1. Peptide nucleic acid restores colistin susceptibility through modulation of MCR-1 expression in Escherichia coli.
- Author
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Wang, Xiaoming, Wang, Yao, Ling, Zhuoren, Zhang, Chaoyang, Fu, Mingming, Wang, Yang, Wang, Shaolin, Zhang, Suxia, and Shen, Zhangqi
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COLISTIN ,PEPTIDE nucleic acids ,ESCHERICHIA coli ,PROTEINS ,RESEARCH ,RESEARCH methodology ,MEDICAL cooperation ,EVALUATION research ,COMPARATIVE studies ,ESCHERICHIA coli diseases ,GENES ,DRUG resistance in microorganisms ,NUCLEIC acids ,ANTIBIOTICS ,MICROBIAL sensitivity tests ,PHARMACODYNAMICS - Abstract
Background: Plasmid-mediated mechanisms of drug resistance accelerate the spread of polymyxin resistance, leaving clinicians with few or no antibacterial options for the treatment of infections caused by MDR bacteria, especially carbapenemase-producing strains.Objectives: To evaluate the associations among promoter sequence variation, mcr-1 expression, host factors and levels of colistin resistance and to propose antisense agents such as peptide nucleic acids (PNAs) targeting mcr-1 as a tool to restore colistin susceptibility through modulation of MCR-1 expression in Escherichia coli.Methods: A β-galactosidase assay was performed to study mcr-1 promoter activity. Quantitative real-time PCR and western blot assays were used to identify the expression level of MCR-1 in WT strains and transformants. Three PNAs targeting different regions of mcr-1 were designed and synthesized to determine whether they can effectively inhibit MCR-1 expression. MIC was measured to test colistin susceptibility in the presence or absence of PNA-1 in mcr-1-carrying E. coli.Results: Variation in the mcr-1 promoter sequence and host species affect promoter activity, MCR-1 expression levels and colistin MICs. One PNA targeting the ribosome-binding site fully inhibited the expression of mcr-1 at a concentration of 4 μM, resulting in significantly increased susceptibility to colistin. The MIC90 of colistin decreased from 8 to 2 mg/L (P < 0.05) in the presence of 4 μM PNA.Conclusions: These findings suggest that the antisense approach is a possible strategy to combat mcr-1-mediated resistance as well as other causes of emerging global resistance. [ABSTRACT FROM AUTHOR]- Published
- 2020
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