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PubMed2001

Effect of pheromone induction on transfer of the Enterococcus faecalis plasmid pCF10 in intestinal mucus ex vivo.

The effect of synthetic sex pheromone on pheromone-inducible conjugation between the isogenic Enterococcus faecalis strains OG1RF and OG1SS was investigated in (i) Todd-Hewitt broth medium and (ii) intestinal mucus isolated from germ-free rats. In broth, the presence of synthetic pheromone cCF10 had no detectable effect on the transfer kinetics observed for the tetracycline resistance encoding plasmid pCF10. In mucus, presence of the same pheromone significantly increased the transfer efficiency observed during the first 2 h of conjugation, while the effect was less pronounced later in the experiment. We suggest that due to differences in diffusion rates and medium-binding of the pheromones, the effect of the synthetic cCF10 was immediately dominated by the effect of pheromones produced by the recipient E. faecalis strain in broth, while this happened later in mucus.

Cecum↗
PubMed2002

Characterization of genes homologous to the general stress-inducible gene gls24 in Enterococcus faecalis and Lactococcus lactis.

Three genes (Ef0604, ymgG, and ytgH) were identified as homologous to the gls24 gene (encoding the general stress protein Gls24) in Enterococcus faecalis V583 and Lactococcus lactis IL1403 genomes sequences, and therefore are part of the 'gls24 family'. The other proteins encoded by the different surrounding genes in each of their respective operons are also highly similar. Our transcriptional analysis showed that Ef0604 and ymgG are not induced under the stress conditions tested. On the other hand, ytgH is induced at the onset of glucose starvation and by heat, ethanolic, osmotic, and CdCl(2) stresses. The transcriptional start site of this operon was identified and the promoter region appears to contain an 'extended -10 Box'. Moreover, the over-expression under several stress conditions of the YtgH protein observed on 2D gel electrophoresis confirms that it corresponds to a general stress protein in L. lactis.

Bacterial Proteins↗
PubMed2002

Influence of growth media on vancomycin resistance of Enterococcus isolates and correlation with resistance gene determinants.

The effect of Mueller-Hinton (MH), MH+blood or brain heart infusion medium (agar or broth) on 13 Enterococcus isolates was determined, when testing their antibiotic susceptibility. Disk diffusion and Vitek methods were used to determine vancomycin resistance, while broth dilution and E-test methods were used to measure the minimum inhibitory concentration. The data were correlated with the presence of vancomycin resistance genes. A definite correlation pattern could not be established between the presence of van genes and vancomycin resistance in any plating medium, when tested by the disk diffusion assay. The broth dilution, irrespective of the plating medium, and Vitek methods were more reliable than the E-test method in testing isolates with vanA or vanB genes. However, for vanC2/C3 genotypes, the E-test method, irrespective of the plating medium, tested better than the broth dilution assay.

Culture Media↗
PubMed2002

A variant enterococcal surface protein Esp(fm) in Enterococcus faecium; distribution among food, commensal, medical, and environmental isolates.

Enterococci are increasingly important causes of nosocomial disease. Also, they are associated with food and have a history of use as dairy starter and probiotic cultures. An enterococcal surface protein Esp(fs) is involved the virulence and biofilm-forming capacity of Enterococcus faecalis and recently we demonstrated the presence of a homologue Esp(fm) in E. faecium. Here we describe the complete structure of Esp(fm) and demonstrate that its distribution in E. faecium correlates with disease associated strains from a range of pathological sites.

Amino Acid Sequence↗
PubMedDate not supplied

Role of penicillin-binding protein 5 C-terminal amino acid substitutions in conferring ampicillin resistance in Norwegian clinical strains of Enterococcus faecium.

The importance of amino acid sequence differences in the C-terminal part and levels of mRNA expression of penicillin-binding protein 5 (PBP5) for ampicillin resistance in Enterococcus faecium was investigated. Seventeen isolates from Norwegian hospitalized patients (ampicillin MIC 0.064->256 mg/L) with different C-terminal pbp5 DNA sequences encoding 11 different amino acid sequences were analyzed with a 14C-radiolabeled penicillin- binding assay to PBP5 and with real-time PCR quantification of pbp5 mRNA expression. Using multiple logistic regression analysis the amino acid substitution Met 485 was linked to ampicillin MIC and levels of 14C-radiolabeled penicillin bound to PBP5; however, there were isolates with identical PBP5 alleles and different ampicillin MICs. There was no relation between the quantity of pbp5 mRNA transcripts and ampicillin resistance. The results cannot explain ampicillin resistance in Norwegian clinical strains of E. faecium and indicate that other factors besides the properties of the C-terminal part of PBP5 are most likely involved.

Amino Acid Substitution↗
PubMed2004

Lipoteichoic acid derived from Enterococcus faecalis modulates the functional characteristics of both normal peripheral blood leukocytes and native human acute myelogenous leukemia blasts.

OBJECTIVES: Several case reports have described complete hematological remissions for patients with otherwise untreated acute myelogenous leukemia (AML) who receive hematopoietic growth factor therapy during complicating bacterial infections. This may be caused by indirect cytokine effects, but direct effects of infecting agents on the malignant cells are also possible because bacterial molecules can bind to specific receptors expressed by normal and malignant leukocytes. Lipoteichoic acid (LTA) is a cell wall component of gram-positive bacteria, and it can activate normal immunocompetent cells through binding to specific cell membrane receptors. METHODS: We investigated effects of LTA derived from Enterococcus faecalis on in vitro cultured (i) normal peripheral blood mononuclear cells (PBMC); (ii) remaining T cells derived from patients with hematologic malignancies and chemotherapy-induced leukopenia; and (iii) native human AML cells. RESULTS: Increased interleukin 1beta (IL1beta) and IL8 release by in vitro cultured normal PBMC was observed after stimulation with LTA at concentrations > or =5 microg/mL; these levels were lower than for lipopolysaccharide (LPS)-stimulated cells and LTA antagonized LPS-induced cytokine release by normal PBMC. In most cases LTA did not alter T-cell proliferation for patients with chemotherapy-induced leukopenia. The LTA effects on AML blasts were investigated for 62 consecutive patients. LTA altered either cytokine (granulocyte-macrophage colony-stimulating factor + stem cell factor + IL3)-dependent proliferation or the release of IL1beta/IL8 for 23 patients; the effects were divergent but increased proliferation/cytokine levels were most commonly observed. CONCLUSION: The LTA derived from E. faecalis can modulate the functional characteristics of normal leukocytes and native human AML blasts.

Adult↗
PubMed2004

In vitro antibacterial effect of calcium hydroxide combined with chlorhexidine or iodine potassium iodide on Enterococcus faecalis.

Several studies have shown a higher success rate of root canal therapy when the canal is free from bacteria at the time of obturation. Treatment strategies that are designed to eliminate this microflora should include agents that can effectively disinfect the root canal. Enterococcus faecalis is often associated with persistent endodontic infections. While in vivo studies have indicated calcium hydroxide to be the most effective all-purpose intracanal medicament, iodine potassium iodide (IKI) and chlorhexidine (CHX) may be able to kill calcium hydroxide-resistant bacteria. Supplementing the antibacterial activity of calcium hydroxide with IPI or CHX preparations was studied in bovine dentine blocks. While calcium hydroxide was unable to kill E. faecalis in the dentine, calcium hydroxide combined with IKI or CHX effectively disinfected the dentine. The addition of CHX or IKI did not affect the alkalinity of the calcium hydroxide suspensions. It may be assumed that combinations also have the potential to be used as long-term medication. Cytotoxicity tests using the neutral red method indicated that the combinations were no more toxic than their pure components.

Animals↗
PubMed2006

Functional characterization and Me ion specificity of a Ca-citrate transporter from Enterococcus faecalis.

Secondary transporters of the bacterial CitMHS family transport citrate in complex with a metal ion. Different members of the family are specific for the metal ion in the complex and have been shown to transport Mg(2+)-citrate, Ca(2+)-citrate or Fe(3+)-citrate. The Fe(3+)-citrate transporter of Streptococcus mutans clusters on the phylogenetic tree on a separate branch with a group of transporters found in the phylum Firmicutes which are believed to be involved in anaerobic citrate degradation. We have cloned and characterized the transporter from Enterococcus faecalis EfCitH in this cluster. The gene was functionally expressed in Escherichia coli and studied using right-side-out membrane vesicles. The transporter catalyzes proton-motive-force-driven uptake of the Ca(2+)-citrate complex with an affinity constant of 3.5 microm. Homologous exchange is catalyzed with a higher efficiency than efflux down a concentration gradient. Analysis of the metal ion specificity of EfCitH activity in right-side-out membrane vesicles revealed a specificity that was highly similar to that of the Bacillus subtilis Ca(2+)-citrate transporter in the same family. In spite of the high sequence identity with the S. mutans Fe(3+)-citrate transporter, no transport activity with Fe(3+) (or Fe(2+)) could be detected. The transporter of E. faecalis catalyzes translocation of citrate in complex with Ca(2+), Sr(2+), Mn(2+), Cd(2+) and Pb(2+) and not with Mg(2+), Zn(2+), Ni(2+) and Co(2+). The specificity appears to correlate with the size of the metal ion in the complex.

Bacterial Proteins↗
PubMed2006

Fusion of fungicidal peptide dhvar4 to enterococcal peptide pheromone increases its bactericidal activity against Enterococcus faecalis.

Bacterial peptide pheromone has a high affinity to its membrane receptor. Fusion of these peptides to pore-forming antimicrobial peptide might enhance its bactericidal activity against pheromone-sensing bacteria. We constructed two chimeric peptides by fusing the pore-forming fungicidal peptide dhvar4 to the C-terminus of enterococcal peptide pheromones cCF10 and cOB1 individually. Comparison on the bactericidal activities against pheromone-sensing bacteria Enterococcus faecalis demonstrates that the chimeric peptides cCF10-dhvar4 and cOB1-dhvar4 are more potent than the parent peptide dhvar4. The LD(50)s of both chimeric peptides (1.0 microm) are 10 times lower than that of dhvar4 (10.8 microm). Free peptide pheromone could inhibit E. faecalis killing mediated by both chimeric peptides. As same as that of the parent peptide, both chimeric peptides kill bacteria by disrupting its cell membrane. These results indicate that fused enterococcal peptide pheromone increases the bactericidal activity of fungicidal peptide against E. faecalis by improving its ability to reach the cell membrane.

Anti-Bacterial Agents↗
PubMed1991

The fluoroquinolones exert a reduced rate of kill against Enterococcus faecalis.

The bactericidal activities of ciprofloxacin, ofloxacin and DR-3355 have been investigated against Enterococcus faecalis, Staphylococcus aureus and Staphylococcus epidermidis over 24 h. The three fluoroquinolones were found to be rapidly bactericidal against the staphylococci, killing over 99% of the bacteria during the first 3 h of exposure with a further reduction in viability of approximately one logarithm occurring over the next 21 h. In contrast, the fluoroquinolones displayed a much slower rate of kill against E. faecalis, as little or no bactericidal activity was detected over the first 3 h for both E. faecalis ATCC19433 and a clinical isolate. At 6 h all three of the drugs were bactericidal against the enterococci although the amount of kill was not as great as against the staphylococci. However, at 24 h the amount of kill obtained with all three drugs was similar to that obtained for staphylococci exposed to these drugs. Ciprofloxacin, ofloxacin and DR-3355 were not active against E. faecalis ATCC19433 in phosphate buffered saline and therefore require cell division for their bactericidal activity against this species.

Anti-Infective Agents↗
PubMed2025

Cellodextrin Metabolism and Phosphotransferase System-Catalyzed Uptake in Enterococcus faecalis.

Two PTS transporters involved in the uptake of cellobiose and short cellooligosaccharides were identified in Enterococcus faecalis. Genes coding for the different EII proteins are found in a locus composed of three operonic structures expressing two distinct EIIC (CelC1 and CelC2), two identical EIIB (CelB1 and CelB2) and a unique EIIA (CelA1). The EIIA plays a central role in β-glucoside uptake because it is required not only for β-homodiholosides but also for the diheteroside N-acetylglucosamine-L-asparagine. Depending on their size, cellooligosaccharides are preferably transported either by CelC1 (di-saccharides) or by CelC2 (4 glycosidic residues and more), with tri-saccharides being taken up by both EIIC transporters. Moreover, CelA1B2C2 require CelGHI to be functional, three small proteins, the function of which remains unknown. CelA1B1C1 is the main but not exclusive transporter of cellobiose and chitobiose. It is involved in the transport of other β-glucodisaccharides, such as laminaribiose and sophorose. This PTS can be complemented by other transporters highlighting the existence of a network for β-glucoside uptake. This locus is under the control of CelR, a LevR-like transcription activator.

Enterococcus faecalis↗
PubMed1990

[The virulence of Enterococcus faecalis in experimental urinary tract infection in mice].

The virulence of Enterococcus faecalis in the urinary tract in mice was studied. Pyelonephritis was distinctly caused by E. faecalis which have a high affinity to mouse kidneys. This infection was continuous, but did not turn into sepsis. The relationship between the production of hemolysin or protease and the virulence in the urinary tract was investigated without finding any distinct association. It is concluded that E. faecalis is a pathogenic organism in the urinary tract and presumably induces a severe infection in the compromised host.

Animals↗
PubMed1991

[The infectivity of Enterococcus faecalis in experimental urinary tract infection in mice: II].

The infectivity of Enterococcus faecalis was compared with that of Escherichia coli in the urinary tract in mice. The infectivity of E. faecalis in normal mice was found to be equal to that of E. coli. The mice previously treated with cyclophosphamide, carrageenin or alloxan as the immunosuppressive drug, and restricted water supply, were more susceptible to enterococcal infection than non-treated ones. These data were confirmed with histological examinations. E. faecalis is a pathogenic organism in the urinary tract and therefore cautions should be given to the treatment in clinical practice.

Animals↗
PubMed1994

[Enterococcus faecium obtained from surveillance cultures of the stool of the patients with hematological malignancies].

Surveillance cultures of the stool were obtained from 55 patients with hematological malignancies, who have been receiving norfloxacin or tosufloxacin during their neutropenic periods, from May, 1991 to September, 1992. Cultures were performed using 5% blood agar with piperacillin 300 micrograms/ml and amikacin 20 micrograms/ml and bacteria resistant to these antibiotics were analyzed further. Thirty-four over 55 patients were positive for enterococci and 22 strains of 23 examined were Enterococcus faecium. They are resistant to quinolones, aminoglycosides, cephalosporins and penicillins but not to vancomycin. Eighteen of them were also resistant to high-dose gentamicin. Appropriate measures should be used to prevent intrahospital spread of these resistant isolates.

4-Quinolones↗
PubMed1994

[Fundamental and clinical studies on MIC breakpoint of SY5555 for Enterococcus faecalis in complicated urinary tract infections of moderate severity].

A multicenter clinical study was carried out to investigate the clinical efficacy of SY5555 from viewpoint of its MIC breakpoint for Enterococcus faecalis. SY5555 was administered in dosages of 150 mg x 3/day and 300 mg x 3/day, for 7 days, to patients with complicated urinary tract infections of moderate severity (no indwelling catheter). Based primarily on the bacteriological efficacy (eradication) as the criterion for evaluation, the MIC breakpoint of SY5555 was investigated. SY5555 showed potent antimicrobial activity towards E. faecalis, and its MIC80 value for the clinical isolates of this bacterial species was 1.56 micrograms/ml. Analysis was carried out to determine the extent to which this in vitro activity is corroborated by the drug's clinical efficacy in eradicating E. faecalis. 1. Experimental study In a study employing an experimental model of complicated bladder infections of moderate severity, it was judged that the MIC breakpoints of SY5555 administered at 150 mg x 3/day and 300 mg x 3/day were 2 micrograms/ml and 8 micrograms/ml. 2. Clinical study SY5555 was administered at 150 mg x 3/day (7 days) to six patients and at 300 mg x 3/day (7 days) to 32 patients, and the clinical efficacy of these treatments was investigated. 2.1. Investigation of the clinical MIC breakpoint showed it to be 12.5 micrograms/ml for both the 150 mg x 3/day and 300 mg x 3/day regimens. However, since the number of cases in this study was small, analysis was performed of the data from a large number of cases by including the cases registered in a nation-wide Phase II study of SY5555. That analysis showed the clinical MIC breakpoint for the two dosages to be 3.13 micrograms/ml and 6.25 micrograms/ml. Thus, this analysis of large number of cases yielded clinical MIC breakpoint that are in agreement with the abovementioned experimental MIC breakpoints. 2.2. In the evaluation of the efficacy rate using the UTI drug efficacy evaluation criteria, cases rated as "good" or "excellent" numbered five of the six patients in the 150 mg x 3/day treatment group and 25 of the 32 (78.1%) patients in the 300 mg x 3/day treatment group, or 30/33 (78.9%) cases overall. These efficacy rates are about the same as the 82.0% reported for the nation-wide Phase II study. 2.3. Each of the strains of E. faecalis isolated from the patients was found to be eradicated by the SY5555 treatment: four strains in the 150 mg dosage group (the MIC of each was 3.13 micrograms/ml or less) and 18 strains in the 300 mg dosage group (the MIC of each was 6.25 micrograms/ml or less). Moreover, in both dosage groups, E. faecalis was not found to recur after the SY5555 treatment. 3. Conclusions In consideration of the above findings in the investigations of treatment of patients with complicated urinary tract infections of moderate severity, the following conclusions can be drawn. 3.1. In antimicrobial treatment employing SY5555 in a regimen consisting of 300 mg x 3/day for 7 days, the clinical breakpoint is in the range of 6.25-12.5 micrograms/ml. 3.2. In particular, as would be surmised from the fact that the MIC80 value of SY5555 for E. faecalis isolated is 1.56 micrograms/ml, this drug shows quite strong efficacy in the eradication of E. faecalis from cases of complicated urinary tract infection.

Adult↗
PubMed1998

[Therapeutic effect of cefluprenam on polymicrobial urinary tract infection associated with Enterococcus faecalis, using the infectious urolithiasis model in rats].

We examined the therapeutic effect of cefluprenam (CFLP) on the polymicrobial urinary tract infection associated with infectious stones as compared to that of ceftazidime (CAZ), using the experimental polymicrobial urinary tract infection caused by Proteus mirabilis (P. mirabilis), Pseudomonas aeruginosa (P. aeruginosa) and Enterococcus faecalis (E. faecalis). In order to form bladder stones in rats, a sterile zinc ring was implanted as a foreign body, followed by inoculating P. mirabilis E05106 transurethrelly. Thereafter, P. aeruginosa E030033 and E. faecalis 966 were inoculated according to the same way. CFLP or CAZ was administered intravenously twice a day for 5 days. The therapeutic effect was evaluated by the eradication of these bacteria from the urine, the kidney and stones, inhibition of growth of stones, and also a value of BUN. The urinary excretion rates of CFLP and CAZ was also determined (20 mg/kg). In result, CFLP significantly more effective in the eradication of P. mirabilitis, P. aeruginosa and E. faecalis from the urine, the kidney and stones than the control than the control (p < 0.05). Furthermore, CFLP significantly more effective in the eradication of P. aeruginosa from the urine and also E. facalis from the urine and stones (p < 0.05). Meanwhile, CAZ significantly more effective in the eradication of P. mirabilis from the urine, the kidney and stones and also P. aeraginosa from the kidney and stones than the control. However, CAZ did not show eradicative effect on E. faecalis. The urinary excretion rates of CFLP and CAZ at rats were 59.3% and 59.4%, respectively, within 8 hrs after administration, showing a similar excretion pattern. CFLP exhibited the prominent therapeutic effect on polymicrobial urinary tract infection associated with infectious stones caused by P. mirabilis, P. aeruginosa and E. faecalls. On the basis of these results, it has been strongly suggested that CFLP is highly beneficial in the management of intractable polymicrobial urinary tract infectious in clinic.

Animals↗
PubMed2002

[A critical pneumonia by multidrug-resistant Enterococcus faecium in a chronic hemodialysis patient. A case report].

Enterococcus faecium is usually known as a pathogen of nosocomial infections in compromised patients. Recently it is a problem that some of the E. faecium become resistant to many antibiotics. It is not usual that this pathogen causes pneumonia. We report a community-acquired pneumonia by multidrug-resistant E. faecium in an outpatient who had been receiving hemodialysis for the past year. The patient recovered from pneumonia with vancomycin, but had nosocomial pneumonia caused by MRSA later but recovered.

Aged↗
PubMed2004

[Transferability of vanA gene from vancomycin-resistant Enterococcus faecalis in the digestive tract of specific pathogen-free mice].

We evaluated the transferability of vanA gene from vancomycin-resistant Enterococcus faecalis (VREF) to vancomycin-sensitive E. faecalis (VSEF) in vitro and in vivo. In vitro conjugal transfer experiment by filter mating, the vanA gene of VREF was transferable at the high frequency to VSEF and a mutant strain which cured vanA gene of VREF. In vivo studies in the digestive tract of specific pathogen-free mice pretreated with oral antibiotics, transconjugants were also detected from the feces of a mouse at the lower frequency. However, the colonization of transconjugants was transient. The vanA gene in the donor and the transconjugant strain was confirmed by using a polymerase chain reaction method. These results suggest that VSEF colonizing in the human digestive tract might be developed to VREF by transferring of the vanA gene.

Animals↗