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: As 7HI diminished virulence factors in P. aeruginosa more than indole (Table 1 and Fig. 1) and as 7HI abolished swarming motility (Fig. 2), we evaluated the ability of P. aeruginosa pre‐treated with 7HI or diluent dimethylformamide (DMF) as a control to colonize guinea pig lungs after infection. Pulmonary colonization was examined immediately after infection until 48 h post infection (Fig. 4A). Colonization of the lung by P. aeruginosa treated with 7HI was reduced by 25%, and 7HI‐treated bacteria are cleared more easily from the lungs for the first 4 h post infection, leading to a greater than 50% reduction in pulmonary bacteria by this time point. In the acute model, both the 7HI‐ and DMF‐treated P. aeruginosa continue to be expelled from the lungs, resulting in nearly complete clearance of the bacterial pneumonia by 48 h. As it was not possible to maintain 7HI levels with the bacteria in vivo, the differences between DMF‐ and 7HI‐treated bacteria decrease over the course of this experiment, as expected.
Affiliation: Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843-3122, USA.