http://blogs.najah.edu/author/sabrinaser-2261 An-Najah Blogs :: Department of Biology and Biotechnology, Faculty of Sciences en-us Fri, 26 Apr 2024 23:01:31 IDT Fri, 26 Apr 2024 23:01:31 IDT [email protected] [email protected] http://blogs.najah.edu/staff/sabrinaser-2261/article/Molecular-identification-of-lactic-acid-bacteria-Enterococcus-Lactobacillus-and-Streptococcus-based-on-pheS-rpoA-and-atpA-multilocus-sequence-analysis-MLSAPublished Articles Molecular identification of lactic acid bacteria Enterococcus Lactobacillus and Streptococcus based on pheS rpoA and atpA multilocus sequence analysis MLSA http://blogs.najah.edu/staff/sabrinaser-2261/article/Identification-of-lactic-acid-bacteria-in-Moroccan-raw-milk-and-traditionally-fermented-skimmed-milk-lben-Published ArticlesOuadghiri M Vancanneyt M Vandamme P Naser M S Gevers D Lefebvre K Swings J and Amar M Thirty-seven samples were collected from different farms A total of 146 LAB were isolated and subjected to GTG 5-PCR analysis Comparison of the profiles with data available at the Moroccan Coordinated Collections of Micro-organisms allowed identification of 85 isolates The remaining 61 were subjected to SDS-PAGE analysis of whole cell proteins Comparison of the profiles with data available at the Belgian Coordinated Collections of Micro-organisms allowed identification of 43 isolates Several of the remaining 18 isolates exhibited identical protein electrophoretic fingerprints Therefore eight representatives of them were subjected to partial pheS gene sequencing which allowed identification of all remaining isolates In raw milk six genera were found while in lben three were found This is the first report of Leuconostoc kimchii in dairy products LAB diversity was established using a stepwise polyphasic identifi- cation approach It used the expertise of both research bodies involved in this study and proved to be cost-effective for the identification of all isolates Significance and Impact of the Study: To establish LAB diversity in Moroccan dairy products which could be a source of strains with specific properties http://blogs.najah.edu/staff/sabrinaser-2261/article/Identification-of-lactobacilli-by-pheS-and-rpoA-gene-sequence-analysesPublished ArticlesSabri M Naser Peter Dawyndt Bart Hoste Dirk Gevers Katrien Vandemeulebroecke Ilse Cleenwerck Marc Vancanneyt Jean Swings The aim of our study was to evaluate the use of the phenylalanyl-tRNA synthase alpha subunit pheS and the RNA polymerase alpha subunit rpoA partial gene sequences for species identification of Lactobacillus Two hundred and one strains representing the validly named species 98 and their subspecies 17 were examined The pheS gene sequence analysis provides an interspecies gap which normally exceeds 10 divergence and an intraspecies variation up to 3 The rpoA gene sequences revealed a somewhat lower resolution with an interspecies gap normally exceeding 5 and an intraspecies variation up to 2 The combined use of pheS and rpoA gene sequences offers a reliable identification system for nearly all Lactobacillus species The pheS and rpoA gene sequences provide a powerful tool for detection of the potential novel Lactobacillus species and synonymous taxa In conclusion pheS and rpoA gene sequences provide alternative genomic markers to 16S rRNA gene with higher discriminatory power for reliable identification of Lactobacillus species http://blogs.najah.edu/staff/sabrinaser-2261/article/Diversity-analysis-of-Lactococcus-lactis-of-dairy-and-non-dairy-isolates-with-a-novel-multilocus-sequence-analysis-Published ArticlesRademaker J LW Herbet H Starrenburg M JC Naser S M Gevers D Kelly W J Hugenholtz J Swings J and van Hylckama Vlieg J ET The diversity of a collection of 102 lactococcus isolates including 91 Lactococcus lactis isolates of dairy and nondairy origin was explored using partial small subunit rRNA gene sequence analysis and limited phenotypic analyses A subset of 89 strains of L lactis subsp cremoris and L lactis subsp lactis isolates was further analyzed by GTG5-PCR fingerprinting and a novel multilocus sequence analysis MLSA scheme Two major genomic lineages within L lactis were found The L lactis subsp cremoris type-strain-like genotype lineage included both L lactis subsp cremoris and L lactis subsp lactis isolates The other major lineage with a L lactis subsp lactis type-strain-like genotype comprised L lactis subsp lactis isolates only A novel third genomic lineage represented two L lactis subsp lactis isolates of nondairy origin The genomic lineages deviate from the subspecific classification of L lactis that is based on a few phenotypic traits only MLSA of six partial genes atpA encoding ATP synthase alpha subunit; pheS encoding phenylalanine tRNA synthetase; rpoA encoding RNA polymerase alpha chain; bcaT encoding branched chain amino acid aminotransferase; pepN encoding aminopeptidase N; and pepX encoding X-prolyl dipeptidyl peptidase revealed 363 polymorphic sites total length 1970 bases among 89 L lactis subsp cremoris and L lactis subsp lactis isolates with unique sequence types for most isolates This allowed high-resolution cluster analysis in which dairy isolates form subclusters of limited diversity within the genomic lineages The pheS DNA sequence analysis yielded two genetic groups dissimilar to the other genotyping analysis-based lineages indicating a disparate acquisition route for this gene http://blogs.najah.edu/staff/sabrinaser-2261/article/Hospital-outbreak-of-vancomycin-resistant-enterococci-caused-by-a-single-clone-of-Enterococcus-raffinosus-and-several-clones-of-Enterococcus-faeciumPublished Articles M Kawalec J Kedzierska A Gajda E Sadowy J Wegrzyn S M Naser A B Skotnicki M Gniadkowski and W Hryniewicz A mixed outbreak caused by vancomycin-resistant Enterococcus raffinosus and Enterococcus faecium carrying the vanA gene was analysed The outbreak occurred in a large hospital in Poland and affected 27 patients most of whom were colonised in three wards including the haematology unit The E raffinosus isolates had a high-level multiresistant phenotype and were initially misidentified as Enterococcus avium ; their unambiguous identification was provided by multilocus sequence analysis The molecular investigation demonstrated the clonal character of the E raffinosus outbreak and the polyclonal structure of the E faecium isolates All of the isolates carried the same Tn1546-like element containing an IS 1251-like insertion sequence located on a c 50-kb conjugative plasmid One of the E faecium clones found previously to be endemic in the hospital was probably the source of the plasmid The results of the study suggest that difficulties in identification may have led to an underestimate of the importance of E raffinosus in vancomycin-resistant enterococci VRE control strategies http://blogs.najah.edu/staff/sabrinaser-2261/article/Molecular-identification-and-diversity-of-enterococci-isolated-from-Slovak-Bryndza-cheesePublished ArticlesD Jurkovič L Križkov M Sojka A Belicov R Duinsk J Krajčovič C Snauwaert S M Naser P Vandamme M Vancanneyt Three hundred and eight presumed enterococcal isolates were recovered from Bryndza a soft sheep milk cheese The cheese samples were obtained from five different commercial distributors in Slovakia and were taken at three different seasonal intervals All isolates were identified to the species level using genotypic tools Species-specific PCR using ddl genes highlighted the predominance of Enterococcus faecium 176 isolates and assigned 50 isolates to the species Enterococcus faecalis The remaining 82 isolates were classified using repetitive element sequence-based polymerase chain reaction PCR with primer GTG5 GTG5-PCR in combination with phenylalanyl-tRNA synthase gene pheS sequence analysis and by whole-cell protein analysis SDS-PAGE These strains were identified as Enterococcus durans 59 strains Enterococcus italicus 8 strains Enterococcus casseliflavus 3 strains Enterococcus gallinarum 3 strains Enterococcus hirae 1 strain and 8 strains were members of the species Lactococcus lactis Of the seven enterococcal species isolated three of them E durans E faecalis and E faecium were present in all samples studied with E faecium as the predominant one The precise identification of enterococci in Bryndza cheese is an essential step in the process of evaluation of their functional properties which will be further studied and assessed http://blogs.najah.edu/staff/sabrinaser-2261/article/Reclassification-of-Lactobacillus-amylophilus-LMG-11400-and-NRRL-B-4435-as-Lactobacillus-amylotrophicus-spPublished ArticlesSabri M Naser Marc Vancanneyt Cindy Snauwaert Gino Vrancken Bart Hoste Luc De Vuyst Jean Swings The taxonomic position of six Lactobacillus amylophilus strains isolated from swine waste-corn fermentations was reinvestigated All strains were included in a multilocus sequence analysis MLSA study for species identification of Lactobacillus using the genes coding for the phenylalanyl-tRNA synthase alpha subunit pheS and RNA polymerase alpha subunit rpoA The pheS and rpoA partial gene sequences showed that strains LMG 11400 and NRRL B-4435 represent a separate lineage that is distantly related to the type strain of L amylophilus LMG 6900T and to three other strains of the species The MLSA data showed that the two strains LMG 11400 and NRRL B-4435 constituted a distinct cluster yielding 100 pheS and rpoA gene sequence similarities among each other The other reference strains clustered together with the type strain of L amylophilus LMG 6900T and clearly differentiated from the strains LMG 11400 and NRRL B-4435 80 and 89 pheS and rpoA gene sequence similarities respectively The 16S rRNA gene sequences of the latter two strains are 100 identical with the nearest phylogenetic neighbour L amylophilus showing only 972 16S rRNA gene sequence similarity Further polyphasic taxonomic study based on whole-cell protein fingerprinting DNA-DNA hybridization and biochemical features demonstrated that the two Lactobacillus strains represent a single novel Lactobacillus species for which the name Lactobacillus amylotrophicus sp nov is proposed The type strain is LMG 11400T = NRRL B-4436T= DSM 20534T http://blogs.najah.edu/staff/sabrinaser-2261/article/Phylogeny-and-molecular-identification-of-vibrios-based-on-multilocus-sequence-analysisPublished ArticlesF L Thompson D Gevers C C Thompson P Dawyndt S M Naser B Hoste J Swings We analysed the usefulness of rpoA recA and pyrH gene sequences for the identification of vibrios We sequenced a fragment of these loci of a collection of 208 representative strains including 192 well-documented Vibrionaceae strains and 16 presumptive Vibrio isolates associated with coral bleaching In order to determine the intraspecies variation of the three loci we included several representative strains per species The phylogenetic trees constructed with the different genetic loci were roughly in agreement with former polyphasic taxonomic studies including the 16S rRNA-based phylogeny of vibrios The families Vibrionaceae Photobacteriaceae Enterovibrionaceae and Salinivibrionaceae were all differentiated on the basis of each genetic loci Each species clearly formed separated clusters with at least 98 94 94 rpoA recA and pyrH gene sequence similarity The genus Vibrio was heterogeneous and polyphyletic with V fischeri V logei and V wodanis grouping closer to Photobacterium V halioticoli- V harveyi- V splendidus- and V tubiashii-related species formed groups within the genus Vibrio Overall the three genetic loci were more discriminatory among species than the 16S rRNA In some cases eg within V splendidus and V tubiashii group rpoA gene sequences were slightly less discriminatory than recA and pyrH In these cases the combination of several loci will yield the most robust identification We can conclude that strains of the same species will have at least 98 94 and 94 rpoA recA and pyrH gene sequence similarity respectively http://blogs.najah.edu/staff/sabrinaser-2261/article/Photobacterium-eurosenbergii-spPublished Articles F L Thompson C C Thompson S M NaserB HosteKVandemeulebroecke C Munn D Bourne J Swings Six new Vibrio-like isolates originated from different species of bleached and healthy corals in the Magnetic Islands Australia were investigated using a polyphasic approach Phylogenetic analyses based on 16S rRNA recA and rpoA gene sequences split the isolates in two new groups Strains LMG 22223T LMG 22224 LMG 22225 LMG 22226 and LMG 22227 were phylogenetic neighbours of Photobacterium leiognathi LMG 4228T 956 16S rRNA similarity while strain LMG 22228T was related to Enterovibrio norvegicus LMG 19839T 955 16S rRNA similarity The two new groups can be distinguished from closely related species on the basis of several phenotypic features including fermentation of D27 mannitol melibiose and sucrose and utilization of different compounds as carbon sources arginine dihydrolase activity nitrate reduction resistance to the vibriostatic agent 0129 presence of 15:0 iso and 17:0 iso We propose the names Photobacterium eurosenbergii sp nov the type strain is LMG 22223T mol GC of DNA is 476 and Enterovibrio coralii sp nov the type strain is LMG 22228T mol GC of DNA is 482 to accommodate these new isolates http://blogs.najah.edu/staff/sabrinaser-2261/article/Lactobacillus-cypricasei-Lawson-et-alPublished ArticlesSabri M Naser Marc Vancanney Bart Hoste Cindy Snauwaert and Jean Swings The applicability of a multilocus sequence analysis MLSA-based identification system for Lactobacilli was evaluated Two housekeeping genes that code for the phenylalanyl-tRNA synthase alpha subunit pheS and RNA polymerase alpha subunit rpoA were sequenced and analyzed for members of the Lactobacillus salivarius species group The type strains of L acidipiscis and L cypricasei were further investigated using a third gene that codes for the alpha subunit of ATP synthase atpA The MLSA data revealed high relatedness between Lactobacillus acidipiscis and Lactobacillus cypricasei with 998 - 100 pheS rpoA and atpA gene sequence similarities Comparison of the 16S rRNA gene sequences of the two taxa confirmed high relatedness between the type strains of the two species 998 16S rRNA gene sequence similarity Similar phenotypes and high DNADNA binding values in a range of 84 to 975 confirmed that L acidipiscis and L cypricasei are synonymous species Data from the present study led to the proposal that L cypricasei is a later synonym of L acidipiscishttp://blogs.najah.edu/staff/sabrinaser-2261/article/Lactobacillus-suntoryeus-Cachat-and-Priest-2005-is-a-later-synonym-of-Lactobacillus-helveticus-Published ArticlesSabri M Naser Karen E Hagen Marc Vancanneyt Ilse Cleenwerck Jean Swingsand Thomas A Tompkins Strain R0052 originating from a North American dairy starter culture was initially identified as Lactobacillus acidophilus based on phenotypic analyses However upon sequencing the 16S rRNA gene it became clear that the isolate was very highly related to Lactobacillus suntoryeus Lactobacillus helveticus and Lactobacillus gallinarum as similarities ranging from 993 to 998 were observed As an initial screening test to investigate the relatedness between strain R0052 and reference strains of L suntoryeus L helveticus and L gallinarum the partial sequences for the genes encoding the alpha subunit of ATP synthase atpA RNA polymerase alpha subunit rpoA phenylalanyl-tRNA synthase alpha subunit pheS the translational elongation factor Tu tuf a surface-layer protein slp the Hsp60 chaperonins groEL were determined and revealed high relatedness between all strains Determination of the sequence of the 16S23S rDNA internally transcribed spacer ITS revealed 983 to 100 identity among L suntoryeus and L helveticus strains SDS-PAGE of whole-cell proteins did not distinguish both species Fluorescent Amplified Fragment Length Polymorphism FAFLP could distinguish both taxa but still constituted a single cluster within L acidophilus group Finally DNA-DNA hybridization experiments between the new isolate and the reference strains of L helveticus and L suntoryeus yielded binding values above 70 and confirmed that both species are synonymous taxa http://blogs.najah.edu/staff/sabrinaser-2261/article/Reclassification-of-Lactobacillus-brevis-LMG-11494-and-LMG-11984-as-Lactobacillus-parabrevis-spPublished ArticlesMarc Vancanneyt Sabri M Naser Katrien Engelbeen Marjan De Wachter Roel Van der Meulen Ilse Cleenwerck Bart Hoste Luc De Vuyst and Jean Swings A polyphasic study revealed taxonomic heterogeneity among reference strains of the species Lactobacillus brevis Representative strains of L brevis and related taxa were genomically investigated by partial sequence analysis of the housekeeping gene encoding the alpha subunit of the phenylalanyl-tRNA synthase pheS Species-specific clusters were delineated for all taxa studied except for two L brevis strains LMG 11494 and LMG 11984T which occupied a distinct position Their phylogenetic allocation was determined using 16S rRNA gene sequence analysis and showed that both strains belong to the Lactobacillus buchneri group with nearest neighbours Lactobacillus hammesii and L brevis sequence similarities of 992 and 981 respectively The strains LMG 11494 and LMG 11984T isolated from cheese and wheat respectively yielded 999 sequence similarity among each other Further genotypic and phenotypic study including DNA-DNA hybridizations clearly demonstrated that both strains represent a single novel taxon for which the name Lactobacillus parabrevis sp nov is proposed with the type strain LMG 11984T = ATCC 53295Thttp://blogs.najah.edu/staff/sabrinaser-2261/article/Enterococcus-silesiacus-spPublished ArticlesPavel vec Marc Vancanneyt Ivo Sedlček Sabri M Naser Cindy Snauwaert Karen Lefebvre Bart Hoste and Jean Swings Three enterococci constituted two aberrant branches after numerical analysis of GTG5-PCR fingerprints: analogous patterns were found for two water isolates strains W213 and W442T and a separate position was found for an isolate from the gut of a termite strain LMG 8895T 16S rRNA gene sequence analysis classified all three strains in the Enterococcus faecalis species group Further analysis by sequence analysis of the house keeping gene encoding for phenylalanyl-tRNA synthase alpha subunit pheS and whole-cell protein analysis confirmed a distinct position for the two water isolates and the termite strain respectively Final DNA-DNA hybridization experiments and distinct phenotypic features between the strains studied and representatives of the E faecalis species group confirmed a novel species status respectively for both water isolates strains W213 and W442T and for strain LMG 8895T The names Enterococcus silesiacus sp nov with the type strain W442T = CCM 7319T = LMG 23085T and Enterococcus termitis sp nov with the type strain LMG 8895T = CCM 7300T are proposed for the new taxahttp://blogs.najah.edu/staff/sabrinaser-2261/article/Reclassification-of-Enterococcus-flavescens-Pompei-et-alPublished ArticlesSabri M Naser Marc Vancanneyt Bart Hoste Cindy Snauwaert Katrien Vandemeulebroecke Jean Swings The taxonomic relatedness between the species Enterococcus casseliflavus and Enterococcusflavescens and between Enterococcus italicus and Enterococcus saccharominimus was investigated Literature data already indicated the synonymy between E casseliflavus and Eflavescens but this observation has never been formally published Additional evidences that both taxa represent a single species were provided by comparison of the partial sequences for three housekeeping genes phenylalanyl-tRNA synthase alpha subunit pheS RNA polymerase alpha subunit rpoA and the alpha subunit of ATP synthase atpA Further genomic data derived from DNA-DNA hybridization had demonstrated that both species are synonymous For E italicus and E saccharominimus two recently described taxa a high 16S rRNA gene sequence similarity of 99 and analogous phenotypic features indicate a close taxonomic relatedness The same multilocus sequence analysis MLSA scheme for the three housekeeping genes was also applied on E italicus and E saccharominimus and indicated possible conspecificity an observation that was also confirmed by a high DNADNA binding value 78 Data from the present study led to the proposal that Eflavescens should be reclassified as E casseliflavus and that E saccharominimus should be reclassified as E italicus http://blogs.najah.edu/staff/sabrinaser-2261/article/Enterococcus-devriesei-spPublished ArticlesPavel vec Marc Vancanneyt Joanna Koort Sabri M Naser Bart Hoste Elina Vihavainen Peter Vandamme Jean Swings and Johanna Bjrkroth The taxonomic position of two bovine strains LMG 13603 and LMG 14595T assigned to the species Enterococcus raffinosus on the basis of biochemical features was reinvestigated Both reference strains and two other isolates 61 =LMG 22829 originating from charcoal broiled river lamprey and IE384 =LMG 22830 from air of a poultry slaughter by-product processing plant occupied a clearly separate position by sequence analysis of the house keeping gene phenylalanyl-tRNA synthase alpha- subunit pheS compared to the type strain of E raffinosus and all other described enterococcal species The 16S rRNA gene sequencing of strains LMG 13603 LMG 14595T 61 =LMG 22829 and IE384 =LMG 22830 confirmed their phylogenetic position in the Enterococcus avium species group with more than 99 16S rRNA gene sequence similarity to most members of the group including E raffinosus and revealed Enterococcus pseudoavium as the closest phylogenetic relative 998 999 Further phenotypic and genotypic analyses using whole cell protein electrophoresis GTG5-PCR fingerprinting ribotyping and DNA-DNA hybridization experiments demonstrated that all four strains represent a novel enterococcal species for which the name Enterococcus devriesei sp nov is proposed The type strain is LMG 14595T =CCM 7299T http://blogs.najah.edu/staff/sabrinaser-2261/article/Enterococcus-aquimarinus-spPublished ArticlesPavel vec Marc Vancanneyt Luc A Devriese Sabri M Naser Cindy Snauwaert Karen Lefebvre Bart Hoste and Jean Swings Two enterococcal strains LMG 16607T and LMG 16612 originating from seawater were analysed in a polyphasic taxonomic study Both strains assigned as Enterococcus sp in our strain collection revealed analogous protein profiles but different from all other enterococcal species 16S rRNA gene sequence analysis of one strain showed highest similarities in a range of 969 to 961 with its closest phylogenetic neighbours Enterococcus saccharolyticus Enterococcus sulfureus Enterococcus saccharominimus and Enterococcus italicus Further genomic analysis by GTG5-PCR fingerprinting and sequence analysis of the house keeping gene phenylalanyl-tRNA synthase pheS and the presence of biochemical distinct features confirmed that these two strains represent a novel enterococcal species for which the name Enterococcus aquimarinus sp nov is proposed The type strain is LMG 16607T =CCM 7283T http://blogs.najah.edu/staff/sabrinaser-2261/article/Enterococcus-canintestini-spPublished ArticlesSabri M Naser Marc Vancanneyt Evelyne De Graef Luc A Devriese Cindy Snauwaert Karen Lefebvre Bart Hoste Pavel vec Annemie Decostere Freddy Haesebrouck Jean Swings The taxonomic position of strain LMG 13590T originally isolated from dog faeces and classified as Enterococcus dispar in the BCCMLMG Bacteria Catalogue was reinvestigated This strain and twelve recent isolates from faecal samples of healthy dogs occupied a clearly separate position when investigated with multilocus sequence analysis MLSA of the genes encoding for the alpha subunit of ATP synthase atpA RNA polymerase alpha subunit rpoA and phenylalanyl-tRNA synthase pheS The 16S rRNA gene sequence of one representative strain showed highest similarities in a range of 98 to 99 with E dispar LMG 13521T Enterococcus canis 12316T and Enterococcus asini LMG 18727T A further polyphasic taxonomic study based on whole-cell protein fingerprinting DNA-DNA hybridization and biochemical features demonstrated that the thirteen enterococcal dog faecal strains represent a single novel Enterococcus species for which the name Enterococcus canintestini sp nov is proposed The type strain is LMG 13590T = CCM 7285Thttp://blogs.najah.edu/staff/sabrinaser-2261/article/Application-of-multilocus-sequence-analysis-Published ArticlesSabri M Naser Fabiano L Thompson Bart Hoste Dirk Gevers Peter Dawyndt Marc Vancanneyt Jean Swings The aim of our study was to evaluate the use of RNA polymerase alpha subunit rpoA and phenylalanyl-tRNA synthase pheS gene sequences as species identification tools for enterococci Ninety-six representative strains comprising all currently recognized Enterococcus species were examined rpoA gene sequences generated a robust classification into species groups similar to the one based on the 16S rRNA gene sequence analysis On the other hand pheS gene is a fast evolving clock even better suited for species delineation than rpoA gene but not for recognition of the species groups within Enterococcus as determined by both rpoA and 16S rRNA genes All enterococcal species were clearly differentiated on the basis of rpoA and pheS sequences Evaluation of the intraspecies variation showed that both rpoA and pheS genes had a high degree of homogeneity among strains of the same species Strains of the same enterococcal species have at least 99 rpoA and 97 pheS gene sequence similarity whereas different enterococcal species have at maximum 97 rpoA and 86 pheS gene sequence similarity We can conclude that both genes can be used as reliable tools for identification of clinical and environmental species of Enterococcus and are efficient screening methods for detection of novel species The sequence data obtained in this study was compared to the available atpA and 16S rRNA gene sequences The MLSA approach of Enterococcus provides portable highly reproducible data with lower costs for rapid identification of all enterococcal species http://blogs.najah.edu/staff/sabrinaser-2261/article/Phylogeny-and-Identification-of-Enterococci-Using-atpA-Gene-Sequence-AnalysisPublished ArticlesSabri M Naser F L Thompson B Hoste D Gevers K Vandemeulebroecke I Cleenwerck C C Thompson M Vancanneyt J Swings The relatedness among ninety-one Enterococcus strains representing all validly described species was investigated by comparing a 1102-bp fragment of atpA the gene encoding the alpha subunit of ATP synthase The relationships observed were in agreement with the phylogeny inferred from 16S rRNA gene sequence analysis However atpA gene sequences are much more discriminatory than 16S rRNA for species differentiation All species were differentiated on the basis of atpA sequences with at maximum 92 similarity Six members of the E faecium species-group E faecium E hirae E durans E villorum E mundtii and E ratti show 99 16S rRNA gene sequence similarity but only highest values of 899 atpA gene sequence similarity were observed Intraspecies sequence similarities were for all species varying between 986 to 100 atpA sequence similarity except for E faecium strains with a lower value of 963 Our data clearly show that atpA provides an alternative tool for phylogenetic study and identification of enterococci