Salmonella enterica infections in Spanish swine fattening units

The present study is the first conducted in Spain to estimate the bacteriological herd prevalence of Salmonella enterica in fattening units and to describe the Salmonella serovar diversity on these farms using a sample representative of the entire swine population. For this purpose, 10 faecal samples were collected from 10 different pens containing pigs close to market weight in a total of 232 fattening units. Total sample size was proportionally distributed according to the fattener census in each of the regions of the country and all the samples were examined by culture of 25 g of faecal material. One hundred (43.1%) farms had at least one Salmonella-positive sample (95% CI: 37-49.1%). Salmonella enterica was detected in 290 (12.5%) pooled faecal floor samples (95% CI: 11.2-13.8%). The apparent herd prevalence of salmonellosis was similar among multi-site, finishing and farrow to finish farms. Overall, 24 different serovars were identified, with S. Typhimurium, S. Rissen and S. Derby being the most common both at herd and sample level. Results of phage typing were available for the 91 isolates of S. Typhimurium. A total number of 10 different phage types were identified, with DT 193 being the most frequent. Phage types DT 104, DT 104b and DT U302, which have been associated with several multi-resistant patterns, accounted for 23% and 29% of the Typhimurium total isolates or Typhimurium infected farms respectively.     

用NBT还原法检测细菌无细胞溶解物中SOD活性

目的：了解不同细菌无细胞溶解物中ＳＯＤ活性。方法：采用ＮＢＴ还原法检测２株大肠杆菌和８株沙门氏菌（其中７株伤寒沙门氏菌、１株鼠伤寒沙门氏菌）无细胞溶解物中ＳＯＤ活性。结果：２株大肠杆菌ＳＯＤ活性明显低于８株沙门氏菌（Ｐ＜０．０１）;鼠伤寒沙门氏菌ＳＯＤ活性明显高于伤寒沙门氏菌（Ｐ＜０．０１）;而伤寒沙门氏菌Ｌ型返祖株ＳＯＤ活性低于其它株伤寒沙门氏菌（Ｐ＜０．０１）。结论：不同细菌的ＳＯＤ活性有差异;伤寒沙门氏菌Ｌ型返祖株细胞壁的缺陷可能是导致其ＳＯＤ活性降低的原因之一     

自由市场鲜鸡蛋黄中沙门氏菌的检测

从山东省潍坊市奎文区早春园自由市场随机购买鲜鸡蛋30枚作为检样,蛋黄进行沙门氏菌的检测,通过预增菌、增菌、分离培养及鉴定,发现所购买的这些鸡蛋黄中沙门氏菌检出阳性率为76.7%。     

3种姜科植物提取物的体外抗菌活性

采用试管倍比稀释法研究3种姜科植物(砂仁、草豆蔻和高良姜)乙醇提取物对5种鸡、猪致病菌的体外抗菌活性。结果表明,3种姜科植物提取物对5种致病菌均有较好的抑制作用,对鸡和猪大肠杆菌、鸡和猪金黄色葡萄球菌、鸡沙门氏菌最低杀菌浓度(MBC)分别为125、15.6、62.5 mg/m L。说明3种姜科植物乙醇提取物对鸡、猪5种常见致病菌均具有较好的体外抗菌效果,其中对金黄色葡萄球菌的体外抑杀效果优于大肠杆菌和沙门氏菌。     

产雌马酚梭菌C1对小鸡沙门氏菌攻毒保护效果

部分梭菌对机体的免疫系统具有明显的调节作用,可开发成新型益生菌。由于鸡盲肠内容物中梭菌含量较高,从小鸡肓肠内容物中分离培养功能性梭状芽孢杆菌,并在小鸡中初步研究其对沙门氏菌攻毒的保护效果。该研究首先采用梭菌选择性培养基,从小鸡肓肠内容物中分离获得了一株可以将大豆素转化为雌马酚的革兰氏阳性纤维状梭菌C1,以四环素为对照,研究梭菌C1对小鸡沙门氏菌攻毒的保护作用。结果表明,梭菌C1组和四环素组均具有降低肓肠内容物中沙门氏菌活菌数和促进小鸡生长的功能,推测梭菌C1具有开发为四环素替代品的潜能。虽然较高浓度的S 雌马酚（5 mg·mL-1）在体外对沙门氏菌有一定的抑制作用,梭菌C1也具有将大豆素转化为雌马酚的能力,但梭菌C1在体外对沙门氏菌的抑制作用并不明显,其益生机制还有待进一步研究。     

散养鸡鼠伤寒沙门氏菌的分离?鉴定?耐药性研究

从疑似感染的成年散养鸡蛋壳和发病雏鸡的肝脏、脾脏中分离到2株细菌,通过培养特性、镜检结果、生化鉴定、血清学分型等,2株分离细菌均被鉴定为鼠伤寒沙门氏菌,分别命名为AH-DY01和AH-DY02。药物敏感性检测结果表明,AH-DY01对氟苯尼考、左氧氟沙星和环丙沙星敏感,对其他12种抗生素耐药;AH-DY02对阿米卡星、氟苯尼考、左氧氟沙星、复方新诺明、庆大霉素、链霉素、环丙沙星和大观霉素敏感,对其他7种药物耐药,2株沙门氏菌均表现多重耐药性。动物回归试验结果表明,2株鼠伤寒沙门氏菌均可致死雏鸡。对分离菌的16S r DNA进行测序与遗传进化分析,结果表明AH-DY01与标准菌株ATCC-1592和ATCC13311的同源性最高,而AH-DY02与日本分离株之间的亲缘关系最近。     

冰鲜鸡生产链中沙门氏菌的分离鉴定及PFGE分型研究

为揭示冰鲜鸡生产链中沙门氏菌的分布及传播机制,本研究于2013年7月～2013年12月采集广东某大型一体化养鸡企业下属2个种鸡场、2个孵化场、2个肉鸡场、1个屠宰场和5个销售点样品,用常规法和PCR进行沙门氏菌的分离鉴定,并对分离出的沙门氏菌进行血清学鉴定和PFGE分子分型.种鸡场、肉鸡场、屠宰场和销售点的沙门氏菌的检出率分别为1.46%(7/480)、7.00%(21/300)、62.86%(22/35)和54.67%(41/75),孵化场雏鸡胎粪检出率为1.11%(2/180),死胚检出率为12.00%(9/75).屠宰和销售环节是沙门氏菌污染的重要环节,食品安全风险较高.102株沙门氏菌共产生24种不同的PFGE谱型,从不同环节分离到多组相似度为100%的沙门氏菌,表明冰鲜鸡生产链中存在沙门氏菌沿生产链传播的现象.     

PCR技术检测饲料中沙门氏菌的应用研究

用聚合酶链式反应穴PCR雪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的培养物均能检出阳性,说明PCR方法对检测饲料中沙门氏菌具有特异性高,且灵敏、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。     

Detection of Salmonella in Finishing Pigs on Farm and at Slaughter in Piedmont,Italy

Salmonella is one of the most common causes of human gastroenteritis often associated with pork consumption. The aims of this cross‐sectional study were to collect preliminary data on the presence of Salmonella enterica in pigs in Piedmont (Italy), through sampling on farm and at slaughter and to gather pilot data on serotypes and phagetypes present in the sampled area and distribution of anti‐microbial resistance among isolated strains. Salmonella was detected through culture and identified with Salmonella spp. and Salmonella Typhimurium PCR; positive samples were serotyped, phagetyped and tested for antibiotic susceptibility. Positive samples (from 9% of faeces up to 29% of tonsils) were found in 64% of the herds. Salmonella spp. was retrieved also from scalding water. Most of the isolates were Salmonella Derby, Salmonella Typhimurium and Salmonella 4,5,12:i:‐. The results of Salmonella Typhimurium specific PCR suggested that Salmonella 4,5,12:i:‐ might be unrecognized by serotyping. Anti‐microbial resistance was recorded in 75–100% of the isolates. Phagetyping allowed the identification of DT104B and DT46A strains. These results set the bases for further research studies that would aim to estimate the real herd prevalence in Piedmont and the diffusion of serotypes and anti‐microbial resistant strains within the same region.     

Effects of dietary additives (potassium diformate/organic acids) as well as influences of grinding intensity (coarse/fine) of diets for weaned piglets experimentally infected with Salmonella Derby or Escherichia coli

The aim of this study was to examine whether and to what extent the addition of potassium diformate (pdf) or free organic acids (fpa) to the diet and the grinding intensity might affect the course of infection and the passage of orally applied Salmonella and Escherichia coli in pigs. Experiments were carried out using 80 reared piglets allotted to four groups. Pigs were fed pelleted diets ad libitum (except during a 15 h feed‐withholding‐period before infection). The control diet contained finely ground cereals (2 mm screen). To two test diets (also finely ground) 1.2% pdf, 0.9% organic acids (75% formic and 25% propionic acid, fpa) respectively were added. The fourth diet (without acids) was based on coarsely ground cereals (6‐mm screen). After experimental infection alternately with S. Derby or E. coli, the course of infection was examined (rectal swab technique). Pigs were sacrificed 4–5 h after a further oral application of ～10⁹–10¹⁰ CFU S. Derby or E. coli to determine the counts of Salmonella or E. coli in chyme (classical culture methods). Adding pdf or fpa to the diet led to reduced Salmonella shedding and resulted in significantly lower counts of Salmonella and E. coli in the stomach content indicating an improved efficacy of the stomach barrier. In the distal parts of the digestive tract, the effect was less obvious concerning counts of E. coli, whereas counts of Salmonella were reduced markedly as well. The diet based on coarsely ground cereals failed to demonstrate positive effects concerning infection and passage of orally applied bacteria as well, but this diet was also pelleted and showed unintentionally, comparable amounts of fine particles. Results obtained in this study allow the recommendation of using pdf or organic acids as additives when dietary measures against Salmonella or E. coli in pigs are required.