杭州富阳区临床分离甲氧西林耐药金黄色葡萄球菌的流行、耐药及基因分型研究

发布时间：2018-06-06 03:18

本文选题：甲氧西林耐药金黄色葡萄球菌 + 基因分型　；参考：《浙江大学》2015年硕士论文

【摘要】：背景及意义甲氧西林耐药的金黄色葡萄球菌(methicillin-resistant Staphylococcus aureus,MRSA)是指对苯唑西林、甲氧西林、和氟氯西林等异唑青霉素耐药的金黄色葡菌球菌菌株,于1961年由Jevons首次发现,是引起医院感染的重要病原菌之一。其传播速度快,适应性强,从发现至今,感染几乎遍及全球。具有多重耐药性和潜在的致死性等特点,存在局部暴发流行的潜在威胁。我国自20世纪70年代发现第1株MRSA后,其分离率在中国迅速上升。目前MRSA已成为医院和社区人群感染的常见病原菌,不但致病能力强,耐药谱广,而且对多种抗菌药物的敏感性呈现逐年降低趋势,已经成为严重危害公众健康的感染性因子之一,使临床抗感染治疗面临极大困难,由此也成为医学界关注的焦点问题。该菌对目前临床上使用的大多数抗菌药物有很高的耐药率,并可对β内酰胺类、氨基糖苷类、喹诺酮类、大环内酯类等常用抗菌药物产生多重耐药。临床可供选择的抗生素较少,是目前抗感染治疗的难点。当前基因分型的分子流行病学研究方法在揭示病原菌的进化及遗传特性,确定某一感染暴发流行的致病菌株克隆或相关基因来源,追踪基因水平的转移与播散,调查院内耐药性质粒在不同细菌间播散等方面发挥重要作用。但截至目前国内对MRSA系统全面的基因分型及分子学特性方面的研究较少,或片面不完整。本课题采用三种基因分型技术：多位点序列分型(MLST)、葡萄球菌染色体mec基因盒(SCCmec)和葡萄球菌蛋白A基因(spa),同时应用脉冲场凝胶电泳(PFGE)对收集的菌株进行同源性分析,PCR扩增技术筛查菌株的pvl毒素基因,力求全面揭示我市MRSA流行株的具体基因型别及分子学特性。研究临床分离MRSA的流行、药物敏感性情况,有助于我们掌握本地区MRSA的流行特点及趋势,为制定控制其传播措施以及临床经验性治疗提供理论依据；开展对临床分离MRSA的基因分型研究,了解本地区或某家医院MRSA流行株的遗传和基因分型特征,分析判断流行菌株间的亲缘关系,全面揭示MRSA流行株的基因型变化趋势,药敏及流行病学特点,有助于医院或疾控部门采取有效措施控制感染的暴发流行,对于遏制流行菌株的进一步播散和积极控制MRSA的感染以及指导临床治疗、合理应用抗生素有着十分重要的意义。同时,开展对MRSA的相关研究,有利于提高基层临床医师对MRSA的知晓率,引起广大医务人员对其引起医院感染的高度重视,严格执行消毒隔离措施,积极治疗并隔离MRSA患者及携带者,严格控制广谱抗生素的应用。目的研究杭州富阳区临床分离的甲氧西林耐药金黄色葡萄球菌(MRSA)的检出率、药敏情况及基因分型、同源性分析等分子学特性,分析富阳区MRSA的流行现状。方法收集2013年11月至2014年10月两家医院从各种类型临床标本中分离出的金葡菌,对其中经筛选确认的44株MRSA进行MLST、spa、SCCmec基因分型,筛查pvl基因,应用PFGE进行菌株间的同源性分析。同时应用Vitek2 compact药敏分析系统对16种抗菌药物进行药敏实验。结果共检出MRSA44株,占金葡菌的16.4%(44/268)。两家医院流行的主要克隆不同,富阳中医骨伤医院以ST59-t437-SCCmecIV型为主,菌株间同源性程度低；人民医院以ST5-t311-SCCmecⅡ型为主,部分菌株之间同源性程度高。检出3株pvl阳性菌株,占6.8%。药敏结果示MRSA对β内酰胺类普遍耐药,红霉素、克林霉素的耐药率高,对万古霉素、利奈唑烷、替加环素保持敏感。结论富阳地区MRSA的检出率相对较低,整体呈低流行、散发态势。两家医院MRSA流行的主要克隆有较大差异。MRSA的耐药情况不容乐观,多重耐药的现象严重。不同基因型别的菌株其药敏结果有差异。
[Abstract]:Background and significance of methicillin resistant Staphylococcus aureus (methicillin-resistant Staphylococcus aureus, MRSA) is a strain resistant to oxacillin, methoxicillin, and fluroxicillin resistant Staphylococcus aureus, which was first discovered by Jevons in 1961. It is one of the important pathogens causing hospital infection. Fast and adaptable, from the discovery to the present, the infection is almost all over the world. It has the characteristics of multiple drug resistance and potential lethality, and there is a potential threat to local outbreak. Since the discovery of first MRSA strains in China in 1970s, its separation rate has risen rapidly in China. At present, MRSA has become a common cause of infection in hospitals and communities. Bacteria, which not only have strong pathogenicity, broad spectrum of drug resistance, but also reduce the sensitivity to a variety of antibiotics year by year. It has become one of the infectious factors that seriously harm public health. It has made clinical anti infection treatment face great difficulties, and it has become a focal point in medical field. Bacterial drugs have a high drug resistance rate and can produce multidrug resistance to antibiotics such as beta lactam, aminoglycosides, quinolones, macrolides and other commonly used antibiotics. The clinical selection of antibiotics is the difficult point of anti infection treatment. The current molecular epidemiology research method of genotyping is to reveal the evolution and inheritance of pathogenic bacteria. Characteristics, determine the clone or related gene source of a infectious outbreak, trace the transfer and dissemination of the gene level, and investigate the drug resistant plasmids in the hospital to play an important role in the spread of different bacteria. But at present, there are few studies on the comprehensive genotyping and genotyping of MRSA system in China. Three genotyping techniques: Multipoint sequence typing (MLST), staphylococcal chromosome mec gene box (SCCmec) and staphylococcal protein A gene (SPA) were used in this study. Meanwhile, pulse field gel electrophoresis (PFGE) was used to analyze the homology of the collected strains, and the PCR amplification technique was used to screen the PVL toxin gene of the strain. The specific genotypes and molecular characteristics of MRSA epidemic strains in our city are shown. The study of the prevalence of clinical isolation of MRSA and drug sensitivity can help us to grasp the epidemic characteristics and trends of MRSA in the region, provide theoretical basis for formulating the measures to control its transmission and clinical experiential treatment, and study the genotyping of the clinical isolates of MRSA. To understand the genetic and genotyping characteristics of MRSA epidemic strains in the local or certain hospitals, to analyze the relationship between the epidemic strains and to reveal the genotypic trend of the MRSA epidemic, the drug sensitivity and the epidemiological characteristics, which will help the hospital or the disease control department to take effective measures to control the outbreak of infection and to contain the epidemic strains. It is of great significance to further disseminate and actively control the infection of MRSA and to guide clinical treatment, and to apply antibiotics reasonably. At the same time, the study of MRSA is beneficial to the improvement of the awareness rate of MRSA by clinicians at the grass-roots level, and the attention of the medical staff to the hospital infection, and the strict implementation of the disinfection and isolation measures. To actively treat and isolate MRSA patients and carriers and strictly control the application of broad-spectrum antibiotics. Objective to study the detection rate of methicillin resistant Staphylococcus aureus (MRSA), drug sensitivity and genotyping, homology analysis of clinical isolates of methicillin resistant Staphylococcus aureus (MRSA) in Hangzhou District of Hangzhou Province, and to analyze the epidemic status of MRSA in the District of Fuyang. Methods collect 2013 methods. From November to October 2014, the two hospitals separated from various types of clinical specimens were isolated from various types of clinical specimens. 44 strains of MRSA, which were screened and confirmed, were divided into MLST, spa, SCCmec genotyping, the PVL gene was screened and PFGE was used to analyze the homology among the strains. Meanwhile, the drug sensitivity test of the 16 antibiotics was carried out by the Vitek2 compact drug sensitivity analysis system. Results a total of MRSA44 strains were detected, accounting for 16.4% (44/268) of Staphylococcus aureus. The main clones in two hospitals were different. The main hospital of Fuyang traditional Chinese medicine bone injury hospital was ST59-t437-SCCmecIV type, and the homology of the strains was low. The people's hospital was dominated by ST5-t311-SCCmec II type, and the homology was high among some strains. 3 PVL positive strains were detected, which accounted for 6.8%. drugs. The results showed that MRSA was generally resistant to beta lactam, the resistance rate of erythromycin and clindamycin was high, and vancomycin, linezolane and tigocycline were sensitive. Conclusion the detection rate of MRSA in Fuyang is relatively low, and the overall prevalence of MRSA in the two hospitals is low and the drug resistance of large difference.MRSA is not happy. Multidrug resistance is a serious phenomenon. The sensitivity of different genotypes is different.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：R446.5

【参考文献】