Insights into the environmental dimension of antibiotic resistance : a One Health perspective
(2024)
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- Abstract
- To address the current antibiotic resistance issue, a One Health holistic approach is needed. The “environmental” component of this concept is often neglected, as opposed to the health of humans and animals, which are extensively studied. However, the role of the environment in the transmission and dispersion of antibiotic resistance needs to be further investigated to gain insights into the problematic as a whole. Several potential entryways of antibiotic residues, antibiotic resistance genes (ARGs) and antibiotic resistant bacteria (ARB) for the environment have been identified. Among these, the use of antibiotics as plant protection products and the application of manure on agricultural fields were the focus of the present thesis. The first part of this work focused on clarifying the main actors involved in the use of antibiotics in plant agriculture worldwide and on extensively exploring the current knowledge regarding antibiotic resistance genetic determinants associated with the use of antibiotics against plant pathogenic bacteria (PPB). For this purpose, a world map compiling users and non-users of antibiotics was established, the first in its kind. In addition, the main mechanisms of resistance and the potential of spreading of these ARGs were brought to light, unravelling the presence of highly similar variants of a transposon carrying ARGs, both in human pathogens and in PPB, which suggests potential unknown routes of exchange between them. The second part of this thesis investigated the impact of antibiotic treatment of livestock animals on the bacterial populations present in their manure, or slurry, and the potential effects of manure spreading on soil bacterial populations, through the monitoring of their densities over time and by the isolation and genomic analyses of resident strains of Bacillus cereus sensu lato and Pseudomonas spp. Even though a clear influence of antibiotic treatment on manure or manure spreading on fields could not be observed with the techniques used in this work, ARB could be isolated in all environmental samples analysed, raising awareness regarding possible dissemination and transfer of resistance in the environment. Altogether, this work indicates that the environment should not be overlooked in the global antibiotic resistance issue and hints towards the introduction of an integrated surveillance of antibiotic resistance in the environment, notably through the monitoring of relevant indicator species and antibiotic residues in environmental samples, as well as metagenomic analyses of bacterial community dynamics under environmental antibiotic stresses.
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Verhaegen, M. (2024). Insights into the environmental dimension of antibiotic resistance : a One Health perspective. https://hdl.handle.net/2078.5/31710