奶牛乳房炎金黄色葡萄球菌疫苗研究进展

奶牛乳房炎是影响乳品工业经济效益的重要疾病之一,引起奶牛乳房炎的致病菌约有150多种,但金黄色葡萄球菌是引起奶牛乳房炎的主要病原。由它引起的乳房炎很难治愈,而且对抗生素产生耐药性的菌株已经相当普遍,因此使用预防或治疗性疫苗防治乳房炎就成为首选。然而金黄色葡萄球菌的致病力由许多不同的因子(如黏附素、荚膜等)决定,这使得制备非常有效的疫苗变得很困难。本文就这些致病因子在疫苗研制方面的进展做一简要介绍。     

奶牛乳房炎金黄色葡萄球菌黏附素研究进展

金黄色葡萄球菌的黏附素是其引起奶牛乳房炎的关键因素之一,与金黄色葡萄球菌在奶牛乳房中定植有关的的黏附素主要是ClfA、FnBPA和FnBPB3种。曾有对金黄色葡萄球菌黏附素表达调控的研究发现,在金黄色葡萄球菌感染的早期主要表达黏附素,之后才表达毒素和荚膜,所以人们认为,对金黄色葡萄球菌的黏附进行干预,可以减少或阻止毒素和荚膜的表达,而以黏附素作为靶位进行疫苗研制可能是预防奶牛金黄色葡萄球菌性乳房炎的有效途径。国外对金黄色葡萄球菌的黏附素的研究历史相对较久,并且也取得了许多可喜成绩,而国内对金黄色葡萄球菌的研究相对滞后。因此,研究金黄色葡萄球菌黏附素对预防由金黄色葡萄球菌引起的奶牛乳房炎具有广阔的前景。     

奶牛乳房炎金黄色葡萄球菌黏附素疫苗的研究进展

奶牛乳房炎不仅是影响乳品工业经济效益的主要疾病之一,而且还危害到公共卫生和人类健康。金黄色葡萄球菌是引起奶牛乳房炎的主要病原,由于金黄色葡萄球菌具有细胞内定植和对抗生素极易产生耐药性的特点,使得用抗生素治疗的效果越来越差,因此使用疫苗进行防制就成为首选。大量研究证实,金黄色葡萄球菌的黏附素识别并特异性的结合到组织、细胞的特定分子上是感染的关键,因此,阻断细菌的黏附和在黏膜表面的定植,可能是预防感染最有效的策略,为奶牛金黄色葡萄球菌性乳房炎疫苗的研制提供了新的途径。     

奶牛乳腺炎金黄色葡萄球菌ClfA A区和FnBPA基因的克隆与串联表达

<正>金黄色葡萄球菌是奶牛乳腺炎的重要病原[1],近50%乳腺炎由该菌引起[2],主要感染乳房、乳头导管或损伤的乳头。致病性金黄色葡萄球菌对抗生素的敏感性较低,防治较难[3]。近年研究证实,在金黄色葡萄球菌感染早期,黏附素是最重要的致病因子,只有当金黄色葡萄球菌黏附到宿主细胞上,毒素和荚膜才能表达。与金黄色葡萄球菌在奶牛乳房中定植有关的黏附素主要是Clf A和Fn BPA。Clf A的黏附作用与基因的一个区域有     

如何进行奶牛乳房炎金黄色葡萄球菌疫苗的合理评估

奶牛乳房炎是造成全球奶业经济损失的主要原因,而金黄色葡萄球菌是最主要的病原菌。本文系统、直观地对研究奶牛乳房炎金黄色葡萄球菌疫苗的科研结论进行量化总结和评估,目的是为奶牛乳房炎疫苗的研发提供新思路,为设计合理的奶牛乳房炎疫苗给动物评估试验方案提供科学依据。本文在Pubmed、Science数据库和CNKI数据库对＂奶牛乳房炎疫苗＂类的文章进行了合理的电子检索,然后对细菌疫苗、细菌类毒素疫苗、DNA-重组蛋白疫苗、单一的重组蛋白疫苗等方面的科研论文从试验设计、方法、疫苗类型和研究结果 4个方面进行了全面的分析。结果表明,采用DNA、重组蛋白新技术的疫苗和传统的细菌疫苗已取得良好效果,疫苗可以成为预防和控制金黄色葡萄球菌性奶牛乳房炎的最好或最有前景的一种途径。但是研究方法差异和双盲试验的缺乏阻碍对疫苗效果的合理评估。     

牛源耐甲氧西林金黄色葡萄球菌研究进展

金黄色葡萄球菌是引起奶牛乳房炎的最主要病原菌之一。然而,在治疗奶牛乳房炎的过程中由于抗生素滥用,造成乳汁中药物残留及耐药菌株增多。近年来,尤其是耐甲氧西林金黄色葡萄球菌(MRSA)检出率逐年呈上升趋势,成为危害人畜健康的重要致病菌之一。同时也给奶牛乳房炎的治疗带来巨大的挑战。论文对牛源耐甲氧西林金黄色葡萄球菌检测方法、流行病学、致病性及致病因子、耐药机制、预防与治疗措施及未来发展前景及展望进行了综述,希望为深入研究MRSA,减少其耐药性,研制有效的药物和疫苗起到参考作用。     

奶牛乳房炎疫苗研究进展

奶牛乳房炎是奶牛乳腺组织炎症，主要为乳腺组织感染病原微生物所致，是奶牛的常见病、多发病。引起奶牛乳房炎的致病菌约为一百五十多种，以金黄色葡萄球菌、链球菌和大肠杆菌为主，约占整个奶牛乳房炎病例的９０％以上。利用疫苗来控制传染性疾病是一种经典的预防手段。利用疫苗防治奶牛乳房炎有很多优点：首先，没有乳汁残留问题；其次，疫苗有助于降低乳腺感染的严重程度，控制亚临床型乳房炎；最后是操作简便，费用低廉。１ 金黄色葡萄球菌疫苗、在乳房炎致病菌中金黄色葡萄球菌在最为广泛，在乳腺组织防御系统中，中性粒细胞对金黄色…     

半合成青霉素与β-内酰胺酶抑制剂对奶牛乳房炎致病菌体外联合药敏的研究

奶牛乳房炎由多种病原微生物引起,金黄色葡萄球菌、无乳链球菌、停乳链球菌、乳房链球菌和大肠杆菌5种是最常见的病原[1].青霉素类抗生素是治疗乳房炎的常用药物,但由于不合理使用,金黄色葡萄球菌、链球菌、大肠杆菌等奶牛乳房炎的主要病原菌对该类抗生素有较强的耐药性.     

乳房炎源性金黄色葡萄球菌生物被膜检测及药敏试验

金黄色葡萄球菌是奶牛乳房炎的最主要病原之一,由其引起的奶牛乳房炎发病率高、防治困难,常常会给奶业造成巨大经济损失,对食品安全造成巨大威胁.以新疆阿克苏地区奶牛乳房炎性金黄色葡萄球菌分离株为研究对象,详细观察了菌株在刚果红培养基上的形态,并通过K-B扩散法分析了5株金黄色葡萄球菌乳房炎分离株对19种抗生素的耐药情况.结果表明,5株金黄色葡萄球菌均具有生物被膜形成能力,且对青霉素、链霉素、氨苄西林和四环素等常用抗生素完全耐药,对万古霉素、环丙沙星、诺氟沙星、阿米卡星等抗生素中度敏感,而对恩诺沙星、头孢西丁和头孢噻肟3种抗生素高度敏感.研究结果提示,乳房炎性金黄色葡萄球菌具有较强的耐药性,而这种耐药性可能与其生物被膜形成有关.     

奶牛金黄色葡萄球菌乳房炎菌苗佐剂研究现状

金黄色葡萄球菌是引起奶牛乳房炎的重要致病菌。近年来 ,科学工作者对于预防奶牛金黄色葡萄球菌乳房炎的疫苗进行了大量研究 ,但由于金黄色葡萄球菌存在着荚膜的原因 ,疫苗效果不理想 ,需要佐剂提高疫苗的免疫原性。目前研究的佐剂主要有弗氏佐剂、氢氧化铝、细胞因子、微球、人参提取物及其皂甙Rb1等。其中弗氏佐剂、氢氧化铝容易引起局部副作用使其应用受到限制 ,而细胞因子、微球和人参皂甙等佐剂因其效果确实 ,安全性好值得应用推广。     

胸腺嘧啶依赖型金黄色葡萄球菌小菌落突变株的分离鉴定

本试验对由患慢性奶牛乳房炎奶样中分离出的1株疑似金黄色葡萄球菌小菌落突变株(SCVs)进行形态观察、金黄色葡萄球菌相关保守基因片段(nuc、nucA、16S rDNA) 多重PCR扩增鉴定、药敏试验、生理生化特性研究及补偿试验。结果显示分离出1株金黄色葡萄球菌SCVs,该菌含有金黄色葡萄球菌菌种特异性基因nuc和nucA;与金黄色葡萄球菌质控菌株ATCC 25923的抑菌圈大小明显不同;菌落形态主要表现为菌落细小、生长缓慢、溶血能力下降;凝固酶活性下降;耐盐能力降低;革兰氏染色为革兰氏阳性球菌,呈葡萄状排列;补偿试验鉴定该金黄色葡萄球菌SCVs为胸腺嘧啶依赖型。结果表明成功分离鉴定出1株胸腺嘧啶依赖型金黄色葡萄球菌SCVs,为由金黄色葡萄球菌SCVs引起的奶牛慢性乳房炎的预防和控制及其致病机制的研究奠定前期基础。     

小鼠模型在奶牛金黄色葡萄球菌乳房炎中的应用

金黄色葡萄球菌是奶牛乳房炎的主要致病菌之一,由其引发的感染应用现有的抗生素很难治愈。因该病发病机制和临床发展过程较为复杂,故与治疗相关的研究工作进展缓慢。目前,国内外研究人员多通过建立动物模型,对金黄色葡萄球菌进行研究。笔者旨在通过建立金黄色葡萄球菌乳房炎小鼠模型对金黄色葡萄球菌表面蛋白、毒力因子及其变异菌株进行研究,为该病的发病机理和新型抗菌药物的研制奠定方向。     

奶牛金葡菌乳房炎抗性的转录组及表观遗传学研究进展

奶牛乳房炎是一种常见疾病,对动物福利和奶牛场的经济效益产生不利影响.患有乳房炎的奶牛,尤其是金葡菌乳房炎的奶牛,其牛奶产量和品质大幅下降,严重的还会导致奶牛丧失生产能力.目前,奶牛乳房炎相关的研究已成为畜牧业的重点课题.本文综述和分析了近几年奶牛乳房炎及奶牛金葡菌乳房炎的主要研究领域和现状,主要对其抗病遗传育种在转录组...     

金黄色葡萄球菌天然抗生物被膜物质研究进展

奶牛乳房炎是造成奶牛养殖业巨大经济损失的疾病,金黄色葡萄球菌是导致奶牛乳房炎感染的主要致病菌之一。以生物被膜的群落形式存在的金黄色葡萄球菌,更易逃避宿主免疫系统、降低药物敏感性,从而导致奶牛乳房炎反复发作,最终形成顽固性乳房炎。研究显示,天然抗生物被膜物质对金黄色葡萄球菌生物被膜的抑制作用明显,可作为新的抗菌药物应用于奶牛乳房炎的防治。对金黄色葡萄球菌生物被膜耐药机制和天然抗金黄色葡萄球菌生物被膜物质的最新研究进展进行了概述,以期对防治金黄色葡萄球菌导致的奶牛乳房炎提供参考。     

Coagulase-negative staphylococci as cause of bovine mastitis- not so different from Staphylococcus aureus?

In this review of the literature, mastitis-causing coagulase-negative staphylococci (CNS) and Staphylococcus aureus are compared. Staphylococci are the bacteria most commonly isolated from bovine mastitis, and CNS are now predominant over S. aureus in most countries. CNS include various species, but only a few prevail in bovine mastitis. S. aureus can cause clinical mastitis, but often causes subclinical mastitis, which remains persistent and increases milk somatic cell count. CNS, traditionally regarded as minor pathogens, seem to lack the ability to cause severe mastitis. CNS can, however, persist in the mammary gland and moderately increase milk somatic cell count. Resistance to various antimicrobials is more common in CNS than in S. aureus, but CNS mastitis responds much better to antimicrobial treatment than S. aureus mastitis.     

Molecular types and antibiotic resistance of Staphylococcus aureus isolates from bovine mastitis in a single herd in China

The molecular diversity, antibiotic resistance patterns and presence of resistance genes were determined in Staphylococcus aureus isolates from cases of bovine mastitis in a dairy cattle herd in China. Multiple locus variable number tandem repeat analysis was used for molecular typing. Resistance was determined through minimum inhibitory concentrations and resistance genes were detected by PCR. There was low molecular diversity; one predominant strain (type I) accounted for the majority of cases of S. aureus mastitis in the herd and this strain had a high frequency of resistance to penicillin and tetracycline. The most prevalent resistance genes were blaZ, ermC and tetM.     

Treatment of clinical mastitis. Using antimicrobial susceptibility profiles for treatment decisions.

Antibiotic susceptibility of clinical mastitis pathogens has traditionally been determined using the agar diffusion method that was designed to reflect the antibiotic concentration in serum and interstitial fluid of human patients after receiving oral or intravenous administration. The validity of applying agar diffusion susceptibility breakpoints derived from humans to the treatment of bovine mastitis has not been established and is extremely questionable because (1) bovine milk pH and electrolyte, fat, protein, and leukocyte concentrations, growth factor composition, and pharmacokinetic profiles are different than those for human plasma and (2) human bacterial pathogens are often different from bovine mastitis pathogens. Also, antibiotics are distributed unevenly in an inflamed gland, and high antibiotic concentrations can alter neutrophil morphology or function in vitro and thereby inhibit bacterial clearance in vivo. The current cost of antibiotic susceptibility testing is $12 to $20 per test. Because the dairy industry is economically driven, any diagnostic test should be validated, have appropriate sensitivity and specificity, and have an acceptable economic return on the cost of testing before it can be routinely recommended. In the authors' opinion, antimicrobial susceptibility testing of mastitis pathogens has not been adequately validated for most mastitis pathogens and antibiotics; therefore, the authors do not currently recommend the use of susceptibility testing to guide treatment decisions for individual cows. Additional research is needed to further define the role, if any, that antimicrobial susceptibility testing should play in the treatment of clinical mastitis.     

Characterization of cell wall associated proteins of a Staphylococcus aureus isolated from bovine mastitis case by a proteomic approach

Staphylococcus aureus causes different pathologies in humans and animals. In particular, it is involved in intramammary infections in cows, causing economic losses and milk-safety problems. Although it is well-known that surface components (proteins and capsular polysaccharides) and exotoxins are virulence factors involved in the pathogenesis of bovine mastitis, less is known about the precise biochemical identity of such molecules. Therefore, mapping of surface proteins using specific disease- and environment-isolates provides a benchmark for strain comparison of pathogens with different pathogenic characteristics and antibiotic resistance mechanism and can aid in defining specific vaccine and therapeutic targets. In this study, we used a proteomic approach on protein extracts of lysostaphin-treated S. aureus in isotonic conditions, to produce a reproducible and well resolved 2-D electrophoresis (2-DE) reference map of surface associated proteins of isolated S. aureus from a case of bovine mastitis. The most abundant protein components were identified by Matrix assisted laser desorption ionisation-time of flight (MALDI-TOF) mass spectrometry.     

Resistance of mastitis pathogens in northern Germany

The data of 1692 susceptibility tests acquired from April 2003 through March 2004 in the mastitis laboratory of the Institute for Food Quality and Safety were summarized in order to help veterinarians confronted with acute mastitis in choosing the appropriate antibiotic. Two thirds of the milk samples were infected with gram-positive cocci. One third of these were identified as Streptococcus (S.) uberis, one fourth as Staphylococcus (S.) aureus. All isolates (100%) of S. uberis, S. dysgalactiae, S. agalactiae and Arcanobacterium pyogenes were susceptible to Penicillin and Ampicillin. Concering S. aureus, nearly 100% of the isolates were susceptible to Oxacillin, Cephalothin, Cefacetril, Cefquinom and Neomycin, but only 88% of the isolates were sensitive to Penicillin, Ampicillin and Cefoperazon. The gram-negative rods (Escherichia (E.) coli, Klebsiella spp. and Pseudomonas spp.) displayed an irregular resistance pattern. More than 93% of all examined isolates including Pseudomonas spp. were susceptible to Colistin. The sensitivity of E. coli and Klebsiella spp.to Marbofloxacin, Enrofloxacin and Cefquinom exceeded 96%. Thus, the susceptibility of gram-positive mastitis pathogens to common antibiotics is favourable. Because the highly effective Colistin is no longer approved for local therapy, the situation for gram-negative bacteria is more difficult.     

Staphylococcal Nuclease in Udder Secretions of Cows with Acute Mastitis

High concentrations of nuclease produced by Staphylococcus aureus were demonstrated within a few hours by direct examination of udder secretions from cows with a severe staphylococcal mastitis. A positive correlation between the nuclease concentration and the severity of the mastitis was found. The cows with high nuclease concentrations were generally young individuals and/or in the first 2 weeks of the lactation period. Most had a low titre of antibodies against staphylococcal nuclease. Two-thirds of the cows in which high nuclease concentrations were demonstrated were culled or died because of the mastitis attack.The role which nuclease plays for staphylococcal virulence is discussed, and it is concluded that nuclease contributes to the pathogenicity of S. aureus.