ANTIBIOTICS TRAVEL THROUGH THE AQUATIC WORLD: A REVIEW SUMMARISES TEN YEARS OF RESEARCH

Used every day to treat both people and animals, antibiotics have played a decisive role in improving public health. Yet once administered, part of these substances inevitably ends up in the environment. Through urban wastewater, sewage or residues from livestock farming, they can reach rivers, lakes, seas and groundwater, where they may persist for long periods and interact with aquatic ecosystems. This issue is the focus of a review carried out by researchers at the Istituto Zooprofilattico Sperimentale dell’Abruzzo e del Molise (IZSAM), published in the journal Science of the Total Environment.

The review examined 6,305 concentration measurements from 101 studies conducted over the past decade across six continents and 76 countries, outlining a global picture of antibiotic contamination in aquatic environments. In total, 142 molecules were considered, including degradation products, belonging to 15 classes of antibiotics, from penicillins and tetracyclines to macrolides and quinolones. The findings show that antibiotic residues are widespread across all continents, though their concentrations and distribution vary greatly between regions.

"Our analysis gathered and compared data produced by more than ten years of research - says Roberta Rosato, researcher at the Food Chemistry and Drug Residues Unit, IZSAM - providing an overview of antibiotic concentrations in water and the differences between regions and types of aquatic environments. In particular, developing countries showed higher concentrations, a consequence of limited or absent national policies aimed at tackling water pollution from emerging contaminants, and of low awareness regarding the responsible use of antibiotics and wastewater management. However, much remains to be done. Many areas are still poorly studied, and the limited monitoring of certain molecules seems linked to the lack of reference materials and analytical methods."

The presence of antibiotics in aquatic ecosystems is not only an indicator of pollution but can also trigger profound consequences. Even at low concentrations, these substances can alter the balance of microbial communities and favour the selection of resistant bacteria, which find in the environment ideal conditions to spread their resistance genes. Through food chains and contact with humans or animals, this mechanism may contribute to the global spread of antimicrobial resistance, one of the most serious public health threats of our time.

"Understanding where, how much and in what form these substances accumulate is essential to develop effective prevention strategies - Rosato continues - The spread of antibiotics in water is a silent yet concrete threat, closely linking the health of ecosystems to that of animals and humans. This is why research must increasingly focus on more sensitive monitoring methods and on targeted, integrated solutions that bring together healthcare, environmental protection and production chains in a One Health perspective."