Microbial Communities' Characterization in Urban Recreational Surface Waters Using Next Generation Sequencing.

Microbial communities in surface waters used for recreational purposes are indicators of contamination and risk of contact with human pathogens. Hence, monitoring microbial communities in recreational waters is important for potential public health threats to humans. Such monitoring is rare in Colombia, even in its capital, Bogotá, the most populous city in the country. This city encompasses metropolitan and linear parks with recreational water bodies that are used frequently by the public, and the presence of pathogens can compromise the health of the citizens. Therefore, we examined the bacterial, and eukaryotic communities in urban recreational lakes (URL) in four metropolitan parks in Bogotá, Colombia. Samples from four metropolitan parks (Los Novios, Simon Bolivar, El Tunal, and Timiza) and one stream contaminated with sewage from a linear park (El Virrey) were collected. We used amplicon next-generation sequencing of the 16S-rRNA gene and 18S-rRNA gene to characterize microbial communities followed by bioinformatics analyses. In addition, general water quality parameters-pH, hardness, acidity, alkalinity, dissolved oxygen, and nitrites-were recorded using a commercial kit. Genera of pathogens, including Legionella, Pseudomonas, Mycobacterium, Candida, and Naegleria, were found in lake waters. The stream El Virrey was, however, the only surface water that showed an abundance of fecal bacteria, often associated with low oxygen concentrations. All water bodies showed a predominance of fungal phyla, except for the lake at Timiza. This lake showed the highest pH, and its ecological dynamics are likely different from other water bodies. Likewise, some URLs displayed a greater abundance of cyanobacteria, including toxin-producing species. Algal genera associated with eutrophication were predominant among primary producing microorganisms. This study shows for the first time the description of the bacterial and eukaryotic communities of some URLs and a stream in Bogotá. The URLs and the stream harbored various pathogens that might pose a risk to the citizen's health.