Inactivation of the rhlA gene in Pseudomonas aeruginosa prevents rhamnolipid production, disabling the protection against polymorphonuclear leukocytes
Many of the virulence factors produced by the opportunistic human pathogen Pseudomonas aeruginosa are quorum-sensing (QS) regulated. Among these are rhamnolipids, which have been shown to cause lysis of several cellular components of the human immune system, e.g. monocyte-derived macrophages and pol...
Saved in:
Published in | APMIS : acta pathologica, microbiologica et immunologica Scandinavica Vol. 117; no. 7; pp. 537 - 546 |
---|---|
Main Authors | , , , , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Oxford, UK
Oxford, UK : Blackwell Publishing Ltd
01.07.2009
Blackwell Publishing Ltd Blackwell |
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | Many of the virulence factors produced by the opportunistic human pathogen Pseudomonas aeruginosa are quorum-sensing (QS) regulated. Among these are rhamnolipids, which have been shown to cause lysis of several cellular components of the human immune system, e.g. monocyte-derived macrophages and polymorphonuclear leukocytes (PMNs). We have previously shown that rhamnolipids produced by P. aeruginosa cause necrotic death of PMNs in vitro. This raises the possibility that rhamnolipids may function as a 'biofilm shield'in vivo, which contributes significantly to the increased tolerance of P. aeruginosa biofilms to PMNs. In the present study, we demonstrate the importance of the production of rhamnolipids in the establishment and persistence of P. aeruginosa infections, using an in vitro biofilm system, an intraperitoneal foreign-body model and a pulmonary model of P. aeruginosa infections in mice. Our experimental data showed that a P. aeruginosa strain, unable to produce any detectable rhamnolipids due to an inactivating mutation in the single QS-controlled rhlA gene, did not induce necrosis of PMNs in vitro and exhibited increased clearance compared with its wild-type counterpart in vivo. Conclusively, the results support our model that rhamnolipids are key protective agents of P. aeruginosa against PMNs. |
---|---|
Bibliography: | http://dx.doi.org/10.1111/j.1600-0463.2009.02466.x ArticleID:APM2466 istex:0618655D9D1A2D5854B37BA45D3FD895D48E3207 ark:/67375/WNG-DJ0JKCB5-1 † ‡ * Contributed equally to this work. Current address: Budde Schou A/S, DK‐1601 Copenhagen V, Denmark. Current address: Department of Microbiology and Immunology, and Department of Medicine, Stanford University, California, USA. ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Article-1 ObjectType-Feature-2 Current address: Budde Schou A/S, DK-1601 Copenhagen V., Denmark. Thomas Bjarnsholt, Institute of International Health, Immunology and Microbiology, University of Copenhagen, DK-2100 Copenhagen, Denmark. tbjarnsholt@sund.ku.dk |
ISSN: | 0903-4641 1600-0463 |
DOI: | 10.1111/j.1600-0463.2009.02466.x |