title: Diversity and Evolution of the Tn5801-tet(M)-Like Integrative and Conjugative Elements among Enterococcus, Streptococcus, and Staphylococcus.
abstract: This work describes the diversity and evolution of Tn5801 among enterococci, staphylococci, and streptococci based on analysis of the 5,073 genomes of these bacterial groups available in gene databases. We also examined 610 isolates of Enterococcus (from 10 countries, 1987 to 2010) for the presence of this and other known CTn-tet(M) elements due to the scarcity of data about Tn5801 among enterococci. Genome location (by ICeu-I-pulsed-field gel electrophoresis [PFGE] hybridization/integration site identification), conjugation and fitness (by standard methods), Tn5801 characterization (by long-PCR mapping/sequencing), and clonality (by PFGE/multilocus sequence typing [MLST]) were studied. Twenty-three Tn5801 variants (17 unpublished) clustered in two groups, designated "A" (25 kb; n = 14; predominant in Staphylococcus aureus) and "B" (20 kb; n = 9; predominant in Streptococcus agalactiae). The percent GC content of the common backbone suggests a streptococcal origin of Tn5801 group B, with further acquisition of a 5-kb fragment that resulted in group A. Deep sequence analysis allowed identification of variants associated with clonal lineages of S. aureus (clonal complex 8 [CC8], sequence type 239 [ST239]), S. agalactiae (CC17), Enterococcus faecium (ST17/ST18), or Enterococcus faecalis (ST8), local variants, or variants located in different species and geographical areas. All Tn5801 elements were chromosomally located upstream of the guaA gene, which serves as an integration hot spot. Transferability was demonstrated only for Tn5801 type B among E. faecalis clonal backgrounds, which eventually harbored another Tn5801 copy. The study documents early acquisition of Tn5801 by Enterococcus, Staphylococcus, and Streptococcus. Clonal waves of these pathogens seem to have contributed to the geographical spread and local evolution of the transposon. Horizontal transfer, also demonstrated, could explain the variability observed, with the isolates often containing sequences of different origins.
authors.affiliation: Servicio de Microbiología, Hospital Universitario Ramón y Cajal, Madrid, Spain CIBER Epidemiología y Salud Pública, Madrid, Spain.
authors.forename: Ricardo
authors.initials: R
authors.lastname: León-Sampedro
authors.affiliation: UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal.
authors.forename: Carla
authors.initials: C
authors.lastname: Novais
authors.affiliation: UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal.
authors.forename: Luísa
authors.initials: L
authors.lastname: Peixe
authors.affiliation: Servicio de Microbiología, Hospital Universitario Ramón y Cajal, Madrid, Spain Unidad de Resistencia a Antibióticos y Virulencia Bacteriana asociada al Consejo Superior de Investigaciones Científicas, Madrid, Spain CIBER Epidemiología y Salud Pública, Madrid, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Baquero
authors.affiliation: Servicio de Microbiología, Hospital Universitario Ramón y Cajal, Madrid, Spain Unidad de Resistencia a Antibióticos y Virulencia Bacteriana asociada al Consejo Superior de Investigaciones Científicas, Madrid, Spain CIBER Epidemiología y Salud Pública, Madrid, Spain mariateresa.coque@salud.madrid.org.
authors.forename: Teresa M
authors.identifier: http://orcid.org/0000-0002-8228-3491
authors.initials: TM
authors.lastname: Coque
mesh_terms: D001483:Base Sequence; D004251:DNA Transposable Elements / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics; D016984:Enterococcus faecium / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D014644:Genetic Variation / Q000235:genetics*; D006801:Humans; D008826:Microbial Sensitivity Tests; D017422:Sequence Analysis, DNA; D013211:Staphylococcus aureus / Q000187:drug effects / Q000235:genetics*; D013292:Streptococcus agalactiae / Q000187:drug effects / Q000235:genetics*
chemical_list: D004251:DNA Transposable Elements; D004269:DNA, Bacterial