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Ray S, Löffler S, Richter‐Dahlfors A. High-Resolution Large-Area Image Analysis Deciphers the Distribution of Salmonella Cells and ECM Components in Biofilms Formed on Charged PEDOT:PSS Surfaces. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2307322. [PMID: 38225703 PMCID: PMC11251553 DOI: 10.1002/advs.202307322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 12/12/2023] [Indexed: 01/17/2024]
Abstract
Biofilms, comprised of cells embedded in extracellular matrix (ECM), enable bacterial surface colonization and contribute to pathogenesis and biofouling. Yet, antibacterial surfaces are mainly evaluated for their effect on bacterial cells rather than the ECM. Here, a method is presented to separately quantify amounts and distribution of cells and ECM in Salmonella biofilms grown on electroactive poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS). Within a custom-designed biofilm reactor, biofilm forms on PEDOT:PSS surfaces electrically addressed with a bias potential and simultaneous recording of the resulting current. The amount and distribution of cells and ECM in biofilms are analyzed using a fluorescence-based spectroscopic mapping technique and fluorescence confocal microscopy combined with advanced image processing. The study shows that surface charge leads to upregulated ECM production, leaving the cell counts largely unaffected. An altered texture is also observed, with biofilms forming small foci or more continuous structures. Supported by mutants lacking ECM production, ECM is identified as an important target when developing antibacterial strategies. Also, a central role for biofilm distribution is highlighted that likely influences antimicrobial susceptibility in biofilms. This work provides yet a link between conductive polymer materials and bacterial metabolism and reveals for the first time a specific effect of electrochemical addressing on bacterial ECM formation.
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Affiliation(s)
- Sanhita Ray
- AIMES – Center for the Advancement of Integrated Medical and Engineering Sciences at Karolinska Institutet and KTH Royal Institute of TechnologyStockholmSE‐171 77Sweden
- Department of NeuroscienceKarolinska InstitutetStockholmSE‐171 77Sweden
| | - Susanne Löffler
- AIMES – Center for the Advancement of Integrated Medical and Engineering Sciences at Karolinska Institutet and KTH Royal Institute of TechnologyStockholmSE‐171 77Sweden
- Department of NeuroscienceKarolinska InstitutetStockholmSE‐171 77Sweden
| | - Agneta Richter‐Dahlfors
- AIMES – Center for the Advancement of Integrated Medical and Engineering Sciences at Karolinska Institutet and KTH Royal Institute of TechnologyStockholmSE‐171 77Sweden
- Department of NeuroscienceKarolinska InstitutetStockholmSE‐171 77Sweden
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Wang L, Liu H. Microbial electrosynthesis of single cell protein and methane by coupling fast-growing Methanococcus maripaludis with microbial electrolysis cells. BIORESOURCE TECHNOLOGY 2024; 393:130025. [PMID: 37972904 DOI: 10.1016/j.biortech.2023.130025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Revised: 11/13/2023] [Accepted: 11/13/2023] [Indexed: 11/19/2023]
Abstract
Single cell protein (SCP) is a promising alternative protein source, as its production bypasses the disadvantages of animal protein production in industrial agriculture. Coupling a fast-growing hydrogen consuming organism with microbial electrolysis cells (MECs) could be a viable method for SCP production. In this study, a fast-growing and protein-rich methanogen, Methanococcus maripaludis was selected as the primary SCP source. The inoculation of M. maripaludis in MECs triggered cell synthesis with methane production. The doubling time measured was 11.2 h and the specific growth rate was 0.062 1/h. The highest SCP production rate was 13.7 mg/L/h. In the dried biomass, the weight of protein was over 60 %. Amino acid profiling of the harvested biomass demonstrated high abundance of essential amino acids. The electron flux analysis indicated that 31.3 % electrons in the electrochemical systems were directed into SCP synthesis. These results illustrated the potential for SCP production by coupling a fast-growing methanogen with MECs.
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Affiliation(s)
- Luguang Wang
- Department of Biological and Ecological Engineering, Oregon State University, Corvallis, OR 97331, United States; Department of Biological Engineering, Utah State University, Logan, UT 84322, United States
| | - Hong Liu
- Department of Biological and Ecological Engineering, Oregon State University, Corvallis, OR 97331, United States.
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3
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Burgoyne ED, Molina-Osorio AF, Moshrefi R, Shanahan R, McGlacken GP, Stockmann TJ, Scanlon MD. Detection of Pseudomonas aeruginosa quorum sensing molecules at an electrified liquid|liquid micro-interface through facilitated proton transfer. Analyst 2021; 145:7000-7008. [PMID: 32869782 DOI: 10.1039/d0an01245a] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Miniaturization of electrochemical detection methods for point-of-care-devices is ideal for their integration and use within healthcare environments. Simultaneously, the prolific pathogenic bacteria Pseudomonas aeruginosa poses a serious health risk to patients with compromised immune systems. Recognizing these two factors, a proof-of-concept electrochemical method employing a micro-interface between water and oil (w/o) held at the tip of a pulled borosilicate glass capillary is presented. This method targets small molecules produced by P. aeruginosa colonies as signalling factors that control colony growth in a pseudo-multicellular process known as quorum sensing (QS). The QS molecules of interest are 4-hydroxy-2-heptylquinoline (HHQ) and 2-heptyl-3,4-dihydroxyquinoline (PQS, Pseudomonas quinolone signal). Hydrophobic HHQ and PQS molecules, dissolved in the oil phase, were observed electrochemically to facilitate proton transfer across the w/o interface. This interfacial complexation can be exploited as a facile electrochemical detection method for P. aeruginosa and is advantageous as it does not depend on the redox activity of HHQ/PQS. Interestingly, the limit-of-linearity is reached as [H+] ≈ [ligand]. Density functional theory calculations were performed to determine the proton affinities and gas-phase basicities of HHQ/PQS, as well as elucidate the likely site of stepwise protonation within each molecule.
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Affiliation(s)
- Edward D Burgoyne
- The Bernal Institute and Department of Chemical Sciences, School of Natural Sciences, University of Limerick (UL), Limerick V94 T9PX, Ireland.
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Cai YM. Non-surface Attached Bacterial Aggregates: A Ubiquitous Third Lifestyle. Front Microbiol 2020; 11:557035. [PMID: 33343514 PMCID: PMC7746683 DOI: 10.3389/fmicb.2020.557035] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 11/13/2020] [Indexed: 01/03/2023] Open
Abstract
Bacteria are now generally believed to adopt two main lifestyles: planktonic individuals, or surface-attached biofilms. However, in recent years medical microbiologists started to stress that suspended bacterial aggregates are a major form of bacterial communities in chronic infection sites. Despite sharing many similarities with surface-attached biofilms and are thus generally defined as biofilm-like aggregates, these non-attached clumps of cells in vivo show much smaller sizes and different formation mechanisms. Furthermore, ex vivo clinical isolates were frequently reported to be less attached to abiotic surfaces when compared to standard type strains. While this third lifestyle is starting to draw heavy attention in clinical studies, it has a long history in natural and environmental sciences. For example, marine gel particles formed by bacteria attachment to phytoplankton exopolymers have been well documented in oceans; large river and lake snows loaded with bacterial aggregates are frequently found in freshwater systems; multispecies bacterial "flocs" have long been used in wastewater treatment. This review focuses on non-attached aggregates found in a variety of natural and clinical settings, as well as some recent technical developments facilitating aggregate research. The aim is to summarise the characteristics of different types of bacterial aggregates, bridging the knowledge gap, provoking new perspectives for researchers from different fields, and highlighting the importance of more research input in this third lifestyle of bacteria closely relevant to our daily life.
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Affiliation(s)
- Yu-Ming Cai
- National Biofilms Innovation Centre, Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
- Biological Sciences, Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
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5
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Digital Proxy of a Bio-Reactor (DIYBOT) combines sensor data and data analytics to improve greywater treatment and wastewater management systems. Sci Rep 2020; 10:8015. [PMID: 32415099 PMCID: PMC7229150 DOI: 10.1038/s41598-020-64789-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 04/14/2020] [Indexed: 02/01/2023] Open
Abstract
Technologies to treat wastewater in decentralized systems are critical for sustainable development. Bioreactors are suitable for low-energy removal of inorganic and organic compounds, particularly for non-potable applications where a small footprint is required. One of the main problems associated with bioreactor use is sporadic spikes of chemical toxins, including nanoparticles. Here, we describe the development of DIYBOT (Digital Proxy of a Bio-Reactor), which enables remote monitoring of bioreactors and uses the data to inform decisions related to systems management. To test DIYBOT, a household-scale membrane aerated bioreactor with real-time water quality sensors was used to treat household greywater simulant. After reaching steady-state, silver nanoparticles (AgNP) representative of the mixture found in laundry wastewater were injected into the system to represent a chemical contamination. Measurements of carbon metabolism, effluent water quality, biofilm sloughing rate, and microbial diversity were characterized after nanoparticle exposure. Real-time sensor data were analyzed to reconstruct phase-space dynamics and extrapolate a phenomenological digital proxy to evaluate system performance. The management implication of the stable-focus dynamics, reconstructed from observed data, is that the bioreactor self-corrects in response to contamination spikes at AgNP levels below 2.0 mg/L. DIYBOT may help reduce the frequency of human-in-the-loop corrective management actions for wastewater processing.
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Gordeev AA, Chetverin AB. Methods for Screening Live Cells. BIOCHEMISTRY (MOSCOW) 2018; 83:S81-S102. [DOI: 10.1134/s0006297918140080] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Vávrová A, Matoulková D, Balážová T, Šedo O. MALDI-TOF MS Analysis of Anaerobic Bacteria Isolated from Biofilm-Covered Surfaces in Brewery Bottling Halls. JOURNAL OF THE AMERICAN SOCIETY OF BREWING CHEMISTS 2018. [DOI: 10.1094/asbcj-2014-0324-01] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Andrea Vávrová
- Section of Microbiology, Department of Experimental Biology, Faculty of Science, Masaryk University, Tvrdého 14, 602 00 Brno, Czech Republic
| | - Dagmar Matoulková
- Department of Microbiology, Research Institute of Brewing and Malting, Plc., Lípová 15, 120 44 Prague 2, Czech Republic
| | - Tereza Balážová
- Section of Microbiology, Department of Experimental Biology, Faculty of Science, Masaryk University, Tvrdého 14, 602 00 Brno, Czech Republic
- Research Group Proteomics, CEITEC, Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Ondrej Šedo
- Research Group Proteomics, CEITEC, Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic
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Townsend EM, Sherry L, Rajendran R, Hansom D, Butcher J, Mackay WG, Williams C, Ramage G. Development and characterisation of a novel three-dimensional inter-kingdom wound biofilm model. BIOFOULING 2016; 32:1259-1270. [PMID: 27841027 DOI: 10.1080/08927014.2016.1252337] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 10/19/2016] [Indexed: 06/06/2023]
Abstract
Chronic diabetic foot ulcers are frequently colonised and infected by polymicrobial biofilms that ultimately prevent healing. This study aimed to create a novel in vitro inter-kingdom wound biofilm model on complex hydrogel-based cellulose substrata to test commonly used topical wound treatments. Inter-kingdom triadic biofilms composed of Candida albicans, Pseudomonas aeruginosa, and Staphylococcus aureus were shown to be quantitatively greater in this model compared to a simple substratum when assessed by conventional culture, metabolic dye and live dead qPCR. These biofilms were both structurally complex and compositionally dynamic in response to topical therapy, so when treated with either chlorhexidine or povidone iodine, principal component analysis revealed that the 3-D cellulose model was minimally impacted compared to the simple substratum model. This study highlights the importance of biofilm substratum and inclusion of relevant polymicrobial and inter-kingdom components, as these impact penetration and efficacy of topical antiseptics.
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Affiliation(s)
- Eleanor M Townsend
- a Oral Sciences Research Group, Glasgow Dental School, School of Medicine, Dentistry and Nursing, College of Medical, Veterinary and Life Sciences , University of Glasgow , Glasgow , UK
- b Institute of Healthcare Policy and Practice , University of West of Scotland , Paisley , UK
| | - Leighann Sherry
- a Oral Sciences Research Group, Glasgow Dental School, School of Medicine, Dentistry and Nursing, College of Medical, Veterinary and Life Sciences , University of Glasgow , Glasgow , UK
- b Institute of Healthcare Policy and Practice , University of West of Scotland , Paisley , UK
| | - Ranjith Rajendran
- a Oral Sciences Research Group, Glasgow Dental School, School of Medicine, Dentistry and Nursing, College of Medical, Veterinary and Life Sciences , University of Glasgow , Glasgow , UK
| | - Donald Hansom
- a Oral Sciences Research Group, Glasgow Dental School, School of Medicine, Dentistry and Nursing, College of Medical, Veterinary and Life Sciences , University of Glasgow , Glasgow , UK
| | - John Butcher
- b Institute of Healthcare Policy and Practice , University of West of Scotland , Paisley , UK
| | - William G Mackay
- b Institute of Healthcare Policy and Practice , University of West of Scotland , Paisley , UK
| | - Craig Williams
- b Institute of Healthcare Policy and Practice , University of West of Scotland , Paisley , UK
| | - Gordon Ramage
- a Oral Sciences Research Group, Glasgow Dental School, School of Medicine, Dentistry and Nursing, College of Medical, Veterinary and Life Sciences , University of Glasgow , Glasgow , UK
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Ramasamy M, Lee J. Recent Nanotechnology Approaches for Prevention and Treatment of Biofilm-Associated Infections on Medical Devices. BIOMED RESEARCH INTERNATIONAL 2016; 2016:1851242. [PMID: 27872845 PMCID: PMC5107826 DOI: 10.1155/2016/1851242] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 10/13/2016] [Indexed: 11/23/2022]
Abstract
Bacterial colonization in the form of biofilms on surfaces causes persistent infections and is an issue of considerable concern to healthcare providers. There is an urgent need for novel antimicrobial or antibiofilm surfaces and biomedical devices that provide protection against biofilm formation and planktonic pathogens, including antibiotic resistant strains. In this context, recent developments in the material science and engineering fields and steady progress in the nanotechnology field have created opportunities to design new biomaterials and surfaces with anti-infective, antifouling, bactericidal, and antibiofilm properties. Here we review a number of the recently developed nanotechnology-based biomaterials and explain underlying strategies used to make antibiofilm surfaces.
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Affiliation(s)
| | - Jintae Lee
- School of Chemical Engineering, Yeungnam University, Gyeongsan 38541, Republic of Korea
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10
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Cheng L, House MW, Weiss WJ, Banks MK. Monitoring sulfide-oxidizing biofilm activity on cement surfaces using non-invasive self-referencing microsensors. WATER RESEARCH 2016; 89:321-329. [PMID: 26707733 DOI: 10.1016/j.watres.2015.11.066] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 08/15/2015] [Accepted: 11/28/2015] [Indexed: 06/05/2023]
Abstract
Microbially influenced corrosion (MIC) in concrete results in significant cost for infrastructure maintenance. Prior studies have employed molecular techniques to identify microbial community species in corroded concrete, but failed to explore bacterial activity and functionality during deterioration. In this study, biofilms of different sulfur-oxidizing bacteria compositions were developed on the surface of cement paste samples to simulate the natural ecological succession of microbial communities during MIC processes. Noninvasive, self-referencing (SR) microsensors were used to quantify real time changes of oxygen, hydrogen ion and calcium ion flux for the biofilm to provide more information about bacterial behavior during deterioration. Results showed higher transport rates in oxygen consumption, and hydrogen ion at 4 weeks than 2 weeks, indicating increased bacterial activity over time. Samples with five species biofilm had the highest hydrogen ion and calcium ion transport rates, confirming attribution of acidophilic sulfur-oxidizing microorganisms (ASOM). Differences in transport rates between three species samples and two species samples confirmed the diversity between Thiomonas intermedia and Starkeya novella. The limitations of SR sensors in corrosion application could be improved in future studies when combined with molecular techniques to identify the roles of major bacterial species in the deterioration process.
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Affiliation(s)
- Liqiu Cheng
- Zachry Department of Civil Engineering, Texas A&M University, 3136 TAMU, College Station, TX 77843-3136, USA.
| | - Mitch W House
- Lyles School of Civil Engineering, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47907-2051, USA
| | - W Jason Weiss
- Lyles School of Civil Engineering, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47907-2051, USA; Bindley Bioscience Center, Physiological Sensing Facility, Discovery Park, Purdue University, 1203 W. State Street, West Lafayette, IN 47907-2057, USA
| | - M Katherine Banks
- Zachry Department of Civil Engineering, Texas A&M University, 3136 TAMU, College Station, TX 77843-3136, USA
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Cullen L, Weiser R, Olszak T, Maldonado RF, Moreira AS, Slachmuylders L, Brackman G, Paunova-Krasteva TS, Zarnowiec P, Czerwonka G, Reilly J, Drevinek P, Kaca W, Melter O, De Soyza A, Perry A, Winstanley C, Stoitsova SR, Lavigne R, Mahenthiralingam E, Sá-Correia I, Coenye T, Drulis-Kawa Z, Augustyniak D, Valvano MA, McClean S. Phenotypic characterization of an international Pseudomonas aeruginosa reference panel: strains of cystic fibrosis (CF) origin show less in vivo virulence than non-CF strains. MICROBIOLOGY-SGM 2015; 161:1961-1977. [PMID: 26253522 DOI: 10.1099/mic.0.000155] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Pseudomonas aeruginosa causes chronic lung infections in people with cystic fibrosis (CF) and acute opportunistic infections in people without CF. Forty-two P. aeruginosa strains from a range of clinical and environmental sources were collated into a single reference strain panel to harmonise research on this diverse opportunistic pathogen. To facilitate further harmonized and comparable research on P. aeruginosa, we characterized the panel strains for growth rates, motility, virulence in the Galleria mellonella infection model, pyocyanin and alginate production, mucoid phenotype, LPS pattern, biofilm formation, urease activity, and antimicrobial and phage susceptibilities. Phenotypic diversity across the P. aeruginosa panel was apparent for all phenotypes examined, agreeing with the marked variability seen in this species. However, except for growth rate, the phenotypic diversity among strains from CF versus non-CF sources was comparable. CF strains were less virulent in the G. mellonella model than non-CF strains (P = 0.037). Transmissible CF strains generally lacked O-antigen, produced less pyocyanin and had low virulence in G. mellonella. Furthermore, in the three sets of sequential CF strains, virulence, O-antigen expression and pyocyanin production were higher in the earlier isolate compared to the isolate obtained later in infection. Overall, this full phenotypic characterization of the defined panel of P. aeruginosa strains increases our understanding of the virulence and pathogenesis of P. aeruginosa and may provide a valuable resource for the testing of novel therapies against this problematic pathogen.
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Affiliation(s)
- Louise Cullen
- Centre of Microbial Host Interactions, Institute of Technology Tallaght, Tallaght, Dublin 24, Ireland
| | - Rebecca Weiser
- Cardiff School of Biosciences, Cardiff University, Cardiff, UK
| | - Tomasz Olszak
- Institute of Genetics and Microbiology, University of Wroclaw, Wroclaw, Poland
| | - Rita F Maldonado
- IBB - Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
| | - Ana S Moreira
- IBB - Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
| | - Lisa Slachmuylders
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Gilles Brackman
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | | | - Paulina Zarnowiec
- Department of Microbiology, Jan Kochanowski University in Kielce, Kielce, Poland
| | - Grzegorz Czerwonka
- Department of Microbiology, Jan Kochanowski University in Kielce, Kielce, Poland
| | - James Reilly
- Centre of Microbial Host Interactions, Institute of Technology Tallaght, Tallaght, Dublin 24, Ireland
| | - Pavel Drevinek
- Department of Medical Microbiology, Motol University Hospital & 2nd Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Wieslaw Kaca
- Department of Microbiology, Jan Kochanowski University in Kielce, Kielce, Poland
| | - Oto Melter
- Department of Medical Microbiology, Motol University Hospital & 2nd Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Anthony De Soyza
- Institute of Cellular Medicine, Newcastle University & Bronchiectasis Service, Freeman Hospital Newcastle, Newcastle-upon-Tyne, UK
| | - Audrey Perry
- Department of Clinical Microbiology, Freeman Hospital Newcastle, Newcastle-upon-Tyne, UK
| | - Craig Winstanley
- Institute for Infection and Global Health, University of Liverpool, Liverpool, UK
| | - Stoyanka R Stoitsova
- Institute of Microbiology, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 26, Sofia 1113, Bulgaria
| | - Rob Lavigne
- Laboratory of Gene Technology, KU Leuven, Leuven, Belgium
| | | | - Isabel Sá-Correia
- IBB - Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
| | - Tom Coenye
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Zuzanna Drulis-Kawa
- Institute of Genetics and Microbiology, University of Wroclaw, Wroclaw, Poland
| | - Daria Augustyniak
- Institute of Genetics and Microbiology, University of Wroclaw, Wroclaw, Poland
| | - Miguel A Valvano
- Centre for Infection and Immunity, School of Medicine, Dentistry and Biomedical Sciences, Queen's University, Belfast, UK
| | - Siobhán McClean
- Centre of Microbial Host Interactions, Institute of Technology Tallaght, Tallaght, Dublin 24, Ireland
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Lewis CL, Craig CC, Senecal AG. Mass and density measurements of live and dead Gram-negative and Gram-positive bacterial populations. Appl Environ Microbiol 2014; 80:3622-31. [PMID: 24705320 PMCID: PMC4054131 DOI: 10.1128/aem.00117-14] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 03/31/2014] [Indexed: 12/16/2022] Open
Abstract
Monitoring cell growth and measuring physical features of food-borne pathogenic bacteria are important for better understanding the conditions under which these organisms survive and proliferate. To address this challenge, buoyant masses of live and dead Escherichia coli O157:H7 and Listeria innocua were measured using Archimedes, a commercially available suspended microchannel resonator (SMR). Cell growth was monitored with Archimedes by observing increased cell concentration and buoyant mass values of live growing bacteria. These growth data were compared to optical density measurements obtained with a Bioscreen system. We observed buoyant mass measurements with Archimedes at cell concentrations between 10(5) and 10(8) cells/ml, while growth was not observed with optical density measurements until the concentration was 10(7) cells/ml. Buoyant mass measurements of live and dead cells with and without exposure to hydrogen peroxide stress were also compared; live cells generally had a larger buoyant mass than dead cells. Additionally, buoyant mass measurements were used to determine cell density and total mass for both live and dead cells. Dead E. coli cells were found to have a larger density and smaller total mass than live E. coli cells. In contrast, density was the same for both live and dead L. innocua cells, while the total mass was greater for live than for dead cells. These results contribute to the ongoing challenge to further develop existing technologies used to observe cell populations at low concentrations and to measure unique physical features of cells that may be useful for developing future diagnostics.
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