河北部分地区狐狸源肺炎克雷伯菌血清型鉴定、毒力基因及致病性检测

为分析河北部分地区狐狸源肺炎克雷伯菌(Klebsiella pneumoniae)的荚膜血清型、毒力基因流行情况及致病性,从河北地区养殖场中采集患病狐狸肺脏、心血、肝脏等病料组织217份,分离得到63株致病性肺炎克雷伯菌。采用PCR法分别检测63株肺炎克雷伯菌荚膜血清型及19种毒力基因;通过人工感染小鼠致病试验验证4株优势血清型流行株的半数致死量(LD_(50))。结果显示,63株肺炎克雷伯菌中23株为K2血清型,7株为K20血清型。63株肺炎克雷伯菌携带13种毒力基因,毒力基因fimH、mrkD、wabG、uge、ybt、ybtA、alls、ompK35等检出率均在58.73%以上,其他毒力基因检测率较低;分离菌株呈现多重毒力基因型,同时携带9种毒力基因的菌株最多,占致病性菌株的33.33%。优势血清型流行株KD1(K20)和KD45(K2)的致病性最强,其LD_(50)分别为3.16×10~5,3.16×10~6 CFU/mL。本研究为该地区肺炎克雷伯菌病的防控提供参考。     

鲤鱼肺炎克雷伯氏菌分离与鉴定

初步了解肺炎克雷伯氏菌在鲤鱼鱼体中的发病机制并筛选防治药物,为预防和治疗该病提供准确实验数据。对发病鲤鱼进行细菌分离纯化,通过革兰氏染色反应,生理生化反应测定单菌落特性,进行细菌回归试验和药敏试验。对注射菌液后发病的鱼进行细菌再分离,得到革兰氏阴性菌,并且与七叶苷及其它17种指标反应呈阳性,与戊二酰-甘氨酸-精氨酸-AMC及其它11种指标反应呈阴性,注射该菌液48 h后鱼体出现与疑似病例相同病症。分离得到的细菌,按《伯杰氏细菌鉴定手册》进行鉴定,确定为肺炎克雷伯氏菌。药敏试验结果表明该菌对亚胺培南等6种药物高度敏感。本试验首次从鲤鱼体内分离出肺炎克雷伯氏菌,并得到6种高度敏感的药物,同时阐明了肺炎克雷伯氏菌在鲤鱼中发病症状。     

猪源肺炎克雷伯氏菌耐药性及毒力基因分析

为了解猪群中猪源肺炎克雷伯氏菌耐药情况和毒力基因携带状况,2019年采集存栏生猪肛拭子样品125份、宰后生猪肉类样品50份,通过细菌分离培养、药敏试验以及PCR扩增16S rRNA、khe基因、耐药基因和毒力基因等方法对肺炎克雷伯氏菌特性进行分析。结果显示,从125份肛棉拭子样品、50份宰后生猪肉类样品中各分离得到32、4株肺炎克雷伯氏菌;药敏试验结果显示,分离的肺炎克雷伯氏菌对四环素耐药性最高(83.3%),其次是氯霉素(63.9%)。对36株分离菌进行耐药基因和毒力基因检测,发现携带耐药基因tet(A)的达30株、携带floR、mcr-1的分别为23、10株,且有23株菌同时携带tet(A)和floR基因,少部份菌株携带aadA1、blaTEM、blaCTX-M-1、blaOXA、qnrB、aac(6')-Ib-cr;携带毒力基因wabG的达26株、携带uge和fimH的25株、携带kfu的23株、携带aereobactin的7株,且有20株菌同时携带wabG、uge、fimH和kfu基因。结果表明,我国猪群中肺炎克雷伯氏菌检出率可能较高,菌株携带耐药基因及毒力基因较为集中,对部分抗生素耐药性较强。本研究为肺炎克雷伯氏菌的检测、诊断以及合理使用抗生素治疗提供了试验依据,同时也为猪源肺炎克雷伯氏菌防控提供了数据支撑。     

肺炎克雷伯氏菌强毒株的分离鉴定及16-23SrRNAITS序列分析

为确诊疑似仔猪肺炎克雷伯氏菌(K.pneumonia)感染,并研究其病原的致病性、耐药性、16-23SrRNA ITS系统进化特征,本研究从云南因肺炎、腹泻而大量死亡的仔猪中分离到1株革兰氏阴性短粗杆菌,命名为KP14013,对其进行生化鉴定、16SrRNA鉴定,研究其对小白鼠和仔猪的致病性,并对其16-23SrRNA ITS基因进行测序和遗传进化分析。结果显示,KP14013分离株生化特征与肺炎克雷伯氏菌相符,其16SrRNA与GenBank中23株肺炎克雷伯氏菌代表株之间的同源性均为99%,将KP14013鉴定为肺炎克雷伯氏菌。KP14013对小白鼠半数致死量(LD50)为3×101.8 CFU,腹腔注射3×108 CFU可使仔猪100%致死。16-23SrRNA ITS系统进化关系结果表明,KP14013与GenBank中收录的15株肺炎克雷伯氏菌形成进化树的一个分支,属于同一个亚群,它们之间的核苷酸同源性为98.4%~99.2%。本研究证实了肺炎克雷伯氏菌是该起仔猪腹泻大量死亡的病原;KP14013分离株为毒力极强菌株,具有多重耐药性,其16-23SrRNA ITS与GenBank中收录的肺炎克雷伯氏菌代表株之间核苷酸存在差异,可用于肺炎克雷伯氏菌菌株间的鉴别。     

蒲公英内生真菌对2种鱼类病原菌抑菌效果研究

试验旨在研究蒲公英内生菌对由嗜水气单胞菌和迟缓爱德华氏菌引起鱼类疾病的作用效果,分为2部分:体外抑菌试验和攻毒试验.试验所用的嗜水气单胞菌菌液质量浓度为890万CFU/mL,迟缓爱德华氏菌菌液质量浓度为780万CFU/mL.体外抑菌试验结果显示,蒲公英内生菌对体外培养的2种细菌均有显著抑制效果,嗜水气单胞菌的抑菌圈直径为24.50 mm,对迟缓爱德华氏菌的抑菌圈直径为30.53 mm.攻毒试验以黄河鲤鱼为试验鱼,注射量为0.2 mL/尾.攻毒试验设5个处理组,即对照组、注射嗜水气单胞菌攻毒组、嗜水气单胞菌攻毒后投喂蒲公英内生菌饲料组、迟缓爱德华氏菌攻毒组和迟缓爱德华氏菌攻毒后投喂蒲公英内生菌饲料组.攻毒试验显示,迟缓爱德华氏菌攻毒后投喂含有蒲公英内生菌饲料组累积病死率显著高于未注射致病菌的对照组,低于注射致病菌投喂普通饲料的试验组.嗜水气单胞菌攻毒组与嗜水气单胞菌攻毒后投喂蒲公英内生菌饲料组试验鱼累计病死率无显著性差异.     

中药组方对鸡传染性支气管炎的防治效果

为探讨中药组方"传支散"对鸡传染性支气管炎的预防和治疗作用,本试验将200只17日龄三黄肉鸡随机分为5组,其中3个预防用药攻毒组Ⅰa、Ⅱa和Ⅲa,分别按每日每只0.5、1.0、1.5 g的剂量在饲料中添加"传支散",另两组分别为攻毒对照组和空白对照组,3 d后用复壮的鸡IBV标准株M41E4对Ⅰa、Ⅱa、Ⅲa及攻毒对照组鸡只攻毒。结果显示,1.0 g和1.5 g剂量预防效果很好,保护率达92.5%和95%;按每日每只鸡用1.0、1.5、2.0 g的剂量分别对3个自然感染IB蛋鸡组治疗,2.0 g治疗剂量组治愈率为88%。"传支散"对预防和治疗鸡传染性支气管炎有显著效果。     

新型药物饲料添加剂喹烯酮的一般毒性研究——Ⅰ.急性毒性试验

按简化寇氏(karber)法作喹烯酮口服急性毒性试验。对大白鼠的 LD_(50)为8178.996mg/kg,95%可信限为7473.086～8298.508mg/kg;对小白鼠的 LD_(50)为14397.928mg/kg,95%可信限为13372.112～15502.438mg/kg。     

河南驻马店地区猪源肺炎克雷伯氏菌分离菌株生物学特性

为了分析驻马店地区猪源肺炎克雷伯氏菌分离菌株生物学特性,从驻马店地区不同养殖场中采集患呼吸道疾病猪肺脏、鼻拭子等病料组织74份中分离得到了43株肺炎克雷伯氏菌。采用人工感染小鼠致病性试验、PCR方法和K-B药敏纸片分别检测49株肺炎克雷伯氏菌的致病性、血清型及耐药性。结果显示,30株肺炎克雷伯氏菌对小鼠具有很强的致病性;43株分离菌株以K5、K20为主要流行血清型,分别占分离菌株的37.2%、27.9%;43株分离菌株对氨苄西林、阿莫西林、大观霉素等7种药物耐药性较高,耐药率在51.2%以上,对其他药物的耐药率在18.6%~234.9%之间,且呈现多重耐药性,耐10、9种药物分离菌株最多,分别占分离菌株的25.6%、27.9%。本试验为该地区猪源肺炎克雷伯氏菌病的防治提供理论基础。     

一例牛肺炎克雷伯氏菌和大肠杆菌混合感染的诊断报告

近年来,随着牛养殖规模的增加,混合感染引发的疾病较严重。广西某牛场送来一例奶牛急性死亡病例,通过临床观察、细菌分离鉴定、病原鉴定、致病性试验和药敏试验的方法进行诊断。检测结果发现,内脏有明显的病理变化,从腹股沟淋巴结和脾脏分别分离出两种菌,经测序鉴定为肺炎克雷伯氏菌和大肠杆菌,且对小白鼠的致死率分别为80%和100%。17种药物的药敏结果显示这两种菌只对阿米卡星、大观霉素等少数几种抗菌药物敏感。PCR或RT-PCR未检测出IBRV、BPIV3、牛支原体。结论确诊该病例为肺炎克雷伯氏菌和大肠杆菌混合感染。     

扭角羚肺炎克雷伯氏菌的分离鉴定

本试验旨在报告四川省野生扭角羚自然生存过程中致病性细菌的检测及生物学特征。试验对发病死亡扭角羚病变组织进行细菌学检查及分离,对分别从肝脏、脾脏和肺脏分离得到的4株优势菌进行形态特征、生化特性和16SrDNA分子鉴定,判定为肺炎克雷伯氏菌。这4株菌对供试小白鼠均有致病性。测其LD50,分别为2.9×107、2.9×107、4.5×107和1.1×108 CFU/只。4株分离菌对供试的先锋霉素等敏感,对阿米卡星等中度敏感,对红霉素等耐药。推测这4株肺炎克雷伯氏菌是导致扭角羚死亡的主要病原菌。     

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 -