诸氏鲻虾虎鱼致病性创伤弧菌的分离与鉴定

从患病的诸氏鲻虾虎鱼分离病原,研究其致病性。通过形态学观察、生理生化特性、HSP60序列扩增及系统发育树分析等方法系统鉴定,并进行了人工感染和毒力基因检测。结果表明,从患病的诸氏鲻虾虎鱼肝脏组织分离到1株革兰阴性杆菌,编号PYMc14-2,回归感染试验证实该菌株为诸氏鲻虾虎鱼的病原菌,毒力基因hemo检测结果阳性。生化特性结果与创伤弧菌类似,PCR扩增获得的486bp的HSP60基因序列与创伤弧菌(登录号AF230955.1)同源性达94%;系统进化树分析表明,PYMc14-2与创伤弧菌(登录号AF230955.1)聚为一簇,初步鉴定该菌为创伤弧菌。     

半滑舌鳎源创伤弧菌分离鉴定与药敏试验

为查明引起河北省昌黎县某海水养殖场半滑舌鳎患病及死亡的病原菌,本研究从半滑舌鳎肝、脾、腮、肠道分离纯化得到1株优势菌株,对其进行了理化鉴定和16S rDNA序列分析、致病性试验、毒力基因检测和中西药的药敏试验。结果显示,分离菌为创伤弧菌(V.vulnificus),序列比对显示与创伤弧菌同源性为100%,菌株命名为V.vulnificus QHD-1。动物回归试验证明该菌是半滑舌鳎的病原菌。小鼠半数致死量(LD_(50))为2.4×10~6 CFU/mL,携带毒力基因溶细胞素(vvhA)、细胞毒素(rtxA)、铁载体(viuB)、荚膜多糖(wza)等。西药药敏试验结果显示,分离菌株V.vulnificus QHD-1对氟苯尼考等7种药物敏感,对氧氟沙星等5种药物中敏;对头孢拉定、土霉素等6种药物耐药;中药药敏试验结果表明,苏木、诃子、乌梅、五倍子抑抑菌效果较好;最小抑菌浓度(MIC)和最小杀菌浓度(MBC)均为1.9～7.8 g/L;中药联合抑菌试验结果表明,黄芩和黄柏组合、五倍子和黄芩组合、乌梅和五倍子组合、艾叶和荆芥组合、板蓝根和黄芩组合对创伤弧菌表现协同作用。研究结果证明V.vulnificus QHD-1对鱼和小鼠具有较强的致病性,具有一定的公共卫生危害性;同时药敏试验结果为该地区鱼病的防治提供了依据。     

海产品中副溶血弧菌的分离与鉴定

副溶血弧菌（Vibrio Paraaemolyticus)是一种致病性嗜盐菌，常引起人类食物中毒，通过对四种不同海产品的检测，发现该菌检出率很高，其中，海虾中的检出率高达90％，海产鱼为70％，贝类为60％，海蟹为40％，平均检出率为65％，动物试验证实，该菌致病性较强。     

Isolation of an atypical Leptospira strain assigned to the Sejroe serogroup from a water buffalo in Brazil

The isolation of leptospires from buffaloes worldwide is still limited to a few strains. Thus, the aim of this study was to describe the first Leptospira isolate from buffalo urine, assigned to the Sejroe serogroup, which does not belong to the Wolffi subgroup, traditionally isolated in Brazil. A total of 244 urine samples of water buffaloes (Bubalus bubalis) raised in the Brazilian Amazon were subjected to bacteriological culturing and polymerase chain reaction (PCR) for the detection of leptospires. The obtained isolate was characterized by serogrouping using polyclonal antibodies, partial DNA sequencing, Hardjo-Bovis-specific PCR, multiple-locus variable-number tandem repeat analysis (MLVA/VNTR) and experimental infection in hamsters. PCR was performed on the urine samples; 11/244 were positive (4.5 %) for Leptospira, and only one isolate was recovered (0.4 %). Regarding characterization, the isolate was assigned to the Sejroe serogroup with high titers (12,800) for the Saxkoebing and Sejroe serovar antisera. The isolate was negative for Hardjo-Bovis-specific PCR, and the species Leptospira borgpetersenii was identified by DNA sequencing. The MLVA results showed that the VNTR profile of the isolate was 1−2-5, compatible with that of serovars Sejroe/Istrica. In the experimental infection in hamsters, the animals did not develop clinical signs, and no macroscopic lesions were observed on the organs at necropsy; however, the strain was detected in the kidneys, uterus, and testicles of the animals. The isolate described herein highlights infection by Sejroe strains that may be overlooked in buffaloes and that may be different from those normally isolated and used in serological studies.     

Isolation and molecular characterisation of equine rotaviruses from Germany

A total of 26 rotavirus positive faecal samples of diarrhoeal foals, and 8 equine rotavirus isolates were examined. Viral RNA patterns were generated, G typing was performed by PCR, and a P[12]-specific DNA probe was developed for P typing. Furthermore, five equine rotavirus isolates were sequenced in the genomic regions coding for VP7 and part of VP4. Rotaviruses of genotype G3 P[12] were found in 22 faecal samples and G14 P[12] type could be found in 4 faecal samples. These findings confirm that in Germany G3 P[12] is the predominating type of equine rotaviruses.     

Isolation and Identification of Vibrio metschnicovii from Domestic Ducks and Geese

Seven Vibrio-like field strains of German origin were isolated culturally from diseased domesticated ducks, muscovy ducks and geese, and were compared with reference strains NCTC 8443 (type strain) and NCTC 11170 of Vibrio metschnicovii using classical phenotypic and chemotaxonomic tests. Some V. cholerae strains were included in the chemotaxonomic tests for comparative purposes. On the basis of the classical phenotypic characteristics studied and the numerical analysis of the whole-cell fatty acid patterns, the Vibrio-like field strains were identified as Vibrio metschnicovii. The identification tables and the database of the computer software of two commercial micro-identification kits (API-20 NE, ID-32 E) did not identify the field strains. Of the reference strains used, only NCTC 8443 was correctly identified by the ID-32 E software.     

副溶血性弧菌分离鉴定

利用TCBS琼脂培养基和科玛嘉弧菌显色培养基对细菌进行分离,采用糖分解试验、氧化酶试验、IMVi试验等生化试验鉴定海产品中副溶血性弧菌,为防治疾病提供依据。     

Isolation of atypical enteropathogenic Escherichia coli from chicken and chicken-derived products

1. Atypical enteropathogenic Escherichia coli (EPEC) strains from chicken and chicken-derived products were isolated and characterised.

2. The strains presented a wide variety of serotypes, some have been reported in other animal species (O2:H40, O5:H40) and in children with diarrhoea (O8:H-). Most of the strains carried intimin β.

3. The results indicate that chicken and chicken products are important sources of atypical EPEC strains that could be associated with human disease, and highlight the need to improve hygiene practices in chicken slaughtering and meat handling.

     

Isolation of H13N2 influenza A virus from turkeys and surface water.

This is the first report of the isolation of H13N2 avian influenza virus (AIV) subtype from domestic turkeys. This subtype was also isolated from nearby surface water. The observation of large numbers of gulls in close association with turkeys on range before the virus isolations suggests that this virus subtype was transmitted from gulls to range turkeys. Turkey flocks infected by this virus subtype did not show any clinical signs of the disease, although seroconversion did occur. The H13N2 isolates were found to be non-pathogenic in chickens.     

Isolation and identification of Vibrio metschnicovii from domestic ducks and geese.

Seven Vibrio-like field strains of German origin were isolated culturally from diseased domesticated ducks, muscovy ducks and geese, and were compared with reference strains NCTC 8443 (type strain) and NCTC 11170 of Vibrio metschnicovii using classical phenotypic and chemotaxonomic tests. Some V. cholerae strains were included in the chemotaxonomic tests for comparative purposes. On the basis of the classical phenotypic characteristics studied and the numerical analysis of the whole-cell fatty acid patterns, the Vibrio-like field strains were identified as Vibrio metschnicovii. The identification tables and the database of the computer software of two commercial micro-identification kits (API-20 NE, ID-32 E) did not identify the field strains. Of the reference strains used, only NCTC 8443 was correctly identified by the ID-32 E software.     

创伤弧菌和副溶血弧菌双重LAMP检测方法的建立及初步应用

为建立创伤弧菌和副溶血弧菌的双重环介导等温扩增(loop-mediated isothermal amplification,LAMP)检测方法,本试验以创伤弧菌metalloprotease基因和副溶血弧菌ompA基因为靶点设计LAMP扩增引物,并在内引物间添加不同的酶切位点,通过对反应时间和温度的优化及酶切反应,成功建立了双重LAMP检测方法,并对其检测特异性、灵敏度和实际应用性进行了研究。结果显示,62℃反应45min时可同时检测到2种弧菌的存在,通过限制性内切酶酶切,可准确区分2种弧菌。该方法比普通PCR检测方法灵敏度高102~103倍。选择17株细菌菌株作为检测模板,发现除创伤弧菌和副溶血弧菌反应结果呈阳性外,其他均为阴性。以大菱鲆作为实验动物,检测双重LAMP技术的实际应用可能,该方法可准确检测并鉴定出组织和血液中感染的细菌种类,其灵敏度可达374~410CFU/g(mL)。SYBR GreenⅠ是一种结合于DNA双链小沟中的荧光染料,反应产物加入该染料后,极易用肉眼判别。本试验成功建立了创伤弧菌和副溶血弧菌的双重LAMP检测方法,该方法可用于水产养殖中病原菌的早期诊断。     

Isolation of Mycoplasma meleagridis from free-ranging birds of prey in Germany

In this study tracheal swabs and air sac biopsies of 68 raptors of different species that were found injured or debilitated in Germany were investigated for the occurrence of mycoplasmas. Mycoplasma meleagridis, Mycoplasma falconis, Mycoplasma buteonis, Mycoplasma gypis and five mycoplasma isolates not identified so far could be isolated from 32 (47%) birds. Mycoplasma meleagridis could be detected in five birds. These birds did not show clinical signs or histopathological alterations in air sac biopsies related to the infection.     

Thymic cysts in harbor porpoises (Phocoena phocoena) from the German North Sea, Baltic Sea, and waters of Greenland.

Thymic cysts have not been previously reported in harbor porpoises (Phocoena phocoena). Two hundred forty stranded or "by-caught" harbor porpoises originating from the German North Sea and Baltic Sea and 14 animals from the waters of Greenland were necropsied. Thymuses of 78 porpoises of the North Sea and Baltic Sea were considered suitable for histopathologic examination based on the extent of postmortem autolysis. Immunohistochemistry using an anti-cytokeratin antibody was employed to demonstrate thymic epithelial structures in selected cases. Thymic macrocysts were rare and were only found in animals > or =7 years of age. Thymic microcysts, lined by a single cytokeratin-positive cell layer, were common in involuting thymuses, and the prevalence increased with advancing age. Thymic cysts might have arisen from degenerating Hassall's corpuscles or condensed epithelial reticulum. Thymuses were easily identified macroscopically in most adult healthy harbor porpoises, suggesting that physiological thymic involution proceeds slowly in this species.