散养鸡鼠伤寒沙门氏菌的分离?鉴定?耐药性研究

从疑似感染的成年散养鸡蛋壳和发病雏鸡的肝脏、脾脏中分离到2株细菌,通过培养特性、镜检结果、生化鉴定、血清学分型等,2株分离细菌均被鉴定为鼠伤寒沙门氏菌,分别命名为AH-DY01和AH-DY02。药物敏感性检测结果表明,AH-DY01对氟苯尼考、左氧氟沙星和环丙沙星敏感,对其他12种抗生素耐药;AH-DY02对阿米卡星、氟苯尼考、左氧氟沙星、复方新诺明、庆大霉素、链霉素、环丙沙星和大观霉素敏感,对其他7种药物耐药,2株沙门氏菌均表现多重耐药性。动物回归试验结果表明,2株鼠伤寒沙门氏菌均可致死雏鸡。对分离菌的16S r DNA进行测序与遗传进化分析,结果表明AH-DY01与标准菌株ATCC-1592和ATCC13311的同源性最高,而AH-DY02与日本分离株之间的亲缘关系最近。     

Tracing the emergence of drug-resistance in coccidia (Eimeria spp.) of commercial broiler flocks medicated with decoquinate for the first time in the United Kingdom

Decoquinate is a quinolone coccidiostat introduced during 1967 as an in-feed prophylactic for broiler chickens. Despite early drug-resistance problems and its age, the drug is still used commercially worldwide. Decoquinate here serves as a valuable model in a field study that addresses the dynamics and economic impact of the development of coccidial resistance to potent synthetic anticoccidial drugs. The results of this unique, hitherto unpublished, study on the initial emergence of resistance of avian coccidia (Eimeria spp.) to a new drug in the field may be of strategic value in the continued use of decoquinate or the introduction of new drugs. The commercial performance of the first 3-5 crops of broilers to be medicated with decoquinate on each of six farms was monitored during 14 months in 1968-1969, supplemented by assessments of the species, population dynamics and decoquinate-resistance of coccidia isolated from each farm. During the rearing of each flock in a single shed on each farm, oocysts were counted in fresh faecal samples collected on three occasions, and the species were identified by their morphology if possible, supported if necessary by the biological characteristics of infections in chickens. E. acervulina was the most common species, followed by E. mitis, E. maxima, E. tenella and E. praecox. E. brunetti occurred rarely, and E. necatrix was not found. Decoquinate-resistance was evident in several species during the rearing of the first decoquinate-medicated crop on each farm, although clinical coccidiosis did not occur. It was concluded that inherently resistant mutants of E. acervulina, E. brunetti, E. maxima, E. tenella, and probably also E. mitis and E. praecox, were selected from field populations by 6 weeks during their first exposure to decoquinate. During up to four more subsequent crops, cycling of resistant parasites stimulated host immunity, which had no obvious adverse impact on commercial performance. There was no apparent seasonal effect. A hypothesis is proposed to explain the sudden and rapid emergence of quinolone-resistance in the coccidia, and why bird health was not thereby compromised in these circumstances.     

可形成生物膜的禽源产色葡萄球菌的分离鉴定及耐药性研究

从发病鸡关节腔内分离获得1株革兰氏阳性球菌,根据细菌形态、生理生化特性、动物试验,结合16S rRNA基因核苷酸序列测定、系统进化树分析及生物膜半定量检测,确定该分离菌株为可形成生物膜的的产色葡萄球菌,该菌在正常条件下不致病。药物敏感试验和耐药基因检测发现,该菌对磺胺六甲、阿奇霉素、米诺环素等8种药物敏感,对环丙沙星、头孢噻肟钠和复方新诺明中敏,而对万古霉素等13种药物低敏甚至不敏感。检测到该分离菌株包含氨基糖苷类、四环素类和磺胺类的6个耐药基因,说明这是一株多重耐药菌株,推测其耐药性与生物膜的形成有密切关系。     

木霉生防耐药因子的诱导及其生化特性研究

为了研究以含药(施佳乐)培养基筛选和诱导生防木霉菌株T-21产生耐药性生防蛋白因子———几丁质酶的效果。利用含药(施佳乐)培养基筛选诱导生防木霉菌株T-21产生几丁质酶,通过DEAE 32纤维素柱层析法进行分离纯化,用SDS-PAGE测定其分子量,并分析温度和pH值对酶活力的影响以及耐药酶对灰霉菌的抑制作用。生防木霉菌株T-21对化学农药施佳乐具有一定的抗性,浓度达1 000μg/ml时生长及产孢情况良好。通过分离纯化的几丁质酶,其分子量为45 kD,其最适反应温度为50℃,最适pH值为5.0,对灰霉菌有明显抑制作用。生防木霉菌株T-21产生的几丁质酶,可与化学杀菌剂混合使用,以增强田间的防治效果、减少化学农药的用量,进而减少化学农药对农作物的污染及残留。     

常见腐朽菌对几种防腐剂耐药性和敏感性的试验

本研究描述了常见的４种腐朽菌对ＢＢＦ、ＢＣＭ、ＣＣＡ防腐剂的耐药性和敏感性试验。结果表明，ＣＣＡ的杀菌效果最好。用琼脂扩散法，在５０ＰＰｍ的浓度下，除对裂褶菌起到抑制作用外，其它３种腐朽菌均被杀死。裂褶菌对３种防腐剂都有最大的耐药性，褶孔菌次之，而彩绒革盖菌、桦革褶菌最差。用防腐剂杀死以木块为底物的腐朽菌要比杀死以ＰＤＡ为底物的腐朽菌难得多。     

奶牛生乳中洛菲不动杆菌的分离鉴定与耐药性分析

对29份外观正常的奶牛生乳乳样进行乳品质分析和细菌学检测,利用16SrDNA序列分析鉴定乳样中分离的菌株,并进行14种药物的敏感性试验。结果表明,10份乳样有细菌检出,其中4份乳样中分离得到洛菲不动杆菌;药物敏感性结果表明,洛菲不动杆菌对复方新诺明具有较强的耐药性;乳品质分析结果表明,该4份乳样体细胞数(SCC)偏高,乳成分和部分理化性质与其他正常乳无明显区别。     

哈茨木霉T_2菌株耐药性的测定及其对几种病原菌的抑制作用研究

[目的]为提高木霉菌的生物防治效果。[方法]研究了哈茨木霉T2菌株对3种病原真菌(齐整小核菌、立枯丝核菌和香蕉枯萎病菌)的抑制作用,分析其对7种杀菌剂的耐药性,并探讨了哈茨木霉T2菌株与杀菌剂联用对立枯丝核菌和齐整小核菌的抑制作用。[结果]哈茨木霉T2菌株对病原真菌的抑制随处理时间的延长而增强。处理后120 h其对齐整小核菌、立枯丝核菌、香蕉枯萎病菌的抑制率最高,分别为63.10%、65.64%和33.84%。哈茨木霉T2菌株对多菌灵的耐药性最强,EC50为4 345.32 mg/L。在浓度为800 mg/L时多菌灵对哈茨木霉T2菌株的抑制率为13.73%,当浓度在50 mg/L以下时抑菌率几乎为0。哈茨木霉T2菌株对代森锰锌、露星较敏感。[结论]哈茨木霉T2菌株与甲霜灵联用,能明显抑制齐整小核菌、立枯丝核菌的生长。     

山西省鸡致病性大肠杆菌耐药性研究

采用纸片扩散法,对山西省11个地区的138株鸡致病性大肠杆菌用26种抗菌药物进行敏感性测定,结果,138株鸡致病性大肠杆菌对卡那霉素、阿米卡星、磷霉素、头孢唑林、头孢噻肟、头孢曲松等的高敏率为62.3%~83.3%;对氧氟沙星、庆大霉素、多黏菌素B、氟苯尼考的中敏率为50%以上;对26种抗菌药物均产生不同程度的耐药性,如恩诺沙星耐药率为81.2%,多西环素为83.3%,氨苄青霉素为85.5%,阿莫西林为87.0%,罗红霉素为89.1%,复方磺胺为99.2%,利福平为100%。所以,临床首选高敏的药物,慎重使用中敏药物,尽量不用恩诺沙星等高耐药性的药物。     

不同宿主大肠杆菌对15种抗生素抗药性差异研究

采用96孔板微量肉汤稀释法,测定SPF鸡、商品肉鸡、鸡场饲养员、医院病人等不同宿主粪样140株大肠杆菌对15种抗生素的抗药性,比较不同用药环境下大肠杆菌的抗药性差异。结果表明：SPF鸡分离菌株的抗药性最低,平均抗药性频率为46．08％,大部分菌株对8～9种抗生素存在低水平抗药性。医院病人大肠杆菌平均抗药性频率达到67．47％,多数菌株对12—13种抗生素产生抗药性。由于商品鸡场大量使用抗生素,鸡场饲养员和肉鸡分离株平均抗药性频率远高于SPF鸡,分别达80．00％和72．27％,并对12—13种抗生素产生抗药性,其中对磺胺二甲嘧啶、利福平的抗药性频率都在90％以上。建议测定区域使用抗药性频率低于50％的抗生素：头孢唑啉、头孢噻呋、硫酸黏菌素、阿米卡星。     

1株兔肺源金黄色葡萄球菌的分离鉴定及耐药分析

为了解四川某养兔场疑似金黄色葡萄球菌感染病例的病原菌及其药物敏感性,采集兔肺脏的化脓灶样品进行细菌分离纯化、染色镜检、培养特性、生化试验、16SrDNA序列鉴定及分离菌株的药敏试验和耐药基因检测。结果表明,分离鉴定出1株对小鼠具有致病性的金黄色葡萄球菌,药敏试验结果显示,金黄色葡萄球菌分离菌株具有多重耐药性,仅对头孢哌酮、头孢拉定、头孢噻吩、哌拉西林4种药物敏感,其他15种药物均耐受。耐药基因PCR检测结果显示,meca、aac(6′)/aph(2′)、 aph(3′)-III、 ant(4′,4′′)、 plw043耐药基因呈阳性,耐药表型和基因型相一致。