Microbiology and Pathogenesis Activity, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80521, USA.
Vector Borne Zoonotic Dis. 2011 Mar;11(3):197-200. doi: 10.1089/vbz.2010.0149. Epub 2010 Oct 6.
Borrelia burgdorferi, the bacterium that causes Lyme disease, is transmitted to a susceptible host by Ixodes spp. tick bites. However, there is uncertainty whether B. burgdorferi are shed from ticks by the fecal route. In this study, B. burgdorferi-infected ticks were fed on mice while confined to a certain area of the skin by a capsule. During and after feeding, tick feces were collected and placed in Barbour-Stoenner-Kelley (BSK)-II media for cultivation and in sterile water for polymerase chain reaction (PCR) analysis. Although none of the tested samples were culture positive for B. burgdorferi, all but one of the fecal DNA samples from infected ticks were PCR positive. These results indicated that B. burgdorferi were shed from feeding ticks during defecation and suggest that the spirochetes did not remain viable once exposed to the outside environment. This finding has important ramifications for investigators interpreting B. burgdorferi-specific PCR results when conducting tick transmission experiments.
伯氏疏螺旋体（引起莱姆病的细菌）通过硬蜱属的蜱叮咬传播给易感宿主。然而，伯氏疏螺旋体是否通过粪便途径从蜱中排出仍不确定。在这项研究中，将感染伯氏疏螺旋体的蜱限制在一个胶囊内的皮肤特定区域，让它们叮咬小鼠。在进食过程中和进食后，收集蜱的粪便，并将其放置在 Barbour-Stoenner-Kelley (BSK)-II 培养基中进行培养，以及在无菌水中进行聚合酶链反应（PCR）分析。尽管没有一个测试样本的培养结果呈伯氏疏螺旋体阳性，但所有来自感染蜱的粪便 DNA 样本中，除了一个样本外，其余均为 PCR 阳性。这些结果表明，伯氏疏螺旋体在排粪时从进食的蜱中排出，并表明螺旋体一旦暴露在外部环境中就不再具有活力。这一发现对解释蜱传播实验中伯氏疏螺旋体特异性 PCR 结果的研究人员具有重要意义。
