鸡白痢沙门氏菌耐药性的变化趋势

对１９６２－１９９８年间分离保存的３２５株鸡白痢沙门氏菌进行了药物敏感性测定。结果表明,随着时间的推移,菌株对１６种抗菌药物的耐药性呈现不同程度的上升趋势,其中对氨苄青霉素,复方磺胺,甲氧苄胺嘧啶,链霉素,四环素,壮观霉素的耐药率明显上升。     

陕西关中地区鸡白痢沙门氏菌的药敏试验

用药片扩散法测定了分离的２７株鸡白痢沙门氏菌对１６种药物的敏感性，结果表明，菌株对恩诺沙星、卡那霉素、氟哌酸、强力霉素高敏；对新霉素、痢特灵、氯霉素、庆大霉素、壮观霉素、氨苄青霉素中敏；而对复方磺胺、青霉素、链霉素、洁霉素、四环素、磺胺民恶唑等药物具有一定的耐药性。     

鸡白痢沙门氏菌耐药性的监测研究

采用WHO推荐的Kirby-Bauer法对我国部分地区1962－1999年间346株鸡白痢沙门氏菌进行了药物敏感性测定。结果表明，在近40年时间里，鸡白痢沙门氏菌对氨苄青霉素、壮观霉素、复方磺胺、磺胺异恶性唑、甲氧苄胺嘧啶、羧苄青霉素、四环素、链霉素、青霉素的耐药率显著增强（P＜0.01)。菌株的多重耐药率明显增加。60年代以二耐菌株为主（37.0%)，70年代以四耐、五耐菌株居多（60.5%)，80年代五耐、六耐、七耐菌株占大多数（80.2%)，90年代仅七耐以上菌株就达83.7%。不同年代菌株显示出不尽相同的耐药谱，且呈现出不断增宽的趋势。通过流行病学调查发现，60年代至90年代，鸡白痢沙门氏菌对青霉素、链霉素、磺胺类药物、四环素、卡那霉素、氯霉素、庆大霉素等药物的耐药性大多呈现出显著增强的变化趋势，这充分说明细菌耐药性的形成和发展与抗菌药物长期反复使用有着极为密切的关系。研究对于指导临诊合理用药及控制疾病流行具有重要的现实意义。     

鸡白痢沙门氏菌的分离与鉴定

在禽类 ,沙门氏菌可引起鸡白痢、鸡伤寒和副伤寒。其中鸡白痢沙门氏菌感染往往是终生带菌的 ,感染母鸡所产的蛋 ,高达 1/ 3带菌。带菌蛋的孵化率低 ,孵出的雏鸡的成活率也低[1,2 ] 。所以 ,鸡白痢所造成的经济损失是巨大的。2 0 0 2年 8月南宁市某养鸡场有一群 8- 11日龄的雏鸡发病 ,发病率为 10 % ,死亡率为1%。经实验室的细菌分离和一系列的生化试验 ,确诊该群雏鸡感染了鸡白痢沙门氏菌。1　材料与方法1.1　材料1.1.1　培养基血液琼脂平板、麦康凯琼脂平板、伊红美兰平板、半固体培养基等常用培养基 ,由本室制备和保存。1.1.2　生化反应管…     

1例鸡白痢沙门氏菌的分离鉴定与耐药性分析

为查明河南省新乡市某规模化蛋鸡场疑似沙门氏菌感染病例的病原，进而制定合理的治疗方案，本研究无菌采集疑似病雏鸡肠管样品，用革兰氏染色、培养特性观察、生化试验、PCR方法对其进行确诊，并进行病原回归试验，采用药敏纸片琼脂扩散法（K-B法）分析分离菌对19种常见抗生素的耐药性。结果显示，本试验成功分离了一株革兰氏阴性短杆菌，该分离菌符合鸡白痢沙门氏菌的培养特性和生化特性；PCR成功扩出invA基因，通过与GenBank数据库比对分析确定该细菌为鸡白痢沙门氏菌；用分离细菌株感染SPF鸡能复制出与自然感染一致的病例，说明鸡白痢沙门氏菌是造成本养鸡场雏鸡发病的主要病原；分离株具有较强的致病性和多重耐药性，对阿米卡星、苯唑青霉素、青霉素耐药，对复达欣、氨苄青霉素、头孢曲松等药物敏感，将敏感抗生素用于临床治疗效果明显。结合以上结果，本研究提出该病的具体防治措施，并取得了较好的效果，为鸡白痢沙门氏菌的分离鉴定及防治提供了参考，对鸡白痢沙门氏菌病病原的早期诊断和治疗具有重要临床意义。     

双黄连对鸡白痢沙门氏菌耐药性消除作用的影响

通过药敏试验证明,鸡白痢沙门氏菌对阿莫西林、氨苄西林、卡那霉素、氟苯尼考、利福平高度敏感,对头孢噻肟、头孢拉啶、头孢曲松钠、庆大霉素、泰乐菌素、硫红霉素、粘杆菌素、氧氟沙星、诺氟沙星、环丙沙星以及恩诺沙星不敏感。然后将鸡白痢沙门氏菌与双黄连作用后,部分药物的敏感性发生了变化,大多数抗菌药物的抑菌环扩大0.6～6.3mm。     

鸡白痢沙门氏菌的分离鉴定与耐药性分析

从浦东新区大团镇的规模养鸡场,采集疑似鸡白痢感染鸡的泄殖腔棉拭子,经细菌分离培养和生化鉴定,共分离到2株鸡白痢沙门氏菌。药敏试验结果显示,2株分离菌株均对环丙沙星、卡那霉素和氟苯尼考较敏感,但对四环素、氨苄西林、磺胺嘧啶产生了较强的耐药性。     

鸡白痢沙门氏菌耐药性分析

本研究通过对2002～2007年内沙门氏菌耐药性分析,发现6年中沙门氏菌的耐药现象十分严重,并有逐年上升的趋势.其中对链霉素的耐药性从很低到50%并达到稳定,对氨苄青霉素的耐受率从2002年的88.4%达到2007年的100%,对喹诺酮类药如氟哌酸,耐受性逐渐增强,从2002年的敏感到2007年的20%耐受,对四环素的耐受率也逐渐增强,2007年已完全耐受,沙门氏菌对磺胺类药物一直耐受率很高,2002年沙门氏菌对复方磺胺甲唑的耐受率为99.7%,2007年达到完全耐受,头孢菌素治疗沙门氏菌的效果较好,但耐药性也呈现上升趋势,2002年高度敏感,2007年耐受率达到40%,氯霉素的效果与头孢类相似.     

鸡白痢沙门氏菌病原的分离鉴定及耐药性分析

为鉴定新疆某些地区鸡白痢沙门氏菌主要流行株的流行现状和耐药情况,本研究采用平板凝集试验方法对有发病史的种鸡场进行现场检测,被检的750只鸡中,发现78例疑似鸡白痢沙门氏菌感染,运用沙门氏菌鉴别培养基、组织病理学观察和PCR方法进行确诊,并进行药敏试验。结果显示,疑似的78例鸡白痢沙门氏菌中有69例符合鸡白痢沙门氏菌的生化特性和病理学特点,PCR成功扩增出invA基因,分离率为9.2%,血清型诊断为D1型;其中分离菌对万古霉素和新霉素耐药性最高,耐药率分别为100.0%和81.2%,而对头孢曲松、克拉维酸和多黏菌素的敏感率达60.0%以上。本研究为养殖户和兽医工作者在净化鸡白痢沙门氏菌及临床用药方面提供参考。     

鸽感染鸡白痢沙门氏菌的诊断及药敏试验

无菌取病鸽的心脏、肝脏、肺脏、脾脏及肾脏等组织病料,进行细菌的分离培养与鉴定,结合临床症状和剖解病变,确诊病鸽为鸡白痢沙门氏菌感染。对分离菌株进行药敏试验,该菌对丁胺卡那、庆大霉素等敏感。     

Line differences in resistance to salmonella enteritidis pt4 infection

1. Four groups of hens, each of a different line, were inoculated at peak of lay, per os in the crop with 1 ml of a suspension containing 10⁹ cfu/ml Salmonella enteritidis PT4 (SE). The kinetics of SE contamination in the environment, egg shell and yolk were studied during the first 28 d post inoculation. On the day of slaughter, intestines, caeca, spleen, liver, ovary, oviduct and content were investigated for SE contamination.

2. The commercial egg‐type line L2 was found to be the most susceptible to SE. It laid many SE‐positive yolks (13.8%) and internal and faecal organs were frequently infected.

3. Certain lines are found to exhibit a degree of resistance to SE; the cause of which is unknown and might be attributed to major genes.     

Heritabilities of and genetic relationships between salmonella resistance traits in broilers

Using experimental infections, three traits for salmonella resistance were studied: mortality, survival time (in animals that died by infection), and quantitative cecal salmonella carriage at the end of the rearing period (in animals that did not die). In total, 548 animals were used; mortality was 29.2%, mean survival time was 5.97 d (n = 160), and the mean 10log of colony forming units per gram of cecal contents was 1.62 (n = 387). Genetic parameters were evaluated in bivariate threshold-linear models to account for the selective measurement of survival time and cecal carriage. Heritabilities were .06 for survival time, .09 for cecal carriage, and .12 for mortality. The genetic correlation between mortality and cecal carriage was weak (.26), which suggests that these traits are largely controlled by different genes. The genetic correlation between mortality and survival time was relatively strong (-.68). Simultaneous study of multiple traits seems to be of particular importance in judging epidemiological consequences of a possible selection for resistance. Results here indicate that selection on decreased mortality could be unfavorable for the spread of salmonella because the resulting correlated increase in survival time, implying longer shedding by infected animals, is relatively stronger than the correlated decrease in level of cecal carriage. Selection to reduce the level of cecal salmonella carriage could be done while keeping survival time constant, if so desired, because the correlation between these traits is weak (-.15).     

Antimicrobial usage and resistance in beef production

Antimicrobials are critical to contemporary high-intensity beef production. Many different antimicrobials are approved for beef cattle, and are used judiciously for animal welfare, and controversially, to promote growth and feed efficiency. Antimicrobial administration provides a powerful selective pressure that acts on the microbial community, selecting for resistance gene determinants and antimicrobial-resistant bacteria resident in the bovine flora. The bovine microbiota includes many harmless bacteria, but also opportunistic pathogens that may acquire and propagate resistance genes within the microbial community via horizontal gene transfer. Antimicrobial-resistant bovine pathogens can also complicate the prevention and treatment of infectious diseases in beef feedlots,threatening the efficiency of the beef production system. Likewise, the transmission of antimicrobial resistance genes to bovine-associated human pathogens is a potential public health concern. This review outlines current antimicrobial use practices pertaining to beef production, and explores the frequency of antimicrobial resistance in major bovine pathogens. The effect of antimicrobials on the composition of the bovine microbiota is examined, as are the effects on the beef production resistome. Antimicrobial resistance is further explored within the context of the wider beef production continuum, with emphasis on antimicrobial resistance genes in the food chain, and risk to the human population.     

Drug resistance in ostertagiasis

Benzimidazole- and levamisole-resistant Ostertagia circumcincta from sheep have been reported from several countries, but there are no reports of anthelmintic-resistant O. ostertagi in cattle, where resistance has been confirmed in controlled trials. The reasons for this may include (1) the biology of the worm, (2) avoidance of drug action by inhibition, (3) host metabolism of drugs, (4) less anthelmintic used in cattle than in sheep, (5) high costs of controlled trials, (6) lack of adequate in vitro tests to detect resistant worms and (7) lack of reporting of anthelmintic failures. Reduced efficacy of the anthelmintics levamisole and thiabendazole to adult O. ostertagi and of modern benzimidazoles to the inhibited L4 larvae has been reported in cattle. This latter effect might, in part, represent a stage-specific expression of resistance. Although anthelmintic resistance in O. ostertagi is not known to be a problem at present, it could potentially become a serious issue.     

大环内酯类驱虫药物的耐药性

大环内酯类驱虫药物包括阿维菌素类（Avermectins）和杀螨菌素类（Milbemycins）药物。阿维菌素类药物包括阿维菌素（Avermectin）、伊维菌素（Ivermectin）、多拉菌素（Doramectin）和埃普菌素（Eprinomectin）。杀螨菌素类包括莫西菌素（Moxidectin）和杀螨菌素（Milbemycin）。这类药物由于具有广谱高效的驱虫活性和较高的安全性，被认为是20年来驱虫药物研究最杰出的成就。自1981年首次批准登记以来，以后其他同类药物也陆续批准上市。目前，本类药物已在世界多个国家使用，     

川西北牦牛沙门氏菌的健康带菌调查及药敏实验

本文对来自四川省甘孜藏族自治州和阿坝藏族羌族自治州的临床健康成年牦牛进行了沙门氏菌带菌情况调查,并对其中一些沙门氏菌作了耐药情况检测。用世界卫生组织（WHO）推荐的Kirby-Bauer氏法对9株分离株进行药敏实验。结果从1 262例临床健康成年牦牛中最终分离鉴定出103株沙门氏菌,分离率约为8.17%;且9株分离株对14种抗菌素均表现为敏感,没有发现耐药菌株。     

关于综合治理兽药使用问题的分析与思考

兽药的规范使用事关人民群众"舌尖上的安全"。通过调研发现,当前我国畜禽养殖环节兽药使用具有"一减一增、一多一缺"的特点,而造成兽药不规范使用的主要原因是市场调节激励机制还未形成、政府部门管理服务能力还有待提高。在借鉴了各地规范兽药使用上的探索与实践后,建议按照精细管理、风险分级、量化监督的原则,在夯实现有监督执法、专项整治等各项监管工作的基础上,疏堵结合,实施"兽药规范使用五大工程",循序渐进地推动兽药使用问题的综合治理。