An in vitro evaluation of the antibiotic/heparin lock to sterilize central venous haemodialysis catheters

This in vitro study investigated the ability of antibiotic/heparin locks to sterilize central venous haemodialysis catheters (CVCs) inoculated with methicillin-resistant Staphylococcus epidermidis (MRSE). Isolates of MRSE were incubated in broth inside CVCs. The catheters were then drained and filled with either vancomycin/gentamicin/heparin (VGH), cefazolin/gentamicin/ heparin (CGH) or control locks for 48 h. The catheters were drained, filled with fresh broth and again incubated. The final catheter solutions were sampled and the remaining volumes filtered. The samples, filters and catheter segments were examined for growth. For two isolates, both the VGH and CGH locks sterilized the catheters. Bacterial counts of the remaining two isolates were significantly reduced by >99%, but the catheters were not sterilized after the instillation of a single-antibiotic/heparin lock.