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PubMed1992

A truncated Tn916-like element in a clinical isolate of Enterococcus faecium.

A 58.7-kb nonconjugative plasmid (pKQ1) previously reported in a clinical isolate of Enterococcus faecium was found to contain both a tetM and an erythromycin resistance (erm) determinant. The plasmid contained a region homologous to the A, F, H, and G HincII fragments of Tn916. However, the 4.8-kb B fragment of Tn916 which contained the tetM determinant was replaced by a 7.3-kb fragment, and the 3.6-kb HincII C fragment of Tn916 was missing. An element homologous to Tn917 was juxtaposed to the truncated Tn916-like element. The Tn917-like element was similar in size to the erm transposon Tn917 as determined by a ClaI restriction digest which spanned approximately 99% of the transposon. When Bacillus subtilis or Streptococcus sanguis were transformed with pKQ1, no zygotically induced transposition of the tetM element was detected. Similarly no transposition of the Tn917-like element was detected.

Bacillus subtilis↗
PubMed1992

Transfer of a plasmid determining bacteriocin Bc-48 production and immunity, and response to sexual pheromones in Enterococcus faecalis S-48.

Production of bacteriocin Bc-48 by Enterococcus faecalis S-48 is encoded by the conjugative plasmid pMB1, which is approximately 90 kb and also responds to sex pheromones of E. faecalis OG1X. Mutants harboring deleted forms of this plasmid (pMB1-del, 75 kb) have lost both the phenotype Bc-48 (production and immunity) and the clumping response. The conjugal transfer of pMB1 to E. faecalis OG1X results in the acquisition by this strain of both bacteriocin production and immunity and also the clumping response. In the transconjugants isolated, the bacteriocinogenic trait is associated with a smaller plasmid (52 kb), which we call pMB1-1. The relationship among plasmids pMB1, pMB1-del, and pMB1-1 has been demonstrated by DNA hybridization. Plasmid pMB1-1 has been transferred with high frequency to E. faecalis mutants cured of Bc-48 production (carrying pMB1-del), conferring to them the Bc-48 trait and clumping response. In the transconjugants from a second mating, pMB1-1 and pMB1-del coexist without appreciable segregation.

Bacterial Proteins↗
PubMed1990

Enterococcus faecalis and otitis media with effusion. How to treat.

Although microorganisms are cultured in only one out of 3 middle ear effusions, viable and non-viable bacteria are presumed to be responsible in part for otitis media with effusion (OME). Because of this association, antibiotics in sublethal, bacteriostatic, or bacteriocidal concentrations are frequently used as non-surgical therapy for OME. Antibiotic treatment is predicated on the assumption that microorganisms responsible for OME are the same ones which produce acute otitis media. This may not always be the case. Enterococcus faecalis (formerly known as beta-hemolytic group D Streptococcus) was isolated in pure culture from 3 middle ears of two patients with OME. The significance of the isolation of this bacteria, an enteric organism which is infrequently found in upper respiratory tracts, is its lack of susceptibility to the usually prescribed oral antibiotics. In each of the children, failure to respond to antibiotics led to tympanocentesis and culture followed by middle ear drainage with insertion of middle ear ventilating tubes. Unless intravenous antibiotics are used, surgical drainage should be the procedure of choice when E. faecalis is found in the middle ear.

Child, Preschool↗
PubMed1993

Na+ and K+ transport by 4-chlorophenylurethane-monensin in Enterococcus hirae de-energized and energized cells studied by 23Na-NMR and K+ atomic absorption.

Na+ and K+ movements induced by 4-chlorophenylurethane-monensin, which presents an inverted ion selectivity (K+ > Na+) in model systems compared with monensin, were followed on Enterococcus hirae cells by 23Na-NMR and K+ atomic absorption. For de-energized cells, the urethane derivative is much more selective for K+ than monensin, but only at low concentrations (10(-3)-10(-4) mM). For higher concentrations, as previously shown for monensin, the sodium and potassium movements are driven by the ion gradients present. On energized cells, both K+ and Na+ gradients were highly perturbed, and this can be related to the higher toxicity in mice and bacteria for this derivative.

Biological Transport↗
PubMed1995

Identification of Enterococcus species isolated from foods of animal origin.

Enterococci isolated from a large variety of fresh and prepared foods of animal origin during routine microbiologic control tests in a distribution firm, were identified to species level using API 20 STREP galleries supplemented with conventional tests, rapid ID32 STREP galleries and SDS-PAGE analysis. API 20 STREP tests correctly identified 77% of the strains, mainly Enterococcus faecium and E. faecalis. A simple presumptive identification scheme based on pigmentation, tetrazolium reduction and acid production from mannitol and raffinose identified 90% of the strains. More complex procedures were necessary to identify the remaining strains. Nearly all strains isolated from hard cheeses and prepared cheese-meat combinations were identified as E. faecium while E. faecalis was the most frequent species in crustaceans. In meat and in prepared meat products E. faecium, E. faecalis and less frequently E. hirae/E. durans were found. Three of four E. gallinarum strains were isolated from products containing turkey meat.

Animals↗
PubMed1994

Isolation and characterization of two bacteriocins produced by Enterococcus faecium strains inhibitory to Listeria monocytogenes.

A total of 4000 bacterial strains were isolated from milk, cheese and from different samples taken on the farm (silage, faeces) and screened for their antimicrobial activity against Listeria monocytogenes. Only eight of the almost 4000 strains exhibited inhibitory activity in the cell-free supernatant fluid. Two different Enterococcus strains (RZS C5 and RZS C13) were chosen for further study. Plasmid profile analysis of both revealed that RZS C5 contained a 4 kb plasmid while RZS C13 contained a 23 kb plasmid. The inhibitory compounds were proteinaceous and active against all Listeria spp. tested while most of the lactic acid bacteria were insensitive. Weak inhibition was also detected against Clostridium perfringens and some Bacillus spp. Cross-inhibition tests showed different profiles. The bacteriocins were heat-resistant and were very stable during storage, especially at low pH values. Their molecular weight was estimated at +/- 3.0 kDA. Addition of 200 AU/ml of bacteriocin resulted in an initial rapid decrease of the number of viable L. monocytogenes cells followed by slower a logarithmic decrease.

Animals↗
PubMed1994

Growth of Enterococcus, Lactococcus and Streptococcus strains and environmental isolates in liquid media and their reactions on BEEA.

Growth of known species of Enterococcus, Lactococcus and Streptococcus and Aerococcus viridans in selective and nonselective liquid media routinely used to enumerate faecal streptococci was measured optically at different temperatures. Growth of environmental isolates was measured in some of these media. Growth of the reference strains on Bile esculin azide agar at elevated incubation temperatures was tested. The results revealed only minor differences between media but strong influence of incubation temperature. Some media tended to yield higher cell densities than others. For many species the inoculum size affected maximum turbidity. To combine selective media with selective incubation temperatures seems to be necessary to achieve satisfactory reliability in traditional liquid enumeration methods for faecal streptococci. Because of the diversity of this group, optimal selectivity and recovery can hardly be achieved simultaneously.

Agar↗
PubMed1996

Purification, partial characterisation and mode of action of enterococcin EFS2, an antilisterial bacteriocin produced by a strain of Enterococcus faecalis isolated from a cheese.

Enterococcus faecalis strain EFS2, isolated from the surface of a traditional cheese, produced a bacteriocin active against Gram-positive bacteria including Listeria spp. and some Staphylococcus aureus strains. The bacteriocin, named enterococcin EFS2, has been purified to homogeneity by ammonium sulphate precipitation and reversed-phase high performance liquid chromatography (RP-HPLC). The molecular weight was determined by mass spectrometry to be 7149.6. The amino acid composition of enterococcin EFS2 revealed that it contained 67 amino acid residues and had a blocked amino-terminal end. Enterococcin EFS2 induced viability loss, efflux of K+ ions and ATP, and cell lysis. Kinetic study of bactericidal activity of enterococcin EFS2 on Listeria innocua strain LIN11 indicated slower cell destruction than by nisin. At pH 7.0, the activity of enterococcin EFS2 was the highest at 35 degrees C and was lost at 15 degrees C. The bacteriocin was more active against L. innocua strain LIN11 in broth adjusted to pH 6.0, 7.0 and 8.0 than to pH 4.5 at 30 degrees C.

Amino Acids↗
PubMed1995

Long-term effects of Enterococcus faecium SF68 versus lactulose in the treatment of patients with cirrhosis and grade 1-2 hepatic encephalopathy.

In 40 patients with cirrhosis on a dietary protein regimen of 1 g/kg b.w., we determined the effect on chronic hepatic encephalopathy of long-term administration of Enterococcus faecium (SF68) versus lactulose. The patients received one of the two treatments for three periods of 4 weeks, each separated by drug-free 2-week intervals. The efficacy of treatment was assessed by arterial blood ammonia concentration, mental status, number connection (Reitan's part A) test and flash-evoked visual potentials. At the end of the third period the reduction in both blood ammonia concentrations and Reitan's test times was more enhanced in patients on SF68 than in patients on lactulose. Furthermore, while patients on lactulose tended to return to basal values during drug-free intervals, responders in the SF68 group maintained improvement throughout the study. In conclusion, SF68 is at least as useful as lactulose for the chronic treatment of chronic hepatic encephalopathy; it has no adverse effects, and treatment can be interrupted for 2 weeks without losing the beneficial effects.

Adult↗
PubMed1996

Effect of orally administered heat-killed Enterococcus Faecalis FK-23 preparation on neutropenia in dogs treated with cyclophosphamide.

Dogs injected intravenously for 3 days with cyclophosphamide (CY) at a dose of 10 mg/kg were given 100 mg/kg of Enterococcus faecalis FK-23 preparation (FK-23) perorally for 14 days to confirm the beneficial effects of the latter drug in neutropenic dogs when orally administered. Although FK-23 treatment did not inhibit CY-induced neutropenia, it augmented neutrophil-reconstituting capacity in these dogs. Increases in the myeloid/ erythroid ratio and neutrophilic lineages were found in the bone marrow of FK-23 administered dogs. The oral administration significantly restored the reduced activity of neutrophil phagocytosis and chemiluminescence in dogs treated with CY. These findings indicate that FK-23 administered perorally not only augments neutrophil reconstitution through the activation of bone marrow but also functions in dogs treated with CY. It may thus be a useful supportive agent to reduce the adverse side-effects associated with the administration of chemotherapeutic agents such as CY.

Administration, Oral↗
PubMed1991

Hygienic hand disinfection for the removal of epidemic vancomycin-resistant Enterococcus faecium and gentamicin-resistant Enterobacter cloacae.

An outbreak strain of Enterococcus faecium, bearing plasmid-mediated vancomycin resistance, and an epidemic gentamicin-resistant, multiply-resistant strain of Enterobacter cloacae, both survived well on fingertips of three volunteers for up to 30 minutes after inoculation. Hand disinfection of inoculated fingers with 60% isopropyl alcohol, or with alcoholic chlorhexidine, reliably gave a 4 log10 reduction of both test organisms. Enterobacter cloacae could not be detected in any finger washings, even by enrichment culture. Chlorhexidine digluconate and povidone-iodine were also effective against E. faecium and Ent. cloacae, giving 4 log10 reductions, but finger washings taken after disinfection yielded low counts of the test strains, e.g. less than 45 recoverable colony forming units (cfu) per finger. Handwashing with soap and water was the least reliable method. The epidemicity, serious antimicrobial multiple resistance and survival on finger-tips of these two strains justifies the use of handwashing agents which have maximum effect. The rapid bactericidal (and residual) activity of alcoholic chlorhexidine suggests that, on the basis of present evidence, it is the preferred agent for hygienic hand disinfection against such strains.

Adult↗
PubMed1995

The emergence of Enterococcus faecium resistant to glycopeptides and other standard agents--a preliminary report.

We describe the emergence of vancomycin-resistant (VmR) Enterococcus faecium on a liver unit. Over a 22 month period, 110 patients acquired VmR E. faecium. Ribotyping identified 116 patient isolates. Five ribotypes accounted for 78% of patient isolates, the maximum number of patient isolates of a single ribotype was 37, and five clusters of four ribotypes were found. Seven patients acquired more than one ribotype. Environmental sampling yielded VmR E. faecium of the same ribotype as concurrent patient isolates. Clinical specimens from 38 liver transplant patients yielded VmR E. faecium and these were compared to 29 who acquired vancomycin-sensitive (VmS) E. faecium. Logistic regression analysis indicated that duration of admission was the only independent risk factor for acquisition of VmR E. faecium.

Anti-Bacterial Agents↗
PubMed1994

Colonization pattern of vancomycin-resistant Enterococcus faecium.

BACKGROUND: Vancomycin-resistant Enterococcus faecium is increasingly recognized as a serious problem by hospital epidemiologists. Understanding its colonization patterns may help in designing strategies to control its nosocomial spread in the hospital. METHODS: Twenty patients, selected at random, with vancomycin-resistant E. faecium isolated from cultures of various body sites were studied to determine sites of colonization. For 12 of these patients, cultures of environmental surfaces of their rooms and wards were also obtained. RESULTS: Eighteen patients (90%) had vancomycin-resistant E. faecium grown in stool cultures. In five patients (25%), vancomycin-resistant E. faecium was cultured from other sites: groins (four), popliteal fossae (three), mouth (one), and an open wound site (one). Patients with positive cultures from the groins and popliteal fossae also had growth of vancomycin-resistant E. faecium in cultures of diarrhea soiling those sites. No patients had the organism isolated from their nares. Vancomycin-resistant E. faecium grew in cultures obtained from bedside stand tables, over-bed tables, used linen, and bedside rails. CONCLUSIONS: In the 20 patients studied, colonization of vancomycin-resistant E. faecium was limited chiefly to the enteric tract. Absence of colonization of such a secluded area with poor antibiotic penetrability as the nares is encouraging. In our study, vancomycin-resistant E. faecium was isolated from various environmental surfaces from the rooms and wards of patients with vancomycin-resistant E. faecium in their stools.

Administration, Oral↗
PubMed1990

Tn3702, a conjugative transposon in Enterococcus faecalis.

Enterococcus faecalis strain D434 was found to carry on its chromosome a determinant encoding tetracycline-minocycline resistance (Tcr-Mnr) and to harbor both an R plasmid and a cryptic conjugative plasmid, pIP1141. The determinant coding for Tcr-Mnr was located on a conjugative transposon, designated Tn3702. The transposition of Tn3702 on to both pIP1141 and the hemolysin plasmid pIP964 yielded different derivatives each of which contained an 18.5-kilobase insert. The structure of Tn3702 is similar to that of the conjugative transposon Tn916.

Conjugation, Genetic↗
PubMed1991

Enterococcus faecalis: specific and non-specific interactions with human polymorphonuclear leukocytes.

In previous studies we have demonstrated that the ability of Enterococcus faecalis to adhere to and to be internalized in human urinary tract epithelial cells, Girardi Heart cells and human polymorphonuclear leukocytes (PMNs), was dependent on whether the strain had been isolated from urinary tract infections (UTI) or endocarditis (EN) respectively. These properties were further modified by growth of the organism in human serum. In the present report, using competition assays we show that adhesins containing a D-glucose moiety play a role in mediating the interactions between human PMNs and E. faecalis strains isolated from UTI and grown in brain-heart infusion broth (BHIB). On the other hand, adhesins containing both D-glucose and D-galactose moieties were involved in the interactions between PMNs and serum grown UTI isolates or EN isolates grown in either BHIB or human serum. Moreover, the impairment in the association between both UTI and EN strains after growth in serum appears to be at least partially related to a decrease in enterococcal surface hydrophobicity.

Adult↗
PubMed1991

Transposon mutagenesis in Staphylococcus epidermidis using the Enterococcus faecalis transposon Tn917.

We transformed a clinical Staphylococcus epidermidis isolate with the Enterococcus faecalis transposon Tn917-carrying plasmid pTV1. Loss of plasmid replication was observed at 47 degrees C. Tn917 transposes efficiently and apparently randomly. The transposition frequency could be stimulated by erythromycin. Transposon mutagenesis in S. epidermidis provides a means for genetic study of the various virulence factors of this pathogen.

Blotting, Southern↗
PubMed1992

Biosynthesis of modified peptidoglycan precursors by vancomycin-resistant Enterococcus faecium.

In the presence of bacitracin, vancomycin-resistant Enterococcus faecium (vanA phenotype) accumulate UDP-N-acetylmuramyl(UDP-Mur-NAc)-tetrapeptide and a UDP-MurNAc-depsipentapeptide containing lactate substituted for the carboxy-terminal-D-alanine residue. In an in vitro peptidoglycan polymerization assay, the modified precursors function and confer resistance to vancomycin.

Amino Acid Sequence↗
PubMed1992

Conjugal transfer of plasmid-borne bacteriocin production in Enterococcus faecalis 226 NWC.

Enterococcus faecalis 226 NWC, isolated from natural whey cultures utilized as starter in water-buffalo Mozzarella cheese manufacture, produces a bacteriocin, designated Enterocin 226 NWC, which is inhibitory to Listeria monocytogenes. Plasmid analysis of E. faecalis 226 NWC showed a single 5.2-kb plasmid, pEF226. In conjugation experiments, pEF226 was transferred into a plasmid-free strain of E. faecalis JH2-2. The transfer required direct cell-to-cell contact and was not inhibited by DNase. The identity of conjugation was confirmed by digestion with SmaI restriction endonuclease and subsequent pulsed-field gel electrophoresis (PFGE) of the genomic DNA of E. faecalis 226, E. faecalis JH2-2 and of the isolates after the mating. The data indicate that the ability of E. faecalis 226 NWC to produce the bacteriocin is linked to the 5.2-kb conjugative plasmid pEF226.

Bacteriocins↗