ABSTRACT
@#Abstract: Objective To screening new compounds that can inhibit the growth and biofilm formation of Staphylococcus aureus. Methods Compounds that can inhibit the growth of Staphylococcus aureus were screened from the FDA approved drug library by 96 well plates. The absorbance value of 600 nm wavelength (OD600) was measured by Microplate Reader to detect the growth of Staphylococcus aureus planktonic cells in the culture supernatant. The minimum inhibitory concentration (MIC) of ozanimod against Staphylococcus aureus clinical isolates were detected by micro broth dilution method. The inhibitory effect of sub-inhibitory concentrations of ozanimod on the biofilm formation of Staphylococcus aureus was detected by crystal violet staining. Results This study found that ozanimod could significantly inhibit the growth of Staphylococcus aureus SA113 (screening reference strain), and the MIC was 25.00 μmol/L. The MIC of ozanimod against 119 clinical isolates of Staphylococcus aureus [65 isolates of methicillin sensitive (MSSA) and 54 isolates of methicillin resistant (MRSA)] was 12.50 or 25.00 μmol/L. The MIC50 and MIC90 of ozanimod against the 119 Staphylococcus aureus isolates all were 25.00 μmol/L. This study found that 6.25, 12.50, 25.00 μmol/L of ozanimod could significantly inhibit the biofilm formation of 2 MSSA and 2 MRSA. The sub-MIC concentration of ozanimod (12.50 μmol/L) could significantly inhibit the biofilm formation of 14 MSSA and 11 MRSA, but had no inhibitory effect on the growth of planktonic cells of these Staphylococcus aureus isolates. Conclusion Ozanimod can inhibit the growth of Staphylococcus aureus, including MRSA, and has good antibacterial activity. The sub-MIC concentration of ozanimod could significantly inhibit the biofilm formation of Staphylococcus aureus.