The role of polymer surface degradation and barium sulphate release in the pathogenesis of catheter-related infection.
BACKGROUND
Susceptibility to infection and thrombosis of intravascular catheters is increased by surface irregularities, which might be prevented by coating.


METHODS
BaSO4 release from conventional haemodialysis catheters (CC) and modified catheters (MC) which had been coated with a surface-modifying additive (SMA) was assessed in vivo and in vitro. For the in vivo part, patients were randomized to receive a temporary CC or MC, with crossover after 1 week. After retrieval, catheters were examined using scanning electron microscopy to assess surface integrity, and an in vitro model of catheter exposure to the bloodstream was used to evaluate surface morphology and susceptibility to bacterial adhesion and proliferation.


RESULTS
BaSO(4) moieties covered 14.7 +/- 3.7% of the surface of unused CC. After in vivo use in 16 patients, 62.7 +/- 32.9 x 10(3) holes/mm(2) were detected, indicating BaSO(4) detachment from 3.3 +/- 1.7% of the catheter surface. No defects were observed in unused CC and in MC, whether used or unused. After incubation of four catheters (two of each type) with Staphylococcus epidermidis, the two degraded CC showed an immediate and strong bacterial growth as indicated by an increase in medium impedance of 0.512%/10 min compared to -0.021%/10 min in MC (P < 0.001).


CONCLUSIONS
Short-term exposure of CC to the bloodstream causes BaSO(4) particle release, resulting in surface irregularities predisposing to bacterial proliferation. BaSO(4) release can be prevented by SMA coating.
Verbeke
Francis
F
University Hospital Ghent-Department of Internal Medicine, Nephrology section, De Pintelaan 185, 9000 Ghent, Belgium. francis.verbeke@UGent.be
Haug
Ulrike
U
Dhondt
Annemieke
A
Beck
Werner
W
Schnell
Andrea
A
Dietrich
Ruth
R
Deppisch
Reinhold
R
Vanholder
Raymond
R
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001422:Bacterial Adhesion; D001466:Barium Sulfate / Q000378:metabolism*; D055499:Catheter-Related Infections / Q000209:etiology* / Q000473:pathology; D002408:Catheters, Indwelling; D020099:Coated Materials, Biocompatible / Q000009:adverse effects*; D004866:Equipment Contamination; D005260:Female; D006801:Humans; D007674:Kidney Diseases / Q000628:therapy; D008297:Male; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D011108:Polymers / Q000737:chemistry* / Q000378:metabolism; D006435:Renal Dialysis; D013203:Staphylococcal Infections / Q000209:etiology* / Q000473:pathology; D013212:Staphylococcus epidermidis / Q000254:growth & development*; D013499:Surface Properties; D055815:Young Adult
D000900:Anti-Bacterial Agents; D020099:Coated Materials, Biocompatible; D011108:Polymers; D001466:Barium Sulfate