GC-MS-based metabolic profiling of Escherichia coli exposed to subinhibitory concentration of enoxacin

Abstract

Objective: The rapid development of bacterial resistance to antibiotics is one of the most recent threats to human health. Understanding the metabolism of pathogens is essential to gain insights into the adaptation strategies that are required to deal with the host environment during infection and to identify new drug targets. In recent years omics technologies have offered new routes to understand adaptation and resistance mechanisms of pathogens against antibiotics at molecular level. In present work, we analyzed the metabolic response of Escherichia coli during treatment with enoxacin to identify metabolic adapdation processes. Methods: Gas chromatography/Mass spectroscopy (GC/MS) based metabolomics approach was used for metabolomics analysis. Metabolites were extracted using methanol: water co-solvent system. After derivatization process, Metabolites separated in GC column and analyzed in MS. MS-DIAL metabolomics and lipidomics platform was performed to analyze raw GC/ MS data. Metabolites were identified with retention index database and quantified relatively between control and enoxacin-treated groups. Statistically significant altered metabolites were investigated via pathway enrichment analysis. Results: Metabolite profile of control and enoxacin-treated groups were compared to observe cellular adaptation against the antibiotic stress. Principal component analysis of GC/MS results showed that there was a dramatic shift at general metabolome structure under antibiotic stress. We identified 92 metabolites and statistical analysis indicated 36 metabolites altered significantly between experimental groups. Pathway enrichment analysis showed that amino acid biosynthesis, glycine, serine, and threonine metabolism, Aminoacyl-tRNA metabolism, purine metabolism, galactose metabolism was induced in E. coli exposed to subinhibitory concentration of enoxacin. Conclusion: In present study, we investigated metabolic adapdation of E. coli against enoxacin-induced stress. Our findings may contribute to current literature to expand the understanding of bacteria-antibiotic interactions at metabolome level.