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Abstract: FR-PO745

Quantification of Lipoteichoic Acid, Biofilm Morphology, and Microbiology in Hemodialysis (HD) Patients with Catheters

Session Information

Category: Dialysis

  • 701 Dialysis: Hemodialysis and Frequent Dialysis

Authors

  • Pai, Amy Barton, University of Michigan, Ann Arbor, Michigan, United States
  • Yessayan, Lenar Tatios, University of Michigan, Ann Arbor, Michigan, United States
  • Heung, Michael, University of Michigan, Ann Arbor, Michigan, United States
  • Davidge, Karen N., University of Michigan, Ann Arbor, Michigan, United States
  • Dean, Michael, University of Michigan, Ann Arbor, Michigan, United States
  • Costello, Gabrielle M., University of Michigan, Ann Arbor, Michigan, United States
Background

Lipoteichoic acid (LTA) is a Gram-positive bacteria cell wall component that is shed and induces inflammation through toll-like receptor 2. Currently, there are no non-invasive approaches to assess biofilm burden within a dialysis access. The purpose of this study was to characterize LTA concentrations in HD patients with central venous catheters (CVCs) compared to arterio-venous grafts (AVGs), and arterio-venous fistulas (AVFs) and to evaluate biofilm distribution and microbiology in pulled CVCs.

Methods

Eligible patients were adults with indwelling CVC, AVG or AVF being used for HD at the time of sample collection with no concurrent treatment for infection. Venous blood samples were collected prior to dialysis initiation, at 30 minutes, 2 hours and end of treatment (EOT). Catheter aspirate was also collected. LTA concentrations were measured by ELISA. In an ongoing sub-study, catheters that were pulled by clinical decision were evaluated by scanning electron microscopy (SEM) for biofilm surface area and the tip, mid-section and hub were cultured and bacterial species determined by MALDI-TOF.

Results

LTA profiles were measured in 17 CVC, 15 AVG and 16 AVF patients. Unexpectedly, LTA was detectable in serum from all access types at baseline and increased significantly over the dialysis session at each time point measured compared to baseline (p<0.012 for all comparisons). Catheter aspirate LTA concentration significantly correlated with serum concentrations at 2 hours and EOT (r2 0.34 and 0.30, respectively p=0.02) The rate of change from baseline to EOT was highest in patients with CVCs but was not statistically significantly different from AVF and AVG. Among catheters pulled (n=4) large plaques of biofilm were observed on all sections examined by SEM. Staphylococcus sp. including epidermidis, caprae, hominis, lugdenisis were most abundant, however, Candida albicans was also cultured from some external hub and external/internal tip sections.

Conclusion

LTA was detectable in the serum of HD patients across access types and large increases during dialysis sessions were observed. Further study of the relationship of serum LTA to biofilm surface area and biomarkers of inflammation are warranted to understand the extent to which access type contributes to inflammation in HD patients.

Funding

  • Private Foundation Support