title: Vascular catheter colonization: surveillance based on culture of needleless connectors.
abstract: BACKGROUND
  Superficial culture has a high negative predictive value in the assessment of catheter tip colonization (CC) and catheter-related bloodstream infection (C-RBSI). However, the process of hub culture requires the hubs to be swabbed, and this carries a risk of dislodging the biofilm. At present, most catheter hubs are closed by needleless connectors (NCs) that are periodically replaced. Our objective was to compare the yield of SC (skin + hub culture) with that of skin + NC culture in the assessment of CC and C-RBSI.
  
  
  METHODS
  During 5 months, we included the patients on the Major Heart Surgery ICU when a central venous catheter (CVC) remained in place ≥7 days after insertion. SCs were taken simultaneously when the NC was withdrawn and processed by the semi-quantitative method, even when the catheter was not removed. All catheter tips were cultured. All NCs belonging to a single catheter lumen were individually flushed with 100 μl of brain-heart infusion (BHI) broth. We considered the lumen to be colonized when ≥1 NC culture from the lumen flush was positive. We collected a total of 60 catheters.
  
  
  RESULTS
  The overall CC rate was 15.0 %, and we confirmed two episodes of C-RBSI. The validity values after the comparison of SCs with skin + NC culture for prediction of CC were the following: sensitivity 66.7 % vs. 77.8 %, and negative predictive value 93.6 % vs. 93.1 %. The sensitivity and negative predictive value for prediction of C-RBSI was 100 % for both SC and skin + NC culture.
  
  
  CONCLUSIONS
  The combination of skin and flushed NC culture can be an alternative to conventional SC for ruling out CC and C-RBSI.
authors.affiliation: Cardiac Surgery Postoperative Care Unit, Hospital General Universitario Gregorio Marañón, Madrid, Spain. massus@hotmail.es.|CIBER de Enfermedades Respiratorias-CIBERES (CB06/06/0058), Madrid, Spain. massus@hotmail.es.|Hospital General Universitario "Gregorio Marañón", C/Dr. Esquerdo, 46, 28007, Madrid, Spain. massus@hotmail.es.
authors.forename: María Jesús
authors.initials: MJ
authors.lastname: Pérez-Granda
authors.affiliation: Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain. mariaguembe@hotmail.com.|Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain. mariaguembe@hotmail.com.|Hospital General Universitario "Gregorio Marañón", C/Dr. Esquerdo, 46, 28007, Madrid, Spain. mariaguembe@hotmail.com.
authors.forename: María
authors.initials: M
authors.lastname: Guembe
authors.affiliation: Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.|Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain.
authors.forename: Raquel
authors.initials: R
authors.lastname: Cruces
authors.affiliation: Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.|Medicine Department, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain.|CIBER de Enfermedades Respiratorias-CIBERES (CB06/06/0058), Madrid, Spain.
authors.forename: Emilio
authors.initials: E
authors.lastname: Bouza
mesh_terms: D000368:Aged; D055499:Catheter-Related Infections / Q000175:diagnosis* / Q000517:prevention & control; D004866:Equipment Contamination / Q000706:statistics & numerical data*; D005260:Female; D005483:Flushing / Q000401:mortality / Q000451:nursing; D006801:Humans; D007362:Intensive Care Units / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D018805:Sepsis / Q000517:prevention & control
keywords: Catheter colonization; Catheter-related bloodstream infection; Flushing; Hub culture; Needleless connectors; Superficial culture