Evaluation of antimicrobial and antiadherent properties of copper sulphate (Cu2SO4) and monoterpenes against Lactobacillus acidophilus and Streptococcus mutans

Abstract

The aim of this study was to evaluate the antimicrobial activity and antibiofilm properties of copper sulfate (Cu₂SO₄) in association with terpenes against L. acidophilus and S. mutans strains. First, the minimum inhibitory concentration (MIC) was determined using resazurin as indicator of cellular metabolism. Synergic or antagonic effects were determined by the checkerboard method, and the inhibition of biofilm formation was determined by reduction on bacterial count. Results demonstrated that Cu₂SO₄ had a better antimicrobial activity than the terpenes studied, with MIC of 50 μg/mL and 100 μg/mL against L. acidophilus and S. mutans, respectively. Regardless of this antimicrobial activity, Cu₂SO₄ alone lacks good inhibition properties in biofilm formation. A synergistic effect was observed with geraniol for both reduction in biofilm formation and antimicrobial activity. The present study highlights the antimicrobial activity of Cu₂SO₄ against microorganisms related to caries development, and that its combination with terpene compounds can be an effective alternative for the control of these etiological agents.