Detection of Quorum Sensing Signal Molecules and Identification of an Autoinducer Synthase Gene among Biofilm Forming Clinical Isolates of Acinetobacter spp.

Anbazhagan, Deepa and Mansor, Marzida and Ong, Gracie Siok Yan and Yusof, Mohd Yasim Mohd and Hassan, Hamimah and Sekaran, Shamala Devi (2012) Detection of Quorum Sensing Signal Molecules and Identification of an Autoinducer Synthase Gene among Biofilm Forming Clinical Isolates of Acinetobacter spp. PLoS ONE, 7 (7). e36696. ISSN 1932-6203

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Official URL: https://doi.org/10.1371/journal.pone.0036696

Abstract

Background: Quorum sensing is a term that describes an environmental sensing system that allows bacteria to monitor their own population density which contributes significantly to the size and development of the biofilm. Many gram negative bacteria use N-acyl-homoserine lactones as quorum sensing signal molecules. In this study, we sought to find out if the biofilm formation among clinical isolates of Acinetobacter spp. is under the control of autoinducing quorum sensing molecules. Methodology/Principal Findings: Biofilm formation among clinical isolates of Acinetobacter spp. was assessed and the production of signal molecules were detected with Chromobacterium violaceum CV026 biosensor system. Characterisation of autoinducers was carried out by mass spectrometric analysis. We have also reported the identification of an autoinducer synthase gene, abaΙ among the isolates that produce quorum sensing signal molecules and have reported that the mutation in the abaI gene influences their biofilm forming capabilities. Using a microtitre-plate assay it was shown that 60% of the 50 Acinetobacter spp. isolates significantly formed biofilms. Further detection with the biosensor strain showed that some of these isolates produced long chain signal molecules. Mass spectrometric analysis revealed that five of these isolates produced N-decanoyl homoserine lactone and two isolates produced acyl-homoserine lactone with a chain length equal to C12. The abaΙ gene was identified and a tetracycline mutant of the abaΙ gene was created and the inhibition in biofilm formation in the mutant was shown. Conclusions/Significance: These data are of great significance as the signal molecules aid in biofilm formation which in turn confer various properties of pathogenicity to the clinical isolates including drug resistance. The use of quorum sensing signal blockers to attenuate bacterial pathogenicity is therefore highly attractive, particularly with respect to the emergence of multi antibiotic resistant bacteria.

Item Type: Article
Additional Information: Department of Medical Microbiology, Faculty of Medicine Building, University of Malaya, 50603 Kuala Lumpur, MALAYSIA
Uncontrolled Keywords: Medical Microbiology
Subjects: R Medicine
Divisions: Faculty of Medicine
Depositing User: hamimah hamimah hassan
Date Deposited: 07 Aug 2012 01:15
Last Modified: 03 Dec 2019 07:51
URI: http://eprints.um.edu.my/id/eprint/3558

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