FIG 4.

NTHi colonization rate as a percentage of culture-positive ME samples of ccl3^−/− and WT mice. We found no significant differences in colonization rates of NTHi in the first 5 days post-NTHi inoculation. After day 5, colonization rates of NTHi diverged. ccl3^−/− MEs were colonized by NTHi to a significantly higher degree on day 10 and 14 after NTHi inoculation (*, P < 0.05; **, P < 0.01 by a Fisher-Irwin t test for proportions). By day 21, no NTHi were cultured from WT mice. In contrast, NTHi remained present in the MEs of ccl3^−/− animals throughout the observation period (n ≥ 6 MEs per time point and strain).