Effects of bone cement loaded with teicoplanin, N-acetylcysteine or their combination on Staphylococcus aureus biofilm formation: an in vitro study.

OBJECTIVES: This study aims to demonstrate the antibiofilm effects of teicoplanin alone, N-acetyl cysteine (NAC) alone, or combination of both compounds when mixed with bone cement.

MATERIALS AND METHODS: A total of four groups were formed by using six cement samples in each, prepared with bone cement having different contents in each group. Group 1 (control group): cement alone without any drugs added. Group 2: 40 g cement, 400 mg teicoplanin. Group 3: 40 g cement, 6 g NAC. Group 4: 40 g cement, 6 g NAC, 400 mg teicoplanin. All cement samples were infected with Staphylococcus aureus for 48 hours at 36.5 °C. Bacterial colonies were then counted by serial dilution method. Bacteria were counted using scanning electron microscopic (SEM) images.

RESULTS: Counts of bacteria colonies were 5.83±1.60 [mean colony forming unit (cfu) x 105±standard deviation (SD)] in group 1, 0.12±0.56 in group 2, 0.11±0.65 in group 3, and 0.01±0.001 in group 4. Significant difference was found between group 1 and all other groups (p<0.05), and between group 4 and all other groups (p<0.05). According to SEM analysis, counts of bacteria (mean±SD) were 1.88±0.45, 0.75±0.26, 0.21±0.22, and 0.13±0.25 in groups 1, 2, 3, and 4, respectively. Significant difference was found between group 1 and all other groups (p<0.05), and between group 4 and all other groups (p<0.05).

CONCLUSION: N-acetyl cysteine, teicoplanin, and their combination significantly reduced formation of biofilm compared to the control group. Also, combination of NAC and teicoplanin had the highest antibiofilm effect.