title: Characterization and rapid control of a vancomycin-resistant Enterococcus faecium (VREF) outbreak in a renal transplant unit in Spain: The environment matters.
abstract: OBJECTIVE
  To describe a clonal outbreak due to vancomycin-resistant Enterococcus faecium (VREF) in the nephrology and renal transplant unit of a tertiary teaching hospital in Barcelona, Spain, and to highlight how active patient and environment surveillance cultures, as well as prompt and directed intervention strategies, mainly environmental, helped to successfully bring it under control.
  
  
  METHODS
  A study was conducted on patients admitted to the nephrology ward with any culture positive for VREF over a 6-month period (August 2012-January 2013). Based on the identification of a clonal link between the isolates, weekly rectal screening using swabs was implemented for all patients, as well as environmental cultures and cleaning of medical equipment and the ward. VREF isolates were identified by MicroScan and confirmed by Etest. Bacterial identification was confirmed by MALDI-TOF MS. The presence of van genes, and esp and hyl virulence genes was determined using PCR. The clonal relationship between the isolates was studied first with DiversiLab (bioMérieux), and then by PFGE-Smal and MLST. A two-tier sequence of infection control measures was implemented.
  
  
  RESULTS
  During the study period, VREF was isolated from 13 patients. All cases were colonized with no criteria for infection. VREF isolates were also extensively recovered from the environment and medical equipment. Isolates carried the vanA gene, and were multidrug-resistant, including high-level resistance (MIC >16mg/L) to vancomycin and teicoplanin. Molecular analysis showed that all VREF isolates belonged to sequence type 17 (ST17) carrying hyl virulence genes. After implementing infection control measures in a two-tier sequence, and reinforcing particularly environmental and medical equipment cleaning, no further cases were detected in the follow-up year.
  
  
  CONCLUSIONS
  A clonal outbreak of VREF-ST17 involving only colonization is reported. The prompt implementation of aggressive infection control measures in patients and the environment was effective in controlling the outbreak and avoided the potential emergence of infection among patients.
authors.affiliation: Infectious Diseases Department, Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Parc de Salut Mar, CEXS, Universitat Pompeu Fabra, Barcelona, Spain. Electronic address: sherrera@hospitaldelmar.cat.
authors.forename: Sabina
authors.initials: S
authors.lastname: Herrera
authors.affiliation: Infectious Diseases Department, Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Parc de Salut Mar, CEXS, Universitat Pompeu Fabra, Barcelona, Spain.
authors.forename: Luisa
authors.initials: L
authors.lastname: Sorlí
authors.affiliation: Nephrology and Renal Transplant Unit, Hospital del Mar, Parc de Salut Mar, Barcelona, Spain.
authors.forename: Maria Jose
authors.initials: MJ
authors.lastname: Pérez-Sáez
authors.affiliation: Microbiology Department, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain; Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: Patricia
authors.initials: P
authors.lastname: Ruiz-Garbajosa
authors.affiliation: Nephrology and Renal Transplant Unit, Hospital del Mar, Parc de Salut Mar, Barcelona, Spain.
authors.forename: Clara
authors.initials: C
authors.lastname: Barrios
authors.affiliation: Laboratori de Refèrencia de Catalunya, El Prat de Llobregat, Spain.
authors.forename: Virginia
authors.initials: V
authors.lastname: Plasencia
authors.affiliation: Infectious Diseases Department, Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Parc de Salut Mar, CEXS, Universitat Pompeu Fabra, Barcelona, Spain.
authors.forename: Milagro
authors.initials: M
authors.lastname: Montero
authors.affiliation: Service of Epidemiology and Evaluation, Hospital del Mar, Parc de Salut Mar, Barcelona, Spain.
authors.forename: Roser
authors.initials: R
authors.lastname: Terradas
authors.affiliation: Nephrology and Renal Transplant Unit, Hospital del Mar, Parc de Salut Mar, Barcelona, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Crespo
authors.affiliation: Service of Epidemiology and Evaluation, Hospital del Mar, Parc de Salut Mar, Barcelona, Spain.
authors.forename: Xavier
authors.initials: X
authors.lastname: Castells
authors.affiliation: Microbiology Department, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain; Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Cantón
authors.affiliation: Nephrology and Renal Transplant Unit, Hospital del Mar, Parc de Salut Mar, Barcelona, Spain.
authors.forename: Julio
authors.initials: J
authors.lastname: Pascual
authors.affiliation: Infectious Diseases Department, Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Parc de Salut Mar, CEXS, Universitat Pompeu Fabra, Barcelona, Spain.
authors.forename: Juan Pablo
authors.initials: JP
authors.lastname: Horcajada
mesh_terms: D000328:Adult; D000368:Aged; D003428:Cross Infection / Q000453:epidemiology* / Q000517:prevention & control*; D004196:Disease Outbreaks / Q000517:prevention & control*; D016984:Enterococcus faecium / Q000187:drug effects*; D004783:Environmental Microbiology / Q000592:standards; D005260:Female; D016908:Gram-Positive Bacterial Infections / Q000453:epidemiology* / Q000517:prevention & control*; D006757:Hospital Units; D006801:Humans; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013030:Spain / Q000453:epidemiology; D013997:Time Factors; D020713:Vancomycin Resistance
keywords: Brote; Control de infección; Enterococcus faecium; Infection control; Nosocomial; Outbreak; Renal transplantation; Trasplante renal; VREF