2型猪链球菌的毒力因子的鉴定及分布

为探讨河南省2型猪链球菌的毒力及分布情况,本实验设计3对引物,分别扩增溶菌酶释放蛋白(muramidase-released protein,MRP)、胞外因子(extracellular protein fateror,EPF)和溶血素(suilysin,SLY)基因,对2016年1月～2016年12月从河南省猪场采集的各种组织病料中分离鉴定出的87株2型猪链球菌进行了初步的小鼠毒力试验和mrp、epf、sly基因的扩增。结果表明,河南省流行的2型猪链球菌的菌株均对小鼠有毒力,共有8种毒力基因型,其中以毒力相对高的sly+mrp+epf+型为主,其次为sly+mrp-epf+型和sly-mrp+epf+型。     

通山县某猪场猪链球菌分离株毒力特征及耐药性研究

对通山县某猪场猪链球菌(Streptococcus suis,SS)病料进行了毒力特征及耐药性研究.结果获得血清1型1株,血清2型12株,血清7型2株,血清9型3株.PCR检测epf、mrp和sly,结果显示epf+/mrp+/sly+型有7株,epf-/mrp+/sly+型有5株,epf-/mrp-/sly-型有6株...     

猪链球菌的分离鉴定及毒力分析

通过对山西某猪场发病猪组织器官分离的病原菌鉴定以确定病原微生物以及其毒力强弱。主要从发病猪的关节液、肝脏、心脏、脾脏等器官内采集病原菌经过培养、镜检、生化试验初步鉴定后,用PCR方法通过扩增gdh基因和16SrDNA基因,16SrDNA测序后与国内外一些地区分离株的同源性比对,MLST(aroA、cpn60、dpr、gki、mutS、recA、thrA)分型研究、血清学分型以及mrp,ef,sly 3对毒力基因的扩增分析,结果鉴定为猪链球菌2型(SXZ-1株),16SrDNA序列与国内外部分地区菌株序列的同源性达到99%¹00%。MLST型为ST7型,具有强致病性(mrp+ef+sly+),表明山西存在ST7型强毒2型猪链球菌。     

猪链球菌2型湖南分离株4种毒力基因的序列分析

本试验对猪链球菌2型湖南分离株的cps2j、mrp、epf、sly四种毒力基因进行部分序列扩增、测序后分析,结果表明,4株2型猪链球菌均可检出这四种毒力基因,其中cps2j、epf、sly三基因与国内外报道其他分离株具有很高同源性(98%以上)。然而湖南分离株Hunan-An1、Hunan-An2、Hunan-Ping的mrp基因与其他对比菌株相比同源性低,进化关系远,有较大变异。     

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。     

猪链球菌2型安徽分离株毒力基因cps2J、mrp、epf、sly的检测及其序列分析

为了解19株猪链球菌2型(S.suis 2)安徽分离株的毒力基因型及毒力基因变异情况,通过PCR扩增S.suis 2毒力基因cps2J、mrp、epf和sly,对这4种毒力基因的扩增片段进行序列测定,并与国内外其他分离株的基因序列进行比较.结果显示,cps2J、mrp、epf和sly基因在19株S.suis 2中的检出率分别为100％、68.4％、68.4％、78.9％;19个受试菌株共分为7个毒力基因型,其中cps2J+/mrp+/epf+/sly+占57.9％,为优势基因型;S.suis 2安徽分离株4种毒力基因的检测序列之间及其与国内其他地区S.suis 2分离株的相应序列同源性均在99.1％以上,与国外S.suis 2分离株的相应序列同源性在87.8％～100％之间;19株cps2J+菌株中有1株菌cps2J基因序列有变异,13株mrp十菌株中有6株菌mrp基因序列发生变异,检测的epf和sly基因序列没有变异.表明cps2J +/mrp+ /epf+/sly+是S.suis 2安徽分离株优势毒力基因型,检测的S.suis 2安徽分离株cps2J、epf和sly基因部分序列较保守,mrp基因部分序列存在较大的变异.     

猪链球菌1型临床分离株的鉴定和基因组学分析

从罹患肺炎型猪链球菌病的仔猪气管中分离出1株猪链球菌强毒株,命名为SS2011GZ,经PCR鉴定为血清1型.斑马鱼攻毒试验测得该菌株的半数致死量(LD50)为4.09×104CFU/mL,有较强毒力;全基因组测序分析显示,毒力基因型为mrp+gdh+epf+sly+fbps-sao-,存在19个基因岛,24种耐药基因,...     

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。     

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.     

猪链球菌4型分离株生物学特性研究

为分析猪链球菌4型(Streptococcus suis type 4,SS4)分离株的病原生物学特性,试验对来自中国不同地区的10株猪链球菌4型进行了多位点序列分型,通过PCR方法对猪链球菌7个保守管家基因aroA、gki、dpr、mutS、recA、thrA、cpn60进行扩增,测序后将结果上传至MLST数据库查找序列型,然后制作聚类分析图来阐明菌株之间的亲缘关系;采用PCR方法对7种主要的毒力基因gdh、mrp、epf、sly、fbps、gapdh与orf2进行鉴定,通过毒力因子谱来分析猪链球菌4型毒力因子的分布;以纯化的10株细菌对BALB/c小鼠进行动物致病性试验,根据小鼠致死数量筛选出最强毒株,并进行新西兰兔致病性试验。结果显示,10株猪链球菌4型经多位点序列分型,6株为ST850型,3株为ST1006型,1株为ST94型;结合菌株分离地区分析发现,广东和江苏地区菌株有较高的同源性,江沪地区菌株出现分化现象,表现为遗传多样性;10株菌株均检测到了gdh、gapdh和orf2毒力基因,7株检测到sly基因,4株检测到fbps基因,根据毒力因子谱发现共有3个毒力基因型,gdh+sly+gapdh+orf2+型有6株,gdh+fbps+gapdh+orf2+型有3株,gdh+sly+fbps+gapdh+orf2+型仅有1株。动物致病性试验表明,10株细菌均能使BALB/c小鼠死亡,其中SH1510的半数致死量低至1×108 CFU,对小鼠的致病性最强,将纯化的SH1510菌液接种新西兰兔,可使新西兰兔出现典型的神经症状并死亡。以上结果为猪链球菌的遗传进化、毒力研究提供了新的数据,丰富了猪链球菌病的研究。     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Chemotaxis of macrophage in inflammation

Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein