In vitro clearance effects of gallium nitrate on biofilms of clinically isolated Staphylococcus aureus

Objective To study the effect of new type antiseptic gallium nitrate on the clearance of Staphylococcus aureus(S.aureus)biofilm,and explore new methods for suppressing bacterial biofilm formation.Methods Biofilm positive strains were screened among 14 clinically isolated S.aureus strains by crystal violet staining method,minimal inhibitory concentration(MIC)of gallium nitrate for biofilm positive strains and effect of gallium nitrate on the clearance of biofilm were measured.Results Of 14 S.aureus isolates,9 were biofilm positive strains;gallium nitrate MICs for S.aureus ATCC25923,biofilm-negative strain,and 9 biofilm positive strains were all 16μg/mL;the clearance rate of gallium nitrate for early biofilm of S.aureus was significantly higher than mature biofilm([86.53±0.96]% vs[62.54±1.53]%,t=35.699,P0.001).Conclusion Gallium nitrate can inhibit growth of S.aureus strains and clear biofilm,it can be applied in the prevention and control of S.aureus infection.