Serologic study of Pasteurella aerogenes sp n.

The antigenic attributes of Pasteurella aerogenes sp n were serologically compared with species of the genera Actinobacillus and Pasteurella. Examination included the tube-agglutination and double-immunodiffusion techniques. The results indicated the possibility of serologically different strains of P aerogenes. Antisera prepared from strains of P aerogenes also reacted well with antigens prepared from Yersinia pseudotuberculosis (P pseudotuberculosis) and P pneumotropica.     

Abortion of a sow caused by Pasteurella aerogenes.

Three strains of the Pasteurella aerogenes complex were isolated as sole pathogens from aborted fetuses of a sow aborted at the 12th week of gestation on a farm of 600 sows. Gross pathology showed no characteristic lesions. The isolates were biochemically identical and resembled P. pneumotropica on the basis of their strong indole and urease positivity but they produced gas, were ornithine decarboxylase negative and fermented mannitol but not trehalose. Only a few differences were apparent in biochemical characteristics between the isolated strains and P. aerogenes. They differed from the type strain of P. aerogenes in ornithine decarboxylase activity, indole production and lactose and mannitol fermentation; however, such strains do occur within this heterogeneous species. At the time of abortion the antibody titre of the aborted sow was 1 in 16 when examined with live bacterial suspension and 1 in 128 if boiled antigen was used. Similar strains could not be isolated from the vaginas of aborted sows or pregnant and newly farrowed sows in the same group. The bacteriological, serological and histological findings support the opinion of other workers on the occasional pathogenic nature of P. aerogenes.     

我国猪群中多杀性巴氏杆菌的基因型分析

本研究旨在了解我国猪群中流行的多杀性巴氏杆菌(Pm)的主要基因型。利用荚膜基因分型、脂多糖(LPS)基因分型、多位点序列分型(MLST)对2013年12月—2017年12月4年间来源于我国各地区规模化猪场患有疑似呼吸系统疾病的病死猪肺、鼻拭子、气管、肝等样品中分离鉴定的Pm进行基因型分析,并对23种主要毒力基因进行检测。结果表明,当前在我国猪群中流行的Pm的荚膜基因型为A(48.85%)、D(42.75%)、F(2.67%),优势基因型为A和D;LPS基因型为L3(25.00%)和L6(75.00%)型,优势基因型为L6;MLST基因型为ST3(21.25%)、ST10(27.50%)、ST11(42.50%)、ST12(2.50%)、ST16(2.50%)、ST74(1.25%)及ST75(2.50%),优势基因型为ST3、ST10和ST11。如果将荚膜基因型、LPS基因型和MLST基因型组合起来看,当前在我国猪群中流行的Pm的主要基因型为荚膜:脂多糖:MLST基因型A:L3:ST3(20.00%)、A:L6:ST10(26.25%)及D:L6:ST11(42.50%)。毒力基因检测的结果发现部分毒力基因的分布表现出一定的"基因型偏好性"。结果提示,D:L6:ST11是我国猪群中流行的多杀性巴氏杆菌的主要基因型,可能与我国猪群中由多杀性巴氏杆菌导致的呼吸道疾病密切相关。     

猪源D型产毒素多杀性巴氏杆菌toxA基因的克隆与表达

皮肤坏死毒素（Dermonecrotic toxin，DNT）是产毒素多杀性巴氏杆菌（Toxigenic Pasteurella multocida，T^＋Pm）的主要毒力因子和保护性抗原。以猪源D型T^＋Pm的基因组DNA为模板，用PCR方法扩增得到了编码DNT的toxA全基因编码序列，共4019bp。将其克隆到pMD18-T载体并测序，结果表明，toxA基因序列与GenBank已报道的5个toxA基因序列的同源性达99．8％以上。将该基因亚克隆到原核表达载体pGEX-KG的GST基因下游，转化BL21（DE3）大肠杆菌，经IPTG诱导表达，获得大小约173000的融合蛋白。Western blot结果表明，该融合蛋白具有良好的反应原性。动物试验表明，该重组蛋白可以诱导小鼠产生高水平的抗体，并可抵抗致死剂量的天然DNT毒素攻击。     

猪多杀性巴氏杆菌的分离鉴定及oppA基因遗传进化分析

【目的】了解福建省猪场猪多杀性巴氏杆菌（Pasteurella multocida,Pm）的流行及oppA基因遗传进化情况。【方法】本研究采用细菌分离培养、生化试验、16S rRNA PCR扩增测序、PCR荚膜分型、oppA基因克隆及相似性分析、动物回归试验等方法对分离菌株进行鉴定和分析。【结果】本研究共分离到10株菌,分离菌在血平板上形成淡灰白色、湿润光滑、奶油露珠状菌落;分离菌株能酵解蔗糖、果糖、麦芽糖和甘露醇,不能分解葡萄糖、枸橼酸盐、乳糖、硫化氢等,与多杀性巴氏杆菌生化特性基本一致;分离菌株16S rRNA序列与GenBank中登录的多杀性巴氏杆菌相似性达99.9%以上,10株分离菌均为多杀性巴氏杆菌;PCR荚膜分型显示,6株分离菌为荚膜A型,4株为荚膜D型;基于oppA基因的遗传进化树显示,10株分离菌均位于同一分支内;动物回归试验结果显示,在24 h内攻毒小鼠死亡率较高（21/30）,分离菌有较强的致病力。【结论】福建省猪场猪多杀性巴氏杆菌流行菌株的荚膜血清型主要是A和D型,且大部分菌株都来源于共同的祖先,本研究结果丰富了猪多杀性巴氏杆菌的流行病学资料,并为该病的防控奠定基础。     

Salmonella Isolations from Snakes and Other Reptiles

Bacteriological examination of faeces and swabs from fourteen species of reptiles predominantly constrictors, yielded six serotypes of Salmonella as well as Arizona hinshawii, Proteus species, Citrobacter freundii and Enterobacter species. Organisms isolated were identified using conventional bacteriological methods and yielded two serotypes of salmonellae not previously identified in Canada: Salmonella nima and Salmonella 58:a.     

猪源D型产毒素多杀性巴氏杆菌毒素基因的原核表达

参照GenBank收录的产毒素多杀性巴氏杆菌toxA基因序列(AF240778),设计一对引物,从猪源D型产毒素多杀性巴氏杆菌中扩增出toxA编码区3 858 bp的片段,将其克隆至原核表达载体PET-32a,转入大肠埃希菌BL21(DE3)中进行融合表达多杀性巴氏杆菌毒素。SDS-PAGE和Western blot分析证实,该表达产物以包涵体形式存在,大小约175 ku。动物试验结果表明,重组蛋白具有良好的免疫原性、反应原性及一定的生物学活性。通过间接ELISA方法检测抗毒素的猪阳性血清,表达重组蛋白较天然蛋白具有更高的特异性,为多杀性巴氏杆菌毒素进一步应用奠定了基础。     

猪多杀性巴氏杆菌的分离鉴定及生物学特性研究

用PCR方法配合生化鉴定，从有肺炎症状猪的肺脏及进行性萎缩性鼻炎(Progressive atrophic rhinitis，PAR)症状猪的鼻拭子中分离出66株多杀性巴氏杆菌(Pasteurella multocida，Pm)。然后做了药敏试验，并用PCR方法对这66株Pm进行分型及毒素基因的检测，用豚鼠皮肤坏死试验及小鼠致死试验对产毒素多杀性巴氏杆菌(Toxigenie Pasteurella multocida，T^ Pm)进一步鉴定。结果显示PCR鉴定与生化鉴定Pm结果完全一致；PCR分型表明有46株为D型Pm，18株为A型：Pm，1株为B型Pm，1株无法定型；有8株用PcR检测为T^ Pm；豚鼠皮肤坏死试验及小鼠致死试验对这8株T^ Pm的进一步鉴定也表明均为产毒素菌株。所鉴定的8株T^ Pm都为D型，都分离于有严重PAR症状的猪。     

Deoxyribonucleic acids from Pasteurella multocida and Pasteurella haemolytica]

Pasteurella multocida and P. haemolytica strains contain between 1.5 and three per cent phosphorus, between nine and 14 per cent nitrogen, between two and four per cent DNA, and between five and 18 per cent RNA, the precise figures depending on culturing conditions. High-molecular DNA may be isolated by means of bacteriolysis, using deoxycholate or dodecylsulphate and the usual steps of purification, with yield and purity differing by strains. DNA with sufficient purity can be obtained from Sepharose 2 B by gel chromatography. The isolated DNA yields were characterised, base values being between 37 and 38 per cent GC for P. haemolytica and between 41 and 48 per cent GC for P. multocida. Highly suitable precursors to DNA synthesis for tritium labelling are 3H-thymidine, which is incorporated in excess of 3H-thymine by a factor of 255, as well as 3H-uracil, with its activity being recovered also from the pyrimidine bases of DNA via pyrimidine biosynthesis.     

巴氏杆菌引起猪肾脏局灶性病变的检疫处理

近几年来,在生猪定点屠宰检疫过程中,多次发现猪肾脏被膜剥离后表面呈现一种独特的“圆环状出血病灶”,我们针对这一现象进行进一步剖检,跟踪分析、涂片镜检和细菌培养,现将检疫结果报告如下,供同行参考,以避免误检的发生。1基本情况生猪来源于我市及周边地区的养殖规模小区,对每一批猪严格宰前检疫,查验三证、免疫标识、群体检疫、个体检疫等;对宰后在初检部位发现的35例局灶性病变肾脏的胴体、内脏、淋巴结进行感观检查和剖检分析。2感观检查2.1仅病变部位和个别肾脏有质脆、色泽苍白或点状出血等变化,其它绝大部分肾色泽大小弹性等方面均…     

湖南省屠宰场生猪肺线虫感染情况调查

为了解湖南省生猪肺线虫的感染情况和危害程度,控制该虫的流行,对3个屠宰场猪进行解剖,采用常规的寄生虫实验室检查法检查气管、支气管、细支气管、肺脏等处的虫体。所获虫体用75%酒精保存,统计感染强度,计算感染率。检测结果显示,3个屠宰场生猪肺线虫感染率A(5.93%)B(4.26%)C(4.18%)。结果表明,湖南省生猪有肺线虫感染,应引起注意。     

Pasteurella haemolytica serotypes from pneumonic goatlungs

Extract

Madam:– The significance of Pasteurella haemolytica as a pathogen of cattle and sheep is well established. However, less attention has bcen paid to its role as a pathogen of goats and this limited work relates mainly to tropical countries. (2)(3)(4)(5) The lack of information on this topic and the increase in economic importance of goats in New Zealand led us to undertake a preliminary survey to find which of the 15 serotypes of P. haemolytica are commonly isolated from pneumonic goats in this country.