To the Editor:

Recently, van Rooden et al¹ showed that three times per week urokinase rinsing reduced the incidence of central venous catheter (CVC)–related coagulase-negative staphylococci (CoNS) infections in patients with hematologic malignancies. Although infection rates are not reported as the number of infections per 1,000 CVC days,² we are concerned by the unusually high rate of catheter-related bloodstream infections (CR-BSI) reported in this study: 18% of patients in the control group developed CoNS bacteremia, despite an intermediate duration of catheterization (30 days), leading to an incidence density of about 7.7 CoNS bacteremia per 1,000 CVC days.

In patients with cancer or hematologic malignancies, lower rates of CR-BSI have been reported, as well as in high-risk populations such as critically ill patients. In a population of patients with cancer with a two-fold longer indwelling time (60 days), Hanna et al³ observed only 8% of CR-BSI due to all types of micro-organisms, of which only one third was due to CoNS. In a study of bone marrow transplant recipients,⁴ at a time when modern preventive methods were not yet widely employed, only 7% of the patients developed CoNS CR-BSI (ie, a similar rate to that reported in the urokinase group in the van Rooden study).

We wonder whether the interpretation of the reduction of infection rates reported in studies testing innovative prevention approaches might be biased due to a high prevalence rate of CR-BSI in control groups, leading to legitimate suspicion as to whether standard preventive guidelines were really applied. This point is underlined by the authors themselves, who explain that the overall prevalence of infection was reduced from 45% in their pilot study to 24.4% in the prospective study period, partly due to “better preventive measures in the overall study period.”¹ This finding is likely more spectacular than the reduction of CoNS infections obtained with urokinase.

It is noteworthy that a 25-year-old study already showed that optimum nursing care by itself was able to dramatically reduce the risk of catheter-related sepsis, making the benefit of a sophisticated method such as catheter tunneling almost seem anecdotal.⁵ Tunneling the catheter was efficient when nursing care was suboptimum (and the rates of infection unacceptably high), while rigorous aseptic care considerably reduced the infection rates of CVC, whether they were tunneled or not.

We are convinced that such sophisticated methods divert physicians from using simple and efficient prophylaxis against catheter-related infections. In the setting of critically ill patients, simple measures such as the use of full-barrier precautions during catheter insertion or the use of chlorhexidine for skin disinfection have both dramatically reduced the risk of CR-BSI.⁶ There is no doubt that a similar rigorous approach could yield outstanding results in the setting of hematologic malignancies. Sophisticated and costly methods such as antiseptic/antibiotic impregnated devices or urokinase rinsing should be reserved for units where the control of CR-BSI cannot be obtained by deploying all the aforementioned standard preventive methods.⁷

AUTHORS’ DISCLOSURES OF POTENTIAL CONFLICTS OF INTEREST

The author(s) indicated no potential conflicts of interest.