As the problem of resistance increases in the current health care system, new
solutions to this problem are not emerging at a similar rate. The ability to discover novel
antibiotics, and modify existing antibiotics, is competing with highly evolving resistance
profiles. An alternate solution to this problem may be to search for inhibitors of these
resistance mechanisms and pairing them with current antibiotics. Proof of this hypothesis
lies in the great success of P-lactamase inhibitors already in the clinic. Inhibitors may be
created using synthetic methods, however searching for inhibitors found in the natural
environment may lead to a greater success. For example, bacteria in their natural setting
must cope with constant exposure to antibiotics secreted by both themselves and by other
species. As well, bacteria must be able to handle encounters with other species that are
resistant to their own defense mechanisms. With this in consideration, it is possible that
these bacteria have already established an ability to challenge resistance encountered in
their own environment, such as through the secretion of compounds that inhibit these
mechanisms. Screening of such inhibitors can be done against purified resistance
elements or via cell-based screens with resistant bacteria. The focus of this research was
to develop expression systems which contain inducible antibiotic resistance genes to be
used for whole-cell screening for inhibitors of antibiotic resistance. The expression
systems studied were pSWEET, for use in the Gram positive bacterium Bacillus subtilis,
and pETcoco, for use in the Gram negative bacterium Escherichia coli. It was found that
the pSWEET expression system integrated into the B. subtilis chromosome at unspecified
locations and was not an ideal system for the proposed screen. pET coco holds promise as a suitable expression system but at this point in time it requires further examination to
ensure plasmid stability and reproducibility of results. Therefore further examination of
these two systems is needed if they are to be used in a screen for inhibitors, and a search
for substitute systems must be undertaken. / Thesis / Master of Science (MSc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/21600 |
| Date | 09 1900 |
| Creators | Sutherland, Arlene |
| Contributors | Wright, G. D., Biblical Studies, Religion |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
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