title: Endemic and epidemic Acinetobacter baumannii clones: a twelve-year study in a tertiary care hospital.
abstract: BACKGROUND
  Nosocomial outbreaks of multidrug-resistant Acinetobacter baumannii are of worldwide concern. Using pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and multiple locus variable number tandem repeat sequence (VNTR) analysis (MLVA), the present work examines the genetic diversity of the endemic and epidemic A. baumannii clones isolated in a single hospital over a twelve-year period.
  
  
  RESULTS
  PFGE analysis of 405 A. baumannii-calcoaceticus complex isolates detected 15 A. baumannii endemic/epidemic PFGE types (EE1 to EE15) that grouped into five clusters: EE1-EE8, EE9, EE10, EE11 and EE12-EE15. The MLST sequence type (ST) distributions were: international clone II (ST-2) 60%, international clone III (ST-3) 26.7%, ST-15 6.7%, and ST-80 6.7%. MLVA-8Orsay returned 17 allelic profiles. The large (L) VNTR marker profiles were fully concordant with the detected STs, and concordant with 14 up to 15 PFGE types. Imipenem resistance was detected in five PFGE types; the prevalence of the bla OXA-58-like and bla OXA-40-like genes was 60% and 40% respectively.
  
  
  CONCLUSIONS
  PFGE proved to be a vital tool for analysis of the temporal and spatial distribution of the clones. MLST and the VNTR L-markers grouped the isolates into clonal clusters. The wide diversity of MLVA small (S)-markers, however, did not permit clustering. The present results demonstrate the persistence of several endemic PFGE types in the hospital, the involvement of some of them in outbreaks, and the inter hospital transmission of extensively drug-resistant ST-15 and ST-80.
authors.affiliation: Laboratorio de Taxonomía, Servicio de Bacteriología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda-Pozuelo km2, 28220, Madrid, Majadahonda, Spain. pvillalon@isciii.es.
authors.forename: Pilar
authors.initials: P
authors.lastname: Villalón
authors.affiliation: Laboratorio de Taxonomía, Servicio de Bacteriología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda-Pozuelo km2, 28220, Madrid, Majadahonda, Spain. svaldezate@isciii.es.
authors.forename: Sylvia
authors.initials: S
authors.lastname: Valdezate
authors.affiliation: Laboratorio de Biotecnología Hospital de Poniente El Ejido, Almería, Spain. mariateresa.cabezas@ephpo.es.
authors.forename: Teresa
authors.initials: T
authors.lastname: Cabezas
authors.affiliation: Laboratorio de Taxonomía, Servicio de Bacteriología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda-Pozuelo km2, 28220, Madrid, Majadahonda, Spain. mortega@isciii.es.
authors.forename: Montserrat
authors.initials: M
authors.lastname: Ortega
authors.affiliation: Laboratorio de Taxonomía, Servicio de Bacteriología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda-Pozuelo km2, 28220, Madrid, Majadahonda, Spain. noegarrido@isciii.es.
authors.forename: Noelia
authors.initials: N
authors.lastname: Garrido
authors.affiliation: Laboratorio de Infecciones Intrahospitalarias Servicio de Bacteriología, Centro Nacional de Microbiología Instituto de Salud Carlos III, Majadahonda, Madrid, Spain. avindel@isciii.es.
authors.forename: Ana
authors.initials: A
authors.lastname: Vindel
authors.affiliation: Laboratorio de Taxonomía, Servicio de Bacteriología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda-Pozuelo km2, 28220, Madrid, Majadahonda, Spain. mjmedina@isciii.es.
authors.forename: María J
authors.initials: MJ
authors.lastname: Medina-Pascual
authors.affiliation: Laboratorio de Taxonomía, Servicio de Bacteriología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda-Pozuelo km2, 28220, Madrid, Majadahonda, Spain. jasaez@isciii.es.
authors.forename: Juan A
authors.initials: JA
authors.lastname: Saez-Nieto
mesh_terms: D000151:Acinetobacter Infections / Q000453:epidemiology* / Q000382:microbiology*; D040981:Acinetobacter baumannii / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology*; D004269:DNA, Bacterial / Q000235:genetics; D005838:Genotype; D006801:Humans; D018598:Minisatellite Repeats; D017720:Molecular Epidemiology; D058885:Multilocus Sequence Typing; D012150:Polymorphism, Restriction Fragment Length; D062606:Tertiary Care Centers
chemical_list: D004269:DNA, Bacterial