As shown in Fig. S2, both PAO1 and PA14 reached biofilm loads comparable with those reported for CF (sputum microbiology studies routinely give upper limits on the detected P. aeruginosa load of 107–1010 c.f.u. ml−1 [28–30] and P. aeruginosa aggregates, suggestive of detached biofilm fragments, are observable in CF sputum [2, 31, 32]). Here, SMOX is linked to cystic fibrosis.