Fig. 5.

RrgA is involved in pilus-mediated colonization of the upper respiratory tract in mice. Mice were challenged intranasally with a low dose of T4, T4ΔrrgA or T4ΔrrgBC (c. 7 × 10⁴ cfu per mouse). Bacterial density in the nasopharynx was determined 7 days post infection. Mice infected with T4ΔrrgA had significantly fewer bacteria in the nasopharynx than mice infected with T4 or T4ΔrrgBC (*P< 0.01, n = 3 independent replicates of 10 mice per group per replicate, using the Kruskal–Wallis test with Dunn's post testing).