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为探究明胶液化的表型与其5种毒力基因在不同来源和不同种属猪肠球菌中的分布差异,本研究采用PCR方法以及明胶液化试验对湖南分离的375株肠球菌携带的明胶酶基因(gelE)、调控gelE表达的毒力基因反应调节子基因(fsrA)、前肽加工蛋白基因(fsrB)、组氨酸激酶基因(fsrC)、丝氨酸蛋白酶基因(sprE)共5种毒力基因的分布情况以及液化明胶现象进行检测。结果显示,共263株肠球菌检测到了毒力基因,检出率分别为41.3%(gelE)、45.9%(fsrA)、50.9%(fsrB)、48.8%(fsrC)、48.8%(sprE)。能够同时检测到5种毒力基因的菌株共有110株,其中粪肠球菌106株,且该5种毒力基因在106株粪肠球菌中的检出率均为最高,另外4株为其它肠球菌。在明胶液化试验中,共有155株肠球菌检测到gelE基因,但只有106株能够发生明胶液化现象,且这些菌株正是能够同时检测到5种毒力基因的106株粪肠球菌,而另外4株能够同时检测到5种毒力基因的其它肠球菌却不能发生明胶液化现象。结果表明,粪肠球菌是肠球菌中主要携带毒力基因的菌属,与屎肠球菌以及其它肠球菌相比,更容易出现液化明胶的表型,这可能与粪肠球菌中某些明胶液化的机制有关,且除gelE外,参与gelE表达的几种毒力基因对该表型的出现也具有一定的影响。 相似文献
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肠球菌毒力因子研究进展 总被引：1，自引：0，他引：1
肠球菌(Enterococcus)是人和动物肠道的正常菌群,通常不引起发病,为一种重要的机会致病菌.最近几年,由于免疫制剂的广泛使用,侵入性治疗机会的增加和抗生素的过渡使用,尤其是第3代头孢菌素的广泛应用,使得肠球菌的感染不断上升,成为医院内感染的主要致病菌.肠球菌致病机制与其致病岛编码的毒力因子表面蛋白、溶血素、蛋白明胶酶等有关,肠球菌致病机理不是由单一毒力因子所决定,而是多种毒力因子共同作用的结果.文章综述了肠球菌的各种潜在毒力因子的生物特性及其与致病性的关系,为预防和控制肠球菌感染提供参考. 相似文献
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Harisberger M Gobeli S Hoop R Dewulf J Perreten V Regula G 《Zoonoses and public health》2011,58(6):377-387
Antimicrobial resistance is an emerging concern to public health, and food-producing animals are known to be a potential source for transmission of resistant bacteria to humans. As legislation of the European Union requires to ban conventional cages for the housing of laying hens on the one hand, and a high food safety standard for eggs on the other hand, further investigations about the occurrence of antimicrobial resistance in alternative housing types are required. In this study, we determined antimicrobial resistance in indicator bacteria from 396 cloacal swabs from 99 Swiss laying hen farms among four alternative housing types during a cross-sectional study. On each farm, four hens were sampled and exposure to potential risk factors was identified with a questionnaire. The minimal inhibitory concentration was determined using broth microdilution in Escherichia coli (n=371) for 18 antimicrobials and in Enterococcus faecalis (n=138) and Enterococcus faecium (n=153) for 16 antimicrobials. All antimicrobial classes recommended by the European Food Safety Authority for E. coli and enterococci were included in the resistance profile. Sixty per cent of the E. coli isolates were susceptible to all of the considered antimicrobials and 30% were resistant to at least two antimicrobials. In E. faecalis, 33% of the strains were susceptible to all tested antimicrobials and 40% were resistant to two or more antimicrobials, whereas in E. faecium these figures were 14% and 39% respectively. Risk factor analyses were carried out for bacteria species and antimicrobials with a prevalence of resistance between 15% and 85%. In these analyses, none of the considered housing and management factors showed a consistent association with the prevalence of resistance for more than two combinations of bacteria and antimicrobial. Therefore we conclude that the impact of the considered housing and management practices on the egg producing farms on resistance in laying hens is low. 相似文献
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根据GenBank公布的基因序列,分别针对肠球菌属及其毒力基因cylA、esp和AS设计合成了4对引物。通过改进模板DNA提取方法和优化反应条件,建立了可以同时测定肠球菌和其携带的3种主要毒力基因的多重PCR方法。经过对不同来源的疑似肠球菌分离株进行检测,该多重PCR方法具有快速、可靠的特点。在不同来源的疑似肠球菌菌株中,临床感染分离株携带上述3种毒力基因的比例均高于鲜肉分离株和粪便分离株（分别为84．2％、55．7％和27．1％）;而且在各种来源肠球茵菌株中这3种毒力基因的携带率以cylA最高。 相似文献
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对致羔羊脑炎肠球菌E129-3菌株溶血素进行检测分析，并利用光学显微镜和电子显微镜观察其对兔红细胞的作用，探讨了肠球菌溶血素的特性及溶血类型。结果表明，小白鼠、兔、犬红细胞对该溶血素最敏感，牛红细胞不敏感。该溶血素可以被DTT、Ca^2＋活化，被蛋白酶K、EDTA、Zn^2＋、Cu^2＋抑制。在培养后2h，细胞浆内着色不一致或密度降低，5h时红细胞数量明显减少，细胞膜较完整。提示，肠球菌溶血素为成孔蛋白类溶血素。 相似文献
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为研究我国猪源肠球菌的耐药情况,本研究采集18个省市猪养殖场的粪便样品836份进行了肠球菌的分离鉴定,并通过琼脂稀释法测定11种抗菌药物的最小抑菌浓度。结果显示:从836份样品中共分离出225株肠球菌,其中屎肠球菌106株,粪肠球菌56株,小肠肠球菌34株,鹑鸡肠球菌17株,铅黄肠球菌7株,坚忍肠球菌4株,Enterococcus thailandicus 1株。所有的肠球菌对被检抗菌药物耐药程度由高到低依次是四环素(98.2%)、阿米卡星(94.7%)、多西环素(89.3%)、米诺环素(88.9%)、氟苯尼考(88.4%)、红霉素(86.2%)、环丙沙星(63.1%)、氨苄西林(33.8%)、氯霉素(29.8%),未检测到万古霉素和利奈唑胺耐药菌株。除氨苄西林、万古霉素、利奈唑胺外,粪肠球菌对其余8种被检抗菌药物耐药率均高于屎肠球菌。小肠肠球菌对阿米卡星、红霉素、四环素、多西环素、米诺环素5种抗菌药物的耐药率高于屎肠球菌。肠球菌的多重耐药情况集中在6耐、7耐和8耐,占肠球菌总数的72.9%。本研究表明我国猪源肠球菌对常见抗菌药物耐药率较高,应引起更多关注。 相似文献
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K Pedersen G W Christensen M Steffensen P Schyum A K Johansen 《Acta veterinaria Scandinavica》1992,33(4):297-303
The spread of lactic acid bacterial strains to the environment and to newborn piglets was investigated after feeding of such strains to sows. Rifampicin resistant bacterial strains were fed to sows, 10(10) c.f.u. per day, during the period from 1 week before expected farrowing until 1 week after farrowing. Fecal samples from the sows and samples of litter were collected for bacteriological examination together with swabs from the pens, the skin of the sows, and from the rectum of the piglets. The test strains were only excreted in relatively low amounts in the feces of the sows, approximately 10(3)-10(6) c.f.u. per gram. They were not able to displace the normal lactic acid bacterial flora in the sows nor were they transmitted to the intestinal tract of the piglets to any significant extent. After the last administration the test strains disappeared from both feces, skin, and environment, indicating that no permanent colonization had taken place, although considerable differences in duration of persistence were noticed between test strains. 相似文献
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为证明益生菌候选菌株具有益生特性,将筛选的鲤鱼源粪肠球菌YL-1进行体外抑菌试验。结果发现,YL-1对病原菌嗜水气单胞菌有较强的抑菌作用;通过对YL-1上清液进行热处理,蛋白酶处理,中和酸等方式分析发现,其抑菌物质主要是对有机酸和胰蛋白酶敏感的一类物质。 相似文献
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Enterococcus faecalis is a major cause of nosocomial infections in humans and has been linked to severe extra‐intestinal infections in poultry. A zoonotic potential has been suggested and the aim of the present study was to investigate similarities in virulence gene profiles of E. faecalis originating from infections in humans and poultry respectively. A total of 106 isolates of E. faecalis [26 human clinical isolates, 60 poultry clinical isolates (including two small‐colony variants (SCVs) and 20 poultry cloacal isolates] were investigated for presence of seven virulence‐associated genes: ace, asa1, cylA, efaA, EF0591, esp and gelE. For each gene, the PCR‐amplification product was sequenced from one isolate in each group to explore intragenic variations between genes of human and poultry origin. Haemolytic and protease activities were assessed and isolates were assigned a sequence type (ST). Three of the seven genes investigated (ace, efaA and gelE) were present in all isolates. The asa1 was detected in 63/80 and 13/26 isolates of poultry and human origin respectively. For cylA, the numbers were 46/80 and 14/26 respectively. Among poultry isolates, esp and EF0591 were the least frequently observed genes (1/80 and 20/80 respectively); the prevalences among human isolates were 1/26 and 18/26 respectively. A high degree of similarity between genes in human and poultry isolates were confirmed by sequencing of amplification products. None of the cylA‐positive isolates demonstrated haemolytic activity, while the phenotypic expression of gelatinase varied. The ST16 was the only ST shared by human and poultry isolates. The SCV isolates did not show a unique virulence profile or phylogeny. In conclusion, regardless of the distinct phylogenetic background of most E. faecalis isolates of human and poultry origin, we found major similarities in virulence gene profile and gene sequences in isolates from the two sources, supporting the zoonotic risk associated with this organism. 相似文献
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1株鹑鸡肠球菌产ESBLs和AmpC酶的基因型鉴定 总被引：1，自引：0，他引：1
为检测1株临床分离的七彩鸟鹑鸡肠球菌的ESBLs和AmpC酶的基因型,探讨其耐药基因的进化机制;采用两倍稀释法测定此菌株对18种常用药物的敏感性,并用9对特异性引物进行PCR扩增、基因克隆及测序分析,确定鹑鸡肠球菌ESBLs和AmpC酶的基因型及基因亚型.结果表明,鹑鸡肠球菌为产ESBLs和AmpC酶菌,除对3代、4代头孢,碳青霉烯类和磷霉素体外敏感外,对其他常用药物均呈现耐药,具有多重耐药特性;该菌所产 ES-BLs的TEM序列与AJ847364(TEM-116)序列相比发生了2处碱基突变,即512T→A和695A→C,引起了相应氨基酸的突变171Ile→Lys、232Lys→Thr,是一种新的TEM亚型,GenBank注册号DQ849329;AmpC酶与序列EF078894(ACT-like型)有97%的同源性,GenBank登录号是DQ849330.这表明该株鹑鸡肠球菌ESBLs为一种新TEM亚型,来源于同时分离的鹑鸡克雷伯菌TEM型的ESBLs;ACT型AmpC酶的存在可能与七彩鸟鹑鸡接触过β-内酰胺类药物有关. 相似文献
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屎肠球菌的特性及其在畜牧生产中的应用研究进展 总被引：2，自引：0，他引：2
随着对畜产品需求的增加,人们越来越重视畜产品的安全性。屎肠球菌为常见乳酸菌,是近年来研究较多的益生菌,其代谢产物对病原菌的抑制、肠道菌群稳定和家畜生长具有重要意义,已广泛应用于畜牧生产中,但耐药性和致病性屎肠球菌的相继发现,引发了公众的担忧。因此,如何合理、规范应用屎肠球菌是其在畜牧生产中应用的关键。本文综述了屎肠球菌的生物学特性及其在畜牧生产中的应用研究进展,但抗生素耐药性屎肠球菌的发现,使得屎肠球菌的应用更为谨慎。 相似文献
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从湖南各地送检至实验室的临床样本中分离到42株革兰氏染色阳性及过氧化氢酶阴性的球菌,其中78.6%来自于肺脏,菌落形态及染色镜检均与粪肠球菌参考株ATCC 29212相似,兰氏分群鉴定97.6%（41/42）为D群,生化特性符合粪肠球菌特征。16SrDNA测序鉴定显示：42个分离株与同步测序的ATCC 29212同源性在99.2%到100%之间,与所选择粪肠球菌参考序列的同源性在98.7%到100%之间,NCBI在线BLAST分析发现42株均与GeneBank收录的粪肠球菌序列同源性最高。湖南分离株16SrDNA序列与E.faecalis参考序列进化关系与地域分布无关,来源于不同宿主的菌株的16SrDNA变异并不大,而与E.faecium、E.canis、E.avium、E.hirae等4种肠球菌则有多处变异,这些变异区域在这4种肠球菌中却是保守的。 相似文献
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家蚕消化道来源蒙氏肠球菌的鉴定 总被引：1，自引：1，他引：0
研究了从家蚕消化道内分离出的4株肠球菌(C1、GC、FD、A20)的生理生化特征和16S rDNA序列,并与肠球菌种特异性探针序列进行了比较。生理生化特征测定结果表明,除A20外,C1、GC和FD与蒙氏肠球菌种的特征基本一致。由16S rDNA序列分析结果可知,分离菌株均与蒙氏肠球菌(Ent.mundtiiAJ301836)有高度同源性,在系统发育树内位于同一分支。分析肠球菌种特异性探针序列,分离菌株的16S rDNA含有与蒙氏肠球菌种特异性探针完全相同的序列。因此认为家蚕消化道内存在蒙氏肠球菌。 相似文献
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Herrero IA Teshager T Garde J Moreno MA Domínguez L 《Preventive veterinary medicine》2000,47(4):255-262
A study to estimate the prevalence of vancomycin-resistant Enterococcus faecium in faecal samples from pigs at slaughterhouses in Spain was carried out between November 1998 and January 1999 with 900 samples taken from four abattoirs representing 9.7% of all pig slaughtered in 1998. Using a selective enrichment broth with vancomycin (8 μg/ml), 64 samples (7.1%; 95% CI: 5.5, 9.0%) had E. faecium vancomycin-resistant strains that showed minimal inhibitory concentrations of 256 μg/ml (62 strains) and 512 μg/ml (two strains). Results by farm showed that 43 of the 240 pig farms represented in the sampling had at least one faecal sample with vancomycin-resistant E. faecium. 相似文献
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新疆北疆地区猪源粪肠球菌的耐药性分析 总被引：1，自引：1，他引：0
为了解新疆北疆地区猪源粪肠球菌的耐药性及相关耐药基因型的分布情况,本试验采用K-B（Kirby-Baller）琼脂扩散法检测了49株猪源粪肠球菌对8种抗菌药物的敏感性,并采用PCR法对9种相关耐药基因进行检测并测序,测序结果与GenBank中的相应基因序列比对。药敏试验结果显示,分离菌对链霉素耐药率最高,其次为青霉素和红霉素,对呋喃妥因、氨苄西林高度敏感。PCR检测结果显示,β-内酰胺类耐药基因tem的检出率最高,为93.88%,其次是四环素类耐药基因tetM,为85.71%,喹诺酮类基因gyrA和parC检出率均为42.86%,氨基糖苷类耐药基因aph（3'）-Ⅲ、aac（6'）/aph2″和ant（6'）-Ⅰ的检出率分别为36.73%、16.33%和16.33%,未检出mefA和ermB基因。本试验从表型与基因型分析发现,北疆地区猪源粪肠球菌的多重耐药现象非常严重,且其耐药表型与基因型并不完全一致。 相似文献