Fig 6. Effect of neuraminidases on colonization in vivo.

(A) Adult mice were intranasally infected with a suspension containing equal amounts of Type 23F::pilus-1 and isogenic double neuraminidase mutant. Colonization density was assessed 4h, 24h and 5 days p.i. in the URT lavages to calculate the competitive index (CI). Dotted line represents CI = 1. Group medians were compared to a CI = 1 by one sample T and Wilcoxon signed rank test and resulting p-values are indicated ****, p<0.0001. (B) Adult (left panel) and infant (right panel) mice were intranasally infected with Type 23F::pilus-1 or ΔnanA,nanB::janus. Colonization density was assessed at 4h, 24h and 5 days p.i. in adult mice and 24h and 5 days p.i. in infant mice. Experiments were repeated twice and groups represent n = 5–15 animals. Error bars correspond to S.D. by Mann-Whitney test.