重庆屠宰场猪链球菌感染的调查

旨在调查2021年重庆地区屠宰场表观健康猪群中猪链球菌的血清型、耐药和毒力特征，为制定该地区猪链球菌病的防控策略提供参考。以2021年重庆地区屠宰场表观健康猪扁桃体样品为试验材料，分离猪链球菌并对菌株进行血清型分型、耐药基因检测、药敏试验、斑马鱼毒力试验，分析猪链球菌的流行特征。结果显示：2021年5—6月于重庆屠宰场共采集表观健康猪扁桃体154份，检出猪链球菌阳性样本80份(51.95%),从中分离到菌株87株；主要血清型分别为16型(16.09%,14/87)、9型(9.20%,8/87)、4型(8.05%,7/87),而血清2型检出率较低，占比4.60%(4/87)。分离株对林可酰胺类、四环素类、大环内酯类抗生素耐药率较高，分别为100%(87/87)、95.40%(83/87)、93.10%(81/87);对氨基糖苷类抗生素耐药率为59.77%(52/87);对利奈唑胺、β-内酰胺类、万古霉素、利福平的耐药率较低，分别为5.75%(5/87)、5.75%(5/87)、0(0/87)、0(0/87);96.55%(84株)的菌株对3类及以上的抗菌药耐药，属于多重耐药菌株。选取19...     

贵州省铜仁地区猪链球菌2型的分子流行病学分析

通过菌株分离培养、生化鉴定分析了贵州省铜仁地区各屠宰场收集的150份猪扁桃体样本,并用PCR方法对猪链球菌2型的主要致病毒力因子进行了检测。结果表明,150例样本中猪链球菌2型带菌率达到41.3%,其中屠宰场3的检出率较高,mrp、epf片段与阳性对照相关基因的同源性达到100%,屠宰场3的所有样本mrp、epf毒力因子均表现为阳性。说明该地区猪群猪链球菌2型携带率较高,mrp、epf毒性因子阳性表现型与疫病的流行可能存在一定的关联性。     

猪链球菌2型的鉴定及其毒力因子检测

猪链球菌的感染不仅对养猪业造成巨大的损失,同时对公共卫生尤其是相关从业人员的生命造成威胁,严重感染引起死亡.根据参考文献,设计了1对猪链球菌2型特异性引物.对四川分离的7株链球菌、江苏分离的1株、北京分离的6株和菌种中心保存的5株C群马链球菌兽疫亚种、1株D群链球菌、4株R型链球菌、2株S群链球菌和E、F、G、K、L、M、N、O、P群链球菌各1株进行了检测.结果7株四川分离株均为2型;1株江苏分离株为2型;6株北京分离株有3株为2型;1株R群、2株s群链球菌为2型猪链球菌.对检测出的14株猪链球菌2型的毒力因子做进一步检测.MRP基因检出率为92.9%(13/14);EF基因检出率为100%(14/14);sly基因检出率为71.4%(10/14);Cps2A基因检出率为92.9%(13/14);gapdh基因检出率为64.3%(9/14);FBPS基因检出率为92.9%(13/14);orf2基因检出率为71.4%(10/14).毒力因子全为阳性的菌株有6株,MRP-EF+菌株有2株.本研究从259份健康猪扁桃体中分离到16株2型猪链球菌,健康猪带菌率为6.2%(16/259).16株猪链球菌2型中,MRP、EF、Cps2A全为阴性,只从1株2型猪链球菌中检测到了sly基因(1/16);gapdh基因检出率为56.25%(9/16);FBPS基因检出率为75.0%(12/16);Orf2基因检出率为37.5%(6/16).     

上海屠宰样品中猪链球菌感染率调查研究

采集上海地区屠宰场中扁桃体样品,进行猪链球菌分离。按照染色特性及PCR鉴定阳性细菌。根据CPS基因采用PCR方法进行2、7及9血清型鉴定工作,并检测分离株毒力因子携带情况。结果证实在231份样品中共确定24份猪链球菌,其中2型10株、7型3株、9型2株,其余血清型待定。     

猪链球菌扁桃体分离株的毒力因子分布特征与致病性

本研究设计并合成7对引物,用PCR方法对猪链球菌7种主要毒力因子,包括谷氨酸脱氢酶(gdh)、溶血素(sly)、胞外蛋白因子(ef)、溶茵酶释放蛋白(mrp)、纤连蛋白/血纤蛋白原结合蛋白(fpbs)、三磷酸甘油醛脱氢酶(gadph)和毒力相关序列orf2进行检测,分析了29株猪链球菌扁桃体分离株的毒力因子分布特征.在被检的25株2型菌株中,共检测出7个基因型.其中10株(40%)的基因型为cps2/gdh+/sly+/ef+/mrp+/fbps+/gadph+/orf2+,7株(28%)表现为cps2/gdh+/sly-/ef-/mrp+/fbps+/gadph+/orf2+,4株(16%)表现为eps2/gdh+/sly-/ef+/mrp+/fbps+/gadph+/orl2+,基因型表现为eps2/gdh+/sly+/ef+/mrp+/fbps+/gadph+/orf2-、cps2/gdh+/sly-/ef-/mrp+/fbps+/gadph+/orf2-、eps2/gdh+/sly-/ef-/mrp*/fbps+/gadph+/orf2+、eps2/gdh+/sly-/ef-/mrp-/fbps-/gadph+/orf2-各1株;1株猪链球菌7型(SS7)分离株,基因型表现为cps7/gdh+/sly+/ef-/mrp-/fbps+/gadph+/orf2+;3株猪链球茵9型(SS9)扁桃体分离株,均表现为cps9/gdh+/sly-/ef-/mrp-/fbps+/gadph+/orf2+.可见我国SS分离株的毒力基因分布较为复杂,而且SS2的优势流行菌株是同时具有多种毒力因子的高致病茵株.通过对不同毒力基因型毒株对西藏小型猪的感染试验发现:毒力基因型为cps2/gdh+/sly-/ef+/mrp+/fbps+/gadph+/orf2+的健康扁桃体分离株SH06-21D对西藏小型猪有较强的致病性,仅次于标准株HA9801,而基因型为sly-/ef-/mrp-/fbps-/gadph+/orf2-的健康扁桃体分离株GZ06-122B对西藏小型猪不表现明显的致病性.     

屠宰场猪链球菌分离菌株分型及其致病性和耐药性分析

为了解吉林省猪链球菌的流行情况,从屠宰场采集的猪咽拭子和鼻拭子样品中分离鉴定猪链球菌,并进行菌株血清型、基因型和毒力表型的鉴定,以及致病性和耐药性的分析。结果表明,从100份样品中共分离鉴定猪链球菌104株,其中29株鉴定为血清2型、9型和1型等几种常见的致病性血清型,其他75株不属于常见的致病性血清型。血清2型的菌株中,2株经鉴定为ST1基因型和mrp+epf+sly+毒力型,并经动物试验鉴定为强毒菌株;其他菌株均为ST28基因型和mrp+epf-sly-毒力型,具有中等毒力。血清9型的菌株,均为mrp-epf-sly-毒力型,动物试验鉴定均为强毒菌株。根据Kirby-Bauer纸片扩散法的药敏试验结果,98%的猪链球菌分离株对四环素耐药;对大环内酯类、克林霉素和链霉素的耐药率都在50%以上;对β-内酰胺类、氯霉素和喹诺酮类抗生素的耐药率小于20%。总体分析,从屠宰场分离的猪链球菌强毒菌株所占的比例并不高,但是菌株多重耐药的情况非常严重。     

广东地区健康猪群和发病猪群猪链球菌流行病学调查分析

为了解广东地区猪群中猪链球菌（Streptococcus suis,SS）的流行情况,本研究对在广东地区养殖场采集的228份发病猪群样品及698份健康猪群样品（包括455份鼻拭子样品及243份屠宰场扁桃体样品）进行了SS携带情况的统计分析。结果显示,发病猪群SS的阳性率为82.02%（187/228）,健康猪群的SS阳性率为42.20%（192/455）,其中屠宰场屠宰猪群的SS阳性率为32.10%（78/243）。将从发病猪群分离到的187株SS及健康猪群（含养猪场和屠宰场）分离得到的154株SS进行血清型定型分析,结果显示,发病猪群共检测到11个血清型,包括SS1、SS2、SS3、SS4、SS7、SS8、SS9、SS16、SS19、SS29和SS31型,主要以SS2、SS3和SS19型为主,分别占16.58%、9.63%和7.49%;其次为SS7型（6.95%）和SS9型（5.34%）,未定型菌株占48.66%;健康猪群共检测到17个血清型,包括SS2、SS3、SS4、SS5、SS7、SS8、SS9、SS10、SS12、SS15、SS16、SS17、SS19、SS21、SS23、SS29和SS30型,主要以血清型SS2和SS29型为主,分别占18.83%和14.94%,其次为SS16型（6.50%）,未定型菌株占31.82%。     

河池市屠宰猪群中猪链球菌2型的流行病学调查

从我市4个县区的屠宰场采集屠宰猪扁桃体426份,其中东兰195份、宜州78份、环江35份、巴马118份.采用多重PCR方法检测样品中猪链球菌2型的流行病学情况.检出240份(56.34%)样品猪链球菌(SS)阳性,其中7份(1.64%)携带猪链球菌2型(SS2).表明河池市屠宰猪群中广泛存在猪链球菌,但猪链球菌2型带菌率较低.     

猪链球菌2型毒力因子与MLST分型分析

为了解我国猪链球菌2型毒力因子和MLST型的特点,对四川、重庆和山东等地的22株猪链球菌2型进行毒力因子检测和ST型分析。结果显示,78%(17/22)的分离株为sly+mrp+epf+基因型的强毒株,仅山东省的5株分离株为弱毒力型。四川省和重庆市89%(15/17)的分离株为毒力较强的ST7型,而山东省的分离株均为毒力稍弱的ST1型。结合这些地区的猪链球菌病发病情况,分析提示猪链球菌2型的毒力因子和ST分型与菌株的致病性有一定的相关性。     

广西部分地区猪群中猪链球菌分离株的毒力基因检测及毒力测定

为了解广西部分地区(玉林市、大新县、那坡县、东兴市、靖西市和百色市)猪群中猪链球菌(Streptococcus suis,SS)毒力基因的流行情况和毒力水平,试验采用PCR方法检测分离到的201株(经鉴定猪链球菌2&1/2型24株,猪链球菌7型2株,猪链球菌9型15株,一共41株)猪链球菌的毒力基因orf2、sly、ef和mrp,并通过斑马鱼模型筛选毒力较强的菌株,测定菌株的半数致死剂量(LD₅₀)。结果表明：从广西部分地区分离的201株猪链球菌的4种毒力基因携带率从高到低依次为orf2(85.6%,172/201)>sly(55.2%,111/201)>ef(33.8%,68/201)>mrp(26.4%,53/201);6个市县主要流行的毒力基因不同,玉林市、大新县、那坡县、东兴市、靖西市和百色市分离的猪链球菌携带最多的毒力基因分别为orf2(100%)、orf2(89.2%)、orf2(91.5%)、ef(44.4%)、orf2(86.7%)、orf2(40.0%);经鉴定分型的41株猪链球菌中,有7株(17.1%,7/41)同时携...     

南疆地区猪链球菌流行病学调查

为了解猪链球菌在新疆南疆地区正常猪群中的流行情况,对库尔勒地区、阿克苏地区、喀什地区无菌采集的286头份健康屠宰猪的扁桃体进行猪链球菌种的鉴定;采用猪链球菌谷氨酸脱氢酶（gdh）基因设计引物,建立PCR方法。结果表明,南疆地区猪链球菌的携带率达到了17．13％;对携带猪链球菌的扁桃体进行细菌的分离鉴定,荻得47株猪源性链球菌;采用多重PCR对分离的47株猪链球菌进行主要致病血清学的检测,未见主要致病血清型。     

Prevalence of the suilysin gene in Streptococcus suis strains isolated from diseased and healthy carrier pigs

Knowledge of virulence factors of Streptococcus suis is limited. Several virulence factor candidates have been proposed, among them suilysin, which is responsible for a toxic effect on epithelial cells. The aim of this study was to detect the suilysin gene sequence in Streptococcus suis strains of various origin. In total 63 Streptococcus suis isolates were investigated. Forty four of them originated from tissues of streptococcosis affected animals. The remaining 19 strains were isolated from tonsils of healthy carrier pigs. Suilysin gene specific sequence was detected in 79% of the strains tested. In isolates obtained from pigs with signs of streptococcosis this gene sequence was recorded in 85% of cases. In Streptococcus suis strains isolated from healthy carrier pigs the suilysin gene was detected in 63% of the isolates. It seems that suilysin toxic activity is only one of the many steps involved in the pathogenesis of Streptococcus suis infection and that strain's virulence cannot be stated only on the basis of suilysin gene sequence presence.     

猪链球菌2型两代表性分离株感染小型猪后对部分免疫指标的影响

为探讨致病性猪链球菌2型（SS2）感染后对猪外周免疫系统的影响,作者选用SS2两代表性分离株（即四川分离株ZY05719和江苏分离株HA9801）建立具有典型症状和病理组织特征的小型猪感染模型,分析感染后不同时间猪血液中细菌含量和白细胞变化,以及相关免疫指标的变化。结果表明,猪链球菌2型感染会引起小型猪的急性死亡、亚急性感染和慢性迁延。急性死亡猪的血液中细菌含量高达10^4CFU／mL。感染后的12h即可见IL-1、IL-8、TNF—α、IFN-γ分泌量显著增加,其中以TNF—α增幅最显著。同时可见CD4＋T细胞的水平明显下降,CD8＋T细胞的水平上升,急性死亡猪出现CD4＋／CD8＋T细胞比值倒置,即感染猪处于免疫抑制状态。急性死亡猪血液中的淋巴细胞转化能力变化无规律,亚急性感染猪的淋转指数在下降1周后逐渐恢复。结果提示：ZY05719和HA9801菌株的致病性有差异;外周血中各相关免疫指标和SS2感染进程有-定相关性。     

Streptococcus suis serotypes associated with disease in weaned pigs

Streptococcus suis was recovered from 9 outbreaks of septicaemia and meningitis in weaned pigs between 1979 and 1983. Fifteen isolates from 7 outbreaks were identified as S. suis type 9, and 3 isolates from 2 outbreaks as S. suis type 2. Three further isolates of S. suis type 2 and an isolate of S. suis type 3 were recovered from cases of bronchopneumonia in weaned pigs from 4 other piggeries.     

2型猪链球菌病

猪链球菌能引起猪脑膜炎、心内膜炎、关节炎、肺炎和败血症等,并可以感染人,是一种重要的人畜共患病病原。该菌有35个血清型,其中2型流行最广、致病性最强。本文就2型猪链球菌病的病原、流行病学、致病机理、检测技术及免疫预防等各方面情况作一综述。     

Pathogenesis of porcine reproductive and respiratory syndrome virus-induced increase in susceptibility to Streptococcus suis infection

Eighty 3-week-old crossbred pigs were randomly assigned to six groups (13-14 pigs/group). Group 1 pigs served as uninoculated controls, group 2 pigs were inoculated intranasally (i.n.) with Streptococcus suis serotype 2, group 3 pigs were inoculated i.n. with a modified live porcine reproductive and respiratory syndrome virus (PRRSV) vaccine, group 4 pigs were inoculated i.n. with the same vaccine and with S. suis, group 5 pigs were inoculated i.n. with VR-2385 (a high-virulence strain of PRRSV), and group 6 pigs were inoculated i.n. with VR-2385 and S. suis. Pigs exposed to both PRRSV and S. suis were inoculated with PRRSV 7 days prior to S. suis inoculation. The pigs were 26 days old when inoculated with S. suis. Respiratory disease was significantly more severe in groups 5 and 6. Mortality rate was the highest in group 6 (87.5%). This rate was significantly higher than that observed in all other groups except group 4 (37.5%). The mortality rate in group 2, inoculated with S. suis alone, was 14.3%. No pigs from groups 1, 3, or 5 died prior to the scheduled necropsies at 10 and 28 days postinoculation with PRRSV (DPI). To study the effect of PRRSV and/or S. suis on pulmonary clearance by pulmonary intravascular macrophages, six pigs from each group were intravenously infused with 3% copper phthalocyanine tetrasulfonic acid in saline prior to necropsy at 10 DPI. Mean copper levels in the lungs of pigs in groups 2, 5, and 6 were significantly lower than those in control pigs. The mean percentage of lung tissue grossly affected by pneumonia at 10 DPI was 0%, 1%, 0%, 3%, 64%, and 62% for groups 1-6, respectively. Both gross and microscopic interstitial pneumonia lesions were significantly more severe in the VR2385-inoculated groups (5 and 6). PRRSV was isolated from bronchoalveolar lavage fluid collected at necropsy from 100% of the pigs in groups 5 and 6, 71.4% of pigs in group 4, 38.5% of pigs in group 3, and none of the pigs in groups 1 or 2. Streptococcus suis serotype 2 was cultured from the internal tissues of 7.7%, 28.6%, and 78.6% of the pigs in groups 2, 4, and 6, respectively. Streptococcus suis serotype 2 was isolated from whole blood at necropsy from 7.7%, 35.7%, and 78.6% of pigs in groups 2, 4, and 6, respectively. Significantly more pigs in group 6 had S. suis isolated from whole blood and internal tissues. In summary, both high-virulence PRRSV and S. suis decreased copper clearance, and the incidence of isolation of S. suis and PRRSV was higher in dually inoculated pigs. PRRSV-induced suppression of pulmonary intravascular macrophage function may in part explain PRRSV-associated increased susceptibility to S. suis infection.     

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.     

湖南省猪链球菌的分离与鉴定

从病猪脏器病料中通过细菌培养、生化试验分离鉴定出了121株猪链球菌.经PCR技术鉴定马链球菌兽疫亚种28株,占23.1%,猪链球菌24株,占19.8% ,其中猪链球菌2型4株,占3.3%,猪链球菌9型2株,占1.7%,猪链球菌1型和7型都没检测到,证实省内除了猪链球菌2型外,也存在其他血清型的猪链球菌.     

Passive immunization of pigs against experimental infection with Streptococcus suis serotype 2

The safety and protective efficacy of a horse antiserum raised against inactivated whole cell preparations of Streptococcus suis serotype 2 was investigated in pigs by experimental challenge. The antiserum was evaluated in two similar experiments each comprising 12 4-week-old pigs treated with 6 ml of antiserum the day before challenge and four pigs used as challenge controls. Pigs were infected by subcutaneous injection with approximately 10(11) colony forming units of S. suis serotype 2. Clinical disease in the pigs that could be attributed to infection with S. suis was reduced from 88 to 35% (P = 0.015). The percentage of pigs with lesions that could be associated with S. suis was reduced from 88 to 22% (P = 0.002) and isolation of S. suis serotype 2 was reduced from five (63%) out of eight pigs in the combined challenge control groups to 3 (13%) out of 23 pigs in the combined treatment groups. These results indicate that passive immunization of pigs may be a way to reduce or control S. suis serotype 2 infections in pigs.     

Prevalence of Streptococcus suis types 1 and 2 in domestic pigs in Australia and New Zealand

Using an indirect fluorescent antibody test, 54 per cent of 734 palatine tonsils of conventional pigs slaughtered in Australia and New Zealand were found to be infected with Streptococcus suis type 1 and 73 per cent of 959 were infected with S suis type 2. Variations in the prevalence of infection in pigs from different herds were thought to be due to differences in the sample sizes rather than to real differences in the prevalence between herds. The prevalence of infection with S suis was similar in pigs of either sex and in different age groups. Streptococcus suis type 2 was detected in the blood of 3 per cent of apparently normal pigs slaughtered at a meat processing plant. The presence of this organism in edible tissue may pose a health risk to consumers and meat-workers. Both S suis types 1 and 2 were detected in the vaginas and uteri of slaughtered pigs and the female reproductive tract could be another site for the carriage of infection. Piglets from sows with vaginas infected with S suis type 2 became infected earlier than piglets from sows with uninfected vaginas. No infected male reproductive tracts were detected and venereal transmission of S suis therefore appears unlikely. Three specific pathogen free herds were found to be free from infection with both S suis types 1 and 2. It is concluded that hysterectomy derived piglets are delivered free from infection, whereas some piglets born to sows with uterine and vaginal infections are either born infected or become infected at, or soon after, birth.