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PubMed1989

Binding of fibronectin and albumin to Enterococcus (Streptococcus) faecalis.

Binding of human fibronectin (FN) and albumin to Enterococcus (Streptococcus) faecalis was investigated. Scatchard analysis showed that the cells could bind a maximum of 1300 molecules of FN with an association constant of 4.8 x 10(6) M-1. Binding did not appear to involve lipoteichoic acid. Heating the cells or pretreatment with protease or periodate reduced the binding, suggesting the involvement of protein and/or carbohydrate-containing components as the surface receptor. The cells could bind a maximum of 50,000 molecules of albumin but with a much lower affinity than FN (association constant 10.8 x 10(3) M-1). Surface hydrophobicity of E. faecalis was markedly decreased by albumin but not by FN.

Albumins↗
PubMed1991

Serum dependent expression of Enterococcus faecalis adhesins involved in the colonization of heart cells.

Our previous studies have shown that the adhesive ability of Enterococcus faecalis is dependent on the strain and is further modified by growth in serum. The data reported here demonstrate that E. faecalis adherence is mediated by carbohydrate residues present on the bacterial cell surface. Some of these (D-mannose and D-glucose) are expressed by strains isolated from both urinary tract infections (UTI) and endocarditis (EN) when the cells are grown in brain-heart infusion broth (BHIB), and mediate adherence to either urinary tract epithelial cells or the Girardi Heart (GH) cell line. Other residues are present only on EN strains (D-galactose and L-fucose) and mainly mediate adherence to GH cells. These ligands can also be expressed by UTI isolates after growth in serum. D-galactose-bearing adhesins also seem to be involved in internalization of serum grown UTI strains and BHIB or serum grown EN isolates into GH cells.

Bacterial Adhesion↗
PubMed2006

Multihospital surveillance of nosocomial methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococcus, and Clostridium difficile: analysis of a 4-year data-sharing project, 1999-2002.

BACKGROUND: This study sought to establish a benchmark of resistant organism rates among a cohort of regional hospitals. METHODS: The Centers for Disease Control and Prevention (CDC) definitions were used to standardize the methodology for obtaining rates per 1000 patient days of nosocomial infection and colonization with methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococcus (VRE), and nosocomial infection with Clostridium difficile (CDIF). Only newly acquired nosocomial cases were counted. Data were reported as individual hospital control charts and as cohorted aggregate data. VHA East Coast Infection Control Professionals from 32 hospitals in New Jersey and Pennsylvania were involved. RESULTS: Benchmarks were established with pooled mean rates for each cohort. During the observational period, a statistically significant downward trend was observed for VRE and MRSA (P = .02 and .0007, respectively), and an upward trend was observed for CDIF (P = .0256). CONCLUSION: Benchmarks were established to compare nosocomial MRSA, VRE, and CDIF rates. Although significant changes in rates were observed, no attempt was made to establish a causal relationship between infection control practices and observed rates. However, a secondary gain was achieved through sharing best practices.

Benchmarking↗
PubMed2006

Enterococcus faecium EK13--an enterocin a-producing strain with probiotic character and its effect in piglets.

The experiment was conducted to determine the effects of the inoculation of the probiotic and enterocin A-producing strain Enterococcus faecium EK13 on selected parameters of metabolic profile, gut microflora, growth, and health in newborn piglets of Slovak White Improved. Piglets for study were divided into two groups: one group (EK13 group, n=8) received strain EK13 per os once daily for 7 days (2ml per piglet, 10(9)CFU/mL of saline buffer). The control group of piglets (n=7) was given placebo-saline buffer. The experiment lasted 14 days. After 7 days, strain EK13 reached 9.8 log(10) CFU/g in faeces of E. faecium EK13 treated piglets while counts of Escherichia coli were significantly lower (P<0.01) than in piglets of the control group. The concentrations of total serum protein, calcium, haemoglobin, haematocrit, red blood cell count and index of phagocytic activity of leukocytes were significantly higher after application of strain EK13. On the other hand, cholesterol was significantly lower in the EK13 group of animals. On day 14, piglets were killed and samples of intestinal contents were taken. Total counts of bacteria in the intestinal contents (jejunum, ileum, caecum, colon) were not significantly influenced. The pH value was significantly lower (P<0.05) only in duodenum of piglets receiving E. faecium EK13. There was a significant higher concentration of lactic acid (P<0.01) and propionic acid in the colon (P<0.001) of the EK13 group. Application of E. faecium EK13 did not influence the daily body weight gain significantly.

Animals↗
PubMed2004

Quantitative real-time PCR detection of oral Enterococcus faecalis in humans.

OBJECTIVE: Enterococcus faecalis is consistently associated with recurrent root canal infections. Only low concentrations of E. faecalis in the human mouth have been demonstrated by culture techniques. Quantitative detection strategies more sensitive than culturing, such as quantitative PCR (qPCR), could provide more illuminating data. DESIGN: Thirty outpatients attending the University of Michigan Graduate Endodontic Clinic for endodontic treatment provided oral rinse samples that were analysed for E. faecalis using qPCR and microbiological culturing. A SYBR Green I qPCR protocol was developed for the quantifiable detection of E. faecalis and total bacteria in oral rinse samples using primers designed to target the 16S rRNA gene. Annealing temperature and primer, magnesium ion, and dimethyl sulfoxide concentrations were investigated for optimisation of the protocol; a minimum sensitivity limit of 23 rRNA copies (an estimated six E. faecalis cells) was established for E. faecalis in pure culture, and 104 rRNA copies (an estimated 26 E. faecalis cells) in mixed culture. RESULTS: In qPCR assays, based on extrapolation from estimated rRNA gene copy numbers, E. faecalis comprised 0.0006-0.0047% of a total bacteria load that ranged from 5.92 x 10(5) to 5.69 x 10(7) cells/ml of oral rinse. E. faecalis was detected in five (17%) samples in concentrations from 114 to 490 cells/ml. In parallel culture assays E. faecalis were detected in only two samples (7%) of the five identified by qPCR and in concentrations 30 and 240 CFU/ml. CONCLUSIONS: qPCR reported a higher incidence of E. faecalis in oral rinse samples than culture techniques and afforded greater sensitivity.

Colony-Forming Units Assay↗
PubMed2004

Bacteriocin of Enterococcus from lactoserum able to cause oxidative stress in Staphylococcus aureus.

The effect of a bacteriocin of Enterococcus on the oxidative metabolism of sensitive bacteria was investigated through the detection of oxidative stress by chemiluminescence (CL). The bacteriocin named EntB was purified to study the action on Staphylococcus aureus isolated from cosmetic. Chromatographic separation of EntB indicated different states of oligomerization with molecular weights multiple of 12,000Da monomeric form. The monomer purified by ion exchange was studied in its capacity to affect the oxidative metabolism of S. aureus, which showed increase of anion superoxide (O(2)(-)) when incubated with EntB. This effect was compared to the action of EntB on leukocytes as an assay of toxicity. EntB did not generate significant oxidative stress in leukocytes. Pyoverdin, a leukotoxic pigment of Pseudomonas fluorescens, was taken as reference, and it was found that this pigment caused similar oxidative stress to EntB in S. aureus; however, pyoverdin generated high production of anion superoxide (O(2)(-)) in leukocytes, while EntB did not increase the level of O(2)(-).

Bacteriocins↗
PubMed2006

New bisanthraquinone antibiotics and semi-synthetic derivatives with potent activity against clinical Staphylococcus aureus and Enterococcus faecium isolates.

The escalation of antibiotic resistance among Gram-positive pathogens presents increasing treatment challenges and requires the development of innovative therapeutic agents. Here, we present the antimicrobial properties of structurally unusual bisanthraquinone metabolites produced by a marine streptomycete and four semi-synthetic derivatives. Biological activities were measured against clinically derived isolates of vancomycin-resistant Enterococcus faecium (VRE), and methicillin-susceptible, methicillin-resistant, and tetracycline-resistant Staphylococcus aureus (MSSA, MRSA, and TRSA, respectively). The most potent antibiotic displayed MIC(50) values of 0.11, 0.23, and 0.90microM against a panel (n=25 each) of clinical MSSA, MRSA, and VRE, respectively, and was determined to be bactericidal by time-kill analysis.

Anthraquinones↗
PubMed2006

High frequency of vancomycin-resistant Enterococcus faecium isolates with VanB phenotype and vanA genotype in Korean hospitals.

A total of 59 vancomycin-resistant Enterococcus faecium (VREF) clinical isolates were collected from 8 Korean hospitals for 2 months in 2004. They were investigated by genotyping for glycopeptide resistance, multilocus sequence typing (MLST), esp repeat profiling, and structural analysis of Tn1546-like element. Nine of 59 VREF isolates (15.3%) from 5 hospitals in Korea showed VanB phenotype, but they contained vanA gene. MLST and esp repeat profiling indicated that E. faecium isolates with VanB phenotype and vanA genotype occurred from independent genetic background except 3 isolates from 1 hospital. Structural analysis of Tn1546 also showed that these isolates were not clonally related. Data showed a relatively high frequency of VREF isolates with incongruence between phenotype and genotype for glycopeptide resistance in Korean hospitals.

Bacterial Proteins↗
PubMed2004

Toxicity evaluation for an Enterococcus faecium strain TM39 in vitro and in vivo.

Previously, we have screened lactic acid bacteria (LAB) strains from infant feces and evaluated their functional properties. We found a strain of Enterococcus faecium termed as TM39 which is acid and bile tolerant, able to adhere to the intestinal epithelium and with antagonistic activity against Helicobacter pylori. In this study, we demonstrate that strain TM39 is not vancomycin resistant, not invasive to human gastric carcinoma cell line TSGH 9201 and human intestinal epithelial cell line Int-407 in vitro. In addition, we have conducted the in vivo study to evaluate the toxicity of this E. faecium strain TM39 in Wistar rats. For such study, cells of strain TM39 were daily oral administrated with dose of 1 x 10(12), 5 x 10(11) and 2 x 10(10) CFU/kg of body weight, respectively, to the rats for 28 consecutive days. There were no adverse effects on the general condition, behavior, growth, feed and water consumption, hematology, clinical chemistry values, organ weights and histopathologic analysis of the rats. Results of this study demonstrate that consumption of strain E. faecium TM39, even in large quantities, is not associated with any obvious signs of toxicity in Wistar rats.

Animals↗
PubMed2004

Conjugal transfer of aminoglycoside and macrolide resistance between Enterococcus faecium isolates in the intestine of streptomycin-treated mice.

The purpose was to study conjugal transfer of resistance genes between a multi-resistant Enterococcus faecium isolate and a sensitive E. faecium isolate. Co-transfer of erm(B)-Tn5405-like element and aac(6')-Ie-aph(2'')-Ia was obtained in both in vivo and in vitro. Plasmid profiles and Southern blots showed that both the erm(B)-Tn5405-like element and aac(6')-Ie-aph(2'')-Ia were placed on the same large plasmid (>147 kb). These data show to our knowledge the first co-transfer of the erm(B)-Tn5405-like element and aac(6')-Ie-aph(2'')-Ia. The in vivo study also indicates that transfer of resistance genes between enterococci might occur under natural conditions in the gut of animals.

Aminoglycosides↗
PubMed2004

The cme gene of Clostridium difficile confers multidrug resistance in Enterococcus faecalis.

Antibiotic resistance in C. difficile by efflux has been previously suggested. The genome of C. difficile 630 was screened for sequences encoding putative proteins homologous to NorA from Staphylococcus aureus. Four ORFs homologous to efflux genes were cloned into the pAT79 shuttle vector under the control of transcription and translation signals of Gram-positive bacteria and expressed in Enterococcus faecalis JH2-2 and S. aureus RN4220. One of these sequences, designated cme conferred resistance to ethidium bromide, safranin O, and erythromycin in E. faecalis. The three other ORFs did not confer detectable resistance in both bacteria.

Amino Acid Sequence↗
PubMed2004

Galangin expresses bactericidal activity against multiple-resistant bacteria: MRSA, Enterococcus spp. and Pseudomonas aeruginosa.

The antimicrobial activity of three propolis ethanol extracts (EEP) was examined for various Gram-negative and Gram-positive bacterial species, including multiple-resistant Staphylococcus aureus, Enterococcus spp. and Pseudomonas aeruginosa strains. EEP had a good bactericidal activity against Gram-positive species, and all multiple-resistant bacterial strains tested were sensitive to EEP. Minimal inhibitory concentrations (MICs) were lower in samples of higher flavonoid content (from 0.65 to 7.81 mg mL(-1)), indicating the influence of the concentration of some potent bactericidal compound(s) in propolis or synergism among some bactericidal compounds. Antimicrobial-guided separation of flavonoid aglycones (bioassay in situ on thin-layer chromatogram) showed that galangin (3,5,7-trihydroxyflavone) is one compound in EEP with bactericidal activity. Galangin was isolated by preparative chromatography. After determining the quantity present, the MIC against multiple-resistant bacteria was determined. The MIC of galangin against multiple-resistant bacterial strains was significantly lower (from 0.16 to 0.44 mg mL(-1), p < 0.05) than that of EEP. The bactericidal activity of galangin against P. aeruginosa strains was present at 0.17+/-0.05 mg mL(-1).

Anti-Bacterial Agents↗
PubMed2005

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

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.

Animals↗
PubMed2005

Characterization of transferable tetracycline resistance genes in Enterococcus faecalis isolated from raw food.

The prevalence of tetracycline resistance, and of specific genetic determinants for this resistance was investigated in 1003 strains of Enterococcus faecalis isolated from various raw food products originating from five categories including chicken meat, other poultry meat, beef, pork, and 'other'. For the 238 resistant isolates identified, the ability to transfer the resistant phenotype to a given recipient in vitro was investigated. New and interesting observations were that the tet(L) resistance determinant was more readily transferred than tet(M), and that the presence of Tn916-like elements known to encode tet(M) did not correlate with increased transferability of the resistant phenotype.

Animals↗
PubMed2005

Drug resistance of Enterococcus faecium clinical isolates and the conjugative transfer of gentamicin and erythromycin resistance traits.

Drug resistance and the transferability of resistance were examined in 218 Enterococcus faecium clinical isolates obtained from in-patients of a Japanese university hospital between 1990 and 1999. One hundred and sixty one isolates (73.9%) were drug-resistant and 127 (58.2%) isolates were resistant to two or more drugs. Vancomycin resistant E. faecium (VRE) was not isolated. The transferability of drug-resistance to an E. faecium strain was examined by broth or filter mating. Six (12.5%) of the 48 gentamicin resistance traits, and fifty (50%) of the 101 erythromycin resistance traits were transferred by filter mating. The gentamicin resistance traits of five isolates and the erythromycin resistance traits of four isolates were transferred to the recipient strains by both broth mating and filter mating at a frequency of about 10(-6) and 10(-5) per donor cell, respectively. The five gentamicin resistant strains were shown to harbor pMG1-like plasmids on the basis of their Southern hybridization with pMG1 (65.1 kbp, Gm(r)), which transfers efficiently between enterococci by broth mating. Each of the four erythromycin resistant transconjugants obtained by broth mating harbored a large conjugative plasmid (more than 100 kbp). The plasmids showed no homology with well-characterized enterococcal conjugative plasmids such as pAD1, pPD1, pAM(beta)1, pIP501 and pMG1 by Southern hybridization. Of the erythromycin resistance traits that transferred only by filter mating, it was found that the erythromycin resistance trait was conferred by a 47-kbp transposable element that transferred from the chromosome of the donor strain to different sites within the pheromone responsive plasmid pAD1 (60 kbp) of the recipient strain, suggesting that the erythromycin resistance trait was encoded on a conjugative transposon, which was named Tn950.

Anti-Bacterial Agents↗
PubMed2005

Heterologous extracellular production of enterocin P from Enterococcus faecium P13 in the methylotrophic bacterium Methylobacterium extorquens.

Enterocin P (EntP), a strong antilisterial pediocin-like bacteriocin from Enterococcus faecium P13, was produced by Methylobacterium extorquens. For heterologous expression of EntP in the methylotrophic bacterium M. extorquens, a recombinant plasmid was constructed. The gene encoding the EntP structural gene (entP) was cloned into the plasmid vector pCM80, under control of the methanol dehydrogenase promoter (P(mxaF)), to generate plasmid pS25. When M. extorquens ATCC 55366 was transformed with pS25, EntP was detected and quantified in supernatants of the recombinant M. extorquens S25 strain by using specific anti-EntP antibodies and a non-competitive indirect enzyme-linked immunosorbent assay (NCI-ELISA). Purification of EntP by hydrophobic adsorption and reverse-phase (RP-FPLC) chromatographies, permitted recovery of active EntP from the supernatants of M. extorquens S25 grown in a synthetic defined medium.

Bacteriocins↗
PubMed2005

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

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.

Animals↗
PubMed2004

Synergistic activity of vancomycin and teicoplanin alone and in combination with streptomycin against Enterococcus faecalis strains with various vancomycin susceptibilities.

The synergy between two glycopeptides, vancomycin (Vm) and teicoplanin (Tec) and streptomycin (Sm) was studied by time-kill method. Five clinical vanB resistant Enterococcus faecalis (ENC) isolates with variable Vm-susceptibility were used. Different concentrations of Vm, Tec and Sm representing therapeutic concentrations were combined. Antibacterial activity was related to the concentrations of Vm and Sm, and Vm susceptibility to ENC. For strains with Vm MIC up to 64 mg/l, synergy was achieved with higher concentrations of Vm and Sm, while all combinations of Tec and Sm were synergistic against all strains except ENC 29. For ENC 29 with Vm MIC of 512 mg/l and Tec MIC of <1 mg/l, none of the combinations was synergistic. The significance of these in vitro results needs further investigation in vivo.

Anti-Bacterial Agents↗