Scholarly Work - Center for Biofilm Engineering
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Item Drastic hourly changes in hand hygiene workload and performance rates: A multicenter time series analysis(Elsevier BV, 2024-09) Moore, Lori D.; Arbogast, James W.; Robbins, Greg; DiGiorgio, Megan; Parker, Albert E.Background. High hand hygiene (HH) workload is a commonly cited barrier to optimal HH performance. The objective of this study was to assess trends of HH workload as defined by HH opportunities (HHO) and performance rates over different timescales using automated HH monitoring system data. Methods. This multiyear retrospective observational study was conducted in 58 inpatient units located in 10 North American hospitals. HHO and HH rates were analyzed by time series mixed effects general additive model. Results. Median HH rates peaked at 50.0 between 6 and 7 AM with a trough of 38.2 at 5 PM. HHO over hours in a day were the highest at 184 per hospital unit per hour at 10 AM with a trough of 49.0 between 2 and 3 AM. Median rates for day and night shifts were 40.8 and 45.5, respectively (P = .078). Weekend day shift had the lowest median rate (39.4) compared with any other 12-hour shift (P < .1018). The median rates and HHO varied little across days in a week and months. Conclusions. HH workload and performance rates were negatively correlated and changed drastically over hours in a day. Hospitals should consider HH workload in the development and timely delivery of improvement interventions.Item Drastic hourly changes in hand hygiene workload and performance rates: a multicenter time series analysis(Elsevier BV, 2024-09) Moore, Lori; Arbogast, James W.; Robbins, Greg; DiGiorgio, Megan; Parker, Albert E.Background. High hand hygiene (HH) workload is a commonly cited barrier to optimal HH performance. The objective of this study was to assess trends of HH workload as defined by HH opportunities (HHO) and performance rates over different timescales using automated HH monitoring system data. Methods. This multiyear retrospective observational study was conducted in 58 inpatient units located in 10 North American hospitals. HHO and HH rates were analyzed by time series mixed effects general additive model. Results. Median HH rates peaked at 50.0 between 6 and 7 AM with a trough of 38.2 at 5 PM. HHO over hours in a day were the highest at 184 per hospital unit per hour at 10 AM with a trough of 49.0 between 2 and 3 AM. Median rates for day and night shifts were 40.8 and 45.5, respectively (P = .078). Weekend day shift had the lowest median rate (39.4) compared with any other 12-hour shift (P < .1018). The median rates and HHO varied little across days in a week and months. Conclusions. HH workload and performance rates were negatively correlated and changed drastically over hours in a day. Hospitals should consider HH workload in the development and timely delivery of improvement interventions.Item Eight genome sequences of bacterial, environmental isolates from Canada Glacier, Antarctica(American Society for Microbiology, 2024-08) Smith, Heidi J.; Dieser, Markus; Foreman, Chrstine M.Sediments in cryoconite holes and meltwater streams in the McMurdo Dry Valleys, Antarctica, provide both substrates and conditions that support life in an arid polar desert. Here, we report the genomic sequences of eight environmental, bacterial isolates from Canada Glacier cryoconite holes and stream. These isolates span three major phyla.Item Clothing Textiles as Carriers of Biological Ice Nucleation Active Particles(American Chemical Society, 2024-03) Teska, Christy J.; Dieser, Markus; Foreman, Christine M.Microplastics have littered the globe, with synthetic fibers being the largest source of atmospheric microplastics. Many atmospheric particles can act as ice nucleators, thereby affecting the microphysical and radiative properties of clouds and, hence, the radiative balance of the Earth. The present study focused on the ice-nucleating ability of fibers from clothing textiles (CTs), which are commonly shed from the normal wear of apparel items. Results from immersion ice nucleation experiments showed that CTs were effective ice nucleators active from −6 to −12 °C, similar to common biological ice nucleators. However, subsequent lysozyme and hydrogen peroxide digestion stripped the ice nucleation properties of CTs, indicating that ice nucleation was biological in origin. Microscopy confirmed the presence of biofilms (i.e., microbial cells attached to a surface and enclosed in an extracellular polysaccharide matrix) on CTs. If present in sufficient quantities in the atmosphere, biological particles (biofilms) attached to fibrous materials could contribute significantly to atmospheric ice nucleation.Item Proteomic and Transcriptomic Analyses Reveal Genes Upregulated by cis-Dichloroethene in Polaromonas sp. Strain JS666(American Society for Microbiology, 2009-06) Jennings, Laura; Chartrand, Michelle; Lacrampe-Couloume, Georges; Sherwood Lollar, Barbara; Spain, Jim C.; Gossett, James M.Polaromonas sp. strain JS666 is the only bacterial isolate capable of using cis-dichloroethene (cDCE) as a sole carbon and energy source. Studies of cDCE degradation in this novel organism are of interest because of potential bioremediation and biocatalysis applications. The primary cellular responses of JS666 to growth on cDCE were explored using proteomics and transcriptomics to identify the genes upregulated by cDCE. Two-dimensional gel electrophoresis revealed upregulation of genes annotated as encoding glutathione S-transferase, cyclohexanone monooxygenase, and haloacid dehalogenase. DNA microarray experiments confirmed the proteomics findings that the genes indicated above were among the most highly upregulated by cDCE. The upregulation of genes with antioxidant functions and the inhibition of cDCE degradation by elevated oxygen levels suggest that cDCE induces an oxidative stress response. Furthermore, the upregulation of a predicted ABC transporter and two sodium/solute symporters suggests that transport is important in cDCE degradation. The omics data were integrated with data from compound-specific isotope analysis (CSIA) and biochemical experiments to develop a hypothesis for cDCE degradation pathways in JS666. The CSIA results indicate that the measured isotope enrichment factors for aerobic cDCE degradation ranged from −17.4 to −22.4‰. Evidence suggests that cDCE degradation via monooxygenase-catalyzed epoxidation (C═C cleavage) may be only a minor degradation pathway under the conditions of these experiments and that the major degradation pathway involves carbon-chloride cleavage as the initial step, a novel mechanism. The results provide a significant step toward elucidation of cDCE degradation pathways and enhanced understanding of cDCE degradation in JS666.Item Coupon position does not affect Pseudomonas aeruginosa and Staphylococcus aureus biofilm densities in the CDC biofilm reactor(Elsevier BV, 2024-08) Buckner, Elizabeth; Buckingham-Meyer, Kelli; Miller, Lindsey A.; Parker, Albert E.; Jones, Christopher J.; Goeres, Darla M.The CDC Biofilm Reactor method is the standard biofilm growth protocol for the validation of US Environmental Protection Agency biofilm label claims. However, no studies have determined the effect of coupon orientation within the reactor on biofilm growth. If positional effects have a statistically significant impact on biofilm density, they should be accounted for in the experimental design. Here, we isolate and quantify biofilms from each possible coupon surface in the reactor to quantitatively determine the positional effects in the CDC Biofilm Reactor. The results showed no statistically significant differences in viable cell density across different orientations and vertical positions in the reactor. Pseudomonas aeruginosa log densities were statistically equivalent among all coupon heights and orientations. While the Staphylococcus aureus cell growth showed no statistically significant differences, the densities were not statistically equivalent among all coupon heights and orientations due to the variability in the data. Structural differences were observed between biofilms on the high-shear baffle side of the reactor compared to the lower shear glass side of the reactor. Further studies are required to determine whether biofilm susceptibility to antimicrobials differs based on structural differences attributed to orientation.Item Diversity and evolution of nitric oxide reduction in bacteria and archaea(Proceedings of the National Academy of Sciences, 2024-06) Murali, Ranjani; Pace, Laura A.; Sanford, Robert A.; Ward, L. M.; Lynes, Mackenzie M.; Hatzenpichler, Roland; Lingappa, Usha F.; Fischer, Woodward W.; Gennis, Robert B.; Hemp, JamesWith the advent of culture-independent techniques for studying environmental microbes, our knowledge of their diversity has exploded, uncovering unique organisms, pathways, and proteins carrying out important processes in the biosphere. Novel biochemical reactions are often proposed based on sequence data, but experimental validation is difficult and rare. In this work, we used environmental sequence data to find enzymes that produce the greenhouse gas N2O from NO and validated our hypothesis with experiments. These new enzymes likely contribute to global N2O fluxes and expand the breadth of nitrogen cycling. We also demonstrated that these enzymes evolved multiple times from oxygen reductases, indicating that the evolutionary histories of aerobic respiration and denitrification—and more broadly the oxygen and nitrogen cycles—are tightly connected.Item Beyond the Surface: Non-Invasive Low-Field NMR Analysis of Microbially-Induced Calcium Carbonate Precipitation in Shale Fractures(Springer Science and Business Media LLC, 2024-07) Willet, Matthew R.; Bedey, Kayla; Crandall, Dustin; Seymour, Joseph D.; Rutqvist, Jonny; Cunningham, Alfred B.; Phillips, Adrienne J.; Kirkland, Catherine M.Microbially-induced calcium carbonate precipitation (MICP) is a biological process in which microbially-produced urease enzymes convert urea and calcium into solid calcium carbonate (CaCO3) deposits. MICP has been demonstrated to reduce permeability in shale fractures under elevated pressures, raising the possibility of applying this technology to enhance shale reservoir storage safety. For this and other applications to become a reality, non-invasive tools are needed to determine how effectively MICP seals shale fractures at subsurface temperatures. In this study, two different MICP strategies were tested on 2.54 cm diameter and 5.08 cm long shale cores with a single fracture at 60 ℃. Flow-through, pulsed-flow MICP-treatment was repeatedly applied to Marcellus shale fractures with and without sand (“proppant”) until reaching approximately four orders of magnitude reduction in apparent permeability, while a single application of polymer-based “immersion” MICP-treatment was applied to an Eagle Ford shale fracture with proppant. Low-field nuclear magnetic resonance (LF-NMR) and X-Ray computed microtomography (micro-CT) techniques were used to assess the degree of biomineralization. With the flow-through approach, these tools revealed that while CaCO3 precipitation occurred throughout the fracture, there was preferential precipitation around proppant. Without proppant, the same approach led to premature sealing at the inlet side of the core. In contrast, immersion MICP-treatment sealed off the fracture edges and showed less mineral precipitation overall. This study highlights the use of LF-NMR relaxometry in characterizing fracture sealing and can help guide NMR logging tools in subsurface remediation efforts.Item Aging alters the subchondral bone response 7 days after noninvasive traumatic joint injury in C57BL/6JN mice(Wiley, 2024) Dauenhauer, Lexia A.; Hislop, Brady D.; Brahmachary, Priyanka; Devine, Connor; Gibbs, Dustin; June, Ronald K.; Heveran, Chelsea M.Posttraumatic osteoarthritis (PTOA) commonly develops following anterior cruciate ligament (ACL) injuries, affecting around 50% of individuals within 10–20 years. Recent studies have highlighted early changes in subchondral bone structure after ACL injury in adolescent or young adult mice, which could contribute to the development of PTOA. However, ACL injuries do not only occur early in life. Middle-aged and older patients also experience ACL injuries and PTOA, but whether the aged subchondral bone also responds rapidly to injury is unknown. This study utilized a noninvasive, single overload mouse injury model to assess subchondral bone microarchitecture, turnover, and material properties in both young adults (5 months) and early old age (22 months) female C57BL/6JN mice at 7 days after injury. Mice underwent either joint injury (i.e., produces ACL tears) or sham injury procedures on both the loaded and contralateral limbs, allowing evaluation of the impacts of injury versus loading. The subchondral bone response to ACL injury is distinct for young adult and aged mice. While 5-month mice show subchondral bone loss and increased bone resorption postinjury, 22-month mice did not show loss of bone structure and had lower bone resorption. Subchondral bone plate modulus increased with age, but not with injury. Both ages of mice showed several bone measures were altered in the contralateral limb, demonstrating the systemic skeletal response to joint injury. These data motivate further investigation to discern how osteochondral tissues differently respond to injury in aging, such that diagnostics and treatments can be refined for these demographics.Item Ecology of Legionella pneumophila biofilms: The link between transcriptional activity and the biphasic cycle(Elsevier BV, 2024-06) Barbosa, Ana; Azevedo, Nuno F.; Goeres, Darla M.; Cerqueira, LauraThere has been considerable discussion regarding the environmental life cycle of Legionella pneumophila and its virulence potential in natural and man-made water systems. On the other hand, the bacterium's morphogenetic mechanisms within host cells (amoeba and macrophages) have been well documented and are linked to its ability to transition from a non-virulent, replicative state to an infectious, transmissive state. Although the morphogenetic mechanisms associated with the formation and detachment of the L. pneumophila biofilm have also been described, the capacity of the bacteria to multiply extracellularly is not generally accepted. However, several studies have shown genetic pathways within the biofilm that resemble intracellular mechanisms. Understanding the functionality of L. pneumophila cells within a biofilm is fundamental for assessing the ecology and evaluating how the biofilm architecture influences L. pneumophila survival and persistence in water systems. This manuscript provides an overview of the biphasic cycle of L. pneumophila and its implications in associated intracellular mechanisms in amoeba. It also examines the molecular pathways and gene regulation involved in L. pneumophila biofilm formation and dissemination. A holistic analysis of the transcriptional activities in L. pneumophila biofilms is provided, combining the information of intracellular mechanisms in a comprehensive outline. Furthermore, this review discusses the techniques that can be used to study the morphogenetic states of the bacteria within biofilms, at the single cell and population levels.