title: Emergence of a new antibiotic resistance mechanism in India, Pakistan, and the UK: a molecular, biological, and epidemiological study.
abstract: BACKGROUND
  Gram-negative Enterobacteriaceae with resistance to carbapenem conferred by New Delhi metallo-beta-lactamase 1 (NDM-1) are potentially a major global health problem. We investigated the prevalence of NDM-1, in multidrug-resistant Enterobacteriaceae in India, Pakistan, and the UK.
  
  
  METHODS
  Enterobacteriaceae isolates were studied from two major centres in India--Chennai (south India), Haryana (north India)--and those referred to the UK's national reference laboratory. Antibiotic susceptibilities were assessed, and the presence of the carbapenem resistance gene bla(NDM-1) was established by PCR. Isolates were typed by pulsed-field gel electrophoresis of XbaI-restricted genomic DNA. Plasmids were analysed by S1 nuclease digestion and PCR typing. Case data for UK patients were reviewed for evidence of travel and recent admission to hospitals in India or Pakistan.
  
  
  RESULTS
  We identified 44 isolates with NDM-1 in Chennai, 26 in Haryana, 37 in the UK, and 73 in other sites in India and Pakistan. NDM-1 was mostly found among Escherichia coli (36) and Klebsiella pneumoniae (111), which were highly resistant to all antibiotics except to tigecycline and colistin. K pneumoniae isolates from Haryana were clonal but NDM-1 producers from the UK and Chennai were clonally diverse. Most isolates carried the NDM-1 gene on plasmids: those from UK and Chennai were readily transferable whereas those from Haryana were not conjugative. Many of the UK NDM-1 positive patients had travelled to India or Pakistan within the past year, or had links with these countries.
  
  
  CONCLUSIONS
  The potential of NDM-1 to be a worldwide public health problem is great, and co-ordinated international surveillance is needed.
authors: Department of Microbiology, Dr ALM PG IBMS, University of Madras, Chennai, India.
authors: Karthikeyan K
authors: KK
authors: Kumarasamy
authors: Mark A
authors: MA
authors: Toleman
authors: Timothy R
authors: TR
authors: Walsh
authors: Jay
authors: J
authors: Bagaria
authors: Fafhana
authors: F
authors: Butt
authors: Ravikumar
authors: R
authors: Balakrishnan
authors: Uma
authors: U
authors: Chaudhary
authors: Michel
authors: M
authors: Doumith
authors: Christian G
authors: CG
authors: Giske
authors: Seema
authors: S
authors: Irfan
authors: Padma
authors: P
authors: Krishnan
authors: Anil V
authors: AV
authors: Kumar
authors: Sunil
authors: S
authors: Maharjan
authors: Shazad
authors: S
authors: Mushtaq
authors: Tabassum
authors: T
authors: Noorie
authors: David L
authors: DL
authors: Paterson
authors: Andrew
authors: A
authors: Pearson
authors: Claire
authors: C
authors: Perry
authors: Rachel
authors: R
authors: Pike
authors: Bhargavi
authors: B
authors: Rao
authors: Ujjwayini
authors: U
authors: Ray
authors: Jayanta B
authors: JB
authors: Sarma
authors: Madhu
authors: M
authors: Sharma
authors: Elizabeth
authors: E
authors: Sheridan
authors: Mandayam A
authors: MA
authors: Thirunarayan
authors: Jane
authors: J
authors: Turton
authors: Supriya
authors: S
authors: Upadhyay
authors: Marina
authors: M
authors: Warner
authors: William
authors: W
authors: Welfare
authors: David M
authors: DM
authors: Livermore
authors: Neil
authors: N
authors: Woodford
mesh_terms: D004352:Drug Resistance, Microbial / Q000235:genetics / Q000502:physiology*; D004755:Enterobacteriaceae / Q000187:drug effects / Q000235:genetics*; D004756:Enterobacteriaceae Infections / Q000453:epidemiology*; D006801:Humans; D007194:India / Q000453:epidemiology; D010154:Pakistan / Q000453:epidemiology; D010957:Plasmids / Q000235:genetics; D016133:Polymerase Chain Reaction; D014195:Travel; D006113:United Kingdom / Q000453:epidemiology