Publications by Colleges and Departments (MSU - Bozeman)
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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 Anti-Biofilm Efficacy of Commonly Used Wound Care Products in In Vitro Settings(MDPI AG, 2023-03) Regulski, Matthew; Myntti, Matthew F.; James, Garth A.Considering the prevalence and pathogenicity of biofilms in wounds, this study was designed to evaluate the anti-biofilm capabilities of eight commercially available wound care products using established in vitro assays for biofilms. The products evaluated included dressings with multiple delivery formats for ionic silver including nanocrystalline, gelling fibers, polyurethane (PU) foam, and polymer matrix. Additionally, non-silver-based products including an extracellular polymeric substance (EPS)-dissolving antimicrobial wound gel (BDWG), a collagenase-based debriding ointment and a fish skin-based skin substitute were also evaluated. The products were evaluated on Staphylococcus aureus and Pseudomonas aeruginosa mixed-species biofilms grown using colony drip flow reactor (CDFR) and standard drip flow reactor (DFR) methodologies. Anti-biofilm efficacy was measured by viable plate counts and confocal scanning laser microscopy (CSLM). Four of the eight wound care products tested were efficacious in inhibiting growth of new biofilm when compared with untreated controls. These four products were further evaluated against mature biofilms. BDWG was the only product that achieved greater than 2-log growth reduction (5.88 and 6.58 for S. aureus and P. aeruginosa, respectively) of a mature biofilm. Evaluating both biofilm prevention and mature biofilm disruption capacity is important to a comprehensive understanding of the anti-biofilm efficacy of wound care products.Item Antimicrobial effects of an acidified nitrite foam on drip flow reactor biofilm(European Wound Management Association, 2024-04) Miller, C. Michael; James, Garth; Bell, David; Schultz, GregBackground. Nitric oxide (NO) plays critical roles in wound healing, including stimulating vasodilation, angiogenesis and broad antimicrobial activity. Aim. To measure the effect of an acidified nitrite foam (ANF) on biofilms created by six different microbes. Methods. A novel method of generating, delivering and topically applying NO gas at the point of care was developed using ANF in a mixed bubble foam and was tested in vitro against six common microbial wound pathogens. Results. A single 5-minute topical exposure of the NO bubble gas formulation generated a 5.8-log10 reduction of mature biofilm of Pseudomonas aeruginosa, a 5.1-log10 reduction of Staphylococcus aureus biofilm, a 4.0-log10 reduction of Staphylococcus epidermidis biofilm, a 3.2-log10 reduction of Proteus mirabilis biofilm, a 2.7-log10 reduction of Acinetobacter baumannii biofilm, and a 1.5-log10 reduction of Candida albicans biofilm. Conclusion. The efficacy of a 5-minute treatment of ANF used on biofilms of P. aeruginosa, A. baumannii, S. aureus, C. albicans, P. mirabilis and S. epidermidis was confirmed. The treatment resulted in a significant reduction in colony-forming units per square centimetre (CFU/cm2) comparable to or surpassing other methods of NO gas application, suggesting NO containing foam’s utility as a point of care solution for chronic wounds with elevated bioburden and biofilms where levels of endogenously produced NO may be insufficient for wound healing completion.Item Critical analysis of methods to determine growth, control and analysis of biofilms for potential non-submerged antibiofilm surfaces and coatings(Elsevier BV, 2024-06) Redfern, J.; Cunliffe, A. J.; Goeres, D. M.; Azevedo, N. F.; Verran, J.The potential uses for antibiofilm surfaces reach across different sectors with significant resultant economic, societal and health impact. For those interested in using antibiofilm surfaces in the built environment, it is important that efficacy testing methods are relevant, reproducible and standardised where possible, to ensure data outputs are applicable to end-use, and comparable across the literature. Using pre-defined keywords, a review of literature reporting on antimicrobial surfaces (78 articles), within which a potential application was described as non-submerged/non-medical surface or coating with antibiofilm action, was undertaken. The most used methods utilized the growth of biofilm in submerged and static systems. Quantification varied (from most to least commonly used) across colony forming unit counts, non-microscopy fluorescence or spectroscopy, microscopy analysis, direct agar-contact, sequencing, and ELISA. Selection of growth media, microbial species, and incubation temperature also varied. In many cases, definitions of biofilm and attempts to quantify antibiofilm activity were absent or vague. Assessing a surface after biofilm recovery or assessing potential regrowth of a biofilm after initial analysis was almost entirely absent. It is clear the field would benefit from widely agreed and adopted approaches or guidance on how to select and incorporate end-use specific conditions, alongside minimum reporting guidelines may benefit the literature.