IS26 mediated antimicrobial resistance gene shuffling from the chromosome to a mosaic conjugative FII plasmid

M Oliva; R Monno; P Addabbo; G Pesole; M Scrascia; C Calia; A M Dionisi; M Chiara; D S Horner; C Manzari; C Pazzani

doi:10.1016/j.plasmid.2018.10.001

IS26 mediated antimicrobial resistance gene shuffling from the chromosome to a mosaic conjugative FII plasmid

Plasmid. 2018 Nov:100:22-30. doi: 10.1016/j.plasmid.2018.10.001. Epub 2018 Oct 16.

Authors

M Oliva¹, R Monno², P Addabbo¹, G Pesole³, M Scrascia¹, C Calia¹, A M Dionisi⁴, M Chiara⁵, D S Horner⁵, C Manzari⁶, C Pazzani⁷

Affiliations

¹ Department of Biology, University of Bari, via Orabona, 4, Bari 70125, Italy.
² Department of Basic Medical Sciences Neurosciences and Sense Organs Medical Faculty, University of Bari Piazza G. Cesare Policlinico, Bari 70124, Italy.
³ National Research Council, Institute of Biomembranes and Bioenergetics, via Amendola 165A, Bari 70125, Italy; Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, via Orabona, 4, Bari 70125, Italy.
⁴ Department of Infectious, Parasitic and Immuno-Mediated Diseases, Istituto Superiore di Sanità, Rome 00161, Italy.
⁵ Department of Biosciences, University of Milano, via Celoria 26, Milano 20131, Italy.
⁶ National Research Council, Institute of Biomembranes and Bioenergetics, via Amendola 165A, Bari 70125, Italy.
⁷ Department of Biology, University of Bari, via Orabona, 4, Bari 70125, Italy. Electronic address: carlo.pazzani@uniba.it.

PMID: 30336162
DOI: 10.1016/j.plasmid.2018.10.001

Abstract

In the present study we report the identification of a sul3-associated class 1 integron containing the dfrA12-orfF-aadA2-cmlA1-aadA1-qacH array embedded in a Tn21-derived element that is part of a conjugative FII plasmid named pST1007-1A. The plasmid was identified in the Salmonella Typhimurium strain ST1007, a member of a clinically relevant clonal MDR lineage diffuse in Italy. ST1007 exhibited resistance to ampicillin, chloramphenicol, streptomycin, sulphamethoxazole, tetracycline and trimethoprim encoded by bla_TEM-1, cmlA1, (aadA1, aadA2, strAB), (sul2, sul3), tet(B) and dfrA12 genes, respectively. Apart from pST1007-1A, ST1007 also harbours two chromosome-integrated resistance units RU1 (bla_TEM-1-sul2-strAB) and RU2 (tet(B)), flanked by IS26 elements. RU1 and RU2 were able to move as translocatable units, respectively TU1 and TU2, and integrate via IS26 mediated recombination into pST1007-1A. A family of conjugative plasmids, harbouring different sets of antimicrobial resistance genes (ARG) was then generated: pST1007-1B (dfrA12-aadA2-cmlA1-aadA1-sul3- tet(B)), pST1007-1C (dfrA12-aadA2-cmlA1-aadA1-sul3-bla_TEM-1-sul2-strAB), pST1007-1D (bla_TEM-1-sul2-strAB), pST1007-1E (tet(B)) and pST1007-1F (dfrA12-aadA2-cmlA1-aadA1-sul3- tet(B) -bla_TEM-1-sul2-strAB). pST1007-1A is also a mosaic plasmid containing two distinct DNA fragments acquired from I1 plasmids through recombination within the repA4, rfsF and repeat-3 sites. This study further highlights the role played by IS26 in intracellular ARGs shuffling. Moreover, attention has been focused on recombination hot spots that might play a key role in generating mosaic plasmids.

Keywords: IS26; Mosaic Plasmid; Multidrug resistance; Tn21-derived.

MeSH terms

Anti-Bacterial Agents / pharmacology
Chromosome Mapping
Conjugation, Genetic
DNA Replication
DNA Transposable Elements
Drug Resistance, Bacterial / genetics*
Genome, Bacterial*
Integrons*
Operon
Plasmids / chemistry*
Plasmids / metabolism
Salmonella typhimurium / drug effects
Salmonella typhimurium / genetics*
Salmonella typhimurium / metabolism

Substances

Anti-Bacterial Agents
DNA Transposable Elements