Short-term exposure to benzalkonium chloride in bacteria from activated sludge alters the community diversity and the antibiotic resistance profile
artículo original
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2021-12Autor
Chacón Jiménez, Luz María
Arias Andrés, María de Jesús
Mena Torres, Freylan
Rivera Montero, Luis César
Hernández Gómez, Lorena
Achí Araya, María Rosario
García Santamaría, Fernando
Rojas Jiménez, Keilor Osvaldo
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The continuous introduction of cleaning products containing benzalkonium chloride (BAC) from household discharges can mold the microbial
communities in wastewater treatment plants (WWTPs) in a way still poorly understood. In this study, we performed an in vitro exposure of
activated sludge from a WWTP in Costa Rica to BAC, quantified the changes in intI1, sul2, and qacE/qacEΔ1 gene profiles, and determined
alterations in the bacterial community composition. The analysis of the qPCR data revealed elevated charges of antibiotic resistance genes in
the microbial community; after BAC’s exposure, a significant increase in the qacE/qacEΔ1 gene, which is related to ammonium quaternary
resistance, was observed. The 16S rRNA gene sequences’ analysis showed pronounced variations in the structure of the bacterial communities, including reduction of the alpha diversity values and an increase of the relative abundance of Alphaproteobacteria, particularly of
Rhodospseudomonas and Rhodobacter. We confirmed that the microbial communities presented high resilience to BAC at the mg/mL
concentration, probably due to constant exposure to this pollutant. They also presented antibiotic resistance-related genes with similar
mechanisms to tolerate this substance. These mechanisms should be explored more thoroughly, especially in the context of high use of
disinfectant.