title: Long-term clonal dynamics of Enterococcus faecium strains causing bloodstream infections (1995-2015) in Spain.
abstract: To investigate the population structure of Enterococcus faecium causing bloodstream infections (BSIs) in a tertiary Spanish hospital with low glycopeptide resistance, and to enhance our knowledge of the dynamics of emergence and spread of high-risk clonal complexes.
  
  
  
  All available E. faecium causing BSIs (n = 413) in our hospital (January 1995-May 2015) were analysed for antibiotic susceptibility (CLSI), putative virulence traits (PCR, esp, hylEfm) and clonal relationship (SmaI-PFGE, MLST evaluated by goeBURST and BAPS).
  
  
  
  The increased incidence of BSIs caused by enterococci [2.3‰ of attended patients (inpatients and outpatients) in 1996 to 3.0‰ in 2014] significantly correlated with the increase in BSIs caused by E. faecium (0.33‰ of attended patients in 1996 to 1.3‰ in 2014). The BSIs Enterococcus faecalis:E. faecium ratio changed from 5:1 in 1996 to 1:1 in 2014. During the last decade an increase in E. faecium BSIs episodes in cancer patients (10.9% in 1995-2005 and 37.1% in 2006-15) was detected. Ampicillin-susceptible E. faecium (ASEfm; different STs/BAPS) and ampicillin-resistant E. faecium (AREfm; ST18/ST17-BAPS 3.3a) isolates were recovered throughout the study. Successive waves of BAPS 2.1a-AREfm (ST117, ST203 and ST80) partially replaced ASEfm and ST18-AREfm since 2006.
  
  
  
  Different AREfm clones (belonging to BAPS 2.1a and BAPS 3.3a) consistently isolated during the last decade from BSIs might be explained by a continuous and dense colonization (favouring both invasion and cross-transmission) of hospitalized patients. High-density colonization by these clones is probably enhanced in elderly patients by heavy and prolonged antibiotic exposure, particularly in oncological patients.
authors.affiliation: Microbiology Department, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain.|Unidad de Resistencia a Antibióticos y Virulencia Bacteriana asociada al Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain.|Centros de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBER-ESP), Barcelona, Spain.
authors.forename: Ana P
authors.initials: AP
authors.lastname: Tedim
authors.affiliation: Microbiology Department, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain.|Unidad de Resistencia a Antibióticos y Virulencia Bacteriana asociada al Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain.|Spanish Network for Research in Infectious Diseases (REIPI), Seville, Spain.
authors.forename: Patricia
authors.initials: P
authors.lastname: Ruíz-Garbajosa
authors.affiliation: Microbiology Department, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain.
authors.forename: Maria Concepción
authors.initials: MC
authors.lastname: Rodríguez
authors.affiliation: Microbiology Department, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Rodríguez-Baños
authors.affiliation: Microbiology Department, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain.|Unidad de Resistencia a Antibióticos y Virulencia Bacteriana asociada al Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain.|Centros de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBER-ESP), Barcelona, Spain.
authors.forename: Val F
authors.initials: VF
authors.lastname: Lanza
authors.affiliation: Microbiology Department, Laboratory Division, Hospital General de Agudos Ramos Mejía, Ciudad Autónoma de Buenos Aires, Argentina.
authors.forename: Laura
authors.initials: L
authors.lastname: Derdoy
authors.affiliation: Clinical Laboratory, Microbiology and Infectious Diseases Department, Clinica San Francisco, Quito, Ecuador.
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Cárdenas Zurita
authors.affiliation: Microbiology Department, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Loza
authors.affiliation: Microbiology Department, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain.|Spanish Network for Research in Infectious Diseases (REIPI), Seville, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Cantón
authors.affiliation: Microbiology Department, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain.|Unidad de Resistencia a Antibióticos y Virulencia Bacteriana asociada al Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain.|Centros de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBER-ESP), Barcelona, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Baquero
authors.affiliation: Microbiology Department, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain mariateresa.coque@salud.madrid.org teresacoque@gmail.com.|Unidad de Resistencia a Antibióticos y Virulencia Bacteriana asociada al Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain.|Centros de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBER-ESP), Barcelona, Spain.
authors.forename: Teresa M
authors.initials: TM
authors.lastname: Coque
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016470:Bacteremia / Q000453:epidemiology* / Q000382:microbiology*; D002648:Child; D002675:Child, Preschool; D016984:Enterococcus faecium / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D005260:Female; D014644:Genetic Variation; D016908:Gram-Positive Bacterial Infections / Q000453:epidemiology* / Q000382:microbiology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D017720:Molecular Epidemiology; D058889:Molecular Typing; D013030:Spain / Q000453:epidemiology; D062606:Tertiary Care Centers; D037521:Virulence Factors / Q000032:analysis; D055815:Young Adult
chemical_list: D037521:Virulence Factors