急性死亡猪中猪丹毒杆菌的分离鉴定

本试验从江西省南昌市某规模化猪场送检的2份疑似猪丹毒杆菌引起的急性死亡猪组织中分离出2株可疑菌株,经细菌分离培养、染色镜检、生化试验等实验室诊断,进一步以猪丹毒杆菌16S rRNA的特异性引物进行PCR鉴定,确定2株分离菌为猪丹毒杆菌.然后进行动物致病性试验及药敏试验,并对该厂常用的消毒药进行最小抑菌浓度(MIC)的测定.结果表明,1×10⁸ CFU的剂量可致死小白鼠;分离菌对β-内酰胺类抗菌药高度敏感,对多数抗菌药耐药;该厂常用消毒药的抑菌作用已明显下降.本试验结果对临床防制猪丹毒具有参考意义.     

猪丹毒杆菌血清型鉴定及药敏特性研究

为确诊导致广西部分地区猪场发生生猪大量死亡的原因,采集病死猪心血、肝、脾等组织,经细菌分离、生理生化鉴定、致病性试验、16SrDNA序列分析、血清型鉴定等系统的鉴定与分析。结果表明,分离到12株猪丹毒杆菌,确定猪场发病的病原为猪丹毒杆菌,血清型为1a型。所有的分离菌株具有一致的形态特征和生理生化特性,致病性较强。按分离地区选择4株临床分离菌株与20世纪50至80年代分离的4株菌株同时进行药敏试验,结果发现:所有菌株对β-内酰胺类、氯霉素类、大环内酯类、硝基呋喃类和双萜类药物仍保持高敏,是治疗猪丹毒的首选药物;但对四环素、林可霉素、诺氟沙星敏感性出现差异,4株临床分离菌株对上述3种药物的敏感性显著低于4株老菌株,表现为一定的耐药。多数菌株对氨基糖苷类、多肽类、磺胺类、硝基咪唑类、利福霉素家族药物表现为耐药。MIC测定结果显示青霉素仍然是治疗猪丹毒的首选药物。     

1株猪丹毒杆菌的分离鉴定及药敏试验

无菌操作采集某规模养猪场疑似感染猪丹毒杆菌的病死猪肺脏等组织进行细菌分离,从中分离出一株病原菌,经细菌分离培养、形体特性及生化鉴定,确定为猪丹毒杆菌。通过药敏试验表明,该菌对阿莫西林、青霉素及头孢类药物高度敏感,为临床用药防治猪丹毒杆菌病提供科学根据。     

副猪嗜血杆菌与猪丹毒丝菌混合感染病原的分离鉴定及生物学特性分析

从疑似副猪嗜血杆菌和猪丹毒丝菌混合感染病猪无菌采集心脏、肝脏、脾脏、肺及心包积液,采用常规分离培养法分离病原菌,通过染色镜检、生化鉴定、卫星试验和核酸测序同源性比对,确诊为副猪嗜血杆菌与猪丹毒丝菌混合感染。为进一步了解2株菌的生物学特性,测定了2株菌以及混合菌液的半数致死量(LD50)以及对常用抗生素的药物敏感性。结果显示:(1)将2株菌的序列与GenBank数据库中已发表序列进行同源性比对,副猪嗜血杆菌与猪丹毒丝菌的同源性各达到96%和99%;(2)致病性试验中,SPF鼠均在接种后24h左右开始死亡,从其心脏、肝脏、脾脏及肺均回收到攻毒菌,表明2株菌均为此次疫病的主要致病菌;(3)通过测定副猪嗜血杆菌和猪丹毒丝菌的LD50分别为5.28×109、3.58×104 CFU/mL,进一步证明二者具有较强毒性。根据2株菌的LD50等体积混合2种菌液注射SPF鼠,副猪嗜血杆菌与猪丹毒丝菌LD50均出现下调,分别为3.70×109、2.51×104 CFU/mL,表明混合感染增强了二者的致病力;(4)药敏试验结果显示副猪嗜血杆菌与猪丹毒丝菌对常用抗生素的耐药性与临床耐药谱相一致,未出现新的耐受药物;同时筛选出了2种菌的共敏感药物氧氟沙星和氟苯尼考,有利于对疾病的快速治疗与防控。     

一株猪丹毒杆菌分离株的致病性与耐药性分析

从某猪场病死猪心血、肝、脾等组织分离到1株革兰阳性杆菌,经细菌形态、16S rRNA基因扩增,确定分离菌为猪丹毒杆菌。对分离菌进一步开展了药物敏感性试验、耐药基因的检测、细菌致病性试验及免疫保护性试验。结果发现:分离株对β-内酰胺类、大环内酯类、氟苯尼考高敏,但对氨基糖苷类、四环素、林可霉素、诺氟沙星等耐药;分离株可扩增出氨基糖苷类耐药基因aac C2和四环素耐药基因tetB,但菌株中没有扩增到四环素耐药基因tetA。细菌致病性试验表明该毒株对小鼠的LD50为1.77×10~5cfu/mL。小鼠免疫保护试验结果表明,疫苗G4T10免疫后28 d,以分离株攻毒,对照组全部死亡(5/5),免疫组小鼠攻毒后没有死亡,仅表现为体重减轻,表明现用猪丹毒疫苗能保护小鼠抵抗猪丹毒的致死性攻击。     

一株猪丹毒杆菌的分离鉴定及spaA基因序列分析

从猪丹毒疑似病例肺脏中分离到1株革兰阳性小杆菌,编号为YN19071,对其进行形态学、分子生物学鉴定,并研究其致病性、耐药性以及spaA基因遗传进化关系。16S rRNA基因序列在NCBI数据库中进行BLAST比对,结果显示分离株YN19071与猪丹毒杆菌(Erysipelothrix rhusiopathiae)模式菌株ATCC 19414~T同源性99.9%,对小鼠有较强的致病性。spaA基因进化分析显示,YN19071与10株猪丹毒杆菌中国分离株之间的同源性为98.8%～99.5%,与疫苗株G4T10同源性为99.3%。与疫苗株G4T10相比较,云南分离株YN19071的spaA基因存在3个突变位点T609G、A635G和A671G,对应的氨基酸序列也存在3个突变位点I203M、E212G和E224G。本研究在首次对云南猪丹毒杆菌spaA基因遗传进化分析,对云南猪丹毒杆菌的疫苗免疫防控具有指导意义。     

猪丹毒杆菌分离鉴定及体外抑菌试验

为了确诊临床疑似猪丹毒病例,采集病死猪的内脏,用常规生化法和PCR法进行细菌分离鉴定,用牛津杯法做体外抑菌试验。结果:分离菌H_2S、靛基质、枸橼酸盐等试验为阴性;分解葡萄糖、麦芽糖等,不能分解蔗糖;对青霉素、头孢唑啉等高度敏感,对氯霉素、链霉素等中度敏感;枯草芽孢杆菌、鸡唾液乳酸杆菌和猪小肠乳酸杆菌对其均有较强的抑制作用。结论:分离菌为猪丹毒杆菌,该病是由猪丹毒杆菌引起的急性热性传染病,防治首选药物为青霉素,枯草芽孢杆菌、鸡唾液乳酸杆菌和猪小肠乳酸杆菌可减少或部分取代抗生素对该病的防治。     

种鸭源猪丹毒丝菌分离及血清学调查

从发生生产性能异常的2个种鸭群中分离到2株革兰阳性丝状菌,经16S rRNA基因序列分析鉴定为猪丹毒丝菌。采用多重PCR对分离株编码表面保护性抗原(spa)基因进行扩增,分别获得大小约1 000 bp和900 bp的片段,判定为spaC型和spaB型。毒力检测结果表明,2个分离株对小鼠的半数致死量(LD50)分别为103CFU/0.2 mL和≤102CFU/0.2 mL。药敏试验结果表明,分离株对青霉素类和大部分头孢菌素类抗生素敏感,对氨基糖苷类等药物具有明显的抗性。为进一步了解猪丹毒丝菌对鸭群的感染情况,本研究采用生长凝集试验对来源于3个不同鸭场的种鸭群进行血清学调查,结果,抗丹毒丝菌抗体阳性率(抗体效价≥16)分别为82%、35%和20%,表明鸭群中广泛存在猪丹毒丝菌感染。     

一株母猪猪丹毒杆菌的分离鉴定及药敏试验

笔者从江西省吉安市某规模化猪场急性死亡的母猪体内分离到1株革兰氏阳性丝状杆菌,通过革兰氏染色、生化鉴定、培养特性观察及PCR鉴定,确定该病原菌为猪丹毒杆菌。药敏试验结果表明,分离菌株对头孢类抗生素、青霉素、阿莫西林等高度敏感。综合该场流行病学、临床症状和细菌分离鉴定结果,确诊该场母猪急性死亡原因是由急性猪丹毒杆菌感染所致。     

猪丹毒丝菌不同年代分离菌株流行病学特征及部分生物学特性比较研究

比较新近分离到的4株猪丹毒丝菌与4株20世纪50—80年代猪丹毒丝菌参考菌株的流行病学特征及部分生物学特性。观察菌株的生长形态特征,绘制生长曲线,测定生理生化特性、药物敏感特性、半数致死量(LD50)及疫苗免疫保护作用,同时用PCR方法扩增8株猪丹毒丝菌4个毒力因子的7个毒力基因片段,并以GXBY-1代表株进行毒力基因的遗传进化分析。结果显示,8株菌表现出一致的形态特征、生长曲线和生理生化特性;LD50结果显示,新近分离到的4株菌LD50高于4株参考菌株,表明新近分离菌株毒力有所下降;免疫保护试验结果表明,免疫GC42株活疫苗的昆明小鼠在注射不同年代的猪丹毒丝菌后仍能保持80%~100%存活;对8株菌进行30种常用抗菌药物的药物敏感试验,结果显示,8株菌对β-内酰胺类、氯霉素类、大环内酯类、硝基呋喃类和双萜类药物仍保持高敏,但对四环素、林可霉素、诺氟沙星敏感性出现差异,4株新近临床分离菌株对上述3种药物的敏感性显著低于4株老菌株,表现为耐药。多数菌株对氨基糖苷类、多肽类、磺胺类、硝基咪唑类、利福霉素家族药物表现为耐药。8株菌均能扩增出7个毒力基因,与参考菌株相比新近临床分离菌株毒力基因中仅CPS A、CPS C发生变异,而SpaA、Sialidase、CPS B、RspA、RspB为保守基因,同源性近100%。结果表明,不同年代猪丹毒丝菌具有较为一致的生物学特性,但其中菌株LD50、药物敏感特性、毒力基因遗传性出现了差异。     

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.     

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.     

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.     

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.     

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     

Avian brood parasitism — a growing research area in behavioral ecology (part Ⅱ)

正We are pleased to publish the second special issue on avian brood parasitism and to be responsible guest editors for the two special issues of Chinese Birds (Vol. 3, No. 4, 2012 and Vol. 4, No. 1, 2013), entitled "Avian Brood Parasitism - A Growing Research Area in Behavioral Ecology". The first issue was published in December 2012. The goal of the two special issues is to publish accumulated knowledge and some of the recent developments in     

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

Tropical Animal Health and Production -