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Full-Text Articles in Microbiology

Periodic Spatial Disturbances Alter The Expression Of Quorum Sensing Virulence Factors In Pseudomonas Aeruginosa, Laura García-Diéguez Apr 2022

Periodic Spatial Disturbances Alter The Expression Of Quorum Sensing Virulence Factors In Pseudomonas Aeruginosa, Laura García-Diéguez

All HCAS Student Capstones, Theses, and Dissertations

Pseudomonas aeruginosa is an opportunistic pathogen associated with severe acute and chronic illnesses. Current antibiotic-based approaches fail to effectively treat P. aeruginosa infections due to the effectiveness and robustness of the quorum sensing signaling system (QS). Pathogenic bacteria, such as P. aeruginosa, employ this population density-dependent communication mechanism to confer antimicrobial resistance, propagate infection, and coordinate the expression of virulence factors, through the production and detection of autoinducing signaling molecules (AI). As such, there is a growing interest in developing novel non-antibiotic-based techniques to attenuate the pathogenicity of P. aeruginosa by disrupting the functionality of its QS system. Previous …


Increasing The Frequency Of Periodic Spatial Disturbance Decreases Surface Attachment Protein Expression In Staphylococcus Aureus, Ivana M. Barraza Apr 2021

Increasing The Frequency Of Periodic Spatial Disturbance Decreases Surface Attachment Protein Expression In Staphylococcus Aureus, Ivana M. Barraza

All HCAS Student Capstones, Theses, and Dissertations

Staphylococcus aureus is an opportunistic pathogen that can cause a variety of acute and chronic illnesses. The severity of these illnesses such as sepsis, necrotizing pneumonia, and toxic shock syndrome is measured through the virulence that S. aureus inflicts on its host. Methicillin-resistant S. aureus (MRSA) is commonly associated with secondary infections and is challenging to treat given the limited selection of antibiotics that are effective against it. Accordingly, novel approaches to reduce S. aureus pathogenicity are required. S. aureus regulates pathogenesis through a cell-to-cell communication system referred to as quorum sensing. Effective communication determines the production of two broad …


Transposon Mutagenesis Facilitates Discovery Of Genotype-Phenotype Associations And Functional Interrogation Of The Mycobacterium Kansasii Genome, William C. Budell Sep 2019

Transposon Mutagenesis Facilitates Discovery Of Genotype-Phenotype Associations And Functional Interrogation Of The Mycobacterium Kansasii Genome, William C. Budell

Dissertations, Theses, and Capstone Projects

Mycobacterium kansasii (Mk) is a nontuberculous mycobacterium (NTM) and medically relevant opportunistic human pathogen. Mk causes dangerous disease pathologies ranging from tuberculosis-like chronic pulmonary disease (CPD) to non-pulmonary focal or disseminated infections that are exacerbated by comorbidities such as chronic obstructive pulmonary disease (COPD), co-infection with HIV, or cancer. Among the most frequently identified cause of NTM-linked CPD, Mk infections contribute to a globally increasing NTM disease burden and are difficult to treat, requiring a long-term, multi-drug regimen. Although a less virulent pathogen than Mycobacterium tuberculosis (Mtb), Mk elicits similar disease features and shares in vitro …


Relationships Between Factors Influencing Biofilm Formation And Pathogen Retention In Complex Rhizosphere Microbial Communities, Aaron Coristine Jan 2018

Relationships Between Factors Influencing Biofilm Formation And Pathogen Retention In Complex Rhizosphere Microbial Communities, Aaron Coristine

Theses and Dissertations (Comprehensive)

Riparian wetlands are unique habitats facilitating all forms of life. The riverbanks of these environments provide ideal conditions for bacteria, plants, and higher organisms. Of particular interest to this research was the variation in microbial community structure at high, intermediate and poor water quality impacted areas. Assessing the capabilities of plants to retain microbial pathogens was identified. Root systems and corresponding soil are ideal locations for bacterial deposition, resulting in attachment at these areas. Biofilm production in these regions is important for long-term establishment, leading to persistence and potential naturalization. Opportunistic pathogens originating from mammalian fecal matter are introduced into …


Determination Of The Effects That A Previously Uncharacterized Secreted Product From Klebsiella Pneumoniae Has On Citrobacter Freundii And Enterobacter Cloacae Biofilms, Cody M. Hastings May 2017

Determination Of The Effects That A Previously Uncharacterized Secreted Product From Klebsiella Pneumoniae Has On Citrobacter Freundii And Enterobacter Cloacae Biofilms, Cody M. Hastings

Undergraduate Honors Theses

More so than ever, Multiple Drug Resistant (MDR) bacteria are on the rise due to overuse of antibiotics along with natural selection for adaptations that enhance drug-resistant properties. One particular bacterial family, Enterobacteriaceae, has been problematic, exhibiting several bacterial members that have developed a precipitous resistance to modern antibiotics and are also primary causative agents of nosocomial, or hospital acquired, infections. Citrobacter freundii (CF) and Enterobacter cloacae (ECL) are two species of the Enterobacteriaceae family causing significant medical concern due to their role in producing numerous opportunistic infections such as bacteremia, lower respiratory tract infections, urinary tract infections, and endocarditis. …


Analysis Of The Prevention Of Biocorrosion Caused By Desulfovibrio Alaskensis G20, Michael Boring Jan 2017

Analysis Of The Prevention Of Biocorrosion Caused By Desulfovibrio Alaskensis G20, Michael Boring

Honors Undergraduate Theses

Desulfovibrio alaskensis G20 and other sulfate-reducing bacteria cause significant damage to metal pipelines and other infrastructure through a metabolic pathway that releases toxic hydrogen sulfide into their surroundings. The biocorrosion that results from the release of hydrogen sulfide creates significant economic burden, and can pose health risks for those exposed to this chemical. They are commonly present in the form of biofilms, an extracellular matrix composed of bacterial cells, polysaccharides, proteins, nucleic acids, and other materials. These biofilms are difficult to remove, and they provide protection to the bacteria within from anti-bacterial treatments. Desulfovibrio alaskensis G20 is a strain derived …


Biosynthesis And Roles Of Virulence Conferring Cell Wall Associated Dimycocerosate Esters In Mycobacterium Marinum, Poornima Mohandas Jun 2016

Biosynthesis And Roles Of Virulence Conferring Cell Wall Associated Dimycocerosate Esters In Mycobacterium Marinum, Poornima Mohandas

Dissertations, Theses, and Capstone Projects

Mycobacterial species include a variety of obligate and opportunistic pathogens that cause several important diseases affecting mankind such as tuberculosis and leprosy. The most unique feature of these bacteria is their intricate cell wall that poses a permeability barrier to antibiotics and contributes to their pathogenicity and persistence within the host. The cell wall hosts several complex lipids such as dimycocerosate esters (DIMs), which are found in many clinically relevant pathogenic species of mycobacteria. DIMs have been implicated in the virulence of mycobacteria and play a major role in helping the bacteria evade host immune responses. It is therefore crucial …