No description available.

Antibiotic resistant strains of bacteria continue to increase in prevalence, hindering the ability of clinicians to treat infection. One disease exacerbated by this trend is osteomyelitis, or bone infection. When osteomyelitis is induced by these antibiotic resistant strains, patients can experience prolonged hospital visits, greater economic burdens, amputation, and even death. Due to the limitations of antibiotics to clear these infections, we sought to identify new therapeutic options for osteomyelitis. Our aim was to first develop an in vivo implant-related model of osteomyelitis. We then wanted to explore the potential of novel CRISPR-Cas9 modified bacteriophage to treat infection. In vitro and in vivo investigations demonstrated that bacteriophage therapeutic may be a viable option for infection mitigation. Furthermore, our in vivo model of osteomyelitis proved to be reliable, consistent, and challenging. Future research will utilize this model as a platform for optimizing therapeutic regimen and delivery vehicle(s) for antimicrobial therapeutics.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

<p>Bacteria demonstrate an extraordinary capacity to survive and adapt to changing environments. In part, this ability to adapt can be attributed to horizontal gene transfer, a phenomenon which introduces novel genetic information that can be appropriated for use in particular niches. Nowhere is this more relevant than in pathogenic bacteria, whose acquisition of virulence genes have provided an arsenal that permits them to thrive within their selected host. Regulatory evolution is necessary for timely regulation of these acquired virulence genes in the host environment. <em>Salmonella enterica</em> serovar Typhimurium is an intracellular pathogen which possesses numerous horizontally-acquired genomic islands encoding pathogenic determinants that facilitate its host lifestyle. One island, <em>Salmonella</em> Pathogenicity Island (SPI)-2, encodes a type-III secretion system (T3SS) which is regulated by the two-component regulatory system SsrA-SsrB. This system coordinates expression of the SPI-2 T3SS as well as an array of virulence effectors encoded in horizontally-acquired regions throughout the <em>Salmonella</em> genome. The studies presented here investigated the mechanisms in which the transcription factor SsrB functions to integrate virulence processes through regulatory adaptation. This work identified the regulatory logic controlling SsrB and defined the associated SsrB regulon. Furthermore, SsrB was found to induce a regulatory cascade responsible for the expression of bacteriophage genes encoded within SPI-12, an island that also contributes to <em>Salmonella</em> virulence. These findings demonstrate the important contribution of regulatory evolution in pathogen adaptation to the host, and show that horizontally-acquired genes, once integrated into appropriate regulatory networks, can contribute to pathogen fitness in specific niche environments.</p> / Doctor of Philosophy (PhD)

The development of a waterborne pathogen detection method that is rapid, multiplex, sensitive, and specific, would be of great assistance for water treatment facilities and would help protect water consumers from harmful pathogens. Here we have utilized surface enhanced Raman spectroscopy (SERS) in a sensitive multiplex pathogen detection method. Two strategies are proposed herein, one that utilizes SERS antibody labels and one that measures the intrinsic SERS signal of organisms. For the SERS label strategy, gold nanoparticles are conjugated with antibodies specific to Cryptosporidium parvum and Giardia lamblia and with organic dye molecules. The dye molecules, rhodamine B isothiocyanate (RBITC) and malachite green isothiocyanate (MGITC) were surface enhanced by the gold nanoparticles resulting in unique fingerprint SERS spectra. The SERS label method was successful in detecting G. lamblia and C. parvum simultaneously. The method was subsequently coupled with a filtration step to both concentrate and capture cysts on a flat surface for detection. Raman mapping across the filter membrane detected ~95% of the spiked cysts in the optimized system. In the second type of strategy, intrinsic virus SERS signals were detected with silver nanoparticles for enhancement. Principal component analysis performed on the spectra data set resulted in the successful differentiation of MS2 and PhiX174 species and also for the differentiation of viable virus samples and inactivated virus samples. / Ph. D.