Journal of Molecular Biology
ReviewPseudomonas aeruginosa Biofilm Infections: Community Structure, Antimicrobial Tolerance and Immune Response
Graphical abstract
Pseudomonas aeruginosa biofilm in a chronic wound. The presence of the biofilm causes inflammation and is thought to keep the wound in an inflammatory that prevents healing. The arrows point to the wound surface. The scale bar corresponds to 30 μm.
Introduction
Infections caused by microbial biofilms are a significant socioeconomic burden that implicates hospitalization, patient suffering, lost employment and reduced life quality [1]. Because the use of conventional antimicrobial compounds in many cases cannot eradicate biofilm infections [2], there is an urgent need to develop alternative measures to combat biofilms. Novel anti-biofilm strategies require detailed knowledge about the biology of biofilms, and accordingly, research on biofilm infection microbiology, biofilm formation mechanisms and biofilm-associated antimicrobial tolerance has come to the fore during the last two decades. In the present article, we review some of this research with a focus on the biofilm model organism Pseudomonas aeruginosa.
Section snippets
Human Biofilm Infections
Research performed in the last decades has made it clear that biofilms are the underlying cause of a variety of tissue-associated and implant-associated infections. Human biofilm infections include (but are not limited to) dental caries, periodontitis, otitis media, cystic fibrosis (CF) pneumonia, chronic sinusitis, chronic wound infections, musculoskeletal infections, necrotizing fasciitis, biliary tract infection, osteomyelitis, bacterial prostatitis, native valve endocarditis, melioidosis,
Biofilms in Animal Models
Animal infection models are increasingly used to gain insights into the biology of biofilm infections and in efforts to develop novel efficient biofilm treatment strategies. In the following, some of the animal biofilm infection model work where P. aeruginosa has been used as the infecting agent is described.
Biofilm Biology in In Vitro Experimental Setups
In order to develop efficient treatments against biofilm infections, we need knowledge about biofilm formation mechanisms and the mechanisms underlying the tolerance of biofilms toward antimicrobial treatment and immune responses. Most of the current knowledge concerning biofilm formation by P. aeruginosa and the physiological properties associated with this sessile mode of growth has been obtained from studying biofilms in in vitro experimental setups.
Final Remarks
In the last decade, we have gained much knowledge about the molecular biology of in vitro-grown biofilms, whereas knowledge about the molecular biology of biofilm infections is lacking. Based on our present knowledge, a number of strategies to fight P. aeruginosa biofilm infections have been suggested, for example, lowering of the bacterial c-di-GMP level via DGC inhibition to prevent or resolve biofilms, blocking of QS to decrease tolerance toward the immune system and antimicrobials and
Acknowledgements
This work was supported by a grant from the Danish Council for Independent Research, DFF–1323-00177.
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