Department of Environment and Health, Tianjin Institute of Environmental & Operational Medicine, Key Laboratory of Risk Assessment and Control for Environment & Food Safety, Tianjin 300050, China.
Department of Environment and Health, Tianjin Institute of Environmental & Operational Medicine, Key Laboratory of Risk Assessment and Control for Environment & Food Safety, Tianjin 300050, China.
J Hazard Mater. 2023 Oct 5;459:132300. doi: 10.1016/j.jhazmat.2023.132300. Epub 2023 Aug 14.
Groundwater is a vital source of drinking water for Tibetans. Antibiotic resistance genes (ARGs) and bacterial communities in groundwater on the Tibetan Plateau remain unclear. Furthermore, the characterization of their differences between high-altitude and low-altitude groundwater is still unrevealed. Herein, 32 groundwater samples were collected on the plateau, and intra- and extracellular ARGs (iARGs and eARGs), and bacterial communities were characterised through qPCR assays to 19 ARGs and 16S rRNA sequencing. It showed top four abundant intra- and extracellular last-resort ARGs (LARGs) were bla, mcr-1, vanA, and vanB, whereas dominant common ARGs (CARGs) were tetA and ermB, respectively. CARGs had higher abundances than LARGs, and iARGs were more frequently detected than eARGs. Proteobacteria, an invasive resident phylum, and Firmicutes dominated eDNA release. Network analysis revealed all observed LARGs co-occurred with pathogenic and non-pathogenic bacteria. Community diversity was significantly associated with longitude and elevation, while nitrate correlated with ARGs. Comparative analysis demonstrated eARG frequencies and abundances were higher at high altitudes than at low altitudes. Additionally, Acinetobacter and Pseudomonas specifically dominated at high altitudes. This study reveals the widespread prevalence of ARGs, particularly LARGs, in groundwater on the less-disturbed Tibetan Plateau and underlines the potential risks associated with the LARG-carrying bacteria. ENVIRONMENTAL IMPLICATION: Antibiotic resistance genes (ARGs), which are defined as emerging environmental contaminants, are becoming a global concern due to their ability to confer antibiotic resistance to pathogens. Our findings highlight the prevalence of ARGs, particularly LARGs, in groundwater on the Tibetan Plateau, and the possibility that naturally-occurring pathogenic and non-pathogenic bacteria carry multiple LARGs. In addition, we further reveal differences in the distribution of ARGs and bacterial community between high-altitude and low-altitude groundwater. Collectively, our findings offer an important insight into the potential public risks related to groundwater on the Tibetan Plateau.
地下水是西藏人重要的饮用水源。青藏高原地下水的抗生素耐药基因（ARGs）和细菌群落仍不清楚。此外，高海拔和低海拔地下水之间的差异特征尚未揭示。在此，从高原上采集了 32 个地下水样本，并通过 qPCR 检测到 19 个 ARG 和 16S rRNA 测序来对其进行了胞内和胞外 ARGs（iARGs 和 eARGs）和细菌群落的特征分析。结果表明，丰度最高的四种胞内和胞外最后保留 ARGs（LARGs）分别是 bla、mcr-1、vanA 和 vanB，而主要的常见 ARGs（CARGs）分别是 tetA 和 ermB。CARGs 的丰度高于 LARGs，并且 iARGs 的检出频率高于 eARGs。变形菌门，一种入侵的常驻门，和厚壁菌门主导着 eDNA 的释放。网络分析表明，所有观察到的 LARGs 与致病性和非致病性细菌共同发生。群落多样性与经度和海拔显著相关，而硝酸盐与 ARGs 相关。比较分析表明，高海拔地区的 eARG 频率和丰度高于低海拔地区。此外，不动杆菌属和假单胞菌属在高海拔地区特别占优势。本研究揭示了在受干扰较小的青藏高原地下水以及潜在的 LARG 携带细菌相关风险中，ARGs，特别是 LARGs 的广泛流行。环境意义：抗生素耐药基因（ARGs）被定义为新兴的环境污染物，由于其赋予病原体抗生素耐药性的能力，因此成为全球关注的焦点。我们的研究结果强调了 ARGs，特别是 LARGs，在青藏高原地下水以及天然存在的致病性和非致病性细菌携带多种 LARGs的可能性。此外，我们进一步揭示了高海拔和低海拔地下水之间 ARG 和细菌群落分布的差异。总的来说，我们的研究结果为青藏高原地下水可能存在的公共风险提供了重要的见解。
