title: Emergence of Klebsiella variicola positive for NDM-9, a variant of New Delhi metallo-β-lactamase, in an urban river in South Korea.
abstract: To examine the presence of pathogenic bacteria carrying New Delhi metallo-β-lactamase in the environment and to characterize the genome structures of these strains.
  
  
  
  Phenotypic screening of antimicrobial susceptibility and WGS were conducted on three Klebsiella variicola strains possessing NDM-9 isolated from an urban river.
  
  
  
  Three carbapenem-resistant K. variicola isolated from Gwangju tributary were found to possess bla NDM-9 genes. Antimicrobial susceptibility testing indicated resistance of these strains to aminoglycosides, carbapenems, cephems, folate pathway inhibitors, fosfomycin and penicillins, but susceptibility to fluoroquinolones, phenicols, tetracyclines and miscellaneous agents. WGS revealed that the 108 kb IncFII(Y)-like plasmids carry bla NDM-9 sandwiched between IS 15 for the GJ1 strain, IS 26 for the GJ2 strain, IS 15D1 for the GJ3 strain and IS Vsa3 , and further bracketed by IS 26 and Tn AS3 along with the mercury resistance operon upstream and the class 1 integron composed of gene cassettes of aadA2 , dfrA12 and sul1 downstream. An aph(3')-Ia gene conferring resistance to aminoglycosides is located after the integrons. Chromosomally encoded bla LEN-13 , fosA , aqxA and oqxB genes, as well as plasmid-mediated bla TEM-1B and bla CTX-M-65 encoding ESBL, ant(3')-Ia and mph (A) genes, were also identified.
  
  
  
  The findings of the present study provide us with the information that NDM-9 has been spreading into the environment. Dissemination of NDM-9 in the environment has raised a health risk alarm as this variant of NDM carries MDR genes with highly transferable mobile genetic elements, increasing the possibility of resistance gene transfer among microorganisms in the environment.
authors.affiliation: School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea.
authors.forename: Doris Y W
authors.initials: DY
authors.lastname: Di
authors.affiliation: BioTechnology Institute, University of Minnesota, Saint Paul, MN 55108, USA.
authors.forename: Jeonghwan
authors.initials: J
authors.lastname: Jang
authors.affiliation: Faculty of Biotechnology, College of Applied Life Science, SARI, Jeju National University, 690-756 Jeju, Republic of Korea.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Unno
authors.affiliation: School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea.
authors.forename: Hor-Gil
authors.initials: HG
authors.lastname: Hur
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002947:Cities; D005798:Genes, Bacterial; D016680:Genome, Bacterial; D020071:Interspersed Repetitive Sequences; D007709:Klebsiella / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification*; D008826:Microbial Sensitivity Tests; D056910:Republic of Korea; D045483:Rivers / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D001618:beta-Lactamases / Q000032:analysis* / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D001618:beta-Lactamases; C552864:beta-lactamase NDM-1