Bloodstream Infection: An Ounce of Prevention Is a Ton of Work

Bloodstream infection (BSI) remains the most important infectious complication of vascular access and is associated with prolonged hospital stay,1-4 increased costs,1,2,4 and, in some studies, attributable mortality.1-3,5 Prevention of BSI is essential, especially in patients requiring long-term vascular access for chemotherapy, parenteral nutrition, or hemodialysis. This issue of Infection Control and Hospital Epidemiology includes several articles about BSI: two evaluate novel anti-infective lock solutions for intravascular device–related BSI,6,7 one discusses barriers to the implementation of evidence-based recommendations for prevention of intravascular device–related BSI,8 one describes the outcomes of Staphylococcus aureus BSI in patients undergoing hemodialysis,9 and one evaluates excess mortality and costs associated with candidemia.10 Recent advances in our understanding of the pathogenesis of intravascular device–related BSI have led to the development of effective strategies for prevention.11-13 For long-term devices, it has been shown that the most common route of infection is intraluminal (ie, at the time of insertion or in the days following, microorganisms contaminate the hub [and lumen] of the intravascular device when the intravascular device is inserted over a percutaneous guidewire or later manipulated). 14-16 A promising approach has involved instilling, or locking, an anti-infective solution into the device lumen to prevent colonization of the intraluminal surface by suspended planktonic-phase contaminants.17-19 In a meta-analysis of seven randomized, controlled trials, a vancomycin–heparin lock or flush solution was found to considerably reduce the risk of intravascular device–related BSI when compared with a heparin solution alone.20 There remains concern that a vancomycincontaining lock solution may promote the emergence of vancomycin-resistant organisms, although this is unlikely due to the infinitesimal quantities of vancomycin used. A surge in research exploring anti-infective lock solutions for the prevention and treatment of intravascular device–related BSI has led to the development of several new agents. Novel agents that have shown promise in case reports, pilot studies, or small clinical trials include, among others, taurolidine,21 gentamicin–citrate,22 minocycline–ethylenediaminetetraacetic acid (EDTA),23 and ethanol.24 In this issue of Infection Control and Hospital Epidemiology, Percival et al. report their findings regarding the efficacy of yet another novel lock solution, tetrasodium EDTA, for eradicating biofilms in an in vitro model system.6 They found that tetrasodium EDTA effectively eradicated (ie, no growth at the lower limit of detection) biofilms of S. epidermidis, Pseudomonas aeruginosa, Klebsiella pneumoniae, or Escherichia coli after 21 hours of lock treatment with 4 mL of a 40-mg/mL solution; eradication of biofilms of methicillin-resistant S. aureus or Candida albicans required a further 4 hours of treatment with a fresh lock solution. The study was limited by the fact that the biofilms studied were immature and lacked the complexity of in vivo biofilms and that there are no published data on the microbicidal activity of tetrasodium EDTA to make a strong case for its superiority over other lock solutions being studied. The same group of authors previously published a study of the efficacy of tetrasodium EDTA for eradication of biofilms developed in vivo and recovered from explanted catheters, which more closely approximates the clinical setting.25 Nonetheless, the results of the current study are intriguing