Metagenomic Profiling Unveils the Microbial Composition of Urban River Tributaries: Impact of Human Activities on Water Quality. Metagenomic Profiling Unveils the Microbial Composition of Urban River Tributaries: Impact of Human Activities on Water Quality

Anthropogenic activities have a negative impact on aquatic environments and the organisms living in them. Aquatic ecosystems are widely used in multiple human activities. For this reason, multiple strategies have been implemented to evaluate the microbial presence, including studies related to the microbial ecology of these environments and New Generation Sequencing (NGS) analysis, which has gained popularity. In this study, we descriptively determined water quality by analyzing samples from four tributaries of the Bogotá River using physicochemical and microbiological methods, complemented by shotgun metagenomics. The results revealed the circulation of microbial communities, including bacteria associated with some genera reported to be important in bioremediation processes, as well as others with pathogenic potential. We found molecular markers of interest in health, such as those related to antimicrobial resistance (predominantly those associated with resistance to aminoglycoside, macrolide, fluoroquinolone, and tetracycline antibiotics, which are widely used in animal production systems). The panorama is worrisome in the final section of the affluents where they are more impacted by human communities, revealing the possible anthropic impact after passing through a city as populated as Bogotá D.C in Colombia. This study allowed us to obtain high-quality metagenome-assembled genomes for species such as Aliarcobacter cryaerophilus, Acinetobacter johnsonii, and Succinivibrio, which were characterized using a comparative genomic approach. We present the current state of the sampled points, obtaining basic information and providing a starting point for future research strategies and also to figure out the most proper treatment of aquatic environments in developing countries.

人类活动（Anthropogenic activities）对水生环境及其栖息生物具有负面影响。水生生态系统广泛应用于各类人类活动，为此学界已制定多种策略以评估微生物群落存在情况，包括相关环境微生物生态学研究，以及日益普及的新一代测序（New Generation Sequencing，NGS）分析。本研究采用理化与微生物学方法，结合鸟枪法宏基因组学（shotgun metagenomics），对波哥大河（Bogotá River）四条支流的水样展开分析，以描述性方式评估水质。结果显示，研究区域存在多种微生物群落，其中包含若干被报道在生物修复过程中发挥关键作用的菌属相关细菌，以及部分具有致病潜力的菌株。本研究检测到多类与健康相关的分子标志物，例如与抗菌药物耐药性（antimicrobial resistance）相关的标志物，其中以氨基糖苷类（aminoglycoside）、大环内酯类（macrolide）、氟喹诺酮类（fluoroquinolone）及四环素类（tetracycline）抗生素（该类抗生素广泛应用于畜禽养殖系统）耐药相关的标志物为主。在支流受人类聚居区影响更为显著的下游河段，该污染形势尤为严峻，这揭示了流经人口稠密的哥伦比亚波哥大哥伦比亚特区（Bogotá D.C.）后，人类活动对水环境的潜在负面影响。本研究成功获取了嗜冷阿里杆菌（Aliarcobacter cryaerophilus）、约翰逊不动杆菌（Acinetobacter johnsonii）及琥珀酸弧菌属（Succinivibrio）等物种的高质量宏基因组组装基因组（metagenome-assembled genomes），并通过比较基因组学方法（comparative genomic approach）对其进行了表征。本研究明确了各采样点的当前水环境状态，可为后续研究策略提供基础数据与切入点，同时也为发展中国家的水环境优化治理提供参考依据。