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Faecalis Strains (faecali + strain)
Kinds of Faecalis Strains Selected AbstractsProduction of enterolysin A by rumen Enterococcus faecalis strain and occurrence of enlA homologues among ruminal Gram-positive cocciJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2007K. Nigutova Abstract Aims:, Purification and partial characterization of an extracellular bacteriocin produced by the ruminal isolate Enterococcus faecalis II/1 and determine the frequency of occurrence of enterolysin A structural gene within the ruminal cocci. Methods and Results:, Bacteriocin produced by E. faecalis II/1 was purified to homogeneity. Purified bacteriocin exhibited a single band on sodium dodecylsulphate polyacrylamide gel electrophoresis with an apparent molecular weight of about 35 kDa. The amino acid sequence of the first 30 amino acids of purified bacteriocin was identical with the enterolysin A sequence. The DNA sequence of the nearly complete E. faecalis II/1 bacteriocin structural gene was identical to the enterolysin A gene sequence, confirming that this bacteriocin is identical to enterolysin A, a cell wall-degrading bacteriocin from E. faecalis LMG 2333. Enterolysin A structural genes were detected in approximately one-sixth of the Gram-positive ruminal cocci examined by PCR using primers targeting the enterolysin A structural gene. Conclusions:, Bacteriocin produced by E. faecalis II/1 is identical to enterolysin A. Enterolysin A structural gene homologues are frequently encountered in rumen enterococcal and streptococcal bacterial strains. Significance and Impact of the study:, This is the first evidence of a large heat-labile bacteriocin produced by rumen E. faecalis strain, enlarging the number and types of known anti-bacterial proteins produced by rumen bacteria. [source] An amino-terminal domain of Enterococcus faecalis aggregation substance is required for aggregation, bacterial internalization by epithelial cells and binding to lipoteichoic acidMOLECULAR MICROBIOLOGY, Issue 4 2004Christopher M. Waters Summary Aggregation substance (AS), a plasmid-encoded surface protein of Enterococcus faecalis, plays important roles in virulence and antibiotic resistance transfer. Previous studies have suggested that AS-mediated aggregation of enterococcal cells could involve the binding of this protein to cell wall lipoteichoic acid (LTA). Here, a method to purify an undegraded form of Asc10, the AS of the plasmid pCF10, is described. Using this purified protein, direct binding of Asc10 to purified E. faecalis LTA was demonstrated. Equivalent binding of Asc10 to LTA purified from INY3000, an E. faecalis strain that is incapable of aggregation, was also observed. Surprisingly, mutations in a previously identified aggregation domain from amino acids 473 to 683 that abolished aggregation had no effect on LTA binding. In frame deletion analysis of Asc10 was used to identify a second aggregation domain located in the N-terminus of the protein from amino acids 156 to 358. A purified Asc10 mutant protein lacking this domain showed reduced LTA binding, while a purified N-terminal fragment from amino acids 44,331 had high LTA binding. Like the previously described aggregation domain, the newly identified Asc10(156,358) aggregation domain was also required for efficient internalization of E. faecalis into HT-29 enterocytes. Thus, Asc10 possess two distinct domains required for aggregation and eukaryotic cell internalization: an N-terminal domain that promotes binding to LTA and a second domain located near the middle of the protein. [source] Bacteriophages induced from lysogenic root canal isolates of Enterococcus faecalisMOLECULAR ORAL MICROBIOLOGY, Issue 4 2009R. H. Stevens Introduction:, Bacterial viruses play crucial roles in the pathogenesis of many systemic diseases. They are known to inhabit the oral cavity, both as free virions and as prophages in lysogenic bacterial strains; however, there has been no report of bacteriophages in endodontic infections. In this study, we sought to detect, isolate, and describe temperate bacteriophages harbored by Enterococcus faecalis strains isolated from endodontic infections. Methods: Ten E. faecalis strains were isolated from root canals of teeth undergoing retreatment following unsuccessful endodontic therapy. Mitomycin C was used to induce any prophages present in the bacterial isolates. The induced phages were purified and examined using electron microscopy. The DNA extracted from one of the phage isolates was subjected to restriction endonuclease digestion and agarose electrophoresis analysis. Results:, Lysogeny was demonstrated in 4 of the 10 E. faecalis strains. Three of the lysogenic strains yielded phages exhibiting a Siphoviridae morphology, with long, non-contractile tails 130 nm in length, and spherical/icosahedral heads 41 nm in diameter. The virus induced from the fourth lysogenic E. faecalis strain had a contractile tail characteristic of Myoviridae. Restriction endonuclease analysis of NsiI and NdeI DNA fragments from one of the Siphoviridae phage isolates (phage ,Ef11) indicated a genome size of approximately 41 kbp. Conclusion:, This is the first report of lysogenic bacteria and their inducible viruses in infected root canals. [source] Investigation of the interactions between neutrophils and endodontic isolates of Enterococcus faecalisINTERNATIONAL ENDODONTIC JOURNAL, Issue 4 2010R. Sairafi Aim, The primary aim of this study was to investigate the effect of phagocytosis by neutrophils on the antimicrobial sensitivity of Enterococcus faecalis strains. A secondary aim was to determine whether carriage of a plasmid encoding aggregation substance (AS), which has been reported to increase the survival of some strains inside neutrophils, affected the antimicrobial susceptibility of E. faecalis after phagocytosis by neutrophils. Methodology, An assay was carried out to identify isolates of E. faecalis which demonstrated pheromone-responsive clumping caused by the production of aggregation substance (AS). Four E. faecalis strains grown to both logarithmic and stationary phases were exposed to sodium hypochlorite (NaOCl) and chlorhexidine gluconate (CHX) to determine the minimum inhibitory concentrations of these two agents. The antimicrobial susceptibility tests were repeated with E. faecalis strains which survived phagocytosis by neutrophils for 18 h. Results, As expected a laboratory strain of E. faecalis OG1RF which was AS negative became AS positive after introduction of the pheromone responsive plasmid pCF10 into the bacterium to give strain OG1RF(pCF10). These two strains and two endodontic isolates, E08-584 which demonstrated pheromone-responsive clumping and E08-398 which did not, were selected for further study All the test E. faecalis strains were inhibited by low concentrations of sodium hypochlorite (MIC range 0.02,0.3%) and chlorhexidine gluconate (MIC range 0.0004,0.004%). Bacteria recovered from inside neutrophils after 18 h following phagocytosis were susceptible to both žMIC and MIC of CHX and NaOCl. Conclusions, Aggregation substance did not appear to affect the antimicrobial susceptibility of any of the strains to CHX or NaOCl. All of the E. faecalis strains examined were capable of survival for 18 h inside the neutrophils following phagocytosis; regardless of their capacity to produce aggregation substance. In addition, all strains of E. faecalis had enhanced susceptibilities to the antimicrobial agents after residence inside neutrophils for 18 h. [source] Technological characterization of the natural lactic acid bacteria of artisanal Turkish White Pickled cheeseINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 2 2008ELIF DAGDEMIR The aim of this study was to characterize the lactic acid bacteria (LAB) isolated from White Pickled cheeses produced with traditional methods; and to improve the quality of cheesemaking with a selection of bacterial cultures from artisanal White cheeses. LAB were isolated and identified from 30 White Pickled cheese samples collected from various cities in Turkey. Also, the numbers of several microbial groups (total aerobic mesophilic bacteria, LAB, enterococci, coliforms, moulds and yeasts) of cheese samples were enumerated. Lactobacilli, lactococci and enterococci were the most abundant microbial groups. The numbers of Enterococcus and Lactobacillus isolates were higher than those of the other LAB. Enterococcus faecalis (24.43%), Enterococcus faecium (17.61%) and Lactobacillus fermentum (19.88%) isolates were the most frequently isolated species. Lactococcus strains showed the highest acidifying activity, followed by Enterococcus and Lactobacillus strains. Proteolytic activity of Enterococcus faecalis strains was higher than that of the other enterococci species, except Enterococcus avium strains. Within lactobacilli strains, the highest mean proteolytic activity was that of Lactobacillus bifermentans, Lactobacillus brevis and Lactobacillus casei strains. [source] Effect of various growth media upon survival during storage of freeze-dried Enterococcus faecalis and Enterococcus duransJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2003A.S. Carvalho Abstract Aims: The effects of three different growth media (MRS, M17 and Lee's) on survival during freeze-drying and subsequent storage of six strains of Enterococcus faecalis and two strains of E. durans were investigated. Methods and Results: Distinct Enterococcus spp. strains were grown on M17, MRS and Lee's broth, freeze-dried and stored at 20°C in air under darkness. At regular intervals throughout storage, freeze-dried samples were rehydrated and then plated on M17 agar. Conclusions: A higher survival rate during storage of dried E. durans was obtained when growth occurred in MRS. The same effect was not observed, however, for the majority of E. faecalis strains, which clearly survived better in the dried state when this organism had been grown in M17 or Lee's medium. Significance and Impact of Study: The survival of the dried Enterococcus spp. tested during storage was shown to be strain-specific and dependent on the growth medium. [source] Genotypic characterization of hospital Enterococcus faecalis strains using multiple-locus variable-number tandem-repeat analysisLETTERS IN APPLIED MICROBIOLOGY, Issue 1 2009E. Wa, ecka Abstract Aims:, The level of genetic diversity and relationships between the specific genotypes and the distribution of virulence determinants among Enterococcus faecalis strains isolated from patients hospitalized in different wards of two hospitals were investigated. Methods and Results:, Fifty-six clinical strains of E. faecalis, isolated from patients hospitalized in the period of 1999,2004 in several wards in Wroc,aw (Poland), were analysed by multiple-locus variable-number tandem-repeat analysis (MLVA). Analysis of seven genomic loci identified 40 novel genotypes among the analysed E. faecalis strains, with two major genomic groups, designated I and II, distinguished at a cut-off of 35%. With a similarity cut-off of 85·7%, the genotypes could be combined into 12 clusters (C1,C12), containing at least two isolates. The remaining 18 MLVA types were represented by a single isolate. Conclusions:, Based on the data obtained by MLVA, it was found that (i) many E. faecalis isolates recovered from patients from the wards whose location allowed the potential transmission of micro-organisms, belonged to closely related MLVA types and (ii) possible relationships between specific E. faecalis genotype and the virulence factors lipase, haemolysin and esp gene can exist. Significance and Impact of the Study:, Our study confirms that MLVA is a suitable method for the epidemiological study of E. faecalis and for the first time shows possible relationships between specific genotypes and such virulence determinants, i.e. lipase, haemolysin and esp gene. [source] Bacteriophages induced from lysogenic root canal isolates of Enterococcus faecalisMOLECULAR ORAL MICROBIOLOGY, Issue 4 2009R. H. Stevens Introduction:, Bacterial viruses play crucial roles in the pathogenesis of many systemic diseases. They are known to inhabit the oral cavity, both as free virions and as prophages in lysogenic bacterial strains; however, there has been no report of bacteriophages in endodontic infections. In this study, we sought to detect, isolate, and describe temperate bacteriophages harbored by Enterococcus faecalis strains isolated from endodontic infections. Methods: Ten E. faecalis strains were isolated from root canals of teeth undergoing retreatment following unsuccessful endodontic therapy. Mitomycin C was used to induce any prophages present in the bacterial isolates. The induced phages were purified and examined using electron microscopy. The DNA extracted from one of the phage isolates was subjected to restriction endonuclease digestion and agarose electrophoresis analysis. Results:, Lysogeny was demonstrated in 4 of the 10 E. faecalis strains. Three of the lysogenic strains yielded phages exhibiting a Siphoviridae morphology, with long, non-contractile tails 130 nm in length, and spherical/icosahedral heads 41 nm in diameter. The virus induced from the fourth lysogenic E. faecalis strain had a contractile tail characteristic of Myoviridae. Restriction endonuclease analysis of NsiI and NdeI DNA fragments from one of the Siphoviridae phage isolates (phage ,Ef11) indicated a genome size of approximately 41 kbp. Conclusion:, This is the first report of lysogenic bacteria and their inducible viruses in infected root canals. [source] Comparative activity of linezolid against staphylococci and enterococci isolated in ItalyCLINICAL MICROBIOLOGY AND INFECTION, Issue 6 2002S. Stefani The activity of linezolid, a new oxazolidinone, was tested against 862 Gram-positive cocci isolated in Italy and compared with the activities of 12 antibiotics. Overall, MIC90s for linezolid (2,4 mg/L) indicated an in vitro activity comparable to that of vancomycin in methicillin-resistant Staphylococcus aureus (4 mg/L), S. epidermidis (2 mg/L) and methicillin-susceptible strains. Enterococcus faecalis strains were susceptible to linezolid (MIC90 2,4 mg/L), glycopeptides and , -lactams. In E. faecium, only glycopeptides (MIC90 2 mg/L) and linezolid (MIC90 2 mg/L) were active. Linezolid was the only drug active against two strains of Enterococcus showing a VanA phenotype. Owing to its antibacterial profile, linezolid represents a promising drug for the treatment of Gram-positive infections. [source] |