Due to the inappropriate use of florfenicol in agricultural practice, florfenicol resistance has become increasingly serious. In this work, we studied the novel florfenicol resistance mechanism of an animal-derived Leclercia adecarboxylata strain R25 with high-level florfenicol resistance. A random genomic DNA library was constructed to screen the novel florfenicol resistance gene. Gene cloning, gene knockout, and complementation combined with the minimum inhibitory concentration (MIC) detection were conducted to determine the function of the resistance-related gene. Sequencing and bioinformatics methods were applied to analyze the structure of the resistance gene-related sequences. Finally, we obtained a regulatory gene of an RND (resistance-nodulation-cell division) system, ramA, that confers resistance to florfenicol and other antibiotics. The ramA-deleted variant (LA-R25ΔramA) decreased the level of resistance against florfenicol and several other antibiotics, while a ramA-complemented strain (pUCP24-prom-ramA/LA-R25ΔramA) restored the drug resistance. The whole-genome sequencing revealed that there were five RND efflux pump genes (mdtABC, acrAB, acrD, acrEF, and acrAB-like) encoded over the chromosome, and ramA located upstream of the acrAB-like genes. The results of this work suggest that ramA confers resistance to florfenicol and other structurally unrelated antibiotics, presumably by regulating the RND efflux pump genes in L. adecarboxylata R25.
- MeSH
- antibakteriální látky farmakologie MeSH
- bakteriální proteiny genetika metabolismus MeSH
- Enterobacteriaceae účinky léků genetika metabolismus MeSH
- Escherichia coli genetika MeSH
- genový knockout MeSH
- klonování DNA MeSH
- mikrobiální testy citlivosti MeSH
- mnohočetná bakteriální léková rezistence účinky léků genetika MeSH
- RNA ribozomální 16S MeSH
- sekvenování celého genomu MeSH
- thiamfenikol analogy a deriváty MeSH
- trans-aktivátory genetika MeSH
- výpočetní biologie MeSH
- Publikační typ
- časopisecké články MeSH
