猎链球菌2型上海分离株的病原特性鉴定

1997年底上海地区分离到一株猪链球菌2型，结合培养特性、生化特性、血清定型及动物试验等对其进行了鉴定。其形态、染色及培养基本符合链球菌的特点，具有β溶血，生化试验结果不稳定，用国际通用的链球菌A-C乳胶分型诊断液检测分离株，不在其检测范围，但能凝集猎链球菌2型标准阳性血清，人工接种4日龄乳鼠和猪有致病性，本试验对上海地区首次分离的猪链球菌2型菌株进行了病原特性鉴定，证实猪链球菌2型在上海存在，为今后防治猪链球菌病提供了可靠的科学依据。     

广西猪源链球菌分离株的分群鉴定

从广西南宁、玉林、来宾、柳州、钦州等9个市29个猪场的送检材料中,分离出95株猪链球菌.使用链球菌乳胶凝集标准诊断试剂盒(有兰氏A-G群)对其中56株典型链球菌进行了培养特性、生化试验和血清分群鉴定.结果有32株为D群链球菌,9株为C群链球菌,1株为F群链球菌,5株为G群链球菌,1株与C群和D群有交叉反应,2株与D群和G群有交叉反应,6株未能定群.小白鼠对56株分离菌的敏感性有所不同.本试验结果表明,广西地区猪链球菌病的病原已不是单一血清群,同一猪场存在着多种血清群的链球菌.这为猪链球菌病的防制提供重要依据.     

猪链球菌2型JX分离株的生物学特性

从临床表现为脑膜炎、关节炎及败血症的发病猪分离到2株细菌，分别命名为JX02和JX03，经鉴定其形态、染色及培养特性均符合链球菌的特点，具α或β溶血，生化试验结果不稳定。用猪链球菌2型、1型和9型抗血清进行凝集试验，结果2株菌均能与猪链球2型抗血清凝集，其中1株菌对小鼠和家兔均有致病性，另1株菌只能致死家兔。PCR均能扩增2株菌的主要毒力因子基因。表明发病猪的病原不同于以往的C群链球菌，不是马链球菌兽疫亚种，而是属于R群的猪链球菌。     

猪源链球菌的分离与鉴定

从浙江地区98例发病样品猪猪体共分离到56(57％)株猪源链球菌，对12株典型分离株进行培养特性、生化特性及血清型的鉴定，多数具α或β溶血，其中C群链球菌8株。L群链球菌1株，2型猪链球菌2株。未定群1株。小鼠对12株分离株的敏感性有一定的差异。结果表明：浙江地区分离到的猪链球菌已不是单一的C群链球菌，且C群中也不是以往的马链球菌兽疫链球菌亚种。而是停乳链球菌似马亚种。并首次分离到猪链球菌2型。     

冀东地区猪链球菌病病原的特性

对2003－2004年从河北省秦皇岛、唐山分离获得的48株猪源链球菌，进行了生物学特性鉴定及血清分群。其形态、染色及培养特性基本符合链球菌特征，大多具有α或β溶血。用国际通用的链球菌A-G乳胶分型诊断液检测48株分离菌．结果表明，猪源链球菌血清群以兰氏D群为主，占47．9％（23／48），其次为C群，占37．5％（18／48），A群、B群各1株，其他5株未检测出。致病性试验表明，供试菌株均能使小鼠、家兔和猪感染发病甚至死亡。试验提示，冀东地区猪链球菌病的病原以兰氏D群为主，在防治方面应引起重视。     

从非法屠宰的猪肉中检出猪链球菌2型

从送检的非法屠宰的猪肉中分离到1株链球菌,结合其培养特性、生化特性、血清定型、PCR鉴定、动物实验等对其进行了鉴定。用国际通用的链球菌乳胶分型诊断液检测,结果表明其不属于链球菌兰氏分群的A～G群。但它凝集猪链球菌2型标准阳性血清,三重PCR扩增及测序结果表明其为猪链球菌2型。分离菌具有猪链球菌2型的CPS、MRP、EPF、SLY、ORF2五种主要毒力因子;将分离株人工静脉注射新西兰兔4只,均在12～24h均死亡,腹腔注射8只BALB/c小鼠后,3周内死亡5只,3只未死亡。     

猪链球菌病病原分离鉴定及防治试验

从20份疑似猪败血型链球菌病和神经型链球菌病的病料中分离到12株细菌,通过培养特性、菌落形态、染色特性、生化试验及血清学试验确定为C群兽疫链球菌7株,D群猪链球菌5株。药敏试验证明分离菌对先锋霉素Ⅴ、阿米卡星最敏感,经临床应用效果良好。用分离菌株研制成二价氢氧化铝胶灭活苗能有效地预防猪链球菌病。     

猪链球菌病病原分离鉴定及防治

从20份疑似猪败血型链球菌病和神经型链球病的病料中分离到12株细菌,通过培养特性、菌落形态、染色特性、生化试验及血清学试验确定为C群兽医链球菌7株,D群猪链球菌5株.药敏试验证明分离菌对先锋霉素V、阿米卡星敏感,经临床应用效果良好.用分离菌株研制成二价氢氧化铝胶灭活苗能有效地预防猪链球菌病,临床应用免疫保护率可达90%以上.     

昆明地区猪源链球菌分离株血清群检测及致病病型分析

从昆明地区可疑病料中分离出12株猪源致病性链球菌,对其进行了血清群鉴定。结果表明分离菌株中以兰氏D群为主,其次为C群。其中D群4株(33.3%),C群3株(25%),A群1株(8.3%),E群1株(占8.3%),未能定群3株(25%)。分离株cg1为猪链球菌2型。通过对临床病例血清型检测显示,猪链球菌病在昆明地区广泛存在,尤以寒冷季节多发,主要病型包括败血型、脑膜炎型和关节炎型。     

四川省猪链球菌的分离与鉴定

从41份病、死猪病料中分离到SC1-SC19 19株细菌，结合培养特性和生化特性鉴定为猪链球菌，通过玻片凝集试验，用猪链球菌2型阳性血清将最初分离出来的4株菌（SC1-SC4）鉴定为猪链球菌2型。同时还进行了动物试验和药敏试验，为及时有效地控制疫情提供了科学依据。     

猪链球菌的分离与鉴定

文章对分离的4株猪源链球菌进行了鉴定，其形态，染色、培养及生化特性均符合链球菌的特点。用链球菌乳胶分型诊断液检潮上述分离株，均不在其检测范围，即不属于链球菌兰氏分群的A-G群，但它们凝集猪链球菌2型抗血清。分离株对小鼠不致病，而对家兔则可致病。     

猪Ghrelin基因的克隆及原核表达

从猪下丘脑、胃等组织中提取总RNA，根据已发表的猪的Ghrelin mRNA序列设计合成引物，通过RT-PCR进行cDNA扩增，获得了282bp的片段。将该片段克隆于pMD-18T载体后进行序列分析，确认PCR产物为Ghrelin cDNA。从阳性克隆中提取质粒，经NheⅠ和XhoⅠ双酶切，回收282bp的目的片段，定向克隆到pET-28a表达载体中，提取质粒并再次转化到BL21（DE3）中，成功地筛选出阳性克隆。经IPTG诱导阳性菌，通过SDS-PAGE检测出猪Ghrelin基因的表达．     

Production of muraminidase-released protein (MRP), extracellular factor (EF) and suilysin by field isolates of Streptococcus suis capsular types 2, 1/2, 9, 7 and 3 isolated from swine in France

A total of 323 isolates of Streptococcus suis recovered from diseased or healthy pigs in France were serotyped. The presence of virulence-related proteins, Muraminidase-Released Protein (MRP), Extracellular Factor (EF) and Suilysin was also studied in 122 isolates of capsular types 2, 1/2, 9, 7 and 3 to evaluate their implication in virulence of S. suis. Capsular types 2, 1/2, 9, 7 and 3 were the most frequently detected (93%), with 69% for the capsular type 2 alone. Capsular types 2, 1/2, 9, 7, 3, 1, 4, 8, 18, 10 and 12 were isolated from diseased pigs, whereas types 2, 7, 9, 1/2, and 3 originated from the nasal cavities or tonsils of healthy animals. Most of the S. suis type 2 isolates recovered from diseased pigs carried MRP+ EF- Suilysin- (46%) or MRP+ EF+ Suilysin+ (28%) phenotypes. The MRP+ EF- Suilysin- phenotype was also detected in 67% of S. suis type 2 strains isolated from healthy pigs. The production of the virulence-related proteins was less frequently found in S. suis types 1/2, 9, 7 and 3 recovered either from diseased or healthy pigs. In this study, all the capsular type 1/2 strains were MRP+ EF- Suilysin- and all the S. suis type 7 harboured an MRP- EF- Suilysin- phenotype. The MRP- EF- Suilysin- phenotype was found in S. suis types 2, 3, 7 and 9 isolated from septicaemia, meningitis, pneumonia, and pleurisy. These results suggest that the presence of these proteins should not be used as a single condition for classifying the virulence of a field isolate in France.     

猪链球菌2型的分离鉴定及致病性试验

从全国部分猪场采集疑似猪链球菌感染病例脑样品20份进行细菌分离,成功分离到10株细菌,通过猪链球菌及血清类型鉴定,最终确定其中一株为2型猪链球菌。应用猪链球菌7种主要毒力因子特异性基因扩增检测方法检测所分离到的2型猪链球菌的毒力因子分布情况,并应用小鼠攻毒试验对其致病性进行观察研究。结果表明:分离的2型猪链球菌具备7种毒力因子;动物试验表明SS2能引起小鼠的急性败血症及脑膜炎;细菌回归试验结果表明,试验组死亡小鼠的脑、心脏、肝脏、脾脏、肺脏、肾脏均有细菌定植,且能分离出攻毒菌。此分离菌株的研究为研制2型猪链球菌病疫苗奠定了基础。     

Isolation of Streptococcus suis from diseased pigs in Canada

A total of 260 isolates of streptococci collected over a 9-year period from diseased pigs submitted for necropsy were studied. Seventy-seven percent of isolates were identified as S. suis and 32% of S. suis isolates were retrieved in pure culture. S. suis was found more frequently in lungs and was often isolated in conjunction with Actinobacillus pleuropneumoniae, Pasteurella multocida, Escherichia coli and other microorganisms. A total of 151 (76%) of S. suis isolates could be serotyped within the 9 recognized serotypes. Serotype 2 was the most prevalent with 33%, followed by serotypes 3, 5 and 7. All isolates were sensitive to ampicillin, penicillin, cephradine, chloramphenicol and trimethoprim-sulfamethoxazole. Resistance to streptomycin, neomycin and tetracycline appeared to be very high.     

Streptococcus suis infection in swine. A sixteen month study.

A total of 349 isolates of Streptococcus suis retrieved from different tissues from diseased pigs were examined in this study. Only 48% of them could be categorized as one of serotypes 1 to 8 and 1/2. Among typable isolates, serotype 2 was the most prevalent (23%), followed by serotype 3 (10%). The majority of all isolates originated from lungs, meninges/brain, and multiple tissues. Forty-one percent of typable isolates and 33% of untypable isolates were retrieved in pure culture. Other isolates were found in conjunction with Pasteurella multocida, Escherichia coli, Actinobacillus pleuropneumoniae, Actinomyces pyogenes, and other streptococci. Typable S. suis isolates were more frequently isolated from pigs between five and ten weeks of age, while untypable isolates were mostly found in animals aged more than 24 weeks. No obvious monthly and/or seasonal variation of the prevalence of isolation of S. suis could be detected.     

Streptococcus suis infections in pigs in the Netherlands (Part I)

Data are presented on the incidence of various streptococcal infections in pigs in the Netherlands. 314 Strains isolated in the course of routine post-mortem diagnosis were examined. The most frequently occurring streptococcus was S. subacidus (bio) type II which was isolated in 31.2% of the cases. S. suis type 2 (Serogroup R) and S. equisimilis (Serogroup C) constituted 16.2% and 13.7% of the isolates respectively. Besides meningitis, endocarditis and polyserositis S. suis type 2 infections may frequently be associated with pneumonia (42%). The biochemical profiles of the various S. suis and S. subacidus (bio) types are presented. The profile of both species is almost identical. It seems justified to use the name S. suis for strains with this characteristic profile and to abandon the name S. subacidus. Haemolysis does not appear to be a suitable characteristic to screen for S. subacidus/S. suis types. In comparing three serological methods for typing S. suis type 2, gel precipitation using Fuller's extract and slide agglutination give an almost 100% correlation. These two methods are recommended for serotyping.     

Serotyping of Haemophilus pleuropneumoniae in the Netherlands: with emphasis on heterogeneity within serotype 1 and (proposed) serotype 9

Four hundred and forty-three Dutch field isolates of Haemophilus pleuropneumoniae were serotyped by rapid slide agglutination (RSA) using specific antisera against serotypes 1 to 5 and against the recently proposed types 6 to 9. The predominant serotypes were 9 (49%) and 2 (32%). Serotypes 1, 3, 5, 7 and 8 were isolated in small numbers: together they accounted for 3% of the total. Five percent of the isolates were not typable either due to autoagglutination or because they were not agglutinated by any of the available antisera. The remaining 49 strains (11%) agglutinated in more than one antiserum and could therefore not be properly classified. Forty-four of these 49 strains agglutinated in both anti type 1 and anti type 9 serum. Antigenic relationships between serotype 1, serotype 9 and isolates reacting with both antisera were studied using immunodiffusion and RSA with adsorbed sera. Serotype 9 strains appeared not to be a homogenous group. Isolates agglutinating exclusively in anti type 9 serum can be divided into two groups: one closely related and another hardly related to serotype 1. Serotype 9 reference strain 13261 belongs to the latter. Type 1 + 9 strains have antigens in common with serotypes 1 and 9, but they also have their own specific antigenic material. Such strains are proposed as a new serotype 10.