共查询到20条相似文献，搜索用时 750 毫秒
1.
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茵，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(相对于大肠埃希氏茵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≥128)在第103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)。 相似文献
2.
按常规方法提取鸡毒霉形体3株临床分离株和参考株(S6-10)的基因组DNA，扩增各菌株DNA旋转酶gyrA基因片段，并克隆、测序，用DNAsis软件对测序结果进行分析。结果表明，HS1、HS2株均在GyrA亚基第87位发生了Glu87→Gly氨基酸取代，除此之外，耐药水平较高的HS2株还在第83位发生了Ser83→Ile氨基酸取代，而FL分离株虽对氟喹诺酮类药物产生了低水平耐药，但在GyrA亚基未发生任何氨基酸突变。 相似文献
3.
为了解近年来鸭源鸡杆菌(Gallibacterium anatis)的药物敏感性及其对氟喹诺酮类药物的耐药机制，以204株G.anatis为对象，选取11种抗菌药，用纸片法检测其药物敏感性，随后从中随机选取30株进行gyrA、parC基因的PCR扩增和测序，并分析喹诺酮耐药决定区编码氨基酸的突变情况。结果显示，试验菌株对复方新诺明、四环素、氟喹诺酮类药物的耐药率达86.76%以上，对头孢曲松与头孢噻肟的耐药率较低，分别为11.27%和7.35%;99.02%的菌株耐3种以上药物，92.16%的菌株耐6种以上药物，其中有6株对11种药物全部耐药；30株G.anatis全部扩增出parC基因，其中22株扩增出gyrA基因，GyrA亚基存在Ser83→Phe、Asp87→Ala/Tyr/Asn和Asp139→Tyr 3个位点氨基酸置换，ParC亚基存在Thr84→Ile、Glu88→Gly、Ala94→Val和Gly179→Val 4个位点氨基酸置换，敏感菌株不存在氨基酸位点突变，中度敏感菌株发生了3处氨基酸的替换，94.7%的耐药菌株发生了4处及以上氨基酸位点的置换。结果表明，G.anat... 相似文献
4.
15株动物源性耐氟喹诺酮类药物大肠杆菌进行PCR检测、测序、WDNASIS软件分析gyrA基因中的氟喹诺酮耐药决定区(QRDR)、AcrA以及编码与质粒介导的氟喹诺酮类药物耐药机制相关的qnrA、qnrB、qnrS、qepA和aac(6′)-Ib-cr基因。结果表明,15株耐药菌中,QRDR基因在其编码第72、75、83位或第87位氨基酸均发生突变;AcrA基因未检测到氨基酸的突变;qnrS、qepA和aac(6′)-Ib-cr耐药基因阳性菌各检测到1株,序列分析表明不存在氨基酸突变。QRDR基因编码的氨基酸4个位点发生突变,其中Ser83→Leu和Asp87→Asn 2个基因的突变均与文献报道的突变相同,双突变的7个菌株均表现为高度耐氟喹诺酮类抗生素,表明gyrA基因为大肠杆菌耐氟喹诺酮类抗生素的一个重要机制。高度耐氟喹诺酮类抗生素的菌株中有2株没有检测到氨基酸突变的存在,但是aac-(6′)-Ib-cr基因和qnrS检测为阳性,表明质粒介导的喹诺酮类耐药也可单独导致菌株的耐药。存有一个菌株gyrA基因编码的氨基酸发生突变Ser83→Leu,AcrA基因和qnrA、qnrB、qnrS、qepA和aac(6′... 相似文献
5.
耐氟喹诺酮类药物大肠杆菌基因突变耐药机制的研究 总被引：5，自引：1，他引：4
取临床分离的 4株耐药菌、实验室诱导培养获得的 3株耐药菌和 1株敏感菌 ,提取其染色体 DNA,PCR扩增 gy-r A和 par C基因片段 ,并将其克隆和测序。结果表明 ,无论是临床分离的还是实验室诱导的耐药菌 ,gyr A基因在其编码第 83位或第 87位氨基酸处均发生突变 ,par C基因在其编码第 80位或第 84位氨基酸处发生突变 ,而敏感菌 ES在2个基因位点上均未发生突变。其中 2株低度耐药菌株的 gyr A基因出现单一突变 ,使其编码的氨基酸发生改变 ,分别为 Ser83→ L eu或 Asp87→ Asn,但在 par C基因上却未发生突变 ;其余 5株高度耐药菌 gyr A基因突变导致氨基酸发生改变 :Ser83→ L eu(n=5 ) ,Asp87→ Asn(n=4 )和 Tyr(n=1) ,par C基因突变导致氨基酸改变 :Ser80→ Ile(n=4 )和Glu84→ L ys(n=1)。这 2个基因的突变均与文献报道的突变相同 ,表明 gyr A基因 Ser83和 Asp87突变以及 par C基因 Ser80和 Glu84突变可能与大肠杆菌的喹诺酮类药耐药机制有关 ,且低度耐药只在 gyr A基因上出现单一位点突变 ,当高度耐药时 ,才同时在 par C基因上出现突变 相似文献
6.
猪源链球菌对环丙沙星耐药性与耐药基因突变的相关性研究 总被引：1，自引：0，他引：1
通过微量稀释法测定28株猪源链球菌对环丙沙星的MIC值,研究东北地区猪源链球菌对环丙沙星耐药性与parC、gyrA基因突变的相关性.通过PCR方法扩增parC和gyrA基因喹诺酮耐药决定区(QRDR)并测序分析;18株耐药菌在parC基因80位的突变(AGC→ATT)导致氨基酸Ser→Ile突变,11株高度耐药菌在gyrA基因81位的突变(CAG→)CAT、CTT或CTA)导致氨基酸Ser→Ile、Phe或Tyr的突变.当菌株对环丙沙星的MIC值≤1μ/mL时,parC和gyrA基因的QRDR区均未有突变;而当MIC ≥2μg/mL时,ParC的氨基酸发生了Ser80→Ile的突变,同时发生GyrA氨基酸Ser81突变的菌株,耐药水平很高.研究表明,环丙沙星低水平类耐药是由于拓扑异构酶Ⅳ改变引起,而高水平耐药是由拓扑异构酶Ⅳ、DNA旋转酶共同改变引起的.实验结果证明,在一定条件下,耐药性的高低与突变位点的多少成正比. 相似文献
7.
猪源大肠杆菌质粒和染色体介导的喹诺酮类药的耐药机制 总被引：3，自引：0，他引：3
采用微量肉汤稀释法对31株猪源大肠杆菌进行6种喹诺酮类药物的敏感性测定,聚合酶链式反应检测质粒介导的喹诺酮类耐药（PMQR）基因qnr、qepA和aac（6′）-Ib-cr,并分析PMQR基因阳性菌株染色体gyrA、gyrB、parC、parE基因的喹诺酮耐药决定突变区（QRDRs）突变。结果显示,31株猪源大肠杆菌对兽医临床常用的氟喹诺酮类药物均呈现耐药。在31株猪源肠杆菌中共检测到2株携带qnrB10和4株携带qnrS1基因的大肠杆菌,未检测到qnrA、qepA和aac（6′）-Ib-cr。在PMQR阳性菌株gyrA基因的QRDRs中,低耐药菌株的gyrA基因出现83位S→W突变,高耐药菌株的gyrA基因同时出现83位S→L和87位D→N突变。而在parC基因的QRDRs中,大部分耐药菌株出现80位S→I突变,1株耐药菌株出现45位V→L突变。gyrB和parE基因的QRDRs未检测到突变。结果表明,本地区猪源大肠杆菌对兽医临床常用的氟喹诺酮类药物耐药严重,PMQR的出现和QRDRs的点突变可同时协同贡献对喹诺酮类耐药,而PMQR的出现加速了喹诺酮类耐药基因的快速传播。 相似文献
8.
《黑龙江畜牧兽医》2017,(16)
为了解大肠杆菌对氟喹诺酮类药物的耐药机制和喹诺酮耐药决定区GyrA、GyrB、ParC、ParE四种基因的流行情况,采用聚合酶链式反应(PCR)技术对30株虎源大肠杆菌的耐药菌株进行了氟喹诺酮类药物耐药基因的检测,并对目的片段进行测序分析。结果表明:GyrA、GyrB、ParC、ParE阳性率分别为40.00%、63.33%、63.33%、40.00%;GyrA亚基发生Ser83→Leu、Asp87→Asn、Glu214→Gly的突变,GyrB亚基发生Ser195→Asn的突变,ParC亚基上氨基酸未发生取代,ParE亚基发生Ser85→Ala的突变。说明GyrA、GyrB亚基上发生的氨基酸替代是耐药菌对氟喹诺酮类药物产生耐药性的主要机制之一。 相似文献
9.
《动物医学进展》2020,(4)
为了解动物源大肠埃希菌对氟喹诺酮类药物的耐药情况及其与gyrA基因突变的联系,采用微量肉汤稀释法测定200株猪鸡源大肠埃希菌对恩诺沙星和氧氟沙星的最低抑菌浓度(MIC);对大肠埃希菌的gyrA基因片段进行PCR扩增,产物进行变性高效液相色谱(DHPLC)检测和序列测定。结果表明,200株动物源大肠埃希菌对恩诺沙星和氧氟沙星的耐药率分别为44.5%和41.0%;144株大肠埃希菌gyrA基因产物的DHPLC图谱有异常峰型,即核苷酸突变率为72.0%;测序证实gyrA基因存在5个突变位点,其中2个位点的突变可导致Ser83→Leu和Asp87→Asn/Tyr,突变率分别为54.0%和24.0%,其余3个位点为同义突变点;结合恩诺沙星耐药情况可知,敏感菌株gyrA基因的氨基酸突变率最低(18.5%),其次为中介菌株(56.5%),耐药菌株最高(78.6%),氧氟沙星测试结果与此趋势一致。由此可知动物源大肠埃希菌gyrA基因突变引起的氨基酸替代与氟喹诺酮耐药高度相关。 相似文献
10.
取临床分离的、对5种氟喹诺酮类药物（环丙沙星、氧氟沙星、恩诺沙星、单诺沙星和沙拉沙星）均耐药的9株鸡源性沙门氏菌耐药株,提取其染色体DNA。设计引物gyrAF和gyrAR、gyrBF和gyrBR,分别扩增菌株DNA旋转酶gyrA基因和gyrB基因的氟喹诺酮类耐药决定区（QRDR）,对PCR扩增产物进行测序及序列分析。与质控菌株相比,9株临床分离耐药株中只有菌株38和60的gyrA基因发生单碱基突变,菌株38的gyrA基因第371位碱基发生C→T突变,菌株60的gyrA基因第350位碱基发生A→C突变,两处突变均位于QRDR内,其余菌株的核苷酸未发生任何突变。菌株38的碱基突变导致gyrA基因第99位氨基酸发生R→C取代,即Arg→Cys;菌株60的碱基突变导致gyrA基因第92位氨基酸发生M→L取代,即Met→Leu。9株临床分离鸡源性沙门氏菌氟喹诺酮类耐药株gyrB基因QRDR的核苷酸序列与质控菌株完全相同;只有菌株42的gyrB基因第1592位碱基发生C→A突变,但其位于gyrB基因QRDR之外,且菌株42的gyrB基因的碱基突变并没有导致相应氨基酸的改变。上述结果提示,DNA旋转酶gyrA基因和gyrB基因QRDR突变可能并非沙门氏菌耐药性产生的主要原因。 相似文献
11.
12.
Ovine scrapie was first recorded in Cyprus in 1985. Subsequently four dairy goats kept in two mixed flocks with affected sheep developed characteristic clinical signs similar to those seen in sheep. Fifteen goats from the two flocks were examined histologically and neurological lesions consistent with a diagnosis of scrapie were found in the four animals and in three others which had subsequently developed early neurological signs. These lesions were similar to those of naturally-affected sheep although neuronal degeneration and vacuolation were more severe in some cases. 相似文献
13.
Owen J Slocombe D McMillan I 《The Canadian veterinary journal. La revue veterinaire canadienne》1986,27(9):324-328
In late December 1985, 1485 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1985 and 44% of them responded. Veterinarians reported that 137,300 dogs were blood-tested to check for microfilariae and 1210 dogs were found with heartworm. Another 36 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number diagnosed in 1985 as 1247 (0.91%).
Heartworm was reported from all provinces except Prince Edward Island, Newfoundland and Saskatchewan but most (1126) of the cases were in Ontario. Southwestern Ontario continued to be the primary focus of the infection in Canada. From Quebec, 91 cases were reported mostly from and around Montreal. From Manitoba, 19 cases were reported from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 28% of the cases were observed with clinical signs of heartworm disease and 78% had a history of not having left Canada.
相似文献14.
Slocombe JO McMillan I 《The Canadian veterinary journal. La revue veterinaire canadienne》1989,30(6):504-508
In late November 1988, 1581 small and mixed animal clinics and institutional veterinarians across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1988, and 46% of them responded. Veterinarians reported that 181,577 dogs were blood-tested for heartworm disease and 367 dogs were found with D. immitis microfilariae. Another 60 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1988 as 441 (0.24%). 相似文献
15.
Slocombe JO McMillan I 《The Canadian veterinary journal. La revue veterinaire canadienne》1985,26(10):323-327
In late December 1984, 1853 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1984 and 35% of them responded. Veterinarians reported that 97,794 dogs were blood-tested to check for microfilariae and 1417 dogs (1.45% of those tested) were found with heartworm. Another 34 dogs were amicrofilaremic, but were diagnosed as having heartworm disease, to give the total number diagnosed in 1984 as 1451 (1.48%). Heartworm was reported from all provinces except Prince Edward Island and Newfoundland but most (1310) of the cases were in Ontario. In Quebec, 126 cases were reported mostly from west of Montreal.
Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 27% of the cases were observed with clinical signs of heartworm disease and 72% had a history of not having left Canada. Southwestern Ontario continued to be the primary focus of the infection.
相似文献16.
17.
In late November 1989, 1732 clinics and institutional veterinarians were sent a questionnaire to assess the status of Dirofilaria immitis, and 51.7% responded. Of 247,716 dogs tested, 394 had D. immitis microfilariae and 51 were amicrofilaremic for a total of 445 cases and heartworm prevalence of 0.17%. Most (408) of these dogs had no preventive medication and the prevalence among dogs tested and unprotected was 1.01%. That prevalence was considerably higher in endemic areas. Thirty-seven dogs with heartworm had preventive medication. Heartworm was most frequent in companion dogs over three years of age maintained outdoors in rural areas. About 75% of the cases had never left Canada, 26% had clinical signs and 125 were not treated.
Heartworm was reported from British Columbia, Manitoba, Ontario, Quebec, Nova Scotia and Newfoundland, but 383 cases were in Ontario. South-western Ontario was the primary focus of infection. There were 33 cases in Quebec and 24 in Manitoba, mainly found in and around Metropolitan Montreal and Winnipeg respectively.
相似文献18.
Slocombe JO McMillan I 《The Canadian veterinary journal. La revue veterinaire canadienne》1988,29(8):641-646
In late November 1987, 1246 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1987, and 50% of them responded. Veterinarians reported that 165,428 dogs were blood tested for heartworm disease and 511 dogs were found with D. immitis microfilariae. Another 78 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1987 as 589 (0.35%). 相似文献
19.
Owen J Slocombe D McMillan I 《The Canadian veterinary journal. La revue veterinaire canadienne》1987,28(8):491-495
In late December 1986, 1224 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1986; 46% of them responded. Veterinarians reported that 150,989 dogs were blood-tested for microfilariae and 869 dogs were found with heartworm. Another 65 dogs were amicrofilaremic but diagnosed with heartworm disease and one was found with heartworm at necropsy to give the total number diagnosed in 1986 as 935 (0.62%).
Heartworm was reported from Manitoba, New Brunswick, Ontario and Quebec, but most (810) of the cases were from Ontario. South-western Ontario continued to be the primary focus of the infection in Canada. There were 103 cases reported from Quebec, mostly from and around Montreal, and 21 cases from Manitoba, from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 33% of the cases were observed with clinical signs of heartworm disease and 81% had a history of not having left Canada.
相似文献20.