Soupé-Gilbert Marie-Estelle, Bierque Emilie, Geroult Sophie, Teurlai Magali, Goarant Cyrille
Institut Pasteur International Network, Institut Pasteur in New Caledonia, Leptospirosis Research and Expertise Unit, Nouméa Cedex, New Caledonia.
Institut Pasteur International Network, Institut Pasteur in New Caledonia, Epidemiology and Infectious Research and Expertise Unit, Nouméa Cedex, New Caledonia.
Am J Trop Med Hyg. 2017 Oct;97(4):1088-1093. doi: 10.4269/ajtmh.17-0114. Epub 2017 Jul 19.
Rodents are the main reservoir animals of leptospirosis. In this study, we characterized and quantified the urinary excretion dynamics of by infected with 2 × 10 virulent serogroup Ballum. Each micturition was collected separately in metabolic cages, at 12 time points from 7 to 117 days post-infection (dpi). We detected in all urine samples collected (up to 8 per time point per mouse) proving that excretion is continuous with ca. 90% live Ballum, revealed by viability quantitative polymerase chain reaction. Microscopic visualization by Live/Dead fluorescence confirmed this high proportion of live bacteria and demonstrated that Ballum are excreted, at least partly, as bacterial aggregates. We observed two distinct phases in the excretion dynamics, first an increase in concentration shed in the urine between 7 and 63 dpi followed by a plateau phase from 63 dpi onward, with up to 3 × 10 per mL of urine. These two phases seem to correspond to progressive colonization of renal tubules first, then to stable cell survival and maintenance in kidneys. Therefore, chronically infected adult mice are able to contaminate the environment via urine at each micturition event throughout their lifetime. Because excretion reached its maximum 2 months after infection, older rodents have a greater risk of contaminating their surrounding environment.
啮齿动物是钩端螺旋体病的主要储存宿主动物。在本研究中，我们对感染2×10强毒巴豆油钩端螺旋体血清群的小鼠尿液排泄动态进行了表征和定量分析。在感染后7至117天的12个时间点，在代谢笼中分别收集每次排尿。我们在所有收集的尿液样本中均检测到（每只小鼠每个时间点最多8份），通过活菌定量聚合酶链反应显示，约90%为活的巴豆油钩端螺旋体，这证明钩端螺旋体的排泄是持续的。通过活/死荧光显微镜观察证实了活细菌的高比例，并表明巴豆油钩端螺旋体至少部分以细菌聚集体的形式排出。我们在排泄动态中观察到两个不同阶段，首先是感染后7至63天尿液中钩端螺旋体浓度增加，随后从63天起进入平台期，每毫升尿液中钩端螺旋体数量高达3×10。这两个阶段似乎首先对应于肾小管的渐进性定植，然后对应于肾脏中稳定的细胞存活和维持。因此，慢性感染的成年小鼠在其一生中的每次排尿事件中都能够通过尿液污染环境。由于钩端螺旋体排泄在感染后2个月达到最大值，年龄较大的啮齿动物污染其周围环境的风险更大。
