2020年07月10日

    近日团队梁志梳博士后等在珠江口典型区域生物气溶胶及其健康风险等方面取得最新的研究进展，研究成果以“Pollution profiles of antibiotic resistance genes associated with airborne opportunistic pathogens from typical area, Pearl River Estuary and their exposure risk to human”为题发表在《Environment International, 2020, 143: 105934》上。

    为了揭示近海岸人类活动对海洋和陆地生物气溶胶的影响，我们选取了海洋和陆地过渡地带珠江河口作为我们研究的典型区域，考察了该地区生物气溶胶的分布特征及其人体健康风险。我们发现珠江河口约70%生物气溶胶粒径<4.7 µm，一般情况下细菌>真菌，春季>夏季。气象条件(温度和相对湿度等)会影响生物气溶的分布。此外，海洋、水产养殖和工业活动（印染和啤酒厂）等对生物气溶胶的组成和丰度也有显著的影响。生物多样性研究发现Firmicutes，Proteobacteria，Actinobacteria和Ascomycota是生物气溶胶中最主要的微生物，其中Firmicutes可能主要来源于海洋。此外，在生物气溶胶中还检测出大量的致病细菌(Burkholderia-Paraburkholderia, Staphylococcus 和 Acinetobacter)和真菌（Alternaria, Penicillium 和 Cladosporium）。在21种检测到的ARGs中四环素抗性基因tetA丰度最高，其次是氨基糖苷类抗性基因。海鲜交易市场ARGs含量要远远高于其他地区，说明水产养殖和交易过程可能会产生大量的耐药生物气溶胶。此外，我们还检测出大量的可移动遗传元件（MGE），揭示生物气溶胶中的ARGs可能通过基因水平转移传播。相关性分析表明空气中致病菌菌群与ARGs显著相关，Escherichia-Shigella, Burkholderia-Paraburkholderia, Enterococcus, Clostridiaceae 和Bacteroides 可能是ARGs的宿主。最后，我们基于每日呼吸摄入生物气溶胶剂量以及每日直接吸入致病菌和耐药基因的量，对生物气溶胶暴露风险进行了评估，发现尽管可培养微生物气溶胶的非致癌风险可以忽略，但是每日呼吸摄入致病菌和耐药基因的量高达108 copies d-1。因此，我们认为在往后河口等特殊环境监测和风险评估过程中应当关注致病生物气溶胶和耐药生物气溶胶的污染问题。

    论文英文摘要

    To reveal the selective pressures of near-shore human activities on marine and continental bioaerosols, the pollution profile and potential exposure risk of airborne pathogens and antibiotic-resistance genes (ARGs) in Pearl River Estuaries (113.52 oE, 22.69 oN), a transitional zone between marine and continental environments, were fully explored. The results showed that the total bacteria among bioaerosols varied largely with average pollution levels of 1.86×105 and 4.35×104 cfu m-3 in spring and summer, respectively, and were high than those of airborne fungi. The predominant aerodynamic diameters of bioaerosols were in respirable size range (<4.7µm), and the microbes communities’ diversity and abundance varied significantly. Besides, many opportunistic pathogenic bacteria (Burkholderia-Paraburkholderia, Staphylococcus and Acinetobacter) and fungi (Alternaria, Penicillium and Cladosporium) were dominant in bioaerosol samples. Of 21 ARGs subtypes detected, the tetracycline resistance gene tetA was the most abundant, followed by aminoglycoside resistance gene and mobile genetic elements. Correlation analysis revealed that the changes of pathogens community contributed significantly to the prevalence of ARGs in bioaerosol. Based on the average daily dose rates of microorganisms and human direct intake of ARGs, health risk of bioaerosols from the Pearl River Estuaries were also evaluated. In summary, the presence of opportunistic pathogens and diversity of ARGs strengthens the call to consider the bioaerosol in air quality monitoring and risk assessment in the future.

    本研究受到国家自然科学基金（U1901210, 41877363, 41807405），广东省自然科学基金（2019A1515010599），广州市科技计划项目（201704020185），广东省本土创新团队项目（2017BT01Z032）的资助。

    论文链接：https://doi.org/10.1016/j.envint.2020.105934