Clearing the FoG: Antifungal tolerance is a subpopulation effect that is distinct from resistance and is associated with persistent candidemia

Alexander Rosenberg; Iuliana V. Ene; Maayan Bibi; Shiri Zakin; Ella Shtifman Segal; Naomi Ziv; Alon M. Dahan; Arnaldo L. Colombo; Richard J. Bennett; Judith Berman

( Supplementary Fig. 3e) . A series of strains derived from SC5314 by passaging were 154 particularly sensitive to media differences, with lower RAD and higher FoG levels on rich 155 medium (YPD) than on casitone medium ( Supplementary Fig. 3f ), emphasizing that assays 156 must be performed under consistent conditions to ensure reproducible results. Importantly, FoG/SMG is independent of cell density. Importantly, these results establish that FoG levels 167 represent the proportion of the population that can form colonies or grow above the MIC. area occupied by light pixels and the change in this area over time are proxies for colony size and growth rate, respectively 74 . Different C. albicans isolates exhibited different initial time of Fig. 2e,f) . Notably, the ∆ToA (ToA on FLC -ToA without FLC) of high FoG isolates was shorter 184 than that of low FoG isolates (Fig. 2f) , and correlated with overall FoG levels (Fig. 2g) . This 185 suggests that high FoG strains overcome the inhibitory pressures of the antifungal more 186 efficiently than low FoG strains. Consistent with this, in liquid assays with drug, highly tolerant 187 isolates also displayed shorter lag times than related isolates with low tolerance levels 188 ( Supplementary Fig. 5a ).