FIG. 5.

Assays of the viability of wild-type strain MC58, the Δhfq mutant, and the Δhfq_C complemented mutant. Cells were grown to an OD₆₀₀ of 0.5 in GC broth (1 mM IPTG was added for expression of Hfq in the complemented mutant), diluted, and incubated with the antimicrobial compounds indicated. Samples were taken at 15, 30, and/or 60 min, and viable cell counts were determined by plating. The final concentrations of compounds used were as follows: Tween, 0.05%; SDS, 0.01%; Triton X-100, 0.1%; hydrogen peroxide, 5 mM; xanthine oxidase, 4.3 mM xanthine and 300 mU xanthine oxidase; paraquat, 5 mM; NaCl, 4.5 M; LL-37, 2 μM; and polymyxin B, 10 μg/ml.