| Objective: To investigate the cases of methicillin-resistant Staphylococcus aureus(MRSA) infections, study the current situation that infection caused by MRSA in the intensive care unit and explore the risk factors, clinical characteristics and prognosis for the MRSA infections in an Intensive Care Unit so as to provide scientific data for measures to prevent and control MRSA infections. Methods: The research was done to detect MRSA in 787 cases of inpatients in ICU from January 2012 to December 2013. From Jan 1,2012 to Dec 31,2013, the patients with MRSA infections were selected as the case group, the patients without MRSA infections were set as the control group;by means of epidemiological survey,the variables and risk factors were mainly determined according to the review and working experience, the statistical analysis was performed with the use of SPSS 17.0 software. Non-conditional logistic regression analysis model was used for single factor and multi-factor analysis to look for independent risk factors of MRSA infections in ICU. Two independent sample t-test was used to compare two groups’ laboratory indexes( including routine blood, liver function, renal function, coagulation function, blood gas analysis,etc). The mortality and incidence of liver dysfunction between two groups were compared with Chi-square test. Results:1. The results showed that in 86 cases infected with SA(Staphylococcus aureus) there were 54 patients with MRSA infection. MRSA infection rate was detected in 62.79% from Staphylococcus aureus. Among them, the infection rate in 2012 was 68.18% and 57.14% in 2013. In 787 cases of inpatients, the total incidence rate of MRSA infection was 6.86%. Among them,the incidence rate in 2012 was 8.13% and the incidence rate in 2013 was 5.74%( χ2 =1.749, P =0.186).2. Totally 62 variables were included in the univariate analysis, and 12 were screened out through the statistical analysis and brought into the multivariate logistic regression model.Age( OR = 1.047,95%CI:1.009~1.086), length of ICU stay( OR= 1.050,95%CI:1.012~1.089), steroid administration( OR = 2.853,95%CI:1.177~6.911), mechanical ventilation(MV)(OR = 4.918,95%CI:1.175~20.583) and duration of drug therapy more than 7 days(OR = 3.257,95%CI:1.055~10.058) were the independent risk factors for MRSA infection.The exposure rate of mechanical ventilation was 92.59% in the patients with MRSA infection, 59.21% in the patients without MRSA infection( χ2 =23.673,P <0.001),The exposure rate of using steroid was 62.96% in the patients with MRSA infection, 25.24% in the patients without MRSA infection( χ2 =35.64,P<0.001), The exposure rate of antibiotics more than 7 days was 74.07% in MRSA infectrion group, the exposure rate of antibiotics less than 7 days was 20.87% in non-MRSA group( χ2 =76.90,P<0.001). The exposure rate of using broad-spectrum antibiotics was 81.48 % in the case group, 66.44 % in the control group(χ2 = 5.185,P = 0.023).3. To collect two years of non-repeating MRSA strains of the Second Hospital of Tianjin Medical University, of all the MRSA stains found in the samples, 30(55.56%) stains were in sputum,14(25.93%) in bronchoalveolar lavage fluid, 8(14.81%) in throat swab and 2( 3.70%) in blood.4. T test revealed that the average blood platelet counts in MRSA infection group was(220.74 ± 88.81)*109/L, but the average blood platelet counts in non-MRSA infection group was(183.92 ± 102.04)*109/L. There were significant differences on blood platelet counts(t = 2.492,P = 0.013). It was(24.43± 8.07) mmol/L that the MRSA infection group was in actual bicarbonate radical, higher than control group(21.85±7.56) mmol/L( t =2.282,P = 0.023).5. Two independent sample T-test revealed, MRSA infection group was( 24.94±33.19) d in average ICU days, but non-MRSA infection group was(7.69±9.19) d. There were significant differences on days in ICU( t = 7.685,P <0.001). ALB<28g/L had 30 cases in MRSA infection group, accounting for 55.56%, 299 cases in non-MRSA infection group, accounting for 40.79%( χ2 = 4.506, P =0.034).The incidence of RR>20bpm in MRSA group was 62.96%, 48.84% in non-MRSA group( χ2= 4.013,P =0.045). Conclusion: Old age, long-term ICU stay, steroid administration, mechanical ventilation and long-term use of antimicrobial agents are the independent risk factors for the bacterial infection. MRSA infection lead to higher blood platelet counts and higher actual bicarbonate radical. MRSA infection also prolongs the length of stay of inpatients in ICU. The incidence of liver and lung dysfunction in MRSA patients is higher. It is necessary to take effective prevention and control measures according to the patients′ condition so as to prevent the emergence and spread of drug resistant strains. |
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