牦牛源溶血致病性表皮葡萄球菌的分离鉴定及药敏分析

对1株分离自西藏那曲地区养殖场有出血性症状牦牛的致病性菌进行分子鉴定及药敏分析,为西藏地区牦牛出血性疾病提供治疗依据。通过对病死牦牛肺脏、肝脏进行细菌分离纯化获得疑似菌株,对所得疑似菌株进行形态学观察与哥伦比亚血平板试验筛选出疑似致病菌株,再对疑似致病菌株进行生理生化鉴定试验、16S rDNA通用引物检测及测序、同源性比对,后经药敏试验得到该疑似致病菌株的敏感药物,最后通过动物回归试验验证其敏感药物的治疗效果。结果表明,通过对病死牦牛肺脏、肝脏分离纯化获得6株疑似菌株,经形态学观察试验、哥伦比亚血平板试验筛选出1株具有溶血性的革兰氏阳性球菌S-4。经生理生化鉴定试验、16S rDNA测序、同源性比对,鉴定S-4菌株为表皮葡萄球菌;药敏试验结果显示,S-4菌株对恩诺沙星、新霉素、多黏菌素B、卡那霉素、环丙沙星敏感,对氟苯尼考、多西环素中介敏感,对链霉素、红霉素、四环素、青霉素、头孢氨苄耐受;动物回归试验显示,该菌株具有致病性,且恩诺沙星、新霉素、卡那霉素3种药物治疗效果良好,多黏菌素B、环丙沙星治疗效果差。本试验获得1株具有致病性的牦牛源表皮葡萄球菌,该致病菌在养殖过程中可使用恩诺沙星、新霉素、卡那霉素3种药物进行治疗。     

1株奶牛源松鼠葡萄球菌的分离鉴定及耐药性分析

为确定奶牛垫料中是否含有病原菌并深入了解垫料中优势生长菌的类型、耐药性及致病性等情况,本试验进行了细菌分离培养、革兰染色镜检、生化试验鉴定、16S rDNA序列分析及同源性比对、药敏试验、小鼠致病性试验。结果显示,分离菌在普通营养琼脂平板上形成圆形、表面光滑的白色菌落,血琼脂平板上形成黏稠、较大的白色菌落。革兰染色镜检结果显示,分离菌为革兰阳性,球型,呈葡萄串状排列,或单个散落。生化试验结果显示,分离菌对木糖、葡萄糖、麦芽糖、果糖、乳糖、硝酸盐还原等呈阳性反应,而蜜二糖、木糖醇、山梨醇、尿素、V-P反应等呈阴性反应。16S rDNA序列分析结果显示,扩增的16S rDNA序列长度为1 298 bp,与松鼠葡萄球菌的核苷酸同源性达99.85%~100%;系统进化树结果显示,分离菌与松鼠葡萄球菌处于同一分支。动物试验结果表明,分离菌株对试验小鼠有较强的致病性,以0.2 mL/只（7.9×10⁸ CFU/mL）菌液的剂量接种小鼠,在48 h内死亡率为60%（3/5）。药敏特性分析结果显示,分离菌株对复方新诺明、氨苄西林等7种药物敏感,对克林霉素、头孢噻肟和头孢呋辛中度敏感,对青霉素、红霉素和林可霉素耐药。本研究为奶牛源松鼠葡萄球菌的分离鉴定及防控提供了参考依据。     

青海省祁连县羊布鲁氏病发生情况调查及防治

羊布鲁氏杆菌病俗称布病,是由布鲁氏杆菌感染引起的一种人畜共患病。近年,我国家畜饲养量不断增加,动物及其产品流通不断频繁,部分地区布鲁氏杆菌病呈现上升趋势,严重威胁当地畜牧养殖产业和人民群众的身体健康。该文主要就祁连县羊布鲁氏杆菌病的发生情况进行调查,提出相应的防治对策。     

鸡毒支原体研究概况

鸡毒支原体(MG)是对养禽业危害很大的支原体,主要导致禽类慢性呼吸道疾病(CRD),以禽的结膜炎、产蛋率及饲料转换率下降、屠宰率下降等为主要特征。MG可通过垂直和水平传播方式在鸡群中传播,每年给全球家禽产业带来巨大经济损失。随着对MG细胞表面抗原黏附素蛋白(pMGA)和PvpA、GapA的结构与功能研究的深入,K株、TG5株等MG疫苗研究也取得较大进展。由于抗生素的滥用,MG基因中也发生耐药突变,产生了QRDRs等抗药结构,导致MG在耐药性上也出现新的特点。论文主要对国内外MG的疫苗开发、耐药情况和检测技术等进行综述,旨在对家禽MG的综合防控提供借鉴。     

甘肃省某奶牛场肠杆菌性乳房炎主要病原菌的分离鉴定与耐药性分析

为查明甘肃省某奶牛场发生临床型奶牛乳房炎的主要病原菌并选择治疗用敏感药物,随机无菌采集了6份临床型病牛乳样和1份大罐乳样,采用划线分离、菌落形态观察、革兰染色镜检、生化鉴定及16S rDNA序列分析等方法进行细菌分离鉴定,同时采用K-B法测定主要分离菌株对抗菌药物的敏感性。结果表明,从临床型乳房炎乳样中分离鉴定出大肠埃希菌、芽胞杆菌、凝固酶阴性葡萄球菌(腐生葡萄球菌)3种细菌,其中大肠埃希菌的分离率最高,为66.67%;从大罐奶样中也分离出大肠埃希菌。药敏试验结果表明,大肠埃希菌对氨苄青霉素、阿莫西林、头孢噻吩、杆菌肽、红霉素均存在不同程度的耐药,耐药率为29%~100%;对诺氟沙星、恩诺沙星、氟苯尼考、头孢哌酮等药物敏感。说明此次牛场临床型乳房炎的主要病原菌是大肠埃希菌、葡萄球菌和芽胞杆菌,而且分离的大肠埃希菌具有多重耐药性。根据检测分析结果,给奶牛场提出针对性的防控措施,临床型乳房炎的发病率下降,病情得以控制。     

应用分子靶点药物治疗犬肥大细胞瘤的研究进展

犬肥大细胞瘤因其恶性率和转移率都较高,并且常规化疗药物副作用较强,患犬生存期和生存质量显著下降,因此急需新型的药物进行治疗。近几年,治疗肿瘤的分子靶点药物凭借其疗效好、副作用低的特点,受到越来越广泛的关注,特别是在治疗犬肥大细胞瘤的应用中效果显著。论文重点介绍了欧美小动物临床最常用的伊马替尼、托赛拉尼、马赛替尼这3种以异常KIT为靶点的药物及其药物作用机理及药效,最后介绍了由c-kit基因二次突变所导致的耐药问题及其预防措施,期望能对我国小动物临床医师和科研工作者有所启发。     

Prevalence and antimicrobial resistance of Salmonella isolates in Moroccan laying hens farms

Increasing emergence of salmonellosis presents a threat to the effective control of foodborne disease in humans. The purpose of this study was to evaluate the prevalence of drug susceptibility and molecular characteristics of non-typhoidal Salmonella (NTS) isolated from laying hens (LH) in 3 Moroccan regions, Rabat-Salé-Zemmour-Zaër (RSZZ), Souss-Massa-Drâa (SMD), and the grand Casablanca (GC). A total of 351 samples were collected from 30 consumer egg laying houses at the end of the egg laying period from April to July 2011. Sixty-four out of these 351 examined samples were contaminated by Salmonella. The Salmonella isolated strains were then serotyped and tested for drug susceptibility and analyzed by polymerase chain reaction (PCR) for the presence of the invasion-associated genes invA and spvC and nalidixic acid resistance-associated qnr gene. The prevalence of NTS infection in LH was estimated to be 73.3%. Seven Salmonella enterica serovars were identified: Enteritidis (37.5%), Kentucky (31.2%), Infantis (10.9%), Typhimurium (6.2%), Thompson (6.2%), Agona (4.6%), and Amsterdam (3.1%). Drug susceptibility testing showed that 65.6% of Salmonella were resistant to at least one antibiotic and 25% were resistant to ciprofloxacin. All isolates were positive for the invasion gene invA and 28% of them were positive for the virulence gene spvC. All nalidixic acid-resistant S. Enteritidis isolates were negative for qnr plasmid genes. Our findings clearly suggest the necessity to establish an NTS monitoring and control program for LH in Morocco.     

Suspected levamisole intoxication in calves

CASE HISTORY: A group of 32 Friesian and four Hereford calves, 3–4 months old with body weights between 100–120?kg, were purchased from a weaner sale. On arrival at the property the Hereford calves were treated with a combination anthelmintic containing 2?g/L abamectin and 80?g/L levamisole hydrochloride. Shortly afterwards they developed tremors and frothing from the mouth, and two died overnight. The Friesian calves were treated with the same anthelmintic on the following day, when some showed hypersalivation and frothing from the mouth.

CLINICAL FINDINGS: Examination of the three most severely affected Friesian calves revealed severe nicotinic-type symptoms including hypersalivation, frothing from the mouth, muscle tremors, recumbency, rapid respiration, hyperaesthesia, and central nervous system depression. Other calves showed mild to moderate signs of intoxication including restlessness, tail switching, salivation, tremors, frequent defaecation, mild colic and jaw chomping. Two calves died shortly afterwards. An adverse drug event investigation revealed that the formulation and quality of the anthelmintic was within the correct specification, and that the drench gun was functioning correctly.

DIAGNOSIS: Suspected levamisole intoxication due to a combination of possible overdosing, dehydration, and stress caused by transportation and prolonged yarding.

CLINICAL RELEVANCE: Susceptibility to levamisole toxicity in New Zealand calves can be increased if factors like dehydration or stress are present. Levamisole has a narrow margin of safety, and overdosing in calves can easily occur if the dose rate is not based on their actual weight or health status.     

新疆部分地区生乳中金黄色葡萄球菌的分离鉴定及耐药性分析

【目的】探明新疆部分地区生乳中金黄色葡萄球菌流行情况及耐药性,为该地区生乳中金黄色葡萄球菌的监测及保障生乳质量安全提供理论依据。【方法】试验随机从南北疆规模化奶牛场采集110份生乳样品。采用增菌培养、分离纯化、革兰氏染色、生化鉴定及PCR法对奶样中金黄色葡萄球菌进行分离鉴定,并利用微量肉汤稀释法及PCR方法对金黄色葡萄球菌进行16种抗菌药物的耐药表型及耐药基因分析。【结果】从110份奶样中分离出18株金黄色葡萄球菌,分离株呈浅黄色、光滑凸起的圆形菌落,革兰氏染色镜检呈紫色、短链状排列的革兰氏阳性菌,生化试验结果符合金黄色葡萄球菌生化特点,经16S rDNA及nuc基因PCR扩增鉴定为金黄色葡萄球菌,分离率为16.36%(18/110)。药敏试验结果显示,金黄色葡萄球菌分离株对氨苄西林、青霉素及磺胺异噁唑具有较高的耐药性,耐药率分别为100%、83.33%和77.78%,而对万古霉素、复方新诺明、苯唑西林、头孢噻吩、头孢噻呋、利福昔明及环丙沙星7种抗菌药物高度敏感,敏感率分别为100%、100%、94.44%、94.44%、94.44%、94.44%和94.44%。其中有14株金黄色葡萄球菌为多重耐药菌,多重耐药率为77.78%。耐药基因检测结果显示,大环内酯类耐药基因ermB检出率最高,为50.00%,其次为β-内酰胺类耐药基因mecA,检出率为27.28%,磺胺类耐药基因Sul1的检出率为22.22%。【结论】新疆奶牛场生乳中分离的金黄色葡萄球菌的流行及耐药情况仍较严重,且存在多重耐药现象,因此,对生乳中金黄色葡萄球菌耐药性的监测有重要意义。