猪链球菌病的诊断与防控

一、病原 能引起猪链球菌病的病原复杂,主要有马链球菌兽疫亚种(Streptococcus equi subsp equi)、猪链球菌(Streptococcus suis)、马链球菌类马亚种(Streptococcus equisubsp equi similis)以及兰氏分群中D、E、L群的链球菌等.尽管在临床上也常常能分离到其它的链球菌,但我国流行的主要病原为马链球菌兽疫亚种和猪链球菌2型.     

猪链球菌病疫苗研究进展

猪链球菌病是由多种猪源链球菌所引起的猪的多种病症的总称.其病原包括C群马链球菌兽疫亚种(简称C群菌)、猪链球菌(主要有致病性较强的猪链球菌2型(简称SS2),猪链球菌9型(简称SS9))以及D群和E群链球菌等.临床表现为急性死亡、急性败血症、脑膜炎、关节炎、心内膜炎、多发性浆膜炎、肺炎、母猪流产以及化脓性淋巴结炎、颊部或颈部脓肿等.     

猪链球菌病及其疫苗研究进展

猪链球菌病(Streptococcosis suis)是由多种不同群的链球菌引起的不同临诊症状传染病的总称〔1〕。该病以导致猪败血症、化脓性淋巴结炎、脑膜炎、关节炎为主要特征,在某些特定诱因作用下,发病猪群死亡率可达80%左右。我国将猪链球菌病列为二类动物疾病〔1,2〕。近年来,我国南方大部分地区发生和流行的猪链球菌病的主要病原是猪链球菌2型(Streptococcus suis type2)及马链球菌兽疫亚种(Streptococcusequine subspecies.zooepidemicus)。本文着重对这2种不同型猪链球菌的病原学、流行病学及疫苗的研究近况进行了综述。1病原学猪链球菌为需…     

猪败血性链球菌(ST171)疫苗生产工艺研究

猪链球菌病(swine streptococosis)是由链球菌属中致病性链球菌所致的一种传染病。目前,以C群兽疫链球菌病和D群中的2型链球菌病影响最严     

D群猪链球菌的分离鉴定

我国猪链球菌病病原主要有C、D、E、L、R、S等群。陈永林等(1993)对国内126株致病性猪链球菌进行了分群鉴定,其中C群兽疫链球菌约占72.22%,D群占7.14%,S和R群只占4.76%,E、H、T仅各占0.79%,尚未鉴定出L群(曾智勇等,2005)。猪链球菌病是分布范围极广的猪传染病,世界许多国家都有     

猪链球菌病的诊断与防控

一、病原 能引起猪链球菌病的病原复杂，主要有马链球菌兽疫亚种（Streptococcus equi subsp equi）、猪链球菌（Streptococcus suis）、马链球菌类马亚种（Streptococcus equi subsp equisimitis）以及兰氏分群中D、E、L群的链球菌等。尽管在临床上也常常能分离到其它的链球菌，但我国流行的主要病原为马链球菌兽疫亚种和猪链球菌2型。     

猪链球菌病的防治

猪链球菌病是近年来流行于世界许多国家的一种传染病，其病原体主要是C群兽疫链球菌（Stneptocaccus，Zooepidcmicus）和马链球菌（S.equisimilis），D群猪链球菌（S.suis）、L群链球菌及E群链球菌也可使猪致病。本文对其临床症状、病理变化、诊断方法、治疗方法及防治措施加以阐述。     

猪链球菌2型引致的猪链球菌病

2005年6月至8月间在四川暴发的导致猪和人死亡的猪链球菌病,是由致病性链球菌2型感染引起的一种人畜共患病.根据<中华人民共和国动物防疫法>及其有关规定,猪链球菌病为二类动物疫病.多种猪源链球菌均可导致猪链球菌病,可致病的猪源链球菌中,最常见的是猪链球菌2型及马链球菌兽疫亚种(旧称兽疫链球菌).前者能导致猪急性败血死亡,同时又能感染皮肤有伤的人群并致死,后者一般只对猪及其它动物致病猪链球菌病的临床表现.无论哪一种猪源链球菌引起的猪链球菌病在临床上都有猪败血性链球菌病和猪淋巴结脓肿两种表现,其主要特征是败血症、化脓性淋巴结炎、脑膜炎以及关节炎,其中以败血症的危害最大,在某些特定诱因作用下,发病猪群的死亡率可以达到80%.     

猪链球菌病疫苗研究进展

猪链球菌病是由多种猪源链球菌所引起的猪的多种病症的总称。其病原包括C群马链球菌兽疫亚种（简称C群菌）、猪链球菌（主要有致病性较强的猪链球菌2型（简称SS2）、猪链球菌9型（简称SS9））以及D群和E群链球菌等。临床表现为急性死亡、急性败血症、脑膜炎、关节炎、心内膜炎、多发性浆膜炎、肺炎、母猪流产以及化脓性淋巴结炎、颊部或颈部脓肿等。近年来,猪链球菌病在我国呈现不断上升的趋势,不仅可以直接致病,而且是猪病混合感染和（或）继发感染的常见病原,     

猪链球菌病病原分群鉴定和药敏试验

从新郑、洛阳、中牟、新乡等16个县(市)猪场病料中,检出并分离到16株链球菌,对其进行了系统的生化分群鉴定试验和药敏试验。生化分群鉴定试验结果表明,我省发生的猪链球菌病是由E群链球菌(6/16)、D群猪链球菌(4/16)、C群兽疫链球菌(3/16)、L群链球菌(2/16)和未知群(1/16)链球菌引起的,其分布无明显的区域性。药敏试验结果表明,大多数菌株对利复平、氧氟沙星、青霉素敏感;对头孢唑啉、卡那霉素次之;对杆菌肽、复方新诺明等耐药。     

Streptococcus equi bacteriophage SeP9 binds to group C carbohydrate but is not infective for the closely related S. zooepidemicus

Streptococcus equi (S. equi subsp. equi) is widely believed to have evolved from an ancestral strain of S. zooepidemicus (S. equi subsp. zooepidemicus) based on high sequence homology. A striking difference is the absence of phage sequences from S. zooepidemicus. In this study we show that the receptor for SeP9, a temperate bacteriophage of S. equi, is the Lancefield group C carbohydrate. However, although SeP9 binds to group C carbohydrate from S. zooepidemicus, it appears not to replicate and produce plaques.     

Results of bacteriological and cytological examinations of the endometrium of subfertile mares in stud farms in Serbia

Uterine microbiology, antimicrobial susceptibility and endometrial cytology were investigated in a total of 51 mares with fertility problems from 16 different stud farms in Serbia. Uterine cultures were performed after collection with a double guarded uterine swab, and endometrial cytology was evaluated after collection of endometrial cells with a special device (cytology brush). In 21 of 51 mares, at least one bacterial species was isolated from the uterus; the most frequent were Streptococcus equi subsp. zooepidemicus (13 isolates) and E. coli (four isolates). All isolates of Streptococcus equi subsp. zooepidemicus were susceptible to penicillin. Results from endometrial cytology were inconsistent; in 17 animals with positive bacteriological culture, cytology was not altered. It can be concluded that in Serbia, as in many other contries, Streptococcus equi subsp. zooepidemicus is the main cause for equine endometritis. It can be easily diagnosed by uterine culture but endometrial cytology does not always prove the existence of an endometrial infection with this agent.     

Real-time PCR for detection and differentiation of Streptococcus equi subsp. equi and Streptococcus equi subsp. zooepidemicus

Strangles is a contagious equine disease caused by Streptococcus equi subsp. equi. In this study, clinical strains of S. equi (n=24) and Streptococcus equi subsp. zooepidemicus (n=24) were genetically characterized by sequencing of the 16S rRNA and sodA genes in order to devise a real-time PCR system that can detect S. equi and S. zooepidemicus and distinguish between them. Sequencing demonstrated that all S. equi strains had the same 16S rRNA sequence, whereas S. zooepidemicus strains could be divided into subgroups. One of these (n=12 strains) had 16S rRNA sequences almost identical with the S. equi strains. Interestingly, four of the strains biochemically identified as S. zooepidemicus were found by sequencing of the 16S rRNA gene to have a sequence homologous with Streptococcus equi subsp. ruminatorum. However, they did not have the colony appearance or the biochemical characteristics of the type strain of S. ruminatorum. Classification of S. ruminatorum may thus not be determined solely by 16S rRNA sequencing. Sequencing of the sodA gene demonstrated that all S. equi strains had an identical sequence. For the S. zooepidemicus strains minor differences were found between the sodA sequences. The developed real-time PCR, based on the sodA and seeI genes was compared with conventional culturing on 103 cultured samples from horses with suspected strangles or other upper respiratory disease. The real-time PCR system was found to be more sensitive than conventional cultivation as two additional field isolates of S. equi and four of S. zooepidemicus were detected.     

猪链球菌2型仔猪感染动物模型的建立及免疫保护试验

采用猪繁殖与呼吸综合征(PRRS)弱毒与猪链球菌2型协同感染仔猪的方式,建立动物感染模型,结果协同感染组试验仔猪均死亡,PRRS弱毒、猪链球菌攻毒组及空白对照组仔猪均存活.结果表明,PRRS弱毒可增强猪链球菌2型对猪的易感性.将建立的动物感染模型用于猪链球菌灭活苗(马链球菌兽疫亚种 猪链球菌2型)的效力检验,结果灭活苗可以保护PRRSV与链球菌的协同感染.     

马源马链球菌兽疫亚种新疆株的分离鉴定及遗传特性分析

为了解马源马链球菌兽疫亚种（S.zooepidemicus）新疆分离株马链球菌兽疫亚种类M蛋白（SzM）基因的分子进化与变异情况,为该菌引起的感染性疾病的防控提供依据,本试验对新疆地区某马场采集的病马淋巴结样品进行病原菌的分离培养和生化鉴定,并对分离菌株进行药物敏感性试验。根据已发表的马源SzM基因序列设计引物,对其SzM基因进行PCR扩增及序列测定。将获得的SzM序列与GenBank中不同动物源马链球菌兽疫亚种分离株序列进行同源性比对和遗传进化分析。结果显示,分离得到了一株革兰氏阳性链球菌,将其命名为马链球菌兽疫亚种ZMSY15-1。药物敏感性试验结果表明,分离菌株对青霉素、磺胺嘧啶钠耐药,对其他14种药物均敏感。序列分析结果显示,马链球菌兽疫亚种ZMSY15-1与国内外不同动物源分离株SzM基因氨基酸同源性为56.0%~70.0%。遗传进化分析结果显示,这些菌株可分为4个群。马链球菌兽疫亚种ZMSY15-1与猪源分离株SzM蛋白的氨基酸同源性为59.9%,分别属于2个不同的群,其与美国马源分离株NH55426亲缘关系最近。本试验结果可丰富国内马源马链球菌兽疫亚种SzM基因的信息数据,为马链球菌兽疫亚种的致病机制研究和预防控制提供参考依据。     

马链球菌兽疫亚种类M蛋白亚单位疫苗小鼠免疫试验

为获得控制猪链球菌病安全高效的疫苗，本试验进行了马链球菌兽疫亚种类M蛋白亚单位疫苗的研制。应用热酸法提取马链球菌兽疫亚种ATCC35246株类M蛋白，并分别采用羟基磷灰石（HAT）层析和冷酒精沉淀法进行纯化，结果得到较纯的类M蛋白。用热酸提取的粗制类M蛋白、2种纯化的类M蛋白及全菌苗免疫小鼠，结果保护率分别为92％（11／12）、100％（12／12）、100％（12／12）和83％（10／12），表明类M蛋白亚单位疫苗有进一步开发的必要。     

Proline-glutamic acid-proline-lysine peptide set as a specific antigen for the serological diagnosis of strangles

The reactivity of synthesised peptide sets for the M-like proteins SeM and SzPSe with sera from horses infected with Streptococcus equi or Streptococcus zooepidemicus, or control horses, was investigated by an ELISA. Seventeen horses were infected experimentally with S equi or S zooepidemicus, convalescent sera were obtained from 25 horses and control sera were obtained from 1945 horses. The serum antibody responses of individual horses to the peptide sets were highly variable. Some of the peptide sets for SeM reacted strongly with the sera from the horses infected experimentally with S equi, but also reacted with sera from some of the horses infected experimentally with S zooepidemicus. However, the proline-glutamic acid-proline-lysine (PEPK) repeats peptide set, synthesised from the PEPK repeats areas of SzPSe, reacted most strongly with the sera from the horses infected experimentally with S equi and the horses convalescing from strangles, and reacted only minimally with the sera from the horses infected experimentally with S zooepidemicus and the control horses.     

Proliferation of Streptococcus zooepidemicus and Pseudomonas aeruginosa within a simulated subpalpebral lavage flushed with equine serum

Objective  To evaluate whether equine serum administered via a simulated subpalpebral lavage system (SPL) supports proliferation of Streptococcus zooepidemicus or Pseudomonas aeruginosa within the tubing.
Procedures  A sterile i.v. catheter with injection cap was inserted into sterilized silicone tubing (Mila^®). To mimic an SPL within the dorsal conjunctival fornix, the tubing was secured to an elevated platform. The tip of the tubing extended from the platform into a vial containing culture medium just inoculated with approximately 1.5 × 10⁸ CFU/mL P. aeruginosa or S. zooepidemicus . To mimic administration of medication, the tubing was infused twice daily with equine serum, sterile saline (negative control), or culture medium (positive control) followed by air. Incubation was at 25 or 37 °C. At 24, 48, and 72 h postinoculation, samples were obtained for bacterial culture from one simulated SPL for each experimental variant. The following sections were cultured: (i) tubing tip previously submerged in the inoculated culture medium, (ii) tubing mid-section, and (iii) tip of the i.v. catheter. The experiment was performed in triplicate.
Results  Streptococcus zooepidemicus or P. aeruginosa were isolated from 100% of the tubing tips. Streptococcus zooepidemicus was isolated from one mid-section flushed with culture medium incubated at 37 °C. All other samples were negative for growth of the inoculated agents.
Conclusions  Streptococcus zooepidemicus and P. aeruginosa did not proliferate within silicone tubing infused with equine serum. These data suggest that topical serum can be safely administered through a superiorly placed SPL in clinical cases.     

Chronic endometritis in an Asian elephant (Elephas maximus).

A 48-yr-old female Asian elephant with a history of pododermatitis developed recurrent hematuria beginning in 2002. Transrectal ultrasonography and endoscopic examination in 2004 identified the uterus as the source of hematuria and excluded hemorrhagic cystitis. Treatment with Desloreline implants, antibiotics, and homeopathic drugs led to an improved general condition of the elephant. In July 2005, the elephant was suddenly found dead. During necropsy, the severely enlarged uterus contained about 250 L of purulent fluid, and histopathology revealed ulcerative suppurative endometritis with high numbers of Streptococcus equi ssp. zooepidemicus and Escherichia coli identified on aerobic culture. Additional findings at necropsy included: multifocal severe pododermatitis, uterine leiomyoma, and numerous large calcified areas of abdominal fat necrosis. Microbiologic culture of the pododermatitis lesion revealed the presence of Streptococcus agalactiae, Streptococcus equi ssp. zooepidemicus, Staphylococcus sp., Corynebacterium sp., and Entercoccus sp.