Postgraduate
BSc (Hons)
| Contact Campus | Newnham Campus |
| Building | Building C |
| Room Reference | N203 |
| Telephone | +61 3 6324 3619 |
| E.A.Witherden@utas.edu.au |
My research interests are in the area of microbiology, in particular antibiotic resistance mechanisms in Haemophilus influenzae, a common aetiological agent in respiratory tract infections. I am currently undertaking my PhD under the supervision of Dr. Stephen Tristram and Dr. Murray Adams, and have many Australian and International collaborators. Most recently, presenting at the 22nd Annual European Congress of Clinical Microbiology and Infectious Diseases in London UK, and working in Lisbon Portugal with Dr. Paula Lavado from the National Health Institute of Infectious Diseases, Doutor Ricardo Jorge analyzing the genetic relatedness of Haemophilus influenzae strains isolated from pediatric patients in Perth, Australia.
Dr. Stephen Tristram
Dr. Murray Adams
The most common illnesses for which antibiotics are prescribed in Australia are upper respiratory tract infections, and these are frequently caused by Haemophilus influenzae. The most commonly prescribed antibiotics in these situations are amoxicillin, amoxicillin/clavulanate and cefaclor, to which H. influenzae is becoming increasingly resistant due to an emerging resistance mechanism. Recent studies show that approximately 10% of Australian strains of H. influenzae have this resistance, although in most strains the resistance goes undetected.
Although the molecular basis for this resistance is known to be various specific and often multiple amino acid substitutions in the penicillin binding protein target site, little is known about the relative contributions of the substitutions to the different levels of antibiotic resistance seen in clinical isolates. Similarly, little is known about the sequence in which these substitutions evolve, whether the closely related Haemophilus haemolyticus is a silent reservoir for these substitutions, or the ability of different antibiotics to select for the emergence of the resistance.
The AIM of this research is to use site directed mutagenesis and cloning techniques to construct a library of strains with various combinations of amino acid substitutions. This library will then be used to determine the relative roles of specific single and multiple substitutions on the level of antibiotic resistance, and the ability of various antibiotics to select for increased resistance and or increased substitutions from various parent strains.
The expected OUTCOME of the research will be an increased understanding of the genetic basis and evolution of this important resistance mechanism that might then be applied to better laboratory detection and clinical management.
PFGE Image depicting the genetic relatedness of some clinical isolates of Haemophilus influenzae.