Screening Persisters From Clinical Bacterial Infection And Studying The Corresponding Infection Immune Mechanisms

Persisters are a bacterial groups of small subpopulation of phenotypic alienation which can tolerate treatment of fetal concentration antimicrobial drugs.The domestic and foreign scholars think they are closely related to chronic recurrent infection and bacterial biofilm infection.Klebsiella pneumoniae is an important hospital and community acquired gram-negative opportunistic pathogens that can cause a variety of diseases,such as urinary tract infections,pneumonia,bacteremia,and liver abscess.We focus on the aspect of clinic drug resistance of Klebsiella pneumonia,hope that start with microbial rapid diagnostic technology and clinical samples for persisters screening through laboratory infectious pathogen biobank,and study the mechanisms of persisters which are associated with stubborn Refractory infection.Combine with the inherent immune,mononuclear macrophage,pneumonia klebsiella bacteria interactions and mechanisms research through epidemiologicac and physiological characteristics,we investigate the immune mechanisms of infection,and hope providing a new method for further treatment about immune intervention.The first part Situation Analysis of clinical bacterial infections and molecular diagnostic testsTo analyze the clinical bacterial infection status,epidemiological investigation for medical equipment related infections;Analysis of the molecular basis of resistance to form molecular diagnostic scheme,provide early warning for clinical infection control.This research establishes on the basis of multiple PCR reaction system of microbial rapid identification and drug resistance gene detection technology,which can supplement greatly traditional microbiological methods,and better provides the basis for prevention and control of infection.The second part Screening persisters of Klebsiella pneumonia and studying the characteristicsWe take advantage of strains sample biobank in our hospital to bulid laboratory infectious pathogen biobank,and study the mechanisms of persisters and resistance.The total screening won 51 strains with bacteria,including 26 strains(48.9%)with klebsiella pneumoniae.The klebsiella pneumoniae strains are all producing ESBLs strains,100% resistant to ampicillin.Of piperacillin/TAZ,such as resistance to not more than 75%,but to ciprofloxacin resistant rate of 60.8%.Along with the higher concentrations of ciprofloxacin,withholding was declined.This group of pneumonia klebsiella bacillus were isolated from clinical withholding was clear strains can be 50 ciprofloxacin mic.This suggests that persisters cannot be distinguished through clinical conventional drug susceptibility test results,due to a lack of specific makers about persisters and difficult to distinguish and identification.It is a difficulty in the study of persisters and also a point of study.Futhermore,although the antibiotic concentration reaches a certain value in vitro which can kill the persisters,actually cannot reach such antibiotics concentration in vivo,so increasing the antibiotic concentration to kill persisters doesn't work.Therefore,we further explore the mechanisms of persistence and infection immunity,so as to provide theoretical basis for the clinical problems.The third part The mechanism research of the interaction between persisters of klebsiella pneumoniae and Mononuclear macrophagesWe study the interaction between bacteria from the aspect of infection immunity by the early screened strains of clinical persisters.Firstly,we find that the capacity of phagocytosis of Monocyte-macrophages decreased in vitro and further find out that the immune related genes expression and its effect of the signaling pathways through chip testing and bioinformatics analysis study.We find that macrophages may induce high expression SOCS-1 protein when pereisters infect macrophages,and partly dependent on TLR4 signaling pathway;SOCS-1 protein can decreses the expression of MAL and affect the activation of TLR4 signaling pathways,which is to reduce the secretion of inflammatory cytokines,like TNF-??IL-6?IL-1?.The results prove Klebsiella pneumoniae escapes the host immune attack through expression of SOCS-1 which are negative regulation of inflammatory cytokines.Our study focuses on the interaction between bacteria from the perspective of infection immunity to explain immune evasion mechanism,and provide the basis for exploring immunotherapy.