Essay: Pseudomonas aeruginosa

Pseudomonas aeruginosa, the most common opportunistic pathogen is found in many environments and can cause acute or chronic infections in a range of hosts from protozoans to plants to humans(Bodey et al., 1983; Morrison and Wenzel, 1984). Meanwhile, this pathogen associated with morbidity and mortality in patients suffering from cystic fibrosis (CF), causes chronic lung infections that, 70–80% of CF patients became chronically infected with P. aeruginosa by adulthood(Aaron, 2006). In the past decade, aggressive antibiotic treatments as the major therapeutic option, has reduced the prevalence and increased the mean age of onset of chronic P. aeruginosa infection(Lee et al., 2004), however, once bacteria established chronic infection, it is difficult to eradicate even with intensive antibiotic treatment(Koch and Høiby, 2000). Meanwhile, biofilms as organized bacterial communities surrounded by an extracellular polymeric matrix, were demonstrated play an important role in physiological resistance in CF chronic lung infection(López-Causapé et al., 2014). Figure 1B shows the schematic representation of the factors contributing to inherent biofilm antimicrobial resistance. Many bacteria in clinical and natural environments are members of biofilm communities, which are assemblages of microorganisms attached to a solid surface and encased in an extracellular polymeric matrix. Advantages to being in a biofilm community include facilitation of metabolic interactions due to the cells’ close physical proximity, increased horizontal gene transfer, and protection from predation and antimicrobial stress. Currently, antibiotic regimens are unable to eradicate P. aeruginosa infections in CF airways(Römling et al., 1994). This lack of treatment efficacy is believed to be due in part to the formation of antibiotic resistant biofilms forming in the CF lungs(Costerton et al., 1999). The ability of P. aeruginosa to grow and establish drug resistant biofilms in the lungs of CF patients is thought to be facilitated by the hypersecretion of a viscous mucus layer in the CF airway. Thus, better understanding of the mechanisms used by P. aeruginosa to form matured biofilms to circumvent host defenses and therapeutic intervention strategies is critical for advancing novel treatment strategies is very important. Currently, some studies about the evolution of P. aeruginosa in chronic infections has been well organized by Anders Folkesson et al in 2012(Folkesson et al., 2012). However, the evolution and adaption process of Pseudomonas aeruginosa biofilms was poorly understand. Base on the special roles of P. aeruginosa biofilms in chronic infection, some literatures has clearly described the role of P. aeruginosa biofilms in antimicrobial resistance(Ciofu et al., 2014; López-Causapé et al., 2014). In fact, biofilm formation as a developmental progression that involves a number of complex and highly regulated processes, has been well known(O’Toole et al., 2000) (Fig. 1C). Meanwhile, Sophie MM et al(Costerton et al., 1999) well described the components of P. aeruginosa biofilms in 2008. Biofilms are intricate bacterial communities found attached to living or abiotic surfaces and surrounded by a bacterially-produced extracellular matrix composed of exopolysaccharides, DNA and proteins. Meanwhile, they also mentioned study the fresh biofilms form from the CF patient are not yet possible because of the limitation of lung …