Growth curves comparing the fitness of genetic backgrounds expressing different serotypes.

<p>(A) Effect of capsule switching on the growth of two isolates from SC9. Three replicate experiments (i-iii) are shown in which six mutants were compared. Four were constructed based on isolate R34-3029 (diamond points): one in which the native 23F capsule was restored (orange); a within-serogroup switch to the 23B capsule (red); a between-serogroup switch to the 18C capsule (light blue); and a further between-serogroup switch to the 6B capsule (blue). Two other mutants were constructed based on isolate BR1014 (square points): one in which the native 23B capsule was restored (orange), and a within-serogroup switch to 23F (red). (B) Effect of capsule switching on the growth of two isolates from SC13. Three replicate experiments (i-iii) are shown in which six mutants were compared. Three mutants were based on isolate MD5037 (circular points): a restoration of the native 6B capsule (orange); a within-serogroup switch to the 6C capsule (red); and a between-serogroup switch to the 15F capsule (blue). The other three mutants were based on isolate MD5030 (triangular points): a restoration of the native 6C capsule (orange), a within-serogroup switch to the 6B capsule (red); and a between-serogroup switch to the 15F capsule (blue).