Transcriptomic and proteomic responses of Microbacterium sp. C448 exposed to sulfamethazine antibiotic
Résumé
The Microbacterium sp. C448 was isolated from a soil regularly exposed to sulfamethazine(SMZ), for its ability to partly mineralise this antibiotic and other related sulfonamides.The aim of our study was to explore its metabolic adaptation towards exposure to SMZenvironmental (10 mg/L) and medicinal (250 mg/L) concentrations. Its transcriptomic andproteomic responses were analysed by focusing on the degradation regulon (sad genes) andresistance genes (folP and sul1).The transcriptomic and proteomic results were essentially congruent whatever theconcentrations tested. In culture conditions, exposure to the highest concentration of SMZ led tothe highest sad expression and Sad production, confirming these proteins’ role insulfamethazine degradation in cellulo. Moreover, when sulfamethazine was completelydegraded, Sad production tends to return to the basal level observed under control conditions.Congruence of transcriptomic and proteomic results was also observed for resistance genes.Although Dihydropteroate synthase (DHPS)-Sul1 protein was 100-fold more produced than thatof DHPS-FolP, both were expressed at a basal level and were not affected by SMZ exposure.Moreover, non-targeted analyses showed overexpression and overproduction of a putativesulphate exporter W0Z8D9 in Microbacterium sp. C448 exposed to the highest SMZconcentration. In addition to sul1 resistance genes, this efflux pump could be involved in thesulfamethazine detoxification process by exporting the SO2 formed during its degradation.Acknowledgements : The authors thank the National Research Agency for its financial support(ANTIBIOTOX project ; Grant ANR-17-CE34-0003).