九龙江流域潜在病原菌污染分析

近年来,由于流域经济快速发展和城镇化进程加快等原因,九龙江水污染问题日趋严重.为全面认识九龙江流域病原菌的分布状况,应用16S rRNA基因-454焦磷酸测序技术测定九龙江支流西溪、北溪水体和沉积物中细菌16S rRNA基因V1~V3高变区,共获得204 216条高质量序列.通过与病原菌参考数据库对比分析发现,九龙江分布有68个潜在病原菌属,占序列总量的6.1%.其中梭菌属(Clostridium)、分支杆菌属(Mycobacterium)和鞘氨醇单胞菌属(Sphingomonas)在所有样品中都有检出,且丰度最高,分别占病原菌属序列总量的54.5%、5.9%和5.6%.在种水平上,九龙江分布有48种病原菌,占序列总量的0.76%.其中Afipia felis、Mycobacterium asiaticum、Clostridium baratii、Brucella melitensis和Delftia tsuruhatensis是丰度最高的5种病原菌,分别占病原菌种序列总量的48.9%、20.3%、8%、2.7%和1.7%.统计分析表明,九龙江水体中分布的病原菌种类数(属或种)显著高于沉积物中,且西溪水体检出的病原菌种类(属或种)和丰度最高,说明九龙江水体,尤其是西溪水体受病原菌污染的风险较高.此外,相关分析表明,九龙江水体中病原菌的种类数(属或种)和丰度与营养盐(氮、磷)有着显著的正相关关系,说明九龙江水体中分布的病原菌与沿岸的人类活动,如养殖业、污水排放等密切相关.因此,为保证流域的公共卫生安全,需进一步加强污染源清理整顿工作,开展水环境病原菌的实时监测.

Distribution of Potential Pathogenic Bacteria in the Jiulong River Watershed

Recently, the human activities including economic growth and urbanization posed serious environmental health risks to the Jiulong River Watershed (JRW). In order to gain a full understanding of the distribution of potential pathogenic bacteria (PPB) in this area, we used 16S rRNA amplicon pyrosequencing technology to investigate planktonic and benthic bacterial community in two main tributaries (North River, NR, and West River, WR) of the Jiulong River (JR). At the genus level, a total of 68 genera of PPB were identified in JR, which accounted for 6.1% of total gene sequences. Clostridium, Mycobacterium and Sphingomonas were three most dominant genera, which accounted for 54.5%, 5.9% and 5.6% of the total gene sequences respectively, and occurred in all samples. At the species level, a total of 48 species of PPB were identified in JR, which accounted for 0.76% of total gene sequences. Afipia felis, Mycobacterium asiaticum, Clostridium baratii, Brucella melitensis and Delftia tsuruhatensis were the five most dominant species, and accounted for 48.9%, 20.3%, 8%, 2.7% and 1.7%, respectively. Statistical analysis indicated that the number of taxa (species or genera) of PPB in JR water samples were significantly more than those from JR sediment samples. Moreover, WR water samples harbored the most abundant and diverse of PPB, suggesting that WR water might have a high potential risk for pathogen contamination. In addition, statistical analysis indicated that the diversity and abundance of PPB (species or genera) are significantly positively correlated with nutrient (nitrogen and phosphorus) concentrations, suggesting that human activities in the JRW such as sewage discharge from livestock and wastewater treatment facilities play important roles on affecting the distribution of PPB in JR. Therefore, in order to protect the public health, more efforts are needed to prevent water contamination, and conduct the real-time monitoring of PPB in JR.