鸭源多杀性巴氏杆菌对磺胺类药物的耐药性检测及耐药基因分析

为明确鸭源多杀性巴氏杆菌对磺胺类药物的耐药性及耐药基因的分布特征,试验采用琼脂二倍稀释法对分离自福建、广东和江西等地的89株鸭源多杀性巴氏杆菌进行甲氧苄啶/磺胺甲噁唑的耐受性检测,用PCR法检测各耐药菌株的磺胺类耐药基因(sul1、sul2和sul3),并利用多位点序列分型(MLST)分析耐药菌株间的亲缘关系。结果显示,33株鸭源多杀性巴氏杆菌对甲氧苄啶/磺胺甲噁唑耐受,耐药率为37.1%(33/89);在耐药菌株中,sul1、sul2和sul3基因检出率分别为100%(33/33)、97.0%(32/33)和21.2%(7/33),其中sul1和sul2基因同时检出率为97.0%(32/33),sul1、sul2和sul3基因同时检出率为21.2%(7/33);所有耐药菌株均属于ST129型。以上结果表明,鸭源多杀性巴氏杆菌对磺胺类药物具有一定的耐药性,其中的耐药菌株都属于同一序列型ST129,均携带有sul1耐药基因,且绝大多数耐药菌株同时携带sul1与sul2两种耐药基因,提示在福建、广东和江西等地需慎用磺胺类药物来防治该细菌的感染。     

18株不同源多杀性巴氏杆菌耐药性分析

通过微量稀释法药敏试验及四环素类耐药基因的扩增对18株不同源多杀性巴氏杆菌进行耐药性分析。并采用PCR及其产物测序检测上述菌株中一类整合酶携带率。结果表明,18株不同源的多杀性巴氏杆菌对氯霉素的耐药率为83.33%,对四环素、强力霉素与庆大霉素的耐药率为50%~61.11%,对氧氟沙星、卡那霉素、恩诺沙星与氟苯尼考的耐药率为27.78%~38.89%。18株菌株均未检测到tet A耐药基因,22.22%的多杀性巴氏杆菌携带tet B耐药基因,5.56%的多杀性巴氏杆菌携带tet O耐药基因,tet K与tet Q两种耐药基因的携带率均为27.28%,而对于tet G的携带率为100%,Ⅰ型整合酶携带率为22.22%。本研究为进一步研究多杀性巴氏杆菌耐药机制及跨物种传播奠定了基础。     

鸭源多杀性巴氏杆菌对磺胺类药物的耐药性检测及耐药基因分析

为明确鸭源多杀性巴氏杆菌对磺胺类药物的耐药性及耐药基因的分布特征,试验采用琼脂二倍稀释法对分离自福建、广东和江西等地的89株鸭源多杀性巴氏杆菌进行甲氧苄啶/磺胺甲噁唑的耐受性检测,用PCR法检测各耐药菌株的磺胺类耐药基因(sul1、sul2和sul3),并利用多位点序列分型(MLST)分析耐药菌株间的亲缘关系。结果显示,33株鸭源多杀性巴氏杆菌对甲氧苄啶/磺胺甲噁唑耐受,耐药率为37.1%(33/89);在耐药菌株中,sul1、sul2和sul3基因检出率分别为100%(33/33)、97.0%(32/33)和21.2%(7/33),其中sul1和sul2基因同时检出率为97.0%(32/33),sul1、sul2和sul3基因同时检出率为21.2%(7/33);所有耐药菌株均属于ST129型。以上结果表明,鸭源多杀性巴氏杆菌对磺胺类药物具有一定的耐药性,其中的耐药菌株都属于同一序列型ST129,均携带有sul1耐药基因,且绝大多数耐药菌株同时携带sul1与sul2两种耐药基因,提示在福建、广东和江西等地需慎用磺胺类药物来防治该细菌的感染。     

禽源多杀性巴氏杆菌多位点序列分型研究

为了解国内禽源多杀性巴氏杆菌流行情况,对分离自18省份的84株多杀性巴氏杆菌采用荚膜多重PCR分型和多位点序列分型对其血清型和基因型进行鉴定。结果表明:禽源多杀性巴氏杆菌主要以血清A型为主,占96.4%(81/84);多位点序列分型可将禽源多杀性巴氏杆菌分为5种ST型,其中ST129为主要流行型,占94.0%(79/84)。本研究为我国禽源多杀性巴氏杆菌的流行病学监测和基因多样性提供了数据支持。     

10株禽源多杀性巴氏杆菌药物敏感性与质粒多样性分析

为探究禽源多杀性巴氏杆菌是否携带质粒与耐药性的关系,分别采用培养法、纸片法、碱裂解法等对10株病原菌(FC1701~FC1710)进行复苏培养、药物敏感性试验、质粒观察。结果发现:有5株携带有大小不同的质粒,其大小在1~20 kb之间,质粒数量为1~4个不等;10株多杀性巴氏杆菌均出现多重耐药,且所有菌株对氟苯尼考敏感,对克林霉素不敏感;携带有质粒的菌株耐药数量多于未携带质粒的菌株耐药数量,多黏菌素、利福平和左氧氟沙星这三种耐受药物只在携带质粒的菌株中出现。试验结果表明,禽源多杀性巴氏杆菌质粒的耐药可能与多黏菌素、利福平和左氧氟沙星的耐药有关。     

巴氏杆菌对链霉素和磺胺耐药机制的研究

根据巴氏杆菌的链霉素耐药基因StrA和磺胺耐药基因SulⅡ序列设计2对引物,以临床分离的4株禽源巴氏杆菌耐药株为模板,扩增出StrA、SulⅡ基因序列。经克隆和核苷酸序列测定,克隆的基因与文献报道的耐药基因序列(NC-001774)有较高的同源性(≥98.9%);试验结果显示,耐药株巴氏杆菌对链霉素和磺胺耐药性的差异与StrA、SulⅡ基因突变有关(耐药性高的菌株基因突变率高)。试验中所有耐药菌均在StrA基因编码的第204位氨基酸处存在突变;所有耐药菌均在SulⅡ基因编码的第159,246,384,584,590,591,597,582位氨基酸处存在突变,上述突变基因可能是导致巴氏杆菌对链霉素和磺胺产生耐药性的主要因素。     

河南地区猪源肠外致病性大肠杆菌的分离鉴定与耐药性试验

为了解猪源肠外致病性大肠杆菌在河南地区的流行及耐药性,本试验于2016—2018年从河南省61家猪场送检的发病猪中,采集肺脏等病料,进行大肠杆菌的分离与鉴定,并用微量稀释法测定分离菌株的耐药性,采取PCR法检测分离菌株中氟苯尼考耐药基因(floR)、Ⅰ类整合酶基因的携带情况,通过Ⅰ类整合子基因盒可变区序列的BLAST比对,分析其耐药基因携带情况。结果显示,经细菌分离共获得17株肠外致病性大肠杆菌,检出率为27.86%(17/61);分离菌株对氨苄西林、磺胺甲噁唑、四环素、氟苯尼考和氯霉素等药物耐药率为100%,对多黏菌素耐药率为41.18%,分离菌株均呈多重耐药;在分离菌株中,floR、Ⅰ类整合子携带率均为100%,Ⅰ类整合子基因盒主要携带dfrA17-aadA5、aadA22-aadA23-aadA25、dfrA12、dfrA12-aadA2和floR等类型耐药基因谱。本试验结果表明河南地区猪源肠外致病性大肠杆菌具有一定的流行性,且耐药问题十分严重,极易导致临床上治疗失败,应引起重视。     

牛源A型多杀性巴氏杆菌hyaD基因缺失株的构建及其在小鼠上的交叉保护性分析

hyaD为A型多杀性巴氏杆菌荚膜多糖合成相关基因,为探讨该基因对多杀性巴氏杆菌毒力及其免疫保护特性的影响,本研究利用同源重组方法,构建了牛源A型多杀性巴氏杆菌CQ2株（PmCQ2）的hyaD基因缺失株（ΔhyaD）。结果发现,与野生株相比,ΔhyaD的荚膜产生量及其感染后在脏器中的细菌定殖量均显著下降,其毒力显著降低。细胞试验发现,ΔhyaD更易黏附于巨噬细胞,被吞噬数量显著多于野生株,致使巨噬细胞相关炎性因子表达显著上调。hyaD基因的缺失,可调控与荚膜合成、LPS合成转运、铁转运等相关的基因表达显著下调,促使相关保护性抗原基因表达显著上调。以制备的PmCQ2株和ΔhyaD株灭活苗免疫小鼠（加强免疫1次）,免疫后第21天分别采用同源和异源多杀性巴氏杆菌攻毒,ΔhyaD株免疫小鼠肺组织感染后24 h无明显或轻微病理损伤,对牛源A型、B型和F型多杀性巴氏杆菌的免疫保护率分别为100%、100%和80%,对兔源、猪源和禽源A型多杀性巴氏杆菌的免疫保护率分别为90%、100%、100%;而野生株PmCQ2除对牛源A型多杀性巴氏杆菌的保护率在80%以上外,对牛源B型和F型及兔、猪、禽源A型多杀性巴氏杆菌均无明显交叉保护作用。研究结果表明,hyaD基因可通过调控荚膜产生及毒力相关因子表达影响菌株毒力;hyaD基因缺失可调控相关交叉保护性抗原表达,赋予菌株交叉免疫保护特性。该研究为多杀性巴氏杆菌通用型疫苗的研发提供了参考。     

6株山羊源多杀性巴氏杆菌血清型、耐药性及致病性分析

为了研究6株分离自四川省内江市2个养殖场患病山羊支气管的多杀性巴氏杆菌的主要生物学特性,试验采用特异性PCR方法鉴定多杀性巴氏杆菌血清型,采用纸片扩散法(Kirby-Bauer)评价了临床分离菌株对14种抗菌药物的敏感性,采用Reed-Muench法测定分离菌株对昆明小鼠的半数致死量(LD_(50)),分析其致病性。结果表明:在6株多杀性巴氏杆菌中,4株为A型,2株为B型。分离菌株对青霉素和林可霉素100%耐药,而对复方新诺明和氟苯尼考具有较高的敏感性。分离菌株对昆明小鼠的半数致死量均大于5×10~(8.0) cfu/0.5 mL,致病性较弱。说明本次分离的山羊源多杀性巴氏杆菌菌株为弱毒株,丰富了我国山羊源多杀性巴氏杆菌的生物学特征,为其感染的防控提供了有用的信息。     

上海市猪源多杀性巴氏杆菌分离鉴定及其耐药性分析

本研究旨在调查上海市猪源多杀性巴氏杆菌对临床常用抗菌药的耐药情况,为该病的药物预防与治疗提供科学依据。2014~2015年在上海市11个规模化养猪场采集疑似多杀性巴氏杆菌感染的病料共计116份,采用细菌分离培养及PCR方法,分离鉴定出20株多杀性巴氏杆菌。采用纸片法测定了分离菌株对20种临床常用抗菌药的敏感性,结果表明,所有菌株对阿莫西林克拉维酸、头孢曲松、恩诺沙星、氟苯尼考、阿奇霉素和多黏菌素B敏感,这6种药物可作为本地区控制本病的首选药物。然而,超过50%的菌株对青霉素(65.0%)、复方新诺明(65.0%)、氨苄西林(60.0%)、链霉素(60.0%)、四环素(60.0%)耐药。耐药谱分析显示,85.0%的菌株对4~7种抗菌药耐药。本研究结果表明上海市猪源多杀性巴氏杆菌对临床常用抗菌药物耐药较严重,应加强养殖场猪多杀性巴氏杆菌的耐药性监测与防控。     

癸氧喹酯干混悬剂含量测定的改进

采用高效液相色谱法测定癸氧喹酯干混悬剂的含量,在2-250μg/mL范围内,峰面积的常用对数与进样量浓度的常用对数呈良好的线性关系,R^2=1(n=5),平均回收率为99.24%~99.51%,RSD在0.05%~0.28%。此方法分析时间短,样品前处理简便、定量结果准确,重现性好,结果满意,为其质量控制提供了依据。     

猪毛色遗传的研究进展

本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。     

商会自治的基石——商会自治规范研究

在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。     

獭兔睾丸的组织学观察

家兔作为一种实验动物 ,推动了繁殖技术的发展。本试验通过对不同年龄公獭兔的睾丸进行组织学观察、测定 ,研究精子的发生规律 ,为系统地进行繁殖生理工作提供依据。1　材料与方法选 60日龄、75日龄、90日龄 3个年龄公獭兔各5只 ,用外科手术法摘取两侧睾丸 ,放入 Bouin氏液中固定 ,二甲苯透明 ,石蜡包埋 ,切成 5～ 8μm切片 ,H.E.染色。在显微镜下观察 ,并进行定量组织学指标测定及差异性比较。2　结果和讨论2 .1　睾丸定量组织学指标的测定结果　见表 1。表 1　獭兔睾丸定量组织学指标　　　μm,个 /精细管60日龄 75日龄 90日龄曲细精管…     

中华人民共和国农业部公告 第267号

为贯彻落实《兽药生产质量管理规范》(简称《兽药GMP》),进一步推动兽药GMP实施进程,我部制定了《兽药生产质量管理规范检查验收办法》,现予公告。本公告自2003年6月1日起施行。附件:兽药生产质量管理规范检查验收办法二○○三年四月十日第一章 总则 第一条 为推动《兽药生产质量管理规范》(以下简称兽药GMP)的实施,规范兽药GMP检查验收工作,制定本办法。 第二条 农业部负责全国兽药GMP管理和检查验收工作;负责制修订兽药GMP检查验收管理规定;负责兽药GMP检查员队伍建设和监督管理工作,负责国际兽药贸易中GMP互认工作。 …     

鸡败血支原体垂直传播模式及其阻断方法

以国际标准强毒Ｒ株人工感染非免疫产蛋鸡,定时扑杀,分别从鼻窦、眶下孔、气管、肺、气囊、卵巢和输卵管分离ＭＧ,并收集感染鸡所产蛋分离ＭＧ。结果表明,人工感染４８小时后上、下呼吸道及肺已被全面感染,９６小时气囊已被感染,１２０小时输卵管已能分离到ＭＧ,卵巢始终分离不到ＭＧ。人工感染鸡自１４４小时便能在其所产蛋中分离出ＭＧ。药物治疗能在７２小时内消除感染,油乳剂苗则需２４天后逐渐降低蛋内ＭＧ分离率,药物卵内注射、种蛋药浴、高温处理均能杀死卵内ＭＧ,但以研制的种蛋浸泡剂药浴效果为最好。     

Observations of fracture of the anconeal process of the ulna of swine

Fractures of the anconeal process of 5 pigs ranging in age from 4 to 8 months were studied radiographically and histologically. Clinically, animals with a fracture of the anconeal process had a "tight," restricted gait. In pigs at 4.5 months of age, a radiolucent line through the base of the anconeal process was composed of fibrocartilage, fibrous connective tissue, and hyaline cartilage. Subperiosteal proliferation of woven bone was located along the cranial surface of the olecranon, adjacent to the base of the anconeal process. In older animals, the radiolucent line through the anconeal process contained variable amounts of fibrous connective tissue and fibrocartilage. The proliferation of subperiosteal bone at the base of the anconeal process formed a "buttress callus" which retained a radiolucent area between the callus and the proximal surface of the anconeal process. The latter region of radiolucency was continuous with the transversely oriented line that traversed the base of the anconeal process.     

Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF

Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo.     

Comparison of 2 methods of centesis of the bursa of the biceps brachii tendon of horses

REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air.