Rapid, Reproducible, Quantifiable NMR Metabolomics: Methanol and Methanol: Chloroform Precipitation for Removal of Macromolecules in Serum and Whole Blood.

Background: Though blood is an excellent biofluid for metabolomics, proteins and lipids present in blood can interfere with 1d-¹H NMR spectra and disrupt quantification of metabolites. Here, we present effective macromolecule removal strategies for serum and whole blood (WB) samples.

Methods: A variety of macromolecule removal strategies were compared in both WB and serum, along with tests of ultrafiltration alone and in combination with precipitation methods.

Effect of Antimicrobial and Physical Treatments on Growth of Multispecies Staphylococcal Biofilms.

The prevalence and structure of and within multispecies biofilms were found to depend sensitively on physical environment and antibiotic dosage. Although these species commonly infect similar sites, such as orthopedic implants, little is known about their behavior in multispecies communities, particularly in response to treatment. This research establishes that is much more prevalent than when simultaneously seeded and grown under unstressed conditions (pH 7, 37°C) in both laboratory and clinical strains.

A Cationic Amphiphilic Random Copolymer with pH-Responsive Activity against Methicillin-Resistant Staphylococcus aureus.

In this report, we demonstrate the pH-dependent, in vitro antimicrobial activity of a cationic, amphiphilic random copolymer against clinical isolates of drug-resistant Staphylococcus aureus. The polymer was developed toward a long-term goal of potential utility in the treatment of skin infections. The proposed mechanism of action of the polymer is through selectively binding to bacterial membranes and subsequent disruption of the membrane structure/integrity, ultimately resulting in bacterial cell death.

Making Improvements in the ED: Does ED Busyness Affect Time to Antibiotics in Febrile Pediatric Oncology Patients Presenting to the Emergency Department?

Objectives: Febrile neutropenic pediatric patients are at heightened risk for serious bacterial infections, and rapid antibiotic administration (in <60 minutes) improves survival. Our objectives were to reduce the time-to-antibiotic (TTA) administration and to evaluate the effect of overall emergency department (ED) busyness on TTA.

Methods: This study was a quality improvement initiative with retrospective chart review to reduce TTA in febrile children with underlying diagnosis of cancer or hematologic immunodeficiency who visited the pediatric ED.

Implantable Device-Related Infection.

Over half of the nearly two million healthcare-associated infections can be attributed to indwelling medical devices. In this review, we highlight the difficulty in diagnosing implantable device-related infection and how this leads to a likely underestimate of the prevalence. We then provide a length-scale conceptualization of device-related infection pathogenesis.

Hemodialysis Catheter Heat Transfer for Biofilm Prevention and Treatment.

Central line-associated bloodstream infections (CLABSIs) are not easily treated, and many catheters (e.g., hemodialysis catheters) are not easily replaced.

Artificial biofilms establish the role of matrix interactions in staphylococcal biofilm assembly and disassembly.

We demonstrate that the microstructural and mechanical properties of bacterial biofilms can be created through colloidal self-assembly of cells and polymers, and thereby link the complex material properties of biofilms to well understood colloidal and polymeric behaviors. This finding is applied to soften and disassemble staphylococcal biofilms through pH changes. Bacterial biofilms are viscoelastic, structured communities of cells encapsulated in an extracellular polymeric substance (EPS) comprised of polysaccharides, proteins, and DNA.

Whole Blood Reveals More Metabolic Detail of the Human Metabolome than Serum as Measured by 1H-NMR Spectroscopy: Implications for Sepsis Metabolomics.

Serum is a common sample of convenience for metabolomics studies. Its processing time can be lengthy and may result in the loss of metabolites including those of red blood cells (RBCs). Unlike serum, whole blood (WB) is quickly processed, minimizing the influence of variable hemolysis while including RBC metabolites.

Thermal Augmentation of Vancomycin Against Staphylococcal Biofilms.

Given the increasing evidence of safe application of elevated temperature in other clinical contexts, we consider the potential for supplemental hyperthermia to augment the effects of vancomycin against staphylococci, a major source of postoperative and posttraumatic sepsis. Laboratory reference strains and libraries of clinical blood isolates of Staphylococcus epidermidis and methicillin-resistant Staphylococcus aureus, both as planktonic cells and as established biofilms, were assessed for thermosensitivity and increased susceptibility to vancomycin in the setting of thermal treatment. In addition to viability measures, patterns of stress gene expression were assessed with quantitative polymerase chain reaction, and structural changes were measured using quantitative transmission electron microscopy.

Effects of temperature on the morphological, polymeric, and mechanical properties of Staphylococcus epidermidis bacterial biofilms.

Changes in temperature were found to affect the morphology, cell viability, and mechanical properties of Staphylococcus epidermidis bacterial biofilms. S. epidermidis biofilms are commonly associated with hospital-acquired medical device infections.

Elasticity of microscale volumes of viscoelastic soft matter by cavitation rheometry.

Measurement of the elastic modulus of soft, viscoelastic liquids with cavitation rheometry is demonstrated for specimens as small as 1 l by application of elasticity theory and experiments on semi-dilute polymer solutions. Cavitation rheometry is the extraction of the elastic modulus of a material, E, by measuring the pressure necessary to create a cavity within it [J. A.

Sticky surface: sphere-sphere adhesion dynamics.

We present a multi-scale model to study the attachment of spherical particles with a rigid core, coated with binding ligands and suspended in the surrounding, quiescent fluid medium. This class of fluid-immersed adhesion is widespread in many natural and engineering settings, particularly in microbial surface adhesion. Our theory highlights how the micro-scale binding kinetics of these ligands, as well as the attractive/repulsive surface potential in an ionic medium affects the eventual macro-scale size distribution of the particle aggregates (flocs).

Multilocus Sequence Typing for Interpreting Blood Isolates of Staphylococcus epidermidis.

Staphylococcus epidermidis is an important cause of nosocomial infection and bacteremia. It is also a common contaminant of blood cultures and, as a result, there is frequently uncertainty as to its diagnostic significance when recovered in the clinical laboratory. One molecular strategy that might be of value in clarifying the interpretation of S.

Characterization of a reverse-phase perfluorocarbon emulsion for the pulmonary delivery of tobramycin.

Background: Aerosolized delivery of antibiotics is hindered by poor penetration within distal and plugged airways. Antibacterial perfluorocarbon ventilation (APV) is a proposed solution in which the lungs are partially or totally filled with perfluorocarbon (PFC) containing emulsified antibiotics. The purpose of this study was to evaluate emulsion stability and rheological, antibacterial, and pharmacokinetic characteristics.

Prospective comparison of live evaluation and video review in the evaluation of operator performance in a pediatric emergency airway simulation.

Introduction: Real-time assessment of operator performance during procedural simulation is a common practice that requires undivided attention by 1 or more reviewers, potentially over many repetitions of the same case.

Objective: To determine whether reviewers display better interrater agreement of procedural competency when observing recorded, rather than live, performance; and to develop an assessment tool for pediatric rapid sequence intubation (pRSI).

Methods: A framework of a previously established Objective Structured Assessment of Technical Skills (OSATS) tool was modified for pRSI.

Role of environmental and antibiotic stress on Staphylococcus epidermidis biofilm microstructure.

Cellular clustering and separation of Staphylococcus epidermidis surface adherent biofilms were found to depend significantly on both antibiotic and environmental stress present during growth under steady flow. Image analysis techniques common to colloidal science were applied to image volumes acquired with high-resolution confocal laser scanning microscopy to extract spatial positions of individual bacteria in volumes of size ~30 × 30 × 15 μm(3). The local number density, cluster distribution, and radial distribution function were determined at each condition by analyzing the statistics of the bacterial spatial positions.

Molar mass, entanglement, and associations of the biofilm polysaccharide of Staphylococcus epidermidis.

Biofilms are microbial communities that are characterized by the presence of a viscoelastic extracellular polymeric substance (EPS). Studies have shown that polysaccharides, along with proteins and DNA, are a major constituent of the EPS and play a dominant role in mediating its microstructure and rheological properties. Here, we investigate the possibility of entanglements and associative complexes in solutions of extracellular polysaccharide intercellular adhesin (PIA) extracted from Staphylococcus epidermidis biofilms.

Impact of hourly emergency department patient volume on blood culture contamination and diagnostic yield.

Emergency departments (EDs) are an important diagnostic site for outpatients with potentially serious infections. EDs frequently experience high patient volumes, and crowding has been shown to negatively impact the delivery of early care for serious infections, such as pneumonia. Here, we hypothesized that other important factors in the early care of infectious diseases, the rate of blood culture contamination and the accurate detection of pathogens, would be sensitive to ED operational stress, as proper collection requires fastidious attention to technique and timing.

Complement c5a generation by staphylococcal biofilms.

Biofilms production is a central feature of nosocomial infection of catheters and other medical devices used in resuscitation and critical care. However, the very effective biofilm forming pathogen Staphylococcus epidermidis often produces a modest host inflammatory response and few of the signs and symptoms associated with more virulent pathogens. To examine the impact of bacterial biofilm formation on provocation of an innate immune response, we studied the elaboration of the major complement anaphylatoxin C5a by human serum upon contact with S.

Spatiotemporal dynamics of complement C5a production within bacterial extracellular polymeric substance.

Opsonization and anaphylatoxin production are early events in the innate response to bacterial pathogens. Opsonization alone is frequently not lethal and production of anaphy-latoxins, especially C5a, allows for recruitment of cellular defenses. Complement biochemistry is extensively studied and computational models have been reported previously.

rheology of bacterial biofilms.

We developed a method to grow bacterial biofilms and characterize their rheological properties in a continuously fed bioreactor incorporated into a parallel plate rheometer. The temperature and shear rates of growth modeled bloodstream conditions, a common site of infection. We measured the linear elastic (') and viscous moduli (″) of the material using small-amplitude oscillatory rheology and the yield stress using non-linear creep rheology.

Early development of bacterial community diversity in emergently placed urinary catheters.

Background: Approximately 25% of hospitalized patients have a urinary catheter, and catheter associated urinary tract infection is the most common nosocomial infection in the US, causing >1 million cases/year. However, the natural history of the biofilms that rapidly form on urinary catheters and lead to infection is not well described.

Findings: We characterized the dynamics of catheter colonization among catheters collected from 3 women and 5 men in a trauma burn unit with different indwelling times using TRFLP and culture.