Erythromycin Susceptibility of Staphylococcus epidermidis in Biofilm / 中华医院感染学杂志

ABSTRACT

OBJECTIVE To give experimental basis for further investigation on Staphylococcus epidermidis biofilm resistance,we investigated the erythromycin repression of the planktonic,resuspended and biofilm cells.METHODS log Reduction of the planktonic,resuspended and biofilm cells of S.epidermidis strain 1457 and wild isolate S 68 was tested under 100 MIC erythromycin.The cells inside biofilm were observed by transmission electron microscope.RESULTS log Reduction of the planktonic and resuspended cells of S.epidermidis 1457 were 5.56?0.11 and 5.28?0.08,respectively,after 4h under 100 MIC erythromycin,which was higher than that of biofilm cells(P0.05).The tendency of the log reduction of isolate S 68 was the same as that of strain 1457.The cells of biofilm without erythromycin were spherical and of even distributed,but the swelling,liquefied cells and cell debris were observed in the biofilm with erythromycin after 12h.The arrangement of cells inside biofilm with erythromycin was looser than that without erythromycin.CONCLUSIONS The erythromycin resistance of biofilm cells is higher.Biofilm can give protection for the bacteria to avoid the killing of action by antibiotics.