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Title: Rapid colorimetric based antimicrobial susceptibility testing :development, evaluation and potential.
Author: Brady, Aaron John
ISNI:       0000 0001 3476 3610
Awarding Body: Queen's University of Belfast
Current Institution: Queen's University Belfast
Date of Award: 2008
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Rapid and reliable antimicrobial susceptibility testing plays a vital role in deciding the appropriate antibiotic therapy prescribed. Current techniques employed by clinical laboratories include breakpoint tests and microdilution assays which typically provide susceptibility data after 18 to 24 hours. The primary aim of this study was to develop a reliable antimicrobial susceptibility test, using a tetrazolium-based salt as a colorimetric indicator ofbacterial metabolism, which could provide accurate susceptibility data within 4 to 5 hours. Using clinical isolates from several bacterial species this study found that the tetrazolium salt, XTI, provided rapid and reliable susceptibility data when compared with conventional broth microdilution testing. In addition to providing accurate susceptibility data in 4 hours this study also revealed that XTI was more accurate and reliable than the newer and more expensive tetrazolium salt, WST-8. Biofilm formation is recognised as an important virulence factor for infections associated with indwelling devices and implants. Treatment of biofilm associated infection frequently requires high dose antibiotic therapy and often necessitates removal of the implanted device. This study found that irrespective ofthe site from which the isolate was cultured, bacteria growing in biofilm displayed a common trait of greatly increased resistance to antibiotic therapy. The present study also showed that tea-tree oil (TID) has considerable potential as an antimicrobial agent against biofilm grown isolates. Furthermore, it has also shown that TID is more active against bacteria such as meticillin-resistant staphylococcus aureus (MRSA), which are transiently found on the skin, than coagulase-negative staphylococci, which are part of the resident skin flora. The results presented in this study demonstrate that the use of a colorimetric assay for MIC determination is a viable alternative to current overnight assays while highlighting the potential that alternative agents such as TID may have in combating biofilm-related infection. Supplied by The British Library - 'The world's knowledge'
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available