上海地区猪源链球菌分离株的病原特性鉴定

1997－1999年从上海地区分离出15株猪源链球菌，结合培养特性、生化特性及血清定型等对其进行了鉴定。其形态、染色及培养特性基本符合链球菌的特点，大多具有α或β溶血，生化试验结果不稳定。用国际通用的链球菌A－G乳胶分型诊断液和猪链球菌1、2型标准阳性血清检测5株分离菌，4株为C群链球菌，1株为2型猪链球菌，1株为B群链球菌，1株为D群链球菌，1株与A群和C群有交叉反应，7株不在其检测范围。小鼠对15株分离菌的敏感性有所不同。本试验表明，上海地区猪链球菌病的病原已不再是单一的C群链球菌。对新出现的2型猪链球菌，应引起足够重视。     

猪源链球菌的分离与鉴定

从浙江地区98例发病样品猪猪体共分离到56(57％)株猪源链球菌，对12株典型分离株进行培养特性、生化特性及血清型的鉴定，多数具α或β溶血，其中C群链球菌8株。L群链球菌1株，2型猪链球菌2株。未定群1株。小鼠对12株分离株的敏感性有一定的差异。结果表明：浙江地区分离到的猪链球菌已不是单一的C群链球菌，且C群中也不是以往的马链球菌兽疫链球菌亚种。而是停乳链球菌似马亚种。并首次分离到猪链球菌2型。     

锦州地区猪链球菌病病原的分离鉴定

从锦州地区的6个区县发病猪场采集18份疑似猪链球菌病病料进行细菌的分离和生化鉴定,分离到链球菌18株。对分离到的细菌进行系统的病原学研究,其形态、染色均符合链球菌的特点,具α或β溶血,用国际通用的链球菌乳胶凝集试验和玻片凝集试验对分离的18株链球菌进行血清型鉴定。该研究对预防和控制锦州地区猪链球菌病的流行提供了重要依据。     

新疆石河子地区某规模奶牛场奶牛乳房炎链球菌的分离鉴定及药敏试验

对准备进行抗生素治疗的24头患乳房炎奶牛的36个乳区样品进行链球菌的分离与鉴定,共分离出12株链球菌。通过形态学特征观察、生化特性鉴定、16S r RNA鉴定,最终确定12株分离菌均为链球菌,并对其做耐药性分析,为后期奶牛乳房炎治疗提供指导。     

新疆地区3株驴源马链球菌马亚种新SeM基因型的鉴定与进化分析

从新疆地区某驴养殖场获得了3株驴腺疫链球菌分离株HTP133、HTP123和HTP232.为了解这3株驴腺疫链球菌的生物学特性和确定其分子分型,本研究对其进行了生化特性、药敏特性的检测,对16S rRNA进行序列对比分析,并利用PCR扩增SeM等位基因和测序鉴定其基因型.研究结果表明3株分离菌均为马链球菌马亚种.药敏试...     

猪链球菌2型JX分离株的生物学特性

从临床表现为脑膜炎、关节炎及败血症的发病猪分离到2株细菌，分别命名为JX02和JX03，经鉴定其形态、染色及培养特性均符合链球菌的特点，具α或β溶血，生化试验结果不稳定。用猪链球菌2型、1型和9型抗血清进行凝集试验，结果2株菌均能与猪链球2型抗血清凝集，其中1株菌对小鼠和家兔均有致病性，另1株菌只能致死家兔。PCR均能扩增2株菌的主要毒力因子基因。表明发病猪的病原不同于以往的C群链球菌，不是马链球菌兽疫亚种，而是属于R群的猪链球菌。     

猪链球菌的分离鉴定

从豫北的安阳县、滑县等地猪场采集的病料中分离出了5株猪链球菌。经细菌分离培养、生化试验、兰氏分群A-G诊断试剂鉴定，其中E群链球菌2株，C群链球菌2株，D群链球菌1株。药敏试验结果表明，分离的链球菌对氨苄西林、头孢他啶和头孢曲松高度敏感，对青霉素、复方新诺明和土霉素等药物产生耐药性。     

马源马链球菌兽疫亚种新疆株的分离鉴定及遗传特性分析

为了解马源马链球菌兽疫亚种（S.zooepidemicus）新疆分离株马链球菌兽疫亚种类M蛋白（SzM）基因的分子进化与变异情况,为该菌引起的感染性疾病的防控提供依据,本试验对新疆地区某马场采集的病马淋巴结样品进行病原菌的分离培养和生化鉴定,并对分离菌株进行药物敏感性试验。根据已发表的马源SzM基因序列设计引物,对其SzM基因进行PCR扩增及序列测定。将获得的SzM序列与GenBank中不同动物源马链球菌兽疫亚种分离株序列进行同源性比对和遗传进化分析。结果显示,分离得到了一株革兰氏阳性链球菌,将其命名为马链球菌兽疫亚种ZMSY15-1。药物敏感性试验结果表明,分离菌株对青霉素、磺胺嘧啶钠耐药,对其他14种药物均敏感。序列分析结果显示,马链球菌兽疫亚种ZMSY15-1与国内外不同动物源分离株SzM基因氨基酸同源性为56.0%~70.0%。遗传进化分析结果显示,这些菌株可分为4个群。马链球菌兽疫亚种ZMSY15-1与猪源分离株SzM蛋白的氨基酸同源性为59.9%,分别属于2个不同的群,其与美国马源分离株NH55426亲缘关系最近。本试验结果可丰富国内马源马链球菌兽疫亚种SzM基因的信息数据,为马链球菌兽疫亚种的致病机制研究和预防控制提供参考依据。     

马源马链球菌兽疫亚种新疆株的分离鉴定及遗传特性分析

为了解马源马链球菌兽疫亚种(S.zooepidemicus)新疆分离株马链球菌兽疫亚种类M蛋白(SzM)基因的分子进化与变异情况,为该菌引起的感染性疾病的防控提供依据,本试验对新疆地区某马场采集的病马淋巴结样品进行病原菌的分离培养和生化鉴定,并对分离菌株进行药物敏感性试验。根据已发表的马源SzM基因序列设计引物,对其SzM基因进行PCR扩增及序列测定。将获得的SzM序列与GenBank中不同动物源马链球菌兽疫亚种分离株序列进行同源性比对和遗传进化分析。结果显示,分离得到了一株革兰氏阳性链球菌,将其命名为马链球菌兽疫亚种ZMSY15-1。药物敏感性试验结果表明,分离菌株对青霉素、磺胺嘧啶钠耐药,对其他14种药物均敏感。序列分析结果显示,马链球菌兽疫亚种ZMSY15-1与国内外不同动物源分离株SzM基因氨基酸同源性为56.0%～70.0%。遗传进化分析结果显示,这些菌株可分为4个群。马链球菌兽疫亚种ZMSY15-1与猪源分离株SzM蛋白的氨基酸同源性为59.9%,分别属于2个不同的群,其与美国马源分离株NH55426亲缘关系最近。本试验结果可丰富国内马源马链球菌兽疫亚种SzM基因的信息数据,为马链球菌兽疫亚种的致病机制研究和预防控制提供参考依据。     

广东罗非鱼无乳链球菌分离鉴定及生物学特性分析

本研究旨在明确当前罗非鱼无乳链球菌流行状况和生物学特性,为鱼源无乳链球菌病防控提供新的数据。本研究于2019—2020年,从广东罗非鱼主养区茂名、湛江地区采集病样进行无乳链球菌的分离鉴定。用PCR方法对分离株血清型及4个主要毒力基因进行检测,通过纸片法对分离菌株进行31种抗菌药物药敏试验和多重耐药研究,利用斑马鱼模型进行了致病性试验。结果显示：从261份病样中分离到35株无乳链球菌;血清型检测表明无乳链球菌分离株的血清型均为Ia型;主要毒力基因的检测证明,cylE、sodA、gapC基因在所有鱼源分离株及人源、牛源和鱼源参考株中检出率均为100%,而scpB只在人源参考菌株中检出;药敏试验结果发现,无乳链球菌分离株对19种抗菌药敏感率为90%以上,对6种抗菌药耐药率为50%以上,分离株的耐药基因型和表型部分一致,无乳链球菌分离株均多重耐药,其中5重及以上耐药的菌株为27株,占总菌株数的77.1%;斑马鱼致病试验表明,无乳链球菌分离株可导致斑马鱼不同程度的发病死亡。本研究明确了当前罗非鱼源无乳链球菌的血清型、毒力基因、耐药特性和致病性,为广东乃至全国罗非鱼无乳链球菌病的防控提供了参考。     

Assay of protein A in Staphylococcus hyicus subsp. hyicus by ELISA and immunoelectron microscopy

The presence and quantity of protein A in Staphylococcus hyicus subsp. hyicus isolates were examined by an enzyme-linked immunosorbent assay (ELISA) and immunoelectron microscopy. Cell-bound protein A was demonstrated in 45 (94%) of 48 isolates from diseased pigs and in 113 (86%) of 132 isolates from healthy pigs by ELISA using peroxidase-conjugated rabbit antibody, but was not found in isolates from chickens and cows. Most of these swine isolates contained about 100 to 300 ng of cell-bound protein A/ml. Extracellular protein A was not detected in any isolates from pigs, chickens or cows. In the immunoelectron microscopy assay, swine isolates were labeled with goat anti-mouse IgG conjugated to colloidal gold particles, but chicken and cow isolates were not labeled.     

Differentiation of vaccine strains and Georgia field isolates of infectious laryngotracheitis virus by their restriction endonuclease fragment patterns

Seven restriction endonucleases (REs) were used to cleave the DNA from seven vaccine strains of infectious laryngotracheitis (ILT) virus and from six Georgia field isolates of ILT virus. After electrophoresis of the resulting RE fragments, the patterns were compared in order to differentiate strains of ILT virus. The six chicken-embryo-origin (CEO) vaccines were identical with each RE, but the tissue-culture-origin (TCO) vaccine strain differed from the CEO vaccines using five of the REs. Four of the six field isolates were identical by each RE, but two field isolates differed from each other and from the four identical field isolates on the basis of patterns produced by some but not all of the REs. The four identical field isolates could not be differentiated from the CEO vaccine strains by any RE, but the other two field isolates were not identical to either strain of vaccine virus. This work demonstrates that differentiable strains of ILT virus exist in the United States and that viruses other than vaccine viruses are involved in field outbreaks of ILT.     

Hemagglutinating activity and immunological properties of Haemophilus paragallinarum field isolates in Japan

Four field isolates (S4, S10, S15, and S17) of Haemophilus paragallinarum were recovered from chickens affected with infectious coryza in widely separated regions of Japan. Their hemagglutinating (HA) activity and immunological properties were compared with those of strain 221 of serovar A/1 and strains Modesto and S1 of serovar C/2. When treated with potassium thiocyanate or hyaluronidase, all the isolates showed HA activity against formaldehyde-fixed chicken erythrocytes but not against fresh chicken erythrocytes. In the hemagglutination-inhibition (HI) test, the isolates cross-reacted with strains Modesto and S1 but not with strain 221. The immunological properties of these isolates, as determined by cross-protection tests, were similar to those of strain S1 and, to a lesser degree, strain Modesto, but not to strain 221. Our results indicated that the four field isolates belong to serovar C/2 and that the HI test is a suitable method for serotyping H. paragallinarum.     

动物源性耐甲氧西林葡萄球菌耐药表型及基因型鉴定

通过耐药表型及基因型检测对临床分离的41株葡萄球菌进行了鉴定，鉴定出耐甲氧西林金黄色葡萄球菌（MRSA）16株，耐甲氧西林凝固酶阴性葡萄球菌(MRCNS)4株。耐甲氧西林葡萄球菌（MRS）阳性率达到48.8%，这提示兽医临床必须提高对MRS的重视，并为临床鉴定MRS提供了可借鉴的方法。     

Identification of hog cholera viral isolates by use of monoclonal antibodies to pestiviruses

A collection of 90 field isolates of hog cholera virus (HCV) was used to test the specificity of four hybridoma cell lines secreting monoclonal antibodies against pestiviruses. Reaction of virus isolates and monoclonal antibodies was controlled by an indirect immunofluorescence assay (IFA). Two monoclonal antibodies which had been generated against HC virus strain "Alfort 187" were reactive only with HCV field isolates and an HCV reference strain but not with bovine viral diarrhoea virus (BVDV) reference strains. Two other monoclonal antibodies (generated against BVDV, strain NADL) reacted only with BVDV reference strains but not with HCV field isolates, although with 3 of these strains focal reactions involving only a few cells were detected. The ability to discriminate between both viruses is a diagnostic need which may be fulfilled by these monoclonal antibodies.     

Susceptibility of Salmonella isolated from fish feed factories to disinfectants and air-drying at surfaces

The objective of this work was to determine whether persistence of certain Salmonella isolates in fish feed factories involved enhanced resistance to disinfectants or air-drying. Salmonella isolates known to be persistent in fish feed factories and Salmonella isolates from other origins were tested for their sensitivity to nine disinfectants by using a suspension test. More than 5log(10)reduction in viable count for all isolates was only achieved by two of the disinfectants at 80% of the lowest recommended user concentration. However, Salmonella isolates from fish feed factories were not more resistant to disinfectants compared to Salmonella from other origins. For four of the disinfectants, presence of fish feed had a more adverse effect on disinfection efficacy compared to the protein bovine serum albumin (BSA). In general, the Salmonella isolates were more resistant to disinfection than Escherichia coli DSM 682, a strain recommended in testing of disinfectants. The Salmonella isolates were also tested for their ability to survive air-drying at stainless steel surfaces, but there were no differences in survival of isolates from fish feed factories compared to isolates of other origin. In conclusion the Salmonella isolates from fish feed factories were not particularly resistant to disinfection or air-drying at surfaces. The data show that disinfectants to be used against Salmonella should be thoroughly tested and selected, since not all disinfectants appear to be effective against Salmonella.     

Characterisation of the outer membrane protein antigens of British field isolates of Moraxella bovis

Outer membranes of a single isolate of Moraxella bovis were prepared and their purity evaluated by a comparison of the iodinated proteins from whole cells and on outer membranes. The protein patterns of the outer membranes of 10 isolates were examined by SDS-polyacrylamide gel electrophoresis, and the antigenic relationship between proteins of different isolates determined by immunoblotting, using antiserum produced against the outer membrane of the single isolate of M. bovis. The overall protein pattern of the different isolates was similar although not identical, but, significantly, only three separate immunogenic proteins were common to all the isolates under examination.     

Molecular characterization of Blastocystis isolates from primates

Twelve Blastocystis isolates from primates were analyzed genetically by polymerase chain reaction (PCR) using diagnostic primers and PCR-restriction fragment length polymorphism (RFLP) of SSUrDNA. Two distinct genotypes, subtype 1 and a variant of subtype 1, were detected in two and six of the 12 isolates, respectively. The RFLP profiles of the isolates designated as subtype 1 were identical to the profile of ribodeme 1. The RFLP profiles of the six isolates designated as variants of subtype 1 were different from the profile of the variant of subtype 1 from a human reported previously. The other four isolates were not amplified with any diagnostic primers, but three of them showed the same RFLP profiles as ribodeme 6. This study was the first genomic analysis of Blastocystis isolates from primates, and showed the genetic similarity between the isolates from primates and the genotypes of Blastocystis hominis. However, it was unclear whether the isolates examined were zoonotic or not. Therefore, it is necessary to reveal the phylogenetic relationships between the isolates from primates and the multiple genotypes of B. hominis.     

Brachyspira pilosicoli isolated from pigs in Japan

Two of four weak beta-hemolytic isolates of intestinal spirochetes isolated from pigs in Japan possessed a unique base alignment of TTTTTT on the 16S ribosomal DNA of Brachyspira pilosicoli and were identified as B. pilosicoli. The other two isolates were not identified by this technique. The identified isolates were 4.2 to 11 microm in length and 0.2 to 0.3 microm in diameter, 4 periplasmic flagella at each end were observed dominantly. The isolates were hippurate positive but indole negative. This is the first report on the isolation of B. pilosicoli from pigs in Japan.