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Abstract: PO1356

Detecting the Prevalence of Bacterial Colonization on Tunneled Hemodialysis Catheters Using 16S rRNA Gene Sequencing and Scanning Electron Microscopy: Lack of Evidence for Universal Colonization

Session Information

  • Vascular Access
    October 22, 2020 | Location: On-Demand
    Abstract Time: 10:00 AM - 12:00 PM

Category: Dialysis

  • 704 Dialysis: Vascular Access


  • Onder, Ali Mirza, University of Mississippi Medical Center, Jackson, Mississippi, United States
  • Cuff, Christopher F., West Virginia University Health Sciences Center, Morgantown, West Virginia, United States
  • Billings, Anthony A., West Virginia University Health Sciences Center, Morgantown, West Virginia, United States
  • Onder, Songul, The University of Tennessee Health Science Center College of Medicine, Memphis, Tennessee, United States
  • King, Judy Ann, Louisiana State University Health Sciences Center Shreveport, Shreveport, Louisiana, United States

Tunneled cuffed hemodialysis catheters (TCC) are claimed to be colonized by microorganisms early after placement, increasing risk for catheter related bacteremia (CRB). Our objective was to detect the prevalence of bacterial colonization of TCC by using 16S rRNA gene sequencing (qPCR) and investigate its association with intraluminal biofilm coverage.


45 TCC were investigated; 10 were removed due to CRB and 35 were removed for non-infectious reasons. 16S rRNA qPCR technique was used to detect intraluminal bacterial colonization after scraping the intraluminal biologic material. Proximal, middle and distal TCC were evaluated by scanning electron microscopy to determine the percentage (%) of intraluminal biofilm surface area coverage (BSA). All catheters were cultured for bacterial growth following sonication.


Twenty-seven catheters were 16S rRNA qPCR (+) (60%). Eight of these catheters were removed due to CRB. 16S rRNA qPCR (-) results were associated with the absence of bacteremia (negative predictive value of 89% and Odds Ratio = 8.0). 16S rRNA qPCR (-) results were not predicted by catheter vintage or dialysis vintage. All catheter segments were covered by biofilm with a mean % BSA of 68.4 ± 26.1%. There was statistically significant difference between the % BSA of the three catheter segments (p=0.0344). The proximal catheter segments had larger % BSA compared to distal segments. The intraluminal % BSA was inversely correlated with dialysis vintage (p<0.01). There was no statistical difference for % BSA when catheters were compared according to their 16S rRNA qPCR, catheter culture, or blood culture results.


For this cohort, biofilm accumulation on TCCs was universal but bacterial colonization was not, as measured by three different methods, suggesting that biofilm may precede colonization of TCC by microorganisms. This piece of evidence may help to improve prophylactic strategies against CRB.