提取程度及电泳上样量对布氏菌外膜蛋白电泳图谱恒定性的影响

由于难以从布氏菌的外膜蛋白中将干扰因素多糖成分去除到恒定水平的最低限度,迄今未能获得可用于分类的恒定的外膜蛋白电泳图谱。我们最大限度地提取出外膜蛋白及牢固附于其上的多糖成分;在电泳过程中又以超载的手段促使该二成分的相互作用达到综合平衡状态。由此可以消除不等程度多糖的干扰而产生的外膜蛋白电泳谱带的不恒定。为揭示了不同种布氏菌微孔蛋白热解聚前后电泳谱带变化规律及其所表现出的种的特异性奠定了基础。     

布氏菌致病因子的研究进展

布氏菌是引起人和动物布鲁菌病的病原体。这类兼性胞内寄生菌表达一系列的致病因子,包括脂多糖、外膜蛋白和Ⅳ型分泌系统等以保持其毒力。有些致病因子是侵袭宿主所必需的,有些致病因子对逃脱宿主免疫系统的清除是必需的,它们保证了布氏菌在胞内的生存和增殖,逃脱宿主免疫系统的攻击。了解其致病因子和作用机制可为疫苗研制提供依据,也可促使新的抗生素研制。现就布氏菌致病因子的研究进展予以综述。     

A rare case of seronegative culture--proven infection with Brucella suis

Brucellosis is a chronic infection produced by members of the Brucella family. Diagnosis of this condition requires either isolation of the organism in culture or positive serological tests.We describe a 27-year-old male admitted as a case of pyrexia of unknown origin (PUO), who tested negative for Brucella IgM ELISA test on preliminary evaluation but was subsequently diagnosed on the strength of positive blood and bone marrow cultures to be a case of brucellosis secondary to Brucella suis infection. In addition to highlighting the pathogenic potential of an unusual organism, this case demonstrates the unreliability of standard serological tests based on the Brucella melitensis antigen for infection with other species of Brucella.     

布鲁氏菌的分子生物学诊断技术

布鲁氏菌分型在布病的诊断和流行病学调查中发挥着重要作用。利用分子生物学技术可以快速、准确地鉴定布鲁氏菌。本文综述了布鲁氏菌分子生物学诊断技术特别是PCR及其衍生技术的研究进展,并对其优缺点进行了分析。     

Brucella endocarditis in prosthetic valves

Human brucellosis is a multiple organ disease that presents with fever and is most often transmitted via contaminated, unpasteurized goat milk and cheese. In chronic cases, focal complications (eg, spondylitis, neurobrucellosis and endocarditis) are frequently seen. Although the disease may be severely debilitating, the mortality rate is low. Fatal cases are often due to endocarditis. Because Brucella endocarditis is a rare complication (2% to 5%), therapeutic considerations are based on single-case experiences only. Therapy includes long-term antibiotic treatment using combinations of various antimicrobial drugs and surgical valve replacement when required. A case of Brucella endocarditis complicated by the infection of two valvular prostheses implanted after involvement of the mitral and aortic valve due to rheumatic fever is described. The patient was successfully treated by a medical and surgical approach. Therapeutic strategies in Brucella endocarditis are discussed in light of the current literature.     

Brucella endocardititis: clinical particularities and therapeutic modalities

Brucella infective endocarditis is an uncommon, but serious complication of brucellosis. The aortic valve is the most commonly affected cardiac valve. Due to characteristics of the infection, medical therapy alone is not sufficient in treating the disease and best results are obtained with surgery combination. We describe a case of Brucella endocarditis involving the aortic valve suspected in front of the clinical data and the results of serology, confirmed by the culture of the native valves. In association with the medical treatment, management valve replacement lead to a favorable medium-term evolution.     

布鲁菌S2感染后死亡的巨噬细胞启动T细胞应答的作用

目的研究布鲁菌S2感染死亡的巨噬细胞在启动细胞免疫应答中的作用。方法以布鲁菌S2株体外感染小鼠腹腔巨噬细胞,并以未感染的正常细胞作为对照,感染后1h用不含血清的RPMI1540培养基饥饿培养5d,待细胞完全死亡后与骨髓源性树突状细胞共培养24h后,ELISA法检测细胞上清中IL-12、TNF—α水平;同时将树突状细胞与淋巴结T细胞共培养,在共培养的不同时间点ELISA法检测培养上清中IFN-γ含量。结果正常死亡的巨噬细胞和S2株感染死亡的巨噬细胞与树突状细胞共培养后均可刺激树突状细胞分泌TNF—α,但S2株感染死亡组的TNF—α分泌水平明显高于正常死亡组（P〈0．05）,但不刺激IL-12分泌,且与T细胞共培养各时间点IFN-γ的分泌水平均高于对照组（P〈0．05）。结论感染布鲁菌S2株死亡的巨噬细胞可激活树突状细胞,并可使其提呈抗原、诱导T细胞产生IFN-γ。     

Expression of heme oxygenase-1 is associated with abortion caused by Brucella abortus infection in pregnant mice

Brucella abortus is a facultative intracellular pathogen that can survive inside macrophages and trophoblast giant (TG) cells, and the causative agent of brucellosis. In the present study, we found that expression of heme oxygenase-1 (HO-1) in TG cells is correlated with abortion induced by B. abortus infection in pregnant mice. Expression of HO-1 in the placenta was decreased by B. abortus infection and treatment with cobalt-protoporphyrin (Co-PP), which is known to up-regulate HO-1 expression, inhibited abortion due to the bacterial infection. In TG cells, treatment with Co-PP was shown to up-regulate HO-1, whereas its expression was decreased by B. abortus infection. Such down-regulation of HO-1 in the TG cells was enhanced by IFN-gamma treatment. HO-1 down-regulation in TG cells due to knockdown or IFN-gamma treatment served to induce cell death caused by B. abortus infection. These results suggest that down-regulation of HO-1 in TG cells due to B. abortus infection is an important event in infectious abortion.     

The BMEI0216 gene of Brucella melitensis is required for internalization in HeLa cells

Brucella is an intracellular facultative bacterium able to survive and multiply in professional and non-professional phagocytes. However, its adhesion and invasion mechanisms have not been elucidated yet. In this work, we assess the interruption of a BMEI0216 gene of Brucella melitensis, by using HeLa epithelial cells and murine macrophages for invasion and replication assays. The mutation did not affect survival or multiplication within macrophages. Likewise, invasion assays with HeLa cells revealed no differences at 30 and 45 min, whereas, at 1 and 2h, the infection ability of the mutant was drastically reduced. These results suggest that the BMEI0216 gene is required for B. melitensis internalization.