Sanchen powder extract combined with vancomycin against methicillin-resistant Staphylococcus aureus

ObjectiveTo explore the effects of the extract of Sanchen powder (ESCP) combined with vancomycin on methicillin-resistant Staphylococcus aureus (MRSA) planktonic cells, biofilms, and virulence factors.MethodsThe herbs in Sanchen powder (SCP) were extracted separately with 50% ethanol. Then, the content of hydroxysafflower yellow A (HSYA) and cholic acid in the extract of artificial cattle bezoar (artificial Calculus bovis) and safflower (Carthamus tinctorius L.) was measured by ultraviolet visible-vis spectrophotometry and high-performance liquid chromatography. The effects of ESCP combined with vancomycin on MRSA by observing its biofilm viability were assessed using a 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium5-carboxanilide reduction assay and scanning electron microscopy. Additionally, enzyme activity was measured by plasma coagulase test and DNase test.ResultsThe cholic acid content of the artificial C. bovis extract was 7.34 (0.81) mg/g, and the HSYA content of the C. tinctorius extract was 9.18 (0.09) mg/g. The minimal inhibitory concentrations of ESCP and vancomycin were 25.6 mg/mL and 2 μg/mL. The minimum bactericidal concentration of ESCP was 51.2 mg/mL. ESCP combined with vancomycin could inhibit the expression of coagulase and bacteria in mature biofilms. Neither ESCP nor vancomycin had a significant effect on DNase.ConclusionThis study is the first to show that ESCP combined with vancomycin inhibits coagulase and MRSA embedded in mature biofilms and that it represents a promising treatment for MRSA infection.