摘要
旨在了解猪链球菌对氟喹诺酮类药物耐药性与parC、gyrA基因突变的相关性,通过微量稀释法测定34株猪链球菌对4种氟喹诺酮类药物的MIC值,采用PCR方法扩增并测序分析了临床分离的猪链球菌对氟喹诺酮类药物10株耐药株和9株敏感株的parC和gyrA基因喹诺酮耐药决定区(QRDRs)。在氟喹诺酮类药物耐药菌株parC基因QRDRs发生Ser79→Phe、Arg 87→Leu的氨基酸突变,在4株高度耐药菌株gyrA基因QRDRs发生Arg66→Ser,Ser81→Arg氨基酸突变;当菌株对氟喹诺酮类药物敏感时,parC和gyrA基因的QRDR区均未有突变;而当MIC≥32μg.L-1时,parC的氨基酸发生了Ser79→Phe的突变,同时发生gyrA氨基酸Arg66→Ser,Ser81→Arg突变。结果表明,猪链球菌对氟喹诺酮类药物低水平类耐药是由parC单一位点突变引起,而高水平耐药是由parC和gyrA双位点突变引起。
To detect the relationship between fluoroquinolone resistance and gyrA and parC gene mutation in Streptococcus suis.The MIC of 34 strains of Streptococcus suis were determined by microdilution.The genes encoding the quinolone-resistance determining region（QRDRs） of parC and gyrA in fluoroquinolone-susceptible and-resistant Streptococcus suis clinical isolates were identified and sequenced.Ser to Phe and Arg to Leu mutation at position 79 and 87 of the parC gene was detected in fluoroquinolone resistance S.suis,and Arg to Ser,or Ser to Arg mutations at the position 66 or 81 of gyrA gene were detected in 4 highly resistance strains;no amino acid changes in gyrA or parC were detected for 9 fluoroquinolone-susceptible strains,the mutations in both genes was found in the strains with MIC of fluoroquinolone higher than 32μg·L-1.Mutations in parC gene result in low level resistance against fluoroquinolone,and high level resistance is resulted from the mutations in gyrA and parC both genes.
出处
《畜牧兽医学报》
CAS
CSCD
北大核心
2011年第4期600-604,共5页
ACTA VETERINARIA ET ZOOTECHNICA SINICA
基金
河北省自然基金资助项目(C2009000877)
河北省科技厅科技支撑项目(09220402D)
河北省教育厅计划项目(2008448)
