Extended Data Fig. 4: Biofilm formation of probiotic and blood L. rhamnosus isolates.

Blood isolates from patients receiving (R1-R6) and those not receiving probiotics (N5, N9, N10, N11), as well as selected probiotic isolates, were tested for biofilm formation. Isolates are grouped by similar mutations, as depicted in the grid below the isolate labels. Isogenic probiotic isolates from different probiotic capsules were used as controls, if available, as were controls for mutations found in blood isolates, when available. In Px-y, x is probiotic batch number, y is probiotic isolate number. Bars represent means of three independent experiments performed on different days, with three technical replicates per isolate in each experiment. Error bars depict the s.e.m. ****P < 0.0001 by ANOVA followed by Tukey’s multiple comparisons test for the pairwise comparison of any of the isolates making biofilm (defined as OD₅₇₀ > 1) compared to either P2-1, N5, N9, N10, N11, or medium control. There were no statistically significant differences among the isolates making biofilm or among the isolates not making biofilm.