Marine-derived quorum-sensing inhibitory activities enhance the antibacterial efficacy of tobramycin against Pseudomonas aeruginosa.

Busetti, A., Shaw, G., Megaw, J., Gorman, S.P., Maggs, C. and Gilmore, B.F., 2015. Marine-derived quorum-sensing inhibitory activities enhance the antibacterial efficacy of tobramycin against Pseudomonas aeruginosa. Marine Drugs, 13 (1), 1 - 28.

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DOI: 10.3390/md13010001

Abstract

Bacterial epiphytes isolated from marine eukaryotes were screened for the production of quorum sensing inhibitory compounds (QSIs). Marine isolate KS8, identified as a Pseudoalteromonas sp., was found to display strong quorum sensing inhibitory (QSI) activity against acyl homoserine lactone (AHL)-based reporter strains Chromobacterium violaceum ATCC 12472 and CV026. KS8 supernatant significantly reduced biofilm biomass during biofilm formation (-63%) and in pre-established, mature P. aeruginosa PAO1 biofilms (-33%). KS8 supernatant also caused a 0.97-log reduction (-89%) and a 2-log reduction (-99%) in PAO1 biofilm viable counts in the biofilm formation assay and the biofilm eradication assay respectively. The crude organic extract of KS8 had a minimum inhibitory concentration (MIC) of 2 mg/mL against PAO1 but no minimum bactericidal concentration (MBC) was observed over the concentration range tested (MBC > 16 mg/mL). Sub-MIC concentrations (1 mg/mL) of KS8 crude organic extract significantly reduced the quorum sensing (QS)-dependent production of both pyoverdin and pyocyanin in P. aeruginosa PAO1 without affecting growth. A combinatorial approach using tobramycin and the crude organic extract at 1 mg/mL against planktonic P. aeruginosa PAO1 was found to increase the efficacy of tobramycin ten-fold, decreasing the MIC from 0.75 to 0.075 µg/mL. These data support the validity of approaches combining conventional antibiotic therapy with non-antibiotic compounds to improve the efficacy of current treatments.

Item Type:Article
ISSN:1660-3397
Uncontrolled Keywords:Anti-Bacterial Agents ; Biofilms ; Chromobacterium ; Microbial Sensitivity Tests ; Pseudoalteromonas ; Pseudomonas aeruginosa ; Quorum Sensing ; Seawater ; Tobramycin
Subjects:UNSPECIFIED
Group:Faculty of Science & Technology
ID Code:24479
Deposited By: Unnamed user with email symplectic@symplectic
Deposited On:08 Aug 2016 15:03
Last Modified:08 Aug 2016 15:03

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