Fig. 4. Production and catabolism of acetoin by competitive and coexisting strains of S. aureus and P. aeruginosa.

a Acetoin concentration in P. aeruginosa supernatant inoculated with S. aureus strains from competition and coexistence couples. Each S. aureus strain from competition (n = 12, grey bar) and coexistence (n = 12, black bar) couples was cultivated in P. aeruginosa PA2600 filtered supernatant and acetoin was quantified from the supernatant after 6 h of culture. Bars represent the median acetoin concentration ± 95% CI. ****P < 0.0001 Mann–Whitney test. b Acetoin concentration in S. aureus supernatant inoculated with P. aeruginosa strains from competition and coexistence couples. Each P. aeruginosa strain from competition (n = 12, grey bar) and coexistence (n = 12, black bar) couples was cultivated in S. aureus SA2599 filtered supernatant and acetoin was quantified from the supernatant after 4 h of culture. Sterile supernatant was used as control (white bar) for acetoin degradation. Bars represent the median acetoin concentration ± 95% CI. The dotted line indicates the initial acetoin concentration. *P_adj < 0.05, ***P_adj < 0.001 Kruskall–Wallis test with Dunn’s correction.