作　　者： ; ; ; ; ; ;

机构地区： 华南农业大学兽医学院

出　　处： 《中国兽医科技》 2004年第8期17-22,共6页

摘　　要： 按常规方法提取了鸡毒霉形体参考株S6 10 、疫苗株F14 8及在氟喹诺酮类药物压力下筛选出来的耐药株的基因组DNA ,扩增了各菌株DNA旋转酶 gyrA基因片段 ,并进行了克隆、测序 ,利用DNAsis软件对测序结果进行分析。结果表明 ,S6 10 和F14 8在恩诺沙星或环丙沙星压力下均筛选出不同程度的耐药菌 ,而且恩诺沙星致鸡毒霉形体发生耐药性突变的几率高于环丙沙星 ,S6 10株耐药突变频率高于F14 8;S6 10 筛选出来的耐药菌株发生突变的位置在DNA旋转酶GyrA亚基的第 83位 (相对于大肠埃希氏菌GyrA亚基中的位置 ,以下同 )和第 87位上 ,取代模式分别为Ser→Ile、Glu→Gln ,另外 1株高水平耐药株 (Se10 ,MIC≥ 12 8)在第 10 3位也发生了氨基酸取代 (Ile→Val) ;F14 8筛选出来的耐药菌株只在DNA旋转酶GyrA亚基的第 87位发生了突变 (Glu→Gly/Gln)。 Genomic DNA of Mycoplasma gallisepticum (MG) S_(6-10),F_(14-8) and the fluoroquinolone(FQs)-resistant MG selected under the FQs pressure were prepared according to the methods described by Sambrook et al. Consequently the gyrAgene in DNA gyrase of each strains was amplified, and then cloned and sequenced. The sequencing results were analyzed with the software DNAsis. The results showed that the MG resistant strains on different level were obtained from S_(6-10) and F_(14-8) under enrofloxacin or ciprofloxacin pressure, and also suggested that the enrofloxacin had a higher potential in selecting (resistant) mutants from the same strains when compared to ciprofloxacin, however the resistant incidence in S_(6-10) was high than that in F_(14-8). The mutation site in GyrA subunit of resistants obtained from S_(6-10) were localized at position 83 (number corresponding to the amino acid position of E. coli GyrA, the same (below)) with a Ser83→Ile mutant type and 87 with a Glu87→Gln substitution mode. An additional mutation at position 103 (Ile→Val) was found in a high-level resistant. The mutation occurringin the resistants (derived) from F_(14-8)was only found at position 87 (Glu→Gly/Gln) of GyrA subunit.

关 键 词： 鸡毒霉形体 耐药性 基因 氟喹诺酮药物 病原体

领　　域： [农业科学] [农业科学] [农业科学]