Fig. 3: Bacteroides serine palmitoyltransferase gene (spt) presence in stool is associated with a protective memory B cell response to OCV.

(a) Relative abundance of Bacteroides spt among vaccine responders (R) who had both an IgA- and IgG-specific OSP response to OCV and nonresponders (NR) who lacked both of these OSP responses. Each dot represents one participant. N = 10 nonresponders and n = 9 responders were included in our analysis of spt. Bars represent the mean with SEM. A two-sided Mann–Whitney test was performed. *, P = 0.0279. (b) Targeted quantitative mass spectrometry-based lipidomics of fecal samples from vaccine responders and nonresponders at the time OCV was administered. The quantities of the most abundant lipid species detected in study participant stool are listed in Supplementary Table 3. N = 7 nonresponders and n = 9 responders fecal samples were used for lipidomics. P-values from two-sided multiple Mann–Whitney tests are displayed on the y-axis with -log10 transformation, and the x-axis is fold change with log2 transformation. Dotted lines represent fold change of 1 or −1, and P-value of 0.05 along the x- and y-axis, respectively. CER: ceramides, DCER: dihydroceramides, HCER: hexosylceramides. Other lipids include sphingomyelin, cholesterol esters, diacylglycerols, free fatty acids, and triacylglycerols. Source data are provided as a Source Data file.