小肠结肠炎耶尔森菌研究概况

小肠结肠炎耶尔森菌（Yersinia enterocolitica,简称Y．e）是自20世纪80年代以来引起国际上广泛注意的一种人畜共染病原细菌,广泛分布于自然界,已从人、动物、土壤、水和多种食品中分离出来。是能在冷藏温度下生长的少数肠道致病菌之一,全球由该菌引起的食源性疾病爆发已有数十起。该菌虽早在20世纪30年代已被发现,但直至20世纪60年代才逐渐引起国外微生物学、临床医学和流行病学家们的广泛注意,随着其重新分类和免疫学、分子生物学技术的发展,对Y．e菌的研究更进了一步,现将其综述如下。     

小肠结肠炎耶尔森氏菌依温毒性的研究

本文报告了来自不同国家和地区的人和动物的80株小肠结肠炎耶尔森氏菌的自凝性和血清抵抗性,并与前文报道的依钙性和毒力质粒对比。带毒力质粒的菌株均37℃阳性和25℃阴性,而无毒力质粒的菌株37℃和25℃均阴性。从而指出,带毒力的小肠结肠炎耶尔森氏菌有温度依赖的特性。同时证实,62株地方分离株均为毒力株,具有致病性。本文采用的自凝性和血清抵抗性试验方法具可靠、经济、快速和应用广泛等优点。     

小肠结肠炎耶尔森氏菌血清群的研究II．我国小肠结肠炎耶尔森氏菌分群菌株的筛选和参考菌株的建立

从我国收集到新分离的小肠结肠炎耶尔森氏菌1120株,经检定符合本菌特征的74 7株(占66．7％),并筛选出其形态、培养特征及生化特性典型的有335株,分成36个不同血清群,并分别找出各群代表株制出抗血清。试验结果证明,用本套菌株制备的群血清,灵敏性和特异性效价都优于国外引进的参考菌株制备的抗血清。通过实际使用,对国内新分离菌株检定能提高定群率2—3％。     

小肠结肠炎耶尔耶尔森氏菌血清群的研究：Ⅱ.我国小肠...

Since 1980, we have collected 1120 strains of Yersinia enterocolitica, from the different parts of China. These strains have been obtained from various sources in man, animals and natural environment accompanied by their clinical or ecological information of Yersinia enterocolitica. The results of our tests have shown that the 747 strains have exhibited the clinical morphological and biochemical characteristics of Yersinia enterocolitica. Through comparing under the same conditions, out of the 747 strains 335 have been selected out with better antigenicity and have been produced antisera from their representative strains. This set of antisera is very satisfactory for its potency and specificity. This set of antisera is ready to supply and have good efficacy and application facilitated for control strains on identifying strains and their epidemiologic observation.     

小肠结肠炎耶尔森氏菌血清群的研究I．“不能定群”菌株抗原性的研究

应用凝集素吸收试验和间接血凝试验,检定国内新分离的耶氏菌血清学试验中,有28株菌同现使用的51种(O：抗原因子为 1(1、2a、3)、2(2a、2b,3)、3、{．32、4．33、5、5．27、6·30、 6-31、 7·8、 8、 9、 lO、 l 0(k1)、 11·23、 11·2{、 l 2·25、 l 2·26、 13-7、 14、 15、l 6、1 6·29、17、1 8、t9·8、20、2l、22、25·3 5、28、35、36、37、38、39、40、41．42、qi．43、4 4、44·45、46、47、48、{9·5l、50·5l、52、52·53、52·5{、55、5 7)参考耶氏菌分群血清 均不呈凝集阳性反应,从中选出8株代表株进行抗原性试验。根据抗原性试验的分析证实,这些代表菌株之间抗原性是不同的,其菌号命名为Bc(1 413)、Bc(88)、Bc(89)、Bc(12)、Bc(18)、Bc(66)、Bc(777)、Bc(F37),并表明与51种群参考菌株的抗原也不相同,初步确认的8林菌属不同。抗原的新血清群菌株。     

粪便标本小肠结肠炎耶尔森菌筛检方法的比较

目的 比较分离培养法、反转录‒聚合酶链反应法对腹泻粪便中小肠结肠炎耶尔森菌的检测情况。方法 在2016年6月至2017年6月临床收治的腹泻患者中选取368例,均使用分离培养法、反转录‒聚合酶链反应法对其粪便中的小肠结肠炎耶尔森菌展开检验,对比分析两种方法的检验结果。结果 反转录‒聚合酶链反应法阳性率为77.17%,比分离培养法的51.09%高,差异有统计学意义（P＜0.05）;反转录‒聚合酶链反应法致病菌株检出率为83.10%,高于分离培养法的59.57%,差异有统计学意义（P＜0.05）。结论 对腹泻患者粪便标本中的小肠结肠炎耶尔森菌检测时,相较于分离培养法,反转录‒聚合酶链反应法阳性检出率更高,可使小肠结肠炎耶尔森菌性腹泻诊断准确率提升。     

致病性耶尔森菌强毒力岛的结构和功能研究进展

耶尔森菌属中鼠疫耶尔森菌,假结核耶尔森菌和小肠结肠炎耶尔森菌与人类致病关系密切,其鼠毒力是由染色体上存在的强毒力岛（HPI）决定,本文综述了由3种致病性耶尔森菌形成的2个HPI进化系Yen HPI和Yps HPI的结构和功能的研究进展。     

小肠结肠炎耶尔森菌对多粘菌素B的压力应答

【背景】小肠结肠炎耶尔森菌(Yersinia enterocolitica)是重要的人畜共患食源性病原菌。由于其生存环境与传染性生活方式,小肠结肠炎耶尔森菌暴露在各种生存压力中,而胞膜压力应答能力对维持其环境耐受性和毒力发挥着重要作用。【目的】探究小肠结肠炎耶尔森菌在胞膜压力应答中的调节机制。【方法】通过使用多粘菌素B破坏小肠结肠炎耶尔森菌细胞膜的稳定性,并从生长能力、运动能力、生物被膜形成能力以及相关基因表达的变化探讨Rcs (Regulator of Capsule Synthesis)系统对多粘菌素B产生的胞膜压力的应答。【结果】多粘菌素B引起的细胞胞膜压力抑制了小肠结肠炎耶尔森菌的运动和生物被膜形成能力;而阻断Rcs信号途径后,小肠结肠炎耶尔森菌的运动和生物被膜形成能力有所恢复。对flhC、hmsS、hmsT等关键下游表型基因的表达水平的分析结果表明Rcs双组分系统对由多粘菌素B诱导的胞膜压力作出响应,通过感知胞膜胁迫向胞内传递信号,积极地调控细菌增强对抗菌肽的抗性。【结论】明确了Rcs双组分系统在响应多粘菌素B压力胁迫中的特异性调控作用,加深了对小肠结肠炎耶尔森菌环境应答机制...     

鼠疫耶尔森氏菌基因转录调控的研究进展

细菌基因转录调控是多种调控机制中研究最为广泛的一种模式。复杂而精细的基因转录调控网络有助于细菌应答外界环境压力,在病原菌致病与传播中均发挥着关键作用。本文以鼠疫耶尔森氏菌基因转录调控的相关研究进展为基础展开论述,重点阐述细菌的转录调控机制、转录调控的研究策略及鼠疫菌致病与传播中转录调控的作用,以期为深入研究鼠疫菌致病与传播中的基因转录调控分子机制提供新思路。     

鼠疫耶尔森氏菌质粒上重要毒力相关基因的克隆与表达

鼠疫耶尔森氏菌含有3种质粒pMT1、pPCP1和pCD1,这3种质粒编码鼠疫耶尔森氏菌的多种重要毒力因子。首先通过生物信息学技术选定了18种可能重要的毒力相关基因作为拟克隆和表达的目的基因。通过：PCR技术、TA克隆技术、双酶切技术获得目的片段。这些目的片段再分别克隆入原核表达载体pET32a中,构建了一系列重组表达质粒,其中12个重要的毒力相关基因在原核表达载体pET32a中有稳定的高效表达,表达量占细菌总蛋白的20％～40％。实验结果为进一步研究质粒编码的毒力因子的结构与功能,及其作为新型疫苗选择的可能性奠定了基础。     

Investigation of virulence genes in clinical isolates of Yersinia enterocolitica

In this study, we aimed to investigate the distribution of virulence genes in clinical isolates of pathogenic Yersinia enterocolitica. Two thousand six hundred stool samples were collected from 2600 patients with diarrhea, and were tested using the culture method and real-time PCR. Then, all isolates of pathogenic Y. enterocolitica cultured from the culture method were examined for virulence genes (inv, ail, ystA, ystB, ystC, yadA, virF) by PCR and for the presence of plasmid by four phenotypic tests. As a result, 160 pathogenic strains were successfully detected by the culture method, including bio/serotype 1A/unknown (4), 1B/unknown (8), 2/O:9 (39), 2/unknown (7), 3/O:3 (22), 3/unknown (6), 4/O:3 (55), 4/unknown (10) and 5/unknown (9). The positive rate of virulence genes tested in 160 isolates was inv (100%), ail (94%), ystA (93%), ystB (7.5%), ystC (5%), yadA (89%) and virF (82%) while the phenotypic test included autoagglutination (87%), binding of crystal violet (89%), calcium-dependent growth (74%) and Congo red absorption (78%), respectively. Finally, we found that not all pathogenic Y. enterocolitica necessarily carry all traditional virulence genes in both chromosomes and plasmids to cause illness. Perhaps, some of them, lacking some traditional virulence genes, contain other unknown virulence markers that interact with each other and play an important role in the diverse pathogenesis of pathogenic Y. enterocolitica.     

Pathogenicity of Yersinia enterocolitica biotype 1A

Yersinia enterocolitica strains of biotype 1A lack the known virulence determinants of strains in other categories, including the Yersinia virulence plasmid (pYV), and several chromosomal markers of pathogenicity. For this reason, and also because Y. enterocolitica strains of biotype 1A are frequently isolated from the environment or asymptomatic individuals, these bacteria are often assumed to be avirulent. On the other hand, there is a considerable body of clinical, epidemiological and experimental evidence to indicate that at least some strains of Y. enterocolitica biotype 1A are able to cause gastrointestinal symptoms which resemble those caused by pYV-bearing strains. The availability of a number of experimental systems, including cell culture and animal models of infection, provides an opportunity to identify and characterise the essential virulence determinants of biotype 1A strains.     

Effects of Yersinia enterocolitica on bone marrow cells proliferation in mice

Intraperitoneal (i.p.) infection of mice with virulent Yersinia enterocolitica, that possess the virulence plasmid encoding calcium requirement, caused a significant reduction in the number of nucleated cells per femur, but increased significantly the ratio of both mitosis and in vitro colony-forming units (CFU) to marrow cells. A plasmid-less, isogenic avirulent derivative did not cause such differential effects on marrow cellularity and mitosis ratio. Thus, increase of granulocyte and mononuclear phagocyte progenitor cells by Y. enterocolitica was associated with virulence plasmid presence.     

The serodiagnosis of human infections with Yersinia enterocolitica and Yersinia pseudotuberculosis

The techniques of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting were evaluated for the serodiagnosis of human infections with Yersinia enterocolitica and Yersinia pseudotuberculosis. Lipopolysaccharide (LPS) was prepared from strains comprising four serogroups of Y. enterocolitica and five serogroups of Y. pseudotuberculosis, tested against 200 sera submitted to the Laboratory of Enteric Pathogens for routine serodiagnosis, and shown to contain antibodies to Yersinia LPS by agglutination. Forty four sera were found to contain antibodies that bound to one of the LPS preparations used in the immunoassay. Thirty five of the sera contained antibodies to the LPS of Y. enterocolitica O3, whilst three contained antibodies to the LPS of Y. enterocolitica O5, 27 and Y. enterocolitica O9 LPS respectively. Two sera had antibodies to the LPS of Y. pseudotuberculosis II and a single serum contained antibodies to Y. pseudotuberculosis IV. The SDS-PAGE-immunoblotting procedure described proved to be a reliable procedure for the serodiagnosis of infections with Y. enterocolitica and Y. pseudotuberculosis.     

Involvement of the virulence gene products of Yersinia enterocolitica in the immune response of infected mice

The virulence of Yersinia enterocolitica is known to be highly dependent on its virulence plasmid. However, it remains unclear whether the virulence plasmid is engaged also in the induction of cell-mediated immunity that is essential for protective immunity in the host. In this study, we have compared the induction of type 1 helper T cell immunity against Y. enterocolitica using a virulent strain (P+) harboring the pYV plasmid and an avirulent strain (P-) harboring no pYV. Spleen cells from both groups of mice immunized with 1/10 LD50 of P+ strain and those with 1/10 LD50 of P- strain produced a high level of gamma interferon (IFN-gamma) upon stimulation with heat-killed bacteria, and CD4+ T cells were exclusively responsible for IFN-gamma production. When crude Yersinia outer proteins (Yops) were used for antigenic stimulation, IFN-gamma response of immune spleen cells against crude Yops was observed only in mice immunized with P+ strain. Flowcytometric analysis revealed a significant level of increase in IFN-gamma-producing CD8+ T cells as well as the increase in IFN-gamma-producing CD4+ T cells against crude Yops. These results suggest that the virulence plasmid of Y. enterocolitica is involved in the induction of Th1-type of possibly protective T cells in infected mice.     

Proper expression of the O-antigen of lipopolysaccharide is essential for the virulence of Yersinia enterocolitica O:8 in experimental oral infection of rabbits

The O-antigen of lipopolysaccharide (LPS) is required for virulence in Yersinia enterocolitica serotype O:8. Here we evaluated the importance of controlling the O-antigen biosynthesis using an in vivo rabbit model of infection. Y. enterocolitica O:8 wild-type strain was compared to three mutants differing in the O-antigen phenotype: (i) the rough strain completely devoid of the O-antigen, (ii) the wzy strain that lacks the O-antigen polymerase (Wzy protein) and expresses LPS with only one repeat unit, and (iii) the wzz strain that lacks the O-antigen chain length determinant (Wzz protein) and expresses LPS without modal distribution of O-antigen chain lengths. The most attenuated strain was the wzz mutant. The wzz bacteria were cleared from the tissues by day 30, the blood parameters were least dramatic and histologically only immunomorphological findings were seen. The level of attenuation of the rough and the wzy strain bacteria was between the wild-type and the wzz strain. Wild-type bacteria were highly resistant to killing by polymorphonuclear leukocytes, the wzz strain bacteria were most sensitive and the rough and wzy strain bacteria were intermediate resistant. These results clearly demonstrated that the presence of O-antigen on the bacterial surface is not alone sufficient for full virulence, but also there is a requirement for its controlled chain length.     

Characterization of IS1541-like elements in Yersinia enterocolitica and Yersinia pseudotuberculosis

We characterized Yersinia enterocolitica and Yersinia pseudotuberculosis insertion sequences related to insertion sequence 1541, recently identified in Yersinia pestis. For each of the two species, two insertion sequence copies were cloned and sequenced. Genetic elements from Y. pseudotuberculosis were almost identical to insertion sequence 1541, whereas these from Y. enterocolitica were less related. Phylogenetic analysis of the putative transposases encoded by insertion sequences from the three pathogenic members of the genus Yersinia showed that they clustered with those encoded by Escherichia coli and Salmonella enterica elements belonging to the insertion sequence 200/insertion sequence 605 group. Insertion sequences originating from Y. pestis and Y. pseudotuberculosis constitute a monophyletic lineage distinct from that of Y. enterocolitica.     

Chromosome-mediated resistance of Yersinia enterocolitica serotype O9 to intracellular killing by mouse peritoneal macrophages

Abstract The survival of Yersinia enterocolitica serotype O9 within mouse peritoneal macrophages was investigated. To evaluate the role of the virulence plasmid in the resistance to intracellular killing, an isogenic pair of virulent (plasmid-bearing) and avirulent (plasmid-less) O9 strains was used. The virulent strain was able to express plasmid-encoded outer membrane proteins and to colonize the Peyer's patches of orally infected mice. When mice were infected intraperitoneally, both strains were recovered at similar rates and over the same time from the peritoneal cavity. When in vitro assays were performed, both strains showed similar resistance to intracellular killing by monolayers of resident and inflammatory peritoneal macrophages. Previous opsonization of bacteria did not modify their survival within macrophage monolayers. We concluded that serotype O9 strains display a chromosome-mediated resistance to intracellular killing by mouse peritoneal macrophages. Moreover, macrophage resistance does not seem to be of importance for virulence of serotype O9 strains in mice.