不同方法检测鸡白痢沙门氏菌抗体消长规律的比较研究

为比较不同方法检测鸡白痢沙门氏菌抗体消长的规律,以便为种鸡场净化提供科学指导,本研究以鸡白痢沙门氏菌活菌和灭活免疫原分别接种SPF鸡,采用平板凝集、微量凝集和ELISA试验定期检测血清中的特异性抗体,并以Kappa检验判定不同检测方法之间的一致性程度。结果显示,平板凝集试验在接种后检出抗体阳转的时间早于ELISA,但ELISA检出抗体阳性的持续时间更长,且更符合抗体消长规律;3种检测方法的结果之间仅具有微弱一致性(Kappa系数为0.002~0.295)。本研究结果表明,不同鸡白痢沙门氏菌抗体检测方法之间存在较大差异,但从总体来看,ELISA无假阳性干扰,检出抗体的持续时间较长,更符合抗体消长规律,在单一鸡白痢沙门氏菌感染的情况下,更有利于种鸡场对该病进行净化。     

不同方法检测鸡白痢沙门氏菌抗体消长规律的比较研究

为比较不同方法检测鸡白痢沙门氏菌抗体消长的规律，以便为种鸡场净化提供科学指导，本研究以鸡白痢沙门氏菌活菌和灭活免疫原分别接种SPF鸡，采用平板凝集、微量凝集和ELISA试验定期检测血清中的特异性抗体，并以Kappa检验判定不同检测方法之间的一致性程度。结果显示，平板凝集试验在接种后检出抗体阳转的时间早于ELISA，但ELISA检出抗体阳性的持续时间更长，且更符合抗体消长规律；3种检测方法的结果之间仅具有微弱一致性（Kappa系数为0.002~0.295）。本研究结果表明，不同鸡白痢沙门氏菌抗体检测方法之间存在较大差异，但从总体来看，ELISA无假阳性干扰，检出抗体的持续时间较长，更符合抗体消长规律，在单一鸡白痢沙门氏菌感染的情况下，更有利于种鸡场对该病进行净化。     

惠州地区鸡白痢和鸡伤寒沙门菌病血清学调查

为了解惠州地区鸡白痢和鸡伤寒沙门菌病的发生与流行现状,为本病的防治提供依据,采用平板凝集试验对惠州地区的部分禽群进行鸡白痢和鸡伤寒沙门菌病血清学调查。结果显示,惠州地区鸡白痢和鸡伤寒沙门菌病抗体阳性率为8.30%,惠州地区不同养殖模式鸡群、不同县(区)(仲恺区除外)鸡群、不同日龄鸡群、不同用途鸡群,种禽场不同性别禽群均有不同程度感染鸡白痢和鸡伤寒沙门菌病,说明惠州地区的鸡群受鸡白痢和鸡伤寒沙门菌病感染的情况普遍存在,相关部门应该切实加强对该病的防制与净化工作。     

基于鸡白痢沙门菌LPS的D群沙门菌抗体间接ELISA检测方法的建立

通过热酚水法提取并纯化鸡白痢沙门菌的脂多糖(lipopolysaccharide, LPS),以LPS作为包被抗原,建立D群沙门菌抗体间接ELISA检测方法。结果显示,通过方阵滴定法等确定抗原包被质量浓度为2.233 mg/L;血清最佳稀释度为1∶200,最佳作用时间为60 min;最适封闭条件为5%脱脂乳封闭60 min;酶标二抗最适工作质量浓度为1∶8 000,作用60 min;底物显色时间为15 min;阴阳性判定标准为S/P值≥0.5。特异性、敏感性和重复性验证表明,该方法可特异性检测鸡白痢沙门菌等D群沙门菌的阳性血清,与鼠伤寒沙门菌、大肠杆菌等家禽病原菌的阳性血清无交叉反应,其检测灵敏度是鸡白痢平板凝集的400倍,批间重复和批内重复变异系数均小于10%。对临床血清的检测结果表明,该方法与Biochek公司的D群抗体检测试剂盒的阳性符合率为94.67%,阴性符合率为98.11%,总符合率为98.59%。结果表明,该检测方法可用于临床鸡白痢沙门菌等D群沙门菌感染的抗体检测。     

不同厂家鸡白痢抗原检测效果比较

通过血清或全血平板凝集方法淘汰阳性鸡,是目前鸡白痢净化使用的主要检测方法。本研究采用3个不同厂家鸡白痢抗原分别检测人工感染SPF鸡制备的试验血清和对照血清,比较不同抗原的敏感性和稳定性。结果显示,3种抗原对试验组血清样品的总检出率抗原BAC,不同抗原之间阳性符合率较低。3种抗原稳定性均较差,同批次阳性符合率均低于85%,抗原A和B批次间阳性符合率低于60%。本研究将为鸡白痢凝集抗原的选择提供参考依据。     

伊犁河谷地区父母代种鸡场REV与鸡白痢流行病学调查

为掌握伊犁河谷地区不同来源黄羽父母代肉种鸡网状内皮组织增生病病毒(REV)与鸡白痢流行情况,为父母代肉种鸡场引种提供重要依据.本研究通过酶联免疫吸附实验(ELISA)方法和鸡白痢伤寒沙门氏菌血清平板凝集实验,从6家种鸡场采集5个不同来源的父母代肉种鸡种公鸡血样879份,进行REV血清抗体检测及鸡白痢检测.结果:不同来源...     

抗沙门菌PEG菌毛单克隆抗体的制备及初步临床应用

为制备抗沙门菌PEG菌毛单克隆抗体(MAb),本研究从鸡白痢沙门菌(CVCC526)基因组中扩增菌毛蛋白基因peg A,将其克隆至原核表达载体pET-22b(+)中构建重组质粒pET-peg A,转化至大肠杆菌BL21(DE3)感受态细胞中,经IPTG诱导表达并纯化重组蛋白rPegA。应用该蛋白免疫BALB/c小鼠,取其脾细胞与SP2/0细胞融合,经间接ELISA筛选后获得1株稳定分泌MAb的杂交瘤细胞株,命名为3D12,抗体亚类鉴定其属于IgG1亚类,腹水效价为1∶64 000。通过western blot和玻板凝集试验检测结果显示,该MAb与肠炎沙门菌、鸡白痢沙门菌和鸡伤寒沙门菌呈阳性反应,而与鼠伤寒沙门菌、大肠杆菌CE2、CE7、CE53、DH5α均不发生反应。以PEG菌毛MAb建立玻板凝集方法,检测本实验室临床分离保存的72份禽源沙门菌,同时以商品化沙门菌诊断血清作为平行对照,结果两种方法符合率达97.2%。本研究研制的MAb可用于沙门菌PEG菌毛基础研究和快速检测。     

竹丝鸡和PSF鸡人工感染鸡白痢沙门菌的抗体消长规律

本研究通过人工感染鸡白痢沙门菌到竹丝鸡和SPF鸡,采用血清平板凝集的方法检测鸡白痢抗体,用于确定鸡白痢抗体的消长规律。结果表明:不同品种间鸡性成熟时间具有差异,鸡白痢抗体高峰出现时间也不完全相同。在不同感染方式下鸡白痢抗体消长规律具有差异,腹腔注射组抗体产生最快,滴鼻组次之,同居感染组抗体产生最慢。     

对禽伤寒和鸡白痢两个老病的新认识

禽伤寒和鸡白痢分别是由鸡伤寒和鸡白痢沙门菌引起的禽类的两种不同的败血性传染病。一个多世纪以来,科学家们一直努力在家禽养殖业中控制这两种疾病,但是防控效果不佳或气候条件适于鸡伤寒和鸡白痢沙门菌传播的国家,禽伤寒和鸡白痢仍然是养殖业面临的一个严重问题。过去的15~20年出现了大量有关这两种沙门菌的遗传和免疫学信息,使得人们能更好地了解这两种沙门菌及其与宿主的互作。然而,在了解这两种沙门菌病理学等基础知识的同时,还需要有创造性的思维,以解决当前存在的问题,并研发出控制禽伤寒和鸡白痢沙门菌感染的新方法。     

鸡白痢沙门氏菌的净化效果监测

正沙门氏菌病是一种多种动物共患的传染病,其病原是沙门氏杆菌。根据病原特点,它可以分为三种不同的疾病,即禽伤寒、地方流行性禽副伤寒和鸡白痢。近年来,鸡白痢沙门氏菌流行广泛,给养禽业造成了严重的影响和较大的经济损失。为了解新疆维吾尔自治区规模化肉种鸡场鸡白痢沙门氏菌的感染情况,分6批从4栋鸡舍采集血清2400份,进行鸡白痢沙门氏菌抗体检测,并对鸡场采取了净化措施。     

Salmonella enteritidis and other Salmonella in laying hens and eggs from flocks with Salmonella in their environment.

Seven Canadian layer flocks with Salmonella enteritidis in their environment were investigated to determine the numbers of hens infected with S. enteritidis, the localization of S. enteritidis in organs of infected hens and the numbers of S. enteritidis-infected eggs produced by two affected flocks. By a microagglutination test (MAT) using S. pullorum antigens, these flocks had more seropositive hens (mean 51.9 +/- 16.9%) than two Salmonella-free flocks (mean 13.0 +/- 4.2%). Culture of tissues of 580 hens (433 seropositive) from the seven flocks detected 26 (4.5%) S. enteritidis-infected hens from two flocks. In one flock, 2/150 hens were infected with S. enteritidis phage type (PT) 8, which was confined to the ceca, and no Salmonella spp. were isolated from 2520 eggs (one day's lay). In the second flock, where 24/150 hens were infected with S. enteritidis PT13, extraintestinal infection was found in nine hens and involved the ovaries and/or oviduct in two hens. Salmonella enteritidis PT13 was isolated from one sample of egg contents and from one sample of cracked shells from among 14,040 eggs (one day's lay) from this flock. The overall prevalence of S. enteritidis-contaminated eggs from the two flocks with infected hens was less than 0.06%. Other Salmonella spp. isolated were S. heidelberg from 58 hens (10%), and S. hadar, S. mbandaka and S. typhimurium from one hen (0.2%) each. The MAT with antigens of S. pullorum had a sensitivity of 81% and a specificity of 24% for detecting S. enteritidis-infected hens.(ABSTRACT TRUNCATED AT 250 WORDS)     

Prevalence of Salmonella and multiple antimicrobial-resistant Salmonella in California dairies

A cross-sectional survey was conducted on 75 randomly selected dairies in one California county. Salmonella was isolated from 12 (16%) dairies; S newport was isolated from 6 (8%). Chloramphenicol-resistant S newport and S dublin were isolated from 8 (10.7%) dairies. Dairies with Salmonella had higher average calf mortality rates (P = 0.064; odds ratio [OR], 3.8). Dairies with S newport had a greater than expected occurrence of illnesses in adult cows compared with dairies with no S newport (P = 0.048; OR, 6.7) or with no Salmonella serotypes isolated (P = 0.047; OR, 6.9). Dairies with chloramphenicol-resistant Salmonella were more likely to have used chloramphenicol during the preceding 18-month period compared with dairies with chloramphenicol-susceptible Salmonella or no Salmonella (P = 0.023; OR, 9.5).     

Salmonella enteritidis clearance and immune responses in chickens following Salmonella vaccination and challenge

Our previous work showed that the cell-mediated immunity (CMI) was enhanced by live Salmonella vaccine (LV). The objective of this study was to evaluate the impact of live and killed Salmonella vaccines on Salmonella enteritidis (SE) clearance and to determine if the clearance was mediated by cell-mediated and/or humoral immunity. Chickens were first immunized at 2 weeks of age followed by a booster dose at 4 weeks, challenged with live SE 2 weeks later (6-week-old) and tested for CMI, antibody response and SE clearance 1-week post SE-challenge (7-week-old). Spleen cell proliferation induced by SE-flagella and Concanavalin A (Con A) were significantly higher and SE shedding was significantly lower in the LV group. The splenic CD3 population was significantly lower and B cells were higher in the control group compared to all the SE-challenged groups (with and without vaccination). Serum antibody to SE-flagella and envelope were significantly higher in the KV group compared to all the other groups. These results suggest that LV protects against SE infection, probably by enhancing the CMI.     

Comparison of the environmental survival characteristics of Salmonella Dublin and Salmonella Typhimurium

To examine possible correlations in bovine Salmonella isolates between environmental survival and serovar-associated epidemiological patterns, bovine field isolates of Salmonella serovars Typhimurium and Dublin (two each) were inoculated into bovine faeces slurry and tested monthly by culture for survival during a six-month period of storage at a variable ambient temperature in a disused animal transporter. Low moisture conditions, where the slurry was dried onto wooden dowels, increased detectable survival of a low-level inoculum by up to five months, compared with wet slurry. A more modest increase of survival time was seen with storage of wet slurry under refrigeration at 4°C. Under both dry and wet conditions, the concentration of culturable Salmonella Typhimurium declined at a slower rate than did that of Salmonella Dublin. Salmonella that was naturally contaminating bovine faeces from farms with Salmonella Typhimurium did not show superior survival times compared with Salmonella Typhimurium that had been artificially inoculated into samples. The differing survival characteristics of the two serovars that was observed in environmental faeces may complement their different modes of infection in cattle. Salmonella Dublin, being a bovine host-adapted strain that establishes chronic infection in some animals, may have less need to survive for a prolonged period outside of its host than does Salmonella Typhimurium.     

Salmonella Infantis and Salmonella Enteritidis specific bacteriophages isolated form poultry faeces as a complementary tool for cleaning and disinfection against Salmonella

Salmonellosis represents an important public health concern. Several authors point out the inefficiency of the cleaning and disinfection protocols to remove the bacteria from the field. For this reason, innovative techniques, as bacteriophages, could be implemented to control the bacteria. The main objectives of this study were to assess the effect of bacteriophages against Salmonella Infantis and Salmonella Enteritidis on farm surfaces, and to evaluate bacteriophage procedure application as sanitiser against Salmonella in field conditions. Thus, most prevalent serovars in poultry production were selected (Salmonella Infantis and Salmonella Enteritidis) to contaminate farm facilities. Then, two specific bacteriophages isolated from poultry faeces were applied against them. Results showed Salmonella Infantis and Salmonella Enteritidis decreased of 4.55 log₁₀CFU/mL and 3.85 log₁₀CFU/mL, respectively; the maximum reduction in Salmonella was the 5^th day, after 10⁸ PFU/mL and 10³ PFU/mL bacteriophage application. These results highlight bacteriophages as a promising tool together with cleaning and disinfection.     

Salmonella Incidence in Broilers from Breeders Vaccinated with Live and Killed Salmonella

Salmonella reduction in broilers from commercial broiler breeders vaccinated with live and killed Salmonella vaccines was evaluated. Broiler breeders were vaccinated with Poulvac ST live Salmonella Typhimurium vaccine at 1 d of age, and this was repeated at 2 and 6 wk of age. The breeders were then administered a killed autogenous oil emulsion adjuvanted vaccine containing Salmonella Kentucky, Salmonella Heidelberg, and Salmonella Hadar, at 10 and 18 wk of age. From the ages of 36 to 52 wk, eggs from the breeder flock were hatched, and progeny were challenged in 4 separate experiments at 1 d of age by oral gavage with 1 × 10⁶ cfu/chick by either Salmonella Kentucky, Salmonella Heidelberg, Salmonella Hadar, or Salmonella Enteritidis, each containing resistance to naladixic acid at 32 μg/mL. At 17 to 21 d of age, the broilers were euthanized, and 1 side of the cecum was cultured for Salmonella, and the other side of the cecum was used for enumeration on positive samples. Recovered Salmonella was confirmed to be the challenge strain by O-antisera grouping. This study indicated a difference in Salmonella incidence and enumeration between the vaccinated and nonvaccinated breeder groups for certain species. When challenged with serotypes Salmonella Kentucky, Salmonella Hadar, and Salmonella Heidelberg, protection was noted with a reduction of 28, 17, and 11%, respectively, when compared with the control groups. However, protection was not seen when challenged with S. enteritidis. Under the conditions of this study, live and killed vaccination of commercial broiler breeders with Salmonella contributes protection to progeny when challenged at 1 d of age.     

Enrichment for isolating Salmonella Choleraesuis and other Salmonella spp. from pigs

The growth of Salmonella Choleraesuis was examined in Rappaport Vassiliadis broth (RV) and Hajna-tetrathionate broth (HTT) at 37 and 42 degrees C. As the enrichment in RV at 37 degrees C was satisfactory for isolating S. Choleraesuis, we used this enrichment for isolation from the samples collected from 15 asymptomatic pigs reared on a S. Choleraesuis contaminated farm. S. Choleraesuis was frequently isolated from six pigs (40.0%) under field conditions. The isolation of other Salmonella serovars than S. Choleraesuis was attempted by using both RV enrichment at 37 degrees C and HTT enrichment at 42 degrees C. Salmonella organisms were isolated from 156 (44.8%) of 348 fecal samples and more frequently with HTT at 42 degrees C (43.4%) than with RV at 37 degrees C (20.9%). If other serovars in addition to S. Choleraesuis are to be surveyed, HTT enrichment should be used in combination with RV enrichment.