摘要
目的为进一步研究表皮葡萄球菌生物被膜的耐药机制提供实验基础,对表皮葡萄球菌浮游菌、膜内重悬浮菌和膜内菌对红霉素的敏感性进行探讨。方法检测表皮葡萄球菌1457和野生株S 68浮游菌在100倍MIC红霉素(分别为25μg/ml和320μg/ml)作用下,浮游菌、生物被膜内菌和膜内重悬浮菌的细菌对数减少值,并在透射电镜下观察膜内细菌的变化。结果表皮葡萄球菌1457在100倍MIC红霉素作用4 h后,浮游菌和重悬浮菌细菌数对数减少值分别为5.56±0.11和5.28±0.08,明显高于膜内菌1.21±0.13(P<0.05),当作用时间延长到60 h,膜内菌细菌数对数减少值为1.51±0.1;细菌形成生物被膜后重新悬浮的细菌对抗菌药物的敏感性与浮游菌相似(P>0.05);S68的细菌数对数减少趋势与1457类似;透射电镜结果显示,红霉素作用前被膜内细菌呈圆形,分布较均匀;红霉素作用12 h后,被膜内细菌含有膨胀、液化的细胞和细胞碎片,细菌排列较对照组疏松。结论膜内菌对红霉素的耐药性较高,生物被膜能保护细菌逃逸抗菌药物的杀菌作用。
OBJECTIVE To give experimental basis for further investigation on Staphylococcus epidermidis biofilm resistance, we investigated the erythromycin repression of the planktonic, resuspended and biofilm ceils. 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 ceils （P〈0. 05）. Even after 60h, the log reduction of the biofilm ceils was 1.21 ±0. 13 （P〈0. 05）. The erythromycin susceptibility of the resuspended cell was similar to that of the planktonic ones （P〉0. 05）. The tendency of the log reduction of isolate S 68 was the same as that of strain 1457. The ceils of biofilm without erythromycin were spherical and of even distributed, but the swelling, liquefied ceils and cell debris were observed in the biofilm with erythromycin after 12h. The arrangement of ceils inside biofilm with erythromycin was looser than that without erythromycin. CONCLUSIONS The erythromycin resistance of biofilm ceils is higher. Biofilm can give protection for the bacteria to avoid the killing of action by antibiotics.
出处
《中华医院感染学杂志》
CAS
CSCD
北大核心
2007年第8期923-925,共3页
Chinese Journal of Nosocomiology
基金
国家自然科学基金资助(30300296)
