摘要
猪链球菌是一种能引起猪发生脑膜炎、心内膜炎和关节炎等疾病的病原菌。猪链球菌2型(SS2)引起的疾病不但给养猪业造成严重经济损失,也给公共卫生和食品安全带来了威胁,已成为全球关注的人兽共患病。了解浙江地区临床健康猪和病猪中猪链球菌2型的携带情况、主要毒力基因分布、构建2型猪链球菌资源库以及建立预警体系,对该病的防制和保障相关从业人员的健康等方面具有重要意义。到目前为止,还没有一个针对SS2的理想动物模型,对SS2致病机理方面的研究尚不够深入,不同毒力菌株的感染力和感染持续时间不是十分清楚,影响了对该菌致病机制的研究。因此,建立一种能模拟自然感染发病动物临床症状和病理变化的动物模型,以深入研究其感染的体内动态分布、感染机制,该模型的建立对SS2的研究具有十分重要意义。
(1)应用三重PCR方法,对浙江地区临床健康待宰猪和病猪中猪链球菌带菌的情况进行监测与分析,明确了二者猪链球菌的携带情况,对SS2主要毒力基因mrp、ef和sly分布进行进行序列分析。临床健康猪和病猪中SS及SS2分离率相近,前者SS分离率为8.85%,SS2分离率为0.44%；后者SS分离率为8.85%,SS2分离率为0.64%；所有的SS2菌株都含有mrp,而部分菌株则缺失ef和sly；与资阳SS2分离株05ZYH33相比,实验室部分分离株的mrp、ef和sly基因的核苷酸和氨基酸序列同源性与其都很高(>99%)。
(2)猪链球菌2型免疫抑制BALB／C小鼠动物感染模型的建立和体内的分布。本实验选用免疫抑制BALB／C小鼠为实验动物,该小鼠具有体型小、方便饲养、成本低和易于管理等优点。实验采用猪链球菌2型分离株JX1105和JX0301为攻毒菌株,通过腹腔感染免疫抑制BALB／C小鼠,建立猪链球菌2型感染免疫抑制BALB／C小鼠的动物模型。结果显示：猪链球菌2型可人工感染免疫抑制BALB／C小鼠,症状明显,其临床症状和病理变化等表现与猪自然状态发病相似,模型重复性好。分别于攻毒后第6h、12h、24h、48h、72h、96h、120h剖检观察其病理变化规律,利用细菌分离及PCR方法检测SS2在体内各组织中的分布情况和变化规律。实验发现SS2侵入血液的速度很快；进入肝脏、肺脏、肾脏等实质器官要稍慢；进入脑的时间最慢,说明细菌可能只有突破血脑屏障才能进入大脑。
(3)不同毒力SS2菌株的感染力和感染持续时间。按照建立模型的攻毒方法和分组,攻毒后分别于6h、12h、24h、48h直到第168h观察临床症状,并无菌采血和分离肝脏,利用细菌平板计数和荧光定量PCR方法来检测血液中SS2的变化规律,用平板计数法检测小鼠肝脏中细菌变化规律。实验发现SS2进入血液和肝脏的速度很快,攻毒后6h左右即可在血液中检测到SS2,并在攻毒后24h或48h浓度达到高峰,随后开始减少,攻毒后120h血液中的SS2的数量快速减少甚至消失。本实验建立的荧光定量PCR方法灵敏、准确,可有效排除杂菌的影响。
Streptococcus suis is an important pathogen that can cause meningitis, endocarditis, arthritis and other infections in pigs throughout the word. The disease coused by Streptococcus suis type 2 had become one of the most important Amphixenosis worldwide focused, for it did not only cause the big economic loss in swine farming, but brought great threaten/threats to the public health and food security as well. The isolation rates of Streptococcus suis serotype 2 for pigs in Zhejiang area and the distribution of important virulence gene,construction of Streptococcus suis Serotype 2 resource bank and foundation of alarm system are helpful to prevent the Streptococcus suis diseases and ensure the heath of the practitioners, so far, no good animal model for Streptococcus suis Serotype 2,infectivity and duration hadn't been deeply studied Consequently, it's greatly essential to set up an animal model in which clinical symptom and pathological change are similar with that of naturally infected animals,in order to have a further study on dynamic distribution,infection mechanism,virulence factors,and immune response of SS2 infection, which was of great significance to protect and control of this disease.
(1) Triplex-PCR assay was used to examine Streptococcus suis in pigs in Zhejiang area. sequences of mrp、ef and sly gene were analysis. While 200 (8.85%) Streptococcus suis (SS) isolates and 10 (0.44%) SS2 isolates were isolated from healthy swines,157 (8.44%) SS isolates and 12 (0.64%) SS2 isolates were from diseased swines, suggesting the similar isolation rates of SS and SS2 in healthy and diseased swines. Virulence-associated genes, including mrp, ef and sly, were also detected for all 22 SS2 strains. mrp was found in all strains, whereas ef and sly were absent in some strains. However, these virulence-associated genes consistently showed high nucleotide and amino acids identities (>99%) correlation with 05ZY031.
(2) Setting up the immunosuppression BALB/C mouse SS2 infected model andThe dynamic distribution of SS2. the immunosuppression BALB/C mouse was selected as the experimental animal. It was small in body type,convenient to feed, low for cost and easy to manage. The immunosuppression BALB/C mouse was infected by JX1105 and JX0301 through intraperitoneal injection,and then infected immunosuppression BALB/C mouse model was set up. The results show that SS2 can artificially infect the immunosuppression BALB/C mouse, the symptom of infected pigs was obvious, the clinical symptom and pathological change were similar with that of naturally infected pigs, and the model had good repetitiveness. The SPF pigs were dissected and inspected for pathological change rules in 6h,12h,24h,48h,72h, 96h,120h,144h,168h after injection. The distribution and change rule of SS2 in vivo organism was detected by bacteria isolation and PCR. The experiment results indicated that SS2 could quickly invade into blood,but invading into liver, kidney, and other organon parenchymatosums was lower, SS2 could only be isolated from brain tissue but must break through blood brain barrier.
(3) Infectivity and duration of different virulence SS2 strains. Dividing groups,conteracting toxic substances according to the method used in the model. Clinic symptom was observed and blood was got axenicly 6h,12h,24h,48h,72h, 96h,120h,144h and 168h after injection.Growth and decline rules of SS2 in blood were detected by taking count and fluorescent quantitation PCR. The results show that SS2 can quickly invade into blood, SS2 could be detected in blood about at 6h after injection, and the concentration of SS2 in blood reached top at 24-48h after injection, then declined, and quickly reduced or even vanished at 120h. The fluorescent quantitation PCR method was very sensitive, precisely.
引文
[1]Higgins R, Gottschalk M. Distribution of Streptococcus suis capsular types in 1998[J]. Can Vet J 1999,40:277.
[2]Arends JP, Zanen HC. Meningtitis caused by Streptococcus suis in humans[J]. Rev. Infect. Dis. 1998,10:131-137.
[3]Trottier, S., Higgins R, Brochu G, and Gottschalk M. A case of human endocarditis due to Streptococcus suis in North America[J]. Rev. Infect. Dis,1991,13:1251-1252.
[4]BraunS, Jechart G, Emmerling U, Ehret W. Streptococcus suis meningitis, a rare occupational disease[J]. Dtsch Med Wochenschr,2007,132(20):98-100.
[5]Higgins R, Gottschalk M, Beaudoin M, Rawluk SA. Prevalence of Streptococcus suis capsular types in Quebec and western Canada[J]. Can Vet J,1992,33:27-30.
[6]Monter Flores JL, Higgins R, Allarie S. Distribution of the different capsular types of Streptococcus suis in 19 swine nurseries[J]. Can Vet J,1993,34:170-171.
[7]Gottschalk M, Higgins R, Jacques M, et al. Isolation and characterization of Streptococcus suis capsular type 9-22[J]. Vet Diagn Invest J,1991,3:60-65.
[8]Yu-Tsung Huang, Lee-Jene Teng, Shen-Wu Ho, et al. Streptococcus suis infection[J]. Microbiol Immunol Infect J,2005,38:306-313.
[9]Bin Chang, Akihito Wada, Tadayoshi Ikebe, et al. Characteristics of Streptococcus suis Isolated from Patients in Janan[J]. Jpn. J. Infect. Dis,2006,59:397-399.
[10]姚火春,陈国强,陆承平.猪链球菌1998分离株病原特性鉴定[J].南京农业大学学报,1999,22(2)：67-70.
[11]李春,张东,李金海,等.四川省猪链球菌的分离与鉴定[J].四川畜牧兽医,2005,32(9)：25-26.
[12]朱虹,何君,荆红波,等.四川省资阳市爆发得猪链球菌感染疫情中病原菌得分离和鉴定[J].微生物学报,2006,46(4)：635-638.
[13]Pancholi V, Fischetti VA. Major surface protein on group A streptococci is glyceraldehydes-3-Pho-sphate-dehydrogenase with multiple binding activity[J]. J Exp Med, 1992,176:415-426.
[14]Perch B, Kristjansen P, Skadhauge K. Group R streptococcus pathogenic for man:two case of meningitis and one fatal case of sepsis[J]. Acta Pathol Microbil Scand,1968,74:69-76.
[15]Arend SM, van Buchem MA, van Ogtrop ML, et al. Septicaemia, meningitis and spondylodiscitis caused by Streptococcus suis type 2[J]. Infection,1995,23:128.
[16]Halaby T, Hoitsma E, Hupperts R, et al. Streptococcus suis meningitis, a poacher's risk[J]. Eur J Clin Microbiol Infect Dis,2000,19:943-945.
[17]Hantson P, Vekemans MC, Gautier P, et al. Streptococcus suis meningitis in man[J]. Acta Neurol Belg,1991,91:165-168.
[18]Coolen L, Dens J, Baeck E, et al. Streptococcus suis meningitis, permanent perceptive deafness and endophthalmitis[J]. Intensive Care Med,1989,15:545.
[19]Kjems E, Perch B. Serious infection in man caused by group R streptococci[J]. Ugeskr Laeger,1975,137:682-683.
[20]Watkins EJ, Brooksby P, Schweiger MS, et al. Septicaemia in a pig-farm worker[J]. Lancet, 2001,35:357-358.
[21]Bronstein AM, Morland AB, Ruddock KH, et al. Recovery from bilateral vestibular failure: implications for visual and cervico-ocular function[J]. Acta Otolaryngol Suppl,1995, 45:222
[22]Meecham JS, Worth RC. Persistent diplopia following Streptococcus suis type 2 meningitis[J]. J R Soc Med,1992,85:579-580.
[23]Durand F, Perino CL, Recule C, et al. Bacteriological diagnosis of Streptococcus suis meningitis[J]. Eur J Clin Microbiol Infect Dis,2001,20:519-521.
[24]Francois B, Gissot V, Ploy MC, et al. Recurrent septic shock due to Streptococcus suis[J]. J Clin Microbiol,1998,36:2395.
[25]Tayorol J, Besnier JM, Laudat P, et al. Infective endocarditis due to Streptococcus suis type 2[J]. Eur J Clin Microbiol Infect Dis,1996,15:765-766.
[26]Rosenkranz, Elsner M, Sturenburg HA, et al. Streptococcus suis meningitis and septicemia contracted from a wild boar in Germany[J]. J Neurol,2003,250:869-870.
[27]Strangmann E. Froleke H, Kohse KP, et al. Septic shock caused by Streptococcus suis:case report and investigation of a risk group[J]. Int J Hyg Environ Health,2002,205:385-392.
[28]Christensen P, Kronvall G, et al. A case of Streptococcus suis meningitis a new occupational disease in Sweden[J]. Lakartidningen,1985,82:119.
[29]Kopic J, Paradzik MT, Pandak N, et al. Streptococcus suis infection as a cause of severe illness:2 cases from Croatia[J]. Scand J Infect Dis,2002,34:683-684.
[30]Tarradas C, Luque I, de Andres D, et al. Epidemiological relationship of human and swine Streptococcus suis isolates[J]. J Vet Med B Infect Dis Vet Public Health,2001,48:347-355.
[31]Perseghin P. Bezzi G, Troupioti P, et al. Streptococcus suis meningitis in an Italian blood donor[J]. Lancet,1995,346:1305-1306.
[32]Mazokopakis EE, Kofteridis DP, Papadakis JA, et al. First case report of Streptococcus suis septicaemia and meningitis from Greece[J]. Eur J Neurol,2005,12:487-489
[33]Trottier S, Higgins R, Brochu G, et al. A case of human endocarditis due to Streptococcus suis in North America[J]. Rev Infect Dis,1991,13:1251-1252.
[34]Dickie AS, Bremner DA, Wong P Y, et al. Streptococcus suis bacteraemia[J]. N Z Med J, 1987,100:677-678.
[35]Suankratay C, Intalapaporn P, Nunthapisud P, et al. Streptococcus suis meningitis in Thailand[J]. Southeast Asian J Trop Med Public Health,2004,35:868-876.
[36]Donsakul K, Dejthevaporn C, Witoonpanich R. Streptococcus suis infection:clinical features and diagnostic pitfalls[J]. Southeast Asian J Trop Med Public Health,2003,34:154-158.
[37]Fongcom A, Pruksakorn S, Mongkol R, et al. Streptococcus suis infection in northern Thailand[J]. J Med Assoc Thai,2001,84:1502-1508.
[38]Vilaichone RK, Mahachai V, Nunthapisud P. Streptococcus suis peritonitis:case report[J]. J Med Assoc Thai,2000,83:1274-1277.
[39]Chotmongkol V, Janma J, Kawamatawong T. Streptococcus suis meningitis:report of a case[J]. J Med Assoc Thai,1999,82:922-924.
[40]Tambyah PA, Kumarasinghe G, Chan HL, Lee KO. Streptococcus suis infection complicated by purpura fulminans and rhabdomyolysis:case report and review[J]. Clin Infect Dis,1997, 24:710-712.
[41]Chan YC, Wilder-Smith A, Ong BK. et al. Adult community acquired bacterial meningitis in a Singaporean teaching hospital. A seven-year overview (1993-2000) [J]. Singapore Med J, 2002,43:632-636.
[42]Matsuo H, Sakamoto S. Purulent meningitis caused by Streptococcus suis in a pig breeder[J]. Kansenshogaku Zasshi,2003,77:340-342.
[43]Kay R, Cheng AF, Tse CY. Streptococcus suis infection in Hong Kong[J]. Qjm,1995, 88:39-47.
[44]Hui AC, Ng KC, Tong PY, et al. Bacterial meningitis in Hong Kong:10-years' experience[J]. Clin Neurol Neurosurg,2005,107:366-370.
[45]Yen MY, Liu YC, Wang JH. Streptococcus suis meningitis complicated with permanent perceptive deafness:report of a case[J]. J Formos Med Assoc,1994,93:349-351.
[46]Smith HE, Vecht U, Gielkens ALJ, et al. Cloning and nuclotide sequence of the gene encoding the 136-kilodelton surface protein of Streptococcus type 2[J]. Infect Immun,1992, 60:2361-2367.
[47]Smith HE, Reck FH, Vecht U, et al. Repeats in an extracellular protein of weakly pathogeme strains[J]. Infect Immun,1993,61(8):3318-3326.
[48]曾巧英,陆承平.猪链球菌2型溶菌酶释放蛋白诱导上皮细胞融合和凋亡[J].微生物学,2003,43(3)：408-412.
[49]曾巧英,陆承平.猪链球菌2型溶菌酶释放蛋白的黏附作用[J].南京农业大学学报,2002,25(4)：67-71.
[50]Vecht U, Wisselink HJ, Stokhole-Zuwieden N, et al. Characterizaiton of virulence of the Strepcoccus suis serotype 2 reference strain Henrichsen S735. in new born gnotobiotic pigs[J]. Vet Microbiol,1996,51(1-2):125-136.
[51]Chan YC, Wilder-Smith A, Ong BK. et al. Adult community acquired bacterial meningitis in a Singaporean teaching hospital. A seven-year overview (1993-2000) [J]. Singapore Med J, 2002,43:632-636.
[52]Matsuo H, Sakamoto S. Purulent meningitis caused by Streptococcus suis in a pig breeder[J]. Kansenshogaku Zasshi,2003,77:340-342.
[53]Kay R, Cheng AF, Tse CY. Streptococcus suis infection in Hong Kong[J]. Qjm,1995, 88:39-47.
[54]Marois C, LeDevendec L, Gottschalk M, Kobisch M. Detection and molecular typing of Streptococcus suis in tonsils from live pigs in France[J]. Can J Vet Res,2007,71(1):14-22.
[55]Jacobs AA,Loeffen PL,vandenBerg AJ,et al. Identification,purification and characterization of a thiol-activated hemolysin(suilysin)of Streptococcus suis[J]. Infect lmmun,1994, 62(5):1742-1748.
[56]Pinkney M, Beachey E, Kehoe M. The thiol-activated toxin streptolysin O does not require a thiol-group for cytolytic activity[J]. Infect Immun,1989,57:2553-2558.
[57]Staats J J, Plattner B L, Nietfeld J, et al. Use of ribotyping and haemolysin activity to identify highly virulent Streptococcus suis type 2 isolates[J]. Clin Microbiol,1998, 36:15-19.
[58]Feder I, Chengappa MM, Fenwick B, Rider M, Staats J. Partial characterization of Streptococcus suis type 2 hemolysin[J]. Clin.Microbiol,1994,32:1256-1260.
[59]Mariela S, Marcelo G. Streptococcus suis Interactions with the Murine Macrophage Cell Line[J]. infect.Immun,2002,70:4312-4322.
[60]Flanagan J, Collin N, Timoney J, et al. Characterization of the Haemolytic activity of Streptococcus equi[J]. Microb Pathog,1998,24(4):211-221.
[61]Norton PM, Rolph C, Ward PN, et al. Epithelial invasion and cell lysis by virulent strains of Streptococcus suis is enhanced by the presence of suilysin[J]. FEMS Immunol Med Microbiol,1999,26(1):25-35.
[62]陈国强,陆承平,姚火春.猪链球菌2型溶血素的提纯及其生物学特性[J].中国人兽共患病杂志,2001,17(5)：75-77.
[63]Smith HE, Reek FH, Vecht U, et al. Repeats in an extracellular protein of weakly pathogenic strains of Streptococcus suis type 2 are absent in pathogenic strains[J]. Infect Immun, 1993,61(8):3318-3326.
[64]Gotschalk M, Le brunA. Production of virulence-related proteins by Canadian strains of Streptococcus suis capsular type 2[J]. CanJ Vet Res,1998,62(1):75-79.
[65]Smith HE, Vecht U, Wisselink HJ, et al.Mutants of Streptococcus suis types 1 an 2 impaired in expression of muramidase-released protein and extracellular protein induce disease in new born germfree pigs[J]. Infect Immun,1996,64(10):4409-4412.
[66]Galina L, Vecht U, Wisselink HJ. Prevalence of various phenotypes of Streptococcus suis isolatedfrom swine in the U.S.A.based on the presence of muraminidase-released protein and Extracellular factor[J]. Can J Vet Res,1996,60(1):72-84.
[67]Benkirane R, Gottschalk M G, Dubreuil JD. Identication of a Streptococcus suis 60-KDa heat-shock protein using western blotting[J]. Microbiol, Left,1997,153(2):379-385.
[68]Benkirane R, Gottschalk M, Dubreuil JD, et al. Immunochemical characterization of an IgG-binding protein of Streptococcus suis[J]. FEMS Immunol Med Microbiol,1998, 20:121-123.
[69]Smith HE, Buijs H, Wisselink HJ, et al. Selection of virulence-associated determinants of Streptococcus suis type 2 by in vivo complementation[J]. Infect Immun,2001, 69:1961-1966.
[70]Okwumabua O, Persaud JS, Reddy PG. Cloning and Characterization of the Gene Encoding
the Glutamate Dehydrogenase of Streptococcus suis Serotype 2[J]. Clinical and Diagnostic Laboratory Immunology,2001,8:251-257.
[71]Gottschalk M.,Segura M.The pathogenesis of the meningitis caused by Streptococcus suis:the unresolved questions[J].Vet Microbiol,2000,76:259-272.
[72]Berthelot-Herault F, Cariolet R, Labbe A, Gottschalk M, Cardinal JY, Kobisch M. Experimental infection of specific pathogen free piglets with French strains of Streptococcus suis capsular type 2[J]. Can J Vet Res,2001,65(3):196—200.
[73]Sorensen, NS, Tegtmeier C, Andresen LO, et al. The porcine acute phase protein response to acute clinical and subclinical experimental infection with Streptococcus suis[J]. Veterinary Immunology and Immunopathology,2006,113(1-2):157-168.
[74]崔立,朱建国,华修国,等.猪链球菌2型四川株与江苏株对SPF猪的致病性[J].上海交通大学学报：农业科学版,2006,24(1)：54-57.
[75]Robertson ID, Blackmore DK. Experimental studies on the comparative infectivity and pathogenicity of Streptococcus suis type 2. II. Porcine and human isolates in laboratory animals[J]. Epidemiol Infect,1990, Dec;105(3):479-84.
[76]Torremorell M, Pijoan C, Dee S. Experimental exposure of young pigs using a pathogenic strain of Streptococcus suis serotype 2 and evaluation of this method for disease prevention[J]. Can J Vet Res,1999,63(4):269-75.
[77]Salles MWS, Perez-Casal J, Willson P, et al. Changes in the leucocyte subpopulations of the palatine tonsillar crypt epithelium of pigs in response to Streptococcus suis type 2 infection[J]. Veterinary Immunology and Immunopathology,2002,87(1-2):51-63.
[78]Galina L, Pijoan C, Sitjar M, et al. Interaction between Streptococcus suis serotype 2 and porcine reproductive and respiratory syndrome virus in specific pathogen-free piglets[J]. The Veterinary Record;Vet Rec,1994,134(3):60-64.
[79]Schmitt CS, Halbur PG, Roth JA, et al. Influence of ampicillin, ceftiofur, attenuated live PRRSV vaccine, and reduced dose Streptococcus suis exposure on disease associated with PRRSV and S. suis coinfection[J]. Veterinary Microbiology,2001,78(1):29-37.
[80]Feng Wen-hai, Laster SM, Tompkins M, et al. In Utero Infection by Porcine Reproductive and Respiratory Syndrome Virus Is Sufficient To Increase Susceptibility of Piglets to Challenge by Streptococcus suis Type II [J]. The Journal of Virology,2001,75(10): 4889-4895.
[81]Berthelot-Herault, Florence, Gottschalk, Marcelo, Labbe, Annie, et al. Experimental airborne transmission of Streptococcus suis capsular type 2 in pigs[J]. Veterinary Microbiology,2001,82(1):69-80.
[82]Williams AE, Blakemore WF, Alexander TJ. A murine model of Streptococcus suis type 2 meningitis in the pig[J]. Res Vet Sci,1988,45(3):394-9.
[83]Kataoka Y, Haritani M, Mori M, Kishima M, Sugimoto C, Nakazawa M, Yamamoto K. Experimental infections of mice and pigs with Streptococcus suis type 2[J]. J Vet Med Sci, 1991,53(6):1043-9.
[84]王继春,何孔旺,何家惠,等.2型猪链球菌动物致病性试验[J].中国兽医科技,2001,31(12)：23-25.
[85]Vecht U, Stockhofe-Zurwieden N, Tetenburg BJ, et al. Virulence of Streptococcus suis type 2 for mice and pigs appeared host-specific[J]. Veterinary Microbiology,1997,58(1):53-60.
[86]吴全忠,田云,等.猪链球菌2型引致及炎及败血症的豚鼠模型[J].中国兽医学报,2002,22(3)：228-230.
[87]陆承平,姚火春,范红结,等.猪链球菌致病性研究及其公共卫生意义[J].中国预防医学杂志,2006,7(4)：361-362.
[88]濮俊毅,黄新新,陆承平.用斑马鱼检测猪链球菌2型的致病力[J].中国农业科学,2007,40(11)：2655-2658.
[1]BraunS, Jechart G, Emmerling U, Ehret W. Streptococcus suis meningitis, a rare occupational disease[J]. Dtsch Med Wochenschr.2007,18; 132(20):1098-100.
[2]Tang J, Wang C, Feng Y, et al, A Glimpse of Streptococcal Toxic Shock Syndrome from Comparative Genomics of S. suis 2 Chinese Isolates[J]. PLoS ONE.2007,2:e315.
[3]李春,张东,李金海,等.四川省猪链球菌的分离与鉴定[J].四川畜牧兽医,2005,32(9)：25-26.
[4]朱虹,何君,荆红波,等.四川省资阳市爆发得猪链球菌感染疫情中病原菌得分离和鉴定[J].微生物学报,2006,46(4)：635-638.
[5]方绍兴,陆承平.猪链球菌2型江苏分离株溶血素基因的检测及序列分析[J].中国畜牧兽医,2006,33(3)：59-61.
[6]吴能简,黄祖星,陈抒豪,等.广东省首例家庭主妇感染猪链球菌的调查处理[J].中国人兽共患病学报,2006,22(8)：796.
[7]何孔旺,陆承平,倪艳秀,等.PCR方法检测2型猪链球菌2种毒力因子[J].扬州大学学报：农业与生命科学版,2002,23(3)：1-4.
[8]Jacob AA, Cloeffen P L W, Van Den Berg A J G, et al. Indentification of a thiol-activated hemolysin of Streptococcus suis[J]. Infect and Immune,1994,62:1742-1748.
[9]Nortonp M, Rolph C, Ward PN, et al. Epithelial invasion and cellysis by virulent st-rains of Streptococcus suis is enhanced by the presence of suilysin[J]. Immunol Med Microbiology,1999,26 (1):25-35.
[10]Baum CG, Das LM,Goethe R. Occurrence and diagnosticrelevance of virulence-associated factors in Streptococcus suis[J]. Dtsch Tierarztl Woehenschr,2003.110(9)378-381.
[11]Chen C, Tang J, Dong WA glimpse of streptococcal toxic shock syndrome from comparative genomics of S.suis 2 Chineseisolates[J].PLos One.2007, 2(3):315.
[12]Fittipaldi N,Gottschalk M,Vanier G, et al.Use of selective capture of transcribed sequences to identify genes preferentially expressed by Streptococcus suis upon interaction with porcine brain microvascular endothelial cells[J].Environ Microbiol.2007.73:4359-4364.
[13]顾宏伟,陆承平.猪链球菌2型新的感染相关因子自溶索的鉴定与分[J].微生物学报,2008,48(1)：68-72.
[14]Takamastu D. Osakj M. Tharaviehitkul P, et al. ABelie variation and prevalence of serum opacity factor among the Streptococcus suis population[J].J Med Microbiol,2008,57:488-494.
[1]黄毓茂,黄引贤,余志东,等.2型猪链球菌病的初步研究[J].中国畜禽传染病,1993,(5)：13.
[2]van der Sar A M, Appelmelk B J, Vandenbroucke-Grauls C M, et al. A star with stripes: zebrafish as an infection model[J]. Trends in Microbiology,2004,12(10):451-457.
[3]Kataoka Y, Haritani M, Mori M, et al. Experimental infections of mice and pigs with Streptococcus suis type 2[J]. J Vet Med Sci,1991,53(6):1043-1049.
[4]Beaudoin M, Higgins R, Harel J, et al. Studies on a murine model for evaluation of virulence of Streptococcus suis capsular type 2 isolates[J]. FEMS Microbiology Letters,1992, 99(2-3):111-116.
[5]Berthelot-Herault F, Cariolet R, Labbe A, et al. Experimental infection of specific pathogen free piglets with French strains of Streptococcus suis capsular type 2[J]. Can J Vet Res, 2001,65(3):196-200.
[6]崔立,朱建国,华修国,等.猪链球菌2型四川株与江苏株对SPF猪的致病性[J].上海交通大学学报：农业科学版,2006,24(1)：54-57.
[7]MADSEN L W, BAK H, NIELSEN B, et al. Bacterial Colonization and Invasion in Pigs Experimentally Exposed to Streptococcus suis Serotype 2 in Aerosol[J]. Journal of Veterinary Medicine Series B,2002,49(5):211-215.
[8]Vecht U, Stockhofe-Zurwieden N, Tetenburg B J, et al. Virulence of Streptococcus suis type 2 for mice and pigs appeared host-specific[J]. Veterinary Microbiology,1997,58(1):53-60.
[9]李业鹏,计融,韩春卉,等.建立小鼠免疫抑制低下模型的初步研究[J].中国食品卫生杂志,2001,13(6)：7-10.
[10]朱晓彤,江青艳,王丙云,等.环磷酞胺诱导黄羽肉鸡免疫抑制的研究[J].华南农业大学学报(自然科学版),2003,24(4)：60-63.
[11]Berthelot-Herault, Roland Cariolet, Annie Labbe et al. Experimental infection of specific pathogen free piglets with French strains of Streptococcus suis capsular type 2[J]. The CanadianJournal of Veterinary Research,2001,65:196-200.
[1]Chanter N, Jones PW, Alexander TJL. Meningitis in pigs caused by Streptococcus suis aspeculative review[J]. Vet.Microbiol,1993,36:39-55.
[2]Arends J P, Zanen H C. Meningitis caused by Streptococcus suis in humans[J]. Rev Infect Dis, 1988,10(1):131-137.
[3]Vecht U, Wisselink H J, Jellema M L, et al. Identification of two proteins associated withvirulence of the Streptococcus suis type 2[J]. Infect Immun,1992,59:3156-3162.
[4]Robertson I.D., Blackmore D.K. Experimental studies on the comparative infectivity an pathogenicity of streptococcus suis type 2,1 porcine and human isolates in pigs[J]. Epidemiol.Infect,1990,105:469-478.
[5]褚美芬,倪柏锋,孙琦,等.浙江省某猪场暴发Ⅱ型猪链球菌感染及病原诊断和药敏试验[J].微生物学杂志,2004,24(5)：126-128.