Quorum Sensing and its Relevance to Infectious Diseases

Donabedian, Haig

doi:10.1053/jinf.2002.1120

Cited by 84 publications

(50 citation statements)

References 52 publications

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“…This bacterium regulates most of its virulence determinants in a cell-density-dependent manner via a mechanism called quorum-sensing (QS). Such global regulatory systems are found in most bacterial species, and control several and diverse biological functions, such as virulence, bacterial conjugation, bioluminescence and biofilm formation (de Kievit & Iglewski, 2000;Donabedian, 2003;Loh et al, 2002;Miller & Bassler, 2001). QS is mediated by diffusible signalling molecules released into the external environment.…”

Section: Introductionmentioning

confidence: 99%

Revisiting the quorum-sensing hierarchy in Pseudomonas aeruginosa: the transcriptional regulator RhlR regulates LasR-specific factors

2009

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Pseudomonas aeruginosa uses the two major quorum-sensing (QS) regulatory systems las and rhl to modulate the expression of many of its virulence factors. The las system is considered to stand at the top of the QS hierarchy. However, some virulence factors such as pyocyanin have been reported to still be produced in lasR mutants under certain conditions. Interestingly, such mutants arise spontaneously under various conditions, including in the airways of cystic fibrosis patients. Using transcriptional lacZ reporters, LC/MS quantification and phenotypic assays, we have investigated the regulation of QS-controlled factors by the las system. Our results show that activity of the rhl system is only delayed in a lasR mutant, thus allowing the expression of multiple virulence determinants such as pyocyanin, rhamnolipids and C 4 -homoserine lactone (HSL) during the late stationary phase. Moreover, at this stage, RhlR is able to overcome the absence of the las system by activating specific LasR-controlled functions, including production of 3-oxo-C 12 -HSL and Pseudomonas quinolone signal (PQS). P. aeruginosa is thus able to circumvent the deficiency of one of its QS systems by allowing the other to take over. This work demonstrates that the QS hierarchy is more complex than the model simply presenting the las system above the rhl system.

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Section: Introductionmentioning

confidence: 99%

Revisiting the quorum-sensing hierarchy in Pseudomonas aeruginosa: the transcriptional regulator RhlR regulates LasR-specific factors

2009

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“…These acyl-HSLs are hierarchically regulated in that threshold levels of 3OC12-HSL are required to activate C4-HSL production (11,12). The 3OC12-HSL and C4-HSL signals regulate hundreds of genes in P. aeruginosa, control the production of a battery of extracellular virulence factors, and play a role in biofilm development (6,8,(13)(14)(15)(16).…”

mentioning

confidence: 99%

Inactivation of a Pseudomonas aeruginosa quorum-sensing signal by human airway epithelia

Chun

Ozer

Welsh

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

268

181

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Mammalian airways protect themselves from bacterial infection by using multiple defense mechanisms including antimicrobial peptides, mucociliary clearance, and phagocytic cells. We asked whether airways might also target a key bacterial cell-cell communication system, quorum-sensing. The opportunistic pathogen Pseudomonas aeruginosa uses two quorum-sensing molecules, N-(3-oxododecanoyl)-L-homoserine lactone (3OC12-HSL) and Nbutanoyl-L-homoserine lactone (C4-HSL), to control production of extracellular virulence factors and biofilm formation. We found that differentiated human airway epithelia inactivated 3OC12-HSL. Inactivation was selective for acyl-HSLs with certain acyl side chains, and C4-HSL was not inactivated. In addition, the capacity for inactivation varied widely in different cell types. 3OC12-HSL was inactivated by a cell-associated activity rather than a secreted factor. These data suggest that the ability of human airway epithelia to inactivate quorum-sensing signal molecules could play a role in the innate defense against bacterial infection.

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“…Bir bakteri bu sinyallerle çevreden aldığı uyarılara cevap geliştirir ve metabolizmasını çevresel faktörlere göre düzenleyerek ortama uyum sağlamaya çalışır (24). Bakteriler bu sistemle çevrelerinde bulunan bakterilerin yoğunluğunu algılar (24,25).…”

Section: Biyofilm Yapısı Ve Oluşumuunclassified

“…Yöntemlerin her birinin avantaj ve dezavantajları mevcuttur. Çalışmalardan elde edilen genel kanı, kullanım kolaylığı, ucuz olması, kısa sürede sonuç alına-bilmesi ve birçok farklı bakteri ve tedavi rejiminin değerlendi-rilebilmesi nedeniyle mikroplak yönteminin tarama yöntemi olarak seçilmesinin uygun olacağıdır (24,54,55). Geleneksel olarak, klinik mikrobiyoloji laboratuvarları planktonik yani serbest çoğalan mikroorganizmaları kültürde üretmeye odaklanmıştır.…”

Section: Diyabetik Ayak Yaralarında Biyofilm Etkileriunclassified

Biofilm and Diabetic Foot Infections

Vatan¹,

Saltoğlu²

2017

Klimik Dergisi

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Biofilm is a well known issue with increasing importance, especially in the field of medicine. The biofilm formation is usually observed in foreign body infections as well as chronic wound infections. The diabetic foot ulcer is suitable for biofilm formation due to its rich wound exudate and debris content and impaired host immune response. The diabetic foot infection has emerged as one of the most important causes of mortality and morbidity in diabetes mellitus which needs special efforts to eradicate infection due to high rate of biofilm formation. In this review, we discuss the characteristic features of biofilms and the importance of the biofilm formation in diabetic foot infections. We also highlight the diagnosis and management of the biofilm formation.

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Quorum Sensing and its Relevance to Infectious Diseases

Cited by 84 publications

References 52 publications

Revisiting the quorum-sensing hierarchy in Pseudomonas aeruginosa: the transcriptional regulator RhlR regulates LasR-specific factors

Revisiting the quorum-sensing hierarchy in Pseudomonas aeruginosa: the transcriptional regulator RhlR regulates LasR-specific factors

Inactivation of a Pseudomonas aeruginosa quorum-sensing signal by human airway epithelia

Biofilm and Diabetic Foot Infections

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