两株非典型烟曲霉临床株抗真菌药物敏感性和形态异常相关分子机制研究

目的：比较两株白色不产孢烟曲霉临床株（A1j和A2j）的抗真菌药物敏感性及形态异常产孢基因与Af293的差异性。方法：采用改良的琼脂稀释药敏实验方法检测A1j和A2j与模式对照菌Af293对伏立康唑(VRC)、 伊曲康唑(ITC)和两性霉素B(AMB)的敏感性。采用PCR和RT-PCR的方法对A1j和A2j产孢相关基因brlA和wetA进行检测。结果：抗真菌试剂可抑制Af293、A2j和A1j的生长,差异无统计学意义。产孢诱导6h后,Af293中brlA基因转录水平显著上升,而A1j和A2j中对应的产孢基因转录水平无明显变化。brlA基因测序结果示A1j菌株无突变,A2j存在TCCT碱基缺失。结论：非典型烟曲霉A1j和A2j与标准株Af293在抗真菌药物敏感性方面没有差异,A2j存在形态异常产孢基因brlA突变。     

PCR检测深部致病真菌感染的研究

目的探讨PCR在可疑深部真菌感染临床标本检测中的应用。方法对60份临床标本分别进行传统真菌培养以及真菌通用引物PCR和三重PCR检测。结果真菌培养阳性共19份，其中白念珠菌10份、烟曲霉2份、新生隐球菌2份、其他菌株5份（包括光滑念珠菌2份、热带念珠菌2份、克柔念珠菌1份）；真菌通用PCR检测共有21份阳性，经三重PCR检测共有15份阳性，分别为白念珠菌10份、烟曲霉3份、新生隐球菌2份。PCR方法与传统培养方法相比，检出率差异无统计学意义。结论PCR检测可疑深部真菌感染临床标本快速简便，稳定性好，敏感性和特异性均较理想，适合临床实验室常规使用。     

Small-Bowel Infarction From Disseminated Aspergillosis

INTRODUCTION: Despite the use of new, effective drugs, the disseminated invasive aspergillosis often remains lethal in neutropenic patients. Diagnosis is difficult because early symptoms are nonspecific. New tools could help in diagnosis and lead to early surgery when needed.METHODS: A neutropenic patient developed an acute abdomen. CT findings were a diffuse, small-bowel distention with a thickened, distal, ileum wall. Emergency surgery was performed with resection and immediate anastomosis of the distal ileum. Pathology of the small bowel showed a wall necrosis and invasion by Aspergillus fumigatus.RESULTS: The postoperative course was uneventful except for persisting diarrhea secondary to a coexistent infection with Clostridium difficile. Aspergillus antigene in serum was positive, whereas neither pulmonary nor central nervous system aspergillosis was observed on CT scan.CONCLUSIONS: This diagnosis should be considered when neutropenic patients show abdominal pain and distention with fever. Repetition of Aspergillus antigenemia, search for others aspergillosis localizations, CT scan, and colonoscopy with biopsies should be performed until diagnosis allows the administration of early antifungal therapy.     

Aspergillus fumigatus pacemaker lead endocarditis: a case report and review of the literature

The diagnosis of fungal endocarditis requires a high index of clinical suspicion. Rarely, pacemaker implantation may be a risk factor for the development of fungal endocarditis. A 71-year-old man with a history of multiple transvenous pacemaker manipulations and fever of an uncertain source is described. A diagnosis of culture-negative pacemaker endocarditis was established only after repeat transthoracic echocardiography. Amphotericin B was instituted; however, the patient developed a cerebral infarct and died. Postmortem examination demonstrated Aspergillus fumigatus within a large pacemaker lead thrombus, tricuspid and aortic valve vegetations, and septic pulmonary and renal emboli. The present report describes the clinical and pathological features of a rare case of Aspergillus fumigatus pacemaker lead endocarditis and suggests that serial echocardiograms may be effective in the early detection of pacemaker lead vegetations. The diagnostic features and therapeutic management of pacemaker lead endocarditis are reviewed.     

Aspergillus thyroiditis: first antemortem case diagnosed by fine‐needle aspiration culture in a pediatric stem cell transplant patient

Aspergillus thyroiditis (AT) has historically been considered a postmortem diagnosis in immunocompromised patients; most have disseminated disease. This report summarizes the clinical challenge of diagnosing AT. It also highlights the value of the early use of thyroid fine‐needle aspiration culture and the need for a high index of suspicion to reach the final diagnosis before disease dissemination.     

Clinical significance of Aspergillus fungaemia in patients with haematological malignancies and invasive aspergillosis

The clinical significance of Aspergillus fungaemia in the setting of a deep-seated aspergillosis has not been clearly established. Among 107 microbiologically documented Aspergillus infections in patients with haematological diseases observed over a 17-year period, blood cultures grew Aspergillus species from 10 cases. Aspergillus fungaemia was documented in 9 out of 89 (10.1%) patients with pulmonary aspergillosis at a median of 5 d from the onset of clinical signs of infection, and in one patient with central venous catheter focal infection. Five (50%) patients died as a result of fungal infection a median of 12 d (range 4--48) from the documentation of Aspergillus fungaemia. A comparison between cases of invasive aspergillosis with or without fungaemia showed that fungaemic patients were similar to those without positive blood cultures regarding clinical presentation, risk factors, clinical course and outcome. The diagnostic role of Aspergillus fungaemia in the setting of a deep-seated infection is limited because blood cultures become positive when a microbiological or clinical diagnosis of aspergillosis has already been performed. Aspergillus fungaemia does not necessarily seem to be correlated with a disseminated infection or a poorer prognosis.     

烟曲霉刺激后内皮细胞膜受体C型植物血凝素-1及Toll样受体的表达

目的 研究内皮细胞接触烟曲霉后表面受体树突状细胞相关性C型植物血凝素-1(Dectin-1)及Toll样受体2(TLR2)的表达变化,探讨其在免疫过程中的作用.方法 烟曲霉与人脐静脉内皮细胞共孵育,分不同时间(1、2、4及6 h)点收集细胞,流式细胞仪检测Dectin-1受体及TLR2表达的变化;提取细胞总蛋白,应用Western blot法检测细胞受体蛋白表达水平的变化;应用间接免疫荧光染色法观察各受体在细胞内外的分布情况.结果 (1)静息状态下,内皮细胞膜表面可见Dectin-1及TLR2表达,其平均荧光强度值分别为45和13.经烟曲霉刺激后,TLR2表达逐渐下降至18,Dectin-1表达先升高后下降,接触2 h后平均荧光强度值升至35,6 h后又降至18;(2)Western blot 法检测结果显示,内皮细胞经烟曲霉刺激后2 h Dectin-1蛋白表达最明显,4 h次之,6 h最低;而TLR2在各时间点均无明显变化;(3)共聚焦显微镜下可见部分烟曲霉出芽孢子和菌丝进入内皮细胞,细胞膜、孢子和菌丝表面均可见 Dectin-1表达;TLR2仅在细胞表面表达.结论 烟曲霉感染时,内皮细胞可表达Dectin-1及TLR2,这对识别是否为烟曲霉感染有重要价值.

Abstract：

Objective To observe the changes of TLR-2, Dectin-1 expression on endothelial cells,and to explore their role in the immune response after contact with Aspergillus fumigatus. Methods Aspergillus fumigatus and human umbilical vein endothelial cells were co-incubated. Cells were collected respectively after incubation for 0 h, 1 h, 2 h, 4 h and 6 h. TLR2 and Dectin-1 receptor expressions were detected by flow cytometry, and their protein was measured by Western blot. The distribution of the receptors in the cells were observed by immunofluorescence. Result TLR2 and Dectin-1 were expressed on the endothelial cell surface in quiescent condition. The mean fluorescence intensity of TLR2 on endothelial cells decreased from 45 to 13 stimulation by Aspergillus fumigatus, but the mean fluorescence intensity of Dectin-1increased from 13 to 35 in the first 2 hours and then decreased. By Western blot, the electrophoresis strip of Dectin-1 was most bright in 2 hours after contact with the fungus, and then decreased 4 and 6 hours. TLR2did not change significantly. Dectin-1 with fluorescent labeling was seen in spores and hyphae as well as in the cell membrane under confocal microscope. TLR2 was detected only on cell surface. Conclusion TLR2and Dectin-1 were expressed by endothelial cells, and may be useful in the identification of Aspergillus fumigatus.