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. 2022 Mar 30;18(3):e1010423. doi: 10.1371/journal.ppat.1010423

Fig 13. Serum susceptibility and phagocyte internalization of S. marcescens strains.

Fig 13

(A) Bacteria were exposed to 40% pooled human serum for 90 minutes. Viability was calculated relative to the number of bacteria present at the start of the experiment. Differences in serum sensitivity were assessed by one-way ANOVA with Dunnett’s multiple comparisons test relative to strain ATCC 13880. (B) Serum sensitivity of UMH9 capsule mutant strains was determined as described for panel A and an unpaired t test was used to determine statistical significance. (C) Adherent U937 cells were infected with S. marcescens strains at an MOI of 20. The proportion of intracellular bacteria was determined relative to the total bacterial inoculum after a 1 h treatment with gentamicin to kill extracellular bacteria. A one-way ANOVA with Dunnett’s multiple comparisons test relative to ATCC 13880 was used to assess statistical significance. (D) Internalization of the UMH9 capsule mutant strain by U937 cells was tested as described for panel C. A unpaired t-test was used to determine statistical significance. Symbols: **, P<0.01; ***, P<0.001; ****, P<0.0001.