Study suggests microplastics in aquatic systems accumulate pathogenic bacteria resistant to antibiotics
A study by the Faculty of Science and Technology of the University of Coimbra (FCTUC) suggests that microplastics accumulate more bacteria resistant to antibiotics in natural substrates, such as sand, in aquatic systems (rivers).
This study, by Isabel Silva, a Ph.D. student in Biosciences at the Department of Life Sciences (DCV) at FCTUC, also reveals that the type of plastic influences the number and characteristics of bacteria that adhere to these particles.
«Recently, it was verified that the characteristics of these particles facilitate the establishment of a set of microorganisms with different characteristics from those established in other substrates. One of the concerns that arises is the possibility of these microorganisms including bacteria resistant to antibiotics, capable of causing serious infections (pathogenic bacteria)», emphasizes Isabel Silva.
During the investigation, it was possible to detect «potentially pathogenic bacteria included in the priority list of the World Health Organization (WHO), multiresistant, that is, resistant to three or more classes of different antibiotics, and with worrying virulence characteristics. Most of these bacteria were detected in microplastics exposed to the influence of wastewater discharges, demonstrating once again the contribution of these discharges to the evolution of the problem of resistance to antibiotics», observes the author.
However, she clarifies, «Wastewater treatment plants contribute significantly not only to reducing the number of antibiotic-resistant bacteria in the final effluents but also to reducing the number of microplastics that reach the receiving systems. But, unfortunately, the treatment processes available are not effective enough to eliminate the impact that we observed in this study», laments the student.
The results of this study, now published in the journal Environmental Pollution, show the great relevance of supporting measures that can mitigate the spread of antibiotic resistance. «New data were presented that identify wastewater discharges as determinants in modulating both the microbiological composition of microplastics and the resistance characteristics of these microorganisms», points out Isabel Silva.
In addition, he continues, “The fact that the type of microplastics alters the ability of these particles to transport pathogenic and multiresistant bacteria, may influence future choices regarding the use of different types of plastics. Ultimately, this study presents more evidence that points to the pressing need to reduce the use of plastic, namely microplastics, and to improve wastewater treatments in order to retain and eliminate these contaminants», he concludes.
The study was coordinated by Isabel Henriques, a professor at the DCV and researcher at the Center for Functional Ecology (CFE), and Marta Tacão, an assistant researcher at the Center for Environmental and Sea Studies at the University of Aveiro, with the participation of Elsa Rodrigues researcher at CFE.
The scientific article can be consulted here.
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