猪源停乳链球菌类马亚种的分离与鉴定

从江西省吉安市某规模化养猪场发病仔猪关节液中分离得到1株革兰阳性链球菌,对其进行菌落形态观察、生化鉴定以及16S rRNA序列分子测序鉴定,并构建系统发育树;对分离菌进行药敏试验和健康小鼠的人工感染试验。结果根据分离菌的形态特征、理化特性,结合16S rRNA序列测定与系统发育分析结果,判定为链球菌属的停乳链球菌类马亚种(Streptococcus dysgalactiae subsp.equisimilis),并命名为JXJASD-1株。抗生素药物敏感试验结果表明,分离菌株对阿莫西林、头孢拉定、利福平表现较高的敏感性,对强力霉素、青霉素G中度敏感,而对庆大霉素、卡那霉素、四环素、红霉素、复方新诺明、磺胺异噁唑表现出耐药性;致病性试验结果表明,分离菌株对小鼠有强致病性。本结果将对江西省仔猪停乳链球菌类马亚种病的防治提供指导。     

无乳链球菌及其血清型的PCR方法鉴定

无乳链球菌(S.agalactiae)是引起奶牛乳房炎和新生儿期侵袭性感染(包括败血症、肺炎和脑膜炎)的重要病原菌.为快速准确地鉴定S.agalactiae及其血清型,本研究对22株从国内不同地区分离的牛源链球菌进行生化鉴定以及针对S.agalactiae保守基因sip进行PCR鉴定,并采用多重PCR技术扩增sip基因阳性菌株的cps基因进行血清分型.结果显示,PCR扩增sip基因阳性17株,其中15株生化试验与PCR结果一致;多重PCR扩增cps基因显示,其中Ia型4株、Ⅱ型11株、Ⅲ型2株.本研究为鉴定S.agalactiae及其血清型提供了参考.     

广西罗非鱼主养区致病性链球菌及其耐药性调查

为了解致病性无乳链球菌在广西罗非鱼主养区的分布及其耐药性情况,对广西各地区发病罗非鱼进行现场采样,以常规方法从患病罗非鱼的脑、心脏和肝脏等组织分离细菌,人工回归感染试验确定分离菌株的致病性,以API 20 Strep和16S rRNA分别对菌株进行生化鉴定和分子鉴定,K-B药敏纸片扩散法检测菌株的耐药性。调查结果,从广西8个市12个县/区采集的672个罗非鱼病样中,有30个病样共检出致病性强的革兰氏阳性球菌30株,参考株总检出率4.46%,百色市和来宾市的病样中未分离到革兰氏阳性球菌;经鉴定,分离到的30株球菌均为无乳链球菌(Streptococcus agalactiae),与无乳链球菌(S.agalactiae)参考株JF423947、JQ039375、KF111315和JQ99015616SrRNA核苷酸的同源性最高(98.5%~100%);28种药物的药敏试验结果显示,对所有菌株敏感的药物只有盐酸沙拉沙星1种,对所有菌株耐药的药物有磺胺-6-甲氧嘧啶(钠)、磺胺对甲氧嘧啶和复方磺胺嘧啶3种。     

奶样中无乳链球菌和乳房链球菌的分离与鉴定

奶牛乳房炎是奶牛最常见的疾病之一.该病主要由细菌引起,在牛群中广泛存在,其中无乳链球菌(Streptococcus agalactiae)、停乳链球菌(Streptococcus dysgalactiae)和乳房链球菌(Streptococcus uberis)是奶牛乳房炎主要的致病性链球菌.试验采用THB(Todd-Hewitt Broth)固体选择性培养基和色素试验培养基快速分离无乳链球菌和乳房链球菌,并结合生物梅里埃开发的VITEK全自动细菌鉴定仪进行准确鉴定,从而建立一种从奶样中快速分离无乳链球菌和乳房链球菌的常规方法.     

牛源无乳链球菌的耐药率调查及其耐药机制研究进展

无乳链球菌(Streptococcus agalactiae,S.agalactiae)是奶牛乳房炎的主要致病菌之一,给奶牛养殖行业带来严重的经济损失。为了解国内外无乳链球菌耐药性的变迁规律并为奶牛场奶牛乳房炎治疗提供参考,笔者对国内外2009～2018年无乳链球菌的耐药率进行了分析,对无乳链球菌耐药机制的研究进展进行了扼要综述,以期为奶牛乳房炎临床合理用药及有效防治提供思路和依据。     

俄罗斯鲟源停乳链球菌停乳亚种分离、鉴定及药敏特性研究

2016年6月~8月,湖北鲟养殖场的俄罗斯鲟发生一种以上下嘴唇充血肿胀为特征的病害。为确定其发病原因,本研究对自然发病鱼的病灶及内脏器官进行了病原菌的分离,并对分离株进行人工感染、毒力检测、生理生化特性测定及16S r RNA基因序列分析。结果从患病俄罗斯鲟体内分离到一株优势菌,人工感染试验出现与自然发病类似症状,确定其为俄罗斯鲟本次发病的病原菌,其对俄罗斯鲟幼鱼的半数致死剂量为3.64×10~4 cfu/g,该分离株生理生化特性与停乳链球菌停乳亚种一致;经16S rRNA基因序列比对及构建系统发育树结果显示,该分离株与停乳链球菌停乳亚种聚为一支,同源性在99%以上。该分离株鉴定为停乳链球菌停乳亚种(Streptococcus dysgalactiae subsp.dysgalactiae),命名为HD03。药敏试验结果表明,HD03株对环丙沙星、痢特灵及氟苯尼考等8种抗生素敏感,对苯唑西林、头孢唑林及阿莫西林等7种抗生素耐药。本研究首次证实停乳链球菌停乳亚种是俄罗斯鲟的病原菌,养殖时可以选用氟苯尼考进行防控。     

甘肃省山丹地区马子宫内膜炎主要病原菌的分离鉴定及多重PCR检测方法的建立

旨在对甘肃省山丹地区马子宫内膜炎主要致病菌进行分离鉴定并建立一种病原菌多重PCR(multiplex polymerase chain reaction, MPCR)检测方法。根据病原菌分离鉴定结果,选取主要致病菌金黄色葡萄球菌(Saphylococcus aureus,S.aureus)、大肠杆菌(Escherichia coli,E.coli)和马链球菌(Streptococcus equi,S.equi)进行多重PCR检测方法的建立。提取3种标准菌株基因组并基于nuc、phoA、fneB的保守区域设计3对特异性引物,扩增预期核酸片段分别为1 319,385,109 bp,进行引物特异性MPCR验证同时对扩增条件中的退火温度、引物浓度优化,建立检测3种病原菌的多重PCR,完成样品检测评估。结果表明,山丹地区马子宫内膜炎主要致病菌为金黄色葡萄球菌、大肠杆菌和马链球菌,设计的引物与无乳链球菌(Streptococcus agalactiae,S.agalactiae)、肺炎链球菌(Pneumococcus)无交叉反应,建立的多重PCR检测方法退火温度在59.4℃时最佳;在引物为0.3～...     

浙江省主要奶牛养殖区奶牛隐性乳房炎病原菌调查

对浙江省四个主要奶牛养殖区金华、杭州、宁波以及台州的30个奶牛场中846头泌乳牛的3178个乳区进行了奶牛隐性乳房炎病原菌调查.首先用HMT乳房炎诊断试剂检查乳区奶样,采集HMT反应为阳性(++)和强阳性(+++)的乳区奶样进行细菌分离鉴定,对分离到的金黄色葡萄球菌(Staphylococcus aureus)进行药敏试验.结果表明,浙江省奶牛隐性乳房炎的头阳性率为54.3%,乳区阳性率为28.0%.主要病原菌的检出率依次为凝固酶阴性葡萄球菌(Coagulase negative staphylococci)34.0%、无乳链球菌(Streptococcus agalactiae)27.0%、金黄色葡萄球菌(Staphylococcus aureus)12.2%、停乳链球菌(Streptococcus dysgalactiae)13.0%、乳房链球菌(Streptococcus uberis)6.2%等.药敏试验结果表明,对青霉素、氨苄青霉素敏感的金黄色葡萄球菌分离株只有20.3%,对四环素和红霉素的敏感率也较低(34.8%和47.8%).多重耐药现象比较普遍,主要是对青霉素、氨苄青霉素、四环素、红霉素同时耐药.     

东北民猪源停乳链球菌的分离鉴定与药敏试验

为分离东北民猪源停乳链球菌(Streptococcus dysgalactiae)并鉴定其生物学特性,从齐齐哈尔市某东北民猪场死亡仔猪的肝脏及其关节液样品中分离病原菌,通过生理生化试验和分子生物学试验鉴定分离菌,研究了分离菌的致病性和药物敏感性。结果表明,分离到革兰阳性球菌1株,生化指标与停乳链球菌停乳亚种相符。系统进化树分析表明,分离菌株与停乳链球菌停乳亚种参考菌株的同源性为97%~98%,其中与AB537921.1(Japan)同源性最高,达到98.99%,进一步从分子水平鉴定该菌为停乳链球菌停乳亚种。以0.2mL/只(3.2×10^9CFU/mL)接种量感染小鼠,发病率和病死率均为100%。分离菌对多黏菌素B、阿莫西林、氨苄西林、环丙沙星、氧氟沙星、庆大霉素、氟苯尼考、林可霉素、新霉素均敏感,仅对罗红霉素耐药。     

东北民猪停乳链球菌停乳亚种的分离鉴定

为分离东北民猪停乳链球菌(Streptococcus dysgalactiae)并鉴定其生物学特性,从齐齐哈尔市某东北民猪场死亡仔猪的肝脏及其关节液样品中分离病原菌,通过生理生化试验和分子生物学方法鉴定分离菌,研究了分离菌的致病性和药物敏感性。结果表明,分离到革兰阳性球菌1株,生化指标与停乳链球菌停乳亚种相符。系统进化树分析表明,分离菌株与停乳链球菌停乳亚种参考菌株的同源性为97%～98%,其中与AB537921.1(Japan)同源性最高,达到98.99%,进一步从分子水平鉴定该菌为停乳链球菌停乳亚种。以0.2 mL/只(3.2×10~9 CFU/mL)接种量感染小鼠,发病率和死亡率均为100%。分离菌对多黏菌素B、阿莫西林、氨苄西林、环丙沙星、氧氟沙星、庆大霉素、氟苯尼考、林可霉素、新霉素均敏感,仅对罗红霉素耐药。研究结果为东北民猪停乳链球菌停乳亚种病的诊断与防治提供了依据。     

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.     

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