| Title: | "Transfer dynamics of Tn6648, a composite integrative conjugative element generated by tandem accretion of Tn5801 and Tn6647 in Enterococcus faecalis" |
| Author(s): | Leon-Sampedro R; Fernandez-de-Bobadilla MD; San Millan A; Baquero F; Coque TM; |
| Address: | "Servicio de Microbiologia, Hospital Ramon y Cajal, Instituto Ramon y Cajal de Investigacion Sanitaria (IRYCIS), Madrid, Spain. Centro de Investigacion Biomedica en Red de Epidemiologia y Salud Publica (CIBER-ESP), Madrid, Spain. Unidad de Resistencia a Antibioticos y Virulencia Bacteriana asociada al Consejo Superior de Investigaciones Cientificas (CSIC), Madrid, Spain" |
| ISSN/ISBN: | 1460-2091 (Electronic) 0305-7453 (Linking) |
| Abstract: | "BACKGROUND: Tn5801 [tet(M)], a Tn916-like element with site-specific affinity for the 3' end of the housekeeping gene guaA, may integrate at different chromosomal sites. OBJECTIVES: To characterize the genetic context of Tn5801 to define its transfer dynamics and impact on the evolution of Enterococcus faecalis (Efs). METHODS: WGS (Illumina HiSeq 2500) was performed on the Efs clinical strain Ef1 and primary and secondary transconjugants of Efs strains JH2-2 [which naturally contains Tn5801.B23, an unusual variant that lacks tet(M)], OG1RF and OG1SS carrying different copies of Tn5801-like elements. The transposon structures were analysed using a range of bioinformatics tools allowing us to identify the context of Tn5801-like elements. Growth rates at different tetracycline concentrations (0.5-20 mg/L) were estimated using a Synergy HTX plate reader. RESULTS: Tn5801.B15 [tet(M), 20.3 kb] exists and can be transferred either singly or within Tn6648 (53.2 kb), a composite element that comprises Tn5801.B15 and Tn6647, a newly identified 32.8 kb transposon that contains the prgABCT operon of pheromone-responsive plasmids. These transposons are able to integrate at specific 11 nt sequences at the 3' end of guaA and at other chromosomal sites in Efs genomes, thus being able to generate tandem accretions. These events may increase the number of tet(M) copies, enhancing tetracycline resistance in the recipient strain. CONCLUSIONS: This study describes Tn6647 and Tn6648 (comprising Tn6647 and Tn5801.B15) and highlights the diversity of mechanisms for conjugative mobilization and chromosomal insertion of these elements, which can result in tandem accretion. This strategy would facilitate the adaptation of Efs clones to environmental challenges" |
| Keywords: | "Anti-Bacterial Agents/*pharmacology Biological Evolution Chromosomes, Bacterial/*genetics Computational Biology Conjugation, Genetic DNA Transposable Elements/*genetics Enterococcus faecalis/drug effects/*genetics Plasmids/genetics Tetracycline/*pharmacol;" |
| Notes: | "MedlineLeon-Sampedro, Ricardo Fernandez-de-Bobadilla, Miguel D San Millan, Alvaro Baquero, Fernando Coque, Teresa M eng Research Support, Non-U.S. Gov't England 2019/06/22 J Antimicrob Chemother. 2019 Sep 1; 74(9):2517-2523. doi: 10.1093/jac/dkz239" |
