QJM Advance Access originally published online on September 10, 2007
QJM 2007 100(10):666-667; doi:10.1093/qjmed/hcm079
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Catheter-related sepsis in dialysis patients
Sir,Dr Thomson and his colleagues are to be commended for their recent work1 which examines catheter-related-sepsis (CRS) in dialysis patients, but I have a few concerns about their analysis and a few comments about their conclusions. While they clearly note that they have evaluated risk factors for CRS such as: age, gender, length of time on renal replacement, renal diagnosis, urea reduction ratio, serum albumin, CRP and serum ferritin, I could find no mention of some previously reported traditional risk factors for sepsis, such as: low serum calcium, peripheral atherosclerosis, a previous history of bacteraemia, a recent history of hospitalization, longer catheter survival time, frequent thrombolytic catheter infusion, and local infection.2–7 Similarly, the use of surveillance cultures has been found to be of no benefit,8–9 even when the bacteria are known to be present inside the catheter for over a year.10 While many factors may be involved in our failure to prevent CRS, biofilm is thought to be a major factor.11 Biofilms are dense aggregates of surface adherent micro-organisms embedded in a polysaccharide matrix. While mankind has become very successful since the days of Pasteur in identifying and killing free-floating (planktonic) bacteria, our knowledge of, and success against, biofilm colonies remains poor. We recently found that risk factors for biofilm such as intravenous iron and heparin use during dialysis are also the most important risk factors for CRS.12 Heparin is noted to promote biofilm formation through increased cell–cell interactions known as quorum sensing,13 and probably should not be used as a lock solution between dialysis treatments.14 Intravenous iron therapy may result in non-transferrin-bound iron that may aid bacterial attachment to the catheter wall.15
Although we have long known of the increased risks for CRS in dialysis patients that Dr Thomson has investigated, prevention has been more difficult to achieve. Many years ago, we were unsuccessful in finding any benefit from silver-impregnated cuffs that had been shown useful in preventing CRS in non-dialysis patients.16 While the increased mortality seen in patients with catheters is clearly more than just infection alone, Dr Thomson is clearly correct when he urges us to increase our efforts to prevent CRS. Perhaps interventions to limit biofilm may prove successful or, as suggested in a recent work, the use of aspirin to limit CRS may prove more useful.17
Hypertension, Nephrology, Dialysis & Transplantation
Auburn University
Opelika Alabama
USA
email: hndt512{at}bellsouth.net
References
1. Thomson PC, Stirling CM, Geddes CC, Morris ST, Mactier RA. Vascular access in haemodialysis patients: a modifiable risk factor for bacteraemia and death. Q J Med (2007) 100:415–22.[Web of Science]
2. Gulati S, Sahu KM, Avula S, Sharma RK, Ayyagiri A, Pandey CM. Role of vascular access as a risk factor for infections in hemodialysis. Ren Fail (2003) 25:967–73.[CrossRef][Web of Science][Medline]
3. Teehan GS, Bahdouch D, Ruthazer R, Balakrishnan VS, Snydman DR, Jaber BL. Iron storage indices: novel predictors of bacteremia in hemodialysis patients initiating intravenous iron therapy. Clin Infect Dis (2004) 38:1090–4.[CrossRef][Web of Science][Medline]
4. Jean G, Charra B, Chazot C, Vanel T, Terrat JC, Hurot JM, Laurent G. Risk factor analysis for long-term tunneled dialysis catheter-related bacteremias. Nephron (2002) 91:399–405.[CrossRef][Web of Science][Medline]
5. Jean G. Incidence and risk factors for infections from hemodialysis catheters. Nephrologie (2001) 22:443–8.[Web of Science][Medline]
6. Abbott KC, Agodoa LY. Etiology of bacterial septicemia in chronic dialysis patients in the United States. Clin Nephrol (2001) 56:124–31.[Web of Science][Medline]
7. Tokars JI, Light P, Anderson J, Miller ER, Parrish J, Armistead N, Jarvis WR, Gehr T. A prospective study of vascular access infections at seven outpatient hemodialysis centers. Am J Kidney Dis (2001) 37:1232–40.[Web of Science][Medline]
8. Rosenbaum D, Macrae JM, Djurdjev O, Levin A, Werb R, Kiaii M. Surveillance cultures of tunneled cuffed catheter exit sites in chronic hemodialysis patients are of no benefit. Hemodial Int (2006) 10:365–70.[CrossRef][Medline]
9. Nielsen J, Kolmos HJ, Rosdahl VT. Poor value of surveillance cultures for prediction of septicaemia caused by coagulase-negative staphylococci in patients undergoing haemodialysis with central venous catheters. Scand J Infect Dis (1998) 30:569–72.[CrossRef][Web of Science][Medline]
10. Update: Delayed onset Pseudomonas fluorescens bloodstream infections after exposure to contaminated heparin flush–Michigan and South Dakota, 2005–2006. MMWR Morb Mortal Wkly Rep (2006) 55:961–3.[Medline]
11. Stewart PS, Costerton JW. Antibiotic resistance of bacteria in biofilms. Lancet (2001) 358:135–8.[CrossRef][Web of Science][Medline]
12. Diskin CJ, Stokes TJ, Dansby LM, Radcliff L, Carter TB. Is systemic heparin a risk factor for catheter related sepsis in dialysis patients? An evaluation of biofilm and traditional risk factors. Nephron Clin Pract (2007) in press.
13. Shanks RM, Donegan NP, Graber ML, Buckingham SE, Zegans ME, Cheung AL, O’Toole GA. Heparin stimulates Staphylococcus aureus biofilm formation. Infect Immun (2005) 73:4596–606.
14. Mandolfo S, Borlandelli S, Elli A. Catheter lock solutions: it's time for a change. J Vasc Access (2006) 7:99–102.[Medline]
15. Sengoelge G, Sunder-Plassmann G, Horl WH. Potential risk for infection and atherosclerosis due to iron therapy. J Ren Nutr (2005) 15:105–10.[CrossRef][Web of Science][Medline]
16. Diskin CJ, Stokes TJ. Efficacy of an attachable silver impregnated subcutaneous cuff for the prevention of catheter-associated infections in patients on chronic maintenance hemodialysis. Nephron (1995) 69:357–9.[Web of Science][Medline]
17. Sedlacek M, Gemery JM, Cheung AL, Bayer AS, Remillard BD. Aspirin treatment is associated with a significantly decreased risk of Staphylococcus aureus bacteremia in hemodialysis patients with tunneled catheters. Am J Kidney Dis (2007) 49:401–8.[CrossRef][Web of Science][Medline]
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