Understanding copper- and silver-based antimicrobials and their potential in space applications

Maertens Laurens


Matroule Jean-Yves, jean-yves.matroule@unamur.be

SCK•CEN Mentor

Van Houdt Rob
+32 14 33 27 28

SCK•CEN Co-mentor

Monsieurs Pieter
+32 14 33 21 08

Expert group


PhD started


Short project description

It is clear that crew health and safety need to be ensured during (long-term) space missions. To guarantee the health of the astronauts, several prevention, monitoring and mitigation measures are implemented by the space agencies to control microbial contamination (Novikova, 2004;Van Houdt and Leys, 2012;Van Houdt et al., 2012) and the development of improved spaceflight-suitable methods for microbiological monitoring, as well as contamination control and reduction is an important research area. One group of antimicrobials that are explored are metals, such as copper and silver, for which various studies indicated their potential (Boyce, 2016). However, bacterial resistance mechanism to these and other antimicrobials have been described repeatedly (Mijnendonckx et al., 2013a;Hobman and Crossman, 2015;Lawaree et al., 2016). Moreover, these resistance mechanisms are often strictly regulated, and currently, the main focus has been on the transcriptional network. Yet, recent research has shown the importance of post-transcriptional regulation via small regulatory RNAs (Vogel and Luisi, 2011;Papenfort and Vanderpool, 2015), a regulatory level which has been ignored so far when studying bacterial metal resistance. Nonetheless, it has been shown that the behavior of bacteria differs under space conditions with a central role for Hfq (Wilson et al., 2007), a RNA chaperone that interacts with those small regulatory RNAs. Therefore, the bacterial response to such metal-based antimicrobials needs to be thoroughly evaluated before possible implementation. Such tests are ideally performed on microorganisms isolated from space habitats, e.g. Cupriavidus metallidurans strains recently isolated from the ISS drinking water systems (Mijnendonckx et al., 2013b).


To main objective of this project is to study the response of bacteria to copper- and silver-based antimicrobials in the frame work of space applications. To dissect the problem, the focus will be on the metal ions, as many of the more complex compounds just ferry ions that are released and exert their action, and on Cupriavidus metallidurans strains isolated from actual contamination events that occurred in the ISS drinking water systems (Mijnendonckx et al., 2013b). Taking into account the role of Hfq during space flight (Wilson et al., 2007) and its altered gene expression after metal exposure (Monsieurs et al., 2011), a particular focus will be on post-transcriptional regulation via small regulatory RNAs, as this regulation level is barely studied in the context of copper and silver resistance. These data will support the assessment of metal-based antimicrobials for space applications and will scientifically underpin a recent ESA-approved science project on metal-based antimicrobials that is scheduled to be conducted onboard ISS (SCK•CEN is partner), but also their use in a more general context.

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Lawaree, E., Gillet, S., Louis, G., Tilquin, F., Le Blastier, S., Cambier, P., and Matroule, J.Y. (2016). Caulobacter crescentus intrinsic dimorphism provides a prompt bimodal response to copper stress. Nat Microbiol 1, 16098.
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