Association between gut microbiome and metabolome in mice suffering from acute carbapenem-resistant Escherichia coli infection.

Increasing evidence highlighted the metabolic associations between host and gut microbiota during infection. However, how host-gut microbiota metabolic partnership response to carbapenem-resistant Escherichia coli (CRE) infection has yet to be elucidated. In this study, we subjected the mice to a single intraperitoneal injection of CRE and studied the alterations of the small molecule metabolites derived from host-microbial co-metabolism, as well as the gut microbiome in mice, at 24 h after infection by a two-level strategy. A panel of metabolites in feces and serum, were found to alter significantly in the CRE group, including 26 joint metabolites between them. Meanwhile, the relative abundance of 14 OTUs in Firmicutes (10 OTU), Bacteroidetes (2 OTU), Actinomycetes (1 OTU), and Proteobacteria (1 OTU) were observed to change after infection. Association analyses demonstrated that 9 OTUs including six in the Firmicutes phylum, two in the Bacteroidetes phylum, and one in the Actinomycetes phylum, were associated with the changes of 49 fecal metabolites and 42 serum metabolites. The study of gut microbiota-host metabolic interactions in the early stage of the infection is expected to provide novel diagnostic methods and therapeutic strategies for CRE infection, bring innovative solutions to resolve the current challenge.

Microbial metabolomics and network analysis reveal fungistatic effect of basil (Ocimum basilicum) oil on Candida albicans.

ETHNOPHARMACOLOGICAL RELEVANCE: Fungal infections remain a serious problem worldwide that require effective therapeutic strategies. Essential oil of basil (Ocimum basilicum L., BEO) being traditionally used extensively for the treatment of bacterial and fungal infection has a long history. However, the potential mechanism of action was still obscure, especially from the metabolic perspective. MATERIALS AND METHODS: The fungistatic effect of BEO on Candida albicans (C. albicans) was evaluated by measurement of minimum inhibitory concentration (MIC) and morphological analysis. A high-coverage microbial metabolomics approach was utilized to identify the alterations of intracellular metabolites of C. albicans at mid-logarithmic growth phase in response to the subinhibitory concentration of BEO, by using gas chromatography coupled to time-of-fight mass spectrometry (GC-TOFMS). Following the metabolic fingerprinting, systematic network analysis was performed to illustrate the potential mechanism of BEO involved in the suppression of C. albicans. RESULTS: The damage in cellular membranes of C. albicans treated by BEO above MIC was observed on the scanning electron microscope (SEM) micrographs. Metabolomics results showed that, among 140 intracellular metabolites identified by comparison with reference standards, thirty-four had significantly changed abundances under 0.2 MIC of BEO treatment, mainly involving in central carbon metabolism (glycolysis/gluconeogenesis, pentose phosphate pathway and TCA cycle), amino acids, polyamines and lipids metabolism. Pathway and network analyses further found that fifteen ingredients of BEO mainly terpenoids and phenyl-propanoids, potentially participated in the metabolic regulation and may be responsible for the suppression of C. albicans. CONCLUSIONS: The findings highlighted that integrated microbial metabolomics and network analyses could provide a methodological support in understanding the functional mechanisms of natural antimicrobial agents and contribute to drug discovery.