With high concentration of sds and elevated temprature （ 43 ） ， we succeeded in eliminating plasmids from ten strains of s . aureus which were isolated from the farms of beijing suburb . according to the sensitivity test before and after plasmid remoral ， we found that 72 . 5 antibiotic resistance of s . aureus was mediated by plasmids ， and 27 . 5 encoded by chromosome . the curing test indicated that the plasmids play an important role in coding the resistance to antibiotics 从北京郊区鸡场分离到10株耐药性金黄色葡萄球菌，对这些菌株进行质粒消除，根据质粒消除前后的耐药性检测，发现耐各种药物的抗性基因大多数位于质粒上，少部分抗性基因位于染色体上，由质粒介导的耐药基因占72 . 5 % ，由染色体编码的抗性基因占27 . 5 % ，说明质粒在决定对抗生素的抵抗性中起主要作用。
