• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 81
  • 31
  • 24
  • 13
  • 7
  • 6
  • 5
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 201
  • 201
  • 41
  • 22
  • 20
  • 19
  • 17
  • 17
  • 15
  • 14
  • 14
  • 13
  • 13
  • 12
  • 12
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Emergence and Molecular Characterization of NAP4 Clostridium difficile Healthcare-Associated Infections in Canada

Tyler, Kosowan 13 September 2016 (has links)
Clostridium difficile is an important nosocomial pathogen and the leading cause of antibiotic-associated diarrhea. In the early 2000's, major outbreaks of C. difficile occurred in the Canada and the United States, both caused by the same strain, the North American Pulsed-Field type 1 (NAP1). Recently a steady rise in prevalence of a NAP4 strain was observed. This study utilized phenotypic and genotypic methods, including whole genome sequencing, to fully characterize and better understand the emergence of NAP4 in Canada. Through WGS it was revealed that an emerging NAP4 PFGE type (PFGE type 0033) has acquired a novel phage (phiCD505), which harbors transcriptional regulators and is inserted in close proximity to a GMP synthase gene. The role of these phage encoded transcriptional regulators on C. difficile virulence factors and/or disruption of normal expression of GMP synthase remain to be elucidated, but might be contributing to the emergence of this PFGE type. / October 2016
2

The localization of two epitopes recognized by the monoclonal antibody PCG-4 on toxin A of Clostridium difficile /

Frey, Steven M., January 1990 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1990. / Vita. Abstract. Includes bibliographical references. Also available via the Internet.
3

The epidemiology and control of Clostridium difficile infection in a Western Australian hospital /

Thomas, Claudia. January 2003 (has links)
Thesis (Ph.D.)--University of Western Australia, 2003.
4

Outcomes and expenditures of clostridium difficile infection in pediatric solid organ transplant recipients

Ling, You-Li 10 October 2014 (has links)
The main purpose of this study was to assess outcomes (i.e., inpatient mortality, transplant failure or rejection, colectomy, and hospital length of stay) of clostridium difficile infection (CDI) and the association of expenditures (i.e., charges and costs) and CDI in pediatric solid organ transplant (SOT) recipients. Data from the 2000, 2003, 2006, and 2009 Kids’ Inpatient Database (KID) files were used to identify events with SOT- related ICD-9-CM diagnosis codes. Logistic regression was used to assess the association of CDI and dichotomous outcome variables, while log-linked gamma regression models were used to assess the association of CDI and continuous outcome variables. Methods accounting for the complex survey sample design of the KID were used when performing all statistical analyses. The total number of pediatric SOT hospital events was 48,286. The overall prevalence of CDI for pediatric SOT hospitalizations was 1.76%. For SOT hospitalizations with CDI, inpatient mortality was 1.63%; the prevalence of transplant failure or rejection events was 27.71%; the prevalence of a colectomy was 4.86%. The median hospital length of stay was seven days; the median charge and cost for each hospitalization was $48,409 and $17,412, respectively. The results showed that CDI was not significantly associated with inpatient mortality or transplant failure/ rejection in pediatric SOT hospitalizations. SOT patients with CDI were 2.6 times more likely to have a colectomy than SOT patient without CDI. The mean hospital length of stay (LOS) for a SOT admission with CDI was approximately 2 times the mean LOS for a SOT admission without CDI. The mean charges and the mean costs for a SOT admission with CDI was approximately 2 times that for a SOT admission without CDI. In conclusion, CDI diagnoses were not significantly associated with higher inpatient mortality or transplant failure/ rejection for pediatric SOT hospitalizations. But CDI was significantly associated with a higher prevalence of a colectomy, longer hospital LOS, higher charges, and higher costs (all p<0.05). To avoid substantially higher expenditures and health care utilization, CDI in pediatric SOT recipients should be prevented when possible and promptly diagnosed and treated when it occurs. / text
5

Temporal and spatial explorations of Clostridium difficile variable number tandem repeats

SaidQasem, Osama January 2014 (has links)
Clostridium difficile infection (CDI) has recently emerged as a major health problem. An understanding of the micro-epidemiology of the infection is decisive for the design and implementation of control polices. Presently, typing using PCR ribotyping (RT), Multi-locus Sequence Typing (MLST) and Multi-locus Variable Number Tandem Repeat Analysis (MLVA) can be used to investigate recent transmission events of C. difficile. In the case of MLVA, different criteria have been used to classify strains and this reflects inconsistencies in the contemporary knowledge of change in MLVA polymorphisms. In this study, temporal and spatial investigations were conducted to better understand the dynamics of change in C. difficile VNTR loci. The 164 isolates from the collection yielded 25 different STs, with ST161 and ST171 being newly described. The congruence of MLST to the other typing methods of RT and tcdC, strengthens the robustness of discrimination of these methods. Sub-typing using MLVA, however yielded 139 strains, and again there was congruence to the aforementioned methods. Clustering of MLVA strains into groups revealed Single and Multi-Isolate Strains linked together as single locus variants with groups coordinating with MLST types within ST1 and ST3. The lowest MLVA diversity was seen in the Period of Increased Incidence and was primarily responsible for high incidence rates. These groups of MLVA related isolates were used to characterise the instability of the repeat sequences of MLVA loci. 2 Locus differences were examined from the perspective of the genetic role of the locus, DNA polymerase amplification, the impact of different growth conditions on the fitness of the repeat sequences and of the frequency of repeat changes in the natural population. These studies have focused on the on the drivers of change of VNTR loci in general and will allow a more rational approach to using MLVA loci in epidemiological studies.
6

Molecular characterization of toxigenic clostridium difficile by multiplex and real-time PCR

Chan, Chi-chiu, Elvin., 陳志超. January 2011 (has links)
published_or_final_version / Microbiology / Master / Master of Medical Sciences
7

Molecular characterization of clostridium difficile isolates by capillary gel electrophoresis-based PCR ribotyping

Lam, Ching-to., 林正道. January 2012 (has links)
Backgroud: Clostridium difficile infection (CDI) is a global concern since the emergence of the hyper-virulent strain NAP1/BI/027. The incidence of CDI has been increasing and active surveillance of Clostridium difficile epidemiology is of paramount importance. In studying the epidemiology of CDI, PCR ribotyping is a very useful method in finding the genetic relatedness of outbreak and epidemic strains. Characterisation of Clostridium difficile isolates can help surveillance and active monitoring, hence reducing the chance of potential outbreaks. Aim: The aims of this study is to investigate the epidemiology of Clostridium difficile in Hong Kong in the year 2010, and that of a Clostridium difficile outbreak in 2011 by using capillary gel electrophoresis-based PCR ribotyping. Results: Among the 307 toxigenic isolates, 139 isolates (45.3%) were characterized as existing ribotypes. Ribotype 012 was the predominant ribotype (17.3%), followed by ribotype 002/0 (15.6%). A total of 144 isolates (46.9%) were characterized as new ribotypes. The remaining 24 isolates (7.8%) were characterized as of high resemblance of existing ribotypes. A total of 8/12 isolates (66.7%) of the outbreak strains were found to be ribotype 002/0. Conclusion: The predominant strains of Clostridium difficile in 2010 was ribotype 012. The 2011 outbreak in Kowloon Hospital was an outbreak of Clostridium difficile ribotype 002/0. Capillary gel electrophoresis-based PCR ribotyping was showed to be a useful tool in investigation of Clostridium difficile outbreaks and study of Clostridium difficile epidemiology. / published_or_final_version / Microbiology / Master / Master of Medical Sciences
8

Molecular characterization of clostridium difficile PCR ribotypes R-002 and R-017 causing outbreaks and sporadic diarrhea

Ng, Pik-yi, 吳碧儀 January 2014 (has links)
Introduction: Clostridium difficile infection (CDI) is the major bacterial agent causing hospital-acquired diarrhea. The incidence and severity of CDI has increased significantly in recent decades. The distribution of PCR ribotype varies among the countries. PCR ribotype 017 and 002 are the predominant ribotypes in China and Hong Kong respectively. Molecular characterization of C. difficile isolates is useful for outbreak investigation and surveillance. Both PCR ribotyping and Multilocus variable-number tandem-repeat analysis (MLVA) are reliable molecular tools for characterization of C. difficile from outbreak and sporadic case. MLVA allows subtyping of genetically related C. difficile isolates of the same ribotype by their distinctive MLVA patterns. The aim of this study was to characterize the outbreak and sporadic C. difficile isolates of PCR ribotype 002 and 017 by using capillary gel electrophoresis-based PCR ribotyping and MLVA. Their cytotoxicity, sporulation rate and germination efficiency were also investigated in the study. Results: A total of the 26 C. difficile isolates were identified by PCR ribotyping including fifteen isolates of PCR ribotype 002, eight isolates of ribotype 017, and three isolates of other ribotypes. The isolates of the same ribotypes were further sub-typed into outbreak and sporadic cluster. All isolates showed toxin-producing capability. The sporualtion rates of outbreak isolates of PCR ribotype 002 were significantly higher than that of sporadic isolates of PCR ribotype 002. Statistically higher sporulation rate was also observed in the outbreak isolates of PCR ribotype 017. The germination rate was also statistically higher in the outbreak isolates of PCR ribotype 002 than the sporadic cases. Conclusion: Capillary electrophoresis-based PCR ribotyping identified fifteen C. difficile PCR ribotype 002 and eight PCR ribotype 017 in this study. MLVA then refined these isolates into two corresponding sub-groups of outbreak and sporadic isolates. Higher sporulation and germination rates were observed in the outbreak isolates. Sporadic isolates demonstrated relatively lower sporulation and germination rates. The current evidences correlate the genotypic characterization to sporulation activity and germination efficiency. / published_or_final_version / Microbiology / Master / Master of Medical Sciences
9

Genomic variation and evolution of Clostridium difficile

He, Miao January 2012 (has links)
No description available.
10

Defining the Clostridium difficile spo0A regulon and its role in disease and transmission

Pettit, Laura Jane January 2012 (has links)
No description available.

Page generated in 0.1001 seconds