Caffeine as a Potential Quorum Sensing Inhibitor

Siti Norizan,Wai-Fong Yin,Kok-Gan Chan

doi:10.3390/s130405117

Abstract

Quorum sensing enables bacteria to control the gene expression in response to the cell density. It regulates a variety of bacterial physiological functions such as biofilm formation, bioluminescence, virulence factors and swarming which has been shown contribute to bacterial pathogenesis. The use of quorum sensing inhibitor would be of particular interest in treating bacterial pathogenicity and infections. In this work, we have tested caffeine as quorum sensing inhibitor by using Chromobacterium violaceum CV026 as a biosensor. We verified that caffeine did not degrade the N-acyl homoserine lactones tested. In this work, it is shown that caffeine could inhibit N-acyl homoserine lactone production and swarming of a human opportunistic pathogen, namely Pseudomonas aeruginosa PA01. To the best of our knowledge, this is the first documentation providing evidence on the presence of anti-quorum sensing activity in caffeine. Our work will allow caffeine to be explored as anti-infective drugs.

Highlights

Bacteria have developed a form of cell-cell communication system that allows them to communicate
As quorum sensing (QS) inhibition is focused on the interference of bacterial signaling and not antibacterial activity, it is important to ensure any anti-QS effect is not resulted from antibacterial activity
Our result (Figure 1) shown that there was no inhibition zones observed suggesting all tested concentrations of caffeine showed no antibacterial activity. This indicates that caffeine at these concentrations does not inhibit the growth of C. violaceum CV026

Summary

Introduction

Bacteria have developed a form of cell-cell communication system that allows them to communicate. This system is called the quorum sensing (QS), whereby communication within the Sensors 2013, 13 bacteria involves the production and sensing of small diffusible signal molecules produce by the bacteria. QS was first found in the marine bioluminescent bacterium Vibrio fischeri [1,2,3,4]. QS controlled various phenotypes such as biofilm formation [7,8,9,10], bioluminescence [1,2,3,4], virulence factors [11] and swarming [12,13] which has been shown contribute to bacterial pathogenesis.

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Results

Conclusion