Medicine and Health Sciences Commons^™

Quorum-Sensing, Magdalena Podkowik, Andrew I Perault, Gregory Putzel, Andrew Pountain, Jisun Kim, Ashley L Dumont, Erin E Zwack, Robert J Ulrich, Theodora K Karagounis, Chunyi Zhou, Andreas F Haag, Julia Shenderovich, Gregory A Wasserman, Junbeom Kwon, John Chen, Anthony R Richardson, Jeffrey N Weiser, Carla R Nowosad, Desmond S Lun, Dane Parker, Alejandro Pironti, Xilin Zhao, Karl Drlica, Itai Yanai, Victor J Torres, Bo Shopsin

Journal Articles

The agr quorum-sensing system links Staphylococcus aureus metabolism to virulence, in part by increasing bacterial survival during exposure to lethal concentrations of H2O2, a crucial host defense against S. aureus. We now report that protection by agr surprisingly extends beyond post-exponential growth to the exit from stationary phase when the agr system is no longer turned on. Thus, agr can be considered a constitutive protective factor. Deletion of agr resulted in decreased ATP levels and growth, despite increased rates of respiration or fermentation at appropriate oxygen tensions, suggesting that Δagr cells undergo a shift towards a hyperactive metabolic …

Granulocytic Myeloid-Derived Suppressor Cell Activity During Biofilm Infection Is Regulated By A Glycolysis/Hif1a Axis, Christopher M. Horn, Prabhakar Arumugam, Zachary Van Roy, Cortney E. Heim, Rachel W. Fallet, Blake P. Bertrand, Dhananjay Shinde, Vinai Chittezham Thomas, Svetlana Romanova, Tatiana K. Bronich, Curtis Hartman, Kevin Garvin, Tammy Kielian

Journal Articles: Pathology and Microbiology

Staphylococcus aureus is a leading cause of biofilm-associated prosthetic joint infection (PJI). A primary contributor to infection chronicity is an expansion of granulocytic myeloid-derived suppressor cells (G-MDSCs), which are critical for orchestrating the antiinflammatory biofilm milieu. Single-cell sequencing and bioinformatic metabolic algorithms were used to explore the link between G-MDSC metabolism and S. aureus PJI outcome. Glycolysis and the hypoxia response through HIF1a were significantly enriched in G-MDSCs. Interfering with both pathways in vivo, using a 2-deoxyglucose nanopreparation and granulocyte-targeted Hif1a conditional KO mice, respectively, attenuated G-MDSC-mediated immunosuppression and reduced bacterial burden in a mouse model of S. aureus PJI. …

A Rare Case Of Iga Vasculitis In An Adult Patient With Mssa Bacteremia And Prostate Abscess, Maria E Mesalles, Erinolaoluwa F Araoye, Anees Siddiqi, Adrien Janvier

Journal of Community Hospital Internal Medicine Perspectives

IgA vasculitis, previously known as Henoch Schönlein Purpura (HSP), is a disease more common in children and occurs when IgA1 immune complexes attach to the walls of small blood vessels causing inflammation. This case report is of an adult male who presented with a purpuric rash affecting both legs, microhematuria, and knee pain. Blood cultures were positive for Methicillin-sensitive Staphylococcus aureus (MSSA). Computed tomography of the pelvis revealed a prostate abscess. Skin biopsy demonstrated IgA and C3 in the dermal vessels. To our knowledge, this is the first report of IgA vasculitis associated with MSSA bacteremia due to a prostate …

Metabolism Shapes Immune Responses To Staphylococcus Aureus., Prabhakar Arumugam, Tammy Kielian

Journal Articles: Pathology and Microbiology

BACKGROUND: Staphylococcus aureus (S. aureus) is a common cause of hospital- and community-acquired infections that can result in various clinical manifestations ranging from mild to severe disease. The bacterium utilizes different combinations of virulence factors and biofilm formation to establish a successful infection, and the emergence of methicillin- and vancomycin-resistant strains introduces additional challenges for infection management and treatment.

SUMMARY: Metabolic programming of immune cells regulates the balance of energy requirements for activation and dictates pro- versus anti-inflammatory function. Recent investigations into metabolic adaptations of leukocytes and S. aureus during infection indicate that metabolic crosstalk plays a crucial role in …

Elucidating Granulocytic Myeloid-Derived Suppressor Cell Heterogeneity During Staphylococcus Aureus Biofilm Infection, Blake P. Bertrand, Cortney E. Heim, Scott A. Koepsell, Tammy Kielian

Journal Articles: Pathology and Microbiology

Myeloid-derived suppressor cells (MDSCs) are pathologically activated immature myeloid cells with immunosuppressive activity that expand during chronic inflammation, such as cancer and prosthetic joint infection (PJI). Myeloid-derived suppressor cells can be broadly separated into 2 populations based on surface marker expression and function: monocytic myeloid-derived suppressor cells (M-MDSCs) and granulocytic myeloid-derived suppressor cells (G-MDSCs). Granulocytic myeloid-derived suppressor cells are the most abundant leukocyte infiltrate during PJI; however, how this population is maintained in vivo and cellular heterogeneity is currently unknown. In this study, we identified a previously unknown population of Ly6G+Ly6C+F4/80+MHCII+ MDSCs during PJI that displayed immunosuppressive properties ex vivo. …

Metabolic Diversity Of Human Macrophages: Potential Influence On Staphylococcus Aureus Intracellular Survival, Blake P. Bertrand, Dhananjay Shinde, Vinai C. Thomas, Marvin Whiteley, Carolyn B. Ibberson, Tammy Kielian

Journal Articles: Pathology and Microbiology

Staphylococcus aureus is a leading cause of medical device-associated biofilm infections. This is influenced by the ability of S. aureus biofilm to evade the host immune response, which is partially driven by the anti-inflammatory cytokine interleukin-10 (IL-10). Here, we show that treatment of human monocyte-derived macrophages (HMDMs) with IL-10 enhanced biofilm formation, suggesting that macrophage anti-inflammatory programming likely plays an important role during the transition from planktonic to biofilm growth. To identify S. aureus genes that were important for intracellular survival in HMDMs and how this was affected by IL-10, transposon sequencing was performed. The size of the S. aureus …

Nanosecond Pulsed Electric Fields Increase Antibiotic Susceptibility In Methicillin-Resistant Staphylococcus Aureus, Alexandra E. Chittams-Miles, Areej Malik, Erin B. Purcell, Claudia Muratori

Bioelectrics Publications

Staphylococcus aureus is the leading cause of skin and soft-tissue infections (SSTIs). SSTIs caused by bacteria resistant to antimicrobials, such as methicillin-resistant S. aureus (MRSA), are increasing in incidence and have led to higher rates of hospitalization. In this study, we measured MRSA inactivation by nanosecond pulsed electric fields (nsPEF), a promising new cell ablation technology. Our results show that treatment with 120 pulses of 600 ns duration (28 kV/cm, 1 Hz), caused modest inactivation, indicating cellular damage. We anticipated that the perturbation created by nsPEF could increase antibiotic efficacy if nsPEF were applied as a co-treatment. To test this …

Nasal Iodophor Antiseptic Vs Nasal Mupirocin Antibiotic In The Setting Of Chlorhexidine Bathing To Prevent Infections In Adult Icus: A Randomized Clinical Trial, Susan S Huang, Edward J Septimus, Ken Kleinman, Lauren T Heim, Julia A Moody, Taliser R Avery, Laura Mclean, Syma Rashid, Katherine Haffenreffer, Lauren Shimelman, Whitney Staub-Juergens, Caren Spencer-Smith, Selsebil Sljivo, Ed Rosen, Russell E Poland, Micaela H Coady, Chi Hyun Lee, Eunice J Blanchard, Kimberly Reddish, Mary K Hayden, Robert A Weinstein, Brandon Carver, Kimberly Smith, Jason Hickok, Karen Lolans, Nadia Khan, S Gwynn Sturdevant, Sujan C Reddy, John A Jernigan, Kenneth E Sands, Jonathan B Perlin, Richard Platt

Journal Articles

IMPORTANCE: Universal nasal mupirocin plus chlorhexidine gluconate (CHG) bathing in intensive care units (ICUs) prevents methicillin-resistant Staphylococcus aureus (MRSA) infections and all-cause bloodstream infections. Antibiotic resistance to mupirocin has raised questions about whether an antiseptic could be advantageous for ICU decolonization.

OBJECTIVE: To compare the effectiveness of iodophor vs mupirocin for universal ICU nasal decolonization in combination with CHG bathing.

DESIGN, SETTING, AND PARTICIPANTS: Two-group noninferiority, pragmatic, cluster-randomized trial conducted in US community hospitals, all of which used mupirocin-CHG for universal decolonization in ICUs at baseline. Adult ICU patients in 137 randomized hospitals during baseline (May 1, 2015-April 30, 2017) …

Defining The Roles Of Pyruvate Oxidation, Tca Cycle, And Mannitol Metabolism In Methicillin-Resistant Staphylococcus Aureus Catheter-Associated Urinary Tract Infection, Santosh Paudel, Sarah Guedry, Chloe L P Obernuefemann, Scott J. Hultgren, Jennifer N. Walker, Ritwij Kulkarni

2020-Current year OA Pubs

Methicillin-resistant Staphylococcus aureus (MRSA) is an important cause of complicated urinary tract infection (UTI) associated with the use of indwelling urinary catheters. Previous reports have revealed host and pathogen effectors critical for MRSA uropathogenesis. Here, we sought to determine the significance of specific metabolic pathways during MRSA UTI. First, we identified four mutants from the Nebraska transposon mutant library in the MRSA JE2 background that grew normally in rich medium but displayed significantly reduced growth in pooled human urine (HU). This prompted us to transduce the uropathogenic MRSA 1369 strain with the transposon mutants in

Paravertebral Abscess Secondary To Vertebral Osteomyelitis In An Intravenous Drug User., Marianne Cortes, Taylor Mazzei, Anuj Khanna, Kira Fenton, Cristina Savu

HPD Articles

Hematogenous pyogenic vertebral osteomyelitis (VO) is a rare and often fatal complication of osteomyelitis that can affect individuals with underlying medical conditions, hospital-acquired infections, and intravenous (IV) drug abuse. Pyogenic vertebral osteomyelitis can present with generalized back pain, pyrexia, motor weakness, and neurologic deficits. The enigmatic presentation of this condition often results in delays in diagnosis and an increase in mortality. This case report aims to bring awareness to complications of hematogenous pyogenic vertebral osteomyelitis as well as highlight the need for further studies in order to establish standardized treatment. In our report, we depict a case of complicated pyogenic …

A Review Of Staphylococcus Aureus Pathogenesis, Global Impact, And The Rise Of Antibiotic-Resistant Clones, Anders Kleinbeck

Honors Scholar Theses

Staphylococcus aureus is a pathogen of grave concern to global public health. The pathogen has shown an unrivaled propensity to obtain resistance to nearly every antibiotic drug approved and prescribed for its treatment. This review will provide an overview of the history and evolution of S. aureus, including an analysis of its transition from the nosocomial setting to the community and the factors contributing to the species’ innate pathogenicity. This paper will also discuss the molecular mechanisms by which resistance to a wide range of popular antibiotic substances was obtained and will provide insight into the evolutionary patterns exhibited by …

Early Diagnosis Of Purulent Pericarditis Secondary To Methicillin-Sensitive Staphylococcus Aureus In An End-Stage Renal Disease Patient, Stephen Shey, Alejandro Espinosa-Tello, Amnah Andrabi

North Texas GME Research Forum 2023

Introduction Purulent pericarditis is a rare illness in the modern age of medicine due to the increased usage of antibiotics. Unfortunately, diagnosis of this disease is often delayed due to its nonspecific symptoms. Without treatment, the mortality is nearly one hundred percent due to major complications such as cardiac tamponade and constrictive pericarditis. As a result, most cases of purulent pericarditis are discovered post-mortem. This case report details an early diagnosis of purulent pericarditis secondary to methicillin-sensitive Staphylococcus aureus (MSSA) in an end-stage renal disease (ESRD) patient. Case Presentation A 66-year-old female with past medical history of ESRD initially presented …

Microbubble Cavitation Restores Staphylococcus Aureus Antibiotic Susceptibility In Vitro And In A Septic Arthritis Model, Neil Zhao, Dylan Curry, Rachel E Evans, Selin Isguven, Theresa A. Freeman, John R. Eisenbrey, Flemming Forsberg, Jessica M Gilbertie, Sophie Boorman, Rachel Hilliard, Sana S. Dastgheyb, Priscilla Machado, Maria Stanczak, Marc I. Harwood, Antonia F Chen, Javad Parvizi, Irving Shapiro, Noreen J. Hickok, Thomas P Schaer

Department of Orthopaedic Surgery Faculty Papers

Treatment failure in joint infections is associated with fibrinous, antibiotic-resistant, floating and tissue-associated Staphylococcus aureus aggregates formed in synovial fluid (SynF). We explore whether antibiotic activity could be increased against Staphylococcus aureus aggregates using ultrasound-triggered microbubble destruction (UTMD), in vitro and in a porcine model of septic arthritis. In vitro, when bacterially laden SynF is diluted, akin to the dilution achieved clinically with lavage and local injection of antibiotics, amikacin and ultrasound application result in increased bacterial metabolism, aggregate permeabilization, and a 4-5 log decrease in colony forming units, independent of microbubble destruction. Without SynF dilution, amikacin + UTMD does …

Berberine Disrupts Staphylococcal Proton Motive Force To Cause Potent Anti-Staphylococcal Effects, Neil Zhao, Selin Isguven, Rachel Evans, Thomas P Schaer, Noreen J. Hickok

Department of Orthopaedic Surgery Faculty Papers

The presence of antibiotic resistance has increased the urgency for more effective treatments of bacterial infections. Biofilm formation has complicated this issue as biofilm bacteria become tolerant to antibiotics due to environmental factors such as nutrient deprivation and adhesion. In septic arthritis, a disease with an 11% mortality rate, bacteria in synovial fluid organize into floating, protein-rich, bacterial aggregates (mm-cm) that display depressed metabolism and antibiotic tolerance. In this study, Staphylococcus aureus (S. aureus), which is the most common pathogen in septic arthritis, was tested against different inhibitors that modulate bacterial surface protein availability and that should decrease bacterial aggregation. …

Staphylococcus Aureus Breast Implant Infection Isolates Display Recalcitrance To Antibiotic Pocket Irrigants, Jesus M. Duran Ramirez, Jana Gomez, Blake M. Hanson, Taha Isa, Terence M. Myckatyn, Jennifer N. Walker

2020-Current year OA Pubs

Breast implant-associated infections (BIAIs) are the primary complication following placement of breast prostheses in breast cancer reconstruction. Given the prevalence of breast cancer, reconstructive failure due to infection results in significant patient distress and health care expenditures. Thus, effective BIAI prevention strategies are urgently needed. This study tests the efficacy of one infection prevention strategy: the use of a triple antibiotic pocket irrigant (TAPI) against Staphylococcus aureus, the most common cause of BIAIs. TAPI, which consists of 50,000 U bacitracin, 1 g cefazolin, and 80 mg gentamicin diluted in 500 mL of saline, is used to irrigate the breast implant …

Prognostic Significance Of Early Platelet Dynamics In Staphylococcus Aureus Bacteremia, Rachid Douglas-Louis, Mimi Lou, Brian Lee, Emi Minejima, Juliane Bubeck-Wardenburg, Annie Wong-Beringer

2020-Current year OA Pubs

BACKGROUND: Platelets are recognized as key immune effectors, but they are targets of bacterial virulence factors. In the present study, we aimed to examine the relationship between early platelet dynamics and the outcome of Staphylococcus aureus bacteremia (SAB).

METHOD: Electronic medical records of adult patients hospitalized for SAB between July 2012 and November 2020 were retrospectively reviewed for relevant demographic, laboratory, and clinical data. The outcome endpoints were mortality and microbial persistence.

RESULTS: Among the 811 patients evaluated, 29% experienced thrombocytopenia on Day 1. Platelet count nadir occurred on Days 2-3 following SAB onset, and Day 4 was a determining …

Antibacterial And Antifungal Activity Of Methanolic Extracts Of Salix Alba L. Against Various Disease Causing Pathogens, Bilal Javed, F. Farooq, M. Ibrahim, H.A.B. Abbas, H. Jawwad, S.S. Zehra, H.M. Ahmad, A. Sarwar, K. Malik, K. Nawaz

Articles

The present study was aimed to manifest the antibacterial and antifungal activity of methanolic extracts of Salix alba L. against seven Gram-positive and Gram-negative bacterial pathogens e.g. Streptococcus pyogenes, Staphylococcus aureus (1), S. aureus (2), Shigella sonnei, Escherichia coli (1), E. coli (2) and Neisseria gonorrhoeae and three fungal isolates from the air such as Aspergillus terreus, A. ornatus, and Rhizopus stolonifer. Two different serotypes of S. aureus and E. coli were used. The agar well-diffusion method results showed the dose-dependent response of plant extracts against bacterial and fungal strains while some organisms were found resistant e.g. E. coli (1), …

Characterisation And Antibacterial Activity Of Green Tea Extract-Enriched Solid Goat’S Milk Soap, Uswatun Chasanah, Dian Ermawati, Dwi Putri Utami, Angela Nora Hayati

Pharmaceutical Sciences and Research

Solid goat’s milk soap is organic and beneficial for the health and appearance of the skin. One of the components in green tea known to display antibacterial activities is epigallocatechin gallate (ECGC). In this study, the effects of solid goat’s milk soap containing 1%, 2%, and 4% green tea extract on the growth of Propionibacterium acnes, Staphylococcus aureus, and Staphylococcus epidermidis were examined. The soap was characterized for its organoleptic, pH, free fatty acid, alkalinity, water content, foam stability, and hardness. In addition, an in vitro antimicrobial test was performed utilising the well-diffusion method. The findings revealed that all the …

Tetr Family Regulator Farr Variation Controls Antimicrobial Fatty Acid Efflux In Staphylococcus Aureus, Camryn M. Bonn

Electronic Thesis and Dissertation Repository

To colonize human skin and survive within abscesses, Staphylococcus aureus has evolved mechanisms to evade host innate defenses. USA300 has become the predominate community-acquired methicillin-resistant S. aureus (CA-MRSA) clone, which can be in part attributed to detoxification of unsaturated free fatty acids (uFFA) found in sebum and the nares. Our lab has previously identified the TetR family regulator FarR responsible for induction of the resistance-nodulation-division (RND) superfamily efflux pump FarE to promote efflux of toxic uFFA. However, RND family efflux pumps remain poorly characterized in Gram-positive species and the mechanism by which FarR regulates FarE has yet to be determined. …

Worsening Glycemia Increases The Odds Of Intermittent But Not Persistent Staphylococcus Aureus Nasal Carriage In Two Cohorts Of Mexican American Adults, Heather T Essigmann, Craig L Hanis, Stacia M Desantis, William B Perkison, David A Aguilar, Goo Jun, D Ashley Robinson, Eric L Brown

Journal Articles

Numerous host and environmental factors contribute to persistent and intermittent nasal Staphylococcus aureus carriage in humans. The effects of worsening glycemia on the odds of S. aureus intermittent and persistent nasal carriage was established in two cohorts from an adult Mexican American population living in Starr County, Texas. The anterior nares were sampled at two time points and the presence of S. aureus determined by laboratory culture and

Antigenic Landscapes On Staphylococcus Aureus Pore-Forming Toxins Reveal Insights Into Specificity And Cross-Neutralization, Shweta Kailasan, Ravi Kant, Madeleine Noonan-Shueh, Tulasikumari Kanipakala, Grant Liao, Sergey Shulenin, Daisy W Leung, Richard A Alm, Rajan P Adhikari, Gaya K Amarasinghe, Michael L Gross, M Javad Aman

2020-Current year OA Pubs

No abstract provided.

Safety And Efficacy Of Silver-Coated Biomaterials In Vivo, Megan Klem, Darien L. Seidman, Rahyan Mahmoud, Manuella Adu, Lei Yu, Jeffrey Hettinger, Renee M Demarest

Rowan-Virtua Research Day

Overtreatment and overuse of antibiotics in healthcare and agricultural settings have contributed to the selective pressure on bacterial strains to develop resistance. Resistance can develop as a result of mutations and subsequent resistance genes that allow bacteria to survive against antibiotics. Novel silver-oxide coatings were developed and were previously demonstrated to prevent adhesion of gram-negative bacteria (Escherichia Coli and Pseudomonas Aeruginosa) to the disc, but did not prevent gram-positive bacterial adherence (Streptococcus Aureus). In order to determine whether the silver-oxide coatings are bacterial static and may be preventing progression to biofilm formation, in vivo analysis of S. Aureus attached to …

Predominantly Methicillin-Susceptible S. Aureus Bacteria Found In Csp Students’ S. Aureus Strains, Roma Ambo

Research and Scholarship Symposium Posters

Positive Staphylococcus aureus strains from CSP students were tested for methicillin resistance (MRSA) using the Kirby-bauer assay. Kirby-bauer assay technique was used to determine the sensitivity of staphylococcus aureus bacteria against oxacillin. MRSA infection is the result of a bacteria that has built resistance against the antibiotics used to treat staph infections. The results of this experiment concludes that majority of the strains tested are methicillin-susceptible S. aureus (MSSA).

Study Of Glucose Supplementation On Antibiotic Efficacy Against Staphylococcus Aureus, Areej Malik, Alexandra E. Chittams-Miles, Claudia Muratori, Erin B. Purcell

College of Sciences Posters

Staphylococcus aureus (S. aureus), is a Gram-positive, facultative anaerobic, biofilm-forming bacterium. It is the leading cause of skin and soft tissue infections (SSTIs) in the United States. The public health impact of S. aureus has been increased by the emergence of Methicillin-resistant Staphylococcus aureus. It has also shown intermediate resistance to Vancomycin, which suggests that full resistance may develop. It is known that hyperglycemia (high blood sugar) from diabetes reduces immune system function. Patients with diabetes experience a greater rate of skin and soft tissue infections. This research explores the effect of increasing glucose concentration on S. …

Compliance With Guidelines For Treatment Of Staphylococcus Aureus Bacteremia Is Associated With Decreased Mortality In Patients Hospitalized For Community-Acquired Pneumonia With Staphylococcus Aureus Bacteremia, Leslie Beavin, Vidyulata Salunkhe, Shashvin Singh, Ahmed Gana, Balaji Sekaran, Mahder A. Tella, Stephen P. Furmanek, Forest W. Arnold

The University of Louisville Journal of Respiratory Infections

Introduction: Staphylococcus aureus bacteremia has a minimum treatment duration of two weeks, while S. aureus community-acquired pneumonia (CAP) treatment is at least five days. Treatment failure, persistent bacteremia, and recurrence are common among patients with community-acquired S. aureus bacteremia. There is conflicting information in the current Infectious Diseases Society of America (IDSA) guidelines for the treatment of S.aureus bacteremia patients with CAP. Therefore, the appropriate treatment duration and modality for S. aureus CAP with bacteremia is unclear. The objective of this study was to compare outcomes among patients with S. aureus CAP and bacteremia treated in compliance versus non-compliance with …

Comparison Of Automated Ribotyping, Spa Typing, And Mlst In 108 Clinical Isolates Of Staphylococcus Aureus From Orthopedic Infections, Stefano Ravaioli, Davide Campoccia, Werner Ruppitsch, Franz Allerberger, Alessandro Poggi, Emanuele Chisari, Lucio Montanaro, Carla Renata Arciola

Rothman Institute Faculty Papers

108 isolates of Staphylococcus aureus, belonging to six large ribogroups according to the automated Ribo-Printer® system, were studied with two highly used molecular methods for epidemiological studies, namely multi-locus sequence typing (MLST) and spa typing, followed by BURP and eBURST v3 analysis for clustering spa types and sequence (ST) types. The aim was to evaluate whether automated ribotyping could be considered a useful screening tool for identifying S. aureus genetic lineages with respect to spa typing and MLST. Clarifying the relationship of riboprinting with these typing methods and establishing whether ribogroups fit single clonal complexes were two main objectives. …

Engineering A "Detect And Destroy" Skin Probiotic To Combat Methicillin-Resistant Staphylococcus Aureus., Changhui Guan, Peter J Larson, Elizabeth Fleming, Alexander P Tikhonov, Sara Mootien, Trudy H Grossman, Caroline Golino, Julia Oh

Faculty Research 2022

The prevalence and virulence of pathogens such as methicillin-resistant Staphylococcus (S.) aureus (MRSA), which can cause recurrent skin infections, are of significant clinical concern. Prolonged antibiotic exposure to treat or decolonize S. aureus contributes to development of antibiotic resistance, as well as depletion of the microbiome, and its numerous beneficial functions. We hypothesized an engineered skin probiotic with the ability to selectively deliver antimicrobials only in the presence of the target organism could provide local bioremediation of pathogen colonization. We constructed a biosensing S. epidermidis capable of detecting the presence of S. aureus quorum sensing autoinducer peptide and producing lysostaphin …

Nh125 Sensitizes Staphylococcus Aureus To Cell Wall-Targeting Antibiotics Through The Inhibition Of The Vras Sensor Histidine Kinase, Shrijan Bhattarai, Lane Marsh, Kelsey Knight, Liaqat Ali, Antonio Gomez, Allison Sunderhaus, May H. Abdelaziz

Pharmacy Faculty Publications and Presentations

Staphylococcus aureus utilizes the two-component regulatory system VraSR to receive and relay environmental stress signals, and it is implicated in the development of bacterial resistance to several antibiotics through the upregulation of cell wall synthesis. VraS inhibition was shown to extend or restore the efficacy of several clinically used antibiotics. In this work, we study the enzymatic activity of the VraS intracellular domain (GST-VraS) to determine the kinetic parameters of the ATPase reaction and characterize the inhibition of NH125 under in vitro and microbiological settings. The rate of the autophosphorylation reaction was determined at different GST-VraS concentrations (0.95 to 9.49 …

The Staphylococcus Aureus Cida And Lrga Proteins Are Functional Holins Involved In The Transport Of By-Products Of Carbohydrate Metabolism, Jennifer L. Endres, Sujata S. Chaudhari, Xinyan Zhang, Janani Prahlad, Shu-Qi Wang, Lily A. Foley, Sorin Luca, Jeffrey L. Bose, Vinai C. Thomas, Kenneth W. Bayles

Journal Articles: Pathology and Microbiology

The Staphylococcus aureus cidABC and lrgAB operons encode members of a well-conserved family of proteins thought to be involved in programmed cell death (PCD). Based on the structural similarities that CidA and LrgA share with bacteriophage holins, we have hypothesized that these proteins function by forming pores within the cytoplasmic membrane. To test this, we utilized a "lysis cassette" system that demonstrated the abilities of the cidA and lrgA genes to support bacteriophage endolysin-induced cell lysis. Typical of holins, CidA- and LrgA-induced lysis was dependent on the coexpression of endolysin, consistent with the proposed holin-like functions of these proteins. In …

Catabolic Ornithine Carbamoyltransferase Activity Facilitates Growth Of Staphylococcus Aureus In Defined Medium Lacking Glucose And Arginine, Itidal Reslane, Cortney R. Halsey, Amanda Stastny, Barbara J. Cabrera, Jong-Sam Ahn, Dhananjay Shinde, Madeline R. Galac, Margaret F. Sladek, Fareha Razvi, Mckenzie K. Lehman, Kenneth W. Bayles, Vinai Chittezham Thomas, Luke D. Handke, Paul D. Fey

Journal Articles: Pathology and Microbiology

Previous studies have found that arginine biosynthesis in Staphylococcus aureus is repressed via carbon catabolite repression (CcpA), and proline is used as a precursor. Unexpectedly, however, robust growth of S. aureus is not observed in complete defined medium lacking both glucose and arginine (CDM-R). Mutants able to grow on agar-containing defined medium lacking arginine (CDM-R) were selected and found to contain mutations within ahrC, encoding the canonical arginine biosynthesis pathway repressor (AhrC), or single nucleotide polymorphisms (SNPs) upstream of the native arginine deiminase (ADI) operon arcA1B1D1C1. Reverse transcription-PCR (RT-PCR) studies found that mutations within ccpA or ahrC or …