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Author: Yuen-Yi Fan
Publisher: Open Dissertation Press
ISBN: 9781374664661
Category :
Languages : en
Pages :
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Book Description
This dissertation, "Ecoepidemiology of Laribacter Hongkongensis, a Novel Bacterium Associated With Community-acquired Gastroenteritis" by Yuen-yi, Fan, 范婉儀, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled "Ecoepidemiology of Laribacter hongkongensis, a Novel Bacterium Associated with Community-acquired Gastroenteritis" Submitted by Fan Yuen Yi for the degree of Master of Philosophy at the University of Hong Kong in August 2006 Laribacter hongkongensis, a recently discovered bacterium associated with community-acquired gastroenteritis, has been found in the intestines of freshwater fish. To better understand the epidemiology and ecology of the bacterium, a surveillance study was carried out to investigate seasonal variation in the recovery of L. hongkongensis in retail freshwater fish intestines in Hong Kong. In this study, intestines from 120 grass carps were sampled during a one-year period. L. hongkongensis was isolated from 49 (41%) of 120 grass carps. Seasonal variation in the recovery of L. hongkongensis was observed, with higher isolation rates in spring and summer than in fall and winter. There was also positive correlation between ambient temperature and the isolation rates. When L. hongkongensis was cultured in vitro at different temperatures, shorter lag time and higher growth rate were observed at higher temperatures, with 37C being optimal among the tested temperatures. Although freshwater fish has been found to be the reservoir of L. hongkongensis, little is known about its survival in aquatic environment. To investigate the presence of L. hongkongensis in fresh water environments, a one-year surveillance study was carried out in ten drinking water reservoirs in Hong Kong. L. hongkongensis was isolated from six of the ten reservoirs, including Pok Fu Lam reservoir, Tai Tam reservoir, Aberdeen reservoir, Kowloon reservoir, Shek Lei Pui reservoir and Shek Pik reservoir. Again, seasonal variation was observed, with higher recovery rates in summer and during days with higher water and ambient temperatures. Of 27 freshwater fish collected from six reservoirs, L. hongkongensis was recovered from two fish collected from two reservoirs. Overall, 35 different pulsed-field gel electrophoresis patterns, different from those previous isolates from human and freshwater fish from retail food markets, are found among the total of 61 isolates. Isolates of L. hongkongensis were shown to grow in autoclaved water samples collected from reservoir, supporting that the bacterium can survive in water environments free of freshwater fish. This is the first study to demonstrate the presence of L. hongkongensis in natural water environments. ------Total word count: 333------ 2 DOI: 10.5353/th_b3734418 Subjects: Neisseriaceae - Ecology - China - Hong Kong Gastroenteritis Laribacter hongkongensis
Author: Yuen-Yi Fan
Publisher: Open Dissertation Press
ISBN: 9781374664661
Category :
Languages : en
Pages :
Get Book Here
Book Description
This dissertation, "Ecoepidemiology of Laribacter Hongkongensis, a Novel Bacterium Associated With Community-acquired Gastroenteritis" by Yuen-yi, Fan, 范婉儀, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled "Ecoepidemiology of Laribacter hongkongensis, a Novel Bacterium Associated with Community-acquired Gastroenteritis" Submitted by Fan Yuen Yi for the degree of Master of Philosophy at the University of Hong Kong in August 2006 Laribacter hongkongensis, a recently discovered bacterium associated with community-acquired gastroenteritis, has been found in the intestines of freshwater fish. To better understand the epidemiology and ecology of the bacterium, a surveillance study was carried out to investigate seasonal variation in the recovery of L. hongkongensis in retail freshwater fish intestines in Hong Kong. In this study, intestines from 120 grass carps were sampled during a one-year period. L. hongkongensis was isolated from 49 (41%) of 120 grass carps. Seasonal variation in the recovery of L. hongkongensis was observed, with higher isolation rates in spring and summer than in fall and winter. There was also positive correlation between ambient temperature and the isolation rates. When L. hongkongensis was cultured in vitro at different temperatures, shorter lag time and higher growth rate were observed at higher temperatures, with 37C being optimal among the tested temperatures. Although freshwater fish has been found to be the reservoir of L. hongkongensis, little is known about its survival in aquatic environment. To investigate the presence of L. hongkongensis in fresh water environments, a one-year surveillance study was carried out in ten drinking water reservoirs in Hong Kong. L. hongkongensis was isolated from six of the ten reservoirs, including Pok Fu Lam reservoir, Tai Tam reservoir, Aberdeen reservoir, Kowloon reservoir, Shek Lei Pui reservoir and Shek Pik reservoir. Again, seasonal variation was observed, with higher recovery rates in summer and during days with higher water and ambient temperatures. Of 27 freshwater fish collected from six reservoirs, L. hongkongensis was recovered from two fish collected from two reservoirs. Overall, 35 different pulsed-field gel electrophoresis patterns, different from those previous isolates from human and freshwater fish from retail food markets, are found among the total of 61 isolates. Isolates of L. hongkongensis were shown to grow in autoclaved water samples collected from reservoir, supporting that the bacterium can survive in water environments free of freshwater fish. This is the first study to demonstrate the presence of L. hongkongensis in natural water environments. ------Total word count: 333------ 2 DOI: 10.5353/th_b3734418 Subjects: Neisseriaceae - Ecology - China - Hong Kong Gastroenteritis Laribacter hongkongensis
Author: Lee-Lee Jade Teng
Publisher: Open Dissertation Press
ISBN: 9781361208045
Category :
Languages : en
Pages :
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Book Description
This dissertation, "Laribacter Hongkongensis: Novel Bacterium Associated With Gastroenteritis" by Lee-lee, Jade, Teng, 鄧莉莉, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled "Laribacter hongkongensis, a novel bacterium associated with gastroenteritis" Submitted by Teng Lee Lee for the degree of Doctor of Philosophy at The University of Hong Kong in September 2005 In the first part of the study, a novel bacterium was isolated from the blood culture and empyema in a cirrhotic patient. The cells were facultative anaerobic, non-sporulating, Gram negative, spiral shaped rods. It grows on sheep blood agar as non-hemolytic, gray colonies of 1 mm in diameter after 24 hours of incubation at 37C in ambient air. Growth also occurs on MacConkey agar, at 25C and 42C and in 1% and 2% NaCl. This strain is aflagellated and non-motile. It is oxidase, catalase, urease, and arginine dihydrolase positive, and it reduces nitrate to nitrite but does not reduce nitrite. It does not ferment, oxidize, or assimilate any sugar tested. 16S ribosomal RNA gene sequencing showed that there were 6.2% difference between the bacterium and Microvirgula aerodenitrificans. The G + C content of it (mean SD) was 68.0 2.43%. Its genomic size was about 3 Mb. It belongs to the Neisseriaceae family of the β-subclass of Proteobacteria. This bacterium was named Laribacter hongkongensis gen. nov., sp. nov. In the second part of the study, L. hongkongensis was isolated in pure culture on 2 charcoal cefoperazone deoxycholate agar from the stool of six patients with diarrhea. Unlike L. hongkongensis type strain HKU1, all the six strains were motile with bipolar flagellae. Sequencing of the 16S ribosomal RNA genes showed that they all had sequences with only 0-2 base differences to that of the type strain. Pulsed-field gel electrophoresis of the SpeI digested genomic DNA of the six isolates and that of the type strain revealed that the seven isolates were genotypically unrelated strains. In the third part of the study, a new selective medium, cefoperazone MacConkey agar containing 32 μg/ml cefoperazone, was developed for primary isolation of L. hongkongensis from stool. The performance of this medium on the quantitative recovery of L. hongkongensis and suppression of standard aerobic enteric bacteria was superior to charcoal cefoperazone deoxycholate agar. In the fourth part of the study, a prospective study to determine the association of L. hongkongensis with gastroenteritis, the associated risk factors and the source of L. hongkongensis was carried out. During a four-month period, L. hongkongensis was recovered from 17 out of 3788 patients with community-acquired gastroenteritis, but none of 1894 controls (PIn the last part of my study, a territory-wide eco-epidemiology study was carried out. In this surveillance study, L. hongkongensis was isolated solely from freshwater 3 fish (60% grass carps, 53% bighead carps and 25% mud carps). Comparing the pulsed-field gel electrophoresis patterns of fish and patient isolates revealed that most patient isolates were clustered together, suggesting that some clones could be more virulen
Author: Dongyou Liu
Publisher: CRC Press
ISBN: 1439812381
Category : Medical
Languages : en
Pages : 1282
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Book Description
As more original molecular protocols and subsequent modifications are described in the literature, it has become difficult for those not directly involved in the development of these protocols to know which are most appropriate to adopt for accurate identification of bacterial pathogens. Molecular Detection of Human Bacterial Pathogens addresses this issue, with international scientists in respective bacterial pathogen research and diagnosis providing expert summaries on current diagnostic approaches for major human bacterial pathogens. Each chapter consists of a brief review on the classification, epidemiology, clinical features, and diagnosis of an important pathogenic bacterial genus, an outline of clinical sample collection and preparation procedures, a selection of representative stepwise molecular protocols, and a discussion on further research requirements relating to improved diagnosis. This book represents a reliable and convenient reference on molecular detection and identification of major human bacterial pathogens; an indispensable tool for upcoming and experienced medical, veterinary, and industrial laboratory scientists engaged in bacterial characterization; and an essential textbook for undergraduate and graduate students in microbiology.
Author: Yi-Wei Tang
Publisher: Springer
ISBN: 3319951114
Category : Medical
Languages : en
Pages : 760
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Book Description
In recent years, advanced molecular techniques in diagnostic microbiology have been revolutionizing the practice of clinical microbiology in the hospital setting. Molecular diagnostic testing in general and nucleic acid-based amplification methods in particular have been heralded as diagnostic tools for the new millennium. This third edition covers not only the most recent updates and advances, but details newly invented omic techniques, such as next generation sequencing. It is divided into two distinct volumes, with Volume 1 describing the techniques, and Volume 2 addressing their applications in the field. In addition, both volumes focus more so on the clinical relevance of the test results generated by these techniques than previous editions.
Author:
Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 902
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Author: Yi-Wei Tang
Publisher: Springer Science & Business Media
ISBN: 0387328920
Category : Medical
Languages : en
Pages : 550
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Book Description
Clinical microbiologists are engaged in the field of diagnostic microbiology to determine whether pathogenic microorganisms are present in clinical specimens collected from patients with suspected infections. If microorganisms are found, these are identified and susceptibility profiles, when indicated, are determined. During the past two decades, technical advances in the field of diagnostic microbiology have made constant and enormous progress in various areas, including bacteriology, mycology, mycobacteriology, parasitology, and virology. The diagnostic capabilities of modern clinical microbiology laboratories have improved rapidly and have expanded greatly due to a technological revolution in molecular aspects of microbiology and immunology. In particular, rapid techniques for nucleic acid amplification and characterization combined with automation and user-friendly software have significantly broadened the diagnostic arsenal for the clinical microbiologist. The conventional diagnostic model for clinical microbiology has been labor-intensive and frequently required days to weeks before test results were available. Moreover, due to the complexity and length of such testing, this service was usually directed at the hospitalized patient population. The physical structure of laboratories, staffing patterns, workflow, and turnaround time all have been influenced profoundly by these technical advances. Such changes will undoubtedly continue and lead the field of diagnostic microbiology inevitably to a truly modern discipline. Advanced Techniques in Diagnostic Microbiology provides a comprehensive and up-to-date description of advanced methods that have evolved for the diagnosis of infectious diseases in the routine clinical microbiology laboratory. The book is divided into two sections. The first techniques section covers the principles and characteristics of techniques ranging from rapid antigen testing, to advanced antibody detection, to in vitro nucleic acid amplification techniques, and to nucleic acid microarray and mass spectrometry. Sufficient space is assigned to cover different nucleic acid amplification formats that are currently being used widely in the diagnostic microbiology field. Within each technique, examples are given regarding its application in the diagnostic field. Commercial product information, if available, is introduced with commentary in each chapter. If several test formats are available for a technique, objective comparisons are given to illustrate the contrasts of their advantages and disadvantages. The second applications section provides practical examples of application of these advanced techniques in several "hot" spots in the diagnostic field. A diverse team of authors presents authoritative and comprehensive information on sequence-based bacterial identification, blood and blood product screening, molecular diagnosis of sexually transmitted diseases, advances in mycobacterial diagnosis, novel and rapid emerging microorganism detection and genotyping, and future directions in the diagnostic microbiology field. We hope our readers like this technique-based approach and your feedback is highly appreciated. We want to thank the authors who devoted their time and efforts to produce their chapters. We also thank the staff at Springer Press, especially Melissa Ramondetta, who initiated the whole project. Finally, we greatly appreciate the constant encouragement of our family members through this long effort. Without their unwavering faith and full support, we would never have had the courage to commence this project.
