title: Difference in time to positivity of hub-blood versus nonhub-blood cultures is not useful for the diagnosis of catheter-related bloodstream infection in critically ill patients.
abstract: OBJECTIVE
  The differential time to positivity (DTTP), defined as the difference in time necessary for the blood cultures taken by a peripheral puncture and through the catheter to become positive has been suggested to be useful in differentiating between catheter-related bloodstream infection (CR-BSI) and other sources of bacteremia. A DTTP of >120 mins was found predominantly in CR-BSI. The objective of our study was to investigate whether DTTP is useful for the diagnosis of CR-BSI in a medical-surgical intensive care unit.
  
  
  METHODS
  Prospective clinical study.
  
  
  METHODS
  A 60-bed medical-surgical intensive care unit of a university hospital.
  
  
  METHODS
  One hundred consecutive adult patients from whom catheter(s) were to be removed for suspected CR-BSI were studied.
  
  
  METHODS
  A blood culture (using aerobic and anaerobic culture bottles) was first taken from a new puncture site. Next, a blood culture was taken through every intravascular catheter in place.
  
  
  RESULTS
  DTTP was calculated using the automated BacT/Alert blood culture system. Three patients had CR-BSI and nine patients had noncatheter-related bacteremia. Five patients had catheter-related sepsis without proven bacteremia. There was no significant difference in median DTTP between patients with CR-BSI and noncatheter-related bacteremia (2.1 hrs and 3.3 hrs, respectively; p =.6). Moreover, catheter-related sepsis in patients without bacteremia could not be detected using DTTP.
  
  
  CONCLUSIONS
  DTTP seems not to be useful for the diagnosis of CR-BSI in a medical-surgical intensive care unit.
authors.affiliation: Department of Internal Medicine, University Hospital Leuven, Leuven, Belgium.
authors.forename: B J
authors.initials: BJ
authors.lastname: Rijnders
authors.forename: C
authors.initials: C
authors.lastname: Verwaest
authors.forename: W E
authors.initials: WE
authors.lastname: Peetermans
authors.forename: A
authors.initials: A
authors.lastname: Wilmer
authors.forename: S
authors.initials: S
authors.lastname: Vandecasteele
authors.forename: J
authors.initials: J
authors.lastname: Van Eldere
authors.forename: E
authors.initials: E
authors.lastname: Van Wijngaerden
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D016470:Bacteremia / Q000175:diagnosis* / Q000209:etiology; D001800:Blood Specimen Collection / Q000379:methods*; D002405:Catheterization, Central Venous / Q000009:adverse effects*; D002406:Catheterization, Peripheral / Q000009:adverse effects*; D018929:Cell Culture Techniques / Q000379:methods*; D003937:Diagnosis, Differential; D006801:Humans; D007362:Intensive Care Units; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents