#99: Streptococcus pyogenes Utilizes the Peptide-Based Rgg 2/3 Quorum Sensing System During Oropharyngeal Colonization

2021 ◽  
Vol 10 (Supplement_1) ◽  
pp. S10-S10
Author(s):  
Artemis Gogos ◽  
Michael J Federle
Keyword(s):  
Quorum Sensing ◽  
Streptococcus Pyogenes ◽  
Lymphoid Tissue ◽  
Transcriptional Activator ◽  
Rt Pcr ◽  
Sensing System ◽  
Bacterial Rna ◽  
Quorum Sensing System ◽  
Luciferase Reporters

Abstract Background Streptococcus pyogenes is a human-restricted pathogen most often found in the human nasopharynx. Multiple bacterial factors have been found to contribute to persistent colonization of this niche, and many of these factors are important in mucosal immunity and vaccine development. In this work, we infected mice intranasally with transcriptional regulator mutants of the Rgg2/3 quorum sensing (QS) system—a peptide-based signaling system conserved in all sequenced isolates of S. pyogenes. Methods Three-week-old CD1 mice were intranasally infected with ~107 CFU of S. pyogenes strain MGAS315. Calcium alginate throat swabs were used to monitor nasopharyngeal colonization by the bacteria over time. Luciferase reporters used alongside an IVIS camera were able to show quorum sensing activity levels after inoculation into the mouse nose. Bacterial RNA was isolated from the throat of the mice and quantitative RT–PCR was performed on the samples to corroborate the luciferase reporter data. The nasal-associated lymphoid tissue (NALT) was excised and its supernatants were subjected to 32-plex murine cytokine and chemokine analysis (Millipore). Results Deletion of the QS system’s transcriptional activator (Δrgg2) dramatically diminished the percentage of colonized mice. Deletion of the transcriptional repressor (Δrgg3) increased the percentage of colonized mice compared with wild type. Stimulation of the QS system using synthetic pheromones prior to inoculation did not significantly increase the percentage of animals colonized, indicating that activity of the QS system is responsive to conditions of the host nasopharynx. Mice inoculated with QS-dependent luciferase reporters were subjected to in vivo imaging and showed activation within 1 hour. Bacterial RNA extracted directly from oropharyngeal swabs and evaluated by quantitative RT–PCR subsequently confirmed QS upregulation within 1 hour of inoculation. In the nasal-associated lymphoid tissue (NALT), a muted inflammatory response to the Δrgg2 bacteria suggests that their rapid elimination fails to elicit the previously characterized response to intranasal inoculation of GAS. Conclusions Deletion of the Rgg2 transcriptional activator of the Rgg 2/3 quorum sensing system eliminates colonization of the murine nasopharynx and changes the transcriptional profile of the bacteria in this niche. An existing small-molecule inhibitor of the Rgg2/3 system was unable to inhibit QS activation in vivo, likely due to the suboptimal achievable doses; however, results of our study indicate inhibition of QS may diminish the oropharyngeal colonization of S. pyogenes and argue for further development.

scholarly journals Colonization of the murine oropharynx by Streptococcus pyogenes is governed by the Rgg2/3 quorum sensing system

2020 ◽  
Author(s):  
Artemis Gogos ◽  
Michael J. Federle
Keyword(s):  
Quorum Sensing ◽  
Streptococcus Pyogenes ◽  
Vaccine Development ◽  
Wide Spectrum ◽  
Regulatory System ◽  
Transcriptional Activator ◽  
Upper Respiratory Tract ◽  
Sensing System ◽  
Molecular Therapeutics ◽  
Quorum Sensing System

AbstractStreptococcus pyogenes is a human-restricted pathogen most often found in the human nasopharynx. Multiple bacterial factors are known to contribute to persistent colonization of this niche, and many are important in mucosal immunity and vaccine development. In this work, mice were infected intranasally with transcriptional regulator mutants of the Rgg2/3 quorum sensing (QS) system—a peptide-based signaling system conserved in sequenced isolates of S. pyogenes. Deletion of the QS system’s transcriptional activator (Δrgg2) dramatically diminished the percentage of colonized mice while deletion of the transcriptional repressor (Δrgg3) increased the percentage of colonized mice compared to wild type. Stimulation of the QS system using synthetic pheromones prior to inoculation did not significantly increase the percentage of animals colonized, indicating that QS-dependent colonization is responsive to the intrinsic conditions within the host upper respiratory tract. Bacterial RNA extracted directly from oropharyngeal swabs and evaluated by quantitative RT-PCR subsequently confirmed QS upregulation within one hour of inoculation. In the nasal-associated lymphoid tissue (NALT), a muted inflammatory response to the Δrgg2 bacteria suggests that their rapid elimination failed to elicit the previously characterized response to intranasal inoculation of GAS. This work identifies a new transcriptional regulatory system governing the ability of S. pyogenes to colonize the nasopharynx and provides knowledge that could help lead to decolonization therapeutics.Author SummaryStreptococcus pyogenes is responsible for a wide spectrum of diseases ranging from common pharyngitis to infrequent invasive infections like necrotizing fasciitis. The ability of this microorganism to persist in the human oropharynx predisposes colonized individuals to a variety of superficial and invasive diseases which lead to significant morbidities and mortality. Identification of the regulatory systems that augment the bacteria’s ability to colonize the oropharynx provides potential targets against which molecular therapeutics can be designed. Here we show that the Rgg2/3 quorum sensing system, an interbacterial communication system, governs the ability of S. pyogenes to colonize the murine oropharynx. Disruption of the system’s transcriptional activator reduced colonization dramatically, eliminated the transcription of two sets of genes known to be activated by the Rgg2/3 system, and tempered the innate immune response seen when S. pyogenes is intranasally infected into the mouse.

scholarly journals The Enterococcus faecalis fsrB Gene, a Key Component of the fsr Quorum-Sensing System, Is Associated with Virulence in the Rabbit Endophthalmitis Model

2002 ◽  
Vol 70 (8) ◽  
pp. 4678-4681 ◽  
Author(s):  
Eleftherios Mylonakis ◽  
Michael Engelbert ◽  
Xiang Qin ◽  
Costi D. Sifri ◽  
Barbara E. Murray ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Enterococcus Faecalis ◽  
Deletion Mutant ◽  
Wild Type ◽  
Sensing System ◽  
Quorum Sensing System

ABSTRACT We used a rabbit endophthalmitis model to explore the role of fsrB, a gene required for the function of the fsr quorum-sensing system of Enterococcus faecalis, in pathogenicity. A nonpolar deletion mutant of fsrB had significantly reduced virulence compared to wild type. Complementation of mutation restored virulence. These data corroborate the role of fsrB in E. faecalis pathogenesis and suggest that the rabbit endophthalmitis model can be used to study the in vivo role of quorum sensing.

scholarly journals Thymol Protects Channel Catfish from Aeromonas hydrophila Infection by Inhibiting Aerolysin Expression and Biofilm Formation

2020 ◽  
Vol 8 (5) ◽  
pp. 636 ◽  
Author(s):  
Jing Dong ◽  
Lushan Zhang ◽  
Yongtao Liu ◽  
Ning Xu ◽  
Shun Zhou ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Channel Catfish ◽  
Aeromonas Hydrophila ◽  
Biofilm Formation ◽  
Cell Injury ◽  
Opportunistic Pathogen ◽  
Protective Effects ◽  
Sensing System ◽  
Quorum Sensing System

Aeromonas hydrophila is an opportunistic pathogen responsible for a number of diseases in freshwater farming. Moreover, the bacterium has been identified as a zoonotic pathogen that threatens human health. Antibiotics are widely used for treatments of infectious diseases in aquaculture. However, the abuse of antibiotics has led to the emergence of antimicrobial resistant strains. Thus, novel strategies are required against resistant A. hydrophila strains. The quorum sensing (QS) system, involved in virulence factor production and biofilm formation, is a promising target in identifying novel drugs against A. hydrophila infections. In this study, we found that thymol, at sub-inhibitory concentrations, could significantly reduce the production of aerolysin and biofilm formation by inhibiting the transcription of genes aerA, ahyI, and ahyR. These results indicate that thymol inhibits the quorum sensing system. The protective effects of thymol against A. hydrophila mediated cell injury were determined by live/dead assay and lactate dehydrogenase (LDH) release assay. Moreover, the in vivo study showed that thymol could significantly decrease the mortality of channel catfish infected with A. hydrophila. Taken together, these findings demonstrate that thymol could be chosen as a phytotherapeutic candidate for inhibiting quorum sensing system-mediated aerolysin production and biofilm formation in A. hydrophila.

scholarly journals The hanR/hanI quorum-sensing system of Halomonas anticariensis, a moderately halophilic bacterium

Microbiology ◽  
2011 ◽  
Vol 157 (12) ◽  
pp. 3378-3387 ◽  
Author(s):  
Ali Tahrioui ◽  
Emilia Quesada ◽  
Inmaculada Llamas
Keyword(s):  
Quorum Sensing ◽  
Halophilic Bacterium ◽  
Transcriptional Analysis ◽  
Signal Molecules ◽  
Rt Pcr ◽  
Significant Group ◽  
Signalling Molecules ◽  
Sensing System ◽  
Moderately Halophilic Bacterium ◽  
Quorum Sensing System

Quorum sensing is a cell density-dependent gene expression mechanism found in many Gram-negative bacteria which involves the production of signal molecules such as N-acylhomoserine lactones (AHLs). One significant group of micro-organisms in which quorum sensing has not been previously studied, however, are the moderate halophiles. We describe here the results of our studies of the quorum-sensing system in Halomonas anticariensis FP35T, which is composed of luxR/luxI homologues: hanR (the putative transcriptional regulator gene) and hanI (the autoinducer synthase gene). To understand how the hanR/hanI system is organized and regulated we conducted RT-PCR and quantitative real-time PCR assays. Transcriptional analysis indicated that the hanR and hanI genes are on the same transcript and that their transcription is growth phase-dependent. HanI seems to be the only autoinducer synthase responsible for the synthesis of AHLs by the bacterium, since the inactivation of hanI resulted in the complete loss of its AHLs. We also found that the hanI gene appears to be transcribed from its own promoter and that its expression does not depend upon HanR. This finding was supported by the fact that the FP35hanR mutant showed AHL-producing activity and hanI expression similar to that of the wild-type strain, the latter being measured by RT-PCR. Moreover, hanR is expressed from its own promoter and appears to be independent of the AHL signalling molecules produced by HanI.

scholarly journals Specificity and Genetic Polymorphism of theBacillus Competence Quorum-Sensing System

2001 ◽  
Vol 183 (2) ◽  
pp. 451-460 ◽  
Author(s):  
P. Tortosa ◽  
L. Logsdon ◽  
B. Kraigher ◽  
Y. Itoh ◽  
I. Mandic-Mulec ◽  
...  
Keyword(s):  
Genetic Polymorphism ◽  
Quorum Sensing ◽  
Response Regulator ◽  
Two Component System ◽  
Extracellular Medium ◽  
Receptor Proteins ◽  
Sensing System ◽  
Quorum Sensing System ◽  
Isogenic Strains

ABSTRACT A quorum-sensing mechanism involving the pheromone ComX and the ComP-ComA two-component system controls natural competence inBacillus subtilis. ComX is expressed as a cytoplasmic inactive precursor that is released into the extracellular medium as a cleaved, modified decapeptide. This process requires the product ofcomQ. In the presence of ComX, the membrane-localized ComP histidine kinase activates the response regulator ComA. We compared the sequences of the quorum-sensing genes from four closely related bacilli, and we report extensive genetic polymorphism extending throughcomQ, comX, and the 5′ two-thirds ofcomP. This part of ComP encodes the membrane-localized and linker domains of the sensor protein. We also determined the sequences of the comX genes of four additional wild-type bacilli and tested the in vivo activities of all eight pheromones on isogenic strains containing four different ComP receptor proteins. A striking pattern of specificity was discovered, providing strong evidence that the pheromone contacts ComP directly. Furthermore, we show that coexpression of comQ and comX inEscherichia coli leads to the production of active pheromone in the medium, demonstrating that comQ is the only dedicated protein required for the processing, modification, and release of active competence pheromone. Some of the implications of these findings for the evolution and the mechanism of the quorum-sensing system are discussed.

scholarly journals Specificity and Polymorphism of the PlcR-PapR Quorum-Sensing System in the Bacillus cereus Group

2005 ◽  
Vol 187 (3) ◽  
pp. 1182-1187 ◽  
Author(s):  
Leyla Slamti ◽  
Didier Lereclus
Keyword(s):  
Quorum Sensing ◽  
Bacillus Cereus ◽  
Transcriptional Regulator ◽  
Bacillus Cereus Group ◽  
Sensing System ◽  
Quorum Sensing System ◽  
A Cell ◽  
Processed Form ◽  
Is Strain

ABSTRACT The expression of extracellular virulence factors in various species of the Bacillus cereus group is controlled by the plcR and papR genes, which encode a transcriptional regulator and a cell-cell signaling peptide, respectively. A processed form of PapR, presumably a pentapeptide, specifically interacts with PlcR to facilitate its binding to its DNA targets. This activating mechanism is strain specific, with this specificity being determined by the first residue of the pentapeptide. We carried out in vivo complementation assays and compared the PlcR-PapR sequences of 29 strains from the B. cereus group. Our findings suggested that the fifth amino acid of the pentapeptide is also involved in the specificity of activation. We identified four classes of PlcR-PapR pairs, defining four distinct pherotypes in the B. cereus group. We used these findings to look at the evolution of the PlcR-PapR quorum-sensing system with regard to the phylogeny of the species forming the B. cereus group.

scholarly journals Complete Genome Sequence of Streptococcus pyogenesemm14 JS95, a Necrotizing Fasciitis Strain Isolated in Israel

2017 ◽  
Vol 5 (11) ◽  
Author(s):  
Jacqueline L. Y. Chee ◽  
Miriam Ravins ◽  
Emanuel Hanski ◽  
Swaine L. Chen
Keyword(s):  
Quorum Sensing ◽  
Necrotizing Fasciitis ◽  
Genome Sequence ◽  
Streptococcus Pyogenes ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Content Type ◽  
Sensing System ◽  
Quorum Sensing System

ABSTRACT Here, we report the complete genome sequence of the Streptococcus pyogenes emm14 strain JS95, isolated from a patient with necrotizing fasciitis. The streptococcal invasion locus (sil), the first quorum-sensing system characterized in S. pyogenes, was identified in this strain.

Sign in / Sign up

Export Citation Format

Share Document