title: Identification and molecular characterisation of New Delhi metallo-β-lactamase-1 (NDM-1)- and NDM-6-producing Enterobacteriaceae from New Zealand hospitals.
abstract: The global spread of New Delhi metallo-β-lactamase (NDM) is of significant public health concern. This study sought to determine whether bla(NDM) was present in Enterobacteriaceae isolates displaying resistance to carbapenems that were submitted to the National Antibiotic Reference Laboratory, Institute of Environmental Science and Research (Porirua, New Zealand) during 2009 and 2010. Isolates were tested for the presence of β-lactamase genes and 16S rRNA methylase genes by polymerase chain reaction (PCR) and sequencing. Plasmid transfer studies were undertaken on isolates found to be harbouring bla(NDM). Molecular typing was performed by multilocus sequence typing (MLST). The bla(NDM-1) gene was identified in four Enterobacteriaceae isolates (two Escherichia coli, one Klebsiella pneumoniae and one Proteus mirabilis) from four patients in New Zealand hospitals in 2009 and 2010. In addition, the bla(NDM-6) gene, which differed from bla(NDM-1) by a point mutation at position 698 (C→T), was also identified in an E. coli isolate from the same patient who harboured the bla(NDM-1)-positive P. mirabilis. All four patients had recently been hospitalised or received health care in India. Four of the isolates also produced a CTX-M-15 extended-spectrum β-lactamase and/or plasmid-mediated AmpC β-lactamase, and all five isolates harboured the plasmid-mediated 16S rRNA methylase rmtC gene. The E. coli types were diverse by MLST, and the K. pneumoniae isolate belonged to the internationally disseminated sequence type 11 (ST11) clone. These findings further illustrate the diversity of phenotypic and genotypic features found in association with bla(NDM), in addition to documenting the international spread of this resistance mechanism, notably into a country with historically low rates of antimicrobial resistance.
authors.affiliation: Department of Clinical Microbiology, Auckland District Health Board, Park Road, Grafton, Auckland, New Zealand. dwilliamson@adhb.govt.nz
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Williamson
authors.forename: Hanna E
authors.initials: HE
authors.lastname: Sidjabat
authors.forename: Joshua T
authors.initials: JT
authors.lastname: Freeman
authors.forename: Sally A
authors.initials: SA
authors.lastname: Roberts
authors.forename: Anna
authors.initials: A
authors.lastname: Silvey
authors.forename: Rosemary
authors.initials: R
authors.lastname: Woodhouse
authors.forename: Eilidh
authors.initials: E
authors.lastname: Mowat
authors.forename: Kristin
authors.initials: K
authors.lastname: Dyet
authors.forename: David L
authors.initials: DL
authors.lastname: Paterson
authors.forename: Timothy
authors.initials: T
authors.lastname: Blackmore
authors.forename: Andrew
authors.initials: A
authors.lastname: Burns
authors.forename: Helen
authors.initials: H
authors.lastname: Heffernan
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology; D004269:DNA, Bacterial; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D004755:Enterobacteriaceae / Q000145:classification* / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D004756:Enterobacteriaceae Infections / Q000453:epidemiology* / Q000382:microbiology; D006801:Humans; D008780:Methyltransferases / Q000235:genetics; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D058885:Multilocus Sequence Typing; D009520:New Zealand / Q000453:epidemiology; D017422:Sequence Analysis, DNA; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D008780:Methyltransferases; D001618:beta-Lactamases; C552864:beta-lactamase NDM-1; C063912:carbapenemase