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Research article2023Peer reviewedOpen access

Characterisation of meropenem-resistant Bacillus sp. FW 1 isolated from biogas digestate

Sun, He; Levenfors, Jolanta J.; Brandt, Christian; Schnurer, Anna


Recently a Bacillus sp. strain FW 1 was isolated from biogas digestate and shown to have novel resistance to meropenem (MEM), of critical importance in human medicine. MEM-resistance has so far only been described for one species within the genus Bacillus, that is, Bacillus cereus. Bacillus is an abundant representative of the microbial community in biogas digesters and consequently, the finding indicates a risk of spreading such resistance when using the digestate as fertiliser. In this study, the Bacillus strain was characterised and classified as Heyndrickxia oleronia (previous Bacillus oleronius), previously not described to harbour MEM-resistance. The mechanism of resistance was explored by metallo-beta-lactamase (MBL) production, mapping of carbapenemase genes and genome analysis. The transferability of MEM-resistance in strain FW 1 was investigated by plasmid transformation/conjugation, combined with genome analysis. The results confirmed MBL production for both strain FW 1 and the type strain H. oleronia DSM 9356(T). However, elevated MEM resistance was found for strain FW 1, which was suggested to be caused by the production of unclassified carbapenemase, or overexpression of MBL. Moreover, the results suggest that the MEM-resistance of strain FW 1 is not transferable, thus representing a limited risk of MEM-resistance spread to the environment when using digestate on arable land.

Published in

Environmental Microbiology Reports
2023, Volume: 16, number: 1
Publisher: WILEY

      SLU Authors

    • Associated SLU-program

      AMR: Bacteria

      Sustainable Development Goals

      Ensure healthy lives and promote well-being for all at all ages

      UKÄ Subject classification

      Environmental Sciences

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