A族乙型溶血性链球菌耐药性和分子流行病学调查研究

发布时间：2018-05-18 07:20

本文选题：A族乙型溶血性链球菌 + 耐药性　；参考：《重庆医科大学》2009年硕士论文

【摘要】： 研究背景A族乙型溶血性链球菌(group A streptococcus pyogens,GAS)是链球菌中致病性较强的一种细菌,是急性呼吸道感染尤其是上呼吸道感染的重要致病原,可以引起急性扁桃体炎、猩红热和脓疱疮,也可引起严重的侵袭性感染如败血症、坏死性筋膜炎和链球菌中毒休克综合征。然而,随着大环内酯类抗生素的广泛使用,近十年来GAS对大环内酯类抗生素的耐药已经成为全球性关注的问题,细菌耐药性的增长已经成为临床治疗中的棘手问题。 M蛋白是GAS的主要致病因子,由emm基因编码。M蛋白抗原变异是M分型的基础,到目前为止,根据M蛋白抗原特异性可将GAS分为100多个型别,不同的型别其致病性不同,部分菌株感染可引起人类严重并发症如风湿热/风湿性瓣膜性心脏病(RF/RHD)及急性肾小球肾炎等,因此,GAS分型对流行病学研究有重要意义。然而,GAS对大环内酯类抗生素的耐药性及分子流行病学的大规模研究在国内报道甚少,而重庆地区尚缺乏儿童GAS分离株耐药性和分子流行病学大规模调查研究。目的了解重庆地区GAS耐药特点;了解重庆地区GAS的emm基因分布特点;分析重庆地区emm基因的主导型和感染性GAS的emm基因与疾病的关系。方法收集我院住院患儿正常无菌部位血液、脓液、胸水标本及我院门诊患儿咽部、皮损部标本及健康儿童咽部咽拭子标本进行培养、分离、鉴定A族乙型溶血性链球菌。微量肉汤稀释法检测A族乙型溶血性链球菌对8种抗生素的敏感性。聚合酶链反应(PCR)扩增并进行测序从而对emm基因进行分型确定emm基因的型别。结果 (一)感染性GAS菌株组成 85株非侵袭性感染GAS菌株,急性扁桃体炎菌株为77株;猩红热为7株;脓疱疮的菌株为1株。5株侵袭性感染GAS菌株,2株为血培养分离株;2株为腹股沟脓肿的脓液培养分离株;1株为肺炎的胸腔积液培养分离株。 (二) GAS菌株对8种抗菌素的敏感性试验结果 1、85株非侵袭性感染GAS菌株对抗菌药的敏感性试验结果85株非侵袭性感染GAS菌株对大环内酯类抗生素和克林霉素的耐药率在91.67%-97.62%;对四环素的耐药+中介为75%;对青霉素和头孢菌素类及左氧氟沙星的敏感率均高达100%,未检测到耐青霉素、头孢菌素类抗生素GAS菌株。 2、5株侵袭性感染GAS菌株对抗菌药的敏感性试验结果5株侵袭性GAS菌株对大环内酯类抗生素如红霉素、克拉霉素以及克林霉素的耐药率均高达100%,对新一代的大环内酯类药如阿奇霉素的耐药率也高达80%;对四环素耐药+中介为80%;而对于青霉素、头孢呋辛和左氧氟沙星的敏感率仍为100%。 3、95株健康儿童携带GAS菌株对抗菌药的敏感性试验结果95株健康儿童携带GAS菌株对大环内酯类抗生素的耐药率在94.74%-96.84%;对四环素耐药+中介为86.31%;对青霉素、头孢呋辛和左氧氟沙星的敏感率均高达100%。 (三)emm基因分型结果 1、83株非侵袭性感染GAS菌株的emm基因分型结果83株非侵袭性感染GAS菌株中,最常见的型别为emm12.0,为52株,占62.65%;其次是emm1.0,为11株,占13.25%;再次是emm22.0,为8株,占9.64%;emm6.5和emm12.43均为2株,占2.41%;而emm63.0、emmSTG485.0、emmST1815.0、emm3.1、emm80.0、emm86.1、emm75.0和emm102.2均为1株,仅占1.20%。 2、5株侵袭性感染GAS菌株的emm基因分型结果5株侵袭性感染GAS菌株中3株为emm12.0;1株为emm1.0;1株无法分型。 3、84株健康儿童携带GAS菌株的emm基因分型结果84株健康儿童携带GAS菌株中,最常见的型别为emm12.0,为54株,占64.29%;其次是emm22.0,为13株,占15.48%;再次是emm6.0,为6株,占7.14%;emm1.0和emm4.0均为5株,占5.95%;而emm12.21为1株,仅占1.19%。 (四)来源于各病种的GAS与emm基因分型的对应关系结果检测扁桃体炎GAS菌株75株,以emm12.0所占比例最大为62.67%,然后依次是emm1.0(12.00%),emm22.0(10.67%)等。脓疱疮GAS菌株1株,为emm75。猩红热GAS菌株7株,其中5株为emm12.0,2株为emm1.0。败血症GAS菌株2株为emm12.0和emm1.0;腹股沟脓肿GAS菌株2株为emm12.0和无法分型;肺炎GAS菌株1株为emm12.0。结论 (1)重庆地区儿童GAS菌株对大环内酯类抗生素表现出严重的耐药,而对青霉素和头孢菌素仍然保持高度敏感,故临床推荐首选青霉素和头孢菌素类(头孢Ⅰ、Ⅱ代)抗生素治疗GAS疾病。 (2)重庆地区儿童感染性GAS菌株emm基因以emm12.0为主导型,其次为emm1.0、emm22.0等;健康儿童携带GAS菌株emm基因也以emm12.0为主导型,其次为emm22.0、emm6.0、emm1.0和emm4.0等。为此可进一步为疫苗的研究提供依据。
[Abstract]:Background A Streptococcus (group A Streptococcus pyogens, GAS) is a highly pathogenic bacterium in Streptococcus. It is an important pathogen of acute respiratory infection, especially upper respiratory tract infection. It can cause acute tonsillitis, scarlet fever and pemphigus, and can also cause severe invasive infection such as sepsis and necrosis. Sexual fasciitis and streptococcal shock syndrome. However, with the widespread use of macrolide antibiotics, the resistance of GAS to macrolide antibiotics has become a global concern over the past ten years, and the growth of bacterial resistance has become a thorny problem in clinical treatment.
M protein is the main pathogenic factor of GAS. The mutation of the.M protein antigen of the emm gene is the basis of the M typing. So far, GAS can be divided into more than 100 types according to the specificity of the M protein antigen, and the pathogenicity of different types is different. Some strains of infection can cause severe and rheumatic fever / rheumatic heart disease (RF/RHD). As well as acute glomerulonephritis, GAS typing is of great significance for epidemiological studies. However, large scale studies on the drug resistance and molecular epidemiology of macrolide antibiotics in GAS are rarely reported in China, but there is still a lack of large-scale investigation on drug resistance and molecular epidemiology of GAS isolates in children in Chongqing.
Objective to understand the characteristics of GAS resistance in Chongqing and to understand the emm gene distribution of GAS in Chongqing area, and to analyze the relationship between the dominant type of emm gene in Chongqing and the emm gene of infectious GAS and the disease.
Methods the blood of normal aseptic parts of the hospital in our hospital, the specimens of pus, chest water and the pharynx of the outpatient of our hospital, the specimen of the skin lesion and the pharynx swab of the healthy children were cultured, separated and identified, and the A group B hemolytic streptococcus was identified. The sensitivity of the 8 antibiotics was detected by the micro broth dilution method for the detection of the sensitivity of the A group of hemolytic streptococcus. Enzyme chain reaction (PCR) was amplified and sequenced, and the emm gene was typed to determine the type of emm gene.
Result
(1) the composition of infectious GAS strains
85 strains of non invasive infection GAS, 77 strains of acute tonsillitis, 7 strains of scarlet fever, 1 strains of.5 strain GAS, 2 strains of blood culture, 2 strains of abscess in the abscess of the groin, and 1 for pneumonic pleural effusion.
(two) sensitivity test of GAS strain to 8 antibiotics.
Sensitivity tests of 1,85 strains of non invasive infection GAS strains against bacteria, the resistance rate of 85 strains of non invasive GAS strains to macrolide antibiotics and clindamycin was 91.67%-97.62%, the resistance to tetracycline was 75%, and the susceptibility to penicillin and cephalosporins and levofloxacin was up to 100%, and the resistance was not detected. Penicillin, cephalosporins GAS strain.
Susceptibility test of 2,5 strain GAS strains against bacteria, 5 invasive GAS strains were resistant to macrolides, such as erythromycin, clarithromycin and clindamycin, as high as 100%, and 80% for new generation of macrolides, such as azithromycin, and 80% for tetracycline resistance + mediator; The sensitivity rate of penicillin, cefuroxime and levofloxacin was still 100%.
The sensitivity test of 3,95 strains of healthy children carrying GAS strains against bacteria drug results, the resistance rate of 95 healthy children with GAS strains to macrolide antibiotics was 94.74%-96.84%, and the resistance to tetracycline was 86.31%, and the susceptibility to penicillin, cefuroxime and levofloxacin were all up to 100%.
(three) the results of EMM genotyping
The EMM genotyping results of non invasive GAS strain of 1,83 strain 83 strains of non invasive GAS strains, the most common type was emm12.0, 52, 62.65%, followed by emm1.0, 11, 13.25%, emm22.0, 8, 9.64%, emm6.5 and emm12.43, 2.41%, and emm63.0, emmSTG485.0, emmST1815.0, emmST1815.0, 2.41% Mm86.1, emm75.0 and emm102.2 were 1, accounting for only 1.20%..
The results of EMM genotyping of GAS strain infected with 2,5 strain showed that 3 of the 5 strains of GAS infected with GAS were emm12.0, 1 were emm1.0, and 1 strains could not be classified.
The EMM genotyping of GAS strains in healthy children of 3,84 strain 84 healthy children carried GAS strains, the most common type was emm12.0, 54, 64.29%, followed by emm22.0, 13, 15.48%, emm6.0, 6, 7.14%, emm1.0 and emm4.0, 5.95%, and 1, 1, only 1.19%..
(four) the corresponding relationship between GAS and emm genotyping from each disease species detected 75 strains of GAS strain of tonsillitis, the largest proportion of emm12.0 was 62.67%, followed by emm1.0 (12%), emm22.0 (10.67%), GAS strain 1 strains of pustular sore, 7 strains of emm75. scarlet fever GAS strain, 5 of which were emm1.0. septicemia GAS strain 2 The strains were emm12.0 and emm1.0; 2 strains of GAS of the inguinal abscess were emm12.0 and incapable of classification; 1 strains of pneumonia GAS strain were emm12.0..
conclusion
(1) the GAS strain of children in Chongqing region showed severe resistance to macrolide antibiotics and remained highly sensitive to penicillin and cephalosporins. Therefore, the first choice of penicillin and cephalosporins (cephalosporin I, II) antibiotics was the first choice for the treatment of GAS disease.
(2) the emm gene of infectious GAS strain of children in Chongqing area was guided by emm12.0, followed by emm1.0, emm22.0, etc. The emm gene of GAS strain in healthy children was also guided by emm12.0, followed by emm22.0, emm6.0, emm1.0 and emm4.0, and so on, which could provide the basis for the research of vaccine.
【学位授予单位】：重庆医科大学
【学位级别】：硕士
【学位授予年份】：2009
【分类号】：R446.5;R450;R181.3

【引证文献】