title: Novel lnu(G) gene conferring resistance to lincomycin by nucleotidylation, located on Tn6260 from Enterococcus faecalis E531.
abstract: To identify a novel putative lincosamide resistance gene determinant in a swine Enterococcus faecalis E531 exhibiting a lincosamide resistance/macrolide susceptibility (L R M S ) phenotype and to determine its location and genetic environment.
  
  
  
  The whole genomic DNA of E. faecalis E531, which tested negative for the known lincosamide nucleotidyltransferase genes, was sequenced. A putative lincosamide resistance gene determinant was cloned into an Escherichia coli - E. faecalis shuttle vector (pAM401) and transformed into E. faecalis JH2-2. The MICs were determined by the microbroth dilution method. Inactivity of lincomycin was examined by UPLC-MS/MS. Inverse PCR and primer walking were used to explore the genetic environment based on the assembled sequence.
  
  
  
  A novel resistance gene, designated lnu (G), which encodes a putative lincosamide nucleotidyltransferase, was found in E. faecalis E531. The deduced Lnu(G) amino acid sequence displayed 76.0% identity to Lnu(B) in Enterococcus faecium . Both E. faecalis E531 and E. faecalis JH2-2 harbouring pAM401- lnu (G) showed a 4-fold increase in the MICs of lincomycin, compared with E. faecalis JH2-2 or E. faecalis JH2-2 harbouring empty vector pAM401 only. UPLC-MS/MS demonstrated that the Lnu(G) enzyme catalysed adenylylation of lincomycin. The genetic environment analysis revealed that the lnu (G) gene was embedded into a novel putative transposon, designated Tn 6260 , which was active.
  
  
  
  A novel lincosamide nucleotidyltransferase gene lnu (G) was identified in E. faecalis . The location of the lnu (G) gene on a mobile element Tn 6260 makes it easy to disseminate.
authors.affiliation: College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, P. R. China.
authors.forename: Xiao-Qing
authors.initials: XQ
authors.lastname: Zhu
authors.affiliation: College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, P. R. China.
authors.forename: Xiao-Ming
authors.initials: XM
authors.lastname: Wang
authors.affiliation: College of Veterinary Medicine, China Agricultural University, Beijing 100193, P. R. China.
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.affiliation: College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, P. R. China.
authors.forename: Yan-Hong
authors.initials: YH
authors.lastname: Shang
authors.affiliation: College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, P. R. China.
authors.forename: Yu-Shan
authors.initials: YS
authors.lastname: Pan
authors.affiliation: College of Veterinary Medicine, China Agricultural University, Beijing 100193, P. R. China.
authors.forename: Cong-Ming
authors.initials: CM
authors.lastname: Wu
authors.affiliation: College of Veterinary Medicine, China Agricultural University, Beijing 100193, P. R. China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Wang
authors.affiliation: College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, P. R. China.
authors.forename: Xiang-Dang
authors.initials: XD
authors.lastname: Du
authors.affiliation: College of Veterinary Medicine, China Agricultural University, Beijing 100193, P. R. China.
authors.forename: Jian-Zhong
authors.initials: JZ
authors.lastname: Shen
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004251:DNA Transposable Elements; D024881:Drug Resistance, Bacterial; D013293:Enterococcus faecalis / Q000187:drug effects* / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D016680:Genome, Bacterial; D016908:Gram-Positive Bacterial Infections / Q000662:veterinary; D008034:Lincomycin / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D009713:Nucleotidyltransferases / Q000235:genetics*; D017422:Sequence Analysis, DNA; D013552:Swine
chemical_list: D000900:Anti-Bacterial Agents; D004251:DNA Transposable Elements; D008034:Lincomycin; D009713:Nucleotidyltransferases