Sérgio A. Ramos ¹ Edivaldo C. Sousa Junior ² Oscar Victor Cardenas Alegria ³ Elianne Da Silva Vieira ³ Sandro Silva ⁴ Ana Cecilia R. Cruz ⁴ Fabiano C. Moreira ¹ Adriana R. Nunes ^3*

• ¹ Oncology Research Center, João de Barros Barreto Hospital, Federal University of Pará, Belém, PA, Brazil
• ² Laboratory of Leishmaniasis, Parasitology Section, Evandro Chagas Institute, Ananindeua, PA, Brazil
• ³ Laboratory of Genomics and Bioinformatics, Center of Genomics and Systems Biology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil., Belém, Pará, Brazil
• ⁴ Arbovirology and Hemorrhagic Fevers Section, Evandro Chagas Institute, Ananindeua, PA, Brazil

The advancement of antimicrobial resistance is a significant public health issue today. With the spread of resistant bacterial strains in water resources, especially in urban sewage, metagenomic studies enable the investigation of the microbial composition and resistance genes present in these locations. This study characterized the bacterial community and antibiotic resistance genes in a sewage system that receives effluents from various sources through metagenomics. One liter of surface water was collected at four points of a sewage channel, and after filtration, the total DNA was extracted and then sequenced on an NGS platform (Illumina® NextSeq). The sequenced data were trimmed, and the microbiome was predicted using the Kraken software, while the resistome was analyzed on the CARD webserver. All ecological and statistical analyses were performed using the RStudio tool. The complete metagenome results showed a community with high diversity at the beginning and more restricted diversity at the end of the sampling, with a predominance of the phyla Bacteroidetes, Actinobacteria, Firmicutes, and Proteobacteria. Most species were considered pathogenic, with an emphasis on those belonging to the Enterobacteriaceae family. It was possible to identify bacterial groups of different threat levels to human health according to a report by the U.S. Centers for Disease Control and Prevention. The resistome analysis predominantly revealed genes that confer resistance to multiple drugs, followed by aminoglycosides and macrolides, with efflux pumps and drug inactivation being the most prevalent resistance mechanisms. This work was pioneering in characterizing resistance in a sanitary environment in the Amazon region and reinforces that sanitation measures for urban sewage are necessary to prevent the advancement of antibiotic resistance and the contamination of water resources, as evidenced by the process of eutrophication.