Temocillin Resistance in the Enterobacter cloacae Complex Is Conferred by a Single Point Mutation in BaeS, Leading to Overexpression of the AcrD Efflux Pump - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Antimicrobial Agents and Chemotherapy Année : 2023

Temocillin Resistance in the Enterobacter cloacae Complex Is Conferred by a Single Point Mutation in BaeS, Leading to Overexpression of the AcrD Efflux Pump

Résumé

The Enterobacter cloacae complex (ECC) has become a major opportunistic pathogen with antimicrobial resistance issues. Temocillin, an "old" carboxypenicillin that is remarkably stable toward β-lactamases, has been used as an alternative for the treatment of multidrug-resistant ECC infections. Here, we aimed at deciphering the never-investigated mechanisms of temocillin resistance acquisition in . By comparative genomic analysis of two clonally related ECC clinical isolates, one susceptible (Temo_S [MIC of 4 mg/L]) and the other resistant (Temo_R [MIC of 32 mg/L]), we found that they differed by only 14 single-nucleotide polymorphisms, including one nonsynonymous mutation (Thr175Pro) in the two-component system (TCS) sensor histidine kinase BaeS. By site-directed mutagenesis in Escherichia coli CFT073, we demonstrated that this unique change in BaeS was responsible for a significant (16-fold) increase in temocillin MIC. Since the BaeSR TCS regulates the expression of two resistance-nodulation-cell division (RND)-type efflux pumps (namely, AcrD and MdtABCD) in E. coli and Salmonella, we demonstrated by quantitative reverse transcription-PCR that , , and genes were significantly overexpressed (15-, 11-, and 3-fold, respectively) in Temo_R. To confirm the role of each efflux pump in this mechanism, multicopy plasmids harboring or were introduced into either Temo_S or the reference strain E. cloacae subsp. ATCC 13047. Interestingly, only the overexpression of conferred a significant increase (from 8- to 16-fold) of the temocillin MIC. Altogether, we have shown that temocillin resistance in the ECC can result from a single BaeS alteration, likely resulting in the permanent phosphorylation of BaeR and leading to AcrD overexpression and temocillin resistance through enhanced active efflux.

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Guérin et al - 2023 - Temocillin Resistance in the Enterobacter cloacae _Manuscript ENCC Temo-R AAC Final ref R1.pdf (1.75 Mo) Télécharger le fichier
Figure S1 - Alignement BaeS Final R1.pdf (87.92 Ko) Télécharger le fichier
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hal-04117033 , version 1 (29-06-2023)

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François Guérin, François Gravey, Sophie Reissier, Malo Penven, Charlotte Michaux, et al.. Temocillin Resistance in the Enterobacter cloacae Complex Is Conferred by a Single Point Mutation in BaeS, Leading to Overexpression of the AcrD Efflux Pump. Antimicrobial Agents and Chemotherapy, 2023, 67 (6), pp.e00358-23. ⟨10.1128/aac.00358-23⟩. ⟨hal-04117033⟩
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