Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland.
J Clin Microbiol. 2013 Jan;51(1):169-76. doi: 10.1128/JCM.01955-12. Epub 2012 Oct 31.
Neoehrlichiosis caused by "Candidatus Neoehrlichia mikurensis" is an emerging zoonotic disease. In total, six patients have been described in Europe, with the first case detected in 2007. In addition, seven patients from China were described in a report published in October 2012. In 2009, we diagnosed the first human case of "Ca. Neoehrlichia mikurensis" infection in the Zurich area (Switzerland). Here, we report two additional human cases from the same region, which were identified by broad-range 16S rRNA gene PCR. Both patients were immunocompromised and presented with similar clinical syndromes, including fever, malaise, and weight loss. A diagnostic multiplex real-time PCR was developed for specific detection of "Ca. Neoehrlichia mikurensis" infections. The assay is based on the signature sequence of a 280-bp fragment of the "Ca. Neoehrlichia mikurensis" 16S rRNA gene and incorporates a "Ca. Neoehrlichia mikurensis" species, a "Ca. Neoehrlichia" genus, and an Anaplasmataceae family probe for simultaneous screening. The analytical sensitivity was determined to be below five copies of the "Ca. Neoehrlichia mikurensis" 16S rRNA gene. Our results show that the assay is suitable for the direct detection of "Ca. Neoehrlichia mikurensis" DNA in clinical samples from, for example, blood and bone marrow. In addition, it allows for monitoring treatment response during antibiotic therapy. Using the same assay, DNA extracts from 1,916 ticks collected in four forests in close proximity to the patients' residences (<3 km) were screened. At all sampling sites, the minimal prevalence of "Ca. Neoehrlichia mikurensis" was between 3.5 to 8% in pools of either nymphs, males, or females, showing a strong geographic association between the three patients and the assumed vector.
由“候选新立克次体”引起的新立克次体病是一种新兴的人畜共患病。在欧洲，总共描述了 6 例病例，首例病例于 2007 年发现。此外，2012 年 10 月发表的一份报告中描述了来自中国的 7 例病例。2009 年，我们在苏黎世地区（瑞士）诊断出首例人类“候选新立克次体”感染病例。在这里，我们报告了来自同一地区的另外两例人类病例，这些病例是通过广谱 16S rRNA 基因 PCR 鉴定的。两名患者均免疫功能低下，表现出相似的临床综合征，包括发热、乏力和体重减轻。开发了一种用于特异性检测“候选新立克次体”感染的诊断多重实时 PCR。该检测基于“候选新立克次体”16S rRNA 基因 280bp 片段的特征序列，并包含“候选新立克次体”、“新立克次体属”和“立克次体科”探针，用于同时筛查。分析灵敏度确定为低于“候选新立克次体”16S rRNA 基因的 5 个拷贝。我们的结果表明，该检测适用于直接检测来自血液和骨髓等临床样本中的“候选新立克次体”DNA。此外，它还允许在抗生素治疗期间监测治疗反应。使用相同的检测方法，从距离患者住所<3 公里的四个森林中采集的 1916 只蜱的 DNA 提取物进行了筛查。在所有采样地点，幼蜱、雄蜱或雌蜱的“候选新立克次体”最小流行率在 3.5%至 8%之间，这表明三名患者与假设的媒介之间存在强烈的地理关联。
