嗜水气单胞菌对氟喹诺酮类药物的敏感性及耐药相关基因分析  

Fluoroquinolone Susceptibility and Resistance-associated Genes in Clinical Isolates of Aeromonas hydrophila

作　　者：王晓丰[1] 薛晖[1] 丁正峰[1] 杨林[1] 

机构地区：[1]江苏省淡水水产研究所,江苏南京210017

出　　处：《江苏农业学报》2010年第6期1298-1303,共6页Jiangsu Journal of Agricultural Sciences

基　　金：江苏省科研院所社会公益研究与服务专项基金项目(BM2007705)

摘　　要：为明确嗜水气单胞菌临床分离株对常用氟喹诺酮类药物的敏感性和耐药菌株中gyrA和parC基因的突变情况。试验采用自动化细菌药敏分析仪测定4种常用氟喹诺酮类药物对23株鱼源嗜水气单胞菌的最低抑菌浓度,并依据耐药数目的不同选取9株嗜水气单胞菌,PCR扩增其gyrA及parC基因的喹诺酮抗性决定区(QRDR),直接测序后进行多序列比对分析。结果显示:嗜水气单胞菌对诺氟沙星、氧氟沙星、恩诺沙星和环丙沙星的耐药率依次为8.7%、30.4%、73.9%和43.5%;序列分析发现gyrA基因编码的第83位氨基酸存在Ser→Ile、Ser→Val的突变,parC基因编码的第87位氨基酸同样存在Ser→Ile的突变。表明临床分离的嗜水气单胞菌对恩诺沙星耐药最为严重,氧氟沙星、环丙沙星次之,对诺氟沙星较为敏感;尽管绝大多数耐药菌株的药物靶位基因QRDR区域有突变发生,但是菌株的耐药性与药物靶位基因QRDR区域有无发生突变并不存在线性关联,提示我们药物靶位的变化并非是氟喹诺酮类耐药菌株唯一的抗性机制。A general investigation about antibiotic susceptibility of Aeromonas hydrophila to fluoroquinolone was performed, and the gyrA and parC gene mutation in fluoroquinolone resistant isolates were studied. Based on these, the correlation between the gene mutation and fluoroquinolone resistance of Aeromonas hydrophila was clarified. The minimal inhibitory concentration of 23 isolates of Aeromonas hydrophila collected from freshwater fish against four types of fluoroquinolone antibiotics were determined by automated bacteria analyzer HX-21, and 9 strains of Aeromonas hydrophila were selected to amplify quinolone resistance determining regions （QRDR） in gyrA gene and parC gene. The resistance rates of Aeromonas hydrophila isolates to norfioxacin, ofloxacin, enrofioxacin and ciprofloxacin were 8.7% , 30.4% , 73.9% and 43.5%, respectively. Multiple sequence alignment results indicated that resistant strains carried a mutation point Ser----Ile or Ser--4Val at codon 83 in the gyrA QRDR, and also a mutation point Ser--Ile at codon 87 in the parC QRDR. Aeromonas hydrophila isolates had remarkable resistance to enrofioxacin, followed by ofloxacin and ciprofloxacin. Although amino acid variations were found in QRDR regions of majority drug-resistant strains, the linear correlation between them did not existed, indicating that alteration of target genes was not the only mechanism contributing to fluoroquinolone-resistant clinical isolates.

关 键 词：嗜水气单胞菌 氟喹诺酮 GYRA基因 PARC基因 

分 类 号：S941[农业科学—水产养殖]