首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 15 毫秒
1.
1125 and 1146 E. coli strains isolated from suckling and weaned piglets with diarrhea, respectively, and 724 strains from healthy piglets were tested for the presence of fibriae and production of enterotoxins. The fimbriae were determined by hemagglutination and slide agglutination tests, enterotoxins—by the use of ileal loop test in piglets (LT and STb enterotoxins) and suckling mouse assay (STa enterotoxin). It was found that 72.8 and 53.0% strains, isolated from diseased suckling and weaned piglets, respectively, possessed specific fimbrial hemagglutinins, in most cases with K88 antigen. Additionally, 987P fimbriae were detected in 14.0 and 0.7% strains isolated from piglets with diarrhea. Only 5 strains (0.7%) recovered from healthy piglets had specific fimbriae, usually with undetermined antigenic structure. F1 fimbriae (called common or unspecific) were found in strains isolated both from diseased (15.2 and 16.3% strains, respectively) and healthy piglets (27.1% strains). It was noted that the strains isolated from suckling and weaned piglets with diarrhea in most cases were enterotoxigenic (90.5 and 69.1% strains, respectively) and most frequently produced heat-labile toxin LT alone or with STb. 18.5% of enterotoxigenic strains isolated from healthy piglets produced STa toxin.  相似文献   

2.
To study the occurrence and distribution of various strains of Haemophilus parasuis in southern Ontario swine, organisms isolated from healthy swine, from specific pathogen-free and conventional herds, and from disease cases were examined using restriction endonuclease fingerprinting analysis. In most herds, several strains of H. parasuis could be detected although one or two strains usually predominated. Individual animals were colonized by a single or limited number of strains. In several cases, the same strains were isolated from more than one specific pathogen-free herd. Conventional herds carried a more heterogeneous population of H. parasuis. Only one strain was isolated which was common to more than one conventional herd. No strains were isolated which were common to both specific pathogen-free and conventional herds. None of the strains isolated from disease cases were found in healthy conventional or specific pathogen-free swine examined in this study.  相似文献   

3.
Isolated acholeplasma laidlawii strains exhibited highly differentiated behaviours regarding their udder pathogenicity. Twelve of 16 tested strains were pathogenic to udder. Symptoms of acute udder inflammation were caused by all ten A. laidlawii strains isolated from differentiated material of calf, but by only two of six strains isolated from differentiated material of cattle. Intracisternal instillation of both strains from milk and one strain each from udder skin or cervical mucus caused merely temporary disorders of secretion. Ultrasonic extracts of A. laidlawii strains, some of them additionally heated, were intracisternally applied, as well. Udder irritation was caused only by those acholeplasma strains which were udder-patha was assumed to be attributable to a toxin of the polysaccharide type. Pathogenicity to udder was recorded also from one M. alkalescens strain isolated from a nose swab taken of cattle as well as from two A. granularum strains isolated from calf lungs.  相似文献   

4.
Vacuole response in HEp-2 cells was induced with culture supernatants of Bacillus cereus strains isolated from outbreaks of vomiting- and diarrheal-type food poisoning grown in rice flour and laboratory media. High vacuole response was obtained with culture supernatants of B. cereus strains isolated from vomiting-type food poisoning grown in cooked rice suspension or on a cooked rice plate, whereas no response was obtained with those of the same strains grown in brain heart infusion and trypto-soya broth media. The vacuole activity appeared only after spore formation of B. cereus. The activity was stable to proteolytic enzymes, heating, and exposing to pH 2.0 and 11.0. Of 124 strains isolated from B. cereus food poisoning that were tested, the vacuole activity was observed by 68 of 110 (61.8%) of the strains isolated from the vomiting-type food poisoning but not by all strains (14 strains) from diarrheal-type ones. Moreover, the vacuole response in the HEp-2 cells was found to be induced by 56 of 76 (73.7%) of the serotype H-1 strains isolated from vomiting-type food poisoning.  相似文献   

5.
为了解2009－2010年间在河南、甘肃地区分离鉴定的5株大肠埃希菌O157(E.coli O157)携带stx的情况及不同分离株间stx分子进化与变迁的情况,本研究利用PCR方法对分离株进行了stx基因检测,并完成了序列测定与系统演化分析。结果表明,5株不同动物源的分离株均含有stx1及stx2基因。序列分析结果显示5株分离株间stx1、stx2的核苷酸及氨基酸同源性均较高;stx1基因均与参考株中的山羊源和食品源E.coli O157菌株的同源性较高,进化树中遗传距离最近;分离株的stx2基因与多株牛源及少数人源参考株也具有较高的同源性,进化树中虽然5株分离菌均在一个大主干分支中,但分离株27与其他各分离株及参照株遗传距离最远,独自处于一次级分支中;分离株L37与W、12与50分别分布于牛源、人源E.coli O157小次级分支中;由此可推测,分离株所携带的stx1很有可能是经食品源或羊源E.coli O157传递而来;分离株L37与W、分离株12与50的stx2可能是由牛源、人源E .coli O157菌株传递而来,分离株27的stx2来源不清楚。研究结果表明,5株E.coli O157分离株均含有stx1、stx2基因,但两个基因的起源存在差异。  相似文献   

6.
A diarrhoeic syndrome in piglets has been linked to Clostridium perfringens type A because this organism has been isolated in large numbers from all cases. The strains isolated from these cases and strains isolated from healthy piglets were screened for the enterotoxin gene of C perfringens by DNA-hybridisation. Using two different synthetic DNA-probes, none of the strains isolated from diseased pigs was positive in this reaction, indicating that the enterotoxin of C perfringens is not involved in the syndrome.  相似文献   

7.
猪流感病毒的分离及NA基因的遗传进化分析   总被引：1，自引：1，他引：0  
通过鸡胚接种分离到3株猪流感病毒,经HI、RT-PCR鉴定,其中GXHZ株为H1N2亚型毒株,GXLZ、GXXY株为H3N2亚型毒株,并对分离株进行EID50测定及GXHZ株的猪体攻毒试验。所扩增分离到3株SIV病毒NA基因与A/Sw/Hainan/1/2005(H1N2)的核苷酸和氨基酸序列同源性最高。3株SIV分离株的NA基因在氨基端胞浆尾区均由K6→R6,在非极性跨膜区均由V20→M20。系统发育分析表明本试验所分离的3个SIV毒株与H1N2亚型毒株亲缘性最相近,且来源于猪源H1N2亚型流感病毒。从时间上也发现,3个分离株的NA基因与1996年以后获得的H3N2毒株亲缘关系很近,都隶属于一个亚分支。  相似文献   

8.
为科学评价河南省仔猪黄痢大肠杆菌地方分离株的耐药性和不同给药方法对仔猪黄痢疗效的影响,本研究首先自河南省25个临床发病猪场病猪体内分离鉴定仔猪黄痢大肠杆菌;通过小白鼠致病力试验以检测大肠杆菌分离株的毒力;采用20种抗菌药物对分离株进行药敏试验以筛选对仔猪黄痢大肠杆菌最敏感的药物;选取敏感药物分别采用口腔灌服、肌肉注射和腹腔注射3种给药方法对临床上仔猪黄痢发病猪进行治疗效果比较试验以确定最佳给药方法。结果自河南省25个发生仔猪黄痢的猪场的病猪体内共分离鉴定出25株大肠杆菌。25株大肠杆菌分离株对小白鼠的致病率为100%;对临床上常用的20种抗菌药物都有耐药现象,但耐药率高低不同(4%～100%);20种抗菌药物中诺氟沙星、氧氟沙星、新霉素和利福平等4种药物的敏感率较高,高敏率分别为92%、88%、88%和80%。3种不同的给药方法对仔猪黄痢病例的治疗效果不同,其中通过口腔灌服和腹腔注射的给药方法对仔猪黄痢的治愈率(分别为92.3%、95.0%)显著高于肌肉注射给药方法(58.8%);腹腔注射组治愈率稍高于口腔灌服组,但二者差异不显著。本研究为临床上仔猪黄痢的防制提供了科学依据。  相似文献   

9.
To determine the distribution of genes that encode enterotoxins A, B and C, 36 strains of Staphylococcus aureus isolated from goat mastitis and 64 isolated from bovine mastitis were analyzed by Multiplex PCR. Of the total strains studied, 37 (37%) were detected to have some of the SEs genes. From the bovine mastitis strains, 4 (6.3%) co-amplified the sea and seb genes and 2 (3.1%) were positive for the sec gene. From the goat mastitis strains, 31 (86%) tested positive to the Multiplex, and the sec gene was detected in all of them. The production of SE was detected in all strains harboring the corresponding gene. The results demonstrated that S. aureus isolated from goat mastitis had a higher enterotoxigenic potential than those isolated from bovine mastitis. Additionally, the presence of the sec gene in the majority of goat mastitis strains suggests a possible involvement of SEC in goat mastitis pathogenesis.  相似文献   

10.
Forty-nine strains of microaerophilic gram-positive cocci (Stuart-Schwan cocci) isolated from summer mastitis, "pyogenes"-mastitis, other pyogenic conditions of Danish cattle and swine, and from the sheep headfly Hydrotaea irritans were biochemically characterized with the API 50 CH and API ZYM test kit systems, and screened for production of a variety of extracellular enzymes by agar plate methods. For comparison 4 strains isolated from Swedish cases of heifer and dry cow mastitis were included in the study. Similarity calculations indicated a high degree of homogeneity within the strains studied (similarity level 92%; group mean similarity 87%). The strains probably represent one species, although the taxonomic position of the organism remains unclear. The biochemical feature of the strains studied were very similar for strains isolated from cases of summer mastitis and strains from other sources of origin. It is suggested that the Stuart-Schwan coccus occurs as a natural cohabitant to Actinomyces pyogenes, Peptostreptococcus indolicus and the anaerobic organism characteristic of the bacterial complex isolated from summer mastitis and similar pyogenic conditions in ruminants and swine.  相似文献   

11.
为鉴定分离自新疆北疆绵羊单核细胞增生李斯特氏菌,本研究采用多重PCR方法,鉴定来自病发地区部分羊场的发病绵羊、健康绵羊、羊舍环境和乌鸦粪分离的30株李斯特氏菌分离株的8株单核细胞增生李斯特氏菌分离株血清型。结果为4株发病绵羊株有3株鉴定为单核细胞增生李斯特氏菌,血清型为1/2a或4b,1株为非单核细胞增生李斯特氏菌;5株健康绵羊株血清型为1/2a;其余来自羊舍水源的3株、乌鸦粪的2株及健康绵羊16株为非单核细胞增生李斯特氏菌,表明来自发病绵羊、健康绵羊及参考菌株LM血清型之间具有相关性。  相似文献   

12.
Five strains of Leptospira interrogans isolated in the United Kingdom and belonging to the Pomona serogroup were subjected to cross-agglutination absorption and bacterial restriction endonuclease DNA analysis (BRENDA) for their identification. British isolates were compared with reference strains representing the known serovars in the Pomona serogroup and also with isolates of the Pomona serogroup obtained from other countries. Three strains isolated from wildlife in England produced equivocal results when the cross-agglutination absorption and BRENDA results were compared. According to the World Health Organisation definition of a serovar the three English strains represented two new serovars, whereas by BRENDA all three had DNA electrophoresis patterns indistinguishable from serovar mozdok. Serovar pomona has not as yet been isolated in Great Britain and the epidemiology of the Pomona serogroup infections that have been detected by serology suggests that a serovar such as mozdok, maintained by wildlife, may be the causal agent. Two strains isolated in Northern Ireland were identified as pomona by the cross-agglutination absorption test. Further studies are needed to investigate the homogeneity of field and reference strains that are designated as pomona using the cross-agglutination absorption test.  相似文献   

13.
Twenty-eight strains of Pasteurella multocida were isolated from 12 Danish and two Canadian abattoir pigs. Fourteen strains were isolated from pulmonary inflammatory lesions, and 14 strains were isolated from kidneys of the same animals. Phenotypical and genotypical characteristics of the strains were evaluated with a view to determine if P. multocida isolated from kidneys might have been disseminated from the lungs. All field strains were capsular type A. The biochemical reactivity in the API-20E and API-ZYM commercial test-kits was uniform with the exception of alpha-glucosidase activity which was present at low levels in only ten of the strains. One strain was markedly serum sensitive, six strains slightly sensitive and the remaining were serum resistant. The peptide patterns obtained by polyacrylamide gel electrophoresis of whole cell proteins of the strains were very uniform with the exception of differences in intensity of bands in the 38 and 34 kD regions. The pattern of oligonucleotides obtained after electrophoresis of total genomic DNA digested with BamHI showed that the paired isolates had identical patterns in eight of the 14 animals. It is therefore likely that isolates from kidney lesions represent blood borne dissemination from primary pulmonary lesions.  相似文献   

14.
Eighteen strains of Pseudomonas aeruginosa, i.e. 8.87%, were isolated during a year from 203 samples of raw milk. Two Pseudomonas aeruginosa strains, i.e. 4%, were isolated from 50 samples of pasteurized milk. The strains were isolated using propagation techniques in meat-peptone broth with malachite green and on selective media--on centrimide agar (CEM) and on Pseudomonas F agar. All the isolated strains produced protease, whereas lipase was produced by only five strains. The strains were devitalized when exposed to pasteurization temperatures (72 degrees C) for 20 seconds. At cold store temperatures (4 degrees C), Pseudomonas aeruginosa strain cells propagated on average by two orders, inhibitory effects of low temperatures were recorded only with one strain. Inhibitory effects of milk cultures (cream, yogurt) on Pseudomonas aeruginosa were observed; their effects were more clear-cut at the temperature of 4 degrees C. The strains were markedly susceptible to gentamycin.  相似文献   

15.
从新疆5个地区8个奶牛场乳房炎奶样中分离的101株β溶血性金黄色葡萄球菌中随机选64株用小鼠进行毒力测定,同时用随机引物扩增多态性(RAPD)技术分别以3个随机引物进行基因相关性分析,建立种系进化树。结果表明,55%的菌株对小鼠具有较强毒力(可致小鼠2/3死亡),且在乌鲁木齐、奎屯和伊犁地区占据优势。基因相关性分析表明,当相对基因相关性为0.35时,被检测菌株主要分布于6个进化群,86.5%的菌株分布在A、B、C和E4个进化群。其中,50%菌株属于A群,13.5%属于B群,5.8%属于C群,17.3%属于E群。从地区分布可见,乌鲁木齐、伊犁和奎屯地区分离的菌株分别有69.6%、61.1%和71.4%分布在A群;昌吉3个牛场48%、24%的分离菌株分布在B群和C群;库尔勒牛场35.7%、57.1%的分离菌株分布在A群和E群。26株对小鼠具有致死性的菌株分布在A群,这些菌株占致死小鼠菌株的74.3%。  相似文献   

16.
Klebsiella strains isolated from the cow and its environment were biochemically and serologically characterized and evaluated for their susceptibility to normal bovine serum. Thirty-one different biotypes of Klebsiella were identified among 288 cattle and environmental strains. Of these, 56.2% were indole-positive, a greater percentage than expected for Klebsiella. Biotypes 1/1/1 and 5/1/1, most frequently isolated and constituting about 37% of the total isolates, would be considered K pneumoniae by standard biochemical typing procedures. Of 65 cattle and environmental strains studied serologically, 11 serotypes, 14 biotypes, and 29 bioserotypes were identified, indicating the diversity of Klebsiella strains present in the herd. When strains from mastitic milk (n = 19) and the environment (n = 22) were compared, no bioserotype distinction or grouping that related to isolation source was obvious. The predominant bioserotype from both sources was 5/1/1-K35 (21.0% and 22.7% of the strains from mastitic milk and the environment, respectively). The growth inhibition by bovine serum of strains isolated from mastitic milk, the environment, and udder skin was similar. However, strains isolated from the mouth and rectum of the cow were significantly (P less than 0.05) more inhibited by serum.  相似文献   

17.
采用RT-PCR方法对2009—2011年山西省分离的5株猪繁殖与呼吸综合征病毒（Porcine reproductive and respiratory syndrome virus,PRRSV）的ORF5和Nsp2（2503～3269nt）基因进行克隆和测序,并对其基因序列和推导的氨基酸序列与国内外毒株进行了同源性分析。序列分析结果显示,5株分离株Nsp2基因与国内分离的PRRSV变异株（JXA1、HuN、HUN4、HUB1）的序列同源性最高,为96．8％～98．2％,且缺失位置一致,均存在2个位点30个氨基酸缺失;ORF5基因大小为603bp,编码200个氨基酸,第13、151位均为具有强毒特性的精氨酸（R）,137位为丝氨酸（S）,表明这5株均为野毒株,与国内分离的PRRSV变异株（JXA1、HuN、HUN4、HUB1）毒株的序列同源性最高,为96．5％～98．0％。结果表明,山西省内目前流行的PRRSV为Nsp2缺失30个氨基酸的变异毒株。  相似文献   

18.
从陕西杨凌某发病牛场采取腹泻犊牛病料5份,经微生物学诊断,从中分离出革兰阴性疑似致病菌6株。经生物学特性和生理生化试验鉴定,6株分离菌均为致病性大肠埃希菌。对分离菌进行抗生素敏感性试验,结果表明,该致病菌对氯霉素、菌必治、氧氟沙星、阿米卡星及卡那霉素等高度敏感;对妥布霉素、呋喃妥因和复达欣等中度敏感,对链霉素、庆大霉素、利福平、复方新诺明、四环素及红霉素等有较强的耐药性。动物致病性试验结果表明,该菌对小鼠有强致病性。  相似文献   

19.
《Veterinary microbiology》2015,175(2-4):312-318
Salmonella enterica subsp. enterica serovar Infantis strains were isolated from broiler chickens from six farms in Japan and the pathogenicity associated with the recently reported 280 kbp mega plasmid was examined by possession of the plasmid and histopathology of tissues from these chickens. S. Infantis strains were isolated from 10 of 24 chickens. Phylogenetic, network and Bayesian cluster analyses were used to determine whether these strains were in the previously defined Clusters 1–5. Phylogenetic analysis classified the strains isolated in this study in two groups (Groups A and B). Both groups contained strains from gastrointestional contents, but only Group A also contained strains from spleen, liver, and lymphoid tissues. Histopathology showed suppurative splenitis in a spleen from which Group A strains were isolated. Although network and Bayesian cluster analyses were unable to differentiate Group A and B strains from the previously defined Clusters 1–5, population genetic analysis indicated that Group A was a different population from Cluster 5, indicating that Group A would be a subpopulation of Cluster 5. The irp2 gene, which is in the mega plasmid carried by a pathogenic S. Infantis strain recently isolated in Israel, was found in both Groups A and B strains and in the previously reported Clusters 4 and 5 strains. These results suggested that Group A would be a novel subpopulation of the previously defined Cluster 5, and presence of the mega plasmid may not be related whether S. Infantis strains can infect certain organs.  相似文献   

20.
高静  郭旭生  王国成 《草业科学》2013,30(8):1266-1271
本研究以藏北嵩草（Kobresia littledalei）上附着的乳酸菌为研究对象，分离得到肠膜明串珠菌肠膜亚种两株，融合魏斯氏菌11株，食物魏斯氏菌6株，然后对这3种试验菌进行不同温度及pH条件下的生长试验、耐盐试验及糖发酵试验等生理生化特性的研究。结果表明，与常规条件下分离得到的相同菌株相比较，青藏高原极端环境中分离的魏斯氏乳酸菌和明串珠菌株都能在4~40 ℃的条件下生长，部分融合魏斯氏菌还可在50 ℃下微弱生长；耐酸碱试验表明，魏斯氏乳酸菌株都能在pH值为3.0和9.5的条件下生长；在耐盐性方面，部分魏斯氏菌可以在18%的NaCl下生长；在碳源利用方面，本研究提取的食物魏斯氏菌可利用半乳糖；融合魏斯氏菌可利用阿拉伯糖、蜜二糖、甘露醇。因此，藏北嵩草中所分离的乳酸菌比常规环境中的乳酸菌有较强的耐温性和耐酸碱性，而且能更广地利用碳源，从而为其在饲料青贮、酸奶发酵等方面的应用奠定基础。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号