Identifying Fecal Microbiome Composition

The feces of both OVA/alum mice and PBS/alum mice were suspended in 20 volumes of PBS, inoculated onto plates containing Columbia agar with 5% sheep blood, and cultured anaerobically for 2 days at 37°C. To identify viable bacteria in the feces of the mice, a portion of each fresh colony that developed on each plate was smeared onto a target slide as a sample. These samples were covered with α-cyano-4-hydroxycinnamic acid matrix solution and loaded into a Vitek MALDI-TOF MS system (bioMérieux, Lyon, France). The spectra of the samples were analyzed using the Myla database to identify the species of origin (42 (link)). A total of 48 fresh colonies from each group of mice were analyzed.