A Single Residue within the MCR-1 Protein Confers Anticipatory Resilience.

Autor:	Frantz R; Institute of Medical Microbiology, Justus Liebig University Giessen, Giessen, Germany.; German Center for Infection Research, Partner Site: Giessen-Marburg-Langen, Giessen, Germany., Gwozdzinski K; Institute of Medical Microbiology, Justus Liebig University Giessen, Giessen, Germany.; German Center for Infection Research, Partner Site: Giessen-Marburg-Langen, Giessen, Germany., Gisch N; Division of Bioanalytical Chemistry, Priority Area Infections, Research Center Borstel, Leibniz Lung Center, Borstel, Germany., Doijad SP; Institute of Medical Microbiology, Justus Liebig University Giessen, Giessen, Germany.; German Center for Infection Research, Partner Site: Giessen-Marburg-Langen, Giessen, Germany., Hudel M; Institute of Medical Microbiology, Justus Liebig University Giessen, Giessen, Germany., Wille M; Institute of Hygiene and Environmental Medicine, Justus Liebig University Giessen, Giessen, Germany., Abu Mraheil M; Institute of Medical Microbiology, Justus Liebig University Giessen, Giessen, Germany., Schwudke D; Division of Bioanalytical Chemistry, Priority Area Infections, Research Center Borstel, Leibniz Lung Center, Borstel, Germany.; German Center for Infection Research, Partner Site: Hamburg-Lübeck-Borstel-Riems, Borstel, Germany.; Airway Research Center North, Partner Site: Research Center Borstel, Borstel, Germany., Imirzalioglu C; Institute of Medical Microbiology, Justus Liebig University Giessen, Giessen, Germany.; Hessian University Competence Center for Hospital Hygiene, Justus Liebig University Giessen, Giessen, Germany.; German Center for Infection Research, Partner Site: Giessen-Marburg-Langen, Giessen, Germany., Falgenhauer L; Institute of Hygiene and Environmental Medicine, Justus Liebig University Giessen, Giessen, Germany.; Hessian University Competence Center for Hospital Hygiene, Justus Liebig University Giessen, Giessen, Germany.; German Center for Infection Research, Partner Site: Giessen-Marburg-Langen, Giessen, Germany., Ehrmann M; Center of Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, Essen, Germany.; School of Biosciences, Cardiff University, Cardiff, United Kingdom., Chakraborty T; Institute of Medical Microbiology, Justus Liebig University Giessen, Giessen, Germany.; Hessian University Competence Center for Hospital Hygiene, Justus Liebig University Giessen, Giessen, Germany.; German Center for Infection Research, Partner Site: Giessen-Marburg-Langen, Giessen, Germany.
Jazyk:	angličtina
Zdroj:	Microbiology spectrum [Microbiol Spectr] 2023 Jun 15; Vol. 11 (3), pp. e0359222. Date of Electronic Publication: 2023 Apr 18.
DOI:	10.1128/spectrum.03592-22
Abstrakt:	The envelope stress response (ESR) of Gram-negative enteric bacteria senses fluctuations in nutrient availability and environmental changes to avert damage and promote survival. It has a protective role toward antimicrobials, but direct interactions between ESR components and antibiotic resistance genes have not been demonstrated. Here, we report interactions between a central regulator of ESR viz. , the two-component signal transduction system CpxRA ( c onjugative p ilus e x pression), and the recently described mobile colistin resistance protein (MCR-1). Purified MCR-1 is specifically cleaved within its highly conserved periplasmic bridge element, which links its N-terminal transmembrane domain with the C-terminal active-site periplasmic domain, by the CpxRA-regulated serine endoprotease DegP. Recombinant strains harboring cleavage site mutations in MCR-1 are either protease resistant or degradation susceptible, with widely differing consequences for colistin resistance. Transfer of the gene encoding a degradation-susceptible mutant to strains that lack either DegP or its regulator CpxRA restores expression and colistin resistance. MCR-1 production in Escherichia coli imposes growth restriction in strains lacking either DegP or CpxRA, effects that are reversed by transactive expression of DegP. Excipient allosteric activation of the DegP protease specifically inhibits growth of isolates carrying mcr-1 plasmids. As CpxRA directly senses acidification, growth of strains at moderately low pH dramatically increases both MCR-1-dependent phosphoethanolamine (PEA) modification of lipid A and colistin resistance levels. Strains expressing MCR-1 are also more resistant to antimicrobial peptides and bile acids. Thus, a single residue external to its active site induces ESR activity to confer resilience in MCR-1-expressing strains to commonly encountered environmental stimuli, such as changes in acidity and antimicrobial peptides. Targeted activation of the nonessential protease DegP can lead to the elimination of transferable colistin resistance in Gram-negative bacteria. IMPORTANCE The global presence of transferable mcr genes in a wide range of Gram-negative bacteria from clinical, veterinary, food, and aquaculture environments is disconcerting. Its success as a transmissible resistance factor remains enigmatic, because its expression imposes fitness costs and imparts only moderate levels of colistin resistance. Here, we show that MCR-1 triggers regulatory components of the envelope stress response, a system that senses fluctuations in nutrient availability and environmental changes, to promote bacterial survival in low pH environments. We identify a single residue within a highly conserved structural element of mcr-1 distal to its catalytic site that modulates resistance activity and triggers the ESR. Using mutational analysis, quantitative lipid A profiling and biochemical assays, we determined that growth in low pH environments dramatically increases colistin resistance levels and promotes resistance to bile acids and antimicrobial peptides. We exploited these findings to develop a targeted approach that eliminates mcr-1 and its plasmid carriers. Competing Interests: The authors declare no conflict of interest.
Databáze:	MEDLINE
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