1
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Lee SK, Baek SH, Hong MS, Lee JS, Cho EJ, Lee JI, Cho SN, Eum SY. A rapid assessing method of drug susceptibility using flow cytometry for Mycobacterium tuberculosis isolates resistant to INH, RIF and EMB. Tuberc Respir Dis (Seoul) 2022; 85:264-272. [PMID: 35196443 PMCID: PMC9263347 DOI: 10.4046/trd.2021.0134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 02/22/2022] [Indexed: 11/24/2022] Open
Abstract
Background The current conventional drug susceptibility test (DST) for Mycobacterium tuberculosis (Mtb) takes several weeks of incubation to obtain results. As a rapid method, molecular DST requires only a few days to get the results but does not fully cover the phenotypic resistance. A new rapid method based on the ability of viable Mtb bacilli to hydrolyze fluorescein diacetate to free fluorescein with detection of fluorescent mycobacteria by flow cytometric analysis, was recently developed. Methods To evaluate this cytometric method, we tested 39 clinical isolates which were susceptible or resistant to isoniazid (INH) or rifampin (RIF), or ethambutol (EMB) by phenotypic or molecular DST methods and compared the results. Results The susceptibility was determined by measuring the viability rate of Mtb and all the isolates which were tested with INH, RIF, and EMB showed susceptibility results concordant with those by the phenotypic solid and liquid media methods. The isolates having no mutations in the molecular DST but resistance in the conventional phenotypic DST were also resistant in this cytometric method. These results suggest that the flow cytometric DST method is faster than conventional agar phenotypic DST and may complement the results of molecular DST. Conclusion In conclusion, the cytometric method could provide quick and more accurate information that would help clinicians to choose more effective drugs.
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Affiliation(s)
- Sun-Kyoung Lee
- Division of Immunopathology and Cellular Immunology & Division of Microbiology, International Tuberculosis Research Center,Seoul, Republic of Korea
| | - Seung-Hun Baek
- ChangWon, Department of Microbiology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Min-Sun Hong
- Division of Immunopathology and Cellular Immunology & Division of Microbiology, International Tuberculosis Research Center,Seoul, Republic of Korea
| | - Jong-Seok Lee
- Division of Immunopathology and Cellular Immunology & Division of Microbiology, International Tuberculosis Research Center,Seoul, Republic of Korea
| | - Eun-Jin Cho
- Division of Immunopathology and Cellular Immunology & Division of Microbiology, International Tuberculosis Research Center,Seoul, Republic of Korea
| | - Ji-Im Lee
- Division of Immunopathology and Cellular Immunology & Division of Microbiology, International Tuberculosis Research Center,Seoul, Republic of Korea
| | - Sang-Nae Cho
- Division of Immunopathology and Cellular Immunology & Division of Microbiology, International Tuberculosis Research Center,Seoul, Republic of Korea.,ChangWon, Department of Microbiology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Seok-Yong Eum
- Division of Immunopathology and Cellular Immunology & Division of Microbiology, International Tuberculosis Research Center,Seoul, Republic of Korea
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2
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Campelo TA, Cardoso de Sousa PR, Nogueira LDL, Frota CC, Zuquim Antas PR. Revisiting the methods for detecting Mycobacterium tuberculosis: what has the new millennium brought thus far? Access Microbiol 2021; 3:000245. [PMID: 34595396 PMCID: PMC8479963 DOI: 10.1099/acmi.0.000245] [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: 02/23/2021] [Accepted: 06/17/2021] [Indexed: 01/07/2023] Open
Abstract
Tuberculosis (TB) affects around 10 million people worldwide in 2019. Approximately 3.4 % of new TB cases are multidrug-resistant. The gold standard method for detecting Mycobacterium tuberculosis, which is the aetiological agent of TB, is still based on microbiological culture procedures, followed by species identification and drug sensitivity testing. Sputum is the most commonly obtained clinical specimen from patients with pulmonary TB. Although smear microscopy is a low-cost and widely used method, its sensitivity is 50-60 %. Thus, owing to the need to improve the performance of current microbiological tests to provide prompt treatment, different methods with varied sensitivity and specificity for TB diagnosis have been developed. Here we discuss the existing methods developed over the past 20 years, including their strengths and weaknesses. In-house and commercial methods have been shown to be promising to achieve rapid diagnosis. Combining methods for mycobacterial detection systems demonstrates a correlation of 100 %. Other assays are useful for the simultaneous detection of M. tuberculosis species and drug-related mutations. Novel approaches have also been employed to rapidly identify and quantify total mycobacteria RNA, including assessments of global gene expression measured in whole blood to identify the risk of TB. Spoligotyping, mass spectrometry and next-generation sequencing are also promising technologies; however, their cost needs to be reduced so that low- and middle-income countries can access them. Because of the large impact of M. tuberculosis infection on public health, the development of new methods in the context of well-designed and -controlled clinical trials might contribute to the improvement of TB infection control.
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Affiliation(s)
- Thales Alves Campelo
- Faculdade de Medicina, Departamento de Patologia e Medicina Legal, Federal University of Ceará, Fortaleza, Brazil
| | | | - Lucas de Lima Nogueira
- Faculdade de Medicina, Departamento de Patologia e Medicina Legal, Federal University of Ceará, Fortaleza, Brazil
| | - Cristiane Cunha Frota
- Faculdade de Medicina, Departamento de Patologia e Medicina Legal, Federal University of Ceará, Fortaleza, Brazil
| | - Paulo Renato Zuquim Antas
- Laboratório de Imunologia Clínica, Instituto Oswaldo Cruz, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
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3
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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: 9] [Impact Index Per Article: 3.0] [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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4
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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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5
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Pina-Vaz C, Costa-de-Oliveira S, Silva-Dias A, Silva AP, Teixeira-Santos R, Rodrigues AG. Flow Cytometry in Microbiology: The Reason and the Need. ACTA ACUST UNITED AC 2017. [DOI: 10.1007/978-981-10-4499-1_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
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6
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Schell RF, Nardelli DT, DeCoster DJ, Kirk SM, Callister SM. Mycobacterium tuberculosis susceptibility testing by flow cytometry. CURRENT PROTOCOLS IN CYTOMETRY 2008; Chapter 11:Unit 11.7. [PMID: 18770792 DOI: 10.1002/0471142956.cy1107s27] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Here is another unit with clinical relevance. Tuberculosis remains a major health problem throughout the world, with approximately one-quarter of the population being infected. Rapid and accurate susceptibility testing for the tubercle bacillus is essential for control of the disease. Such testing can be accomplished by flow cytometry within twenty-four hours, instead of the days to weeks required by traditional methods. The use of flow cytometry both improves the quality of susceptibility testing and advances public health measures for the prevention and control of this ancient scourge.
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7
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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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8
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Fredricks BA, DeCoster DJ, Kim Y, Sparks N, Callister SM, Schell RF. Rapid pyrazinamide susceptibility testing of Mycobacterium tuberculosis by flow cytometry. J Microbiol Methods 2006; 67:266-72. [PMID: 16704883 DOI: 10.1016/j.mimet.2006.03.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2005] [Revised: 03/29/2006] [Accepted: 03/30/2006] [Indexed: 11/25/2022]
Abstract
The resurgence of tuberculosis along with the increased resistance of Mycobacterium tuberculosis has emphasized the need for timely susceptibility testing for control of the disease. Previous studies have shown that rapid susceptibility testing can be accomplished for isoniazid, ethambutol, and rifampin using the flow cytometric assays. In this study we compared the flow cytometric susceptibility assay with the BACTEC TB 460 and BACTEC MGIT 960 for pyrazinamide (PZA). There was 93% agreement between the BACTEC MGIT 960 and the flow cytometric methods for 100 microg/mL of PZA. Additionally, there was a 95% and 86% agreement between the BACTEC TB 460 and flow cytometric methods for 50 microg/mL and 100 microg/mL of PZA, respectively. These findings show that susceptibility testing by the flow cytometric assay is accurate. Most importantly, susceptibility results by the flow cytometric assay were available 24 h after initiation of the testing procedure. The advantages of simplicity, speed and accuracy make the flow cytometric susceptibility assay an immediate impact technology to improve patient care.
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Affiliation(s)
- Beth A Fredricks
- Wisconsin State Laboratory of Hygiene, University of Wisconsin, Madison, WI 53706, USA
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9
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Pina-Vaz C, Costa-de-Oliveira S, Rodrigues AG. Safe susceptibility testing of Mycobacterium tuberculosis by flow cytometry with the fluorescent nucleic acid stain SYTO 16. J Med Microbiol 2005; 54:77-81. [PMID: 15591259 DOI: 10.1099/jmm.0.45627-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The time needed to obtain susceptibility results of Mycobacterium tuberculosis using classical methodologies is still too long, and flow cytometry is a promising technique in the setting of the clinical laboratory, giving fast results. A safe, reliable and rapid method to study susceptibility to streptomycin, isoniazide, rifampicin and ethambutol is described. Isolates of mycobacteria, grown for 72 h in the absence or presence of antimycobacterial drugs in the mycobacteria growth indicator tube (MGIT), were heat-killed, stained with SYTO 16 (a nucleic acid fluorescent stain that only penetrates cells with severe lesion of the membrane) and then analysed by flow cytometry. Sixteen strains with different susceptibility patterns were tested and an excellent correlation with the BACTEC MGIT 960 protocol for susceptibility was shown. In contrast to resistant strains, sensitive strains lose their cellular integrity after incubation with antimycobacterial drugs, allowing SYTO 16 to penetrate the cells. Comparing the intensity of fluorescence of Mycobacterium cells incubated with antimycobacterial drugs with that of drug-free cells, after staining with SYTO 16, it was possible to distinguish between sensitive, intermediate and resistant phenotypes. Other cytometric assays have been described for mycobacteria susceptibility testing but these have lower accuracy and safety. The described flow cytometric assay is a simple, fast, safe and accurate way to determine susceptibility of M. tuberculosis.
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Affiliation(s)
- C Pina-Vaz
- Department of Microbiology, Faculty of Medicine, University of Porto, Alameda Prof. Hernani Monteiro, 4200 Porto, Portugal 2IPATIMUP - Institute of Pathology and Molecular Immunology of the University of Porto, Portugal 3Department of Microbiology, Hospital de S. João, Alameda Prof. Hernani Monteiro, 4200 Porto, Portugal
| | - S Costa-de-Oliveira
- Department of Microbiology, Faculty of Medicine, University of Porto, Alameda Prof. Hernani Monteiro, 4200 Porto, Portugal 2IPATIMUP - Institute of Pathology and Molecular Immunology of the University of Porto, Portugal 3Department of Microbiology, Hospital de S. João, Alameda Prof. Hernani Monteiro, 4200 Porto, Portugal
| | - A G Rodrigues
- Department of Microbiology, Faculty of Medicine, University of Porto, Alameda Prof. Hernani Monteiro, 4200 Porto, Portugal 2IPATIMUP - Institute of Pathology and Molecular Immunology of the University of Porto, Portugal 3Department of Microbiology, Hospital de S. João, Alameda Prof. Hernani Monteiro, 4200 Porto, Portugal
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10
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Vanitha JD, Paramasivan CN. Evaluation of microplate Alamar blue assay for drug susceptibility testing of Mycobacterium avium complex isolates. Diagn Microbiol Infect Dis 2004; 49:179-82. [PMID: 15246507 DOI: 10.1016/j.diagmicrobio.2004.04.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2003] [Accepted: 04/01/2004] [Indexed: 10/26/2022]
Abstract
Fifty-one clinical isolates and 5 clarithromycin-resistant mutants of Mycobacterium avium complex (MAC) were tested for their susceptibility to clarithromycin by microplate Alamar blue assay (MABA). The susceptibility results were compared with the results obtained by the BACTEC 460 method. All clinical isolates were susceptible, while all mutants were resistant to clarithromycin by BACTEC. Eighty-six percent of the clinical isolates were susceptible by MABA, and one of the resistant mutants was misclassified as susceptible by this method. The overall agreement between MABA and BACTEC was 86%, indicating the usefulness of MABA in drug susceptibility testing of MAC.
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11
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Gökahmetoglu S, Nedret Koç A, Patiroglu T. Antifungal susceptibility testing of Candida albicans by flow cytometry. Mycoses 2003; 46:307-11. [PMID: 12950899 DOI: 10.1046/j.1439-0507.2003.00903.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Antifungal susceptibilities of 28 Candida albicans isolates and two quality control strains to amphotericin B and fluconazole were determined by flow cytometry and microdilution method. Minimum inhibitory concentrations (MICs) obtained by flow cytometry were compared with the results obtained by The National Committee for Clinical Laboratory Standards Subcommittee (NCCLS) broth microdilution method. The agreement of results (within two dilution) obtained was found as 96 and 93% for amphotericin B and fluconazole, respectively. At least 24 h incubation was required for reading the microdilution assays. Four hours of incubation was required for fluconazole, whereas 2-h incubation was sufficient for amphotericin B to provide MIC by flow cytometry. Results of this study show that flow cytometry provides a rapid and sensitive in vitro method for antifungal susceptibility testing of Candida albicans isolates.
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Affiliation(s)
- Selma Gökahmetoglu
- Department of Microbiology, Erciyes University Medical Faculty, TR-38039 Kayseri, Turkey.
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12
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Walberg M, Steen HB. Flow cytometric monitoring of bacterial susceptibility to antibiotics. Methods Cell Biol 2001; 64:553-66. [PMID: 11070855 DOI: 10.1016/s0091-679x(01)64029-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- M Walberg
- Institute of Medical Microbiology, National Hospital, University of Oslo, Norway
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13
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D'Haese E, Nelis HJ. Effect of antibiotics on viability staining of Escherichia coli in solid phase cytometry. J Appl Microbiol 2000; 89:778-84. [PMID: 11119151 DOI: 10.1046/j.1365-2672.2000.01179.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Solid phase cytometry (SPC) has been investigated as a tool to assess the effect of antibiotics on the viability of Escherichia coli. After exposure of the cells to the antibiotic, they are retained on a polyester membrane filter and labelled using a fluorescein derivative as a substrate for intracellular esterases. The number of fluorescent bacteria is automatically counted in an Ar laser scanning device. In the presence of nutrients, all antibiotics tested in concentrations exceeding the MIC inhibited the multiplication of cells but not the labelling per se. However, when no nutrients were added, the cells did not multiply, and inhibition of the fluorescent staining was only observed for membrane permeabilizing antibiotics, even at sub-MIC concentrations. The selective detection by SPC of membrane-permeabilizing antibiotics corroborates the requirement of membrane integrity for viability labelling of bacteria. This selectivity has been exploited to develop a method for the detection of colistin residues in milk.
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Affiliation(s)
- E D'Haese
- Laboratory for Pharmaceutical Microbiology, Ghent University, Belgium
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14
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Vives-Rego J, Lebaron P, Nebe-von Caron G. Current and future applications of flow cytometry in aquatic microbiology. FEMS Microbiol Rev 2000; 24:429-48. [PMID: 10978545 DOI: 10.1111/j.1574-6976.2000.tb00549.x] [Citation(s) in RCA: 170] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Flow cytometry has become a valuable tool in aquatic and environmental microbiology that combines direct and rapid assays to determine numbers, cell size distribution and additional biochemical and physiological characteristics of individual cells, revealing the heterogeneity present in a population or community. Flow cytometry exhibits three unique technical properties of high potential to study the microbiology of aquatic systems: (i) its tremendous velocity to obtain and process data; (ii) the sorting capacity of some cytometers, which allows the transfer of specific populations or even single cells to a determined location, thus allowing further physical, chemical, biological or molecular analysis; and (iii) high-speed multiparametric data acquisition and multivariate data analysis. Flow cytometry is now commonly used in aquatic microbiology, although the application of cell sorting to microbial ecology and quantification of heterotrophic nanoflagellates and viruses is still under development. The recent development of laser scanning cytometry also provides a new way to further analyse sorted cells or cells recovered on filter membranes or slides. The main infrastructure limitations of flow cytometry are: cost, need for skilled and well-trained operators, and adequate refrigeration systems for high-powered lasers and cell sorters. The selection and obtaining of the optimal fluorochromes, control microorganisms and validations for a specific application may sometimes be difficult to accomplish.
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Affiliation(s)
- J Vives-Rego
- Departament de Microbiologia, Universitat de Barcelona, Barcelona, Spain.
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15
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Bonecini-Almeida MG. Flow cytometry as a tool to identify Mycobacterium tuberculosis interaction with the immune system and drug susceptibility. Mem Inst Oswaldo Cruz 2000; 95:491-4. [PMID: 10904404 DOI: 10.1590/s0074-02762000000400008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
Flow cytometric analysis is a useful and widely employed tool to identify immunological alterations caused by different microorganisms, including Mycobacterium tuberculosis. However, this tool can be used for several others analysis. We will discuss some applications for flow cytometry to the study of M. tuberculosis, mainly on cell surface antigens, mycobacterial secreted proteins, their interaction with the immune system using inflammatory cells recovered from peripheral blood, alveolar and pleura spaces and the influence of M. tuberculosis on apoptosis, and finally the rapid determination of drug susceptibility. All of these examples highlight the usefulness of flow cytometry in the study of M. tuberculosis infection.
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Affiliation(s)
- M G Bonecini-Almeida
- Laboratório de Imunologia Celular, Departamento de Microbiologia e Imunologia, Centro de Pesquisa Hospital Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, Brasil.
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16
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Vena RM, Munson EL, DeCoster DJ, Croke CL, Fett DB, Callister SM, Schell RF. Flow cytometric testing of susceptibilities of Mycobacterium avium to amikacin, ciprofloxacin, clarithromycin and rifabutin in 24 hours. Clin Microbiol Infect 2000; 6:368-75. [PMID: 11168153 DOI: 10.1046/j.1469-0691.2000.00100.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To develop a biologically safe flow cytometric susceptibility test that depends on detection and enumeration of actively growing Mycobacterium avium organisms in drug-free and antimycobacterial agent-containing medium. METHODS Prior to analysis by flow cytometry, all M. avium susceptibility test samples were inactivated by exposure to paraformaldehyde. The susceptibilities of 20 clinical isolates of M. avium to amikacin, ciprofloxacin, clarithromycin, and rifabutin were tested by the flow cytometric and BACTEC methods. RESULTS Agreement was 97% between the results of the two methods. The results of flow cytometric susceptibility tests were available 24 h after inoculation of drug-containing medium, while the BACTEC method required 4-8 days to complete. CONCLUSIONS The flow cytometric assay is safe, simple and reproducible.
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Affiliation(s)
- R M Vena
- Wisconsin State Laboratory of Hygiene, Madison, Wisconsin, USA
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17
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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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18
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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: 111] [Impact Index Per Article: 4.6] [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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Kirk SM, Schell RF, Moore AV, Callister SM, Mazurek GH. Flow cytometric testing of susceptibilities of Mycobacterium tuberculosis isolates to ethambutol, isoniazid, and rifampin in 24 hours. J Clin Microbiol 1998; 36:1568-73. [PMID: 9620378 PMCID: PMC104878 DOI: 10.1128/jcm.36.6.1568-1573.1998] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Susceptibility testing of Mycobacterium tuberculosis is seriously limited by the time required to obtain results. We show that susceptibility testing of clinical isolates of M. tuberculosis can be accomplished rapidly with acceptable accuracy by using flow cytometry. The susceptibilities of 35 clinical isolates of M. tuberculosis to various concentrations of isoniazid, rifampin, and ethambutol were tested by the agar proportion method and by flow cytometry. Agreement between the results from the two methods was 95, 92, and 83% for isoniazid, ethambutol, and rifampin, respectively. Only 11 discrepancies were detected among 155 total tests. The results of flow cytometric susceptibility tests were available within 24 h of inoculation of drug-containing medium, while the proportion method required 3 weeks to complete. The flow cytometric method is also simple to perform.
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Affiliation(s)
- S M Kirk
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison 53706, USA
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Kirk SM, Mazurek GH, Callister SM, Moore AV, Schell RF. Mycobacterium tuberculosis susceptibility results in 24 hours by using flow cytometry. ACTA ACUST UNITED AC 1998. [DOI: 10.1016/s0196-4399(00)89195-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Kirk SM, Callister SM, Lim LC, Schell RF. Rapid susceptibility testing of Candida albicans by flow cytometry. J Clin Microbiol 1997; 35:358-63. [PMID: 9003596 PMCID: PMC229580 DOI: 10.1128/jcm.35.2.358-363.1997] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The emerging magnitude of human fungal infections has renewed interest in developing rapid and standardized methods for susceptibility testing. We demonstrated that susceptibility testing of Candida albicans can be accomplished rapidly by using flow cytometry. Test results were available within 8 to 24 h after C. albicans isolates were incubated with amphotericin B, itraconazole, and flucytosine. This is an improvement of 24 to 60 h in the time to availability of susceptibility test results compared to the time to availability of National Committee for Clinical Laboratory Standards-recommended broth macrodilution test results. In addition, the flow cytometric endpoints, mean channel fluorescence, and number of fluorescence-labeled C. albicans cells were easy to interpret for greater sensitivity and reliability. Flow cytometry provides a more accurate means of obtaining antifungal susceptibility test results.
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Affiliation(s)
- S M Kirk
- Wisconsin State Laboratory of Hygiene, University of Wisconsin, Madison 53706, USA
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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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