The Key Laboratory of Water and Air Pollution Control of Guangdong Province, South China Institute of Environmental Sciences, Ministry of Ecology and Environment of the People's Republic of China, Guangzhou, 510000, PR China.
Zhaoqing Municipal Ecology and Environment Bureau, Zhaoqing, 526060, PR China.
Environ Pollut. 2022 Nov 15;313:120101. doi: 10.1016/j.envpol.2022.120101. Epub 2022 Sep 2.
Antibiotic resistance genes (ARGs) are abundantly shed in feces. Thus, it is crucial to identify their host sources so that ARG pollution can be effectively mitigated and aquatic ecosystems can be properly conserved. Here, spatiotemporal variations and sources of ARGs in the Longjiang watershed of South China were investigated by linking them with microbial source tracker (MST) indicators. The most frequently detected ARGs (>90%) were sulI, sulII, bla, tetW, ermF, and the mobile element intI1. Spatial distribution analyses showed that tributaries contributed significantly more sulI, sulII, and ermF contamination to the Longjiang watershed than the main channel. MST indicator analysis revealed that the Longjiang watershed was contaminated mainly by human fecal pollution. Livestock- and poultry-associated fecal pollution significantly declined after the swine fever outbreak. The occurrence of most ARGs is largely explained by human fecal pollution. In contrast, pig fecal pollution might account for the prevalence of tetO. Moreover, combined human-pig fecal pollution contributed to the observed bla distribution in the Longjiang watershed. Subsequent analysis of the characteristics of MST markers disclosed that the relatively lower specificities of BacHum and Rum-2-Bac may lead to inaccurate results of tracking ARG pollution source. The present study determined spatiotemporal variations and ARG origins in the Longjiang watershed by combining MST markers. It also underscored the necessity of using multiple MST markers simultaneously to identify and characterize ARG pollution sources accurately.
抗生素耐药基因（ARGs）在粪便中大量释放。因此，确定其宿主来源至关重要，这样才能有效减轻 ARG 污染，保护水生态系统。本研究通过将微生物源追踪（MST）指标与抗生素耐药基因（ARGs）联系起来，调查了中国南方龙江流域的时空变化和 ARG 来源。检测到的最常见的 ARGs（>90%）是 sulI、sulII、bla、tetW、ermF 和移动元件 intI1。空间分布分析表明，与主河道相比，支流对龙江流域的 sulI、sulII 和 ermF 污染贡献更大。MST 指标分析表明，龙江流域主要受到人类粪便污染。猪瘟爆发后，与畜牧业相关的粪便污染显著减少。大多数 ARGs 的发生主要归因于人类粪便污染。相比之下，猪粪便污染可能是 tetO 流行的原因。此外，人猪粪便混合污染可能导致龙江流域 bla 的分布。随后对 MST 标记物特征的分析表明，BacHum 和 Rum-2-Bac 的特异性相对较低，可能导致追踪 ARG 污染来源的结果不准确。本研究通过 MST 标记物结合，确定了龙江流域的时空变化和 ARG 来源，并强调了同时使用多种 MST 标记物来准确识别和表征 ARG 污染来源的必要性。
