Scholarly Work - Center for Biofilm Engineering
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Item A Novel Irrigant to Eliminate Planktonic Bacteria and Eradicate Biofilm Superstructure With Persistent Effect During Total Hip Arthroplasty(Elsevier BV, 2022-02) Bashyal, Ravi K.; Mathew, Matt; Bowen, Edward; James, Garth A.; Stulberg, S. DavidBackground Numerous studies have examined the use of topical and irrigation-related adjuvants to decrease the risk of periprosthetic joint infection (PJI) after total hip arthroplasty. Many issues related to their use remain to be investigated. These include cost, antibiotic stewardship, bactericidal effect on planktonic bacteria, host cytotoxicity, necessity to irrigate/dilute potentially cytotoxic agents after their application, and impact on biofilm. Methods Bacterial strains of microorganisms were grown in optimal medium. After the growth phase, the organisms were exposed to the novel irrigation solution (XPerience) or phosphate buffer solution (PBS) for 5 minutes before a neutralizing broth was added. The colony-forming units per milliliter and the log reduction in colony-forming units in the treated sample vs the control were then determined. Subsequently, biofilms of microorganisms were grown on hydroxyapatite-coated glass slides. Each slide was then exposed to irrigation solutions for various contact times. Biofilm quantification was performed and the log10 density of each organism was obtained. Results In vitro testing of the irrigant demonstrated 6-log reductions in planktonic bacteria in 5 minutes, and 4-log to 8-log reductions in biofilms. Laboratory tissue testing has demonstrated minimal cytotoxic effects to host tissue allowing for solution to remain in contact with the host without need for subsequent irrigation, creating a barrier to biofilm for up to 5 hours after its application. Conclusion This novel irrigant demonstrates high efficacy against both planktonic bacteria and bacterial biofilms in laboratory testing. Large series in vivo data are necessary to further establish its efficacy in reducing primary and recurrent surgical site infections.Item Zosteric acid and salicylic acid bound to a low density polyethylene surface successfully control bacterial biofilm formation(2018-04) Catto, C.; James, Garth A.; Villa, Federica; Villa, S.; Cappitelli, FrancescaThe active moieties of the anti-biofilm natural compounds zosteric (ZA) and salicylic (SA) acids have been covalently immobilized on a low density polyethylene (LDPE) surface. The grafting procedure provided new non-toxic eco-friendly materials (LDPE-CA and LDPE-SA) with anti-biofilm properties superior to the conventional biocide-based approaches and with features suitable for applications in challenging fields where the use of antimicrobial agents is limited. Microbiological investigation proved that LDPE-CA and LDPE-SA: (1) reduced Escherichia coli biofilm biomass by up to 61% with a mechanism that did not affect bacterial viability; (2) significantly affected biofilm morphology, decreasing biofilm thickness, roughness, substratum coverage, cell and matrix polysaccharide bio-volumes by >80% and increasing the surface to bio-volume ratio; (3) made the biofilm more susceptible to ampicillin and ethanol. Since no molecules were leached from the surface, they remained constantly effective and below the lethal level; therefore, the risk of inducing resistance was minimized.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.