title: Use of tuf as a target for sequence-based identification of Gram-positive cocci of the genus Enterococcus, Streptococcus, coagulase-negative Staphylococcus, and Lactococcus.
abstract: BACKGROUND
  Accurate identification of isolates belonging to genus Enterococcus, Streptococcus, coagulase-negative Staphylococcus, and Lactococcus at the species level is necessary to provide a better understanding of their pathogenic potential, to aid in making clinical decisions, and to conduct epidemiologic investigations,especially when large blind samples must be analyzed. It is useful to simultaneously identify species in different genera using a single primer pair.
  
  
  METHODS
  We developed a primer pair based on the tuf gene (encoding elongation factor) sequence to identify 56 Gram-positive cocci isolates.
  
  
  RESULTS
  The target sequences were amplified from all 56 samples. The sequencing results and the phylogenetic tree derived from the partial tuf gene sequences identified the isolates as three enterococcal species, two lactococcal species, two staphylococcal species, and six streptococcal species, as well as eight isolates that were novel species of the genus Streptococcus. Partial gene sequence analysis of the sodA, dnaK, and 16S RNA genes confirmed the results obtained by tuf gene sequencing.
  
  
  CONCLUSIONS
  Based on the uniform amplification of the tuf gene from all samples and the ability to identify all isolates at both the genus and species levels, we conclude that the primer pair developed in this research provides a powerful tool for identifying these organisms in clinical laboratories where large blind samples are used.
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Grazing Animal Diseases of the Ministry of Agriculture, China.
authors.forename: Xuerui
authors.initials: X
authors.lastname: Li
authors.forename: Juan
authors.initials: J
authors.lastname: Xing
authors.forename: Baoyu
authors.initials: B
authors.lastname: Li
authors.forename: Pu
authors.initials: P
authors.lastname: Wang
authors.forename: Jixing
authors.initials: J
authors.lastname: Liu
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D003030:Coagulase / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D016983:Enterococcus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D010444:Peptide Elongation Factor Tu / Q000235:genetics*; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods; D017422:Sequence Analysis, DNA; D013210:Staphylococcus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D013291:Streptococcus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D003030:Coagulase; D017931:DNA Primers; D004269:DNA, Bacterial; C095500:SodA protein, Bacteria; D013482:Superoxide Dismutase; D010444:Peptide Elongation Factor Tu