医院内MRSA感染危险因素分析及毒力、耐药基因检测

发布时间：2018-06-29 08:13

  本文选题：耐甲氧西林金黄色葡萄球菌 + 危险因素　； 参考：《苏州大学》2016年博士论文

【摘要】：第一部分医院内MRSA感染危险因素研究目的探讨医院内耐甲氧西林金黄色葡萄球菌(MRSA)感染的危险因素,为提出有效减少医院MRSA感染的措施提供依据。方法对宁波市某三级甲等综合性医院2013年、2014年的MRSA、MSSA感染进行监测。以监测收集到的所有院内MRSA患者为病例组,以院内MSSA患者为对照组进行危险因素研究。查阅病案收集病例和对照既往暴露资料,考虑的暴露因素包括年龄、基础疾病(心脑血管疾病、糖尿病、肿瘤、结构性肺病、肝肾功能不全)、住院时间、侵入性操作(种类、个数)、使用抗生素(暴露时间、暴露个数)等。运用卡方检验、非条件logistic回归模型进行危险因素分析。结果1、样本量:本研究共入组MRSA组的患者118例,MSSA组116例。2、菌株分布特点:MRSA菌株以神经内科、脑外科分离株最多,两科共占32.21%;MSSA菌株以骨科分离到最多,占25.86%。标本类型中,MRSA主要为痰液分离株,而MSSA主要为创面分泌物分离株。3、本研究显示,MRSA组的住院时间显著长于MSSA组。4、危险因素分析:单因素分析发现年龄、中枢神经系统疾病、基础疾病数量、侵入性操作(动静脉置管、气管插管、留置胃管、留置导尿管、术后引流)的暴露及侵入性操作数量、细菌分离前住院时间、抗生素暴露时间、抗生素暴露个数在MRSA组和MSSA组间存在差异(P0.05)。多因素分析发现仅侵入性操作个数、抗感染药物暴露≥2种、抗感染药物暴露时间≥7天这3个因素是MRSA感染的危险因素(P0.05)。结论侵入性操作个数、抗感染药物暴露≥2种、抗感染药物暴露时间≥7天是MRSA相对于MSSA的独立危险因素,因此避免非必要性的侵入性操作、合理应用抗感染药物是预防MRSA的重要手段。第二部分金黄色葡萄球菌血液分离株毒力与耐药编码基因研究目的分析院内MRSA及MSSA血液分离菌株临床及菌株分子生物学特征,了解MRSA的毒力和耐药机制。方法对某三级甲等医院2011年1月~2012年12月自血液分离的19株MRSA和13株MSSA的临床特征进行分析,采用琼脂稀释法对32株金葡菌进行抗菌药物敏感性检测;采用聚合酶链式反应(PCR)在32株菌株中检测55种毒力基因(黏附毒素sas X、fnb A、clf A、clf B、ica A、cna、efb、isd A、isd B、isd C;细胞毒素hla、hlb、hld、hlg、hlg-2、pvl、luk E、luk M、psm-mec;侵袭性酶ssp、sak、nuc、hys A、lip;超抗原sea、seb、sec、sed、see、seg、seh、sei、sej、sek、sel、sem、sen、seo、sep、seq、eta、tst;外毒素set1、set2、set3、set4、set5、set6、set7、set8、set9、set10、set11;荚膜抗原cap5、cap8)和7种耐药基因(mec A、aac(6’)/aph(2”)、aph(3’)-Ⅲ、erm A、erm B、erm C、tet M)。随机选取上述PCR阳性产物进行测序,测序结果用Chromas软件直接做BLAST Search比对;金黄色葡萄球菌毒力与耐药基因检测结果作样本聚类分析(UPGMA法)。结果1、临床特征:感染MRSA的患者平均年龄为(78.5±7.6)岁,高于MSSA患者(67.6±15.3)岁(P0.05)。两组细菌检出时间分别为入院后(9.84±4.11)天和(6.93±3.26)天(P0.05),MRSA组检出时间晚于MSSA组。2、药敏试验:32株金葡菌均对万古霉素敏感。MRSA的耐药率由高到低为:苯唑西林(100.0%)、青霉素(100.0%)、氨苄西林(100.0%)、头孢唑林(100.0%)环丙沙星(94.7%)红霉素(84.2%)克林霉素(73.7%)四环素(52.6%)、庆大霉素(52.6%)利福平(26.3%)磺胺甲VA唑/甲氧苄啶(21.1%)万古霉素(0.0%)。3、毒力基因检出情况:本组金黄色葡萄球菌中黏附毒素、细胞毒素、侵袭性酶、超抗原、外毒素、荚膜抗原六大类毒力基因均有检出,其中毒力基因cna、luk E、psm-mec、ssp、nuc、lip、seg、sem、sen、set6、set11在MRSA组和MSSA组的检出率存在差异(P0.05)。55种毒力基因中有12种未检出,分别为hlg、luk M、sak、eta、seb、sec、sed、sej、sel、set2、set4、set5。MRSA组的菌株携带的毒力基因个数多于MSSA组的菌株(P0.05)。4、耐药基因检出情况:mec A、aac(6’)/aph(2”)、aph(3’)-Ⅲ、tet M这4个耐药基因的表达在MRSA组与MSSA组间存在统计学差异(P0.05)。erm A、erm B在两组中均未检出。5、样本聚类分析中可见两组菌株中均存在克隆现象,提示院内感染。结论MRSA菌与MSSA菌黏附素基因检出率高提示菌株的定植特性。MRSA组毒力基因的检出个数高于MSSA组,提示MRSA具有更强的宿主组织损伤特性。在临床处置中要特别注意院内感染的控制手段以降低感染风险。
[Abstract]:The first part of the hospital MRSA infection risk factors study to explore the risk factors of methicillin resistant Staphylococcus aureus (MRSA) infection in hospital, in order to provide effective measures to reduce the hospital MRSA infection measures to provide the basis. Methods for a three grade a comprehensive hospital in Ningbo in 2013, 2014, MRSA, MSSA infection monitoring. All the hospitalized MRSA patients were the case group and the MSSA patients in the hospital were used as the control group for the risk factors. The exposure factors including age, basic disease (cardio cerebrovascular disease, diabetes, tumor, structural lung disease, liver and kidney insufficiency), hospitalization time, invasive operation were considered. (type, number), use of antibiotics (exposure time, exposure number) and so on. Using chi square test and unconditional logistic regression model, the risk factors were analyzed. Results 1, sample size: 118 cases in group MRSA, 116 cases in group MSSA, 116 cases of.2, the distribution characteristics of strain: MRSA in the neurology, the Department of cerebral surgery, the most, the two families accounted for 32.21%; MSSA isolates were most isolated in the Department of orthopedics, accounting for the type of 25.86%. specimens, MRSA was mainly sputum isolation, and MSSA was mainly the.3 of the wound secretions. This study showed that the time of hospitalization in the MRSA group was significantly longer than that of the MSSA group.4, and the risk factors were analyzed: the single factor analysis found the age, central nervous system disease, the number of basic diseases, invasive operations. (IV) (arteriovenous catheterization, tracheal intubation, indwelling gastric tube, indwelling catheter, postoperative drainage) exposure and invasive operation number, the time of hospitalization before bacterial isolation, antibiotic exposure time, and the number of antibiotic exposure between the MRSA group and the MSSA group (P0.05). The 3 factors of the exposure time of the infected drugs over 7 days are the risk factors of MRSA infection (P0.05). Conclusion the number of invasive operations, the exposure of anti infective drugs more than 2, and the exposure time of anti infective drugs over 7 days are independent risk factors of MRSA relative to MSSA, so the non essential invasive operation is avoided, and the rational application of anti infective drugs is the prevention of MRSA. Important means. The second part of the toxicity and resistance encoding gene of Staphylococcus aureus blood isolates were used to analyze the clinical and molecular biological characteristics of MRSA and MSSA isolated strains in hospital and to understand the virulence and resistance mechanism of MRSA. Methods 19 strains of MRSA and 13 isolated from the blood of a Class Three Grade A hospital in December January 2011 were isolated from blood. 32 strains of Staphylococcus aureus were detected by agar dilution method, and 55 kinds of virulence genes were detected by polymerase chain reaction (PCR) in 32 strains (SAS X, FNB A, CLF A, CLF B, ICA A). Sm-mec, invasive enzyme SSP, sak, NUC, HYS A, lip; superantigen sea, SEB, SEC, sed. The PCR positive products were sequenced by the machine, and the sequencing results were directly compared with the BLAST Search comparison with the Chromas software. The results of the toxicity and resistance genes of Staphylococcus aureus were analyzed by cluster analysis (UPGMA method). Results 1, the clinical characteristics: the average age of the patients infected with MRSA was (78.5 + 7.6) years old, higher than that of the MSSA patients (67.6 + 15.3) years (P0.05) two. The time of detection of bacteria was (9.84 + 4.11) days and (6.93 + 3.26) days (P0.05). The detection time of group MRSA was later than.2 in group MSSA, and drug sensitivity test: the resistance rate of 32 strains of Staphylococcus aureus to vancomycin sensitive.MRSA was from high to low: benzoxacillin (100%), penicillin (100%), ampicillin (100%), and cefazolin (100%) ciprofloxacin (94.7%) Erythromycin (84.2%) clindamycin (73.7%) tetracycline (52.6%), gentamicin (52.6%) rifampin (26.3%) sulfamethoxazole / trimethoprim (21.1%) vancomycin (0%).3, virulence gene detection: this group of Staphylococcus aureus in this group of adhesion toxin, cytotoxin, invasive enzyme, superantigen, exotoxin, capsule antigen six major toxic genes have been examined. The virulence genes of cna, Luk E, psm-mec, SSP, NUC, lip, SEG, SEM, Sen, set6 were different. 4, the detection of resistance genes: MEC A, AAC (6 ') /aph (2 "), APH (3') - III, Tet M, the expression of 4 resistance genes between the MRSA group and the MSSA group was statistically different (P0.05).Erm A. The high detection rate of the attachment gene suggests that the number of virulence genes in the.MRSA group is higher than that of the MSSA group, suggesting that MRSA has a stronger host tissue damage characteristic. In clinical treatment, special attention should be paid to the control of nosocomial infection to reduce the risk of infection.
【学位授予单位】：苏州大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：R446.5
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