Abstract: 【Abstract】 Objective We studied the in-vitro stability and antimicrobial activity of vancomycin solution mixed with heparin, to predict its efficacy when used in vancomycin/heparin lock manipulation to prevent catheter-related bacteremia among maintenance hemodialysis patients.  Methods Heparin was mixed with various concentrations of vancomycin, and stored at 37℃ for 0 min, 15 min, 30 min, 24 h, or 48 h. These mixtures were then examined for visual precipitation and clarity by a clarity instrument. One of the mixtures stored at 37℃ for 0 min, 15 min, 30 min, 24 h, and 48 h was assayed for the diameter of bacteriostatic circle against staphylococcus aureus (ATCC 29213), using the same vancomycin concentration in normal saline as the standard for comparison. Results Precipitates in the mixture reduced gradually with the decrease of vancomycin concentration, and disappeared completely in the mixtures containing <10 mg/ml vancomycin. The diameters of bacteriostatic circle from the mixtures containing 10 and 20 mg/ml vancomycin were similar to those from normal saline containing 10 and 20 mg/ml vancomycin, respectively (P＞0.05). In addition, the diameters of bacteriostatic circle were statistically indifferent from one mixture stored at 37℃ for various period of time. Conclusions The degree of precipitation in vancomycin solution mixed with heparin is vancomycin concentration dependent. The mixture containing 10 mg/ml vancomycin is stable with sufficient bacteriostatic activity, and can be used as the vancomycin/heparin lock solution to prevent catheter-related bacteremia, especially that due to staphylococcus aureus infection.

Key words: Hemodialysis, Catheter-related bacteremia, Vancomycin, Antibiotic/heparin locks