四川和重庆地区鸭源沙门氏菌分离鉴定及血清型分析

为了解四川和重庆地区规模化种鸭场鸭源沙门氏菌流行情况,本研究从四川和重庆地区规模化种鸭场采集病料样品366份,分离出163株鸭源沙门氏菌。血清型鉴定结果显示163株沙门氏菌中有96株能够确定血清型,分属A、B、C1、C2、D及F共6个血清群;另有67株属于粗糙型菌落未能分型。优势菌株为伊鲁木沙门氏菌、甲型副伤寒沙门氏菌及奥雷宁堡沙门氏菌。其次为习志野沙门氏菌、鼠伤寒沙门氏菌、肠炎沙门氏菌、猪霍乱沙门氏菌、奥斯陆沙门氏菌、姆卡巴沙门氏菌及昌丹斯沙门氏菌。采用已确定血清型的7株鸭源沙门氏菌人工感染实验雏鸭,结果显示7株鸭源沙门氏菌均具有致病性,死亡率为20%~100%,平均死亡率77.14%。本研究为进一步研究鸭源沙门氏菌流行情况和血清型分布情况提供参考。     

粤北地区鸡沙门氏菌分离株的生化反应特性

本研究对粤北地区分离到的不同鸡沙门氏菌属的细菌进行生化特性的研究.结果发现,鸡沙门氏菌属粤北分离株的鸡白痢沙门氏菌、鸡亚利桑那沙门氏菌、鸡伤寒沙门氏菌都有其独特的生化反应特性.利用这些特性很容易将以上几种鸡沙门氏菌进行鉴定,对临床诊断有重要意义.     

针对fimW基因沙门氏菌的特异性PCR检测

为建立沙门氏菌快速检测方法,本研究根据沙门氏菌Ⅰ型菌毛蛋白调控基因fimW设计一对引物,建立PCR检测方法,并对收集的A群～F群14个血清型40株沙门氏菌和5种12株非沙门氏菌菌株进行PCR扩增.结果显示所有沙门氏菌均扩增出与预期(477 bp)相符的特异性片段,而非沙门氏菌扩增结果均为阴性.另外,以肠炎沙门氏菌50336株DNA为模板,敏感性试验结果显示该方法可以检测出扩增体系中1pg DNA染色体和102cfu的沙门氏菌.表明本研究建立了检测沙门氏菌简洁、敏感、特异的PCR方法.     

4株鸽源沙门氏菌致病性观察

为了解分离自四川地区的鸽源沙门氏菌的致病性,本研究先将分离的4株沙门氏菌,腹腔注射SPF昆明鼠,测定其半数致死量(LD50),再依据小鼠攻毒试验结果,选取致病性较强的纽波特沙门氏菌菌株,通过灌胃方式接种信鸽来观察对信鸽的致病性.结果显示:甲型副伤寒沙门氏菌、纽波特沙门氏菌、伯里沙门氏菌、基桑加尼沙门氏菌的LD50分别为3.37×10^6、2.49×10^7、5.46×10^7、3.58×107 CFU;感染鼠的肝脏、脾脏、肾脏及小肠有明显的炎性病变;纽波特沙门氏菌可造成感染鸽的肝脏、肺脏、肾脏和胰腺纤维素样变性及炎性细胞浸润等病变,回肠、空肠、盲肠的肠绒毛结构不完整、绒毛上皮脱落,绒毛及肌层有不同程度的炎性细胞浸润.以上结果表明,4株分离的沙门氏菌对试验鼠有一定的致病性,纽波特沙门氏菌可造成信鸽气囊等组织器官损伤,继而影响其飞行能力.本研究为鸽源沙门氏菌尤其是纽波特沙门氏菌的致病性研究提供一定的理论参考,具有公共卫生学意义.     

鸡沙门氏菌脉冲场凝胶电泳分型研究

为应用脉冲场凝胶电泳(PFGE)从分子水平上对禽源沙门氏菌之间的差别进行分析和研究,本研究采用自动微生物鉴定仪对12株疑似鼠伤寒沙门氏菌和15株疑似鸡白痢沙门氏菌进行了鉴定.以限制性核酸内切酶Xba I对其全基因组DNA进行酶切、PFGE分型,Info Quest FP聚类分析软件对电泳结果进行分析.结果显示,共鉴定出11株鼠伤寒沙门氏菌、1株圣保罗沙门氏菌、6株阿姆斯特丹沙门氏菌、5株亚拉巴马沙门氏菌、1株鸡白痢沙门氏菌、2株纽波特沙门氏菌和2株肠炎沙门氏菌,一共分为12个PFGE型.实验结果表明,江苏地区存在有不常见的沙门氏菌血清型,同种血清型之间的基因型差别较小(相似值为0.85～1),不同血清型之间差别较大(相似值为0.45～0.70).PFGE能从分子水平上对禽源沙门氏菌的基因组DNA进行分型.     

浅谈沙门氏菌威胁家禽笼养方式

家禽养殖业要永远防控沙门氏菌,这绝对不是无缘无故的,因为沙门氏菌是在人体内引起胃肠道疾病的一个重要致病源,在欧洲人体感染的沙门氏菌病中最常被分离出来的是肠炎沙门氏菌(主要来源于家禽)和鼠伤寒沙门氏菌(主要来源于猪)。被沙门氏菌感染的鸡蛋也是人类感染肠炎沙门氏菌的一个重要感染源。1饲养方式的影响许多领域的研究,从小型到大型的,都评估了鸡舍饲养模式在感染沙门氏菌方面的影响。通常,这些研究有各式各样的结果,包括从笼养模式减少了沙门氏菌     

上海市猪源沙门氏菌耐药性及脉冲场凝胶电泳分型研究

为了解上海地区猪源沙门氏菌的耐药性及基因分型情况,本研究对2013年分离到的13株猪源沙门氏菌(10株为猪霍乱沙门氏菌,3株为鼠伤寒沙门氏菌)采用微量肉汤稀释法进行药物敏感性测定,应用脉冲场凝胶电泳(PFGE)进行基因分型。药物敏感试验结果表明,分离到的13株沙门氏菌对磺胺异恶唑、多西环素、氟苯尼考和阿莫西林的耐药率较高,对阿莫西林/棒酸、头孢曲松、丁胺卡那霉素和头孢噻呋敏感。脉冲场凝胶电泳分型结果显示,10株猪霍乱沙门氏菌中有8株为流行病学相关,是本次研究中猪霍乱沙门氏菌的优势基因型。     

沙门氏菌的检测方法

沙门氏菌是一类广泛分布于自然界,肠杆菌科中一种重要的人畜共患、革兰氏阴性病原菌。不仅能导致仔猪副伤寒、流产等多种动物疾病,而且在世界各地的食物中毒中,沙门氏菌引起的食物中毒病例占首位或第二位。沙门氏菌菌型繁多,已确认的沙门氏菌有2500个以上血型。因此,沙门氏菌的检测一直是沙门氏菌研究的核心问题。     

4种鸡源致病性沙门氏菌多重PCR检测方法的建立及应用

建立一种多重PCR方法,同时检测肠炎、鼠伤寒、鸡白痢/鸡伤寒沙门氏菌。针对沙门氏菌属特异性invA基因、肠炎沙门氏菌特异性Sdf I序列、鼠伤寒沙门氏菌特异性STM4497基因、鸡白痢/鸡伤寒沙门氏菌flhB基因设计引物,对引物浓度和反应条件进行优化,并对多重PCR特异性和灵敏度进行评估。利用建立的多重PCR方法调查河北地区蛋种鸡生产链中沙门氏菌流行现状。研究建立的多重PCR方法可快速、特异性鉴别肠炎、鼠伤寒、鸡白痢/鸡伤寒沙门氏菌,最低检出限为100 CFU细菌和0.5 ng基因组DNA。沙门氏菌流行病学调查显示,肠炎沙门氏菌是河北地区蛋种鸡生产链中沙门氏菌主要流行血清型。成功建立鉴别肠炎、鼠伤寒、鸡白痢/鸡伤寒沙门氏菌的多重PCR方法,对沙门氏菌流行病学调查及临床快速诊断具有重要意义。     

鸡源沙门氏菌流行病学调查及耐药性分析

为了了解广东韶关地区鸡源沙门氏菌的流行病学及其耐药性特点,本研究通过对2022年对采集自广东韶关地区41个规模养鸡场和28个土鸡散养场的鸡喉头、泄殖腔拭子,病死鸡的肝脏、心血、脾、肠道内容物共737份样品进行细菌分离培养、病原菌的生化鉴定和药敏试验,研究广东韶关地区鸡源沙门氏菌的流行病学及其耐药性特点。结果显示409份样品分离到沙门氏菌,检出率55.50%,总体泄殖腔沙门氏菌检出率73.89%,咽喉部沙门氏菌检出率35.88%,病死鸡病料沙门氏菌检出率78.38%,规模场沙门氏菌检出率为47.21%,散养场沙门氏菌检出率为65.95%。分离菌株普遍对阿奇霉素、头孢噻肟、阿米卡星、氧氟沙星、诺氟沙星、环丙沙星、恩诺沙星敏感,对青霉素、氨苄西林、链霉素、卡那霉素、四环素、阿莫西林、氟苯尼考、泰乐菌素、林可霉素、克林霉素耐药,多重耐药比高达82.61%。沙门氏菌多重药物耐药的规模场比例为95.12%,散养场比例为64.29%。本研究为广东韶关地区鸡源沙门氏菌病的防控提供了参考。     

减毒沙门氏菌作为口服活疫苗载体的研究进展

文章就沙门氏菌相关基因的特点、减毒沙门氏菌载体激发的免疫应答、进入机体免疫系统的机制、减毒沙门氏菌的应用、载体疫苗的优越性及潜在危险性几方面综述了减毒沙门氏菌作为口服疫苗载体的研究进展,为新型菌苗的研制提供一种新的思路。     

Factors affecting costs for on-farm control of salmonella in Swedish dairy herds

Background

The Swedish control program for salmonella includes restrictions and on-farm control measures when salmonella is detected in a herd. Required control measures are subsidised by the government. This provides an opportunity to study costs for on-farm salmonella control. The aim of this study was to describe the costs for on-farm salmonella control in Swedish cattle herds and to investigate the effects of herd factors on these costs in dairy herds.

Results

During the 15 years studied there had been a total of 124 restriction periods in 118 cattle herds; 89 dairy herds, 28 specialised fattening herds and three suckler herds. The average costs per herd for on-farm salmonella control was 4.60 million SEK with a median of 1.06 million SEK corresponding to approximately 490 000 and 110 000 EUR. The range was 0.01 to 41 million SEK corresponding to 1080 EUR to 4.44 million EUR per farm. The costs cover measures required in herd-specific control plans, generally measures improving herd hygiene. A mixed linear model was used to investigate associations between herd factors and costs for on-farm salmonella control in dairy herds. Herd size and length of the restriction period were both significantly associated with costs for on-farm control of salmonella with larger herds and longer periods of restrictions leading to higher costs. Serotype detected and administrative changes in the Swedish Board of Agriculture aiming at reducing costs were not associated with costs for on-farm salmonella control.

Conclusions

On-farm control of salmonella in Swedish cattle herds incurred high costs but the costs also varied largely between herds. Larger herds and longer restriction periods increased the costs for on-farm control of salmonella in Swedish dairy herds. This causes concern for future costs for the Swedish salmonella control program as herd sizes are increasing.     

植物乳酸杆菌对感染沙门氏菌蛋鸡血浆生化、免疫水平及沙门氏菌定植的影响

本试验旨在研究植物乳酸杆菌对感染肠炎沙门氏菌蛋鸡血浆生化、免疫水平及沙门氏菌定植的影响。将400只京红1号商品代蛋鸡随机分成4个处理组,每组5个重复,每个重复20只鸡。A组和C组饲喂基础饲粮,B组和D组在基础饲粮添加2×10~8 CFU/g植物乳酸杆菌。饲喂1周后,C组和D组连续2 d口服1×10~10CFU/m L肠炎沙门氏菌菌液,A组和B组口服等量无菌PBS溶液,饲养3周。结果表明:添加植物乳酸杆菌可显著提升总蛋白、球蛋白水平(P0.05),显著降低低密度脂蛋白和甘油三酯(P0.05);添加植物乳酸杆菌可显著增加IgM、IgG(P0.05);蛋鸡感染沙门氏菌的第14天和第21天及试验全程,添加植物乳酸杆菌显著减少盲肠食糜中肠炎沙门氏菌拷贝数(P0.05)。综上可知,日粮中添加植物乳酸杆菌可改善感染肠炎沙门氏菌蛋鸡的血浆生化指标,缓解炎症损伤,降低盲肠沙门氏菌定植数量,保障机体健康。     

An assessment of soybeans and other vegetable proteins as source of salmonella contamination in pig production

Background

The impact of salmonella contaminated feed ingredients on the risk for spreading salmonella to pigs was assessed in response to two incidences when salmonella was spread by feed from two feed mills to 78 swine producing herds.

Methods

The assessment was based on results from the salmonella surveillance of feed ingredients before introduction to feed mills and from HACCP - based surveillance of the feed mills. Results from the mills of the Company (A) that produced the salmonella contaminated feed, were by the Chi. Square test compared to the results from all the other (B - E) feed producers registered in Sweden. Isolated serovars were compared to serovars from human cases of salmonellosis.

Results

Salmonella (28 serovars) was frequently isolated from imported consignments of soybean meal (14.6%) and rape seed meal (10.0%). Company A largely imported soybean meal from crushing plants with a history of unknown or frequent salmonella contamination. The risk for consignments of vegetable proteins to be salmonella contaminated was 2.4 times (P < 0.0006) larger for A when compared to the mills of the other companies which largely were supplied by soybean meal from a crushing plant with a low risk for salmonella contamination. Also the level of feed mill contamination of salmonella was higher for feed mills belonging to Company A in comparison to the other companies before and also after heat treatment. Four (10.5%) of the 38 serovars isolated from feed ingredients (28) and feed mills (10) were on the EU 2007 top ten list of human cases of salmonellosis and all but eight (78.9%) on a 12 year list (1997-2008) of cases of human salmonellosis in Sweden.

Conclusions

Salmonella contaminated feed ingredients are an important source for introducing salmonella into the feed and food chain. Effective HACCP-based control and associated corrective actions are required to prevent salmonella contamination of feed. Efforts should be taken to prevent salmonella contamination already at the crushing plants. This is challenge for the EU - feed industry due to the fact that 98% of the use of soybean/meal, an essential feed ingredient, is imported from crushing plants of third countries usually with an unknown salmonella status.     

PCR技术检测饲料中沙门氏菌的应用研究

用聚合酶链反应(PCR)技术检测饲料中沙门氏菌,对已知被沙门氏菌污染的动物饲料培养物均能检出阳性,说明本方法对检测饲料中沙门氏菌具有特异性高、灵敏、快速等特点,适用于快速、准确地检测饲料中沙门氏菌的需要。     

Failure of drinking water sanitisation to reduce the incidence of natural salmonella in broiler chickens

The addition of a sanitiser, containing a mixture of organic acids and other approved additives, to water offered to broiler chickens was effective in eliminating salmonella from the drinking water. However, it failed to influence salmonella carriage by the chickens which were still shedding salmonella at market age (seven weeks old).     

Differences and similarities among experts' opinions on Salmonella enterica dynamics in swine pre-harvest

A workshop was conducted to elicit expert opinion on infection status and transmission of salmonella in pigs at the farm of origin, during transport and during lairage. A second objective was to compare opinions regarding risk factors for salmonella introduction and control at the farm level between experts from different countries. Thirty-six experts from 11 countries filled in a paper-and-pencil questionnaire during an international conference. Experts from all countries agreed on the risk of salmonella introduction related to live animals and the importance of general hygiene and all-in/all-out management for salmonella control. However, workshop participants from Denmark put more weight on factors related to feed while experts from USA rated factors related to rodents and people contact higher. The experts believed that 21-33% of pigs coming from a chronically infected farm would be infected with salmonella, but only one-third of the infected pigs would be shedders. Regarding transport and lairage, the US participants believed that contamination was occurring in the majority of pigs regardless of initial infection status and particularly during lairage; in contrast, the Danish experts were more optimistic with respect to the contamination and infection risk. US experts believed that the incidence of salmonella shedding would be high among pigs infected during transport and lairage and that an important proportion of 'carrier' pigs would start shedding.Our results reflect the differences in the level of salmonella infection and implemented control strategies between countries as well as the different philosophies that professionals have. The differences in opinion regarding salmonella dynamics could be due either to true differences in risk as a consequence of distinct management and transport practices in Denmark and USA or to a difference in perception.     

Comparative studies on enrichment and selective media for isolation of Salmonellae from faecal specimens.

Enrichment media (tetrathionate, selenite and Rapp ap ort broths) and selective media (desoxycholate citrate agar and brilliant green agar) were tested in different combinations to ascertain their capacity for isolation of salmonella bacteria. The material consisted of 299 samples of cattle faeces from two herds infected with salmonella (Table 1), and of 111 artificially contaminated samples of pig faeces (Table 3). The tetrathionate and selenite broths were equally useful for the material as a whole, whereas the results varied between different species of salmonella which is of great practical interest. The number of salmonella isolations was much lower when enrichment with Rappaport broth was used. The rate of salmonella isolations can often be increased by parallel enrichments with two different media. Of the selective agar media tested, brilliant green agar was superior to desoxycholate citrate agar.     

Geographical distribution of salmonella infected pig,cattle and sheep herds in Sweden 1993-2010

Background

The Swedish salmonella control programme covers the entire production chain, from feed to food. All salmonella serotypes are notifiable. On average, less than 20 cases of salmonella in food-producing animals are reported every year. In some situations, the cases would be expected to cluster geographically. The aim of this study was to illustrate the geographic distribution of the salmonella cases detected in pigs, cattle and sheep.

Methods

Data on all herds with pigs, cattle and sheep found to be infected with salmonella during the time period from 1993 to 2010 were obtained from the Swedish Board of Agriculture. Using the ArcGIS software, various maps were produced of infected herds, stratified on animal species as well as salmonella serotype. Based on ocular inspection of all maps, some were collapsed and some used separately. Data were also examined for temporal trends.

Results

No geographical clustering was observed for ovine or porcine cases. Cattle herds infected with Salmonella Dublin were mainly located in the southeast region and cattle herds infected with Salmonella Typhimurium in the most southern part of the country. Some seasonal variation was seen in cattle, but available data was not sufficient for further analyses.

Conclusions

Analyses of data on salmonella infected herds revealed some spatial and temporal patterns for salmonella in cattle. However, despite using 18 years'' of data, the number of infected herds was too low for any useful statistical analyses.     

Salmonella serotypes from animals in New York State, 1978-1983

The salmonella serotypes isolated during 1978 to 1983 at the diagnostic and clinical laboratories of the New York State College of Veterinary Medicine from animal sources in New York state were reviewed and compared to earlier data from New York state animals and to national data for both human and animal sources. A total of 255 salmonella strains were studied from the six year period and included 33 serotypes. Salmonella enteritidis ser Typhimurium continued to be the most commonly reported serotype followed by serotype Anatum. Generally serotypes from New York state animals reflected national data on salmonella serotypes with a few exceptions. Serotype Dublin continued to be absent from New York animal populations. Bovine and equine species were the most common salmonella sources.