Department of Civil and Environmental Engineering, Yonsei University, Yonsei-ro 50, Seodaemun-gu, Seoul, South Korea.
Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ, 08544, USA.
Microb Ecol. 2019 Oct;78(3):677-687. doi: 10.1007/s00248-019-01348-0. Epub 2019 Mar 23.
Asian dust (AD) events have received significant attention due to their adverse effects on ecosystems and human health. However, detailed information about airborne pathogens associated with AD events is limited. This study monitored airborne bacterial communities and identified AD-specific bacteria and the potential hazards associated with these bacteria during AD events. Over a 33-month period, 40 air samples were collected under normal atmospheric conditions (non-AD events; n = 34) and during AD events (n = 6). The airborne bacterial communities in the air samples collected during non-AD events (non-AD sample) and AD events (AD sample) were evaluated using both culture-dependent and culture-independent methods. The bacterial diversity increased significantly, along with the 16S rRNA gene copy number, in AD samples (p < 0.05) and was positively correlated with PM concentration. High throughput sequencing of the 16S rRNA gene revealed that the relative abundance of the phylum Firmicutes increased substantially in AD samples (44.3 ± 5.0%) compared with non-AD samples (27.8 ± 4.3%). Within the phylum Firmicutes, AD samples included a greater abundance of Bacillus species (almost 23.8%) than non-AD samples (almost 13.3%). Both culture-dependent and culture-independent methods detected common predominant species closely related to Bacillus cereus during AD events. Subsequent multilocus sequence typing (MLST) and enterotoxin gene assays confirmed the presence of virulence factors in B. cereus isolates from AD samples. Furthermore, the abundance of bceT, encoding enterotoxin in B. cereus, was significantly higher in AD samples (p < 0.05). The systematic characterization of airborne bacterial communities in AD samples in this study suggests that B. cereus pose risks to public health.
亚洲沙尘（AD）事件因其对生态系统和人类健康的不利影响而受到广泛关注。然而，有关与 AD 事件相关的空气传播病原体的详细信息有限。本研究监测了空气中的细菌群落，并在 AD 事件期间鉴定了与 AD 事件相关的特定细菌和这些细菌的潜在危害。在 33 个月的时间里，在正常大气条件下（非 AD 事件；n=34）和 AD 事件期间（n=6）共收集了 40 个空气样本。使用培养依赖和培养独立的方法评估了在非 AD 事件（非 AD 样本）和 AD 事件（AD 样本）中收集的空气样本中的空气细菌群落。AD 样本中的细菌多样性（p<0.05）和 16S rRNA 基因拷贝数显著增加，并且与 PM 浓度呈正相关。16S rRNA 基因高通量测序显示，与非 AD 样本（27.8±4.3%）相比，AD 样本中厚壁菌门的相对丰度显著增加（44.3±5.0%）。在厚壁菌门中，AD 样本中 Bacillus 属的丰度（几乎 23.8%）明显高于非 AD 样本（几乎 13.3%）。培养依赖和培养独立的方法都在 AD 事件期间检测到与 Bacillus cereus 密切相关的常见优势种。随后的多位点序列分型（MLST）和肠毒素基因检测证实了 AD 样本中 B. cereus 分离株存在毒力因子。此外，AD 样本中 bceT（编码 B. cereus 肠毒素）的丰度明显更高（p<0.05）。本研究对 AD 样本中空气传播细菌群落的系统特征分析表明，B. cereus 对公众健康构成威胁。
