Extended Data Figure 7: Effects of airway mucins on infection and growth of S. aureus.

a–e, USA300 infection (10⁷ CFU intranasally) in Muc5b^+/+ and Muc5b^−/− mice. a, Changes in body weights during the first week in Muc5b^+/+ animals (blue circles, n = 7), Muc5b^−/− animals that recovered fully from infection (open red circles, n = 4), and Muc5b^−/− animals that did not survive to 21 days (filled red circles, n = 6). b–e, On day 21 (surviving mice), or on the day in which a >15% loss of body weight was discovered (non-surviving mice), lungs and spleens were cultured. One non-survivor was found to have died in its cage and not cultured. Incidence of positive cultures (b) and numbers of CFUs (c) in infected Muc5b^+/+ and Muc5b^−/− lungs. d, e, Spleen-culture incidences and numbers of CFUs. Error bars, s.e.m. in a, c, e. Data were analysed using Student’s t-test in a (day 7) and c, and Fisher’s exact test in b and d. Because all values for Muc5b^+/+ mice are zeroes in e, Mann–Whitney and Wilcoxon ranked sums tests were used. For all statistical analyses, P < 0.05 was considered significant. f, USA300 growth in medium containing MUC5AC or MUC5B (2–250 µg ml⁻¹). Purified mucin stocks were solubilized in urea. Separate growth curves were thus also measured in serially diluted urea at matched concentrations (1.2–150 mM). Each line represents mean growth at a single concentration of mucin or urea over time. Error bars, s.d. from triplicate experiments.