Full metadata record
DC FieldValueLanguage
dc.contributorDepartment of Health Technology and Informaticsen_US
dc.creatorChan, Sze-yeung Anthony-
dc.identifier.urihttps://theses.lib.polyu.edu.hk/handle/200/6396-
dc.languageEnglishen_US
dc.publisherHong Kong Polytechnic University-
dc.rightsAll rights reserveden_US
dc.titleCan resistance develop in further vancomycin exposure of previously vancomycin non-susceptible strains which have reverted to susceptible?en_US
dcterms.abstractMRSA is a common pathogen associated with nosocomial and community acquired infections⁽⁹⁾. To treat MRSA, vancomycin remains the drug of choice. Since the first report of VISA/hVISA in Japan in 1997⁽³⁰⁾, the prevalence of reduced vancomycin susceptibility is increasing worldwide. Vancomycin treatment failure has become a problem in medical communities⁽²¹⁾. Vancomycin inhibits cell wall synthesis in Staphylococcus aureus. Cell wall thickening is a major feature of VISA, the thickened cell wall slow down the diffusion of vancomycin molecule to its active site in the cytoplasmic membrane of division septum resulting in decreased potency of the vancomycin. ⁽¹⁸⁾ The two component system, vraSR and graSR, has been associated with glycopeptide resistance in MRSA. Over-expression of vraSR and graSR increases cell wall thickness and raises the vancomycin MIC. Single point mutations in vraSR and graSR genes may contribute to cell wall thickening and loss of vancomycin susceptibility⁽⁶' ⁸' ¹⁴⁾. In this project, six strains of MRSA previously induced to VISA which had reverted to VSSA were exposed to vancomycin again. The MIC trend was monitored and the genetic changes in vraS and graR gene during development and loss of vancomycin non susceptibility were tracked. Results showed that these VSSA strains can be induced to VISA or resistant strain again when re-exposed to vancomycin. Genetic analysis revealed that several mutations caused amino acids change and presence of stop codon in vraS and graR gene during development and loss of vancomycin non susceptibility. All these results suggested that to prevent treatment failure, it is important to monitor the MIC changes during vancomycin therapy.en_US
dcterms.extent81 leaves : ill. ; 30 cm.en_US
dcterms.isPartOfPolyU Electronic Thesesen_US
dcterms.issued2012en_US
dcterms.educationalLevelAll Masteren_US
dcterms.educationalLevelM.Sc.en_US
dcterms.LCSHVancomycin resistance.en_US
dcterms.LCSHStaphylococcus aureus.en_US
dcterms.LCSHMethicillin resistance.en_US
dcterms.LCSHHong Kong Polytechnic University -- Dissertationsen_US
dcterms.accessRightsrestricted accessen_US

Files in This Item:
File Description SizeFormat 
b24713545.pdfFor All Users (off-campus access for PolyU Staff & Students only)1.46 MBAdobe PDFView/Open


Copyright Undertaking

As a bona fide Library user, I declare that:

  1. I will abide by the rules and legal ordinances governing copyright regarding the use of the Database.
  2. I will use the Database for the purpose of my research or private study only and not for circulation or further reproduction or any other purpose.
  3. I agree to indemnify and hold the University harmless from and against any loss, damage, cost, liability or expenses arising from copyright infringement or unauthorized usage.

By downloading any item(s) listed above, you acknowledge that you have read and understood the copyright undertaking as stated above, and agree to be bound by all of its terms.

Show simple item record

Please use this identifier to cite or link to this item: https://theses.lib.polyu.edu.hk/handle/200/6396