surface area of the compounds was found for MRSA COL(OXA). Copyright © 2010 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

  19. Inefficient translation renders the Enterococcus faecalis fabK enoyl-acyl carrier protein reductase phenotypically cryptic.

    PubMed

    Bi, Hongkai; Zhu, Lei; Wang, Haihong; Cronan, John E

    2014-01-01

    Enoyl-acyl carrier protein (ACP) reductase catalyzes the last step of the bacterial fatty acid elongation cycle. Enterococcus faecalis is unusual in that it encodes two unrelated enoyl-ACP reductases, FabI and FabK. We recently reported that deletion of the gene encoding FabI results in an unsaturated fatty acid (UFA) auxotroph despite the presence of fabK, a gene encoding a second fully functional enoyl-ACP reductase. By process of elimination, our prior report argued that poor expression was the reason that fabK failed to functionally replace FabI. We now report that FabK is indeed poorly expressed and that the expression defect is at the level of translation rather than transcription. We isolated four spontaneous mutants that allowed growth of the E. faecalis ΔfabI strain on fatty acid-free medium. Each mutational lesion (single base substitution or deletion) extended the fabK ribosome binding site. Inactivation of fabK blocked growth, indicating that the mutations acted only on fabK rather than a downstream gene. The mutations activated fabK translation to levels that supported fatty acid synthesis and hence cell growth. Furthermore, site-directed and random mutagenesis experiments showed that point mutations that resulted in increased complementarity to the 3' end of the 16S rRNA increased FabK translation to levels sufficient to support growth, whereas mutations that decreased complementarity blocked fabK translation.

  20. The Effect of Diode Laser on Planktonic Enterococcus faecalis in Infected Root Canals in an Ex Vivo Model.

    PubMed

    Cretella, Gilda; Lajolo, Carlo; Castagnola, Raffaella; Somma, Francesco; Inchingolo, MariaTeresa; Marigo, Luca

    2017-04-01

    This study examined the bactericidal effect of diode laser irradiation against intracanal Enterococcus faecalis. m total of 128 extracted single-rooted and single-canal teeth were treated with ProTaper instruments (Dentsply Maillefer, Ballaigues, Switzerland). A total of 120 root canals were inoculated with E. faecalis for 21 days, and the samples were randomly divided into five groups: Group 1 (n = 24) samples were irrigated with only saline solution (positive controls); Group 2 (n = 24) was treated with only 5.25% sodium hypochlorite; Group 3 (n = 24) was irrigated with saline solutions activated by diode laser; Group 4 (n = 24) was treated with 5.25% sodium hypochlorite activated by diode laser; and Group 5 (n = 24) was irrigated with saline solution with methylene blue dye activated by the diode laser Fox (Sweden & Martina, Padova, Italy); additionally, eight teeth were not contaminated and their canals were irrigated with saline solution and used as a negative control. The Uro-Quick system was used to determine the microbial residual charge. The data were analyzed using Pearson's chi-square test (p < 0.001). A statistically significant reduction in bacterial count was observed in Group 2 and Group 4 (p < 0.001). There were no statistically significant differences among the other groups (p > 0.001). Evidence indicates that the diode laser was not more effective than sodium hypochlorite in reducing free bacteria.

  1. High-throughput screening of inhibitors targeting Agr/Fsr quorum sensing in Staphylococcus aureus and Enterococcus faecalis.

    PubMed

    Desouky, Said E; Nishiguchi, Kenzo; Zendo, Takeshi; Igarashi, Yasuhiro; Williams, Paul; Sonomoto, Kenji; Nakayama, Jiro

    2013-01-01

    Staphylococcus aureus and Enterococcus faecalis employ cyclic peptide-mediated quorum sensing (QS) systems, termed agr and fsr respectively, to regulate the expression of a series of virulence genes. To identify quorum sensing inhibitors (QSIs) that target agr/fsr systems, an efficient screening system was established. In addition to the gelatinase-induction assay to examine E. faecalis fsr QS, the use of an S. aureus agr reporter strain that carries luciferase and green fluorescence protein genes under the agr P3 promoter facilitated the development of a high-throughput screen (HTS) for QSIs. As a result of screening of 906 actinomycetes culture extracts, four showed QSI activity against the agr and fsr systems without growth inhibitory activity. The extracts were purified on a small scale, and three HPLC peaks were obtained with obvious QSI activity. In sum, the established HTS system is a promising strategy for the discovery of anti-pathogenic agents targeting cyclic peptide-mediated QS in Gram-positive pathogens.

  2. Effects of Biofilm Growth on Plasmid Copy Number and Expression of Antibiotic Resistance Genes in Enterococcus faecalis

    PubMed Central

    Cook, L. C.

    2013-01-01

    Biofilm growth causes increased average plasmid copy number as well as increased copy number heterogeneity in Enterococcus faecalis cells carrying plasmid pCF10. In this study, we examined whether biofilm growth affected the copy number and expression of antibiotic resistance determinants for several plasmids with diverse replication systems. Four different E. faecalis plasmids, unrelated to pCF10, demonstrated increased copy number in biofilm cells. In biofilm cells, we also observed increased transcription of antibiotic resistance genes present on these plasmids. The increase in plasmid copy number correlated with increased plating efficiency on high concentrations of antibiotics. Single-cell analysis of strains carrying two different plasmids suggested that the increase in plasmid copy number associated with biofilm growth was restricted to a subpopulation of biofilm cells. Regrowth of harvested biofilm cells in liquid culture resulted in a rapid reduction of plasmid copy number to that observed in the planktonic state. These results suggest a possible mechanism by which biofilm growth could reduce susceptibility to antibiotics in clinical settings. PMID:23380728

  3. Protection of mice from oral Candidiasis by heat-killed enterococcus faecalis, possibly through its direct binding to Candida albicans.

    PubMed

    Ishijima, Sanae A; Hayama, Kazumi; Ninomiya, Kentaro; Iwasa, Masahiro; Yamazaki, Masatoshi; Abe, Shigeru

    2014-01-01

    To develop a new therapy against oral candidiasis, a commensal microorganism, Enterococcus faecalis was tested for its ability to modulate Candida growth in vitro and its therapeutic activities against a murine model in vivo. Addition of heat-killed E. faecalis strain EF2001 (EF2001) isolated from healthy human feces to the culture of C. albicans strain TIMM1768 inhibited adherence of the latter to a microtiter plate in a dose dependent manner and Candida cells surrounded by EF2001 were increased. To examine the protective activities of EF2001 in vivo, heat-killed EF2001 was applied orally before and after inoculation of Candida to the tongue of mice previously immunosuppressed. Two days after inoculation this inoculation, both the symptom score and CFU from swabbed-tongue were significantly reduced in the EF2001-treated animals. Histological analysis indicated that EF2001 may potentiate the accumulation of polymorphnuclear cells near a Candida-infected region. These results suggest that oral administration of EF2001 has protective activity against oral candidiasis and that the in vivo activity may be reflected by direct interaction between EF2001 and Candida cells in vitro and the potentiation of an immunostimulatory effect of EF2001.

  4. Identification of vancomycin interaction with Enterococcus faecalis within 30 min of interaction time using Raman spectroscopy.

    PubMed

    Assmann, Cora; Kirchhoff, Johanna; Beleites, Claudia; Hey, Jessica; Kostudis, Sophia; Pfister, Wolfgang; Schlattmann, Peter; Popp, Jürgen; Neugebauer, Ute

    2015-11-01

    Vancomycin is an important glycopeptide antibiotic which is used to treat serious infections caused by Gram-positive bacteria. However, during the last years, a tremendous rise in vancomycin resistances, especially among Enterococci, was reported, making fast diagnostic methods inevitable. In this contribution, we apply Raman spectroscopy to systematically characterize vancomycin-enterococci interactions over a time span of 90 min using a sensitive Enterococcus faecalis strain and two different vancomycin concentrations above the minimal inhibitory concentration (MIC). Successful action of the drug on the pathogen could be observed already after 30 min of interaction time. Characteristic spectral changes are visualized with the help of multivariate statistical analysis (linear discriminant analysis and partial least squares regressions). Those changes were employed to train a statistical model to predict vancomycin treatment based on the Raman spectra. The robustness of the model was tested using data recorded by an independent operator. Classification accuracies of >90 % were obtained for vancomycin concentrations in the lower range of a typical trough serum concentration recommended for most patients during appropriate vancomycin therapy. Characterization of drug-pathogen interactions by means of label-free spectroscopic methods, such as Raman spectroscopy, can provide the knowledge base for innovative and fast susceptibility tests which could speed up microbiological analysis as well as finding applications in novel antibiotic screenings assays. Graphical Abstract E. faecalis is incubated with vancomycin and characterized by means of Raman spectroscopy after different time points. Characteristic spectral changes reveal efficient vancomycin-enterococci-interaction.

  5. Contribution of a PerR-like regulator to the oxidative-stress response and virulence of Enterococcus faecalis.

    PubMed

    Verneuil, Nicolas; Rincé, Alain; Sanguinetti, Maurizio; Posteraro, Brunella; Fadda, Giovanni; Auffray, Yanick; Hartke, Axel; Giard, Jean-Christophe

    2005-12-01

    PerR is one of the most important transcriptional regulators involved in the oxidative-stress response in Bacillus subtilis. Here, the homologous gene in Enterococcus faecalis, ranked among the leading causes of nosocomial infection, was characterized and analysed. Phenotype analysis showed that the perR mutant was significantly more resistant to H2O2 challenge (P < 0.05). Expression of eight genes with potential roles in the oxidative-stress response was determined in the wild-type and perR-mutant strains by real-time quantitative PCR. Surprisingly, low quantitative differences in the transcriptional activity of these genes in the mutant versus wild-type were observed. Likewise, this locus was not involved in survival within murine macrophages, but in the mouse peritonitis model, the perR mutant appeared less lethal than the JH2-2 wild-type strain. The combined results show that PerR affects E. faecalis virulence and that its implication in the transcriptional regulation in this bacterium deviates from the B. subtilis model.

  6. Implication of (Mn)superoxide dismutase of Enterococcus faecalis in oxidative stress responses and survival inside macrophages.

    PubMed

    Verneuil, Nicolas; Mazé, Alain; Sanguinetti, Maurizio; Laplace, Jean-Marie; Benachour, Abdellah; Auffray, Yanick; Giard, Jean-Christophe; Hartke, Axel

    2006-09-01

    The gene encoding the manganese-containing superoxide dismutase (MnSOD) of Enterococcus faecalis was characterized. It is transcribed monocistronically from an upstream promoter identified by rapid amplification of cDNA ends (RACE)-PCR. A sodA mutant was constructed and characterized. Growth of the mutant strain was not significantly different from that of its wild-type counterpart in standing and aerated cultures. However, the mutant was more sensitive towards menadione and hydroperoxide stresses. The response to H(2)O(2) stress was analysed in more detail, and the mode of killing of this oxidant was different under anaerobic and aerobic conditions. Cultures grown and challenged under anaerobic conditions were highly sensitive to treatment with 35 mM H(2)O(2). They were largely protected by the iron chelator deferoxamine, which suggested that killing was mainly due to an enhanced Fenton reaction. In contrast, neither strain was protected by the iron chelators deferoxamine and diethylenetriaminepentaacteic acid when grown and challenged under aerobic conditions, which suggested that inactivation of the cells by H(2)O(2) was due to another killing mode. The sodA mutant was more sensitive under these conditions, showing that MnSOD is also important for protecting the cells from damage under aerobic conditions. Finally, the MnSOD of Ent. faecalis may be considered to be a virulence factor, since survival of the corresponding mutant strain was highly affected inside mouse peritoneal macrophages.

  7. Antibacterial Activity of Synthetic Peptides Derived from Lactoferricin against Escherichia coli ATCC 25922 and Enterococcus faecalis ATCC 29212

    PubMed Central

    León-Calvijo, María A.; Leal-Castro, Aur