2014-2019年阜阳市食品和病人分离单增李斯特菌的分子特征分析

目的 比较分析阜阳市食品和病人分离单增李斯特菌的毒力基因、分子型别,建立阜阳市单增李斯特菌分子特征信息数据库,为防控单增李斯特菌病提供科学依据。方法 对阜阳市2014-2019年分离自食品和病人的55株单增李斯特菌,用聚合酶链反应(PCR)检测其毒力基因prfA、plcB、hly、actA、iap、inlA;用脉冲场凝胶电泳(PFGE)技术进行分子分型及同源性分析;用多位点序列分型(MLST)技术进行分子分型和聚类分析。结果 55株单增李斯特菌全部携带prfA、plcB、hly、actA、iap、inlA基因;PFGE将其分为21个带型,相似度60.3%~100%;MLST将其分为14个ST型,ST9型为优势型别;3株病人分离菌株的PFGE带型和ST型互不相同,其中2株病人来源菌株分别与食品分离株具有相同PFGE带型和ST型。结论 阜阳市食品和病人中分离的单增李斯特菌均携带6个毒力基因,食品分离菌株的分子型别呈现出多样性,其中存在同型别单增李斯特菌持续性污染现象,病人分离菌株具有与食品来源菌株相同的PFGE带型和ST型,提示食源性感染的风险较高。     

杭州地区单核细胞增生李斯特菌食品分离株分子型别研究

目的研究杭州地区单核细胞增生李斯特菌(Listeria monocytogenes)食品分离株的分子分型情况,了解当地流行株的型别特征。方法用脉冲场凝胶电泳(PFGE)和多位点序列分型(MLST)的方法对单核细胞增生李斯特菌进行分子分型。PFGE结果进行聚类分析,并绘制MLST数据的最小生成树。结果 6个血清型组成的133株杭州食品分离株共获得19个MLST型别,并发现1个新的ST型ST767。ST9和ST121是数量最多的型别。用AscI和ApaI酶切分别获得33和45个PFGE带型。结论杭州地区单核细胞增生李斯特菌食品分离株分子型别分布广泛,大部分菌株是可引起人李斯特菌病的Lineage I和Lineage II菌株。食品中单核细胞增生李斯特菌的污染比较严重,应加强监测与管理以防食源性疾病的发生。     

杭州地区相同分子型别的单核细胞增生李斯特菌临床和食品分离株基因组分析

目的 研究杭州地区分子型别相同的临床和食品来源单核细胞增生李斯特菌在基因组水平的分子差异及进化关系。方法 利用高通量基因组测序和生物信息学分析方法对脉冲场凝胶电泳(Pulse-field gel electrophoresis,PFGE)型别一致的1株临床来源和6株食品来源的ST8型菌株进行基因组共线性、ncRNAs分布和毒力基因携带分析。联合NCBI Assembly数据库中ST8型菌株基因组,构建基于全基因组SNPs位点的进化树,进行溯源分析。结果 杭州地区临床和食品来源的菌株基因组共线性一致。菌株在毒力基因lmo0036和lmo2396的序列和rli48, rli62和rliG分子,质粒pLmA144的分布存在差异。基因组SNPs进化树显示ST8型菌株呈现高度同源。食品分离株中12-004与临床株12-103的进化上最接近,只有16个SNPs差异。结论 杭州市场近年肉类食品中存在遗传进化高度相似的一群ST8型单核细胞增生李斯特菌。杭州单核细胞增生李斯特菌临床分离株感染可能来自这群菌株。     

1例产后哺乳期腹泻患者分离单增李斯特菌的生物学特征分析

目的 分析1例单增李斯特菌所致产后哺乳期腹泻患者的临床特征、病原学、菌株的毒力基因携带及分子特征。方法 搜集病例的临床相关信息;采用选择性增菌和显色培养基分离单增李斯特菌,用VITEK- 2 COMPACT30 全自动细菌分析仪鉴定分离菌株,采用单增李斯特菌诊断血清对分离株进行血清分型,使用脉冲场凝胶电泳技术及多位点序列分型技术进行分子分型,应用PCR检测毒力基因,并用E-test方法检测分离菌株对5种抗生素的药物敏感性。结果 产后哺乳期患者食用甜瓜和冰箱冷藏的酸奶后引起不能自限的腹泻,检测结果证实病原为4b血清型、ST145序列型单增李斯特菌。分离菌株携带毒力基因plcB、act、hly、iap、prfA、inlA,对青霉素、氨苄西林、美罗培南、红霉素和复方磺胺均敏感。结论 单增李斯特菌引起的腹泻患者容易漏诊,加强孕妇等高危人群腹泻患者粪便标本中单增李斯特菌的检测,对于单增李斯特菌病病人的及时治疗,预防不良预后具有重要的公共卫生意义,尤其对这一特殊型别单增李斯特菌在我国引起的病例感染应引起重视,其可能的感染来源和致病风险值得进一步的研究。     

2013-2014年贵阳市感染性腹泻监测病例中沙门菌的病原学监测分析

目的 了解2013-2014年贵阳市腹泻监测病例中沙门菌的血清型别分布及脉冲场凝胶电泳(Pulse-Field Gel Electrophoresis,PFGE)分型特征,为贵阳市沙门菌病的防控提供科学依据。方法 收集2013-2014年贵阳市4家哨点医院感染性腹泻病例的432份粪便标本,对其进行沙门菌的分离培养、生化鉴定、血清分型及PFGE分型。结果 432例感染性腹泻患者的粪便标本共检出沙门菌35株,检出率为8.10%(35/432),男女检出之比为1.5:1,发病年龄主要集中在0~5岁;各季度间沙门菌检出率经Fisher确切概率法比较无统计学差异(P=0.052)。35株沙门菌分成9种血清型,其中优势血清型为肠炎沙门菌11株(占31.43%)和鼠伤寒沙门菌9株(占25.71%),其次克勒肯威尔沙门菌6株(占17.14%),斯坦利沙门菌3株,德尔卑沙门菌2株,阿贡纳沙门菌、婴儿沙门菌和病牛沙门菌血清型各1株,1株未分型。经XbaⅠ酶切后11株肠炎沙门菌分成8种PFGE型,优势型为JEGX01.CN0007;9株鼠伤寒沙门菌分成9种PFGE型,总体型别呈多样性分布。结论 贵阳市引起感染性腹泻的沙门菌以肠炎沙门菌和鼠伤寒沙门菌为主,PFGE型别呈多样性。     

中国小肠结肠炎耶尔森菌分布及分子流行病学特征

目的 通过中国1980-2019年不同地区小肠结肠炎耶尔森菌的病原学与PFGE分子型别特征分析,为小肠结肠炎耶尔森菌病的防控提供依据。方法 对中国不同区域,不同来源标本分离到的6 847株小肠结肠炎耶尔森菌,进行血清型别、生化表型、毒力基因分布研究,对致病性菌株进行脉冲场凝胶电泳(PFGE)分析。结果 小肠结肠炎耶尔森菌中致病性菌株2 047株、非致病菌4 800株。致病性菌株仅存在两种血清型,O∶3占比88.96%(1 821/2 047)、O∶9占比11.04%(226/2 047)。18个省市自治区的致病株以O∶3血清型为主,宁夏回族自治区以O∶9血清型为主。非致病菌血清型众多,普遍比致病株具有更多的阳性生化反应。1 821株O∶3致病株分为93个PFGE型别,分布于19个省市自治区,其中K6GN11C30021、K6GN11C30012为优势带型(分别占比46.35%、22.5%),75.38%的人源菌株与分离自当地的动物、食品菌株带型一致;226株O∶9致病株共分为14个PFGE型别,分布于8个省市自治区,77.78%人源菌株与分离自当地的动物、食品菌株带型一致。结论 我国小肠结肠炎耶尔森菌分布广泛、宿主众多,致病株仅有两个血清型,非致病株血清型众多、可能比致病株具有更强的生化代谢能力与环境适应力。致病性菌株PFGE优势带型相对集中,地域分布广泛,多数人源菌株与分离自当地的动物、食品菌株带型一致,应警惕通过家畜家禽、食品及外环境等多种来源感染人的风险。     

3例单增李斯特菌感染的病原学、临床及流行病学特征分析

目的 分析四川省自贡市2014年3例单增李斯特菌感染的临床特征及其病原学特征。方法 搜集临床病例信息;采用血清分型,脉冲场凝胶电泳技术和多位点序列分型方法对单增李斯特菌进行分子分型。结果 3例患者均为免疫力低下人群,有发热和败血症症状;3株单增李斯特菌中2株为1/2a血清型、ST8型,1株为1/2b血清型、ST778型,3株PFGE带型均不同。结论 免疫力低下人群易受单增李斯特菌侵袭性感染。通过与国内外食品及病人单增李斯特菌相关流行学资料比较,提示国外流行克隆群以及国内某些流行型菌株可引起国内李斯特菌病散发,甚至成为将来暴发的隐患。     

福氏志贺菌PFGE和MLVA分子分型方法的应用与评价

目的 比较和评价脉冲场凝胶电泳技术(PFGE)和多位点可变数目串联重复序列分析技术(MLVA)在福建地区福氏志贺菌研究中的应用。方法 运用PFGE和MLVA技术对43株分离自福建地区的福氏志贺菌进行分子分型,结合流行病学资料分析比较分型效果。结果 43株福氏志贺菌经PFGE分型后相似度在61.70%~100%之间,按照100%的相似水平可分为36个PFGE型,没有优势PFGE型别,分辨系数为0.992 2,存在4个优势簇(G1~G4);福氏志贺菌经MLVA分型后,按照100%的相似水平可分为41个MLVA型别,遗传关联度介于6.207％～100％之间,没有优势MLVA型别,分辨系数为0.997 8,得到5个优势基因群(Cluster1~5)。在最小生成树上,部分F4c与Fx亲缘关系较近,并都由F2a和F1a分支而来,表现出一定的遗传关系。结论 两种分型方法的分辨率基本一致,PFGE分型结果与流行病学背景资料及血清型别基本吻合,MLVA在分析菌株种群进化关系上更具优势。     

3例单增李斯特菌感染的病原学、临床及流行病学特征分析北大核心CSCD

目的分析四川省自贡市2014年3例单增李斯特菌感染的临床特征及其病原学特征。方法搜集临床病例信息;采用血清分型,脉冲场凝胶电泳技术和多位点序列分型方法对单增李斯特菌进行分子分型。结果 3例患者均为免疫力低下人群,有发热和败血症症状;3株单增李斯特菌中2株为1/2a血清型、ST8型,1株为1/2b血清型、ST778型,3株PFGE带型均不同。结论免疫力低下人群易受单增李斯特菌侵袭性感染。通过与国内外食品及病人单增李斯特菌相关流行学资料比较,提示国外流行克隆群以及国内某些流行型菌株可引起国内李斯特菌病散发,甚至成为将来暴发的隐患。     

北京市一些地区生肉标本中单增李斯特菌的分离及其分子流行病学特征分析

目的 了解北京市一些地区生肉中单增李斯特菌的污染情况及其分子流行病学特征。方法 采用北欧食品分析标准(NMKL)对北京市一些地区采集的340份牛、羊、猪、鸡和鸭生肉标本进行单增李斯特菌的分离鉴定,并对分离菌株进行血清学分型(Serotyping)、脉冲场凝胶电泳(Pulsed Field Gel Electrophoresis, PFGE)分型及多位点序列分型(Multilocus Sequence Typing, MLST)分析。结果 生肉标本中单增李斯特菌污染率为6.2%(21/340)。分离菌株含3种血清型(1/2a,1/2b和1/2c),以1/2c为优势血清型(占47.6%)。PFGE分析中,使用内切酶AscI酶切电泳将21株单增李斯特菌分为12个型别,可聚类为3个群。MLST分析将21株单增李斯特菌分为7个ST型,其中 ST9型最多(10株)。结论 北京市一些地区的生肉类食品中存在6.2%的单增李斯特菌污染率,这些单增李斯特菌以家系II菌株占据绝对优势(80.1%),其中1/2c型,GX6A16.CN0004和ST9型分别为血清型、PFGE带型以及MLST序列型的优势型别,与我国食源性单增李斯特菌的优势菌群特征一致。     

Genotypic characterization of Listeria monocytogenes isolated from humans in India

Listeria monocytogenes is a foodborne pathogen associated with severe diseases in humans and animals. The genotypic analysis of 17 L. monocytogenes isolates recovered from humans in India during 2006-2009 using multiplex serotyping PCR allowing serovar predictions, conventional serology and by pulsed field gel electrophoresis (PFGE) is presented. The isolates were recovered from patients exhibiting various clinical conditions. A multiplex-PCR based serotyping assay revealed 88·24% (15/17) of the strains belonging to the serovar group 4b, 4d, 4e and 11·76% (2/17) to the serovar group 1/2b, 3b. Conventional serology indicated that 13 (76·47%) L. monocytogenes isolates to be of serotype 4b, 2 (11·76%) serotype 4d, and 2 (11·76%) serotype 1/2b. Ten ApaI and nine AscI pulsotypes were recognized among the 17 human isolates. PFGE analysis allowed discrimination among isolates of the same serotype and among isolates from the same sampling areas or those isolated from different areas. Thus, PFGE together with multiplex-PCR serotyping allows rapid discrimination of L. monocytogenes strains. In addition, the predominance of L. monocytogenes serotype 4b is of concern, as this serotype has been most frequently associated with human listeriosis outbreaks.     

Genetic characterization of clones of the bacterium Listeria monocytogenes causing epidemic disease.

One hundred and seventy-five isolates of the pathogenic bacterium Listeria monocytogenes recovered from human clinical (blood and cerebrospinal fluid), animal, and environmental sources in Europe, North America, and elsewhere were analyzed electrophoretically for allelic variation at 16 genetic loci encoding metabolic enzymes. Forty-five distinctive allele profiles (electrophoretic types, ETs) were distinguished, among which mean genetic diversity per locus (H) was 0.424. Cluster analysis of a matrix of genetic distances between paired ETs revealed two primary phylogenetic divisions of the species separated at a distance of 0.54. ETs in division I were presented by strains of serotypes 4b, 1/2b, and 4a, whereas strains of ETs in division II were of serotypes 1/2a and 1/2c. Human and animal isolates did not represent distinctive subsets of ETs. The occurrence of linkage disequilibrium between enzyme loci and the widespread distribution of certain ETs indicate that the genetic structure of L. monocytogenes is clonal. One clone, marked by ET1, caused major epidemics of human disease in western Switzerland in the period 1983-1987 and in Los Angeles County, California, in 1985, both of which were attributed to contamination of soft cheese. ET 1 is closely related to the clone (ET7) that caused two large outbreaks of listeriosis in Massachusetts in 1979 and 1983.     

用PCR检测六类食品中单核细胞增生李斯特氏菌

目的　调查福建省食品中李斯特氏菌的污染状况。方法　用GB4789 30 - 94单核细胞增生李斯特氏菌 (Listeriamonocytogenes简称Lm)的检验方法分离菌株 ,用PCR检测李斯特氏菌的两种致病因子。结果　从福建采集 2 6 5份样品中分离出 17株李斯特氏菌 ,其中 ,2株Lm含有李氏溶血素O (ListerialysinO ,Hly)和内化素基因 (Internalin Inl) ,15株英诺克李斯特氏菌 (Listeria innocua)中 8株含有内化素基因 ,7株两种基因均为阴性。结论　从生鸡肉和生牛肉检出 2株Lm ,表明我省存在李斯特氏菌病的可能性 ,有必要进行深入研究。     

Five cases of listeriosis in the elderly

We reported five cases of listeriosis (sepsis and meningitis) in the elderly in our hospital during the last 4 years, where no cases of listeriosis had been found. These 5 cases had diabetes mellitus, lung cancer, chronic respiratory failure, gastric ulcer and aplastic anemia respectively as their underlying diseases. At the onset of listeriosis, 3 cases received corticosteroid and 3 cases received H2-blocker. 2 patients were cured and 3 patients died. Three autopsy cases had meningitis or meningoencephalitis and 2 cases of these autopsy cases had granulomatous changes in these spleens. In serotypes of Listeria monocytogenes (L. monocytogenes), 4 cases were 4b and 1 cases was 1b. All 5 strains were resistant to 3rd generation cephems. Wide uses of 3rd generation cephems and H2-blocker may be one of the reasons for the recent increase of listeriosis. Ingestion of contaminated food is the pathogenetic mechanism for initiating L. monocytogenes infections. And following the change of eating habits and the increase of imported foods, food-born listeriosis may increase. We suppose the increase of L. monocytogenes infections and must give attention to L. monocytogenes infections.     

The pathogenic potential of different pulsed-field gel electrophoresis types of Listeria monocytogenes strains isolated from food in Northeast Bosnia and Herzegovina

Listeria monocytogenes is often present in meat and meat products that are sold in the area of northeast Bosnia and Herzegovina. The major objective of this study was to examine the virulence of L. monocytogenes strains isolated from these types of food in that geographic area. Polymerase chain reaction was used to detect eight genes responsible for virulence of this pathogen, namely, prfA, inlA, inlB, hly, plcA, plcB, actA, and mpl. All examined isolates were confirmed to possess the eight virulence genes. Ten different pulsed-field gel electrophoresis (PFGE) macrorestriction profiles were recognized among 19 L. monocytogenes strains after restriction with two different endonucleases (ApaI and AscI). The pathogenicity of three different PFGE types of L. monocytogenes was confirmed through in vivo tests, which were performed on female white mice (Pasteur strain), and it ranged from 3.55 × 10(8) LD50 to 1.58 × 10(10) LD50. All of the three different PFGE types of L. monocytogenes were regarded as moderately virulent in relation to the reference strain L. monocytogenes Scott A. This result might be one of the reasons for the absence of reported listeriosis in northeast Bosnia and Herzegovina, despite the high degree of food contamination with this pathogen.     

Listeriosis in Iceland, 1978-2000: a description of cases and molecular epidemiology

The purpose of our study was to review all cases of listeriosis in Iceland during the period 1978-2000 and to analyse the genetic relatedness of their isolates. Case records of all patients in Iceland with listeriosis during the period were reviewed and the isolates compared using serotyping and pulsed-field gel electrophoresis (PFGE) using SmaI, AseI and ApaI restriction enzymes. Forty cases of listeriosis were diagnosed during the period, resulting in a mean annual incidence of 6.9 cases per million and a case fatality rate of 33%. In the first 5 y of the study only serotype 4b was observed; subsequently serotypes 1/2a and 1/2b appeared and serotype 4b declined in prevalence. PFGE yielded 24 different genotypes with 7 clusters of indistinguishable genotypes, each comprising 2-6 cases. During 1992-95 the annual incidence of listeriosis in Iceland rose to 15 cases per million. This was largely due to 2 clusters, 1 of 3 cases and the other of 6. No cases of listeriosis were diagnosed during 1998-2000. Our data show an increased number of cases within clusters in the latter half of the period. At the same time, food processing and distribution has become increasingly centralized in Iceland, suggesting an increased risk of listeriosis outbreaks.