Indole and 7-hydroxyindole diminish Pseudomonas aeruginosa virulence.
Bottom Line: Corroborating these microarray results, indole and 7HI decreased production of pyocyanin, rhamnolipid, PQS and pyoverdine and enhanced antibiotic resistance.In addition, indole affected the utilization of carbon, nitrogen and phosphorus, and 7HI abolished swarming motility.Hence, indole-related compounds have potential as a novel antivirulence approach for the recalcitrant pathogen P. aeruginosa.
Affiliation: Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843-3122, USA.Show MeSH
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Mentions: In the microarray samples of P. aeruginosa, the concentration of indole and 7HI decreased significantly after 7 h (1.0 mM indole decreased to 0.68 mM and 0.5 mM 7HI decreased to 0.154 mM); hence, the degradation of indole and 7HI was quantified by measuring the concentration of extracellular indole and 7HI using HPLC. It was found that P. aeruginosa degrades indole in LB medium at 1.04 ± 0.04 nmol min−1 (mg protein)−1 and degrades 7HI in LB medium at 2.6 ± 0.1 nmol min−1 (mg protein)−1 while there was no significant change of indole and 7HI concentrations with the negative control (dead cells) (Fig. 3A and B). Furthermore, P. aeruginosa PAO1 does not utilize either indole (1 or 2 mM) or 7HI (0.5 or 2 mM) as a sole source of carbon and energy (data not shown) although P. aeruginosa Gs isolated from mangrove sediments (Yin et al., 2005) and Pseudomonas sp. ST‐200 from soil (Doukyu and Aono, 1997) grow on indole.
Affiliation: Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843-3122, USA.