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Ghosh R, Arnheim A, van Zee M, Shang L, Soemardy C, Tang RC, Mellody M, Baghdasarian S, Sanchez Ochoa E, Ye S, Chen S, Williamson C, Karunaratne A, Di Carlo D. Lab on a Particle Technologies. Anal Chem 2024; 96:7817-7839. [PMID: 38650433 PMCID: PMC11112544 DOI: 10.1021/acs.analchem.4c01510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 04/14/2024] [Accepted: 04/16/2024] [Indexed: 04/25/2024]
Affiliation(s)
- Rajesh Ghosh
- Department
of Bioengineering, University of California,
Los Angeles, Los Angeles, California 90095, United States
| | - Alyssa Arnheim
- Department
of Bioengineering, University of California,
Los Angeles, Los Angeles, California 90095, United States
| | - Mark van Zee
- Department
of Bioengineering, University of California,
Los Angeles, Los Angeles, California 90095, United States
| | - Lily Shang
- Department
of Bioengineering, University of California,
Los Angeles, Los Angeles, California 90095, United States
| | - Citradewi Soemardy
- Department
of Bioengineering, University of California,
Los Angeles, Los Angeles, California 90095, United States
| | - Rui-Chian Tang
- Department
of Bioengineering, University of California,
Los Angeles, Los Angeles, California 90095, United States
| | - Michael Mellody
- Department
of Bioengineering, University of California,
Los Angeles, Los Angeles, California 90095, United States
| | - Sevana Baghdasarian
- Department
of Bioengineering, University of California,
Los Angeles, Los Angeles, California 90095, United States
| | - Edwin Sanchez Ochoa
- Department
of Bioengineering, University of California,
Los Angeles, Los Angeles, California 90095, United States
| | - Shun Ye
- Department
of Bioengineering, University of California,
Los Angeles, Los Angeles, California 90095, United States
| | - Siyu Chen
- Department
of Bioengineering, University of California,
Los Angeles, Los Angeles, California 90095, United States
| | - Cayden Williamson
- Department
of Bioengineering, University of California,
Los Angeles, Los Angeles, California 90095, United States
| | - Amrith Karunaratne
- Department
of Bioengineering, University of California,
Los Angeles, Los Angeles, California 90095, United States
| | - Dino Di Carlo
- Department
of Bioengineering, University of California,
Los Angeles, Los Angeles, California 90095, United States
- Jonsson
Comprehensive Cancer Center, University
of California, Los Angeles, Los Angeles, California 90095, United States
- Department
of Mechanical and Aerospace Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
- California
NanoSystems Institute, Los Angeles, California 90095, United States
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2
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Kotliarevski L, Mani KA, Feldbaum RA, Yaakov N, Belausov E, Zelinger E, Ment D, Mechrez G. Single-Conidium Encapsulation in Oil-in-Water Pickering Emulsions at High Encapsulation Yield. Front Chem 2021; 9:726874. [PMID: 34912776 PMCID: PMC8666500 DOI: 10.3389/fchem.2021.726874] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 11/10/2021] [Indexed: 12/02/2022] Open
Abstract
This study presents an individual encapsulation of fungal conidia in an oil-in-water Pickering emulsion at a single-conidium encapsulation yield of 44%. The single-conidium encapsulation yield was characterized by analysis of confocal microscopy micrographs. Mineral oil-in-water emulsions stabilized by amine-functionalized titania dioxide (TiO2-NH2 or titania-NH2) particles were prepared. The structure and the stability of the emulsions were investigated at different compositions by confocal microscopy and a LUMiSizer® respectively. The most stable emulsions with a droplet size suitable for single-conidium encapsulation were further studied for their individual encapsulation capabilities. The yields of individual encapsulation in the emulsions; i.e., the number of conidia that were individually encapsulated out of the total number of conidia, were characterized by confocal microscopy assay. This rapid, easy to use approach to single-conidium encapsulation, which generates a significantly high yield with eco-friendly titania-based emulsions, only requires commonly used emulsification and agitation methods.
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Affiliation(s)
- Liliya Kotliarevski
- Department of Food Sciences, Institute of Postharvest and Food Sciences, Agricultural Research Organization (ARO), Volcani Institute, Rishon Lezion, Israel.,Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Karthik Ananth Mani
- Department of Food Sciences, Institute of Postharvest and Food Sciences, Agricultural Research Organization (ARO), Volcani Institute, Rishon Lezion, Israel.,Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Reut Amar Feldbaum
- Department of Food Sciences, Institute of Postharvest and Food Sciences, Agricultural Research Organization (ARO), Volcani Institute, Rishon Lezion, Israel
| | - Noga Yaakov
- Department of Food Sciences, Institute of Postharvest and Food Sciences, Agricultural Research Organization (ARO), Volcani Institute, Rishon Lezion, Israel
| | - Eduard Belausov
- Department of Ornamental Plants and Agricultural Biotechnology, Institute of Plant Science, Agricultural Research Organization (ARO), Volcani Institute, Rishon Lezion, Israel
| | - Einat Zelinger
- Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Dana Ment
- Department of Plant Pathology and Weed Research, Institute of Plant Protection, Agricultural Research Organization (ARO), Volcani Institute, Rishon Lezion, Israel
| | - Guy Mechrez
- Department of Food Sciences, Institute of Postharvest and Food Sciences, Agricultural Research Organization (ARO), Volcani Institute, Rishon Lezion, Israel
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Molloy A, Harrison J, McGrath JS, Owen Z, Smith C, Liu X, Li X, Cox JAG. Microfluidics as a Novel Technique for Tuberculosis: From Diagnostics to Drug Discovery. Microorganisms 2021; 9:microorganisms9112330. [PMID: 34835455 PMCID: PMC8618277 DOI: 10.3390/microorganisms9112330] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 11/01/2021] [Accepted: 11/03/2021] [Indexed: 12/29/2022] Open
Abstract
Tuberculosis (TB) remains a global healthcare crisis, with an estimated 5.8 million new cases and 1.5 million deaths in 2020. TB is caused by infection with the major human pathogen Mycobacterium tuberculosis, which is difficult to rapidly diagnose and treat. There is an urgent need for new methods of diagnosis, sufficient in vitro models that capably mimic all physiological conditions of the infection, and high-throughput drug screening platforms. Microfluidic-based techniques provide single-cell analysis which reduces experimental time and the cost of reagents, and have been extremely useful for gaining insight into monitoring microorganisms. This review outlines the field of microfluidics and discusses the use of this novel technique so far in M. tuberculosis diagnostics, research methods, and drug discovery platforms. The practices of microfluidics have promising future applications for diagnosing and treating TB.
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Affiliation(s)
- Antonia Molloy
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK; (A.M.); (J.H.)
| | - James Harrison
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK; (A.M.); (J.H.)
| | - John S. McGrath
- Sphere Fluidics Limited, The McClintock Building, Suite 7, Granta Park, Great Abington, Cambridge CB21 6GP, UK; (J.S.M.); (Z.O.); (C.S.); (X.L.); (X.L.)
| | - Zachary Owen
- Sphere Fluidics Limited, The McClintock Building, Suite 7, Granta Park, Great Abington, Cambridge CB21 6GP, UK; (J.S.M.); (Z.O.); (C.S.); (X.L.); (X.L.)
| | - Clive Smith
- Sphere Fluidics Limited, The McClintock Building, Suite 7, Granta Park, Great Abington, Cambridge CB21 6GP, UK; (J.S.M.); (Z.O.); (C.S.); (X.L.); (X.L.)
| | - Xin Liu
- Sphere Fluidics Limited, The McClintock Building, Suite 7, Granta Park, Great Abington, Cambridge CB21 6GP, UK; (J.S.M.); (Z.O.); (C.S.); (X.L.); (X.L.)
| | - Xin Li
- Sphere Fluidics Limited, The McClintock Building, Suite 7, Granta Park, Great Abington, Cambridge CB21 6GP, UK; (J.S.M.); (Z.O.); (C.S.); (X.L.); (X.L.)
| | - Jonathan A. G. Cox
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK; (A.M.); (J.H.)
- Correspondence: ; Tel.: +44-121-204-5011
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4
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Barr DA, Omollo C, Mason M, Koch A, Wilkinson RJ, Lalloo DG, Meintjes G, Mizrahi V, Warner DF, Davies G. Flow cytometry method for absolute counting and single-cell phenotyping of mycobacteria. Sci Rep 2021; 11:18661. [PMID: 34545154 PMCID: PMC8452731 DOI: 10.1038/s41598-021-98176-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 08/30/2021] [Indexed: 11/25/2022] Open
Abstract
Detection and accurate quantitation of viable Mycobacterium tuberculosis is fundamental to understanding mycobacterial pathogenicity, tuberculosis (TB) disease progression and outcomes; TB transmission; drug action, efficacy and drug resistance. Despite this importance, methods for determining numbers of viable bacilli are limited in accuracy and precision owing to inherent characteristics of mycobacterial cell biology—including the tendency to clump, and “differential” culturability—and technical challenges consequent on handling an infectious pathogen under biosafe conditions. We developed an absolute counting method for mycobacteria in liquid cultures using a bench-top flow cytometer, and the low-cost fluorescent dyes Calcein-AM (CA) and SYBR-gold (SG). During exponential growth CA + cell counts are highly correlated with CFU counts and can be used as a real-time alternative to simplify the accurate standardisation of inocula for experiments. In contrast to CFU counting, this method can detect and enumerate cell aggregates in samples, which we show are a potential source of variance and bias when using established methods. We show that CFUs comprise a sub-population of intact, metabolically active mycobacterial cells in liquid cultures, with CFU-proportion varying by growth conditions. A pharmacodynamic application of the flow cytometry method, exploring kinetics of fluorescent probe defined subpopulations compared to CFU is demonstrated. Flow cytometry derived Mycobacterium bovis bacillus Calmette-Guérin (BCG) time-kill curves differ for rifampicin and kanamycin versus isoniazid and ethambutol, as do the relative dynamics of discrete morphologically-distinct subpopulations of bacilli revealed by this high-throughput single-cell technique.
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Affiliation(s)
- David A Barr
- Wellcome Centre for Infectious Diseases Research in Africa (CIDRI-Africa), Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, Cape Town, 7925, South Africa. .,Institute of Infection and Global Health, University of Liverpool, Liverpool, L7 3EA, UK. .,Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
| | - Charles Omollo
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence for Biomedical TB Research, Institute of Infectious Disease and Molecular Medicine, Division of Medical Microbiology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Mandy Mason
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence for Biomedical TB Research, Institute of Infectious Disease and Molecular Medicine, Division of Medical Microbiology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Anastasia Koch
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence for Biomedical TB Research, Institute of Infectious Disease and Molecular Medicine, Division of Medical Microbiology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Robert J Wilkinson
- Wellcome Centre for Infectious Diseases Research in Africa (CIDRI-Africa), Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, Cape Town, 7925, South Africa.,Department of Medicine, University of Cape Town, Cape Town, South Africa.,The Francis Crick Institute, London, NW11AT, UK.,Department of Medicine, Imperial College, London, W12 0NN, UK
| | - David G Lalloo
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Graeme Meintjes
- Wellcome Centre for Infectious Diseases Research in Africa (CIDRI-Africa), Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, Cape Town, 7925, South Africa.,Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Valerie Mizrahi
- Wellcome Centre for Infectious Diseases Research in Africa (CIDRI-Africa), Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, Cape Town, 7925, South Africa.,SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence for Biomedical TB Research, Institute of Infectious Disease and Molecular Medicine, Division of Medical Microbiology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Digby F Warner
- Wellcome Centre for Infectious Diseases Research in Africa (CIDRI-Africa), Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, Cape Town, 7925, South Africa.,SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence for Biomedical TB Research, Institute of Infectious Disease and Molecular Medicine, Division of Medical Microbiology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Gerry Davies
- Institute of Infection and Global Health, University of Liverpool, Liverpool, L7 3EA, UK
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5
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Rampacci E, Stefanetti V, Passamonti F, Henao-Tamayo M. Preclinical Models of Nontuberculous Mycobacteria Infection for Early Drug Discovery and Vaccine Research. Pathogens 2020; 9:E641. [PMID: 32781698 PMCID: PMC7459799 DOI: 10.3390/pathogens9080641] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/03/2020] [Accepted: 08/04/2020] [Indexed: 12/11/2022] Open
Abstract
Nontuberculous mycobacteria (NTM) represent an increasingly prevalent etiology of soft tissue infections in animals and humans. NTM are widely distributed in the environment and while, for the most part, they behave as saprophytic organisms, in certain situations, they can be pathogenic, so much so that the incidence of NTM infections has surpassed that of Mycobacterium tuberculosis in developed countries. As a result, a growing body of the literature has focused attention on the critical role that drug susceptibility tests and infection models play in the design of appropriate therapeutic strategies against NTM diseases. This paper is an overview of the in vitro and in vivo models of NTM infection employed in the preclinical phase for early drug discovery and vaccine development. It summarizes alternative methods, not fully explored, for the characterization of anti-mycobacterial compounds.
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Affiliation(s)
- Elisa Rampacci
- Department of Veterinary Medicine, University of Perugia, Via San Costanzo 4, 06126 Perugia, Italy; (E.R.); (V.S.)
| | - Valentina Stefanetti
- Department of Veterinary Medicine, University of Perugia, Via San Costanzo 4, 06126 Perugia, Italy; (E.R.); (V.S.)
| | - Fabrizio Passamonti
- Department of Veterinary Medicine, University of Perugia, Via San Costanzo 4, 06126 Perugia, Italy; (E.R.); (V.S.)
| | - Marcela Henao-Tamayo
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO 80523, USA;
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7
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Lam T, Brennan MD, Morrison DA, Eddington DT. Femtoliter droplet confinement of Streptococcus pneumoniae: bacterial genetic transformation by cell-cell interaction in droplets. LAB ON A CHIP 2019; 19:682-692. [PMID: 30657515 PMCID: PMC6487891 DOI: 10.1039/c8lc01367e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Streptococcus pneumoniae (pneumococcus), a deadly bacterial human pathogen, uses genetic transformation to gain antibiotic resistance. Genetic transformation begins when a pneumococcal strain in a transient specialized physiological state called competence, attacks and lyses another strain, releasing DNA, taking up fragments of the liberated DNA, and integrating divergent genes into its genome. While many steps of the process are known and generally understood, the precise mechanism of this natural genetic transformation is not fully understood and the current standard strategies to study it have limitations in specifically controlling and observing the process in detail. To overcome these limitations, we have developed a droplet microfluidic system for isolating individual episodes of bacterial transformation between two confined cells of pneumococcus. By encapsulating the cells in a 10 μm diameter aqueous droplet, we provide an improved experimental model of genetic transformation, as both participating cells can be identified, and the released DNA is spatially restricted near the attacking strain. Specifically, the bacterial cells, one rifampicin (R) resistant, the other novobiocin (N) and spectinomycin (S) resistant were encapsulated in droplets carried by the fluorinated oil FC-40 with 5% surfactant and allowed to carry out competence-specific attack and DNA uptake (and consequently gain antibiotic resistances) within the droplets. The droplets were then broken, and recombinants were recovered by selective plating with antibiotics. The new droplet system encapsulated 2 or more cells in a droplet with a probability up to 71%, supporting gene transfer rates comparable to standard mixtures of unconfined cells. Thus, confinement in droplets allows characterization of natural genetic transformation during a strictly defined interaction between two confined cells.
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Affiliation(s)
- Trinh Lam
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA.
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8
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Kaminski TS, Scheler O, Garstecki P. Droplet microfluidics for microbiology: techniques, applications and challenges. LAB ON A CHIP 2016; 16:2168-87. [PMID: 27212581 DOI: 10.1039/c6lc00367b] [Citation(s) in RCA: 239] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Droplet microfluidics has rapidly emerged as one of the key technologies opening up new experimental possibilities in microbiology. The ability to generate, manipulate and monitor droplets carrying single cells or small populations of bacteria in a highly parallel and high throughput manner creates new approaches for solving problems in diagnostics and for research on bacterial evolution. This review presents applications of droplet microfluidics in various fields of microbiology: i) detection and identification of pathogens, ii) antibiotic susceptibility testing, iii) studies of microbial physiology and iv) biotechnological selection and improvement of strains. We also list the challenges in the dynamically developing field and new potential uses of droplets in microbiology.
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Affiliation(s)
- Tomasz S Kaminski
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
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9
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Inturi B, Pujar GV, Purohit MN, Iyer VB, G. S. S, Kulkarni M. Design, synthesis and evaluation of diphenyl ether analogues as antitubercular agents. RSC Adv 2016. [DOI: 10.1039/c6ra19821j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We herein report the investigation of new diphenyl ethers asMycobacterium tuberculosisenoyl-acyl carrier protein reductase (InhA) inhibitors by structure-based drug design approach.
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Affiliation(s)
- Bharathkumar Inturi
- Department of Pharmaceutical Chemistry
- JSS College of Pharmacy
- Jagadguru Sri Shivarathreeshwara University
- Mysore-570015
- India
| | - Gurubasavaraj V. Pujar
- Department of Pharmaceutical Chemistry
- JSS College of Pharmacy
- Jagadguru Sri Shivarathreeshwara University
- Mysore-570015
- India
| | - Madhusudhan N. Purohit
- Department of Pharmaceutical Chemistry
- JSS College of Pharmacy
- Jagadguru Sri Shivarathreeshwara University
- Mysore-570015
- India
| | - Viswanathan B. Iyer
- Department of Pharmaceutical Chemistry
- JSS College of Pharmacy
- Jagadguru Sri Shivarathreeshwara University
- Mysore-570015
- India
| | - Sowmya G. S.
- Department of Microbiology
- JSS Medical College and Hospital
- Jagadguru Sri Shivarathreeshwara University
- Mysore-570015
- India
| | - Madhuri Kulkarni
- Department of Microbiology
- JSS Medical College and Hospital
- Jagadguru Sri Shivarathreeshwara University
- Mysore-570015
- India
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10
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Capturing and cultivating single bacterial cells in gel microdroplets to obtain near-complete genomes. Nat Protoc 2014; 9:608-21. [DOI: 10.1038/nprot.2014.034] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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11
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Eun YJ, Utada A, Copeland MF, Takeuchi S, Weibel DB. Encapsulating bacteria in agarose microparticles using microfluidics for high-throughput cell analysis and isolation. ACS Chem Biol 2011; 6:260-6. [PMID: 21142208 PMCID: PMC3060957 DOI: 10.1021/cb100336p] [Citation(s) in RCA: 144] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The high-throughput analysis and isolation of bacterial cells encapsulated in agarose microparticles using fluorescence-activated cell sorting (FACS) is described. Flow-focusing microfluidic systems were used to create monodisperse microparticles that were ∼30 μm in diameter. The dimensions of these particles made them compatible with flow cytometry and FACS, and the sensitivity of these techniques reduced the incubation time for cell replication before analyses were carried out. The small volume of the microparticles (∼1-50 pL) minimized the quantity of reagents needed for bacterial studies. This platform made it possible to screen and isolate bacteria and apply a combination of techniques to rapidly determine the target of biologically active small molecules. As a pilot study, Escherichia coli cells were encapsulated in agarose microparticles, incubated in the presence of varying concentrations of rifampicin, and analyzed using FACS. The minimum inhibitory concentration of rifampicin was determined, and spontaneous mutants that had developed resistance to the antibiotic were isolated via FACS and characterized by DNA sequencing. The β-subunit of RNA polymerase, RpoB, was confirmed as the target of rifampicin, and Q513L was the mutation most frequently observed. Using this approach, the time and quantity of antibiotics required for the isolation of mutants was reduced by 8- and 150-fold, respectively, compared to conventional microbiological techniques using nutrient agar plates. We envision that this technique will have an important impact on research in chemical biology, natural products chemistry, and the discovery and characterization of biologically active secondary metabolites.
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Affiliation(s)
- Ye-Jin Eun
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Andrew Utada
- Institute of Industrial Science, University of Tokyo, Tokyo, Japan
| | - Matthew F. Copeland
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Shoji Takeuchi
- Institute of Industrial Science, University of Tokyo, Tokyo, Japan
| | - Douglas B. Weibel
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
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12
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Gupta A, Bhakta S, Kundu S, Gupta M, Srivastava BS, Srivastava R. Fast-growing, non-infectious and intracellularly surviving drug-resistant Mycobacterium aurum: a model for high-throughput antituberculosis drug screening. J Antimicrob Chemother 2009; 64:774-81. [PMID: 19656786 DOI: 10.1093/jac/dkp279] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES Enoyl acyl-carrier-protein reductase (InhA), the primary endogenous target for isoniazid and ethionamide, is crucial to type-II fatty acid biosynthesis (FAS-II). The objectives of this study were first to generate InhA mutants of Mycobacterium aurum, secondly to characterize InhA-mediated isoniazid and ethionamide resistance mechanisms across those mutants and finally to investigate the interaction of InhA with enzymes in the FAS-II pathway in M. aurum. METHODS Spontaneous mutants were generated by isoniazid overdose and limited broth dilution, while for genetically modified mutants sense-antisense DNA technology was used. Southern hybridization and immunoprecipitation were both used to identify the InhA homologue in M. aurum. The latter method was further used to compare the level of InhA expression in M. aurum with that in corresponding mutants. Isoniazid/ethionamide susceptibility modulation was examined in vitro and ex vivo using a resazurin assay as well as by cfu counting. In addition, circular dichroism and the bacterial two-hybrid system were exploited to investigate the interaction of InhA with other enzymes of the FAS-II pathway. RESULTS A Mycobacterium tuberculosis InhA homologue was detected in M. aurum. Susceptibility to isoniazid/ethionamide was significantly altered in genetically modified mutants and simultaneously InhA was overexpressed in both spontaneous and genetically modified mutants. InhA interacts with other FAS-II enzymes of M. aurum in vivo. CONCLUSION Close resemblance of isoniazid/ethionamide action on InhA between M. tuberculosis and M. aurum further supports the use of fast-growing and intracellularly surviving drug-resistant M. aurum to substitute for highly virulent, extremely slow-growing M. tuberculosis strains in the early stage of antituberculosis inhibitor screening.
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Affiliation(s)
- Antima Gupta
- Microbiology Division, Central Drug Research Institute, Lucknow 226001, Uttar Pradesh, India.
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13
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Flow Cytometry: A Multipurpose Technology for a Wide Spectrum of Global Biosecurity Applications. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.jala.2009.03.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Flow cytometry, and its offspring-flow sorting, are extremely useful technologies for biosecurity and public health studies related to infectious disease. Applications range from environmental surveillance of pathogens to diagnosis and the development of vaccines and therapeutics for prevention and control of infectious diseases. Flow cytometers have been developed for laboratory analysis and field deployment. The current state of the art could enjoy more widespread use if instruments and data analysis were made simpler and had more automated functions, and if technology was modified to reduce biosafety concerns related to analysis and sorting of infectious organisms. The full spectrum of possible applications of flow cytometry technology to global biosecurity challenges has not yet been realized.
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14
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Walser M, Leibundgut RM, Pellaux R, Panke S, Held M. Isolation of monoclonal microcarriers colonized by fluorescent E. coli. Cytometry A 2008; 73:788-98. [PMID: 18561199 DOI: 10.1002/cyto.a.20597] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Microencapsulation gains increasing importance for processing of bacterial libraries and especially in high-throughput (HT) environments where >10(6) samples per day are studied. As a rule, a one-to-one relationship between an individual cell and analytical results is of key importance. Ideally, each microcarrier would therefore contain exactly one cell or colony. However, synthesis of larger numbers of capsules containing exactly one cell is not feasible as cells are randomly distributed during carrier-production. The dilemma is that high dilution conditions will yield a satisfactory degree of monoclonality, but also a very large fraction of empty compartments, whereas distribution under low dilution generates unacceptable numbers of polyclonal compartments for whose removal no satisfactory technologies exist. Hydrogel carriers with a volume of 35 nL were used as growth compartments for individual microbial colonies. E. coli cells expressing green fluorescent protein (GFP) were encapsulated at low dilution thereby intentionally producing a considerable amount of polyclonal microcarrieres. Empty and polyclonal microcarriers were then removed from the desired monoclonal fraction by a COPAS Plus particle analyzer. The results were compared with model predictions in order to investigate possible limitations in the analysis and sorting of monoclonal microcarriers by COPAS. Fluorescent E. coli cells (GFP) distributed randomly throughout the microcarrier population. Cells were successfully propagated to colonies in the microcarriers and enriched to 95% monoclonality by a COAPS sorter. Enrichment-efficiency was found to mainly depend on the colony diameter. With increasing colony size two contrary effects were observed: First, improved sorting efficiency due to increased fluorescence intensity and therefore higher detection efficiency, and second, deterioration of sorting efficiency due to occlusion occurring in polyclonal carriers. The combination of microencapsulation under low dilution conditions followed by HT sorting procedures is an efficient way for isolating larger amount of monoclonal carriers from bacterial libraries while concomitantly keeping the amounts of empty carriers at a moderate level.
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Affiliation(s)
- Marcel Walser
- ETH Zurich, Institute of Process Engineering, BioProcess Laboratory, Universitätsstr. 6/CAB H88, CH-8092 Zurich, Switzerland
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Boedicker JQ, Li L, Kline TR, Ismagilov RF. Detecting bacteria and determining their susceptibility to antibiotics by stochastic confinement in nanoliter droplets using plug-based microfluidics. LAB ON A CHIP 2008; 8:1265-72. [PMID: 18651067 PMCID: PMC2612531 DOI: 10.1039/b804911d] [Citation(s) in RCA: 207] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
This article describes plug-based microfluidic technology that enables rapid detection and drug susceptibility screening of bacteria in samples, including complex biological matrices, without pre-incubation. Unlike conventional bacterial culture and detection methods, which rely on incubation of a sample to increase the concentration of bacteria to detectable levels, this method confines individual bacteria into droplets nanoliters in volume. When single cells are confined into plugs of small volume such that the loading is less than one bacterium per plug, the detection time is proportional to plug volume. Confinement increases cell density and allows released molecules to accumulate around the cell, eliminating the pre-incubation step and reducing the time required to detect the bacteria. We refer to this approach as 'stochastic confinement'. Using the microfluidic hybrid method, this technology was used to determine the antibiogram - or chart of antibiotic sensitivity - of methicillin-resistant Staphylococcus aureus (MRSA) to many antibiotics in a single experiment and to measure the minimal inhibitory concentration (MIC) of the drug cefoxitin (CFX) against this strain. In addition, this technology was used to distinguish between sensitive and resistant strains of S. aureus in samples of human blood plasma. High-throughput microfluidic techniques combined with single-cell measurements also enable multiple tests to be performed simultaneously on a single sample containing bacteria. This technology may provide a method of rapid and effective patient-specific treatment of bacterial infections and could be extended to a variety of applications that require multiple functional tests of bacterial samples on reduced timescales.
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Affiliation(s)
- James Q Boedicker
- Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA
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16
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Shapiro HM, Perlmutter NG. Killer applications: Toward affordable rapid cell-based diagnostics for malaria and tuberculosis. CYTOMETRY PART B-CLINICAL CYTOMETRY 2008; 74 Suppl 1:S152-64. [DOI: 10.1002/cyto.b.20401] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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17
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Dang SM, Gerecht-Nir S, Chen J, Itskovitz-Eldor J, Zandstra PW. Controlled, scalable embryonic stem cell differentiation culture. Stem Cells 2005; 22:275-82. [PMID: 15153605 DOI: 10.1634/stemcells.22-3-275] [Citation(s) in RCA: 246] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Embryonic stem (ES) cells are of significant interest as a renewable source of therapeutically useful cells. ES cell aggregation is important for both human and mouse embryoid body (EB) formation and the subsequent generation of ES cell derivatives. Aggregation between EBs (agglomeration), however, inhibits cell growth and differentiation in stirred or high-cell-density static cultures. We demonstrate that the agglomeration of two EBs is initiated by E-cadherin-mediated cell attachment and followed by active cell migration. We report the development of a technology capable of controlling cell-cell interactions in scalable culture by the mass encapsulation of ES cells in size-specified agarose capsules. When placed in stirred-suspension bioreactors, encapsulated ES cells can be used to produce scalable quantities of hematopoietic progenitor cells in a controlled environment.
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Affiliation(s)
- Stephen M Dang
- Institute of Biomaterials and Biomedical Engineering, Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
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18
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Bauwens C, Yin T, Dang S, Peerani R, Zandstra PW. Development of a perfusion fed bioreactor for embryonic stem cell-derived cardiomyocyte generation: oxygen-mediated enhancement of cardiomyocyte output. Biotechnol Bioeng 2005; 90:452-61. [PMID: 15778986 DOI: 10.1002/bit.20445] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Cell transplantation is emerging as a promising new approach to replace scarred, nonfunctional myocardium in a diseased heart. At present, however, generating the numbers of donor cardiomyocytes required to develop and test animal models is a major limitation. Embryonic stem (ES) cells may be a promising source for therapeutic applications, potentially providing sufficient numbers of functionally relevant cells for transplantation into a variety of organs. We developed a single-step bioprocess for ES cell-derived cardiomyocyte production that enables both medium perfusion and direct monitoring and control of dissolved oxygen. Implementation of the bioprocess required combining methods to prevent ES cell aggregation (hydrogel encapsulation) and to purify for cardiomyocytes from the heterogeneous cell populations (genetic selection), with medium perfusion in a controlled bioreactor environment. We used this bioprocess to investigate the effects of oxygen on cardiomyocyte generation. Parallel vessels (250 mL culture volume) were run under normoxic (20% oxygen tension) or hypoxic (4% oxygen tension) conditions. After 14 days of differentiation (including 5 days of selection), the cardiomyocyte yield per input ES cell achieved in hypoxic vessels was 3.77 +/- 0.13, higher than has previously been reported. We have developed a bioprocess that improves the efficiency of ES cell-derived cardiomyocyte production, and allows the investigation of bioprocess parameters on ES cell-derived cardiomyogenesis. Using this system we have demonstrated that medium oxygen tension is a culture parameter that can be manipulated to improve cardiomyocyte yield.
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Affiliation(s)
- Céline Bauwens
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
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19
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Akselband Y, Cabral C, Shapiro DS, McGrath P. Rapid mycobacteria drug susceptibility testing using Gel Microdrop (GMD) Growth Assay and flow cytometry. J Microbiol Methods 2005; 62:181-97. [PMID: 16009276 DOI: 10.1016/j.mimet.2005.02.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2004] [Revised: 02/11/2005] [Accepted: 02/11/2005] [Indexed: 11/18/2022]
Abstract
Control of multi-drug-resistant tuberculosis has been hampered by the lack of simple, rapid and sensitive methods for assessing bacterial growth and antimicrobial susceptibility. Due to the increasing incidence and high frequency of mutations, it is unlikely that culture methods will disappear in the foreseeable future. Therefore, the need to modernize methods for rapid detection of viable clinical isolates, at a minimum as a gold standard, will persist. Previously, we confirmed the feasibility of using the Gel Microdrop (GMD) Growth Assay for identifying sub-populations of resistant Mycobacteria by testing different laboratory strains. Briefly, this assay format relies on encapsulating single bacterium in agarose microspheres and identifying clonogenic growth using flow cytometry and fluorescent staining. In this study, we modified the GMD Growth Assay to make it suitable for clinical applications. We demonstrated the effectiveness and safety of this novel approach for detecting drug susceptibility in clinically relevant laboratory strains as well as clinical isolates of Mycobacterium tuberculosis. Correlation between results using the GMD Growth Assay format and results using two well characterized methods (Broth Microdilution MIC and BACTEC 460TB) was 87.5% and 90%, respectively. However, due to the inherent sensitivity of flow cytometry and the ability to detect small (<1%) sub-populations of resistant mycobacteria, the GMD Growth Assay identified more cases of drug resistance. Using 4 clinically relevant mycobacterial strains, we assessed susceptibility to primary anti-tuberculosis drugs using both the Broth Microdilution MIC method and the GMD Growth Assay. We performed 24 tests on isoniazid-resistant BCG, Mycobacterium tuberculosis H37Ra and Mycobacterium avium strains. The Broth Microdilution MIC method identified 7 cases (29.1%) of resistance to INH and EMB compared to the GMD Growth Assay which identified resistance in 10 cases (41.6%); in 3 cases (12.5%), resistance to INH and EMB was detected only with the GMD Growth Assay. In addition, using 20 Mycobacterium tuberculosis clinical isolates, we compared results using BACTEC 460TB method performed by collaborators and the GMD Growth Assay. Eight of 20 (40%) clinical isolates, which were not identified as drug-resistant using the conventional BACTEC 460TB method, were resistant to 1, 2, or 3 different concentrations of drugs using the GMD Growth Assay (13 cases of 140 experiments). In one case (isolate 1879), resistance to 10.0 microg/ml of STR detected using BACTEC 460TB method was not confirmed by the GMD Growth Assay. Thus, the overall agreement between these methods was 90% (14 discrepant results of 140 experiments). These data demonstrate that the GMD Growth Assay is an accurate and sensitive method for rapid susceptibility testing of Mycobacterium tuberculosis for use in clinical reference laboratory settings.
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Affiliation(s)
- Y Akselband
- One Cell Systems, Inc., Suite 200, 100 Inman Street, Cambridge, MA 02139, United States.
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20
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Zengler K, Toledo G, Rappe M, Elkins J, Mathur EJ, Short JM, Keller M. Cultivating the uncultured. Proc Natl Acad Sci U S A 2002; 99:15681-6. [PMID: 12438682 PMCID: PMC137776 DOI: 10.1073/pnas.252630999] [Citation(s) in RCA: 602] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The recent application of molecular phylogeny to environmental samples has resulted in the discovery of an abundance of unique and previously unrecognized microorganisms. The vast majority of this microbial diversity has proved refractory to cultivation. Here, we describe a universal method that provides access to this immense reservoir of untapped microbial diversity. This technique combines encapsulation of cells in gel microdroplets for massively parallel microbial cultivation under low nutrient flux conditions, followed by flow cytometry to detect microdroplets containing microcolonies. The ability to grow and study previously uncultured organisms in pure culture will enhance our understanding of microbial physiology and metabolic adaptation and will provide new sources of microbial metabolites. We show that this technology can be applied to samples from several different environments, including seawater and soil.
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Abstract
Classical microbiology techniques are relatively slow in comparison to other analytical techniques, in many cases due to the need to culture the microorganisms. Furthermore, classical approaches are difficult with unculturable microorganisms. More recently, the emergence of molecular biology techniques, particularly those on antibodies and nucleic acid probes combined with amplification techniques, has provided speediness and specificity to microbiological diagnosis. Flow cytometry (FCM) allows single- or multiple-microbe detection in clinical samples in an easy, reliable, and fast way. Microbes can be identified on the basis of their peculiar cytometric parameters or by means of certain fluorochromes that can be used either independently or bound to specific antibodies or oligonucleotides. FCM has permitted the development of quantitative procedures to assess antimicrobial susceptibility and drug cytotoxicity in a rapid, accurate, and highly reproducible way. Furthermore, this technique allows the monitoring of in vitro antimicrobial activity and of antimicrobial treatments ex vivo. The most outstanding contribution of FCM is the possibility of detecting the presence of heterogeneous populations with different responses to antimicrobial treatments. Despite these advantages, the application of FCM in clinical microbiology is not yet widespread, probably due to the lack of access to flow cytometers or the lack of knowledge about the potential of this technique. One of the goals of this review is to attempt to mitigate this latter circumstance. We are convinced that in the near future, the availability of commercial kits should increase the use of this technique in the clinical microbiology laboratory.
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23
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Alvarez-Barrientos A, Arroyo J, Cantón R, Nombela C, Sánchez-Pérez M. Applications of flow cytometry to clinical microbiology. Clin Microbiol Rev 2000; 13:167-95. [PMID: 10755996 PMCID: PMC100149 DOI: 10.1128/cmr.13.2.167] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Classical microbiology techniques are relatively slow in comparison to other analytical techniques, in many cases due to the need to culture the microorganisms. Furthermore, classical approaches are difficult with unculturable microorganisms. More recently, the emergence of molecular biology techniques, particularly those on antibodies and nucleic acid probes combined with amplification techniques, has provided speediness and specificity to microbiological diagnosis. Flow cytometry (FCM) allows single- or multiple-microbe detection in clinical samples in an easy, reliable, and fast way. Microbes can be identified on the basis of their peculiar cytometric parameters or by means of certain fluorochromes that can be used either independently or bound to specific antibodies or oligonucleotides. FCM has permitted the development of quantitative procedures to assess antimicrobial susceptibility and drug cytotoxicity in a rapid, accurate, and highly reproducible way. Furthermore, this technique allows the monitoring of in vitro antimicrobial activity and of antimicrobial treatments ex vivo. The most outstanding contribution of FCM is the possibility of detecting the presence of heterogeneous populations with different responses to antimicrobial treatments. Despite these advantages, the application of FCM in clinical microbiology is not yet widespread, probably due to the lack of access to flow cytometers or the lack of knowledge about the potential of this technique. One of the goals of this review is to attempt to mitigate this latter circumstance. We are convinced that in the near future, the availability of commercial kits should increase the use of this technique in the clinical microbiology laboratory.
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Affiliation(s)
- A Alvarez-Barrientos
- Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, Spain
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24
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Gift EA, Weaver JC. Simultaneous quantitative determination of electroporative molecular uptake and subsequent cell survival using gel microdrops and flow cytometry. ACTA ACUST UNITED AC 2000. [DOI: 10.1002/(sici)1097-0320(20000401)39:4<243::aid-cyto1>3.0.co;2-v] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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25
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Eltringham IJ, Wilson SM, Drobniewski FA. Evaluation of a bacteriophage-based assay (phage amplified biologically assay) as a rapid screen for resistance to isoniazid, ethambutol, streptomycin, pyrazinamide, and ciprofloxacin among clinical isolates of Mycobacterium tuberculosis. J Clin Microbiol 1999; 37:3528-32. [PMID: 10523547 PMCID: PMC85685 DOI: 10.1128/jcm.37.11.3528-3532.1999] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rapid molecular assays for the detection of mutations associated with rifampin resistance in Mycobacterium tuberculosis are commercially available. However, they are complex and expensive and have predictive values of 90 to 95%. Molecular assays for other drugs are less predictive of resistance. Ideally, assays based on phenotypic markers should be used for susceptibility testing, but these can take weeks to complete. We previously described a rapid phenotypic assay, the phage amplified biologically (PhaB) assay, for the rapid determination of rifampin and isoniazid susceptibility in clinical isolates of M. tuberculosis. In this study, we extended the assay to the study of ethambutol, pyrazinamide, streptomycin, and ciprofloxacin. After the optimization of antibiotic concentrations and incubation conditions, the assay was applied to each drug for a total of 157 isolates. The correlations between the results of the PhaB assay and the resistance ratio method were 94% for isoniazid, 96% for streptomycin, 100% for ciprofloxacin, 88% for ethambutol, and 87% for pyrazinamide. For ciprofloxacin, ethambutol, and pyrazinamide, significantly better correlations were found when a 90% reduction in plaque count was used as the cutoff. Turnaround times for the PhaB assay were 2 to 3 days, compared with 10 days for the resistance ratio method. We believe that this low-cost assay may have widespread applicability for the rapid screening of drug resistance in M. tuberculosis isolates, especially in developing countries.
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Affiliation(s)
- I J Eltringham
- PHLS Mycobacterium Reference Unit, Dulwich PHL and Department of Microbiology, King's College School of Medicine and Dentistry, King's College Hospital (Dulwich), London SE22 8QF, United Kingdom.
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26
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Sánchez L, Londoño D, Arango AI, Mattar S. In vitro activity of antituberculous agents against Mycobacterium tuberculosis isolates from Bogota, DC (Colombia) evaluated by the ETest. Diagn Microbiol Infect Dis 1999; 35:109-12. [PMID: 10579090 DOI: 10.1016/s0732-8893(99)00068-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Tuberculosis tests for antimicrobial susceptibility takes weeks. However, delayed therapy, can compromise the patient, as well as lead to an increase in disease incidence. Among infectious diseases, tuberculosis continues to be a leading cause of death in the world. The E-test is a new concept for Minimal Inhibitory Concentrations (MIC) determinations for antimicrobial agents that is based on a predefined antibiotic gradient on a plastic strip calibrated with a continuous logarithmic MIC scale covering 15 two-fold dilutions. MICs of rifampin, isoniazid, and ethambutol were determined by using the E-test (AB BIODISK, Solna, Sweden) for 30 clinical strains of Mycobacterium tuberculosis isolated from four hospitals, and were compared with the Bactec method. To make the inoculum with a turbidity equivalent to a McFarland 3.0 standard, we obtained a sample from an agar surface and the Bactec 460, as described by the manufacturer. Excellent agreement (100% for rifampin, 96.8% for ethambutol, and 90% for isoniazid) was demonstrated between the E-test MIC distributions and the Bactec interpretive criteria for all clinical isolates of M. tuberculosis tested. The E-test appears to be a good alternative method for testing the susceptibility of M. tuberculosis isolates to the three, most-commonly-used therapeutic agents.
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Affiliation(s)
- L Sánchez
- Microbiology Department, Sciences Faculty, Pontificia Universidad Javeriana, Santafe de Bogota, Colombia
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27
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Collins L, Franzblau SG. Microplate alamar blue assay versus BACTEC 460 system for high-throughput screening of compounds against Mycobacterium tuberculosis and Mycobacterium avium. Antimicrob Agents Chemother 1997; 41:1004-9. [PMID: 9145860 PMCID: PMC163841 DOI: 10.1128/aac.41.5.1004] [Citation(s) in RCA: 1192] [Impact Index Per Article: 44.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
In response to the need for rapid, inexpensive, high-throughput assays for antimycobacterial drug screening, a microplate-based assay which uses Alamar blue reagent for determination of growth was evaluated. MICs of 30 antimicrobial agents against Mycobacterium tuberculosis H37Rv, M. tuberculosis H37Ra, and Mycobacterium avium were determined in the microplate Alamar blue assay (MABA) with both visual and fluorometric readings and compared to MICs determined in the BACTEC 460 system. For all three mycobacterial strains, there was < or = 1 dilution difference between MABA and BACTEC median MICs in four replicate experiments for 25 to 27 of the 30 antimicrobics. Significant differences between MABA and BACTEC MICs were observed with 0, 2, and 5 of 30 antimicrobial agents against H37Rv, H37Ra, and M. avium, respectively. Overall, MICs determined either visually or fluorometrically in MABA were highly correlated with those determined in the BACTEC 460 system, and visual MABA and fluorometric MABA MICs were highly correlated. MICs of rifampin, rifabutin, minocycline, and clarithromycin were consistently lower for H37Ra compared to H37Rv in all assays but were similar for most other drugs. M. tuberculosis H37Ra may be a suitable surrogate for the more virulent H37Rv strain in primary screening of compounds for antituberculosis activity. MABA is sensitive, rapid, inexpensive, and nonradiometric and offers the potential for screening, with or without analytical instrumentation, large numbers of antimicrobial compounds against slow-growing mycobacteria.
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Affiliation(s)
- L Collins
- Pharmacology Research Department, Gillis W. Long Hansen's Disease Center, Baton Rouge, Louisiana 70894, USA
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28
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Weaver JC, McGrath P, Adams S. Gel microdrop technology for rapid isolation of rare and high producer cells. Nat Med 1997; 3:583-5. [PMID: 9142132 DOI: 10.1038/nm0597-583] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Secreted proteins are a therapeutic cornerstone of the biotechnology industry, and numerous recombinant products, including human growth hormone, human erythropoietin and granulocyte-colony stimulating factor, are now widely prescribed. In addition to bioprocessing applications, GMD technology should benefit the emerging fields of cellular and gene therapy. The ability to assess rapidly and precisely the productivity of cells for ex vivo cell screening and expansion is a unique approach with numerous research and therapeutic uses.
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Affiliation(s)
- J C Weaver
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge 02139, USA
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29
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Davey HM, Kell DB. Flow cytometry and cell sorting of heterogeneous microbial populations: the importance of single-cell analyses. Microbiol Rev 1996; 60:641-96. [PMID: 8987359 PMCID: PMC239459 DOI: 10.1128/mr.60.4.641-696.1996] [Citation(s) in RCA: 263] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The most fundamental questions such as whether a cell is alive, in the sense of being able to divide or to form a colony, may sometimes be very hard to answer, since even axenic microbial cultures are extremely heterogeneous. Analyses that seek to correlate such things as viability, which is a property of an individual cell, with macroscopic measurements of culture variables such as ATP content, respiratory activity, and so on, must inevitably fail. It is therefore necessary to make physiological measurements on individual cells. Flow cytometry is such a technique, which allows one to analyze cells rapidly and individually and permits the quantitative analysis of microbial heterogeneity. It therefore offers many advantages over conventional measurements for both routine and more exploratory analyses of microbial properties. While the technique has been widely applied to the study of mammalian cells, is use in microbiology has until recently been much more limited, largely because of the smaller size of microbes and the consequently smaller optical signals obtainable from them. Since these technical barriers no longer hold, flow cytometry with appropriate stains has been used for the rapid discrimination and identification of microbial cells, for the rapid assessment of viability and of the heterogeneous distributions of a wealth of other more detailed physiological properties, for the analysis of antimicrobial drug-cell interactions, and for the isolation of high-yielding strains of biotechnological interest. Flow cytometric analyses provide an abundance of multivariate data, and special methods have been devised to exploit these. Ongoing advances mean that modern flow cytometers may now be used by nonspecialists to effect a renaissance in our understanding of microbial heterogeneity.
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Affiliation(s)
- H M Davey
- Institute of Biological Sciences, University of Wales, Aberystwyth, Dyfed, United Kingdom
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30
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Della-Latta P. Work Flow and Optional Protocols for Laboratories in Industrialized Countries. Clin Lab Med 1996. [DOI: 10.1016/s0272-2712(18)30261-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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31
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Gift EA, Park HJ, Paradis GA, Demain AL, Weaver JC. FACS-based isolation of slowly growing cells: double encapsulation of yeast in gel microdrops. Nat Biotechnol 1996; 14:884-7. [PMID: 9631016 DOI: 10.1038/nbt0796-884] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Isolating hyperproducing cells is important in biotechnology, but these cells usually grow slowly and can be overgrown by poorly producing cells. We describe a new method of isolating slowly growing cells from among rapidly growing cells, which has the potential for automation and high throughput (e.g., 100,000 cells/h). A model system is presented consisting of a mixed population of slowly growing mutant and rapidly growing wild-type yeast, which were encapsulated in double agarose gel microdrops (dGMDs); with most dGMDs initially containing single cells. Double encapsulation locates parent cells near dGMD centers, making microcolony measurement more accurate. After a 15-h incubation, fluorescent activated cell sorting was used to analyze and sort dGMDs with small microcolonies (slow growers) from dGMDs with large microcolonies (rapid growers). Successful isolation of slow growers from a mixed population of predominantly rapidly growing Saccharomyces cerevisiae cells was achieved.
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Affiliation(s)
- E A Gift
- Harvard-M.I.T. Division of Health Sciences and Technology, Cambridge, 02139, USA
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32
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Bownds SE, Kurzynski TA, Norden MA, Dufek JL, Schell RF. Rapid susceptibility testing for nontuberculosis mycobacteria using flow cytometry. J Clin Microbiol 1996; 34:1386-90. [PMID: 8735085 PMCID: PMC229029 DOI: 10.1128/jcm.34.6.1386-1390.1996] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
We demonstrated previously that susceptibility testing of Mycobacterium tuberculosis could be accomplished within 24 h after the organisms were incubated with antituberculosis agents by using fluorescein diacetate (FDA) staining and flow cytometry. Continued studies have now shown that assay suspensions containing M. avium, M. fortuitum, M. gordonae, or M. marinum incubated with various concentrations of ciprofloxacin, clarithromycin, erythromycin, kanamycin, rifampin, tobramycin hydrolyzed less FDA than drug-free controls. Suspensions of treated and nontreated mycobacteria could be easily differentiated at 6 and 24 h after the initiation of the susceptibility assays by using FDA staining and flow cytometry. In addition, multiplication of the mycobacteria was not required to discern differences between drug-free suspensions of mycobacteria and those treated with antimycobacterial agents. The flow cytometric assay is simple, reproducible, and rapid.
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Affiliation(s)
- S E Bownds
- Wisconsin State Laboratory of Hygiene, University of Wisconsin, Madison, 53706, USA
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Gordon S, Houldsworth S, Duncan K, Roberts IS, Andrew PW. Rapid measurement of antimycobacterial drug activity. Res Microbiol 1996; 147:79-86. [PMID: 8761727 DOI: 10.1016/0923-2508(96)80208-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- S Gordon
- Department of Microbiology and Immunology, University of Leicester, UK
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34
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Baker WR, Mitscher LA, Arain TM, Shawar R, Stover CK. Chapter 17. Recent Advances in the Chemistry and Biology of Anti-mycobacterial Agents. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 1996. [DOI: 10.1016/s0065-7743(08)60456-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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