Seki Makoto, Iwamoto Reika, Hou Jianjian, Fujiyoshi So, Maruyama Fumito, Furusawa Yukihiro, Kagaya Shigehiro, Sakatoku Akihiro, Nakamura Shogo, Tanaka Daisuke
Graduate School of Science and Engineering, University of Toyama.
Center for the Planetary Health and Innovation Science (PHIS), The IDEC Institute, Hiroshima University.
Microbes Environ. 2025;40(1). doi: 10.1264/jsme2.ME24078.
Clostridium spp. are anaerobic, Gram-positive, spore-forming bacteria comprising more than 150 species, some of which are important pathogens of humans and animals. Members of this genus have been isolated from a number of environments, but are rarely found in the atmosphere. In the present study, we exami-ned culturable airborne Clostridium spp. and clarified their pathogenicity. We obtained 19 culturable Clostridium isolates from size-fractionated samples collected at a suburban site in Toyama, central Japan. Culturable Clostridium spp. were detected in particles larger than 1.1 μm, and the size distribution peaked at 2.1-3.3 μm, corresponding to the spore size of Clostridium spp. More Clostridium spp. were detected in coarse particles >2.1 μm not only by culture methods, but also by 16S rRNA gene amplicon sequencing. Whole-genome sequencing (WGS) identified seven Clostridium species, among which Clostridium perfringens was predominant. Moreover, WGS revealed that C. perfringens isolates harbored many virulence and antibiotic resistance genes with the potential to cause gas gangrene. The detection and characterization of potential airborne pathogens are crucial for preventing the spread of diseases caused by these pathogens. To the best of our knowledge, this is the first study to demonstrate that anaerobic Clostridium spp. may be transported under aerobic conditions in the atmosphere and pose potential risks to human health.
梭菌属是厌氧、革兰氏阳性、形成芽孢的细菌，包含150多个物种，其中一些是人和动物的重要病原体。该属成员已从多种环境中分离出来，但在大气中很少发现。在本研究中，我们检测了可培养的空气传播梭菌属细菌，并阐明了它们的致病性。我们从日本中部富山一个郊区站点采集的按大小分级的样本中获得了19株可培养的梭菌分离株。在大于1.1微米的颗粒中检测到了可培养的梭菌属细菌，其大小分布在2.1-3.3微米处达到峰值，这与梭菌属细菌的芽孢大小相对应。不仅通过培养方法，而且通过16S rRNA基因扩增子测序，在大于2.1微米的粗颗粒中检测到了更多的梭菌属细菌。全基因组测序（WGS）鉴定出了7种梭菌，其中产气荚膜梭菌占主导。此外，WGS显示产气荚膜梭菌分离株含有许多毒力和抗生素抗性基因，有可能导致气性坏疽。检测和鉴定潜在的空气传播病原体对于预防由这些病原体引起的疾病传播至关重要。据我们所知，这是第一项证明厌氧梭菌属细菌可能在有氧条件下在大气中传播并对人类健康构成潜在风险的研究。
