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. Author manuscript; available in PMC: 2018 Jan 11.
Published in final edited form as: Cell Host Microbe. 2017 Jan 11;21(1):73–83. doi: 10.1016/j.chom.2016.12.005

Figure 7. Pneumolysin Expression Promotes Bacterial Survival and Infectivity outside of the Host.

Figure 7

(A–C) To compare ex vivo survival, we incubated pneumococci in PBS and viable counts determined at the times indicated. Prior to incubation in PBS, bacteria were obtained from nasal lavages obtained at age 9 days from mice colonized at age 4 days with the strain indicated (A), broth culture in nutrient medium (B), or nasal lavages at age 9 days from mice colonized at age 4 days with ply− and then treated daily with an IN dose of Ply or PdB (100 ng/day) or PBS control (C). Statistical comparisons are to the group(s) without pneumolysin. *p < 0.05, **p < 0.01.

(D) Nasal lavages obtained from T4S or ply− colonized mice were diluted to the desired density in PBS and incubated for 4 hr at 30° C. Aliquots then used to compare the infectious dose by IN inoculation of 4-day-old pups. Colonization density at age 6 days is shown relative to the inoculum size.