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Enterococcus faecalis septic arthritis in native and prosthetic joints is a very rare infection. A case of an African American man with Enterococcus faecalis prosthetic joint infection is presented as well as a brief review of the literature.
We collected 103 clinical Enterococcus faecium isolates from across Canada, performed standard broth microdilution susceptibility testing, and compared these results with results from the MicroScan Pos MIC Type 6 panel (Baxter Health Care Corp., West Sacramento, Calif.) and the AMS-Vitek Gram-Positive Susceptibility card (Vitek Inc., St. Louis, Mo.). High-level aminoglycoside resistance to gentamicin and streptomycin was detected by a single-concentration agar method with 1,000 micrograms of each aminoglycoside per ml. In addition, we tested the effect of the lower calcium content in broth media as recommended in National Committee for Clinical Laboratory Standards (NCCLS) guideline M7-A2 on the activity of the highly calcium-dependent agent daptomycin. Of the 103 E. faecium isolates, there were 4 and 30 isolates with high-level gentamicin resistance (HLGR) and high-level streptomycin resistance (HLSR), respectively. An additional 39 (37 with HLGR and 36 with HLSR) E. faecium isolates were tested by both the MicroScan and the AMS-Vitek systems. The AMS-Vitek card demonstrated sensitivities of 95 and 82% for detecting HLGR strains and HLSR strains, respectively. The MicroScan panel demonstrated improved sensitivities for detecting HLGR (42 to 97%) and HLSR (64 to 84%) when readings were performed manually instead of being generated automatically. Ampicillin resistance (MIC, greater than or equal to 16 micrograms/ml) was detected in 23 of the 103 E. faecium isolates. Only 14 and 20 of these were detected by the MicroScan panels and AMS-Vitek cards, respectively. beta-Lactamase activity was not detected in any isolates. The lower calcium content in broth media recommended by NCCLS guideline M7-A2 markedly reduced the in vitro activity of daptomycin against Enterococcus spp.
This in vitro study investigates the interaction between aggregation substance (AS), a virulence factor of Enterococcus faecalis, and colonic mucosal fibronectin in normal colon and colon from patients with Crohn's disease. Fibronectin was found to be overexpressed in Crohn's disease compared to normal colon. Compared to E. faecalis OG1X:pAM944 (AS-negative), E. faecalis OG1X:pAM721 (expressing AS) showed a significantly enhanced adhesion to human colonic mucosa in normal colon and in colon from patients with Crohn's disease. Double-staining of fibronectin and AS-positive enterococci showed that colocalization of bacteria and fibronectin was significantly more frequent in Crohn's disease than in normal colon. Preincubation of bacteria with soluble fibronectin caused a significant reduction in the adherence to fibronectin. In conclusion, the interaction between AS and fibronectin plays is an important factor that mediates adhesion of Enterococcus faecalis to colonic mucosa. This might be one of the mechanisms responsible for bacterial translocation of Enterococcus faecalis.
A transcriptional profile of Enterococcus faecalis V583 (V583) treated with erythromycin is presented. This is the first study describing a complete transcriptional profile of Enterococcus. E. faecalis is a common and nonvirulent bacterium in many natural environments, but also an important cause of nosocomial infections. We have used a genome-wide microarray based on the genome sequence of V583 to study gene expression in cells exposed to erythromycin. V583 is resistant to relatively high concentrations of erythromycin, but growth is retarded by the treatment. The effect of erythromycin treatment on V583 was studied by a time course experiment; samples were extracted at five time points over a period of 90 min. A drastic change in gene transcription was seen with the erythromycin-treated cells compared to the untreated cells. Altogether, 260 genes were down-regulated at one or more time points, while 340 genes were up-regulated. Genes encoding hypothetical proteins and genes encoding transport and binding proteins were the two most dominating groups of differentially expressed genes. The gene encoding ermB (EFA0007) was expressed, but not differentially, which indicated that other genes are important for the survival and growth maintenance of V583 treated with erythromycin. One of these genes is a putative MsrC-like protein, which was up-regulated at all time points studied. Other specific genes that were found to be up-regulated were genes encoding ABC transporters and two-component regulatory systems, and these may be genes that are important for the specific response of V583 to erythromycin.
Conjugative plasmids transfer in Enterococcus faecalis is inducted by sex pheromones. The pheromone is excreted by recipient cells and induces expression of aggregation protein AS in donor cells. This protein is involved in formation of matting aggregates. Use of flow cytometry and anti-As monoclonal antibodies allowed collect of interesting data pheromone response. However, according to our knowledge, no study focused on unspecific influence on particular pheromone for plasmid-free recipient strains. Six pAD1 (-) and tree pAD1 (+) Enterococcus faecalis stains were cultivated for 18h in BHI, with and without cAD1 pheromone (Sigma, Germany), respectively. The bacteria were washed, stained with carboksyfluorescein (FCDA, and analyzed by flow cytometry in FACS BD scan cytometr. Relative fluorescence and size of aggregation was used to compare influence on particular strains. Surprisingly, the results shows divergence in fluorescence, size of aggregates and degree of correlation between fluorescence of aggregates and their sizes among pAD1(-) strains, allowing for distinguish of two groups. Three of studied strains have higher fluorescence than pAD (+) stains. Correlation between fluorescence and size of aggregates, significant higher than in pAD1(+) stains, decrease from r = 0.88 to r=0.74 in reaction to cAD1. The strains if other group fluorize with lower intensity than pAD1 (+). Furthermore, 30.4% pAD1 (-) of second group have no detectable fluorescence. In contrast to pAD1 (-) ) strains of the first group and pA1 (+) strains, low (r=0.55) correlation between fluorescence and size of aggregates of group II increase up to r=0.74 after incubation with cAD1 pheromone. Previous study of these pAD1 (-) strains, currently assigned to group II, shown their low frequency of collecting aph2" gene encoded on other conjugative plasmid, pMG. According to these results, such flow cytometric analysis may be used to predict ability of strain to collect unrelated conjugative plasmid.
AIM: To evaluate the potential of ozone as an antibacterial agent using Enterococcus faecalis as the test species. METHODOLOGY: Ozone was produced by a custom-made bench top generator and its solubility in water determined by ultraviolet (258 nm) spectrophotometric analysis of solutions through which ozone was sparged for various time-periods. The antibacterial efficacy of ozone was tested against both broth and biofilm cultures. Ozone was sparged for 30, 60, 120 and 240 s, through overnight broth cultures of a strain of E. faecalis (E78.2) and compared with those that were centrifuged, washed and resuspended in water. Enterococcus faecalis (E78.2) biofilms were grown on cellulose nitrate membrane filters for 48 h and suspended in water through which ozone gas was sparged with stirring for 60, 120 and 240 s in a standard fashion. In a separate test, biofilms were also exposed to gaseous ozone. Sodium hypochlorite (NaOCl) was used as a positive control. All experiments were repeated four times. RESULTS: There were significant (P < 0.05) reductions of bacteria in the unwashed (2 log(10) reductions) and washed (5 log(10) reductions) broth cultures following 240 s applications. Biofilms incubated for 240 s with ozonated water showed no significant reduction in cell viability attributable to ozone alone, whereas with NaOCl no viable cells were detected over the same time. Gaseous ozone applied for 300 s had no effect on these biofilms. CONCLUSIONS: Ozone had an antibacterial effect on planktonic E. faecalis cells and those suspended in fluid, but little effect when embedded in biofilms. Its antibacterial efficacy was not comparable with that of NaOCl under the test conditions used.
Thirty-two Enterococcus faecium strains and 33 Enterococcus faecalis strains were tested for their susceptibility to the ionophore antibiotics salinomycin, narasin, monensin, and lasalocid. Enterococcal strains originated from poultry in which these products are in use as coccidiostats, and from pigs in which these products are allowed as growth promoters. Resistance against salinomycin and narasin in enterococci was frequent among poultry strains, whereas in pig strains, resistance was less common. No resistance was found against monensin and lasalocid. Full cross resistance between salinomycin and narasin was evident. There was no cross resistance between these two ionophores and monensin and lasalocid.
Enterococcus faecalis ssp. liquefaciens S-48 (producer of the peptide antibiotic AS-48) and its mutant B-48-28 (AS-48-) secrete the bacteriocin Bc-48. This substance has been purified to homogeneity from culture supernatants of strain B-48-28; it consists of a protein (80 kDa) stable from pH. 5.5 to 9.0 and sensitive to temperatures above 45 degrees C and to proteases. Its inhibitory spectrum is restricted to strains of Enterococcus faecalis. Bc-48 inhibits protein synthesis but does not affect amino acid uptake. A partial reduction of cell viability, together with autolysis, is also observed. Bc-48 differs from peptide AS-48 in both its molecular properties and mode of action.
This investigation had an aim to establish the incidence of Enterococcus faecalis in vaginal smears and its correlation with antibiotics used for the treatment of genital and extragenital diseases, as well. By this prospective study 300 women in reproductive period have been involved. An average age was 34.5 years and 282 of them are married. They have been divided in 4 groups, 75 in every group. First group consisted women who have not been treated by an antibiotic in last 6 months; second group--women who have been treated due to infections of genital tract; third group--women were treated for unspecific colpitis and last one group were women treated for extragenital infections. A special designated questionnaire has been used to collect data from patients. A vaginal smears for microbiology examination has been taken at the Gynecological Clinic and Clinic for Infective diseases of The University Clinical Center Tuzla from patients of group I, II and IV and at the Outpatient Clinic from patients of group III. Enterococcus faecalis has been found in 112 patients (37.33%); in first group in 13 (17.33%) cases, in second group in 26 (34.66%), in third group 39 (52%), and in last group in 34 (45.33%) patients, which significantly different. Investigation on sensitivity showed a minimal sensitivity on Penicillin and Streptomycin and no resistance on Vancomycin. In conclusion, it could be said that Enterococcus faecalis was found in 17.33% patients who has not been treated by antibiotics and in 44% who used antibiotics, which differ significantly (p<0.01).
Late-onset septicemia due to Enterococcus faecalis is common among very low-birth weight neonates. These infants have low concentrations of placentally derived IgG and developmentally low levels of complement. The aim of the present study was to determine the contribution of antibody to in vitro neutrophil-mediated phagocytosis of E. faecalis. Antibody alone, as contained in an adult serum pool heated to inactivate complement, promoted only a modest reduction in the initial bacterial inoculum (50 +/- 12%) for 6 of 10 E. faecalis bacterial strains tested and allowed growth of the other four strains. In the presence of complement, NHS promoted > or = 90% reduction in the initial bacterial inoculum of two representative strains at serum concentrations as low as 0.5%. Hypogammaglobulinemic serum supported similar activity only at concentrations above 5%. Purification of IgG and IgM fractions from NHS revealed that IgM had the higher specific activity to promote phagocytic activity. Absorption to remove specific antibody significantly reduced bactericidal activity by normal human serum, complement-deficient sera, and hypogammaglobulinemic serum. Reconstitution of hypogammaglobulinemic serum with antibody as contained in 1% heated normal human serum or in immune globulin for intravenous use (1200 mg/dl) restored phagocytic activity. Thus, E. faecalis-specific antibody enhances PMN-mediated killing of this organism. Adjunctive therapy with intravenous immunoglobulin could augment the host response to enterococcal infections in infancy.
Enterococcus faecalis is one of the leading causes of hospital-acquired infections, and indwelling medical devices are especially prone to infection. E. faecalis expressing aggregation substance (Agg) adheres to biomaterial surfaces by means of positive cooperativity, i.e. the ability of one adhering organism to stimulate adhesion of other organisms in its immediate vicinity. In this study, atomic force microscopy (AFM) was used to measure the specificity and non-specificity of interaction forces between E. faecalis cells with and without Agg. Bacteria were attached to a substratum surface and a tip-less cantilever. Two E. faecalis strains expressing different forms of Agg showed nearly twofold higher interaction forces between bacterial cells than a strain lacking Agg [adhesive force (F(adh)), -1.3 nN]. The strong interaction forces between the strains with Agg were reduced after adsorption of antibodies against Agg from -2.6 and -2.3 nN to -1.2 and -1.3 nN, respectively. This suggests that the non-specific interaction force between the enterococci amounts to approximately 1.2 nN, while the specific force component is only twofold stronger. Comparison of the results of the AFM interaction forces with the positive cooperativity after adhesion to a biomaterial in a parallel-plate flow chamber showed that in the absence of strong interaction forces between the cells, positive cooperativity was also absent. In conclusion, this is believed to be the first time that the influence of specific antibodies on interaction forces between E. faecalis cells has been demonstrated by AFM, thereby experimentally distinguishing between specific and non-specific force components.
A library of insertional mutants of Enterococcus faecalis was constructed; it allowed the isolation and the characterization of 10 mutants affected in resistance to bile salts. Insertion loci of two mutants corresponded to genes of unknown function, while the amino acid sequences deduced from the other loci were homologous to proteins related to DNA repair, oxidative response, transcriptional regulation, dGTP hydrolysis, membrane composition, or cell wall synthesis. Further characterization of one mutant revealed that the insertion within the E. faecalis sagA gene led to a decrease of the resistance towards numerous independent physicochemical stresses, to modifications of the cell wall integrity, and to perturbations of cell division with septation anomalies.
The ability of Enterococcus faecalis to survive starvation for long periods in the obturated root canal is likely to be an important factor in the pathogenesis and maintenance of a persistent infection after endodontic treatment. The response of E. faecalis to starvation survival in water and glucose-, phosphate- or amino acid-limited chemically defined medium was studied, along with the capacity for growth and recovery of starved cells of E. faecalis in pooled human serum. After an initial rapid fall in cell numbers, a small remaining population of E. faecalis was able to survive in water for over 4 months and in nutrient-limited media for extended periods. A high cell density at the onset of starvation was critical for the ability of E. faecalis to endure prolonged nutrient limitation. Upon starvation, a static population of starved cells developed and were apparently in a minimal metabolic state, since blocking cell wall synthesis with penicillin G or inhibiting DNA synthesis with norfloxacin during starvation resulted in limited change in the rate of loss of viable cells. In 50% serum, E. faecalis grew, then stabilized at a relatively constant population of 106 colony-forming units/ml for 4 months, irrespective of the initial cell density. In summary, E. faecalis is capable of withstanding prolonged periods of starvation in a minimal metabolic state provided that there is a high cell density at the onset of starvation. Starved cells were capable of recovery upon addition of human serum.
Resistance to linezolid among Enterococcus faecium and Enterococcus faecalis isolates has been reported in patients who receive a prolonged course of the drug. We report two cases of linezolid-resistant Enterococcus faecalis that occurred in patients who previously received linezolid for infections with vancomycin-resistant Enterococcus faecium. Both isolates had the G2576U mutation in the 23S rRNA previously reported in isolates of Enterococcus faecium. The number of gene copies mutated in the 23S rRNA correlated with the level of resistance.
Enterococcus faecalis is a commensal bacterium that colonizes the gut of humans and animals and is a major opportunistic pathogen, known for causing multidrug-resistant healthcare-associated infections (HAIs). Its ability to thrive in diverse environments and disseminate antimicrobial resistance genes (ARGs) across ecological niches highlights the importance of understanding its ecological, evolutionary, and epidemiological dynamics. The CRISPR2 locus has been used as a valuable marker for assessing clonality and phylogenetic relationships in E. faecalis. In this study, we identified a group of E. faecalis strains lacking CRISPR2, forming a distinct, well-supported clade. We demonstrate that this clade meets the genomic criteria for classification as a novel subspecies, here referred to as "subspecies B." Through a comprehensive pangenome analysis and comparative genomics, we explored the adaptive ecological traits underlying this diversification process, identifying clade-specific features and their predicted functional roles. Our findings suggest that the frequent isolation of subspecies B from meat products and processing facilities may reflect dissemination routes involving environmental contamination (e.g., water, plants, soil) from avian species. The absence of key virulence traits required for pathogenicity in mammals, particularly humans, and the lack of clinically relevant resistance determinants indicate that subspecies B currently poses minimal threat to public health compared with the broadly disseminated "subspecies A." Nevertheless, the unclear potential for genetic exchange between these subspecies and the frequent association of subspecies B with food sources calls for continued genomic surveillance of E. faecalis from a One Health perspective to detect and mitigate the emergence of high-risk variants in advance.IMPORTANCEExploring intraspecific genetic variability in generalist bacteria with pathogenic potential, such as Enterococcus faecalis, is a key to uncovering stable evolutionary trends. By screening the CRISPR2 locus across a representative set of genomes from diverse sources, this study reveals a previously unrecognized lineage within the population structure of E. faecalis, associated with underexplored nonhuman and nonhospital reservoirs. These findings broaden our knowledge of the species' genetic landscape and shed light on its adaptive strategies and patterns of ecological dissemination. By bridging phylogenetic patterns with variation in genetic defense systems and accessory traits, the study generates testable hypotheses about the genomic determinants and corresponding selective pressures that shape the species' behavior and long-term dissemination. This work offers new perspectives on the eco-evolutionary dynamics of E. faecalis and highlights the value of genomic surveillance beyond clinical settings, in alignment with One Health principles.
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.
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.
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 A 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 A, alpha = gamma = 90.0, beta = 119.1 degrees. A selenomethionine derivative was prepared and is currently being tested in crystallization trials.