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Abavisani M, Khayami R, Hoseinzadeh M, Kodori M, Kesharwani P, Sahebkar A. CRISPR-Cas system as a promising player against bacterial infection and antibiotic resistance. Drug Resist Updat 2023; 68:100948. [PMID: 36780840 DOI: 10.1016/j.drup.2023.100948] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 01/25/2023] [Accepted: 02/07/2023] [Indexed: 02/12/2023]
Abstract
The phenomenon of antibiotic resistance (AR) and its increasing global trends and destructive waves concerns patients and the healthcare system. In order to combat AR, it is necessary to explore new strategies when the current antibiotics fail to be effective. Thus, knowing the resistance mechanisms and appropriate diagnosis of bacterial infections may help enhance the sensitivity and specificity of novel strategies. On the other hand, resistance to antimicrobial compounds can spread from resistant populations to susceptible ones. Antimicrobial resistance genes (ARGs) significantly disseminate AR via horizontal and vertical gene transfer. The clustered regularly interspaced short palindromic repeats (CRISPR)-Cas system is a member of the bacterial immune system with the ability to remove the ARGs; therefore, it can be introduced as an effective and innovative strategy in the battle against AR. Here, we reviewed CRISPR-based bacterial diagnosis technologies. Moreover, the strategies to battle AR based on targeting bacterial chromosomes and resistance plasmids using the CRISPR-Cas system have been explained. Besides, we have presented the limitations of CRISPR delivery and potential solutions to help improve the future development of CRISPR-based platforms.
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Affiliation(s)
- Mohammad Abavisani
- Student research committee, Mashhad University of Medical Sciences, Mashhad, the Islamic Republic of Iran; Department of Microbiology and Virology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, the Islamic Republic of Iran
| | - Reza Khayami
- Department of Medical Genetics and Molecular Medicine, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, the Islamic Republic of Iran
| | - Melika Hoseinzadeh
- Student research committee, Mashhad University of Medical Sciences, Mashhad, the Islamic Republic of Iran
| | - Mansoor Kodori
- Non communicable Diseases Research Center, Bam University of Medical sciences, Bam, the Islamic Republic of Iran
| | - Prashant Kesharwani
- Department of Pharmaceutics, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi 110062, India; Center for Transdisciplinary Research, Department of Pharmacology, Saveetha Dental College, Saveetha Institute of Medical and Technical Science, Chennai, India
| | - Amirhossein Sahebkar
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, the Islamic Republic of Iran; Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, the Islamic Republic of Iran; Department of Biotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, the Islamic Republic of Iran.
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Park S, Lee S, Kim HS, Choi HJ, Jeong OC, Lin R, Cho Y, Lee MH. Square microchannel enables to focus and orient ellipsoidal Euglena gracilis cells by two-dimensional acoustic standing wave. Mikrochim Acta 2022; 189:331. [PMID: 35969307 DOI: 10.1007/s00604-022-05439-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 07/31/2022] [Indexed: 11/26/2022]
Abstract
Flow cytometry has become an indispensable tool for counting, analyzing, and sorting large cell populations in biological research and medical practice. Unfortunately, it has limitations in the analysis of non-spherically shaped cells due to the variation of their alignment with respect to the flow direction and, hence, the optical interrogation axis, resulting in unreliable cell analysis. Here, we present a simple on-chip acoustofluidic method to fix the orientation of ellipsoidal cells and focus them into a single, aligned stream. Specifically, by generating acoustic standing waves inside a 100 ⋅ 100 µm square-shaped microchannel, we successfully aligned and focused up to 97.7% of a population of Euglena gracilis (an ellipsoidal shaped microalgal species) cells in the center of the microchannel with high precision at a volume rate of 25 to 200 µL min-1. Uniform positioning of ellipsoidal cells is essential for making flow cytometry applicable to the investigation of a greater variety of cell populations and is expected to be beneficial for ecological studies and aquaculture.
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Affiliation(s)
- Sungryul Park
- School of Integrative Engineering, Chung-Ang University, Seoul, 06974, Republic of Korea
| | | | - Hyun Soo Kim
- Department of Electronic Engineering, Kwangwoon University, Seoul, 01897, Republic of Korea
| | - Hong Jin Choi
- Department of Digital Anti-Aging Health Care, Inje University, Gimhae-si, 50834, Republic of Korea
| | - Ok Chan Jeong
- Department of Biomedical Engineering, Inje University, Gimhae-si, 50834, Republic of Korea
| | - Ruixian Lin
- School of Integrative Engineering, Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Younghak Cho
- Department of Mechanical Design and Robot Engineering, Seoul National University of Science & Technology, Seoul, 01811, Republic of Korea.
| | - Min-Ho Lee
- School of Integrative Engineering, Chung-Ang University, Seoul, 06974, Republic of Korea.
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Fast and sensitive detection of Bacillus anthracis spores by immunoassay. Appl Environ Microbiol 2012; 78:6491-8. [PMID: 22773632 DOI: 10.1128/aem.01282-12] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacillus anthracis is one of the most dangerous potential biological weapons, and it is essential to develop a rapid and simple method to detect B. anthracis spores in environmental samples. The immunoassay is a rapid and easy-to-use method for the detection of B. anthracis by means of antibodies directed against surface spore antigens. With this objective in view, we have produced a panel of monoclonal antibodies against B. anthracis and developed colorimetric and electrochemiluminescence (ECL) immunoassays. Using Meso Scale Discovery ECL technology, which is based on electrochemiluminescence (ECL) detection utilizing a sulfo-Tag label that emits light upon electrochemical stimulation (using a dedicated ECL plate reader, an electrical current is placed across the microplate with electrodes integrated into the bottom of the plate, resulting in a series of electrically induced reactions leading to a luminescent signal), a detection limit ranging between 0.3 × 10(3) and 10(3) CFU/ml (i.e., 30 to 100 spores per test), depending on the B. anthracis strain assayed, was achieved. In complex matrices (5 mg/ml of soil or simulated powder), the detection level (without any sample purification or concentration) was never altered more than 3-fold compared with the results obtained in phosphate-buffered saline.
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Hammes F, Egli T. Cytometric methods for measuring bacteria in water: advantages, pitfalls and applications. Anal Bioanal Chem 2010; 397:1083-95. [DOI: 10.1007/s00216-010-3646-3] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2010] [Revised: 03/05/2010] [Accepted: 03/08/2010] [Indexed: 11/30/2022]
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5
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Cronin U, Wilkinson M. The potential of flow cytometry in the study of Bacillus cereus. J Appl Microbiol 2010; 108:1-16. [DOI: 10.1111/j.1365-2672.2009.04370.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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6
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Flow cytometry applications in the food industry. J Ind Microbiol Biotechnol 2009; 36:999-1011. [DOI: 10.1007/s10295-009-0608-x] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Accepted: 06/02/2009] [Indexed: 11/25/2022]
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Schellenberg J, Smoragiewicz W, Karska-Wysocki B. A rapid method combining immunofluorescence and flow cytometry for improved understanding of competitive interactions between lactic acid bacteria (LAB) and methicillin-resistant S. aureus (MRSA) in mixed culture. J Microbiol Methods 2005; 65:1-9. [PMID: 16154216 DOI: 10.1016/j.mimet.2005.06.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2005] [Revised: 06/07/2005] [Accepted: 06/08/2005] [Indexed: 11/20/2022]
Abstract
The increasing frequency of methicillin-resistant Staphylococcus aureus (MRSA) infections in hospital and community settings highlights the need for effective anti-MRSA agents that will not contribute to the growing problem of antibiotic resistance. Lactic acid bacteria (LAB) are known to exclude various pathogens through multiple mechanisms. In vitro models studying interactions of pathogens and LAB in mixed cultures use selective agar plates to quantify changes in target populations. We applied commercially available S. aureus-specific polyclonal antibodies conjugated with fluorescein isothiocyanate (FITC) for this purpose, producing a bright green signal that clearly differentiates S. aureus from LAB species when mixed cultures are analyzed by flow cytometry and fluorescent microscopy. Flow cytometry of mixed cultures revealed a much larger population of MRSA cells than was detectable using selective agar plates. To our knowledge, this is the first time immunofluorescent flow cytometry has been applied to the study of competitive exclusion in mixed bacterial populations over time.
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Affiliation(s)
- John Schellenberg
- Département des sciences biologiques, Université du Québec à Montréal, Pavillon des Sciences, 1200, rue St. Alexandre, Montréal, Québec H3B 3H5 Canada.
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Yitzhaki S, Barnea A, Keysary A, Zahavy E. New approach for serological testing for leptospirosis by using detection of leptospira agglutination by flow cytometry light scatter analysis. J Clin Microbiol 2004; 42:1680-5. [PMID: 15071025 PMCID: PMC387560 DOI: 10.1128/jcm.42.4.1680-1685.2004] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Leptospirosis is considered an important reemerging infectious disease worldwide. The standard and most widespread method for the diagnosis of leptospirosis is the microscopic agglutination test (MAT). This test is laborious and time-consuming, and the interpretation of the results is subjective. In the present work we describe an application of flow cytometry (FCM) as a tool for the serological diagnosis of leptospirosis. The analysis is based on the sensitivity of FCM to the size and shape of the bacteria analyzed by measurement of light scatter parameters: forward scatter (FSC) and side scatter (SSC). The addition of positive serum to an infecting leptospiral serovar results in a shift of the light scatter parameter to a different location with higher FSC and SSC values, indicating the formation of leptospiral aggregates. By using immunofluorescent staining, we have shown that the large particles formed are the agglutinated leptospires. Quantification of the agglutination process has been achieved by calculating an agglutination factor (Af), based on changes in the light scatter parameters measured by FCM. Af enables us to determine the specificity of the serological reaction of the patient serum with each leptospiral serovar. In this work, 27 serum samples from 18 leptospirosis patients were tested by both the MAT and the FCM techniques, in which each serum sample was tested against 13 serovars. Twenty-six human serum samples derived from patients with a variety of other defined illnesses were used as negative controls and enabled us to define the Af threshold value as < 9.3 for negative patients, while any value higher than that would be a positive result for leptospirosis. Compared to MAT, the FCM technique was found to be more specific and sensitive, especially in identifying the serogroup in the acute phase of the disease. The whole process was found to be rapid and took less than 1.5 h. Moreover, FCM analysis is objective and can be automated for the handling of large numbers of samples.
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Affiliation(s)
- S Yitzhaki
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness-Ziona 74100, Israel.
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10
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Zahavy E, Fisher M, Bromberg A, Olshevsky U. Detection of frequency resonance energy transfer pair on double-labeled microsphere and Bacillus anthracis spores by flow cytometry. Appl Environ Microbiol 2003; 69:2330-9. [PMID: 12676717 PMCID: PMC154795 DOI: 10.1128/aem.69.4.2330-2339.2003] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Development of an ultrasensitive biosensor for biological hazards in the environment is a major need for pollutant control and for the detection of biological warfare. Fluorescence methods combined with immunodiagnostic methods are the most common. To minimize background noise, arising from the unspecific adsorption effect, we have adapted the FRET (frequency resonance energy transfer) effect to the immunofluorescence method. FRET will increase the selectivity of the diagnosis process by introducing a requirement for two different reporter molecules that have to label the antigen surface at a distance that will enable FRET. Utilizing the multiparameter capability of flow cytometry analysis to analyze the double-labeling/FRET immunostaining will lead to a highly selective and sensitive diagnostic method. This work examined the FRET interaction of fluorescence-labeled avidin molecules on biotin-coated microspheres as a model system. As target system, we have used labeled polyclonal antibodies on Bacillus anthracis spores. The antibodies used were purified immunoglobulin G (IgG) molecules raised in rabbits against B. anthracis exosoporium components. The antibodies were fluorescence labeled by a donor-acceptor chromophore pair, alexa488 as a donor and alexa594 as an acceptor. On labeling the spores with alexa488-IgG as a donor and alexa594-IgG as an acceptor, excitation at 488 nm results in quenching of the alexa-488 fluorescence (E(q) = 35%) and appearance of the alexa594 fluorescence (E(s) = 22%), as detected by flow cytometry analysis. The FRET effect leads to a further isolated gate (FL1/FL3) for the target spores compared to competitive spores such as B. thuringiensis subsp. israelensis and B. subtilis. This new approach, combining FRET labeling and flow cytometry analysis, improved the selectivity of the B. anthracis spores by a factor of 10 with respect to B. thuringiensis subsp. israelensis and a factor of 100 with respect to B. subtilis as control spores.
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Affiliation(s)
- E Zahavy
- Department of Physical Chemistry, Israel Institute for Biological Research, Ness-Ziona 74100, Israel.
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11
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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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12
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Affiliation(s)
- S A Sincock
- Purdue Cytometry Laboratories, Department of Basic Medical Sciences, Purdue University, West Lafayette, Indiana 47907, USA
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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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14
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Hewitt CJ, Nebe-Von Caron G, Nienow AW, McFarlane CM. Use of multi-staining flow cytometry to characterise the physiological state of Escherichia coli W3110 in high cell density fed-batch cultures. Biotechnol Bioeng 1999; 63:705-11. [PMID: 10397827 DOI: 10.1002/(sici)1097-0290(19990620)63:6<705::aid-bit8>3.0.co;2-m] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
High cell density fed-batch fermentations of Escherichia coli W3110 have been carried out at specific growth rates of less than 0.3 h-1, to investigate the effect of glucose limitation on the physiological state of individual cells. After an initial exponential batch phase, the feed rate was held constant and a final dry cell weight of approximately 50 g per litre was achieved. The fermentations were monitored by mass spectrometry whilst measurements of pH, DOC, CFU/mL, TCN, OD500nm and residual glucose concentrations were made. Satisfactory and reproducible results were obtained. Flow cytometric analysis of cells in broth samples, based on either of two multi-staining protocols, revealed a progressive change in cell physiological state throughout the course of the fermentations. From these measurements it was concluded that the loss in reproductive viability towards the end of the fed-batch process is due to cell death and not due to the formation of a "viable but nonculturable state" as had previously been reported. Since the presence of a high proportion of dead or dying cells at any time during a fermentation has a detrimental effect on the synthesis of any desired product it is proposed that an on-line flow cytometric analysis and control strategy could be used as a means of increasing overall process efficiency.
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Affiliation(s)
- C J Hewitt
- Centre for Bioprocess Engineering, School of Chemical Engineering, The University of Birmingham, Edgbaston, B15 2TT, U.K.
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15
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Rapid preparation procedure for staining of exponentially growing P. vulgaris cells with ethidium bromide: a flow cytometry-based study of probe uptake under various conditions. J Microbiol Methods 1998. [DOI: 10.1016/s0167-7012(98)00072-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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16
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Roth BL, Poot M, Yue ST, Millard PJ. Bacterial viability and antibiotic susceptibility testing with SYTOX green nucleic acid stain. Appl Environ Microbiol 1997; 63:2421-31. [PMID: 9172364 PMCID: PMC168536 DOI: 10.1128/aem.63.6.2421-2431.1997] [Citation(s) in RCA: 392] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
A fluorescent nucleic acid stain that does not penetrate living cells was used to assess the integrity of the plasma membranes of bacteria. SYTOX Green nucleic acid stain is an unsymmetrical cyanine dye with three positive charges that is completely excluded from live eukaryotic and prokaryotic cells. Binding of SYTOX Green stain to nucleic acids resulted in a > 500-fold enhancement in fluorescence emission (absorption and emission maxima at 502 and 523 nm, respectively), rendering bacteria with compromised plasma membranes brightly green fluorescent. SYTOX Green stain is readily excited by the 488-nm line of the argon ion laser. The fluorescence signal from membrane-compromised bacteria labeled with SYTOX Green stain was typically > 10-fold brighter than that from intact organisms. Bacterial suspensions labeled with SYTOX Green stain emitted green fluorescence in proportion to the fraction of permeabilized cells in the population, which was quantified by microscopy, fluorometry, or flow cytometry. Flow cytometric and fluorometric approaches were used to quantify the effect of beta-lactam antibiotics on the cell membrane integrity of Escherichia coli. Detection and discrimination of live and permeabilized cells labeled with SYTOX Green stain by flow cytometry were markedly improved over those by propidium iodide-based tests. These studies showed that bacterial labeling with SYTOX Green stain is an effective alternative to conventional methods for measuring bacterial viability and antibiotic susceptibility.
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Affiliation(s)
- B L Roth
- Molecular Probes, Inc., Eugene, Oregon 97402, USA
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17
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Wallner G, Steinmetz I, Bitter-Suermann D, Amann R. Combination of rRNA-Targeted Hybridization Probes and Immuno-Probes for the Identification of Bacteria by Flow Cytometry. Syst Appl Microbiol 1996. [DOI: 10.1016/s0723-2020(96)80028-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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18
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Frasa H, Benaissa-Trouw B, Tavares L, van Kessel K, Poppelier M, Kraaijeveld K, Verhoef J. Enhanced protection by use of a combination of anticapsule and antilipopolysaccharide monoclonal antibodies against lethal Escherichia coli O18K5 infection of mice. Infect Immun 1996; 64:775-81. [PMID: 8641781 PMCID: PMC173837 DOI: 10.1128/iai.64.3.775-781.1996] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
To study antibody-mediated protection against Escherichia coli peritonitis in BALB/c mice, monoclonal antibodies (MAbs) were generated against the capsule (K5) and the lipopolysaccharide (O18) of E. coli. Flow cytometric analysis with two selected immunoglobulin M MAbs revealed that bacteria were antigenically heterogeneous. Arbitrarily, three subpopulations in E. coli O18K5 cultures could be distinguished by double immunofluorescence. A subpopulation bound only the anti-K5 MAb, and another subpopulation bound only the anti-O18 MAb. An intermediate subpopulation, however, bound both MAbs. In agreement with this result, combinations of both MAbs enhanced phagocytosis of fluorescein isothiocyanate-labeled bacteria by human polymorphonuclear leukocytes and mouse macrophage J774 cells as well. In protection experiments, combinations of both MAbs, preincubated with 3 50% lethal doses of E. coli O18K5, protected all mice upon intraperitoneal challenge. Relatively high doses of either MAb alone proved to be not fully protective in this infection model. Protection of mice by the combination of MAbs was associated with significantly lower (P < 0.02) tumor necrosis factor levels in serum 90 min after challenge compared with any other treatment group. Similarly, prophylactic administration of MAbs yielded significantly lower (P < 0.01) tumor necrosis factor levels in mice that received the combination of MAbs than in any other treatment group.
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Affiliation(s)
- H Frasa
- Eijkman-Winkler Institute for Medical Microbiology, University Hospital, Utrecht, The Netherlands
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19
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Schloter M, Assmus B, Hartmann A. The use of immunological methods to detect and identify bacteria in the environment. Biotechnol Adv 1995; 13:75-90. [PMID: 14537146 DOI: 10.1016/0734-9750(94)00023-6] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Immunological detection methods have become increasingly important in microbial ecology for the tracking of specific microorganisms and for community analysis. For a reliable application of these techniques, the monoclonal antibodies or polyclonal antisera used have to fulfill several quality criteria. Cross reactivity, cellular localization of the antigenic determinant, affinity characteristics and the expression of the antigenic determinant at environmental conditions have to be determined. Immunological methods can be used for the identification, quantification and enrichment of specific bacteria in extracts as well as for the visualization of cells in situ. The sensitivity of advanced immunological methods can be compared to PCR techniques. Using image processing of epifluorescence micrographs or confocal laser scanning microscopy, the immunofluorescence approach can now be applied to study complex environmental samples.
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Affiliation(s)
- M Schloter
- GSF-Forschungszentrum für Umwelt und Gesundheit, Institut für Bodenökologie, Neuherberg, Postfach 1129, D-85758 Oberschleissheim, Germany
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20
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Jernaes MW, Steen HB. Staining of Escherichia coli for flow cytometry: influx and efflux of ethidium bromide. CYTOMETRY 1994; 17:302-9. [PMID: 7875037 DOI: 10.1002/cyto.990170405] [Citation(s) in RCA: 85] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In an attempt to develop procedures for nucleic acid staining of bacteria for clinical routine assays, the uptake of ethidium bromide (EB) in wild-type Escherichia coli was studied using flow cytometry. Phosphate-buffered saline (PBS) containing EDTA or Tris significantly increased the net uptake of EB compared to PBS only. However, in the majority of the cells, the net uptake reached a constant level that was only a few percent of that of fully permeabilized cells, apparently due to the activity of a metabolically driven efflux pump. When cells were exposed to cold shock (0 degrees C for 30 min) in the presence of Tris or EDTA, the net uptake of dye was similar to that of fully permeabilized cells, whereas it was about half that value in PBS. When cold shock was given in growth medium, the cells split up into four subpopulations, with a net dye uptake ranging from that of fully permeabilized cells to less than 1% of that value. As expected, metabolic inhibitors (Na-azide, 2-deoxy-D-glucose, and CCCP) reduced efflux activity. However, fluorescence of metabolically inhibited cells never exceeded more than about half the value of that of dead cells, possibly reflecting conformational changes in DNA structure as a result of cell death.
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Affiliation(s)
- M W Jernaes
- Department of Biophysics, Norwegian Radium Hospital, Oslo
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21
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Pinder AC, McClelland RG. Rapid assay for pathogenic Salmonella organisms by immunofluorescence flow cytometry. J Microsc 1994; 176:17-22. [PMID: 7799425 DOI: 10.1111/j.1365-2818.1994.tb03495.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Multi-parameter flow cytometry was investigated for the rapid detection of specific serotypes of salmonellas (S. typhimurium and S. montevideo) labelled with fluorescent monoclonal antibodies, both in pure culture and in a typical food matrix (full-fat milk). In all cases, the method was accurate to levels of below 10(4) target cells per ml for a total assay time of about 30 min. After 6 h non-selective enrichment in the presence of a 10,000-fold excess of competing micro-organisms (Escherichia coli) the corresponding detection limit was about 20 cells ml-1. These results suggest that flow cytometry has significant potential for the detection of pathogenic micro-organisms in the food industry.
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Affiliation(s)
- A C Pinder
- Department of Food Biophysics, Norwich Laboratory, U.K
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22
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McClelland RG, Pinder AC. Detection of low levels of specific Salmonella species by fluorescent antibodies and flow cytometry. THE JOURNAL OF APPLIED BACTERIOLOGY 1994; 77:440-7. [PMID: 7989272 DOI: 10.1111/j.1365-2672.1994.tb03447.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The use of fluorescently-labelled monoclonal antibodies, with detection by multi-parameter flow cytometry, was investigated for the rapid detection of salmonellas in pure cultures. Accurate detection of specific Salmonella serotypes was demonstrated down to levels of below 10(4) cells ml-1 (within 30 min) and 1 cell ml-1 (after 6 h non-selective pre-enrichment). This level of sensitivity was attained even in the presence of high levels of other bacterial species that would otherwise have interfered with the results. With combinations of different antibodies, each with a unique fluorescent label, simultaneous analysis for two species was possible.
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Affiliation(s)
- R G McClelland
- Department of Food Biophysics, AFRC Institute of Food Research, Norwich Laboratory, UK
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van der Waaij LA, Mesander G, Limburg PC, van der Waaij D. Direct flow cytometry of anaerobic bacteria in human feces. CYTOMETRY 1994; 16:270-9. [PMID: 7924697 DOI: 10.1002/cyto.990160312] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We describe a flow cytometry method for analysis of noncultured anaerobic bacteria present in human fecal suspensions. Nonbacterial fecal compounds, bacterial fragments, and large aggregates could be discriminated from bacteria by staining with propidium iodide (PI) and setting a discriminator on PI fluorescence and by exclusion of events with large forward scatter. Since anaerobic bacteria, which account for over 99.9% of all fecal bacteria, die during sample preparation, a fixation step was not necessary. A second aim of this study was to investigate the technical possibility of measurement of in vivo IgA coating of fecal anaerobic bacteria as well as their bacterial size. Fecal samples of 22 healthy human volunteers were analyzed. The fluorescence distribution of IgA-coated bacteria labeled with fluorescein isothiocyanate (FITC)-anti-Hu-IgA had overlap with noncoated bacteria. However, with match region subtraction, detection of low levels of specific FITC fluorescence on IgA-coated bacteria was achieved. The median bacterial two-dimensional surface area was 1.0 microns2. To validate flow cytometry data, all samples were analyzed with an image analysis system as well. With this new method, a rapid evaluation of fecal flora with high sensitivity for specific FITC fluorescence is possible without culturing.
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Affiliation(s)
- L A van der Waaij
- Department of Medical Microbiology, University of Groningen, The Netherlands
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Allman R, Hann AC, Manchee R, Lloyd D. Characterization of bacteria by multiparameter flow cytometry. THE JOURNAL OF APPLIED BACTERIOLOGY 1992; 73:438-44. [PMID: 1447060 DOI: 10.1111/j.1365-2672.1992.tb05001.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
An arc-lamp based flow cytometer was used to obtain high resolution measurements of the light scattering characteristics and DNA contents of eight different bacteria. Light scatter profiles of bacteria are a useful first step when flow cytometry is used to characterize organisms. Scanning and transmission electron microscopy of the bacterial samples demonstrate that the structural basis of the light scattering profiles is not always clear, i.e. some organisms appear to have anomalous light scattering characteristics. The use of a third measurement parameter, DNA content, allowed much better discrimination of the organisms. Flow cytometry shows great promise as a method for the rapid discrimination and identification of bacterial populations.
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Affiliation(s)
- R Allman
- Department of Pure and Applied Biology, University of Wales College of Cardiff, UK
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25
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Nelson D, Neill W, Poxton IR. A comparison of immunoblotting, flow cytometry and ELISA to monitor the binding of anti-lipopolysaccharide monoclonal antibodies. J Immunol Methods 1990; 133:227-33. [PMID: 2230140 DOI: 10.1016/0022-1759(90)90363-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
This study was designed to assess the use of flow cytometry to observe the binding, under physiological conditions, of anti-lipopolysaccharide (LPS) monoclonal antibodies (mAbs) to whole bacteria, and to compare this with the more conventional whole cell ELISA and immunoblotting techniques. The bacteria consisted of two clinical isolates of E. coli 018:K1 and 06:K5 and two isogenic mutants of the 018 parent: a non-capsulate (018:K-) and a rough mutant (018rf). Two cross-reactive anti-core mAbs and one 018 0-antigen-specific mAb were used. ELISA and flow cytometry showed that capsule and O-polysaccharide influenced the binding of mAbs to the bacteria, whilst the latter technique demonstrated that sub-populations existed. Immunoblotting showed the two anti-core mAbs to be different, one bound only to core which was not substituted with O-antigen, whilst the other bound both to substituted and unsubstituted core. This comparison for monitoring the binding of anti-LPS mAbs demonstrates the potential use of flow cytometry in bacterial cell surface research, and complements results obtained by ELISA and immunoblotting.
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Affiliation(s)
- D Nelson
- Bacteriology Department, University of Edinburgh Medical School, U.K
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Obernesser MS, Socransky SS, Stashenko P. Limit of resolution of flow cytometry for the detection of selected bacterial species. J Dent Res 1990; 69:1592-8. [PMID: 1697868 DOI: 10.1177/00220345900690091101] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The enumeration of bacteria in dental plaque samples is a vital but time-consuming procedure that uses standard cultural methods. Flow cytometry has proven to be a useful tool for the analysis of eukaryotic cells. In the present investigation, the utility of this technology for the enumeration of bacteria in mixtures was explored. Rabbit antisera were produced against the putative periodontal pathogens A. actinomycetemcomitans, B. intermedius, B. gingivalis, E. corrodens, W. recta, B. forsythus, as well as the frequently isolated supragingival species S. sanguis. Cross-reactive antibodies were removed by absorption, and the specificity of each antiserum was confirmed by being tested against a panel of 235 oral microbial strains (79 genera; 94 species) by means of ELISA. Conditions were established for the indirect immunofluorescent labeling of cells without agglutination with use of a goat anti-rabbit Ig-FITC second antibody. When an internal bead standard was used, it was found that unstained bacteria were enumerated by light-scattering parameters with poor efficiency (less than 3%). However, cells exposed to FITC either in the presence of specific or non-specific first antibody were enumerated with high efficiency (102.6 +/- 29.3%), indicating that a small amount of non-specific binding of fluorochrome facilitates bacterial detection. Clear discrimination between specifically- and non-specifically-stained bacteria was achieved with all six rabbit antisera. Mixtures of known composition were made (1) with pure cultures or (2) with a known species and supragingival plaque devoid of that species by culture. The results from both approaches with various species combinations revealed that the limit of resolution for accurate quantitation of a selected species was approximately 5%, although specific organisms could be detected qualitatively when present at approximately 1%.
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Affiliation(s)
- M S Obernesser
- Department of Microbiology, Forsyth Dental Center, Boston, Massachusetts 02115
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27
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Miller JS, Quarles JM. Flow cytometric identification of microorganisms by dual staining with FITC and PI. CYTOMETRY 1990; 11:667-75. [PMID: 1696535 DOI: 10.1002/cyto.990110603] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The identification of microorganisms by flow cytometry was evaluated by using a double staining technique with propidium iodide and fluorescein isothiocyanate and a two dimensional analysis. A diverse group of 19 different species and strains of microorganisms was tested to determine if they could be differentiated by flow cytometry. The organisms tested displayed characteristic and distinct two dimensional fluorescent patterns which allowed ready grouping and differentiation into subsets of organisms. The slopes and correlation coefficients of the histograms and the ratio of red to green signals expressed these differences quantitatively and allowed organisms to be placed into one of three groups based on these values. In some instances, as with Streptococcus pneumoniae and pyogenes and Staphylococcus aureus and epidermidis, it was possible to distinguish between species of bacteria from the same genus. The use of dual dye labeling and flow cytometry provided a rapid method of identifying selected microorganisms and may be broadly applicable for the detection and identification of many bacteria and fungi.
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Affiliation(s)
- J S Miller
- Department of Medical Microbiology and Immunology, College of Medicine, Texas A&M University, College Station 77843-1114
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