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Barbosa A, Azevedo NF, Goeres DM, Cerqueira L. Ecology of Legionella pneumophila biofilms: The link between transcriptional activity and the biphasic cycle. Biofilm 2024; 7:100196. [PMID: 38601816 PMCID: PMC11004079 DOI: 10.1016/j.bioflm.2024.100196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 03/10/2024] [Accepted: 03/29/2024] [Indexed: 04/12/2024] Open
Abstract
There 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.
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Affiliation(s)
- Ana Barbosa
- LEPABE – Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
- ALiCE – Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
| | - Nuno F. Azevedo
- LEPABE – Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
- ALiCE – Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
| | - Darla M. Goeres
- LEPABE – Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
- ALiCE – Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
- The Center for Biofilm Engineering, Montana State University, Bozeman, MT, USA
| | - Laura Cerqueira
- LEPABE – Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
- ALiCE – Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
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2
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Miller LA, Buckingham-Meyer K, Goeres DM. Simulated aging of draught beer line tubing increases biofilm contamination. Int J Food Microbiol 2024; 415:110630. [PMID: 38401380 DOI: 10.1016/j.ijfoodmicro.2024.110630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 02/13/2024] [Accepted: 02/15/2024] [Indexed: 02/26/2024]
Abstract
Craft brewing is continually gaining popularity in the United States. Craft brewers are committed to producing a wide variety of products and have a vested interest in product quality. Therefore, these brewers have the expectation that the beer poured at the tap will match the quality product that left the brewery. The presence of biofilm in draught lines is hypothesized as a contributing factor when this expectation is not achieved. Clean in place strategies based on the Sinner's Circle of Cleaning are used to remediate organic and inorganic accumulation in beer draught lines, including controlling biofilm accumulation. A study was conducted to determine if repeated exposure to chemical cleaning of vinyl beer tubing impacted biofilm growth, kill/removal, and subsequent regrowth of a mixed species biofilm. The tubing was conditioned to simulate one, two, and five years of use. The data collected demonstrates a clear trend between simulated age of the tubing and biofilm accumulation on the surface. Bacterial log densities ranged from 5.6 Log10(CFU/cm2) for the new tubing to 6.6 Log10(CFU/cm2) for tubing aged to simulate five years of use. The counts for the yeast were similar. Caustic cleaning of the tubing, regardless of starting biofilm coverage, left less than 2.75 Log10(CFU/cm2) viable bacteria and yeast cells remaining on the tubing surface. This demonstrated the effectiveness of the caustic at controlling biofilm accumulation in the simulated beer draught line. The biofilm that accumulated in the five-year aged tubing was able to recover more quickly, reaching 3.6 Log10(CFU/cm2) within 24 h indicating the treatment did not fully eradicate the biofilm, suggesting that the strong chemistry used in this study would cease to be as effective over time.
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Affiliation(s)
- Lindsey A Miller
- Center for Biofilm Engineering, Montana State University, 366 Barnard Hall, Bozeman, MT 59717, United States of America
| | - Kelli Buckingham-Meyer
- Center for Biofilm Engineering, Montana State University, 366 Barnard Hall, Bozeman, MT 59717, United States of America
| | - Darla M Goeres
- Center for Biofilm Engineering, Montana State University, 366 Barnard Hall, Bozeman, MT 59717, United States of America.
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3
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Affiliation(s)
- Darla M. Goeres
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, 59717, USA
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Ausbacher D, Miller LA, Goeres DM, Stewart PS, Strøm MB, Fallarero A. α,α-disubstituted β-amino amides eliminate Staphylococcus aureus biofilms by membrane disruption and biomass removal. Biofilm 2023; 6:100151. [PMID: 37662850 PMCID: PMC10474319 DOI: 10.1016/j.bioflm.2023.100151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Revised: 08/12/2023] [Accepted: 08/24/2023] [Indexed: 09/05/2023] Open
Abstract
Bacterial biofilms account for up to 80% of all infections and complicate successful therapies due to their intrinsic tolerance to antibiotics. Biofilms also cause serious problems in the industrial sectors, for instance due to the deterioration of metals or microbial contamination of products. Efforts are put in finding novel strategies in both avoiding and fighting biofilms. Biofilm control is achieved by killing and/or removing biofilm or preventing transition to the biofilm lifestyle. Previous research reported on the anti-biofilm potency of α,α-disubstituted β-amino amides A1, A2 and A3, which are small antimicrobial peptidomimetics with a molecular weight below 500 Da. In the current study it was investigated if these derivatives cause a fast disintegration of biofilm bacteria and removal of Staphylococcus aureus biofilms. One hour incubation of biofilms with all three derivatives resulted in reduced metabolic activity and membrane permeabilization in S. aureus (ATCC 25923) biofilms. Bactericidal properties of these derivatives were attributed to a direct effect on membranes of biofilm bacteria. The green fluorescence protein expressing Staphylococcus aureus strain AH2547 was cultivated in a CDC biofilm reactor and utilized for disinfectant efficacy testing of A3, following the single tube method (American Society for Testing and Materials designation number E2871). A3 at a concentration of 90 μM acted as fast as 100 μM chlorhexidine and was equally effective. Confocal laser scanning microscopy studies showed that chlorhexidine treatment lead to fluorescence fading indicating membrane permeabilization but did not cause biomass removal. In contrast, A3 treatment caused a simultaneous biofilm fluorescence loss and biomass removal. These dual anti-biofilm properties make α,α-disubstituted β-amino amides promising scaffolds in finding new control strategies against recalcitrant biofilms.
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Affiliation(s)
- Dominik Ausbacher
- Natural Products and Medicinal Chemistry Research Group, Department of Pharmacy, UiT The Arctic University of Norway, N-9037, Tromsø, Norway
| | - Lindsey A. Miller
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, 59717, USA
| | - Darla M. Goeres
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, 59717, USA
| | - Philip S. Stewart
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, 59717, USA
| | - Morten B. Strøm
- Natural Products and Medicinal Chemistry Research Group, Department of Pharmacy, UiT The Arctic University of Norway, N-9037, Tromsø, Norway
| | - Adyary Fallarero
- Drug Research Program, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, FI-00014, Helsinki, Finland
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Vélez Justiniano YA, Goeres DM, Sandvik EL, Kjellerup BV, Sysoeva TA, Harris JS, Warnat S, McGlennen M, Foreman CM, Yang J, Li W, Cassilly CD, Lott K, HerrNeckar LE. Mitigation and use of biofilms in space for the benefit of human space exploration. Biofilm 2023; 5:100102. [PMID: 36660363 PMCID: PMC9843197 DOI: 10.1016/j.bioflm.2022.100102] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/21/2022] [Accepted: 12/22/2022] [Indexed: 01/08/2023] Open
Abstract
Biofilms are self-organized communities of microorganisms that are encased in an extracellular polymeric matrix and often found attached to surfaces. Biofilms are widely present on Earth, often found in diverse and sometimes extreme environments. These microbial communities have been described as recalcitrant or protective when facing adversity and environmental exposures. On the International Space Station, biofilms were found in human-inhabited environments on a multitude of hardware surfaces. Moreover, studies have identified phenotypic and genetic changes in the microorganisms under microgravity conditions including changes in microbe surface colonization and pathogenicity traits. Lack of consistent research in microgravity-grown biofilms can lead to deficient understanding of altered microbial behavior in space. This could subsequently create problems in engineered systems or negatively impact human health on crewed spaceflights. It is especially relevant to long-term and remote space missions that will lack resupply and service. Conversely, biofilms are also known to benefit plant growth and are essential for human health (i.e., gut microbiome). Eventually, biofilms may be used to supply metabolic pathways that produce organic and inorganic components useful to sustaining life on celestial bodies beyond Earth. This article will explore what is currently known about biofilms in space and will identify gaps in the aerospace industry's knowledge that should be filled in order to mitigate or to leverage biofilms to the advantage of spaceflight.
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Affiliation(s)
- Yo-Ann Vélez Justiniano
- ECLSS Development Branch, NASA Marshall Space Flight Center, Huntsville, AL, USA,Corresponding author.
| | - Darla M. Goeres
- The Center for Biofilm Engineering, Montana State University, Bozeman, MT, USA,Chemical and Biological Engineering, Montana State University, Bozeman, MT, USA
| | | | - Birthe Veno Kjellerup
- Department of Civil and Environmental Engineering, University of Maryland, College Park, MD, USA
| | - Tatyana A. Sysoeva
- Department of Biological Sciences, The University of Alabama in Huntsville, Huntsville, AL, USA
| | - Jacob S. Harris
- Biomedical and Environmental Science Division, NASA Johnson Space Center, Houston, TX, USA
| | - Stephan Warnat
- The Center for Biofilm Engineering, Montana State University, Bozeman, MT, USA,Mechanical Engineering, Montana State University, Bozeman, MT, USA
| | - Matthew McGlennen
- The Center for Biofilm Engineering, Montana State University, Bozeman, MT, USA,Mechanical Engineering, Montana State University, Bozeman, MT, USA
| | - Christine M. Foreman
- The Center for Biofilm Engineering, Montana State University, Bozeman, MT, USA,Chemical and Biological Engineering, Montana State University, Bozeman, MT, USA
| | - Jiseon Yang
- Biodesign Center for Fundamental and Applied Microbiomics, Arizona State University, Tempe, AZ, USA
| | - Wenyan Li
- Laboratory Support Services and Operations (LASSO), NASA Kennedy Space Center, Cape Canaveral, FL, USA
| | | | - Katelynn Lott
- Department of Biological Sciences, The University of Alabama in Huntsville, Huntsville, AL, USA
| | - Lauren E. HerrNeckar
- ECLSS Development Branch, NASA Marshall Space Flight Center, Huntsville, AL, USA
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6
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Allkja J, Goeres DM, Azevedo AS, Azevedo NF. Interactions of microorganisms within a urinary catheter polymicrobial biofilm model. Biotechnol Bioeng 2023; 120:239-249. [PMID: 36123299 DOI: 10.1002/bit.28241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 09/07/2022] [Accepted: 09/11/2022] [Indexed: 11/11/2022]
Abstract
Biofilms are often polymicrobial in nature, which can impact their behavior and overall structure, often resulting in an increase in biomass and enhanced antimicrobial resistance. Using plate counts and locked nucleic acid/2'-O-methyl-RNA fluorescence in situ hybridization (LNA/2'OMe-FISH), we studied the interactions of four species commonly associated with catheter-associated urinary tract infections (CAUTI): Enterococcus faecalis, Escherichia coli, Candida albicans, and Proteus mirabilis. Eleven combinations of biofilms were grown on silicone coupons placed in 24-well plates for 24 h, 37°C, in artificial urine medium (AUM). Results showed that P. mirabilis was the dominant species and was able to inhibit both E. coli and C. albicans growth. In the absence of P. mirabilis, an antagonistic relationship between E. coli and C. albicans was observed, with the former being dominant. E. faecalis growth was not affected in any combination, showing a more mutualistic relationship with the other species. Imaging results correlated with the plate count data and provided visual verification of species undetected using the viable plate count. Moreover, the three bacterial species showed overall good repeatability SD (Sr ) values (0.1-0.54) in all combinations tested, whereas C. albicans had higher repeatability Sr values (0.36-1.18). The study showed the complexity of early-stage interactions in polymicrobial biofilms. These interactions could serve as a starting point when considering targets for preventing or treating CAUTI biofilms containing these species.
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Affiliation(s)
- Jontana Allkja
- Laboratory for Process Engineering, Environment, Biotechnology and Energy (LEPABE), Faculty of Engineering, University of Porto, Porto, Portugal.,Associate Laboratory in Chemical Engineering (ALiCE), Faculty of Engineering, University of Porto, Porto, Portugal
| | - Darla M Goeres
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana, USA
| | - Andreia S Azevedo
- Laboratory for Process Engineering, Environment, Biotechnology and Energy (LEPABE), Faculty of Engineering, University of Porto, Porto, Portugal.,Associate Laboratory in Chemical Engineering (ALiCE), Faculty of Engineering, University of Porto, Porto, Portugal.,Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal.,Instituto de Patologia e Imunologia Molecular (IPATIMUP), Universidade do Porto, Porto, Portugal
| | - Nuno F Azevedo
- Laboratory for Process Engineering, Environment, Biotechnology and Energy (LEPABE), Faculty of Engineering, University of Porto, Porto, Portugal.,Associate Laboratory in Chemical Engineering (ALiCE), Faculty of Engineering, University of Porto, Porto, Portugal
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7
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Buckingham-Meyer K, Miller LA, Parker AE, Walker DK, Sturman P, Novak I, Goeres DM. Harvesting and Disaggregation: An Overlooked Step in Biofilm Methods Research. J Vis Exp 2022. [DOI: 10.3791/62390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
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8
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Tomasino SF, Pines RM, Goeres DM, Parker AE. Interlaboratory evaluations of a standardized quantitative test method for determining the bactericidal and tuberculocidal efficacy of antimicrobial substances on hard non-porous surfaces. J Microbiol Methods 2022; 196:106460. [DOI: 10.1016/j.mimet.2022.106460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 04/06/2022] [Accepted: 04/06/2022] [Indexed: 12/27/2022]
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9
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Johnson E, Petersen T, Goeres DM. Characterizing the Shearing Stresses within the CDC Biofilm Reactor Using Computational Fluid Dynamics. Microorganisms 2021; 9:microorganisms9081709. [PMID: 34442788 PMCID: PMC8399442 DOI: 10.3390/microorganisms9081709] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 08/04/2021] [Accepted: 08/08/2021] [Indexed: 11/21/2022] Open
Abstract
Shearing stresses are known to be a critical factor impacting the growth and physiology of biofilms, but the underlying fluid dynamics within biofilm reactors are rarely well characterized and not always considered when a researcher decides which biofilm reactor to use. The CDC biofilm reactor is referenced in validated Standard Test Methods and US EPA guidance documents. The driving fluid dynamics within the CDC biofilm reactor were investigated using computational fluid dynamics. An unsteady, three-dimensional model of the CDC reactor was simulated at a rotation rate of 125 RPM. The reactor showed turbulent structures, with shear stresses averaging near 0.365 ± 0.074 Pa across all 24 coupons. The pressure variation on the coupon surfaces was found to be larger, with a continuous 2–3 Pa amplitude, coinciding with the baffle passage. Computational fluid dynamics was shown to be a powerful tool for defining key fluid dynamic parameters at a high fidelity within the CDC biofilm reactor. The consistency of the shear stresses and pressures and the unsteadiness of the flow within the CDC reactor may help explain its reproducibility in laboratory studies. The computational model will enable researchers to make an informed decision whether the fluid dynamics present in the CDC biofilm reactor are appropriate for their research.
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Affiliation(s)
- Erick Johnson
- Department Mechanical Engineering, Montana State University, Bozeman, MT 59717, USA; (E.J.); (T.P.)
- Center for Biofilm Engineering, Montana State University, Bozeman, MT 59717, USA
| | - Theodore Petersen
- Department Mechanical Engineering, Montana State University, Bozeman, MT 59717, USA; (E.J.); (T.P.)
| | - Darla M. Goeres
- Center for Biofilm Engineering, Montana State University, Bozeman, MT 59717, USA
- Correspondence: ; Tel.: +1-406-994-2440
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10
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Azevedo NF, Allkja J, Goeres DM. Biofilms vs. cities and humans vs. aliens - a tale of reproducibility in biofilms. Trends Microbiol 2021; 29:1062-1071. [PMID: 34088548 DOI: 10.1016/j.tim.2021.05.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 05/05/2021] [Accepted: 05/06/2021] [Indexed: 12/14/2022]
Abstract
Biofilms are complex and dynamic structures that include many more components than just viable cells. Therefore, the apparently simple goal of growing reproducible biofilms is often elusive. One of the challenges in defining reproducibility for biofilm research is that different research fields use a spectrum of parameters to define reproducibility for their particular application. For instance, is the researcher interested in achieving a similar population density, height of biofilm structures, or function of the biofilm in a certain ecosystem/industrial context? Within this article we categorize reproducibility into four different levels: level 1, no reproducibility; level 2, standard reproducibility; level 3, potential standard reproducibility; and level 4, total reproducibility. To better understand the need for these different levels of reproducibility, we expand on the 'cities of microbes' analogy for biofilms by imagining that a new civilization has reached the Earth's outskirts and starts studying the Earth's cities. This will provide a better sense of scale and illustrate how small details can impact profoundly on the growth and behavior of a biofilm and our understanding of reproducibility.
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Affiliation(s)
- Nuno F Azevedo
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology, and Energy, Faculty of Engineering, University of Porto, Rua Dr Roberto Frias, 4200-465 Porto, Portugal.
| | - Jontana Allkja
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology, and Energy, Faculty of Engineering, University of Porto, Rua Dr Roberto Frias, 4200-465 Porto, Portugal
| | - Darla M Goeres
- Montana State University, Center for Biofilm Engineering, 366 Barnard Hall, Bozeman, MT 59717, USA
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11
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Walsh DJ, Livinghouse T, Durling GM, Arnold AD, Brasier W, Berry L, Goeres DM, Stewart PS. Novel phenolic antimicrobials enhanced activity of iminodiacetate prodrugs against biofilm and planktonic bacteria. Chem Biol Drug Des 2021; 97:134-147. [PMID: 32844569 PMCID: PMC7821224 DOI: 10.1111/cbdd.13768] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 07/09/2020] [Accepted: 07/19/2020] [Indexed: 12/23/2022]
Abstract
Prodrugs are pharmacologically attenuated derivatives of drugs that undergo bioconversion into the active compound once reaching the targeted site, thereby maximizing their efficiency. This strategy has been implemented in pharmaceuticals to overcome obstacles related to absorption, distribution, and metabolism, as well as with intracellular dyes to ensure concentration within cells. In this study, we provide the first examples of a prodrug strategy that can be applied to simple phenolic antimicrobials to increase their potency against mature biofilms. The addition of (acetoxy)methyl iminodiacetate groups increases the otherwise modest potency of simple phenols. Biofilm-forming bacteria exhibit a heightened tolerance toward antimicrobial agents, thereby accentuating the need for new antibiotics as well as those, which incorporate novel delivery strategies to enhance activity toward biofilms.
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Affiliation(s)
- Danica J. Walsh
- Chemistry and BiochemistryMontana State UniversityBozemanMTUSA
- Center for Biofilm EngineeringMontana State UniversityBozemanMTUSA
| | - Tom Livinghouse
- Chemistry and BiochemistryMontana State UniversityBozemanMTUSA
| | - Greg M. Durling
- Chemistry and BiochemistryMontana State UniversityBozemanMTUSA
| | - Adrienne D. Arnold
- Center for Biofilm EngineeringMontana State UniversityBozemanMTUSA
- Microbiology and ImmunologyMontana State UniversityBozemanMTUSA
| | - Whitney Brasier
- Center for Biofilm EngineeringMontana State UniversityBozemanMTUSA
| | - Luke Berry
- Chemistry and BiochemistryMontana State UniversityBozemanMTUSA
| | - Darla M. Goeres
- Center for Biofilm EngineeringMontana State UniversityBozemanMTUSA
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12
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Goeres DM, Parker AE, Walker DK, Meier K, Lorenz LA, Buckingham-Meyer K. Drip flow reactor method exhibits excellent reproducibility based on a 10-laboratory collaborative study. J Microbiol Methods 2020; 174:105963. [DOI: 10.1016/j.mimet.2020.105963] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/19/2020] [Accepted: 05/19/2020] [Indexed: 11/28/2022]
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13
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Hamilton MA, Buckingham-Meyer K, Goeres DM. Checking the Validity of the Harvesting and Disaggregating Steps in Laboratory Tests of Surface Disinfectants. J AOAC Int 2019. [DOI: 10.1093/jaoac/92.6.1755] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
A chemical disinfectant against surface-associated bacteria typically uses carriers (e.g., glass disks) that are purposely contaminated with bacteria prior to disinfection. After disinfection, the bacteria are harvested by mechanically separating them from the carrier surface to form a suspension of cells in a dilution tube. Bacterial clumps in the tube are disaggregated using mechanical or chemical techniques, thereby creating a well-mixed suspension of single cells suitable for enumeration. Efficacy is quantified by comparing the viable cell count for a disinfected carrier to the viable cell count for sham-disinfected (control) carrier. A test is said to be biased (invalid) if the observed efficacy measure is systematically higher or lower than the true efficacy. It is shown here for the first time that the bias attributable to the harvesting and disaggregating steps of a disinfectant test can be measured. For some conventional biofilm harvesting and disaggregating techniques, laboratory checks showed either negligible bias or important bias, depending on the disinfectant. Quantitative bias checks on the harvesting and disaggregating steps are prudent for each combination of carrier material, microorganism, and disinfectant. The quantitative results should be augmented by microscopic examination of harvested disinfected and control carriers and of the disaggregated suspensions.
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Affiliation(s)
- Martin A Hamilton
- Montana State University, Center for Biofilm Engineering, Bozeman, MT 59717-3980 and Big Sky Statistical Analysts LLC, 309 South Sixth Ave, Bozeman, MT 59715
| | | | - Darla M Goeres
- Montana State University, Center for Biofilm Engineering, Bozeman, MT 59717-3980
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14
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Allkja J, Bjarnsholt T, Coenye T, Cos P, Fallarero A, Harrison JJ, Lopes SP, Oliver A, Pereira MO, Ramage G, Shirtliff ME, Stoodley P, Webb JS, Zaat SAJ, Goeres DM, Azevedo NF. Minimum information guideline for spectrophotometric and fluorometric methods to assess biofilm formation in microplates. Biofilm 2019; 2:100010. [PMID: 33447797 PMCID: PMC7798448 DOI: 10.1016/j.bioflm.2019.100010] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 11/08/2019] [Accepted: 11/10/2019] [Indexed: 12/11/2022] Open
Abstract
The lack of reproducibility of published studies is one of the major issues facing the scientific community, and the field of biofilm microbiology has been no exception. One effective strategy against this multifaceted problem is the use of minimum information guidelines. This strategy provides a guide for authors and reviewers on the necessary information that a manuscript should include for the experiments in a study to be clearly interpreted and independently reproduced. As a result of several discussions between international groups working in the area of biofilms, we present a guideline for the spectrophotometric and fluorometric assessment of biofilm formation in microplates. This guideline has been divided into 5 main sections, each presenting a comprehensive set of recommendations. The intention of the minimum information guideline is to improve the quality of scientific communication that will augment interlaboratory reproducibility in biofilm microplate assays.
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Affiliation(s)
- Jontana Allkja
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal.,Montana State University, Center for Biofilm Engineering, 366 Barnard Hall, Bozeman, MT, 59717, USA
| | - Thomas Bjarnsholt
- Department of Clinical Microbiology, Rigshospitalet, 2100, Copenhagen, Denmark.,Department of Immunology and Microbiology, Costerton Biofilm Center, Faculty of Health Sciences University of Copenhagen, 2200, Copenhagen, Denmark.,ESCMID Study Group for Biofilms, Basel, Switzerland
| | - Tom Coenye
- ESCMID Study Group for Biofilms, Basel, Switzerland.,Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Paul Cos
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Antwerp, Belgium
| | - Adyary Fallarero
- Pharmaceutical Design and Discovery (PharmDD), Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Viikinkaari 5E, P.O. Box 56, FI-00014, Helsinki, Finland
| | - Joe J Harrison
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada
| | - Susana P Lopes
- Centre of Biological Engineering (CEB), Laboratório de Investigação Em Biofilmes Rosário Oliveira (LIBRO), University of Minho, Braga, Portugal
| | - Antonio Oliver
- Servicio de Microbiología, Hospital Universitario Son Espases, Instituto de Investigación Sanitaria Illes Balears (IdISBa), Palma de Mallorca, Spain
| | - Maria Olivia Pereira
- Centre of Biological Engineering (CEB), Laboratório de Investigação Em Biofilmes Rosário Oliveira (LIBRO), University of Minho, Braga, Portugal
| | - Gordon Ramage
- Oral Sciences Research Group, University of Glasgow Dental School, School of Medicine, Dentistry and Nursing, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom.,ESCMID Study Group for Biofilms, Basel, Switzerland
| | - Mark E Shirtliff
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD, 21201, USA
| | - Paul Stoodley
- Department of Microbial Infection and Immunity and Orthopedics, The Ohio State University, Columbus, OH, 43210, USA.,National Centre for Advanced Tribiology at Southampton (nCATS), Department of Mechanical Engineering, University of Southampton, Southampton, SO17 1BJ, UK.,National Biofilms Innovation Centre, School of Biological Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Jeremy S Webb
- National Biofilms Innovation Centre, School of Biological Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Sebastian A J Zaat
- Amsterdam UMC, University of Amsterdam, Department of Medical Microbiology, Amsterdam Infection and Immunity Institute, Meibergdreef 9, 1105AZ, Amsterdam, the Netherlands
| | - Darla M Goeres
- Montana State University, Center for Biofilm Engineering, 366 Barnard Hall, Bozeman, MT, 59717, USA
| | - Nuno Filipe Azevedo
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
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15
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Goeres DM, Walker DK, Buckingham-Meyer K, Lorenz L, Summers J, Fritz B, Goveia D, Dickerman G, Schultz J, Parker AE. Development, standardization, and validation of a biofilm efficacy test: The single tube method. J Microbiol Methods 2019; 165:105694. [DOI: 10.1016/j.mimet.2019.105694] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 08/17/2019] [Accepted: 08/17/2019] [Indexed: 01/20/2023]
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16
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Walsh DJ, Livinghouse T, Goeres DM, Mettler M, Stewart PS. Antimicrobial Activity of Naturally Occurring Phenols and Derivatives Against Biofilm and Planktonic Bacteria. Front Chem 2019; 7:653. [PMID: 31632948 PMCID: PMC6779693 DOI: 10.3389/fchem.2019.00653] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 09/11/2019] [Indexed: 12/28/2022] Open
Abstract
Biofilm-forming bacteria present formidable challenges across diverse settings, and there is a need for new antimicrobial agents that are both environmentally acceptable and relatively potent against microorganisms in the biofilm state. The antimicrobial activity of three naturally occurring, low molecular weight, phenols, and their derivatives were evaluated against planktonic and biofilm Staphylococcus epidermidis and Pseudomonas aeruginosa. The structure activity relationships of eugenol, thymol, carvacrol, and their corresponding 2- and 4-allyl, 2-methallyl, and 2- and 4-n-propyl derivatives were evaluated. Allyl derivatives showed a consistent increased potency with both killing and inhibiting planktonic cells but they exhibited a decrease in potency against biofilms. This result underscores the importance of using biofilm assays to develop structure-activity relationships when the end target is biofilm.
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Affiliation(s)
- Danica J. Walsh
- Chemistry and Biochemistry, Montana State University, Bozeman, MT, United States
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, United States
| | - Tom Livinghouse
- Chemistry and Biochemistry, Montana State University, Bozeman, MT, United States
| | - Darla M. Goeres
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, United States
| | - Madelyn Mettler
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, United States
| | - Philip S. Stewart
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, United States
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17
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Abstract
We review reproducibility results for methods that test antimicrobial efficacy against biofilms, spores and bacteria dried onto a surface. Our review, that included test results for Pseudomonas aeruginosa, Salmonella choleraesuis and Bacillus subtilis, suggests that the level of reproducibility depends on the efficacy of the antimicrobial agent being tested for each microbe and microbial environment. To determine the reproducibility of a method, several laboratories must independently test the same antimicrobial agent using the method. Little variability among the efficacy results suggests good reproducibility. Such reproducibility assessments currently are hampered by the absence of an objective process for deciding whether the variability is sufficiently small. We present a quantitative decision process that objectively determines whether any method that assesses antimicrobial efficacy is reproducible. Because the perception of acceptable reproducibility may differ among stakeholders, the decision process is governed by a stakeholder's specifications that necessarily includes the efficacy of the agents to be tested.
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Affiliation(s)
- Albert E Parker
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana, USA.
- Department of Mathematical Sciences, Montana State University, Bozeman, Montana, USA.
| | - Martin A Hamilton
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana, USA
- Department of Mathematical Sciences, Montana State University, Bozeman, Montana, USA
| | - Darla M Goeres
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana, USA
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18
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Ausbacher D, Lorenz L, Pitts B, Stewart PS, Goeres DM. Paired methods to measure biofilm killing and removal: a case study with Penicillin G treatment of Staphylococcus aureus biofilm. Lett Appl Microbiol 2017; 66:231-237. [PMID: 29288553 DOI: 10.1111/lam.12843] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 12/22/2017] [Accepted: 12/22/2017] [Indexed: 11/28/2022]
Abstract
Biofilms are microbial aggregates that show high tolerance to antibiotic treatments in vitro and in vivo. Killing and removal are both important in biofilm control, therefore methods that measure these two mechanisms were evaluated in a parallel experimental design. Kill was measured using the single tube method (ASTM method E2871) and removal was determined by video microscopy and image analysis using a new treatment flow cell. The advantage of the parallel test design is that both methods used biofilm covered coupons harvested from a CDC biofilm reactor, a well-established and standardized biofilm growth method. The control Staphylococcus aureus biofilms treated with growth medium increased by 0·6 logs during a 3-h contact time. Efficacy testing showed biofilms exposed to 400 μmol l-1 penicillin G decreased by only 0·3 logs. Interestingly, time-lapse confocal scanning laser microscopy revealed that penicillin G treatment dispersed the biofilm despite being an ineffective killing agent. In addition, no biofilm removal was detected when assays were performed in 96-well plates. These results illustrate that biofilm behaviour and impact of treatments can vary substantially when assayed by different methods. Measuring both killing and removal with well-characterized methods will be crucial for the discovery of new anti-biofilm strategies. SIGNIFICANCE AND IMPACT OF THE STUDY Biofilms are tolerant to antimicrobial treatments and can lead to persistent infections. Finding new anti-biofilm strategies and understanding their mode-of-action is therefore of high importance. Historically, antimicrobial testing has focused on measuring the decrease in viability. While kill data are undeniably important, measuring biofilm disruption provides equally useful information. Starting with biofilm grown in the same reactor, we paired assessment of biofilm removal using a new treatment-flow-cell and real-time microscopy with kill data collected using the single tube method (ASTM E2871). Pairing these two methods revealed efficient biofilm removal properties of Penicillin G which were not detected during efficacy testing.
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Affiliation(s)
- D Ausbacher
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, USA
| | - L Lorenz
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, USA
| | - B Pitts
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, USA
| | - P S Stewart
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, USA
| | - D M Goeres
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, USA
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19
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Gomes IB, Meireles A, Gonçalves AL, Goeres DM, Sjollema J, Simões LC, Simões M. Standardized reactors for the study of medical biofilms: a review of the principles and latest modifications. Crit Rev Biotechnol 2017; 38:657-670. [DOI: 10.1080/07388551.2017.1380601] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Inês B. Gomes
- LEPABE – Laboratório de Engenharia de Processos, Ambiente, Biotecnologia e Energia, Faculdade de Engenharia da Universidade do Porto, Porto, Portugal
| | - Ana Meireles
- LEPABE – Laboratório de Engenharia de Processos, Ambiente, Biotecnologia e Energia, Faculdade de Engenharia da Universidade do Porto, Porto, Portugal
| | - Ana L. Gonçalves
- LEPABE – Laboratório de Engenharia de Processos, Ambiente, Biotecnologia e Energia, Faculdade de Engenharia da Universidade do Porto, Porto, Portugal
| | - Darla M. Goeres
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, USA
| | - Jelmer Sjollema
- University of Groningen, University Medical Center Groningen, Department of Biomedical Engineering, Groningen, The Netherlands
| | - Lúcia C. Simões
- LEPABE – Laboratório de Engenharia de Processos, Ambiente, Biotecnologia e Energia, Faculdade de Engenharia da Universidade do Porto, Porto, Portugal
| | - Manuel Simões
- LEPABE – Laboratório de Engenharia de Processos, Ambiente, Biotecnologia e Energia, Faculdade de Engenharia da Universidade do Porto, Porto, Portugal
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20
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Manner S, Goeres DM, Skogman M, Vuorela P, Fallarero A. Prevention of Staphylococcus aureus biofilm formation by antibiotics in 96-Microtiter Well Plates and Drip Flow Reactors: critical factors influencing outcomes. Sci Rep 2017; 7:43854. [PMID: 28252025 PMCID: PMC5333151 DOI: 10.1038/srep43854] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 01/31/2017] [Indexed: 12/27/2022] Open
Abstract
Biofilm formation leads to the failure of antimicrobial therapy. Thus, biofilm prevention is a desirable goal of antimicrobial research. In this study, the efficacy of antibiotics (doxycycline, oxacillin and rifampicin) in preventing Staphylococcus aureus biofilms was investigated using Microtiter Well Plates (MWP) and Drip Flow Reactors (DFR), two models characterized by the absence and the presence of a continuous flow of nutrients, respectively. Planktonic culture of S. aureus was exposed to antibiotics for one hour followed by 24 hours incubation with fresh nutrients in MWP or continuous flow of nutrients in DFR. The DFR grown biofilms were significantly more tolerant to the antibiotics than those grown in MWP without the continuous flow. The differences in log reductions (LR) between the two models could not be attributed to differences in the cell density, the planktonic inoculum concentration or the surface-area-to-volume ratios. However, eliminating the flow in the DFR significantly restored the antibiotic susceptibility. These findings demonstrate the importance of considering differences between experimental conditions in different model systems, particularly the flow of nutrients, when performing anti-biofilm efficacy evaluations. Biofilm antibiotic efficacy studies should be assessed using various models and more importantly, in a model mimicking conditions of its clinical application.
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Affiliation(s)
- Suvi Manner
- Pharmaceutical Sciences Laboratory, Faculty of Science and Engineering, Abo Akademi University, BioCity, Artillerigatan 6A, FI-20520, Turku, Finland
| | - Darla M Goeres
- Center for Biofilm Engineering, Montana State University, Bozeman, MT 59717, USA
| | - Malena Skogman
- Pharmaceutical Design and Discovery (PharmDD), Pharmaceutical Biology, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Viikinkaari 5E, P.O. Box 56, FI-00014 University of Helsinki, Finland
| | - Pia Vuorela
- Pharmaceutical Design and Discovery (PharmDD), Pharmaceutical Biology, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Viikinkaari 5E, P.O. Box 56, FI-00014 University of Helsinki, Finland
| | - Adyary Fallarero
- Pharmaceutical Design and Discovery (PharmDD), Pharmaceutical Biology, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Viikinkaari 5E, P.O. Box 56, FI-00014 University of Helsinki, Finland
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21
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Malone M, Goeres DM, Gosbell I, Vickery K, Jensen S, Stoodley P. Approaches to biofilm-associated infections: the need for standardized and relevant biofilm methods for clinical applications. Expert Rev Anti Infect Ther 2017. [PMID: 27858472 DOI: 10.1080/14787210.2017.1262257)] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The concept of biofilms in human health and disease is now widely accepted as cause of chronic infection. Typically, biofilms show remarkable tolerance to many forms of treatments and the host immune response. This has led to vast increase in research to identify new (and sometimes old) anti-biofilm strategies that demonstrate effectiveness against these tolerant phenotypes. Areas covered: Unfortunately, a standardized methodological approach of biofilm models has not been adopted leading to a large disparity between testing conditions. This has made it almost impossible to compare data across multiple laboratories, leaving large gaps in the evidence. Furthermore, many biofilm models testing anti-biofilm strategies aimed at the medical arena have not considered the matter of relevance to an intended application. This may explain why some in vitro models based on methodological designs that do not consider relevance to an intended application fail when applied in vivo at the clinical level. Expert commentary: This review will explore the issues that need to be considered in developing performance standards for anti-biofilm therapeutics and provide a rationale for the need to standardize models/methods that are clinically relevant. We also provide some rational as to why no standards currently exist.
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Affiliation(s)
- Matthew Malone
- a Molecular Microbiology Research Group, Faculty of Medicine , Western Sydney University , Sydney , Australia
- b Liverpool Diabetes Collaborative Research Group , Ingham Institute of Applied Medical Research , Liverpool , Australia
| | - Darla M Goeres
- c Center for Biofilm Engineering , Montana State University , Bozeman , MT , USA
| | - Iain Gosbell
- a Molecular Microbiology Research Group, Faculty of Medicine , Western Sydney University , Sydney , Australia
| | - Karen Vickery
- d Surgical Infection Research Group, Faculty of Medicine and Health Sciences , Macquarie University , Sydney , Australia
| | - Slade Jensen
- a Molecular Microbiology Research Group, Faculty of Medicine , Western Sydney University , Sydney , Australia
| | - Paul Stoodley
- e Departments of Microbial Infection and Immunity, Orthopedics, Center for Microbial Interface Biology , The Ohio State University , Columbus , OH , USA
- f National Centre for Advanced Tribology (nCATS), Engineering Sciences , University of Southampton , Southampton , UK
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22
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Malone M, Goeres DM, Gosbell I, Vickery K, Jensen S, Stoodley P. Approaches to biofilm-associated infections: the need for standardized and relevant biofilm methods for clinical applications. Expert Rev Anti Infect Ther 2016; 15:147-156. [PMID: 27858472 DOI: 10.1080/14787210.2017.1262257] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
INTRODUCTION The concept of biofilms in human health and disease is now widely accepted as cause of chronic infection. Typically, biofilms show remarkable tolerance to many forms of treatments and the host immune response. This has led to vast increase in research to identify new (and sometimes old) anti-biofilm strategies that demonstrate effectiveness against these tolerant phenotypes. Areas covered: Unfortunately, a standardized methodological approach of biofilm models has not been adopted leading to a large disparity between testing conditions. This has made it almost impossible to compare data across multiple laboratories, leaving large gaps in the evidence. Furthermore, many biofilm models testing anti-biofilm strategies aimed at the medical arena have not considered the matter of relevance to an intended application. This may explain why some in vitro models based on methodological designs that do not consider relevance to an intended application fail when applied in vivo at the clinical level. Expert commentary: This review will explore the issues that need to be considered in developing performance standards for anti-biofilm therapeutics and provide a rationale for the need to standardize models/methods that are clinically relevant. We also provide some rational as to why no standards currently exist.
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Affiliation(s)
- Matthew Malone
- a Molecular Microbiology Research Group, Faculty of Medicine , Western Sydney University , Sydney , Australia.,b Liverpool Diabetes Collaborative Research Group , Ingham Institute of Applied Medical Research , Liverpool , Australia
| | - Darla M Goeres
- c Center for Biofilm Engineering , Montana State University , Bozeman , MT , USA
| | - Iain Gosbell
- a Molecular Microbiology Research Group, Faculty of Medicine , Western Sydney University , Sydney , Australia
| | - Karen Vickery
- d Surgical Infection Research Group, Faculty of Medicine and Health Sciences , Macquarie University , Sydney , Australia
| | - Slade Jensen
- a Molecular Microbiology Research Group, Faculty of Medicine , Western Sydney University , Sydney , Australia
| | - Paul Stoodley
- e Departments of Microbial Infection and Immunity, Orthopedics, Center for Microbial Interface Biology , The Ohio State University , Columbus , OH , USA.,f National Centre for Advanced Tribology (nCATS), Engineering Sciences , University of Southampton , Southampton , UK
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23
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Parker AE, Walker DK, Goeres DM, Allan N, Olson ME, Omar A. Ruggedness and reproducibility of the MBEC biofilm disinfectant efficacy test. J Microbiol Methods 2014; 102:55-64. [PMID: 24815513 DOI: 10.1016/j.mimet.2014.04.013] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 04/29/2014] [Accepted: 04/29/2014] [Indexed: 10/25/2022]
Abstract
The MBEC™ Physiology & Genetics Assay recently became the first approved ASTM standardized biofilm disinfectant efficacy test method. This report summarizes the results of the standardization process using Pseudomonas aeruginosa biofilms. Initial ruggedness testing of the MBEC method suggests that the assay is rugged (i.e., insensitive) to small changes to the protocol with respect to 4 factors: incubation time of the bacteria (when varied from 16 to 18h), treatment temperature (20-24°C), sonication duration (25-35min), and sonication power (130-480W). In order to assess the repeatability of MBEC results across multiple tests in the same laboratory and the reproducibility across multiple labs, an 8-lab study was conducted in which 8 concentrations of each of 3 disinfectants (a non-chlorine oxidizer, a phenolic, and a quaternary ammonium compound) were applied to biofilms using the MBEC method. The repeatability and reproducibility of the untreated control biofilms were acceptable, as indicated by small repeatability and reproducibility standard deviations (SD) (0.33 and 0.67 log10(CFU/mm(2)), respectively). The repeatability SDs of the biofilm log reductions after application of the 24 concentration and disinfectant combinations ranged from 0.22 to 1.61, and the reproducibility SDs ranged from 0.27 to 1.70. In addition, for each of the 3 disinfectant types considered, the assay was statistically significantly responsive to the increasing treatment concentrations.
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Affiliation(s)
- A E Parker
- Center for Biofilm Engineering, Montana State University, Bozeman, MT 59715, USA; Department of Mathematical Sciences, Montana State University, Bozeman, MT 59715, USA.
| | - D K Walker
- Center for Biofilm Engineering, Montana State University, Bozeman, MT 59715, USA
| | - D M Goeres
- Center for Biofilm Engineering, Montana State University, Bozeman, MT 59715, USA
| | - N Allan
- Innovotech Inc., Edmonton AB T6N 1H1, Canada
| | - M E Olson
- Innovotech Inc., Edmonton AB T6N 1H1, Canada
| | - A Omar
- Innovotech Inc., Edmonton AB T6N 1H1, Canada
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24
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Lourenço A, Coenye T, Goeres DM, Donelli G, Azevedo AS, Ceri H, Coelho FL, Flemming HC, Juhna T, Lopes SP, Oliveira R, Oliver A, Shirtliff ME, Sousa AM, Stoodley P, Pereira MO, Azevedo NF. Minimum information about a biofilm experiment (MIABiE): standards for reporting experiments and data on sessile microbial communities living at interfaces. Pathog Dis 2014; 70:250-6. [PMID: 24478124 DOI: 10.1111/2049-632x.12146] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 01/15/2014] [Accepted: 01/15/2014] [Indexed: 02/04/2023] Open
Abstract
The minimum information about a biofilm experiment (MIABiE) initiative has arisen from the need to find an adequate and scientifically sound way to control the quality of the documentation accompanying the public deposition of biofilm-related data, particularly those obtained using high-throughput devices and techniques. Thereby, the MIABiE consortium has initiated the identification and organization of a set of modules containing the minimum information that needs to be reported to guarantee the interpretability and independent verification of experimental results and their integration with knowledge coming from other fields. MIABiE does not intend to propose specific standards on how biofilms experiments should be performed, because it is acknowledged that specific research questions require specific conditions which may deviate from any standardization. Instead, MIABiE presents guidelines about the data to be recorded and published in order for the procedure and results to be easily and unequivocally interpreted and reproduced. Overall, MIABiE opens up the discussion about a number of particular areas of interest and attempts to achieve a broad consensus about which biofilm data and metadata should be reported in scientific journals in a systematic, rigorous and understandable manner.
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Affiliation(s)
- Anália Lourenço
- Departamento de Informática, Universidade de Vigo, ESEI - Escuela Superior de Ingeniería Informática, Ourense, Spain; IBB - Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho, Braga, Portugal
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25
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Hamilton MA, Hamilton GC, Goeres DM, Parker AE. Guidelines for the statistical analysis of a collaborative study of a laboratory method for testing disinfectant product performance. J AOAC Int 2014; 96:1138-51. [PMID: 24282959 DOI: 10.5740/jaoacint.12-217] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This paper presents statistical techniques suitable for analyzing a collaborative study (multilaboratory study or ring trial) of a laboratory disinfectant product performance test (DPPT) method. Emphasis is on the assessment of the repeatability, reproducibility, resemblance, and responsiveness of the DPPT method. The suggested statistical techniques are easily modified for application to a single laboratory study. The presentation includes descriptions of the plots and tables that should be constructed during initial examination of the data, including a discussion of outliers and QA checks. The statistical recommendations deal with evaluations of prevailing types of DPPTs, including both quantitative and semiquantitative tests. The presentation emphasizes tests in which the disinfectant treatment is applied to surface-associated microbes and the outcome is a viable cell count; however, the statistical guidelines are appropriate for suspension tests and other test systems. The recommendations also are suitable for disinfectant tests using any microbe (vegetative bacteria, virus, spores, etc.) or any disinfectant treatment. The descriptions of the statistical techniques include either examples of calculations based on published data or citations to published calculations. Computer code is provided in an appendix.
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Affiliation(s)
- Martin A Hamilton
- Big Sky Statistical Analysts LLC, 309 South Sixth Ave, Bozeman, MT 59715, USA
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26
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Abstract
Recent studies evaluating bulk soap in public restroom soap dispensers have demonstrated up to 25% of open refillable bulk-soap dispensers were contaminated with ~ 6 log(10)(CFU ml(-1)) heterotrophic bacteria. In this study, plastic counter-mounted, plastic wall-mounted and stainless steel wall-mounted dispensers were analyzed for suspended and biofilm bacteria using total cell and viable plate counts. Independent of dispenser type or construction material, the bulk soap was contaminated with 4-7 log(10)(CFU ml(-1)) bacteria, while 4-6 log(10)(CFU cm(-2)) biofilm bacteria were isolated from the inside surfaces of the dispensers (n = 6). Dispenser remediation studies, including a 10 min soak with 5000 mg l(-1) sodium hypochlorite, were then conducted to determine the efficacy of cleaning and disinfectant procedures against established biofilms. The testing showed that contamination of the bulk soap returned to pre-test levels within 7-14 days. These results demonstrate biofilm is present in contaminated bulk-soap dispensers and remediation studies to clean and sanitize the dispensers are temporary.
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Affiliation(s)
- Lindsey A Lorenz
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana 59717, USA
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27
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Saha R, Donofrio RS, Goeres DM, Bagley ST. Rapid detection of rRNA group I pseudomonads in contaminated metalworking fluids and biofilm formation by fluorescent in situ hybridization. Appl Microbiol Biotechnol 2011; 94:799-808. [DOI: 10.1007/s00253-011-3647-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 09/28/2011] [Accepted: 10/16/2011] [Indexed: 11/29/2022]
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Hamilton MA, Buckingham-Meyer K, Goeres DM. Checking the validity of the harvesting and disaggregating steps in laboratory tests of surface disinfectants. J AOAC Int 2009; 92:1755-1762. [PMID: 20166594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A chemical disinfectant against surface-associated bacteria typically uses carriers (e.g., glass disks) that are purposely contaminated with bacteria prior to disinfection. After disinfection, the bacteria are harvested by mechanically separating them from the carrier surface to form a suspension of cells in a dilution tube. Bacterial clumps in the tube are disaggregated using mechanical or chemical techniques, thereby creating a well-mixed suspension of single cells suitable for enumeration. Efficacy is quantified by comparing the viable cell count for a disinfected carrier to the viable cell count for sham-disinfected (control) carrier. A test is said to be biased (invalid) if the observed efficacy measure is systematically higher or lower than the true efficacy. It is shown here for the first time that the bias attributable to the harvesting and disaggregating steps of a disinfectant test can be measured. For some conventional biofilm harvesting and disaggregating techniques, laboratory checks showed either negligible bias or important bias, depending on the disinfectant. Quantitative bias checks on the harvesting and disaggregating steps are prudent for each combination of carrier material, microorganism, and disinfectant. The quantitative results should be augmented by microscopic examination of harvested disinfected and control carriers and of the disaggregated suspensions.
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Affiliation(s)
- Martin A Hamilton
- Montana State University, Center for Biofilm Engineering, Bozeman, MT 59717-3980, USA.
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29
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Buckingham-Meyer K, Goeres DM, Hamilton MA. Comparative evaluation of biofilm disinfectant efficacy tests. J Microbiol Methods 2007; 70:236-44. [PMID: 17524505 DOI: 10.1016/j.mimet.2007.04.010] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2007] [Revised: 04/18/2007] [Accepted: 04/18/2007] [Indexed: 10/23/2022]
Abstract
Regulatory agencies are receiving registration applications for unprecedented, antibiofilm label claims for disinfectants. Reliable, practical, and relevant laboratory biofilm test methods are required to support such claims. This investigation describes the influence of fluid dynamics on the relevancy of a laboratory test. Several disinfectant formulations were tested using three different biofilm testing systems run side-by-side: the CDC biofilm reactor system that created turbulent flow (Reynolds number between 800 and 1850), the drip flow biofilm reactor system that created slow laminar flow (Reynolds number between 12 and 20), and the static biofilm system that involved no fluid flow. Each comparative experiment also included a dried surface carrier test and a dried biofilm test. All five disinfectant tests used glass coupons and followed the same steps for treatment, neutralization, viable cell counting, and calculating the log reduction (LR). Three different disinfectants, chlorine, a quaternary ammonium compound, and a phenolic, were each applied at two concentrations. Experiments were conducted separately with Pseudomonas aeruginosa and Staphylococcus aureus and every experiment was independently repeated. The results showed that biofilm grown in the CDC reactor produced the smallest LR, the static biofilm produced the largest LR, and biofilm grown in the drip flow reactor produced an intermediate LR. The differences were large enough to be of practical importance. The dried surface test often produced a significantly higher LR than the tests against hydrated or dried biofilm. The dried biofilm test produced LR values similar to those for the corresponding hydrated biofilm test. These results show that the efficacy of a disinfectant must be measured by using a laboratory method where biofilm is grown under fluid flow conditions similar to the environment where the disinfectant will be applied.
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Goeres DM, Loetterle LR, Hamilton MA. A laboratory hot tub model for disinfectant efficacy evaluation. J Microbiol Methods 2007; 68:184-92. [PMID: 16949693 DOI: 10.1016/j.mimet.2006.07.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2006] [Revised: 07/13/2006] [Accepted: 07/14/2006] [Indexed: 11/29/2022]
Abstract
This paper describes a novel laboratory hot tub (LHT) apparatus and associated standard operating procedure (SOP) designed to reproduce the key biological, chemical, and engineering parameters associated with recreational and therapeutic hot tubs. Efficacy, as measured quantitatively by log reduction values, was determined against both biofilm and planktonic bacteria. When the LHT was run according to the SOP, with no antimicrobial treatment, a consistent level of bacterial contamination occurred. The means of log10 viable cell densities (+/- the repeatability standard deviation of log densities) were 7.2 (+/-0.31) for the bulk water (density in units of cfu ml-1), 5.3 (+/-0.56) for the coupons (density in units of cfu cm-2), and 6.6 (+/-0.50) for the filters (density in units of cfu cm-2). When control and chlorine treated LHTs were run in parallel, the log reduction increased significantly with chlorine concentration for samples of planktonic bacteria in the bulk water (p=0.016), biofilm bacteria on the coupons (p=0.09) and biofilm bacteria on the filter (p=0.005), indicating that the method was sensitive to chlorine concentration. The method also displayed sensitivity by differentiating between chlorine and bromine treatments; in every case, chlorine produced a greater log reduction than did the same concentration of bromine. The model and SOP were shown to be rugged with respect to slight changes in fluid mixing intensity, water chemistry (saturation index), inoculum size, and organic loading. The LHT and associated SOP provide a reliable second tier in a three-tiered testing process, in which the first tier is a suspension test and the final tier is a field test.
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Affiliation(s)
- Darla M Goeres
- Center for Biofilm Engineering, 366 EPS Building, Montana State University, Bozeman, MT 59717-3980, USA.
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Goeres DM, Loetterle LR, Hamilton MA, Murga R, Kirby DW, Donlan RM. Statistical assessment of a laboratory method for growing biofilms. Microbiology (Reading) 2005; 151:757-762. [PMID: 15758222 DOI: 10.1099/mic.0.27709-0] [Citation(s) in RCA: 188] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Microbial biofilms have been grown in laboratories using a variety of different approaches. A laboratory biofilm reactor system, called the CDC biofilm reactor (CBR) system, has been devised for growing biofilms under moderate to high fluid shear stress. The reactor incorporates 24 removable biofilm growth surfaces (coupons) for sampling and analysing the biofilm. Following preliminary experiments to verify the utility of the CBR system for growing biofilms of several clinically relevant organisms, a standard operating procedure for growing a Pseudomonas aeruginosa biofilm was created. This paper presents the results of a rigorous, intra-laboratory, statistical evaluation of the repeatability and ruggedness of that procedure as well as the results of the experiments with clinically relevant organisms. For the statistical evaluations, the outcome of interest was the density (c.f.u. cm(-2)) of viable P. aeruginosa. Replicate experiments were conducted to assess the repeatability of the log density outcome. The mean P. aeruginosa log10 density was 7.1, independent of the coupon position within the reactor. The repeatability standard deviation of the log density based on one coupon per experiment was 0.59. Analysis of variance showed that the variability of the log density was 53 % attributable to within-experiment sources and 47 % attributable to between-experiments sources. The ruggedness evaluation applied response-surface design and regression analysis techniques, similar to those often used for sensitivity analyses in other fields of science and engineering. This approach provided a quantitative description of ruggedness; specifically, the amount the log density was altered by small adjustments to four key operational factors--time allowed for initial surface colonization, temperature, nutrient concentration, and fluid shear stress on the biofilm. The small size of the regression coefficient associated with each operational factor showed that the method was rugged; that is, relatively insensitive to minor perturbations of the four factors. These results demonstrate that the CBR system is a reliable experimental tool for growing a standard biofilm in the laboratory and that it can be adapted to study several different micro-organisms.
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Affiliation(s)
- Darla M Goeres
- Center for Biofilm Engineering, Montana State University, Bozeman, MT 59717-3980, USA
| | - Linda R Loetterle
- Center for Biofilm Engineering, Montana State University, Bozeman, MT 59717-3980, USA
| | - Martin A Hamilton
- Center for Biofilm Engineering, Montana State University, Bozeman, MT 59717-3980, USA
| | - Ricardo Murga
- Biofilm Laboratory, Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
| | - Douglas W Kirby
- Scientific Resources Program, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
| | - Rodney M Donlan
- Biofilm Laboratory, Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
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Goeres DM, Palys T, Sandel BB, Geiger J. Evaluation of disinfectant efficacy against biofilm and suspended bacteria in a laboratory swimming pool model. Water Res 2004; 38:3103-3109. [PMID: 15261549 DOI: 10.1016/j.watres.2004.04.041] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2003] [Revised: 02/27/2004] [Accepted: 04/15/2004] [Indexed: 05/24/2023]
Abstract
Laboratory reactor systems designed to model specific environments enable researchers to explore environmental dynamics in a more controlled manner. This paper describes the design and operation of a reactor system built to model a swimming pool in the laboratory. The model included relevant engineering parameters such as filter loading and turn-overs per day. The water chemistry in the system's bulk water was balanced according to standard recommendations and the system was challenged with a bacterial load and synthetic bather insult, formulated to represent urine and perspiration. The laboratory model was then used to evaluate the efficacy of six chemical treatments against biofilm and planktonic bacteria. Results showed that the biofilm was able to accumulate on coupons and in the filter systems of reactors treated with either 1-3 mg/L free chlorine or 10 mg/L polyhexamethylene biguanide (PHMB). All the treatments tested resulted in at least a 4 log reduction in biofilm density when compared to the control, but shock treatments were the most effective at controlling biofilm accumulation. A once weekly shock dose of 10 mg/L free chlorine resulted in the greatest log reduction in biofilm density. The research demonstrated the importance of studying a biofilm in addition to the planktonic bacteria to assess the microbial dynamics that exist in a swimming pool model.
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Affiliation(s)
- D M Goeres
- Center for Biofilm Engineering, 366 EPS Building, Montana State University-Bozeman, Bozeman, MT 59717 3980, USA.
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