Studies On The Pathogenicity Of Clinical Isolates Of Pseudomonas Aeruginosa And Its Relationship With The Quorum Sensing System

Objective This paper studied the pathogenic capabilities of clinical wild PA strains and probed the relationship between the QS system and the pathogenicity of PA from a clinical point of view. New information for group control theory of the QS system, first-hand material for clinical control of PA infection, toy and to new strategies for clinical control of PA infection are provided in this study.Methods By using the characteristics and countermeasures of PA clinical infection as the research direction, and clinically isolated PA strains as the research objects, we,,analyzed the distribution characteristics and drug resistance of PA clinical infection, we also tested changes of PA virulence factors expression upon the QS system failure. The encoding gene mutation features of QS system and the regulation mechanisms of QS system to virulence factors were also investigated.Results 1. The drug resistance and clinical distribution of PA in the Wuhan region are consistent with results reported by other researches.2. In 84 clinical isolated PA strains, most (95.34%) show normal QS system.. We have screened out four QS defective strains (4.76%).3. The expressions of various virulence factors of these defective strains are all defective to different extent, and QS system control strictly or partially the pathogenesis of PA.. Elastase secretion is strictly regulated by the QS system. Pyocyanine secretion, bacteria biofilm formation and swimming ability are regulated by QS system 4. RHL system plays an important role in the secretion of pyocyanine. Biofilm formation and swimming ability are also regulated by RHL system.5. PA QS system exists highly mutation-prone region. The coding genes of local PA QS system are not identical with those of wild standard strains.Conclusion 1. The functions of QS system in most clinically isolated PA strains is normal, and it suggests that QS system plays an important role in the process of clinical PA infection. Interference with QS system could be a very promising new treatment, which deserves further study.2. The pathogenic ability of QS defective strains flaws, but they can still establish infections. The defection of QS system doesn not completely disable the pathogenesis. Interfering with PA QS system cannot completely remove bacterial infection, and the bacteria can survive through all the favorable elements, and to control PA infection may need to use a combination of all kinds of means.3.The strength of PA pathogenic ability is regulated by a complex network including the QS system. The effect of the individual differences in the host, internal environment factors, and the immune function cannot be ignored when PA establishes infections.4.The encode gene of QS system exits a highly mutational area.