Pathogenic Microbiology Commons^™

Dual-Action Antibacterial Agents Targeting Biofilm Reduction And Membrane Disruption In Staphylococcus Aureus, Rahmat Folashade Zakariyah, Waliyullahi Akorede Husain, Elohor Precious Samuel, Wonder Olanipekun Oloruntoba, Fatmah Opeyemi Saka, Khalid Ayinde Oyelami, Mariam Temitope Baker

Al-Bahir

Antimicrobial resistance in Staphylococcus aureus is a serious global health problem as the organism rapidly develops resistance against widely used antibiotics. This study sought to investigate the antibacterial and antibiofilm properties of γ-Tocopherol, a natural compound from Ocimum gratissimum, as well as its synergism with 5-hydroxymethylfurfural (5-HMF) against S. aureus. The antibacterial activities and minimum inhibitory concentrations of the compounds were determined using agar diffusion and microbroth dilution methods, respectively. Biofilm reduction was evaluated using 2,3,5-triphenyltetrazolium chloride (TTC) assay and membrane integrity was evaluated using the crystal violet microtiter plate assay and the ion leakage assay. The results …

Characterization Of Staphylococcus Aureus Clinical Isolates From Deep Musculoskeletal Infections For An In Vitro Biofilm Model For Phage Therapy, Raquel C. Luna

Dissertations and Theses (Open Access)

The rise of multidrug-resistant (MDR) infections is a growing concern in the treatment of deep musculoskeletal infections (MSKIs) and orthopaedic device-related infections (ODRIs). Staphylococcus aureus is responsible for about one third of these infections due to its strong biofilm forming capacity, presence on human skin, and the large number of antibiotic-resistant variants. Bacteriophage (phage) therapy is now being considered as a treatment for MDR MSKIs/ODRIs. We are investigating the use of phage encapsulated into or adsorbed onto biodegradable microspheres for local delivery to the site of these MDR infections. We determined that the anti-staphylococcal phage K effectively lyses the S. …

The Impact Staphylococcus Aureus Has On Conventional And Organic Dairy Herds In New Hampshire And New York, Jacqueline Rose Holmes

Honors Theses and Capstones

Staphylococcus aureus is a potentially virulent bacterium that causes mastitis in dairy cattle. The toxins produced from S. aureus impact host immunity, damage the mammary gland, and can adapt to cause antimicrobial resistance. It is important to manage both organic and conventional farms correctly by practicing proper hygiene while milking and providing a clean environment. There is a significant increase of S. aureus cases on organic farms compared to conventional, so there may be ways in which organic management and treatment options could be altered to reduce economic loss and animal suffering. The thesis focuses on the involvement S. aureus …

Death Of A Bacterium: Exploring The Inhibition Of Staphylococcus Aureus By Burkholderia Cenocepacia., Tiffany Brandt

Electronic Theses and Dissertations

Antimicrobial resistance is a phenomenon of increasing concern as antimicrobial overuse and misuse eliminate current therapeutic options, ushering society into a post-antimicrobial era. Antibiotic discovery and synthesis efforts are urgently needed to counter the increasing burden of antimicrobial resistance. Staphylococcus aureus is a causative agent of a variety of clinical manifestations including bacteremia, endocarditis, soft tissue infection, osteomyelitis, and device-related infections. S. aureus infection presents additional treatment challenges due to its capacity for biofilm formation, which is a mode of growth that confers protection from antibiotics and physical elimination, and the emergence of antibiotic resistant strains, including methicillin-resistant S. aureus …

Study Of The Role Of The Msaabcr Operon In Tricarboxylic Acid Cycle Activity And Persister Cell Formation In Staphylococcus Aureus, Karsen Motter

Honors Theses

Staphylococcus aureus is an important human pathogen that causes wide arrays of infections ranging from minor skin infections to lethal systemic conditions such as infective endocarditis, osteomyelitis, sepsis and pneumonia. These systemic diseases are often difficult to treat due to the presence of persister cells. Persister cells are a phenotypic variant of the bacterial population that exhibit extreme and transient antibiotic tolerance accompanied by a transient halt in growth. Upon cessation of antibiotic treatment, however, persisters resume growth which results in recurrence of infections. This characteristic of persister cells therefore displays high clinical significance. In this study, we show the …

Interregulation Between Msaabcr Operon And Ccpe To Determine Staphylococcal Metabolism And Virulence, Erin R. Cox

Honors Theses

Staphylococcus aureus is a complex human pathogen that causes problems in both healthcare and community settings. Staphylococcus aureus is a gram-positive, sphere shaped bacterium that usually colonizes in the nasal cavity of healthy individuals. Staphylococcus aureus infections are a growing health concern due to its ability to produce virulence factors, such as pigmentation, protease production, and capsule formation. Two regulators in S. aureus virulence factors are msaABCR, which is a newly characterized operon, and ccpE. In order to determine the interaction between these two regulators in regulating virulence and metabolism in S. aureus, ccpE and ccpE/ …

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 …

Biofilm Associated Staphylococcus Aureus Viability Is Altered By Burkholderia Cenocepacia, Bridget Wall, Tiffany J. Brandt, Dr. Deborah Yoder-Himes

Undergraduate Arts and Research Showcase

Respiratory failure caused by chronic and recurrent microbial infections is the most common cause of death for people with cystic fibrosis (CF)¹, a disease causing the formation of thick mucus in the lungs². Most bacteria can form biofilms, collections of sessile cells adhered to a surface by a secreted substance. Biofilm-associated cells develop antibiotic resistance at higher rates³. The thicker mucus in CF lungs is extremely difficult to clear via action of the mucociliary escalator and its presence fosters the formation of bacterial biofilms. Staphylococcus aureus and Burkholderia cenocepacia are two pathogens commonly found …

Mass Spectrometry Based Lipidomic Investigation Of Staphylococcus Aureus Lipid Metabolism And Characterization Of Lipase A, Naren Gajenthra Kumar

Theses and Dissertations

Staphylococcus aureus produces an arsenal of virulence factors and is adept at colonizing multiple hosts by employing specific processes to persist at different sites of infection. Infections caused by this pathogen range from self-limiting infections of the skin like folliculitis to life threatening and chronic conditions like infective endocarditis, non-healing diabetic foot ulcers and atopic dermatitis. As the field continues to expand its understanding of the mechanisms by which this pathogen rapidly develops resistance to new antibiotics, the underlying mechanisms that facilitates niche adaptation and host colonization among healthy individuals remain elusive.

Bacterial and host lipid metabolism presents and area …

Combating Drug Resistance - Comparison Of The Antibiotic Effect Of Hydrastis Canadensis Extract And Pure Berberine Via Minimum Inhibitory Concentration Assay, William Luke Scott, Timothy D. Trott

Research in Biology

Herbal medicines are a melee of complex organic chemicals, making it difficult to ascertain their direct mechanism of action. In contrast to mainstream pharmaceuticals, it is argued that herbal medicines are effective because of multiple constituents working synergistically. The complexity of herbal medicines may give them advantages over simpler pharmaceuticals in combating antibiotic resistant microbes, but these advantages can be difficult to quantitate. Popular literature frequently espouses the healing properties of herbal medicines, but many of these claims are not scientifically supported. Many gains could be realized in public health and medicine if more research was aimed at validating / …

The Characterization Of The Transcription Factor Msab And Its Role In Staphylococcal Virulence, Justin Batte

Dissertations

Staphylococcus aureus is a common human pathogen that is responsible for a wide range of infections, ranging from relative minor skin infections to life-threatening disease such as bacteremia, septicemia, and endocarditis. S. aureus possesses many different virulent factors that aid in its ability to cause this wide array of infections. One major virulence factor includes the production of capsular polysaccharide (CP). The production of CP plays a major role in the virulence response during infection specifically by providing S. aureus an antiphagocytic mechanism that allows the pathogen to evade phagocytosis during an infection. S. aureus has developed complex genetic regulatory …

Molecular Subtyping Of Staphylococcus Aureus Isolates From The U.P. Community For The Presence Of Toxin-Encoding Genes, Carol I. Kessel

All NMU Master's Theses

Staphylococcus aureus is the most common cause of human bacterial infections; however, humans can also be asymptomatically colonized with S. aureus. Asymptomatic carriers can potentially spread S. aureus infection to others. These infections can range from mild to severe. The pathology of a S. aureus infection is often dependent on which toxins are expressed and the virulence factors with which they are associated. One goal of this study was to isolate S. aureus from healthy, consenting adult volunteers who submitted nasal swabs for culture and qRT-PCR analysis to determine which strains are present in the community. This knowledge could …

Fluid Dynamic Factors As A Cause And Effect Of Biofilm Formation Of Staphylococcus Aureus Biofilms, Erica Sherman

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Staphylococcus aureus bacteria are able to form biofilms and distinctive tower structures that facilitate their ability to tolerate treatment and to spread within the human body. The formation of towers, which break off, get carried downstream and serve to initiate biofilms in other parts of the body are of particular interest here. It is known that flow conditions play a role in the development, dispersion and propagation of biofilms. The influence of flow on tower formation and what factors lead to tower formation is not at all understood The hypothesis being examined is that tower structures form within a specific …

A Novel And Rapid Staphylococcus Aureus Bacterial Identification Method Utilizing Immunomagnetic Beads And Single Cell Laser-Light Scattering, Kaylagh Hollen

All NMU Master's Theses

Staphylococcus aureus is the most commonly isolated human associated bacterial pathogen. It plays an important role in skin and soft-tissue infections, pneumonia, endocarditis, osteomyelitis, foreign-body infections, and sepsis. S. aureus diagnosis and treatment requires a minimum of 24-48. With this in mind, previous studies suggest that faster pathogen identification has been linked to improved patient outcomes. Improved patient outcomes including a reduction in hospitalization time, decreased risk of nosocomial infections, and decreased in medical costs. The impact of faster identification on patient outcome has led us to develop an alternative method of S. aureus identification via ImmunoMagnetic Separation (IMS) and …

Regulation Of Vancomycin Resistance And Stress Response By The Msaabcr Operon In Staphylococcus Aureus, Dhritiman Samanta

Dissertations

Staphylococcus aureus is the predominant cause of public health problems around the world. Vancomycin has been an important antibiotic against Methicillin Resistant Staphylococcus aureus (MRSA) infections. However, Vancomycin Intermediate S. aureus (VISA) strains have been reported. These strains are characterized by thick cell walls, reduced autolytic rate, reduced PBP4 activity, and increased amount of D-Ala-D-Ala termini in the cell wall. In this study, we show that the msaABCR operon regulates vancomycin resistance in two clinical VISA strains. Deletion of the msaABCR operon in strains Mu50 and HIP6297 resulted in a significant decrease in the minimum inhibitory concentration (MIC) for vancomycin. …

Transduction As The Method Of Horizontal Gene Transfer Of The Staphylococcal Chromosomal Cassette Mec (Sccmec), Amber B. Sauder

Senior Honors Projects, 2010-2019

Methicillin-resistant Staphylococcus aureus (MRSA) gains resistance to β-lactam antibiotics through a mutated penicillin binding protein (PBP2a) encoded on the SCCmec element. In combination with the recombinase encoded by ccr, these two genes are used as markers of the mobile genetic element (SCCmec). Due to recent increases in community acquired MRSA infections, the mechanisms of antibiotic resistance gene transfer have gained attention. Transduction, a method of horizontal gene transfer mediated by bacteriophage, is believed to be responsible for the movement of the SCCmec element. Recent studies have shown the transduction of the SCCmec element in clinical isolates; however, this study is …

Characterization Of The Interactions Between Staphylococcal Phage 80 Alpha Scaffold And Capsid Proteins, Laura Klenow

Theses and Dissertations

Staphylococcal phage 80α can serve as a helper bacteriophage for a family of mobile genetic elements called Staphylococcus aureus pathogenicity islands (SaPIs). The prototype island, SaPI1, is able to hijack the 80α capsid assembly process and redirect capsid formation to yield smaller, phage-like transducing particles carrying SaPI DNA. Capsid size redirection is accomplished through two SaPI1-encoded gene products, CpmA and an alternate scaffold protein, CpmB. The normal 80α scaffold and the SaPI1 CpmB scaffold share a small block of conserved residues at their C-termini, several of which had been shown to be essential for CpmB function. This led to the …

An Evaluation Of Methicillin Resistant Staphylococcus Aureus Survival On Five Environmental Surfaces Under Two Different Humidities, With And Without The Addition Of Bovine Serum Albumin, Courtney Ann Coughenour

UNLV Theses, Dissertations, Professional Papers, and Capstones

The spread of antibiotic resistant bacteria is a major public health concern, as they result in greater healthcare costs and increased morbidity and mortality rates. Methicillin resistant Staphylococcus aureus (MRSA) is one organism of particular concern, with the number of infections increasing in epidemic proportion. Bacterial surface contamination with MRSA is significant, as it may serve as a reservoir for transmission and have negative health implications. The purpose of this study was to evaluate survival of MRSA on five environmental surface materials; glass, wood, vinyl, plastic, and cloth. The effect of relative humidity (RH) and bovine serum albumin (BSA) were …