Inhibition of Biofilm Formation

**35**

**Chapter 3**

**Abstract**

adjuvants.

**1. Introduction**

Natural Compounds Inhibiting

*Pseudomonas aeruginosa* Biofilm

*Julie Carette, Amandine Nachtergael, Pierre Duez,* 

*Mondher El Jaziri and Tsiry Rasamiravaka*

Sensing Circuitry

Formation by Targeting Quorum

The biofilm lifestyle mode certainly represents one of the most successful behaviors to facilitate bacterial survival in diverse inhospitable environments. Conversely, the ability of bacteria to develop effective biofilms represents one of the major obstacles in the fight against bacterial infections. In *Pseudomonas aeruginosa*, the biofilm formation is intimately connected to the quorum sensing (QS) mechanisms, a mode of cell-to-cell communication that allows many bacteria to detect their population density in order to coordinate common actions. In this chapter, we propose an overview (i) on *P. aeruginosa* QS mechanisms and their implication in biofilm formation, and (ii) on natural products that are known to interfere with these QS mechanisms, subsequently disrupting biofilm formation. The concluding remarks focus on perspectives of these compounds as possible antibiotherapy

**Keywords:** biofilm, *las*, natural products, PQS, *pseudomonas*, quorum sensing, *rhl*

Bacterial infections are mainly related to the ability of bacteria to invade and disseminate through their hosts by using different types of motility, by releasing a myriad of virulence factors, by building structured biofilm which lead to host cell and tissue damage but also allow bacteria to evade the immune system and conventional antimicrobial agents [1]. For decades, antibiotics, although less effective in biofilm-growing bacteria [2], have represented our best weapon against bacterial diseases. However, the on-going emergence and worldwide spreading of resistant bacteria is considerably reducing the antibiotic pallet available for the treatment of bacterial infections [3]. This alarming situation forces researchers to consider other strategies to combat bacterial infections, notably the use of phages [4] or the use of alternative agents, such as essential oils [5], silver nanoparticles [6], bacteriocins [7], and antimicrobial peptides [8]. Some interesting strategies propose original compounds that disrupt biofilm formation without affecting the viability of invading bacteria; this strategy is expected (i) to reduce the bacterial aptitude to build protective barriers, but without exerting a selective pressure *per se* [4]; (ii) to allow
