Research on the critical pathogens Klebsiella pneumoniae and Aspergillus fumigatus within the One Health sector is vital due to the interconnected nature of human, animal, and environmental health in the development and spread of antimicrobial resistance (AMR). These pathogens pose a significant global health threat and studying them within this comprehensive framework provides several key benefits. Furthermore, data on the prevalence of these pathogens in veterinary health, the food chain and environmental health is lacking in Belgium.
; Firstly, both pathogens are known for their increasing resistance to critical drugs. K. pneumoniae is highly resistant to carbapenems and third-generation cephalosporins, while A. fumigatus has developed resistance to azole antifungals, which are crucial for treating A. fumigatus. This resistance complicates treatment options, making infections harder to manage, and heightens the urgency to develop new strategies for combating these pathogens. Secondly, these pathogens affect not only human health but also animals and the environment. K. pneumoniae can be found in hospitals, animal farms, and wastewater, while A. fumigatus is widely present in the environment, with hotspots in green waste management environments and plant bulb waste. Research within a One Health approach allows us to understand how these different sectors contribute to the evolution and transmission of AMR. By looking at the broader context, we can identify key points of intervention that might be missed in siloed approaches. Another critical aspect is understanding the transmission pathways between sectors. K. pneumoniae may spread from livestock to humans via the food chain or through environmental contamination, such as wastewater, while A. fumigatus can develop resistance due to the widespread use of antifungals in agriculture and infect the susceptible population. This cross-sectoral research helps to map out how these pathogens move between humans, animals, and the environment, revealing opportunities for more effective containment strategies, protecting both public and animal health.
; In the first main part of the thesis, research on the prevalence of (antimicrobial-resistant) K. pneumoniae in the different sectors of the One Health framework was performed. Using whole genome sequencing (WGS), we elucidated the resistance mechanisms responsible for phenotypical resistance, and we elucidated clusters within and across sectors of the One Health framework. In the second part of the thesis, we focused on identifying the prevalence of azole-resistant A. fumigatus in the environmental and animal sector. Sequencing was performed to elucidate the resistance mechanisms, which proved to be mainly from the environmental route of resistance selection. We identified some shortcomings in our research and included these in the project proposal for the upcoming National Action Plan on Antimicrobial Resistance (NAP AMR 2025-2029).
; In summary, studying A. fumigatus and K. pneumoniae within the One Health framework is crucial for developing comprehensive solutions to combat AMR. This approach not only addresses the immediate health risks but also helps prevent future outbreaks of resistant infections by recognizing the interconnectedness of human, animal, and environmental health.