Quorum Sensing Signaling and Quenching in the Multidrug-Resistant Pathogen Stenotrophomonas maltophilia.

Pol Huedo,Isidre Gibert,Daniel Yero,Xavier Coves,Xavier Daura

doi:10.3389/fcimb.2018.00122

Abstract

Stenotrophomonas maltophilia is an opportunistic Gram-negative pathogen with increasing incidence in clinical settings. The most critical aspect of S. maltophilia is its frequent resistance to a majority of the antibiotics of clinical use. Quorum Sensing (QS) systems coordinate bacterial populations and act as major regulatory mechanisms of pathogenesis in both pure cultures and poly-microbial communities. Disruption of QS systems, a phenomenon known as Quorum Quenching (QQ), represents a new promising paradigm for the design of novel antimicrobial strategies. In this context, we review the main advances in the field of QS in S. maltophilia by paying special attention to Diffusible Signal Factor (DSF) signaling, Acyl Homoserine Lactone (AHL) responses and the controversial Ax21 system. Advances in the DSF system include regulatory aspects of DSF synthesis and perception by both rpf-1 and rpf-2 variant systems, as well as their reciprocal communication. Interaction via DSF of S. maltophilia with unrelated organisms including bacteria, yeast and plants is also considered. Finally, an overview of the different QQ mechanisms involving S. maltophilia as quencher and as object of quenching is presented, revealing the potential of this species for use in QQ applications. This review provides a comprehensive snapshot of the interconnected QS network that S. maltophilia uses to sense and respond to its surrounding biotic or abiotic environment. Understanding such cooperative and competitive communication mechanisms is essential for the design of effective anti QS strategies.

Highlights

Stenotrophomonas maltophilia is a ubiquitous multidrug resistant Gram-negative bacterium that has emerged as an important nosocomial pathogen (Brooke, 2012; Adegoke et al, 2017) and stands as one of the most common lung pathogens in cystic fibrosis patients (Amin and Waters, 2014)
It has been shown that the fatty acid (FA) cis9-octadecenoic acid synthesized by S. maltophilia strain BJ01 displays Quorum Quenching (QQ) of acyl homoserine lactone (AHL) signals resulting in antibiofilm activity on P. aeruginosa (Singh et al, 2013)
The mechanistic processes of the Diffusible Signal Factor (DSF)-quorum sensing (QS) system in the rpf -1 subpopulation seem highly similar to those reported for the DSF model organism Xanthomonas campestris pv. campestris (Xcc)

Summary

Introduction

Stenotrophomonas maltophilia is a ubiquitous multidrug resistant Gram-negative bacterium that has emerged as an important nosocomial pathogen (Brooke, 2012; Adegoke et al, 2017) and stands as one of the most common lung pathogens in cystic fibrosis patients (Amin and Waters, 2014). A distinctive feature of the DSF system in S. maltophilia is the presence of two rpf cluster variants that produce and sense DSF signals distinctly and regulate important biological processes (Huedo et al, 2014b).

Results

Conclusion