Figure 4.

Lung function and sputum biomass in patients born after January 1, 1997 and infected by different MRSA clusters. A. Lung function in 2017 (annual best FEV₁ % predicted) is shown as a function of age. Patients with Cluster A MRSA are depicted by circles, Cluster B by diamonds. Two subjects with Cluster C MRSA are omitted. Generalized linear regression results are at bottom; advancing age and Cluster A MRSA were associated with lower lung function. B. Trends in FEV₁ % predicted by MRSA cluster between 2011 and 2017. Symbols indicate mean FEV₁ % predicted by MRSA types, Cluster A (circles), Cluster B (diamonds). Bars indicate standard deviation. The number of patients examined per year is given at bottom. The average FEV₁ % predicted for patients with Cluster A MRSA decreased with time (slope −3.7% yr −1, P < 0.001). The average FEV₁ % predicted for patients infected with Cluster B MRSA was stable (slope −0.5 % yr −1, P = 0.72). C-D. Quantitation of CF microorganisms in sputum from young patients infected by MRSA belonging to cluster A or cluster B. Each dot represents a different sputum culture. C. MRSA, D. P. aeruginosa. * P < 0.01 by Wilcoxon rank sum test