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Characterization of the stability and dynamics of Tn6330 in an Escherichia coli strain by nanopore long reads.
- Source :
-
Journal of Antimicrobial Chemotherapy (JAC) . Jul2019, Vol. 74 Issue 7, p1807-1811. 5p. - Publication Year :
- 2019
-
Abstract
- <bold>Background: </bold>The mcr-1 gene has been widely reported in both bacterial chromosomes and plasmids, while its stability in these genetic materials is not well understood.<bold>Objectives: </bold>Our aim was to characterize the stability and dynamics of Tn6330 elements in both a plasmid and the chromosome in a single bacterial population.<bold>Methods: </bold>Plasmid-borne and chromosomal Tn6330 were characterized by PCR, conjugation, S1-PFGE, stability assay, single-molecule long-read sequencing and bioinformatics analysis.<bold>Results: </bold>Tn6330 was simultaneously detected in both a plasmid and the chromosome of a clinical Escherichia coli strain. The plasmid was found to comprise the IncFIB replicon and a phage-like replicon, as well as two integrons that harboured various mobile elements and resistance genes including mcr-1, floR, blaTEM-1b and strAB. Both plasmid-borne and chromosomal Tn6330 transposons could be re-organized into a circular intermediate that played a role in transmission of the mcr-1 gene. Tn6330 was found to be very stable in both the plasmid and chromosome after 30 passages of 12 h with or without colistin selective pressure. The decayed structure of Tn6330 in the genuine single DNA molecules of bacterial populations, although occurring at a very low frequency, could be detected for the first time, in which Tn6330 was degraded into a single ISApl1 element.<bold>Conclusions: </bold>Long-read sequencing technology is a good tool to study the evolution and stability of genetic elements in bacteria. The ultrastability of an mcr-1-encoding element in a bacterial plasmid and chromosome renders it unlikely to be eradicated quickly by the reduced use of colistin, and factors leading to the frequent demise of Tn6330 warrant further studies. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 03057453
- Volume :
- 74
- Issue :
- 7
- Database :
- Academic Search Index
- Journal :
- Journal of Antimicrobial Chemotherapy (JAC)
- Publication Type :
- Academic Journal
- Accession number :
- 137668373
- Full Text :
- https://doi.org/10.1093/jac/dkz117