The Effect Of Zishe Cream On Staphylococcus Aureus In Vitro

Objective:Observe the effect of Zishe cream on staphylococcus aureus and its effecton the production of staphylococcus aureus superantigen in vitro.Methods: Culture staphylococcus aureus strains isolated from skin lesions of patientswith atopic dermatitis that produce both enterotoxin A and enterotoxin B (includingboth methicillin-sensitive staphylococcus aureus and methicillin-resistantstaphylococcus aureus),as well as standard strain ATCC29213. The sensitivity of theClinical isolates and the standard strain to Zishe cream were tested through diskdiffusion test, with mupirocin disk as positive control and disk without drugs asnegative control; Trace broth microdilution modincation to determine the minimalinhibitory concentration of Zishe cream on staphylococcus aureus.Using spectrophotometer to measure OD value of liquid culture from0to24hours,and drawing general time-growth curve for24hours. The level of staphylococcusaureus superantigen SEA, SEB before and after the intervention of Zishe cream isderermined by double antibody sandwich enzyme-linked immunoassay (ELISA).Results：The ATCC29213, MSSA,MRSA achived19.33mm,18.75mm and18.79mmrespectively in diameter of inhibition zone after affected by Zishe cream at theconcentrion of1g/ml.And there was no significant difference of the diameter between1g/ml of Zishe cream and128μｇ/ml of Mupirocin（P＞0.05）.The minimuminhibitiory concentration of the Zishe cream effect on ATCC29213,MSSA and MRSAwere1.54mg/ml,1.68mg/ml and1.54mg/ml,respectively.And there was nosignificant difference among them(P＞0.05). At the concentration of1.68mg/ml(minimum inhibitiory concentration), Zishe cream Inhibited the growth ofstaphylococcus aureus:after the intervention of Zishe cream, the3strains of S. aureusalmost had no obvious change in the OD in0-12hours, contrasted with0h（P＞0.05），the latent period was significantly prolonged contrasted with the control groups (<4h). The OD of bacteria began to increase slowly at the14th hour（P<0.05），and at the22th hour reached the plateau,and the OD of bacteria incubated with Zishe cream were significantly lower than the control groups in same period，it was stilldistinctively lower at the24th hour; There was no significant difference whencompared with S. aureus incubated with Mupirocin（P＞0.05）. As the concentrationof Zishe cream range from0.105mg/ml to3.36mg/ml,the production of SEA、SEBreduced more.The level of SEB was lower at the concentration of1/32MIC（0.0525mg/ml）Zishe cream（P<0.05）,and level of SEA、SEB were also lower atthe concentration of0.105mg/m（lP<0.05）,but there was still no significant differencein the OD of the bacteria（P＞0.05）,contrast with the control groups.Conclusion: Zishe cream could inhibit the growth of staphylococcus aureus, bothMSSA and MRSA multiplying could suppressed by Zishe cream;The secretion ofsuperantigens SEA,SEB of MRSA and MSSA are reduced by Zishe cream; there is nosynchronization on the inhibition of staphylococcus aureus growth and reduction oftheir superantigens SEA、SEB;Then we suppose that the mechanism of reduction ofthe superantigens SEA、SEB is irrelevant to the inhibition of bacterial proliferation.