Skip to main content

Research Repository

Advanced Search

Biotic inactivation of the Pseudomonas aeruginosa quinolone signal molecule


Eliza Ye-Chen Soh

Siri Ram Chhabra

Nigel Halliday


Franziska S. Birmes

Susanne Fetzner


Kok Gan Chan

Professor of Molecular Microbiology


In Pseudomonas aeruginosa, quorum sensing (QS) regulates the production of secondary metabolites, many of which are antimicrobials that impact on polymicrobial community composition. Consequently, quenching QS modulates the environmental impact of P. aeruginosa. To identify bacteria capable of inactivating the QS signal molecule 2-heptyl-3- hydroxy-4(1H)-quinolone (PQS), a minimal medium containing PQS as the sole carbon source was used to enrich a Malaysian rainforest soil sample. This yielded an Achromobacter xylosoxidans strain (Q19) that inactivated PQS, yielding a new fluorescent compound (I-PQS) confirmed as PQS-derived using deuterated PQS. The I-PQS structure was elucidated using mass spectrometry and nuclear magnetic resonance spectroscopy as 2-heptyl-2-hydroxy-1,2-dihydroquinoline- 3,4-dione (HHQD). Achromobacter xylosoxidans Q19 oxidized PQS congeners with alkyl chains ranging from C1 to C5 and also N-methyl PQS, yielding the corresponding 2-hydroxy-1,2-dihydroquinoline-3,4- diones, but was unable to inactivate thePQSprecursor HHQ. This indicates that the hydroxyl group at position 3 in PQS is essential and that A. xylosoxidans inactivates PQS via a pathway involving the incorporation of oxygen at C2 of the heterocyclic ring. The conversion of PQS to HHQD also occurred on incubation with 12/17 A. xylosoxidans strains recovered from cystic fibrosis patients, with P. aeruginosa and with Arthrobacter, suggesting that formation of hydroxylated PQS may be a common mechanism of inactivation.


Soh, E. Y., Chhabra, S. R., Halliday, N., Heeb, S., Müller, C., Birmes, F. S., …Williams, P. (2015). Biotic inactivation of the Pseudomonas aeruginosa quinolone signal molecule. Environmental Microbiology, 17(11),

Journal Article Type Article
Acceptance Date Mar 6, 2015
Online Publication Date Apr 28, 2015
Publication Date Nov 1, 2015
Deposit Date Jul 13, 2016
Publicly Available Date Jul 13, 2016
Journal Environmental Microbiology
Print ISSN 1462-2912
Electronic ISSN 1462-2920
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 17
Issue 11
Public URL
Publisher URL;jsessionid=C08BE6169024674AD160797ED1F1F8F3.f03t02


Soh2015.pdf (637 Kb)

Copyright Statement
Copyright information regarding this work can be found at the following address:

You might also like

Downloadable Citations