Study on the resistance of Erysipelothrix rhusiopathiae based on transcriptomics and proteomics

Abstract:

[Background] β-lactam antibiotics are commonly used drugs for the prevention and treatment of swine erysipelas, and penicillin (PG) is the preferred drug. [Objective] The use of transcriptomics and proteomics methods to preliminarily explore the mechanism of Erysipelothrix rhusiopathiae (E. rhusiopathiae) producing penicillin resistance, laying a foundation for further research on the resistance mechanism of E. rhusiopathiae. [Methods] The susceptibility to 26 antibiotics and the minimum inhibitory concentration (MIC) to PG, amoxicillin (AMX) and ampicillin (AMP) of the tested strains AErS, AEr51 and AEr31 were determined by the Kirby-Bauer disk diffusion method and the microdilution method; Then through transcriptomics sequencing (RNA-Seq) technology and tandem mass tag (TMT) quantitative proteomics technology to further explore the molecular mechanism of E. rhusiopathiae producing penicillin resistance. [Results] The resistance rates of AErS, AEr51 and AEr31 to 26 antibiotics were 34.62%, 34.62%, and 26.92%, respectively. AErS and AEr31 were sensitive to all β-lactams antibiotics, while AEr51 was sensitive to other β-lactams antibiotics except PG; the MICs of AErS, AEr51 and AEr31 to PG, AMX and AMP were 0.125, 0.500, 0.250 μg/mL, 32, 4, 2 μg/mL and 0.25, 0.50, 0.50 μg/mL, respectively; RNA-Seq analysis showed a total of 668 differential genes were screened in the AEr51/AErS comparison group, of which 434 were up-regulated and 234 were down-regulated. In the AEr51/AEr31 comparison group, a total of 403 differential genes were screened, of which 275 were up-regulated and 128 were down-regulated. The differentially expressed genes were mainly enriched in the metabolic pathway, ABC transport system, two-component signal transduction system, β-lactam resistance and other pathways, and the results of RT-qPCR verification were basically the same; TMT analysis showed that a total of 167 differential proteins were screened in the AEr51/AErS comparison group, among which 86 were up-regulated and 81 were down-regulated. A total of 159 differential proteins were screened in the AEr51/AEr31 comparison group, of which 80 were up-regulated and 79 were down-regulated. Differentially expressed proteins were significantly enriched in metabolic pathways related to microorganisms, amino acids, carbon, sulfur, and pyrimidine metabolism, and the results of PRM targeting verification were basically the same [Conclusion] ABC transport system, two-component signal transduction system, β-lactam resistance and other pathways played an important role in the development of E. rhusiopathiae resistance to PG, and were accompanied by life processes, such as microorganisms, amino acid, carbon, sulfur, and pyrimidine metabolism, etc.