Ehrlichia canis is an intracellular parasitic bacterium and arthropod-borne pathogen that receives growing attention, because it leads to increasing morbidity and mortality in animals. It does so by causing canine monocytotropic ehrlichiosis (CME). Infected canines may lack obvious clinical signs and stay in chronic stage. Herein we report a rapid screening method based on PCR assay combined with quartz crystal microbalance (QCM) to design a DNA sensor for detecting E. canis in early stages of infection. The test relies on DNA amplification of target nucleotide sequences via PCR followed by detecting DNA-DNA hybridization using QCM. The approach did not result in any cross-hybridization toward other blood bacteria or parasites in dogs, such as Anaplasma platys, Babesia canis and Trypanosoma spp, but turned out selective for the target species. The limit of detection of QCM was as low as 4.1 × 109 molecules/μl of 289 bp E. canis PCR products corresponding to 22 copy numbers/μl of E. canis. Furthermore, the technique is also simple, does not require complicated equipment and can in principle be reused.

中文翻译：

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基于QCM的犬埃立克体PCR扩增产物快速检测

犬埃立克体是一种细胞内寄生细菌和节肢动物传播的病原体，受到越来越多的关注，因为它会导致动物的发病率和死亡率增加。它通过引起犬单核细胞埃立克体病（CME）来实现。受感染的犬科动物可能缺乏明显的临床症状并停留在慢性期。在此，我们报告了一种基于 PCR 测定结合石英晶体微量天平 (QCM) 的快速筛选方法，以设计用于检测感染早期犬大肠杆菌的 DNA 传感器。该测试依赖于通过 PCR 对目标核苷酸序列进行 DNA 扩增，然后使用 QCM 检测 DNA-DNA 杂交。该方法并未导致与狗体内的其他血液细菌或寄生虫（例如扁形无形体、犬巴贝斯虫和锥虫属）发生任何交叉杂交，但结果证明对目标物种具有选择性。QCM 的检测限低至 4.1 × 109 分子/μl 289 bp 犬大肠杆菌 PCR 产物，对应于 22 个拷贝数/μl 犬大肠杆菌。此外，该技术也简单，不需要复杂的设备，原则上可以重复使用。