Study On Rapid Detection System And Molecular Epidemiology Of Staphylococcus Aureus

Staphylococcus aureus(S.aureus)is a common human infection pathogen which can cause skin and soft tissue infection,food poisoning,toxic shock syndrome,artificial devices associated infection,urinary tract infection,arthritis as well as lead to serious illness,life-threatening blood infections,endocarditis,pericarditis,pneumonia,etc..From the latter half of the last century,Staphylococcus aureus,especially Methicillin-Resistant Staphylococcus aureus(MRSA)infection is a serious threat to human health.How to detect pathogens quickly and accurately with mastering the epidemic regularity of Staphylococcus aureus is a great significance for the control of nosocomial infection and the rational use of drugs.Objective:1.To investigate medical expenses caused by the preliminary inquiry of Staphylococcus aureus infection and hospitalization due to prolonged hospital stay,increased understanding of Staphylococcus aureus infection of the disease burden for subsequent research to provide health economics basis and background.2.To construct the system for rapid diagnosis of Staphylococcus aureus by using multiple probe pathogen melting curve analysis technology which compared with the traditional detection technology in order to improve the detection of Staphylococcus aureus sensitivity and accuracy.3.To preliminarily analyse Staphylococcus aureus isolates from Zhongshan Affiliated Hospital of Xiamen University on clinical antimicrobial drug resistance,drug resistant phenotype,and to guide clinical medication and to explore for molecular typing provides supplementary evidence.4.To grasp the distribution situation about the Staphylococcus aureus isolated from Zhongshan Affiliated Hospital of Xiamen University with three molecular typing methods.5.To detect the virulence of PVL,TSST-1 and Sas-X in clinical isolates of Staphylococcus aureus from Zhongshan Affiliated Hospital of Xiamen University.Method:1.Through clinical information retrieval system,Staphylococcus aureus infection cases in hospitalized patients within nearly three years from Zhongshan Affiliated Hospital of Xiamen University,compared with manual tracing,Staphylococcus aureus infection case group and control group in medical expenses and hospitalization in different areas,increase caused by the infection of gold revealed Staphylococcus aureus disease burden.2.Staphylococcus aureus strains with the multiple melting curve analysis technique for rapid detection of validation were collected,and compared with the traditional detection methods,in order to find a new rapid detection method with more advantages.3.Used K-B paper method to detect the resistance of Staphylococcus aureus to 18 commonly used antibiotics and analyze the drug resistance phenotype(Vancomycin:Broth dilution method).4.Respectively by pulsed field gel electrophoresis(PFGE),multilocus sequence typing(MLST)and multiple melting analysis(MLMT)of Staphylococcus aureus genotypes of clinical isolates of Zhongshan Affiliated Hospital of Xiamen University,and used BioNumerics and Phyloviz software to analyze the homology.5.PCR method was used to detect the virulence of PVL,TSST-1 and Sas-X genes of 426 Staphylococcus aureus.Result:1.In this study,cases group average medical expenses of Staphylococcus aureus infection(median)is 19728.41 yuan,the number of hospitalization days(median 14 days),control group average treatment cost(median)is 9345.23 yuan,hospitalization days(median)was 9 days,with an average increase of medical expenses 10383.18 yuan,prolonged 5-days hospital stay;Considering Staphylococcus aureus infection caused by the disease burden is the difference between different age groups and departments at the same time,the bacteria infection is on the basis of the improvement of disease has a negative impact.2.The system of“Multiple Melting Curve Analysis”technology in accuracy,sensitivity,specificity,and consistency is better than the traditional method for rapid detection of pathogenic bacteria in 2 developed by our research group,and in time,the new method will be shorter than the traditional method,the high detection efficiency.3.A total of 426 strains of Staphylococcus aureus were collected in this study.Among them,281 strains(68.59%)were Methicillin-Resistant Staphylococcus aureus(MRSA).The strains showed resistant to 8 antibiotics(>50%)and there was a serious problem of multiple drug resistance(about 70.19%)in all of the commonly used antibiotics in clinic.The resistance of methicillin resistant Staphylococcus aureus and methicillin sensitive Staphylococcus aureus were different.In addition,426 strains of Staphylococcus aureus were divided into PFGE(100%).Randomly selected from the 108 representative isolates by can be clustered into 14 gene clusters,of which the main type is C8,CIO and C11(89.67%).MLMT,the classification of the strains was divided into 20 types.The main type were MT1-MT5(87.09%);MLST would be the 108 representative isolates were divided into 25 ST,the popular type is ST239,ST59,ST188,three types of methods in the main epidemiological type is the same,and the accuracy of classification is better than single method is more accurate,molecular typing and drug resistance phenotype was similar to a certain extent.4.Among the strains collected in this study(11.03%)carried PVL virulence genes,and 21 strains(4.93%)carried TSST-1 virulence genes,but no Sa.s-X virulence genes were found.The results showed that the 21 strains carrying TSST-I gene were MRSA,and there were 20 strains carrying PVL gene and gene carrying TSST-1 gene and PVL gene.The resistance rate of MRSA to the commonly used antibiotics was 100%.Conclusion:Staphylococcus aureus is a common pathogen of nosocomial infection in Zhongshan Affiliated Hospital of Xiamen University,which leads to the increase of the cost of hospitalization,the difficulty of the treatment of basic diseases and the decrease of the turnover of hospital beds.As a common pathogen of nosocomial infection,we used multiple-melting-curve analysis technology,accelerate the pathogen detection rate,and at the same time whether the identification of methicillin resistant Staphylococcus aureus.The drug resistance of Staphylococcus aureusisis more serious,and the distribution of strains in isolation in the main,there are several types of epidemic situation,the possible outbreak of infection seriously.In addition,the current Zhongshan Affiliated Hospital of Xiamen University and detect the strains carrying MRSA TSST-1 gene and PVL gene occupies a certain proportion in the clinical,so the clinical should be caused by the infection and outbreak caused by a high degree of attention,at the same time,we should further study with pathotoxin of Staphylococcus aureus pathogenicity and clinical distribution characteristics and provide a theoretical basis for clinical treatment.