北京地区儿童A组链球菌感染临床分离株的emm分型研究

目的了解2015年北京地区分离自呼吸道感染患儿的A组链球菌(GAS)emm型别分布情况。方法采集2015年5月至7月北京市16个区16家医院儿科门、急诊临床猩红热病例和咽部感染病例咽拭子标本分离的GAS菌株。应用PCR扩增联合基因测序技术,测定emm型别,并比较不同特征组间的emm基因型别差异。结果从各区医院采集的咽拭子标本中分离247株GAS菌株。其中来自猩红热患儿73株(29.6%,73/247),咽部感染患儿174株(70.4%,174/247)。共检测到6种emm基因型,emm12占53.4%(132/247),emm1占44.1%(109/247),其他型别(emm22、emm75、emm131、emm241)占2.5%(6/247)。emm型别的分布在不同年龄组间存在差异,且差异有统计学意义(P0.05),emm1在6~12岁年龄组中的构成比较高,emm12在1~5岁组中构成比较高。emm型别在地区、性别、疾病类型间差异无统计学意义(P0.05)。结论 2015年北京地区儿童A组链球菌的emm基因型中,主要的流行型别为emm12和emm1,其分布不同年龄组间存在差异。     

深圳西部地区儿童A族链球菌感染的emn基因型与T型关系与作用

选择深圳西部地区常见疾病感染GAS的儿童为研究对象。采用聚合酶链式反应扩增GAS的M蛋白的N末端,对产物进行测序分析。结果 200份标本中,共分离出GAS 92株,阳性率为46.00%(92/200)。主要流行菌株基因型emm1和emm12,在性别、年龄、临床诊断中的差异无统计学意义(P0.05)。emm基因型方法快速、准确,深圳西部地区GAS菌株emm基因型主导型的emm1和emm12等,且和T分型的对应关系良好,在不同人群及疾病中的分布差异不明显。     

深圳地区儿童A群致病性链球菌感染流行现状及M蛋白基因分型分析

目的 了解深圳地区儿童A群致病性链球菌(group A streptococcus,GAS)感染流行现状及其M蛋白基因(emm)分布状况,为该区GAS疫苗的研制提供科学依据。方法 收集2014年3月～2015年12月来医院门诊和住院部就诊的急性咽炎、急性化脓性扁桃体炎、风湿热及猩红热患儿的咽拭子及皮肤化脓性感染伤口分泌物共1 634例,分别对标本进行细胞培养与鉴定,分析不同年龄儿童GAS感染流行情况,并对GAS的M蛋白N末端进行PCR扩增测序,分析GAS的emm基因分型及其在疾病中的分布情况。结果 1 634例标本中共分离鉴定出61株GAS,检出率为3.73%(61/1 634),其中学龄前和学龄儿童分别检测出14株和47株,检出率分别为22.95%(14/61)和77.05%(47/61),学龄儿童GAS感染率明显高于学龄前儿童,两者结果之间差异有统计学意义(χ2=32.035,P<0.01),但学龄儿童不同年龄段GAS感染率之间比较差异无统计学意义(χ2=1.572,P>0.05); GAS在急性咽炎和化脓性扁桃体炎的患儿中检出率最高,分别为34.43%(21/61)和27.87%(17/61); 61株GAS的emm基因型以emml和emm12最为多见,分别占40.98%(25/61)和29.51%(18/61)。结论 深圳地区学龄儿童GAS感染率明显高于学龄前儿童,且以急性咽炎和急性化脓性扁桃体炎患儿检出率最高。61株GAS感染的emm基因以emm1和emm12为主,因此,各地加强GAS的emm基因分型研究,可为该区GAS疫苗的研制提供重要的分子流行病学依据。     

2011年北京市朝阳区儿童A组溶血性链球菌的emm基因分型及耐药性分析

目的 了解2011年北京市朝阳区儿童感染A组溶血性链球菌(GAS)的emm基因分型及对红霉素和克林霉素的耐药情况及耐药基因谱的特点。 方法 从猩红热或咽峡炎及扁桃体炎儿童患者的咽拭子培养分离获得71株GAS,应用PCR扩增emm基因及红霉素耐药基因mefA、ermA、ermB和转座子基因Tn916;采用E-test法进行药敏试验并分析耐药情况。 结果 北京市朝阳区儿童感染GAS的emm12.0基因型占87.4%,其次为emm1.0型(9.8%)、emm22.0型(1.4%)、emm75.0型(1.4%);GAS对红霉素和克林霉素的耐药率为100%和95.8%,两种药物的交叉耐药率为95.8%;耐药基因ermA、ermB、mefA和转座子基因Tn916的携带率分别为5.6%、90.1%、4.2%和90.1%。 结论 北京市朝阳区2011年儿童感染GAS的主要流行株为emm12.0型,对红霉素普遍具有较高的耐药率且与克林霉素之间存在显著的交叉耐药;ermB基因是决定本地区2011年儿童感染GAS对红霉素耐药的重要基因;而Tn916转座子基因在GAS菌株间耐药基因扩散中起重要作用。     

2005-2017年广东省猩红热流行特征分析

目的分析2005 — 2017年广东省猩红热的流行特征,为防控猩红热提供科学依据。方法应用描述性流行病学方法分析国家疾病监测信息报告管理系统中2005 — 2017年广东省猩红热病例时间、地区和人群分布特征;应用Joinpoint软件估计发病率平均年度变化百分比（AAPC）,分析猩红热发病趋势;对2017年分离的66株A族β溶血性链球菌（GAS）进行emm基因分型和抗生素敏感性分析。结果2005 — 2017年广东省共报告猩红热病例20 157例,年均发病率为1.46/10万,无死亡病例。 发病呈夏、冬两季高发特点;报告发病率高的地区为珠江三角洲地区,病例数占全省的95.79%;病例主要集中在3 ~ 7岁,以托幼儿童、散居儿童和学生为主。 广东省猩红热发病水平总体呈上升趋势,AAPC为26.4%（95%CI:16.9% ~ 36.7%）。 GAS菌株emm基因型别以emm12型为主（65.12%）,emm1型次之（32.56%）;菌株对红霉素、克林霉素、四环素耐药;对青霉素、头孢噻肟和左旋氧氟沙星均敏感。结论2005 — 2017年广东省猩红热发病水平总体呈上升趋势,三间分布特征未见明显变化;当前GAS菌株流行基因型为emm12和emm1,且菌株对青霉素敏感。     

2012-2018年山东省济南市A族β溶血性链球菌分子分型特征研究

目的了解济南市A族β溶血性链球菌（GAS)的emm分型特点，为猩红热病原学监测提供数据。方法收集2012 — 2018年济南市GAS菌株，应用PCR方法扩增emm基因，扩增产物经测序、比对，获得菌株emm基因型。结果共获得GAS菌株143株，检测到5个emm基因型，其中emm12占55.2%（79/143），emm1占42.0%（60/143），其他emm基因型占2.8%（4/143）。 2015年和2016年仅分到11株菌，均为emm12。 患者分离菌株116株，分为4种emm基因型，emm1（46株）和emm12（67株）共占97.4%（113/116），emm22（1株）和emm75（2株）共占2.6%（3/116）。 143株GAS菌株中，菌株数量排在前3位的分别为市中区（85株）、槐荫区（35株）和历城区（9株）。结论2012 — 2018年济南市GAS菌株优势基因型为emm12和emm1。 2013年和2014年以emm1为主，其余年份以emm12为主。     

上海成人和儿童患者分离的A群链球菌分子流行病学分析

目的研究和比较上海成人和儿童患者分离的A群链球菌(GAS)耐药、克隆分型、emm分型、生物膜形成及毒力因子携带等分子特征,为感染控制及治疗提供临床流行病学信息。方法 39株成人(13株)和儿童(26株)患者分离的GAS,用K-B纸片法测定对9种常用抗菌药物的敏感性;采用多位点序列分型(MLST)方法进行克隆分型;采用编码M蛋白的emm基因序列分析进行基因分型;采用脉冲场凝胶电泳(PFGE)方法分析不同emm型菌株的基因组特征;采用半定量生物膜形成试验分析其生物膜形成。聚合酶链反应(PCR)方法检测20个包括超抗原在内的GAS主要毒力基因。结果 39株GAS主要基因型为emm12-ST36(64.1%),emm1-ST28(17.9%);成人和儿童均以emm12-ST36为主。儿童菌株对红霉素和克林霉素的耐药率显著高于成人(P=0.008 7)。相同emm分型-克隆分型菌株在PFGE脉冲场带型中呈现高度聚集。生物膜形成与emm1型菌株明显相关(P=0.005),与红霉素和克林霉素耐药密切相关(P=0.000 3),儿童菌株的生物膜形成强于成人菌株(P0.000 1)。毒力基因speG、speB、sdaB、Mac全部阳性;speA、speJ、spd3与emm1型菌株有明显相关(分别为P0.000 1、P=0.005 5、P0.000 1);speI、sic与emm12型菌株有明显相关(均为P0.000 1);speH、ssa在emm12和emm1型菌株中有明显分布差异(分别为P=0.036 4、P=0.025 8);20个毒力基因在成人和儿童emm12型菌株中均没有明显分布差异(均为P0.05)。结论 emm分型与克隆分型、PFGE、毒力基因有很好相关性。成人和儿童菌株在耐药情况、生物膜形成中均存在差异。特定emm型菌株与抗生素耐药和致病力密切相关,为感染控制提供依据。重要毒力基因将是未来研制新型疫苗降低GAS感染的新型靶标。     

上海市嘉定地区感染患儿分离的化脓链球菌分子流行病学分析

目的了解上海市嘉定地区感染患儿分离的化脓链球菌emm分型及其耐药特点,为临床治疗和感染控制提供相关信息。方法收集2014年11月至2015年7月在上海交通大学医学院附属瑞金医院北院门诊就诊的急性上呼吸道感染、急性扁桃体炎、急性咽炎等患儿或带菌者咽拭子样本分离的化脓链球菌75株。应用API 20 Strep链球菌鉴定板条进行菌株鉴定,并用纸片扩散法检测菌株对8种常用抗菌药物的敏感性。应用聚合酶链反应(PCR)扩增编码M蛋白的emm基因,对PCR扩增后的emm基因产物进行测序,通过比对,获得菌株的emm分型结果。采用脉冲场凝胶电泳(PFGE)分析不同emm基因型菌株的特征,并将75株化脓链球菌结果导入Bio Numerics软件进行聚类分析。结果上海市嘉定地区化脓链球菌对红霉素、克林霉素的耐药率分别为94.7%和97.3%,对红霉素和克林霉素的双重耐药率为93.3%。具有相同emm基因型的菌株在PFGE带型上高度聚集,其中存在占优势的PFGE型。在临床分离的75株化脓链球菌中,emm1基因型菌株25株(33.3%,25/75),emm12基因型菌株49株(65.3%,49/75),emm22基因型菌株仅1株(1.3%,1/75)。结论目前上海市嘉定地区儿童咽拭子样本分离得到的化脓链球菌对红霉素普遍耐药,且与克林霉素存在较严重的交叉耐药现象。emm12或emm1基因型菌株是上海市嘉定地区儿童主要感染的化脓链球菌类型。     

纤维结合蛋白基因在儿科A族β溶血性链球菌的分布及与大环内酯类抗生素耐药的关系

目的研究纤维结合蛋白基因在我国儿科A族β溶血性链球菌(GAS)中的分布及与大环内酯类耐药之间的关系。方法收集3所儿童医院191株病原菌株,48株健康携带株,采用琼脂稀释法测定5种大环内酯类抗生素的MIC值,确定其药物敏感性;PCR扩增及测序对菌株进行emm分型;PCR检测纤维结合蛋白基因prtF1、prtF2和大环内酯类抗生素耐药基因ermB、ermTR和mefA。结果分离株的ermB阳性的有186株,ermTR阳性的有11株,prtF1、prtF2及两者同为阳性的菌株携带率分别为67.36%、66.11%和59.00%,prtF1在病原菌株和健康携带株中没有差别,prtF2在健康分离株携带率高于病原菌株,prtF1、prtF2两者集中在emm12,emm22型菌株中阳性率高,而在emm1、emm4型中很少存在。prtF1和prtF2同时阳性在ermB阳性大环内酯类抗生素耐药菌株中更为常见。结论在我国儿科GAS分离株中,以共同携带prtF1/prtF2基因的emm12型菌株为主,多存在于健康儿童中,这可能是造成我国的GAS感染耐药水平高,而侵袭性不高的原因之一。     

安宁市人乳头瘤病毒检测及感染人群特征分析

目的了解不同亚型人乳头瘤病毒(HPV)在云南省安宁市的感染状况及感染人群特征,为该市HPV感染的筛查及相关疾病的防治提供理论依据。方法应用PCR-反向点杂交技术对1 200份宫颈脱落细胞标本中的15种高危型和6种低危型HPV-DNA进行检测。结果 1 200份检测标本中,HPV总感染率为23.50%。21种基因型中检出18种HPV亚型,高危HPV占89.00%,高危HPV优势亚型依次为HPV16(19.15%)、HPV52(14.89%)、HPV58(13.48%)亚型;低危亚型主要以CP8304为主(6.38%);HPV42、44、59基因型未被检出。阳性标本中以单一型别的感染为主(76.60%)。HPV感染的高危人群年龄为30~50岁。结论安宁市女性HPV感染以单一型别感染为主,其中高危型HPV16、52、58亚型为主要感染型别;HPV感染与年龄有一定关系,30~50岁女性为该病毒的易感人群。     

Epidemiology and antibiotic resistance of group A streptococci isolated from healthy schoolchildren in Korea

OBJECTIVES: To assess the epidemiology, antibiotic resistance and genotypic characterization of group A streptococci (GAS) in Jinju, Korea. METHODS: Isolates were characterized in terms of their antibiotic resistance, the phenotypes of erythromycin resistance, the frequencies of erm(B), erm(A) and mef(A) genes, and by emm genotyping or M typing. The data were compared with those from 85 GAS strains collected during 1995 in the same area. RESULTS: A total of 98 (16.9%) of 581 healthy schoolchildren yielded GAS from throat swab culture during 2002. The most frequent emm types were emm12 (34.4%), followed by emm75 (10.4%), emm18 (9.4%), emm22 (8.3%) and emm1 (7.3%) in 2002, whereas M12 (21.2%) and M22 (14.1%) were common in 1995. The resistance rates to erythromycin and clindamycin in 2002 were 51.0% and 33.7%, respectively, compared with 29.4% and 10.1% in 1995. Among the erythromycin-resistant strains, constitutive resistance, inducible resistance, and the M phenotype were observed in 61.2%, 2.0% and 36.7% in 2002, compared with 64.0%, 0% and 36.0% in 1995, respectively, which correlated with the presence of resistance genes. Most of the emm12 strains showed constitutive resistance, whereas emm18 and emm75 showed the M phenotype. The organisms with other emm genotypes were susceptible to both erythromycin and clindamycin. CONCLUSIONS: Erythromycin and clindamycin resistance increased markedly during the period 1995-2002 in Korea. Constitutive resistance is more common than the M phenotype, with inducible resistance occurring rarely. The phenotypes of erythromycin resistance seem to be associated with certain emm genotypes.     

Molecular epidemiology of group A streptococcus causing scarlet fever in northern Taiwan, 2001-2002

In this study, 830 Streptococcus pyogenes isolates collected between 2001 and 2002 from patients with scarlet fever in northern Taiwan were analyzed by M protein gene (emm) sequence typing, pulsed-field gel electrophoresis (PFGE), and antimicrobial susceptibility testing. A total of 21 emm types and 56 PFGE patterns were identified. The most frequent emm types were emm1 (29.2%), emm4 (24.1%), emm12 (19.0%), emm6 (15.8%), stIL103 (5.7%), and emm22 (1.9%). Antimicrobial resistance profiles were determined, and resistance to erythromycin (24.6%), clindamycin (2.0%), and chloramphenicol (1.3%) was detected. Five major emm types (emm4, emm12, emm1, emm22, and emm6) accounted for 95.6% of the erythromycin-resistant isolates. The decreased prevalence of erythromycin-resistant emm12 strains coincided with the overall decrease in erythromycin resistance from 32.1% in 2001 to 21.1% in 2002 in Taiwan. Five major clones (emm4/2000, emm12/0000, emm4/2010, emm1/1000, and emm22/8100) represented 72.1% of the erythromycin-resistant isolates. The survey of group A Streptococcus emm types, genetic diversity, and antibiotic resistance has direct relevance to current antimicrobial use policies and potential vaccine development strategies.     

The severity of Streptococcus pyogenes infections in children is significantly associated with plasma levels of inflammatory cytokines

Cytokines are intimately involved with the innate and adaptive immune response to bacterial infections. This study was designed to determine the expression of inflammatory cytokines in children by the severity of Streptococcus pyogenes (group A Streptococcus [GAS]) infections. The study population consisted of 16 invasive, 20 noninvasive, and 24 pharyngeal colonization, and 21 healthy controls. All children underwent the laboratory tests and cytokine measurement. GAS isolates were analyzed for emm gene typing. Patients with invasive GAS diseases had significantly higher interferon (IFN)-γ, interleukin (IL)-1β, IL-6, IL-8, IL-10, and IL-18 than those with noninvasive diseases, colonization, and healthy controls. There was no difference in tumor necrosis factor (TNF)-α, IL-12, and IL-2 levels among the groups. Elevated white blood cell counts and levels of C-reactive protein and C3 were detected only in patients with invasive diseases. emm1 and emm12 predominated in invasive disease and colonization. Children with invasive GAS infections exhibited significant up-regulation of plasma levels of IFN-γ, IL-1β, IL-6, IL-8, IL-10, and IL-18, and suppression of TNF-α and IL-12 during the acute phase of their illness. An exuberant cytokine response was associated with the severity of illness.     

Prevalence of emm types and antibiotic resistance of group A streptococci in Austria

The prevalence of emm types and the antibiotic resistance patterns of consecutive isolates of Streptococcus pyogenes from South-East Australian patients collected in 1996 and 2003 were determined. Emm 1, emm 4, emm 12, and emm 28 were found to be the predominant types. A remarkable decrease of macrolide resistance from 1996 (19%) to 2003 (3%) was observed.     

Reemergence of macrolide resistance in pharyngeal isolates of group a streptococci in southwestern Pennsylvania

We previously reported on the emergence of macrolide-resistant pharyngeal isolates of group A streptococci (GAS) in our community. The purpose of the present study was to track longitudinal trends in macrolide resistance in these isolates in southwestern Pennsylvania. Testing for susceptibility to erythromycin and clindamycin was performed for all pharyngeal GAS isolates recovered at the Children's Hospital of Pittsburgh and a local pediatric practice between September 2001 and May 2002. Macrolide resistance phenotypes and genotypes were determined by double-disk diffusion and PCR, respectively. Strain relatedness was determined by field inversion gel electrophoresis and emm gene sequence typing. A total of 708 isolates of GAS were recovered during the study period; 68 (9.6%) were macrolide resistant, while all isolates were sensitive to clindamycin. The monthly prevalence of macrolide resistance ranged from 0 to 41%. Only 21 of 573 (3.7%) strains recovered from September 2001 through March 2002 were macrolide resistant. A sudden increase in the rate of macrolide resistance (47 of 135 isolates [35%]) was seen in April and May 2002. Sixty-two isolates demonstrated the M phenotype (resistance to macrolide antibiotics), and six isolates demonstrated the MLS(B) phenotype (resistance to most macrolide, lincosamide, and streptogramin B antibiotics); these isolates were confirmed to be mef(A) and erm(A), respectively. Three unique mef(A) clones and four unique erm(A) clones were identified among the resistant isolates. The MIC at which 50% of isolates are inhibited (MIC(50)) for the mef(A) strains was 16 micro g/ml, while the MIC(50) for erm(A) strains was 8 micro g/ml. The finding of high levels of macrolide resistance among pharyngeal isolates of GAS for a second successive year in our community raises the concern that this problem may be more common in the United States than was previously appreciated. Longitudinal surveillance of isolates from multiple centers is needed to define the prevalence of antimicrobial agent-resistant GAS in the United States.     

Erythromycin-resistant pharyngeal isolates of Streptococcus pyogenes recovered in Italy

Three classes of macrolide resistance phenotypes and three different erythromycin resistance determinants were found among 127 erythromycin-resistant group A streptococcal (GAS) isolates recovered from 355 (35.8%) pediatric pharyngitis patients in Rome, Italy. According to emm and sof sequence typing results, erythromycin-resistant isolates comprised 11 different clonal types. Remarkably, 126 of the 127 macrolide-resistant isolates were serum opacity factor (sof) gene positive. These data suggest a strong association between macrolide resistance and the presence of sof among GAS isolates recovered from Italian pediatric pharyngitis patients.