We screened a collection of 61 S. aureus clinical isolates, from CF lung and bloodstream infections (SI Appendix, Table S1), and found that the majority of them (78.7%) had increased yellow pigmentation when grown in proximity to PAO1, suggesting STX induction (SI Appendix, Fig. S4A and Table S2). The gene discussed is SMOX; the disease is cystic fibrosis.