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1.
Wooley RE Ritchie BW Currin MF Chitwood SW Sanchez S Crane MM Lamberski N 《American journal of veterinary research》2001,62(9):1399-1401
OBJECTIVE: To determine whether an inactivated culture of a microcin-producing avian Escherichia coli was capable of killing Salmonella isolates from reptiles in an in vitro test system. SAMPLE POPULATION: 57 Salmonella isolate from reptiles. PROCEDURE: A wild-type avian E. coli electrotransformed with a plasmid coding for the production of microcin 24 was tested in an in vitro microassay system for its ability to kill 57 Salmonella spp isolated from reptiles. The reptile population included snakes, iguana, frilled lizards, turtles, other lizards, and unspecified reptiles. RESULTS: 44 of the Salmonella isolates were inhibited strongly, compared with the in vitro assay controls; 12 had weak inhibition, and 1 was not inhibited by the microcin-producing E. coli. Thirteen of the 57 isolates had resistance to at least 1 antibiotic, primarily streptomycin. There were 9 O serogroups identified in the 57 isolates, with serogroup H being the most prevalent (18 to 57). CONCLUSION AND CLINICAL RELEVANCE: Antibiotics are not recommended to eliminate Salmonella organisms from reptiles because of the development of antibiotic resistance. Further studies are necessary to determine whether the use of microcin-producing bacteria will be effective in controlling Salmonella infections in companion reptiles. 相似文献
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Frana TS Carlson SA Rauser DC Jones BD Fergen BJ Griffith RW 《American journal of veterinary research》2004,65(12):1616-1620
OBJECTIVE: To investigate the effect of an Escherichia that produced microcin 24 (Mcc24) on shedding of of Salmonella enterica serotypeTyphimurium in swine and evaluate evidence of in vivo activation of the Mcc24-mediated, multiple-antibiotic resistance (mar) operon. ANIMALS: 36 crossbred weaned pigs. PROCEDURE: 24 pigs were allocated to 2 groups (12 pigs/group). Pigs in 1 group received daily oral administration of an Mcc24-producing E coli, whereas the other group received a non-Mcc24-producing E coli. All pigs were challenge exposed with Salmonella Typhimurium chi4232. A third group of 6 pigs received Mcc24-producing E coli and was challenge exposed with an Mcc24-sensitive, marA-deleted strain of Salmonella Typhimurium 4232. After challenge exposure, fecal samples from all pigs were cultured to detect shedding of Salmonella Typhimurium and Salmonella Typhimurium isolates were screened for resistance to ciprofloxacin. Fecal samples were collected throughout the study, and tissue samples were collected during necropsy. RESULTS: Differences in shedding of Salmonella Typhimurium were not detected between groups receiving Mcc24-producing or non-Mcc24-producing E coli. No significant differences were found in quantitative analysis between groups receiving Mcc24-producing and non-Mcc24-producing E coli. Evidence of mar activation was not detected. CONCLUSIONS AND CLINICAL RELEVANCE: Microcin-producing E coli did not exert an effect on shedding of SalmonellaTyphimurium or mar activation in pigs. It may be difficult or impractical to create the conditions required for Mcc24 to be an effective part of a food safety intervention to reduce shedding of Salmonella Typhimurium. 相似文献
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Cecal samples from 100 broiler flocks were cultured for Escherichia coli and Salmonella. Samples were selected from flocks classified as either "good" or "poor" producers by a production formula. In an attempt to identify predictors of flock productivity, isolates were studied for differences in antibiotic resistances, hemagglutination of erythrocytes, production of colicins, production of siderophores, type of hemolysis, resistance to host complement, and presence of plasmids. S. typhimurium (copenhagen) was isolated from one poor producing flock and three good producers. Salmonella isolates showed no significant differences in the parameters studied. The E. coli isolates showed significant differences only for the presence of plasmids. These data indicate that differences in host intestinal E. coli from good and poor producing flocks do not predict flock productivity. 相似文献
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为了研究黄芪提取物对金黄色葡萄球菌、大肠杆菌和沙门氏菌等致病菌的抑菌活性,采用试管二倍稀释法,测定黄芪提取物对金黄色葡萄球菌、大肠杆菌和沙门氏菌的体外抑菌活性;采用相同浓度致病菌灌胃小鼠后,分别用黄芪提取物灌胃治疗,测定小鼠十二指肠、空肠、回肠和盲肠中肠道菌群数量,以确定黄芪提取物的体内抑菌活性.结果表明,无论是在体外还是在体内,黄芪提取物对金黄色葡萄球菌、大肠杆菌和沙门氏菌均具有抑制作用,对大肠杆菌的抑制作用最强,对沙门氏菌的抑制作用最弱;且通过灌注黄芪提取物,显著降低了各种致病菌致病后小鼠的死亡率.通过研究可以得出,黄芪提取物对常见的金黄色葡萄球菌、大肠杆菌和沙门氏菌等致病菌具有较明显的体内外抑菌作用. 相似文献
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In the Danish Salmonella Control Program, eggs from broiler parent flocks are surveyed by serologic analysis every 4 wk for antibodies against Salmonella lipopolysaccharide O-antigens 1, 4, 5, 9, and 12 (Mix-enzyme-linked immunosorbent assay [ELISA]) and 6 and 7 (Infantis-ELISA). The antibody response is measured in percentage optical density (OD%) of a strong positive reaction, and the cutoff value has been determined to be 40 OD%. Two or more reactors above 40 OD% will place the parent flock under suspicion. There has been concern about possible cross-reactions between Salmonella spp. and other Enterobacteriaceae, e.g., Escherichia coli, because a high specificity of a Salmonella antibody test is desirable. Moreover, false-positive Salmonella results have economic consequences and impede planning the production. A case-control study based on cases of clinical E. coli infections (colibacillosis) from two Danish hatcheries, supplying about 62% of the Danish broiler production, is described. In order to eliminate a possible bias from age and season, the controls were matched on age of the birds and on time of submitting the samples. This study shows that flocks with preceding colibacillosis did not have higher salmonella reactions than matched flocks without a preceding colibacillosis. This observation was confirmed in longitudinal studies. 相似文献
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鼠伤寒沙门菌鞭毛蛋白FliC的原核表达及其对口蹄疫疫苗的佐剂作用 总被引：1，自引：0，他引：1
用PCR扩增鼠伤寒沙门菌基因FliC,将PCR产物克隆至pMD18-T载体中,构建了克隆质粒pMD18-FliC。克隆质粒和pET-his载体用EcoR/Nhel双酶切,将得到的纯化基因FliC亚克隆至pET-his内,构建重组质粒pET-his-FliC。酶切、测序鉴定后,分别将重组质粒转染大肠杆菌BL21,经IPTG诱导表达,菌体蛋白超声处理,上清液用AKTA Explorer蛋白纯化系统纯化。用SDS-PAGE分析所得蛋白,发现于约53 000处出现了与目的蛋白一致的外源蛋白带。293-mTLR5细胞活性检测表明该融合蛋白能刺激TLR-5通路,引起NF-κB的活化。用小鼠模型检验FliC对O型口蹄疫抗原的免疫增强作用,证明其对口蹄疫疫苗具有佐剂作用。 相似文献
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The prevalence of verocytotoxin-producing Escherichia coli and antimicrobial resistance patterns of nonverocytotoxin-producing Escherichia coli and Salmonella in Ontario broiler chickens. 
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下载免费PDF全文 R J Irwin S A McEwen R C Clarke A H Meek 《Canadian journal of veterinary research》1989,53(4):411-418
The prevalence of verocytotoxin-producing Escherichia coli and Salmonella in Ontario broiler chickens was determined by culturing cloacal samples from 500 individual birds selected from 50 poultry farms. Resistance to antimicrobials was determined for each of the isolates. In addition, abattoir and farm-level management data were obtained to evaluate variables that may be considered risk factors for infection. The variables selected included: Percentage of birds condemned at slaughter, percentage of birds dead-on-arrival, bird weight, truck number, farm size, hatchery source, litter source and type, feed source, mortality levels, type of water drinker, water sanitization, down time, barn clean out and history of antibiotic treatment. None of the cloacal samples revealed the presence of verocytotoxin-producing E. coli, though 19/500 (3.8%) contained Salmonella organisms. Nine different Salmonella serotypes were isolated; the most common being S. hadar, S. heidelberg and S. mbandaka. Resistance to tetracycline and streptomycin was common among Salmonella (63%) and E. coli (25.2%) isolates. Resistance to two or more antimicrobials occurred in 420/500 (84%) of the E. coli isolates. No statistically significant associations between abattoir or farm-level management variables and the Salmonella-status of farms were demonstrated. 相似文献
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《动物营养（英文）》2015,(3)
The aim of this work was to compare the efficacy of a commercially available phytogenic feed additive(PFA) and an antibiotic growth promoter, which was bacitracin methylene disalicylate(BMD), on performance, nutrient retention, caecal colonization of bacteria and humoral immune responses against Newcastle disease in broiler chickens challenged orally with Salmonella enteritidis and Escherichia coli.One-day-old male Cobb 400 broiler chicks(n = 120) were fed with 1) a negative control(NC) diet, which is the basal diet without any added growth promoter, 2) a positive control(PC) diet, the basal diet supplemented with BMD, 500 mg/kg and 3) a diet supplemented with PFA(150 mg/kg) for 39 days and the birds were inoculated with S. enteritidis and E. coli on d 28. Supplementation of PFA improved body weight, feed conversion ratio, retention of N and crude fiber, increased fecal moisture content and decreased digesta transit time as compared with the NC and PC groups(P 0.01). Both the PC and the PFA was found to be equally effective in controlling the surge in numbers of Salmonella and E. coli following oral inoculation of these bacteria as compared with the NC group(P 0.05) at 24 h past inoculation. Caecal content analysis on d 39 indicated lower numbers of Salmonella, E. coli and Clostridium in the PC and PFA groups as compared with the NC group(P 0.05). The number of Lactobacillus in the PFA group was higher than those in the NC and PC groups(P 0.05). Humoral immune response,measured as hemagglutination inhibition titer against Newcastle disease, was better in the PC and PFA groups compared with the NC group(P 0.05) at d 21 but the difference did not last till d 39. The heterophil to lymphocyte ratio was narrower(P 0.001) and alkaline phosphatase activity was higher(P 0.01) in the PFA group as compared with the NC and PC groups on d 39. It was concluded that the PFA, which is animal, environment and consumer friendly, may be used as an effective replacement for common in-feed antibiotics like BMD to enhance broiler performance especially when the birds are exposed to heavy infections on fields. 相似文献
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DING Xiao-li CHEN Lin HUANG Dong-zhang LIU Jun-dong WEI Dong-xia GUAN Yuan-hong LI Ju-yin ZHOU Si-si CHEN Xin-xiu 《中国畜牧兽医》2013,40(10):216-220
To study the transfer mode of rmtB and armA in chicken intestinal E.coli,plasmid conjugation experiment was carried out to study the horizontal transfer mode of rmtB and armA genes, and conjugative transfer frequencies were calculated. Broth microdilution method was applied to test susceptibility of 16S rRNA emthylase-positive isolates and their transconjugants to antimicrobial agents. As a result, all the rmtB genes located in five rmtB-positive isolates were easily transferred to recipients of E.coli C600. Conjugative transfer frequencies varied from 4.30×10-10 to 5.5×10-6 per recipient cell, and the armA gene located in one armA-positive isolate was not easily transferred to the recipient of E.coli C600. The results suggested that horizontal transfer was responsible for the dissemination of rmtB gene in chicken intestinal E.coli, but not for armA. 相似文献
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为探究甘肃省民勤县某饲养场肉仔鸡腹泻的病原及复方中草药制剂和抗生素分别对分离病原的抑菌效果,对7日龄病死肉鸡进行解剖，通过采集死亡肉仔鸡肝脏、脾脏、心脏进行病原菌分离培养、形态观察、16S rDNA分子鉴定，最终鉴定该病死肉仔鸡为大肠杆菌与沙门氏菌混合感染。抑菌结果显示，复方中草药对分离得到的大肠杆菌、鸡白痢沙门氏菌、鸡副伤寒沙门氏菌均有良好的抑菌效果。10种抗生素药敏试验结果显示，此三株菌同时对氨苄西林、环丙沙星、四环素、恩诺沙星四种药物耐药；鸡大肠杆菌对庆大霉素、阿米卡星敏感，鸡白痢沙门氏菌对链霉素、氟苯尼考、头孢噻肟敏感，鸡副伤寒沙门氏菌对头孢曲松、链霉素、头孢噻肟敏感。上述研究结果为肉仔鸡大肠杆菌与沙门氏菌混合感染的分离鉴定以及科学指导用药提供参考。 相似文献
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采用药敏纸片法分别对香椿皮水煎液及乙醇处理后的水煎液、臭椿皮水煎液及乙醇处理后的水煎液进行了体外抑菌试验,结果显示：香椿皮水煎液及乙醇处理后的水煎液对大肠杆菌C83902、沙门氏菌C500、葡萄球菌CAU0183的最小抑菌浓度为0.125g.mL-1,对大肠杆菌K88分离株的最小抑菌浓度为0.25g.mL-1;臭椿皮水煎液及乙醇处理后的水煎液对大肠杆菌C83902、大肠杆菌K88分离株、沙门氏菌C500无抑菌作用,对葡萄球菌CAU0183有一定的抑制作用,最小抑菌浓度为0.25g.mL-1。 相似文献
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The purpose of the present study was to examine the effect of apramycin sulphate on the colonization of pathogenic E. coli in the intestines of chicks. Apramycin treatment (0.5g/l in the drinking water) of 3-to 5-week-old Leghorn chicks for 24 or 48 hours resulted in a reduction, to an undetectable level, in the number of coliforms in the digestive tract for at least the first 24 h. Per os inoculation of E. coli (O2:K1) after 24 to 48 h of treatment resulted in a significant decrease in colony forming units (cfu) in the digestive tract of the treated chicks. Food deprivation from the time of inoculation did not significantly change the results. However, food and water deprivation caused bacteraemia in a number of the control chicks but not in the treated chicks. Comparison of the level of protection between Leghorn and broiler (Anak strain) chicks revealed that there was a significantly higher (P<0.05) level of bacteraemia in the broiler than in the Leghorn chicks. Chicks treated with 0.25 g/l or 0.125 g/l apramycin for 24 or 48 h before E. coli inoculation showed significantly lower cfu in the colon and caecum than untreated control chicks, but significantly higher cfu were found in the colon than in chicks treated with 0.5 g/l apramycin. Although in vitro preincubation of apramycin with ileum cells did not decrease the percentage of cells to which the bacteria adhered, the number of bacteria adhered per cell decreased significantly. Taken together, our in vitro and in vivo results show that apramycin is effective against E. coli by preventing colonization of the gut by the bacteria, which could lead to a reduction of colibacillosis in poultry. 相似文献
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Edrington TS Callaway TR Bischoff KM Genovese KJ Elder RO Anderson RC Nisbet DJ 《Journal of animal science》2003,81(2):553-560
Escherichia coli O157:H7 and Salmonella are widely recognized as important agents of foodborne disease with worldwide distribution. The use of ionophores in feeding growing ruminants is widespread in the United States and has attracted recent interest due to the apparent temporal relationship between initial ionophore use and the increase in human E. coli O157:H7 cases. Two experiments were conducted to evaluate the effects of short-term feeding of ionophores on fecal shedding, intestinal concentrations, and antimicrobial susceptibility of E. coli O157:H7 and S. typhimurium in growing lambs. Sixteen lambs were used in each experiment, four lambs per treatment group: monensin, laidlomycin propionate, bambermycin, and a control treatment. Lambs were fed a grain and hay (50:50) diet with their respective ionophore for 12 d before experimental inoculation with E. coli O157:H7 or S. typhimurium. Animals were maintained on their respective diets an additional 12 d, and fecal shedding of inoculated pathogens was monitored daily. Lambs were killed and tissues and contents were sampled from the rumen, cecum, and rectum. No differences (P > 0.05) in fecal shedding of Salmonella or E. coli O157:H7 were observed due to treatment. Occurrence of Salmonella or E. coli in luminal contents and tissue samples from the rumen, cecum, and rectum did not differ (P > 0.05) among treatments. Feeding monensin decreased (P < 0.05) the incidence of scours in sheep infected with Salmonella compared with the other treatments. No differences in antimicrobial susceptibility were found in any of Salmonella or E. coli O157:H7 isolates. Results from these studies indicate that short-term ionophore feeding had very limited effects on E. coli and Salmonella shedding or on antimicrobial susceptibility in experimentally infected lambs. 相似文献
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复方氟苯尼考口服液对人工诱发鸡大肠杆菌病的疗效试验 总被引：2，自引：0，他引：2
采用 5%复方氟苯尼考口服液对人工诱发的鸡大肠杆菌病进行治疗试验。结果表明 ,5%复方氟苯尼考口服液在剂量为 0 .6 ,0 .3 ,0 .1 5m L/ L给药时 ,能有效的控制鸡大肠杆菌感染 ,缓解症状 ,降低大肠杆菌感染鸡只的发病率和死亡率 ,并在一定程度上减少成活鸡的体重下降 ,效果优于单方的氟苯尼考口服液 ,在临床上有一定的实用价值 ,值得推广使用。临床应用治疗鸡大肠杆菌病推荐剂量为每升水 0 .3 m L。 相似文献
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LI Chen ZHANG Shuang-xiang ZHOU Bi-jun CHENG Zhen-tao WEN Ming MA Guang-qiang WANG Wei HU Xing-yi ZHANG Hai DING Zun-e WANG Kai-gong 《中国畜牧兽医》2017,44(12):3625-3633
In order to find out the serotype, resistant phenotype and genotype of Escherichia coli (E. coli) and Salmonella in piglets, this study collected 128 samples of diarrhea piglets from seven large-scale pig farms in five cities in Guizhou province, and the E. coli and Salmonella were isolated and identified. The pathogenicity of the strain was identified by animal test. The drug resistance of the main pathogen was tested by drug susceptibility paper. The resistance gene of each pathogen was detected by PCR. The drug resistance and genotype correlation of the bacterial were analyzed. The results showed that 78 strains of pathogenic E. coli and 21 strains of Salmonella were isolated and identified in this study. The serotypes of pathogenic E. coli were predominantly O138 and O87. Salmonella Typhimurium and Salmonella Enteritidis were predominant serotypes. The susceptibility test showed that the resistant strains of 78 strains of E. coli were more than 80% resistant to β-lactams and more than 40% for other antibacterials. The resistance rate of 21 strains of Salmonella to aminoglycosides was more than 50% and more than 20% to other types of antibacterials; 12 and 10 kinds of drug resistance-related genes of E. coli and Salmonella were detected, respectively; The coincidence rate of resistant genotype and phenotype of two kinds of bacteria were above 60%, and both were multiple drug resistance. This study provided a theoretical basis for comprehensive prevention and control of piglets diarrhea. 相似文献
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为探明仔猪细菌性腹泻肠道致病性大肠埃希氏菌和沙门氏菌流行的血清型、耐药表型及耐药基因型,本试验采集了贵州省5个地（州）市7个规模化养猪场的128份腹泻仔猪肠道样本,并对采集的样本进行了大肠埃希氏菌和沙门氏菌分离与鉴定,通过动物试验鉴定菌株的致病性,利用血清学方法鉴定其血清型,并通过药敏纸片法对主要致病菌进行耐药性研究,采用PCR技术检测各致病菌株耐药相关基因,分析细菌耐药表型和耐药基因型相关性。结果显示,本研究共分离鉴定到78株致病性大肠埃希氏菌与21株沙门氏菌,致病性大肠埃希氏菌血清型以O138、O87为主,沙门氏菌血清型以鼠伤寒沙门氏菌、肠炎沙门氏菌居多;药敏试验结果表明,本试验分离到的78株致病性大肠埃希氏菌对β-内酰胺类药物耐药率达80%以上,对其他种类的抗菌药耐药率均超过40%,分离鉴定的21株沙门氏菌对氨基糖苷类药物耐药率达50%以上,对其他种类的抗菌药耐药率均达20%以上;本试验分离鉴定的致病性大肠埃希氏菌共检出12种耐药相关基因,沙门氏菌共检出10种耐药相关基因,两种细菌耐药基因型与耐药表型符合率均达60%以上,且均为多重耐药。本研究为仔猪腹泻的综合防控提供了理论依据。 相似文献
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试验研究了添加不同梯度水苏糖对肉鸡鼠伤寒沙门氏菌攻毒的控制效果。试验选用1日龄体重相近(45.52±1.48)g的健康AA肉鸡公雏72只,随机分为3个处理,设6个重复,每个重复4只。在玉米-大豆浓缩蛋白日粮基础上分别添加0、0.4%和0.8%水平的水苏糖。结果表明:日粮添加水苏糖降低了肉鸡体重;肉鸡肠道沙门氏菌控制效果不显著,第19天时,0.4%水苏糖添加组的大肠杆菌数显著高于其他2组(P<0.05),乳酸菌各处理之间差异不显著;pH值与盲肠指数无差异(P>0.05)。以上研究表明,该梯度水苏糖不能控制肉鸡沙门氏菌感染,对肉鸡无保护作用。 相似文献
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柞蚕抗菌肽D基因在酵母中表达的研究 总被引：8，自引：2，他引：6
柞蚕抗菌肽具有广谱杀菌功能，人工合成抗菌肽Ｄ基因（１２２ｂｐ）与含α－因子及前导肽序列的穿梭质粒ｐＣＬＷＡ２重组，克隆于酵母ＡＢ１０３。在缺亮氨酸的ＹＥ培养基中筛选Ｌｅｕ＋阳性的转化子。转化子菌株培养扩增后提取重组质粒与抗菌肽基因片段探针作点杂交为阳性，电泳后插入含抗菌肽Ｄ基因１２８ｂｐ的区带。在转基因酵母的发酵液中分离上清液，浓缩，对抗菌肽敏感的指示菌Ｅ．ｃｏｌｉＫ１２Ｄ３１有明显抑菌效应。证实人工合成柞蚕抗菌肽Ｄ基因在酵母中表达。 相似文献