一种快速检测抗沙门氏菌O抗原单克隆抗体的微量间接血凝试验

用热酚—水法提取沙门氏菌脂多糖(LPS),经pH8.0热处理后,致敏醛化的绵羊红血球,建立了一种快速检测抗沙门氏菌O抗原单克隆抗体的微量间接血凝试验。用致敏血球在96孔V型血凝板上与杂交瘤培养上清作凝集试验,数秒钟即能判定结果。本试验具有快速的特点,且有一定的敏感性。     

Surface Glucan Structures in Aeromonas spp.

Aeromonas spp. are generally found in aquatic environments, although they have also been isolated from both fresh and processed food. These Gram-negative, rod-shaped bacteria are mostly infective to poikilothermic animals, although they are also considered opportunistic pathogens of both aquatic and terrestrial homeotherms, and some species have been associated with gastrointestinal and extraintestinal septicemic infections in humans. Among the different pathogenic factors associated with virulence, several cell-surface glucans have been shown to contribute to colonization and survival of Aeromonas pathogenic strains, in different hosts. Lipopolysaccharide (LPS), capsule and α-glucan structures, for instance, have been shown to play important roles in bacterial–host interactions related to pathogenesis, such as adherence, biofilm formation, or immune evasion. In addition, glycosylation of both polar and lateral flagella has been shown to be mandatory for flagella production and motility in different Aeromonas strains, and has also been associated with increased bacterial adhesion, biofilm formation, and induction of the host proinflammatory response. The main aspects of these structures are covered in this review.     

应用抗O抗原单克隆抗体对692个沙门氏菌分离株的分群鉴定

应用抗沙门氏菌菌体抗原O_1、O_2、O_3、O_4、O_7、O_8、O_9,O_(11)、O_(12)、O_(19)一组单克隆抗体(单抗)对692个沙门氏菌分离株进行鉴定,结果A群4株、B群210株、C_1群61株、C_2群109株、D_1群119株、E群182株和F群7株.这一结果与用常规O血清进行的平行试验的鉴定结果一致.同时,这组单抗与172株非沙门氏菌分离菌株不反应.说明这组单抗可以取代常规O单因子血清和A-F群O多价血清用于沙门氏菌的分群鉴定。     

O139, 142, 26混合血清型大肠杆菌的O-抗原基因簇的破译

应用鸟枪法扩增了一株从水肿病病死猪肠系膜淋巴结分离到的O混合血清型(O139,142,26)大肠杆菌的O-抗原基因,测序结果显示扩增的O-抗原基因长度为11 771 bp。通过生物信息学的方法对其结构进行分析,发现其具有10个开放阅读框架及功能基因种类。经与发表的大肠杆菌O139、O26和O142的O-抗原基因序列及O-抗原糖基链的结构进行比对,进化树分析,跨膜蛋白的结构分析以及对乳糖前体(Glc)添加乙酰基的机制分析,结果表明,该O混合血清型大肠杆菌的O-抗原基因与大肠杆菌O139的O-抗原基因进化关系最近。     

Functional Genomics of the Aeromonas salmonicida Lipopolysaccharide O-Antigen and A-Layer from Typical and Atypical Strains

The A. salmonicida A450 LPS O-antigen, encoded by the wb_salmo gene cluster, is exported through an ABC-2 transporter-dependent pathway. It represents the first example of an O-antigen LPS polysaccharide with three different monosaccharides in their repeating unit assembled by this pathway. Until now, only repeating units with one or two different monosaccharides have been described. Functional genomic analysis of this wb_salmo region is mostly in agreement with the LPS O-antigen structure of acetylated l-rhamnose (Rha), d-glucose (Glc), and 2-amino-2-deoxy-d-mannose (ManN). Between genes of the wb_salmo we found the genes responsible for the biosynthesis and assembly of the S-layer (named A-layer in these strains). Through comparative genomic analysis and in-frame deletions of some of the genes, we concluded that all the A. salmonicida typical and atypical strains, other than A. salmonicida subsp. pectinolytica strains, shared the same wb_salmo and presence of A-layer. A. salmonicida subsp. pectinolytica strains lack wb_salmo and A-layer, two major virulence factors, and this could be the reason they are the only ones not found as fish pathogens.     

重庆市部分地区鸭源大肠杆菌的O抗原血清型及耐药性

从重庆市5个区、县的部分规模化鸭场收集以心包炎、肝周炎及腹膜炎为主要病理变化的病死鸭,无菌采取其心血和肝脏后接种,分离出30株细菌,经细菌的形态特性和生化特性分析,鉴定为大肠杆菌.该试验对分离的大肠杆菌进行了O抗原单价血清型鉴定试验及药敏试验.结果表明:30株分离菌中有23株定型分属于11种血清型,其中以O78,O93,O92和O21为优势血清型(共占46.67%).30株分离菌对21种抗生素的耐药率高于50%,其中耐受7种药物以上的有28株,占93.3%,耐受10种药物以上的有23株,占76.6%,表明重庆地区部分养鸭场鸭源大肠杆菌的耐药性严重.     

致仔猪腹泻大肠埃希菌的分离及耐药性分析

为调查江苏省泰州地区引起仔猪腹泻的主要病原,采集腹泻仔猪的肛拭子样品共70份,利用MA琼脂平板共分离得到136株细菌。鉴定结果表明,其中含大肠埃希菌119株、沙门氏菌5株、志贺菌4株、阪崎肠杆菌8株。致病性试验确定其中有81株细菌为致病性大肠埃希菌,对其进行O抗原血清型鉴定,有36株分离菌被定型,分属于6种血清型,以O₇₈和O₁₀₁为优势血清型。进一步对分离得到的大肠埃希菌进行肠毒素基因检测,结果表明,这些大肠埃希菌中包含ST1+ST2型20株、LT1+ST2型44株、ST2型17株,共3种产肠毒素类型。药敏试验结果显示,超过75%的菌株对头孢他啶、阿米卡星和氧氟沙星表现为敏感,而对常用的四环素、头孢呋辛、卡那霉素、多西环素等呈现耐药性,且存在严重的多药耐药现象。研究结果可为泰州地区仔猪腹泻的预防和治疗提供参考依据。     

鸭源致病性大肠杆菌O抗原与毒力基因检测及药敏试验

【目的】探究荣昌、大足和隆昌三地鸭大肠杆菌分离株的O抗原、毒力基因及耐药性。【方法】将2014年—2021年鸭病料中分离得到的107株细菌在无菌条件下接种于麦康凯培养基中划线进行培养纯化,通过16S rDNA基因扩增测序和生化试验进行细菌鉴定,采用PCR技术对O抗原和16种毒力基因进行检测,采用Kirby-Bauer纸片扩散法进行药敏试验。【结果】107株分离株鉴定为大肠杆菌;O抗原鉴定试验鉴定出9种O抗原,其中优势抗原为O78(37.00%)、O7(25.00%),O121和O145(均为15.00%),并检测到5株O78+O145和O7+O145融合株;共检测出11种毒力因子,其中强致病性毒力基因有Tsh基因(检出率为25.23%)、fyuA基因(检出率为31.78%)、estB基因(检出率为31.78%)、Vat基因(检出率为2.80%)、iucA基因(检出率为44.56%)。3种毒力基因ompA、yijP和ibeB的携带率最高,分别为100.00%、96.26%和85.98%;药敏试验结果表明分离株对氨基糖苷类药物、米诺环素和多黏菌素最为敏感,对大环内酯类药物和克林霉素耐药,分...