Clinical Analysis Of Patients With Pneumonia Caused By Methicillin-resistant Staphylococcus Aureus

Objectives:This study had analyzed the drug resistance condition and clinical data of patients with pneumoniai caused by MRSA,which were compared with patients infected by Methicillin-resistant Staphylococcus aureus at the same period of hospitalization.Therefore,we study the clinical data of MRSA patients in our hospital,of which we analyse deeply to study the MICs of MRSA,the susceptible and risk factors of patients.To provide scientific basis for better prevention,guiding clinical medication,we evaluated the prognosis of patients with MRSA pneumonia.Methods:(1)The strains of Staphylococcus aureus identified and isolated from our hospital from January 2013 to September 2016 in our hospital were collected,the drug resistance of these strains were analyzed in order to master the prevalence of MRSA infection.(2)According to the diagnosis of MRSA pneumonia,72 cases were regarded as the study group and 72 patients with MSSA pneumonia were selected as the control group,which were collected at the same period of hospitalization.This research carried out as follows:1.The 4-year isolation rate of MRSA in our hospital was analyzed retrospectively.2.The 4-year resistant rate and MIC values of MRSA strains isolated from patients with pneumonia caused by MRSA were analyzed retrospectively in the past 4 years.3.MRSA and MSSA patients were taken as the research object.General condition,underlying diseases,the hospitalization time before isolation,with or without invasive operation,ICU admission,days of mechanical ventilation and and the antibiotic use before isolation were compared respectively,to explore the susceptible factors of patients with MRSA pneumonia.4.According to the prognosis of the patients,72 cases of MRSA pneumonia were categorized as survival group(n=43)and death group(n=29).General information,underlying diseases,and relevant laboratory examinations within 24 hours(including:peripheral white blood cell count,hemoglobin,C-reactive protein and procalcitonin,albumin,blood glucose,serum potassium,blood uric acid,creatinine,alanine aminotransferase,aspartate aminotransferase,total cholesterol,amino acid,glycerin three greases etc.),and sensitive antibiotic treatment were compared respectively.To investigate the prognostic factors of MRSA pneumonia.5.All statistical tests were operated with the program SPSS17 and SPSS 17 was employed to perform test of normality.The measurement data were compared by t test(normal distribution)or Wilcoxon rank test(abnormal distribution or heterogeneity of variance).The enumeration data were compared by ?2 test.Multivariate logistic regression were used for statistics analysis that variables were significant different in univariate analysis,to calculate odds ratio(OR)and 95% confidence interval.A value of P<0.05 was considered significant.Results:1.A total of 1746 strains of Staphylococcus aureus were isolated in the past four years,among which there were 117 strains of MRSA.The isolation rate of MRSA tended to decrease year by year(2013:70.5%,2014:65.1%,2015:61.3%,2016.1-9:58.2%).Clinical specimens of 72 cases of MRSA pneumonia were mostly found in sputum specimens,followed by blood samples.The resistance of MRSA to fluoroquinolones antibiotic rate were higher,81.9% to ciprofloxacin,93.1% to levofloxacin and 81.9% to moxifloxacin respectively,the rate to erythromycin,clindamycin were 75%,50%,to tetracycline and rifampin were 76.4% and 51.4% respectively.These strains were all sensitive to vancomycin,tigecycline,quinupristin / Dafoe Putin,and linezolid.2.Univariate analysis of 72 MRSA and MSSA pneumonia revealed that seven susceptible factors associated with infection caused by MRSA were chronic renal insufficiency(P=0.042),previous pulmonary infection within 6 months before isolation(P=0.000),central venous catheterization(P=0.000),indwelling drainage tube(P=0.000),blood purification therapy(P=0.020),previous broad-spectrum antibiotics usuage over 7 days within 1 months(P<0.001)and the pneumonia severity score(PSI score)(P<0.001).While chest imaging showed single lobe infiltration(P < 0.026)associated with MSSA pneumonia.Multivariate logistic regression analysis :Patients with chronic renal insufficiency(OR=7.713),previous broad-spectrum antibiotics usuage over 7 days within1 months(OR=3.728)and high PSI score(OR=1.013)were independent risk factors of MRSA pneumonia.3.In the 72 patients with MRSA pneumonia,29 patients died and 43 patients survived,of which we analyzed the clinical data.Univariate analysis revealed that five factors associated with poor prognosis were the chronic renal insufficiency(P=0.016),PSI score(P=0.002),PCT(P=0.017),septic shock(P=0.000),multiple organ failure(P=0.000).According to multivariate logistic regression analysis,patients with septic shock(OR=8.376,95%CI:1.236-56.762)and multiple organ failure(OR=12.419,95%CI:1.196-128.967)were independent prognostic factors in MRSA pneumonia.Conclusions:1.In the past four years,although the resistant rate of MRSA in our hospital was decreasing,the condition was serious,further monitoring and rational antibiotics usuing may have great significance in delaying the development of drug resistance.2.Patient with chronic renal insufficiency,invasive procedure,previous history of pulmonary infection,previous broad-spectrum antibiotics usuage over 7 days within 1month and high PSI score may increase MRSA pneumonia.The combination of chronic renal insufficiency and previous broad-spectrum antibiotics usuage over 7 days within 1 month and high PSI score were independent risk factors for MRSA pneumonia3.The combination of chronic renal insufficiency,PCT and high PSI score,which suggested that the poor prognosis of MRSA pneumonia.Septic shock and multiple organ failure caused by MRSA pneumonia were independent risk factors for death.4.In order to improve the prognosis,we should do several things: optimizing the application of broad-spectrum antibiotics,improving the status of patients,paying attention to the detection of pathogens and drug sensitivity before using antibiotics,initiating targeted treatment of pathogens as soon as possible.