ABSTRACT
To investigate the inhibitory effect and mechanism of chloroform extracts from Longdan Xiegan decoction(CELX) against hydrolytic enzymes activity of Candida albicans isolated from vulvovaginal candidiasis(VVC) patients. Secreted aspartyl proteinase(Sap), phospholipase(PL) and lipase(Lip) positive strains were identified from 15 strains of C. albicans with milk culture medium, egg yolk culture medium and tween-80 medium, respectively. Then, the activities of Sap, PL, and Lip were detected in the above media. qRT-PCR was used to detect the changes in gene expressions of aspartic protease(SAP1-7,10), phospholipase B(PLB1-2) and lipase(LIP3-6). Secreted aspartyl proteinase and phospholipase of 15 VVC clinical strains were positive, and lipase of 11 strains were positive. Compared with the blank control group, the drug CELX-containing medium(milk medium, egg yolk culture medium, tween-80 medium) experiment showed that the sedimentation of colonies decreased gradually in each culture medium with the increase of CELX dose. When the concentration of CELX was 256 mg•L⁻¹, the colony almost disappeared, which indicated the enzyme activity was significantly weakened. The results of qRT-PCR showed that SAP1, SAP2, SAP3, SAP4, SAP7, SAP9 and SAP10 were down-regulated by 62%, 55%, 62%, 84%, 61%, 51%, 68%, respectively, except for SAP5 and SAP6; and PLB1, LIP3, LIP4, LIP6 were down-regulated by 67%, 51%, 54%, 55%, respectively. The findings suggested that CELX may inhibit the activities of Sap, PL, and Lip, which are important virulence factors of C. albicans.
ABSTRACT
<p><b>OBJECTIVE</b>To observe the effect of the combination of sub-MIC sodium houttuyfonate and erythromycin on biofilm of Staphylococcus epidermidis.</p><p><b>METHOD</b>The serial dilution method was adopted to determine MIC of the combination of sodium houttuyfonate and erythromycin on S. epidermidis; the checkerboard method was used to evaluate the combination of sodium houttuyfonate and erythromycin on suspended bacteria of S. epidermidis; S. epidermidis biofilm was built in vitro, and XTT reduction assay was used to evaluate the effect of the combination of sub-MIC sodium houttuyfonate and erythromycin on the adhesion of S. epidermidis and bacterial metabolism inside the biofilm. Microscope was applied to observe the impact the single administration and combination of the two medicines under sub-MIC on biofilm morphology of S. epidermidis.</p><p><b>RESULT</b>The MIC of sodium houttuyfonate and erythromycin were 62.5, 7.812 5 mg x L(-1), respectively. The combination of 1/8MIC sodium houttuyfonate and 1/2MIC erythronmycin showed a synergistic effect on S. epidermidis. Sodium houttuyfonate, erythromycin and their combination had an inhibitory effect on the adhesion and metabolism of S. epidermidis biofilm bacteria, and made impact on the morphology of S. epidermidis biofilm.</p><p><b>CONCLUSION</b>The sub-MIC sodium houttuyfonate and erythromycin have an inhibitory effect on S. epidermidis biofilm. The combination of sodium houttuyfonate and erythromycin shows a synergistic effect in inhibiting suspended bacteria and biofilm of S. epidermidis, particularly in inhibiting the metabolism of S. epidermidis biofilm bacteria and impacting the morphology of biofilm.</p>