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PubMed2006

In vitro assessment of the effectiveness of chlorhexidine gel and calcium hydroxide paste with chlorhexidine against Enterococcus faecalis and Candida albicans.

OBJECTIVE: The purpose of this study was to compare the effectiveness of various medicaments, including Ca(OH)2/2% chlorhexidine, 2% chlorhexidine gel, and Ca(OH)2 alone, against Enterococcus faecalis and Candid albicans in vitro. STUDY DESIGN: Eighty extracted single-rooted human maxillary teeth were used. After removing the crown, each root was instrumented up to size 50 by using a conventional technique. The root canal was irrigated with ethylenediamine tetra-acetic acid (EDTA) solution to remove smear layer. Then, roots were infected with E faecalis and C albicans. Subsequently, the roots were divided into 4 treatment groups: group 1 was treated with calcium powder hydroxide in distilled water, group 2 was treated with calcium hydroxide powder in 2% chlorhexidine, group 3 was treated with 2% chlorhexidine gel, and group 4 was treated with 0.9% sterile saline serving as negative control. Microbial samples were taken after 7, 15, and 30 days. After incubation, dentine chips were obtained form each root canal and examined microbiologically. The microbiological samples were plated to count colony-forming units in per milligram of dentin. RESULTS: The results showed that the 2% chlorhexidine gel was significantly more effective than calcium hydroxide with 2% chlorhexidine, calcium hydroxide, and control saline solution (P < .05). CONCLUSION: Under the conditions of this study, 2% chlorhexidine gel is effective in the elimination of E faecalis and C albicans from the root canal system. However, to support this in vitro observation, further in vivo studies are needed.

Anti-Infective Agents, Local↗
PubMed2006

Primer sensitivity: can it influence the results in Enterococcus faecalis prevalence studies?

BACKGROUND/OBJECTIVE: Recent polymerase chain reaction (PCR)-based studies have shown significant variability in the prevalence of Enterococcus faecalis cases with nonhealing endodontic infections. This variability may be, at least in part, due to the differences in sensitivities of the primers used. The purpose of this study was to compare the sensitivity of 3 sets of PCR primers which have been reported in the endodontic literature. METHODS: The 3 primers sets used were: group 1) tuf gene-based primers with genus-level specificity; and groups 2 and 3) 16S rDNA-based primers that were E. faecalis specific. Three strains of E. faecalis at concentrations of 10(2)-10(8) cells/mL were included in this study. RESULTS: The PCR amplification of E. faecalis strains with the 3 primer pairs showed that group 1 primers consistently had the highest sensitivity, followed by group 2 and group 3 (P<.0001). CONCLUSION: A tuf-based PCR identification assay followed by direct sequencing would yield accurate and consistent prevalence rates of E. faecalis in endodontic infections.

Bacterial Proteins↗
PubMed2005

Influence of a probiotic Enterococcus faecium strain on development of the immune system of sows and piglets.

The influence of the probiotic bacterium Enterococcus faecium SF68 on the immune system and the intestinal colonization of pigs were determined in a feeding experiment with sows and piglets. Mucosal immunity of the developing piglets was monitored by isolation and detection of intestinal lymphocyte cell populations from the proximal jejunal epithelium and the continuous Peyers patches by the use of flow cytometry. The levels of intestinal IgA in both groups of piglets were compared, as well as total IgG in the serum of sows and piglets. Feces of the sows and intestinal contents of the piglets were taken for determination of total anaerobe and coliform bacterial counts in both probiotic and control groups. Villus length and depth of the crypts were measured in the jejunum of sacrificed piglets to monitor the development of the intestinal mucosal surface amplification. Total serum IgG of the sows appeared to be unaffected. Piglets of both groups showed similar IgG levels up to 5 weeks after birth with a slight tendency toward lower values in the probiotic group. At an age of 8 weeks the total IgG levels of the probiotic animals were significantly lower (p<0.01). No differences were observed in the populations of CD4+ and CD8+ T cells in the Peyers patches. However, the levels of cytotoxic T cells (CD8+) in the jejunal epithelium of piglets of the probiotic group were significantly reduced. The depth of the jejunal crypts and length of the villi were similar in both groups, suggesting the relative T-cell population differences were not due to alterations in the epithelial cell numbers. The total anaerobe and coliform bacterial populations were not significantly affected by the probiotic treatment, either in sows or in the piglets. However, a remarkable decline in the frequency of beta-haemolytic and O141 serovars of Escherichia coli was observed in the intestinal contents of probiotic piglets, suggesting an explanation for the reduction in cytotoxic T-cell populations.

Animals↗
PubMed2003

Polymicrobial keratitis secondary to Burkholderia ambifaria, enterococcus, and staphylococcus aureus in a patient with herpetic stromal keratitis.

PURPOSE: To report polymicrobial keratitis in a patient with herpetic stromal keratitis. The initial infecting organism, Burkholderia ambifaria, has not previously been reported to cause microbial keratitis. METHODS: Clinical evaluation and corneal culture were performed. RESULTS: A 59-year-old-man undergoing topical corticosteroid therapy for herpes simplex stromal keratitis developed corneal infection with B. ambifaria. The organism was reisolated 12 days after initiation of hourly therapy with topical levofloxacin 0.5%. At reculture Staphylococcus aureus and Enterococcus spp. were also isolated. The addition of topical amikacin and vancomycin led to resolution of the microbial keratitis. CONCLUSIONS: Burkholderia ambifaria infected a compromised cornea, exhibited an unusual sensitivity profile, and remained viable after 12 days of therapy with an antibiotic to which it was sensitive by in vitro tests.

Amikacin↗
PubMed2002

Enterococcus faecalis induces inflammatory bowel disease in interleukin-10 knockout mice.

Germ-free interleukin-10 knockout (IL-10 KO) mice developed inflammatory bowel disease (IBD) after they were colonized with a pure culture of Enterococcus faecalis. E. faecalis not only induced IBD (primarily in colon and rectum) but rectal dysplasia and adenocarcinoma was also found in the IL-10 KO mice. Conventional (complex-intestinal flora) IL-10 KO mice developed IBD within 10 to 15 weeks of age and showed more pathology in the cecum (typhlitis) than we observed with E. faecalis-induced IBD in gnotobiotic IL-10 KO mice. Conversely, neither germ-free IL-10 mice nor IL-10 KO mice colonized as adults, with a pure culture of Candida albicans, Escherichia coli, Lactobacillus casei, L. reuteri, L. acidophilus, a Bifidobacterium sp., Lactococcus lactis, or a Bacillus sp. developed IBD during the 25- to 30-week study. E. faecalis is a common intestinal microbe of man and animals that can trigger IBD, dysplasia, and carcinoma in a genetically susceptible murine host.

Animals↗
PubMed1999

Vancomycin-resistant Enterococcus in liver transplant patients.

BACKGROUND: Vancomycin-resistant Enterococcus (VRE) infection is emerging in the transplant population, and there is no effective antibiotic therapy available. The aims of this retrospective review were to (1) investigate the outcome of and (2) identify common characteristics associated with VRE infection and colonization in orthotopic liver transplant (OLTx) candidates. METHODS: From October 1994 through September 1998, 126 isolates of VRE were identified in 42 of 234 OLTx recipients and 5 OLTx candidates who did not proceed to transplantation. Data were collected by patient chart review or from a computerized hospital database. RESULTS: The 1-year mortality rate with VRE infection was 82%, and with VRE colonization, 7%. This mortality rate contrasts with a 14% 1-year mortality for non-VRE transplant patients (P <0.01, infected patients and colonized patients). Characteristics of VRE colonized and infected patients included recent prior vancomycin (87%), coinfection by other microbial pathogens (74%), recent prior susceptible enterococcal infection (72%), concurrent fungal infection (62%), additional post-OLTx laparotomies (47%), and renal failure (Cr >2.5 mg/dL or need for dialysis; 43%). Biliary complications were seen in 52% of post-OLTx VRE-infected or VRE-colonized patients (versus 22% in non-VRE transplant patients, P <0.05). CONCLUSION: VRE infection is associated with a very high mortality rate after liver transplantation. The incidence of biliary complications prior to VRE isolation is very high in VRE-infected and VRE-colonized patients. The most common characteristics of VRE patients were recent prior vancomycin use, recent prior susceptible enterococcal infection, coinfection with other microbial pathogens, and concurrent fungal infection. With no proven effective antimicrobial therapy for VRE, stringent infection control measures, including strict and limited use of vancomycin, must be practiced.

Adult↗
PubMed2003

Successful treatment of vancomycin resistant Enterococcus faecium mediastinitis associated with left ventricular assist devices.

We present 2 cases of vancomycin-resistant Enterococcus faecium mediastinitis associated with left ventricular assist devices in the setting of heart transplantation. Despite complicated operative courses and deep infection secondary to antimicrobial resistant organisms, both patients were successfully treated and have remained infection free in the long term.

Adult↗
PubMed2001

Catalytic properties of Na(+)-translocating V-ATPase in Enterococcus hirae.

V-ATPases make up a family of proton pumps distributed widely from bacteria to higher organisms. We found a variant of this family, a Na(+)-translocating ATPase, in a Gram-positive bacterium, Enterococcus hirae. The Na(+)-ATPase was encoded by nine ntp genes from F to D in an ntp operon (ntpFIKECGABDHJ): the ntpJ gene encoded a K(+) transporter independent of the Na(+)-ATPase. Expression of this operon, encoding two transport systems for Na(+) and K(+) ions, was regulated at the transcriptional level by intracellular Na(+) as the signal. Structural aspects and catalytic properties of purified Na(+)-ATPase closely resembled those of other V-type H(+)-ATPases. Interestingly, the E. hirae enzyme showed a very high affinity for Na(+) at catalytic reaction. This property enabled the measurement of ion binding to this ATPase for the first time in the study of V- and F-ATPases. Properties of Na(+) binding to V-ATPase were consistent with the model that V-ATPase proteolipids form a rotor ring consisting of hexamers, each having one cation binding site. We propose here a structure model of Na(+) binding sites of the enzyme.

Adenosine Triphosphatases↗
PubMed1998

A novel bacteriocin with a YGNGV motif from vegetable-associated Enterococcus mundtii: full characterization and interaction with target organisms.

A novel broad-spectrum antimicrobial peptide produced by vegetable-associated Enterococcus mundtii was purified and characterized, and designated mundticin. To our knowledge, this is the first report on bacteriocin production by this organism. The elucidation of the full primary amino acid sequence of mundticin (KYYGNGVSCNKKGCSVDWGKAIGIIGNNSAANLATGGAAGWSK) revealed that this antimicrobial peptide belongs to the class IIa bacteriocins of lactic acid bacteria which share a highly conserved N-terminal 'YGNGV' motif. Data obtained by computer modelling indicated an oblique orientation of the alpha-helical regions of mundticin and homologous class IIa bacteriocins at a hydrophobic-hydrophilic interface, which may play a role in the destabilization of phospholipid bilayers. The average mass of mundticin, as determined by electron spray mass spectrometry, was found to be 4287.21+/-0.59 Da. With respect to its biological activity, mundticin was shown to inhibit the growth of Listeria monocytogenes, Clostridium botulinum and a variety of lactic acid bacteria. Moreover, it was demonstrated to have a bactericidal effect on L. monocytogenes as a result of the dissipation of the membrane potential, and a loss of intracellular ATP in absence of ATP leakage. Its good solubility in water, and its stability over a wide pH and temperature range indicate the potential of this broad spectrum bacteriocin as a natural preservation agent for foods.

Amino Acid Sequence↗
PubMed1996

Phosphoenzyme formation by purified, reconstituted copper ATPase of Enterococcus hirae.

The Enterococcus hirae CopB ATPase serves in the secretion of excess copper from cells and belongs to the recently discovered, new class of heavy metal transport ATPases. We here report the affinity purification of CopB to near homogeneity and its reconstitution into phospholipid vesicles. In these proteoliposomes, the ATPase formed an acylphosphate reaction intermediate with the gamma-phosphate of ATP. ATPase activity and phosphoenzyme formation were inhibited by vanadate with an I(50) of 0.1 mM. Our results suggest that heavy metal and non-heavy metal ATPases operate by the same underlying mechanism.

Adenosine Triphosphatases↗
PubMed1999

The Enterococcus hirae copper chaperone CopZ delivers copper(I) to the CopY repressor.

Expression of the cop operon which effects copper homeostasis in Enterococcus hirae is controlled by the copper responsive repressor CopY. Purified Zn(II)CopY binds to a synthetic cop promoter fragment in vitro. Here we show that the 8 kDa protein CopZ acts as a copper chaperone by specifically delivering copper(I) to Zn(II)CopY and releasing CopY from the DNA. As shown by gel filtration and luminescence spectroscopy, two copper(I) are thereby quantitatively transferred from Cu(I)CopZ to Zn(II)CopY, with displacement of the zinc(II) and transfer of copper from a non-luminescent, exposed, binding site in CopZ to a luminescent, solvent shielded, binding site in CopY.

Amino Acid Sequence↗
PubMed1999

Enterococcus hirae vacuolar ATPase is expressed in response to pH as well as sodium.

The Enterococcus hirae ntp operon encodes both a vacuolar ATPase, which transports Na+ as well as Li+, and the KtrII K+ transporter. A plasmid, in which the chloramphenicol acetyltransferase gene (CAT) was placed downstream of the ntp promoter, was introduced into a mutant totally defective in Na+ extrusion. The CAT activity of this transformant was increased preferentially by addition of NaCl, but not by LiCl, in the media or by elevating the medium pH, correlating well with the increase in amounts of the ATPase subunits observed by Western blotting. The physiological significance of these responses of the ntp promoter is discussed.

Chloramphenicol O-Acetyltransferase↗
PubMed1992

Differences in the formation of poles of Enterococcus and Bacillus.

The pole of Enterococcus hirae (Streptococcus faecium) is more pointed than that of Bacillus subtilis; i.e. the pole of the former is prolate and the latter is oblate. Both species form their poles by constructing annular additions on the inside surface. In both cases, the thick septum starts to split from the outside before the septum is complete. Physiochemical considerations dictate that the peptidoglycan must be unstretched as laid down. However, it later becomes stressed and may stretch to increase its surface area or to change its shape. Our earlier analysis for B. subtilis demonstrated that, without the addition of new peptidoglycan, the nascent wall is stretched after it is externalized to 1.51 times the original area. The wall of partially formed poles that is already exteriorized continues to deform with further development. For E. hirae, Higgins & Shockman's measurements showed that the completed pole has a surface area 2.18 times larger than a completed septal disk and the wall changes shape very little after exteriorization. A model is presented here for the streptococcus in which the septal wall does not increase its surface area on exteriorization either by expansion or by murein insertion. Instead, the septal wall as it is split and exteriorized twists to become oblique, increasing the inner radius of the incomplete septum. In consequence of this rotation, extra layers of peptidoglycan are added to the inside face of the developing septum. This additional murein forms the more pointed pole shape for E. hirae. This "split-and-splay" model thus refines and extends the surface stress theory of E. hirae developed a decade ago by proposing a source of the extra wall needed for the formation of its prolate, more pointed, pole.

Animals↗
PubMed1997

Inhibition of initial adhesion of uropathogenic Enterococcus faecalis to solid substrata by an adsorbed biosurfactant layer from Lactobacillus acidophilus.

OBJECTIVES: The potency of the Lactobacillus acidophilus RC14 biosurfactant "surlactin" to reduce the initial adhesion of Enterococcus faecalis 1131 was investigated on a hydrophilic and a hydrophobic substratum in a parallel-plate flow chamber, using phosphate-buffered saline and pooled human urine as a suspending fluid. METHODS: A parallel-plate flow chamber with a glass or silicone rubber bottom plate was filled with different biosurfactant solutions of 0, 0.01, 0.1, or 1.0 mg/mL for overnight adsorption (18 hours). Subsequently, the adhesion of E. faecalis on thus prepared biosurfactant layers was observed in situ in phosphate-buffered saline or in urine by automated image analysis. RESULTS: Adsorbed biosurfactant layers caused an important, dose-related inhibition of the initial deposition rate of E. faecalis and the number of adherent bacteria after 4 hours on both hydrophilic glass and hydrophobic silicone rubber, although this effect was stronger in buffer than in urine. For the experiments carried out in urine, the inhibitory effect of the biosurfactant layer was largest when silicone rubber was used rather than glass, whereas no influence of the substratum hydrophobicity on the inhibition of E. faecalis adhesion was noticed for experiments performed in buffer. CONCLUSIONS: The biosurfactant surlactin, as released by several Lactobacillus isolates, might open the way to the development of antiadhesive biologic coatings for catheter materials. It should be considered, however, that these results are preliminary and that the efficiency of the biosurfactant is probably affected not only by the hydrophobicity of the substratum and the suspending fluid, but also by the type of uropathogen involved.

Bacterial Adhesion↗
PubMed2001

Variant esp gene as a marker of a distinct genetic lineage of vancomycin-resistant Enterococcus faecium spreading in hospitals.

In the USA, vancomycin-resistant Enterococcus faecium (VREF) is endemic in hospitals, despite lack of carriage among healthy individuals. In Europe, however, hospital outbreaks are rare, but VREF carriage among healthy individuals and livestock is common. We used amplified fragment-length polymorphism analysis to genotype 120 VREF isolates associated with hospital outbreaks and 45 non-epidemic isolates from the USA, Europe, and Australia. We also looked for the esp virulence gene in these isolates and in 98 VREF from animals. A specific E. faecium subpopulation genetically distinct from non-epidemic VREF isolates was found to be the cause of the hospital epidemics in all three continents. This subpopulation contained a variant of the esp gene that was absent in all non-epidemic and animal isolates. Identification of the variant esp gene will be important in guiding infection-control strategies, and the Esp protein could be a new target for antibacterial therapy.

Bacterial Proteins↗
PubMed2003

Intergeneric transfer of the Enterococcus faecalis plasmid pIP501 to Escherichia coli and Streptomyces lividans and sequence analysis of its tra region.

The nucleotide sequence of the transfer (tra) region of the multiresistance broad-host-range Inc18 plasmid pIP501 was completed. The 8629-bp DNA sequence encodes 10 open reading frames (orf), 9 of them are possibly involved in pIP501 conjugative transfer. The putative pIP501 tra gene products show highest similarity to the respective ORFs of the conjugative Enterococcus faecalis plasmids pRE25 and pAMbeta1, and the Streptococcus pyogenes plasmid pSM19035, respectively. ORF7 and ORF10 encode putative homologues of type IV secretion systems involved in transport of effector molecules from pathogens to host cells and in conjugative plasmid transfer in Gram-negative (G-) bacteria. pIP501 mobilized non-selftransmissible plasmids such as pMV158 between different E. faecalis strains and from E. faecalis to Bacillus subtilis. Evidence for the very broad-host-range of pIP501 was obtained by intergeneric conjugative transfer of pIP501 to a multicellular Gram-positive (G+) bacterium, Streptomyces lividans, and to G- Escherichia coli. We proved for the first time pIP501 replication, expression of its antibiotic resistance genes as well as functionality of the pIP501 tra genes in S. lividans and E. coli.

Base Sequence↗
PubMed2003

Endophthalmitis caused by enterococcus faecalis: antibiotic selection and treatment outcomes.

PURPOSE: To investigate clinical settings, treatment strategies, and visual acuity outcomes of endophthalmitis caused by Enterococcus faecalis and to determine antibiotic sensitivity and resistance patterns. DESIGN: Retrospective, noncomparative, consecutive case series. PARTICIPANTS AND METHODS: Records were reviewed of all patients with culture-positive endophthalmitis caused by E. faecalis evaluated at the Bascom Palmer Eye Institute between January 1, 1990, and December 31, 2001. MAIN OUTCOME MEASURES: Associated prior surgical procedures, clinical features, treatments administered, antibiotic sensitivity and resistance patterns, and final visual outcomes. RESULTS: Endophthalmitis caused by E. faecalis was identified in 29 eyes of 29 patients. The mean follow-up was 17.8 months (range, 0.1-86.7 months). Endophthalmitis caused by E. faecalis was associated with, in order of decreasing frequency, cataract surgery in 12 of 29 eyes (41.4%), trabeculectomy in 8 of 29 eyes (27.6%), penetrating keratoplasty in 4 of 29 eyes (13.8%), combined cataract and trabeculectomy in 3 of 29 eyes (10.3%), seton implantation in 1 of 29 eyes (3.5%), and pupilloplasty in 1 of 29 eyes (3.5%). Resistance patterns among the isolates were the following: vancomycin in 0 of 23 eyes (0.0%), linezolid in 0 of 29 eyes (0.0%), ciprofloxacin in 1 of 14 eyes (7.1%), gentamicin (minimum inhibitory concentration >8 mg/l) in 8 of 16 eyes (50.0%), high-level gentamicin (minimum inhibitory concentration >500 mg/l) in 5 of 29 eyes (17.2%), cefazolin in 7 of 8 eyes (87.5%), and quinupristin and dalfopristin in 29 of 29 eyes (100.0%). Preinfection baseline visual acuities ranged from 20/30 to hand motions. Visual acuities on presentation with endophthalmitis ranged from 2/200 to no light perception. Final visual acuity was better than or equal to 20/50 in two cases (6.9%), 20/60 to 20/400 in three cases (10.3%), 5/200 to hand motions in 10 cases (34.5%), and light perception to no light perception in 14 cases (48.3%). CONCLUSIONS: E. faecalis often is resistant to gentamicin and cephalosporins but was sensitive to vancomycin in all isolates tested. Endophthalmitis caused by E. faecalis usually is associated with poor visual outcomes.

Aged↗
PubMed1994

Endocarditis due to high level gentamicin resistant Enterococcus faecium.

We describe the first reported case in the literature of bacterial endocarditis caused by Enterococcus faecium that was highly resistant to gentamicin. The case is unusual in that it followed a successfully treated Streptococcus sanguis endocarditis. The micro-organism was susceptible only to the glycopeptide antibiotics, vancomycin and teicoplanin and to agents such as pristinamycin and daptomycin which are not routinely available for treatment. It illustrates the therapeutic dilemma posed by serious infections with such micro-organisms and supports previous observations that early heart valve replacement surgery may be necessary to achieve cure of endocarditis due to enterococci which are highly resistant to gentamicin. It further emphasises the importance of screening for high-level aminoglycoside resistance in enterococci in all life threatening enterococcal infections, including endocarditis, septicaemia and meningitis when aminoglycoside-penicillin synergy is required for successful treatment.

Aged↗