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PubMed1991

[A case of Enterococcus faecalis brain abscess in a patient with suprapharyngeal cancer].

A 55-year-old male was admitted to our hospital for the treatment of suspected brain abscess on March 18, 1989. The brain CT scan showed low density area with ring enhancement. After admission, both cefminox 2 g/day and clindamycin 500 mg/day were administered intravenously. On March 29, 1989, the patient developed cerebral herniation suddenly. Therefore emergency burr hole operation was done. Many gram-positive cocci were observed on gram-staining of the aspirated pus. Moreover neutrophils with phagocytosed gram-positive cocci were also observed. Culture of aspirated pus revealed colonies of gram-positive cocci which were subsequently identified as E. faecalis. Same species of bacteria were also isolated from fistula of right mastoid. From both findings of brain CT scan and data of MICs of E. faecalis, it may be suggested that direct infection developed from right mastoiditis to intracranial space. We experienced a severe case who developed cerebral herniation because of brain abscess due to E. faecalis which is an infrequent pathogen of brain abscess.

Brain Abscess↗
PubMed2001

In vitro activity of 19 antimicrobial agents against enterococci from healthy subjects and hospitalized patients and use of an ace gene probe from Enterococcus faecalis for species identification.

We tested 165 enterococcal isolates, biased toward vancomycin resistant (VR) isolates, collected during recent years from fecal samples of healthy subjects and clinical specimens of hospitalized patients (mostly from United States and some from Europe) for susceptibility to 19 antimicrobials. Nosocomial isolates, whether VR or not, were more often highly resistant to aminoglycosides and clindamycin than fecal isolates from healthy community volunteers and more often resistant to erythromycin, chloramphenicol, trimethoprim, levofloxacin and, for E. faecium, ampicillin (93 vs. 0%). Resistance rates were similar between nosocomial and community-fecal isolates for minocycline, rifampin and quinupristin-dalfopristin (Q-D). None of the 165 enterococci tested hybridized with aph(2'')-Ic and aph(2'')-Id probes for recently described gentamicin resistance genes and 37 of the 39 isolates with high level resistance (HLR) to gentamicin hybridized with an intragenic aac(6')-aph(2'') probe. Of the two newer drugs tested, daptomycin MIC90s were 0.25 microg/mL for E. faecalis and 1 microg/mL for E. faecium, regardless of their vancomycin resistance level or source. For Q-D, none of 28 E. faecium from community based healthy subjects in the USA and 7 of 66 E. faecium from hospitalized patients in the United States were resistant. Among these 7 Q-Dr United States isolates and 7 Q-Dr isolates from Europe (MICs of Q-D of 4-8 microg/mL), none hybridized with vat(D) (formerly satA) and vat(E) (formerly satG) DNA probes, indicating the involvement of other mechanism/s of resistance in these isolates. We also demonstrated that an intragenic probe of the gene ace from E. faecalis showed specific hybridizations to all E. faecalis isolates, suggesting the usefulness of this gene for identification of this species.

Adhesins, Bacterial↗
PubMed2001

In vitro antimicrobial activity of several concentrations of sodium hypochlorite and chlorhexidine gluconate in the elimination of Enterococcus faecalis.

AIM: The aim of this study was to assess, in vitro, the effectiveness of several concentrations of NaOCl (0.5%, 1%, 2.5%, 4% and 5.25%) and two forms of chlorhexidine gluconate (gel and liquid) in three concentrations (0.2%, 1% and 2%) in the elimination of E. faecalis. METHODOLOGY: A broth dilution test using 24-well cell culture plates was performed and the time taken for the irrigants to kill bacterial cells was recorded. Isolated 24 h colonies of pure cultures of E. faecalis grown on 10% sheep blood plus Brain Heart Infusion (BHI) agar plates were suspended in sterile 0.85% NaCI solution. The cell suspension was adjusted spectrophotometrically to match the turbidity of a McFarland 0.5 scale. One mL of each tested substance was placed on the bottom of wells of 24-well cell culture plates (Corning, NY), including the control group (sterile saline). Six wells were used for each time period and irrigant concentration. Two mL of the bacterial suspension were ultrasonically mixed for 10 s with the irrigants and placed in contact with them for 10, 30, and 45 s; 1, 3, 5, 10, 20, and 30 min; and 1 and 2 h. After each period of time, 1 mL from each well was transferred to tubes containing 2 mL of freshly prepared BHI + neutralizers in order to prevent a residual action of the irrigants. All tubes were incubated at 37 degrees C for 7 days. The tubes considered to have positive growth were those which presented medium turbidity during the incubation period. Data were analysed statistically by the Kruskal-Wallis test. with the level of significance set at P < 0.05. RESULTS: All irrigants were effective in killing E. faecalis. but at different times. Chlorhexidine in the liquid form at all concentrations tested (0.2%, 1% and 2%) and NaOCI (5.25%) were the most effective irrigants. However, the time required by 0.2% chlorhexidine liquid and 2% chlorhexidine gel to promote negative cultures was only 30 s and 1 min, respectively. CONCLUSIONS: Even though all tested irrigants possessed antibacterial activity, the time required to eliminate E. faecalis depended on the concentration and type of irrigant used.

Anti-Infective Agents, Local↗
PubMed2001

Enterococcus faecalis--a mechanism for its role in endodontic failure.

AIM: The aim of this study was to identify a possible mechanism that would explain how E. faecalis could survive and grow within dentinal tubules and reinfect an obturated root canal. METHODOLOGY: Cells of Streptococcus gordonii DL1, Streptococcus mutans NG8, or E. faecalis JH2-2 were grown in brain heart infusion broth containing various amounts of human serum for 56 days. The ability of the three species to invade dentine and bind to immobilized type I collagen in the presence of human serum was assessed by dentine invasion and microtitre well experiments. RESULTS: All three species remained viable over the period of the experiment when grown in human serum. Cells of all three bacteria were able to invade dentine and bind to immobilized collagen. Both of these properties were inhibited by the presence of collagen in the cell solution. Human serum inhibited dentine invasion and collagen adhesion by S. gordonii DL1 and S. mutans NG8, whilst dentine invasion by E. faecalis JH2-2 was reduced in the presence of serum, but not inhibited, and binding to collagen was enhanced. CONCLUSIONS: It is postulated that a virulence factor of E. faecalis in failed endodontically treated teeth may be related to the ability of E. faecalis cells to maintain the capability to invade dentinal tubules and adhere to collagen in the presence of human serum.

Bacterial Adhesion↗
PubMed2026

Emergence of an optrA-positive Enterococcus faecalis ST699 lineage in animal-derived foods in Beijing, China.

Enterococci from animal-derived foods are key reservoirs for antimicrobial resistance (AMR) in the food chain. However, comparative genomic studies investigating the distribution of the oxazolidinone resistance gene optrA among food- and human-derived Enterococci remain limited. This study assessed linezolid-resistant Enterococci from retail meat and healthy humans in Beijing, China (2023-2024). Among 87 isolates, E. faecalis and E. faecium predominated. Food-derived isolates showed broader resistance profiles than human isolates. Fourteen optrA-positive strains were identified, accounting for 92.9% of food isolates. optrA frequently co-localized with erm(A), ant(9)-Ia, and fexA on Tn554-family transposons, suggesting a potentially transferable multidrug resistance module. Notably, an optrA-positive E. faecalis ST699 clone was identified for the first time in Chinese retail meat. This clone formed a distinct lineage and carried a complete Tn554-optrA island. A representative ST699 isolate exhibited enhanced fitness and virulence potential in the Galleria mellonella model. These findings highlight animal-derived foods as important reservoirs of linezolid-resistant Enterococci and provide genomic evidence consistent with their role as potential sources of optrA-mediated resistance. The emergence of a multidrug-resistant E. faecalis ST699 clone with enhanced fitness characteristics underscores the need for continued surveillance of foodborne antimicrobial resistance within the One Health framework.

Enterococcus faecalis↗
PubMed1995

[Bactericidal activity of combinations of ticarcillin-clavulanic acid or other beta-lactams (amoxicillin, piperacillin-tazobactam, ticarcillin) with gentamicin against Enterococcus faecalis and E. faecium].

MICs of amoxicillin, piperacillin-tazobactam, ticarcillin and ticarcillin-clavulanic acid were determined against 52 clinical strains of E. faecalis and E. faecium. Modal MICs (mg/l) of these antibiotics were 1, 4, 64 and 64, respectively. Bactericidal activity of the beta-lactams was tested at two concentrations (1/2 MIC and 100 mg/l) alone or combined with gentamicin (4 mg/l) against 10 clinical strains of Enterococcus spp. Activity of ticarcillin was not modified by the addition of clavulanic acid (4 mg/l). Time-kill curves showed that all beta-lactams at 100 mg/l were bactericidal after 18 h of incubation (decrease in bacterial counts > or = 3 log10 CFU/ml) against 6 strains of E. faecalis, with MICs of amoxicillin at 1 mg/l and 2 strains of E. faecium with MICs of amoxicillin at 1 and 2 mg/l. Addition of gentamicin resulted in a bactericidal effect at 3 or 6 hours for the great majority of the combinations studied, except against the two strains highly resistant to gentamicin. Combination of every beta-lactam at 1/2 MIC with gentamicin was synergistic (except in case of high level resistance to gentamicin) and prevented bacterial growth but was not bactericidal. Against two strains of E. faecium with high MICs of amoxicillin (8 mg/l), piperacillin-tazobactam (64 mg/l) and ticarcillin-clavulanic acid (512 mg/l), only combinations of amoxicillin 100 mg/l and gentamicin were always bactericidal. In conclusion, against E. faecalis strains, ticarcillin-clavulanic acid tested at 100 micrograms/ml had a bactericidal activity similar to that of the other beta-lactams tested, alone or combined with gentamicin.(ABSTRACT TRUNCATED AT 250 WORDS)

Amoxicillin↗
PubMed2002

Enterococcus faecalis endocarditis.

The increasing usage of cephalosporins, to which the enterococci are resistant, has resulted in the rising number of enterococcal infections worldwide. Enterococci are a normal part of the flora of the human gastrointestinal tract, buccal cavity, perineal skin, vagina, urethra and gallbladder, but may occur as pathogens in a number of sites causing urinary tract infections, intra-abdominal infections, fatal bacteremia, meningitis and endocarditis. A Saudi male who developed enterococcal endocarditis with vegetations on both aortic and mitral valves required mitral and aortic valve replacement. The attention of physicians is drawn to the increasing frequency of enterococcus as a cause of nosocomial infections, the risk factors, and antibiotic resistance pattern including resistance to vancomycin as well as its potential for virulence.

Adult↗
PubMed2003

Physiological and molecular aspects of bile salt response in Enterococcus faecalis.

Analysis of the susceptibility and the acquisition of tolerance in Enterococus faecalis towards bile salts showed a nearly instantaneous killing effect and yielded evidence for homologous tolerance as well as for cross-protections. Two-dimensional (2-D) electrophoresis revealed 45 proteins which are amplified in response to the bile salt treatment. These include a set of seven proteins, the synthesis of which is increased not only with the bile salts but also with multiple sublethal stresses of various nature. Characterisation of the latter (called general stress proteins) showed that at least five of them are related to resistance to bile salts, heat, ethanol, oxidative and alkaline pH stresses and are probably involved in cross-protection development. On the other hand, random mutagenesis of E. faecalis allowed the isolation of 10 bile salt-sensitive mutants. Their characterisation revealed that the mutation loci corresponded to genes related to DNA repair, oxidative response, transcriptional regulation, dGTP hydrolysis, membrane composition or cell wall synthesis. Further characterisation of one mutant revealed that the insertion within the E. faecalis sagA gene led to morphology changes, to perturbations of cell division and to a decrease of the resistance towards several independent physicochemical stresses.

Bacterial Proteins↗
PubMed1991

Effect of NaCl-induced osmotic stress on intracellular concentrations of glycine betaine and potassium in Escherichia coli, Enterococcus faecalis, and staphylococci.

Staphylococci are more salt tolerant than are enterococci or Escherichia coli. They have a more rigid cell wall and higher internal turgor pressure. The mechanisms of NaCl-induced osmotic tolerance among these bacteria were examined by determining the generation of osmoprotective activity of cellular extracts and intracellular concentrations of glycine betaine and potassium (K+) in response to graded amounts of NaCl. Staphylococci as well as E. coli were shown to require choline or glycine betaine to achieve maximal salt tolerance. In response to 0.9 mol/L NaCl, E. coli exhibited a marked increase in osmoprotective activity, a 168-fold rise in glycine betaine, and a 2.3-fold rise in K+. Enterococcus faealis exhibited a small increase in osmoprotective activity, a 9.3-fold increase in glycine betaine, and a twofold increase in K+. In contrast, strains of Staphylococcus aureus, S. epidermidis, and S. saprophyticus were found to have considerably greater osmoprotective activity, glycine betaine, and K+ than other organisms, even in the absence of external osmotic stress. Glycine betaine rose in some strains, but K+ remained virtually unchanged as the concentration of NaCl was increased. The high concentrations of glycine betaine and K+ in staphylococci, even in the absence of osmotic stress, may explain in part their remarkable salt tolerance and high turgor pressure.

Betaine↗
PubMed2003

[Enterococcus faecalis: a multicenter study on antibiotic resistance].

676 E. faecalis strains were listed over a period of 2 years from the Charles Nicolle hospital of Tunis (167 strains), the Habib Bourguiba hospital of Sfax (350 strains) and the National Centre of Bone marrow Transplantation of Tunis (159 strains). Antibiotic sensibility study was realized by the method of the antibiogram, E-test method and the search of penicillinase by cefinase. E. faecalis resulted essentially from services of onco-haematology (24%), external consultations (23%), surgery (18%) and medicine (15%). These strains were isolated especially from urines (54%), coprocultures (15%), bloodcultures (11%) and from pus (9%). Resistance acquired with these strains is raised for erythromycin, tetracyclin and chloramphenicol (81% to 86%), followed by high level resistance to gentamicine (37%). 0.1% of E. faecalis strains have a low level resistance to amoxicillin without production of penicillinase. No resistance to vancomycin was observed.

Amoxicillin↗
PubMed2006

Peptidoglycan O acetylation and autolysin profile of Enterococcus faecalis in the viable but nonculturable state.

The O acetylation of peptidoglycan occurs specifically at the C-6 hydroxyl group of muramoyl residues. Using a combination of high-performance liquid chromatography-based organic acid analysis and carbohydrate analysis by high-pH anion-exchange chromatography, we determined that strains of Entercoccus durans, E. faecalis, E. faecium, and E. hirae produce O-acetylated peptidoglycan. The levels of O acetylation ranged from 19% to 72% relative to the muramic acid content, and they were found to vary with the growth phase of the culture. Increases of 10 to 40% in O acetylation were observed with cultures entering the stationary phase. Cells of E. faecalis in the viable but nonculturable (VBNC) state had the highest levels of peptidoglycan O acetylation. The presence of this modification to peptidoglycan was shown to inhibit the action of hen egg white lysozyme in a concentration-dependent manner. Zymography using sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels containing either O-acetylated or chemically de-O-acetylated peptidoglycan was used to monitor the production of specific autolysins in E. faecalis. Differences in the expression of specific autolysins were observed with the age of the culture, and VBNC E. faecalis produced the highest levels of these enzymes. This technique also permitted classification of the enterococcal autolysins into enzymes that preferentially hydrolyze either O-acetylated or non-O-acetylated peptidoglycan and enzymes that show no apparent preference for either substrate type.

Acetylation↗
PubMed1996

Isolation and structure of staph-cAM373 produced by Staphylococcus aureus that induces conjugal transfer of Enterococcus faecalis plasmid pAM373.

Enterococus faecalis plasmid pAM373 encodes a mating response to the sex pheromone, cAM373, which is secreted from pAM373-free E. faecalis. cAM373-like activity was detected in a culture filtrate of Staphylococcus aureus. The major active substance, termed staph-cAM373, was isolated, and its structure was identified as a H-Ala-IIe-Phe-IIe-Leu-Ala-Ala-OH heptapeptide.

Amino Acid Sequence↗
PubMed1996

Comparative distribution of the serotypes of Enterococcus faecalis isolated from the urine of patients with urinary tract infections and the feces of healthy persons as determined by the slide agglutination reaction.

In 1992, we reported a new scheme for identifying 21 distinct serovars of E. faecalis by the bacterial agglutination reaction. In this study we isolated strains of E. faecalis from the urine of patients with urinary tract infections and serotyped. We also serotyped strains of E. faecalis isolated from the faces of healthy persons. The results showed that serovars 2, 7, 1 and 3 were the major serotypes a distribution on strains of E. faecalis isolated from patients. Serovars 2, 1 and 13 were the major serotypes of the fecal strains isolated from healthy persons. Single serovars were typable of all strains of E. faecalis isolated from patients in 80.6% (395/496) and in 62.4% of the fecal strains. Examination of the hemolytic zone around colonies on horse/sheep blood agar plates showed that beta-hemolytic strains on horse blood agar plate isolated from patients had 36.1% for all isolated strains from patients and 8.3% for fecal strains isolated from healthy persons.

Agglutination Tests↗
PubMed1988

Restriction mapping and hybridization studies of a beta-lactamase-encoding fragment from Streptococcus (Enterococcus) faecalis.

A restriction map of a 5.1-kilobase EcoRI fragment encoding an enterococcal beta-lactamase was prepared and compared with the restriction map of a cloned staphylococcal beta-lactamase gene and with the published maps of several other staphylococcal beta-lactamase genes. Comparison and hybridization studies showed that there were identical restriction sites in the region of the bla structural gene but not in the region surrounding this gene.

DNA Restriction Enzymes↗
PubMed1988

Characterization and comparison of two penicillinase-producing strains of Streptococcus (Enterococcus) faecalis.

We identified two beta-lactamase-positive enterococci. One strain was high-level (MIC, greater than 2,000 microgram/ml) gentamicin resistant; the other was not (MIC, 12.5 microgram/ml). beta-Lactamase production was extrachromosomally mediated in both strains, and both strains showed an inoculum effect reversed by beta-lactamase inhibitors. The strain lacking high-level gentamicin resistance showed synergistic killing with a combination of penicillin, clavulanic acid, and gentamicin.

Ampicillin↗
PubMed2002

In vitro bactericidal activity of piperacillin, gentamicin, and metronidazole in a mixed model containing Escherichia coli, Enterococcus faecalis, and Bacteroides fragilis.

An anaerobic, mixed model assay was used to study the bactericidal activities of piperacillin, gentamicin, and metronidazole, alone and in double- and triple-antibiotic combinations against a polymicrobial suspension of E. coli, E. faecalis, and B. fragilis. Only slight differences were noted with the agents when tested against single (10(5) cfu/mL inoculum) versus polymicrobic suspensions (10(6) cfu/mL final inoculum) of susceptible and resistant organisms. Contrary to previous reports in the literature, metronidazole was not active against E. coli in an anaerobic environment (even in the presence of B. fragilis) nor was the activity of metronidazole reduced against B. fragilis in the presence of E. faecalis. Gentamicin demonstrated excellent activity against E. coli when tested in a Bactron anaerobic chamber (5% hydrogen, 5% CO(2,) 90% nitrogen). The pH of the media was only reduced to 6.3-6.7, considerably higher than the pH range of 5-6 needed to significantly reduce the activity of aminoglycosides.

Air↗