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1.
A large outbreak of acute watery diarrhoea involving all age groups of mongoloid tribal aborigines occurred during October-November, 2002 in the Nancowry group of Andaman and Nicobar Islands in the Indian Ocean. Twenty-one of the 67 stool samples from 67 patients were positive for toxigenic Vibrio cholerae O1, serotype Ogawa biotype El Tor, which showed striking similarity in its antibiogram with some of the strains of V. cholerae O1 Serotype Ogawa biotype El Tor isolated in Kolkata. The Nancowry and Kolkata isolates were compared with molecular tools involving random amplified polymorphic DNA (RAPD) fingerprinting, ribotyping and pulsed-field gel electrophoresis (PFGE). RAPD fingerprinting and ribotyping techniques revealed that all the V. cholerae strains associated with the outbreak in these islands were clonal in nature and identical to a population of isolates obtained from Kolkata since 1993. PFGE could discriminate within these Kolkata isolates further and established that a particular subtype of this population reached the remote Nancowry islands and was responsible for the outbreak.  相似文献   

2.
Restriction fragment length polymorphism (RFLP) analysis of total DNA and of ribosomal DNA (rDNA) regions (ribotyping) were used to document Streptococcus pyogenes vertical mother-to-infant transmission and to investigate the spread of S. pyogenes in an obstetric unit. Two isolates from a newborn, two isolates from his mother (patient 1), and two isolates from two other mothers (patients 2 and 3) were studied. RFLP of total DNA, both after HindIII and PvuII digestions and ethidium bromide staining, gave indistinguishable patterns for the strains isolated from the neonate, his mother, and patient 2. Strains from patient 3 and six unrelated strains studied for comparison showed different patterns. In our system, ribotyping was less discriminative than total DNA RFLP analysis. DNA RFLP analysis therefore provides a valuable molecular tool for studying S. pyogenes epidemiology.  相似文献   

3.
The constancy of strain genotypes of multiple isolates of Burkholderia pseudomallei from 13 patients with melioidosis was examined by Bam HI ribotyping and pulsed-field gel electrophoresis (PFGE) of Xba I digests of DNA. Seven of 8 patients with single episodes of melioidosis each yielded genetically identical isolates and only one of five patients with recurrent episodes was infected with a new strain clearly distinct from the original primary strain. Variation was observed in PFGE patterns of primary and relapse isolates of another patient but this was insufficient to define genetically distinct strains. We conclude that most patients with single or multiple episodes of melioidosis retain a single strain.  相似文献   

4.
Primary V. vulnificus septicemia has been continuously reported in Korea. We analyzed the molecular diversity of V. vulnificus strains isolated from clinical specimens using pulsed-field gel electrophoresis (PFGE) and random amplified polymorphic DNA (RAPD) analysis. We analyzed a total of 23 V. vulnificus strains isolated from 22 patients between 1992 and 1997. RAPD analysis was performed using five random primers, and we obtained chromosomal DNA restriction patterns with NotI and SfiI by PFGE. Two isolates from one patient disclosed similarity value 1.0 by RAPD and had an indistinguishable pattern when analyzed with PFGE, which indicated that they were the same strains. The remaining 22 isolates from 22 patients could be separated into 5 different molecular types in RAPD analysis. The range of similarity values among the isolates was wide (0.29-0.81). Of 22 strains, four strains could not be typed in repeated trials by PFGE with NotI and SfiI. The PFGE patterns of 18 strains showed a remarkable polymorphism consisting 12-19 fragments (20-870 kb). These results show that V. vulnificus strains isolated from Korea are genetically diversified for the most part.  相似文献   

5.
目的 对来自贵州省的8例空肠弯曲菌病疑似病例进行病原学诊断与分子流行病学特征分析,为病例的确诊和贵州省空肠弯曲菌病疫情的预防和控制提供科学依据。方法 对8例疑似病例粪便和血液标本进行细菌分离,采用传统方法和多重PCR方法对空肠弯曲菌可疑菌株进行鉴定,应用脉冲场凝胶电泳分型技术(PFGE)对空场弯曲菌分离株进行分析。结果 8例空肠弯曲菌病疑似病例标本均分离出空肠弯曲菌可疑菌株,PCR扩增出空肠弯曲菌预期大小的目的基因片段,PFGE显示8株菌经SamI酶切后产生7~10条DNA条带,聚类分析显示,8株菌株分为7个PFGE带型,8株菌的相似性>50%,其中GZ201004和GZ201005两株腹泻病例来源分离株相似性为100%,血培养血液标本分离株GZ201201与粪便标本分离株GZ201007相似性为66.7%。结论 8例空肠弯曲菌病疑似病例均检出空肠弯曲菌,PFGE显示GZ201004和GZ201005两株为同一来源,但8例病例来源菌株存在PFGE带型多态性,该研究结果为病例的确诊和疫情的预防和控制提供了科学依据。  相似文献   

6.
We analyzed the restriction fragment length polymorphism (RFLP) of total DNA and of ribosomal DNA regions (ribotyping) to document the occurrence of endogenous, systemic bacteremia and meningitis due to Enterobacter cloacae in a newborn. Five strains of E. cloacae were isolated from this newborn. Three of these strains were recovered from stool at counts of 10(8), 10(9), and 10(9) organisms/g of feces, respectively; one strain was isolated from blood; and one strain was isolated from cerebrospinal fluid. In addition, five epidemiologically unrelated strains of E. cloacae were studied for comparison. Our study clearly shows the genetic relatedness of the strains isolated sequentially from cultures of stool, blood, and cerebrospinal fluid. RFLP analysis of total DNA and ribotyping seem particularly well suited to the study of the epidemiology of nosocomial E. cloacae strains.  相似文献   

7.
OBJECTIVES: We aimed to study the antimicrobial susceptibilities and molecular epidemiology of Salmonella enterica serotype Derby, a unique and common salmonella serotype in Hong Kong. METHODS: Salmonella Derby strains isolated from stools of patients in a large general hospital in Hong Kong from 1989 to 1994 and from food samples isolated in the Public Health Laboratory were randomly selected and investigated for the antimicrobial susceptibilities by determining the minimal inhibitory concentrations of 19 antimicrobial agents and their relatedness using plasmid analysis, ribotyping, pulsed-field gel electrophoresis (PFGE) and total DNA fingerprinting. RESULTS: About 50% of the 127 isolates studied were susceptible to all the 19 antibiotics tested, although resistance to tetracycline (49%) and sulfamethoxazole (38%) was high. Only 12% did not harbour any detectable plasmids, while the rest contained plasmids in 51 profiles. There were two predominant clones, one comprising of 35% of isolates that could not be pulsotyped because discrete bands were not discernible after PFGE and another comprising 34% of isolates that could be pulsotyped. The remaining 31% belonged to a variety of types. CONCLUSIONS: Approximately 70% of S. Derby belonging to two clones were endemic in the community, while the remaining isolates belonged to a variety of types which were probably a result of sporadic infection. The sources of human infections were foods, since most isolates from foods also belonged to the two endemic clones. Typing of S. Derby isolates from other sources such as animals or the environment would help elucidate how foods were contaminated. PFGE might not be universally applicable to all salmonella strains.  相似文献   

8.
目的应用脉冲场电泳(PFGE)分型技术和16S rRNA基因测序分析技术分别对贵州省3株动物宿主钩 端螺旋体分离菌株进行分子分型和基因种鉴定,了解贵州省钩端螺旋体的分子流行病学特征。方法应用 DNA限制性内切酶Not I对钩端螺旋体染色体DNA酶切后,用PFGE将DNA片段分离,采用BionumericsV4.0将3 株钩体菌株PFGE图谱与中国15群15型参考菌株进行聚类分析;同时,应用PCR扩增几乎全长的钩体16S rRNA基因片段,并将扩增产物进行双向序列测定,并与GenBank数据库已注册的核酸序列进行同源性比对 、确定基因种、分析亲缘进化关系。结果来自贵州省的3株动物宿主分离钩体菌株PFGE带型命名为LepNot I 002和LepNot I 003,经聚类分析,3株菌株与黄疸出血群黄疸出血型赖株的相似性大于95%。16S rRNA 基因测序和分析表明,3株贵州分离钩体菌株之间的同源性为100%,与致病性钩体问号钩端螺旋体种(L. interrogans)不同血清型参考菌株的同源性达100%。结论3株贵州动物分离钩体菌株经PFGE分型鉴定与黄 疸出血群赖型赖株的相似性大于95%,经16S rRNA基因测序分析鉴定为L. interrogans种,上述两种方法 对贵州省钩体分离菌株的鉴定结果一致,有助于贵州省钩端螺旋体病的主动监测、暴发调查和传染源追踪 。  相似文献   

9.
After isolation of multiresistant (MR) Pseudomonas aeruginosa from 3 hospitalized patients in a paediatric intensive care unit (PICU), a prospective surveillance programme was established to detect infected and/or colonized patients in the hospital. Isolates were examined by means of outer membrane protein (OMP) profiles, serotyping and DNA genomic analysis using pulsed-field gel electrophoresis (PFGE). Fifty-five P. aeruginosa strains were isolated from 23 hospitalized patients during September and October 1997. The median hospital stay before isolation of P. aeruginosa was 8 d. PFGE demonstrated that the same clone infected 14 patients, 4 of whom were not hospitalized in the PICU. Susceptibility patterns and OMP profiles correlated with PFGE results in 37.8% and 36.4% of cases, respectively. Serotype O11 correlated with pattern A in 77% of cases and serotype O4 correlated with unrelated strains in 75% of cases but did not discriminate between outbreak and unrelated isolates. Extensive investigation of cultures failed to identify a reservoir of P. aeruginosa. PFGE was superior to OMP analysis and serotyping for discriminating between strains. The possible mode of acquisition for most of the patients infected with the same clone was cross-contamination.  相似文献   

10.
Analysis of restriction fragment length polymorphism (RFLP) of total DNA and of ribosomal DNA (ribotyping) was used to document four cases of Streptococcus agalactiae mother-to-infant transmission potentially associated with ingestion of infected mother's milk. Twenty strains were analyzed. Ten strains were mother-baby pairs, five from the milk of five mothers, four from their neonates with late-onset infection, and one from a colonized neonate. All mothers had early postpartum mastitis. Ten unrelated strains were studied for comparison. In each case, the two strains of each mother-baby pair produced identical RFLP patterns of total DNA. The 10 unrelated strains generated 10 different patterns, one of which, though, was observed in one of the mother-baby pairs. Ribotyping was less discriminative than total DNA RFLP analysis (6 different patterns vs. 13). These data extend the evidence for breast milk transmission in S. agalactiae late-onset neonatal infection.  相似文献   

11.
BACKGROUND: Vancomycin resistance among enterococci is an emerging nosocomial problem. Consequently, it is important to understand the distribution of vancomycin-resistant enterococci (VRE) within and between hospitals to implement appropriate infection control measures. METHODS: In this study, 116 VRE isolates obtained from patients in 6 New York State hospitals were analyzed by antibiotic susceptibility testing, pulsed-field gel electrophoresis (PFGE) fingerprinting, plasmid profile analysis, vanA and vanB polymerase chain reaction, and DNA:DNA hybridization with vanA and vanB probes. RESULTS: PFGE and plasmid typing generally agreed, but plasmid profiles were more variable. These analyses revealed that genetic heterogeneity among isolates from within each of the 6 hospitals varied considerably. Among 23 Enterococcus faecium isolates from one hospital, there were only 3 PFGE types, and 20 isolates had the same type. However, in another hospital, each isolate was genetically distinct. Closely related strains were not found in separate hospitals. VRE strains with vanA genes and strains with vanB genes were found in 3 hospitals. Both plasmid and chromosomal carriage of these genes was detected. CONCLUSIONS: PFGE typing showed that nosocomial VRE transmission had occurred in some hospitals. However, there was no evidence for it in others. Neither was there evidence for intrahospital transmission or for emergence of an endemic strain. These observations demonstrate that it is important to evaluate genetic heterogeneity among VRE before implementation of infection control measures. PFGE is the method of choice for epidemiologic typing, but polymerase chain reaction, plasmid, and hybridization studies can provide important information concerning the presence and potential for transfer of vancomycin resistance genes.  相似文献   

12.
目的 对2015-2017年聊城地区主动监测哨点医院腹泻患者中分离到的沙门氏菌进行病原学分析,了解沙门氏菌的感染现状及血清型分布、分子分型特征和耐药情况。方法 对2015-2017年分离自腹泻患者的41株沙门氏菌进行脉冲场凝胶电泳(PFGE)和药物敏感性测试,并用BioNumerics软件分析菌株之间的相似度,用微量肉汤稀释法进行菌株耐药性检测。结果 腹泻患者中沙门氏菌总分离率为7.16%,且不同年龄段分离率存在差异。分离的沙门氏菌共有8个血清型,其中鼠伤寒沙门氏菌和肠炎沙门氏菌分别为18株和7株,为优势血清型;PFGE分析发现41株菌共产生了34种不同的PFGE带型,相同血清型的沙门氏菌的PFGE带型比较相近,不同血清型的PFGE带型具有多态性,未发现菌株成簇存在现象。测试菌株对四环素耐药率最高为73.17%,多重耐药率达68.29%,发现6株携带不同耐药基因类型的产广谱β-内酰胺酶的鼠伤寒沙门氏菌。结论 聊城地区沙门氏菌具有一定的血清型及遗传的多样性,高耐药和多重耐药现象严重,应加强病例及环境联合耐药监测。  相似文献   

13.
Objective To examine the clonal diversity of vancomycin‐resistant enterococci (VRE). Methods A total of 900 clinical isolates of enterococci were obtained, and VRE isolates were subjected to antimicrobial susceptibility tests, biochemical fingerprinting with the PhPlate system (PhP), ribotyping and pulsed‐field gel electrophoresis (PFGE) typing. Results Forty‐nine of all enterococcal isolates were resistant to high levels of vancomycin (MIC ≥ 128) and identified as Enterococcus faecium. Biochemical fingerprinting with PhP showed that the VRE isolates were highly diverse (diversity index, Di = 0.93) and belonged to 24 PhP‐types. The VRE could be separated into 34 and 27 types with PFGE and ribotyping, giving diversity indices of 0.98 and 0.97, respectively. The PFGE method was more discriminatory than ribotyping and PhP system for E. faecium isolates. A combination of either of the two typing methods resulted in at least 44 types. Furthermore, sequencing analysis of vanS of Tn1546 showed one nucleotide mutation (C→A) at position 5727 in comparison with the prototype BM4147, which was found to be unique in all Iranian VRE isolates. Conclusion The isolated clinical VRE strains were highly diverse in Tehran.  相似文献   

14.
To clarify the route and source of Vibrio vulnificus infection, we conducted molecular epidemiological investigation by DNA analysis of 355 environmental isolates (seawater-derived strain: 86, sea mud-derived strain:36, and oyster-derived strain: 233) and 65 human clinical isolates, for a total of 420 isolates, using pulse field gel electrophoresis (PFGE), with the following results. 1. When DNA was cleaved with 2 enzymes, Not I and Sfi I, and subjected to PFGE, Not I DNA interpretation was 76.9%, and Sfi I cleavage was 97.9%, showing that Sfi I was superior in cleaving DNA of this bacteria. 2. Sfi I-interpreted strains were subjected to PFGE and migration patterns were analyzed by UPGMA, but close classification was not possible because similarity was low, this infectious disease clearly originated from multiple rather than a single-clone. In this cluster, we concluded that this infectious disease was acquired through contact between the environment and human beings and viceversa. We identified an assortment of clinical isolates and environment-derived strains among more than 89% of strain groups tested, none of which could be expected to have the same origin. We conclued DNA analysis on these two types of restriction enzymes using PFGE, but were unable to classify test results in detail due to the proliferation of migration patterns and low degree of similarity.  相似文献   

15.
The usefulness of an automated ribotyping system (RiboPrinter) was evaluated for characterizing and identifying clinical isolates of 37 verocytotoxin-producing Escherichia coli (VTEC) strains and 16 non-VTEC strains. All strains were successfully ribotyped with satisfactory reproducibility and stability and characterized into 10 different ribogroups. All VTEC O157 strains were characterized into a specific ribogroup and correctly typed into the specific DuPont ID for VTEC O157:H7, while all of the non-VTEC O157 strains were clearly distinguished from VTEC O157. VTEC O26 and O111 strains, the most prevalent VTEC serotypes after O157, were also well characterized into specific ribogroups and identified. These results suggest that the RiboPrinter may have an advantage over other typing systems in that it can rapidly and easily discriminate VTEC from non-VTEC strains of the most prevalent VTEC serotypes in Japan, even though it provides a lesser degree of discrimination than pulsed-field gel electrophoresis (PFGE). With a hierarchical or sequential typing combining the RiboPrinter and PFGE, rapid and accurate typing can be achieved during an outbreak of VTEC, which may be useful in clinical and public health settings.  相似文献   

16.
目的 了解不同血清群致病性钩体的脉冲场凝胶电泳(pulsed-field gel electrophoresis,PFGE)带型特征。方法 应用PFGE方法对65株不同血清群致病性钩体国际、国内参考菌株和疫苗株进行分型,并以此聚类分析,同时与菌株的多位点序列分型(multilocus sequence typing,MLST)、多位点串联重复序列数变化分析(multilocus VNTR analysis, MLVA)分型结果进行比较研究。结果 不同血清群致病性钩体基因组DNA经NotⅠ酶切电泳后,获得了较高清晰度酶切图谱,各条带分离良好。65株钩体菌株分为61种PFGE型别。相同的血清群的钩体菌株的PFGE型别不尽相同。比较分析结果显示尽管PFGE、MLST和MLVA之间的分型结果不尽相同,但都具有较高的分辨率。聚类分析显示这些菌株可形成11个大小不一进化簇,呈现多点分散进化特征。结论 获得致病性钩体分子分型的第一手资料,为后续钩体分子溯源及流行病学研究提供科学指导。  相似文献   

17.
目的运用脉冲场凝胶电泳(PFGE)对一起食物中毒中分离的菌株进行同源性分析,为查明原因和溯源提供依据。方法采集患者、食品从业人员、环境样本以及留样食品进行分离、鉴定,对分离的菌株进行PFGE分析。结果本次事件共采集137份样本,检出11株副溶血性弧菌,其中5株来自病人样本,3株来自冷菜间厨师样本,1株来源于生扇贝样本,2株分别来自龙虾池、桂鱼池养殖水。11株菌株经PFGE分析,除1株患者样本与其余10株的同源性为60.0%外,其余10株副溶血性弧菌的同源性为100.0%。结论 PFGE分型技术揭示菌株之间的流行病学联系,为事件的分析和追溯来源提供分子流行病学证据。  相似文献   

18.
目的 对2017-2020年济南市哨点医院腹泻患者中分离到的沙门氏菌进行病原学分析,了解济南市腹泻患者沙门氏菌的血清型分布特征、分子分型特征及耐药情况。方法 分别利用血清检测试剂盒和脉冲场凝胶电泳技术(PFGE)对来自济南市各医院腹泻门诊病人的的90株沙门氏菌进行血清分型和分子分型分析,酶切电泳图谱导入BioNumerics软件进行聚类分析;利用微量肉汤稀释法对40株沙门氏菌进行耐药性检测。结果 90株沙门氏菌可分为27个血清型,鼠伤寒沙门氏菌和肠炎沙门氏菌为优势血清型,分别占总数的47.78%和17.78%。PFGE电泳后产生的带型具有多态性,以鼠伤寒沙门氏菌和肠炎沙门氏菌的带型最为集中;药敏结果显示,沙门氏菌对氨苄西林耐药率最高,为72.50%,多重耐药率达67.50%。结论 济南地区沙门氏菌具有血清型多样化和遗传多样性特征,对抗生素的高耐药和多重耐药现象严重,应加强济南地区耐药检测。  相似文献   

19.
目的 研究确定呼吸重症监护室(RICU)内机械通气患者连续发生嗜麦芽窄食单胞菌(pma)感染为暴发感染,并追踪其感染源。方法 收集2002年12月至2003年2月自RICU有创机械通气患者气道抽吸物中分离出的9株pma菌株,RICU工作人员手拭子分离的pma菌株2株,纤维支气管镜(已按常规消毒存放,用于气道管理)冲洗液分离的pma菌株2株,采用WHONET5软件通过耐药分析组合对菌株进行抗生素型分析,通过脉冲场凝胶电泳(PFGE)全DNA指纹图技术对菌株进行分子分型,确定菌株的亲缘关系。以1997年至2000年自多个科室收集的16株pma作对比。结果 9例机械通气患者感染的9株pma,有8株PFGE基因型相同,并与2株分离自RICU工作人员手拭子的pma和2株分离自纤维支气管镜的pma基因型一致。抗生素型则有7株分型相同。抗生素型与PFGE基因型的符合率为85%(11/13)。1997年至2000年收集的16株pma,PFGE基因型分为11型,抗生素型分为9型,呈现为多克隆构成模式。结论 8例机械通气患者感染的pma来自于同一克隆,RICU内存在着pma的暴发感染。消毒不彻底的纤维支气管镜和医护人员的手污染是引起本次暴发感染的重要感染源和感染途径。  相似文献   

20.
In order to evaluate reliability of pulsed-field gel electrophoresis (PFGE) analysis performed at different prefectural public health institutes (PHIs) for use in the PulseNet Japan surveillance system to detect enterohemorrhagic Escherichia coli O157, we compared the results of PFGE-typing of 14 selected strains of O157 performed at 8 selected PHIs to evaluate the reliability of different experimental protocols used in these PHIs. PFGE was performed for 14 strains for which there were 14 PFGE types in 3 PHIs, and 13 PFGE types in 5 PHIs by using their own protocols and/or those of the National Institute of Infectious Diseases (NIID). PFGE fingerprints from 5 out of the 8 PHIs were successfully genotyped for all of the 14 strains. A PFGE fingerprint from one PHI was successfully genotyped when the NIID pulsing protocol was used, but was not genotyped when the PHI's own protocols were used. PFGE fingerprints from 2 PHIs failed to be genotyped for one each of the strains. The cause of this genotyping failure was considered to be inappropriate PFGE pulsing protocols or inadequate digestion of chromosomal DNA. These results suggest that PFGE protocols should be standardized for the establishment of PulseNet Japan.  相似文献   

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