Complete sequencing of an IncX3 plasmid carrying blaNDM-5 allele reveals an early stage in the dissemination of the blaNDM gene.
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Date
2015-01
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Abstract
Purpose: The aim of the present study was to perform molecular characterisation of the blaNDM plasmids and to
understand the mechanism of its spread among pathogenic bacteria. Materials and Methods: Seventy-six non-repetitive
carbapenem-resistant isolates which were collected during Nov 2011 to April 2013 from four hospitals in Chennai
were analyzed for the presence of the blaNDM gene by PCR. Further, the genetic context of the blaNDM gene was
analyzed by PCR specifi c to ISAba125 and bleMBL gene. One of the blaNDM plasmid was completely sequenced in the
Illumina HiSeq platform. Results: Twenty-three isolates consisting of 8 Escherichia coli, 8 Klebsiella pneumoniae, 3
Klebsiella oxytoca, 3 Acinetobacter baumanii and 1 Pseudomonas aeruginosa were found to carry the blaNDM gene. In
18 isolates the blaNDM gene was associated with a bleMBL gene and the ISAba125 element. The complete sequencing of
pNDM-MGR194 revealed an IncX3 replication type plasmid, with a length of 46,253 bp, an average GC content of 47%
and 59 putative ORFs. The iteron region contained the blaNDM5 gene and the bleMBL, trpF and dsbC genes downstream
and an IS5 inserted within the ISAba125 element upstream. Conclusion: This is the fi rst report where the blaNDM gene
insertion in a plasmid is not accompanied by other resistance gene determinants. These observations suggest that the
IncX3 plasmid pNDM-MGR194 is an early stage in the dissemination of the blaNDM.
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Keywords
blaNDM, ISAba125, IncX3, metallo carbapenemase
Citation
Krishnaraju M, Kamatchi C, Jha A K, Devasena N, Vennila R, Sumathi G, Vaidyanathan R. Complete sequencing of an IncX3 plasmid carrying blaNDM-5 allele reveals an early stage in the dissemination of the blaNDM gene. Indian Journal of Medical Microbiology. 2015 Jan-Mar ; 33 (1): 30-38.