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- Creators: Barrett, The Honors College
- Creators: Kavazanjian, Edward
- Creators: Allenby, Braden
- Creators: Cadillo – Quiroz, Hinsby
Description
The purpose of this study was to observe the effectiveness of the phenylalanyl arginine β-naphthylamide dihydrochloride inhibitor and Tween 20 when combined with an antibiotic against Escherichia. coli. As antibiotic resistance becomes more and more prevalent it is necessary to think outside the box and do more than just increase the dosage of currently prescribed antibiotics. This study attempted to combat two forms of antibiotic resistance. The first is the AcrAB efflux pump which is able to pump antibiotics out of the cell. The second is the biofilms that E. coli can form. By using an inhibitor, the pump should be unable to rid itself of an antibiotic. On the other hand, using Tween allows for biofilm formation to either be disrupted or for the biofilm to be dissolved. By combining these two chemicals with an antibiotic that the efflux pump is known to expel, low concentrations of each chemical should result in an equivalent or greater effect on bacteria compared to any one chemical in higher concentrations. To test this hypothesis a 96 well plate BEC screen test was performed. A range of antibiotics were used at various concentrations and with varying concentrations of both Tween and the inhibitor to find a starting point. Following this, Erythromycin and Ciprofloxacin were picked as the best candidates and the optimum range of the antibiotic, Tween, and inhibitor were established. Finally, all three chemicals were combined to observe the effects they had together as opposed to individually or paired together. From the results of this experiment several conclusions were made. First, the inhibitor did in fact increase the effectiveness of the antibiotic as less antibiotic was needed if the inhibitor was present. Second, Tween showed an ability to prevent recovery in the MBEC reading, showing that it has the ability to disrupt or dissolve biofilms. However, Tween also showed a noticeable decrease in effectiveness in the overall treatment. This negative interaction was unable to be compensated for when using the inhibitor and so the hypothesis was proven false as combining the three chemicals led to a less effective treatment method.
ContributorsPetrovich Flynn, Chandler James (Author) / Misra, Rajeev (Thesis director) / Bean, Heather (Committee member) / Perkins, Kim (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Antibiotics, bacteria, and the continuing trend of antibiotic resistance increasing in various bacteria strains is a complex and multifaceted set of relationships explored in this thesis. Examining a variety of published literature in various sectors of influence, including the social, medical, and economic divisions, this thesis examined the core factors and combined them into a set of recommendations for future progress. In this way, the subject of antibiotic resistance in bacteria begins with an evaluation of the history then continued into an analysis of the economic factors, a social understanding of the subject, a medical evaluation of current procedure, and a concluding framework and general set of recommendations for future use. Ultimately, these factors require a multifaceted approach in order to combat the numerous factors and contributions to emerging antibiotic resistance in bacteria both in the United States of America and around the world.
ContributorsMurphy, Emily Ann (Author) / Chhetri, Netra (Thesis director) / Ankeny, Casey (Committee member) / Hamburg, Robert (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
The diagnosis of bacterial infections based on phage multiplication has the potential for profound clinical implications, particularly for antibiotic-resistant strains and the slow-growing Mycobacterium tuberculosis. The possibility of hastening the diagnosis of antibiotic-resistant mycobacterial infections was accomplished via the study of Mycobacterium smegmatis, a generally non-pathogenic, comparatively fast growing microorganism to M. tuberculosis. These proof-of-concept studies established that after transduction of M. smegmatis cells with bacteriophages, MALDI-TOF MS could be used to detect increased amounts of phage proteins. Recording the growth of M. smegmatis over an 8-hour period, starting with very low OD600 measurements, simulated bacterial loads in clinical settings. For the purposes of MALDI-TOF MS, the procedure for the most effective lethal exposure for M. smegmatis was determined to be a 1-hour incubation in a 95°C water bath. Successful precipitation of the lytic mycobacteriophages D29 and Giles was performed using chloroform and methanol and overlaid with 1-2 μL of α-cyano-4-hydoxycinnaminic acid, which allowed for more distinct and repeatable MALDI-TOF MS spectra. Phage D29 was found to produce an m/z peak at 18.477 kDa, which may have indicated a 2+-charged ion of the 34.8 kDa minor tail protein. The Giles proteins that were identified with MALDI-TOF MS have not been directly compared to protein values reported in the scientific literature. However, the MALDI-TOF MS spectra suggested that distinct peaks existed between M. smegmatis mc2155 and mycobacteriophages, indicating that successful infection with lytic phage and replication thereafter may have occurred. The distinct peaks between M. smegmatis and the phage can be used as indicators of the presence of mycobacteria. At this point, the limits of detection of each phage must be elucidated in order for MALDI-TOF MS spectra to be successfully implemented as a mechanism to rapidly detect antibiotic-resistant mycobacteria.
ContributorsBarrett, Rachael Lauren (Author) / Haydel, Shelley (Thesis director) / Sandrin, Todd (Committee member) / Maarsingh, Jason (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
Currently conventional Subtitle D landfills are the primary means of disposing of our waste in the United States. While this method of waste disposal aims at protecting the environment, it does so through the use of liners and caps that effectively freeze the breakdown of waste. Because this method can keep landfills active, and thus a potential groundwater threat for over a hundred years, I take an in depth look at the ability of bioreactor landfills to quickly stabilize waste. In the thesis I detail the current state of bioreactor landfill technologies, assessing the pros and cons of anaerobic and aerobic bioreactor technologies. Finally, with an industrial perspective, I conclude that moving on to bioreactor landfills as an alternative isn't as simple as it may first appear, and that it is a contextually specific solution that must be further refined before replacing current landfills.
ContributorsWhitten, George Avery (Author) / Kavazanjian, Edward (Thesis director) / Allenby, Braden (Committee member) / Houston, Sandra (Committee member) / Civil, Environmental and Sustainable Engineering Programs (Contributor) / Barrett, The Honors College (Contributor)
Created2013-05
Description
Antibiotic resistance in the modern era has reached near-epidemic levels, resulting in much more difficult treatment of previously well-managed pathogens. Previous understandings of how antibiotic resistance emerges failed to account for the function of the environment. Over the past 15 years, new research has provided a link between the environmental and clinical spheres of antibiotic use. This data suggests that environmental bacteria, particularly those found in livestock farming ecosystems, may significantly contribute to the overall flow of antibiotic resistance genes into human populations. The main force behind this is the utilization of antibiotics as growth promoters in animal feed supplements, seeding individual animals and their surroundings with low doses of antibiotics. Notable increases in resistance have been observed within areas that utilize these supplements, as well as in connected but unrelated systems. Waste management strategies are poorly implemented, leading to the dispersal of contaminated runoff into groundwater and riverine environments. Furthermore, existing waste processing is limited in efficacy, often releasing large amounts of unprocessed antibiotics as well as a concentrated population of resistant bacteria. Within these resistant populations, horizontal gene transfer has emerged as a vehicle for the distribution of resistance genes into other populations of bacteria. Due to the prevalence of these transfer events, a new role for the environment as a reservoir and incubator of resistance genes is proposed. Current strategies for managing the spread of antibiotic resistance are woefully inadequate, and the continued emergence of new resistance mechanisms due to negligence highlights the need for global, multidisciplinary solutions. To corral the spread of antibiotic resistance, a system is proposed that utilizes metagenomic monitoring and the enforcement of core global policies to slow the advance of resistance while waiting for novel treatment strategies to bear fruit.
ContributorsHrkal, Jacob (Author) / Gile, Gillian (Thesis director) / Shi, Yixin (Committee member) / Sarno, Analissa (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Managed Aquifer Recharge is an increasingly prevalent solution to sustain water availability in arid regions. Recharge of groundwater resources using treated wastewater effluent is one type of managed aquifer recharge that offers long-term sustainable water management. However, there are some concerns regarding the reuse of wastewater and its potential to increase exposures to antibiotic resistant bacteria and antibiotic resistance genes that could affect human health. Antibiotic resistance genes can confer the ability for bacteria to resist antibacterial treatment, rendering their presence in water supplies as an area of research needed to evaluate where environmental “hot spots” of potential antibiotic resistance disseminate. To evaluate the occurrence of antibiotic resistant bacteria and antibiotic resistance genes, sampling of an Arizona managed aquifer recharge facility was performed, with target antibiotic resistance genes measured using quantitative polymerase chain reaction. The occurrence of antibiotic resistance genes was evaluated at several sampling wells and in sediments to examine trade-offs between water quantity benefits and water quality issues. The goal of this work is to inform management operations for secure water quality in the face of climate change.
ContributorsDieter, Lucien Andres (Author) / Hamilton, Kerry A. (Thesis director) / Shrestha, Milan (Committee member) / Environmental and Resource Management (Contributor, Contributor) / School of Music, Dance and Theatre (Contributor) / School of Sustainability (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
Bacteriophages are the most numerous type of organisms in the world. These viruses have the ability to destroy bacteria that they specifically match. Phage therapy shows great promise to become a solution to bacterial infections and antibiotic resistance. To ensure that younger generations are aware of this field of research, we created a website to educate them. The website contains lessons and a game that will encourage confidence, curiosity, and understanding of bacteriophages.
ContributorsKowal, Maria (Author) / Pfiefer, Susanne (Thesis director) / Versoza, Cyril (Committee member) / Milhaven, Mark (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor) / Edson College of Nursing and Health Innovation (Contributor)
Created2023-05
Characterization and Manipulation of Microbiomes From Arid Landfills for Improved Methane Production
Description
Environmentally harmful byproducts from solid waste’s decomposition, including methane (CH4) emissions, are managed through standardized landfill engineering and gas-capture mechanisms. Yet only a limited number of studies have analyzed the development and composition of Bacteria and Archaea involved in CH4 production from landfills. The objectives of this research were to compare microbiomes and bioactivity from CH4-producing communities in contrasting spatial areas of arid landfills and to tests a new technology to biostimulate CH4 production (methanogenesis) from solid waste under dynamic environmental conditions controlled in the laboratory. My hypothesis was that the diversity and abundance of methanogenic Archaea in municipal solid waste (MSW), or its leachate, play an important role on CH4 production partially attributed to the group’s wide hydrogen (H2) consumption capabilities. I tested this hypothesis by conducting complementary field observations and laboratory experiments. I describe niches of methanogenic Archaea in MSW leachate across defined areas within a single landfill, while demonstrating functional H2-dependent activity. To alleviate limited H2 bioavailability encountered in-situ, I present biostimulant feasibility and proof-of-concepts studies through the amendment of zero valent metals (ZVMs). My results demonstrate that older-aged MSW was minimally biostimulated for greater CH4 production relative to a control when exposed to iron (Fe0) or manganese (Mn0), due to highly discernable traits of soluble carbon, nitrogen, and unidentified fluorophores found in water extracts between young and old aged, starting MSW. Acetate and inhibitory H2 partial pressures accumulated in microcosms containing old-aged MSW. In a final experiment, repeated amendments of ZVMs to MSW in a 600 day mesocosm experiment mediated significantly higher CH4 concentrations and yields during the first of three ZVM injections. Fe0 and Mn0 experimental treatments at mesocosm-scale also highlighted accelerated development of seemingly important, but elusive Archaea including Methanobacteriaceae, a methane-producing family that is found in diverse environments. Also, prokaryotic classes including Candidatus Bathyarchaeota, an uncultured group commonly found in carbon-rich ecosystems, and Clostridia; All three taxa I identified as highly predictive in the time-dependent progression of MSW decomposition. Altogether, my experiments demonstrate the importance of H2 bioavailability on CH4 production and the consistent development of Methanobacteriaceae in productive MSW microbiomes.
ContributorsReynolds, Mark Christian (Author) / Cadillo-Quiroz, Hinsby (Thesis advisor) / Krajmalnik-Brown, Rosa (Thesis advisor) / Wang, Xuan (Committee member) / Kavazanjian, Edward (Committee member) / Arizona State University (Publisher)
Created2022
Description
Zero-Valent Metals (ZVM) are highly reactive materials and have been proved to be effective in contaminant reduction in soils and groundwater remediation. In fact, zero-Valent Iron (ZVI) has proven to be very effective in removing, particularly chlorinated organics, heavy metals, and odorous sulfides. Addition of ZVI has also been proved in enhancing the methane gas generation in anaerobic digestion of activated sludge. However, no studies have been conducted regarding the effect of ZVM stimulation to Municipal Solid Waste (MSW) degradation. Therefore, a collaborative study was developed to manipulate microbial activity in the landfill bioreactors to favor methane production by adding ZVMs. This study focuses on evaluating the effects of added ZVM on the leachate generated from replicated lab scale landfill bioreactors. The specific objective was to investigate the effects of ZVMs addition on the organic and inorganic pollutants in leachate. The hypothesis here evaluated was that adding ZVM including ZVI and Zero Valent Manganese (ZVMn) will enhance the removal rates of the organic pollutants present in the leachate, likely by a putative higher rate of microbial metabolism. Test with six (4.23 gallons) bioreactors assembled with MSW collected from the Salt River Landfill and Southwest Regional Landfill showed that under 5 grams /liter of ZVI and 0.625 grams/liter of ZVMn additions, no significant difference was observed in the pH and temperature data of the leachate generated from these reactors. The conductivity data suggested the steady rise across all reactors over the period of time. The removal efficiency of sCOD was highest (27.112 mg/lit/day) for the reactors added with ZVMn at the end of 150 days for bottom layer, however the removal rate was highest (16.955 mg/lit/day) for ZVI after the end of 150 days of the middle layer. Similar trends in the results was observed in TC analysis. HPLC study indicated the dominance of the concentration of heptanoate and isovalerate were leachate generated from the bottom layer across all reactors. Heptanoate continued to dominate in the ZVMn added leachate even after middle layer injection. IC analysis concluded the chloride was dominant in the leachate generated from all the reactors and there was a steady increase in the chloride content over the period of time. Along with chloride, fluoride, bromide, nitrate, nitrite, phosphate and sulfate were also detected in considerable concentrations. In the summary, the addition of the zero valent metals has proved to be efficient in removal of the organics present in the leachate.
ContributorsPandit, Gandhar Abhay (Author) / Cadillo – Quiroz, Hinsby (Thesis advisor) / Olson, Larry (Thesis advisor) / Boyer, Treavor (Committee member) / Arizona State University (Publisher)
Created2019
Description
Each year, more and more multi-drug resistant bacterial strains emerge, thus complicating treatment and increasing the average stay in the intensive care unit. As antibiotics are being rendered inefficient, there is a need to look into ways of weakening the internal state of bacterial cells to make them more susceptible to antibiotics. For this, we first need to understand what methods bacteria employ to fight against antibiotics. In this work, we have reviewed how bacteria respond to antibiotics. There is a similarity in response to antibiotic exposure and starvation (stringent stress) which changes the metabolic state. We have delineated what metabolism changes take place and how they are associated with oxidative stress. For example, there is a common change in NADH concentration that is tied to both metabolism and oxidative stress. Finally, we have compared the findings in literature with our research on an antibiotic-resistant RNA polymerase mutant that alters the gene expression profile in the general areas of metabolism and oxidative stress. Based on this thesis, we have suggested a couple of strategies to make antibiotics more efficient; however, as antibiotic-mediated killing is very complex, researchers need to delve deeper to understand and manipulate the full cellular response.
ContributorsPredtechenskaya, Maria (Author) / Misra, Rajeev (Thesis director) / Varman, Arul Mozhy (Committee member) / Mhatre, Apurv (Committee member) / Computer Science and Engineering Program (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05