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[The lactic acid enterococci Enterococcus faecium and Enterococcus durans: nucleotide sequence diversity in 16S rRNA genes].

Among the strains used as starters for making sour milk products on the territory of the CIS, the bacteria Enterococcus faecium and Enterococcus durans are frequently found. In this work, we studied a new collection of lactic acid enterococci and also obtained more complete data on the nucleotide sequences of 16S rRNA genes in some strains studied earlier and found that most strains had certain distinctions in their 16S rRNA genes as compared with the E. durans and E. faecium genes available in the NCBI database. Based on these data, it is suggested that the strains of lactic acid enterococci represent new, earlier unknown taxa of enterococci that use milk as an ecological niche.

Armenia↗

PubMed2001

Clinical and epidemiological features of Enterococcus casseliflavus/flavescens and Enterococcus gallinarum bacteremia: a report of 20 cases.

The clinical significance of intrinsically vancomycin-resistant enterococci is not yet fully established, as these organisms are infrequently recovered from clinical specimens. We report our experience with 20 cases of Enterococcus gallinarum and Enterococcus casseliflavus/flavescens bacteremia in humans from 1992 through 1998. Sixteen cases of bacteremia were caused by E. gallinarum. Underlying conditions were present in 19 (95%) of the patients and included malignancy, receipt of transplant, and Caroli's disease. Polymicrobial bacteremia was present in 9 patients (45%). E. gallinarum and E. casseliflavus/flavescens, although they are infrequently isolated from clinical specimens, may cause serious invasive infections.

Adolescent↗

PubMed2003

Clinical features and outcomes of bacteremia caused by Enterococcus casseliflavus and Enterococcus gallinarum: analysis of 56 cases.

The clinical significance and virulence potential of Enterococcus casseliflavus/flavescens and Enterococcus gallinarum are still uncertain. We retrospectively analyzed 56 cases of significant bacteremia caused by E. casseliflavus or E. gallinarum. Of these cases, 25 (44.6%) were associated with polymicrobial bacteremia, and 43 (76.8%) were associated with entry via the biliary tract. Resistance to vancomycin was observed in 17 (30.4%) of these 56 patients, and this resistance was significantly associated with E. gallinarum bacteremia (adjusted odds ratio [AOR], 10.56; 95% confidence interval [CI], 2.41-46.27) and bacteremia without biliary tract origin (AOR, 6.74; 95% CI, 1.44-31.67). The crude mortality rate was 13%, and the bacteremia-related mortality rate was 1.9%. In conclusion, bacteremia due to E. casseliflavus and E. gallinarum is commonly associated with biliary tract disease and may be associated with a low risk of mortality.

Adult↗

PubMed2001

Enterococcus haemoperoxidus sp. nov. and Enterococcus moraviensis sp. nov., isolated from water.

A polyphasic taxonomic approach was used to study atypical enterococci isolated from surface waters. All strains were characterized by physiological and biochemical tests as well as by genotyping. The results of biochemical tests and tRNA intergenic length polymorphism analysis (tDNA-PCR) divided all studied strains uniformly into two groups. Because these groups were clearly separated from all enterococcal species described to date, 16S rDNA sequence analysis, DNA base composition analysis and DNA-DNA hybridization of representative strains were done to elucidate the taxonomic position of the analysed groups. On the basis of the results obtained, the names Enterococcus haemoperoxidus (type strain CCM 4851T = LMG 19487T) and Enterococcus moraviensis (type strain CCM 4856T = LMG 19486T) are proposed for the two hitherto undescribed species. The type strains and reference cultures have been deposited in the Czech Collection of Microorganisms (CCM), Masaryk University, Brno, Czech Republic, and in the BCCM/LMG Culture Collection, Ghent University, Belgium.

Base Composition↗

PubMed1991

Separation of the poly(glycerophosphate) lipoteichoic acids of Enterococcus faecalis Kiel 27738, Enterococcus hirae ATCC 9790 and Leuconostoc mesenteroides DSM 20343 into molecular species by affinity chromatography on concanavalin A.

This study shows for the first time microheterogeneity of 1,3-linked poly(glycerophosphate) lipoteichoic acids. The lipoteichoic acids investigated were those of Enterococcus faecalis Kiel 27738 (I), Enterococcus hirae (Streptococcus faecium) ATCC 9790 (II), and Leuconostoc mesenteroides DMS 20343 (III). Lipoteichoic acids II and III are partially substituted by mono-, di-, tri-, and tetra-alpha-D-glucopyranosyl residues with (1----2) interglycosidic linkages. Lipoteichoic acid I is substituted with alpha-kojibiosyl residues only. Lipoteichoic acids I and III additionally carry D-alanine ester. Lipoteichoic acids were separated on columns of concanavalin-A-Sepharose according to their increasing number of glycosyl substituents per chain. It was evident that all molecular species are usually glycosylated and that alanine ester and glycosyl residues occur on the same chains. The chain lengths of lipoteichoic acid I and II vary between 9-40 glycerophosphate residues, whereas those of lipoteichoic acid III appear to be uniform (33 +/- 2 residues). Molecular species differ in the extent of glycosylation but their content of alanyl residues is fairly constant. All lipoteichoic acids contain a small fraction (5-15%) different in composition from the bulk and most likely reflecting an early stage of biosynthesis. Two procedures for chain length determination of poly(glycerophosphate) lipoteichoic acids are described.

Chromatography, Affinity↗

PubMed2001

Evaluation of ribotyping for characterization and identification of Enterococcus haemoperoxidus and Enterococcus moraviensis strains.

Seven Enterococcus moraviensis and 16 Enterococcus haemoperoxidus as well as nine reference cultures of other enterococcal species obtained from the Czech Collection of Microorganisms were characterized using ribotyping with EcoRI and HindIII in the present work. The ribopatterns obtained by both restriction enzymes clearly distinguished all E. moraviensis and E. haemoperoxidus strains from the other enterococci (E. faecalis, E. faecium, E. avium, E. raffinosus, E. pseudoavium, E. malodoratus) and they differentiated both species from each other as well. Although all strains were isolated from different sampling sites, many strains shared the same band patterns. E. moraviensis formed four ribogroups using EcoRI and two ribogroups using HindIII restriction enzyme. E. haemoperoxidus gave six different patterns with EcoRI and five using the HindIII restriction enzyme.

DNA, Bacterial↗

PubMed1990

[The conjugative transfer of beta-hemolysin plasmid in Enterococcus faecalis to Enterococcus faecium].

The conjugative transfer by using a filter mating method in 109 cases of combinations between 20 strains of beta-hemolytic Enterococcus faecalis and 28 strains of alpha-hemolytic Enterococcus faecium was tried. A stable transconjugation was observed in two cases: from E. faecalis No. 170 to E. faecium No. 49 and from E. faecalis No. 500 to E. faecium No. 48. From the results, it was proved that the beta-hemolysin plasmid of E. faecalis is transferred by conjugation to E. faecium. The virulence (LD50) of E. faecium No. 17049, No. 50048 (heterogeneous transconjugant) and E. faecalis No. 17067, No. 50067 (homologous transconjugant) in mice was compared with their parent strains. The virulence of E. faecalis transconjugants was more marked than that of the recipients. However, the virulence of E. faecium transconjugants was not enhanced. This fact suggests that, only in E. faecalis, does beta-hemolysin play a role in its pathogenicity in mice. beta-Hemolysin in E. faecium transconjugants does not participate in pathogenicity in mice. It may be due to the fact that it takes more time to cause beta-hemolysis on blood agar plate or beta-hemolysin production in B-YEG broth by E. faecium transconjugants than by E. faecalis transconjugants.

Animals↗

PubMed1990

Mechanism of resistance to vancomycin in Enterococcus faecium D366 and Enterococcus faecalis A256.

The role of the glycopeptide-inducible proteins of Enterococcus faecium D366 (39.5 kilodaltons) and Enterococcus faecalis A256 (39 kilodaltons) in the mechanism of resistance to vancomycin and teicoplanin was examined. Crude cell walls from noninduced cells or from induced cells treated with sodium dodecyl sulfate to remove the inducible proteins were shown to bind vancomycin, in contrast to cell walls containing the cytoplasmic membrane-associated induced proteins, which did not bind vancomycin. Cytoplasmic membranes from vancomycin-induced cells did not inactivate (bind) vancomycin or teicoplanin, but they could protect the glycopeptides from being bound to the synthetic pentapeptide. This protection could be competitively abolished by D-alanyl-D-alanine. A decrease in glycopeptide binding to the pentapeptide was observed in a time-dependent fashion after treatment of the pentapeptide with the cytoplasmic membranes from induced cells. We hypothesize that the inducible proteins are responsible for glycopeptide resistance due to the binding to, and subsequent enzymatic modification of, the pentapeptide precursor of peptidoglycan, which is considered to be the natural target of glycopeptides.

Amino Acid Sequence↗

PubMed1994

Emergence of high-level resistance to glycopeptides in Enterococcus gallinarum and Enterococcus casseliflavus.

Enterococcus gallinarum BM4231 and Enterococcus casseliflavus BM4232, isolated from the feces of a patient under oral therapy with vancomycin, were resistant to high levels of vancomycin (MICs of > 256 micrograms/ml) and teicoplanin (MICs of 128 and 64 micrograms/ml, respectively). This phenotype is new for these bacterial species that are naturally resistant to low levels of vancomycin and appears to be due to in vivo acquisition of plasmid pIP218 carrying the vanA gene cluster.

Anti-Bacterial Agents↗

PubMed2006

Rapid identification of Enterococcus hirae and Enterococcus durans by PCR and detection of a homologue of the E. hirae mur-2 Gene in E. durans.

During an evaluation of PCR for identification of isolates of Enterococcus hirae, a homologue with 82% identity to E. hirae mur-2 was identified in Enterococcus durans and was named mur-2(ed). PCR using primers for two genes (copY and murG) of E. hirae strains showed amplification with E. hirae strains only. PCR (under high-stringency conditions) with primers for the mur-2(ed) gene gave the expected amplification product only with E. durans strains. A combination of murG and mur-2(ed) primers in a multiplex PCR assay differentiated E. hirae from E. durans in all cases. PCR using these primers appears to be a rapid alternative for identification of E. hirae and E. durans isolates.

Bacterial Outer Membrane Proteins↗

PubMed1990

Efficient electrotransformation of Enterococcus hirae with a new Enterococcus-Escherichia coli shuttle vector.

In the present study, an Enterococcus-Escherichia coli shuttle vector, pC3, was constructed that allows efficient transformation by electroporation of Enterococcus hirae ATCC9790. 5 x 10(6) transformants per microgram of plasmid DNA were obtained, using a commercial capacitor discharge device with an improved circuitry and a home-made electrode assembly, delivering pulses of 24 kV/cm across the cell suspension. The transformants were stable without selective pressure and plasmid DNA reisolated from transformed cells displayed no alterations in restriction enzyme analysis. Chromosomal DNA from E coli or E hirae, carried by pC3, was stably maintained in E hirae, making cloning and genetic manipulation in this organism feasible.

DNA, Bacterial↗

PubMed1991

Enterococcus dispar sp. nov. a new Enterococcus species from human sources.

The partial 16S rRNA sequences of two unknown human enterococcal isolates were determined by reverse transcription in an attempt to clarify their taxonomic position. The sequence data indicate that they belong to a hitherto unknown species of Enterococcus, for which the name Enterococcus dispar sp. nov. is proposed. The type strain is NCIMB 13000.

Base Sequence↗

PubMed1994

Modification of peptidoglycan precursors is a common feature of the low-level vancomycin-resistant VANB-type Enterococcus D366 and of the naturally glycopeptide-resistant species Lactobacillus casei, Pediococcus pentosaceus, Leuconostoc mesenteroides, and Enterococcus gallinarum.

The biochemical basis for the acquired or natural resistance of various gram-positive organisms to glycopeptides was studied by high-pressure liquid chromatographic analysis of their peptidoglycan UDP-MurNAc-peptide precursors. In all cases, resistance was correlated with partial or complete replacement of the C-terminal D-Ala-D-Ala-containing UDP-MurNAc-pentapeptide by a new precursor with a modified C terminus. Nuclear magnetic resonance analysis by sequential assignment showed that the new precursor encountered in Enterococcus faecium D366, a strain belonging to the VANB class, which expresses low-level resistance to vancomycin, was UDP-MurNAc-L-Ala-gamma-D-Glu-L-Lys-D-Ala-D-lactate, identical to that previously found in the VANA class, which expresses high-level resistance to vancomycin. High-pressure liquid chromatographic analyses, composition determinations, and digestion by R39 D,D-carboxypeptidase demonstrated the exclusive presence of the new precursor in Lactobacillus casei and Pediococcus pentosaceus, which are naturally highly resistant to glycopeptides. The low-level natural resistance of Enterococcus gallinarum to vancomycin was found to be associated with the synthesis of a new precursor identified as a UDP-MurNAc-pentapeptide containing a C-terminal D-serine. The distinction between low and high levels of resistance to glycopeptides appeared also to depend on the presence or absence of a substantial residual pool of a D-Ala-D-Ala-containing UDP-MurNAc-pentapeptide.

Amino Acid Sequence↗

PubMed1999

Structure of an antigenic teichoic acid shared by clinical isolates of Enterococcus faecalis and vancomycin-resistant Enterococcus faecium.

A shared antigenic teichoic acid, previously found to be a surface capsule-like polysaccharide, was isolated from clinical isolates of Enterococcus faecalis and vancomycin-resistant E. faecium. It was composed of glucose, glycerol, and phosphate as determined by chemical and GC-MS analysis. The repeating-unit structure was elucidated by a series of 1H, 13C, and 31P NMR spectroscopy to be the following: [formula: see text]

Antigens, Bacterial↗

PubMed2000

Comparison of antimicrobial resistance phenotypes and resistance genes in Enterococcus faecalis and Enterococcus faecium from humans in the community, broilers, and pigs in Denmark.

Enterococcus faecalis and E. faecium isolated from humans in the community (98 and 65 isolates), broilers (126 and 122), and pigs (102 and 88) during 1998 were tested for susceptibility to 12 different antimicrobial agents and for the presence of selected genes encoding resistance using PCR. Furthermore, the presence of vancomycin resistant enterococci was examined in 38 human stool samples using selective enrichment. Widespread resistance to chloramphenicol, macrolides, kanamycin, streptomycin, and tetracycline was found among isolates from all three sources. All E. faecium isolates from humans and pigs were susceptible to avilamycin, whereas 35% of isolates from broilers were resistant. All E. faecium isolates from humans were susceptible to vancomycin, whereas 10% and 17% of isolates from broilers and pigs, respectively, were resistant. A vancomycin resistant E. faecium isolate was found in one of the 38 human fecal samples examined using selective enrichment. All vancomycin resistant isolates contained the vanA gene, all chloramphenicol resistant isolates the cat(pIP501) gene, and all five gentamicin resistant isolates the aac6-aph2 gene. Sixty-one (85%) of 72 erythromycin resistant E. faecalis examined and 57 (90%) of 63 erythromycin resistant E. faecium isolates examined contained ermB. Forty (91%) of the kanamycin resistant E. faecalis and 18 (72%) of the kanamycin resistant E. faecium isolates contained aphA3. The tet(M) gene was found in 95% of the tetracycline resistant E. faecalis and E. faecium isolates of human and animal origin, examined. tet(K) was not observed, whereas tet(L) was detected in 17% of tetracycline resistant E. faecalis isolates and in 16% of the E. faecium isolates. tet(O) was not detected in any of the isolates from pigs, but was observed in 38% of E. faecalis isolates from broilers, in two E. faecalis isolates from humans and in three E. faecium isolates from broilers. tet(S) was not detected among isolates from animals, but was observed in 31% of E. faecalis and one E. faecium isolate from humans. This study showed a frequent occurrence of antimicrobial resistance and the presence of selected resistance genes in E. faecalis and E. faecium isolated from humans, broilers and pigs. Differences in the occurrence of resistance and tetracycline resistance genes were observed among isolates from the different sources. However, similar resistance patterns and resistance genes were detected frequently indicating that transmission of resistant enterococci or resistance genes takes place between humans, broilers, and pigs.

Animals↗

PubMed2000

Streptogramin resistance and shared pulsed-field gel electrophoresis patterns in vanA-containing Enterococcus faecium and Enterococcus hirae isolated from humans and animals in Spain.

The present study was performed to determine if any of the 45 vanA-containing Enterococcus faecium or 18 vanA-containing E. hirae strains were shared by chickens (32 E. faecium/l7 E. hirae) and humans (13 E. faecium/1 E. hirae) using pulsed field gel electrophoresis (PFGE) and to study quinupristin-dalfopristin (Q-D) resistance. Seven of the 45 E. faecium isolates (from 2 outpatients and from 5 poultry products) were resistant to Q-D (MIC > or = 16 microg/ml); one strain was shown to have satA by PCR and sequencing and, in the other six isolates, the recently described satG gene was demonstrated. Six different PFGE patterns were detected among the 7 Q-D E. faecium-resistant isolates. None of the E. hirae isolates showed Q-D resistance. Among the 45 vanA -containing E. faecium strains, 25 unrelated clones were found by PFGE with highly diverse patterns and an indistinguishable PFGE pattern was observed in vanA-containing E. faecium strains from two humans and two poultry products. A single PFGE pattern was detected in 17 of 18 vanA-containing E. hirae isolates, obtained from one human and 16 chicken samples. Based on the presence of indistinguishable PFGE patterns among VR E. faecium and E. hirae from humans and chickens, we conclude that horizontal transfer of these strains could occur between both groups.

Acetyltransferases↗

PubMed2006

Prevalence of aminoglycoside-modifying enzymes genes among isolates of Enterococcus faecalis and Enterococcus faecium in Iran.

Disks containing 120 microg of gentamicin were used to detect high-level gentamicin-resistant phenotype (HLGR) among isolates of Enterococcus faecalis (n = 79) and E. faecium (n = 35). These isolates were collected from three hospitals in Tehran during 2002-2004. The macrobroth dilution assay was then used to determine the minimum inhibitory concentration (MIC) of gentamicin. The susceptibility of isolates against amikacin, netilmicin, tobramycin, and kanamycin were also determined by Kirby-Bauer method. All isolates were subjected to polymerase chain reaction (PCR) assays targeting aminoglycoside modifying enzyme (AMEs) genes including aac(6 ')-aph(2 "), aph(2 ")-Ib, aph(2 ")-Ic, aph(2 ")-Ia, aph(2 ")-Id, aph(3 ')-IIIa, and ant(4 ')-Ia. Fifty-nine isolates (52%) showed HLGR phenotype. All isolates with HLGR phenotype and those showing 64 < MIC < 500 microg/ml contained aac(6 ')-aph(2 "). The aph(3 ')-IIIa was found in 61% of the isolates with HLGR phenotypes and in 65% of isolates with MIC < 500. Coexistence of aac(6 ')-aph(2 ") and aph(3 ')-IIIa gene among HLGR isolates of E. faecalis and E. faecium were 60% and 65%, respectively. The gene aph(2 ")-Ic was amplified in two isolates of E. faecium. The results of PCR for aph(2 ")-Id, ant(4 ')-Ia and aph(2 ")-Ib genes were negative. The aac(6 ')-aph(2 ") was the most frequent gene encoding resistance to gentamicin and other aminoglycosides followed by aph(3 ')-IIIa. Isolates lacking these genes were susceptible to all aminoglyocosides tested in this study.

Aminoglycosides↗

PubMed2006

Comparison of testing methods for detection of decreased linezolid susceptibility due to G2576T mutation of the 23S rRNA gene in Enterococcus faecium and Enterococcus faecalis.

E-test, Vitek 2, MicroScan, agar dilution, and disk diffusion were compared for detection of decreased linezolid susceptibility due to 23S rRNA gene G2576T mutation among 32 clinical Enterococcus strains initially reported as intermediate or resistant by E-test alone or Vitek 2 confirmed by E-test. Agar and broth dilution methods were in concordance with PCR detection of the mutation, and disk diffusion was somewhat less sensitive but equally specific.

Acetamides↗