禽源耐黏菌素大肠杆菌耐药性分析

为研究禽源大肠杆菌的黏菌素耐药及mcr-1(mobile colistin resistance)基因携带情况并检测耐黏菌素大肠杆菌的耐药表型,分析其多重耐药性,从湖北不同地区分离并鉴定大肠杆菌117株,耐黏菌素大肠杆菌的比例为27.35%(32/117),其中mcr-1基因携带率为71.88%(23/32)。23株mcr-1阳性菌株的黏菌素MIC值均介于4～16μg/mL之间,为低水平的耐药。其中22株呈现出不同程度的多重耐药性,并对四环素、复方新诺明、氨苄西林的耐药率较高(85%),其次是萘啶酸和环丙沙星(73.91%);对阿奇霉素和氨曲南的耐药率较低(20%);未发现对阿米卡星和亚胺培南耐药的菌株。mcr-1阳性菌株对萘啶酸、环丙沙星、头孢曲松及头孢噻肟这4种抗生素的耐药率显著高于mcr-1阴性菌株(P0.05)。本研究为mcr-1介导的耐黏菌素机制研究提供了参考数据。     

麻旺鸭源大肠杆菌耐药表型分析及β-内酰胺酶、PMQR基因检测

本研究旨在了解麻旺鸭源大肠杆菌对β-内酰胺类、氨基糖苷类、四环素类、酰氨醇类、氟喹诺酮类和磺胺类药物的耐药情况以及β-内酰胺酶基因和质粒介导的喹诺酮耐药(plasmid-mediated quinolone resistance, PMQR)基因流行情况。从重庆市酉阳县4个麻旺鸭养殖场采集146份泄殖腔拭子样品,经选择性增菌和PCR扩增大肠杆菌特异性phoA基因分离鉴定大肠杆菌。采用纸片扩散法测定分离菌对25种抗菌药物的耐药性并检测分离菌株中的β-内酰胺酶基因和PMQR基因。结果显示：共分离到大肠杆菌146株。这些菌株对氨苄西林、头孢唑啉耐药严重,耐药率超过50%;对庆大霉素、阿米卡星、氧氟沙星完全敏感。分别有111株(76.0%)和83株(56.8%)菌携带至少1种β-内酰胺酶基因和PMQR基因,其中bla_TEM(74.0%,108/146)和qnrS(54.8%,80/146)基因最为流行。63株菌同时携带β-内酰胺酶基因和PMQR基因。麻旺鸭源大肠杆菌对常用抗菌药物存在耐药,且广泛携带β-内酰胺酶基因和PMQR基因。     

合肥地区动物源致病性大肠杆菌ESBLs和PMQR基因流行分布

从安徽省合肥地区多个养殖厂分离鉴定了65株致病性大肠杆菌,用PCR方法检测ESBLs和PMQR基因的流行分布情况,用微量肉汤稀释法测定30株ESBLs和/或PMQR阳性菌对16种抗菌药物的最小抑菌浓度.PCR结果显示:ESBLs阳性率为24.6％(16/65),分别为blaOXA(16株)、blaTEM(15株)和blaCTX-M(14株),未检出blaSHV; PMQR的阳性率为46.2％(30/65),分别为qnrA(9株)、qnrS(18株)、aac(6')-Ib～cr(28株),未检出qnrB、qnrC、qnrD和qepA;且携带ESBLs基因的阳性菌株均携带PMQR基因.首次检测出有7株大肠杆菌同时携带ES-BLs基因型(blaOXA、blaTEM、blaCTX-M)和PMQR基因型(qnrA、qnrS、aac(6')-Ib-cr).药物敏感性测定结果显示:30株携带ESBLs和/或PMQR基因的阳性大肠杆菌对16种抗菌药物的耐药率为16.7％～100％,耐药谱较广,耐药性较严重.16株同时携带ESBLs和PMQR基因的阳性菌株对11种及11种以上药物耐药的菌株占87.5％,14株仅携带PMQR基因的阳性菌株对11种及11种以上药物耐药的菌株占28.5％,表明携带PMQR基因的同时携带ESBLs基因大大增强了菌株的耐药性,携带耐药基因的数量和种类与菌株的多重耐药性相关.     

仔猪腹泻性大肠杆菌多黏菌素耐药基因mcr-1筛查及其多重耐药基因检测

为了摸清四川地区致仔猪腹泻性大肠杆菌多黏菌素耐药基因mcr-1流行状况及阳性菌株多重耐药基因携带情况,试验采用含多黏菌素E(2μg/mL)的伊红美蓝琼脂培养基筛选多黏菌素E耐药性大肠杆菌,并通过PCR方法检测多黏菌素E耐药基因mcr-1及mcr-1阳性菌株的β-内酰胺酶类、磺胺类、四环素、喹诺酮类、氯霉素类等多重耐药基因的共存状况。结果表明:获得的84株多黏菌素E耐药性大肠杆菌中有49株携带mcr-1耐药基因,阳性率为58.33%。49株mcr-1阳性菌株中磺胺类耐药基因sul1、sul2、sul3检出率为(100%,49/49);氯霉素类耐药基因FLOR检出率为(100%,49/49);四环素类耐药基因tetA的检出率最高(100%,49/49),其次为tetM(63.27%,31/49);β-内酰胺酶类耐药基因以bla_(TEM)与bla_(CMY)为主,检出率分别为75.51(37/49)和61.22%(30/49);喹诺酮类耐药基因以qnrS(87.76%,43/49)、acc-ib-cr(61.22%,30/49)、oqxAB(75.51%,37/49)为主,而qnrA、qnrC、qnrD的检出率均为0。说明携带多黏菌素E耐药基因mcr-1的阳性菌株的多重耐药情况非常严重,从而导致耐药基因的广泛存在以及高水平的传播,威胁人类的健康。     

青岛地区鸡源bla_(NDM)与mcr-1耐药基因的流行性试验

为了解青岛地区鸡源大肠杆菌中碳青霉烯耐药基因bla_(NDM)与黏菌素耐药基因mcr-1流行情况。2018-2019年从青岛地区共采集195份鸡直肠拭子和盲肠内容物,通过选择性培养基筛选目的菌株和16S rRNA菌属鉴定。采用琼脂稀释法测定菌株对10种常见重要抗菌药物的敏感性,通过PCR检测bla_(NDM)与mcr耐药基因并测序。结果共计分离到186株大肠杆菌,其中鸡泄殖腔源98株,鸡盲肠源88株。药敏试验结果显示,分离菌株对阿莫西林、四环素、头孢氨苄耐药率均高于90%;多黏菌素81.2%、庆大霉素88.7%、氧氟沙星86.6%和头孢噻肟87.1%,呈现较高的耐药率;对替加环素(4.8%)则表现低水平耐药率。进一步分析发现,62.9%的测试菌株对8种以上药物耐药,表现多重耐药。耐药基因检测揭示了31.2%(n=58)大肠杆菌携带mcr-1基因,7.5%(n=14)携带bla_(NDM),包括1株bla_(NDM-1)、1株bla_(NDM-9)、12株bla_(NDM-5)。其中6株大肠杆菌株同时携带了bla_(NDM)和mcr-1,包括5株bla_(NDM-5)+mcr-1和1株bla_(NDM-9)+mcr-1。表明山东青岛地区鸡源大肠杆菌耐药菌检出率较高,多重耐药现象严重;且bla_(NDM)和mcr-1存在共同传播。     

携带mcr-1鸡源大肠杆菌耐药性及传播特性的初步分析

为研究携带mcr-1鸡源大肠杆菌的耐药性、耐药基因的携带情况及mcr-1基因的传播特性,本研究以从河南、湖北、江西等7个省份分离的182株鸡源大肠杆菌作为研究对象,采用PCR方法扩增其mcr-1基因,并对mcr-1阳性菌株携带的其他耐药基因进行检测.结果显示,在182株大肠杆菌中,mcr-1基因阳性率达到18.13％(...     

仔猪腹泻源大肠杆菌耐药性调查及耐药基因检测

对泰州地区分离的仔猪腹泻源大肠杆菌的耐药性及其携带的相关耐药基因情况进行检测,为养殖场今后合理用药提供科学依据。采用微量肉汤稀释法对分离的49株大肠杆菌进行8种抗菌药物的药敏试验;采用PCR方法对多黏菌素耐药基因mcr-1及超广谱β-内酰胺酶(ESBL)耐药基因blaCTX-M、blaSHV和blaTEM进行检测。药敏试验结果显示:大肠杆菌对氯霉素、氟苯尼考、氨苄西林、四环素、庆大霉素和恩诺沙星等的耐药率分别达到100%、97.96%、95.92%、89.80%、59.18%和51.02%;而对多黏菌素E和头孢噻呋的耐药率也达到44.90%和32.65%。进一步耐药基因检测结果显示:ESBL耐药基因中blaCTX-M的检出率最高,达到12.24%(6/49);其次为blaSHV,8.16%(4/49);有一株大肠杆菌携带blaTEM基因。其中一株同时携带blaCTX-M和blaSHV。多黏菌素耐药基因mcr-1的检出率达到30.61%(15/49),其中4株同时携带blaCTX-M基因。泰州地区分离大肠杆菌耐药情况和多重耐药现象较为严重,多黏菌素耐药基因mcr-1及ESBL耐药基因blaCTX-M、blaSHV和blaTEM的广泛分布表明这些耐药基因存在快速传播的风险。因此,有必要加强猪场细菌耐药性监测。     

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

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。     

2012~2013年山东省禽源大肠杆菌中质粒介导喹诺酮类药物耐药基因的检测

为研究近年来山东省禽源致病性大肠杆菌中质粒介导喹诺酮类药物耐药(plasmid-mediated quinolone resistance,PMQR)基因的基因型分布,及其对喹诺酮类抗生素的耐药性的影响,分别采用针对qnrA、qnrB、qnrC、qnrD、qnrS、oqxA、oqxB与qepA 8个耐药基因的通用引物,对93株2012~2013年分离自山东省的禽源大肠杆菌进行PCR检测,并对其进行了5种喹诺酮类药物的药敏试验。结果表明山东省禽源大肠杆菌对5种喹诺酮类抗生素均产生了较高耐药性(50.54%~86.30%);PMQR基因携带率达到60.21%(56/93),其中26.88%(25/93)的菌株携带2种PMQR基因,1.07%(1/93)的菌株携带3种PMQR基因;qnrA、qnrB、qnrC、qnrD与qepA基因未被检测到,qnrS、oqxA和oqxB基因在山东省禽源致病性大肠杆菌中分布较为广泛,其检出率依次为22.58%(21/93)、40.86%(38/93)和24.73%(23/93)。     

潍坊市肉鸭源大肠杆菌喹诺酮类药物耐药性的检测

为研究近年来山东省肉鸭源致病性大肠杆菌对喹诺酮类药物的耐药性,本研究将2010年以来分离自山东省潍坊市发病肉鸭的232株大肠杆菌进行了洛美沙星、培氟沙星、氧氟沙星、诺氟沙星等4种喹诺酮类药物的药敏试验,并对其进行了质粒介导喹诺酮类药物耐药基因的PCR检测。结果表明,山东省潍坊市肉鸭源大肠杆菌对4种喹诺酮类抗生素均产生了较高耐药性(54.31%~82.760%),质粒介导喹诺酮类耐药(PMQR)基因携带率达到58.19%(135/232),26.29%(61/232)的菌株携带两种产PMQR基因,1.72%(4/232)的菌株携带三种PMQR基因。未检测到qnr A、qnr B、qnr C、qnr D与Qep A基因,qnr S、oqx A和oqx B基因在山东省禽源致病性大肠杆菌中分布较为广泛,其检出率依次为19.83%(46/232)、41.81%(97/232)和26.29%(61/232)。     

Scrapie in goats in Cyprus

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.     

Heartworm in dogs in Canada in 1984

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.

     

Heartworm in dogs in Canada in 1989

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.

     

Heartworm in dogs in Canada in 1987

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%).     

Heartworm in dogs in Canada in 1986

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.

     

Heartworm in dogs in Canada in 1983

In late December 1983, 2 800 veterinarians across Canada were sent a questionnaire in order to assess the status of heartworm disease in Canada in 1983 and 26% of them responded. Veterinarians reported that 59 504 dogs were blood-tested to check for microfilariae and 771 dogs (1.30% of those tested) were found with Dirofilaria immitis. Heartworm disease was diagnosed in all provinces except New Brunswick and Newfoundland but most (733) of the cases were in Ontario.

Heartworm disease was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 31% of the cases were observed with clinical signs of heartworm disease and 64% had a history of not having left Canada. Southwestern Ontario continues to be the focus of the infection and most of the dogs there had not left the province previously.