1,721,133 research outputs found
Bacterial methionine aminopeptidase as a potential target for therapeutics
No full textpublished_or_final_versionabstractMicrobiologyMasterMaster of Philosoph
Antimicrobial resistance in Escherichia coli isolated from food animals and humans
No full textpublished_or_final_versionabstractMicrobiologyMasterMaster of Philosoph
Extended-spectrum beta-lactamases in fecal isolates of Escherichia coli from human and food animals
No full textpublished_or_final_versionabstractMicrobiologyMasterMaster of Philosoph
Reducing bacterial resistance with IMPACT: Interhospital multi-disciplinary programme on antimicrobial chemotherapy
No full textMolecular epidemiology of fluoroquinolones-resistant mycobacterium tuberculosis by MIRU-VNTR gentoyping
No full textAbstract of thesis entitled “Molecular Epidemiology of Fluoroquinolones-resistant Mycobacterium tuberculosis by MIRU-VNTR Genotyping”
Submitted by Yuen Suk Han
for the degree of Master of Philosophy
at The University of Hong Kong in October 2019
Multidrug-resistant tuberculosis (MDR-TB) is an essential global public health concern. Fluoroquinolones and second-line injectable drugs are used in MDR-TB treatment. In general, the laboratory results for diagnosis of tuberculosis (TB) and phenotypic drug susceptibility testing are available in few months. Besides, gyrase mutation in Mycobacterium tuberculosis (MTB) could not account for all fluoroquinolones resistance. Other fluoroquinolones-resistant (FLQs-R) mechanisms in MTB genome such as efflux pump and MfpA PRP expression, which has been associated with the elevation of fluoroquinolones minimum inhibition concentration and reported in Mycobacterium strains other than MTB. Moreover, the epidemiology of FLQs-R MTB in Hong Kong remains unknown.
This study aims at the correlation of FLQs-R isolates with their genotypic mutations and the molecular epidemiology of FLQs-R isolates was investigated using Mycobacterial Interspersed Repetitive Units-Variable Number Tandem Repeat (MIRU-VNTR) typing.
A total of 73 MTB isolates were tested by DNA Sanger sequencing for the quinolone resistance determining region (QRDR) of the gyrA gene. Among these 73 MTB isolates, 22 FLQs-R isolates with most common mutations were detected in codon 90 (5 out of 22, 22.7%) and codon 94 (15 out of 22, 68%) of QRDR gyrA gene. Novel mutation among FLQs-R MTB was not detected and MDR-TB strains were highly associated with FLQs-resistance (18/22, 81%).
Among 73 clinical isolates of MTB, 71 from 61 non-duplicating TB cases were studied by the 24-loci MIRU-VNTR typing. Analysis revealed 61 isolates were linked with West African lineage I (2 out of 31, 3.3%), Euro-American lineage (3 out of 31, 4.9%), Indo-Oceanic lineage (6 out of 61, 9.8%), and East Asian lineage (48 out of 61, 78.7%) respectively. The predominant East-Asian lineage was associated with pulmonary TB infection and 20 (20 out of 21, 95%) were FLQs-R strains. Among these FLQs-R strains, there were 4 clusters without epidemiological linkage. From each cluster, predominant FLQs-R MTB variant was identified with no statistically significant difference (p>0.05) during time of infection.
In conclusion, understanding the epidemiology of FLQs-R MTB stains can assist to minimize the gap in TB detection and treatment. Early detection facilitates not only patient treatment, but also minimize TB spread from transmission. The phenotypic susceptibility test for fluoroquinolones in MTB can be predicted by genotypic testing, which shortens the time of detection for fluoroquinolones resistance. Most of MDR-TB isolates in this study also acquired fluoroquinolones resistance, the use of fluoroquinolones in MDR-TB treatment should be cautioned.
(word count: 396 words) published_or_final_versionMicrobiologyMasterMaster of Philosoph
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Reducing bacterial resistance with IMPACT-Interhospital Multi-disciplinary Programme on Antimicrobial ChemoTherapy, Fourth Edition
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Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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