Fig. 1.

Mutation of ax21, raxH, or raxR has pleiotropic effects in S. maltophilia K279a. The ax21, raxH, and the raxR mutants show reduced motility in 0.6% Eiken agar (A), reduced tolerance to the aminoglycoside tobramycin at 100 μg/ml as revealed by a killing curve (B), reduced biofilm formation on glass as quantified by crystal violet staining (C), and reduced virulence in the Galleria mellonella larva infection model (D). These mutant phenotypes could be restored to wild-type levels in all cases through complementation by in trans expression of a wild-type copy of their respective gene. All methods have been described previously (3).