scholarly journals The LuxS/AI-2 Quorum-Sensing System of Streptococcus pneumoniae Is Required to Cause Disease, and to Regulate Virulence- and Metabolism-Related Genes in a Rat Model of Middle Ear Infection

2018 ◽  
Vol 8 ◽  
Author(s):  
Mukesh K. Yadav ◽  
Jorge E. Vidal ◽  
Yoon Y. Go ◽  
Shin H. Kim ◽  
Sung-Won Chae ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Quorum Sensing ◽  
Middle Ear ◽  
Rat Model ◽  
Ear Infection ◽  
Sensing System ◽  
Middle Ear Infection ◽  
Quorum Sensing System

scholarly journals The LuxS-Dependent Quorum-Sensing System Regulates Early Biofilm Formation by Streptococcus pneumoniae Strain D39

2011 ◽  
Vol 79 (10) ◽  
pp. 4050-4060 ◽  
Author(s):  
Jorge E. Vidal ◽  
Herbert P. Ludewick ◽  
Rebekah M. Kunkel ◽  
Dorothea Zähner ◽  
Keith P. Klugman
Keyword(s):  
Streptococcus Pneumoniae ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Single Copy ◽  
Middle Ear Mucosa ◽  
Transcript Levels ◽  
Content Type ◽  
Sensing System ◽  
Quorum Sensing System

ABSTRACTStreptococcus pneumoniaeis the leading cause of death in children worldwide and forms highly organized biofilms in the nasopharynx, lungs, and middle ear mucosa. TheluxS-controlled quorum-sensing (QS) system has recently been implicated in virulence and persistence in the nasopharynx, but its role in biofilms has not been studied. Here we show that this QS system plays a major role in the control ofS. pneumoniaebiofilm formation. Our results demonstrate that theluxSgene is contained by invasive isolates and normal-flora strains in a region that contains genes involved in division and cell wall biosynthesis. TheluxSgene was maximally transcribed, as a monocistronic message, in the early mid-log phase of growth, and this coincides with the appearance of early biofilms. Demonstrating the role of the LuxS system in regulatingS. pneumoniaebiofilms, at 24 h postinoculation, two different D39ΔluxSmutants produced ∼80% less biofilm biomass than wild-type (WT) strain D39 did. Complementation of these strains withluxS, either in a plasmid or integrated as a single copy in the genome, restored their biofilm level to that of the WT. Moreover, a soluble factor secreted by WT strain D39 or purified AI-2 restored the biofilm phenotype of D39ΔluxS. Our results also demonstrate that during the early mid-log phase of growth, LuxS regulates the transcript levels oflytA, which encodes an autolysin previously implicated in biofilms, and also the transcript levels ofply, which encodes the pneumococcal pneumolysin. In conclusion, theluxS-controlled QS system is a key regulator of early biofilm formation byS. pneumoniaestrain D39.

scholarly journals The impact of the competence quorum sensing system on Streptococcus pneumoniae biofilms varies depending on the experimental model

2011 ◽  
Vol 11 (1) ◽  
pp. 75 ◽  
Author(s):  
Claudia Trappetti ◽  
Luciana Gualdi ◽  
Lorenzo Di Meola ◽  
Prashant Jain ◽  
Cindy C Korir ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Quorum Sensing ◽  
Experimental Model ◽  
Sensing System ◽  
Quorum Sensing System ◽  
The Impact

Viral Co-Infection Does Not Reduce the Efficacy of Vaccination against Non-Typeable Haemophilus influenzae Middle Ear Infection in a Rat Model

ORL ◽  
2001 ◽  
Vol 63 (2) ◽  
pp. 96-101 ◽  
Author(s):  
Ryka Moore ◽  
Brett A. Lidbury ◽  
Allan W. Cripps ◽  
Jennelle M. Kyd
Keyword(s):  
Haemophilus Influenzae ◽  
Middle Ear ◽  
Rat Model ◽  
Ear Infection ◽  
Middle Ear Infection

scholarly journals Salvage Eustachian Tube Cartilage Chip Insertion After Multiple Transnasal Shim Operations in Intractable Patulous Eustachian Tube

2021 ◽  
pp. 014556132199500
Author(s):  
Wei-Ting Lee ◽  
Heng-Jui Hsu
Keyword(s):  
Surgical Technique ◽  
Eustachian Tube ◽  
Middle Ear ◽  
Repeat Surgery ◽  
Ear Infection ◽  
Middle Ear Infection ◽  
Tube Lumen ◽  
Management Method ◽  
Patulous Eustachian Tube

This article presents 2 cases of extremely intractable patulous Eustachian tube following multiple transnasal shim insertion. These cases highlight the disadvantages of repeat transnasal shim operations, including enlargement of the Eustachian tube lumen, frequent dislocation, repeat surgery, recurrent middle ear infection, and shim misswallowing. The patients in these cases were successfully treated with Eustachian tube cartilage chip insertion through a postauricular approach. We describe the surgical technique and advantages of this promising management method.

Middle Ear Infection (Otitis Media)

1990 ◽  
Vol 9 (12) ◽  
pp. 936
Author(s):  
S. Michael Marcy ◽  
Michael E. Pichichero ◽  
Richard H. Schwartz
Keyword(s):  
Otitis Media ◽  
Middle Ear ◽  
Ear Infection ◽  
Middle Ear Infection

#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.

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