Profiling of Bacterial Communities of Hospital Wastewater Reveals Clinically Relevant Genera and Antimicrobial Resistance Genes

In Mexico, hospital wastewater (HWW) is a source of chemical and microbiological contamination, and it is released into the municipal sewage system without prior treatment. This water may contain pathogenic bacteria and antimicrobial resistance genes, which represent a risk to Public Health and the...

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Main Authors: Clemente Cruz-Cruz, Javier Gaytán-Cervantes, Carolina González-Torres, Andres Emmanuel Nolasco-Rojas, Miguel Ángel Loyola-Cruz, Laura Delgado-Balbuena, Josué Delgado-Balbuena, Marianela Paredes-Mendoza, María Concepción Tamayo-Ordóñez, Yahaira de Jesús Tamayo-Ordoñez, Emilio Mariano Durán-Manuel, Araceli Rojas-Bernabé, Carlos Alberto Jiménez-Zamarripa, Oscar Sosa-Hernández, Omar Agni García-Hernández, Esther Ocharan-Hernández, Paola Berenice Zárate-Segura, Elizabeth González-Terreros, Daniel Alejandro Ramírez-Villanueva, Claudia Camelia Calzada-Mendoza, Juan Manuel Bello-López
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Microorganisms
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Online Access:https://www.mdpi.com/2076-2607/13/6/1316
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Summary:In Mexico, hospital wastewater (HWW) is a source of chemical and microbiological contamination, and it is released into the municipal sewage system without prior treatment. This water may contain pathogenic bacteria and antimicrobial resistance genes, which represent a risk to Public Health and the environment. So far, there are no studies that analyse this problem comprehensively, relating bacterial population structures, chemical contaminants, and seasonality. The aim of this work was to seasonally characterise the bacterial communities of HWW, including clinically relevant bacteria and resistance genes in Hospital Juárez de México (HJM), and to evaluate the impact of physicochemical factors on their composition. A one-year observational, cross-sectional study was conducted at five HWW discharge points of HJM. Fourteen physicochemical parameters were determined by using standard methodologies, and statistical differences between discharges and seasons were evaluated. Bacterial communities were analysed by targeted amplicon sequencing of the V3-V4 region of the <i>16S rRNA</i> gene. In addition, the presence of eight antimicrobial resistance genes of local epidemiological importance was assessed. Data were analysed using alpha and beta diversity indices, principal component analysis, and multivariate statistical tests. HWW showed high taxonomic diversity, with Proteobacteria, Firmicutes, and Bacteroidetes standing out. Clinically relevant bacteria were identified in 73.3% of the analyses, with <i>Enterobacter</i> and <i>Escherichia-Shigella</i> predominating. Total and dissolved solids, temperature, nitrate, and pH significantly influenced the bacterial composition of HWW. Seven out of the eight genes evaluated were identified, with <i>bla<sub>KPC</sub></i>, <i>bla<sub>OXA-40</sub></i>, and <i>mcr-1</i> being the most frequent, showing significant seasonal differences. This study underlines the microbiological and chemical complexity of HWW, highlighting the impact of clinically relevant bacteria and antimicrobial resistance genes on Public Health. The findings emphasise the need to implement hospital waste management programmes and ideally specific treatment plants to minimise the associated risks and protect the environment and human health.
ISSN:2076-2607