Center for Biofilm Engineering (CBE)
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At the Center for Biofilm Engineering (CBE), multidisciplinary research teams develop beneficial uses for microbial biofilms and find solutions to industrially relevant biofilm problems. The CBE was established at Montana State University, Bozeman, in 1990 as a National Science Foundation Engineering Research Center. As part of the MSU College of Engineering, the CBE gives students a chance to get a head start on their careers by working on research teams led by world-recognized leaders in the biofilm field.
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Item Analysis of Clostridium difficile biofilms: imaging and antimicrobial treatment(2018-01) James, Garth A.; Chesnel, L.; Boegli, Laura; Pulcini, Elinor D.; Fisher, Steve T.; Stewart, Philip S.BACKGROUND: Clostridium difficile, a spore-forming Gram-positive anaerobic bacillus, is the most common causative agent of healthcare-associated diarrhoea. Formation of biofilms may protect C. difficile against antibiotics, potentially leading to treatment failure. Furthermore, bacterial spores or vegetative cells may linger in biofilms in the gut causing C. difficile infection recurrence. OBJECTIVES: In this study, we evaluated and compared the efficacy of four antibiotics (fidaxomicin, surotomycin, vancomycin and metronidazole) in penetrating C. difficile biofilms and killing vegetative cells. METHODS: C. difficile biofilms grown initially for 48 or 72 h using the colony biofilm model were then treated with antibiotics at a concentration of 25 × MIC for 24 h. Vegetative cells and spores were enumerated. The effect of treatment on biofilm structure was studied by scanning electron microscopy (SEM). The ability of fidaxomicin and surotomycin to penetrate biofilms was studied using fluorescently tagged antibiotics. RESULTS: Both surotomycin and fidaxomicin were significantly more effective than vancomycin or metronidazole (P < 0.001) at killing vegetative cells in established biofilms. Fidaxomicin was more effective than metronidazole at reducing viable spore counts in biofilms (P < 0.05). Fluorescently labelled surotomycin and fidaxomicin penetrated C. difficile biofilms in < 1 h. After 24 h of treatment, SEM demonstrated that both fidaxomicin and surotomycin disrupted the biofilm structure, while metronidazole had no observable effect. CONCLUSIONS: Fidaxomicin is effective in disrupting C. difficile biofilms, killing vegetative cells and decreasing spore counts.Item Detection of Pseudomonas aeruginosa biomarkers from thermally injured mice in situ using imaging mass spectrometry(2017-12) Hamerly, Timothy; Everett, Jake A.; Paris, Nina; Fisher, Steve T.; Karunamurthy, Arivarasan; James, Garth A.; Rumbaugh, Kendra P.; Rhoads, Daniel D.; Bothner, BrianMonitoring patients with burn wounds for infection is standard practice because failure to rapidly and specifically identify a pathogen can result in poor clinical outcomes, including death. Therefore, a method that facilitates detection and identification of pathogens in situ within minutes of biopsy would be a significant benefit to clinicians. Mass spectrometry is rapidly becoming a standard tool in clinical settings, capable of identifying specific pathogens from complex samples. Imaging mass spectrometry (IMS) expands the information content by enabling spatial resolution of biomarkers in tissue samples as in histology, without the need for specific stains/antibodies. Herein, a murine model of thermal injury was used to study infection of burn tissue by Pseudomonas aeruginosa. This is the first use of IMS to detect P. aeruginosa infection in situ from thermally injured tissue. Multiple molecular features could be spatially resolved to infected or uninfected tissue. This demonstrates the potential use of IMS in a clinical setting to aid doctors in identifying both presence and species of pathogens in tissue.Item Effects of ultrasonic treatment on the efficacy of gentamicin against established pseudomonas aeruginosa biofilms(1996-05) Huang, Ching-Tsan; James, Garth A.; Pitt, William G.; Stewart, Philip S.The effect of simultaneous ultrasonic treatment on the efficacy of gentamicin against planktonic and established biofilm cells of Pseudomonas aeruginosa was investigated. Planktonic cells were treated with 6 or 12 μg ml−1 of gentamicin for 4 h with ultrasonic treatment at three levels of power density (0.2, 2 and 15 mW cm−2). Biofilm cells grown on stainless steel slides in a continuous flow reactor were treated with 30 μg ml−1 of gentamicin and ultrasound. Ultrasound itself at these power levels did not cause cell killing or lysis in planktonic and biofilm cultures. Concentrations of 6 and 12 mg ml−1 gentamicin led to 2.65- and 2.75-log reductions of the surviving fraction in planktonic cultures in the absence of ultrasound. The addition of ultrasound did not show further reduction compared with those without ultrasonication. Gentamicin (30 μg ml−1) caused variable killing in biofilms which ranged from 0.83- to 2.86-log reductions of the surviving fraction without ultrasonication. Gentamicin efficacy measured by the surviving fraction was improved by 0.28-, 1.12- and 0.58-log when coupled with 0.2, 2 and 15 mW cm−2 ultrasonic treatments, respectively. Experimental results indicated that ultrasound modestly improved the efficacy of gentamicin against established P. aeruginosa biofilms.Item Interspecies bacterial interactions in biofilms(1995-10) James, Garth A.; Beaudette, L.; Costerton, J. WilliamInteractions among bacterial populations can have a profound influence on the structure and physiology of microbial communities. Interspecies microbial interactions begin to influence a biofilm during the initial stages of formation, bacterial attachment and surface colonization, and continue to influence the structure and physiology of the biofilm as it develops. Although the majority of research on bacterial interactions has utilized planktonic communities, the characteristics of biofilm growth (cell positions that are relatively stable and local areas of hindered diffusion) suggest that interspecies interactions may be more significant in biofilms.Item Digital image analysis of growth and starvation responses of a surface-colonizing acinetobacter sp.(1995-02) James, Garth A.; Korber, D. R.; Caldwell, D. E.; Costerton, J. WilliamSurface growth of an Acinetobacter sp. cultivated under several nutrient regimens was examined by using continuous-flow slide culture, phase-contrast microscopy, scanning confocal laser microscopy, and computer image analysis. Irrigation of attached coccoid stationary-phase Acinetobacter sp. cells with high-nutrient medium resulted in a transition from coccoid to bacillar morphology. Digital image analysis revealed that this transition was biphasic. During phase I, both the length and the width of cells increased. In contrast, cell width remained constant during phase II, while both cell length and cell area increased at a rate greater than in phase I. Cells were capable of growth and division without morphological transition when irrigated with a low-nutrient medium. Rod-shaped cells reverted to cocci by reduction-division when irrigated with starvation medium. This resulted in conservation of cell area (biomass) with an increase in cell number. In addition, the changes in cell morphology were accompanied by changes in the stability of cell attachment. During phase I, coccoid cells remained firmly attached. Following transition in high-nutrient medium, bacillar cells displayed detachment, transient attachment, and drifting behaviors, resulting in a spreading colonization pattern. In contrast, cells irrigated with a low-nutrient medium remained firmly attached to the surface and eventually formed tightly packed microcolonies. It is hypothesized that the coccoid and bacillar Acinetobacter sp. morphotypes and associated behavior represent specialized physiological adaptations for attachment and colonization in low-nutrient systems (coccoid morphotype) or dispersion under high-nutrient conditions (bacillar morphotype).Item Consensus guidelines for the identification and treatment of biofilms in chronic nonhealing wounds(2017-09) Schultz, Gregory; Bjarnsholt, Thomas; James, Garth A.; Leaper, David; McBain, Andrew J.; Malone, Matthew; Stoodley, Paul; Swanson, Terry; Tachi, Masahiro; Wolcott, Randall D.Background: Despite a growing consensus that biofilms contribute to a delay in the healing of chronic wounds, conflicting evidence pertaining to their identification and management can lead to uncertainty regarding treatment. This, in part, has been driven by reliance on in vitro data or animal models, which may not directly correlate to clinical evidence on the importance of biofilms. Limited data presented in human studies have further contributed to the uncertainty. Guidelines for care of chronic wounds with a focus on biofilms are needed to help aid the identification and management of biofilms, providing a clinical focus to support clinicians in improving patient care through evidence-based medicine. Methods: A Global Wound Biofilm Expert Panel, comprising 10 clinicians and researchers with expertise in laboratory and clinical aspects of biofilms, was identified and convened. A modified Delphi process, based on published scientific data and expert opinion, was used to develop consensus statements that could help identify and treat biofilms as part of the management of chronic nonhealing wounds. Using an electronic survey, panel members rated their agreement with statements about biofilm identification and treatment, and the management of chronic nonhealing wounds. Final consensus statements were agreed on in a face-to-face meeting. Results: Participants reached consensus on 61 statements in the following topic areas: understanding biofilms and the problems they cause clinicians; current diagnostic options; clinical indicators of biofilms; future options for diagnostic tests; treatment strategies; mechanical debridement; topical antiseptics; screening antibiofilm agents; and levels of evidence when choosing antibiofilm treatments. Conclusion: This consensus document attempts to clarify misunderstandings about the role of biofilms in clinical practice, and provides a basis for clinicians to recognize biofilms in chronic nonhealing wounds and manage patients optimally. A new paradigm for wound care, based on a stepped-down treatment approach, was derived from the consensus statements.Item Minireview: Biofilms, the customized microniche(1994-04) Costerton, J. William; Lewandowski, Zbigniew; de Beer, Dirk; Caldwell, D. E.; Korber, D. R.; James, Garth A.Item Microbial barriers to the spread of pollution(2000) James, Garth A.; Warwood, B. K.; Hiebert, Dwight Randall; Cunningham, Alfred B.Contamination of groundwater with toxic and carcinogenic compounds is a serious concern for public health and environmental quality. This problem is commonly manifested as a contaminant plume migrating in the direction of groundwater flow from a point source. Containment of the contaminant plume is important for preventing further migration and localizing the plume for in situ or ex situ remediation. Current containment methods include sheet pilings and grout curtains. These abiotic barriers require extensive physical manipulation of the site (e.g. excavation and back-filling) and are expensive to construct. An alternative approach, biobarrier technology, involves the use of microbial biomass produced in situ to manipulate groundwater flow (Figure 1). Biobarriers promise to be more cost effective and cause less surface disruption then conventional barrier technologies. Furthermore, containment using biobarriers can be combined with in situ biodegradation or biosequestration. This chapter will review published research that relates to biobarrier formation and present results from a mesocosm test of biobarrier longevity. These results demonstrate the effectiveness of microbial barriers for manipulation of hydraulics in mesoscale porous medium reactors.Item Biofilm process in porous media - practical applications(1997) Cunningham, Alfred B.; Warwood, B. K.; Sturman, Paul J.; Horrigan, K.; James, Garth A.; Costerton, J. William; Hiebert, Dwight RandallItem Subsurface biofilm barriers for the containment and remediation of contaminated groundwater(2003-07) Cunningham, Alfred B.; Sharp, Robert R.; Hiebert, Dwight Randall; James, Garth A.An engineered microbial biofilm barrier capable of reducing aquifer hydraulic conductivity while simultaneously biodegrading nitrate has been developed and tested at a field-relevant scale. The 22-month demonstration project was conducted at the MSE Technology Applications Inc. test facility in Butte, Montana, which consisted of a 130 ft wide, 180 ft long, 21 ft deep, polyvinylchloride (PVC)-lined test cell, with an initial hydraulic conductivity of 4.2 x 10-2 cm/s. A flow field was established across the test cell by injecting water up-gradient while simultaneously pumping from an effluent well located approximately 82 ft down gradient. A 30 ft wide biofilm barrier was developed along the centerline of the test cell by injecting a starved bacterial inoculum of Pseudomonas fluorescens strain CPC211a, followed by injection of a growth nutrient mixture composed of molasses, nitrate, and other additives. A 99% reduction of average hydraulic conductivity across the barrier was accomplished after three months of weekly or bi-weekly injections at intervals ranging from three to ten months. After the barrier was in place, a sustained concentration of 100 mg/l nitrate nitrogen, along with a 100 mg/l concentration of conservative (chloride) tracer, was added to the test cell influent over a six-month period. At the test cell effluent the concentration of chloride increased to about 80 mg/l while the effluent nitrate concentration varied between 0.0 and 6.4mg/l.