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1.
《中国奶牛》2016,(5)
安全性评价是益生菌应用的前提,动物双歧杆菌KDB19是一株潜在益生菌,本研究对该菌株进行体外及体内的安全性评价,为菌株应用提供基础保障。通过体外试验评价了KDB19的抗生素抗敏感性和生物胺的生成;体内试验评价了KDB19的经口毒性及易位风险。结果表明,菌株KDB19不存在菌株特有的抗生素敏感性,排除了抗生素抗性横向转移的风险;经过在脱羧酶培养基中培养未发现该菌株产生生物胺;灌胃试验发现,将该菌株分别以10~8cfu/鼠、10~9cfu/鼠、10~(10)cfu/鼠剂量饲喂小鼠28d后,小鼠未发生不良反应,在其血液、肾脏、肝脏未发现该菌株;研究未发现菌株KDB19的不安全因素。 相似文献
2.
《中国奶牛》2015,(21)
本研究对益生菌菌株副干酪乳杆菌L9(Lactobacillus paracasei L9)进行了体外及体内的安全性评价。利用体外试验评价了L9的抗生素抗敏感性及生物胺的生成能力;体内试验评价了L9的经口毒性、正常状况下的易位风险及腹腔注射模拟的极端情况下的易位风险。结果表明,菌株L9不存在种属特有耐性以外的抗生素耐受性,不存在抗生素转移的风险;在脱羧酶培养基中培养未发现生物胺的产生;以108、109、1010 cfu/鼠灌胃28d,小鼠未发生不良反应,未发生向血液、肝脏、脾脏和肾脏的易位;109cfu/鼠腹腔注射发生易位现象,但未发生菌血症并且易位不会造成疾病或导致死亡,同时易位状况随时间有所缓解,表现为较高的易位安全性。试验结果证实副干酪乳杆菌L9具有较高安全性,可以直接应用于工业化生产。 相似文献
3.
《中国奶牛》2015,(15)
动物双歧杆菌A6是一株具有较强耐受性能的双歧杆菌菌株。本研究利用动物实验评价该菌株的缓解便秘作用。将Balb/c雄性小鼠随机分为空白组、模型组、A6不同剂量组。模型组、A6组使用复方地芬诺酯建立小鼠便秘模型,之后三组模型鼠分别给予低、中、高剂量(1×106、1×108、1×1010CFU/m L)的A6活菌液0.1m L/(kg·d),空白组和模型组灌胃0.1m L/(kg·d)(以体质量计)质量分数10%的脱脂乳。利用墨汁推进方法评价排便情况。动物双歧杆菌A6给药7d后,便秘小鼠首次排便时间缩短,排便粒数和质量明显增加,粪便水分含量提高;连续15d灌胃动物双歧杆菌A6,便秘小鼠小肠墨汁推进率也得到显著增加。结果表明,动物双歧杆菌A6具有良好的润肠通便功能。 相似文献
4.
《中国奶牛》2017,(6)
为评价益生菌对健康小鼠肠道发育的影响,选取三周龄Bal B/C雄性小鼠48只,随机分为6组:阴性对照生理盐水组、副干酪乳杆菌L9组、动物双歧杆菌A6组、长双歧杆菌BBMN68组、唾液乳杆菌FDB86组、阳性对照干酪乳杆菌代田菌株LcS组,以108cfu/mL水平每天0.2mL的剂量连续灌胃21d后处死,用免疫组化法对空肠的绒毛长度和隐窝深度,以及肠道上皮细胞的增殖(Ki67核抗原)、分化(MUC2黏蛋白)进行测定。结果表明,与阴性对照生理盐水组相比,副干酪乳杆菌L9对健康小鼠肠道形态发育的影响最显著,与阳性对照干酪乳杆菌代田菌株LCS组相比较,副干酪乳杆菌L9与阳性对照组试验结果相一致。结果表明,益生菌对健康小鼠的肠道形态发育有着重要作用,试验所用的四种益生菌中,副干酪乳杆菌L9对小鼠肠道的形态发育有着更显著的影响。 相似文献
5.
试验旨在评价1株从杜仲中分离的解淀粉芽孢杆菌的安全性。试验从菌株溶血性、氨基酸脱羧和明胶液化试验、抗菌药物敏感性、腹腔注射、经口灌胃、抑菌活性等进行安全性综合评价。腹腔注射试验分为腹腔注射组(1.0×1010 CFU/0.3 mL)和生理盐水组,一次性注射,连续观察5 d。经口灌胃试验分为高剂量组(1.0×1010 CFU/0.2 mL)、中剂量组(1.0×109 CFU/0.2 mL)、低剂量组(1.0×108 CFU/0.2 mL)和生理盐水组,每天灌胃1次,连续灌胃28 d。结果显示,腹腔注射和经口灌胃小鼠均健康存活,未见临床变化,试验期间体重正常增加,各组小鼠血常规、血清生化指标和脏器指数差异均不显著(P>0.05),解淀粉芽孢杆菌DZ01未发生易位,氨基酸脱羧和明胶液化试验均为阴性。解淀粉芽孢杆菌DZ01对所测的8种抗菌药物均表现敏感。除粪肠球菌和铜绿假单胞菌外,解淀粉芽孢杆菌DZ01上清液对其余6株指示菌均具有抑菌活性。研究表明,解淀粉芽孢杆菌DZ01具有较好的安全性。 相似文献
6.
《中国奶牛》2015,(21)
动物双歧杆菌A6是一株具有优良功能的益生菌。为了实现菌株的产业化应用,本研究对该菌株高密度发酵培养基进行了优化。以动物双歧杆菌A6的活菌浓度为评价指标,以MRS培养基为基础培养基,利用正交试验对培养基中氮源、促生长因子以及无机盐添加量进行了优化,确定活菌浓度最佳的培养基配方为:蛋白胨10.0g/L,酵母粉7.5g/L,牛肉膏5.0g/L,西红柿汁20g/L,葡萄糖20.0g/L,无水乙酸钠7.5g/L,七水合硫酸镁0.9g/L,一水合硫酸锰0.2g/L,柠檬酸氢二铵2.0g/L,磷酸二氢钾2.0g/L,吐温-80 1.0g/L,L-半胱氨酸盐酸盐0.5g/L。对优化完成的培养基进行50L发酵罐小试试验,结果表明动物双歧杆菌A6约在12h达到稳定期,菌体浓度可以达到6.0×109cfu/m L,与基础培养基培养结果(1.6×109cfu/m L)相比有显著的提高,具有实际应用价值。 相似文献
7.
《动物医学进展》2020,(9)
为评价分离自白蚁肠道的坚强芽胞杆菌-CX10(Bacillus firms-CX10)菌株的安全性,进行坚强芽胞杆菌-CX10菌株经口灌胃和腹腔注射的小鼠急性毒性试验,试验分为生理盐水正常组、低剂量组(1.5×10~4CFU/mL)、中剂量组(1.5×10~6CFU/mL)和高剂量组(1.5×10~8CFU/mL),分别连续灌胃和腹腔注射3 d,每天2次,7 d后处死小鼠剖检。结果表明,试验各组小鼠无中毒反应和死亡,小鼠的精神状态、食欲和行为等在一般健康等级中处于I级,剖检小鼠脏器均未见病变;低、中、高剂量组及对照组小鼠体增重、血液学指标、血生化指标以及脏器指数差异不显著(P0.05);对主要脏器进行病理组织切片观察,镜检结果显示,坚强芽胞杆菌-CX10对小鼠主要脏器均无明显致病理变化。由结果可知,白蚁源坚强芽胞杆菌-CX10菌株生物学特性良好,且对小鼠安全无毒,初步确定了菌株的安全性,对开发微生态制剂产品提供一定的参考。 相似文献
8.
为建立一种可以同时扩增大肠杆菌(E.coli)F4、F5、F6、F41和F18菌毛基因保守序列的多重PCR检测方法,本研究设计合成5对分别针对F4、F5、F6、F41和F18菌毛基因的特异性引物,以具有相应菌毛基因的E.coli参考菌株DNA为模板,通过对多重PCR反应条件的优化,建立了检测F4、F5、F6、F41和F18菌毛基因的多重PCR方法。所建立的多重PCR方法能够特异性扩增F4、F5、F6、F41、F18菌毛基因的目的片段,大小分别为770 bp、533 bp、422 bp、643 bp和1140 bp,该方法对沙门氏菌、猪丹毒杆菌、巴氏杆菌以及无菌毛基因的E.coli等参考菌株均无特异性扩增片段,检出F4、F5、F6、F41和F18菌毛基因的最低活菌浓度分别为5.3×10^5cfu/mL、3.7×10^6cfu/mL、3.1×10^5cfu/mL、3.7×10^7cfu/mL、6.9×10^5cfu/mL。用不同批次的引物和试剂进行3次多重PCR检测均能扩增出目的条带,表明建立的多重PCR方法有很好的批内和批间重复性。对90株大肠杆菌临床分离菌株菌毛基因进行检测,F4阳性率为3.33%,F5阳性率为2.22%,未检测到F6、F41和F18阳性菌株,其检测结果与常规单一PCR的检测结果一致。研究表明:建立的E.coli菌毛基因多重PCR分型方法具有很好的特异性、敏感性和重复性,可用于E.coli分离菌株菌毛基因型的快速鉴定,同时提高了检测效率。 相似文献
9.
《黑龙江畜牧兽医》2020,(16)
为了研究6株分离自四川省内江市2个养殖场患病山羊支气管的多杀性巴氏杆菌的主要生物学特性,试验采用特异性PCR方法鉴定多杀性巴氏杆菌血清型,采用纸片扩散法(Kirby-Bauer)评价了临床分离菌株对14种抗菌药物的敏感性,采用Reed-Muench法测定分离菌株对昆明小鼠的半数致死量(LD_(50)),分析其致病性。结果表明:在6株多杀性巴氏杆菌中,4株为A型,2株为B型。分离菌株对青霉素和林可霉素100%耐药,而对复方新诺明和氟苯尼考具有较高的敏感性。分离菌株对昆明小鼠的半数致死量均大于5×10~(8.0) cfu/0.5 mL,致病性较弱。说明本次分离的山羊源多杀性巴氏杆菌菌株为弱毒株,丰富了我国山羊源多杀性巴氏杆菌的生物学特征,为其感染的防控提供了有用的信息。 相似文献
10.
为检测不同动物源肠外致病性大肠杆菌(ExPEC)的耐药及致病性差异,本研究从132份鸡、猪和水貂等动物肠道外组织中分离鉴定大肠杆菌,并对分离菌株进行了16S rRNA基因测序、毒力基因检测、药敏试验、O抗原鉴定、系统进化群分析及动物致病性试验。实验结果显示:分离出53株ExPEC,且至少携带特异性毒力基因pap、sfa/foc、afa/dra、iutA、kpsMTII中的两种基因,并携带fimH、ibeA、hlyA、malX、iss、iroN等其它相关毒力基因。53株ExPEC分离株对氯霉素、卡那霉素、头孢噻吩、四环素、多粘菌素B、氨苄青霉素等呈现不同程度的多重耐药性;O抗原主要分布于O1、O2、O8、O11、O38、O78、O120血清型;系统进化群分析结果显示:28株属于A群,19株属于B1群,1株为B2群,5株属于D群。选取20株ExPEC分离菌株按照6×10~6cfu/只对小鼠进行腹腔注射,验证其致病性;并测定ExPEC6、ExPEC42、ExPEC52、ExPEC53菌株对BALB/c小鼠的LD_(50),其结果分别为3.49×10~6cfu/mL、9.49×10~5cfu/mL、9.48×10~6cfu/mL、2.38×10~7cfu/mL。本研究为动物源性ExPEC的预防诊断提供依据,并为下一步研究其致病机理等奠定基础。 相似文献
11.
以减毒沙门氏菌为载体的GM-CSF与生长抑素DNA疫苗的安全性和稳定性 总被引：1，自引：0，他引：1
将含GM-CSF基因与生长抑素(SS)的融合真核表达质粒pGM-CSF/SS转入减毒沙门氏菌株CS022。选择40只22~24 g的雌性小鼠,随机分成4组,其中1组为对照组,口服生理盐水;2~4组为试验组,分别用上述重组减毒沙门氏菌株CS022以108、109、1010CFU的剂量口服免疫小鼠,2周后以相同的剂量加强免疫,研究pGM-CSF/SS真核表达质粒在体内的稳定性和减毒沙门氏菌对小鼠的安全性。同时通过体外传代,研究该真核表达质粒在体外的稳定性。结果表明:108、109CFU剂量口服小鼠,成活率达100%,而1010CFU剂量口服小鼠成活率降低至90%,腹泻率达50%。体外传10代和口服免疫4周后从小鼠肝脏和脾脏分离的减毒菌用琼脂糖凝胶电泳和酶切鉴定法证实,减毒菌中的重组质粒在体外和侵入小鼠体内过程中具有较好的稳定性。质粒DNA在传10代以后,虽然每代的质粒DNA含量有些变化,但总体趋势基本是恒定的,第10代时,质粒DNA的含量与第1代的含量差异不显著。上述结果提示,利用该减毒沙门菌作为载体传递pGM-CSF/SS DNA疫苗免疫小鼠具有相对安全性和稳定性,为进一步有效激发机体的免疫应答提供了前提。 相似文献
12.
Oral-vaccine microspheres based on formalin-inactivated Actinobacillus pleuropneumoniae serotype 1 (AP-1) antigens and enteric-coated polymers were prepared using a co-spray drying process. We evaluated using this for a peroral vaccine. We measured specific-antibody titers and protection from challenge in mouse and pig models. In mice (24 per group), a subcutaneous aluminum-adjuvant vaccine or oral vaccination with three doses of AQ6-AP microspheres provided similar protection against intranasal challenge with 5 x 10(8) colony-formation units (cfu) of AP-1 bacterial culture broth. Two weeks after four oral vaccinations with 600 mg of AQ6-AP microsphere acetate solution (containing formalin-inactivated AP-1 antigens of 1.0 x 10(10) cfu bacterial broth), pigs (9 per group) were challenged intranasally with 1 ml of AP-1 bacterial culture broth (5 x 10(9) cfu). The clinical signs, percentage of pig survival ratio, lung lesion areas, and microscopic examinations indicated that the oral AQ6-AP vaccine provided more protection than vaccinating pigs intramuscularly with AP-1 aluminum vaccine. 相似文献
13.
C Bogni M Segura J Giraudo A Giraudo A Calzolari R Nagel 《Canadian journal of veterinary research》1998,62(4):293-298
An avirulent mutant, designated RC122, was derived from Staphylococcus aureus bovine mastitis strain RC108 after N-methyl-N'-nitro-N-nitrosoguanidine mutagenesis. Mutant RC122, which was isolated on the basis of reduced colony size, showed diminished virulence in mice (LD50 of RC122: 3.1 x 10(10) cfu vs LD50 of RC108: 2.3 x 10(7) cfu). Mutant RC122 grew more slowly than its parental strain and showed decreased production of several exoproteins, such as alpha- and beta-hemolysin, DNAse and coagulase. The production of its capsule was induced only under in vivo growth conditions. Clearance studies performed in the mouse kidney revealed that the kinetics of disappearance of the mutant was similar to that of its parental strain. Protection experiments carried out by intraperitoneal administration in mice showed that mutant RC122 conferred a good degree of protection from challenge with homologous and heterologous strains. 相似文献
14.
通过紫外诱变和硫酸二乙酯诱变,筛选出抗生素抗性(头孢氨苄和氨苄西林)的保加利亚乳杆菌,同时模拟人体胃酸环境(pH1.5～4.5)和十二指肠高胆酸盐环境(0.1g/100mL～0.4g/100mL)对诱变后的保加利亚乳杆菌的抗性进行了研究。结果表明,保加利亚乳杆菌突变株可抗头孢氨苄和氨苄西林(均为2mg/mL),并且在pH2.5～4.5时具有较强的生存能力,培养4h活菌数仍达108cfu/mL以上,在pH1.5条件下仍有部分存活。在0.1g/100mL～0.3g/100mL胆酸盐条件下培养4h,活菌数仍达106cfu/mL以上,且能在0.4g/100mL胆汁盐中存活。 相似文献
15.
试验选用200只1日龄海蓝褐蛋雏鸡,分为6个组,每组30只,对照组饲喂基础日粮,试验组在基础日粮的基础上分别添加10^7du／g益生素,300mg／kg黄芪多糖,30mg／kg酵母多糖,5×10^6cfu／g益生素＋150mg黄芪多糖和5×10^6cfu／g益生素＋15mg酵母多糖,试验周期50d。试验结果表明：益生素和多糖均能提高雏鸡的生长性能,免疫器官指数和抗体滴度和血清溶茵酶含量,而以益生素＋黄芪多糖组效果最好,而益生素＋酵母多糖组在本次试验中则没有体现出复配优势。 相似文献
16.
Boyen F Pasmans F Van Immerseel F Morgan E Botteldoorn N Heyndrickx M Volf J Favoreel H Hernalsteens JP Ducatelle R Haesebrouck F 《Veterinary microbiology》2008,128(3-4):364-373
Virulence genes regulated by the SsrA/B system are indispensable for systemic disease in BALB/c mice. The role of this regulating system in the pathogenesis of Salmonella Typhimurium infections in pigs is not documented. In the present study, the interactions of Salmonella Typhimurium and an ssrA/B mutant were compared in vitro and in vivo. The ssrA/B mutant strain displayed decreased Salmonella Pathogenicity Island 2 (SPI-2) expression levels, showed a replication defect in mouse macrophages and was attenuated in a mouse model after oral inoculation. Using real time qRT-PCR and a porcine ileal loop model, it was shown that the ssrA/B mutant strain was not significantly attenuated in overall virulence and SPI-1 expression in specific. Flowcytometric analysis demonstrated that the ssrA/B mutant strain was defective in intracellular replication in porcine macrophages. After oral inoculation of piglets with the wild type strain or the ssrA/B mutant strain, the animals of both groups excreted Salmonella and were colonized by Salmonella to the same extent. In an intravenous mixed infection model, the ssrA/B mutant strain was defective in the colonization of several internal organs. These results suggest that the ssrA/B gene of Salmonella Typhimurium plays a limited role in the persistent intestinal colonization of pigs. 相似文献
17.
The studies reviewed here evaluated the role cellular immune system components play in control of brucellosis by conducting comparative studies with brucella-resistant C57BL/10 or C57BL/6 mice and susceptible BALB/c mice. We have shown by both in vitro and in vivo studies that activation of macrophages with interferon-gamma (IFN-γ) is an important factor for control of infection with B. abortus in the mouse model and that the mechanism of anti-brucella activity largely involved reactive oxygen intermediates. Differences in control of the organism by resistant and susceptible mice was not related to inherent differences in the ability of their macrophages to control infection either with or without IFN-γ activation nor was it attributable to NK cells since we found no role for them in control of brucellosis in either mouse strain. However, relative resistance to brucellosis did correlate with increased production of IFN-γ by CD4 T cells during the first weeks after infection while IL-10 contributed to susceptibility in BALB/c mice. Moreover, by 3 weeks post-infection splenocytes from the susceptible BALB/c mice failed to produce IFN-γ and relied on TNF- as well as CD8 T cells to control infection until the end of the plateau phase around 6 weeks post-infection when IFN-γ production resumed and clearance began. In contrast, IFN-γ was crucial for control throughout the infection in the more resistant C57BL/6 mice and the mice died in its absence by 6 weeks post-infection compared to 12 weeks for the more susceptible mice that relied on additional mechanisms of control. In contrast to the IFN-γ knock-out mice, both β2 microglobulin knock-out C57BL/6 mice, which do not express conventional MHC class I molecules and thus cannot present antigen to CD8 T cells, or perforin knock-out C57BL/6 mice, which have no T cell cytotoxic activity, controlled and cleared the infection as well as normal C57BL/6 mice. The hiatus of IFN-γ production in BALB/c mice correlated with very high levels of total IL-12 and it was postulated that the lack of IFN-γ was a consequence of p40 homodimer blocking activity. However, reduction of p40 IL-12 in vivo through administration of indomethacin reduced the infection without a concomitant measurable increase in IFN-γ. Current studies are aimed at elucidating the mechanism of the IFN-γ hiatus. 相似文献
18.
开发了用家蚕蛹表达的人粒细胞-巨噬细胞集落刺激因子(rhGM-CSF)的口服药物。试验评价了猕猴、大鼠和小鼠口服rhGM-CSF毒性情况,包括遗传毒性、单剂量和重复剂量的全身毒性以及生殖毒性。毒理学试验显示:静脉给药在NIH小鼠中最大耐受剂量为3 300μg/kg,LD50为2 020μg/kg,在SD大鼠中LD50为3 660μg/kg。在猕猴和大鼠的重复剂量毒性试验结果中显示:口服rhGM-CSF后,除了雌性SD大鼠的血糖含量外,其余各项指标包括白细胞、红细胞、血红蛋白含量、血小板数量以及血细胞凝集等都正常。雌性大鼠每天口服剂量为1 250μg/kg时,给药后血糖浓度显著增加(P<0.001),但在恢复期间可恢复到正常水平。微核实验、CHL染色体畸变试验和埃姆斯测验法都表明无论是在体内还是体外服用rhGM-CSF均未见遗传毒性,普通的生殖毒性试验和围产期及致畸敏感期的毒性试验均未见异常现象,表明口服rhGM-CSF无明显生殖毒性。临床前毒性试验表明口服超过临床剂量10倍的rhGM-CSF与严重的慢性中毒没有联系,其在药理学有效剂量的范围内是很安全的。 相似文献
19.
AIMS: To study the adhesion properties of a biotype 4, serotype O:3 (human pathogenic) strain of Yersinia enterocolitica and to determine if adhesion in vitro and colonisation in vivo can be prevented by competition with a biotype 1A, serotype O:6,30 (non-pathogenic) strain. To study interaction between Y. enterocolitica biotype 4, serotype O:3 and cultured epithelial cells using the synthetic tripeptide arginine-glycine-aspartic acid (RGD). METHODS: The human intestinal epithelial (HEp-2) cell line was used for in vitro studies. Inocula of Y. enterocolitica biotype 4, serotype O:3 radiolabelled using tritium were incubated with HEp-2 cells and RGD tripeptide, or with Y. enterocolitica biotype 1A, serotype O:6,30 sequentially or concurrently, then washed and lysed, and radioactivity measured to determine the effect of RGD on adhesion, and competitive exclusion of pathogenic by non-pathogenic bacteria. For in vivo studies, two groups of 5-week-old piglets (n=5/group) were sequentially inoculated orally with 5 x 10(9) colony forming units (cfu) of either a non-pathogenic biotype 1A, serotype O:6,30 strain of Y. enterocolitica followed by a pathogenic biotype 4, serotype O:3 strain, or vice versa. Pigs were monitored for carriage of strains using bacterial culture and a multiplex polymerase chain reaction (PCR). RESULTS: The RGD tripeptide significantly inhibited adherence of the pathogenic Y. enterocolitica strain to cultured epithelial cells, suggesting that adhesion involved the RGD tripeptide sequence. The non-pathogenic biotype 1A, serotype O:6,30 strain of Y. enterocolitica prevented adhesion of the pathogenic strain to cells in vitro when allowed to adhere first. Pathogenic Y. enterocolitica was consistently isolated from rectal swabs from 80-100% of pigs on all sampling occasions but not from oral swabs after 14 days in pigs first inoculated with the non-pathogenic strain or at 26 days in pigs first inoculated with the pathogenic strain. CONCLUSIONS: A non-pathogenic strain of Y. enterocolitica reduced adhesion of a human pathogenic strain in vitro but not in vivo. 相似文献
20.
The adhesive capacity of selected enterococci to human, canine and porcine intestinal mucus was investigated in order to select for potential probiotic strains with good adhesive properties for human or animal use. The adhesion to the human intestinal mucus of the tested strains was found to range from log10 3.8 to log10 8.6 cfu per microtitre plate well. The highest adhesion to the human intestinal mucus was found among strains from horse faeces, dog faeces and dog feed. The adhesion to canine mucus was observed to range from log10 3.8 to log10 8.3 cfu/well, with the highest adhesive capacity among strains from dog faeces, horse faeces and dog's feed; on average log10 7.9, 7.3 and 7.0 cfu/well, respectively. Isolates from dogs did not bind at higher levels to canine mucus than to human mucus. A strong correlation was observed for the adhesion to human and canine intestinal mucus (p < 0.0001) and also between porcine and canine or human mucus (p < 0.05 for both). When comparing the adhesion of Enterococcus faecium and E. faecalis, no statistical significant differences were observed for any of the tested mucus types. The tested Enterococcus strains were found to exhibit a strain dependent on in vitro adhesion to human, canine and porcine intestinal mucus and did not exhibit host specificity in their adhesion, though some sources appeared to contain more adhesive strains than others. To our knowledge, this is the first report on the in vivo adhesion to intestinal mucus of a large number of enterococci from different sources. 相似文献