Center for Biofilm Engineering (CBE)
Permanent URI for this communityhttps://scholarworks.montana.edu/handle/1/9334
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 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 Bacterial transfer and biofilm formation in needleless connectors in a clinically simulated in vitro catheter model(Cambridge University Press, 2023-04) Ryder, Marcia; deLancey-Pulcini, Elinor; Parker, Albert E.; James, Garth A.Objective: Although needleless connectors (NCs) are widely used in clinical practice, they carry significant risk of bloodstream infection (BSI). In this study, we quantified differences in bacterial transfer and biofilm formation between various NCs. Design: Prospective, clinically simulated in vitro experimental study. Methods: We tested 20 NCs in a 5-day clinical simulation of Staphylococcus aureus inoculations onto NC septum surfaces, which were then flushed with saline and cultured for bacterial transfer. Biofilm formation was measured through destructive sampling of the connector-catheter system. Moreover, 8 NC design factors were evaluated for their influence on bacterial transfer and biofilm formation. This study was designed without a disinfection protocol to ascertain the intrinsic risk of each NC. Results: Clave Neutron and MicroClave had the lowest overall mean log density of bacteria in the flush compared to other NCs (P < .05), except there were no statistically significant differences between Clave Neutron, Microclave, SafeTouch, and SafeAccess (P ≥ .05). The amount of biofilm in the NC was positively associated with bacteria in the flush (P < .0005). Among 8 design factors, flow path was most important, with the internal cannula associated with a statistically significant 1 log reduction (LR) in bacteria in the flush (R2 = 49%) and 0.5–2 LR in the connector (R2 = 34%). All factors together best explained bacteria in the flush (R2 = 65%) and biofilm in the connector (R2 = 48%). Conclusions: Bacterial transfer and biofilm formation in the connector-catheter system varied statistically significantly between the 20 NCs, suggesting that NC choice can lower the risk of developing catheter-related BSIs.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 Efficacy of Common Antiseptic Solutions Against Clinically Relevant Planktonic Microorganisms(SLACK, Inc., 2022-03) O'Donnell, Jeffrey A.; Wu, Mark; Cochrane, Niall H.; Belay, Elshaday; Myntti, Matthew F.; James, Garth A.; Ryan, Sean P.; Seyler, Thorsten M.Prosthetic joint infections (PJIs) are among the most devastating complications after joint replacement. There is limited evidence regarding the efficacy of different antiseptic solutions in reducing planktonic microorganism burden. The purpose of this study was to test the efficacy of different antiseptic solutions against clinically relevant planktonic microorganisms. We designed an experiment examining the efficacy of several antiseptic solutions against clinically relevant planktonic microorganisms in vitro. Regarding planktonic microorganisms, povidone-iodine had 99.9% or greater reduction for all microorganisms tested except for methicillin-resistant Staphylococcus aureus, which was reduced by 60.44%. Irrisept (Irrimax Corp) had 99.9% or greater reduction for all microorganisms except Staphylococcus epidermidis (98.31%) and Enterococcus faecalis (48.61%). Bactisure (Zimmer Surgical Inc) had 99.9% or greater reduction for all microorganisms tested. Various measures exist for PJI prevention, one of which is intraoperative irrigation. We tested irrigants against clinically relevant planktonic microorganisms in vitro and found significant differences in efficacy among them. Further clinical outcome data are necessary to determine whether these solutions can impact PJI in vivo. [Orthopedics. 2022;45(2):122–127.]Item Search for a Shared Genetic or Biochemical Basis for Biofilm Tolerance to Antibiotics across Bacterial Species(American Society for Microbiology, 2022-04) Stewart, Philip S.; Williamson, Kerry S.; Boegli, Laura; Hamerly, Timothy; White, Ben; Scott, Liam; Hu, Xiao; Mumey, Brendan M.; Franklin, Michael J.; Bothner, Brian; Vital-Lopez, Francisco G.; Wallqvist, Anders; James, Garth A.Is there a universal genetically programmed defense providing tolerance to antibiotics when bacteria grow as biofilms? A comparison between biofilms of three different bacterial species by transcriptomic and metabolomic approaches uncovered no evidence of one. Single-species biofilms of three bacterial species (Pseudomonas aeruginosa, Staphylococcus aureus, and Acinetobacter baumannii) were grown in vitro for 3 days and then challenged with respective antibiotics (ciprofloxacin, daptomycin, and tigecycline) for an additional 24 h. All three microorganisms displayed reduced susceptibility in biofilms compared to planktonic cultures. Global transcriptomic profiling of gene expression comparing biofilm to planktonic and antibiotic-treated biofilm to untreated biofilm was performed. Extracellular metabolites were measured to characterize the utilization of carbon sources between biofilms, treated biofilms, and planktonic cells. While all three bacteria exhibited a species-specific signature of stationary phase, no conserved gene, gene set, or common functional pathway could be identified that changed consistently across the three microorganisms. Across the three species, glucose consumption was increased in biofilms compared to planktonic cells, and alanine and aspartic acid utilization were decreased in biofilms compared to planktonic cells. The reasons for these changes were not readily apparent in the transcriptomes. No common shift in the utilization pattern of carbon sources was discerned when comparing untreated to antibiotic-exposed biofilms. Overall, our measurements do not support the existence of a common genetic or biochemical basis for biofilm tolerance against antibiotics. Rather, there are likely myriad genes, proteins, and metabolic pathways that influence the physiological state of individual microorganisms in biofilms and contribute to antibiotic tolerance.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.