Leptospira sp. from water ways in Iowa

Leptospirosis is a neglected zoonotic disease in the world. Leptospirosis is rarely recognized in U.S. and is associated with individuals living in economically disadvantaged urban inner-city environments, recreational exposures, and occupational exposures to infected animals. Transmission to humans and animals occurs by direct contact with reservoir animals or indirect exposure through contact with environmental water or moist soil contaminated with pathogenic Leptospira spp. Leptospira can be maintained in soils and waters for weeks to months. The leptospirosis epidemiology is complex and is a paradigm of a One Health disease. To understand the diversity of strains that occupy water environments in Central Iowa and the evolutionary dynamics of Leptospira, we isolated strains and conducted whole-genome sequencing of 82 Leptospira isolates in this study. The study was conducted in Iowa, a midwestern U.S. state during the summer from June to September, 2021. Water samples were processed for culture and lipL32 rt-PCR. Recovered isolates were classified using whole-genome sequencing, serotyping with reference antisera. A total of 105 water samples were collected in nine counties in Iowa state, 5/105 (4.7%) were positive by lipL32 rt-PCR. Molecular typing indicated that three isolates were L. montravelensis, two were L. kemananensis, five were L. bourretii, six were L. bouyouniensis, six were L. bandadrabouensis, one was L. abararensis, two were L. chreensis, four were L. bourretti, six were L. terpstrae, one was L. yanagawae, two were L. ellinghausenii and twenty-two were possible new species; the remaining twenty-five comprised mixed species. We were able separate one L. interrogans from one mixed species.

莱姆病是全球范围内被忽视的人畜共患病。在美国，莱姆病鲜少被识别，其感染与居住在经济条件较差的都市内城区环境的人群、娱乐活动暴露以及接触感染动物的职业暴露有关。人类和动物的传播途径包括与储存宿主直接接触或通过接触被致病性莱姆螺旋体（Leptospira spp.）污染的环境水体或湿润土壤的间接暴露。莱姆螺旋体能够在土壤和水中维持数周到数月。莱姆病的流行病学复杂，是“健康一体化”疾病的典范。为了理解占据中部爱荷华州水域环境的菌株多样性以及莱姆螺旋体的进化动态，本研究中我们从82株莱姆螺旋体分离株中进行了全基因组测序。该研究于2021年6月至9月在美国中西部州爱荷华州夏季进行。对采集于爱荷华州九个县区的105份水样进行了培养和lipL32实时荧光定量PCR检测。通过全基因组测序、血清分型与参考抗血清进行分型，对恢复的分离株进行了分类。共收集了105份水样，其中5份（4.7%）通过lipL32实时荧光定量PCR检测呈阳性。分子分型结果显示，三株为L. montravelensis，两株为L. kemananensis，五株为L. bourretii，六株为L. bouyouniensis，六株为L. bandadrabouensis，一株为L. abararensis，两株为L. chreensis，四株为L. bourretti，六株为L. terpstrae，一株为L. yanagawae，两株为L. ellinghausenii，二十二株可能为新的物种；剩余的二十五株为混合物种。我们成功地将一株L. interrogans从一株混合物种中分离出来。